表面约束稳态装置中高频离子声波的激发特性     

袁定朴  杨宣宗 《核聚变与等离子体物理》1993,13(3):38-42

高频离子声波由于Landau阻尼很大,一般难以激发。本文研究了表面约束稳态装置上高频离子声波的激发特性。实验表明,仔细控制放电参数可以激发起纯离子声波,密度涨落n/n_o最大可以达到7.5％。  相似文献   

关于泛球面上散射波求解的综述     

《数理译丛》1993,(2):1-6

  相似文献   

磁场引导声波“点燃”太阳光环     

《物理通报》2007,(6):43-43

2007年5月29日的美国天文学会第210次会议上公布的一项最新研究结果，揭开了太阳表面的红色光环——色球（chromosphere）的形成机制和能量来源．  相似文献   

柱状分层固体媒质的声散射     

王耀俊 《物理学进展》2003,23(2):125-144

本文评述了各向同性和横向各向同性柱状分层固体声散射理论和实验研究进展介绍了描述圆柱状界面薄层特性的弹簧模型，也讨论了该领域中有待进一步研究的一些问题。  相似文献   

一种新型的表面声波阻抗传感器及其在液相体系中的应用     

姚守拙  陈康 《高等学校化学学报》1994,15(4):507-508

一种新型的表面声波阻抗传感器及其在液相体系中的应用姚守拙，陈康，刘德忠，聂利华（湖南大学化学化工系，长沙，４１００８２）关键词表面声波，阻抗传感器，液相应用表面声波传感器（ＳＡＷＳ）具有较高的灵敏度和检测精度，已广泛应用于气体微量组分分析、色谱检测和...  相似文献   

气相色谱-表面声波快速分析仪性能评价     

朱佐刚  李顺洲  胡玢  赵寿堂  何世堂 《分析科学学报》2010,26(3)

本文评价了自行研制的气相色谱-表面声波(GC-SAW)联用快速分析仪的性能。实验结果表明:在6 s以内,GC-SAW快速分析仪能分离五种苯系物和C6~C14九种正构烷烃。该仪器对甲苯测定的相对标准偏差(RSD)为2.5%(n=6);最小检出浓度为2.05μg.L-3;线性范围为2.05~205μg.L-3;对标准样品连续6次分析,经双边t检验,分析结果均值与标样标准值无显著差异。  相似文献   

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杨天应  蒋书文  李汝冠  姜斌 《中国物理 B》2012,21(10):106801-106801

Tunable and switchable Ba 0.5 Sr 0.5 TiO 3 film bulk acoustic resonators（FBARs） based on SiO 2 /Mo Bragg reflectors are explored,which can withstand high temperature for the deposition of Ba x Sr 1 x TiO 3（BST） films at 800 C.The dc bias-dependent resonance may be attributed to the piezoelectricity of the BST film induced by an electrostrictive effect.The series resonant frequency is strongly dc bias-dependent and shifts downwards with dc bias increasing,while the parallel resonant frequency is only weakly dc bias-dependent and slightly shifts upwards at low dc bias（ 45 V） while downwards at higher dc bias.The calculated relative tunability of shifts at series resonance frequency is around 2.3% and the electromechanical coupling coefficient is up to approximately 8.09% at 60-V dc bias,which can be comparable to AlN FBARs.This suggests that a high-quality tunable BST FBAR device can be achieved through the use of molybdenum（Mo） as the high acoustic impedance layer in a Bragg reflector,which not only provides excellent acoustic isolation from the substrate,but also improves the crystallinity of BST films withstanding higher deposition temperature.  相似文献   

Modulational instability of ion—acoustic waves in a warm plasma          下载免费PDF全文

薛具奎  段文山  郎和 《中国物理》2002,11(11):1184-1187

Using the standard reductive perturbation technique,a nonlinear Schroedinger equation is derived to study the modulational instability of finite-amplitude ion-acoustic waves in a non-magnetized warm plasma.It is found that the inclusion of ion temperature in the equation modifies the nature of the ion-acoustic wave stability and the soliton stuctures.The effects of ion plasma temperature on the modulational stability and ion-acoustic wave properties are inestigated in detail.  相似文献   

多芯光纤分布式声传感     

顾金凤  卢斌  杨竣淇  王照勇  叶蕾  叶青  瞿荣辉  蔡海文 《光学学报》2021,41(7):21-28

多芯光纤中有多个独立并行的空间信道,利用其实现空间分集,以解决基于传统单模光纤的分布式光纤声波传感系统所面临的信号衰落和信噪比受限问题.通过扇入扇出模块,在多芯光纤的其中四个纤芯中进行信号的独立传输和分集探测,并采用相干合并技术对多路信号进行有效合并.实验结果表明,外部扰动信号得到了很好的重构,信号衰落被抑制,系统的底...  相似文献   

Spectral analysis of the UFBG-based acousto optical modulator in V–I transmission matrix formalism          下载免费PDF全文

吴良英  裴丽  刘超  王一群  翁思俊  王建帅 《中国物理 B》2014,(11):251-256

In this study, the V-I transmission matrix formalism （V-I method） is proposed to analyze the spectrum characteristics of the uniform fiber Bragg grating （FBG）-based acousto--opfic modulators （UFBG-AOM）. The simulation results demon- strate that both the amplitude of the acoustically induced strain and the frequency of the acoustic wave （AW） have an effect on the spectrum. Additionally, the wavelength spacing between the primary reflectivity peak and the secondary reflectivity peak is proportional to the acoustic frequency with the ratio 0.1425 nm/MHz. Meanwhile, we compare the amount of calculation. For the FBG whose period is M, the calculation of the V-I method is 4 × （2M-l） in addition/subtraction, 8 × （2M - 1） in multiply/division and 2M in exponent arithmetic, which is almost a quarter of the multi-film method and transfer matrix （TM） method. The detailed analysis indicates that, compared with the conventional multi-film method and transfer matrix （TM） method, the V-I method is faster and less complex.  相似文献