硅微机械梳齿静电谐振器的建模与分析

基于参数化的计算机辅助设计（CAD）软件，对硅微机械梳齿静电谐振器进行了实体建模，以有限元分析软件为工具，进行了谐振器的模态分析，静态分析和谐响应分析，初步揭示了谐振器的静、动态特性，有助于改善设计效率和质量，展示了计算机辅助工程（CAE）技术在微机电系统（MEMS）研究中的重要作用。     

微波介质谐振器介电参数的测量

本文讨论了微波介质谐振器介电参数测试技术。用研制的测试装置对多个介质样品进行了实测，结果表明，本文的分析与实际值是吻合的。该测试技术可对微波介质谐振器的复介电常数进行迅速、准确、可靠、宽频带、无损伤、自动化和批量检测，具有较强的实用性。     

高功率板条固体激光器研究的进展

本文对高功率板条固体激光器研究的进展和应用前景作了综合评述。结合作者部分工作,对板条激光器的热效应、聚光器和光学谐振腔等关键问题和技术进行了物理分析。     

高功率固体激光器

本文详细讨论了设计高平均功率固体激光器的有关问题,包括激光材料性质、棒状和板条状几何结构,聚光器和光学谐振腔等。分析表明,板条状几何结构固体激光器提供了达到千瓦级功率水平同时又保持良好光束质量的可能性。     

A novel direct aerodynamically assisted threading methodology for generating biologically viable microthreads encapsulating living primary cells

In a recent discovery, coaxial electrospinning was explored to encapsulate living organisms within a continuous bio‐polymeric microthread from which active biological scaffolds were fabricated (Townsend‐Nicholson and Jayasinghe, Biomacromolecules 2006, 7, 3364). The cells were demonstrated to have gone through all expected cellular activity without their viability being compromised. These biologically active threads and scaffolds have direct and tremendous applicability from regenerative to therapeutic medicine. Currently these post‐processed cells as composite threads and scaffolds are being investigated in‐depth at a cellular level to establish if the processing methodology has any affect on the cellular make‐up. We now demonstrate a competing non‐electric field driven approach for fabricating composite threads and scaffolds influenced only by a differential pressure. We refer to this novel composite thread to scaffold fabrication methodology as coaxial aerodynamically assisted bio‐threading (CAABT). Our investigations firstly, demonstrate that this technique can process handle living organisms without biologically perturbing them in anyway. Secondly the process is elucidated as possessing the ability to form composite active threads from which biologically viable scaffolds are formed. Finally our study employs florescent activated cell sorting (FACScan), a method by which the cellular dynamics and viability are quantified on control and threaded cellular samples at two prescribed time points. In parallel with FACScan, optical comparison of cellular morphology at three time points within a period of three weeks is carried out to photographically observe any changes in the post‐processed cellular phenotype. Our developmental investigations into this novel aerodynamically assisted threading methodology has unearthed a unique biomicrofabrication approach, which joins cell electrospinning in the cell threading to scaffold fabrication endeavor. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Optically tuned superconductive-dielectric resonators with whispering-gallery modes

An analytical method is presented for calculating the resonant frequency andQ-factor of a superconducting dielectric disk resonator operating in millimeter-wave regime with whispering-gallery mode. Resonant frequency shift due to the optical generation of quasi-particles in superconducting film is investigated as a function of photon flux. An optically tunable resonant frequency of about 500 MHz is estimated, and good agreement is found between numerical results and experimental ones.     

Sound-velocity measurements for HFC-134a and HFC-152a with a spherical resonator

A spherical acoustic resonator was developed for measuring sound velocities in the gaseous phase and ideal-gas specific heats for new refrigerants. The radius of the spherical resonator, being about 5 cm, was determined by measuring sound velocities in gaseous argon at temperatures from 273 to 348 K and pressures up to 240 kPa. The measurements of 23 sound velocities in gaseous HFC-134a (1,1,1,2-tetrafluoroethane) at temperatures of 273 and 298 K and pressures from 10 to 250 kPa agree well with the measurements of Goodwin and Moldover. In addition, 92 sound velocities in gaseous HFC-152a (1,1-difluoroethane) with an accuracy of ±0.01% were measured at temperatures from 273 to 348 K and pressures up to 250 kPa. The ideal-gas specific heats as well as the second acoustic virial coefficients have been obtained for both these important alternative refrigerants. The second virial coefficients for HFC-152a derived from the present sound velocity measurements agree extremely well with the reported second virial coefficient values obtained with a Burnett apparatus.Paper dedicated to Professor Joseph Kestin.     

短开路耦合谐振器加载的宽带带通滤波电路

提出了一种基于短开路耦合器加载的宽带带通滤波电路. 该滤波电路通过在输入和输出端口之间,并连加载短路耦合微带谐振器和开路耦合微带谐振器实现5个传输极点和3个传输零点的带通选择特性. 对所提出的短开路耦合谐振器进行了奇偶模理论分析,揭示了其传输零极点形成的物理机理. 最后,对所提出的滤波电路进行了加工测试. 测试结果表明,所提出的宽带滤波电路能够在2.0～4.2 GHz频率范围内实现 3 dB 带通传输,工作相对带宽为73%,仿真和实测结果吻合较好.     

针对通过噪声的空滤器声学特性研究与改进

通过实验方法分析研究了一种中型乘用车通过噪声的特性,比较该车进、排气两侧通过噪声的声级和频谱特性,确定了进气噪声对车辆进气侧通过噪声的重要影响.为了解决该车进气噪声的问题从而达到整车降噪的目的,应用实验与边界元法计算两种手段,对该车空滤器的频率响应特性进行了研究.研究发现空滤器声系统的第一阶声固有频率与进气噪声基频相耦合是造成该车辆进气侧通过噪声高于排气侧的重要原因.基于这一研究结果,在计算和实验的基础上利用Helmholtz共振腔对空滤器的声学特性进行了改进,改进后的空滤器对降低车辆进气侧通过噪声有很好的作用.     

基于MEMS声传感器的圆柱壳体振动陀螺振型检测技术

振动陀螺谐振子振型一般采用激光进行非接触式测量,这种方法存在设备成本高、操作复杂、效率低等问题,因此,提出了一种基于MEMS声传感器的圆柱壳体振动陀螺谐振子振型测试方法。该方法利用体积小,指向性高的MEMS声传感器对谐振子振动声场进行高分辨率测量,获得精确的谐振子振动分布情况,建立了谐振子声波测试实验系统,进行了测试实验,并与激光测振仪的测量结果进行比对。实验结果表明,该测试系统具有较高的振型测量精度。这种测试方法成本低,操作简便,测量精度高,可以实现谐振子振型的高精度快速测量,为后续的谐振子修形及陀螺控制提供重要基础。