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Ryuhei Wakita Masanori Miyakoshi Yohji Nakatsuji Mitsuo Okahara 《Journal of inclusion phenomena and macrocyclic chemistry》1991,10(1):127-139
A series of noncyclic neutral ionophores has been synthesized by the reaction of oligoethylene glycol dihalides with 8-quinolinol. Complexation properties for alkali metal picrates were evaluated from solvent extraction and bulk liquid membrane transport experiments. Complexation profiles of the newly synthesized ionophores with a hexyl chain were similar to those of their homologues without the hexyl chain in the extraction experiments. Among them, the pentaethylene glycol derivatives showed the highest extraction efficiency and selectivity towards potassium ion. From the1H NMR spectra (400 MHz), the change in chemical shifts of the aromatic protons upon the addition of alkali metal thiocyanates suggested the existence of a stabilization effect which is caused by intramolecular stacking conformations between the quinoline rings during complexation. Aryl stacking interactions depend on the size of the cations and on the chain length of the oligoethylene glycol. The relationship between transport ability towards alkali metal cations and lipophilicity of these ionophores is also discussed. 相似文献
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Rostislav Vodák 《Mathematical Methods in the Applied Sciences》2007,30(1):43-75
We consider a sequence of curved rods which consist of isotropic material and which are clamped on the lower base or on both bases. We study the asymptotic behaviour of the stress tensor and displacement under the assumptions of linearized elasticity when the cross‐sectional diameter of the rods tends to zero and the body force is given in the particular form. The analysis covers the case of a non‐smooth limit line of centroids. We show how the body force and the choice of the approximating curved rods can affect the strong convergence and the limit form of the stress tensor for the curved rods clamped on both bases. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
77.
V. N. Odinoko V. R. Akhmetova R. G. Savchenko A. A. Fatykhov A. Ya. Zapevalov 《Russian Chemical Bulletin》1994,43(6):1084-1085
Perfluoro-1-octene was used as a model for developing a method for the preparative ozonolysis of perfluoro-1-alkenes to the corresponding perfluoro-nor-alkenals. Perfluoroheptanal was synthesized.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1146–1147, June, 1994. 相似文献
78.
R. Souzy B. Ameduri B. Boutevin 《Journal of polymer science. Part A, Polymer chemistry》2004,42(20):5077-5097
The radical co‐ and terpolymerization of 4‐[(α,β,β‐trifluorovinyl)oxy]bromo benzene (TFVOBB) with 1,1‐difluoroethylene (or vinylidene fluoride, VDF, or VF2), hexafluoropropene (HFP), perfluoromethyl vinyl ether (PMVE), and chlorotrifluroroethylene (CTFE) is presented. Although TFVOBB could be thermocyclodimerized, it could not homopolymerize under radical initiation. TFVOBB could be copolymerized in solution under a radical initiator with VDF or CTFE comonomers, while its copolymerization with HFP or PMVE were unsuccessful. The terpolymerization of TFVOBB with VDF and HFP, or VDF and PMVE, or VDF and CTFE also led to original fluorinated terpolymers bearing bromoaromatic side‐groups. The conditions of co‐ and terpolymerization were optimized in terms of the nature of the radical initiators, and of the nature of solvents (fluorinated or nonhalogenated). Various monomer concentrations in the co‐ and terpolymers were assessed by 19F and 1H‐NMR spectroscopy. The thermal and physico chemical properties were also studied. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5077–5097, 2004 相似文献
79.
以1H-NMR谱和13C双自旋回波的APT脉冲序列测定文献中尚未曾发表的化合物HC≡C-CH2-O-CCH3-O-CH2文中计算了峰强度与脉冲间隔时间的关系,讨论了各谱线的相位并区分出-CH3、-CH2、-CH和季碳。 相似文献
80.
Erkki Mäkinen 《BIT Numerical Mathematics》1987,27(3):330-339
The splay tree is a self-adjusting binary search tree which has a good amortized performance. This paper studies some properties of top-down splay trees. Different ways to charge for the primitive operations of top-down splaying are discussed. We also give some empirical results concerning the behaviour of different top-down restructuring algorithms.This work was supported by the Academy of Finland. 相似文献