text:
# Pandoc Markdown Table Without Header

A clean pandoc LaTeX template to convert your markdown files to PDF or LaTeX. In this file, you can edit a small number of styles in the document, including those that control the look of paragraphs, headings, captions, titles and subtitles, a basic table, and hyperlinks. Apply rmarkdown::render() outside the RStudio don't find pandoc. If the kable() output does not meet your needs, the pander package is an R pandoc writer that offers additional control for tables and other elements. Previously the parser tried to be efficient – if no end double quote was found, it would. So here's the final. The LaTeX package fancyhdr has provided several commands to customize the header and footer lines of your document. continues: string (default: 'Table continues below') passed to pandoc. The Makefile will turn any *. When you select the PDF output format, Markdown automatically renders a LaTeX table, but would also produce a correctly formatted table in MS Word, HTML, etc. The ioslides template has an attractive default style for tables so you shouldn't hesitate to add tables for presenting more complex sets of information. This was a mismatch between pandoc's docx, epub, latex, and markdown writers and the behavior of pandoc-citeproc, which actually looks for a div with id refs rather than one with class references. Pandoc is the "swiss-army" knife tool of format conversions: Its core source input format supported is Markdown (including any of the major MD "dialects" such as the flavors of GitHub and PHP plus several special extensions). Markdown is a popular text markup format, used on Stackoverflow, Github, and in many other places (including this guide). The library includes separate modules for each input and output format, so adding a new input or output format just requires adding a new module. The tables for format = 'markdown' also work for Pandoc when the pipe_tables extension is enabled (this is the default behavior for Pandoc >= 1. Inline styles for email. You can create a slide show broken up into sections by using the # and ## heading tags (you can also create a new slide without a header using a horizontal rule (----). As explained by John Gruber, the creator of markdown, it was not created to replace HTML, so there are situations we can't avoid using HTML. The pandoc parameter --columns=NUM can be used to define the length of lines in characters. The template is compatible with pandoc 2. The main use cases of the library are: printing small tables without hassle: just one function call, formatting is guided by the data itself. Pandoc實現了基本的Markdown語法外, 還加了一些extention. table aligns="LCR" caption="This is the **caption**" header="yes"} Fruit, Quantity, Price apples, 15, 3. Excerpt Markdown Style Comments From a File. The first official book authored by the core R Markdown developers that provides a comprehensive and accurate reference to the R Markdown ecosystem. md -o my_parsed_html. To see the output created by each of the commands below, click on the name of the output file:. A 2nd problem arose, in that, pandoc's markdown does not support pipe_tables by default. I personally am a huge fan of pandoc. 2 R Markdown components. Include a header block in your documents. Improve export and import via Pandoc. A paragraph not followed by a blank line subsumes any following paragraph, theme break, indented code block, list item, or table - these elements usually become ordinary text. Lots of ideas borrowed from Karl Browman's post. Please note that only the formats pandoc and markdown are portable, i. TOC, numbered/unnumbered sections, etc; Pandoc templates (how to write a template and apply it, how to pass variables to Pandoc templates) Customize CSS for HTML output. Sometimes is just better to rid off of all the dynamicity of the site to achieve better performance and semplicity with just the static part, this is true if we are talking about of a simple blog like this. The trick is to ensure that your tables are formatted such that they're readable in plain text. Improved computation of column widths in pipe tables. December 5, 2013 / Texts 0. Without the ". Over time, many Markdown implementations have appeared. md in the directory into PDF slides (*. Scripting with pandoc. table: numeric passed to pandoc. Creating Presentations Using Markdown and Pandoc. return pandoc. The master document, for example, consists of the YAML front matter and includes the children, which are themselves R Markdown documents without a YAML front matter. (When R Markdown output format is pdf, an image will be display instead of a real table generated with latex. 44 TUGboat, Volume 35 (2014), No. To create an ioslides presentation from R Markdown you specify the ioslides_presentation output format in the front-matter of your document. docx as well. Previously the parser tried to be efficient – if no end double quote was found, it would. Jonathan R. The text in an R Markdown document is written with the Markdown syntax. , format = 'latex' only works for LaTeX output documents. Hi, I am author of flextable. pdf,markdown,pandoc I create PDF documents from Markdown documents using the simplest pandoc command: pandoc my. markdown didn't used to get processed, as only. Python Markdown offers a flexible extension mechanism, which makes it possible to change and/or extend the behavior of the parser without having to edit the actual source files. list pandoc. If you need complex tables you will need to create them by hand or with a tool specifically designed for your output format. Handle table w/o following blank line in fenced div. I tried passing commands like \LaTeX or simple tables in latex through markdown, but mathml will not work on them. For example:. Latex Running Title. Remove “fallback” for doubleQuote parser. Markdown paired with pandoc provides a simple interface to harness the power of LaTeX without requiring in-depth knowledge about LaTeX (see Document compilation). Pandoc is a Haskell library for converting from one markup format to another, and a command-line tool that uses this library. R Markdown supports a reproducible workflow for dozens of static and dynamic output formats including HTML, PDF, MS Word, Beamer, HTML5 slides, Tufte-style handouts, books, dashboards, shiny applications, scientific articles, websites, and more. So, thanks to Pandoc, Markdown it is suitable for academic writing. Markdown is a text-based markup language created by John Gruber in 2004 as a way to write in an easy-to-read format that can be converted into HTML. Processing a single Markdown file to HTML: pandoc -f markdown -t html inputfile. December 5, 2013 / Texts 0. ) Banpresto ***. The reason for the requirement is that it is all too easy for a # to end up at the beginning of a line by accident (perhaps through line wrapping). I just made sure there were "regular" higher-level headings in place so it didn't look odd. From Markdown, To Markdown. The Makefile will turn any *. The result. It is much more elegant to include proper tables that can be rendered nicely in the final document. So, open your document Module2_rmd Markdown document if you don't have it open already, and let's create a new section. Similar to HTML documents, you can enable or disable certain Markdown extensions for generating PDF documents. I tried passing commands like \LaTeX or simple tables in latex through markdown, but mathml will not work on them. Earlier today I needed to convert a spreadsheet in XLS format into a table in DokuWiki. Elle a été convertie en HTML avec la commande pandoc -s -N --toc --mathjax -c markdown-pandoc. Header levels. return pandoc. I thought you already know about the different Pandoc/Markdown table formats My answer showed that you do not need to manually format in an editor, and that you could tell Pandoc to generate Markdown tables from CSV. GitHub-like CSS for pandoc standalone HTML files (perfect for HTML5 output). If you would like a completely custom preamble, you need to specify a template file using. the indentation rules make the 2nd (and 3rd) paragraph of this text continuation paragraphs of a list item, and there's no way to put it at the top level, short of. LaTeX-produced PDFs are a lossy format for maths content. A Markdown-formatted document should be publishable as-is, as plain text, without looking like it's been marked up with tags or formatting instructions. In general, keep it simple, especially if you’re contributing to the pages that get carried over into the web help. footnote' Allow markdown extra-style footnotes. atx-header2 # This non-header doesn't begin at the first column It isn't recognized as header by markdown. (When R Markdown output format is pdf, an image will be display instead of a real table generated with latex. New module Text. We will focus the generation of reports such this document in html and pdf, although. com,1999:blog-5413546439273529984. Firstly, make sure you have installed pandoc (version >= 2. R Markdown documents are fully reproducible (they can be automatically regenerated whenever underlying R code or data changes). pdf,markdown,pandoc. Add tests for empty_paragraphs extension. 2 outputs html table as text. Exporting to Markdown is just to the "simple" markdown without definition lists, or inline HTML support. Pandoc is a command-line based program written in Haskell capable of converting multiple document formats via a JSON-based document abstraction. GitHub-like CSS for pandoc standalone HTML files (perfect for HTML5 output). Pandoc::Elements is compatible with pandoc-types 1. Table styles. Personally it would be great if pandoc supported org-ref style citations (cite:foo) with or without brackets. 24 oranges, 12, 2. there is a specific Pandoc filter pandoc-citeproc that deal very well with citations. Notice: Undefined index: HTTP_REFERER in /home/eventsand/domains/eventsandproduction. It currently uses a different Markdown processor there that only recognizes vanilla Markdown. While the default Pandoc templates used by R Markdown are designed to be flexible by allowing parameters to be specified in the YAML, users may wish to. Contents: 1. html was missing the header (which is not standard Markdown, but rather a Pandoc extension), meaning that none of the target formats included 100% of the Markdown content. The default value ( 80 ) suggests the conventional number of characters used in a line, feel free to change (e. Standard Markdown syntax does not require a blank line before a header. The result. Pandoc's template system also means that I have full control over my output—although the defaults are pretty good when I just want to. And much of the rest of the current table syntax (alignment, handling of orphan columns) follows the PHP Markdown Extra spec. e: 100% width. # # XML without inserting into a document (x is a flextable object here), as # # a consequence images are not supported since a document seems to be needed # # for that. md I also tried pandoc -s input. Technically, it is possible to create an R Markdown file without a YAML header. pandoc gets picked up automatically now, due to being in the features/ directory, but designs/ needs adding to the pandoc directory list for dmop. Right align columns in Sublime Text 3. table #my-id}), the table will be wrapped in a div with that id so it can be. The YAML header is used first to add: - a title. Node-Pandoc is simply a bridge between the Pandoc CLI (command-line interface) and NodeJS. ⋅⋅⋅You can have properly indented paragraphs within list items. Markdown has no support for tables (one of its biggest weaknesses); to create them requires embedded HTML (if that is even allowed). ‘markdown-mode’ is a major mode for GNU Emacs which provides syntax highlighting and supporting commands for editing Markdown files. And it's worth noting that this header is written in YAML. Find and replace. This can be an issue with chapter titles, which sometimes have subtitles, and go well beyond 80 characters. md in the directory into PDF slides (*. Users are advised to stick with the default multiline style, but if there is a need to change it either specify style argument when calling pander/pandoc. Pandoc::Elements is compatible with pandoc-types 1. If you haven’t heard of it, it’s a lightweight, shortened version of HTML that uses simplified tags like * ~ - # to format documents. Here's some tricks that are allowed by pandoc but not obvious at first sight. Rmd files into almost anything else. So, open your document Module2_rmd Markdown document if you don't have it open already, and let's create a new section. A simple, step-by-step example explaining exactly how to output HTML or PDF files from R. Some notable items about how formatting is used on this particular site. Since some of my posts are very long, I thought this would be a really useful thing to enable for this blog. Markdown extensions to be added or removed from the default definition or R Markdown. In the Rmd file, add a code chunk to set some pander table-layout options. Natural tables allow more fine-grained global customization but come at a performance penalty compared to extreme tables. tables featuring multiple headers or those containing cells spanning multiple rows or columns, are currently not representable in markdown format. Power Format Pack: Markdown, code blocks, lists, tables, syntax highlight & more 0. When the conversion to markdown is complete I run MainMarkdown to mash all my files into one large markdown file with an eBook header. I am now working on a project, that starting from next semester will open up to about 100 GSIs to collaboratively update a series of workbooks. Notice: Undefined index: HTTP_REFERER in /home/eventsand/domains/eventsandproduction. In Pandoc Markdown, a backslash followed by a newline generates a hard line break. R Markdown supports a reproducible workflow for dozens of static and dynamic output formats including HTML, PDF, MS Word, Beamer, HTML5 slides, Tufte-style handouts, books, dashboards, shiny applications, scientific articles, websites, and more. If the markdown formatted text is "pandoc. pandoc to get processed. Added normalize. If you are using Pandoc’s markdown (which extends John Gruber’s markdown syntax on which the GitHub Flavored Markdown is based) you can use either grid_tables:. Running the below code gave me in text citations and also played well with all the other Markdown requirements I needed: pandoc --ascii -f latex -t markdown-multiline_tables-simple_tables --atx-headers -o test. For example, markdown_strict+footnotes is strict Markdown with footnotes enabled, while markdown-footnotes-pipe_tables is pandoc's Markdown without footnotes or pipe tables. rmarkdown vs markdown R packages. md -o my_parsed_html. ⋅⋅⋅You can have properly indented paragraphs within list items. Every heading to which you want to link from other parts of the document, from the TOC, or from external sources, requires an ID. 1 source tarballThe only drawback I can think of is its less known than for example markdown, but its older (since 2001) and in my opinion better (more customisable, more extendable, more logicial and not fragmented in its syntax). The first few lines you see in the R Markdown report are known as the YAML. Pandoc has its own enhanced dialect of markdown which includes syntax for bibliographies and citations, footnotes, code blocks, tables, enhanced lists, tables of contents, embedded LaTeX math. header' Process pandoc-style header blocks. 7 Son Goku einer (Normal Color Ver. We're going to be using the YAML header to define the parameters or options used by R Markdown, R Package to render the final document. Extensions¶. 一方で、markdown-footnotes-pipe_tablesはPandoc拡張Markdownから脚注とパイプテーブル形式の表を無効にします。 