高超声速流动研究进展

<正>高超声速的英文名称hypersonic,是钱学森先生1946年命名的。由于洲际导弹、卫星、飞船、航天飞机以及当前国际上十分关心的各种高超声速飞行器的研制需要,过去的半个多世纪,世界大国纷纷投入力量开展高超声速流动研究,使其成为最为活跃的力学研究领域之一。

Analysis of leakage current in GaAs micro-solar cell arrays

The output characteristics of micro-solar cell arrays are analyzed on the basis of a modified model in which the shunt resistance between cell lines results in current leakage. The modification mainly consists of adding a shunt resistor network to the traditional model. The obtained results agree well with the reported experimental results. The calculation results demonstrate that leakage current in substrate affects seriously the performance of GaAs micro- solar cell arrays. The performance of arrays can be improved by reducing the number of cells per line. In addition, at a certain level of integration, an appropriate space occupancy rate of the single cell is recommended for ensuring high open circuit voltages, and it is more appropriate to set the rates at 80%-90% through the calculation.

关于国家自然科学基金生物力学学科优先资助领域的思考

<正>作为我国基础研究最重要的资助机构之一,国家自然科学基金委员会自成立伊始即大力扶持生物力学新兴学科发展、培养和造就生物力学专业人才、推动生物力学研究基地建设,成绩斐然。在科学发展至二十一世纪的今天,针对国际生物力学领域及相关学科发展动态、国家中长期科技发展规划、以及生物力学学科

Characteristics of carbonate content and carbon and oxygen isotopic composition of northern China soil and dust aerosol and its application to tracing dust sources

IEECAS SKLLQG

同位旋非对称核物质性质与扩展的BHF方法(Ⅱ)状态方程、对称能以及三体核力效应

在同位旋相关的BHF理论框架内 ,研究了微观三体核力对非对称核物质状态方程和原子核对称能的影响 .结果表明 :即使引进了微观三体核力后 ,核物质结合能随同位旋非对称度的变化关系仍然能够在整个同位旋自由度范围内(0≤β≤ 1) 相当精确地满足二次方规律 .在核物质饱和密度 ρ0 =0 .17fm- 3处 ,三体核力对于对称能Esym的影响很小 ,考虑三体核力后得到的对称能为 30 .71MeV ,与其经验值符合得很好 ;对于高密度核物质 ,由于三体核力效应 ,对称能明显增大 ,而且三体核力使对称能随密度的增大要比不考虑三体核力情况下的计算结果陡得多 .同时还给出了对称能的密度依赖关系的一个简单的参数化形式 .

Neutron and proton diffusion in fusion reactions for the synthesis of superheavy nuclei

The restriction of the one dimensional (1D) master equation (ME) with the mass number of the projectile-like fragment as a variable is studied, and a two-dimensional (2D) master equation with the neutron and proton numbers as independent variables is set up, and solved numerically. Our study showed that the 2D ME can describe the fusion process well in all projectile-target combinations. Therefore the possible channels to synthesize super-heavy nuclei can be studied correctly in wider possibilities. The available condition for employing 1D ME is pointed out.

SARS起源于污染对病毒进化的加速诱导

针对当前广为流传的SARS病毒“太空起源说”和“野生动物来源说”两种理论 ,本文根据污染进化生态学原理和SARS病毒发病传染特征 ,以有关实验结果为科学依据 ,阐述了SARS病毒的起源问题 ,指出 :我国当前环境日益严重的复合污染为SARS致病病毒的产生提供了适宜的外部生态条件和物质基础 ,SARS致病病毒可能起源于多个病毒的基因重组或融合 ,更可能是一种来自于感冒病毒进化而形成的超级感冒病毒 .可以预料 ,这一推断将为彻底解决SARS的病源提供有价值的理论指导

Separation of enantiomers by nanoliquid chromatography and capillary electrochromatography using a bonded cellulose trisphenylcarbamate stationary phase

A cellulose trisphenylcarbamate-bonded chiral stationary phase was applied to nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) with nonaqueous and aqueous solutions as the mobile phases. Several chiral compounds were successfully resolved on the prepared phase by nano-LC. The applicability of nonaqueous CEC on a cellulose derivative stationary phase was investigated with the organic solvents methanol, hexane, 2-propanol, and tetrahydrofuran (THF) containing acetic acid, as well as triethylamine as the mobile phases. Enantiomers of warfarin and praziquantel were baseline-resolved with plate numbers of 82 300 and 38 800 plates/m, respectively, for the first eluting enantiomer. The influence of applied voltage, concentration of nonpolar solvent, apparent pH, and buffer concentration in the mobile phase on the electroosmotic flow (EOF) and the mobility of the enantiomers was evaluated. Enantioseparations of traps-stilbene oxide and praziquantel were also achieved in aqueous CEC with plate numbers of 111 100 and 107 400 plates/m, respectively, for the first eluting enantiomer. A comparison between nonaqueous CEC and aqueous CEC based on a cellulose trisphenylcarbamate stationary phase was discussed. Pressure-assisted CEC was examined for the chiral separation of praziquantel and faster analysis with high enantioselectivity was acquired with the proper pressurization of the inlet vial.

中国黄土地区耕作侵蚀模拟(英文)

耕作侵蚀是国际上新近开展的一个研究领域。为了对中国黄土地区的耕作侵蚀规律进行定量描述 ,采用施放小立方块作为示踪材料进行耕作试验及测量来示踪和监测土壤运动 ,并通过相关分析与理论推导 ,对该地区的耕作侵蚀进行了模拟 ,获得了能够直接计算出坡面剖面任何一点净侵蚀模数的耕作侵蚀模型 ,结果表明 ,在采用当地由动物牵引的传统犁在坡面上自下而上进行往返横坡等高向下翻土耕作方式下 :1)一次耕作导致的耕层土壤朝坡向方向平均水平运动距离随坡度的变化表现为线性相关 ;2 )一次耕作导致的坡面剖面任何位置耕层断面的净侵蚀模数 ,受土壤容重、耕作深度、土壤与耕作条件决定的系数和地形曲率的影响。