Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone). V: Estimation of temperature distribution during cure process

A numerical method to estimate temperature distribution during the cure of epoxy-terminated poly(phenylene ether ketone) (E-PEK)-based composite is suggested. The effect of the temperature distribution on the selection of cure cycle is evaluated using a suggested alternation criterion. The effect of varying heating rate and thickness on the temperature distribution, viscosity distribution and distribution of the extent of cure reaction are discussed based on the combination of the here-established temperature distribution model and the previously established curing kinetics model and chemorheological model. It is found that, for a thin composite (<=10mm) and low heating rate (<=2.5K/min), the effect of temperature distribution on cure cycle and on the processing window for pressure application can be neglected. Low heating rate is of benefit to reduce the temperature gradient. The processing window for pressure application becomes narrower with increasing thicknesses of composite sheets. The validity of the temperature distribution model and the modified processing window is evaluated through the characterization of mechanical and physical properties of E-PEK-based composite fabricated according to different temperature distribution conditions.

Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone) .3. Determination of the time of pressure application

The curing temperature, pressure, and curing time have significant influence on finished thermosetting composite products. The time of pressure application is one of the most important processing parameters in the manufacture of a thermosetting composite. The determination of the time of pressure application relies on analysis of the viscosity variation of the polymer, associated with curing temperature and curing time. To determine it, the influence of the time of pressure application on the physical properties of epoxy-terminated poly(phenylene ether ketone) (E-PEK)-based continuous carbon fiber composite was studied. It was found that a stepwise temperature cure cycle is more suitable for manufacture of this composite. There are two viscosity valleys, in the case of the E-PEK system, associated with temperature during a stepwise cure cycle. The analysis on the effects of reinforcement fraction and defect content on the composite sheet quality indicates that the width-adjustable second viscosity valley provides a suitable pressing window. The viscosity, ranging from 400 to 1200 Pa . s at the second viscosity valley, is the optimal viscosity range for applying pressure to ensure appropriate resin flow during curing process, which enables one to get a finished composite with optimal fiber volume fraction and low void content. (C) 1997 John Wiley & Sons, Inc.

Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone) .4. Cure cycle simulation

Epoxy-terminated poly(phenylene ether ketone) (E-PEK) developed in this Institute is a candidate matrix resin for polymer composites as structural materials. Cure cycles for this reaction system were simulated according to the previously established processing model. It is found that for the E-PEK system, the curing process is best completed by a stepwise cure cycle comprising two isothermal processes at different temperatures, T-1 and T-2. The cure cycles over a wide range of processing parameters simulated, based on the established processing model, indicate that the processing window is width-adjustable. Analysis of the mechanical properties of the composite sheets showed that the simulated cure cycles are acceptable and reliable. (C) 1997 John Wiley & Sons, Inc.

Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone) .1. DSC characterization of curing reaction

The curing reaction process of epoxy-terminated poly(phenylene ether ketone) (E-PEK) with 4,4'-diaminodiphenyl sulfone (DDS) and hexahydrophthalic acid anhydride (Nadic) as curing agents was investigated using isothermal differential scanning calorimetry (IDSC) and nonisothermal differential scanning calorimetry (DDSC) techniques. It was found that the curing reactions of E-PEK/DDS and E-PEK/Nadic are nth-order reactions but not autoaccelerating. The experimental results revealed that the curing reaction kinetics parameters measured from IDSC and DDSC are not equivalent. This means that, in the curing reaction kinetics model for our E-PEK system, both isothermal and nonisothermal reaction kinetics parameters are needed to describe isothermal and nonisothermal curing processes, The isothermal and nonisothermal curing processes were successfully simulated using this model. A new extrapolation method was suggested. On the basis of this method the maximum extent of the curing reaction (A(ult)) that is able to reach a certain temperature can be predicted. The A(ult) for the E-PEK system estimated by the new method agrees well with the results obtained from another procedure reported in the literature. (C) 1997 John Wiley & Sons, Inc.

Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone) .2. Chemorheological modeling

Chemorheology and corresponding models for an epoxy-terminated poly(phenylene ether ketone) (E-PEK) and 4,4'-diaminodiphenyl sulfone (DDS) system were investigated using a differential scanning calorimeter (DSC) and a cone-and-plate rheometer. For this system, the reported four-parameter chemorheological model and modified WLF chemorheological model can only be used in an isothermal or nonisothermal process, respectively. In order to predict the resin viscosity variation during a stepwise temperature cure cycle actually used, a new model based on the combination of the four-parameter model and the modified WLF model was developed. The combined model can predict the resin viscosity variation during a stepwise temperature cure cycle more accurately than the above two models. In order to simplify the establishment of this model, a new five-parameter chemorheological model was then developed. The parameters in this five-parameter model can be determined through very few rheology and DSC experiments. This model is practicable to describe the resin viscosity variation for isothermal, nonisothermal, or stepwise temperature cure cycles accurately. The five-parameter chemorheological model has also successfully been used in the E-PEK systems with two other curing agents, i.e., the diamine curing agent with the addition of a boron trifluride monoethylamine (BF3-MEA) accelerator and an anhydride curing agent (hexahydrophthalic acid anhydride). (C) 1997 John Wiley & Sons, Inc.

CURE AND IONIC-CONDUCTIVITY OF A 2-COMPONENT EPOXY NETWORK POLYMER ELECTROLYTE

In order to raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a non-crystalline two-component epoxy network was synthesized by curing diglycidyl ether of polyethylene glycol (DGEPEG) with triglycidyl ether of glycerol (TGEG) in the presence of LiClO4 salt, which acts in this system as both a ring opening catalyst and a source of ionic carrier. The structure of the precursors, the curing process and the cured films have been characterized by C-13 NMR, IR, DSC and ionic conductivity measurement techniques. The electrolyte system exhibits an ionic conductivity as high as similar to 10(-5) S/cm at 25 degrees C and is mechanically self-supportable. The dependence of ionic conductivity was investigated as a function of temperature, salt content, MW of PEG segment in DGEPEG and the proportion of DGEPEG in DGEPEG/TGEG ratio.

Identification of a WSSV neutralizing scFv antibody by phage display technology and in vitro screening

White spot syndrome virus (WSSV) is one of the most significant viral pathogens causing high mortality and economic damage in shrimp aquaculture. Although intensive efforts were undertaken to detect and characterize WSSV infection in shrimp during the last decade, we still lack methods either to prevent or cure white spot disease. Most of the studies on neutralizing antibodies from sera have been performed using in vivo assays. For the first time, we report use of an in vitro screening method to obtain a neutralizing scFv antibody against WSSV from a previously constructed anti-WSSV single chain fragment variable region (scFv) antibody phage display library. From clones that were positive for WSSV by ELISA, 1 neutralizing scFv antibody was identified using an in vitro screening method based on shrimp primary lymphoid cell cultures. The availability of a neutralizing antibody against the virus should accelerate identification of infection-related genes and the host cell receptor, and may also enable new approaches to the prevention and cure of white spot disease.