哲学. Below is Markdown formatting. If you choose Markdown for its simplicity, you should not expect too much power from it, even with powerful tools like pandoc. The text in an R Markdown document is written with the Markdown syntax. The result. Basic tutorial for creating an academic article using Markdown. In his Knitr in a Knutshell, Dr. pandoc -o output. md: % A pdf file without page numbers created from pandoc markdown % sieste % June 2013 \pagenumbering{gobble} # First header etc et la commande. Technically, it is possible to create an R Markdown file without a YAML header. Pandoc-style document headers are supported; if the first three lines in the document begin with a % character, they are taken to be a document header in the form of. After removing such problematic LaTeX environments the J verb FixBaddown calls pandoc and turns baddown files into markdown files. And some document elements, such as complex tables, may not fit into pandoc's simple document model. - John Gruber. brew or the custom reference class, but installing that great piece of software is suggested if you want to convert markdown to PDF/docx/HTML or other formats. This online tool is made possible by Jonathan Hoyt’s innovative copy-excel-paste-markdown code. The first official book authored by the core R Markdown developers that provides a comprehensive and accurate reference to the R Markdown ecosystem. Exporting to Markdown is just to the "simple" markdown without definition lists, or inline HTML support. See the rmarkdown_format for additional details. In the Rmd file, add a code chunk to set some pander table-layout options. Core functionality of pander is centered around pandoc. ignore_smartypants Disable SmartyPants processing. list pandoc. byword: "All tables must begin with one or more rows of headers" PHP Markdown Extra "second line contains a mandatory separator line between the headers and the content" RDiscount Uses PHP Markdown Extra syntax. The template is compatible with pandoc 2. Pandoc is a tool to convert documents of one format to another, in this case Markdown to HTML. Pandoc will auto-gen a table of contents from the Markdown headers. The package enable creation of tables for HTML, Word and PowerPoint when using R Markdown (and not only Word). New module Text. Pandoc is the "swiss-army" knife tool of format conversions: Its core source input format supported is Markdown (including any of the major MD "dialects" such as the flavors of GitHub and PHP plus several special extensions). The file header tells the R Markdown package what type of file to create. markdown-mode is a major mode for editing Markdown-formatted text. 3 or higher is required Grokbase › Groups › R › r-help › August 2014. … There are two primary reasons for that. There are many ways to customize pandoc to fit your needs, including a template system and a powerful system for writing filters. Cleanup; TOC generation; Using Markdown Templates; Math in Pure Markdown; Convert Between the 4 Table Syntaxes in Pandoc; Repeated Footnotes Anchors and Headers Across Multiple Files; Template Snippet; YAML Metadata for. md, inputfile2. Unfortunately the Knit to PDF doesn't apply any html (md file) or css (css file) so there is no table format at all. How I create & manage my CV (or resumé) using Markdown & Pandoc. table aligns="LCR" caption="This is the **caption**" header="yes"} Fruit, Quantity, Price apples, 15, 3. I’ve also modified his code to create a version that supports column alignments as explained below. The first few lines you see in the R Markdown report are known as the YAML. Note taking with Pandoc notes with your favourite editor, chose your favourite markup language1 and view them with Chromium, Chrome or Firefox2. the empty header from. Some variants have added table support (notably Pandoc Markdown, PHP Markdown Extra, and GitHub Flavored Markdown [GFM]) but the syntax is not consistent between all of them. GitHub Flavoured Markdown; Parsedown: A parser in PHP (used e. Markdown extensions to be added or removed from the default definition or R Markdown. The template is compatible with pandoc 2. Word 2016 seems to use a default value of "1" for table headers, if there is no firstRow definition (although a default value of 0 is documented), so all tables get the first Row formatted as header. date pandoc. Add parameter for Extensions to uniqueIdent and inlineListToIdentifier (#5057). As you have discovered, --include-in-header adds text into the preamble specified in Pandoc's LaTeX template. will be replaced by the document title. … That's nice because it allows us … to format text easily with Markdown. If you are using Pandoc’s markdown (which extends John Gruber’s markdown syntax on which the GitHub Flavored Markdown is based) you can use either grid_tables:. If not available, pandoc-note also works without pandoc. It it markdown based, but without the usual annoyances. Markdown syntax is very simple and allows to add basic formatting and figures to an otherwise simple text document, without obfuscating the actual text. Any advice on how to do it will be greatly appreciated. Introduction To Markdown Using Visual Studio Code we will walk through the basics of Markdown such as creating headers, lists, tables, etc. ScholarlyMarkdown has a fixed definition of how header levels translate to the different formats. Pandoc a universal document converter. This is some text with some linebreaks Note that the two backslashes are only recognized at the end of a line or followed by a whitespace \\this happens without it. list pandoc. Only supports Anki 2. ---title: R Markdown output: html_document---This is an R Markdown document. If the source Wiki page includes code blocks, they will need to be manually converted. Pandoc is the "swiss-army" knife tool of format conversions: Its core source input format supported is Markdown (including any of the major MD "dialects" such as the flavors of GitHub and PHP plus several special extensions). template Pandoc template to use when rendering file X X X X X theme Bootswatch or Beamer theme to use for page X X toc Add a table of contents at start of document X X X X X X X toc_depth The lowest level of headings to add to table of contents X X X X X X toc_float Float the table of contents to the le# of the main content X. In Pandoc Markdown, a backslash followed by a newline generates a hard line break. md Although I can use Pandoc like this to process individual Markdown files, I want to compile a list of selected Markdown files and process them to a single file. md) of my projects welcome screen. In this tutorial, you will first learn the basics of Markdown—an easy to read and write markup syntax for plain text—as well as Pandoc, a command line tool that converts plain text into a number of beautifully formatted file types: PDF,. divquote' Allow >%class% blocks. Pandoc does require this (except, of course, at the beginning of the document). I personally am a huge fan of pandoc. The text in the document is written in Pandoc flavored Markdown. md I also tried pandoc -s input. 3, released on August 31, 2017. markdown,pandoc. Sometimes is just better to rid off of all the dynamicity of the site to achieve better performance and semplicity with just the static part, this is true if we are talking about of a simple blog like this. 2 outputs html table as text. Tables are lightly styled with lines above : and below the table and below the header with a boldface header. How I create & manage my CV (or resumé) using Markdown & Pandoc. Tables are not converted to Markdown tables. A paragraph not followed by a blank line subsumes any following paragraph, theme break, indented code block, list item, or table - these elements usually become ordinary text. Yet whereas "Original" has HTML generation in mind, pandoc is designed for multiple output formats. Examples, tips, and tricks of using R Markdown. Pandoc options 2 Syntax Becomes Make a code chunk with three back ticks followed by an r in braces. An overview of R Markdown output formats (HTML, PDF, Word, presentations, and so on) How to customize existing output formats Basic format options, e. I personally am a huge fan of pandoc. Note that there is also a Cheatsheet specific to Markdown Here if that's what you're looking for. You might be wondering what things I’m taking notes on that are important enough to warrant a whole post on how I take them. md pandoc -o document. I hope this example has shown you the process behind writing Pandoc filters. There are many differences in syntax between Blackfriday's Markdown and Pandoc's Markdown. This should work with markdown, reStructuredText, textile, LaTeX, MediaWiki markup, or any other format Pandoc supports. Definition lists without space between items, and disallow laziness Use setext headers for levels 1-2 in markdown. Tag: yaml,markdown,pandoc. 3) in the prior to GitHub css. The tex file will have an inline image (no figure environment) followed by a hard line break. Pandoc has its own enhanced dialect of markdown which includes syntax for bibliographies and citations, footnotes, code blocks, tables, enhanced lists, tables of contents, embedded LaTeX math. LaTeX-produced PDFs are a lossy format for maths content. Exactly match GitHub's identifier generating algorithm (#5057). Code : blocks are line wrapped. Scripting with pandoc. Writing ebooks with R Markdown. Navigation menu item text is formed from Pandoc's automatically generated [header identifiers] by replacing hyphens with spaces and capitalizing the first letter: Identifier Navigation item text ----- ----- header-identifiers-in-html Header identifiers in html dogs--in-my-house Dogs in my house html-s5-or-rtf Html s5 or rtf applications. It will be parsed by the Pandoc Markdown Reader before being inserted as a table into the document. Narration formatted with markdown, mixed with: Synch publish button. Headers (Setext and atx) Setext-style只有兩階也就是HTML語法裡的h1及h2 tag,-跟=的個數沒有限制. The text in an R Markdown document is written with the Markdown syntax. then wrap it in standard header/footer without any css additions or. css) CSS spécifique que nous avons réalisée et qui est plutôt orientée impression. Markdown also works throughout our project management system if you disable the WYSWIYG. The table renders fine when I place the HTML into a tool like MarkdownPad. The first is the YAML front matter that contains the documents meta information and rendering options. Pandoc does require this (except, of course, at the beginning of the document). All four kinds of pandoc tables are work. The first official book authored by the core R Markdown developers that provides a comprehensive and accurate reference to the R Markdown ecosystem. See , below, for a list of extensions and their names. Then I wrote DPP to embed diagrams in Markdown documents. For more details on the nuances of the Pandox syntax, then take a look at the "Pandoc's markdown" section on pandoc's README. Over time, many Markdown implementations have appeared. The markdown file generated by knitr is then processed by pandoc which is responsible for creating the finished format. All you need is this pandoc-note script, the Pandoc3 format converter, an editor of your choice and Chromium, Chrome or Firefox as live previewer. Since pander aims at rendering R objects into Pandoc's markdown all four (multiline, simple, grid, rmarkdown) of Pandoc's formats are supported. This is a really quick practical guide to using Markdown without all the complicated advanced syntax only. 2 outputs html table as text. In contrast to most existing tools for converting Markdown to HTML, pandoc has a modular design: it consists of a set of readers, which parse text in a given format and produce a native representation of the document, and a set of writers, which convert this native representation into a target format. Previously the parser tried to be efficient – if no end double quote was found, it would. So, for example, markdown_strict+footnotes+definition_lists is strict Markdown with footnotes and definition lists enabled, and markdown-pipe_tables+hard_line_breaks is pandoc’s Markdown without pipe tables and with hard line breaks. December 5, 2013 / Texts 0. Fix parsing of tables without headers in Pandoc Markdown format. Markdownは文書を書きやすいように設計され、さらに重要なこととして、文書を読みやすいように設計されています。. Hi, I am author of flextable. Narration formatted with markdown, mixed with: Synch publish button. Latex’s syntax for math editing. ipynb notebook document file into various static formats. For more complete info, see John Gruber's original spec and the Github-flavored Markdown info page. I usually place initializing code chunks like this at the top of a script. Then I compared them in the table above. Caveats: The new headers are indented, unlike those generated directly via markdown, and they don't show up in the table of contents. bookdown: Authoring Books and Technical Documents with R Markdown - Free download as PDF File (. When using kable() as a top-level expression, you do not need to explicitly print() it due to R's automatic implicit printing. Lots of ideas borrowed from Karl Browman's post. ‘markdown-mode’ is a major mode for GNU Emacs which provides syntax highlighting and supporting commands for editing Markdown files. md -o my_parsed_html. R Markdown documents are fully reproducible (they can be automatically regenerated whenever underlying R code or data changes). pdf document. They are an easy way of adding tables to your email -- a task that would otherwise require copy-pasting from another application. Lots of details are given here. Extension: blank_before_header. Furthermore, you can even convert markdown to Tex, which comes in handy for journal submission. 2 outputs html table as text. brew or the custom reference class, but installing that great piece of software is suggested if you want to convert markdown to PDF/docx/HTML or other formats. The quality of the result depends on the quality of both successive conversions. Personally it would be great if pandoc supported org-ref style citations (cite:foo) with or without brackets. Currently, nbconvert is provided as a command line tool, run as a script using IPython. table class will be processed. Exporting to Markdown is just to the "simple" markdown without definition lists, or inline HTML support. Updated 2018-07-17. Here’s some tricks that are allowed by pandoc but not obvious at first sight. Moodle uses PHP Markdown. definitionlist Allow definition lists. According to the documentation for Markdown Extra, MultiMarkdown, and presumably, other extensions based on PHP Markdown Extra, tables without headers aren't possible, and you would have to write such a table in raw HTML as in vanilla Markdown. function test() {console. The library includes separate modules for each input and output format, so adding a new input or output format just requires adding a new module. When you are using kable(), if you don't specify format, by default it will generate a markdown table and let pandoc handle the conversion from markdown to HTML/PDF. So what you need to do is modify the Pandoc LaTeX template. A 2nd problem arose, in that, pandoc's markdown does not support pipe_tables by default. Karl Broman introduces: kable, pander, and xtable and many useRs like the first two:. I personally am a huge fan of pandoc. The tables for format = 'markdown' also work for Pandoc when the pipe_tables extension is enabled (this is the default behavior for Pandoc >= 1. In Pandoc Markdown, a backslash followed by a newline generates a hard line break. There are a few ways to do what you are trying to do. Skihelm - matt glacier 19,adidas Tastigo 19 Short 255 Größe S,Dragon Ball Z bwfc Goku Milch Teil.


