~(40)Ar~(16+)入射金属表面的近红外光谱线发射

速度小于Bohr速度(vBhor=2.9×106m/s)的高电荷态离子40Ar16+(动能EK=150keV,速度v=8.5×105m/s)入射金属(Ni,Mo,Au和Al)表面,同时测量产生的Ar原子近红外光谱线和X射线谱.实验结果表明,低速高电荷态离子在金属表面俘获电子中性化,形成多激发态的Ar空心原子,空心原子退激辐射从近红外光谱线到X射线波段谱线,近红外光谱线辐射强度说明,低速高电荷态离子在金属表面中性化过程中,金属的功函数起着重要作用,进而验证了经典过垒模型.

Theoretical study on spherical proton emission

The proton radioactivity half-lives of spherical proton emitters are investigated within a generalized liquid drop model (GLDM), including the proximity effects between nuclei in a neck and the mass and charge asymmetry. The penetrability is calculated in the WKB approximation and the assault frequency is estimated by the quantum mechanism method considering the structure of the parent nucleus. The spectroscopic factor is taken into account in half-life calculation, which is obtained by employing the relativistic mean field (RMF) theory. The half-lives within the GLDM are compared with the experimental data and other theoretical values. The results show that the GLDM works quite well for spherical proton emitters when the assault frequency is estimated by the quantum mechanical method and the spectroscopic factor is considered.

抗菌肽CP10A在大肠杆菌中的融合表达

CP10A是一种由抗菌肽Indolicine经过序列改造,且对多数革兰氏阳性病源细菌具有较强抗菌活性的多肽序列。研究根据已报道的CP10A氨基酸序列,兼顾大肠杆菌密码子偏好性,设计CP10A的核苷酸序列,利用PCR技术合成相应的DNA序列,后克隆构建重组表达载体pET32a(+)-CP10A,转入大肠杆菌AD494菌株。经IPTG诱导表达和15%SDS-PAGE电泳检测后发现产物以包涵体形式存在,且融合表达量占总蛋白的50%。在变性条件下经Ni-NTA亲合柱层析及复性,最终获得了较高纯度的可溶性重组蛋白。研究首次实现了CP10A抗菌肽在大肠杆菌中的融合表达,为进一步研究其生物学活性及应用奠定了一定的基础,同时也为研究抗菌肽表达提供了一种方法。

森林流域洪涝灾害成因分析与防治对策

森林流域洪涝灾害成因分析与防治对策孙铁珩，裴铁璠张吉娜（中国科学院沈阳应用生态研究所）（辽宁省生态学会）本文所述的森林流域是广义的，系指我国典型敏感带以东广大地区。典型敏感带始于东北西部内蒙东部向西南一直延伸到青藏高原东南部。它是干旱、半干旱与湿润、...

生物制剂对沙土樟子松幼苗光合特性及养分含量的影响

采用盆栽试验研究了Pt菌剂、ABT生根粉、HRC吸水剂和FCS丰产素等生物制剂对沙地樟子松2年生幼苗光合特征和养分含量的影响,结果表明:Pt菌剂(3号)和ABT生根粉与对照相比,显著地促进了樟子松幼苗全株、地下和地上生物量生长,并增加了幼苗的根冠比值,有利地促进幼苗对养分的吸收;Pt菌剂(3号)和ABT生根粉处理的幼苗叶子养分全N、P、K含量显著地高于对照幼苗,促进了幼苗养分的平衡,为提高光合作用能力提供了物质基础;Pt菌剂(3号)和ABT生根粉处理幼苗与对照相比,光合速率和蒸腾效率显著增强。这些是提高樟子松苗木在干旱、半干旱沙地成活生长的生理基础。

优化农业结构推进我国农业现代化进程

２０年前，中国科学院在湖南的桃源、河北的栾城和黑龙江的海伦开始了建立农业现代化综合科学实验基地的工作。第一步是在这三个县进行农业自然资源综合考察和制订农业现代化建设的基本战略和设想。当时这三个县所制订的农业现代化建设基本战略和设想中，都把建立合理的农...

