Qian LI
,
Qin LIN
,
Lijun JIANG
,
Guozhi ZHOU
,
Feng ZHAN
,
Qiang ZHENG
材料科学技术（英）
A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigated by means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showed that the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis without any activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp (0.1 MPa)=-3026/T+5.814 (523 K≤T ≤623 K) for hydriding and lgp (0.1 MPa)=-3613/T+6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1-α)]3/2 = kt and the apparent activation energy for the nucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31 kJ/(mol·H2) and 59.9±2.99 kJ/(mol·H2) respectively.
关键词:
Hydriding combustion
,
null
,
null
,
null
刘欣艳
,
赵煜娟
,
夏定国
功能材料
LiNi0.8Co0.2O2是锂离子电池界公认的最有希望取代商业化正极材料LiCoO2的新型正极材料之一.本文所研究的复合正极材料LiNi0.8Co0.2O2是由细小的晶粒构成的球形颗粒,单一相,属于R3m空间群.对复合材料LiNi0.8Co0.2O2的Co-K和Ni-K的XANES分析可知,在600～850℃范围温度对于钴元素的影响不明显,而对于镍元素的影响比较显著,随着Ni-K边位置向高能量移动LiNi0.8Co0.2O2正极材料的放电容量升高.复合材料LiNi0.8Co0.2O2和LiNiO2的Ni-K边XANES相似,表明少量钴的引入对晶体结构的改变不是太多,但是峰的强度较高和峰的位置向高能量移动,表明钴Co对Ni的局域结构进行了调制.
关键词:
LiNi0.8Co0.2O2
,
XANES
,
正极材料
,
局域结构
席俊华
,
季振国
,
刘坤
,
王超
,
杜鹃
无机材料学报
doi:10.3724/SP.J.1077.2006.01506
利用溶胶-凝胶法结合高温热处理在硅衬底上制备了掺Mn硅酸锌薄膜, 用XRD、SEM、UV-Vis吸收谱和PL谱测试了样品的结晶性能与光学性能, 并分析了热处理温度对掺Mn硅酸锌薄膜的结晶性能和光学性能的影响. 实验结果发现, ZnO的适量存在对掺Mn薄膜的发光有增强作用. 进一步的分析认为, 这一现象的机理可由G.G. Qin提出的量子约束-发光中心 (QCLC) 模型进行解释, ZnO中受激发的电子和空穴通过隧穿效应到达硅酸锌基体中复合发光, 从而增强发光强度.
关键词:
硅酸锌
,
ZnO
,
photoluminescence
,
quantum confinement-luminescence center
Materials Research Bulletin
Through analysis of the latest experimental results reported in the literature and obtained in our laboratory, we have extended our previous quantum confinement/luminescence center model for the photoluminescence mechanism of porous Si and of nanometer-silicon-particle-embedded Si oxide films (G.G. Qin and Y.Q. Jia, Solid State Commun. 86, 559 (1993)). We consider that there are three main types of competitive photoexcitation/photoemission processes and that the process in which photoexcitation occurs in the nanometer silicon particles (NSPs) while photoemission occurs in the luminescence centers (LCs) in the SiOx layers very close to the NSPs is usually the major one. We discuss under what conditions the other two types of processes will dominate. We believe that the extended quantum confinement/luminescence center model is a physical model that is suitable for the photoluminescence from silicon oxide films embedded with NSPs or nanometer Ge particles (NGPs), as well as from oxidized porous Si. (C) 1999 Elsevier Science Ltd.
关键词:
oxides;luminescence;defects;blue-light emission;visible luminescence;optical-properties;nanocrystals;mechanism;dependence;sio2-films;absorption;spectra;defects
Physical Review B
In response to the comment by Wang and Qin, we have rewritten our equation (22) following the coordinate system of Dina, et al. [J. Wuhan Univ. (Nature Science Edition) 3, 23 (1992)]. According to the thermodynamic stability condition and the experiment of Capitan et al., we have chosen the new parameters of the phason elastic constants. Based on this, we have recalculated the coefficients of the expressions on the vibrational denty of states and the specific heat of the icosahedral Al-Nin-Pd quasicrystal. Our results are still in agreement with the experimental data measured by Walti et al. [Phys. Rev. B 57, 10 504 (1998)]. It demonstrates that our method is useful for dealing with the low-temperature vibrational excitation of icosahedral quasicrystals.