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# First Coq Coding Sprint, June 22-25 2015 Sophia-Antipolis

This page collects useful infos for the participants to the first Coq Coding Sprint

## What is a Coding Sprint?

A coding sprint is an event that brings together the core developers of Coq and people willing to understand, improve or extend the system.

## Location

The coding sprint will take place at the Inria Center in Sophia-Antipolis (how to reach the Inria center, accommodation infos).

## Program

Tentative schedule, Slides for the introduction

## Registration

For organization purposes we require the participants to register (free of charge) by following these two steps:

1. subscribe to the coordination mailing list
2. post a message with subject REGISTER. In case you already have an project in mind, please include a short description of it in the registration email.

The mailing list is also the preferred channel to contact the organizers. Subscription is required in order to post.

## Beach on Wednesday 24

Meeting point 17:00 in front of Inria or 18:00 at the beach.

Itinerary

Meeting point 20:00 if you want to join the group for dinner.

### Quick list of dinner options

(pick what you prefer and build your dinner group around you)

## List of participants

1. Yves Bertot
2. Pierre Boutillier
3. Maxime Dénès
4. Hugo Herbelin
5. Matthieu Sozeau
6. Enrico Tassi
7. Bruno Barras
8. Benjamin Gregoire
9. Pierre Letouzey
10. Jaap Boender
11. Arthur Charguéraud
12. Nicolas Magaud
13. Gabriel Scherer
14. Jason Gross
15. Assia Mahboubi
16. Arnaud Spiwack
17. Pierre-Marie Pédrot
18. Laurence Rideau
19. Jacques-Henri Jourdan
20. Reynald Affeldt
21. Guilhem Jaber
22. Jasmin Blanchette
23. Cyril Cohen
24. Nico Lehmann
25. Emilio J. Gallego Arias
26. Thomas Sibut-Pinote
27. Amin Timany
28. Thibault Gauthier
29. Théo Zimmermann (+)
30. Lionel Rieg (+)
31. Cyprien Mangin (+)
32. Abhishek Anand (+)
33. Matej Kosik (+)
34. Anders Mörtberg (+)
35. Alexander Faithfull (+)
36. Jesper Bengtson (+)
37. Guillaume Cano (+)
38. Frederic Chyzak
39. Qingguo Xu

(+) Late subscription (tradition says you pay a round at the pub...)

## Bug squashing

A list of relatively simple bugs, to kill the time

Also, bug triaging is very welcome (check if a bug is still valid, add extra info, close solved bugs...).

## "Little" projects

• coqide:
1. Make the goal window display all goals, not only the focused one. Consider using a notebook widget to let the user look at any goal by changing page. Think about creative uses for the notebook page labels. Requires GTK skills.
2. Add a "quick compile" button, as in coqc -quick. The STM can also "dump" the current state as a .vio file, but there is no protocol message for requiring such service.
3. Make coqide silently kill coqtop and save the current buffer position when too many tabs are opened and restart coqtop when the user re-opens an old tab. (see 4074)
4. Remove use of threads in the coqide back end: use CPS+Unix.select to code a cooperative threads library (in the LWT style), see tentative patch by PMP.
• tooling:
1. coqobjinfo (like ocamlobjinfo) reusing some code from votour/coqchk to get infos about a .vo or .vio file: modules/lemmas included, axioms, ... This is turn could be used to build other tools to: extract the set of assumptions associated with a final theorems, locate the places of uses of a given definition, (in the future) optimize the recompilation process by knowing which parts need to be recompiled following a change in one given definition.
2. make it possible to hide all support files (e.g. .glob files) to make directory listing and file selection/auto-completion operation simpler. (comment: very much in the spirit of what .coq-native/ does for native_compute files). One could also say that a .vo file is a directory, that the segments in which the .vo file are organized are files with standard names in these directories and that all extra metadata are again files in such directory. E.g. foo.vo/{lib,opaque,glob}. This is also compatible with Makefiles, since it is possible to target a single components.
• tactics
1. CUPS like syntax for selecting a set of goals for tactic application. I.e. generalize "all:" to "1,2-5:", see also 1805.
• ci.inria.fr
1. Prepare a job (to be copied, a sort of template) that one can easily use to compile a personal Coq branch (take from github) and a list of other git repos (like some entries from the coq-contribs).
• Win
1. test the Win64 installer on a Win64 machine
• OSX
1. try to make the procedure of building the .app reproducible (an SDK, or a scipt)
2. see if an opam root (compressed, to be unpacked in /opt/coq\$V/opam/ on the fly) can be integrated in the .app bundle and have the bundled CoqIDE use that coqtop
• opam
1. test coq:shell especially under OSX

## Brainstorming ("harder" projects, to be considered carefully)

• improving Search:

1. finding theorems that fit a pattern thanks to type classes, canonical structures, or modulo iota-reduction, or delta steps of a set of registered constants (see also #3904)
2. Invent a "search" that works for tactics: search the patterns used in the tactic, or use patterns given by the user. (related work)
3. Sort search result according to a priority heuristic to display more relevant results first.
• tools:

1. coq_makefile: use a real template engine to generate the Makefile, instead of playing with OCaml strings; alternatively make coq_makefile just generate a Makefile.conf snippet with the user setting and copy in the current directory a standard Makefile that uses conditionals at run time (not at generation time as it is done now). In both cases the Makefile should be easier to read from the sources of coq_makefile, now it is really hard to do so.
• type inference, unification:

1. Print canonical structures inference failures in error messages. E.g. "typing error... + during type inference this CS inference failed"
2. Add proper categories to unification variables (goals, typeclass constraints, implicits that should be solved...)
3. Reimplement and merge typeclasses eauto, auto and eauto using the new tactic engine.
4. Let the user tell TI when the expected type should be propagated down via an Argument directive. E.g. with Arguments cons {A} | x xs type inference should unify A (probably an implicit) with the A in the expected type before processing x and xs. If the expected type is list Q and x is a nat, then N->Q coercion could be inserted. If we wait, we may infer that the list is list nat and there is not coercion to list Q.
• bench system:

