G.B.Liu
,
W.L.Wang
,
C.G.Hu
,
K.J.Liao
,
Q.Feng
,
L.H.Feng
金属学报(英文版)
The effect of annealing treatment on the structure of CdS films was investigated.The cadmium sulfide thin films were prepared by chemical bath deposition, and were annealed at nitrogen atmosphere at different temperatures. The films were charac-terized by SEM and XPS (X-ray photoelectron spectroscopy). X-ray photoelectron spectroscopy was used to examine the chemical states on the CdS films surface. It was found that thermal annealing could produce large grains of CdS thin films, remove the air contamination and reduce the oxygen content on the CdS films surface. Therefore,the CdS films changed more uniform and smoother surface after thermal annealing.
关键词:
XPS
,
null
,
null
王利平
,
王彦冬
,
孔丽丽
,
李玲玲
高分子材料科学与工程
以空心球表面负载的叔丁基过氧化氢为引发剂,通过反向原子转移自由基聚合制备了空心球-聚甲基丙烯酸甲酯杂化材料,以此为引发剂,以含有甲基丙烯酸甲酯的铽配合物为第二单体,通过原子转移自由基聚合制备了空心球-g-PMMA-b-Tb杂化材料,并用FT-IR、GPC、TG和荧光光谱等对产物进行了测试与分析.结果表明,PMMA在空心球表面的接枝率约为8%;溶液中形成的PMMA的Mw为28800,分子量分布指数(PDI)为1.2;杂化材料在489 nm,545 nm,583 nm,621 nm左右出现了四组发射峰,分属于Tb(3+)的5D4→7F6、5D4→7F5、5D4→7F4和5D4→7F3跃迁;铽配合物已接枝到空心球表面,生成了具有发光性能的杂化材料.
关键词:
空心球
,
反向原子转移自由基聚合
,
铽配合物
,
光功能
原博
,
魏江霞
,
胡天娇
,
姚海波
,
蒋振华
,
方志薇
,
楚增勇
催化学报
doi:10.1016/S1872-2067(15)60844-0
在空气中直接加热三聚氰胺和氧化石墨烯(GO)的混合物制备了g-C3N4/rGO杂化催化剂.实验结果表明，混合物中的g-C3N4保留了石墨型氮化碳原始的特征结构， g-C3N4和还原的氧化石墨烯(rGO)之间的异质结主要通过π-π作用构筑.当原料中三聚氰胺/GO的质量比是800/1时，所得催化剂对罗丹明B的催化作用最强，其一阶动力学常数是纯g-C3N4的2.6倍.这种强化作用主要是由于rGO促进了光生电子-空穴对的分离.此外， g-C3N4/rGO还表现出显著的pH值敏感特性，催化降解速率随pH的降低而增加.当pH =1.98时，其一阶动力学常数是纯g-C3N4的8.6倍.这是由于酸性条件下质子(H+)消耗掉光生电子，促进了空穴对罗丹明B的氧化作用，其中rGO充当了一个快速的光生电子转移平台.
关键词:
氮化碳
,
氧化石墨烯
,
光催化
,
pH敏感性
,
罗丹明B降解
田磊
,
敖青
,
刘玉爱
,
李胜利
材料热处理学报
通过控制热处理参数在G55SiMoV钢中获得了不同贝氏体含量的马氏体/贝氏体复相组织,研究了贝氏体含量对其韧性和回火脆性的影响.结果表明:随等温时间延长贝氏体含量增加,等温淬火5 min、15 min、30 min、60 min可分别获得17％、27％、29％、31％的贝氏体.当贝氏体量较多(大于27％)时,马氏体对贝氏体的应变强化效果降低,韧性提高更加显著.300℃以下回火时组织和硬度基本不变;300℃回火时存在回火脆性,该马氏体/贝氏体复合组织钢的回火脆性温度区间几乎不受贝氏体量的影响,但增加贝氏体量可以提高残留奥氏体稳定性,使韧性降幅减小.
关键词:
马氏体/贝氏体复相组织
,
贝氏体含量
,
回火脆性
,
残留奥氏体稳定性
,
韧性
吴崇珍
,
崔喆
,
赵清香
,
刘民英
,
付鹏
高分子材料科学与工程
通过连续原子转移自由基聚合(ATRP)技术,首次合成出3个系列以β-环糊精(β-CD)为核心、内嵌段为刚性链聚苯乙烯(PS)、外嵌段为聚丙烯酸(PAA)的21臂两亲性星形嵌段共聚物β-CD-g-21 (PS-b-PAA).并利用核磁氢谱、红外光谱、凝胶色谱对所得聚合物的化学结构、相对分子质量及其分布进行了表征.证实β-CD的21个羟基均发生了聚合反应,所得的共聚物相对分子质量分布窄,均在1.35以下.通过水解嵌段聚合物大分子链和β-CD之间的酯键,计算出PS-b-PAA的相对分子质量分别为3100、4200、5800.实验结果表明,合成出的星形嵌段聚合物结构明确,相对分子质量分布可控.
关键词:
原子转移自由基聚合
,
β环糊精
,
两亲性
,
星形嵌段共聚物
Physica B-Condensed Matter
The perturbation formula of g factor for 3d(7) ion in cubic octahedral crystals has been obtained from a cluster approach. In the formula, the parameters related to the configuration interaction and the covalency reduction effect can be obtained from the optical spectra of the crystal under study and so no adjustable parameters are applied. From the formula, the g factors for Co2+ in fluoroperovskites LiBaF3, KMBF3, KZnF3 and CsCdF3 are calculated. The calculated results are in agreement with the observed values. The g factor following the order of LiBaF3 : Co2+ < KMgF3 : Co2+ < KZnF3: Co2+ < CsCdF3 : Co2+ is also explained. (C) 2000 Elsevier Science B.V. All rights reserved.
关键词:
electron paramagnetic resonance;crystal- and ligand-field theory;Co2+;LiBaF3;KMgF3;KZnF3;CsCdF3;perovskite;transition;impurities;crystals
Journal of Alloys and Compounds
The EPR g factors g(x), g(y) and g(z) and the local structures for the orthorhombic Nd3+ centers in YAG, YGG and LuGG garnets are studied by using the perturbation formulas of the g factors for a 43 ion in orthorhombic symmetry. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various energy levels are considered. Based on the analyses of the g factors, we find that the polar angles theta'(j) of the impurity-ligand bonds related to the Z-axis of the crystals in these Nd3+ centers are smaller than the host angles theta(j) in pure crystals, whereas the azimuthal angles phi'(j) related to the X-axis in the impurity centers are larger than the corresponding phi(j) in the hosts. The calculated g factors, particularly their anisotropies Delta g [= g(z) - (g(x) + g(y))/2] and delta g (= g(x) - g(y)) for Nd3+ in the gamets based on the above local angles show reasonable agreement with the observed values. (c) 2004 Elsevier B.V. All rights reserved.
关键词:
electron paramagnetic resonance (EPR);defect structure;crystal-field;and spin hamiltonians;Nd3+;garnets;crystal-field;substituted garnets;superposition-model;magnetic-properties;neodymium;laser;parameters;calcium;cerium;ion
