热对光纤中传输光的相位影响

本文首次从理论上系统地讨论了热对光纤中光波传输相位的影响,揭示出热对光波相位影响的主要的和内在的物理原因.在一定的条件下,我们还导出热对光波传输相位影响表达式.理论结果得到了实验的验证.本文结果对探索光纤应用新领域具有重要意义.     

地震模拟振动台的数控软件研究

本文介绍了笔者对单向振动台地震模拟试验软件的研究开发工作;讨论了地震模拟的数控原理。指出精确再现地震波的关健是精确地获得系统传递函数。经理论分析,用迭代法多次修正驱动信号可有效地消除系统误差,但对偶然误差效果不明显。为提高地震波再现精度必须改善模控系统的稳定性和重复性。为减小非线性误差需改进台面及支承系统特性。文中给出了编制的两种地震波再现程序及应用效果。最后介绍了控制中采用的软启动方法和为满足模型相似条件的时间压缩技术。     

液体表面张力曲面的研究

液体在各向同性的介质中,除重力以外,不受其它外力的作用,液体呈现具有特定形状的曲面。这是液体表面张力与重力平衡的结果。本文将探讨这种曲面方程与其解。     

Holographic Deformation Measurement by a Spatial Carrier Fringe Technique

A carrier fringe techrtique for measuring surface deformation is described and verified by experiments. In contrast to conventional holography and fringe analysis, this holographic system is based on fibre optics and automatic spatial carrier fringe pattem analysis techniques Single-mode optic fibres are used to transfer both the object and reference beams. Carrier fringes are generated by simply translating the object beam between two exposures The Fourier transform is applied to the carrier fringe pattern to convert it to the spatial frequency domain, where it is processed The results are given for a centrally loaded disk, including a 3-D perspective plot of the out of plane deformation field, phase map, grey level map and contour map.     

重建一维多层媒质的时域逼近法

本文提出了一种新的重建一维多层媒质的时域逼近法,并给出了若干反演的实例。     

流体饱和多孔隙介质中弹性波运动方程的解—伪谱法

本文提出了一种解流体饱和多孔隙介质中波传播方程的数值方法，并详细推导了该方法的计算公式．用此公式对单界面模型中地震波的传播进行了模拟，结果与Ｂｉｏｔ理论预测的相符．     

加速精密振动信号分析系统的数据采集

介绍一种用于进行机械振动故障监测和诊断的、由ＰＣ机和ＴＭＳ３２０１０构成的双机系统，从而使微机故障诊断系统的分析速度明显提高。     

透镜孔径限制对其傅里叶变换公式导出的影响——兼论公式使用条件

本文討论了薄透镜孔径对透镜傅里叶变换公式导出带来的困难,较全面地分析了使用该公式应滿足的条件。     

YBa2Cu3O7 ? x 240 K Phase Transition

YBa₂Cu₃O_{7 – x} ceramic samples have been investigated simultaneously by the thermal expansion and the acoustic emission methods during thermocycling through 200–300 K into liquid nitrogen steam. No jumps in the dilatation curves but change in the slope of one has been found at 228 and 234 K on heating and cooling respectively. These points are accompanied by the acoustic emission signals, a small value testifying for oxygen atoms displacement into the crystal lattice. On the basis of these measured experimental data, a thermal expansion coefficient and a specific capacity c _m have been calculated. By this c _m value an oxygen atom activation energy E = 0.15 eV has been calculated. It is shown that an isostructural oxygen-displacement second-order phase transition takes place between certain orthorhombic phases in YBa₂Cu₃O_{7 – x} near 240 K.     

Some interrelated thermophysical properties of liquid water and ice. I. A user-friendly modeling review for food high-pressure processing

A bibliographic search yielded a set of empirical equations that constitute an easy method for the calculation of some thermophysical properties of both liquid water and ice I, properties that are involved in the modeling of thermal processes in the high-pressure domain, as required in the design of new high-pressure food processes. These properties, closely interrelated in their physical derivation and experimental measurement, are specific volume, specific isobaric heat capacity, thermal expansion coefficient, and isothermal compressibility coefficient. Where no single equation was found, an alternative method for calculation is proposed. Keeping in mind the intended applications and considering the availability of both experimental data and empirical equations, the limits for the set of equations where set in -40 to 120 degrees C and 0 to 500 MPa for liquid water and -30 to 0 degrees C and 0 to 210 MPa for ice I. The equations and methods selected for each property are described and their results analyzed. Their good agreement with many existing experimental data is discussed. In addition, the routines implemented for the calculation of these properties after the described equations are made available in the public domain.