1. plug decent graphs into ci.inria.fr/coq
2. fix coqc -quick -time Bug 3934
• developers manual:

2. Write down the policies (a real document): how to submit code to Coq, how to submit a contrib, how opam packages should be written...
• kernel

1. Make it possible for the kernel to accept an a priori unsound definition (not guarded, not universe consistent, not strictly positive) when the definition is prefixed by some command. This must be taken account by Print Assumptions with assumptions like foo is total.
2. Harden the kernel interface: move from arrays to an abstract type at least.
• tactics:

1. decouple the prelude from the tactics
2. Coding the tactics of the logic.ml file in the new proof engine. These were the primitive tactics of the old proof engine and are currently implemented using a compatibility layer which, in particular, makes the Info command unaware of their semantics.
3. Implement a "debug" trace for tactics. The Info command gives a trace of the tactics which were effectively applied. In order to debug scripts, it may be useful to also have a trace of all the tactics which were attempted.
4. Port LtacProf to Coq 8.5, possibly hooking into the Info infrastructure.
• declarative proof mode

1. More robust implementation of the declarative proof mode. The declarative mode, because it's older, doesn't really take advantage of the disciplined focus API of the new proof engine and re-implements its features in a fragile way. To move forward, the code must be cleaned up and use the modern API.
• Notation:

1. control notation/implicits/coercions display on a sub term
• stdlib:

1. uniform names/notations see Bug 4110
2. document the axiom used in each file/file-group
• Evar instantiation failure explanation: given an evar defined in some context, and given a term with which the evar fails to unify, report to the user the list of variables that occur in the term but that do not belong to the context in which the evar was defined.

• Computation of the dependency graph

The goal is to build an OCaml data structure representing the global dependency graph (given a set of compiled files):

• each node is labelled with the fully qualified path of a definition; the node carries a flag indicating whether the proof is transparent (i.e. Defined vs Qed).
• the node associated with "foo" has two sets of outgoing edges: one for describing the definitions that are required for typechecking the type of "foo", and one for describing the definitions that are required for typechecking the body of "foo" (body of the definition, or the proof term).
• A lightweight abstraction mechanism

Currently, the only way to have a real abstraction layer is to use module signatures, which are very heavy in practice, as they require copy-pasting statements. It would be nice if the same result could be achieve through a simple top-level command, "Abstract foo bar." which would ensure that all the definitions mentioned have their definition made really opaque, as if the definitions/proofs where enclosed in a module signature.

• Environments: a powerful replacement for sections

The idea is to introduce environments, which solve the problem of closing/reopening a section with similar variables and implicit types, and which generalizes the notion of notation scope and hint database. An "environment" consists of a set of declaration, among: context variables declaration, implicit types declaration, eauto hint declaration, local notation declaration, coercion declaration, instance declaration. (Note that dependencies are possible, i.e. an implicit type or a hint or a notation can be associated with a context variable.) An "environment" can be named, and can be opened in a section. It can be built as the union of existing environments (or by removing declarations from existing environments). Environments are functional (i.e. they are not extended in place), even though a convenient syntax can be provided for extending an environment and immediately rebinding it with the same name, so as to locally give the illusion that it is augmented in place. Having functional environments solves the modularity issue that is currently associated with scopes / hint / instances being global.

• Speeding up recompilation in a project

The idea is to make it possible to recompile the definitions located in all the dependencies of a given file as fast as possible, by skipping all proofs in the dependencies, and avoiding the space blow-up currently affecting vio files.

• "The command "coqlighten foo.v" generates "foo.light.v", which is the same as foo.v except that all lemmas whose proof ends on a Qed are replaced with a corresponding axiom. (coqlighten can probably be implemented using sed with the right regular expression). This file is typically compiled using "coqc" as "foo.light.vo".

• "coqc -light bar.v" treats "Require Import foo" exactly as if it were "Require Import foo.light", and it produces as output the file "bar.vo.light" (instead of "bar.vo").

• "coqdep foo.v" (where "foo.v" depends on "bar.v") produces dependencies using an extra level of indirection that is useful for the end-user (read further), as follows:

• foo.vo: foo.vo.requires
• foo.vo.requires: bar.vo
• foo.vo.light: foo.vo.light.requires
• foo.vo.light.requires: bar.light.vo

Note that we have "foo.light.vo: foo.light.v" following the standard compilation rule based on "coqc", and we also have "foo.light.v: foo.v" following the build rule based on "coqlighten".

• In CoqIDE, add a shortcut that, when the current file is "foo.v", runs the command "make foo.vo.light.requires", and then (optionnaly) reloads the current file up to current location in this file. This allows making a change in another file "bar.v", and getting back to an up-to-date state in "foo.v" with minimal recompilation effort.

• If parsing takes significant time, it is possible to dump the content of the parsed tree in binary format, in e.g. "foo.light.ast". This assumes, though, that the user will be responsible for doing a clean of those files if he changes the scopes or the set of notation being used.

• (bonus) HTML5 interface for Coq developments The idea is to make sure that all the tools are ready to allow for the development of an alternative to CoqIDE, which would allow for:

• customizable display for domain-specific uses of Coq (e.g. CFML).
• display of latex-style mathematical formula using mathjax.
• working with Coq online without any local installation, in case a remote server is used for compiling scripts.
• integration in the display of links for looking up definitions.

What's needed:

• a basic http server that runs coqtop, and (preferably) that is able to do a little bit of caching to avoid the transmition of fule files on every change.
• a way for the server to obtain from coqtop structured AST (instead of plain strings), so as to be able to render structured display.
• a Coq plugin to be able to register latex notation with term constructs (such a plugin would also be useful to generate readable versions of formal definitions, e.g. for documentation purposes)."
• (bonus) Development benchmark for Coq developers

The idea is to gather a few real, modern Coq developments, and use them for the during-the-day testing of changes to the code base of Coq.

• Select a number of developments provided by volunteers Coq power users, who are available to help in case the developers of Coq cannot easily figure out why a proof has been broken by their changes.
• For each, ask the authors to maintain a little script to describe which lemmas should be turned into axioms (to save compilation time), keeping only a representative subset of the lemmas in the developments. Typically, it would suffice to provide a list of lemmas to keep, e.g. in JSON format:
[ { file : "foo.v",
keep : [ "lemma_x", "lemma_y" \], keep_sections : [ "Part1" ] },
{ file : "bar.v", keep_all : "true" } ] // keep_all could be implicit.

The goal is to test a maximal number of aspects in less than 1 minute of compilation time per development. (If needed, it is also possible to exclude some files entirely.)

• The code can be pulled (on carefully-chosen commit points) form the git repository of the authors, then the filter on proofs is applied. Optionnaly, these generated files can be commited in a git used by coq developers, but this might not be necessary if the process is fast enough.
• It might be useful to also keep track of little patches that may need to be applied to the development, in order to cope with non-backward compatible changes. Such patches could be commited in the git of the Coq developers.
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# What is the link between free energy and lagrangian?

Free energy is a generalization of energy when the system exchanges heat with the environment. Energy, in its turn, can be extracted from lagrangian under the symmetry of time $(\frac{\partial L}{\partial t}=0)$. However, I can't find any sources that links the free energy directly from lagrangian. Is there any way to do that? If it is, what symmetry is it based on?

• If you like this Phys.SE question, you may also enjoy reading this Phys.SE post. – Qmechanic Jun 16 '14 at 16:12


text:
Smirnov {stats} R Documentation

## Distribution of the Smirnov Statistic

### Description

Distribution function, quantile function and random generation for the distribution of the Smirnov statistic.

### Usage

psmirnov(q, sizes, z = NULL, two.sided = TRUE,
exact = TRUE, simulate = FALSE, B = 2000,
lower.tail = TRUE, log.p = FALSE)
qsmirnov(p, sizes, z = NULL, two.sided = TRUE,
exact = TRUE, simulate = FALSE, B = 2000)
rsmirnov(n, sizes, z = NULL, two.sided = TRUE)

### Arguments

 q a numeric vector of quantiles. p a numeric vector of probabilities. sizes an integer vector of length two giving the sample sizes. z a numeric vector of the pooled data values in both samples when the exact conditional distribution of the Smirnov statistic given the data shall be computed. two.sided a logical indicating whether absolute (TRUE) or raw differences of frequencies define the test statistic. exact NULL or a logical indicating whether the exact (conditional on the pooled data values in z) distribution or the asymptotic distribution should be used. simulate a logical indicating whether to compute the distribution function by Monte Carlo simulation. B an integer specifying the number of replicates used in the Monte Carlo test. lower.tail a logical, if TRUE (default), probabilities are P[D < q], otherwise, P[D \ge q]. log.p a logical, if TRUE (default), probabilities are given as log-probabilities. n an integer giving number of observations.

### Details

For samples x and y with respective sizes n_x and n_y and empirical cumulative distribution functions F_{x,n_x} and F_{y,n_y}, the Smirnov statistic is

D = \sup_c | F_{x,n_x}(c) - F_{y,n_y}(c) |

in the two-sided case and

D = \sup_c ( F_{x,n_x}(c) - F_{y,n_y}(c) )

otherwise.

These statistics are used in the Smirnov test of the null that x and y were drawn from the same distribution, see ks.test.

If the underlying common distribution function F is continuous, the distribution of the test statistics does not depend on F, and has a simple asymptotic approximation. For arbitrary F, one can compute the conditional distribution given the pooled data values z of x and y, either exactly (feasible provided that the product n_x n_y of the sample sizes is “small enough”) or approximately Monte Carlo simulation. If the pooled data values z are not specified, a pooled sample without ties is assumed.

### Value

psmirnov gives the distribution function, qsmirnov gives the quantile function, and rsmirnov generates random deviates.

ks.test for references on the algorithms used for computing exact distributions.


text:
Started in 1985 Semimonthly
ISSN 1005-0302
CN 21-1315/TG
Impact factor:6.155

The journal has been awarded the excellent periodical in China, and its articles are covered by SCI, EI, CA, SA, JST, RJ, CSA, MA, EMA, AIA etc., PASCAL web. ISI web of Science,SCOPUS.

