Phase Structures of Nascent Polyethylene Powder Studied by Wideline Proton NMR

The wideline proton NMR spectra of polyethylene powder samples were analyzed in terms of contributions from three components： （1） a rigid part with immobile chains, （2） a soft region with liquid-like character which produces a Lorentzian contribution to the spectrum, and （3） an intermediate region in which the rotation of methylene groups about C-C bonds is partially hindered. The relative mass fractions as well as chain mobilities varied greatly among samples produced by different polymerization techniques. The NMR crystallinity agreed well with that estimated by WAXD and was much higher than DSC crystallinity, indicating an inclusion of the contribution from a crystalline-amorphous interphase. The crystalline defects in the rigid part could be significantly affected by processing parameters when employing the same type of polymerization technique. The intermediate region in the NMR spectra was analyzed according to the comparison between bimodal high density polyethylene and corresponding linear unimodal one. It was found that the mass fraction of the NMR interphase could be an indication of the percentage of tie molecules between crystalline lamellae and thus may significantly affect the mechanical properties of polymeric material.     

Synthesis and Crystal Structure of （Et4N）3[{V（o—C6H4OS）3}2Na]

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ（Ｅｔ_４Ｎ）_３［｛Ｖ（ｏ－Ｃ_６Ｈ_４ＯＳ）_３｝_２Ｎａ］￥ＷｅｎＴｉｎｇ－Ｂｉｎ；ＸｕＹｏｎｇ－Ｊｉｎ；ＳｈｉＪｉ－Ｃｈｅｎｇ；ＤｅｎｇＹｕ－Ｈｅｎｇ；ＣｈｅｎＣｈａｎｇ－Ｎｅｎｇ；Ｌｉｕ...     

近年物理化学滴定进展

评述了近五年国内外物理化学滴定（用作图确定终点）的新进展，内容包括：（１）光学滴定（含光度、荧光、磷光、化学发光滴定）；（２）电滴定（含电位、电导、电流、库仑滴定）；（３）量热滴定。每类滴定均再按滴定用介质分为水介质和非水介质滴定，按滴定反应分为酸－碱、氧化－还原、络合、沉淀滴定，按滴定方式分为直接滴定、代滴、回滴。引用文献１０６篇。     

Pitzer-Simonson理论和Pitzer-Simonson-Clegg理论在离子液体PMIBF4水溶液中的应用

在278.15～343.15 K温度范围内, 测定了在浓度范围从摩尔分数0.09的四氟硼酸-1-甲基-3-戊基咪唑(PMIBF₄)离子液体水溶液到纯离子液体的密度, 计算了离子液体PMIBF₄水溶液的表观摩尔体积^fV, 讨论了Pitzer-Simonson (PS) 理论和Pitzer-Simonson-Clegg (PSC)理论的适用性. 以纯离子液体为参考态, 用实验数据分别拟合了Pitzer-Simonson (PS)方程、Pitzer-Simonson-Clegg (PSC)方程和简化PSC方程, 得到了这些理论模型的体积参数值. 从拟合偏差来看, PSC方程比PS方程有更好的适用性. 同时还可看出, PSC方程比只有三个参数的简化PSC方程有更小的拟合标准偏差和更好的相关系数.     

过渡金属催化下的烯烃硼氢化反应

本文综述了在过渡金属尤其是铑络合物催化下烯烃与CB ( 邻苯二酚硼烷 ) 的硼氢化反应在化学、位置和立体选择性的进展, 对它们的机理也进行了讨论。     

Raman紫外双共振研究C2H2分子的碰撞转动弛豫

本文利用受激Raman抽运,选择性地制备了C₂H₂分子电子基态的红外非激活振动能级的单一转动态(X¹∑_g⁺,v″₂=1,J″=9,11,13),并从紫外激光诱导的A¹Au(v′₃=1)←X¹∑_g⁺(v″₂=1)荧光谱,直接测定上述三个转动态的C< 关键词：     

Sparse Bayesian reconstruction method for multispectral bioluminescence tomography

We present a sparse Bayesian reconstruction method based on multiple types of a priori information for multispectral bioluminescence tomography （BLT）. In the Bayesian approach, five kinds of a priori information are incorporated, reducing the ill-posedness of BLT. Specifically, source sparsity characteristic is considered to promote reconstruction results. Considering the computational burden in the multispectral case, a series of strategies is adopted to improve computational efficiency, such as optimal permissible source region strategy and node model of the finite element method. The performance of the proposed algorithm is validated by a heterogeneous three-dimensional （3D） micron scale computed tomography atlas and a mouse-shaped phantom. Reconstructed results demonstrate the feasibility and effectiveness of the proposed algorithm.     

纳米氢氧化铜一步合成三乙氧基硅烷

对反应所用的国产硅粉进行了处理,发现处理后硅粉性能的较大变化.合成了纳米氢氧化铜催化剂并用于合成含氢三乙氧基硅烷(HSi(OC2H5)3),对催化剂进行了表征并与市售的分析纯进行了比较,发现对于这类反应可能是由于结构性能影响催化剂的活性.     

定日镜面形精度检测中的三坐标扫描系统的精度分析

塔式太阳能热发电站的定日镜面形精度以法线误差来描述,在采用激光束偏转扫描方法检测时,为达到要求的检测精度,需结合光学测头的性能对三坐标扫描系统提出相应的精度要求。通过对扫描过程的建模,定量分析了三坐标系统的精度对测量结果的影响,为合理地选择三坐标系统的精度指标提供依据。     

Sagnac干涉仪的几何参量计算

根据空间调制干涉成像光谱仪对视场的要求和小型化目标,通过对分体型Sagnac干涉仪的结构与光路进行分析,研究了Sagnac干涉仪的几何参量与入射光线视场角和孔径之间的关系.推导出满足视场要求的最优化几何参量以及满足横向剪切要求的几何参量修正量,并将其推广到实体型Sagnac干涉仪中,用于指导干涉成像光谱仪的结构设计与优化.