N,N-Dibromobenzenesulfonamide as an analytical reagent: Determination of thiocyanate and cyanide ions in metal complexes and salts and thiosemicarbazide alone and in its metal complexes

Simple, rapid, and reproducible analytical procedures, for determining thiocyanate and cyanide ions in metal salts and complexes and thiosemicarbazide (TSC) in the free state and in its metal complexes, with the new oxidant, dibromamine-B (DBB), have been proposed. These procedures are also useful for computing the number of ligands present in the complexes. With DBB, CN⁻, and NCS⁻ ions and TSC undergo stoichiometric oxidations with 2-, 8-, and 12-electron changes per ion or molecule, respectively, in water-acetic acid medium. The reagent DBB has been prepared and characterized by elemental analyses and ir and FT-NMR-¹H and -¹³C spectral data.     

Calculation of the spectral distribution of absorption coefficients in vibrational spectra of complicated molecules,polymers and molecular crystals

The interpretation of vibrational spectra of complicated systems is necessary for the subsequent use of these spectra in the analysis of the structure and physical properties of complicated molecules, polymers and molecular crystals.This interpretation is accomplished with the aid of various methods including calculations of frequencies and in certain cases use of the intensities of absorption bands.     

激励国外直接投资的合资方案

本文讨论在国际经济投资中，国外投资者主观认定的政策风险对国外直接投资的影响，提出东道国激励项目中的国外直接投资达到不受风险影响投资量的合资方案，证明了该方案的存在性，并在不同条件下给出方案的选择方法．讨论了合资方案对合资后双方的利益的影响。     

Bounds on the number of Hamiltonian circuits in the n-cube

New upper and lower bounds are found for the number of Hamiltonian circuits in the graph of the n-cube.     

高校学生思想政治教育实效论

对高校学生思想政治教育实效的涵义、特点、功能、评价原则、指标体系等理论进行研究，目的是为高校学生思想政治教育效果的考核、评估提供科学的依据和原则，这有利于克服长期以来高校学生思想政治教育实效缺乏量的规定性的空洞思想，使高校思想政治教育效果更加显露，从而增强人们对高校思想政治教育重要性的共识．     

网络环境下高校图书馆的信息服务

该文分析了在网络环境下高校图书馆信息服务的特点及影响高校图书馆信息服务创新发 展的制约因素,并针对这些特点及制约因素提出了相应的对策。     

微分反馈控制与延迟微分反馈控制

证明了微分反馈控制洛伦兹系统在三个平衡点S0，S1和S2的可控性，提出了延迟微分反馈控制DDFC，DDFC利用可测变量的微商进行反馈，理论证明DDFC加于洛伦兹系统的第3个方程时3个平衡点均不稳定可控，而加于洛伦兹系统的第2个方程时平衡点S0不可控而平衡点Sl和S2稳定可控，用Matlab进行数值仿真，调节延迟时间τ和控制增益k，DDFC系统能自动寻找和稳定不同的不稳定周期轨道UPO，实现混沌控制。     

On hypohamiltonian graphs

Herz, Duby and Vigué [9] conjectured that every hypohamiltonian graph has girth 5. In the present note hypohamiltonian graphs of girth 3 and 4 are described. Also two conjectures on hypohamiltonian graphs made by Bondy and Chvátal, respectively, are disproved.     

Ketene-S,S,-acetals—VI : Synthesis of 3,3-bis-(methylthio)-2-propene-2-alkyl-1-aryl-1-ones and their reaction with guanidine: A novel route for pyrimidine synthesis

The α-ketoketene-S,S,-acetals 2a–h have been synthesized from the appropriate ketones 1a–f in good yields by extending the established method. The acetals 2a–d react with guanidine in the presence of sodium ethoxide to give pyrimidines 4a–d in 35–59% overall yields (Scheme 1). Treatment of 2e with guanidine similarly gave 5a in 23% yield. However, the reaction of 2e with guanidine in the presence of sodium n-propoxide gave a mixture of three products from which 5a was isolated as major product (20%) with 6a (7%) and 7a (5%). Under similar reaction conditions, 2f gave 5b, 6b and 7b in identical yields. Treatment of 2g–h with guanidine in the presence of sodium n-propoxide gave only 8a (28%) and 8b (23%) respectively. The formation of these pyrimidines involves base induced 1,3-proton migration in 2a–h to give intermediate olefins 10a–h.