极性分子的碰撞动力学和稀薄极性气体的粘性

按照Enskog-Chapman稀薄气体动力学理论,单原子分子气体的粘性系数为η=5/12 ((πmkT)~(1/2))/(πσ~2Ω~(2,2)

PROSPECTS OF RESEARCH ON CARBON CYCLE IN THE ARCTIC

全球变暖引发了北极地区的快速变化。北极地区苔原冻土带退化、海冰面积退缩和厚度变薄将使北极生态系发生重要变化 ,因而引起碳的生物地球化学循环过程变异。为精确评估北极地区对人为大气CO2 的吸收通量 ,围绕北极苔原、边缘海和极区海域的碳循环研究引起了重视。调查表明 ,北冰洋和亚北冰洋海冰区是海洋吸收大气CO2 的重要汇区 ,北冰洋具有吸收大气CO2 约 1×GtC/a的能力 ,北冰洋夏季冰缘区的长光照和高生产力促进了对大气CO2 的吸收能力 ,北冰洋深水环流和通风作用也有利于表层碳向深水转移。最近有些调查表明 ,如温度继续升高 ,北极苔原有可能从碳汇转变成大气碳源。国际上正加强北极地区碳循环研究的规划和计划 ,企图通过改进现场调查观测手段以及研究方法 ,来定量研究和模式预测变化中北极地区的碳汇潜力及其对地球气候的影响。The Global warming has been causing rapid changes in the Arctic region. Since last decades, more and more evidences have shown that tundra degraded, sea ice's coverage decreased, center Arctic sea ice's thickness reduced, etc. The changes above in the Arctic would influence carbon biogeochemistry. Therefore, an intention has been paid to investigate carbon cycles on tundra, marginal seas and the Arctic Ocean in the Arctic in order to precisely evaluate uptake fluxes of the anthropogenic atmospheric CO 2. Results have suggested that significant regions for ocean's absorption of the atmospheric CO 2 in the Arctic Ocean and subarctic waters. It was estimated that a potential increase uptake CO 2 capacity would be about 1×Gt C a -1 for the Arctic Ocean due to a long solar radiation and high biological production in the marginal regions in summer would drive a biological pump to effectively absorb the atmospheric CO 2. The deep sea circulation and ventilation would also benefit to transfer CO 2 from surface water to deep sea water. Recent investigations have indicated that a possibility might happen that a sink in the tundra regions in the Arctic would be changed to a source of the atmospheric CO 2 when the global temperature to be increasing. An effort has been practiced to enhance the plan and implementation of carbon cycle researches in the Arctic including improving fields observing methods and modeling for forecasting variations and uptake capacity of CO 2 in the Arctic as well as feedback to the global climate.中国首次北极科学考察和第二次北极科学考察资助;; 国家自然科学基金 ( 4 0 2 760 0 1 )资

装配式轻钢组合结构研究现状与发展

我国正在大力推进新型建筑工业化,其主要实现途径是创新发展装配式建筑。装配式轻钢组合结构具有受力高效、抗震节能、绿色环保等优点,主要用于低层和多层建筑,它适应了新型建筑工业化的发展。综述了包括装配式冷弯薄壁型钢结构、装配式轻钢轻混凝土结构、分层装配式轻钢框架-柔性支撑结构以及装配式轻钢组合框架-轻钢组合剪力墙结构在内的典型装配式轻钢组合结构的发展过程、体系构成以及结构抗震性能研究现状等。分析了上述结构的技术特点、标准体系、工业化建造及工程应用情况,提出了装配式轻钢组合结构研究的若干问题,对装配式轻钢组合结构的未来发展方向进行了研究展望

THE PROPERTIES of THE ELECTROCHEMICAL DEPOSITED CdSe NANOCRYSTALLINE THIN FILMSAND THE MACHANISM of DEPOSITION

电化学沉积CdSE纳晶薄膜的性能及沉积机理王维波林瑞峰林原萧绪瑞（中国科学院感光化学研究所，光电化学中心，北京100101）陈旭光杨勇（厦门大学固体表面物理化学国家重点实验室，厦门361005）关键词CdSE纳晶薄膜，电化学沉积，扫描隧道显微镜...? Nanocrystalline CdSe thin Films were prepared by electrochemical deposition.SEM and XRD measurements indicate that this thin Film was composed of CdSe nanocrystalline particles.A blue shiFt in the absorption onset is seen For the thin Film with quantum size eFFects.Laser scanning microzone photocurrent spectra were used to observe the eFFects of microstructure on photoelectrochemical properties of CdSe Film.From the Fractal characteristic of STM images recorded at diFFerent stages of electrochemical deposition.Fractal dimension was calculated to be 1.50.Kinetic clusters aggregation model was suggested For electrochemical deposition of CdSe nanocrystalline thin Film in terms of kinetic theories of Fractal growth.到国家自然科学基金;中国科学院感光化学所光化学开放实验室资

影响三工河干沟春季融雪洪水发生的气象因素

利用三工河流域近山前倾斜平原区气象资料,对发生在1964-2001年期间三工河干沟春季洪水量进行逐步回归分析,得到2个相关性较好的三元模型方程。模型表明,冬季积雪量越大,3月1候前期气温越低,3月2候气温越高,三工河春季洪水量就越大,反之则相反。模型中的2项气象因素是制约三工河干沟发生春洪的主要条件因素,因此,三工河流域开春期前的增温作用是近年来三工河干沟春季洪水量减少的主要原因