检索结果-南通市图书馆

A simple solution route to control synthesis of Fe_3._4 nanomaterials at low temperature and their magnetic properties

在线全文

学校读者我要写书评

暂无评论

science China Chemistry 2009年第7期52卷 916-923页

作者： LIU Yi1,2, CHEN Yun1, ZENG YuPing2 & WANG ShiLong3.1 department of Chemistry and chemical Engineering, Zaozhuang university, Zaozhuang 277160, China 2 Shanghai Institute of Ceramics, Chinese Academy of {3.s, Shanghai 200050, China 3.school of Life {3. and technology, Tongji university, Shanghai 200092, China department of Chemistry and chemical Engineering Zaozhuang University Zaozhuang China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai China school of Life science and technology Tongji University Shanghai China

A series of nanostructured iron compounds including cubic Fe3.4 and orthorhombic FeOOH were synthesized via a facile low temperature (in the range of 60-100℃) solution method. In the whole process, the interaction between FeCl2·4H2O and methenamine (C6H12N4) was carried out through a reflux device under different reaction conditions such as temperature, solvent, and duration. The samples were detected by XRD, TEM, SAED, physical property measurement system, and Mssbauer spectroscopy, separately. The experiments showed that magnetic mixture nanoparticles had flake and rod morphologies, and cubic Fe3.4 took on grain nanostructure. Magnetism measurements indicated that the saturated magnetization of the as-obtained magnetic mixture was lower than that of the cubic magnetite. Mssbauer spectroscopy testified the sample consisting of cubic magnetite rather than γ-Fe2O3. In addition, a possible growth mechanism of cubic magnetic nanoparticles under different conditions was discussed.

关键词： magnetic nanoparticles cubic Fe3.4 oxidation-coprecipitation method reflux magnetic properties at room temperature Mssbauer spectrum

Structure and Magnetic Properties of Ni-doped ZnO Powder

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials science) 2010年第5期25卷 770-773页

作者：高放赵俊 department of Electronic science and technology Huazhong University of Science and Technology

Ni-doped ZnO nanopowder （Zn0.98Ni0.2O） was synthesized by improved coprecipitation method. The average particle size of the powder was estimated to be 50 nm. The powder was then processed by thermal treatment. Samples were annealed at 1 073. 1 273. and 1 473.K, respectively. The solubility of NiO in ZnO and the lattice parameters of ZnO both increased with the temperature. The magnetic property of the doped samples was examined, and hysteresis loops were got. The results showed all the samples were ferromagnetic, while powder processed at 1 273.K for 4 h got a highest saturation magnetization （Ms） of 0.0457 emu/g. Also, magnetic properties were related to the grain size of the powder.

关键词： ferromagnetism diluted magnetic semiconductor Ni-doped ZnO coprecipitation solid state reaction

Effect of Cooling Rate on Morphology and Oxygen Permeability of Polypropylene

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 219-223页

作者： Wei Tian Raymond T. Whodhams(Material science and Engineering school, university of science and technology Beijing, Beijing 100083. China)(department of chemical Engineering and Applied Chemistry university of Toronto, Toronto M5S IA4, Canada) Material science and Engineering school University of Science and Technology Beijing Beijing 100083 China department of chemical Engineering and Applied Chemistry University of Toronto Toronto Ont. M5S IA4 Canada

The influence of different cooling rates on the morphology and oxygen permeabilityr of polypropylene containing ferrocene has been investigated. The spherulitic crystalline size and structure, which can affect the oxygen permeability are dependent upon the heating temperature, annealing time and cooling rate. The modulus of the composite was measured b}' dynamic mechanical analysis.