瓦山安息香中苯并呋喃促雌激素合成的机理研究

雌激素是人体内重要的激素之一，具有广泛的生理功能。雌激素缺乏与许多疾病相关，如卵巢功能低下，更年期综合征以及骨质疏松等；雌激素过剩也将导致某些疾病，如乳腺癌、卵巢癌、子宫内膜癌等。目前，如何降低肿瘤组织中的雌激素水平而达到治疗肿瘤的目的，已经得到广泛的研究，但促雌激素生成或调节卵巢功能药物或其相关研究则很少。 本实验室前期的研究发现，瓦山安息香属植物果实中的乙醇提取物具有促雌激素生成作用，通过活性追踪和结构鉴定，确认促E2 生成的主要成分为苯并呋喃类化合物。苯并呋喃类化合物的作用与芳香酶有关，但其确切的作用机理有待证实和深入研究。 为了探讨安息香苯并呋喃类化合物的促雌激素合成的作用机理，拟采用如下的实验方案： 1、细胞学方面，对小鼠3T3-L1 前脂肪细胞、人乳腺癌细胞MCF-7、MDA-MB-231 以及人卵巢癌细胞OVCAR-3、OVCAR-4、OVCAR-5、OVCAR-8、IGROV1 等细胞株，采用RT-PCR 和ELISA 方法研究芳香酶Aro基因的表达和雌二醇E2 的生成，芳香酶抑制剂Formestane 作为阳性对照，研究时效曲线和量效曲线，确定安息香苯并呋喃类化合物SP25 的有效浓度和作用时间。 2、RNAi 方面，设计合成了针对人芳香酶Aro基因的3 对RNAi 序列，转染入细胞，芳香酶促进剂Forskolin 和地塞米松、芳香酶抑制剂Formestane 作为阳性对照，采用实时定量PCR 技术，研究RNA 干扰后，安息香苯并呋喃类化合物SP25 对人芳香酶Aro基因表达水平瓦山安息香苯并呋喃促雌激素合成的机理研究的影响。 3、雌激素受体方面，设计一段ERE 的雌激素调控元件，构建重组荧光素酶报告基因载体，瞬时转染人乳腺癌细胞株MDA-MB-231，建立针对雌激素受体的报告基因筛选模型，观察安息香苯并呋喃类化合物SP25 对雌激素受体的选择性和亲和力，从受体水平考察安息香苯并呋喃类化合物SP25 促进雌激素生成的药理学机理。 实验结果显示： 1、分化后的小鼠3T3-L1 前脂肪细胞、人乳腺癌细胞MCF-7 、MDA-MB-231 以及人卵巢癌细胞OVCAR-3、OVCAR-4、OVCAR-8 等细胞株具有芳香酶基因的表达。睾酮向雌二醇的转化能够被芳香酶抑制剂Formestane 所阻断，其中OVCAR-3 最适合进行下一步的RNAi研究。 2、RNAi 实验结果显示，设计的3 对RNAi 序列中R2 的干扰效果最强，相应的阴性对照C2 与R2 的表达量相差118 倍（24 小时）和19 倍（48 小时），显示R2/C2 这组序列可用于进一步的RNAi 试验。以R2 干扰OVCAR-3 细胞株，药物作用24、48 小时后，芳香酶抑制剂Formestane 与R2 相对表达量相比分别为0.83 倍和0.04 倍；芳香酶促进剂Forskolin 与R2 相对表达量相比分别为3.61 和1.84 倍；芳香酶促进剂地塞米松与R2 相对表达量相比分别为5.76 倍和3.49倍；苯并呋喃类化合物SP25 与R2 相对表达量相比分别为8.13 倍和4.59 倍。实验证实安息香苯并呋喃类化合物SP25 能够促进因RNAi 而发生基因沉默的人芳香酶Aro表达水平的上调。 3、雌激素受体实验结果显示，构建成功重组pERE-pGL3-promoter 荧光素酶报告基因载体和基于报告基因系统的雌激素受体激动剂或拮抗剂的细胞筛选模型。实验结果表明安息香苯并呋喃类化合物SP25 与雌激素受体ERα和ERβ亲和力选择性之比约为3：1 ，SP25通过与雌激素受体ERα结合作用其受体，刺激芳香酶的表达。 本课题通过RNA 干扰、ELISA、荧光实时定量PCR、报告基因筛选模型等技术手段，从细胞水平、蛋白酶水平和基因表达水平、雌激素受体水平等方面系统地研究了从瓦山安息香属植物果实中提取的苯并呋喃SP25 促进促雌激素生成的机理研究。试验结果显示苯并呋喃类化合物SP25 促雌激素生成的主要作用机制是直接促进芳香酶基因表达水平，以及与雌激素受体a 结合，刺激芳香酶活性。 Estrogen is an important hormone that has versatile physiologicalfunctions. Lack of estrogen will lead to many diseases such as lower ovarianfunction, climacteric syndrome and osteoporosis. Excessive estrogen alsoinduces breast carcinoma, oophoroma and endometrial carcinoma and otherdiseases. To depress the estrogen level in tumor tissue to cure carcinomawas widely studied, but there is only few studies reported on the induction ofestrogen and on the regulation of ovary function. We found that the extracts from seeds of Styrax perkinsiae couldpromote the synthesis of estrogen. The active compounds benzofurans wereidentified. Effect of benzofurans may be