双星载旋转机构非确定等价鲁棒自适应控制

针对航天器携带的两副旋转机构同时姿态机动的精确控制问题提出一种鲁棒自适应控制方法.从关联系统的角度建立系统动力学模型,有效精确描述系统内各刚体动力学耦合项与非耦合项.采用“航天器本体姿态稳定、同时各旋转机构姿态机动”的复合控制策略:考虑到航天器本体转动惯量参数无法精确获得,应用非确定等价自适应控制方法设计姿态稳定控制器,在确保姿态全局渐近稳定的同时有效令不确定参数估计值精确逼近真实值或进入特定集合;考虑到各旋转机构姿态机动时受到航天器本体动力学耦合的影响,设计了鲁棒H∞姿态机动控制器以抑制动力学耦合的作用.仿真结果验证了所提出方法的有效性.     

Cupriavidus necator JMP134细菌人工染色体基因组文库的构建与鉴定

Cupriavidus necator JMP134(C.necator JMP134)可以降解60多种芳香族化合物,在环境污染治理方面具有良好的应用前景.该菌株基因组含有两个苯酚降解基因簇,克隆并研究其功能具有重要的理论和应用价值.以pIndigo-BAC 5为载体,构建了C.necator JMP134的细菌人工染...     

Plasma Electrolysis for Titanium Modification Technique

In the present work, the wear behaviour of coatings produced on Ti -6Al -4V alloy by plasma electrolysis oxidation method was studied. The wear resistances of the coatings with different thickness were contrasted. The wear tests were performed using a pin -on -disc wear machine under dry sliding conditions. The coated samples demonstrated wear rates up to 5-12 times lower than that of the uncoated substrates tested.     

生物活性炭对焦化废水中萘的吸附降解

以荼为唯一碳源,驯化分离出高效荼降解菌NPA-5,将NPA-5负载于活性炭上,制备出生物活性炭.研究生物活性炭对荼的吸附特征、生物吸附动力学及其对焦化废水中荼的吸附降解机制.结果表明,活性炭对荼的等温吸附符合Langmuir和Freundlich等温吸附模型；负载NPA-5的生物活性炭能较快地降解废水中的荼,降解率达99.3％；生物活性炭对荼的降解符合一级动力学模型.     

西方发达国家廉租房法律制度及其借鉴

西方发达国家有着比较完善的住房社会保障体系，廉租房法律制度是其重要组成部分。这些国家从保障公民的居住权出发。非常注重廉租房法律制度的建设，较好地解决了公民的居住权问题。发达国家的经验对于我国目前的廉租房法律制度的建设具有非常重要的借鉴作用。     

浅析SNMPv3的安全性

介绍了SNMP在安全方面对各版本所做的改进，重点阐述了SNMPv3的安全机制。分析了SNMPv3的安全性。     

IGBT 模块故障机理及其预报方法综述

以IGBT模块的内部结构和材料特性为基础,研究了焊料层疲劳、铝键接线断裂或剥离、DCB基片失效等封装级故障产生机理;分析栅氧化层击穿、电过应力、辐射失效等器件级故障的产生机理;最后,分别给出了两大类故障的预报方法。     

臭氧-固定化生物活性炭去除煤气废水中酚的研究

将降解酚类化合物的高效工程菌固定在活性炭上,采用臭氧-固定化生物活性炭(O3-IBAC)工艺处理煤气废水。研究证明:在臭氧投量为18mg/L ,接触时间为2 0min时,臭氧可以改变水中有机物的结构,但是有机物的总量没有明显的变化。当煤气废水进水COD、酚类的质量浓度分别为5 0 0mg/L、95mg/L左右时,采用O3-IBAC工艺对两者的去除率可以分别达到80 %、92 %以上。系统运行6个月后,IBAC上工程菌分布均匀,炭数量可达6 .1×10 3cfu/g ,而且工程菌在种类上仍然占优势。同时,运用生态位理论解释了工程菌可以长期稳定存在,且保持较高的生物活性的原因     

基于UGNX4.0的连杆机构运动学仿真

介绍了软件UG NX4.0的机构仿真功能,在此基础上对连杆机构的仿真过程作了较详细的陈述,给出其位移、速度和加速度曲线,为利用UG实现机构的CAD/CAE一体化作出有益的探索。     

Histone chaperones: 30 years from isolation to elucidation of the mechanisms of nucleosome assembly and disassembly

Some three decades have passed since the discovery of nucleosomes in 1974 and the first isolation of a histone chaperone in 1978. While various types of histone chaperones have been isolated and functionally analyzed, the elementary processes of nucleosome assembly and disassembly have been less well characterized. Recently, the tertiary structure of a hetero-trimeric complex composed of the histone chaperone CIA/ASF1 and the histone H3-H4 dimer was determined, and this complex was proposed to be an intermediate in nucleosome assembly and disassembly reactions. In addition, CIA alone was biochemically shown to dissociate the histone (H3-H4)₂ tetramer into two histone H3-H4 dimers. This activity suggested that CIA regulates the semi-conservative replication of nucleosomes. Here, we provide an overview of prominent histone chaperones with the goal of elucidating the mechanisms that preserve and modify epigenetic information. We also discuss the reactions involved in nucleosome assembly and disassembly. Received 5 July 2007; received after revision 8 September 2007; accepted 13 September 2007 M. Eitoku, L. Satoa: These authors contributed equally to this work.