高分子共混物分散尺寸和形状的表征

本文将颗粒大小测定方法引入到高分子共混物的分散相尺寸测定中，验证了这是表征分散相尺寸可行的方法。通过对高分子共混物（PP／PA1010）脆性断面的电镜照片进行计算机处理和统计，得到分散相的粒径分布。发现各种当量直径（dF、dP、dC）均较好的符合正态分布，并求出了其分布函数，还找到了一种参数（ψW＝dC/dF）可以表征颗粒的形状。另外，讨论了刻蚀方法对测定结果的影响及误差来源等。     

分子尺寸和形状对微孔中大分子阻滞扩散的影响

研究了大分子在微孔中的阻滞扩散,描述一种同时计算分子尺寸和形状对阻滞效果影响的方法,并使用聚碳酸酯核径迹膜对4种典型形状的大分子进行了实验研究.     

高分子共混物分散相尺寸和形状的表征

本文将颗粒大小测定方法引入到高分子共混物的分散相尺寸测定中 ,验证了这是表征分散相尺寸可行的方法。通过对高分子共混物 (PP PA1 0 1 0 )脆性断面的电镜照片进行计算机处理和统计 ,得到分散相的粒径分布。发现各种当量直径 (dF、dP、dC)均较好的符合正态分布 ,并求出了其分布函数 ,还找到了一种参数 (ΨW =dC dF)可以表征颗粒的形状。另外 ,讨论了刻蚀方法对测定结果的影响及误差来源等     

保持医用管材的形状和尺寸

随着新型医用多腔管结构的日趋复杂，对挤出成型工艺也提出了越来越高的要求。利用电力调压控制系统可快捷、准确地控制内径空气和冷却槽压力，使管材在成型过程中能够保持严格的形状和尺寸。[编者按]     

侧链液晶高分子作为显示和记录材料的研究进展

从侧链液晶高分子（ＳＣＬＣＰ）的种类及合成,ＳＣＬＣＰ显示和记录类型,原理,取向稳定性几方面,评述了ＳＣＬＣＰ作为显示和记录材料的研究进展。     

1FT5交流伺服电机装配尺寸链的分析和确立

建立了影响定、转子同轴度相关尺寸的装配尺寸链,通过装配尺寸链解法的对比分析,确定了伺服电机的装配法——大数互换法。通过实测数据对比验证了所采取的工艺措施是有效的。     

冲裁刃口的几何形状、齿圉和冲裁间隙对精冲件质量的影响

前言 精冲，是二十世纪20年代于瑞士发展起来的冲裁方法。用于加工尺寸形状精确、冲裁表面尤裂纹，可作为功能表面用的冲件。开始是在精密机械工业中，用以冲1～3mm厚的铝、铜或软钢板料，时至今日，精冲件的50—60％是用于汽车工业中。特别是用以加工强度到800N／mm^2的高强度钢板，板厚可以到15mm^2与普通冲裁相比，精冲的主要特点，是模具上有压料板和反压板，需要三动压力机和很小的冲裁间隙。     

Size and Shape of Polymer Chain near a Flat Surface

The size and the shape of non-reversal random-walking polymer chains near an impenetrable, non-interacting flat surface are investigated by means of Monte Carlo simulation on the simple cubic lattice. It was found that both size and shape are dependent on the normal-to-surface distance zo of the first segment of chain. We find that the size and shape of chains, characterized by mean square radius of gyration (S2) and mean asphericity parameter (A) respectively, show similar dependence on distance z0. Both (S2) and (A) reach the maximum at Z0 = 0, then decrease with the increase of Z0 and soon reach the minimum values, afterwards they go up continuously and approach to the limit values of free chain. The similar dependence of (S2) and (A) on Z0 can be explained by a positive correlation between A and S2. However, the dependence of the correlation coefficient CA,S2 on Z0 is very complicated and deserves further study. The overall density probability of segments is also investigated. Results show that segme     

A Reptation-Based Lattice Model with Tube-Chain Coupling for the Linear Dynamics of Bidisperse Entangled Linear Polymer

A reptation-based lattice model for simulating the linear dynamics of entangled linear polymers that accounts for an essential coupling in tube-chain motions during constraint release is proposed. The predictions are tested against a representative set of dynamic oscillatory data on bidisperse polybudadiene (PBd) melts. The special feature of the current model lies in that the motion of the primitive chain coincides exactly with that of the ‘tube,’ so that it is possible to mimic the longitudinal relaxation that is cooperative with the lateral one (i.e., double reptation) during constraint release. The simulation is shown to capture the central feature of constraint release for the investigated system without demanding factorizability for the stress relaxation function, as usually enforced in existing tube theories. Furthermore, the simulation suggests that the longitudinal chain relaxation currently incorporated might account for an important partition of stress relaxation that had customarily been attributed to the effect of double reptation or similar tube motions alone.     

