muwn's PhD Project

Syntax highlight file for Surface Evolver

2007-11-19T12:09:00.001-08:00

This a the syntax highlight file for surface evolver. Download here.

Surface Evolver Tips

2007-10-25T09:49:00.000-07:00

The following are several tips for quicker master Surface Evolver script:

not refine to the final resolution at the beginning. Run at low resolution at beginning, refine it during evolution. For example, like g; r; u 3; g2; V 3; u;
try use u 3; every time you do the refine. ru={r; u 3}
In my experience, V is never harmful. put u 3 after V 3 all the time. Vu={V 3; u 3;}
follow g 3 after Vu, Vug={Vu; g 3}
hessian should be carefully be used. It may cause a disaster if used improperly. If you've got nonnegative/nonpositive in your constraint, avoid use it.
the scale value every time you run g shows is important indication for the evolution process. zero means evoluiton run into a wrong situation.

Tips of exporting vectorwork model to ansys

2007-09-17T16:00:00.000-07:00

Here are some tips for exporting vectorwork model to ansys

you can either use SAT(3D only) or IGES(3D only), but SAT is prefered. Normally sat give better result.
Be aware the units. In vectorwork, try using the highest precision, and use International system.
you can only extrude a 2D object to 3D inside the symbos or not using symbol at all. you can't combine (add surface) of any 2D symbol to one.

Draw MEMS Process Steps Through Matlab (2)

2007-08-31T03:59:00.000-07:00

improved surface smoothing. Download from here.

A brief history of seismocardiography

2007-08-17T08:37:00.000-07:00

"Seismocardiography is a noninvasive technique developed for recording and analyzing cardiac vibratory activity as a measure of cardiac contractile performace. " [1]

--Early Age--

As far as in 1961, Russian scientist BOZHENKO BS published a paper Seismocardiography--a new method in the study of functional conditions of the heart. It can be trust that the term seismocardiography (SCG) is first proposed in this paper. Later in 1964, Russian scientist BAEVSKII RM, et, al published another paper SEISMOCARDIOGRAPHY.

In 1976, the first application of this technique seems also come from Russian scientists. Bal'maqiia TA and his colleagues used SCG to examine healthy infants and young children .

Regretfully, so far, none of these original papers has been found through Internet, not even the English translation.

--Morden Age--

In 1988, American scientist Salerno DM & Zanetti JM patented Cardiac compression wave measuring system and method, where the term seismocardiography is first proposed in western and registered. It use seismic techniques and principle to measure cardiac performance by detecting compression waves generated by heart muscle function [2].

In this patent, an seismic accelerometer (usually piezoelectric accelerometer) high sensitivity at ultra-low frequency (0-800Hz) is placed on the chest region of a horizontally disposed patient. Tha analog signals is read and passed through a low-pass fileter (0-50Hz).

In 1991, Salerno DM & Zanetti JM's published a paper Seismocardiography: a technique for recording precordical acceleration, which marked the academic study of SCG. Later in the same year, Salerno and Zanetti, with other colleagues published several papers concerning the potential applications of this technique. These research studied the effect of some abnormal cardiac activities to the signal of SCG, those activities include obstruction of coronary blood flow during balloon angioplasty [3], left ventricular function change during ischemia [4]. Piezoelectric accelerometer was chosen as transducer during their experiments. Signal pattern identification and noise analysis is another important work carried out during their initial researches [5].

In 1994, relationship between seismocardiogram and echocardiogram for events in the cardiac cycle is studied by ganroth, Hannan P, Salerno DM.

In 1999, the SCG grabbed attention of Zanetti JM for its magnetic-field-compatible, which is extremelly useful during MRI process [6]. It provide a alternative method for ECG, which has restriction application in MRI by its very nature.

In 2002 and 2005, polish Piotrowicz R. carried out the experiment of using SCG to estimate left ventricular function and coronary artery disease [7][8]. No full text papers has been found yet. It is interesting that these expierments have the same focus in the research carried out by Salerno DM and Zanetti JM, et, al in 1991.

In 2003 and 2004, vibration isolation of SCG during MRI is studied by K. Naemura, et, al in [12][13].

In 2006, Pavel Smrcka (Czech) proposed a method for pseudo-period detection in seismocardiographic signal[9].

In 2007, Jared B Shell (US) used low-cost geophone aceelerometer carried out three-axis seismocardiography [10].

