Phenomena Affecting the Equilibrium of Al(III) and Zn(II) Extraction with Winsor II Microemulsions

The extraction of Al(III) and Zn(II) from an aqueous solution with two water-in-oil microemulsions, one containing di(2-ethylhexyl)phosphoric acid (DEHPA), was investigated to aid the understanding of the role of the extractant and the metal specific characteristics in the mechanism of microemulsion extraction. The extraction of Al with the DEHPA microemulsion increased by a factor of about 10 with respect to that in the conventional DEHPA system, whereas the extraction of Zn was lower than that in the single DEHPA system. Extraction with the DEHPA-free microemulsion was very low, showing that metal ion solubilization was not important in the mechanism of microemulsion extraction. It is proposed that the effect of the mixed microemulsion on the metal distribution coefficient is the result of the balance between a decrease in the complexation reaction yield due to the interaction between butanol and DEHPA, and the adsorption of the metal complex at the macro- and microinterfaces. The former leads to a decrease in Zn(II) extraction and the latter to Al(III) extraction synergism. Copyright 2000 Academic Press.     

机械泵驱动两相回路的实时动态模型分析

在航空航天领域,为了加速系统设计及测试进度,通常需要进行半实物实时仿真,即控制器用实物,受控对象采用数学模型。本文开发出了基于Matlab/Simulink的两相传热模块,并用其搭建了某机械泵驱动两相回路的实时动态模型。通过与实验的对比,验证了模型的可靠性,表明该模型满足实时要求,可以在下一步用于半实物仿真。     

Optical interconnections using microlens arrays

Free-space interconnection of widely spaced pixels may be implemented using microlenses, rather than conventional imaging. Advantages, problems, and studies of system capacity are discussed.     

Synthesis of n-methyl-3-carboxy-2-chloro-dibenzo[<Emphasis Type="Italic">c,f</Emphasis>][1,4,5]oxa-thiazepine s,s-dioxide and its derivatives

A new dibenzo-condensed oxathiazepinecarboxylic acid was obtained starting from the methyl ester of 2,4-dichloro-5-chlorosulfonylbenzoic acid. Derivatives were obtained from N-phenylamide and N-methylamide of 2,4-dichloro-5-chlorosulfonylbenzoic acid. Methods for the preparation of the starting aromatic sulfonyl chlorides were proposed.     

Nearly Metallic [CH(13)y]x - Importance of Solitons,Crystal Order,Hopping and Band Conduction

Polyacetylene doped in the range of one to five percent has been shown to have low Pauli susceptibility yet high electrical conductivity. Earlier studies of polyacetylene doped with iodine to these nearly metallic levels show that essentially all charges go into soliton-like states. The conductivity (σ) and thermopower (S) of many samples are in quantitative agreement with charge transport via variable range hopping among soliton-like levels. Other doped samples have a lover density of states at the Fermi level with differing σ(T) and S(T). The strong sensitivity of the density of states to disorder leads to the proposal of a parallel conduction mechanism of thermal activation of charge carriers to “high mobility” extended band states. This mechanism may dominate in less disordered samples.     

Environment Polarity in Proteins Mapped Noninvasively by FTIR Spectroscopy

The polarity pattern of a macromolecule is of utmost importance to its structure and function. For example, one of the main driving forces for protein folding is the burial of hydrophobic residues. Yet polarity remains a difficult property to measure experimentally, due in part to its non-uniformity in the protein interior. Herein, we show that FTIR linewidth analysis of noninvasive 1-(13)C=(18)O labels can be used to obtain a reliable measure of the local polarity, even in a highly multi-phasic system, such as a membrane protein. We show that in the Influenza M2 H(+) channel, residues that line the pore are located in an environment that is as polar as fully solvated residues, while residues that face the lipid acyl chains are located in an apolar environment. Taken together, FTIR linewidth analysis is a powerful, yet chemically non-perturbing approach to examine one of the most important properties in proteins - polarity.     

Algebraic study of chiral anomalies?

The algebraic structure of chiral anomalies ismade globally valid on non-trivial bundles by the introduction of a fixed background connection. Some of the techniques used in the study of the anomaly are improved or generalized, including a systematic way of generating towers of ??descent equations??.     

Microwave properties of low-density polyacetylene

The results of an initial study of the microwave properties of low-density foamlike (CH)_x are reported for intermediate dopant levels. The electrical conductivity and dielectric constant are obtained at microwave frequencies, and the results are analyzed in terms of effective medium theory. The possibility of utilizing the doped foamlike (CH)_x as an efficient microwave absorber is discussed.     

Piezo-spectroscopic determination of the ratio of electron—To phonon to hole—To phonon interaction in silicon

An investigation of the stress-dependence of the normalized wavelength-modulated absorption spectra of the TO-phonon assisted indirect transition in silicon at 77 K has yielded a value of 1.4 for the ratio of the electron-phonon to hole-phonon scattering matrix elements for the TO-phonon.