基于ICE2PCS05高功率因数校正电路的设计

以单相Boost有源功率因数校正电路为研究对象,分析有源功率因数校正技术的基本原理及其分类,并对每一类型电路的拓扑结构、工作特点及工作方式进行比较。逆变焊机输入整流电路中的滤波电容是导致输入电流波形畸变的原因所在,产生高次谐波,并降低电源的功率因数。基于新型功率因数校正芯片ICE2PCS05,设计一款功率为300 W,输出为400 V的高功率因数校正电路,详细分析该电路的工作原理、升压电感、电容、功率开关管、二极管、开关频率和ICE2PCS05外围电路等部分参数的设计方式,并给出其测试结果。实验结果表明,该设计电路合理可行、输入电流畸变小,输出电压恒定,可获得高功率因数。     

Purification of S-PG05 using Simulated Moving Bed Chromatography

Abstract

S-PG05 ((15S)-15-methyl-prostaglandin F₂ α methyl ester) was separated from the epimer R-PG05 and other impurities using SMB, combined with batch chromatography. Based on this technical procedure, 94% pure S-PG05 was obtained. Different column configurations and separation conditions of SMB have been selected. A non-synchronous shift with a “partial extract withdrawal” strategy has been employed, resulting in the saving of desorbent and the increase of the purity of S-PG05.     

Geometric Orbital Transfer Using Averaging Techniques

In this article, we focus on the coplanar orbital transfer of a satellite between Keplerian orbits, with low propulsion. We compute and analyze averaged systems associated with the energy minimization problem with the full control or control oriented in a single direction, tangential-normal or radial-orthoradial. This allows to understand the properties of each control direction in the optimal control problems.      

串行E2PROM芯片CAT24WC03/05/09/17及其应用

本文介绍了基于Ｉ＾２Ｃ总线串行工作的ＣＡＴ２４ＷＣ０３／０５／０９／１７芯片的管脚说明及功能描述,最后给出ＣＡＴ２４ＷＣ０３／０５／０９／１７芯片与单片机ＡＴ８９Ｃ５１的接口电路及程序框图。     

High Efficiency Al-Free 980nm InGaAs/InGaAsP/InGaP Strained Quantum Well Lasers

High efficiency Al-free InGaAs/InGaAsP/InGaP lasers emitting at 980nm are fabricated by MOCVD. The lasers exhibit a high internal quantum efficiency of 95 % and a low internal loss of 1.8 cm-1. Low threshold current density of 190A/cm2 and high slope efficiency of 1.06W/A are obtained by lasers with 800μm cavitylength. A high characteristic temperature 210C is also obtained by replacing the GaAs barrier with high-bandgap InGaAsP barrier. The measured vertical and parallel divergence angle are 40° and 8°, respectively.     

运用粒子图像测速仪研究双层桨搅拌槽内流体流动

The flow fields in a dual Rushton impeller stirred tank with diameter of 0.48 m （T） were measured by using Particle Image Velocimetry （PIV）. Three different size impellers were used in the experiments with diameters of D = 0.33T, 0.40T and 0.50T, respectively. The multi-block and 360° ensemble-averaged approaches were used to measure the radial and axial angle-resolved velocity distributions. Three typical flow patterns, named, merging flow, parallel flow and diverging flow, were obtained by changing the clearance of the bottom impeller above the tank base （C1） and the spacing between the two impellers （C2）. The results show that while C1 is equal to D, the parallel flow occurs as C2≥0.40T, C2≥0.38T and C2≥0.32T and the merging flow occurs as C2≤0.38T, C2≤0.36T and C2≤0.27T for the impellers with diameter of D=0.33T, 0.40T and 0.50T, respectively. When C2 is equal to D, the diverging flow occurs in the value of C1≤0.15T for all three impellers. The flow numbers of these impellers were calculated for the parallel flow. Trailing vortices generated by the lower impeller for the diverging flow were shown by the 10° angle-resolved velocity measurements. The peak value of turbulence kinetic energy （ k/V^2tip = 0.12-0.15 or above） appears along the center of the impeller discharging stream.     

天然气基乙炔工艺 分析与改进

This article presents an acetylene production process by partial oxidation/combustion of natural gas. The thermodynamic performance and exergy analysis in the process are investigated using the flow-sheeting program Aspen Plus. The results indicate that the most important destruction of exergy is found to occur in the reactor and water quenching scrubber, amounting to 8.23% and 10.39%, respectively, of the entire system. Based on the results of thermodynamic and exergy analysis, the acetylene reactor has been retrofitted. The improvement ratios of molar 02 to CH4 and molar CO to CN4 are 0.65 and 0.20, respectively. An improvement of the acetylene production system is proposed. Adopting the improvement operation conditions and using oil to realize the reaction heat recovery, the feedstock of natural gas is reduced by 9.88% and the exergy loss in the retrofitting process is decreased by 19.71% compared to the original process.     

锂离子电池正极材料LiNi_(0.5)Co_(0.5)O_2制备与电化学性能

采用球磨湿混和旋转合成相结合的新工艺制备了锂离子电池正极材料 L i Ni0 .5Co0 .5O2 ,并对材料进行了粒度、化学成分以及电化学性能测试。球磨湿混工艺能将原料混合均匀 ,并能有效地使粒度细化。旋转合成工艺能使混合料在均匀的温度场中进行反应 ,并使反应产物粒度均匀和成分均匀。制备的 L i Ni0 .5Co0 .5O2 为单一的 α- Na Fe O2 层状结构 ,粉末粒度分布范围窄 ,平均粒径约为 8μm～ 10μm。电化学性能测试结果表明 ,在 0 .2 m A/cm2 充放电流密度和 3 .0 V～ 4 .2 V电压范围内 ,首次充电容量为 173 m Ah/g,放电容量为 14 8m Ah/g。循环次数达 3 0次时 ,放电容量还有 12 9m Ah/g,循环稳定性良好。球磨湿混和旋转合成相结合的固相合成新工艺能制备出电化学性能良好的L i Ni0 .5Co0 .5O2 正极材料。     

Resolucion por programacion parametrica del problema Multiobjetivo Lineal Difuso

Resumen En este artículo se propone una solución difusa al problema Multiobjetivo Lineal Difuso. Tal solución contiene, como valores particulares, las soluciones puntuales que otros autores han obtenido. El método que se emplea es independiente de la linealidad de las funciones de pertenencia que se consideren. El problema también se extiende al caso en que el conjunto de restricciones sea, junto con los objetivos, difuso.

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In this paper a fuzzy solution to the Fuzzy Linear Vectormaximum problem is proposed. This solution involves the puntual solutions obtained by other authors, as particular values. Method used and linearity of membership functions considered are independent. For the case in which both objective and constraints are fuzzy the problem is extended too.

     

Simultaneous approximation by (0,..., R−2, R) interpolators

The present note describes a general technique to derive quantitative assertions concerning the degree of simultaneous approximation by lacunary interpolation operators of the (0, ..., R−2, R) type. The effectiveness of our technique is demonstrated by improving various classical theorems, and by showing how other significant statements can be obtained in quite a natural fashion, too. Dedicated to the late Arun Kumar VARMA