Draw MEMS Process Steps Through Matlab

2007-08-13T16:23:00.000-07:00

A small matlab program has been wroten to assist the layout of MEMS process. Normally, MEMS processes include deposit, LIGA (lithography), and etching. This program is based on this concept as well. By just simply write the deposit, LIGA, and etching commands, with their parameters, the MEMS cross section layout can be drawn after any step. The commands include:

loadlayerprofile() -- which stores all the preference parameters which can be altered at will.

deposit ('materailName', thickness) -- materialName currently support Si, SiO2, PR, metal. thickness shoulb between 1 and 10.
liga (pattern) -- pattern is an char array like ' --- -- - ---', the length is variable, while the blank means etched photo resistor.
etch ('materialName') -- currently support anisotropic etching only.
removepr() -- remove all the PR current on the surface.
drawlayers() -- can be put after any command above. This command draw the current cross section view.

Example:
clear all;
clear global;
loadlayerprofile('MEMS');

figure(1);
deposit ('Si', 10);
deposit('SiO2', 1);
drawlayers();

deposit('Si', 6);
deposit('PR', 1);
drawlayers();
liga(' - ---- - ');
etch ('Si');
removepr('PR');
drawlayers();

deposit('metal', 2);
deposit('PR', 1);
liga(' -- ');
etch ('metal');
removepr('PR');
drawlayers();

deposit('PR', 1);
liga('-- -------------- --');
drawlayers();
etch ('SiO2');
drawlayers();
etch ('Si');
removepr('PR');
drawlayers();
axis ([0 100 0 120])

RESULT:

How to generate a symbol relationship tree in vectorworks

2007-08-12T04:55:00.000-07:00

Using vectorworks to produce MEMS mask layout means using simple symbols to form larger and complexer symbols. There is no straight way to generate the symbols relationship automatically. An possible way I sorted out is as following:

export your final work to vectorscript file.
using a matlab script I wrote to read this vectorscript file. According to the symbol function inside the script file, an relationship chart will be generated automatically.

At this moment, it only support the first level of the relationship.

Vectorscript tips

2007-07-23T07:53:00.000-07:00

If {$INCLUDE function/procedure} is included inside a procedure. The all the variables defined in the parent procedure can be accessed directly from included functions/procedure.

Do not write a matlab function without input argument!

2007-07-12T06:57:00.001-07:00

use
matlabfunction();
instead of
matlabfunction;

Latex learning (1)

2007-07-10T18:13:00.000-07:00

\usepackage[,,,] {geometry} % to set page size etc.

\usepackage{latexsym} % to use some special symbols in latex

Flow chart of vectorscript for mask layout

2007-07-09T11:57:00.000-07:00

mlXXX functions are a set of tools to simplifier metal line layout.

mlClrPat(path: ARRAY (1..10) OF POINTstruc): clear the data in path.

mlDirectToPat(): add next point's positon to the path. The position is determined by next point's direction and distance relating to current point. The direction from current point to next point is presented by 1,2,3,4 each represent to left->right, down -> up, right->left, up->down.

mlPatToTube(): Draw single line according to the point array stored in path. Round curve for turn corner is automatically generated during the drawing.

mlPatToDTube(): Similar to mlPatToTube, but generate two parallel metal lines in stand one metal line.

mlPatToDirect, mlLineFromTo, mlAreFromTo are three sub-precedures called only by mlPatToTube and mlPatToDTube only.

Tips for vecterscript

2007-07-04T10:49:00.000-07:00

DON'T use name like Path, Clear in variables and procedure or functions.
Each variable defined in procedures's parameter list should has a VAR before them if you want them feed the value back.
DONT use from/to as variables.
No END; needed for IF statement if ELSE is after used.
FlipHor/FlipVer is different from HRotate

The silicon thermal conductivity

2007-06-05T19:11:00.000-07:00

/Thermal flux for two 2D radiation parallel planes./
Now, the problem has been clear. Silicon thermal conductivity is reason of the result of the radiation simulation. Though temperature distribution along the area can't tell any information about the radiation. The thermal flux clearly shows the heat loss.

The big value of thermal conductivity of silicon has its benefit that it make sure the temperature uniform along the surface.

The way to reduce the radiation is to using shield between the ceiling of the package and the top surface of die. That should be traded off with complexity.

Bothered by ANSYS

2007-06-05T12:54:00.000-07:00

These days I tried the radiation simulation in the ANSYS. Three methods available according to ANSYS thermal analysis guide. I tried the radiosity method, which used radiation boundary condition (SF, SFL, SFA commend, which also support convection boundary, etc) to realize the simulation.

However, the simulation result that the radiation effects seems much more smaller, is unexpected.

