检索结果-南通市图书馆

Contributors and potential of hydrocarbon generation of source rocks by solid-state ^(13)C NMR spectroscopy

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第6期42卷 478-481页

作者： WANGZhaoyun, ZHAO Changyi, CHENG Keming and LU Qinghua1. research institute of Petroleum Exploration and Development,{2. National Petroleum Corporation, Beijing 100083,{2.:2. University of Petroleum, Beijing, 100083{2. research institute of Petroleum Exploration and Development China National Petroleum Corporation Beijing China University of Petroleum Beijing China

SOLID-STATE 13C nuclear magnetic resonance （NMR） technique is an effective method to study the texture of material. Under the condition of high magnetic field （400 MHz） and by the application of cross polarization, magic angle spinning （CP/MAS）, total sideband suppression （TOSS）, etc., the content of different textural carbons in kerogen has been quantitatively analyzed by the solid-state 13C NMR spectroscopy of a series of kerogen of thermal simulation samples with Ro value ranging from 0.64% to 1.76%. The results show that

关键词： solid 13C NMR analysis aliphatic carbon potential of hydrocarbon generation of source rocks.

Dislocation Velocity Exponent and the Strain Rate

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2001年第3期17卷 363-366页

作者： Hongyan LIU and Xiaowei WANG International Center for material Physics, institute of Metal {2., Chinese Academy of Sciences, Shenyang 110016, china E-mail: liu@*** Chinese Acad Sci Met Res Inst Int Ctr Mat Phys Shenyang 110016 Peoples R China

The process of dislocation multiplication has been described hv chaos theory, trying to reveal the connection between the microstructures on the mesoscopic scale and the mechanical properties of material on the macroscopic scale. The relationship between the dislocation velocity exponent and the maximum of strain rate is given. The results obtained from logistic equation with exponent and the dislocation multiplication dynamic equation are compared. A scale law in one-dimension-map model with exponent is shown when the exponents of equations are changed.

关键词： Dislocation Velocity Exponent and the Strain Rate

Preparation and Electrocatalytic Activity of Polyaniline-poly (Propylene Oxide) Modified by Pt Nanoparticles

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) 2006年第4期21卷 9-11页

作者：李美超 College of Chemical Engineering and material Science State Key Laboratory Breeding Base of Green Chemistry-Synthesis TechnologyZhejiang University of TechnologyHangzhou 310032China

The preparation and electrocatalytic activity of polyaniline-poly （ propylene oxide ）（ PAN-PPO ） modified by Pt particles （ Pt/ PAN-PPO ） were investigated. Pt/ PAN-PPO was characterized by scanning electron microscopy （SEM） and energy dispersive spectroscopy （ EDS ）. Pt particles on PAN-PPO were in the nanometer range, and dispersed in a three-dimensional distribution on the surface of PAN-PPO film. Compared with polyaniline and glassy carbon modified with Pt particles under the same conditions, Pt/PAN-PPO exhibited a high electrocatalytic activity for lysine oxidation.

关键词： aniline propylene oxide copolymer platinum electrocatalytic activity lysine

Magnetocrystalline Anisotropies of RFe_(10)V_2.(R=Y, Tb, Dy, Ho, and Er) and Their Hydrides

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 1998年第5期14卷 447-450页

作者： Weiren ZHAO Jueyun PING and Ruzhang MA (material Physics Dept., University of Science and Technology Beijing, Beijing 100083, china)(Present address: Central Iron & Steel {2. institute,Beijing 100081, china) material Physics Dept. University of Science and Technology Beijing Beijing 100083 China Central Iron and Steel research institute Beijing 100081 China

The magnetocrystalline anisotropies of RFe10V2.(R=Y, Tb, Dy, Ho and Er) and their hydrides were studied by X-ray diffraction, magnetization and a.c. susceptibility measurements. The uniaxial anisotropy of Fe-sublattice and R-sublattice with positive second order Stevens αJ in RFe10V2.compounds is weakened by hydrogenation, while that of R-sublattice with negative αJ (Er) enhanced. Such a change of anisotropy causes planar-easy magnetic structures in RFe10V2.(R=Tb and Dy) at room temperature and induces spin reorientation in HoFe10V2.after hydrogenation. The change of anisotropy of R-sublattice after hydrogenation may be owed to a decrease of the second order crystalline coefficient.

关键词： Ho and Er and Their Hydrides V2 R=Y Dy Magnetocrystalline Anisotropies of RFe

Influence of MB-value of Manufactured Sand on the Shrinkage and Cracking of High Strength Concrete

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) 2009年第2期24卷 321-325页

作者：王稷良 Key Laboratory of Road Structure and material Ministry of Communications (Beijing) Research Institute of Highway Ministry of Communication

The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack propagation characteristics at the age of 2. hours, and effects on the mechanical properties, dry shrinkage of the harden concrete were tested. The experimental results show that the MB value is not related with the limestone dust content of MS, but in direct proportion to clay content. With the increase of MB value, the concrete workability decreases, and the flexural strength and 7 d compressive strength reduce markedly, whearas the 2. d compressive strength is not affected. When the MB-value is less than or equal to 1.35, the change of the MB-value has a little influence on early plastic cracking and dry shrinkage property of concrete, but when the MB-value is more than 1.35, the tendency of plastic cracking and dry shrinkage is remarkable.

