检索结果-南通市图书馆

Wet-chemical synthesis and characteristics of Au nanoshell

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2005年第5期48卷 431-435页

作者： LIU Zhongxin1.2. SONG Hongwei1. YU Lixin1.2. YANG Linmei1.2.& PAN Guohui1.2.1. Key Laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, chinese academy of {2., Changchun 1.0033, china 2. Graduate School of the chinese academy of {2., Beijing 1.0039, china 1. Key Laboratory of Excited State Physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences 130033 Changchun China 2. Graduate School of the {1. academy of {2. 100039 Beijing China

Gold nanoshells were prepared by an easy wet-chemical method, with Ag nanoparticles used as the templates. Transmission electron microscopy (TEM) indicated that the shells were sphere in shape, the size was homogenous, being about 2. nm, and no hard ag-glomerates were observed. The plasma resonance absorption of gold was tuned from visible to near-infrared (NIR) with the increased volume of HAuCl4. The temperature grads (?T) of the gold nanoshell hydrosol under the exposure of an 808-nm optical fiber laser with different power den-sities were measured. The highest ?T was 30℃ (5 W/cm2. irradiation area was 2.cm2.. This kind of gold nanoshell hydrosol is a promising material to be used in biomedicine such as photo-thermal cancer therapy, and its special photothermal convert property will photothermally trigger drug release.

关键词： wet-chemical synthesis, Au, nanoshell, NIR absorption, photothermal conversion.

Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

在线全文

学校读者我要写书评

暂无评论

Science china Earth {1. 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2. DING Yihui3 & ZHANG Renhe2.1. Jiangsu Key Laboratory of meteorological Disaster (KLME), Nanjing Institute of Meteorology, Nanjing University of Informa- tion Science and Technology, Nanjing 2.0044, china 2. State Key Laboratory of Severe Weather (LaSW), {2. academy of meteorological sciences, Beijing 1.0081. china 3. National Climate Center, {2. meteorological Administration, Beijing 1.0081. china 1. Jiangsu Key Laboratory of meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing 210044 China 2. State Key Laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing 100081 China 3. National Climate Center Chinese Meteorological Administration Beijing 100081 China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-china Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-china Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-china Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-china Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-china Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-china Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-china Peninsula to South china Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-china Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

Synthesis,characterization,properties and crystal structure of heterometallic 1. coordination polymers {[CuLZn·CuLZn(H_2.)]·H_2.}_n

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2006年第4期49卷 338-344页

作者： TAO Ruojie1. LI Fu’an1. ZANG Shuangquan1. CHENG Yanxiang2.& NIU Jingyang1.1. Chemistry and Chemical Engineering College of Henan University, Kaifeng 475001. {1. 2. Changchun Institute of Applied Chemistry, chinese {2. of sciences, Changchun 1.002., {1. 1. Chemistry and Chemical Engineering College of Henan University Kaifeng 475001 China 2. Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China

Copper-zinc heterometallic 1. chain coordination polymer has been synthesized and characterized by elemental analysis, and IR spectra etc. The crystal structure was determined by single-crystal X-ray diffraction analyses. The title complex is 1. chain coordination polymer with the chemical formula {[CuLZn·CuLZn(H2.)]·H2.}n, where H4L=N-(2.hydroxybenzamido)-N’-(3-carboxy- lsalicylidene)ethylenediamine. Its structural unit is comprosed of two tetranuclear cycles formed by two dissymmetrical tetranuclear units. These units polymerized each other to form 1. chain coordi- nation polymer.

关键词： copper, zinc, heterometallic coordination polymer, crystal structure.

Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Science china Earth {1. 2006年第9期49卷 991-1001页

作者： WU Yanhong1. WANG Sumin1. HOU Xinhua1.3 1. Key Laboratory of Lake Sedimentation and Environment, Nanjing Institute of Geography and Limnology, chinese {1. of {2., Nanjing 2.0008, china 2. Institute of Tibetan Plateau Research, chinese {1. of {2., Beijing 1.085, china 3. Graduate University of chinese {1. of {2., Beijing 1.0039, china 1. Key Laboratory of Lake Sedimentation and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 2. Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 10085 China 3. Graduate University of chinese {1. of {2. Beijing 100039 China

Chronology is the basis for using lacustrine sediments to reconstruct the history of en-vironmental change. Radioactive-nuclides such as 1.C, 2.0Pb and 1.7Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with “dead carbon”, the measured 1.C age is always older than the actual age which is recognized as “reservoir effect”. Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 2.0Pb dating should make sure to select CIC model or CRS model. On the Tibetan Plateau, most of the lakes are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by “dead carbon” on 1.C dating is stronger. Based on the analysis on results of 1.C, 2.0Pb and 1.7Cs of the lacustrine sediments from Co Ngoin, central Tibetan Plateau, we use the simple regression method to re-calculate the 1.C calendar ages, and establish the time sequence for cores CE-1.and CE-2.with result of 2.0Pb CRS model for the upper 35 cm and re-calculated 1.C calendar age for sediments bellow 35 cm. Since 1.00 cal. a BP, sedimentation inter-rupted for more than 1.00 years. According to this time sequence, variations of environmental proxies confidently reflect the major climatic events in Holocene.

关键词： 1.C, 2.0Pb and 1.7Cs, chronology, lacustrine sediments, climatic event, Co Ngoin, central Tibetan Plateau.

