Investigation of chemical decomposition of CCl4 on TiO2 near room temperature

Dissociative adsorption of CCl₄ on TiO₂ at 35 °C has been studied by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and electron spin resonance. CCl₄ decompose to form CO, CO₂, and CO₃ on the surface, at such a low temperature, in which CO₂ formation is not from CO oxidation on TiO₂, but CO₃ can be produced by CO and CO₂ adsorption. The Cl generated from CCl₄ decomposition is left on the surface and bonded to titanium ions. Mineralization of CCl₄ on TiO₂ involves the lattice oxygens. Thermodynamical driving force and possible reaction routes for CO and CO₂ formation in the CCl₄ decomposition on TiO₂ are discussed.     

Synthesis and cyclization of 1-arylalk-1-ene-3,5-diynylamines

An investigation of the reaction of 1-lithio-1,3-diynes, generated in situ, with nitriles has been carried out. In the case of aromatic nitriles 1-arylalk-1-ene-3,5-diynylamines are formed, which undergo dimerization and cyclization on isolation, giving 3-(alka-1,3-diynyl)-4-(alk-2-ynyl)-2,6-diarylpyridines. The effect of the nature of the substituent in the benzonitrile molecule on the selectivity of the reaction and the yield of the products has been determined. A scheme is proposed for the conversions and the structures of the intermediates have been established. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 701–710, May, 2006.     

Microstructure of laser melted Al18B4O33w/2024Al composite

The microstructure of a laser treated Al₁₈B₄O₃₃w/2024Al composite has been investigated using transmission electron microscope (TEM), low-angle (glancing angle) X-ray diffraction (XRD) techniques. Various surface microstructures were observed in the laser treated composite. The Al₁₈B₄O₃₃ whisker on the surface of the composite was decomposed during laser surface melting, various decomposition products were studied in the laser treated composite. Eutectic phases and the precipitation in the matrix of the composite with laser-treated were observed. The main phases detected in the molten zone were aluminum and decomposition products Al₂O₃. The effect of laser treatment on the hardness of the composite was also examined. A surface hardness of 400 Hv was noted.     

Novel intramolecular cyclization of N-alkynyl heterocycles containing proximate nucleophiles

Intramolecular cyclization of 2-acyl-1-propargyl-1H-indoles in the presence of ammonia provides an easy entry to pyrazino[1,2-a]indole nucleus.     

Bayesian estimation of keyword confidence in Chinese Continuous speech recognition

In a syllable-based speaker-independent Chinese continuous speech recognition system based on classical Hidden Markov Model(HMM),a Bayesian approach of keyword confidence estimation is studied,which utilizes both acoustic layer scores and syllable-based statistical language model(LM) score.The Maximum a posteriori(MAP) confidence measure is proposed,and the forward-backward algorithm calculating the MAP confidence scores is deduced.The performance of the MAP confidence measure is evaluated in keyword spotting application and the experiment results show that the MAP confidence scores provide high discriminability for keyword candidates.Furthermore,the MAP confidence measure can be applied to various speech recognition applications.     

X波段盘圈加速结构热阴极微波电子枪的研究

介绍了采用盘圈(DAW)加速结构在11.43GHz下研制的热阴极微波电子枪注入器，分析了注入器中DAW加速结构支撑杆对于微波特性的影响以及加速结构中的模式重叠问题. 针对该结构的强腔间耦合以及次临近耦合不能忽略的特点，对其调谐方法进行了分析研究.给出了该长腔链热阴极微波电子枪注入器的物理设计及粒子动力学计算结果，电子能量为5—6MeV，脉冲流强为40mA，电子束发射度为3.4πmm.mrad. 该微波电子枪的加工焊接已经完成，文中给出了其冷测结果.     

直径不超过4的树的割宽

§ 1　IntroductionThe cutwidth problem for graphs,as well as a class of optimal labeling and embed-ding problems,have significant applications in VLSI designs,network communicationsand other areas (see [2 ] ) .We shall follow the graph-theoretic terminology and notation of [1 ] .Let G=(V,E)be a simple graph with vertex set V,| V| =n,and edge set E.A labeling of G is a bijec-tion f:V→ { 1 ,2 ,...,n} ,which can by regarded as an embedding of G into a path Pn.Fora given labeling f of G,th…