检索结果-南通市图书馆

Vertical dynamic and thermodynamic characteristics of urban lower boundary layer and its relationship with aerosol concentration over beijing

在线全文

cnki会议

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第Z2期48卷 25-37页

作者： ZHOU Mingyu, YAO Wenqing, XU Xiangde & YU Haiqing State key laboratory on Severe Weather, chinese {3. of Meteorological Sciences, beijing 100081, china National Marine Environment Forecasting Center, beijing 100081, china National Meteorological Center, beijing 100081, china State key laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China National Marine Environment Forecasting Center Beijing 100081 China State key laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China National Meteorological Center Beijing 100081 China

By utilizing observational data from a 3.5 m tower of the Institute of Atmospheric Physics (IAP), chinese academy of Sciences (CAS) on March 19-29, 2001 and August 11-25, 2003. a comprehensive study was conducted on the vertical dynamical and thermodynamic characteristics of the urban lower boundary layer (ULBL) and its relationship with aerosol concentration over beijing. Firstly, a comparative analysis was made on the gradient data ({3., temperature and humidity), ultrasonic data (atmospheric turbulences) and air-quality observations at different tower heights (47, 120 and 280 m). Secondly, a diagnosis was made to reveal the major features of normalized variances of velocity and temperature, turbulence kinetic energy as well as their relationship with aerosol concentrations. Furthermore, the characteristics of the ULBL vertical structure and the TSP concentration/distribution variations during a sand/dust weather process were also analyzed. The outcome of the study showed that under unstable stratification, the normalized variances of velocity (σu/u*, σv/u*, σw/u*) and temperature (σT/T*) at 47 and 120 m heights fit the Monin-Obukhov similarity (MOS) framework and the fitting formulas were given out accordingly. According to the stratification parameter (z′/L), the stable ULBL could be divided into 2 zones. With z′/L0.1 and the normalized velocity variances tended to increase along with higher stability, but it remained constant for normalized temperature variances. At daytime, the near-surface layer includes two heights of 47 and 120 m, while 280 m has been above it. The ULBL analysis in conjunction with a sand/dust weather process in beijing in March 2001 indicated that the maximum concentration of Total Suspended Particulates (TSP) at 3.0 m reached 913.3.μg/m3.and the particles were transported from the upper to lower ULBL, which was apparently rela

关键词： urban boundary layer, turbulence, aerosol concentration, sand/dust weather.

Structural phase transitions of tellurium nanoplates under pressure

在线全文

学校读者我要写书评

暂无评论

chinese Physics B 2015年第3期24卷 280-283页

作者：李超 Arfan Bukhtiar 沈希孔盼盼王伟鹏赵豪飞姚湲邹炳锁李延春李晓东刘景靳常青禹日成 beijing National laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences beijing key laboratory of Nanophotonics and Ultrafine Optoelectronic Systems Beijing Institute of Technology Institute of High energy Physics Chinese Academy of Sciences

In situ high-pressure angle dispersive x-ray diffraction experiments using synchrotron radiation on Te nanoplates were carried out with a diamond anvil cell at room temperature. The results show that Te-Ⅰ with a trigonal structure transforms to triclinic Te-Ⅱ at about 4.9 GPa, Te-Ⅱ transforms to monoclinic Te-Ⅲ at about 8.0 GPa, Te-Ⅲ turns to rhombohedral Te-Ⅳ at about 23.8 GPa, and Te-Ⅳ changes to body centered cubic Te-Ⅴ at 27.6 GPa. The bulk moduli B0 of Te nanoplates are higher than those of Te bulk materials.

关键词： tellurium nanoplates phase transition high pressure

Ground subsidence development caused by construction and operation of deep gas caverns in rock salt mass

在线全文

学校读者我要写书评

暂无评论

Ground subsidence development caused by construction and ope...

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： He Jianming,Li Xiao & Li Shouding key laboratory of Engineering Geomechanics,Institute of Geology and Geophysics, chinese {3. of Sciences,beijing,china

Strategic energy storage can guarantee the sustainable development of a nation’s *** storage caverns established in rock salt mass have become one of the important means of storing energy because of the very-low permeability and self curing ability of rock ***,ground subsidence will occur due to the obvious creep of rock salt mass and may lead to serious consequences during the period of cavern construction and operation. The main focus of this paper is the numerical modelling of the development of ground subsidence caused by the construction and operation of the Jintan gas storage cavern facility. A finite element method(FEM)analysis was used to simulate the development of the ground *** this simulation,the rock salt mass was modelled as an elastic creep material and the surrounding bedrock was modelled as an elastic *** Jintan gas storage facility is located in Jiangsu province of china and includes several caverns that are generally spaced 90-110 m *** settlement models were developed and the results are presented. The first model(Case 1)considers the case of settlement developed at the ground surface by a single *** second model(Case 2)considers the ground settlement resulting from two adjacent caverns spaced 100 m apart.

