浅谈电动机的故障检查与维护

针对电动机出现的故障检查与维护,从日常检查、电动机具体项目检查、电动机启动前后检查、常见的故障与处理等方面进行了论述。     

论信息环境变化下的高校图书馆信息服务工作

论述当前信息环境变化的新特点，分析这一变化给高校图书馆信息服务工作带来的新要求和新问题，并针对这些新问题，提出改进信息服务工作的新举措。     

一种电子商务税收征管系统模型的研究

探讨了网上交易的过程,给出了一个基于SET协议和CA认证的税收征管方案．     

浮钳盘式制动器的有限元分析

通过对浮钳式盘式制动器的受力分析，建立了其关键部件钳体和支架的力学模型。应用大型机械CAD／CAE／CAM软件Ⅰ—DEAS对某一国产的浮钳式盘式制动器进行了有限元建模和分析，求解它们在工作状态下的应力情况。结果表明，钳体和支架的设计强度满足材料性能要求，该制动器的设计是成功的。     

A new method to dynamically simulate groundwater table in land surface model VIC

Soil moisture plays an important role in water and energy balance in land-atmospheric interaction, but is impacted directly by the groundwater table. Dynamic variation of the groundwater table can be described mathematically by a moving boundary problem. In this paper, the moving boundary problem is reduced to a fixed boundary problem through a coordinate transformation. A new model of groundwater table simulation is developed using the mass-lumped finite element method and is coupled with the land surface model of Variable Infiltration Capacity (VIC). The simulation results show that the new model not only can simulate the groundwater table dynamically, but also can evade the choice of water table depth scale in computation with a low computation cost.     

Multisymplectic five-point scheme for the nonlinear wave equation

In this paper, we introduce the multisymplectic structure of the nonlinear wave equation, and prove that the classical five-point scheme for the equation is multisymplectic. Numerical simulations of this multisymplectic scheme on highly oscillatory waves of the nonlinear Klein-Gordon equation and the collisions between kink and anti-kink solitons of the sine-Gordon equation are also provided. The multisymplectic schemes do not need to discrete PDEs in the space first as the symplectic schemes do and preserve not only the geometric structure of the PDEs accurately, but also their first integrals approximately such as the energy, the momentum and so on. Thus the multisymplectic schemes have better numerical stability and long-time numerical behavior than the energy-conserving scheme and the symplectic scheme.     

Abnormal piezoresponse behavior of Pb（Mg1／3Nb2／3）O3-30% PbTiO3 single crystal studied by high vacuum scanning force microscopy

The piezoresponse behavior dependence of the Pb(Mg1/3Nb2/3)O3-30%PbTi03 single crystal on the vacuum degree has been investigated by scanning force microscopy in the piezoresponse mode under high vacuum. Unusual piezoresponse behavior related to the screening charges compensation mechanism is observed on the (111) crystal face. The significant piezoresponse degradation behavior with low piezoresponse signal under high vacuum is attributed to the instability of the polarization state due to the insufficient compensation of the intrinsic screening charges for the polarization charges in PMN-30%PT single crystal. In contrast, the remarkable domain contrast of the sample at ambient pressure is owing to the dominant surface screening charges deriving from surface adsorption, which plays an important role in determining the stability of the domain behavior and in achieving the optimal properties.     

Time-division phase modulated single-photon interference in a Sagnac interferometer

We introduce a stable, long-distance singlephoton Sagnac interferometer, which has a balanced configuration to efficiently compensate phase drift caused by change of the fiber-optic path. By using time-division phase modulation, single-photon interference was realized at 1550nm in a 5-km-long as well as 27-km-long Sagnac fiber loops,with a fringe visibility higher than 90% and long-term stability. The stable performance of the single-photon interference indicated that the time-division phase-modulated Sagnac interferometer might readily lead to practical applications in single-photon routing and quantum cryptography.     

面向装配的三维标准件库研制

在分析产品装配特征和国内外标准件建库技术的基础上，根据并行工程中装配建模的需要，提出了面向装配的三维标准件库的一般原则，给出标准件库的基本框架和关键技术解决方案，并且结合实例加以说明．     

区间值模糊集合的表现定理

针对区间值模糊集合，给出了2类区间值集合套的定义，得到了2个区间值模糊集合的表现定理。