Current Issue
 15 March 2020, Volume 41 Issue 0 Previous Issue    Next Issue
Research Article
 Select Evolution of microstructure and tensile properties of cold-drawn hyper-eutectoid steel wires during post-deformation annealing Majid Jafari, Chan-Woo Bang, Jong-Chan Han, Kyeong-Min Kim, Seon-Hyeong Na, Chan-Gyung Park, Byeong-Joo Lee J. Mater. Sci. Technol., 2020, 41 (0): 1-11.  DOI: 10.1016/j.jmst.2019.08.054 Manufacturing temperatures of severely cold-drawn hyper-eutectoid steel wires are sufficiently high to influence the mobility of dislocations and alloy elements, thereby affecting the materials’ mechanical properties. Herein, we describe the evolution of microstructure and tensile strength of the as-drawn 3.45 GPa steel wire during post-deformation annealing for 30 min at 150-450 °C. Annealing at 150 °C raised the strength to 3.77 GPa by age-hardening through activation of dislocations pinning by carbon, while further temperature rising up to 450 °C caused a severe loss of strength. It was proved that annealing at 300 and 450 °C destabilizes the lamellar microstructure, promoting the formation of carbon-deficient (Fe,Mn,Cr)3C-type cementite particles with preferentially rounded and partially faceted hetero-interfaces. Annealing at 450 °C yielded the accumulation of Mn and Cr at the ferrite/particle interfaces, and their concentrations at the interfaces were dependent on the interface structure; i.e., lower concentrations at rounded interfaces (formed through capillarity-driven coarsening of the spheroidized cementite), and higher concentrations at faceted interfaces (that are initially existing in the as-drawn state). Our proof-of-principle observations, supported by thermodynamic calculations and kinetic assessments, provide a pathway for understanding the changes in microstructural and tensile properties during manufacturing of the hyper-eutectoid steel wires.
 Select Improvement in varistor properties of CaCu3Ti4O12 ceramics by chromium addition Edson Cezar Grzebielucka, João Frederico Haas Leandro Monteiro, Eder Carlos Ferreira de Souza, Christiane Philippini Ferreira Borges, André Vitor Chaves de Andrade, Eloísa Cordoncillo, Héctor Beltrán-Mir, Sandra Regina Masetto Antunes J. Mater. Sci. Technol., 2020, 41 (0): 12-20.  DOI: 10.1016/j.jmst.2019.08.055 The effect of chromium addition on the structure and electrical properties of CaCu3Ti4O12 is studied. Compositions based on the formula CaCu3Ti4-xCrxO12-δ (x = 0, 0.025, 0.050 and 0.075 mol%) are prepared by solid-state reaction. Pellets sintered at 1070 °C for 12 h are characterised by X-ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and impedance spectroscopy. Current density-electric field, dielectric loss and permittivity measurements are also carried out. Rietveld refinement showed the substitution of Cr(III) on the Ti(IV) site, with the maximum substitution for x = 0.025 mol%. The generation of electrical defects in the grain boundary region by chromium doping is responsible for increasing the electric breakdown field strength and nonlinearity coefficient at room temperature from 1723 V/cm and 5.29 for x = 0 mol% to 3431 V/cm and 8.16 for x = 0.025 mol%. This composition shows the greatest improvement in ceramic varistor parameters.
Orginal Article
 Select Comparisons of corrosion behaviour for X65 and low Cr steels in high pressure CO2-saturated brine Yong Hua, Sikiru Mohammed, Richard Barker, Anne Neville J. Mater. Sci. Technol., 2020, 41 (0): 21-32.  DOI: 10.1016/j.jmst.2019.08.050 Appropriate materials for injection pipelines and tubing for carbon dioxide geologic storage is fundamental to ensure asset integrity and save cost. This paper evaluates the corrosion behaviour of X65, 1Cr, 3Cr and 5Cr, which have the potential to be injection pipeline/tubing materials. The influence of steel Cr content on the general and localised corrosion behaviour was investigated at time periods from 6 to 192 h at 60 °C and 100 bar. The evolution, morphology and chemistry of corrosion products on the surface of each material were evaluated using a combination of scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction and related to their overall corrosion protection. Results indicate that prior to the formation of protective films on the steel surfaces, the resistance of the materials to corrosion increase with increasing Cr content (Corrosion resistance: X65 < 1Cr<3Cr<5Cr). However, as corrosion products evolve, the protection afforded to the different steels significantly varies and decreases with increasing Cr content. × 65 becomes the material with the lowest general corrosion rate by the end of the 192 h experiments and 5Cr exhibits the highest corrosion rate (ranking of corrosion resistance: X65 > 1Cr>3Cr>5Cr). In terms of the corrosion products on X65, both inner amorphous and outer crystalline corrosion layers consist of FeCO3. For the Cr-containing steels, the outer layer also comprises FeCO3, but the inner layer is enriched with Cr, and is predominantly amorphous Cr(OH)3. The extent of localised corrosion (determined using surface profilometry) is noticeably less for X65 compared to the Cr-containing steels. The paper raises questions about the benefits that low Cr steels offer towards extending component design life compared to carbon steel under the test conditions considered here.
Research Article
 Select Corrosion resistance of self-cleaning silane/polypropylene composite coatings on magnesium alloy AZ31 Zhao-Qi Zhang, Rong-Chang Zeng, Cun-Guo Lin, Li Wang, Xiao-Bo Chen, Dong-Chu Chen J. Mater. Sci. Technol., 2020, 41 (0): 43-55.  DOI: 10.1016/j.jmst.2019.08.056 Magnesium (Mg) and its alloys have been widely used in a variety of industrial fields, however, the high corrosion rate and surface contamination restrict their applications. In this study, a corrosion-resistant polymer coating with self-cleaning properties on Mg alloy AZ31 was successfully fabricated via a pretreatment of amino-silane (poly(3-aminopropyl)trimethoxysilane, PAPTMS) and subsequently covered with a polypropylene (PP) film. Surface morphology and chemical compositions were examined using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Fourier transform infrared spectrophotometry (FT-IR) and X-ray photoelectron spectroscopy (XPS) as well. Contact angle was measured to determine hydrophobicity of the composite coatings. Water permeability of the coatings was evaluated through electrochemical impedance spectroscopy (EIS). Corrosion resistance of the coating was investigated using electrochemical and hydrogen evolution tests. Results indicated that PAPTMS/PP coatings possessed a micrometer-scaled porous spherical microstructure, and super-hydrophobicity with high water contact angle (162 ± 3.4°) and low sliding angle (5 ± 0.6°) due to the low surface energy (10.38 mJ/m2). Moreover, the coating exhibited a smaller water diffusion coefficient (8.12 × 10-10 cm2/s) and water uptake volume fraction (24.5 %), demonstrating low water permeability and good physical barrier performance. As a result, the corrosion current density of PAPTMS/PP coating exhibited approximately three orders of magnitude lower than that of the AZ31 substrate, suggesting excellent corrosion resistance. Finally, corrosion-resistant mechanism of the hybrid coating was proposed.
 Select In vitro insights into the role of copper ions released from selective laser melted CoCrW-xCu alloys in the potential attenuation of inflammation and osteoclastogenesis Yanjin Lu, Xiongcheng Xu, Chunguang Yang, Ling Ren, Kai Luo, Ke Yang, Jinxin Lin J. Mater. Sci. Technol., 2020, 41 (0): 56-67.  DOI: 10.1016/j.jmst.2019.09.016 In this study, the CoCrW-xCu alloys (x = 2, 3 and 4 wt%) were fabricated using selective laser melting (abbreviated as Co-2Cu, Co-3Cu and Co-4Cu) with the purpose of reducing the inflammation responses and the activity of osteoclast. The metal ions releasing test showed that when the Cu content was less than 4 wt%, the releasing amount of Co and Cr ions was very small; however, when 4 wt% Cu was added in the CoCrW based alloy, the quantity of Co ions was significantly elevated with respect to the other groups due to the segregation of precipitates in the matrix; the Cu2+ ion quantity of the Co-2Cu, Co-3Cu and Co-4Cu alloys were 0.05, 0.09 and 0.27 μg/(L cm2) after 7 d immersion, respectively; the RT-qPCR and ELISA data indicated that the expression levels of the pro-inflammatory cytokines (TNF-α and IL-6) were down-regulated in the Co-3Cu and Co-4Cu groups, whereas the expression level of the anti-inflammatory cytokine (IL-10) was up-regulated in all CoCrW-xCu alloys; meanwhile, the Cu-containing CoCrW alloys significantly down-regulated the expression of the NF-κB signal pathway in a Cu content-dependent manner, and the downstream transcription factors of NF-κB signal pathway including NFATc1, TRAP and Cath-K were also down-regulated via potentially manipulating the NF-κB signal pathway. After comprehensive consideration, it is considered that the Co-3Cu alloy is a potential material for self-alleviating inflammatory responses.
 Select A novel graphene aerogel synthesized from cellulose with high performance for removing MB in water Jin Li, Qin Wang, Lei Zheng, Hongbo Liu J. Mater. Sci. Technol., 2020, 41 (0): 68-75.  DOI: 10.1016/j.jmst.2019.09.019 A novel graphene aerogel has been synthesized from cellulose by an easy way through sol-gel reaction and carbonization. In this route, it can be found the products have a high yield about 48 % and form a specific porous networks assembled by graphene flake. The product sample like CGA-2, characteristic of a specific area about 1426.11 m2/g and total pore volume about 1.02 cm3/g, exhibits a remarkable performance for removing cationic dye like methylene blue (MB) in water. Of which the maximal MB adsorption capacity can be found about 610.85 mg/g in a neutral solution and 1.2 g/g in a basic solution. Under the condition of initial MB concentration of 100 mg/L and pH of 7.0, the adsorption equilibrium can be achieved on CGA-2 in 10 min, with MB removal ratio about 99 %. In the MB adsorption on CGA-2, the isotherm fits Langmuir model with correlation coefficient of 0.9905, and the kinetics follows pseudo-second-order model with correlation coefficient of 0.9999.
Letter
 Select Effects of temperature and alloying content on the phase transformation and {10$\bar{1}$1} twinning in Zr during rolling Xinglong An, Hao Zhang, Song Ni, Xiaoqin Ou, Xiaozhou Liao, Min Song J. Mater. Sci. Technol., 2020, 41 (0): 76-80.  DOI: 10.1016/j.jmst.2019.09.022 The effects of temperature and Ti content on the deformation mechanisms of pure Zr and Zr-Ti alloys were investigated by transmission electron microscopy. The results indicate the existence of a relation between deformation-induced phase transformation from a hexagonal close-packed structure to a face-centered cubic structure and {10$\bar{1}$1} deformation twinning. That is, when one is suppressed, the other will be promoted. The phase transformation was suppressed while the {10$\bar{1}$1} compressive twinning was promoted with increasing the rolling temperature and/or Ti content. This can be attributed to the activation of basal dislocations at high temperature and the increased stacking fault energy with Ti content.
Research Article
