Rangsu LIU
,
Jiyong LI
,
K.J.Dong
,
R.P.Zou
,
A.B.Yu
材料科学技术（英文）
A molecular dynamics simulation of rapid cooling process has been performed for a large-scale system consisting of 400,000 Al atoms with a supercomputer. To study the formation and evolution mechanisms of nano-clusters in solidification, the so-called cluster-type index method has been applied to describe the structural configurations of the basic small clusters and combined larger clusters obtained from the simulation. The results show that relatively large nano-clusters are formed from small and medium sized clusters through continuous mutual competitions of annexation and evolution of small clusters in a seesaw manner, giving a structure different from the multi-shell structure where an atom acts as the center of a cluster and the surrounding atoms are arranged according to a certain rule.
关键词:
Liquid metal
,
null
,
null
朱海燕
,
王雪兆
,
尹家兴
,
李丁丁
,
魏永豪
,
陈志军
高分子材料科学与工程
采用原位活性聚合法在玻璃表面接枝聚苯乙烯与聚4-乙烯吡啶无规共聚物（PS-r-P4-VP）＂刷子＂,并对其进行表征。X射线光电子能谱（XPS）结果表明,玻璃表面接枝共聚物后,Si（1s/2p）、O（1s）的吸收峰强度降低,C（1s）吸收峰强度增强并出现了N（1s）（吡啶环）的特征吸收峰;椭圆偏振仪测试结果表明,接枝PS-r-P4-VP的厚度随聚合时间延长而增加,表面均方粗糙度则减小;原子力显微镜（AFM）观察结果表明,随着St配比的增加,玻璃表面聚合物＂刷子＂粗糙度降低;红外光谱（FT-IR）表明,玻璃表面的聚合物为PS-r-P4-VP;透光率测试表明,在玻璃表面接枝PS-r-P4-VP并不影响玻璃的透光率;接触角测试结果表明,接枝共聚物的玻璃表面接触角随着St比例的增加而显著增大。
关键词:
原位接枝
,
聚合物“刷子”
,
聚苯乙烯与聚4-乙烯吡啶无规共聚物
陶明
,
熊伟
,
陈华
,
李贤均
催化学报
合成了(R,R)-1,2-二苯基乙二胺((R,R)-DPEN)、钌和三苯基膦的三元配合物RuCl2[P(C6H5)3]2-(R,R)-DPEN,并将其用于萘乙酮的不对称加氢反应.考察了碱/催化剂的摩尔比、反应温度和氢气压力等对催化活性和对映选择性的影响.结果表明,多种因素对反应的转化率和对映选择性均有影响.在萘乙酮:(CH3)3COK:催化剂摩尔比为50 000:450:1,氢气压力为4 MPa,反应温度为25℃的条件下,反应16 h时,萘乙酮生成α-萘乙醇的产率和对映选择性分别达到了100%和83%.
关键词:
钌膦配合物
,
手性二胺
,
萘乙酮
,
不对称催化加氢
,
α-萘乙醇
,
对映选择性
周训飞
,
赵小明
,
郭智恺
,
刘志刚
工程热物理学报
应用P-R方程编制了容积绝热指数与温度绝热指数的计算程序,利用该程序计算了HFC-161,HC-290,HC-600a的绝热指数,绘出了三种制冷剂的容积绝热指数与温度绝热指数随对比压力与对比温度变化的图线,并加以对比与分析。结果表明,HC-600a的两种绝热指数值都较小,在压缩机进出口条件一致的状况下,较适于作为替代制冷剂。
关键词:
替代制冷剂
,
绝热指数
,
P-R方程
陈志军
,
魏永豪
,
朱海燕
,
杨清香
高分子材料科学与工程
用乳液聚合的方法合成了交联P（St-r-AA）包覆的Fe3O4粒子,研究了该类粒子对Cu2＋离子的吸附性能。透射电镜（TEM）表明,交联的P（St-r-AA）包覆的Fe3O4磁性粒子粒径约100 nm;X射线衍射（XRD）分析表明,磁性粒子中磁性物质为尖晶石结构的Fe3O4;红外光谱（FT-IR）表明,Fe3O4表面的聚合物含有苯环和羧基;热重（TG）分析表明,粒子中磁性粒子的含量为31%;P（St-r-AA）包覆的Fe3O4磁性粒子具有超顺磁性,比饱和磁化强度为0.822 A.m2/kg;UV-vis表明磁性粒子能够有效吸附溶液中的Cu2＋离子。
关键词:
交联P(St-r-AA)
,
磁性纳米粒子
,
Cu2+离子吸附
武秀兰
,
任强
,
王芬
硅酸盐通报
doi:10.3969/j.issn.1001-1625.2006.01.008
在普通石灰碱釉的基础上引入骨粉和滑石,形成R2O-RO-Al2O3-SiO2-P2O5系统釉料,通过调整釉料的化学组成获得分相/析晶乳浊釉.利用XRD,SEM,EDS等测试技术,研究了SiO2与P2O5和SiO2与MgO的摩尔比与釉层显微结构的关系,分析了乳浊粒子(玻璃液滴和微晶)的形成机理.