related to aromatase, but the mechanism was not clear. To reveal the mechanism of these benzofurans to promote estrogensynthesis, the following protocols were adopted: 1 Cytology: 3T3-L1 preadipocytes,human ovary carcinoma celllines OVCAR-3,OVCAR-4,OVCAR-5,OVCAR-8,IGROV1 andbreast carcinoma cell lines MCF-7 and MDA-MB-231 were usedto determine Aro gene expression and estrogen production withRT-PCR AND ELISA methods. Formestane, an aromataseinhibitor, was used as positive control. And dose-curve,time-curve and the effective concentration of SP25 were also studied. 2 Designed 3 pairs of RNAi for human aromatase gene, andtransfected into cell. Aromatase inducer Forskolin andDexamethasone, and aromatase inhibitor Formestane were usedas positive controls. We studied the change of Aro expressionlevel with SP25 by using real-time PCR after RNA interfering. 3 Estrogen Receptor: We constructed the recombined Luciferasereport vector and establish a screening system for estrogenagonist and antagon. With this system, we studied the affinity ofSP25 and estrogen receptor. Results: 1 Differentiated 3T3-L1 preadipocytes¡¢human ovary carcinomacell lines:OVCAR-3, OVCAR-4, OVCAR-8 and breast carcinomacell lines MCF-7, MDA-MB-231 had detected aromatase geneexpression.And OVCAR-3 is more suitable for further aromatasegene function research. 2 In RNAi assay, R2 has a strong interfering effcet in OVCAR-3 cellline, and ratio of C2 (the negative control) to R2 were 118 times(24 hours) and 19 times (48 hours). This means sucessful inRNA interfering. After R2 acted on OVCAR-3 cell line, the ratiosof formestane to R2 were 0.83 and 0.04 times, 5.76 and 3.49times (Dex), 3.61 and 1.84 times (forskolin) and 8.13 and 4.59times (sp25) after drug treated 24 or 48 hours respectively.These results indicated that SP25 can directly induce aromatasegene up-regulation. 3 We had constructed pERE-pGL3-promoter recombined vectorand the Luciferase report gene screening system. Luciferasereport gene assay showed that sp25 had a higher affinity with strogen receptor alpha than estrogen receptor beta, this indicated that SP25 can act on estrogen receptor and induce aromatase. Our results revealed that the mechanisms of benzofuran to promoteestrogen were the upregulation aromatase gene expression and promotion ofaromatase activity and have partially elective affinity with estrogen receptoralpha.

