Estimating the complexity of a class of path-following methods for solving linear programs by curvature integrals

In this paper we study a particular class of primal-dual path-following methods which try to follow a trajectory of interior feasible solutions in primal-dual space toward an optimal solution to the primal and dual problem. The methods investigated are so-called first-order methods: each iteration consists of a long step along the tangent of the trajectory, followed by explicit recentering steps to get close to the trajectory again. It is shown that the complexity of these methods, which can be measured by the number of points close to the trajectory which have to be computed in order to achieve a desired gain in accuracy, is bounded by an integral along the trajectory. The integrand is a suitably weighted measure of the second derivative of the trajectory with respect to a distinguished path parameter, so the integral may be loosely called a curvature integral.     

Study of cross-conjugated iso-polytriacetylenes and related oligoenynes

Two series of monodisperse cross-conjugated oligomers based on enyne repeat units have been realized. The first class of molecules, iso-polytriacetylenes (iso-PTAs, 2), was divergently synthesized using an iterative sequence of palladium-catalyzed cross-coupling reactions of vinyl triflate 5 with terminal alkynes. The second series of oligoenynes (17-20) are based on an octatetrayne backbone, and result from homocoupling of the differentially protected iso-PTA oligomers 8-11. The longest member of this series, 20, spans ca. 5.6 nm from Si atom to Si atom and is composed of a contiguous sequence of 44 sp and sp(2) carbons. The lowest energy electronic absorption band for iso-PTA dimers in the progression 13 --> 9 --> 16 is consistently red-shifted as a result of extending the cross-conjugated structure. A similar comparison within each series (i.e., 16, 6-7, or 17-20), however, suggests little effect on the electronic characteristics of these molecules as oligomer length is increased. The solid-state properties of one derivative, 17, are also described.     

Theoretical approach and the practice to the evaluation of structural parameters characterizing concentration polarization alongside ion-exchange membranes by means of dielectric measurement

As the application of a dielectric theory proposed previously (J Membrane Sci 64:153–161 (1991)), theoretical formulation and the practical procedure of dielectric analysis are developed to calculate the structural parameters such as the conductivity gradient and the thickness of the concentration polarization layer, the capacitances and the conductances of the two adjoining aqueous phases from the observed dielectric parameters. The procedure of calculation consequent upon the theoretical formulation was applied to double relaxation data observed for cation-exchange membrane systems under application of d.c. bias voltage. As a consequence, the structural parameters of concentration polarization were readily obtained with accuracy.     

酞菁钴液相催化氧化羰基硫(COS)的研究

本文首次报道在液相中，用金属酞菁催化氧化脱除羰基硫（COS）。发现COS先被水解成HS~－，HS~-再被氧化成S，酞菁钴（CoPC）的活性高于其它金属酞菁（MPC），酞菁苯环上推电子基因使酞菁的催化活性提高，双核酞菁钴的活性高子单核酞菁钴。D296树脂负载的酞菁钴的催化活性高于均相酞菁钴的活性。     

离子注入修饰电极检测硝基苯

离子注入是一种新技术，可按人们的意愿和需要，将不同的离子注入不同的基本电极表面，制成具有催化活性强，稳定性高，重现性好等特点的修饰电极。作者研究了离子注入钴和注入镍的玻碳电极在０．１ｍｏｌ／ＬＨＡｃ－ＮａＡｃ缓冲溶液中硝基苯的行为及测定。     

The uranium-Xylidyl Blue I complex and its application in linear sweep polarography

The linear sweep polarographic wave of the uranium-Xylidyl Blue I complex in ethylenediamine-1,10-phenanthroline-hydrochloric acid medium has been studied. The complex, corresponding to UO(2)(XBI)(2-)(2) with log beta' = 9.09 (by polarography), 8.81 (by spectrophotometry), is strongly adsorbed on the surface of the mercury electrode. The polarographic wave is attributed to the reduction of Xylidyl Blue I in the complex. The method is very sensitive with a detection limit of 3 x 10(-8)M. The wave height is proportional to the concentration of uranium over the range 8 x 10(-8)-7 x 10(-6)M. Solvent extraction is used to separate possible interferences. The recommended procedure has been applied to the determination of trace amounts of uranium in ores.