喷气Z箍缩内爆等离子体的雪铲模型

 在喷气Z pinch内爆等离子体研究中，雪铲模型是一种常用的、比较简单的物理模型。根据实验中提供的电流波形，负载线质量和初始半径，可以通过雪铲模型来估算内爆到心的时刻。根据一维运动方程和不同构形下的解析解以及部分实验结果相结合，讨论了雪铲模型的适用范围。数值计算的内爆时间和实验（Gamble II, Double EAGLE, BLACKJACK 5）测量值符合得较好。结果表明，雪铲模型在喷气Z pinch实验的负载优化设计研究中是很有参考价值的方法。     

An approximate proximal-extragradient type method for monotone variational inequalities

Proximal point algorithms (PPA) are attractive methods for monotone variational inequalities. The approximate versions of PPA are more applicable in practice. A modified approximate proximal point algorithm (APPA) presented by Solodov and Svaiter [Math. Programming, Ser. B 88 (2000) 371–389] relaxes the inexactness criterion significantly. This paper presents an extended version of Solodov–Svaiter's APPA. Building the direction from current iterate to the new iterate obtained by Solodov–Svaiter's APPA, the proposed method improves the profit at each iteration by choosing the optimal step length along this direction. In addition, the inexactness restriction is relaxed further. Numerical example indicates the improvement of the proposed method.     

面阵探测器的像点亚像素定位研究

面阵探测器可直接探测点目标图像的位置，但其定位精度受到探测器分辨率的限制。因此，亚像元精度技术得到了发展。它是利用目标像点的灰度分布特性，通过内插细分算法，确定出像点位置。可将定位精度提高1—2个数量级。本文介绍了几种实现目标像点亚像素定位的内插细分算法。对它们的计算公式、特点进行了分析，并进行了实验验证。     

Boiling heat transfer characteristics of nanofluids in a flat heat pipe evaporator with micro-grooved heating surface

An experimental study was performed to understand the nucleate boiling heat transfer of water–CuO nanoparticles suspension (nanofluids) at different operating pressures and different nanoparticle mass concentrations. The experimental apparatus is a miniature flat heat pipe (MFHP) with micro-grooved heat transfer surface of its evaporator. The experimental results indicate that the operating pressure has great influence on the nucleate boiling characteristics in the MFHP evaporator. The heat transfer coefficient and the critical heat flux (CHF) of nanofluids increase greatly with decreasing pressure as compared with those of water. The heat transfer coefficient and the CHF of nanofluids can increase about 25% and 50%, respectively, at atmospheric pressure whereas about 100% and 150%, respectively, at the pressure of 7.4 kPa. Nanoparticle mass concentration also has significant influence on the boiling heat transfer and the CHF of nanofluids. The heat transfer coefficient and the CHF increase slowly with the increase of the nanoparticle mass concentration at low concentration conditions. However, when the nanoparticle mass concentration is over 1.0 wt%, the CHF enhancement is close to a constant number and the heat transfer coefficient deteriorates. There exists an optimum mass concentration for nanofluids which corresponds to the maximum heat transfer enhancement and this optimum mass concentration is 1.0 wt% at all test pressures. The experiment confirmed that the boiling heat transfer characteristics of the MFHP evaporator can evidently be strengthened by using water/CuO nanofluids.     

非线型缩聚物的重均分子量

本文用数学期望方法研究了非线型共缩聚物的重均分子量,并推导出重均分子量表达式,将3种特例的理论曲线与实验结果相比较,两者基本相符。     

聚丙烯-聚乙烯嵌段共聚物的分子结构及性能的研究

本工作用核磁共振(~(13)C-NMR)、示差扫描量热(DSC)、动态力学分析(DMA)和扫描电子显微镜(SEM)等技术研究了将丙烯、乙烯单体两步分段共聚、预期为聚丙烯-聚乙烯嵌段共聚物的合成物(简称为聚丙烯-聚乙烯嵌段共聚物或嵌段共聚物)。结果表明,在嵌段共聚物中含有一定量的、能为正庚烷抽提出来的乙丙无规共聚物(EPR);分段共聚的产物并非预想的PP-b-PE两嵌段共聚物,而是含有多种组分的共混物;形态表征的结果表明了嵌段共聚物为多相体系,EPR和PE形成分散相以球形无规分布于PP基体中。     

盐类对4-氯-4′-羟基二苯砜钾盐真空熔融聚合的影响

聚苯砜醚是一种综合性能比较好、可在180℃长期使用的热塑性工程塑料,在国内外受到一定的重视。我们与武汉化工原料厂协作,对4-氯-4′-羟基二苯砜钾盐真空熔融缩聚合成聚苯砜醚的途径进行过一些探索,得到了较好的结果。但是,在实践中发现,由于这一反应速度快,放出的热量大而集中,在真空中聚合热不易导出,随着单体用量     

非法冰毒晶体中有机杂质的气相色谱-质谱分析

建立了一种适用于分析冰毒杂质的方法,并分析其形成原因。将冰毒样品溶于1 mL 0.1 mol/L pH7.0的磷酸盐缓冲液(4份缓冲液1份10%Na2CO3),杂质用0.5 mL乙酸乙酯萃取。结果共有8种物质被检出。N-甲酰甲基安非他明、N-乙酰甲基安非他明在样品中出现,说明此批冰毒由苯丙酮(phenyl-2-propanone,P-2-P)经Leuckart法合成。N-乙基甲基安非他明的检出,则说明用于合成此批冰毒的P-2-P由苯甲醛和硝基乙烷合成。从实验结果看,该法可以满足冰毒杂质分析的需要,为分析冰毒杂质成分的成因、判断冰毒样品的合成路径提供重要信息。     

铜基催化剂的制备方法对草酸二乙酯加氢反应的影响

草酸二乙酯加氢性成乙二醇的反应过程中，所用的铜基催化剂是由Ｃｕ（ＮＯ３）２与硅溶胶凝法制得的。本文考察了该催化剂的ＴＰＲ特性，结果表明，随着催化剂中Ｃｕ／ＳｉＯ２值的增大，其ＴＰＲ主峰ＴＭ峰温有所升高，这意味着催化剂的还原温度随Ｃｕ／ＳｉＯ２值的增大而提高。用ＸＲＤ和ＸＰＳ等手段对该催化剂还原后铜的含量及价态进行了考察，表明用胶凝法制备的铜基催化剂，还原后存在Ｃｕ＾ｏ和Ｃｕ＾＋两种价态。结合活性评     

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)*

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in thetemperature region 74--80.5℃ around the glass transition temperature. The film specimen was drawn to yield point followedby unloading to zero stress, then the residual deformation was held constant, while the subsequent evolution of the stress wasrecorded. An induction period was found in the course of stress evolution fol1owed by a stress step-increase. The inductionperiod decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol·K, which is attributed tothe time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than74℃, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity inthe non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results areinterpreted in terms of Perez' rheological model of a series connected Hooke spring and a Voigt element consisting of aparallel connected elastic spring and a dashpot.