自由装填增面药柱燃烧规律射线成像技术研究

通过X射线高速实时成像技术(Real Time Radiography,RTR)对自由装填增面药柱(单根药柱及多根药柱)的燃烧规律进行了试验研究,包括药柱的不同燃面同时点燃特性、燃烧终止前药柱结构状态、自由装填药柱混合燃烧特性,并通过建立压力与燃面几何关系,得到燃速公式,与采用标准燃速测定方式测得的结果进行对比分析。试验结果表明:该种方法用于测定药柱燃速方法有效,对药柱燃烧规律的研究具有重要意义。     

Piecewise constant strain kinematic model of externally loaded concentric tube robots

This paper presents a piecewise constant strain kinematic model for concentric tube robots (CTR) in externally loaded conditions. It discretizes the pre-curved tubes comprising the robot into a finite number of pieces and involves external effects as a set of wrench vectors exerted along the robot backbone. Constant strain lets us describe the pieces with helices in which shear deformation and elongation are neglected. The resulting piecewise helix is the simplest curve that can catch the torsion of tubes that play a crucial role in kinematic behavior. This approximation transforms the conventional boundary value problem (BVP) of CTRs models into a set of nonlinear equations that drastically decreases the model resolution time. The present method uses a Lyapunov function and torsional Jacobian to ensure the distal torsion constraint consistently and, as a result, the solution’s convergence. The paper’s primary purpose is to present a fast, numerically stable, and relatively accurate kinematic model not reliant on measurement data. Experimental results on a two-tube prototype and provided for different tip loading conditions reveal maintaining a balance between adequate accuracy and reasonable running time, about 7 ms for five pieces per section, for real-time applications in the presence of external load.     

冲击作用下多元石英计压电电流研究

对一种多元石英计的冲击动态响应进行了实验研究，实验结果表明，冲击压力低于2GPa的条件下，多元石英计测量单元压电电流动态响应的基本特征，以及在边缘效应影响下，测量单元压电电流起跳值的降低、斜升幅度的增加，都类似于短路型单元石英计，因而可应用于冲击作用，特别是空间非均匀冲击作用分布等的研究。     

扩散炉自动上下料系统安全性设计

介绍了一种用于卧式扩散炉的自动上下料系统,对自动上下料系统组成进行了介绍,着重讨论了系统的安全性问题,并对安全性提出了解决方案,该系统控制效果良好,能为电池片生产企业降低人工成本,提高生产效率,增强了设备的安全性,适合大规模电池片生产要求。     

风载荷对阵列天线外形设计的影响

本文概述了风载荷对阵列天线外形设计的影响,比较了几种天线外形设计在风洞试验中的数据,并讨论了其实际应用。     

液体介质中厚度切变石英晶体传感器的特征阻尼研究

本文提出一个新概念：特征阻尼系数ｋｃ。用来区分液体中振荡的厚度切变石英晶体传感器由质量负载和液体阻尼分别引起的频率偏移。理论推导表明，当石英晶体表面附着的质量没有变化时，特征阻尼系数Ｋｃ０的大小与附着的液体或固体性质无关，只取决于晶体谐振器自身的参数，如基频、电极面积和谐波次数等。     

测控电路设计中运算放大器的若干误用

运算放大器(运放)在测控电路中有重要而广泛的应用,已成为测控电路中的基本器件.测控电路的特点对运放的应用设计有更高的要求.在测控电路设计中,往往因运放的应用设计不当或错误而降低电路的性能,甚至电路不能正常工作.总结了在测控电路设计中运放的几种重要误用,分析了其原因,并给出了相应的对策.相关的讨论与结论对运放在测控电路中的应用设计具有参考作用.     

Cognitive Radio Dynamic Access Techniques

The ever growing demand for wireless services has placed enormous burden on valuable resources such as spectral bandwidth. This has resulted in a major rethinking in resource allocation policies culminating in an explosion of research activity in the field of Cognitive Radio (CR) towards optimum resource usage. In this tutorial paper the physical layer design and transmission techniques for CR in the context of efficient spectrum utilization are discussed. Spectrum sensing as the key element of CR awareness is described. Orthogonal frequency division multiplexing (OFDM) as a spectrally efficient modulation scheme is discussed and the rationale for its use in the CR system is explained. Spectrum pooling for efficient use of spectrum is studied and the role of adaptive OFDM techniques in this method is highlighted. Wavelet basis function as a replacement of Fourier transform in OFDM is evaluated. MIMO system as an added value to the CR performance is described. Adaptive Waveform and beamforming as alternative techniques in CR are reviewed.

基于虚拟仪器的变速箱加载综合实验台的研究

针对传统变速箱试验台检测精度低、能量消耗大、成本高、只能恒载荷加载的不足之处,提出了新颖节能的“交流发电,直流回馈”电封闭变速箱加载综合试验台。引入虚拟仪器技术对试验台进行自动监控与管理,实现试验台的远程测控。在检测技术的基础上将电封闭式节能加载技术、模糊控制技术与虚拟仪器技术相结合,致力于开发新型变速箱加载综合试验台,对变速箱进行综合性能测试。     

Y型双声路声表面波质量传感器及其测量系统

报道了一种在128°Y切割X传播方向的LiNbO3基片上设计并研制新型的延迟线型声表面波质量传感器及测量系统。由于环境温度对声表面波质量传感器性能影响较大,因此采用新型的Y型双声路结构克服环境温度对传感器性能的影响。阐述了Y型双声路质量传感器器件的结构及设计、测试电路的原理,对实验结果作了分析讨论。测试结果表明:器件相对温度系数仅为11Hz/°C左右,器件的质量沉积效应灵敏度为3.62GHz·cm2/g,并且具有良好的线性度。