若尔盖湿地公路对两栖类的生态影响

本文考察了若尔盖高寒泥炭湿地公路对高原林蛙（Rana kukunoris）、倭蛙（Narorana pleskei）和岷山蟾蜍（Bufo minshanicus）的生态影响。分析了公路对两栖动物空间分布和栖息地利用的影响，并用IBM模型探讨其可能作用机制，考察了两栖动物公路死亡的季节差异及影响公路死亡空间分布的景观因素。最后通过对若尔盖高寒湿地两栖动物陆地核心栖息地的分析，为若尔盖路域栖息地的管理提供依据。 1. 对公路周边6个沼泽水凼群进行了调查，每个样地设置5条样线（距离公路10m、20m、50m、100m和150m）。调查表明，在繁殖季节(5月)，距离公路距离对高原林蛙和倭蛙的相对数量都有显著作用，其效应明显大于其他各项栖息地环境参数。公路导致高原林蛙和倭蛙在公路周边种群密度降低，其相对数量从距离公路100m处到公路边缘一直呈现逐渐降低的趋势。在繁殖季节，若尔盖高寒湿地的公路生态影响域大约在100-150m之间，这一距离远远大于森林栖息地中公路对两栖类的生态影响域（35-40 m）。 在繁殖后期（9月），对公路周边16个草地样点的样线调查表明，公路对周边高原林蛙和倭蛙密度分布并未造成显著影响。 2. 二次模型的拟合表明繁殖季节高原林蛙和倭蛙在公路周边的密度分布符合钟型曲线。前人对森林公路两侧两栖类分布的研究也显示了类似的规律。我们通过基于个体的模型，模拟在了公路边缘100单位距离内的栖息地空间，栖息地环境质量呈梯度变化，动物个体在其中通过随机运动寻找适宜的栖息地。拟合结果表明，动物个体仅仅依照简单的运动规则寻找适宜栖息地，这种活动就可以导致公路周边栖息地中的动物分布曲线出现3个局部峰。公路周边两栖动物的钟型分布曲线可能仅仅是个体寻找适宜栖息地过程中出现的临时性群体分布模式。 3. 在若尔盖高寒湿地，公路交通造成了大量两栖类死亡。但是公路两栖类动物死亡的季节分布很不均匀：5月、8月和9月死亡数量很高，而7月和10月死亡数量却很低。这种季节性差异和两栖类各个生活史阶段的迁移运动有密切的关系。利用景观参数的逻辑斯蒂回归模型显示，距离公路1000-2000m范围内的湿草地比例对三种两栖类公路死亡概率均有很强的贡献。湿草地这一栖息地类型分类中有大量的沼泽水体，是两栖类重要的繁殖点和取食点。两栖类公路死亡概率湿草地的关系从一个侧面表明，要维持一个区域较高的两栖类种群数量，需要1000-2000m半径范围内存在大面积的湿草地。 4. 高原林蛙和岷山蟾蜍不同性别和年龄个体分布点的水体距离存在显著差异。不同种类、年龄的两栖类分布点距离水体距离的差异可能是由于对水体的依赖性造成的。而相同种类、年龄段的个体中，高原林蛙雌性、岷山蟾蜍亚成体和雌性的体重与分布点距水体距离有显著负相关，这可能是因为体重更大的个体对水体的依赖性更弱。考虑到过大的陆地核心栖息地面积在实际保护工作中存在操作上的困难，因此我们认为可以以水体周边90%个体的分布区为低限确定3种两栖类的最小陆地核心栖息地。但是，在同样的水体距离-两栖类密度分布格局下，水体的面积和分形参数对最小陆地核心栖息地半径的确定有一定影响。 Ecological effects of alpine wetland road on Rana kukunoris, Narorana pleskei, Bufo minshanicus was studied in Zoige wetland. The effects of road on distribution of amphibians and its possible underline mechanism was discussed based on empirical data and computer simulation. Road killed amphibians was surveyed in different season and those landscape factor which could have impact on road killing distribution was analyses. Core terrestrial habitat of amphibians in Zoige wetland was discussed in the consideration of conservation management. 1. Six pool groups was investigated in breeding season (May) of R. kukunoris, N. pleskei. Five transects at distance of 10m, 20m, 50m, 100m and 150m from road edge was surveyed in each pool groups. There was a significant effects of distance from road edge on relative counts of R. kukunoris, N. pleskei, which is much important than effects of other environmental factors. Road caused the density of R. kukunoris, N. pleskei decreased from distance of 100m from road to 10m from road. Road ecological effect zone of alpine wetland for amphibians is about 100-150m. It is much wider than those of forest roads, which is about 35-40m. However, studies on 16 grassland near road showed no significant effect of road on amphibians after breeding season (Sep.). 2. Quadratic model fit indicated that the distribution of R. kukunoris and N. Pleskei followed a hump like curve. Previous studies on forest road showed similar results. A 100×100 habitat with gradual environment besides road was simulated with a individual-based model, and animal seek for suitable habitat with stochastic locomotion in it. Simulation results indicated that 3 density peak of animal distribution can emergent followed a simply rules. The hump like density cure could be a temporal swarm pattern during the process of individual seeking for habitat. 3. Road traffic caused mass death of amphibians in Zoige wetland. There was much road killed amphibians in May, Aug and Sep than those in July and Oct. The fluctuation of road kill could be related with migration of amphibians between seasons. Logistic regression of landscape variables indicated that wet grassland in 1000-2000m is essential to predict the probability of road kill. Wet grassland is an important breeding and forage habitat for amphibians. It also indicated that mass wet grassland in 1000-2000m is essential for maintain a big amphibian population. 4. There was significant differences among distance from aquatic site of subadults, female and males of R. kukunoris and B. Minshanicus. Possibly, it was because of their dependence on water. There was a significant negative relationship between distance from aquatic site and individuals body mass. Estimates of core habitat that are too large may make it difficult to establish protective regulations. The smallest suitable terrestrial core habitats were defined as the terrestrial habitats used during migration to and from the wetlands, and for foraging by 90% of any life stage (adults, and subadults) in a season. However, even with the same amphibian distribution pattern along the distance from aquatic sites, the radii of smallest suitable terrestrial core habitats will be varied with the fractal parameters of aquatic site.

