H.Adelkhani
,
M.Ghaemi
,
S.M.Jafari
材料科学技术（英）
Pulse current technique was applied for the preparation of novel electroactive manganese dioxide and possible influences of different electrokinetic phenomena on material characteristics were discussed. The characterizations of pulse deposited sample (pcMD) were carried out by different techniques: Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, Raman spectroscopy, and atomic force microscopy (AFM). SEM image revealed that pulse current could improve the current distribution. This was confirmed by AFM images showing a decrease in surface roughness of pcMDs in comparison to amorphous samples, which were deposited by direct current (dcMD). Higher distortion of MnO6 octahedral environment of dcMD was detected by FTIR and Raman spectroscopy. Cyclic voltammetric (CV) measurements showed a generally higher energy level drained from the second electron discharge of pcMD. This is mainly attributed to a higher surface area and a lower diffusion pass of electrons and protons arisen via a rather unique nanostructural arrangement of pcMD grains. Results indicate a higher surface area available for the non homogenous second electron discharge of pcMD grains.
关键词:
Manganese dioxide
,
null
,
null
,
null
FANG Zheng CHEN Xinmin(H.M.Chen) Central South University of Technology
,
Changsha
,
China FANG Zheng
,
Associate Professor
,
Department of Chemistry
,
Central South University of Technology
,
Changsha
,
China
金属学报(英文版)
By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a particular case of it.Some of the variables affecting equilibrium atmosphere when trace oxygen is present and optimum preparation of the gas mixtures to min- imize errors have been discussed.The reliability of some of previous equilibrium experiments under the oxygen potentials controlled by H_2O-H_2 or H_2O-H_2-inerts gas mixtures has also been criticized.
关键词:
gas equilibration method
,
null
,
null
,
null
Applied Physics Letters
ZnCoO:H nanocrystals are weak ferromagnetic at room temperature with a small coercivity and a small remanence, whereas ZnCoO nanocrystals are paramagnetic. The thermal irreversibility of zero-field cooling and field cooling magnetizations of ZnCoO:H nanocrystals corresponds to the existence of superparamagnetism due to the nanosize effect. X-ray photoelectron spectra show the incorporation of Co(2+) ions inside the ZnO lattice without changing the wurtzite structure. Our data suggest that hydrogen can induce ferromagnetism in ZnCoO and that ferromagnetic ZnCoO:H crystals with small particle size can show the superparamagnetism. (C) 2008 American Institute of Physics.
关键词:
magnetic semiconductors;zno;hydrogen;cobalt
王硕明
,
丁志军
,
于恒
,
张彩军
钢铁钒钛
研究了某H型钢厂采用半敞开方式浇注的H型钢腹板裂纹产生的原因.在该厂选取了26块有代表性裂纹的试样进行了细致的研究,研究认为:H型钢腹板裂纹主要是由钢中夹杂物因素造成,通过对钢中T[O]的研究发现,中间包T[O]量平均为94×10-6,铸坯中T[O]平均为60.8×10-6,同时对比1流铸坯和2流铸坯的T[O]量变化可以发现,中间包流场分布不合理.对该厂现有的中间包进行FLUENT模拟后发现,中间包稳流器矮坝较低,不能完全消除短路流,尤其在浇注后期,矮坝损耗殆尽,基本不起作用,短路流严重,应加以优化.
关键词:
H型钢
,
裂纹
,
夹杂物
,
数学模拟
徐峰
,
何彩红
,
徐勇
钢铁研究
简述了国内H型钢的发展现状,通过列举国内典型H型钢生产线,介绍分析了轧制H型钢的1-3-1、1-3和连轧三种工艺布置,以及目前轧制H型钢的X-X和X-H两种方法.根据目前国内生产状况,提出了H型钢技术改进的几项措施.
关键词:
H型钢
,
生产工艺
,
万能轧机
X.F.Rong and Z.Y.Qin College of Mechanical Engineering
,
Taiyuan University of Technology
,
Taiyuan 030024
,
China
金属学报(英文版)
In this paper, a deposition feature of a SiC:H films deposited by a RF sputtering system and a effect on the hardness of the films with various deposition conditions are investigated, and the effects of the silicon on a C:H are studied. It follows from the results that the properties of hardness can be changed with the depositing conditions. An increase of silane in the gas phase allows to deposit a SiC:H having tetrahedral structure. The sets of deposition conditions by which the different types of a SiC:H films can be deposited are obtained.
关键词:
a SiC:H film
,
null
,
null
刘英瑞
钢铁
简述了热轧H型钢的用途,热轧H型钢与其他型钢(工字钢)在生产工艺上的不同要求,介绍了莱钢热轧H型钢(中型)生产线的工艺流程、主要设备、关键技术,以及中型型钢产品大纲中的20个规格的热轧H型钢的开发研制工艺技术要点、存在的问题和采取的措施.
关键词:
万能轧机
,
H型钢
,
研制开发
贾玉萍
,
吴迪
,
郭娟
,
赵宪明
,
王培文
钢铁
针对H型钢轧制中的一些问题,设计了H型钢在线控冷装置.此装置采用气雾冷却方式,着重对H型钢R部进行快速冷却,冷速达100℃/s以上.试验结果表明,产品表面状态改善,晶粒细化,屈服强度和抗拉强度均提高21 MPa以上且断面性能均匀.轧件上冷床温度降低,生产效率提高,年产量达到预定产能的2倍以上且节省原冷床上风机的消耗.
关键词:
H型钢
,
型钢轧制
,
气雾冷却
,
控制冷却