关键词:
quasi-crystals;diffuse-scattering
吴运军
,
张武
,
马怀柱
稀土
doi:10.3969/j.issn.1004-0277.2003.06.004
采用Schlenk技术,在干燥纯氩气保护下,用无水三氯化稀土LnCl3与2-苯基茚以1∶2的摩尔比在THF中反应,得到8种新配合物:(2-ph-Ind)2LnCl (A)[Ln=La(1), Pr(2), Nd(3), Sm(4), Gd(5), Dy(6), Yb(7), Y(8)].再用(A)和LiN(TMS)2在THF中反应,得到两种新的二(2-苯基茚)稀土有机配合物:(2-ph-Ind)2LnN(TMS)2 (B)[Ln=Y(1), Sm(2)].所有配合物都经元素分析、红外和质谱鉴定.配合物(B)在甲基丙烯酸甲酯(MMA)的聚合反应中显示出一定的活性.
关键词:
稀土合成
,
配合物
,
聚合
,
2-苯基茚
贺慧
,
程璇
,
张颖
,
杨勇
功能材料
利用溶胶-凝胶预处理固相方法合成了锂离子电池正极材料LiM0.9Ti0.1O2(M=Ni,Co),通过XRD对合成的材料进行结构分析,并将其组装成电池进行了电化学测试,对两种材料LiN0.9Ti0.1和LiCo0.9Ti0.1进行了比较.结果发现,LiCo0.9Ti0.1O2的结构和性能要好于LiNi0.9Ti0.1O2,根据实验结果对其原因进行了初步的分析.
关键词:
锂离子电池
,
正极材料
,
电化学性能
席俊华
,
季振国
,
刘坤
,
王超
,
杜鹃
无机材料学报
doi:10.3321/j.issn:1000-324X.2006.06.038
利用溶胶-凝胶法结合高温热处理在硅衬底上制备了掺Mn硅酸锌薄膜,用XRD、SEM、UV-Vis吸收谱和PL谱测试了样品的结晶性能与光学性能,并分析了热处理温度对掺Mn硅酸锌薄膜的结晶性能和光学性能的影响.实验结果发现,ZnO的适量存在对掺Mn薄膜的发光有增强作用.进一步的分析认为,这一现象的机理可由G.G.Qin提出的量子约束-发光中心(QCLC)模型进行解释,ZnO中受激发的电子和空穴通过隧穿效应到达硅酸锌基体中复合发光,从而增强发光强度.
关键词:
硅酸锌
,
氧化锌
,
光致发光
,
量子约束-发光中心
刘守平
,
周上祺
,
王佳眉
,
任勤
腐蚀科学与防护技术
用金相显微镜、扫描电镜、X射线衍射仪和X射线能谱仪对天然气井油管悬挂器腐蚀失效进行了检测分析，并对天然气井油管悬挂器用35CrMo钢进行了盐雾试验，结果表明，天然气中的水和CO2是引起腐蚀的主要介质，腐蚀产物主要是FeCO3，高速天然气冲刷和钢中的非金属夹杂加剧了腐蚀的速度.
CORROSION FAILURE ANALYSIS OF AN OIL TUBE USED IN NATURAL GAS WELL
LIU Shou-ping,ZHOU Shang-qi,WANG Jia-mei,REN Qin
Chongqing University
A failed oil tube used in natural gas well was examined by optical microscope,scanning electron microscope ,X-ray diffractometer and X-ray spectrometer.Corrosion behavior of 35CrMo steel samples of the oil tube were investigated by means of salt spray tests in the laboratory.The results show that CO2 and H2O are primary factors in the corrosion of oil tube.The corrosion product is FeCO3,non-metallic inclusions in the steel and erosion of natural gas fluid played an important role in accelerating the corrosion.
oil tube;
natural gas well；
35CrMo steel；
failure analysis；
corrosion
关键词:
悬挂器
,
null
,
null
,
null
常照荣
,
郁旭
,
汤宏伟
,
王超楠
,
魏文强
功能材料
利用低共熔组成的0.38LiOH " H20-0.62LiN03混合锂盐体系与共沉淀合成的前躯体Ni1/3Co1/3Al1/3 (OH)2简单混合,经三阶段温度烧结制备出锂离子电池正极材料LiNi1/3 CO1/3 A11/3 O2,该法工艺简单,成本低,无需研磨即可以使物料在低共熔点温度上达到均匀混合的目的.经X粉末射线衍射(XRD)分析表明,合成的LiNili 1/3 CO1/3 Al1/3 O2具有典型的a-NaFeO2六方层状结构,其特征衍射峰I(003) /I(104)的峰强比值高达1.73.电性能测试表明,在5 5 0C,电压范围为2.8-4.3V,充放电倍率为0.2C的条件下,首次充放电比容量为156.4mAh/g,30次循环后容量保持率为94.1%,l和2C倍率放电容童仍可达到143.2和127.9mAh/g,其电性能均优于常温下的性能.
关键词:
锂离子电池
,
低共熔盐
,
掺杂
,
LiNi1/3CO1/3Al1/3O2
