国家主权财富基金的投资特点及其对国际货币体系与金融市场的影响

国家主权财富基金按来源可分为两类,一类来源于资源性商品出口所得外汇,一类则是以国家的官方外汇储备转移为基础而建立的.主权财富基金的目的主要有三个:平滑经济周期、分散风险和取得相对外汇储备更高的收益率.主权财富基金的投资组合表现出来的特点是本土性倾向、以北美和欧洲为主要国际投资区域、偏重大盘股和金融行业,并表现出多元化趋势.从其投资和运行特点来看,主权财富基金更可能维持甚至促进现有的国际货币体系的延续,而对金融市场则更有可能产生积极的稳定作用.     

Rainfall Assimilation Using a New Four-Dimensional Variational Method: A Single-Point Observation Experiment

Accurate forecast of rainstorms associated with the mei-yu front has been an important issue for the Chinese economy and society.In July 1998 a heavy rainstorm hit the Yangzi River valley and received widespread attention from the public because it caused catastrophic damage in China.Several numerical studies have shown that many forecast models,including Pennsylvania State University National Center for Atmospheric Research's fifth-generation mesoscale model (MM5),failed to simulate the heavy precipitation over the Yangzi River valley.This study demonstrates that with the optimal initial conditions from the dimension-reduced projection four-dimensional variational data assimilation (DRP-4DVar) system,MM5 can successfully reproduce these observed rainfall amounts and can capture many important mesoscale features,including the southwestward shear line and the low-level jet stream.The study also indicates that the failure of previous forecasts can be mainly attributed to the lack of mesoscale details in the initial conditions of the models.     

Facile Synthesis of Gold Nanoparticle-loaded Carbon Nanofiber Composites and Their Electrocatalytic Activity Towards Dopamine, Ascorbic Acid and Uric Acid

A facile approach for the synthesis of gold nanoparticle-loaded carbon nanofiber(Au/CNF) composites was developed. When applied to electrochemistry, these composites showed attractive performances such as high conductivity and facile electron transfer kinetics. Under physiological conditions, the Au/CNF composite modified electrode exhibits highly electrocatalytic activity for the oxidation of dopamine, ascorbic acid and uric acid. Owing to the good selectivity for the simultaneous detection of these three species, the novel composites are promising for the development of effective electrochemical biosensors.     

Lectin Conjugated Gold Nanoparticle-based Colorimetric Assay for Studying the Interactions of Antibiotic with Living Cell

The interactions of antibiotic with living cells were studied by lectin conjugated gold nanoparticles(GNPs)based colorimetric assay. Because of the high affinity of lectin for saccharides, the lectin conjugated GNPs are able to employ as indicators for monitoring the antibiotic induced changes of glycosyl complexes. The interactions of a well known antibiotiC., tunicamycin, with two different cell lines, HeLa and SHG-44, were selected to establish this assay.In the presence of tunicamycin, the dose-and time-dependence on the decreasing of binding affinity of lectin conjugated GNPs with living cells were demonstrated by conventional microscopic and UV-Vis spectroscopic studies. The experimental result demonstrates that our approach can be used to identify antibiotic induced expression difference of glycosyl complexes on different cellular surfaces and determine drug activity quantitatively. For further confirming the capability of the GNP-based assay, the system was also studied by confocal laser scanning microscopy(CLSM)and classic flow cytometry(FCM) assay, and satisfactory results were obtained.     

Electrochemical analysis of dye adsorption on aligned carbon nanofiber arrays coated with TiO2 nanoneedles for dye-sensitized solar cell

An electrochemical method has been developed to analyze dye absorption on the aligned carbon nanofiber arrays coated with TiO2 nanoneedles for dyesensitized solar cell. The unique nanostructure with the roughness factor of 90.6 provides a large effective surface area for dye adsorption. The experimental results showed that the dye molecules cover 39.7% of the TiO2 surface area which influences the performance of dye-sensitized solar cell. The electrochemical method provides the information of the coverage of dye molecules which is a key issue to optimize solar cell performance.     

Facile solvothermal synthesis and photoconductivity of one-dimensional organic Cd(Ⅱ)-Schiff-base nanoribbons

One-dimensional (1D) organic nanoribbons built on N-p-nitrophenylsalicylaldimine cadmium complex were synthesized via a facile solvothermal route. Scanning electron microscope images revealed that the as-synthesized products were ribbon like with widths of 500 nm,thicknesses of about 50nm, and lengthes up to several hundred micrometers. Fourier transform infrared spectrum was employed to characterize the structure. The conductivity of a bundle of nanoribbons was also measured,which showed that Schiff base cadmium nanoribbons had good photoconductive property. This work might enrich organic photoconductive materials and be applicable in nano photoswitch devices in the future.     

指向标识设置间距及设置位置对路效率影响的虚拟研究

为研究在有岔道口的通道上标识设置对行人寻路效率的影响,本文利用Quest3D软件构建虚拟空间,在虚拟空间中对上述问题展开实验研究.通过分组实验的方式,让不同组的实验者在不同标识设置参数的虚拟空间中行走,并采集实验者的实验数据,实验数据显示当标识间距大于50m时或者标识缺失而不远处有类似标识影响时寻路效率会明显下降.因此在有岔道口的通道上标识的设置距离应当小于50m,同时合理设置标识位置,防止与寻路无关的类似标识进入行人视线.     

基于轨迹模式空间解耦及模式能量序列的振荡分析(三)时变性分辨率从摆次细化到时间断面

系列文章的前两篇以振荡模式的空间解耦代替频域解耦,并通过互补群模式的摆次能量演化来反映复杂振荡行为的特征。由于其对时变性的分辨率较低,也不利于讨论多模式之间的交互作用,故文中提出在每个积分步末端所对应的时间断面处,按实际变量值重新冻结映象系统的非哈密顿因素,按虚构的哈密顿系统来估计该断面后的不平衡功率-转角的曲线。进而评估各互补群模式的振荡总能量(或其裕度)的时间序列,将轨迹振荡能量序列分析方法的时间分辨率从按模式摆次细化为按积分步长,更好地反映振荡的局部时变性。针对分别计及调速器或计及机械功率周期性扰动的两个算例,揭示了系统“反常”振荡行为的机理。     

Recrystallization Behavior of Deformed Austenite in High Strength Microalloyed Pipeline Steel

 Using methods of single hit hot compression and stress relaxation after deformation on a Gleeble 1500D thermomechanical simulator, the curves of flow stress and stress relaxation, the microstructure and the recrystallization behavior of Nb V Ti high strength microalloyed low carbon pipeline steel were studied, and the influence of the thermomechanical treatment parameters on dynamic and static recrystallization of the steel was investigated. It was found that microalloying elements improved the deformation activation energy and produced a retardation of the recrystallization due to the solid solution and precipitation pinning. The deformation conditions such as deformation temperature, strain, and strain rate influenced the recrystallization kinetics and the microstructure respectively. Equations obtained can be used to valuate and predict the dynamic and static recrystallizations.