MOVPE生产用高纯水中硅的去除

本文介绍了硅对砷化镓材料生长及有机金属化合物气相淀积(MOVPE)工艺中的影响和电脱盐(EDI)技术以及用EDI降低高纯水中硅浓度的机理和方法,通过大量实验比较不同制水设备脱硅效果,得出用EDI技术严格控制pH(8~11)时脱硅效果最好,能使高纯水中Si的浓度＜0.5μg/L,满足了MO源生产及MOVPE工艺用水中Si浓度<3μg/L的需要.     

Synthesis of Highly Branched Poly（ε-caprolactone） by Self-condensing Atom Transfer Radical Polymerization of Macroinimers

Fréchet et al.1 in 1995 prepared hyperbranched vinyl polymers by the technique named self-condensing vinyl polymerization (SCVP) of initiator-monomers (“inimers”) having the general structure AB*, where A stands for a double bond and B* for an initiati…     

Polarization-preserved and polarization-rotated synchronization of chaotic vertical-cavity surface-emitting lasers

The synchronization process in a vertical-cavity surface-emitting laser (VCSEL) based master-slave configuration, where the master laser has been destabilised by optical feedback from an external mirror, has been investigated. The dynamics of both VCSEL polarization modes have been modeled and used to study the chaos synchronization mechanism in both polarization preserved, and polarization rotated unidirectionally coupled master and slave configurations. Two types of synchronization have been identified in the polarization rotated case, one of which may afford an opportunity to effect multiplexed message encoding using orthogonal laser modes.     

活性炭分离-桑色素荧光法测定天然水中痕量铍

在溴化十四烷基吡啶存在下,铬天菁S与铍生成三元胶束络合物。在pH10.0氨～氯化铵缓冲介质中,活性炭定量吸附此络合物,用热盐酸洗脱铍,可与其他干扰离子分离,用桑色素荧光法进行测定。该法用于测定美国EPA标准水样和天然水中的痕量铍,结果令人满意。     

罗兰C信号传播中的ASF修正方法

罗兰C信号在传播过程中受到陆地导电率和地形等因素的影响,传播速度不可预测,使信号传播时延增加,引起附加二次相位因子(ASF),降低了接收机的定位精度,因此在精确定位解算之前,需要用ASF对实测的罗兰传播时延进行修正。介绍了采取时间比对方法,利用现场实测和理论预测相结合建立起ASF修正数据库,提供给用户使用,解决ASF修正问题,使定位准确度得到有效改善。     

Dynamics of laser-induced shock wave by optical probe in air

A new simple optical system based on optical beam deflection combining the holophote corner cube was developed in order to study the dynamics of laser-induced shock waves in air. In this method, we adopt a He-Ne laser beam as the detection beam. The He-Ne laser beam, reflected by corner cube, intersects the propagating shock wave at two successive positions. The measurement of the shock wave velocity benefits from the double peak signals induced by the same acting laser pulse, which is calculated from the time interval between the corresponding oscilloscope signals and the distance of the two He-Ne laser beams. By virtue of this setup, we are also able to determine the pressure of the generated shock waves. It is shown that this method is simple with a fairly good precision and is much easier than the conventional methods used for this task.     

洗牌型光电混合神经网络实验系统

在研究洗牌网局部互连光学实现问题的基础上 ,采用洗牌型图样间联想模型建立了具有完整的加权互连、求和、非线性处理及反馈功能的光电混合神经网络实验系统 ,进行了 8× 8数字样本的光学联想识别。实验结果证实了洗牌网理论的可行性和洗牌型图样间联想模型光学实现的优越性     

适用于稀疏信道的MVA算法

主要介绍了一种适用于稀疏信道的复杂度可大大降低的Viterbi均衡算法。在本算法中,计算的复杂度并不依赖于信道冲激响应的长度,而是依赖于信道冲激响应中非零系数的数目。仿真结果表明,在稀疏信道下,此算法具有良好的性能,它不仅适用于最小相位系统,也适用于非最小相位系统。     

浅析液态铝电解电容器的失效机理及可靠性

简述了液态铝电解电容器的结构与制造工艺流程,归总了其失效模式。从制程和应用两个方面﹐探讨了液态铝电解电容器的失效机理及导致原因。使用环境温度及纹波电流是影响液态铝电解电容器寿命的主要因素,文中阐述了温度及纹波电流影响寿命的机制。应用Arrhenius方程的形式描述了液态铝电解电容器的寿命估算方法。     

遗传算法在波导裂缝阵列天线设计中的应用

本文采用遗传算法分两步优化矩形波导裂缝天线阵,首先对天线阵元激励幅值进行了初步优化,直接利用可分离型分布,大大简化了初步设计的过程,并将阵元激励幅值比值作为优化参量以利于波导结构的馈电;在随后进行的波导裂缝阵列阵元的偏置量和缝隙长度的优化上动态处理阵元的互耦并结合Elliott设计思想,采用遗传算法得出的3cm(1×4)缝阵结果验证了GA算法的有效性和准确性,并完成了72元矩形波导裂缝阵列的阵面优化,为大中型阵列优化提供了一种有效的方法.