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911.
In this work, poly(fluorocyclopentenyl)siloxane (FPCS) was obtained via a single electron transfer addition reaction of poly(cyclopentadienyl)siloxane (PCS) and perfluoroalkyl iodides, and reduction reaction of the intermediates. PCS was prepared by substitution and hydrolysis reactions using methyltrichlorosilane and sodium cyclopentadienide (NaCp) as raw materials. Fourier transform infrared (FTIR), 1H NMR, and 19F NMR indicated the structures of the target polymers. The XPS results showed that the thin films prepared by dip-coating were fluorine enriched at the surface. Atomic force microscopy (AFM) image showed that on the rough surface of films, there were many pinnacles which were generated through the migration of side chain fluoroalkyl groups. The relative static contact angles of water and n-hexadecane on FPCS and PCS indicated that sodium dithionite initiated the reaction of perfluoroalkyl iodides and PCS so that FPCS was successfully synthesized. The measured surface energy of PCS was 2.57 × 10?2 N/m; while FPCS was 2.14 × 10?2 N/m, which represented better liquid repellent property compared to PCS. 相似文献
912.
在溶剂热条件下,5-羧酸-1-萘膦酸(5-pncH3)和稀土硝酸盐反应合成得到3例萘羧酸膦酸镧系配合物:[Pr (5-pnc)(H2O)]·2H2O (1)、[Sm (5-pnc)(H2O)]·H2O (2)和[Eu (5-pnc)(H2O)]·H2O (3)。采用单晶X射线衍射、粉末X射线衍射、元素分析、红外光谱、热重分析和荧光光谱对配合物进行了表征。晶体结构表明,每个七配位的镧系离子由来自5个膦酸盐配体的6个O原子和来自1个配位水分子的一个O原子配位。[LnO7]通过O—C—O、O—P—O或—O—单元连接成一维双金属链结构,一维双金属链再进一步由萘羧酸膦酸配体(5-pnc3-)连接成三维开放骨架结构。荧光性质研究表明,配合物3在330 nm的激发光下,发射Eu的红色特征荧光,而配合物1和2在蓝光区显示出非常宽的配体中心发射带。 相似文献
913.
《Physics and Chemistry of Liquids》2012,50(3):175-180
Abstract In this work, new definitions of the normalized temperature and surface tension are proposed which result in a single plot for the surface tension of molten alkali metals. The functional dependence of the reduced surface tension on the reduced temperature can be adequately described by a straight line; the intercept and slope have been obtained using the linear regression approach. The method proposed herein predicts the values of surface tension at various temperatures with an average error of about 5%. 相似文献
914.
Ricardo de Aldama 《Mathematical Logic Quarterly》2013,59(3):201-205
We prove that in a group without the independence property a nilpotent subgroup is always contained in a definable nilpotent subgroup of the same nilpotency class. The analogue for the soluble case is also shown when the subgroup is normal in the ambient group. 相似文献
915.
In this paper, we consider a hybrid projection method for finding a common element in the set of fixed points of a infinite family of asymptotically quasi-?-nonexpansive mappings and in the set of solutions of a generalized mixed equilibrium problem. Some strong convergence theorems of common elements are established in a uniformly smooth and strictly convex Banach space which has the Kadec-Klee property. The results presented in the paper improve and extend some recent results. 相似文献
916.
A two-dimensional (2D) numerical model is developed for the wave simulation and propagation in a wave flume.The fluid flow is assumed to be viscous and incompressible,and the Navier-Stokes and continui... 相似文献
917.
Polypropylene-block-poly(vinylpyrrolidone) copolymer was synthesized through the esterification of dicarboxyl-terminated polypropylene with monohydroxyl-terminated poly(vinylpyrrolidone) and used as a macromolecular surface modifier to improve the surface hydrophilicity of PP. The results of ATR-FTIR and contact angles measurements indicated that PP-b-PVP could diffuse preferably onto the surface by the inducement of high energy interface and lower the water contact angle of polypropylene. Lower loading and lower molecular weight of PP and PVP segment would result in higher surface selective enrichment. 相似文献
918.
919.
I. Babushkin 《Physics letters. A》2010,374(6):896-900
We study deviation from the Poissonian statistics of the frequency spacing distribution, appearing due to coupling of polarizational and transverse degrees of freedom in a perfectly square vertical cavity surface emitting laser. The deviation can be controlled by strength of the intracavity anisotropy and its alignment to the device boundaries. 相似文献
920.