 Select Tuning magnetic properties, thermal stability and microstructure of NdFeB magnets with diffusing Pr-Zn films Jiajie Li, Xiangyun Huang, Liangliang Zeng, Bo Ouyang, Xiaoqiang Yu, Munan Yang, Bin Yang, Rawat Rajdeep Singh, Zhenchen Zhong J. Mater. Sci. Technol., 2020, 41 (0): 81-87.  DOI: 10.1016/j.jmst.2019.09.024 Grain boundary diffusion process (GBDP) serves as a promising approach in improving magnetic properties and thermal stability of NdFeB permanent magnets. Herein, non-heavy rare earth Pr-Zn films deposited on the magnet surface using DC-magnetron sputtering system are reported. The thermal stability and coercivity enhancement mechanism of Pr-Zn GBDP magnets were investigated. Results show that the coercivity of Pr-Zn GBDP magnet increases from 963.96 kA m-1 to 1317.14 kA m-1 without any remanence reduction. Notably, the demagnetization curve of Pr-Zn GBDP magnet still remains a high squareness ratio. The temperature coefficient of coercivity and anti-demagnetization ability of Pr-Zn GBDP magnet under high temperatures are improved after GBDP treatment. The well-optimized rare earth-rich (RE-rich) grain boundary phases and high effective anisotropy field of (Nd,RE)2Fe14B magnetic hardening layers surrounding main grains are the key factors to impact the magnetic properties and thermal stability of NdFeB permanent magnets via GBDP treatment.
 Select Synthesis of unique-morphological hollow microspheres of MoS2@montmorillonite nanosheets for the enhancement of photocatalytic activity and cycle stability Peng Chen, Shilin Zeng, Yunliang Zhao, Shichang Kang, Tingting Zhang, Shaoxian Song J. Mater. Sci. Technol., 2020, 41 (0): 88-97.  DOI: 10.1016/j.jmst.2019.09.021 In this work, MoS2@montmorillonite nanosheets hollow microspheres (MoS2@MMTNS-HMS) with a novel morphology structure was successfully synthesized through loading MoS2 to the surface of MMTNS-HMS via hydrothermal method. The novel material has been characterized through the measurements of SEM, TEM, Raman spectra and UV-vis absorption spectra. The results have shown that MoS2@MMTNS-HMS emerges higher light-utilization efficiency, density of edge active sites and separation of photoelectrons, owing to its unique hollow structure, vertically-aligned MoS2 nanosheets, which greatly enhances its photocatalytic activity. Furthermore, the cycle stability of MoS2@MMTNS-HMS is much higher than that of pristine MoS2, which is attributed to that MMTNS-HMS greatly inhibits the oxidation of MoS2 during photocatalytic. MoS2@MMTNS-HMS could be a promising photocatalyst for the applications in the elimination of organic pollutants.
 Select On the texture memory effect of a cross-rolled Mg-2Zn-2Gd plate after unidirectional rolling Pengfei Zhang, Yunchang Xin, Ling Zhang, Shiwei Pan, Qing Liu J. Mater. Sci. Technol., 2020, 41 (0): 98-104.  DOI: 10.1016/j.jmst.2019.05.076 A Mg-2Zn-2Gd alloy subjected to a cross rolling and annealing often has a texture with c-axes of grains evenly distributing on a circle approximately 40° away from the normal direction (ND), which can completely remove the planar mechanical anisotropy. The texture memory effect and planar mechanical anisotropy of such a cross-rolled plate after an unidirectional rolling and subsequent annealing were systematically investigated. The results show that the circle-shaped texture is partially retained after the unidirectional rolling and annealing, with basal poles evenly distributing on an ellipse approximately 30°-40° away from the ND. This small texture difference will lead to quite different mechanical anisotropies between the two plates, namely, a quite low anisotropy of yield strength between the rolling direction (RD) and transverse direction (TD) before the unidirectional rolling, in contrast to an obvious mechanical anisotropy after unidirectional rolling. A quantitative calculation shows that tension along the RD of the plate after the unidirectional rolling will activate a much higher fraction of prismatic slip than tension along the TD. The much higher critical resolved shear stress for prismatic slip than that for basal slip or {10 $\bar{1}$ 2} twinning accounts for the much higher yield strength of TD tension than that of RD tension. The mechanisms for texture evolution during the unidirectional rolling and annealing were also discussed.
 Select Microstructure and mechanical properties of double-side friction stir welded 6082Al ultra-thick plates C. Yang, J.F. Zhang, G.N. Ma, L.H. Wu, X.M. Zhang, G.Z. He, P. Xue, D.R. Ni, B.L. Xiao, K.S. Wang, Z.Y. Ma J. Mater. Sci. Technol., 2020, 41 (0): 105-116.  DOI: 10.1016/j.jmst.2019.10.005 In the present work, 80 mm thick 6082Al alloy plates were successfully double-side welded by friction stir welding (FSW). The relationship between the microstructures and mechanical properties was built for the double-side FSW butt joint with more attention paid to the local characteristic zones. It was shown that a phenomenon of microstructural inhomogeneity existed in the nugget zone (NZ) through the thickness direction. The grain size presented an obvious gradient distribution from the top to the bottom for each single-pass weld, and the microhardness values decreased from both surfaces to the middle of the NZ. The lowest hardness zone (LHZ) exhibited a “hyperbolical”-shaped distribution extending to the middle of the NZ. Similar tensile properties were obtained in the three sliced specimens of the FSW joint, and the joint coefficient reached about 70% which achieved the same level as the conventional FSW Al alloy joints. Finite element modeling proved that the “hyperbolical”-shaped heat affected zone (HAZ) was beneficial to resisting the strain concentration in the middle layer specimen which helped to increase the tensile strength. Based on the analysis of the hardness contour map, tensile property and microstructural evolution of the joints, an Isothermal Softening Layer (ISL) model was proposed and established, which may have a helpful guidance for the optimization on the FSW of ultra-thick Al alloy plates.
 Select Sulfur-doped g-C3N4/rGO porous nanosheets for highly efficient photocatalytic degradation of refractory contaminants Yanmei Zheng, Yuanyuan Liu, Xinli Guo, Zhongtao Chen, Weijie Zhang, Yixuan Wang, Xuan Tang, Yao Zhang, Yuhong Zhao J. Mater. Sci. Technol., 2020, 41 (0): 117-126.  DOI: 10.1016/j.jmst.2019.09.018 Graphitic carbon nitride (g-C3N4, CN) has attracted increasing interests in the field of photocatalysis due to its high visible-light-response. However, its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(VI) and Rhodamine B (RhB) etc. Herein, we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide (rGO) porous nanosheet (S-CN/rGO PNs) via a supramolecular self-assembling followed by a solvothermal treatment. The as-prepared porous S-CN/rGO PNs are stable with high specific surface area ～188.5 m2g-1 and exhibit a significantly enhanced photocatalytic activity of ～17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(VI) under visible light irradiation, respectively. Typically, 50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs. The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers. The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.
 Select Structures and formation mechanisms of dislocation-induced precipitates in relation to the age-hardening responses of Al-Mg-Si alloys Y.X. Lai, W. Fan, M.J. Yin, C.L. Wu, J.H. Chen J. Mater. Sci. Technol., 2020, 41 (0): 127-138.  DOI: 10.1016/j.jmst.2019.11.001 In the slightly deformed Al-Mg-Si alloys, dislocation-induced precipitates are frequently observed, and they usually line up, forming sophisticated precipitation microstructures. Using atomic-resolution electron microscopy in association with hardness measurements, we systematically investigated these precipitates in relation to the age-hardening responses of the alloys. Our study reveals that the majority of dislocation-induced complex precipitates are actually short-range ordered while long-range disordered polycrystalline precipitates and multiphase composite precipitates, including polycrystalline U2 precipitates, B'/U2, B'-2/U2, B'/B'-2/U2 and β'/U2 composite precipitates. It is suggested that the formation of these complex precipitates is mainly owing to a high nucleation rate and rapid growth of different precipitate phases parallel to the associated dislocation lines. Since dislocation-induced precipitates consume more Mg than Si from the matrix and have a high formation kinetics, they will have different impacts on the matrix precipitation in different types of Al-Mg-Si alloys. Our results further demonstrate that for the “normally-β"-hardened” alloy, their formation leads to a coarser precipitate microstructure in the matrix, whereas for the “normally-β'-hardened” alloy, their formation reverses the precipitation pathway in the matrix, resulting in a reduced age-hardening potential of the former alloy and an improved age-hardening potential of the latter alloy.
 Select Simultaneously enhanced strength and ductility of 6xxx Al alloys via manipulating meso-scale and nano-scale structures guided with phase equilibrium Qiang Lu, Kai Li, Haonan Chen, Mingjun Yang, Xinyue Lan, Tong Yang, Shuhong Liu, Min Song, Lingfei Cao, Yong Du J. Mater. Sci. Technol., 2020, 41 (0): 139-148.  DOI: 10.1016/j.jmst.2019.09.029 Excellent comprehensive mechanical properties including good formability, high strength and high ductility are prior demands for Al-Mg-Si-Cu alloys. This study utilizes calculation of phase diagram (CALPHAD) to simplify the alloy design and meet these demands. Specifically, CALPHAD was used to finely tune the Mg/Si atomic ratio in solid solution and accurately control the type and content of second phases, especially to avoid the formation of the harmful constituent phase β-AlFeSi. Constituents and dispersoids of only α-AlFeMnSi phase were found in the alloy prepared. An optimized microstructure with fine grains, micro scale constituents, densely distributed submicron scale dispersoids and extremely dense nano precipitates provides effective impediment to dislocation gliding and induces transgranular fracture. Therefore, the designed alloy has better comprehensive mechanical properties than other 6xxx series aluminum alloys, including excellent formability, strength and ductility. The low T4P strength of 149 MPa as well as the high elongation of 26.1% implies the alloy's applicability to automobile body panel forming. The yield strength was rapidly improved from 149 MPa to 277 MPa during the paint bake ageing, because the number density of precipitates is twice as high as that of some other 6xxx alloys. Meanwhile, the elongation was kept at a high level of 20.0%.