I want find a way to calculate the thermal conduction power in ANSYS.

Compile GUI.m/GUI.fig to GUI.exe

2007-06-01T06:23:00.000-07:00

Compile GUI.m/GUI.fig to GUI.exe

mcc -B sgl GUI.m
copy GUI.m/GUI.fig/GUI.exe to new pc
copy /extern/lib/win32/mglinstallar.exe to new pc
run mglinstaller.exe
extract... bin\win32

VectorScript tips

2007-05-24T17:15:00.000-07:00

If ArcTo is used when a polygon is build, an additional LineTo (px, py [which is the point of the end of the ArcTo]) should be added after ArcTo. This procedure make sure the correct result.

Finish DRIE mask.

2007-05-23T09:18:00.001-07:00

Made by vectorworks v12.5

Maple, MATLAB, MathCAD & Mathematica

2007-05-23T03:42:00.000-07:00

数学软件四大家Maple、MATLAB、MathCAD和Mathematica　　
目前在科技和工程界上比较流行和著名的数学软件主要有四个，分别是Maple、MATLAB、MathCAD和Mathematica。它们在各自针对的目标都有不同的特色。下面就让我为你一一道来。

一、Maple V 系统
　　Maple V是由Waterloo大学开发的数学系统软件，它不但具有精确的数值处理功能，而且具有无以伦比的符号计算功能。Maple V的符号计算能力还是MathCAD和MATLAB等软件的符号处理的核心。Maple提供了2000余种数学函数，涉及范围包括：普通数学、高等数学、线性代数、数论、离散数学、图形学。它还提供了一套内置的编程语言，用户可以开发自己的应用程序，而且Maple自身的2000多种函数，基本上是用此语言开发的。
　　Maple采用字符行输入方式，输入时需要按照规定的格式输入，虽然与一般常见的数学格式不同，但灵活方便，也很容易理解。输出则可以选择字符方式和图形方式，产生的图形结果可以很方便地剪贴到Windows应用程序内。

二、MATLAB 系统
　　MATLAB原是矩阵实验室（Matrix Laboratory）在70年代用来提供Linpack和Eispack软件包的接口程序，采用C语言编写。从80年代出现3.0的DOS版本，逐渐成为科技计算、视图交互系统和程序语言。MATLAB可以运行在十几个操作平台上，比较常见的有基于Windows 9X/NT、OS/2、Macintosh、Sun、Unix、Linux等平台的系统。
　　MATLAB程序主要由主程序和各种工具包组成，其中主程序包含数百个内部核心函数，工具包则包括复杂系统仿真、信号处理工具包、系统识别工具包、优化工具包、神经网络工具包、控制系统工具包、μ分析和综合工具包、样条工具包、符号数学工具包、图像处理工具包、统计工具包等。而且5.x版本还包含一套几十个的PDF文件，从MATLAB的使用入门到其他专题应用均有详细的介绍。
　　MATLAB是数值计算的先锋，它以矩阵作为基本数据单位，在应用线性代数、数理统计、自动控制、数字信号处理、动态系统仿真方面已经成为首选工具，同时也是科研工作人员和大学生、研究生进行科学研究的得力工具。MATLAB在输入方面也很方便，可以使用内部的Editor或者其他任何字符处理器，同时它还可以与Word6.0/7.0结合在一起，在Word的页面里直接调用MATLAB的大部分功能，使 Word具有特殊的计算能力。

三、MathCAD 系统
　　MathCAD是美国Mathsoft公司推出的一个交互式的数学系统软件。从早期的DOS下的1.0和Windows下的4.0版本，到今日的8.0版本，功能也从简单的数值计算，直至引用Maple强大的符号计算能力，使得它发生了一个质的飞跃。
　　MathCAD是集文本编辑、数学计算、程序编辑和仿真于一体的软件。MathCAD7.0 Professional（专业版）运行在Win9X/NT下，它的主要特点是输入格式与人们习惯的数学书写格式很近似，采用WYSWYG（所见所得）界面，特别适合一般无须进行复杂编程或要求比较特殊的计算。MathCAD 7.0 Professional 还带有一个程序编辑器，对于一般比较短小，或者要求计算速度比较低时，采用它也是可以的。这个程序编辑器的优点是语法特别简单。
　　MathCAD可以看作是一个功能强大的计算器，没有很复杂的规则；同时它也可以和Word、Lotus、WPS2000等字处理软件很好地配合使用，可以把它当作一个出色的全屏幕数学公式编辑器。

