马保国
,
许婵娟
,
钟开红
,
蹇守卫
,
李相国
材料科学与工程学报
doi:10.3969/j.issn.1673-2812.2005.04.006
本文系统地研究了F、S、P元素对水泥熟料矿物形成过程和组成的影响及其叠加矿化效应,并通过化学分析和XRD分析探讨了其作用机理.研究结果表明:F、S、P元素在水泥烧成中均可降低液相出现和C3S形成温度,改善易烧性,但F、S叠加矿化效果最好,而且可以改善熟料的矿物组成及性能,避免了单掺F造成的熟料活性降低等问题.
关键词:
矿化效应
,
氟石膏
,
磷石膏
,
易烧性
YU Qingbo
,
LU Zhongwu
,
CAI Jiuju
钢铁研究学报(英文版)
From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship between material flow and the energy intensity is useful to save energy in steel industry. Based on the concept of standard material flow diagram, all possible situations of ferric material flow in steel manufacturing process are analyzed. The expressions of the influence of material flow deviated from standard material flow diagram on energy consumption are put forward.
关键词:
steel manufacturing process;material flow;energy consumption;calculating method
International Journal of Hydrogen Energy
A modified layered ternary compound (Ti0.98Nb0.02)(3)(Si0.95Al0.05)C-2 was evaluated as a new interconnect material for intermediate temperature solid oxide fuel cells (IT-SOFC). The results indicated that the compound has low density (4.50 g/cm(3)), closer matched thermal expansion coefficient with Y2O3 stabled ZrO2 (9.0 x 10(-6)/K), low room temperature electrical resistivity (24 mu Omega cm), and good mechanical properties and machinability. During the isothermal oxidation at 600 degrees C-800 degrees C, a monolithic layer with the mixture of rutile TiO2 and amorphous SiO2 formed on (Ti0.98Nb0.02)(3)(Si0.95Al0.05)C-2. Its oxidation kinetics roughly follows a parabolic law, the rate constant is 0.45, 1.26, 1.57 x 10(-7) mg(2)/cm(4) s at 600 degrees C, 700 degrees C, 800 degrees C, respectively. After the oxidation at 700 degrees C and 800 degrees C in air for 100 h, its area special resistance is 5 and 12 m Omega cm(2) at the corresponding oxidation temperature, respectively. In oxidizing environment, (Ti0.98Nb0.02)(3)(Si(0.95)A(10.05))C-2 is very stable, and has not Cr or other element volatilization. All above determined properties of (Ti0.98Nb0.02)3 (Si0.95Al0.05)C-2 are favorable for its application as interconnect in IT-SOFC. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
关键词:
MAX phase;Interconnect;SOFC;Oxidation;Area specific resistance;oxide fuel-cells;alloy interconnects;air
Communications in Theoretical Physics
In the weakly coupled electron-phonon systems, the existing theory pointed out that the energy spectra of polaron include four electronic bound states. Our work shows that, due to the non-nearest neighbor hopping interactions, the electron-hole symmetry of the energy band structure implied by SSH model is broken, and the numbers of the bound electronic states are changed. For a negative charged polaron, one new bound state is found near the bottom of conduction band, and the original two bound states below the bottom of the valence band and above the top of the conduction band disappear. For a positive charged polaron, five bound states have been found: one of them is an additional bound state at the top of the conduction band, the others are just the states found in the SSH model. Besides, the energy gap 2 Delta is slightly shifted by turning on the long-range hopping interactions.
关键词:
soliton
Advanced Functional Materials
A new hybrid electrochemical cell incorporating aligned titania nanotubes (ATNTs) as the anode and ordered mesoporous carbon (OMC) as the cathode is demonstrated. The concept is characterized by the optimization of ionic transport in the anode and ionic uptake in the cathode. The ionic transport in the anode can be enhanced by reducing the tube length and wall thickness of the ATNTs. The ionic transport and uptake at the cathode is significantly improved by the combination of ordered mesopores and high specific surface area in the OMC. Remarkably, these hybrid electrochemical energy storage cells are capable of delivering a high energy density of 25 W h kg(-1) and a high power density of 3000 W kg(-1) at a short current-draining time of 30s, more than two times higher than in previously reported hybrid cells. Another advantage of these hybrid cells is that they are safe and stable for long periods of operation owing to the absence of dendrite lithium metal and a solid electrolyte interphase. In terms of the fundamental electrochemistry, the superior performance of the hybrid cells is attributed to shortened electrolyte penetration depth and lithium ion diffusion distance in the ATNT anode, facilitating an effective lithiation anode process, and to the fast anion uptake at the cathode.