关键词：

Multiple factors relating to the rapid expansion of an invasive plant species Ageratina adenophora

在线全文

cnki会议

学校读者我要写书评

暂无评论

Multiple factors relating to the rapid expansion of an invas...

第三届全国生物入侵大会

作者： Rui Wang~1,Yin-zheng Wang~2,Fang-hao Wan~1 1.State key laboratory for Biology of Plant Diseases and Insect Pests,Institute of Plant Protection, chinese {3. of Agricultural Sciences,beijing,100094,china 2.State key laboratory of Systematic and Evolutionary Botany,Institute of Botany,chinese {3. of Sciences,beijing,100093.china

Many ecological and social factors have influenced the rapid invasion and spread of Ageratina. adenophora into the eastern Himalayas,with its heterogeneous natural *** focused on how diverse biological traits may couple with spatiotemporally heterogeneous geography and ecology, and promote rapid *** and temporal distribution data were collected from literature and private and public *** mapped the spatial and temporal distribution of *** in the Hengduan Mountains,then used binary logistic regression to identify variables that contribute to its ***-count statistics were used to analyze geographic *** analyses reveal that water, wind,elevation,and human activities significantly affect the distribution of *** along the Yalongjiang River,Jinshajiang-Yangtze River,Anninghe River,G108 national road and rail line. Invasion occurs in a compact or scattered manner depending on dispersal pathway and times. Biological traits favor dispersal by water and *** activities along roads and rail lines facilitate invasion over high mountains and across river valleys,and provide scope for further natural *** unexpected and rare invasion event resulted from a great flood;this amplified the dispersal ability of this plant both from vegetative propagules and seed production.

关键词： Ageratina adenophora Invasion Dispersal Hengduan Mountains Yangtze River

Quasi-solid-state nanocrystalline TiO2 solar cells using gel network polymer electrolytes based on polysiloxanes

在线全文

cnki会议

学校读者我要写书评

暂无评论

chinese Science Bulletin 2003年第7期48卷 646-648页

作者： LI Weiying, KANG Junjie, LI Xueping, FANG Shibi, LIN Yuan, WANG Guiqiang & XIAO Xurui Center for Molecular Science, Institute of Chemistry, chinese academy of Sciences, beijing 100080, {3. 1. Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

A quasi-solid-state dye-sensitized nanocrystal-line porous TiO2 film solar cell was fabricated using a novel gel network polymer electrolyte based on polysiloxanes with both polyethylene oxide internal plasticized side chains and quaternary ammonium groups. The cell exhibited better photoelectrical conversion performance under 60 mW/cm2 irradiation. The short photocurrent (Isc) of 5.0 mA/cm2 and open voltage (Voc) of 0.68 V were achieved, and the energy conversion efficiency (h ) and fill factor (ff) were 3.4% and 0.60, respectively.

关键词：类固态TiO2太阳能电池凝胶网状聚合体电解液染色敏化二氧化钛薄膜

在线全文

学校读者我要写书评

暂无评论

强辐射催化法提纯多晶硅

物理学报 2011年第7期60卷 895-919页

作者：陈应天何祚庥中国科学院理论物理研究所北京100190

将低纯度的金属硅,提纯成可用于制造太阳能电池的高纯硅材料的主要关键,是去除材料中的硼杂质.本文提出了一种采用特殊的造渣过程以去除硼杂质的新方法.在这种新方法中,为了促进快速的化学反应,采用高密度的光子作为催化剂,以达到太阳... 详细信息

