A .A.Khedr
,
I.Z.Selim
,
K.M.El-Sobki and O.S.Shehata(Physical Chemistry Dept.
,
National Research Centre
,
Dokki
,
Cairo
,
Egypt)
材料科学技术（英文）
Electrochemical behaviour of stainless steel type 430 in acidic solutions of methanol, ethanol and in their binary mixtures with water (from 0 to 100% alcohol) at 25℃ has been studied. using potentiostatic poIarization technique and weight loss method. It was found that the corrosion rate of the metal was affected by the physico-chemical properties of the media such as, viscosity, state of solvation, molar volume contraction, proton availability and dielectric constant, it was demonstrated from the potentiostatic study that the active passive transition strongly depended on the concentration of the acid, and on the water content of the media.
关键词:
Materials Letters
Secondary M,C precipitation was investigated in K40S cobalt-base alloy after 100 h aging at 950 degreesC. The results showed that it was closely related to the tungsten-rich zones inherited from the as-cast condition and the degeneration of the primary M7C3 carbide. A direct element reaction, 6M + C --> M6C, in which C comes from the decomposition of the M7C3 carbides, is suggested as the mechanism of secondary M6C precipitation in K40S alloy. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
M6C precipitation;aging;M7C3 carbide;superalloy
Ying LI
材料科学技术（英文）
Oxide materials NaCo2O4 and (Na1-yMy)1.6Co2O4 (M=K, 0.05≤y≤0.35; M=Ca, Sr, 0.10≤y≤0.40) were prepared by a sol-gel method. Experimental results indicated that the Seebeck coefficient and the Power-factor of Na Co2O4 were improved by doping Ca and Sr but not by K. The Power-factor of NaCo2O4 is in its maximum, 1.68×10-4 W•m-1•K-2 and 11% bigger than that of the original one when the dopant fraction of Ca was 0.1. Doping Sr makes NaCo2O4 have the biggest Power-factor, 1.68×10-4 W•m-1•K-2 that is 50% bigger than the non-doping oxide. The experimental results indicate that suitable dopants and addition amounts could improve the thermoelectric properties of NaCo2O4 greatly.
关键词:
Thermoelectric materials
,
materials
,
Electric
,
proper
王兆伟
,
李士钊
液晶与显示
doi:10.3788/YJYXS20142903.0389
针对野外恶劣使用环境,设计了一种环境适应性强的显示控制系统.该系统采用基于DSP和S1D13305控制EL显示屏的设计方案,从软硬件两方面阐述了DSP和显示控制芯片之间的接口电路和设计方法,解决了显示控制芯片内部字库内容单一的问题,并给出了系统设置和显示控制芯片初始化程序,开发了显示驱动模块.经过实战考核和应用,该显示系统在野外恶劣环境中工作稳定,显示效果良好.该显示系统达到了预期效果.
关键词:
控制
,
DSP
,
S1D13305
,
EL显示屏
LI Guirong
,
WANG Hongming
,
DAI Qixun
,
ZHAO Yutao
,
LI Jingsheng
钢铁研究学报(英文版)
The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3containing mould fluxes were studied. The corresponding physical properties of 3791%CaO4309%SiO25%Al2O35%MgO2%Li2O7%B2O3 mould fluxes were as follows: the melting point was 909 ℃, the flowing temperature was 1 160 ℃, the viscosity and surface tension at 1 300 ℃ were 04 Pa·s and 032 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
关键词:
B2O3containing mould flux;fluoridefree flux;harmless flux;physical property
李志友
,
黄伯云
,
汤春峰
,
刘志坚
,
曲选辉
功能材料
用柠檬酸盐溶胶-凝胶工艺制取了三种β-MxV2O5氧化物Li0.3V2O5、Na0.33 V2O5和K0.25V2O5;TG和DTA试验显示干凝胶焙烧过程中出现两个吸热峰,中间有一个放热峰;XRD分析表明高温处理时Li0.3 V2O5可氧化成LiV3O8和V2O5,而Na0.33V2O5和K0.25有较好的化学稳定性;模拟Li-B合金/LiCl-KCl/β-MxV2O5(或α-V2O5)热电池500℃放电试验表明β相阴极放电较α相平稳,但初始电压峰值略有降低,β-Li0.3V2O5相因具有较α-V2O5相更通畅的Li+快速扩散通道,且通道内没有Na+或K+大离子对Li+扩散的阻碍,放电最为平稳,有效比容量最高.
