基于PC的机车车轮在线故障检测系统

机车车轮的在线故障检测对提高行车的安全性有重要的意义。文章采用先进的嵌入式工业PC机,开发了PC机与底层数据采集系统基于CAN总线的高效、可靠的数据通信协议,并在此基础上,根据采集到的机车轮运行过程中振动和温度数据,进行数据的可视化显示和机车车轮的故障诊断。试验证明该系统性能稳定,运行可靠,能满足机车运行过程中的车轮在线故障诊断的要求。     

Long-pulse N2UV lasers at 357.7, 380.5, and 405.9 nm in N2/Ar/Ne/He mixture

Using long-pulse electron-beam pumping, long-pulse laser emissions at 357.7, 380.5, and 405.9 nm have been observed in the second positive system of nitrogen with pulse durations of 150, 400, and 400 ns, respectively. Substantial improvements in laser performance were observed by adding excess Ne and He into N2+ Ar mixtures. Peak powers of 56, 44, and 66 kW/cm²have been obtained for the three wavelengths, respectively.     

空间-时间预RAKE系统

本文提出了一种适用于TDD/DS-CDMA下行链路的空间-时间预RAKE系统。该系统能实现空间的选择性发送和时间的预RAKE发送。然后给出了单用户和多用户情况下的该系统性能分析,并讨论不同信道参数(角度扩散,Doppler频率和突发帧长等)对系统性能的影响。     

Analytical models for call blocking and dropping in sectorized cellular networks with fractional frequency reuse

In this paper, we construct mathematical models to analyze the probabilities of new call blocking and handoff call (HC) dropping for a sectorized cellular network with fractional frequency reuse (FFR). Because a sectorized FFR network (SFN) consists of two areas, the super group (SG) and the regular group (or sectors), three different types of HCs may happen when a mobile station (MS) moves from the SG to a sector, from a sector to the SG, or from one sector to another sector. To characterize three types of HCs, we first derive the area transition probability, which is defined as the reciprocal of MS's average residence time in an area (i.e., sector or SG). Moreover, we construct the model of Markov chains and derive the state transition rates. Then on the basis of the stationary probabilities of Markovian states, we derive the three types of blocking probabilities of new calls and two types of dropping probabilities of HCs. Finally, we conduct extensive numerical simulations. From the results of numerical simulations, we reveal two important rules for choosing the optimal radius of the SG, with which the system blocking and dropping probability can be effectively minimized. Copyright © 2014 John Wiley & Sons, Ltd.     

Removal of gallium (III) ions from acidic aqueous solution by supercritical carbon dioxide extraction in the green separation process

Supercritical carbon dioxide extraction, which is a feasible "green" alternative, was applied in this study as a sample pretreatment step for the removal of gallium (III) ions from acidic aqueous solution. The effect of various process parameters, including various chelating agents, extraction pressure and temperature, dimensionless CO(2) volume, the concentration of the chelating agent, and the pH of the solution, governing the efficiency and throughput of the procedure were systematically investigated. The performance of the various chelating agents from different studies indicated that the extraction efficiency of supercritical CO(2) was in the order: thiopyridine (PySH)>thenoyltrifluoroacetone (TTAH)>acetylacetone (AcAcH). The optimal extraction pressure and temperature for the supercritical CO(2) extraction of gallium (III) with chelating agent PySH were found to be 70 degrees C and 3000psi, respectively. The optimum concentration of the chelating agent was found to be 50ppm. A value of 7.5 was selected as the optimum dimensionless CO(2) volume. The optimum pH of the solution for supercritical CO(2) extraction should fall in the range of 2.0-3.0.     

Low power and high speed multiplier design with row bypassing and parallel architecture

This paper presents a low power and high speed row bypassing multiplier. The primary power reductions are obtained by tuning off MOS components through multiplexers when the operands of multiplier are zero. Analysis of the conventional DSP applications shows that the average of zero input of operand in multiplier is 73.8 percent. Therefore, significant power consumption can be reduced by the proposed bypassing multiplier. The proposed multiplier adopts ripple-carry adder with fewer additional hardware components. In addition, the proposed bypassing architecture can enhance operating speed by the additional parallel architecture to shorten the delay time of the proposed multiplier. Both unsigned and signed operands of multiplier are developed. Post-layout simulations are performed with standard TSMC 0.18 μm CMOS technology and 1.8 V supply voltage by Cadence Spectre simulation tools. Simulation results show that the proposed design can reduce power consumption and operating speed compared to those of counterparts. For a 16×16 multiplier, the proposed design achieves 17 and 36 percent reduction in power consumption and delay, respectively, at the cost of 20 percent increase of chip area in comparison with those of conventional array multipliers. In addition, the proposed design achieves averages of 11 and 38 percent reduction in power consumption and delay with 46 percent less chip area in comparison with those counterparts for both unsigned and signed multipliers. The proposed design is suitable for low power and high speed arithmetic applications.     

Tunable Liquid Crystal-Resonant Grating Filter Fabricated by Nanoimprint Lithography

We demonstrate a tunable filter consisting of a subwavelength resonant grating filter cladded by a liquid crystal cell. The resonant wavelength of the grating filter is tuned by electrically varying the refractive index of the liquid crystal. A tuning range of around 20 nm has been achieved.     

Water permeation analysis on gas diffusion layers of proton exchange membrane fuel cells for Teflon-coating annotation

This study presents an analysis of water permeation of a polytetrafluoroethylene (PTFE)-coated gas diffusion layer (GDL) to determine the influence of hydrophobic treatment on the GDL for diagnosis of water flooding. It is found that the behaviour of water drainage is controlled by the pore configuration instead of the hydrophobicity in GDL. Better water drainage is achieved by the action of the Teflon coating in modulating the GDL pore configuration to give both a larger average pore size and a wider distribution of pore size. The results show that water penetration through the GDL must overcome a threshold surface tension defined by the largest pore range. A 30 wt.% PTFE coating of a GDL is shown to generate a satisfactory pore configuration, explaining the improved cell polarization performance with a lower driven pressure (∼1.91 kPa) and a higher rate of water drainage.     

力学量取值定理

绍了广义Ｃａｕｃｈｙ－Ｓｃｈｗａｒｚ不等式，测不准量子力学中的两项假设及力学量取值定理，并把我们的表述与形式上接近的一些理论作了比较．     

Large-Scale Economic Dispatch by Artificial Ant Colony Search Algorithms

This paper presents a new cooperative agent search approach for solving power economic dispatch problems. One of the main objectives of this paper is to investigate the applicability of an alternative agent search method in power system optimization. The proposed Artificial Ant Colony Search Algorithm (ACSA) is based on the results of real ant trail formation and foraging obtainedfrom theoretical biology science. A new encoding technique is proposed to overcome the difficulties of applying ACSA in a continuous search space, such as economic dispatch problems. An object-oriented ACSA system is developed and programmed. The effectiveness of the proposed technique has been demonstrated on a number of systems, which include an actual utility system of up to 40 units. Comparison with conventional genetic algorithms is presented. The outcome of the study shows that an emergent collective search ability resulted from the massive parallel fashion and positive feedback of ant colony is particularly attractive in addressing some difficult engineering problems; however, it should be observed that current research of Ant Colony Search Algorithm in power system is relatively new and still at a feasibility stage. More potentially beneficial work remains to be done.