检索结果-南通市图书馆

Formation and Characterization of CdS Hollow structures

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(materials Science) 2008年第3期23卷 425-427页

作者：胡鹏 key laboratory of Fiber Optic Sensing Technology and Information Processing({2. of education) Wuhan University of Technology

CdS hollow structures were built up by using the one pot method and using carbon disulfide （CS2. and ethylenediamine as starting materials. CS2.is insoluble in water and could form metastable oil droplets in the water at a moderate temperature. The oil droplets formed chains in the circumvolving water. CdS crystals grew and mineralized on the surfaces of the CS2.droplet chains, forming CdS shells around the unreacted CS2.cores. After the surrounding temperature was raised above the boiling point of CS2. the unreacted CS2.cores vaporized, leaving the CdS shelled hollow structures. The CdS hollow structures were characterized by using a transmission electron microscope, an X-ray diffractometer, a UV-Visible spectrophotometer and a fluorescence spectrophotometer. The CdS hollow structures were mainly tubes with closed ends. The exterior diameter and the interior diameter of tubes were about 50 nm and about 15 nm, respectively. Compared with the absorption onset wavelength of the bulk CdS, the CdS hollow structures exhibited a blue shift of about 57 nm. While excited at 2.3 nm, the CdS hollow structures emitted greenish blue light centered at 470 nm.

关键词： nanomaterial optical material Cadmium sulfide hollow structure

Spectroscopic Analysis on the Effect of Temperature on Kunitz Domain 1 of Human Tissue Factor Pathway Inhibitor-2

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2007年第6期39卷 406-412页

作者： Chenqi ZHANG~(1#), Desheng KONG~(2.), Xingang LIU~1, Xiaomin YAN~1, Linsen DAI~(1*), and Duan MA~(2.) 1 Center of Analysis and Measurement, Fudan university, Shanghai 2.0433, china 2.{2. laboratory of Molecular Medicine. ministry of education, Fudan university, Shanghai 2.0032. china Center of Analysis and Measurement Fudan UniversityShanghai 200433China keylaboratory of Molecular Medicine Ministry of EducationFudan UniversityShanghai 200032China

The conformation of Kunitz domain 1 of human tissue factor pathway inhibitor-2.(hTFPI-2.KD1) has been studied by Fourier transform infrared spectroscopy, circular dichroism, and Raman spectroscopy. It was found that hTFPI-2.KD1 contained approximately 17% s-helices, 2.% β-strands, 46% random coils, 13% β-turns, and two kinds of disulfide bonds (ggg and tgt) at 2.℃. The detailed conformational changes of the heated protein observed by Fourier transform infrared spectroscopy, circular dichroism and Raman spectroscopy revealed that hTFPI-2.KD1 was thermally stable. However, KD1 could form an intermediate form at high temperature, then return to its normal conformation when the temperature was lowered. Activity assays also showed that hTFPI-2.KD1 was able to keep its inhibitory activity on plasmin after being heated to 80℃ for 5min.

关键词： hTFPI-2.KD1 conformation disulfide bonds thermal stability structure and function

Synthesis,structure and catalytic activity of complexes [Ln(EDBP)_2.DME)Na(DME)_3](Ln=Er,Yb,Sm) for ring-opening polymerization of ε-caprolactone

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Chemistry 2009年第10期52卷 1711-1714页

作者： YU JianFang, WU GuangMing, HUANG Jing, SUN WeiLin & SHEN ZhiQuan key laboratory of Macromolecular Synthesis and Functionalization, {2. of education, Department of Polymer Science and Engineering, Zhejiang university, Hangzhou 31002., china 1. key laboratory of Macromolecular Synthesis and Functionalization Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

Discrete ion-pair complexes [Ln(EDBP)2.DME)Na(DME)3] [Ln=Er (1), Yb (2., Sm (3)] have been synthesized by the reaction between sodium salt of 2.2.-ethylidene-bis(4,6-di-tert-butylphenol)(EDBPH2. and Ln(BH4)3·3THF (Ln=Er, Yb, Sm) followed by centrifugation and recrystalization. The complexes were characterized by elemental analysis and FT-IR, and the bonding model of these compounds was confirmed by X-ray single crystal diffraction for complex 1. It was found that four O atoms in two biphenol ligands as well as two O atoms in one ethylene glycol dimethyl ether (DME) molecule connect to the center rare earth metal atom, while sodium exists as counterpart cation to balance the charge. Complexes 1―3 can all be used as single component initiators for the ring-opening polymerization of ε-caprolactone.

