Effects of Adsorbed Polyaniline on Redox Process on MoO3 Surface

The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press.     

奥尔堡PBL模式对提升有机波谱分析教学效果的启示

概述了有机波谱分析课程教学中存在的主要问题，介绍了奥尔堡PBL模式的主要特点和优势，分析了将奥尔堡PBL模式用于有机波谱分析课程教学的必要性和可行性，并从课时分配、教学内容、教学方式和考核方式等4方面提出了教学改革方案，旨在提高教学效果。     

Synthesis of heterocyclic thiosulfonates

[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity.     

Determination of trace impurities in iron and nickel-base alloys by graphite furnace atomic absorption spectrometry

Five approaches to the determination of trace amounts of lead, bismuth, thallium, selenium, tellurium, and silver in iron and nickel-based alloys were investigated. While all procedures produced satisfactory results, direct techniques yielded a significant times advantage over separation schemes. Matrix effects made calibration curves an impractical approach. A spiking technique was used to generate data on a wide range of standard alloy samples.     

A Continuous-Wave Ho：YA103 Laser with Output 8.5 W Pumped by a 1.91μm Laser at Room Temperature

A cw high efficient Ho：YAI03 laser pumped by 1.91 μm diode-pumped Tm：YLF laser at room temperature is realized. The maximum output power reaches 8.5 W when the incident pump power is 15.6 W. The slope efficiency is 63.7%, and the Tm：YLF to Ho：YAP optical conversion efficiency is 54.5%. The laser wavelength is 2118.3nm when the transmission of output coupler is 30%. The beam quality factor is M2 -1.39 measured by the traveling knife-edge method.     

Higher order processes in random Raman lasing

Random Raman lasers offer a unique opportunity to study many exciting dynamics of light propagation in turbid media. One of the most notable features observed to exist in the recently discovered random Raman laser is the presence of higher order stimulated Raman scattering processes. The higher order Stokes generation likely comes from photons that have the longest pathlengths, thus have the most gain. This makes these photons particularly likely to offer interesting insight into wave propagation effects such as coherent backscattering and optical Anderson localization. In this work, we use Monte Carlo simulations to investigate how these higher order processes occur and what properties they are expected to exhibit when considering only transport equation dynamics. This knowledge will allow us to look for deviations from this theory in future experiments to determine whether wavelike properties play an active role in random Raman lasing.     

Medical Uses for Polyelectrolyte Complexes

Polyelectrolyte complexes (PEC) are ionically bonded hydrogels. The resin is synthesized by coreacting linear, water-soluble ionic polymers of opposite electrical charge under carefully controlled conditions. The resulting material is insoluble in water, electrolytes, organic, or common solvents, but soluble in special ternary solvents. Optically clear membranes or shaped articles can be prepared by employing simple solvent casting and drying techniques upon resin dissolution. The equilibrium gel water content of typical, homogeneous complexes can be made to range from 30 to 90% by weight by changing the initial polyanion to polycation ratio. For almost any given charge ratio the water content can be varied from 30 to 90% by initial adjustment of the solvent composition. As the gel water content of a membrane is raised the dialytic, oxygen, and water transport increase. High water content membranes with and without glass reinforcement were shown to be extremely permeable materials. Because these hydrated complexes appeared to be chemically inert and could be tailored to be rich in either polyanion or polycation charged groups, their biocompatability was studied. Extraction, toxicity, tissue compatability, carcinogenicity, and blood contact studies on various polyelectrolyte complexes were carried out.     

Special-valuedl-groups

Special elements and special values have always been of interest in the study of lattice-ordered groups, arising naturally from totally-ordered groups and lexicographic extensions. Much work has been done recently with the class of lattice-ordered groups whose root system of regular subgroups has a plenary subset of special values. We call suchl-groupsspecial- valued. In this paper, we first show that several familiar structures, namely polars, minimal prime subgroups, and the lex kernel, are recognizable from the lattice and the identity. This then leads to an easy proof that special elements can also be recognized from the lattice and the identity. We then give a simple and direct proof thatl, the class of special-valuedl-groups, is closed with respect to joins of convexl-subgroups, incidentally giving a direct proof thatl is a quasitorsion class. This proof is then used to show that the special-valued and finite-valued kernels ofl-groups are recognizable from the lattice and the identity. We also show that the lateral completion of a special-valuedl-group is special-valued and is an a^*-extension of the originall-group.Our most important result is that the lateral completion of a completely distributive normal-valuedl-group is special-valued. This lends itself easily to a new and simple proof of a result by Ball, Conrad, and Darnel that generalizes the Conrad-Harvey-Holland Theorem, namely, that every normal-valuedl-group can be -embedded into a special-valuedl-group.This paper is dedicated to the memory of Prof. Samuel Wolfenstein, who initiated the study of normal-valuedl-groups and recognized early the importance of special-valuedl-groups.Presented by L. Fuchs.