关键词:
rechargeable lithium batteries;ordered mesoporous carbons;tio2;nanotubes;li-insertion;rutile tio2;supercapacitors;transport;electrodes;system;cells
Journal of Physical Chemistry C
Sufficient understanding of surface chemistry for electrode and electrolytes during an electrochemical process is a crucial issue to further improve the performance of lithium ion batteries (LIB). In this study, we systematically investigate the interaction between propylene carbonate (PC)-based electrolytes and graphite anode material, which has been under dispute for a long time in the electrochemical community, and a new physical model is proposed to explain the poor compatibility of PC with graphite. With the aid of scanning electron microscopy, focused ion beam workstation, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and thermogravimetry-differential scanning calorimetry, the cumbersome but intriguing questions on the poor compatibility are addressed: (i) Does PC truly have the ability to co-intercalate into graphite materials? Our answer is yes. (ii) Where is the intercalation site? It is around the crystal boundary. (iii) Why does the co-intercalation occur for PC not ethylene carbonateanother kind of useful electrolyte in LIB, since both of them have a similar molecular structure? The methyl group in the PC molecule is the main wire-puller, which makes decomposition products of PC puffed and thus incompetent in inhibiting the subsequent co-intercalation. Finally, three feasible strategies to overcome the poor compatibility are summarized.
关键词:
surface-film formation;electrochemical intercalation;negative;electrode;natural graphite;alkyl dicarbonates;vinylene carbonate;xps;analysis;high-power;li;cells
Materials Research Innovations
Cu/Ti3SiC2 composite, a new electrofriction material, was prepared, for the first time, by PM method. The microstructure, mechanical and electrical properties of the Cu/Ti3SiC2 composites were investigated and were compared with those of Cu/graphite composites. The results demonstrated that Cu/Ti3SiC2 composites had superior mechanical properties over Cu/graphite composites. At filer content of less than 20 vol%, the electrical conductivity for Cu/Ti3SiC2 composites was higher than that for Cu/graphite composites; at high filer content, the electrical conductivity for Cu/Ti3SiC2 composites was lower than that for Cu/graphite composites because of the presence of residual pores. It was found that like Cu/graphite composite, Cu/Ti3SiC2 was a self-lubricated material. The compressive yield strength, Brinell hardness, relative ratio of compressive for Cu-30 vol% Ti3SiC2 composites are 307 MPa, 140, 15.7% respectively.
关键词:
electronfriction material;copper;Ti3SiC2;graphite;composite;self-lubricating;ti3sic2
Huixue JIANG
金属学报(英文版)
A new composite material consisting of 1xxx aluminum alloy and 7xxx aluminum alloy was produced by semi-continuous casting. Macrostructure, microstructure, composition distribution and hardness distribution of composite interface were analyzed. Macrostructure shows that composite interface is planar and clean with little evidence of porosity; microstructure shows that composite interface is a kind of metallurgical bonding; composition and hardness distributions have a good corresponding relationship. At the same time, the mechanical property of composite interface was measured, the tensile strength is 71 MPa, the shearing strength is 62 MPa and the bending strength is 142.5 MPa, which can also show that composite interface is a kind of metallurgical bonding. Temperature distribution of composite interface was obtained by measuring temperatures near composite interface in 1xxx aluminum alloy.
关键词:
Composite material
J.Brnic´
,
G.Turkalj
材料科学技术（英文）
Recent engineering design as well as material processing on the optimization procedure are based and computer oriented. Finite element stress and sensitivity analysis are the most important things in such modern determination of optimal solution. According to high computer capacity finite element continuum discretization and load application independent of the coming fields become unlimited. This paper deals with the development of a new finite elements generation used in shear stress analysis caused by S.Venant’s torsional load and bending with shear. Their stiffness matrices and load vectors on the basis of their geometrical properties are derived. For justification of new finite elements application some examples are presented.
关键词:
New finite elements
,
null
,
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