激光晶体Nd:YVO4的形貌及生长缺陷

本文报道了应用环境扫描电镜（ESEM）和同步辐射X射线白光形貌术对采用提拉法生长出的Nd:YVO4晶体进行的形貌及生长缺陷的分析,获得了该晶体的开裂表面的ESEM形貌像以及取自晶体肩部和中间部位的（001）面的同步辐射白光形貌像,观察到了位错、包裹物等缺陷,可为生长高质量的Nd:YVO4晶体提供重要的启示.     

A Compositional Framework for Hardware/Software Co-Design

We describe a compositional framework, together with its supporting toolset, for hardware/software co-design. Our framework is an integration of a formal approach within a traditional design flow. The formal approach is based on Interval Temporal Logic and its executable subset, Tempura. Refinement is the key element in our framework because it will derivefrom a single formal specification of the system the software and hardware parts of the implementation, while preserving all properties of the system specification. During refinement simulation is used to choose the appropriate refinement rules, which are applied automatically in the HOL system. The framework is illustrated with two case studies. The work presented is part of a UK collaborative research project between the Software Technology Research Laboratory at the De Montfort University and the Oxford University Computing Laboratory.     

Integration of solvent extraction and liquid membrane separation: An efficient tool for recovery of bio-active substances from botanicals

An integrated process based on simultaneous solid-liquid extraction and liquid membrane separation is proposed for recovery and isolation of valuable species from botanicals. This integration provides complete exhausting of the solid material even in the case of very low solubility of the specified solute in the extracting solvent. Selectivity of the liquid membrane ensures a preferential transport of the desired solute from the native extract into the strip solution, while the other co-extracted species remain predominantly in the native extract.     

美国C.F布朗公司大型合成氨装置用材简介

介绍了美国Ｃ．Ｆ布朗公司大型合成氨装置根据操作条件和介质腐蚀程度不同，如何选择管道和设备材料，并对其用材进行逐一剖析。     

The block to HIV-1 envelope glycoprotein-mediated membrane fusion in animal cells expressing human CD4 can be overcome by a human cell component(s)

Membrane fusion mediated by interaction of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein with the human CD4 molecule generally requires that the CD4 be expressed on a human cell. The failure of murine or simian cells expressing human CD4 to form syncytia upon mixing with cells expressing envelope glycoprotein could not be corrected by expression of both molecules at extremely high surface levels using vaccinia virus expression vectors. Video fluorescence microscopic analysis of fluorescent dye transfer between fusing cells indicated that the block occurred at the level of membrane fusion between individual pairs of cells. To gain insight into the basis for this fusion block, we tested the ability of fluorescent probe cells expressing envelope glycoprotein to fuse with transient animal x human hybrid giant cells expressing human CD4. The hybrid giant cells were generated either by low-pH-induced fusion of vaccinia-infected cells or by CD4/HIV-1 envelope glycoprotein-mediated cell fusion. We observed that envelope glycoprotein-expressing probe cells efficiently fused with CD4-expressing animal x human hybrid giant cells, independent of whether the CD4 was originally expressed on the animal or on the human cell. Fusion did not occur with CD4-expressing giant cells derived from animal cells alone. These results indicate that the fusion block is not due to dominant inhibitory components in the animal cell. Rather, they suggest that human cells contain an additional component(s) which, when transferred to the CD4-bearing animal cell, confers the ability to undergo membrane fusion mediated by the HIV-1 envelope glycoprotein.     

Surface Hardening of Alloy Steels Using a High Intensity Electron Beam

Energy sources such as electron or laser beams have been extensively used for materials processing. Surface hardening is an established process used in industry. A combination of nitriding and electron beam treatment is used to modify alloy steel with nominal composition (wt.%) of 0.42% C, 0.96% Cr, 0.6% Mn, 0.37% Si, balance Fe. The hardness of the hardened layer varies in the range 800-850 HV. The high hardness is due to a refined microstructure consisting of a -solid solution (nitrous martensite) and γ - solid solution (nitrous austenite) and dispersed fine nitride precipitates. The wear resistance the of electron beam treated layer is double that of the ion nitrided specimens.     

预应力混凝土连续箱梁桥抗侧翻设计关键参数

为研究预应力混凝土连续箱梁桥在超载作用下的抗侧翻设计的关键参数,以某连续箱梁桥为背景,采用ＭＩＤＡＳ／Ｃｉｖｉｌ建立三种有限元模型（考虑支座布设方式的变化）,研究在３倍超载作用下的连续箱梁的抗倾覆能力变化规律。分析结果表明:独柱墩模型的最小支座反力要远小于另外两种模型;随着支座间距的增大,箱梁的横向抗倾覆系数增大,改变支座间距或改变支撑类型可以有效的改善支座的受力情况;小间距双支座模型和独柱墩模型的抗倾覆能力和抗弯能力不匹配,不能发挥梁的抗弯能力,而大间距双支座模型的倾覆超载系数和强度超载系数较为接近;大间距双支座的支座布设方式在偏心超载作用下的抗倾覆能力较强。     

固氮作物紫云英苜蓿叶象甲药剂筛选试验初探

为有效防治危害紫云英的苜蓿叶象甲,笔者测定了5种杀虫剂对叶象甲的田间防治效果。结果表明,每667 m²喷施10%联苯菊酯乳油30 mL防治苜蓿叶象甲幼虫,速效性和持效性优异,药后7 d和14 d的平均防效分别为92.2%和98.2%;喷施60 g/L乙基多杀菌素悬浮剂30 mL和4.5%高效氯氰菊酯乳油30 mL的防效次之,药后14 d平均防效分别为86.5%和69.8%;喷施10%虫螨腈悬浮剂50 mL防治苜蓿叶象甲速效性好,药后7 d平均防效为62.4%;喷施5.7%甲维盐水分散粒剂10 g持效性好,药后14 d平均防效为83.4%。     

Synthesis and self-association in aqueous media of poly(ethylene oxide)/poly(ethyl glycidyl carbamate) amphiphilic block copolymers

New temperature sensitive AB, ABA, and BAB amphiphilic block copolymers consisting of hydrophilic poly(ethylene oxide) and hydrophobic poly(ethyl glycidyl carbamate) blocks were synthesized by anionic polymerization followed by chemical modification reactions. The self-association of the block copolymers in aqueous media was studied by UV-vis spectroscopy and dynamic and static light scattering. The obtained block copolymers spontaneously form micelles in aqueous media. The critical micellization concentration varied from 0.5 to 4 g/L depending on the copolymer architecture and composition. The influence of the temperature upon the self-association of the block copolymers was investigated. The increase of temperature did not affect the value of the critical micellization concentration, but led to the formation of better defined micelles with narrow size distribution.