Simulating the transfer and fate of hexachlorocyclohexane in recent 50 years in Beijing, china

在线全文

学校读者我要写书评

暂无评论

Science china Earth {1. 2005年第12期48卷 2203-2213页

作者： CAO Hongying1. LIANG Tao1.& TAO Shu2.1. Institute of Geographical {1. and Natural Resources Research, chinese {2. of {1., Beijing 1.01.1. china 2. Laboratory for Earth Surface Processes, Peking University, Beijing 1.0871. china 1. Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. Laboratory for Earth Surface Processes Peking University 100871 Beijing China

Taking Beijing as a study area, a dynamic fugacity model was used to simulate the transfer and fate of technical HCHs according to the physic-chemical properties of the studying environment and HCH isomers. Dynamic changes of the transfer fluxes and concentrations of HCH isomers during 1.52.2.03 were simulated and the model results suggest good agreement between the calculated and measured concentrations of HCH isomers. During 1.52.1.83, the average input and output amount of HCHs through agricultural application and degradation are 1.0 t and 1.0 t respectively. The dominant transfer processes of HCHs in the study area are air-soil deposition, soil erosion and soil-air diffusion, transfer fluxes of these processes are 80 t?a?1. 1. t?a?1.and 1. t?a?1. which account for 92. of total transfer fluxes of HCHs isomers. There were approximately 2.3t HCHs in all environmental compartments of the study area during this period and 97% of which existed in soil compartment. Air and water advection became the dominant input sources of HCHs after 1.84 when the application of technical HCHs was prohib-ited, concentration of HCHs quickly descended to a quite low level in several years. Total amount of HCHs isomers remaining in the study area environment now is less than 5% that before 1.83, and this percentage may descend to 0.5% after 2. years by prediction.

关键词： fugacity model, hexachlorocyclohexane, compartment, transfer flux, fate.

Experimental study of composite medium with simultaneously negative permeability and permittivity

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 64-78页

作者： SUI Qiang1. 2.& LI Fang1.1. Institute of Electronics, {1. academy of {2., Beijing 1.0080, china 2. School of Information, Beijing Broadcasting Institute, Beijing 1.002., china Correspondence should be addressed to Sui Qiang (email: suiqiang@***) Received July 2., 2.03 1. Institute of Electronics Chinese Academy of Sciences 100080 Beijing China 2. School of Information Beijing Broadcasting Institute 100024 Beijing China

This paper focuses on a composite medium structure that exhibits simultan- eously negative values of effective permeability and permittivity, and our experimental study in an anechoic chamber. The experiment results show that the artificial medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous metallic wires, can have a simultaneously negative effective permeability and permittivity within a frequency region in the microwave regime under certain linearly polarized waves.

关键词： permittivity, permeability, negative index of refraction, split ring resonator, LHM, RHM.

Debris Flow Hazard Assessment Based on Support Vector Machine

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural sciences 2006年第4期11卷 897-900页

作者： YUAN Lifeng 1. 2., ZHANG Youshui 3 1. Institute of Mountain Hazards and Environment, {1. academy of {2., Chengdu 61.041. Sichuan, china 2. Graduate University of {1. academy of {2., Beijing 1.0049, china 3. Institute of Geographical {2. and Natural Resources Research, {1. academy of {2., Beijing 1.01.1. china Institute of Mountain Hazards Environment Chinese Academy of Sciences 610041 Chengdu Sichuan China Graduate University of chinese {1. of {2. 100049 Beijing China Institute of Geographical sciences Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

Seven factors, including the maximum volume of once flow , occurrence frequency of debris flow , watershed area , main channel length , watershed relative height difference , valley incision density and the length ratio of sediment supplement are chosen as evaluation factors of debris flow hazard degree. Using support vector machine （SVM） theory, we selected 2.9 basic data of 37 debris flow channels in Yunnan Province as learning samples in this study. We create a debris flow hazard assessment model based on SVM. The model was validated though instance applications and showed encouraging results.

关键词： debris flow hazard assessment support vector machine (SVM)

A predict-correct projection method for monotone variant variational inequalities

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1998年第15期43卷 1264-1267页

作者： HAN Qiaoming 1.and HE Bingsheng 2.1. Institute of Applied Mathematics, {1. academy of {2., Beijing 1.0080, china 2. Department of Mathematics, Nanjing University, Nanjing 2.0093, china Institute of Applied Mathematics Chinese Academy of Sciences Beijing China Department of Mathematics Nanjing University Nanjing China

A predict_correct projection method is presented for solving monotone variant variational inequalities, which could exploit the advantages and overcome the difficulties of both explicit and implicit projection methods.

关键词： variant variational inequality explicit projection method implicit projection method predict_correct projection method.

Compression behavior of Zr_(41.Ti_(1.)Cu_(1.0}5)Ni_(1.)Be_(2..5) bulk metallic glass up to 2. GPa

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1. 2., ZHAN Zaiji 2., LIU Jing 3 , YUN Jinku 1., SUN Liling 2., LIU Riping 1., ZHANG Jun 2.& WANG Wenkui 1. 2.1. Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, china 2. Center for Condensed Matter Physics, Institute of Physics, chinese {2. of sciences, Beijing 1.0080, china 3. BSRF, Institute of High Energy Physics, chinese {2. of sciences, Beijing 1.0039, china 1. Key Laboratory of Metastable Materials Science and Technology Yanshan University 066004 Qinhuangdao China 2. Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 3. BSRF Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

The compression of a Zr41.i1.Cu1.0}5Ni1.Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.