Use of a long-spacer-side-chain liquid crystalline polysiloxane containing a crown ether as a stationary phase for capillary gas chromatography

A new kind of side chain liquid crystalline polysiloxane containing a crown ether with a longer spacer (PSC-11) has been prepared and coated on a fused silica capillary column. The main chroma-tographic characteristics including efficiency, polarity, and selectivity have been examined. The phase exhibits the retention properties of both liquid crystal and crown ether stationary phases and possesses higher efficiency and better selectivity than PSC-3, which has a shorter spacer between the main polysiloxane chain and liquid crystalline side chain.     

三维内肋管内插入螺旋扭带的强化传热实验

本文分别以水和乙二醇为工质，在Ｒｅ数范围为：６００～４００００，Ｐｒ数范围为：５．５～１１０之间，对四根分别插入三种不同扭率螺旋扭带的三维内助管内的换热和流阻特性进行了实验研究。结果表明：三维内肋管内加装扭带的强化传热技术适用于低Ｒｅ数下高Ｐｒ数工质的管内对流换热强化。根据实验值得到了流阻和换热关联式。     

低功率泵浦Ti：Al2O3自锁模激光器

本文报道了低功率泵浦的Ｔｉ：Ａｌ２Ｏ３激光器实现了稳定的自锁模运转，锁模脉冲宽度为１８０ｆｓ。分析了激光器的结构及工作特性。     

灰色Verhulst模型的样条插值函数的残差修正

本用样条函数对灰色Verhulst模型的残差序列进行插值拟合，然后作用于二阶线性微分方程，并以此修正原模型，得到一种新的预测模型的数值解，提高了拟合的精确度。     

Yb原子高激发态的斯塔克光谱

采用ππ偏振激光，通过两步激发和光电离方法，在０－１５４Ｖ／ｃｍ电场范围内，测定了Ｙｂ原子ｎ－１８附近ｍ＝０的斯塔克光谱，首次把包含斯塔克效应的能量矩阵对角化方法推广到Ｙｂ原子，所获得的理论斯塔克图与实验结果基本符合，观察到低场中斯塔克簇随电场增加呈现线性结构以及＾１Ｐ１态与斯塔克簇在抗交叉过程中振子强度发生转移的现象，讨论了结构与量子亏损的关系。     

R￣d中Hausdorff维数和packing维数的确定

本文目的在于建立确定Ｒ￣ｄ中Ｈａｕｓｄｏｒｆｆ维数ｄｉｍ和ｐａｃｋｉｎｇ维数Ｄｉｍ的两个命题（定理１和定理２），进而寻求Ｒ￣ｄ中Ｈａｕｓｄｏｒｆｆ维数ｄｉｍ与ｐａｃｋｉｎｇ维数Ｄｉｍ相等的条件；这使得我们能够引入分形测度的测度论定义。     

Molecular weight dependence of diblock copolymer segregation at a polymer/polymer interface

Utilizing forward recoil spectrometry (FRES), we have determined the segregation isotherm which describes the interfacial excess z_i^* of diblock copolymers of poly (d₈-styrene-b-2-vinylpyridine) (dPS-PVP) at the interface between the homopolymers PS and PVP as a function of ?_∞, the volume fraction of diblock copolymer remaining in the host homopolymer. All the samples were analyzed after annealing at temperatures and times sufficient to achieve equilibrium segregation. The effect of the degree of polymerization of both the diblock copolymers and the host homopolymers on the segregation isotherm is investigated. When the degree of polymerization of the homopolymer is much larger than that of the diblock copolymer, the normalized interfacial excess (z_i^*/R_g), where R_g is the radius of gyration of an isolated block copolymer chain, is a universal function of that portion of the block copolymer chemical potential due to chain stretching. The existence of such a universal function is predicted by theory and its form is in good agreement with self-consistent mean field calculations. Using these results, one can predict important aspects of the block copolymer segregation (e.g., the saturation interfacial excess) without recourse to the time-consuming numerical calculations. © 1994 John Wiley & Sons, Inc.     

高等代数与解析几何一体化教学思考

本探讨了高等代数与解析几何进行一体化教学的必要性，研究了高等代数与解析几何进行一体化教学以后教学内容的协调性与教学手段的合理性，强调了数学实验在高等代数与解析几何一体化教学中的重要性。     

Formation of β‐iPP in isotactic polypropylene/ethylene–propylene rubber blends: Effects of preparation method,composition, and thermal condition

The effects of preparation method, composition, and thermal condition on formation of β‐iPP in isotactic polypropylene/ethylene–propylene rubber (iPP/EPR) blends were studied using modulated differential scanning calorimeter (MDSC), wide angle X‐ray diffraction (WAXD), and phase contrast microscopy (PCM). It was found that the α‐iPP and β‐iPP can simultaneity form in the melt‐blended samples, whereas only α‐iPP exists in the solution‐blended samples. The results show that the formation of β‐iPP in the melt‐blended samples is related to the crystallization temperature and the β‐iPP generally diminishes and finally vanishes when the crystallization temperature moves far from 125 °C. The phenomena that the lower critical temperature of β‐iPP in iPP/EPR obviously increases to 114 °C and the upper critical temperature decreases to 134 °C indicate the narrowing of temperature interval, facilitating the formation of β‐iPP in iPP/EPR. Furthermore, it was found that the amount of β‐iPP in melt‐blended iPP/EPR samples is dependent on the composition and the maximum amount of β‐iPP formed when the composition of iPP/EPR blends is 85:15 in weight. The results through examining the effect of annealing for iPP/EPR samples at melt state indicate that this annealing may eliminate the susceptibility to β‐crystallization of iPP. However, only α‐iPP can be observed in solution‐blended samples subjected to annealing for different time. The PCM images demonstrate that an obvious phase‐separation happens in both melt‐blended and solution‐blended iPP/EPR samples, implying that compared with the disperse degree of EPR in iPP, the preparation method plays a dominant role in formation of β‐iPP. It is suggested that the origin of formation of β‐iPP results from the thermomechanical history of the EPR component in iPP/EPR. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1704–1712, 2007     

白光干涉条纹变密的原因探讨

讨论了在测定透明介质折射率的过程中彩色条纹变密的现象，并在其基础上分析其成因：一是由于媒质折射率加大；二是由于平形板介质平行度不好造成楔形的倾角变大，最后在实验中验证了理论结果。