将低纯度的金属硅,提纯成可用于制造太阳能电池的高纯硅材料的主要关键,是去除材料中的硼杂质.本文提出了一种采用特殊的造渣过程以去除硼杂质的新方法.在这种新方法中,为了促进快速的化学反应,采用高密度的光子作为催化剂,以达到太阳能级硅材料的标准.本文对使用这种新的强辐射催化法炼硅的高温工具、冶炼方法、材料配方、材料的混合、以及渣剂的分离等关键技术,进行了详尽的公开和讨论,并在强辐射光催化原理的研究方面提出了一些探索性的机理.为了方便读者使用本文所提出的方法,建立起一套完整的提炼太阳能级硅材料的工业系统,本文也就去硼后的硅材料中去磷的冷阴极电子束的方法,以及采用磁悬浮无坩埚的定向凝固方法去除金属,提出了一些新的设计和建议.关于本文所提出的方法是否能扩展到电子级硅材料的冶炼工业,本文所提出的无光象定日镜能否扩展应用于其他太阳能光热领域,以及所提出的宏观光化学催化假设能否获得更多的实验验证等,也试图进行了一些进一步的讨论.希望本文所提出的方法,能够在全球科学家们所孜孜以求的低碳、低成本的太阳能产业的巨大努力中,走出一条同传统方法不同的道路.

关键词：多晶硅提纯光催化太阳炉除硼除磷多晶硅

Thermal behavior of zirconia-doped mullite gel fibers

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2012年第3期22卷 213-218页

作者： Wei Wang a,b, Duan Weng a, Xiaodong Wu a a State key laboratory of New Ceramics and Fine Process, Department of Materials Science and Engineering, Tsinghua University, beijing 100084, {3. b The Second Artillery NCO academy of PLA, Qingzhou, Shandong 262500, {3. [a] State key laboratory of New Ceramics and Fine Process Department of Materials Science and Engineering Tsinghua University Beijing 100084 China [b] The Second Artillery NCO academy of PLA Qingzhou Shandong 262500 China

The zirconia-doped mullite gel fibers were prepared via a sol-gel method. The thermal behaviors of the gel fibers during pyrolysis were investigated by means of thermal gravity-differential scanning calorimetry (TG-DSC), in-situ fourier transform infrared spectroscopy (in-situ FTIR), X-ray diffraction (XRD) and transmission electron microscope (TEM). It was found that the mass loss during calcination can be divided into two stages, i.e. 50% below 400 ℃ and 3. during 550-700 ℃. The three exothermic peaks in DSC curves were attributed to the burning of organics, decomposition of nitrates and mullite transformation, respectively. H2O, CO2 and NO2 were generated during the pyrolysis of mullite gel fibers, and the concentration of NO2 was higher than CO2. The activation energy (Ea) of mullite transformation was calculated by a non-isothermal method, which was the smallest for the 1% ZrO2-doped gel fiber (1145 kJ/mol).

关键词： Mullite fiber Zirconia doping Thermal behavior Activation energy

Stabilization of the Nonlinear Elastodynamic System with A Boundary Dissipation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Stabilization of the Nonlinear Elastodynamic System with A B...

第二十七届中国控制会议

作者： Zhang Zhifei,Yao Pengfei key laboratory of Control and System academy of Mathematics and Systems Science,{3. academy of Sciences,beijing 100080,P.R.china

We consider the existence of global solutions of the nonlinear elastodynamic system with a boundary dissipation structure when initial data are *** medium material is assumed to be isotropic and *** show the existence of global smooth *** particular,we obtain the exponential decay of the energy,which implies the exponential stabilization of the system by boundary feedback.

关键词： Nonlinear elastodynamic systems energy estimate Dissipative boundary structure

在线全文

cnki会议

学校读者我要写书评

暂无评论

新能源分布式发电系统的控制策略

太阳能学报 2006年第7期27卷 704-708页

作者：王健康龙云曹秉刚王昆清华大学汽车工程系汽车安全与节能国家重点实验室西安交通大学机械电子工程系天津职业大学经济与管理学院

针对新能源分布式发电系统提出了一种新的能量控制策略。基于飞轮储能系统里矢量控制的感应电机,建立了系统的数学模型。在系统里,采用模糊控制算法实现直流总线电压的自动调整,达到稳定系统的直流总线电压的目的。实验结果证明,在风力... 详细信息

针对新能源分布式发电系统提出了一种新的能量控制策略。基于飞轮储能系统里矢量控制的感应电机,建立了系统的数学模型。在系统里,采用模糊控制算法实现直流总线电压的自动调整,达到稳定系统的直流总线电压的目的。实验结果证明,在风力发电和飞轮储能联合系统的能量控制过程中使用模糊控制算法,实现了能量的快速存储和释放,起到了稳定系统电压的作用,取得了满意的控制效果。

关键词：新能源分布式发电模糊控制能量控制