Auto study on browsers

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Now there are many classes to study. These web applications always check the user’s action frequently. Once it finds the user is not operate the computer, the course will stop. I developed a program to anti-check and make the web application run continuously. Injection JavaScript to the web application Tampermonkey is a popular userscript manager. … Read more

Obtain the cylindrical field components in Comsol.

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Comsol is a powerful software to solve the Helmholtz equation in Cartesian coordinates. However, there are many problems based on the cylindrical field. The cylindrical field components are more interesting than the cartesian components. Here is how to obtain the cylindrical field components from the cartesian components in Comsol. The general idea is coordinate transform. … Read more

Web worker

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There is only one thread for Javascript in browsers. It is enough for the browser to deal with the UI actions. However, the CPU became multi-thread and the Javascript can do much more work in browser. Web workers are developed to utilize multi-core CPU more effectively. The simplest use of workers is for performing a … Read more

Latex equation in word

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It a good news that word has already known the latex in the equation editor. Here is some tips to input the equation with latex. The short key for insert a equation is ALT++. It is quick easy to remember because there is always a “=” in the equation. Most of the latex symbols are … Read more

Mode Selection for a gyrotron cavity

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The microwave is reflected at the wall of the cavity to form the standing wave in a closed cavity. If the plane boundary surfaces are at z=0 and z=d, the boundary conditions can be satisfied at each surface only if \(d=p \frac{\lambda_g}{d}\,\,\,\, p=1,2,3,…\) where \(lambda_g\) is the waveguide length, p is the mode number in … Read more

回旋管腔体设计

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截止段 L1 决定了场能否在入口端充分截止。 均匀段L2的长度决定能量交换率和Q值。 输出段 L3对腔体 Q值的影响也较大 ,同时它还和能量输出有关。为了减小由回旋管输出窗反射回来的电磁波对互作用区注 波互作用的影响 ,可以适当加大 L3长度。

Save the result in Mathematica

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Mathematica notebook is a powerful tool to save all the program and data together. Sometimes it is much better to save the result in a separated file for re-use. For example, there is a script to scan the parameters in a wide range. It may take a lot of time. The result is always a … Read more

Get the plot data in comsol application program

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Comsol is good at post processing and visualization. However some special analysis is necessary in the comsol application program. For example, determine to mode number in special direction after a eigen mode analysis. The comsol can plot the electrical field along a line but it doesn’t tell the mode number. We have to write some … Read more

Transverse electric(TE) wave in circular waveguides

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Circular waveguides offer implementation advantages over rectangular wave guide is that installation is much simpler when forming runs of turns and offsets. The uniform section in the gyrotron cavity is a circular waveguide. The working mode is usually a transverse electric mode in the cavity. Here is a calculator for the Transverse Electric mode in … Read more