芳香族和杂环化合物的CNDO/2计算硝基化合物辐射敏化效应的分子轨道研究

三十多种硝基芳香族和硝基杂环化合物的分子轨道能量已用CNDO/2进行了计算。在算得的最低空轨道能量和用脉冲辐解测得的单电子还原电位之间呈现较好的线性关系。对硝基咪唑类化合物,在最低轨道能量和敏化剂浓度C_(1.6)之间也得到了较好的线性关系。计算结果指出,亲电子敏化剂的特点是与靶分子相比,它们的最高占有轨道能量和最低轨道能量都比靶分子的低。     

BLOSSOMS： Building Lightweight Optimized Sensor Systems on aMassive Scale

As a joint effort between the Chinese Academy of Sciences and the Hong Kong University of Science and Technology, the BLOSSOMS sensor network project aims to identify research issues at all levels from practical applications down to the design of sensor nodes. In this project, a heterogeneous sensor array including different types of application-dependent sensors as well as monitoring sensors and intruding sensors are being developed. Application-dependent power-aware communication protocols are also being studied for communications among sensor nodes. An ontology-based middleware is built to relieve the burden of application developers from collecting, classifying and processing messy sensing contexts. This project is also developing a set of tools allowing researchers to model, simulate/emulate, analyze, and monitor various functions of sensor networks.     

浅谈虚拟仪器技术在钢铁工业中的应用

要虚拟仪器就是具有测控功能的计算机软件。虚拟仪器技术是现代计算机技术发展到一定程度的产物。文中介绍了虚拟仪器的概念、特点、硬件构成及软件特征,并结合实例介绍了基于LabVIEW的虚拟仪器设计方法和效果。展望了虚拟仪器的发展前景。     

Chemoenzymatic synthesis of HIV-1 gp41 glycopeptides: effects of glycosylation on the anti-HIV activity and alpha-helix bundle-forming ability of peptide C34

C34 is a 34-mer peptide derived from the C-terminal ectodomain of HIV-1 envelope glycoprotein, gp41. The C34 region in native gp41 carries a conserved N-glycan at Asn637 and the sequence is directly involved in the virus-host membrane fusion, an essential step for HIV-1 infection. This paper describes the synthesis of glycoforms of C34 which carry a monosaccharide, a disaccharide, and a native oligosaccharide moiety. The synthesis of the glycopeptide which carries a native high-mannose type N-glycan was achieved by a chemoenzymatic approach by using an endoglycosidase-catalyzed oligosaccharide transfer as the key step. The effects of glycosylation on the inhibitory activity and the helix-bundle forming ability of C34 were investigated. It was found that glycosylation moderately decreases the anti-HIV activity of C34 and, in comparison with C34, glyco-C34 forms less compact six-helix bundles with the corresponding N-terminal peptide, N36. This study suggests that conserved glycosylation modulates the anti-HIV activity and conformations of the gp41 C-peptide, C34.     

Selective quantification of trace palladium in road dusts and roadside soils by displacement solid-phase extraction online coupled with electrothermal atomic absorption spectrometry

There is a growing concern about the effect of palladium on human health because of the toxicity and increasing occurrence of palladium as a result of its extensive use in automotive catalytic converters. Development of reliable analytical methodologies for the determination of palladium in environmental materials is of great importance for critical evaluation of the possible risks for human health. In this work, a displacement solid-phase extraction technique was developed and online coupled to electrothermal atomic absorption spectrometry (ETAAS) for selective and sensitive determination of trace palladium in environmental samples without need of any special selective complexing agents, selective sorbents, and masking agents. The developed methodology involved the online formation of copper pyrrolidine dithiocarbamate (Cu-PDC), and the resultant Cu-PDC was extracted onto a microcolumn packed with the sorbent from a cigarette filter. Trace Pd(II) was selectively preconcentrated through loading the sample solution onto the microcolumn by online displacement reaction between Pd(II) and the extracted Cu-PDC on the microcolumn. The retained analyte was subsequently eluted with 40 microL of ethanol for online ETAAS determination. Interferences from coexisting heavy metal ions with lower stability of their PDC complexes relative to Cu-PDC were minimized. The tolerable concentrations of Cd-(II), Fe(III), Co(II), Mn(II), Cr(III), and Zn(II) were up to 2, 6, 40, 2, 1.5, and at least 100 mg L(-1), respectively. Compared with conventional solid-phase extraction methodology, the developed displacement solid-phase extraction protocol gave 2-4 orders of magnitude improvement in the maximum tolerable concentrations of coexisting heavy metal ions. With the consumption of only 2.8 mL of sample solution, an enhancement factor of 52 and a detection limit (3sigma) of 18 ng L(-1) were achieved at a sample throughput of 30 samples h(-1). The precision (RSD, n = 13) was 2.5% at the 1 microg L(-1) level. The present methodology was successfully applied to selective determination of trace palladium in local road dusts and roadside soils.     

