Application of evolutionary programming to transient andsubtransient parameter estimation

This paper presents an artificial intelligence approach of using evolutionary programming to estimate the transient and subtransient parameters of a generator under normal operation. The estimation using evolutionary programming is compared with that using a corrected extended Kalman filter. The comparisons with both simulation and micromachine test results show that evolutionary programming is robust to search the real values of parameters even when the data are highly contaminated by noise, while with the extended Kalman filter, the estimation tends to diverge with such data     

Effect of type of processing on the microstructural features and mechanical properties of Al-Cu/SiC metal matrix composites

In this study, an aluminum based metallic matrix (Al-2wt.% Cu) was reinforced with SiC particulates using a conventional casting technique and a new disintegrated melt deposition technique. Microstructural characterization studies conducted on the samples taken from disintegrated melt deposition technique revealed a more uniform distribution of SiC particulates and good interfacial integrity between SiC particulates and metallic matrix when compared to the conventionally cast composite samples. Results of ambient temperature mechanical tests demonstrate an increase in 0.2% YS and ultimate tensile strength of samples taken from disintegrated melt deposition technique when compared with the unreinforced and conventionally cast composite samples. The results of microstructural characterization and mechanical testing were finally rationalized in terms of the nature of processing technique employed to reinforce Al-2wt.% Cu metallic matrix with SiC particulates.     

Random switching techniques for inverter control

New techniques which dramatically reduce acoustic noise by randomising the inverter switching frequency for inverter control are presented. It is shown that the proposed techniques combine the advantages of conventional pulsewidth modulation (PWM) techniques based on regular-sampling techniques and random PWM techniques     

Tramadol, M1 metabolite and enantiomer affinities for cloned human opioid receptors expressed in transfected HN9.10 neuroblastoma cells

Tramadol hydrochloride is a centrally acting synthetic analgesic in widespread clinical use. Despite different degrees of opioid-like characteristics in preclinical tests, it is characterized by lack of full naloxone reversibility or naloxone-precipitated withdrawal in humans. To investigate this apparent discrepancy, the present study measured the affinity of tramadol (and its enantiomers) and an active O-desmethyl metabolite (M1) (and its enantiomers) to cloned human opioid receptors of the mu, delta and kappa type stably expressed in HN9.10 neuroblastoma cells. At mu sites, the Ki values for tramadol, its (+) and (-) enantiomers, M1, and its (+) and (-) enantiomers were 17000, 15700, 28800, 3190, 153 and 9680 nM, respectively, compared to 7.1 nM for morphine. These results are consistent with the suggestion of a non-opioid contribution to the clinical profile of tramadol.     

Ternary alloying study of MoSi2

Ternary alloying of MoSi₂ with adding a series of transition elements was investigated by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Iron, Co, Ni, Cr, V, Ti, and Nb were chosen as alloying elements according to the AB₂ structure map or the atomic size factor. The studied MoSi₂ base alloys were prepared by the arc melting process from high-purity metals. The EDS analysis showed that Fe, Co, and Ni have no solid solubility in as-cast MoSi₂, while Cr, V, Ti, and Nb exhibit limited solid solubilities, which were determined to be 1.4±0.7, 1.4±0.4, 0.4±0.1, and 0.8±0.1. Micro-structural characterization indicated that Mo-Si-M_VIII (M_VIII=Fe, Co, Ni) and Mo-Si-Cr alloys have a two-phase as-cast microstructure, i.e., MoSi₂ matrix and the second-phase FeSi₂, CoSi, NiSi₂, and CrSi₂, respectively. In as-cast Mo-Si-V, Mo-Si-Ti, and Mo-Si-Nb alloys, besides MoSi₂ and C40 phases, the third phases were observed, which have been identified to be (Mo, V)₅Si₃, TiSi₂, and (Mo, Nb)₅Si₃.     

凸轮机构基圆半径的确定方法及其分析

基圆半径的确定方法，除了用图解法和试算法外，还可用解析法和图解分析法求解。４种方法各有优缺点，设计时要根据具体情况选择。     

第三只眼看进品保健品

许多国家大多没有严格意义上的保健品概念，美国等国家将其统称为“功能食品”。我国应用“保健品”一词，旨在将其与药品和食品两大门类区分开来。美国的“保健品”发展速度和规模比较大，同时由于其先进的制造和科研技术，引领着世界功能食品的潮流。随着我国社会的发展，保健品的生产和研发也逐步赶上国际的步伐，而大量的进口保健品也已经进入寻常百姓家。