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Improving the electrochemical properties of natural graphite spheres by coating with a pyrolytic carbon shell

新型炭材料

Two kinds of modified natural graphite (MNG) spheres with a pyrolytic carbon shell on smooth or granular surface were obtained using fluidized bed chemical vapor deposition of acetylene by adjusting the reaction parameters. The core of the NING has a highly ordered graphite structure and the shell has a disordered structure. Compared with natural graphite (NG) spheres, MNG with a core-shell structure shows improved first cycling efficiency and cyclability. Especially, the NING spheres with a granular surface possess 84% retention of the first discharge capacity after 41 cycles, owing to effective decrease of the contact resistance and increase of contact area between the NING spheres.

关键词: fluidized bed chemical vapor deposition;core-shell structure;pyrolytic;carbon;modified natural graphite;lithium ion secondary battery;lithium-ion batteries;chemical-vapor-deposition;1st-cycle charge loss;anode material;encapsulated graphite;surface-area;infiltration;performance;improvement;pyrocarbon

Improved Nonlinear Equation Method for Numerical Prediction of Jominy EndQuench Curves

SONG Yuepeng , LIU Guoquan , LIU Shengxin , LIU Jiantao , FENG Chengming

钢铁研究学报(英文版)

Without considering the effects of alloying interaction on the Jominy endquench curves, the prediction results obtained by YU Baihai′s nonlinear equation method for multialloying steels were different from those experimental ones reported in literature. Some alloying elements have marked influence on Jominy endquench curves of steels. An improved mathematical model for simulating the Jominy endquench curves is proposed by introducing a parameter named alloying interactions equivalent (Le). With the improved model, the Jominy endquench curves of steels so obtained agree very well with the experimental ones.

关键词: Jominy endquench curve;nonlinear equation method;alloying interaction parameter;computer simulation

1998 COMPREHENSIVE TABLE OF CONTENTS

中国腐蚀与防护学报

N。1Atmospheric Corrosivlty for Steels………………………………………………… .LIANG Caideng HO[I i。-tat(6)Caustic Stress Corrosion Cr。king of Alloy 800 Part 2.The Effect of Thiosul执e……………………………………… KONG De-sheng YANG Wu ZHAO Guo-zheng HUANG De.ltL。ZHANG Yu。。he CHEN She。g-bac(13)SERS slid E16CttOCh6iniC81 Stlldy Of Illhibit1Oli M6ch&tllsth Of ThlollY68 Oil ITOll ID H....

关键词:

不同烷基酰亚胺的合成及对镥的萃取

刘峙嵘 , 周利民 , 李传茂 , 江小昌

稀有金属 doi:10.3969/j.issn.0258-7076.2006.03.021

合成了7种同一系列新型酰亚胺类萃取剂,并运用元素分析、核磁共振、红外光谱、紫外光谱等测试手段对其物化指标进行了表征.萃取性能表明,烷基酰亚胺萃取稀土镥的能力与骨架空间结构有关.直链烷基酰亚胺萃取镥的能力大于相应的支链烷基酰亚胺,而且随链长的增长萃取能力不断增强.利用斜率法,采取直线线性回归求得镥(Ⅲ)与萃取剂基本上以1:2交换.相同条件下,7种酰亚胺类萃取剂分配比的大小顺序为DOI>DDI>DHI>HAI>HIBI>DBI>BIBI.

关键词: 烷基酰亚胺 , 合成 , , 萃取

Structural, mechanical, thermodynamics properties and phase transition of FeVSb

Physica B-Condensed Matter

The structural, mechanical, thermodynamics properties and phase transition of FeVSb are investigated extensively using the first principle calculations and the quasi-harmonic Debye model. From the calculated elastic constants of cubic FeVSb, some other mechanical quantities, such as bulk modulus and Poisson's ratio, are drawn. Surprisingly, it is found that almost all these mechanical quantities are larger than those of CoVSb (Bo Kong et al., J. Alloys Compd. 509 (2011) 2611); the obtained corresponding transition pressure from fcc to hcp is also larger than that of CoVSb. For these distinctions, their complete different electronic and magnetic behaviors in their cubic structures may be responsible. However, in their hexagonal structures, atomic configurations are similar in terms of the analysis of both the ground-state structure and enthalpy-pressure curves. It is also shown that the elastic instability of cubic FeVSb does not appear with pressure upto 120 GPa and should not be a reason for the pressure-induced phase transition. In addition, heat capacity, Debye temperatures, and so on are obtained successfully for cubic FeVSb under the quasi-harmonic Debye model. Furthermore, we attempt to explore the phase diagram of FeVSb with the model. (C) 2011 Elsevier B.V. All rights reserved.

关键词: FeVSb;Mechanical properties;Thermodynamics properties;Phase;transition;Generalized gradient approximation;semi-heusler compounds;ab-initio calculations;electronic-structure;elastic-constants;thermoelectric-materials;transport-properties;crystals;pressure;gap;instabilities

STUDIES ON PRIMARY CRYSTALLIZATION OF RAPIDLY QUENCHED Al-Ni-Cu-Nd METALLIC GLASS BY USING HIGH RESOLUTION TRASMISSION ELECTRON MICROSCOPY

Y.D.Xiao , W.X.Li , D.Jacovkis , M.T.Clavaguera-Mora , J.Rodriguez-Viejo , N.Clavaguera

金属学报(英文版)

Rapidly solidified Al87Ni7Cu3Nd3 metallic glasses, prepared by using melt spinning, were treated under both isothermal and non-isothermal regime. The amorphous rib-bon and the annealed samples were closely examined by means of differential scan-ning calorimetric, conventional X-ray diffraction and high resolution transmission electron microscopy with selected-area electron diffraction, with special interest in pri-mary crystallization into α-Al nanocrystalline particles, in order to understand struc-tural characteristics of Al-based amorphous/nanocrystalline alloys, and nucleation and grain growth mechanism on the nanometer scale during primary crystallization. The results show that, the as-prepared ribbons are fully amorphous and homogeneous in the micron scale, but contain high density of quenched-in clusters or crystallite embryos. Primary crystallization mainly leads to formation of two-phase mixture of α-Al crystal and residual amorphous phase. The annealed ribbons exposed isother-mally at 110℃ for 5, 130 minutes and heated continuously up to less than 310℃ at 40℃/min consist of large amount of α-Al fec crystal nanoparticles dispersed uni-formly in an amorphous matrix. However, a very little amount of finer orthorhombic Al3Ni intermetalics particles exist in the annealed ribbons heated up to 310℃. During primary crystallization, the leading kinetic mechanics to impede growth of the α-Al crustal is soft impinaement, instead of geometric impinqement.

关键词: rapid solidification , null , null

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