精密相位激光测距仪的设计

本文在论述了精密相位激光测距的理论依据的基础上，着重对系统设计中的误差进行了较为深入的分析与讨论，并据此提出了小型相位式激光测距仪的设计方案及相位鉴别与统计处理的方法，最后进一步给出了提高系统精度的修正措施。     

UWB技术在有线电视网中的应用

起宽带(Ultra Wideband，UWB)技术是近几年发展起来的一项十分有潜力的无线通信技术，以其高性能、低成本的无线数据通信能力，成为实现无线个人局域网的富有竞争力的技术之一。依据起宽带技术的主要特点，讨论了该技术在有线电视网中应用的优势及其实现，这不仅为解决有线电视网带宽“瓶颈”问题提供了有效的方案，也使UWB技术得到了更广泛的应用。     

Microwave preheating of anisotropic conductive adhesive films for high-speed flip chip on flex bonding

Anisotropic conductive adhesive film (ACF) can be preheated by microwave (MW) radiation in order to reduce the bonding time for flip-chip technology. Due to sluggish and nonuniform curing kinetics at the beginning of the curing reaction, thermal curing of epoxy is more time consuming. Therefore, MW radiation may be more effective, due to its uniform heating rate during the cycle. In this paper, MW preheating (for 1–4 sec) of ACF prior to final bonding has been applied to determine the electrical and mechanical performance of the bond. Powers of 80 and 240 W MW were used to study the effect of the MW preheating. A final bonding time of 6–7 sec can be used for flip chip on flex bonding instead of 10–15 sec (standard time for flip chip bonding) for MW preheating time and power used in this study. The contact resistance (as low as 0.01) is low in these samples, whereas the standard resistance is 0.017 ohm (bonded at 180°C for 10 sec without prior MW preheating). The shear forces at breakage were satisfactory (0.167–0.183 KN) for the samples bonded for 6–7 sec with MW preheating. This is very close and even higher than the standard sample (0.173 KN). For MW preheating power of 80 W and sweeping time of 2 sec, final bonding at 6 sec can also be used because of its low contact resistance (0.019 ohm). Scanning electron microscope (SEM) investigation of microjoints and fracture surface shows uneven distribution of conductive particles and thick bond lines in samples bonded for 5 sec (with MW preheating). Samples treated with MW radiation (80 W and 2–3 sec time) serve as evidence that well-distributed particles along with thin bond lines cause low contact resistance and high joint strength.     

皮秒脉冲在色散缓变光纤中的孤子效应压缩

本文给出了描述皮秒脉冲在色散缓变单模光纤中孤子效应压缩过程的数学模型。通过数值求解，首次对该孤子效应压缩进行了全面的计算和分析。结果表明，与常规光纤相比，采用色散缓变程度合适的光纤压缩皮秒脉冲，不仅能显著地提高压缩后脉冲的峰值功率和脉冲压缩比，而且能有效地消除压缩后脉冲的次峰和脉座。对于确定的脉冲输入，发现，当光纤的色散缓变程度取某一最佳值时，能获得最佳的压缩效果。进一步研究表明，色散的这一最佳变     

相对论磁控管的实验研究

简要分析了相３对论磁控管的主要特点与问题，编制了谐振系统数值计算程序，通过数值计算与冷测，对不同阴极尺寸与输出结构的磁控管进行了研究，清晰地描述了磁控管的振荡模式与简并现象。制作了Ａ６型相对论磁控管并进行了热测实验，研究了输出功率与工作磁场的关系，经过大量优化工作，在Ｓ波段获得了３８０ＭＷ的微波辐射。     

Three-dimensional ab initio dipole moment surfaces and stretching vibrational band intensities of the XH3 molecules

Stretching vibrational band intensities of XH₃ (X=N, Sb) molecules are investigated employing three-dimensional dipole moment surfaces combined with the local mode Hamiltonian model.The dipole moment surfaces of NH₃ and SbH₃ are calculated with the density functional theory and at the correlated MP2 level,respectively. The calculated band intensities are in good agreement with the available experimental data. The contribution to the band intensities from the different terms in the polynomial expansion of the dipole moments of four group V hydrides (NH₃, PH₃,AsH₃ and SbH₃) are discussed. It is concluded that the breakdown of the bond dipole approximation must be considered. The intensity “borrowing” effect due to the wave function mixing among the stretching vibrational states is found to be less significant for the molecules that reach the local mode limit.     

Numerical Simulation of Pulse Shortening in RBWOs

Pulse shortening hinders improvement of microwave output energy for high power microwave tubes. So far, it is also an unresolved problem in the field of high power microwave devices.In this paper, relativistic backward wave tube (RBWO) is treated as an example to study the pulse shortening phenomena. The influences of gas existing in the tube and explosive emission in inner surface of RBWO are all investigated by means of the particle-in-cell method. Through the simulation results, it can be predicted that the background gas in the tube is one but not the most important factor resulting in pulse shortening, in order to broaden the pulse width of gas-filled RBWO, the pressure of the filled gas must be controlled in a proper value. The explosive emission in the surface of slow wave structure due to intense electric field is one of the most important factors causing pulse shortening in high power microwave tube.Some methods to overcome this kind of explosive emission are also given.     

NONDESTRUCTIVE BAND—GAP PROFILE DETERMINATION OF HgCdTe LPE CROWN LAYERS

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