聚合物微结构的显微学研究

本论文研究工作的目的是使用透射电子显微镜技术和原子力显微镜技术来观察研究不同聚合物薄膜样品的微结构，包括结晶结构、表面微结构以及超分子结构。研究的意义在于更广泛和更深刻的理解聚合物凝聚态结构，建立聚合物结构与性能的内在联系。通过附生结晶的方法，第一次解决多年来间规聚丙烯亚稳晶型11难以单独熔体结晶获得的问题，得到了单晶。用电子衍射倾转技术结合计算机模拟技术，从分子水平上分析解释了同手性螺旋构象亚稳晶型Il附生机理和产生的原因，并确定了附生接触面是晶型11的晶面C110)_(II)。首次发现附生的控制因素除了样品和基底接触面之间的几何匹配外，两接触表面拓扑空间的一致性也是另一重要因素。首次用熔体结晶方法获得间规对氯聚苯乙烯的单晶。通过电子衍射技术和电子晶体学的研究，得到其单晶的晶胞参数为：a = 15.83A，b = 18.48A和c = 5.10A，空间群为Phnm 0并对其衍射进行计算机模拟，给出结晶结构的模型，确定了间规对一氯聚苯乙烯单晶的结晶结构和堆砌方式。同时一，本论文刘‘高密度聚乙烯高取向薄膜和氯代的聚芳醚酮单晶的表面微结构进行了分子级水平的研究，首次得到其表面的高分辨原子力图像。另外，本论文还对带有十二烷基侧链的聚对苯磺酸在溶液中形成的超分子结构—胶束的聚集态进行了研究，得到的关于胶束结构的信息与光散射数据相一致，第一次直观的观察到单根胶束的形貌。

Detour behavior changes associated with prenatal morphine exposure in 11-day-old chicks

The central nervous system exhibits remarkable plasticity in early life. Prenatal morphine exposure may induce adverse behavioral effects on the neonate and the developing offspring. In the present study, we investigated the effect of prenatal morphine exposure (daily from embryonic days 12-16, 20 mg/kg) on 11-day-old chicks using two forms of spatial paradigms: one trial detour behavior task in which animals must bypass an obstacle to reach the desired goal without any training and detour learning task which required several trials of training to reach the detour criterion. The results showed that, on the condition that chicks could successfully detour in the first trial, morphine exposed chicks exhibited longer detour latency to finish the task, coupled by a preference for turning right versus turning left. In contrast, no significant difference in learning and memory was found in detour learning task between morphine exposed chicks and saline chicks. These findings suggest specific behavioral changes associated with prenatal exposure to opioids during mid to late gestation, also raise attention to the possible health hazard from pregnancy drug use in everyday life. (C) 2010 ISDN. Published by Elsevier Ltd. All rights reserved.

Crystal transitions of Nylon 11 under drawing and annealing

The crystal transitions of Nylon 11 annealed and drawn at different temperatures (T-d) with different drawing ratios (n) were investigated by wide-angle X-ray diffraction (WAXD). The alpha -form of Nylon Il could be transformed from the delta'-form by annealing at high temperature, The results showed that the crystal transitions of Nylon 11 strongly depended on the thermal history and the conditions of drawing. The delta'-form Nylon Il could he gradually transformed into the alpha -form when it was drawn at high temperature and the alpha -form was only partly transformed into the delta'-form when it was drawn at low temperature. This should be due to the effect of the competition between thermal inducement and drawing inducement. The thermal inducement was favorable to producing the alpha -form, while the drawing inducement was favorable to producing the delta'-form. (C) 2001 Elsevier Science Ltd. All rights reserved.

The W-11-4A platform comprehensive strength monitoring system

A comprehensive strength monitoring system used on a fixed jacket platform is presented in this paper. The long-term monitoring of W-11-4A platform achieved. Structural responses (strain and acceleration) at selected locations, as well as associated environmental parameters, have been obtained. The emphasis of the paper is placed on the system design, and the instrumentation and operation methodology employed in the monitoring of the structural responses. The performance of the system and the characteristic results obtained during its 13-month operation are also summarized.