 Select Precipitation mechanism and microstructural evolution of Al2O3/ZrO2(CeO2) solid solution powders consolidated by spark plasma sintering Wanjun Yu, Yongting Zheng, Yongdong Yu J. Mater. Sci. Technol., 2020, 41 (0): 149-158.  DOI: 10.1016/j.jmst.2019.09.028 It is difficult to synthesize Al2O3/ZrO2 solid solution because of its low solubility under equilibrium solidification conditions. In this work, a new combustion synthesis combined with water atomization (CS-WA) method was developed to prepare supersaturated Al2O3/ZrO2(CeO2) solid solution powders. The ultra-high cooling rate supplied by CS-WA greatly extends solid solubility of Al2O3 in ZrO2. The precipitation mechanism of solid solution was investigated by systematic heat treatments. The initial temperature of the metastable phase decomposed into Al2O3 and ZrO2 is 1050 °C, and it could be completely precipitated at 1400 °C in 0.5 h. The precipitated ZrO2 particles were uniformly dispersed in Al2O3 matrix and grew into submicron scale at annealing temperature of 1450 °C. Subsequently, together with detailed microstructure, phase composition, as well as mechanical properties were collaboratively outlined to discuss spark plasma sintering (SPS) behavior. The solid solution precipitated Al2O3 matrix and ZrO2 particles during the SPS process. Partial ZrO2 particles were uniformly distributed within Al2O3 matrix, while the residuary ZrO2 located at the grain boundaries and formed special transgranular/intergranular structure. The average size of nanoscale transgranular ZrO2 particles was only ～11.5 nm. The compact ZrO2 toughened Al2O3 nano ceramic (N-ZTA) exhibits excellent mechanical properties. This work provides a guidance to produce nanostructured ZTA with high performance.
 Select Preparation of sulfur hydrophobized plasmonic photocatalyst towards durable superhydrophobic coating material Emese Lantos, László Mérai, Ágota Deák, Juan Gómez-Pérez, Dániel Sebők, Imre Dékány, Zoltán Kónya, László Janovák J. Mater. Sci. Technol., 2020, 41 (0): 159-167.  DOI: 10.1016/j.jmst.2019.04.046 The widely used photocatalytic self-cleaning coating materials are often made of polymers and polymer based composites, where the photocatalyst immobilization occurs with macromolecules. However, these organic polymers are often unstable under exposure to UV irradiation and easily degraded by reactive radicals produced in the photocatalytic reaction. In order to solve this problem, in this paper, we present the facile preparation of a multifunctional coating with dual superhydrophobic and photocatalytic properties, where the fixation and the hydrophobization of the plasmonic Ag-TiO2 photocatalyst particles with visible light activity was performed with non-water soluble sulfur, which is a cheap and easily available material. The resulted novel nanocomposite with rough and nano-tructured surface roughness (1.25-2.45 nm determined by small-angle X-ray scattering) has sufficient low surface energy (3.3 mJ/m2) for superhydrophobic (θ = 151.1°) properties. Moreover, in contrast of the organic and expensive fluoropolymer based composites, this non-wetting nature was durable, because the measured θ was higher than 150° during the long- term LED (λmax = 405 nm) light irradiation.
 Select Ultrafast synthesis of gold nanoparticles on cellulose nanocrystals via microwave irradiation and their dyes-degradation catalytic activity Madhusudhan Alle, Seung-Hwan Lee, Jin-Chul Kim J. Mater. Sci. Technol., 2020, 41 (0): 168-177.  DOI: 10.1016/j.jmst.2019.11.003 This study represents a well-dispersed gold nanoparticles (AuNPs) synthesis process via cellulose nanocrystals (CNC) which acts as both reducing and supporting agent. The synthesis process was ultrafast and completed in a few seconds using microwave irradiation. The entire synthesis process was cost-effective, sustainable and eco-friendly. The synthesized (AuNPs/CNC) nanocomposite was investigated by transmission electron microscopy, selected area electron diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, X-ray diffraction, and UV-vis spectroscopy. The obtained AuNPs were well accumulated on the CNC surface and had a uniform spherical shape with an average diameter of 8 ± 5.3 nm. The diameter of AuNPs could be altered by tuning the concentration of CNC suspension. The synthesized AuNPs/CNC nanocomposite film exhibited excellent degradation properties against various organic dyes, namely, Allura red, Congo red, Rhodamine B and Amaranth. The ultrafast degradation reactions followed pseudo first order kinetics. In the catalytic degradation reaction, AuNPs/CNC was transmitting electrons from a donor (NaBH4) to an acceptor (a dye).
 Select Microstructure and mechanical properties of Al-Mg-Si alloy fabricated by a short process based on sub-rapid solidification Ze-Tian Liu, Bing-Yu Wang, Cheng Wang, Min Zha, Guo-Jun Liu, Zhi-Zheng Yang, Jin-Guo Wang, Jie-Hua Li, Hui-Yuan Wang J. Mater. Sci. Technol., 2020, 41 (0): 178-186.  DOI: 10.1016/j.jmst.2019.08.053 Al-Mg-Si (AA6xxx) series alloys have been used widely in automotive industry for lightweight purpose. This work focuses on developing a short process for manufacturing Al-0.5Mg-1.3Si (wt.%) alloy sheets with good mechanical properties. Hereinto, a preparation route without homogenization was proposed on the basis of sub-rapid solidification (SRS) technique. The sample under SRS has fine microstructure and higher average partition coefficients of solute atoms, leading to weaker microsegregation owing to the higher cooling rate (160 °C/s) than conventional solidification (CS, 30 °C/s). Besides, Mg atoms tend to be trapped in Al matrix under SRS, inducing suppression of Mg2Si, and promoting generation of AlFeSi phase. After being solution heat treated (T4 state), samples following the SRS route have lower yield strength compared with that by CS route, indicating better formability in SRS sample. After undergoing pre-strain and artificial aging (T6 state), the SRS samples have comparable yield strength to CS samples, satisfying the service requirements. This work provides technological support to industrially manufacture high performance AA6xxx series alloys with competitive advantage by a novel, short and low-cost process, and open a door for the further development of twin-roll casting based on SRS technique in industries.
 Select Wetting behaviors of molten melt drops on polycrystalline Al2O3 substrates in high magnetic fields Tie Liu, Yubao Xiao, Zhengyang Lu, Noriyuki Hirota, Guojian Li, Shuang Yuan, Qiang Wang J. Mater. Sci. Technol., 2020, 41 (0): 187-190.  DOI: 10.1016/j.jmst.2019.08.037 We measured the contact angles of Al and Sn drops on polycrystalline Al2O3 substrates in various high magnetic fields at different temperatures. The contact angles of both Al and Sn drops on the Al2O3 substrates decreased under high magnetic fields. These decreases strongly depend on the temperature, magnetic flux density, magnetic properties of the metal drops, and the reactivity of the metal drops with Al2O3. Our results reveal that the wetting behavior of molten metal drops on ceramics can be modified by a high magnetic field.
 Select Microstructure, wear resistance, and corrosion performance of Ti35Zr28Nb alloy fabricated by powder metallurgy for orthopedic applications Wei Xu, Xin Lu, Jingjing Tian, Chao Huang, Miao Chen, Yu Yan, Luning Wang, Xuanhui Qu, Cuie Wen J. Mater. Sci. Technol., 2020, 41 (0): 191-198.  DOI: 10.1016/j.jmst.2019.08.041 A ternary Ti35Zr28Nb alloy was fabricated by powder metallurgy (PM) from pre-alloyed powder. The microstructure, hardness, corrosion behavior, and wear response of the produced alloy were investigated systematically. The results show that nearly full dense Ti35Zr28Nb alloy (relative density is 98.1 ± 1.2 %) can be fabricated by PM. The microstructure was dominated with uniform β phase. The Ti35Zr28Nb alloy displayed spontaneous passivity in a naturally aerated simulated body fluid (SBF) solution at 37 ± 0.5 °C. The Ti35Zr28Nb alloy exhibited the highest corrosion resistance as compared to as-cast Ti6Al4V and pure Ti because of the formation of a protective passive film containing TiO2, Nb2O5, and ZrO2, including the highest corrosion potential (-0.22 ± 0.01 V), the lowest corrosion current density (57.45 ± 1.88 nA), the lowest passive potential (0.05 ± 0.01 V) and the widest passivation range (1.29 ± 0.09 V). Under the same wear condition, the wear rate of the Ti35Zr28Nb alloy (0.0021 ± 0.0002 mm3/m·N) was lower than that of the CP Ti (0.0029 ± 0.0004 mm3/m·N) and close to that of the Ti6Al4V (0.0020 ± 0.0003 mm3/m·N). The wear mechanism of the Ti35Zr28Nb alloy was mainly dominated by abrasive wear, accompanied by adhesive wear. The highest corrosion resistance together with the adequate wear resistance makes the PM-fabricated Ti35Zr28Nb alloy an attractive candidate for orthopedic implant materials.
 Select Comparative study of performance comparison of AlSi10Mg alloy prepared by selective laser melting and casting Qian Yan, Bo Song, Yusheng Shi J. Mater. Sci. Technol., 2020, 41 (0): 199-208.  DOI: 10.1016/j.jmst.2019.08.049 The influence of the microstructure on mechanical properties of AlSi10Mg fabricated by casting and selective laser melting (SLM) were investigated and contrasted in this work, with an emphasis on understanding the forming mechanism. The microstructure, phase structure and mechanical properties were characterized by scanning electron microscopy/field-emission Transmission Electron Microscopy (SEM/TEM), X-Ray Diffraction (XRD), tensile and fatigue tests. The results indicated that the SLM AlSi10Mg exhibited a supersaturated Si network structure precipitated along α-Al cell. Brittle β-Al5FeSi and π-Al8FeMg3Si6 phases were found in the as-cast and SLM AlSi10Mg respectively due to different thermal histories during processing. The SLM AlSi10Mg showed higher tensile strength but lower elongation than the casting, as the result of grain refinement and tortuous crack path. The fatigue results revealed that unmelted powder, oxide inclusion and pores can considerably degrade the fatigue properties for the SLM AlSi10Mg. The SLM process offered a new method for material processing that would avoid harmful Fe-bearing intermetallic compounds and refine the microstructures for enhancing strength.
 Select On the origin of the high tensile strength and ductility of additively manufactured 316L stainless steel: Multiscale investigation Bassem Barkia, Pascal Aubry, Paul Haghi-Ashtiani, Thierry Auger, Lionel Gosmain, Frédéric Schuster, Hicham Maskrot J. Mater. Sci. Technol., 2020, 41 (0): 209-218.  DOI: 10.1016/j.jmst.2019.09.017 We report that 316L austenitic stainless steel fabricated by direct laser deposition (DLD), an additive manufacturing (AM) process, have a higher yield strength than that of conventional 316L while keeping high ductility. More interestingly, no clear anisotropy in tensile properties was observed between the building and the scanning direction of the 3D printed steel. Metallographic examination of the as-built parts shows a heterogeneous solidification cellular microstructure. Transmission electron microscopy observations coupled with Energy Dispersive X-ray Spectrometry (EDS) reveal the presence of chemical micro-segregation correlated with high dislocation density at cell boundaries as well as the in-situ formation of well-dispersed oxides and transition-metal-rich precipitates. The hierarchical heterogeneous microstructure in the AM parts induces excellent strength of the 316L stainless steel while the low staking fault energy of the as-built 316L promotes the occurrence of abundant deformation twinning, in the origin of the high ductility of the AM steel. Without additional post-process treatments, the AM 316L proves that it can be used as a structural material or component for repair in mechanical construction.
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text:
# Symbol question

