微囊藻毒素的产生、检测和毒理学研究

国家自然科学基金项目39730380资助; 中国科学院重点项目资助KZ952—S1—120

蓝藻高CO_2需求突变株的研究进展

“海洋863”项目(819-03-03-4); 曾呈奎海洋科学基金; 武汉市“晨光计划”的资助

Hybrid cytomegalovirus-U6 promoter-based plasmid vectors improve efficiency of RNA interference in zebrafish

Short hairpin RNA (shRNA) directed by RNA polymerase III (Pol III) or Pol II promoter was shown to be capable of silencing gene expression, which should permit analyses of gene functions or as a potential therapeutic tool. However, the inhibitory effect of shRNA remains problematic in fish. We demonstrated that silencing efficiency by shRNA produced from the hybrid construct composed of the CMV enhancer or entire CMV promoter placed immediately upstream of a U6 promoter. When tested the exogenous gene, silencing of an enhanced green fluorescent protein (EGFP) target gene was 89.18 +/- 5.06% for CMVE-U6 promoter group and 88.26 +/- 6.46% for CMV-U6 promoter group. To test the hybrid promoters driving shRNA efficiency against an endogenous gene, we used shRNA against no tail (NTL) gene. When vectorized in the zebrafish, the hybrid constructs strongly repressed NTL gene expression. The NTL phenotype occupied 52.09 +/- 3.06% and 51.56 +/- 3.68% for CMVE-U6 promoter and CMV-U6 promoter groups, respectively. The NTL gene expression reduced 82.17 +/- 2.96% for CMVE-U6 promoter group and 83.06 +/- 2.38% for CMV-U6 promoter group. We concluded that the CMV enhancer or entire CMV promoter locating upstream of the U6-promoter could significantly improve inhibitory effect induced by the shRNA for both exogenous and endogenous genes compared with the CMV promoter or U6 promoter alone. In contrast, the two hybrid promoter constructs had similar effects on driving shRNA.

Bulge testing and fracture properties of plasma-enhanced chemical vapor deposited silicon nitride thin films

The mechanical properties and fracture behavior of silicon nitride (SiNx) thin film fabricated by plasma-enhanced chemical vapor deposition is reported. Plane-strain moduli, prestresses, and fracture strengths of silicon nitride thin film; deposited both oil a bare Si substrate and oil a thermally oxidized Si substrate were extracted using bulge testing combined with a refined load-deflection model of long rectangular membranes. The plane-strain modu i and prestresses of SiNx thin films have little dependence on the substrates, that is, for the bare Si substrate, they are 133 +/- 19 GPa and 178 +/- 22 MPa, respectively, while for the thermally oxidized substrate, they are 140 +/- 26 Gila and 194 +/- 34 MPa, respectively. However, the fracture strength values of SiNx films grown on the two substrates are quite different, i.e., 1.53 +/- 0.33 Gila and 3.08 +/- 0.79 GPa for the bare Si substrate a A the oxidized Si substrate, respectively. The reference stresses were computed by integrating the local stress of the membrane at the fracture over the edge, Surface, and volume of the specimens and fitted with the Weibull distribution function. For SiNx thin film produced oil the bare Si Substrate, the Volume integration gave a significantly better agreement between data and model, implying that the volume flaws re the dominant fracture origin. For SiNx thin film grown on the oxidized Si substrate, the fit quality of surface and edge integration was significantly better than the Volume integration, and the dominant surface and edge flaws could be caused by buffered HF attacking the SiNx layer during SiO2 removal. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

MnSi similar to 1.73 grown on silicon with mass-analyzed low energy dual ion beam epitaxy technique

Semiconducting manganese silicide, Mn27Si47 and Mn15Si26, were obtained using mass-analyzed low energy dual ion beam epitaxy technique, Auger electron spectroscopy depth profiles showed that some of the Mn ions were deposited on single-crystal silicon substrate and formed a 37.5 nm thick Mn film, and the other Mn ions were successfully implanted into the Si substrate with the implantation depth of 618 nm. Some samples were annealed in the atmosphere of flowing N-2 at 840 degreesC. X-ray diffraction measurements showed that the annealing was beneficial to the formation of Mn27Si47 and Mn15Si26 (C) 2001 Published by Elsevier Science B.V.

Investigation on quality of cubic GaN/GaAs(100) by double-crystal X-ray diffraction

Cubic GaN was grown on GaAs(100) by low pressure metal organic chemical vapor deposition (MOCVD). X-ray diffraction, scanning electron microscope (SEM) and photoluminescence (PL) spectra were performed to characterize the quality of the GaN film. The PL spectra of cubic GaN thin films being thicker than 1.5 mu m were reported. Triple-crystal diffraction to analyze orientation distributions and strain of the thin films was also demonstrated.

一类基于混沌函数的分组密码的安全性评估

评估了一类基于混沌函数的分组密码（generalized Feistel structure,简称GFS）抵抗差分密码分析和线性密码分析的能力，如果轮函数是双射且它的最大差分特征概率和线性逼近概率分别是p和q，则r轮GFS的最大差分特征和线性逼近的概率分别以p^r-1和q^r-1为其上界。

土壤种子库研究进展

在浏览国内外大量文献的基础上,从土壤种子库研究意义、国内外研究现状和目前研究的热点问题等方面论述土壤种子库的研究进展。针对目前土壤种子库研究的热点问题,主要从土壤种子库的分类、种子质量和种子休眠之间的关系、种子库的水平分布及种子库与地上植被的关系等方面进行讨论,指出其在遗传结构和扩散等研究内容及方法方面所存在的问题,并提出了相应的建议。

Phase diagrams for the MOVPE growth of ZnTe and ZnSeTe

The phase diagrams for the MOVPE growth of ZnTe and ZnSeTe have been proposed for the first time, based on the thermodynamic equilibrium established at the solid-vapor interface, The regions for the single condensed phase of ZnTe(s) and of ZnSeTe(s) have been investigated, respectively, Additionally, the growth conditions of appearance for the double condensed phase of ZnTe(s) + Zn(s or l) and ZnTe(s)+ Te(s or l) for the ZnTe system, of ZnSeTe(s) + Zn(s or l) and ZnSeTe(s)+ Te(s or l) for the ZnSeTe system are discussed.

折射微光学结构出射复杂光学波前

通过单掩模紫外(UV)光刻、感应耦合等离子体(ICP)刻蚀及KOH:H_2O化学腐蚀,在硅片上制作5×5元面阵硅折射微光学结构.通过电化学方法将制成的硅精细图形结构转换成镍版,进而通过压制法将精细的镍版图形进一步转印到有机玻璃材料上,从而制成面阵光学波前出射结构.光刻版由结构尺寸在微米量级的大量微孔组成,其特征尺度和排布方式由算法生成.微形貌测试显示了制作的折射微光学波前出射结构具有预期的表面形貌特征.通过常规光学测试,比较和分析了出射复杂波前的情况.