基于状态空间法的电动机故障诊断和识别

电动机的初期故障信号一般较弱,不易辨别,而状态空间法在小信号的处理中灵敏度很高。为达到对电动机故障的诊断和识别,试图把状态空间法应用到对电动机的故障诊断中,先通过推导,从数学理论层面分析了状态空间法对于电动机故障信号的可辨别性,再使用Matlab软件搭建状态空间的辨别模型,把实验台测试的三组数据导入到模型中进行测试。测试的结果有力地证明了此方法的可行性,并能克服快速傅里叶变换(FFT)中数据采集量较大、分辨率不高的缺点。     

在协议集成测试系统上开展路由协议测试

在分析路由协议的特性及其测试需求的基础上，提出利用窗口黑盒来描述被测协议，利用多通道测试方法扩展对被测实现的控制和观察，通过扩充参考实现增强系统的测试能力。将这些理论，技术应用于系统中，对路由协议开展了有效的测试活动，为国产高性能路由器的开发提供了有力的支持，也进一步增强了PITS系统的功能和适用性。     

Strengthening of Preloaded RC Beams Using Hybrid Carbon Sheets

Reinforced concrete (RC) beams subject to service loads of 40 or 60% of steel yielding were strengthened using hybrid continuous carbon fiber sheets. The hybrid systems were made of high-strength and high-modulus carbon sheets, and compared with systems using only high-strength carbon. It was found that the use of high-modulus carbon sheets in hybrid systems could increase the yielding load, the flexural stiffness, the postyielding ductility, and reduce the crack opening in concrete. The slope changes on load-deflection curves at steel yielding are not noticeable in hybrid systems. The tensile strains developed in hybrid sheets after the fracture of high-modulus carbon are higher in magnitude and distributed in a larger area, leading to an ultimate carbon fracture with concrete crushing. These unique features are attributed to the high stiffness and low ultimate tensile strain of the high-modulus carbon fibers which stiffen the structures, avoid or delay the fiber-reinforced polymer debonding, and facilitate the deformability during their subsequent breakdown.     

大江河口三维非线性斜压水流盐度数学模型

本文建立了河口三维非线性斜压水流盐度数学模型。该模型通过。坐标变换，使整个水域垂直方向可采用相同的分层。基于过程分裂法，将三维流动分成表面重力波（外模式）和内重力波（肉模式）。外模式采用改进型双步全隐有限差分DSI法进行计算，内模式利用欧拉-拉格朗日公式，改进三维垂直方向隐式格式，减小了数值耗数，提高了计算精度及稳定性。该模型应用于长江口三维盐水入侵计算，结果表明水流盐度分布与实测一致。     

Hydrogen Reduction and Microstructural Changes of ISF Sinter

The reduction rate and microstructural changes of imperial smelting furnace (ISF) sinter have been investigated by means of thermogravimetric analysis, X-ray difFraction (XRD), scanning electron microscope (SEM ), energy dispersive analysis of X-ray (EDAX) and optical microscope.It is demonstrated that the overall reaction rate of the reduction is influenced by temperature and hydrogen partial pressure in H2 /N2 gas mixtures. There are two distinct zones observed in the partially reduced sinter. The reduction of zincite proceeds predominantly in a narrow range between the two zones, while the reduction of tead oxide and silicate takes place throughout the sinter. The differences between zincite and lead oxide or silicate in reducibility are analysed by thermodynamlcs. The phase transformations and microstructural changes occurring during the reduction process are discussed     

Analysis of the detectivity for triple-layer heterojunction GaSb/GaInAsSb infrared detectors

In this paper, the detectivity is calculated and analyzed with the front-or backside illuminated case for both N-GaSb/p₂-Ga_0.8In_0.2As_0.19Sb_0.81/p₁-Ga_0.9In_0.1As_0.09Sb_0.91 and N₁-GaSb/n₂-Ga_0.9In_0.1As_0.09Sb_0.91/p-Ga_0.8In_0.2As_0.19Sb_0.81 infrared photovoltaic detectors, respectively. The analysis results show that the main absorption appears in the p-type Ga_0.8In_0.2As_0.19Sb_0.81 material with either front- or backside illuminated case for above two structures. In each structure, the carrier concentration obviously affects the detectivity. The carrier concentration in the wide-bandgap material for the isotype heterojunction should be reduced as low as possible to reduce the tunneling rate at the isotype heterointerface. Moreover, the change of the detectivity with the p-side surface recombination velocity for the N₁-n₂-p structure is more sensitive than that with the p₁-side surface recombination velocity for the N-p₂-p₁ structure. In the N-p₂-p₁ structure with the incident light from the p₁-side surface, two-color detection is achieved.     

低渗透油藏生产井关井测压时间的计算与应用

低渗透油藏的生产井压裂后，在单井试油试采过程中，压力恢复测试关井时间不同，其中有些井压力恢复曲线不能出现边界反应段，渗流不能反映地层中真实流动特征。针对这种情况，基于长庆绥靖油田塞39井区长：低渗透油藏大量试井和实际生产资料，利用现代试井解释理论，研究合理关井时间的界限及其计算方法。结果表明，当油井关井测压时间达到3倍地层径向流开始出现的时间后，利用此时的压力数据解释地层参数和地层压力，其结果的误差小于5％，同时能较准确地判断边界类型。计算的理论曲线和霍纳法解释值非常接近，对于塞39井区，若预先知道某生产井地层有效渗透率值，可从理论曲线查出压力恢复试井的关井时间，否则，建议按照该井区地层有效渗透率（大约在6mD左右），将不稳定试井测试时间控制在25d以上为宜。图4表3参14     

我国煤炭生产的环境问题及其对策研究

论文分析了我国煤炭生产中所存在的环境问题 ,并提出采取应用全面绿色管理、贯彻实施ISO14 0 0 0系列标准及推广应用清洁生产等对应措施和方法。其中全面绿色管理是作者首次提出的全新概念。     

Transient aspects of inner wall temperatures at different spatial positions in fluidized bed evaporators

In this work, the instantaneous data of inner wall temperatures obtained at given axial positions but for different heated tubes or at various axial positions but at the same heated tube in a tube-bank fluidized bed evaporator with a vapor–liquid–solid external natural circulation flow were analyzed by employing linear and nonlinear time series analysis methods, including correlation dimension and Kolmogorov entropy analyses besides time domain, power spectrum and autocorrelation analyses. It is found that nonlinear characteristics of the wall temperature time series vary with spatial position in the evaporator at given operation conditions, and thus the multi-phase flow boiling behavior. However, the signals obtained at given axial position but different heated tubes in the evaporator exhibit more similar nonlinear evolution behavior, and those measured in the same heated tube but at different axial heights in the evaporator undergo more distinct nonlinear dynamic behavior. Multi-scale phenomena in different spatial positions are also found and discussed. These transient aspects of inner wall temperatures are closely related to the average holdup of solid particles and motion of vapor bubbles in vapor–liquid–solid flow. These results can provide some valuable information on the system modeling and controlling from the point of view of nonlinearity.