基于TMS320C6201的V.32调制解调器的实现

本文详细讨论了TMS320C6201的各种特性，并基于此款DSP实现了V．32 ITU—T通信协议的调制解调器的核心发送器和接收器，给出了相关的研究结果。     

Scattering theory for a model of an atom in a quantized field

We compute the scattering operator for a simplified model of an atom interacting a with a quantized field. The field is restricted to the vacuum and one-particle sectors, and the atom has only two states. We also solve the inverse scattering problem for the same model. The methods used rely on the particular form of the interaction, which is chosen to mimic the interaction between radiation and matter.This work was partially supported by NSF Grant DMS-8922941.     

Facile esterification promoted by the triphenylstibine oxide-phosphorus sulfide (Ph3SbO/P4S10) system

Various esters are conveniently prepared by direct esterification of the corresponding carboxylic acids with alcohols catalyzed by a triphenylstibine oxide–phosphorus(V) sulfide combined system (Ph₃SbO/P₄S₁₀) under mild conditions (25–80 °C).     

载体钒氧化物中钒—吸附物分子相互作用的ESR研究

电子自旋共振技术已经用来研究还原态V_2O_5/SiO_2催化剂和各种吸附分子的相互作用。实验指出:具有四面体配位结构的V~(4+)离子是活性中心,V~(4+)和CH_2OH,HCl,CH_3CN分子的相互作用导致形成八面体配位结构的表面VO~(2+)络合物,它们的ESR和成键参数计算指出不成对电子主要定位在钒离子的d轨道上。77 K下吸附O_2分子已经观察到氧自由基的ESR信号,但吸附乙烯和丙烯不能改变V~(4+)离子的配位结构。     

n-Ge样品中的反常伏安特性

模型反型层模型，对n-Ge中的反常伏安特性进行了定量计算，得到了与实验一致的结果。     

Factors controlling electron transfer reactions and stabilisation of uncommon oxidation states of chromium

Some experimental approaches to seek semi-quantitative understanding of factors controlling outer sphere electron transfer reactions of some transition metal complexes have been made. The relative importance of nuclear and electronic factors to outer sphere processes has been examined. By the manipulation of Franck-Condon or nuclear factors, it has now been possible to gain access into the chemistry of chromium in unusual oxidation states. An example of a reorganisation controlled electron transfer reaction involving Cr(IV)-Cr(III) system has been demonstrated. The bimolecular rate of reduction of diperoxoaquaethylenediamine chromium(IV) and diperoxodiethylenetriamine chromium(IV) is independent of the nature of th reductant employed viz. Fe²⁺ or VO²⁺ indicating that the generation of6 coordinate Cr(IV) species from7 coordinate of diperoxochromium(IV) reactant may be rate limiting. Similarly by increasing the barrier for the6 coordinate to4 coordinate structures through equatorial coordination of macrocyclic ligands, it has now been possible to detect through cyclic voltommogram the formation of relatively stable Cr(IV) species in the electrochemical oxidation of Cr(Me₄[14] tetraene)(H₂O) ₂ ³⁺ in aqueous sulphuric acid media. The kinetics and mechanism of the cerium(IV) and iodosyl benzene oxidation of Cr(salen)(H₂O) ₂ ⁺ and Cr(salprn)(H₂O) ₂ ⁺ have been investigated and kinetic and spectroscopic evidence for the formation of Cr(IV) transients and stable Cr(V) products has been presented. The relative importance of Franck-Condon factors in the oxidation of Cr(III) to Cr(IV) and Cr(V) states in different macrocyclic and multidentate ligand environments has been discussed.     

Synthesis and properties of propylammonium polyvanadates

Summary Propylammonium (n-Pa) and isopropylammonium (i-Pa) meta- and decavanadates, (n-Pa)VO₃, (i-Pa)VO₃, (n-Pa)₅HV₁₀O₂₈·H₂O, (n-Pa)₄H₂V₁₀O₂₈, (i-Pa)₆V₁₀O₂₈·4H₂O, and (i-Pa)₄H₂V₁₀O₂₈, were prepared. The physico-chemical properties of the compounds prepared with polyanion of the same composition depend mainly on the cation-anion interaction.

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Synthese und Eigenschaften von Propylammoniumpolyvanadaten

Zusammenfassung Es wurden Propylammonium-(n-Pa) und Isopropylammonium-(i-Pa)-meta- und-decavanadate (n-Pa)VO₃, (i-Pa)VO₃, (n-Pa)₅HV₁₀O₂₈·H₂O, (n-Pa)₄H₂V₁₀O₂₈, (i-Pa)₆V₁₀O₂₈·4H₂O und (i-Pa)₄H₂V₁₀O₂₈ hergestellt. Die physikalisch-chemischen Eigenschaften der Verbindungen mit gleichem Polyanion hängen hauptsächlich von der Kation-Anion-Wechselwirkung ab.

     

一种基于DSP的V.17Soft Modem实现方案

介绍了传真调制解调标准ITU-TV.17,分析了调制解调器的纯软件实现方法—SoftMo-dem的特点和关键技术,给出了一种基于TMS320C6201定点DSP的实现方案。该方案可以完全实现V.17的各项功能。     

{1 1 1} Quantum wells of dilute nitrides grown on GaAs by molecular beam epitaxy

Dilute nitrides are promising alloys in view of extending potential micro- and opto-electronics applications of GaAs technology. Orientation effects on nitrogen incorporation in GaAs have been scarcely addressed. Here, GaAsN on (1 0 0) and on As(B)- and Ga(A)-rich (1 1 1) substrates was grown by molecular beam epitaxy at different substrate temperatures. Nitrogen content measured by secondary ion mass spectrometry as a function of the growth temperature highlights the influence of orientation on nitrogen incorporation. Furthermore, thermal annealing is shown to improve the optical quality of GaAsN quantum wells whatever their substrate orientations.     

高速钢激光相变强化层的耐磨性及刀具的切削性能

研究了Ｗ１８Ｃｒ４Ｖ高速钢激光相变强化层的组织和耐磨性能，并对高速钢刀具的切削性能及失效形式进行了分析讨论．结果表明：高速钢经激光相变强化后组织和性能得到了很大的改善，硬度达１００３Ｈｖ０．１以上，且韧性有显著提高，耐磨性提高了２～８倍．刀具激光相变强化后．寿命提高了３～５倍，是以磨损形式失效的。