喻发全
,
刘艳萍
,
黄世英
,
姚树人
高分子材料科学与工程
采用McGiniss改良膨胀计与SW-1型微位移测量仪,测定了丙烯酸(AA)-丙烯腈(AN)感光共聚合速率;用102-G气相层析仪及1106型元素分析仪对AA-AN感光聚合体系的单体浓度比及共聚物链节比进行了定量分析,按假定的反应机理计算了单体的竞聚率,在40 ℃时的结果为rAA=2.85,rAN=0.038.
关键词:
丙烯腈
,
丙烯酸
,
紫外光
,
感光共聚
,
动力学
,
竞聚率
陈厚
,
刘军深
,
曲荣君
,
纪春暖
,
王成国
,
蔡华甦
高分子材料科学与工程
采用Kelen-Tudos方法, 测定了丙烯腈(AN)与丙烯酸(AA)共聚合反应体系中单体竞聚率,探讨了不同反应体系对单体竞聚率的影响.结果表明,在水相悬浮聚合体系中,当转化率小于20%时,两单体的竞聚率同DMSO均相溶液聚合结果相近;随转化率的增加,AN竞聚率增加,AA竞聚率减小,当转化率超过50%后,两单体竞聚率变化不明显.在H2O/DMSO混合溶剂沉淀聚合中,当水含量超过80%后,两单体竞聚率向水相悬浮聚合结果靠近.随溶剂极性增大,rAN与rAA值均减小.
关键词:
共聚反应
,
动力学
,
竞聚率
羊羽翔
,
付建新
,
宋卫东
黄金
doi:10.11792/hj20140808
矿山在充填管道布置方案中参数的选取往往通过经验公式估算，而目前尚无精确解的计算方法。但参数的选取恰当与否直接影响到矿山充填系统的效率以及使用寿命，因此参数选取的精确化便显得尤为重要。以石人沟铁矿的充填系统为工程背景，应用ANSYS分析软件中的FLOT-RAN CFD模块建立管道模型，分析了管道系统采用不同充填倍线时流速与压力的关系，并据此对充填倍线的理想值进行了分析计算，最终得出充填倍线为3．5，符合经验值的取值范围，对矿山充填管道布置方案有一定借鉴意义。
关键词:
FLOTRAN CFD模块
,
充填倍线
,
管道模型
,
FLUD141单元
,
方案优化
Journal of Materials Processing Technology
This paper has studied systematically the preparation technology and its effects on the structure and amorphous forming region (AFR), and theoretical description of the AFR for electroless Ni-P alloys. It has been found that the deposition rates increase and approach a maximum value and then decrease with the increase in the concentration of nickel chloride, sodium hypophosphite and pH value, respectively. However, the deposition rates decrease with the increase in sodium citrate. The AFR is P > 9-10 at.% in the range of concentration of nickel chloride studied. In the ran-e of concentration of sodium hypophosphite studied, there was no crystalline structure observed. The AFR calculated theoretically using the Miedema model was in good agreement with the experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.
关键词:
electroless Ni-P alloys;preparation technology;structure;amorphous;forming region;Miedema model;formation enthalpies;nickel deposition;mechanism
陈厚
,
王成国
,
张旺玺
,
蔡华甦
高分子材料科学与工程
利用Kelen-Tudos方法测算丙烯腈(AN)与N-乙烯基吡咯烷酮(NVP)自由基共聚合单体竞聚率,研究了不同反应体系对单体竞聚率的影响.结果发现:在水相悬浮聚合体系中,转化率小于18%时,两单体的竞聚率同DMSO均相溶液聚合结果相近;转化率较大时,同溶液聚合结果偏差较大.H2O/DMSO混合溶剂悬浮聚合时,当水含量超过60%(质量比)后,单体竞聚率向水相悬浮聚合结果靠近.溶剂的极性增大,rAN与rNVP值均减小.随反应温度升高,共聚反应向理想共聚方向进行.
关键词:
丙烯腈
,
N-乙烯基吡咯烷酮
,
竞聚率
宋雪
,
张国俊
,
纪树兰
,
王乃鑫
,
刘忠洲
膜科学与技术
doi:10.3969/j.issn.1007-8924.2009.05.001
采用单内皮层中空纤维RAN超滤膜作为基膜,通过动态负压层-层静电吸附法在内皮层上组装聚电解质派对PEI/PAA,制得单内皮层中空纤维聚离子复合膜.研究了支撑层、派对数、负压侧真空度、循环流速等动态组装条件对复合膜渗透汽化性能的影响,考察了复合膜对不同醇/水体系的渗透汽化分离性能.结果表明,当进料液为50℃的质量分数95%异丁醇/水体系时,分离因子达23 731,渗透通量为360.5 g/(m2·h),显示了较好的渗透汽化性能.
关键词:
中空纤维
,
聚离子复合膜
,
渗透汽化
,
动态负压LBL技术
WANG Wencai CHEN Yu Peking University
,
Beijing
,
China Associate Professor
,
Dept.of Physics
,
Peking University Beijing
,
China
金属学报(英文版)
The short-range order structures of Fe_xGe_(1-x) amorphous thin films,(x=8.7,19.1 and 28.5%)have been studied by means of X-ray absorption spectrum.The nearest neighbors around a Ge or an Fe atom are constituted by two coordinate sub-shells with a very short dis- tance,In two films with lower Fe content,structural parameters of the nearest neighbors around a Ge atom are very near to that in amorphous germanium,and the positions of Fe at- oms are randomly substitutional.But when x=28.5%,some great changes occur on the short-range order structure of a-Fe_xGe_(1-x) film:its structure deviates from continuous ran- dora network and tends toward dense random packing of atoms.Meanwhile,there is a strong- er interaction between near neighboring Fe-Ge atoms in a-Fe_xGe_(1-x) films.
关键词:
Fe-Ge amorphous thin film
,
null
,
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