Superfluid nuclear matter in BCS theory and beyond

Medium polarization effects are studied for S-1(0) pairing in nuclear matter within BHF approach. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.

Micro Insert: A Prototype Full-Ring PET Device for Improving the Image Resolution of a Small-Animal PET Scanner

A full-ring PET insert device should be able to enhance the image resolution of existing small-animal PET scanners. Methods: The device consists of 18 high-resolution PET detectors in a cylindric enclosure. Each detector contains a cerium-doped lutetium oxyorthosilicate array (12 x 12 crystals, 0.72 x 1.51 x 3.75 mm each) coupled to a position-sensitive photomultiplier tube via an optical fiber bundle made of 8 x 16 square multiclad fibers. Signals from the insert detectors are connected to the scanner through the electronics of the disabled first ring of detectors, which permits coincidence detection between the 2 systems. Energy resolution of a detector was measured using a Ge-68 point source, and a calibrated 68Ge point source stepped across the axial field of view (FOV) provided the sensitivity profile of the system. A Na-22 point source imaged at different offsets from the center characterized the in-plane resolution of the insert system. Imaging was then performed with a Derenzo phantom filled with 19.5 MBq of F-18-fluoride and imaged for 2 h; a 24.3-g mouse injected with 129.5 MBq of F-18-fluoride and imaged in 5 bed positions at 3.5 h after injection; and a 22.8-g mouse injected with 14.3 MBq of F-18-FDG and imaged for 2 h with electrocardiogram gating. Results: The energy resolution of a typical detector module at 511 keV is 19.0% +/- 3.1 %. The peak sensitivity of the system is approximately 2.67%. The image resolution of the system ranges from 1.0- to 1.8-mm full width at half maximum near the center of the FOV, depending on the type of coincidence events used for image reconstruction. Derenzo phantom and mouse bone images showed significant improvement in transaxial image resolution using the insert device. Mouse heart images demonstrated the gated imaging capability of the device. Conclusion: We have built a prototype full-ring insert device for a small-animal PET scanner to provide higher-resolution PET images within a reduced imaging FOV. Development of additional correction techniques are needed to achieve quantitative imaging with such an insert.

3-phenylethynyl phthalimide end-capped imide oligomers and the cured polymers

In the past decades, 4-phenylethynyl phthalic anhydride (4-PEPA) has been the most important endcapper used for thermoset polyimide. As the isomer of 4-PEPA, 3-phenylethynyl phthalic anhydride (3-PEPA) has attracted our interest. In this article, 3-PEPA was synthesized and a comparative study with 4-PEPA on curing temperature, curing rate, thermal and mechanical properties of oligomers and cured polymers was presented. The new phenylethynyl endcapped model compound, N-phenyl-3-phenylethynyl phthalimide, was synthesized and characterized.

PHASE-BEHAVIOR IN EPOXY-RESIN CONTAINING PHENOLPHTHALEIN POLY(ETHER ETHER SULFONE)

Phenolphthalein poly(ether ether sulphone) (PES-C) was found to be miscible with uncured bisphenol-A-type epoxy resin, i.e. diglycidyl ether of bisphenol A (DGEBA), as shown by the existence of a single glass transition temperature within the whole composition range. Miscibility between PES-C and DGEBA is considered to be due mainly to the entropy contribution. However, dynamic mechanical analysis (d.m.a.) and scanning electron microscopy (SEM) studies revealed that PES-C exhibits different miscibility with four cured epoxy resins (ER). The overall compatibility and the resulting morphology of the cured blends are dependent on the choice of cure agent. For the blends cured with amines (4,4'-diaminodiphenylmethane (DDM) and 4,4'-diaminodiphenylsulphone (DDS)), no phase separation occurs as indicated by either d.m.a. or SEM. However, for the blends cured with anhydrides (maleic anhydride (MA) and phthalic anhydride (PA)), both d.m.a. and SEM clearly show evidence of phase separation. SEM study shows that the two phases interact well in the MA-cured blend while the interface between the phases in the PA-cured blend is poorly bonded. The differences in the overall compatibility and the resulting morphology between the amine-cured and anhydride-cured systems have been discussed from the points of view of both thermodynamics and kinetics.

