Characterization of Zn<Subscript>2</Subscript>SnO<Subscript>4</Subscript> Thin Films Prepared by RF Magnetron Sputtering

Zn₂SnO₄ (ZTO) is a stable semiconductor in ZnO–SnO₂ system and important transparent conducting oxide (TCO) predominantly used in optoelectronic devices. ZTO thin films were prepared by RF magnetron sputtering using Zn₂SnO₄ ceramic target in this paper. The effects of annealing temperatures and oxygen contents on characterization of ZTO thin films were studied. The results show that ZTO thin films prepared by RF magnetron sputtering are amorphous with an optical band gap of 3.22 eV. After annealing at 650°C in Ar atmosphere for 40 min, ZTO films possess a spinel structure with an optical band gap of 3.62 eV. The atomic force microscope (AFM) data of morphology reveals that the surface roughness of films is about 2 nm. The results of energy dispersive spectrometer (EDS) show that the concentration ratio of Zn to Sn is in the range from 1.44 to 1.57. The results of Hall-effect-measurement system reveal that the resistivity of films varies from 102 to 10–1 Ωcm, carrier concentration is about 10¹⁷ cm^–3, and mobility ranges from 10⁰ to 10¹ cm² v^–1 s^–1.     

Autaptic modulation-induced neuronal electrical activities and wave propagation on network under electromagnetic induction

Based on an improved HR neuron model, the effects of electrical and chemical autapses on the firing activities of single neurons are studied, and the wave propagation in forward feedback neural network is also discussed by considering autapstic regulation under different intensities of electromagnetic induction. It is found that the electrical activities of single neuron can be changed by exerting excitatory or inhibitory of electrical and chemical autapses. With different feedback gains of electromagnetic induction current, membrane potential shows the oscillatory solutions and steady states. Under the condition of different autapse or electromagnetic induction, the propagation of electrical activities caused by the central neuron is transformed in the forward feedback network. Moreover, the spatial synchronization of the network will be changed by choosing different coupling intensities and feedback gains. It is proved that the electrical and chemical autapses play a significant role in firing modes of single neuron and the wave propagation of the forward feedback networks under the electromagnetic induction.     

聚变等离子体中高能量粒子驱动的鱼骨模不稳定性研究

在考虑高能量粒子密度的空间分布及箍缩角分布的条件下,建立了研究鱼骨模的色散关系,并作了数值研究。结果表明：当高能量粒子的密度高于某个阈值时,鱼骨模会在高能量粒子密度梯度最大处被激发,其频率与高能量粒子的环向进动频率一致。在高β_h 区间,高能量勉强通行粒子将驱动鱼骨模进入第二稳定区。高能量捕获粒子能激发非共振鱼骨模,与勉强通行粒子激发的鱼骨模类似,在高β_h 区存在第二稳定区。     

涡流型切割磁铁的理论分析和模拟计算

从理论上推导了涡流型切割磁铁的漏场变化规律.以上海同步辐射装置(SSRF)用涡流型切割磁铁为例,进行了分析性计算和讨论,并与OPERA程序模拟计算的结果进行了比较.在此基础上,提出了降低漏场的方法和措施.     

ICP-AES法直接测定阳极泥中的金和银

使用ICP－AES法同时测定了多个阳极泥样品中的金和银。加标回收率为95．4％－103．2％,10次测定的RSD为0．8％－4．8％。方法简便,速度快,结果准确。     

低频功率超声换能器辐射声场的激光干涉检测

基于媒质的压光效应,它的折射率n是声压的函数,于是利用激光干涉技术及理论上或实验上得到的声压相对分布,可以绝对测定声场中光路上各点的声压.本文对激光干涉测量声压的原理、方法作简单介绍,给出了单面活塞辐射源中场的声压分布的理论表达式,对一增幅杆超声换能器辐射声场中的声压进行了激光干涉实验测定,并与用 PVDF换能器实测的声压分布及声压值进行比较.     

Clinical Analysis of Voice Change as a Parameter of Premenstrual Syndrome

We have evaluated the relationship between voice change and premenstrual syndrome (PMS) by comparing acoustic measurements made during the follicular phase and the premenstrual phase. Twenty-eight women were followed for 2 months for this study. Each participant was asked to produce an /a/ sound for 5 seconds at the midfollicular phase of the menstrual cycle and then 2-3 days before menstruation. Each voice sample was stored and analyzed by the Dr. Speech Science program. The voice data collected from all subjects during the two phases were compared. After that, the subjects were divided into a PMS-positive and PMS-negative group according to the criteria cited in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV); the voice data from each group were compared separately between the two phases. There was no significant difference in the acoustic parameters between the two phases in all subjects (N = 28). In the PMS-positive group (N = 16), jitter was significantly increased during the premenstrual phase compared to the follicular phase (p = 0.048). The patient's PMS score was not correlated with the severity of voice change. We conclude that the change of voice parameter was objectively identified in the PMS-positive group, therefore more careful voice habituation is required during the premenstrual phase in that group.     

KTP和7.5mol%Nb:KTP晶体在Nd:YAG激光中的倍频和和频

本文在获得精确的7.5mol%Nb:KTP晶体的Sellmeier主折射率色散方程的基础上,计算7.5mol%Nb:KTP晶体对1.0642μm和1.3188μmNd:YAG激光的倍频和和频的型相位匹配曲线.通过研究KTP和7.5mol%Nb:KTP晶体的主折射率,双折射率和相位匹配,可以看出Nb掺入KTP晶体后产生的折射率和双折射率的色散和各向异型的变化是引起KTP晶体相位变化的根本原因.     

光束成丝的非线性理论

在考虑调制场和本底场之间有能量交换的情况下,研究了小尺度调制场的非线性演化过程,结果表明,受到小尺度调制的光束在传输过程中有可能经历周期性成丝过程,通过与Bespalov-Talanov(B-T)关于成丝的线性理论比较,发现B－T理论给出的最快增长频率和临界频率等结果在非线性演化过程中仍然是适用的,但其给出的调制增长纺只在调制场的初始增长阶段与本文的非线性理论一致,此后,调制场的增长速度低于指数形式的增长速率,达到某个最大值后将经历周期性变化过程。