单端孢霉烯族毒素及其脱毒微生物国外研究进展

单端孢霉烯族毒素是一大类霉菌毒素,对人与动物具有非常大的毒性。它们广泛存在于粮食、饲料及以被污染粮食为原料的食品中,不仅给食品安全带来了一定的隐患,也影响到畜牧业生产。许多学者正在研究食品和饲料中单端孢霉烯族毒素的控制方法,其中生物脱毒是目前的研究热点,例如利用微生物将毒素转化成无毒或低毒的化合物。由于生物脱毒具有许多优点,因而具有广阔的前景。本文综述了单端孢霉烯族毒素的结构与毒性官能团,以及单端孢霉烯族毒素脱毒微生物方面的研究进展,旨在为单端孢霉烯族毒素的转化降解研究提供参考。     

基于PLC及变频器的煤矿载货电梯电器控制改造

采用可编程逻辑控制器(PLC)控制变频器对继电器控制的五层五站载货电梯控制系统进行改造,改造后的载货电梯在运行性能、安全性能、节能等方面均优于原电梯。     

响应面法优化猪脾免疫活性多肽提取工艺研究

目的通过响应面法,优化猪脾中免疫活性多肽的提取工艺。方法选择适当的酶水解猪脾脏,并在单因素试验的基础上,采用Box—Behnken设计优化提取工艺,建立各因素与提取液中多肽含量的数学模型,最后采用淋巴细胞转化试验初步验证其活性。结果获得了猪脾中免疫活性多肽提取工艺：料液比1：2．6g／mL,温度40℃,pH7．0,胰蛋白酶浓度485U／g,中性蛋白酶浓度1711U／g,每100g含活性多肽2．930g,与理论计算值2．929g基本一致,活性约为对照组的1．5倍。结论确定了猪脾免疫活性多肽最佳提取工艺。     

Role of ComEA in DNA uptake during transformation of competent Bacillus subtilis

The role of the competence protein ComEA in DNA uptake during transformation of competent Bacillus subtilis was analyzed by lysed-protoplast transformation (LP transformation). A comEA deletion mutant was constructed by a fusion polymerase chain reaction. Transformants of the mutant were obtained by LP transformation at a frequency of 1.1 × 10(2) transformants per μg DNA, representing a low relative efficiency of transformation [RET (mutant/wild type)] of 2.7 × 10(-6). This implied an important role of the protein during DNA uptake. When analyzing LP transformation of comEA with a plasmid (5.7 kb), a similar RET (mutant/wild type) of 5.6 × 10(-5) was obtained. Following addition of DNA into the comEA mutant culture, the number of transformants increased at a rate of 0.5 transformants/min, which was very low compared with the wild-type (6.9×10(4) transformants/min). However, even in the comEA mutant, DNA uptake began immediately after addition of DNA. Using co-transformation analysis of the comEA mutant, short linkages at distances of 2-156 kb could be detected, but not long linkages at distances of 671-1662 kb. Taken together, the results indicate that ComEA plays an important role in the transfer of transforming DNA into the DNA channel and in controlling the rate of DNA uptake.     

广东纺织服装产业创意增值的探讨

纺织服装产业的发展趋势是向现代时尚转变.广东纺织服装应由成本导向转变为价值导向,实现服装制造转型升级,本文探索了广东纺织服装产业创意增值的途径和方法,提出有关的观点.     

基于HYDSIM的电控气缸注油器设计与仿真

电控喷油是现代柴油机气缸润滑系统的研究趋势,对于机械式注油器的改造也是旧船改造的一个重要方向.为了提高性能和减少燃油消耗率,设计了一种回流阀脉冲式电控气缸注油器,并通过HYDSIM软件的模拟验证,说明该注油器创新设计的可行性.     

铝含量对钢渗碳动力学和贝氏体相变动力学的影响

采用井式渗碳炉和Gleeble3500型热模拟试验机测试了4种不同铝含量贝氏体钢的渗碳动力学和贝氏体相变动力学,研究了铝含量对其渗碳及贝氏体相变动力学的影响。结果表明:该钢的渗碳动力学方程为ξ=e(11.3-Q/RT)τ0.5,改变钢中铝含量对钢的渗碳动力学没有明显影响;随钢中铝含量增加,其贝氏体相变驱动力增大,使贝氏体转变加快,CCT曲线向左上方移动。     

(1+1)维KdV型方程的变速孤波解

利用齐次平衡原则,导出了一(1 1)维KdV型方程的Baecklund变换,借助于该变换．获得了该方程的孤波解：且由孤波解的形式可以看出,变系数影响孤波的振幅及波速。     

Analysis and optimization of low-pressure drop static mixers

Various designs of the so called Low-Pressure Drop (LPD) static mixer are analyzed for their mixing performance using the mapping method. The two types of LPD designs, the RR and RL type, show essentially different mixing patterns. The RL design provides globally chaotic mixing, whereas the RR design always yields unmixed regions separated by KAM boundaries from mixed regions. The crossing angle between the elliptical plates of the LPD is the key design parameter to decide the performance of various designs. Four different crossing angles from 90° to 160° are used for both the RR and RL designs. Mixing performance is computed as a function of the energy to mix, reflected in overall pressure drop for all designs. Optimization using the flux-weighted intensity of segregation versus pressure drop proves the existence of the best mixer with an optimized crossing angle. The optimized angle proves to be indeed the LLPD design used in practice: the RL-120 with θ = 120°, although RL-140 θ = 140° performs as good. Shear thinning shows minor effects on the mixing profiles, and the main optimization conclusions remain unaltered. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

促使我国陆军武器装备发展转型的主要动因分析

随着新时期军事变革的深入发展，我国陆军武器装备也进入了关键转型阶段，认清促使我国陆军武器装备发展转型的动因，对明确我陆军武器装备转型的方向，理清发展思路，具有现实和历史意义。