关键词:
乳浊釉
,
分相
,
析晶
,
机理
Communications in Theoretical Physics
The unified theoretical calculation of thermal shifts (TS) of R-1 and R-2 lines and thermal broadenings (TB) of R, R' and B lines for ruby was carried out for the first time. The calculated results are in very good agreement with a great number of experimental data. Especially by using quantum theory and taking into account all the admixtures of wavefunctions within d(3) electronic configuration, all the Gamma M in electron-phonon interaction (EPI), the electronic energy spectrum and lattice-vibration Spectrum, the very important contributions to TS and TB from single-phonon direct process were theoretically calculated in detail. The microscopic essentials of various contributions are revealed, and the mistakes in previous work are remedied.
关键词:
diamond anvil cell;pressure measurement;spectroscopy;temperatures
陈建新
,
胡芃
,
陈则韶
,
江斌
工程热物理学报
基于制冷剂物性计算软件NIST REFPROP 7.0及R125/R600a气液相平衡实验数据,使用MBWR状态方程结合Lemmon-Jacobsen混合物模型,对R125/R600a(50/50 mass%)混合替代工质的热力学性质进行了计算,并制作给出了其压焓图(p-h)、温熵图(T-s)和比定压热容图(c<,p>-T)及饱和性质表.最后理论计算分析了其空调制冷工况的性能,结果表明该混合工质具有与R22相当的压缩比和COP值,比R22较低的排气温度和较高的单位质量制冷量.
关键词:
热力学性质
,
R125/R600a
,
制冷替代工质
Journal of Magnetism and Magnetic Materials
The temperature dependence of the magnetocrystalline anisotropy field (mu-0H(a)) of R2Fe14B(1-y)C(y) and Nd2Fe12Co2B(1-y)C(y) (R = Nd, Pr; y = 0, 0.5) compounds has been determined by applying the SPD (singular point detection) technique in a high pulse magnetometer in the temperature range of 300-600 K. To determine the Curie temperature (T(c)) of the compounds, the ac initial susceptibility measurement was employed. It was found that the influences of carbon substituting for boron and cobalt substituting for iron on the Curie temperature are independent of each other and the latter has been understood as the case where all 2p electrons which transferred from carbon to 3d bands localize around Fe. The effect of crystal electric field acting on the rare earth site is dominant at temperatures below 400 K in R2Fe14B (R = Nd, Pr) compounds. The substitution of small amounts of cobalt for Fe does not affect the crystal electric field acting on the rare earth site very much.
关键词:
Communications in Theoretical Physics
On the basis of the unified calculation of the thermal shifts of R-1 line, R-2 line and ground-state-splitting as well as the thermal broadenings of R, R' and B line-groups for ruby, by taking into account all the levels and admixtures of wavefunctions within d(3) electronic configuration and all the GammaM in electron-phonon interaction, the transition probabilities of direct and Raman processes have theoretically been calculated. The thermal broadenings, of R, R' and B line-groups have successfully been interpreted in terms of the direct and Raman processes of acoustic phonons. The theoretically predicted transition probabilities are in good agreement with the experimental ones.
关键词:
crystal fields;electron-phonon interaction;thermal broadening;transition probability;direct and Raman processes;shifts