does anyone know what the symbol that looks like a tall pi means?

Related Introductory Physics Homework Help News on Phys.org
chroot
Staff Emeritus
Gold Member
You mean this symbol?

$$\prod{i}$$

If so, it means "the product of all values i." It's a cousin of the summation sign,

$$\sum{i}$$

which means "the sum all values i."

- Warren

so much better. thank you.


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# A population dynamic mechanism for the Constant Rate Effect (and beyond)

Kauhanen, H. & Walkden, G. (2015) A population dynamic mechanism for the Constant Rate Effect (and beyond). 22nd International Conference on Historical Linguistics. Naples, Italy, 27–31 July 2015.


text:
Double Integals and Volume

1. Oct 21, 2014

_N3WTON_

1. The problem statement, all variables and given/known data
Evaluate:
$\int_{0}^{a} \int_{0}^{b} e^{max(b^{2}x^{2}, a^{2}y^{2})} dy \hspace{1 mm} dx$
Where a and b are positive.

2. Relevant equations

3. The attempt at a solution
I'm having some trouble getting started with this problem, mostly because I am not very familiar with the notation. I am assuming that the "max" portion of the question means "the set of points of the argument for which the function attains its max value"? That is from the wikipedia page for "Arg max". If that is correct then I am looking for the volume of the region where the given argument of e takes on a maximum value, no?

2. Oct 21, 2014

Dr.D

Beats me! I would never write anything quite that way, so I have no clue what it means. Best to ask the original author what he had in mind.

3. Oct 21, 2014

_N3WTON_

Unfortunately that's not possible. Anyway, thanks for your time :)

4. Oct 22, 2014

_N3WTON_

Anyone have any ideas? I know it looks like I haven't really made an effort here, but that's honestly because I don't know where to start :/

5. Oct 22, 2014

Saitama

Start with determining the regions where $b^2x^2>a^2y^2$ and $a^2y^2>b^2x^2$, can you see on what region you are integrating?

6. Oct 22, 2014

_N3WTON_

so I would need to separate double integrals, divided by a line right? I just don't see how to obtain that line. Does that make any sense?

7. Oct 22, 2014

Staff: Mentor

I think it's probably simpler than this. Max{b2x2, a2y2} chooses the larger of the two numbers.

The region over which integration takes place is the rectangle whose corners are at (0, 0), (a, 0), (a, b), and (0, b). If b2x2 > a2y2, then bx > ay (since x and y are nonnegative and it's given that a and b are positive). In this case, what does the integrand simplify to? What part of the rectangle does bx > ay represent?

On the other hand, if b2x2 < a2y2, then bx < ay. Same questions as before.

8. Oct 22, 2014

Orodruin

Staff Emeritus
I would start with a variable substitution, the integral is going to look much more symmetric after that... Then you can split it into two regions which will be equivalent and give the same contribution so you only need to compute one integral.

9. Oct 22, 2014

_N3WTON_

So could I use bx = ay as a line segment that separates two non-intersecting regions and then set up two separate double integrals? One that looks like:
$\int_{0}^{a} \int_{0}^{\frac{bx}{a}}$
And another:
$\int_{0}^{b} \int_{0}^{\frac{ay}{b}}$

10. Oct 22, 2014

Saitama

Yes.

11. Oct 22, 2014

Staff: Mentor

I hadn't thought about it quite like this, but I think that something like this will work, provided you have the right limits of integration.

BTW, I've always found it easier to keep track of things in iterated integrals by writing in the variable in the limits of integration. Like this:
$$\int_{x = 0}^{a} \int_{y = 0}^{b} \dots dy dx$$

12. Oct 22, 2014

_N3WTON_

Oh, I thought that is what you were hinting at by writing bx>ay and ay>bx.....Also, that is a good suggestion, I've found myself getting confused sometimes because I can't remember which limit belongs to which variable...

13. Oct 22, 2014

_N3WTON_

Thank you!

14. Oct 22, 2014

_N3WTON_

I'm afraid I'm not entirely sure what you mean...
Edit: you just mean a simple u-sub?

15. Oct 22, 2014

Orodruin

Staff Emeritus
There is a trivial substitution which will make your integral area as well as the integrand symmetric in the integration variables. If you do it, both of the split integrals will be the same and you can multiply by two instead of doing two (admittedly very similar) integrals.

16. Oct 22, 2014

_N3WTON_

Awesome, thanks for the help..

17. Oct 22, 2014

_N3WTON_

Ok, I ended up solving using the integrals I posted earlier (unfortunately, I couldn't figure out the sub Orodruin referred to, perhaps he'd be so kind as to tell me). Here is my solution:
$\int_{0}^{a} \int_{0}^{\frac{bx}{a}} e^{b^{2}x^{2}} dy \hspace{1 mm} dx + \int_{0}^{b} \int_{0}^{\frac{ay}{b}} e^{a^{2}y^{2}} dx \hspace{1 mm} dy$
$= \int_{0}^{a} \frac{bx}{a} e^{b^{2}x^{2}} \,dx + \int_{0}^{b} \frac{ay}{b} e^{a^{2}y^{2}}\,dy$
$= \frac{b}{a} \int_{0}^{a} xe^{b^{2}x^{2}}\,dx + \frac{a}{b} \int_{0}^{b} ye^{a^{2}y^{2}}\,dy$
Here, I performed a u-sub on each integral, for the first integral I did:
$u = b^{2}x^{2} \hspace{2 mm} du = 2b^{2}x dx$
For the second integral:
$u = a^{2}y^{2} \hspace{2 mm} du = 2a^{2}y dy$
So then the integrals become:
$= \frac{b}{2b^{2}a}\int_{0}^{a} 2b^{2}xe^{b^{2}x^{2}}\,dx + \frac{a}{2a^{2}b}\int_{0}^{a} 2a^{2}ye^{a^{2}y^{2}}\,dy$
$= \frac{b}{2b^{2}a}[e^{b^{2}a^{2}}-1] + \frac{a}{2a^{2}b}[e^{b^{2}a^{2}}-1]$
And finally, I arrived at my final answer:
$= \frac{(e^{b^{2}a^{2}})-1}{2ab}$

Last edited: Oct 22, 2014
18. Oct 22, 2014

Orodruin

Staff Emeritus
Try $x = at$ and $y = bs$. The integral in the end is the same, but you only need to do it once and have less constants to worry about.

19. Oct 22, 2014

_N3WTON_

thanks a lot, I'll try it out

20. Oct 22, 2014

_N3WTON_

Also I just realized I made a mistake, the final answer should be:
$\frac{(e^{a^{2}b^{2}}-1)}{ab}$


text:
# Why is the identity element of a group denoted by $e$?

The question was asked by a student, and I did not have a ready answer. I can think of the German word Einheit'', but since in German that is not how the identity element of a group is called, I doubt that is the origin. Any ideas?

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"but since in German that is not how the identity element of a group is called" ... Sometimes it is indeed called like this. Also the identity matrix is frequently or at least not rarely called 'Einheitsmatrix'. Another thought: Sometimes the identity element in a multiplicative group is called (perhaps sloppily) Einselement (where 'eins' means 'one'). –  quid Feb 7 '12 at 14:09

Heinrich Weber uses Einheit and e in his Lehrbuch der Algebra (1896).

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That is almost certainly the origin, though it should be noted that one in Russian is "edinica". –  Igor Rivin Feb 7 '12 at 14:58
@Igor: The influential early textbooks on algebra tended to be written in German, unfair though that may be to those of us who grew up with English (or Russian). Quite a bit of common terminology and notation in mathematics seems to have originated in German work during the 19th century, such as the symbols $K,k$ for fields. –  Jim Humphreys Feb 7 '12 at 20:55
Well, Weber surely popularized the term. But his friend Dedekind used "einheit" before him to mean either a unit in a field, or a unit measure in geometry, and I'll bet if you look in his work you'll find it for groups. Probably if you dig into the 19th century you can find a series of earlier and earlier, vaguer and vaguer, uses of the term for a group identity. –  Colin McLarty Dec 29 '12 at 17:35
In todays German literature, it seems that Einselement (or even neutrales Element) is preferred over Einheit (which is used for units, i.e. invertible elements of a ring). –  Hagen von Eitzen Feb 8 '14 at 21:49

The Encyklopädie article of Heinrich Burkhardt, Endliche discrete Gruppen (1899), p. 218 ascribes the origin thus:

15. Allgemeiner Gruppenbegriff. (...) die Gruppe enthält ein Element $e$, die Einheit $^{73)}$, das mit jedem andern $a$ $ae = a$ und $ea = a$ ergiebt; (...)

73) (...) G. Frobenius u. E. Stickelberger, J. f. Math. 86, 1879[78], p. 219.

The paper in question, Ueber Gruppen von vertauschbaren Elementen (1879), reads:

§.1. Definitionen.

Die Elemente unserer Untersuchung sind die $\varphi(\mathbf M)$ Klassen von (reellen) ganzen Zahlen, welche in Bezug auf einen Modul $\mathbf M$ incongruent und relativ prim zu demselben sind. (...) Das Element $\mathbf E$ (so bezeichnen wir im folgenden die Zahlenklasse, deren Repräsentant 1 ist) heisst das Hauptelement.

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I'm confused. So, the conclusion is that the choice of E by Frobenius and Stickelberger is unmotivated (as their term for the unit is Hauptelement), and its identification with Einheit by later researchers (such as Burkhardt) is a false etymology? –  Emil Jeřábek Apr 28 at 11:04
@EmilJeřábek I agree that without further evidence of the transition, it's hard to tell how influential F & S's (pervasively used) E was in the eventual choice of e. They do tie it with eins insofar as their term for the unit is also Klasse von 1 (in quote above). –  Francois Ziegler Apr 28 at 23:23

The identity element for a complex number is (1,0)=1. The german word for "one" is "eins" so we write e.

http://de.wikipedia.org/wiki/Neutrales_Element

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this seems speculative, compared with the sources quoted by Francois Ziegler –  Yemon Choi Apr 26 at 17:53