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981.
983.
Alinka Lépine-Szily 《Hyperfine Interactions》2001,132(1-4):35-57
Nuclear masses and binding energies are an important input for nuclear models, constituting strong constraints far from the
β-stability valley. During the last decade, new experimental techniques for the production of exotic nuclei and the measurement
of their mass were developed. The present paper gives an overview of these techniques.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
984.
对于某种母材和接头形式,当有多种焊接方法可实现焊接时,依据优化设计的思想.建立评价函数.用计算机对焊接方法进行优化设计.本文采用VB编制程序.当用户输入焊缝基本情况和对焊接质量、焊接效率及生产成本的要求时.即可得到最优、次优的几种焊接方法以供用户选择.并可选择打印某方法的焊接工艺卡片. 相似文献
985.
Taking the enantiotopic chapter of organic chemistry as an example, this paper explores the teaching reform to form the ability and habit of lifelong learning by improving students' dominant position in learning and to guide undergraduates to cultivate the right achievement motivation. It also tries to provide useful references for the teaching of specialized courses in colleges and universities. 相似文献
986.
H. Hussain B. H. Tan C. S. Gudipati Y. Liu C. B. He T. P. Davis 《Journal of polymer science. Part A, Polymer chemistry》2008,46(16):5604-5615
Amphiphilic diblock copolymers of polystyrene (PS) and poly(N‐vinylpyrrolidone) (PNVP) were prepared by a combination of ATRP and MADIX. Well‐defined PS with bromine end group was synthesized by ATRP in bulk at 110 °C using (1‐bromoethyl) benzene as an initiator. The Br‐ end group was then converted to xanthate as verified by 1H NMR spectroscopy, elemental analysis, and UV‐spectroscopy. PS‐b‐PNVP copolymers were produced by MADIX of NVP in bulk at 60 °C using PS‐xanthate as a macro‐chain transfer agent and the kinetics of polymerization were investigated. The structures of PS‐b‐PNVP were characterized using GPC and 1H NMR. Amphiphilic PS‐b‐PNVP could form spherical micelles with PS cores and PNVP shells in aqueous solution as confirmed by 1H NMR and laser light scattering (LLS). The values of critical micelle concentration of PS‐b‐PNVP and the average aggregation number of PS‐b‐PNVP in the micelles were measured using pyrene as a probe and static LLS, respectively. The aggregation number increases concomitantly with temperature (10–50 °C), but the hydrodynamic radius of the micelles remains almost constant over the same temperature range, which may indicate shell dehydration at a higher temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5604–5615, 2008 相似文献
987.
988.
唐雪平 《数学的实践与认识》2008,38(22)
讨论了一般二维井眼轨道设计问题.建立了二维轨道设计一般数学模型,根据轨道设计约束方程,可任意选择两个设计参数作为未知数进行求解,得到了全部解析计算公式.这种方法设计计算简单、精确、快速、灵活,具有普遍适用性.可广泛用于二维定向井、水平井和多目标井的设计,为井眼轨道设计提供了理论依据. 相似文献
989.
990.
BACKGROUND: Selective recognition and binding of IgG molecules is the basis for a host of immunological and affinity purification techniques. Capture of an IgG in these procedures relies chiefly on its interaction with one of a variety of reengineered bacterial receptors which bind to the Fc region of IgG molecules with very high affinity. While this interaction is extremely efficient in trapping IgG molecules, the tight interaction between the binding partners often requires denaturing conditions for disruption of the complex, which can adversely affect the yield of purified IgG and also limit the lifetime of the receptor matrix. An effective receptor/IgG binding system which could be modulated by less extreme conditions is of considerable general interest. RESULTS: We describe the properties of a series of modified Fc receptor domains which are competent to bind IgG with high affinity but which can be reversibly unfolded upon addition of modest amounts of transition metal ions. Data are presented demonstrating loss of the secondary structural content of the domains as a function of increasing metal concentration, with a concomitant decrease in IgG binding affinity. Variants of the Fc receptor differing at a single amino acid position display increased sensitivity to metal-induced unfolding, while retaining comparable IgG binding ability in the absence of metal. CONCLUSIONS: The interaction of this series of Fc receptors with metal ions abolishes IgG binding, but removal of metal ions allows refolding of the domains with restoration of the IgG binding function. Examples of the utility and potential applications of these metal-modulated IgG binding domains are discussed. 相似文献