涠11-4平台结构动态响应监测结果分析(涠11-4平台原位监测研究之二)

本文总结了针对涠１１－４平台一年多时间的应变和加速度监测数据的处理分析工作，详细介绍了所用的数据处理方法，给出了应变数据的统计结果及长期分布规律。通过对应变和加速度信号进行频谱分析，揭示了平台在多种环境条件下的振动特性。

涠11-4平台综合强度监测技术及实施运行系统(涠11-4平台结构原位监测研究之一)

本文介绍了一种固定式导管架平台综合强度监测系统，它用于对涠１１－４平台关键部位的应力、加速度及与结构响应相关的环境参数进行长期监测。讨论的重点内容是结构响应的测量方案、设备及实施方法，并对运行结果作了说明

Molecular dynamics studies on the local disordering of σ3 and σ11 grain boundaries in aluminium bicrystal

Molecular dynamics (MD) simulations using Morse interaction potential are performed in studies of [110] symmetrical tilt grain boundary (GB) structures with mis-orientation angles 50.5 degrees(Sigma 11), 129.5 degrees(Sigma 11), 70.5 degrees(Sigma 3) and 109.5 degrees(Sigma 3) at various tempratures. The GB structures are found to start local disordering at about 0.5T(m)(T-m is the melting point of aluminium) for 50.5 degrees(Sigma 11), 0.32T(m) for 129.5 degrees(Sigma 11) and 0.38T(m) for 70.5 degrees(Sigma 3), respectively. These results agree with conclusions deduced from the anelastic measurements. But, for twin-boundary structure 109.5 degrees(Sigma 3), this disordering has not been found even when temperature increases up to 0.9T(m).

TiC原位增强块状Cu_(47)Ti_(34)Zr_(11)Ni_8非晶合金复合材料

在电弧炉中利用吸铸法制备了直径1-4 mm的原位生成TiC和β-Ti枝晶联合增强的块状Cu47Ti34Zr11Ni8非晶合金复合材料.DSC热分析结果表明,原位生成TiC颗粒的引入,没有影响基体合金的非晶形成能力.用OM,XRD,SEM,EDS等方法研究了复合材料的相组成、微观组织以及成分分布,结果表明,TiC颗粒作为异质形核中心促进了β-Ti枝晶的形成,形成了TiC颗粒和β-Ti枝晶联合增强的块状Cu47Ti34Zr11Ni8非晶合金复合材料,而且β-Ti枝晶的尺寸和数量与TiC颗粒的多少以及试样的尺寸有关.室温压缩试验表明,同单相非晶合金相比,块状Cu47Ti34Zr11Ni8非晶合金复合材料提高了抗压强度及塑性.

第11届国际快淬和亚稳材料会议简介

第11届国际快淬和亚稳材料会议于2002年8月24~30日在英国牛津大学召开，本次会议由牛津大学材料系承办． 200多名来自欧洲、美国、加拿大、日本、韩国、印度、巴西、澳大利亚、新西兰、中国等29个国家的代表参加了本次大会．会议宣读口头报告244篇，张贴论文117篇，其中包括大会报告11篇，邀请报告31篇．会议论文经严格评审后由Materials Science and Engineering A杂志选择收录．下届会议将于2005年在韩国举行．

涠11-平台结构强度全尺度原位监测研究

以力学为主线而进行的多学科综合的研究。主要工作包括平台结构应力、加速度和风、浪、流环境的监测与分析,疲劳分析和寿命估算,极端环境条件下平台人员工作安全性评估,以及数据的采集和处理技术。研究结果给定了与海洋平台结构设计和运行安全密切相关的力学规律和重要资料,为平台结构的强度设计与评估提供了实用依据。

IL-8-induced L-selectin shedding regulates its binding kinetics to PSGL-1

L-selectin plays a crucial role in inflammation cascade by initiating the tethering and rolling of leukocytes on endothelium wall. While many L-selectin molecules are rapidly shed from the cell surface upon activation, the remaining membrane-anchored L-selectin may still play an important role in regulating leukocyte rolling and adhesion with different binding kinetics. Here we developed an in vitro model to activate Jurkat cells via interlukin-8 (IL-8) and quantified the two-dimensional (2D) binding kinetics, using a micropipette aspiration assay, of membrane-anchored L-selectin to P-selectin glycoprotein ligand 1 (PSGL-1) ligand coupled onto human red blood cells (RBCs). The data indicated that L-selectin shedding reduced the amount of membrane-anchored L-selectin and lowered both its reverse and forward rates. These results suggested that the rolling dynamics of activated leukocytes was determined by two opposite impacts: reducing the surface presentation would enhance the rolling but lowering the kinetic rates would decrease the rolling. This finding provides a new insight into understanding how L-selectin shedding regulates leukocyte rolling and adhesion.