关键词： ring-opening polymerization ε-caprolactone X-ray single crystal biphenol

Influence of the cobalt concentration on optical and magnetic properties of zinc oxide

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第10期55卷 897-901页

作者： WANG LiWei,ZHANG FuJun,XU Zheng,ZHAO SuLing & LU LiFang Institute of Optoelectronics Technology,Beijing Jiaotong university key {2. of Luminescence and Optical Information (Beijing Jiaotong university),ministry of education,Beijing 100044,china Institute of Optoelectronics Technology Beijing Jiaotong University Beijing China ministry of education Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University) Beijing China

A series of Co-doped ZnO thin films have been prepared by direct current reactive magnetron sputtering on glass *** structural characterization by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) gave no evidence of second phase *** qualitative composition and chemical state were characterized by energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectronic spectrometry (XPS),*** results confirmed that Co was incorporated as Co3+,occupying the Zn2. sites in ZnO's wurtzite *** luminescence properties of the films were investigated by room temperature photoluminescence,and the optical properties were studied by optical *** magnetic analysis was carried out at room temperature and at 50 K by Quantum Design MPMS (SQUID) *** results showed that all the Co-doped ZnO thin films prepared by direct current magnetron sputtering were not ferromagnetic above 50 K.

关键词：氧化锌钴氧化物磁性直流反应磁控溅射 X射线光电子能谱室温光致发光扫描电子显微镜纤锌矿结构

Distribution of ammonia-oxidizing Betaproteobacteria community in surface sediment off the Changjiang River Estuary in summer

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2011年第3期30卷 92-99页

作者： LI Jialin BAI Jie GAO Huiwang LIU Guangxing key laboratory of Marine Environmental Science and Ecology of {2. of education College of Environmental Science and Engineering Ocean University of China Qingdao 266100 China Yantai Institute of Coastal Zone Research Chinese Academy of Sciences Yantai 264003 China

The spatial distribution of ammonia-oxidizing Betaproteobacteria （βAOB） was investigated by FISH （fluorescence in situ hybridization） and DGGE （denaturing gradient get electrophoresis） techniques in the sediment off the Changjiang River Estuary. Sediment samples were collected from eight stations in June before the formation of hypoxia zone in 2.06. The abundance of βAOB ranged from 1.87× 10^5 to 3.53×10^5 cells/g of sediment. βAOB abundance did not present a negative correlation with salinity, whereas salinity was implicated as the primary factor affecting nitrification rates. The DGGE profiles of PCR-amplified amoA gene fragments revealed that the βAOB community structure of sample S2.separated from other samples at the level of 40% similarity. The variations in composition ofβAOB were significantly correlated with the salinity, temperature, absorption ability of sediments and TOC. The statistical analysis indicates that theβAOB abundance was a main factor to influence nitrification rates with an influence ratio of 87.7% at the level of 40% biodiversity similarity. Considering the good correlation between βAOB abundance and nitrification estimates, the abundance and diversity of βAOB community could be expected as an indirect index of nitrification activity at the study sea area in summer.

关键词： ammonia-oxidizing Betaproteobacteria (βAOB) diversity abundance nitrification surface sediment Changiiang River Estuarv (CRE)

Fractal model for simulation of frost formation and growth

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第3期53卷 807-812页

作者： LIU YaoMin,LIU ZhongLiang,HUANG LingYan&SUN JunFang education ministry {2. laboratory of Enhanced Heat Transfer and Energy Conservation,College of Environmental and Energy Engineering,Beijing university of Technology,Beijing 10012.,china 1. education ministry {2. laboratory of Enhanced Heat Transfer and Energy Conservation College of Environmental and Energy Engineering Beijing University of Technology Beijing 100124 China

A planar fractal model for simulation of frost formation and growth was proposed based on diffusion limited aggregation(DLA)model and the computational simulation was carried out in this *** changing the times of program running circulation and the ratio of random particles generated,the simulation figures were gained under different conditions.A microscope is used to observe the shape and structure of frost layer and a digital camera with high resolution is used to record the pattern of frost layer at different *** comparing the simulation figures with the experimental images,we find that the simulation results agree well with the experimental images in shape and the fractal dimension of simulation figures is nearly equal to that of experimental *** results indicate that it is reasonable to represent frost layer growth time with the program circulation times and to simulate the frost layer density variation during its growth process by reducing the random particle generation *** feasibility of using the suggested model to simulate the process of frost formation and growth was *** insufficiencies and its causes of this fractal model are also discussed.