高分子构象模拟研究中的Monte Carlo方法

介绍了Monte Carlo方法及其特点,进而分析了Monte Carlo用于高分子模拟的优势,并描述了两类模拟模型。论文重点综述了近年来Monte Carlo方法在高分子构象模拟中的一些研究与应用,并展望了Monte Carlo方法在高分子构象模拟中的发展趋势和前景。     

智能型温敏形状记忆高分子材料的研究进展

综述了热致感应型形状记忆高分子材料的工作原理、形成记忆功能的方法及其分类和应用,介绍了热致感应型形状记忆纤维的生产技术和国内外研究发展状况,并对热致感应型形状记忆高分子材料的未来研究发展趋势作以评述。     

热敏形状记忆高分子材料及其应用

介绍了热敏形状记忆高分子材料及其应用。热敏形状记忆高分子材料是通过温度的变化实现形状的记忆与改变,利用其形状记忆功能,热敏形状记忆弹性体可应用在热缩管、油田封隔器、医用外科、保险杠等领域。     

Size and Shape Control in the Bioinspired Forming of Polymeric Nanocarrier Composites

In this work, a combination of polymeric solutions and microfluidic processing has been used to generate a variety of particles from bubbles. Thus the size, size distribution and shape of the particles prepared have been controlled, for example, by processing poly(lactic-co-glycolic acid) and polymethylsilsesquioxane solutions under the correct combination of gas pressure and liquid flow rate, virus-like nanosize particles have been generated while keeping the size distribution polydispersivity to <20%, and these can play a key role in targeted drug delivery. The ability to form particles in this way with biomedical applications in focus is essential to boost a wide range of advanced drug delivery healthcare applications.     

乳液聚合瞬时乳胶粒大小和分布及其控制策略

乳液聚合中瞬时乳胶粒大小及分布与乳胶粒的形成和增长紧密相关,本文在苯乙烯,醋酸乙烯酯乳液聚合中考察了瞬时乳胶粒大小及分布。结果表明,在成核和稳定期乳胶粒增长速率较高,是控制乳胶粒大小及分布的关键阶段,由此提出了对于单体不同水溶性体系控制乳胶粒大小分布的策略,并以实验考核这些策略的合理性。     

Simulation of a flexible polymer tethered to a flat adsorbing surface

A lattice self‐avoiding polymer chain with one end attached to an adsorbing flat surface is simulated using Monte Carlo method. The chain model has z = 26 bond vectors with bond length being 1, , and on the simple cubic lattice. The dependence of the number of surface contacts M on temperature T in the unit E/k_B with E the interacting energy and k_B the Boltzmann constant and chain length N is investigated by a finite‐size scaling law M = N^?(a₀ + a₁(T ? T_c)N^1/δ + O((T ? T_c)²N^2/δ)) near the critical adsorption point T_c. It was estimated that T_c = 1.625 and the exponents ? = 0.52 and δ = 1.63. It was observed that both mean square end‐to‐end distance 〈R²〉 and mean square radius of gyration 〈R〉 reach minimum at T_c. And we discover that the asphericity parameter 〈A〉 is independent of chain length at T_c. A simple relationship is discovered between T_c and bond vector number n_b for lattice chain models, and which can be extended to nonlattice chain models by introducing an attraction range fraction f. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Size and Shape of Calcium Alginate Beads Produced by Extrusion Dripping

Alginate hydrogel beads are widely used as an encapsulation medium for biomedical, bioprocessing, and pharmaceutical applications. The size and shape of the beads are often critically controlled since in many usages the beads are monodisperse in size and spherical in shape. Extrusion dripping is a well‐known method to produce alginate beads. Nevertheless, the production of beads of desired size and spherical shape is often achieved based on one's experience or trial and error. An overview is provided on alginate properties, formulation and preparation of alginate and gelling solutions, production conditions, and post‐production treatment that may influence the bead size and shape. Various methods of bead size and shape measurement are also discussed.