关键词:
溶胶-凝胶工艺
,
β相钒青石
,
热电池
,
阴极
X.M.Min
,
Y. Daiand C.W.Nan National Key Laboratory of Advanced Technology for Materials Synthesis and Processing
,
Wuhan University ofTechnology
,
Wuhan 430070
,
China
金属学报(英文版)
Al NMRand quantum chemistry calculation have been used to study thestructureof γ Al2O3 and AlON. The NMRspectra arecharacterized bythree distinctresonance peaksat114 , 66 and 12 , corresponding to 〔AlN4〕,〔AlO4〕and 〔AlO6〕respectively. The uantum chemistrycalculationsshowqd thatthe models with vacancieslocated at octahedralsitein B block are morestablethanthose with vacancieslocated attetrahedralsitein A blockforboth of γ Al2 O3 and AlON. In AlON, nitrogen atoms preferentially replace oxygen atoms in〔AlO4〕tetrahedrons, and the model with 〔AlN4〕is morestablethan that with 〔AlO4 xNx〕(x= 1 ,2 and 3) and 〔AlO6 - yNy〕(y= 1 ,2 ,3 and 4) , which isin agreement with theexperimental analysisby NMR.
关键词:
Al2 O3 and AlON
,
null
,
null
,
null
Journal of Nanoparticle Research
Dy(2)O(3)-coated Dy nanoparticles and Al(2)O(3)-coated Dy nanocapsules, with Dy cores with the average size of 3.6 and 17.6 nm, respectively, are synthesized by arc-discharge technique. The transition from ferromagnetism to antiferromagnetism absents in the Dy nanoparticles, due to that its average core size of 3.6 nm is smaller than the helix period of Dy. The temperature of the superparamagnetism-antiferromagnetism transition in the Dy nanocapsules increases abnormally to 105 K, while the N,el temperature decreases to 150 K. The magnetic-entropy change (-a dagger S (m)) of the Dy nanoparticles rapidly increases with decreasing temperature. For Al(2)O(3)-coated Dy nanocapsules, -a dagger S (m) reaches 15.2 J kg(-1) K(-1) at 7.5 K, due to the existence of superparamagnetism, and a peak (5.2 J kg(-1) K(-1)) appears at 105 K due to the superparamgantism-antiferromagnetism transition, and -a dagger S (m) exceeds 2 J kg(-1) K(-1) in the temperature range from 7.5 to 105 K, for a field change from 1 to 5 T.
关键词:
Nanoparticles;Magnetic properties;Size effect;Rare-earth metals;films;dysprosium;carbon;gd
YUE Kexiang DONG Yuanchi East China Institute of Metallurgy
,
Ma'anshan
,
China
金属学报(英文版)
The equilibrium constants between Sr-O,Ba-O and Sr-S,Ba-S in liquid iron at 1570℃ and the interaction coefficients concerning these elements have been determined as follows: K_(Sro)=1.897×10~(-7),e_O~(Sr)=-43.8 K_(BaO)=8.204×10~(-8),e_O~(Ba)=-98.0 K_(SrS)=8.356×10~(-7),e_S~(Sr)=-3.9 K_(BaS)=4.083×10~(-7),e_S~(Ba)=-3.5
关键词:
equilibrium
,
null
,
null
,
null
,
null
Chinese Journal of Chemical Engineering
K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and BET. Their electrochemical performances were investigated by means of galvanostatic discharge and electrochemical impedance spectroscopy (EIS). The results of physical characterization showed that the two samples have similar structural features, but their surface morphologies and oriented growth of the crystals are different, which results in smaller specific surface area and lower solubility of the ex-situ electrosynthesized K2FeO4 sample. The results of discharge experiments indicated that the ex-situ electrosythesized K2FeO4 electrode has much larger discharge capacity and lower electrode polarization than the in-situ electrosynthesized K2FeO4 electrode. It was found from the results of EIS that lower electrochemical polarization might be responsible for the improvement on the discharge performance of the ex-situ electrosynthesized K2FeO4 electrode.
关键词:
K2FeO4;electrosynthesis;discharge performance;electrochemical;impedance spectroscopy (EIS);super-iron battery;fe(vi) ferrate;fuel-cell;electrolyte;cathodes
