日本电视同步广播的发展和技术特性

为解决边缘地区收视困难，日本在电视广播中采用了载频偏置技术。但限于可用频道数仍无法满足更多的用户能收看６套电视节目需求，日本进一步研究并试用了电视同步广播方式，这是提高频道复用指数，解决问题干扰的有效方法。本文介绍了日本同步广播研究开发的概况及技术要点。     

非等强度,等脉冲相关技术测量甲酚紫染料的吸收恢复时间

利用非等强度、等脉冲相关技术测量甲酚紫染料吸收恢复时间。实验结果给出了甲酚紫染料吸收恢复时间为158ps。     

甲酚紫非线性光学性质的研究

报道了甲酚紫染料的非线性光学性质的实验研究方法及其结果.利用简并四波混频技术,测量得到甲酚紫甲醇溶液(浓度为5×10~(-4)M)的三阶非线性极化率X~(3)为2.0×10~(-10)esu.此外,利用不同强度皮秒脉冲相关技术得到了甲酚紫甲醇溶液的吸收恢复时间τ_(21)为163ps.     

Thermal wave photopyroelectric characterization of advanced materials: State of the art

This article reviews the history, background, theoretical basis, development, attempts to optimize, and experimental performance of the photopyroelectric technique for the optothermal characterization of advanced materials such as semiconductors, superconductors, pure metals and alloys, quantum wells, liquid crystals, paramagnetic and ferromagnetic materials, as well as solar cells. The state of the art in the experimental processes in this field is also reviewed. This new photothermal technique can be used after a careful optimization, as a highly sensitive method for photopyroelectric spectroscopy and general thermal wave measurements. It has been shown to be a highly sensitive spectroscopic method for the nondestructive evaluation of advanced materials. This review presents the main photopyroelectric theoretical models that have been used for the extraction of some important optoelectronic properties such as the optical absorption coefficient and the nonradiative quantum efficiency spectra, as well as some thermal properties such as the thermal diffusivity, thermal conductivity, and specific heat. The applicability of the general basic theoretical model with its many special cases is also described in detail. This review demonstrates how photopyroelectric spectroscopy can be complementary to the conventional spectroscopic methods. The different experimental modes of the technique are also discussed. Moreover, some ideas concerning future perspectives of applying the technique to other scientific fields are outlined. This article does not aspire to an in-depth analysis of the experimental results in the field; rather, it focuses on the technique itself.     

Vertical bridgman techniques to homogenize zinc composition of CdZnTe substrates

In order to improve the Zn homogeneity along the axial direction of CdZnTe boule, we have employed a modified Bridgman technique using a (Cd, Zn) alloy source in communication with the melt, whose temperature has been gradually changed from 800 to 840°C during growth. Electron probe microanalysis (EPMA) measurements of Zn composition in the boule shows an excellent homogeneity of Zn along the axis of the CdZnTe boule compared with results in a boule grown by using a fixed source temperature. We have performed a numerical simulation to obtain the approximate temperatures of additional heating and cooling needed to improve the radial Zn homogeneity. CdZnTe boule has been grown by seeded vertical Bridgman furnace with two zones of heater and cooler. Ultraviolet/visible spectroscopic measurements of Zn composition over the length of the boule indicate that the radial distribution of Zn composition is very homogeneous in the body region of the boule, where the radial variation of Zn composition is ±0.0005.     

植物钙调素的免疫金标记电镜技术

本文用玉米根尖作为实验材料,建立了植物钙调素免疫胶体全电镜定位技术。采用Epon812常规包埋方法;以脱脂奶粉作为封闭试剂;用过碘酸钠处理切片,使之恢复抗原性。所用的兔抗小麦钙调素抗体对植物钙调素具有较高的亲和力和专一性。本方法具有操作方便。标记特异性较强,超微结构保存较好等特点。     

粉末测试技术在探索新型有机倍频材料中的应用

一、引 盲 Davydor(1967)等研究发现,具有以下性质的物质分子,一般都有较大的二阶极化率β:(1)电子跃迁非常大;(2)伴随着跃迁,分子偶极矩会发生显著变化。而芳香族化合物分子由于     

听觉传输技术及其应用

文中综述了听觉传输技术的原理、应用和进展，在阐述了人类听觉系统对声源的定位机理后，讨论了实现听觉传输的基本原理和技术，包括双耳信号的检拾与模拟，双耳信号的扬声器重发，虚拟扬声器技术等；文中还探讨了听觉传输技术的局限性，综述了它在声学各方面的应用。文中最后还讨论了这方面今后的发展展望。     

基于开关信号理论的电流控阈技术及I^2L施密特电路

本文在开关－信号理论的指导下，采用电流信号表示逻辑值，对Ｉ＾２Ｌ电路中如何实现阈值控制进行了研究，在此基础上，提出了实现阈值控制电路的接地开关运算表示式，并用于设计相应的三值Ｉ＾２Ｌ施密持反相器电路，用ＰＳＰＩＣＥ程序模拟证明了所设计的电路具有理想的施密特电路特性。     

激光淬火与中频感应淬火对比研究

利用摩擦磨损实验机对45CrNi钢开展了激光淬火和中频感应淬火摩擦磨损对比实验研究，并利用扫描电镜(SEM)、投射电镜(TEM)和X射线衍射仪(XRD)等设备对两种淬火试样硬化层进行了微观分析。结果表明，在载荷50～250 N条件下，激光淬火试样的耐磨性比中频感应淬火试样提高了4%～21%;中频感应淬火试样的摩擦系数略大于激光淬火试样的摩擦系数。两者的主要磨损形式均为磨粒磨损，但中频感应淬火试样磨损后表面犁沟的深度和宽度大于激光淬火试样表面犁沟的深度和宽度。两种淬火方法淬硬层均为板条马氏体和少量针状马氏体的混合组织，但中频感应淬火淬硬层有大量的碳化物析出，碳化物含量多且碳化物颗粒大、残余奥氏体多。