What's New?

• PostScript File Directory

  The directory was uploaded on 14 Mar 10 along with a revised version of the ellipsometry section on growth of a single surface layer.

• The Trojan Asteroids

  I uploaded a revised version of this section on 28 Feb 10. PostScript and BBC Basic source code has been added. I will be adding a directory of the PostScript programs for the convenience users who want to make hard-copy figures.

• Diffraction

  I uploaded a revised version of the Diffraction section on 15 Feb 10. The material has been reorganized to enable PostScript programs to display the patterns conviently on 8.5"x11" pages. The X-ray diffraction section is not included. It will reappear when I decide on a layout for the PostScript version.

• PostScript

  The number of PostScript files in Jack's Page has fluctuated over the years. Originally, they (along with files for the HP 48 calculator) were included merely as examples of programs that could be run on devices other than a computer. More recently, GSview has made PostScript a convenient programming language for Windows. If files with the "eps" extension are directed to open in GSview, PostScript is also a convenient language for web pages. It is not interactive (no buttons), it cannot portray animation, and it is slower than Java (faster than BBC or Liberty Basic), but it has many good features. It uses "{" and "}" in the same way as Java, and programs can be written to look very much like Java applets (provided the stack is used only for arithmetic). A program can be sent directly to a PostScript printer, or to any printer from GSview. The files I am uploading today (7 Jan 10) are found in Gravitational and Electrostatic Fields. Four Java applets have been combined into one, and a single PostScript program lays out the resulting four field plots on an 8.5"x11" sheet. I have a new HP CP 2025dn colour laser printer with PostScript level 3 emulation, and the field plots it produces are excellent.

  I plan to add more PostScript programs over the course of the next year. Some will be updated versions of programs I deleted during my last major revision of Jack's Page.

• BlackBerry Project

  Jack's Page is based on Java applets that run in the user's computer. Source code is provided in Java for the user who wants to modify an applet, and in Basic for the user who prefers a simpler language. Users will find little of interest in Jack's Page if they access it on a Blackberry or similar device that does not support Java applets. In order to give BlackBerry users something to look at, on 14 Oct 09 I uploaded six bitmap files showing results calculated by Java applets. On 16 Dec 09 I decided this was a mistake, and removed them. Handheld devices are evolving rapidly, and in year or two I expect they will run Java applets, a PostScript interpreter, or some form of Basic. Until then I will focus on other projects.

• Java Applet Layout

  Recent software updates have forced me to change the way I layout Java applets. I uploaded revised applets that deal with the problem on 6 Oct 09.