PHASE-SEPARATION IN ANHYDRIDE-CURED EPOXY-RESIN CONTAINING PHENOLPHTHALEIN POLY(ETHER ETHER KETONE)

Dynamic mechanical analysis and scanning electron microscopy were used to study phase separation of three blends of anhydride-cure bisphenol-A-type epoxy resin with phenolphthalein poly(ether ether ketone). Phase separation was observed for all the blends. The overall compatibility and the resulting morphology of the cured blends are dependent on the choice of cure agent. The phenomena have been discussed from the points of view of both thermodynamics and kinetics. The effects of the choice of hardener on phase separation are considered to be primarily due to differences between the chemical natures of the hardeners.

去甲肾上腺素参与吗啡神经适应性改变的中枢机制

That relapse still exists even after prolonged withdrawal is a difficult issue in the medical cure of drug addiction. Neuro-adaptation induced by prolonged exposure to addictive drugs is the neural mechanisms of both compulsive drug seeking and relapse.Neuro-adaptation caused by addictive drugs increases the individuals’ response to drugs and on the other hand, it reduces the response to natural reward in withdrawn individuals.There must be common neural mechanisms between the co-existing phenomena, and there must also be unique neural mechanisms in the drugs.To reveal the neuro-adaptation arising in the process from random, controllable drug-use to uncontrollable compulsive drug seeking is of great significance both theoretically and practically.Based on the above hypothesis, in order to reveal the function of alpha adrenergic receptor in compulsive drug-seeking motivation during the process of drug addiction, using sensitization of morphine-induced psychomotor activity as behavioral model, through the method of behavioral pharmacology, the neural mechanisms of alpha adrenergic receptor’s involvement in the process of addiction has been studied.The adjustment function caused by alpha receptors in medial prefrontal cortex and nucleus accumbens to morphine-induced psychomotor activity has been compared in the period of first use of drugs and in repetitive-use period. Furthermore, the effect on novelty seeking caused by alpha-receptors in relevant brain areas has also been compared. Major results are as follow: 1 After prolonged morphine exposure, rats’ response to morphine-induced psychomotor activity is strengthened and response to novel object induced reward weakened. 2 Injection of prazosin in medial prefrontal cortex will block morphine-induced psychomotor activity of naïve rats, however, it will not block that of morphine-withdrawn rats, but it will block the novelty seeking behavior of morphine-withdrawn rats. 3 Injection of clonidine in medial prefrontal cortex will block morphine-induced psychomotor effect of both naïve rats and morphine-withdrawn rats, and will block the novelty seeking behavior of morphine-withdrawn rats. 4 Injection of prazosin in nucleus accumbens will not affect the morphine-induced psychomotor effect of either naïve rats or morphine-withdrawn rats, nor will it affect the novelty seeking behavior of morphine-withdrawn rats. 5 Injection of clonidine in nucleus accumbens will block morphine-induced psychomotor effect of naïve rats, however, it will not block that of morphine-withdrawn rats, nor will it affect the novelty seeking behavior of morphine-withdrawn rats. These results show: 1 The weakening of the function of alpha1 receptors in medial prefrontal cortex and alpha2 receptors in nucleus accumbens caused by repetitive exposure to morphine is probably the cause of compulsive drug-seeking activity. 2 Blocking alpha1 receptors in medial prefrontal cortex accelerates the loss of interest in natural reward after morphine withdrawal. 3 Blocking alpha2 receptors in medial prefrontal cortex not only restrains drug-seeking motivation, but also blocks the individual’s seeking motivation for novelty stimulus, which suggests that, while selecting medicine for curing addiction, it should be considered to reduce the influence on natural reward as much as possible and to avoid major side-effect.