四、Mathematica 系统
　　Mathematica是由美国物理学家Stephen Wolfram领导的Wolfram Research开发的数学系统软件。它拥有强大的数值计算和符号计算能力，在这一方面与Maple类似，但它的符号计算不是基于Maple上的，而是自己开发的。
　　Mathematica的基本系统主要是用C语言开发的，因而可以比较容易地移植到各种平台上，Mathematica是一个交互式的计算系统，计算是在用户和Mathematica互相交换、传递信息数据的过程中完成的。Mathematica系统所接受的命令都被称作表达式，系统在接受了一个表达式之后就对它进行处理，然后再把计算结果返回。Mathematica对于输入形式有比较严格的规定，用户必须按照系统规定的数学格式输入，系统才能正确地处理，不过由于3.0版本引入输入面板，并且可以修改、重组输入面板，因此以前版本输入指令时需要不断切换大小写字符的繁琐方式得到很好的改善。5.1版本可以用各种格式保存文件和剪贴内容，包括RTF、HTML、BMP等格式。

Mathematica的符号功能是最强的。且它的运行构架是最优的。符号运算效力与解析能力是最好的（数值运算当然是Matlab最好）。它的构架由核心系统与前端系统构成。两个系统既合作又独立。这个比Matlab的构架都要优秀。它是专为研究人员开发的。至于Maple的符号能力根本就比 Mathematica弱很多的。它基本上是为中学生与大学生之学习研发的。不足以进行物理学与技术科学的运演。而Mathematica是最好的物理学科研的工具。Matlab是最好的技术科学数值求解的工具。朋友们应该知了。数值类的数学软件是Matlab最好最全。符号分析类的数学软件是 Mathematica最好。

五、四种软件的比较
　　选用何种数学软件?如果仅仅是要求一般的计算或者是普通用户日常使用，首选的是MathCAD，它在高等数学方面所具有的能力，足够一般客户的要求，而且它的输入界面也特别友好。如果要求计算精度、符号计算和编程方面的话，最好同时使用Maple和Mathematica，它们在符号处理方面各具特色，有些Maple不能处理的，Mathematica却能处理，诸如某些积分、求极限等方面，这些都是比较特殊的。如果要求进行矩阵方面或图形方面的处理，则选择MATLAB，它的矩阵计算和图形处理方面则是它的强项，同时利用MATLAB的NoteBook功能，结合Word6.0/7.0的编辑功能，可以很方便地处理科技文章。

cite from: http://www.math.org.cn/forums/index.php?showtopic=9899

substitute in vim

2007-05-22T16:56:00.000-07:00

Vim
Substitute strings in a line use:
:s/str2/str1/[g], where str2, to be substituted,
Substitute strings in the whole text:
:%s/str2/str1/[g]

MEMS handbooks

2007-05-19T17:23:00.000-07:00

1.Malfu N. An introduction to microelectromechanical systems engineering. Boston: Artech House, 2000
2.Lyshevski SE. Nano- and microelectromechanical systems : fundamentals of nano- and microengineering, Boca Raton: CRC Press,2001
3. Kamins T. Polycrystalline silicon for integrated circuits, Boston, MA: Kluwer Academic Publishers, 1988
4.Kovacs GTA. Micromachined transducers sourcebook, New York: McGraw-Hill, 1998
5.Madou M. Fundamentals of microfabrication, Boca Raton: CRC Press, 1997
6.Gad-el-Hak M. The MEMS Handbook, Boca Raton: CRC Press, 2001
7. Wai-Kai Chen .The VLSI Handbook. Boca Raton: CRC Press, 2000
8.Richard C. Jaeger. Introduction to microelectronic fabrication(Second Edition), New Jersey:Prentice Hall,2000
9.Stephen D. Senturia，Microsystem Design, Kluwer Academic Publishers, 2001
10.M.-H. Bao，Micromechanical Transducers: Pressure sensors, accelrometers, and gyroscopes ， Elsevier, New York, 2000.
11.William Trimmer,Micromechanics and MEMS: Classic and Seminal Papers to 1990. IEEE Press, New York，1997
12.Fujimasa I. Micro-machines —A new era in mechanical engineering, Oxford University Press, 1996
13.Bharat Bhushan，Handbook of Micro/Nano Tribology, Second Edition，CRC Press，1998
14.Sergey Edward Lyshevski，MEMS and NEMS: Systems, Devices, and Structures,CRC Press ,2002

Mechnical reliable!

2007-05-19T12:20:00.000-07:00

After refine the boundary condition, the quartar part of the device has been demonstrated to be mechanical reliable.