一种新型ICA算法在RFID系统中的应用

针对无线射频识别系统在通信过程中的防碰撞问题,从信号处理的角度,提出一种基于盲源信号并行分离技术的防碰撞处理算法,其中包括信号白化技术,以及一种改进的独立元分析(ICA)信号并行分离方法.功能仿真结果证明,该算法的吞吐率最高达到69％,与吞吐率只有18％的传统Aloha算法相比,该算法能提高防碰撞能力.     

声纹识别系统设计

论述了声纹识别的相关概念、应用领域及其区别于其他身份认证的优势,从软件方面构建了一个基于Matlab的声纹识别系统,并对整个系统进行了仿真实验,实验结果表明该系统具有较高的识别率,可应用于有限人群的身份认证。     

Light composite elliptic springs for vehicle suspension

For composites to compete in vehicle suspension applications, it is essential to control their failure by utilising their strength in principal direction instead of shear. This can be achieved efficiently by employing a new configuration instead of existing one. This study marries between an elliptical configuration and the woven roving composites.

In this paper, the influence of ellipticity ratio on performance of woven roving wrapped composite elliptical springs has been investigated both experimentally and numerically. A series of experiments was conducted for composite elliptical springs with ellipticity ratios (a/b) ranging from one to two. Typical failure histories of their failure mechanism are presented and discussed. In general, this study demonstrated that composites elliptical spring can be used for light and heavy trucks and meet the requirements, together with substantial weight saving. The results showed that the ellipticity ratio significantly influenced the spring rate and failure loads. Composite elliptic spring with ellipticity ratios of a/b 2.0 displayed the highest spring rate.     

Cooling rate effects on the microstructure and phase formation in Zr51Cu20.7Ni12Al16.3 bulk metallic glass

A detailed transmission electron microscope (TEM) study has been conducted to investigate the microstructures of the Zr₅₁Cu_20.7Ni₁₂Al_16.3 metallic glass formed at different cooling rates. It has been found that the most competitive crystalline phase to the amorphous structure is an oxygen-stabilized FCC NiZr₂-type phase, which in turn acts as the leading phase to trigger the formation of other crystalline phases in the slow-cooled alloy.     

Numerical evaluation of the effects of friction and geometric nonlinearities on the energy release rate in three- and four-point bend end-notched flexure tests

Nonlinear finite element analyses are used to examine the effects of friction and geometric nonlinearities on the energy release rate in three- and four-point bend end-notched flexure tests. Energy release rates are first determined by a recently developed direct energy balance approach. It is shown that the finite diameter loading rollers that are typically used in practical test set-ups cause both tests to be inherently nonlinear. The effect of these nonlinearities on the energy release rate is shown to be larger in the four point than the three point test and to increase with increasing roller diameter, increasing coefficient of friction along the crack plane, and decreasing supporting span length. For the four point test, the effect of these nonlinearities is also shown to increase with increasing ratio of inner to outer span length. Next, energy release rates at the onset of crack advance are determined by a simulated compliance calibration technique. This “perceived toughness” is compared with predictions of the “true toughness” given by the direct energy balance approach at the same load. It is shown that perceived toughnesses from this simulated compliance calibration procedure are larger than previously reported results that were obtained in a similar fashion using linear theory. In addition, the perceived toughness is shown to strongly depend upon the range used for fitting the load versus deflection data to obtain compliance. These findings are used to make some general recommendations regarding use of the two test methods and their associated data reduction techniques.     

西方发达国家环境税制的立法及对我国的启示

环境税已成为西方发达国家环境保护的一种重要的经济手段,通过介绍有代表性的丹麦、荷兰和美国等西方发达国家环境税制的立法状况,从立法指导思想、立法原则和立法内容上得出了构建我国环境税制的几点启示.     

Strain rate sensitivity of tensile properties in high Nb containing TiAl alloys

The effect of strain rate on the yield strength of high Nb containing TiAl alloy was studied. The results show that the strain rate sensitivity varies with the test temperature, and the yield strength is not sensitive to the strain rate at room temperature but significantly sensitive to the strain rate at high temperature. An increase of the strain rate or a decrease of the temperature results in an obvious change of fracture mode. It is found that the strain rate sensitivity of this alloy varying with temperature is due to the dislocation climb generated at high temperature.     

贵冶VPSA制氧机作业率攻关与改造

阐述了江铜贵溪冶炼厂二期工程引进的一套3800m3/h真空变压吸附制氧机(简称VPSA)的基本原理、工艺特点,分析了实际运行过程中周期短、作业率低的主要原因,采取了相应的技术改造和维护措施。     

Increased Vulnerability to Stress Following Opiate Exposures: Behavioral and Autonomic Correlates.

The authors used rats to study the impact of a history of opiate exposures on behavioral and autonomic responses to restraint stress. Brief restraint (30 min) provoked tachycardia and a pressor response, anxiety (as indexed by social interaction), grooming, and reduced exploration. The pressor response was reduced at 1 day, but not 7 days, after last opiate exposure; tachycardia was unaffected (Experiment 1). Stress-induced anxiety was potentiated 1 and 7 days after last opiate exposure (Experiment 2), and this potentiation was a function of dose (Experiment 3) and duration (Experiment 4) of opiate exposure. The results show that a history of opiate exposures alters vulnerability to stress and has implications for understanding coping, anxiety, and emotionality in former opiate users. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

大断面结构参数计算机模拟研究

为了解决弓长岭井下在矿体倾角较大、下盘围岩不稳固的情况下矿石回收率低的问题,本文从弓长岭铁矿的实际应用出发,深入研究了放矿口对散体移动规律的影响,在分析模拟系统的设计要求及功能的基础上,对D.Jolley模型进行建模.采用C#开发了计算机模拟系统,模拟实现了大断面出矿的一系列过程。该系统能够对多种方案进行模拟,并对模拟结果进行选优。仿真结果表明大断面进路出矿对提高矿石回收率的正确性及有效性。