全球环境管理理念对中国的启示

首先介绍了“全球环境管理”(globalenvironmentalgovernance)理念产生的背景、含义与国际发展态势．全球环境管理是一种多元化、多层面、多视角的理念,包括管理全球环境的制度、法则、规范、标准及其过程与行为．国际上,全球环境管理研究已开始从理念探讨向实践转化．在此基础上,概述了中国参与全球环境管理所面对的挑战和机遇．最后提出,为了更加有效地参与全球环境管理,我国应该：重视提炼关键科学问题,加强原始性创新研究；制定我国参与全球环境管理的发展战略；建立长期有效的高端协调机制；完善配套政策与

Effect of binary block-selective solvents on self-assembly of ABA triblock copolymer in dilute solution

We have studied the self-assembly of the ABA triblock copolymer (P4VP-b-PS-b-P4VP) in dilute solution by using binary block-selective solvents, that is, water and methanol. The triblock copolymer was first dissolved in dioxane to form a homogeneous solution. Subsequently, a given volume of selective solvent was added slowly to the solution to induce self-assembly of the copolymer. It was found that the copolymer (P4VP(43)-b-PS366-b-P4VP(43)) tended to form spherical aggregate or bilayer structure when we used methanol or water as the single selective solvent, respectively.

Study of electron transfer across the liquid/ice-like matrix interface by scanning electrochemical microscopy

In this work, we report the findings of a study on scanning electrochemical microscopy (SECM) to investigate the interfacial electron-transfer (ET) reaction between the 7,7,8,8-tetracyanoquinodimethane radical anion (TCNQ(.-)) in 1,2-dichloroethane and ferricyanide in an ice-like matrix (a mixture of insulting ice and conductive liquid) under low temperatures. Experimental results indicate that the formed liquid/ice-like matrix interface is superficially similar in electrochemical characteristics to a liquid/liquid interface at temperatures above -20 degreesC. Furthermore, imaging data show that the surface of the ice-like matrix is microscopically flat and physically stable and can be applied as either a conductive or an insulting substrate for SECM studies. Perchlorate ion was selected as the common ion in both phases, the concentrations of which controlled the interfacial potential difference. The effect of perchlorate concentration in the DCE phase on interfacial reactions has been studied in detail. The apparent heterogeneous rate constants for TCNQ(.-) oxidation by Fe(CN)(6)(3-) in another phase under different temperatures have been calculated by a best-fit analysis, where the experimental approach curves are compared with the theoretically derived relationships. Reaction rate data obey Butler-Volmer formulation before and after the freezing point, which is similar to most other known cases of ET reactions at liquid/liquid interfaces. However, there is a sharp change observed for heterogeneous rate constants around the freezing point of the aqueous phase, which reflects the phase transition. At temperatures below -20 degreesC, surface-confined voltammograms for the reduction of ferricyanide were obtained, and the ice-like matrix became an insulating one, which indicates that the aqueous phase is really a frozen phase.

Discovery of the genes in response to white spot syndrome virus (WSSV) infection in Fenneropenaeus chinensis through cDNA microarray

We used microarray technology to study differentially expressed genes in white spot syndrome virus (WSSV)-infected shrimp. A total of 3136 cDNA targets, including 1578 unique genes from a cephalothorax cDNA library and 1536 cDNA clones from reverse and forward suppression subtractive hybridization (SSH) libraries of Fenneropenaeus chinensis, plus 14 negative and 8 blank control clones, were spotted onto a 18 x 18 mm area of NH2-modified glass slides. Gene expression patterns in the cephalothorax of shrimp at 6 h after WSSV injection and moribund shrimp naturally infected by WSSV were analyzed. A total of 105 elements on the arrays showed a similar regulation pattern in artificially infected shrimp and naturally infected moribund shrimp; parts of the results were confirmed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The up-regulated expression of immune-related genes, including heat shock proteins (HSP70 and HSP90), trehalose-phosphate synthase (TPS), ubiquitin C, and so forth, were observed when shrimp were challenged with WSSV. Genes including myosin LC2, ATP synthase A chain, and arginine kinase were found to be down-regulated after WSSV infection. The expression of housekeeping genes such as actin, elongation factor, and tubulin is not stable, and so these genes are not suitable as internal standards for semiquantitative RT-PCR when shrimp are challenged by WSSV. As a substitute, we found that triosephosphate isomerase (TPI) was an ideal candidate of interstandards in this situation.