A BOUNDARY INTEGRAL EQUATION AND ITS NUMERICAL SOLUTION OF POTENTIAL FLOW AROUND SURFACE-IRREGULA-RITIES

In this paper,using complex functional theory,the authors turn the potentialflow around the surface irregularities in a pressure conduit and semi-infinite platforms intoDirichlet problem.Based on Schwarz formula and by the application of Plemelj's formula,theauthors change the problem into the integration of a Cauchy boundary integral equation in theflow plane through the substitution of variables.Using numerical integration,the authors obtainthe velocity distribution and pressure coefficient along surface irregularities and platforms.Thephysical concept of this method is clear,the convergent speed is rapid and the computative effi-ciency is high.The calculated values agree well with the measured results.It is an effective andsimple method in solving potential flow.     

RH-KTB耐材长寿技术研究及应用

介绍了宝钢RH-KTB工艺条件下RH用镁铬砖的应用和提高浸渍管管龄、下部槽槽龄的方法.     

Optical phase conjugation of multiwavelength signals in adispersion-shifted fiber

Optical phase conjugation (OPC) of multiwavelength signals in a dispersion-shifted fiber (DSF), which can be used for dispersion compensation in the wavelength division multiplexing communication system, is theoretically studied. The multiwavelength phase-conjugate signals are generated by four-wave mixing (FWM) in the dispersion-shifted fiber. There are the pulse-shape distortion and the induced frequency chirping in the phase-conjugate signals owing to pump depletion and the cross-phase modulation among the signals and phase-conjugate signals, respectively. The FWM among the pump wave, signals, and phase-conjugate signals causes unequal conversion efficiencies for the multiwavelength signals and enhances the induced frequency chirping in the phase-conjugate signals. The induced frequency chirping may deteriorate the restoration of the pulse shape. Both the pulse-shape distortion and induced frequency chirping increase with the signal and pump powers. The formula for the induced frequency chirping that is only caused by the signals through cross-phase modulation is derived. The requirement of the signal power in the dispersion-shifted fiber for the restoration of the pulse shape by the optical phase conjugation is estimated and numerically verified     

大断面交岔点失稳分析及治理

通过工程地质调查、室内围岩物化分析和力学试验 ,深入研究了围岩变形力学机制和破坏机理 .根据新奥法施工原理 ,采取了有针对性的综合治理措施 ,将围岩复杂的变形力学机制转化为单一的变形力学机制 ,使该工程得到了有效治理 .取得的技术经验推广应用于该矿井其它失稳破坏工程 ,均获得了圆满成功     

MMDS技术综述

本文介绍多点多频道电视信号开路分配服务系统,并简述了传输接收技术。     

Synthesis and characterization of novel copolymers with the trimethylsilyl group for deep‐UV photoresists

N‐(4‐Acetoxyphenyl) maleimide (APMI) and three kinds of comonomers bearing a trimethylsilyl group were copolymerized at 60°C in the presence of azobisisobutyronitrile (AIBN) as an initiator in 1,4‐dioxane to obtain the three IP, IIP, and IIIP copolymers. These copolymers were removed from the acetoxy group in a transesterification process into new IVP, VP, and VIP copolymers with a pendant hydroxyl group. Two modified processes were adopted to prepare photoresists using these copolymers. The first process involved mixing the dissolution inhibitor, o‐nitrobenzyl cholate, with the new copolymers. Second, o‐nitrobenzyl cholate was introduced into the copolymers using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in dimethylformamide (DMF). The cyclic maleimide structure is responsible for the high thermal stability of these copolymers. After irradiation using deep–UV light and development with aqueous Na₂CO₃ (0.01 wt %), the developed patterns showed positive images and exhibited good adhesion to the silicon wafer without using any adhesion promoter. The resolution of these resists was at least 0.8 μm and an oxygen‐plasma etching rate was 1/5.3 to that of hard‐baked HPR‐204. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2791–2798, 2002; DOI 10.1002/app.10255     

皮革真空鞣制新技术与设备的研究

本文对皮革在真空状态下鞣制进行了试验研究，使鞣制过程的物理—化学氛围得到改善，大大缩短了鞣制时间，废液排放量减少一半以上。     

氢/空气火焰在半开口有障碍管道中的传播特性

针对氢／空气混合物，通过实验研究了其预混火焰在半开口管道中的火焰传播加速现象。结果表明，火焰传播状态随着氢气当量比的变化而发生改变。当氢／空气混合物被点燃后，由于障碍物的扰动，火焰在管道中不断加速传播，并最终到达一准稳态传播。在氢气当量比0．34附近时，火焰速度发生跃变。当氢气当量比足够大时，火焰传播由爆燃态转变为爆轰态。在本实验条件下，爆燃转准爆轰的临界条件是d/λ=2.6(d是圆环形障碍物内径，λ是爆轰格胞尺度）。障碍物阻塞比的变化对最大火焰速度和压力提升的影响不明显。     

DX型数据采集与无线传输系统

DX型数据采集与无线传输系统能对油井压力、温度、载荷和流量等参数进行自动采集 ,并通过无线传输向总站提供实时参数 ,为及时决策提供信息。数据采集系统采用STD总线 ,测量精度高、故障低 ;无线传输系统采用短波电台和具有自动纠错功能的数传机 ,抗噪能力强、可靠性高。文章介绍了DX型数据采集与无线传输系统的组成、工作原理、功能和主要技术指标     

基于精细积分法的干摩擦隔振系统稳定性的研究

本文利用摩擦隔振系统的计算模型，建立了系统的动力学方程，在此基础上，对干摩擦隔振系统的稳定性问题进行了分析，同时将精细积分法引入了求解过程，提高了计算的精度，并给出了相应的数值例题，本文的工作可为工程应用提供必要的计算依据。