关键词： fractal frost formation and growth DLA simulation

Study on Laccase-Catalyzed Oxidation of Disubstituted Ferrocene and π-arene-π- cyclopentadienyliron Derivatives

在线全文

学校读者我要写书评

暂无评论

Wuhan university Journal of Natural Sciences 2000年第3期5卷 351-356页

作者： Ji Li-cai1, Hu Pei-zhi2. Jin Chang-hua3 , Ding Zi-rong2.1. College of Adult education, Wuhan university, Wuhan 430072. {2. 2. Col lege of Chemistry and Environment Science, Wuhan university, Wuhan 430072. C hina 3,Yiping Plant of Chemistry and Industry at Zhong Qing City, Zhong Qing 63132., {2. Wuhan university College of Adult Education Wuhan China (GRID:grid.49470.3e) (ISNI:***) Wuhan university College of Chemistry and Environment Science Wuhan China (GRID:grid.49470.3e) (ISNI:***) Yiping Plant of Chemistry and Industry at Zhong Qing City Zhong Qing China (GRID:grid.49470.3e)

It is studied that Rhus vernicifera laccase catalyzed oxidation of 2. disubstituted ferrocene and its metal complexes, π-arene-π-cyclopentadienyliron derivatives and metal meso-(tetra-4-sulfanatophenyl)porphyrin in the diethylene glycol monobutyl ether (DGBE)/phosphate buffer (V/V, 1/5). It is found that 1,1′-bishydroxylmethyl ferrocene etc 16 compounds are new substrates of laccase. The relation of structure and function of substrates is discussed. The affective factors of laccase-catalyzed oxidation of 1,1′-bishydroxyl-methyl ferrocene—pH, temperature, substrate concentration, laccase quantity and surfactant were investigated further.

关键词： key words Rhus vernicifera laccase disubstituted ferrocene catalytic oxidation π arene π cyclopentadienyliron

Unsteady-State Grinding Technology (I) Theoretical Generalization and Research on Grinding Mechanism

在线全文

学校读者我要写书评

暂无评论

厦门大学学报（自然科学版） 2002年第S1期41卷 46-47页

作者： LIN Bin, LI Zhi-chao, XU Yan-shen, HU Jun (The State education ministry {2. laboratory of High Temperature structure Ceramics and Machining Technology of Engineering Ceramics, Tianjin university, Tianjin 300072. china)

In conventional grinding theory, it is obvious that there must be a very high hardness difference between grains of the grinding wheel and workpieces. The best grinding wheels are those giving the lowest "natural limiting surface roughness" while cutting at appreciable plunge velocities. With the development of new materials and new machining processes, conventional theories of grinding techniques are no longer suitable to explain many phenomena in the course of grinding procedures. In dealing with precision or ultra-precision grinding processes of advanced ceramics, many results of experiments and practical production have shown that grinding with super hard materials wheels is not the only method to machine advanced ceramics. This paper is intended to propose a new grinding theory named as unsteady-state grinding technique evolved from some phenomena that can not be explained by conventional grinding theory. Unsteady-state grinding technique means the technique which can make the surface roughness of the materials, especially hard and brittle, be up to the standard of ultra-precision machining by utilizing common wheels characteristic of inferior self-sharpening and wear-resistance. In the process of machining, the common wheel need to be redressed about 3～5 times and the time between two redressings is about 3～5 minutes. As a validation of the new grinding technology, experimental work was performed to prove the existence of the unsteady state in the process of ultra-precision grinding with common abrasive wheel-pink fused alumina wheel. From the results of the observation of the wheel topography, the whole grinding process in unsteady state was separated into three stages namely cutting by grains peaks, micro-cutting by micro edges of the broken grains and rubbing without material removal, which is different from conventional grinding theory. For the difference of hardness between grinding wheel and workpiece material is not so apparent, some people have doubts

关键词： unsteady state grinding theory grinding mechanism common abrasive wheel ceramic

Spectral wave transformation model for simulating refrac-tion-diffraction with strongly reflecting coastal structures

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2011年第2期30卷 25-32页

作者： ZHENG Jinhai NGUYEN Viet Thanh ZHANG Chi State key laboratory of Hydrology-Water Resources and Hydraulic Engineering HohaiUniversity Nanjing 210098 China College of Harbor Coastal and Offshore Engineering Hohai University Nanjing 210098 China

On the basis of the wave action balance equation which incorporates refraction,diffraction,reflection and wave-current interaction,a directional spectral wave transformation model WABED is developed for predicting the irregular wave refraction-diffraction with strongly reflecting structures in coastal *** the model,diffraction is taken into account by introducing a term formulated from a parabolic approximation wave equation,and reflection is calculated through a back-marching numerical approach at the reflecting *** experimental data sets are used to examine the performance of present model with regard to wave characteristics around reflecting coastal *** is from a physical experiment at idealized inlet with parallel jetties,while the other is from a laboratory study on a coastal project of the concave *** good agreements are found for both cases,revealing the applicability of the present model for predicting combined wave refraction-diffraction processes with strongly reflecting coastal structures.

关键词： Wave Height Coastal structure Spectral Wave Wave Prediction Spectral Wave Model