关键词： polypropylene oxygen permeability cooling rate

Assessment of the apparent activation energies for gas/solid reactions—carbonate decomposition

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology Beijing 2003年第2期10卷 25-29页

作者： Jianhua Liu and Jiayun ZhangMetallurgical Engineering school, university of science and {3. Beijing, Beijing 100083. China Metall. Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The guidelines for assessing the apparent activation energies of gas/solidreactions have been proposed based on the experimental results from literatures. In CO_2 free inletgas flow, CaCO_3.decomposition between 950 and 1250 K with thin sample layer could be controlled bythe interfacial chemical reaction with apparent activation energy E = (215+-10) KJ/mol and E=(200+-10) kJ/mol at T = 813.to 1020 K, respectively. With relatively thick sample layer between 793.nd 1273.K, the CaCO_3.decomposition could be controlled by one or more steps involvingself-cooling, nucleation, intrinsic diffusion and heat transfer of gases, and E could vary between147 and 190 kJ/mol. In CO_2 containing inlet gas flow (5 percent-100 percent of CO_2), E wasdetermined to be varied from 949 to 2897 kJ/mol. For SrCO_3.and BaCO_3.decompositions controlled bythe interfacial chemical reaction, E was (213.-15) kJ/mol (1000-13.0K) and (3.5+-15) kJ/mol(1260-1400 K), respectively

关键词： assessment activation energy decomposition carbonate

Synthesis and Lubrication of Phosphorylcholine Derivative

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2010年第3期7卷 254-258页

作者： Zhenliang Qiao~1, Dangsheng Xiong~1, Lude Lu~2, Pengju Jiang~2 1. department of Materials science and Engineering, Nanjing university of science and technology, Nanjing 210094, P.R. China 2. school of chemical Engineering, Nanjing university of science and technology, Nanjing 210094, P. R. China department of Materials science and Engineering Nanjing University of Science and Technology Nanjing P.R. China school of chemical Engineering Nanjing University of Science and Technology Nanjing P. R. China

The monomer of phosphorylcholine derivative, O-(5-（2-methacryloxy）-3. 3.dimethyl-3.azapentyl)-O’-（ω-hydroxy-octyl）-phosphatequaternary ammonium salt, was designed and synthesized successfully. It was characterized by the spectra ofHNMR and Mass spectra （ESI+）, and every signal was assigned. Then the lubricating characteristics of the phosphorylcholinederivative were investigated on the tribological setup of ball-oh-flat. The Ultra-High Molecular Weight Polyethylene（UHMWPE） flat was rotated against a stainless steel ball with 6 mm diameter. The load was 2.3.N, which corresponded to amaximal Hertz contact pressure of 29 MPa. Water, phosphorylcholine derivative, and Acrylic Acid （AA） solution were used aslubricants, respectively. Compared with AA, the phosphorylcholine derivative shows significant lubrication. It can be stronglyhydrated under water due to the charged segment in chemical structure. The thick water layers within the chains serves asboundary lubricants, and this is thought to be the molecular origins of lubricating behavior.

关键词： artificial joint articular cartilage molecular lubrication mechanism phosphorylcholine synthesis UHMWPE

A whisker-like carbon composite for the immobilization of laccase and its bioelectrochemistry

在线全文

学校读者我要写书评

暂无评论

science China Chemistry 2010年第6期53卷 1332-1336页

作者： MA GuoXian1,2,ZHONG QingDong2 & LU TianHong3.1department of chemical Engineering,Shanghai Institute of technology,Shanghai 20023.,China 2{3. of Materials science and Engineering,Shanghai university,Shanghai 200072,China 3.0} of Chemistry,Nanjing Normal university,Nanjing 210097,China department of chemical Engineering Shanghai Institute of Technology Shanghai China school of Materials science and Engineering Shanghai University Shanghai China department of Chemistry Nanjing Normal University Nanjing China

A novel mesoporous carbon/whisker-like carbon (MCWC) composite was used for the immobilization of laccase (Lac) and its bioelectrochemical behaviors were *** was confirmed by XPS that Lac was strongly adsorbed on the surface of the MCWC *** cyclic voltammetric results showed that the immobilized Lac underwent a direct quasi-reversible electrochemical *** value of the electron transfer rate constant ks was estimated to be 0.770 s-1,indicating a reasonably fast electron transfer between the immobilized Lac and the underlying *** surface concentration (I-) of Lac was estimated to be 2.73. × 10-12 mol/*** experimental results showed that the immobilized Lac displayed an appreciable electrocatalytic activity to the electrochemical reduction of *** properties could be attributed to the particular structure of loosely packed nanometer-scale carbon whiskers and the existence of a large amount of oxygen-containing *** immo- bilization method and the novel carrier (MCWC) may find new applications in fabricating the biocatalysts for biofuel cells.