离子注入20钢表面层的性能及结构

在1.0×10~(17)至7.0×10~(17)ions/cm~2范围内等间隔选取七个注入剂量,用75keV氮离子疰入20钢,形成表面强化层。用TRIM算法计算了注入后的氮离子浓度分布及损伤分布,测试了注入前后材料表面硬度和摩擦性能的变化。X衍射结果表明,注入层出现γ′-Fe_2N和ε-Fe_3N-Fe_2N新相。辐射损伤、第二相。间隙固溶体等是引起表面强化的主要原因。     

柠檬草精油对副溶血性弧菌的抑菌活性及机制

目的:探究柠檬草精油(LG-EO)对副溶血性弧菌的抑菌活性和机理。方法:通过测定LG-EO对副溶血性弧菌的最低抑制浓度(MIC)、时间-杀灭分析、上清液中AKP活性、电导率和蛋白质泄漏量、细胞形态、膜电位、呼吸链脱氢酶活力及胞内DNA的含量和结构等,研究LG-EO对副溶血性弧菌的抑菌活性和机制。结果:LG-EO对副溶血性弧菌的MIC范围80~120 μg/mL,在80~280 μg/mL处理浓度范围,其杀灭效果随浓度和时间的增加而提高,240 μg/mL LG-EO处理10 min即可灭活全部副溶血弧菌。与高于MIC的LG-EO共培养,副溶血弧菌细胞壁、膜的完整性被破坏,导致上清液中AKP活性、蛋白质含量和电导率上升,细胞边界模糊和内容物流失。菌体细胞膜电位、呼吸链脱氢酶和ATP酶活性等显著降低。基因组DNA的核酸电泳和紫外吸收光谱提示,DNA在LG-EO作用下流失严重并与主要成分柠檬醛发生互作。结论:柠檬草精油对副溶血性弧菌有较强的抑菌作用,LG-EO通过破坏细胞壁、膜构造,干扰细胞能量代谢,造成DNA流失或变性等快速杀灭副溶血性弧菌。本研究为探明LG-EO的抑制致病性弧菌机理奠定良好的基础,在水产品加工业中具有广泛的应用潜力。     

高弹性低硬度胶辊实施重加压的效果分析

探讨高弹性低硬度胶辊实施重加压的途径。从牵伸理论出发,分析论述了目前握持力与牵伸力在匹配方面存在的问题及影响高弹性低硬度胶辊实施重加压的"瓶颈"问题。对WRC-565型胶辊实施重加压进行了纺纱对比试验分析。指出:WRC-565型及其改进型表面不(微)处理铝衬胶辊能够适应重加压工艺,在前胶辊双锭加压为175 N的条件下,能够保持长时间正常工作,成纱条干水平有较明显的改善,较好地解决了高弹性低硬度胶辊实施重加压的"瓶颈"问题。     

细号纯棉色织物无PVA上浆实践

研究改性淀粉浆料AS-1在细号纯棉色织物上的应用效果.分析了AS-1的浆膜性能和浆液黏附性能,测试了AS-1在不同浆液含固量下浆出纱线的性能及织造效果,并与原用PVA配方的工艺进行了对比.实践证明,AS-1不仅可以完全取代PVA用于细号纯棉色织物的上浆,还可以有效提高织机效率、降低上浆成本.     

新型针织牛仔面料的研发

介绍了开发针织牛仔面料的总体思路,并以添纱鱼鳞面料和添纱斜纹面料为例,阐述了开发此面料的具体实现过程,包括:设备参数、原料、织针排列、三角排列、穿纱方式和面料参数。在此基础上对这两种面料进行了织物性能测试,包括顶破强力、耐磨性能、透气性能测试。分析得出:按照此种思路设计面料时应主要考虑顶破强力和透气性,可通过改变纱线的种类、线密度以及织物组织等因素来实现对这两种性能的调节。