关键词： manufactured sand methylene blue value high strength concrete anti-cracking shrinkage

Effect of UV Irradiation on PAN Precursor Fibers and Stabilization Process

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3期26卷 449-454页

作者：袁慧五 Department of Chemistry and material Naval University of Engineering

A low-cost rout for modification the polyacrylontrile（PAN） precursor fibers was *** approach involved pretreatment PAN precursor fibers with UV irradiation for various periods of time before the fibers were *** effect of UV irradiation on the chemical structure,orientation factor,density,crystallite size and morphology of the fibers in the process of stabilization was characterized by use of fourier transform infrared spectroscopy（FTIR）,float-sink procedure,X-ray diffraction（XRD）,scanning electron microscope（SEM）,*** results showed that UV irradiation could increase the density of the fibers in stabilization *** analysis indicated that the cyclization of nitrile groups was initiated at room temperature by UV *** transformation of C≡N groups to C=N ones was accelerated in the process of *** orientation factor of irradiated fibers was also *** crystallite size was decreased at first and increased later,and the better irradiation time of UV was 3 min according to the XRD *** analysis indicated that irradiation could decrease the internal and surface defects of the stabilized fibers treated at 300 ℃.

关键词： PAN precursor fibers UV irradiation cyclization crystallite size morphology

MICROSTRUCTURE AND TENSILE PROPERTY OF AN AS-CAST DUPLEX STAINLESS STEEL

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第4期14卷 285-290页

作者： P.L. Mao1,2., K. Yang1) and C. Y. Su1) 1) institute of Metal research, The Chinese Academy of Sciences, Shengyang 110016,{2. 2. School of Metal material, Shenyang University of Technology, Shengyang 11002.,{2. institute of Metal research The Chinese Academy of Sciences School of Metal material Shenyang University of Technology

The effect of high temperature solution heat treatment on the microstructure and tensile property of as-cast 0Cr17Mnl4Mo2. duplex stainless steel was investigated. It was found that the morphology of δ-ferrite in the dual phases microstructures changed gradually from dendritic to lamellar and then to spheroidal, and its distribution became more uniform under appropriate treatment. When the treat temperature was lower than 12.0°C, the spheroidal ratio and the homogeneous distribution of δ-ferrite increased with the increase of temperature, which corresponds to a better tensile property. In addition, when the treat temperature reached 12.0°C and above, the microstructure consists of coarse equiaxial δ-ferrite grains with the needle austenite at its boundaries, which results in the decrease of the tensile properties of the steel.

关键词： Mechanical properties Metal castings Microstructure Tensile properties

Frequency characteristic of series piezoelectric sensor and application to the determination of water in organic solvents

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1994年第1期12卷 58-65页

作者： SHEN, Da-Zhong ZHU, Wen-Hong NIE, Li-Hua YAO, Shou-Zhou New material research {2., Hunan University, Changsha, Hunan 410082. china New material research {2. Hunan University Changsha Hunan 410082 China

Theoretical consideration was proposed for the frequency response of a series piezoelectric sensor to the properties of liquid and verified experimentally. This kind of sensor has sensitive and selective frequency response to the permittivity and specific conductivity of solution with excellent stability, and was applied to the determination of micro-content of water in organic solvents. The detection limit is 0.01 g/L in dioxane.

关键词： Piezoelectric quartz crystal chemical sensor micro-water-content

Influence of Solution Treatment on Impact Toughness and Microstructure of Cobalt-free Maraging Steel

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 114-117页

作者： Yu Jianmin1, Li Baocheng1, Zhang Baohong2. Yang Weiyu2.1North University of china, Taiyuan 030051, china 2.ngineering {2. Center of Magnesium-base material Processing Technology, Ministry of Education, Taiyuan 030051, china N Univ china Coll Mat Sci & Engn Taiyuan 030051 Peoples R China Minist Educ Engn Res Ctr Magnesium Base Mat Proc Technol Taiyuan 030051 Peoples R China

The influence of different solution temperature on microstructure and impact toughness of cobalt-free maraging steel 00Ni14Cr3Mo3Ti was investigated by SEM and X-Ray *** experimental results showed that with the solution temperature variation, the martensite morphology has not changed, is still lath *** Laves phase hindered the dislocation movement after 750 ℃ solution heat treatment, which result in a very low impact absorbed energy, the impact fracture has no obvious plastic deformation, with bad *** the solution temperature increased, the undissolved phase gradually dissolved, the impact absorbed energy increased *** the Laves phase dissolved when reach to 900 ℃, the impact absorbed energy reaches the maximum, is 61 *** morphology change from brittle fracture into toughness transgranular fracture with deep dimple. When solution temperature is above 900 ℃, with the solution temperature further increase, austenite grain size increases *** grain diameter of austenite is about 70 μm after 1050 ℃ solution treatment, the density of precipitates on the grain boundary of maraging steel is increase substantially, deformation compatibility deteriorate, which result in the impact absorbed energy decreased *** type becomes transgranular and quasi-cleavage mixed fracture with the characteristics of the river patterns from ductile transgranular fracture.

关键词： cobalt-free maraging steel solution treatment impact toughness separation