关键词： laccase whisker-like carbon composite direct electrochemical reaction oxygen bioelectrochemistry

Synthesis of vertically aligned carbon nanotube arrays on silicon substrates

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2004年第5期47卷 616-624页

作者： ZHENG Ruiting1, CHENG Guoan1, PENG Yibin1, 2, ZHAO Yong1, 3. LIU Huaping1 & LIANG Changlin1 1. Key Laboratory of Radiation Beam technology and Materials Modification of Ministry of Education, department of Materials science and Engineering, Beijing Normal {3., Beijing 100875, China 2. school of science, Civil Aviation {3. of China, Tianjin 3.03.0, China 3. department of Physics, Nanchang {3., Nanchang 3.0047, China Correspondence should be addressed to Zheng Ruiting Key Laboratory of Radiation Beam technology and Materials Modification of Ministry of Education Department of Materials Science and Engineering Beijing Normal University Beijing China school of science Civil Aviation University of China Tianjin China department of Physics Nanchang University Nanchang China

The growth of well-aligned carbon nanotube (CNT) arrays using a heat chemical vapor deposition system on silicon substrates is reported. The growth properties of CNT arrays are studied as a function of synthesis conditions. It is found that 750°C and 10 nm Fe film are suitable conditions for the growth of well-aligned CNT arrays. CNT arrays with a uniform diameter, thick tube wall and firm cohesion to the Si substrate can be grown for C2H2 concentration of 27%. Based on the experiment, the processes of improving the alignment of CNT arrays and cohesion between CNT arrays and Si substrates are discussed.

关键词： carbon nanotubes, vertically aligned, silicon substrate, chemical vapor deposition.

Synthesis and Characterization of Poly (Aryl Ether Ketone) Containing Phthalazinone and Naphthalene Moieties

在线全文

学校读者我要写书评

暂无评论

Chinese chemical Letters 2000年第9期11卷 777-778页

作者： Ye GAO Xi Gao JIAN Jin Yan WANG department of polymer science, College of chemical Engineering, Dalian {3. of technology, Dalian 116012 department of Polymer science College of Chemical Engineering Dalian University of Technology Dalian 116012 China

A novel poly (aryl ether ketone) (PPEK) containing phthalazinone and naphthalene moieties was prepared by the nucleophilic displacement reaction of 4-(4-hydroxyphenyl) (2H) phthalazin-1-one with 1-chloro-4-(4-chlorobe... 详细信息

关键词： engineering thermoplastics poly (aryl ether ketone) synthesis

Preparation of CuO-CoO-MnO/SiO_2 Nanocomposite Aerogels as Catalyst Carriers and Their Application in the Synthesis of Diphenyl Carbonate

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials science) 2011年第4期26卷 595-599页

作者：赵越卿 school of Light Industry Hebei United University

CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercritical drying （SCD） technique. The effect of synthesis conditions on gelation was investigated. Moreover, the composition of the CuO-CoO-MnO/SiO2 nanocomposite aerogels was characterized by electron dispersive spectroscopy （EDS） and X-ray photoelectron spectroscopy （XPS）, and the specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller （BET） method. Diphenyl carbonate （DPC） as the product was analyzed by gas chromatography （GC）. The experimental results show that the range of optimal temperature for gelation is 3.-45 ℃, and the pH is 3.0-4.5. CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous with a specific surface area of 3.4.9-700.6 m2/g. Compared to CO2 SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71at%-13.77at%. With CuO-CoO-MnO/SiO2 nanocomposite aerogels as catalyst carrier, the yield of DPC is in direct proportion to the atomic fraction of transition metals in the nanocomposite aerogels, and it is up to 26.3. mass%, which is much higher than that via other porous carriers.

关键词： composite aerogel preparation catalyst carrier diphenyl carbonate