开关放电分散性对FLTD模块输出的影响模拟

建立了包含开关放电分散性的电路模型,模型通过电压控制开关和自击穿开关模型的结合,可对开关抖动及支路间放电的相互影响进行模拟,利用研制的300 kA单级直线型变压器驱动源(FLTD)模块进行了实验验证,模拟结果与实验相吻合。进而针对设计的20支路FLTD模块建立了电路模型,模拟分析了模块支路开关放电分散性对输出电流峰值和上升沿的影响,模拟结果表明,开关抖动小于5 ns时对模块输出影响较小。     

电磁轨道炮高速滑动接触电阻的定量表征

从描述电磁轨道炮炮口电压波形的场路模型出发,构建了电枢/轨道高速滑动接触电阻与轨道电流波形、炮口电压波形、电枢膛内速度曲线和轨道结构参数之间的关系,依据此关系可定量表征电磁轨道炮高速滑动接触电阻。实例计算表明,电枢/轨道高速滑动接触电阻的变化依赖于轨道电流变化,对应电流上升段、平顶段和电流下降段。在平顶段接触电阻最小约0.2 m,在电流上升段和电流下降段,接触电阻达3 m。     

自组装静电驱动微机电系统倾斜镜

研制了一种基于自组装技术的静电驱动微机电系统(MEMS)倾斜镜,并利用表面硅工艺PolyMUMPs制备了样品。倾斜镜主要由一个中心镜面,两个偏转梁和两个可实现自组装的复合悬臂梁组成。中心镜面离衬底的高度可通过增大金和多晶硅复合悬臂梁的残余应力梯度得到提升。热退火技术被用于提高金层的残余应力。器件结构利用有限元仿真软件进行了优化并通过实验进行了验证。经过200 ℃热退火后,倾斜镜的偏转角度可以达到3.6。该倾斜镜可运用于微光机电系统。     

偏振光实验方法的改进

用半导体激光电源代替常规的He—Ne激光光源进行偏振光实验,可使偏振光实验精度提高,操作更为简便。     

Novel fluorosilicone triblock copolymers prepared by two-step RAFT polymerization: Synthesis, characterization, and surface properties

Well-defined poly(dimethylsiloxane)-b-poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate-b-poly(styrene) (PDMS-b-PHFBMA-b-PS) triblock copolymers were prepared by two-step reversible addition-fragmentation chain transfer (RAFT) polymerization. The two-step RAFT polymerization proceeded in a controlled manner as demonstrated by the macromolecular characteristics of the blocks and corresponding polymerization kinetic data. Furthermore, surface properties and morphologies of the polymers were investigated with static water contact angle (WCA) measurement, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) which showed low surface energy and microphase-separation surfaces.     

A SQUID gradiometer module with large junction shunt resistors

A dual-washer superconducting quantum interference device(SQUID) with a loop inductance of 350 pH and two onwasher integrated input coils is designed according to conventional niobium technology. In order to obtain a large SQUID flux-to-voltage transfer coefficient, the junction shunt resistance is selected to be 33 ?. A vertical SQUID gradiometer module with a baseline of 100 mm is constructed by utilizing such a SQUID and a first-order niobium wire-wound antenna.The sensitivity of this module reaches about 0.2 fT/(cm·Hz1/2) in the white noise range using a direct readout scheme, i.e.,the SQUID is directly connected to an operational amplifier, in a magnetically shielded room. Some magnetocardiography(MCG) measurements with a sufficiently high signal-to-noise ratio(SNR) are demonstrated.     

A Facile Method to Assemble PNIPAM‐Containing Microgel Photonic Crystals

Structural colors: Poly(N‐isopropyl acrylamide) based microgel photonic crystals are fabricated by using a new method called “high‐temperature‐induced hydrophobic assembly”. The assembling conditions affect the water content of the crystals, thus determining their structural color (see image). The obtained photonic crystals are sensitive to solvents, and the reversible changes in their color can be observed with the naked eye.

     

HL—1装置表面分析站的研制

等离子体与表面相互作用的重要性是人们公认的。我们试图在HL-1装置上原位测量表面状态,本文叙述了为HL-1研制的表面分析站及测得的一些结果。为装置提供了实验数据。     

Direct writing waveguides inside YAG crystal by femtosecond laser

A 120 fs Ti-sapphire laser was used to fabricate waveguides in YAG crystal. A 7 mm long waveguide was written at a position of 100 μm below the surface, which shows multimode propagation at 633 nm with optical attenuation of about 0.2 dB/mm. The light guiding occurs in the region around the visible laser-damaged region, indicating that the light guiding area is induced by stress. The waveguide exhibited strong birefringence property with maximum magnitude of about 1.5 × 10⁻⁵. Infrared and Raman spectroscopy analysis indicate there is no change in chemical composition in laser-modified zone.