快脉冲直线变压器驱动源模块的原理及实验

 介绍了直线型变压器驱动源（LTD）产生快脉冲的基本原理及技术优势,阐述了快脉冲LTD模块设计的要点,设计了输出脉冲上升时间小于100 ns的快脉冲LTD模块,并进行了初步的实验研究。实验得到该LTD模块充电±16 kV时,短路放电的电流峰值为23.7 kA,电流振荡1/4周期为69.6 ns;充电±50 kV驱动0.85 Ω负载时,电流峰值为41.4 kA,上升时间为36.8 ns（10%~90%）和60.8 ns（0~100%）。     

原子力显微镜在生物物理领域的新应用

介绍了原子力显微镜在生物物理领域的最新应用:蛋白质去折叠、DNA拉伸、生物膜受力,通过分析实验得到的力谱,可以获取关于蛋白质、DNA、生物膜结构信息.原子力显微镜不仅能反映测量体系的力学性质,由于其具有独特的时间、空间分辨及实时成像,因而能提供更多信息.     

2-羟基-5-磺酸基苯基重氮氨基偶氮苯分光光度法测定痕量汞(Ⅱ)

研究了 2 羟基 5 磺酸基苯基重氮氨基偶氮苯 (HSDAA)与汞 (Ⅱ )的显色反应。在TritonX 10 0存在下 ,于pH 10 30的硼砂 氢氧化钠缓冲溶液中 ,汞 (Ⅱ )与试剂形成 1∶2的稳定橙红色配合物 ,其最大吸收波长位于 5 19nm处 ,表观摩尔吸光系数为 1 6 7× 10 5L·mol- 1 ·cm- 1 。汞 (Ⅱ )在 0～ 6 0 0 μg·L- 1 之间符合朗伯 比尔定律。该法直接应用于水样中痕量汞的测定。     

InAs Quantum Dots On (001) GaAs Substrate with two Groups of Different Sizes Under Arsenic Shutter Closed Condition

The effect of temperature on the self-assembled InAs quantum dots (QDs) grown on GaAs substrate under arsenic shutter closed condition has been studied. From atomic force microscopy (AFM), it was found that the size of InAs dots exhibited a transition from single-sized uniformly distributed quantum dot (QD) at a growth temperature of 490°C to two groups of different sizes QDs at 510°C. Since the desorption rate of In atoms from the substrate surface is very high at 510°C, a growth model is proposed that attributes the larger sized QDs to the enhanced capture of desorbed In atoms by a local random protrusion which initiates a regenerative capture and growth process and leads to explosive growth.     

Modified wavelet based morphological correlation for rotation-invariant recognition

A wavelet-based rotation invariant morphological correlation (WBRIMC) is proposed as a new architecture to improve the properties of the classical rotation invariant morphological correlation (RIMC). For the WBRIMC, the JPS of the RIMC is filtered by an appropriately dilated power spectrum function of wavelet. Simulation results confirm that the WBRIMC has higher discrimination capability with sharp and intense correlation signals, and is more tolerant to the salt-and-pepper noise and white additive Gaussian noise than is the Circular harmonic filter (CHF), the phase only CHF (POCHF) and the RIMC.     

Effect of pyrolytic polyacrylonitrile on electrochemical performance of Si/graphite composite anode for lithium-ion batteries

The silicon/graphite (Si/G) composite was prepared using pyrolytic polyacrylonitrile (PAN) as carbon precursor, which is a nitrogen-doped carbon that provides efficient pathway for electron transfer. The combination of flake graphite and pyrolytic carbon layer accommodates the large volume expansion of Si during discharge-charge process. The Si/G composite was synthesized via cost-effective liquid solidification followed by carbonization process. The effect of PAN content on electrochemical performance of composites was investigated. The composite containing 40 wt% PAN exhibits a relatively better rate capability and cycle performance than others. It exhibits initial reversible specific capacity of 793.6 mAh g^?1 at a current density of 100 mA g^?1. High capacity of 661 mAh g^?1 can be reached after 50 cycles at current density of 500 mA g^?1.     

光谱成像技术无损鉴别西洋参饮片的研究

应用电可控液晶光谱成像装置,测定不同市售来源的西洋参饮片,以期为其质量控制提供新的方法。系统光谱分辨率5nm,光谱覆盖范围为405～680nm,空间分辨率50lp·mm-1。从成像光谱立方体中提取特征光谱曲线,构建饮片指纹图谱;采用主成分等聚类分析方法解析其指纹图谱,用于饮片真伪鉴别与质量判定。结果与性状,显微及理化鉴定结果相吻合。表明光谱成像分析技术可用于中药指纹图谱的构建和质量评价,操作方法简便、快速、无损。     

First principles simulation technique for characterizing single event effects

This paper develops a new simulation technique to characterize single event effects on semiconductor devices. The technique used to calculate the single event effects is developed according to the physical interaction mechanism of a single event effect. An application of the first principles simulation technique is performed to predict the ground-test single event upset effect on field-programmable gate arrays based on 0.25 μm advanced complementary metal-oxide-semiconductor technology. The agreement between the single event upset cross section accessed from a broad-beam heavy ion experiment and simulation shows that the simulation technique could be used to characterize the single event effects induced by heavy ions on a semiconductor device.     

LD side-pumped 41 W high beam quality acousto-optical Q-switched single-rod Nd:YAG laser

We report a LD side-pumped high beam quality (M _x ² = 1.20 and M _y ² = 1.19) acousto-optic (AO) Q-switched single-rod Nd:YAG laser with a TEM₀₀-mode dynamic stable cavity. At the pump power of 600 W, 41 W TEM₀₀-mode 1064 nm laser was achieved with electro-optical conversion efficiency of 7%. The repetition rate and pulse width were 30 kHz and 102 ns, respectively with pulse energy of 1.4 mJ and peak power of 13 kW. Up to 24 W of 532 nm green laser was generated by external frequency doubling, corresponding to 59% optical conversion efficiency.