Quantum-Chemical Evaluation of the Protolytic Properties of Thiophenols

The enthalpies and free energies of proton affinity (PA) were calculated by the PM3 method for 27 thiophenoxide anions. For thiophenols, linear correlation has been found between the PAs and the values of pK _a measured by different authors in aqueous acetone, aqueous ethanol, and methanol media. The dependences found permit one to predict a priori the protolytic properties of thiophenols. The differential effects of aqueous ethanol media with different ethanol contents on thiophenol acidity were evaluated based on quantum-chemical data.Original Russian Text Copyright © 2004 by A. N. Pankratov and A. V. Shalabai__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 800–806, September–October, 2004.     

基于"纵横向拉开档次法"的上市公司经营业绩评价

鉴于目前已具有较全面、完整、连续的有关上市公司各项指标的纵横向数据，为充分利用数据所蕴涵的信息，本文提出运用“纵横向拉开档次”的综合评价方法，其特点是使指标权重的确定能尽量将被评价对象在纵横向拉开档次。将该法运用于安徽地方板块的18家上市公司业绩评价，获得了各公司在1999～2001年间动态发展的分析结果。     

Synthesis and characterization of wholly aromatic poly(azomethine)s containing donor–acceptor triphenylamine moieties

N‐(4‐nitrophenyl)‐4′,4″‐bisformyl‐diphenylamine was synthesized from N‐(4‐nitrophenyl)‐diphenylamine by the Vilsmeier‐Haack reaction. Soluble aromatic poly(azomethine)s (PAMs) were prepared by the solution polycondensation of N‐(4‐nitrophenyl)‐4′,4″‐bisformyl‐diphenylamine and aromatic diamine in N‐methyl‐2‐pyrrolidone (NMP) at room temperature under reduced pressure. All the PAMs are highly soluble in various organic solvents, such as N,N‐dimethylacetamide (DMAc), chloroform (CHCl₃), and tetrahydrofuran (THF). Differential scanning calorimetry (DSC) indicated that these PAMs had glass‐transition temperatures (T_gs) in the range of 170–230 °C, and a 10% weight‐loss temperatures in excess of 490 °C with char yield at 800 °C in nitrogen higher than 60%. These PAMs in NMP solution showed UV‐Vis charge‐transfer (CT) absorption at 405–421 nm and photoluminescence peaks around 462–466 nm with fluorescence quantum efficiency (Φ_F) 0.10–0.99%. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of these PAMs can be determined from cyclic voltammograms as 4.86–5.43 and 3.31–3.34 eV, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4921–4932, 2007     

Vessel Arrival Process and Queueing in Marine Ports Handling Bulk Materials

We study the vessel arrival process in bulk ports handling either cargo containers or minerals. Then we introduce the SHIP/G/1 queue to be able to study the queueing behavior at the port. We present approximations for the asymptotic probabilities of delay and the number of vessels at the port. Numerical examples show the accuracy of the approximations. In appendices, we provide details of the analysis of the number of vessels at the port and the correlation properties of the vessel arrival process.     

On the concept of point value in the infinite-dimensional realization theory

In this article, we study the effect of the chosen representation of a point value (and point evaluation) on the class of periodic signals realizable using a certain type of infinite-dimensional linear system. By suitably representing the point evaluation at the origin in a Hilbert space, we are able to give a complete characterization of its extensions. These extensions involve a new concept called δ-sequence, the use of which as an observation operator of an infinite-dimensional linear system is studied in this article. In particular, we consider their use in the realization of periodic signals. We also investigate how the use of δ-sequences affects the convergence properties of such realizations; we consider the rate and character of convergence and the removal of the Gibbs phenomenon. As still a further demonstration of the significance of the chosen concept of a point value, we discuss the use of distributional point values in the realization of periodic distributions. The possible applications of this work lie in regulator problems of infinite-dimensional control theory, as is indicated by the well-known internal model principle.     

Analysis of a Multiserver Queue with Setup Times

This paper deals with the analysis of an M/M/c queueing system with setup times. This queueing model captures the major characteristics of phenomena occurring in production when the system consists in a set of machines monitored by a single operator. We carry out an extensive analysis of the system including limiting distribution of the system state, waiting time analysis, busy period and maximum queue length. AMS subject classification: 90B22, 60K25     

Applications of electronic speckle interferometry (ESI) techniques for spacecraft structural components

Laser-based electronic speckle interferometry (ESI) techniques, viz., electronic speckle pattern interferometry (ESPI) and electronic speckle shearographic interferometry (ESSI) are used for testing of spacecraft structural components. The combined ESPI and ESSI system developed in house was successfully used for the non-destructive evaluation (NDE) of honeycomb sandwich panels and propellant tanks of Indian Space Research Organization (ISRO). Debonds between face sheet and the honeycomb core were identified using (i) thermal and (ii) dual vacuum stressing methods. On-line NDE of the propellant tanks under internal pressure loading for identification of the minute cracks and thickness reduction areas were successfully implemented by ESI.     

Effect of gamma irradiation with or without hot water dip and transportation from Thailand to Canada on nutritional qualities, ripening index and sensorial characteristics of Thai mangoes (Nahng Glahng Wahn variety)

Two lots of mangoes of the Nahng Glahng Wahn variety from Thailand were irradiated at the Thai Irradiation Center (TIC) at 0.49 to 0.77 kGy. Following this, one batch was retained in Thailand while the other was shipped to the Canadian Irradiation Center (CIC) for investigation of the same variables during storage. This way, it was hoped to compare the effects of gamma radiation with hot water dip (HWI) or without (I) before and after transportation on the ripening, vitamin C and vitamin A content and sensory qualities of mangoes. The results indicate that the I and HWI treatments delayed the ripening of the mangoes. The irradiated groups appeared to have a slightly higher content of ascorbic acid on the first day after irradiation than their corresponding controls. The sensory evaluation indicates that the panelists mostly favoured the I and HWI irradiated groups for the overall appearance and texture of whole mangoes and pulp and in taste and palatability of the pulp alone. Transportation stress did not appear to have much of an effect on the ascorbic acid and dehydroascorbic acid levels and the sensorial tests. The mangoes stored and studied in Canada appeared to have a lower vitamin A content.     

Expert consensus in solo voice performance evaluation

Experts were interviewed to identify criteria for evaluation of vocal performance. A scale was then constructed and inter- and intrajudge reliability assessed. Experts listened to 19 different performances, plus 6 presented a second time. Interjudge reliability for one judge was modest, but increased dramatically as the size of the judge panel increased. The most reliable items were overall score and intonation accuracy. Diction was less reliable than other items. Intrajudge reliability was higher for overall score than for any other item. A factor analysis on the test items yielded factors labelled intrinsic quality, execution, and diction. Another factor analysis, using the experts as variables, revealed two underlying evaluative dimensions. It was found that 13 experts were primarily influenced by execution, and that 8 were mainly affected by intrinsic quality. Interjudge and intrajudge reliabilities of these two groups differed.     

应用马尔科夫状态转移链的作战航空综合体效能评估

文章阐述了作战航空综合体的相关概念及组成,应用马尔科夫状态转移链建立了作战航空综合体完成典型作战任务时的数学模型,确定了作战效能的评估指标,最后通过具体算例检验了模型的正确性和可行性.