Ditertiary phosphine complexes of (ν-allyl)dicarbonylmolybdenum(II) and -tungsten(II)

Compounds of the type [XM(CO)₂(ν-allyl)L₂] (where X = Cl and Br; M = Mo and W; L₂ = Ph₂PCH₂PPh₂ and Ph₂ PCH₂CH₂PPh₂) have been prepard from the corersponding MeCN complexes. The spectral properties of these compounds and the effects of chelate rign size on ³¹P coordination shifts and J(¹⁸³W—³¹P) have been investigated.     

Preparation,Characterization of Ternary Europium Complex-Doped Thin Sol-Gel Hybrid Film by Fluorescence Spectroscopy

ernary europium complex with dibenzoylmethane(DBM), 1,10-phenanthroline(phen) was in-situ syn thesized in thin SiO₂/polyvinyl butyral(PVB) hybrid films by a two-step sol-gel process, characterized by means of fluorescence spectroscopy. The luminescence spectra, fluorescence lifetimes, photostability were all investigated. The results showed that the hybrid films exhibited the characteristic emission bands of the central rare earth Eu³⁺. In addition, Eu³⁺ presented longer fluorescence lifetime than in an ethanol solution, the complex had a higher photostability in the hybrid film than in the PVB film containing the corresponding pure complex.     

Syn thesis,Characterization of 1,3-Diisopropoxyaloxanes,Their Modification on Calcium Carbonate Filler

Five 1,3-diisopropoxyaloxanes, i. e., (PrⁱO)RO₂AlOAlO₂R(OPrⁱ) [where R=C₁₆H₃₁(Ⅰ)_C₁₈H₃₅(Ⅱ), _C₉H₁₆CH=CHC₇H₁₅(Ⅲ), _P(OCH₂(C₂H₅)CHC₄H₉)₂(Ⅳ), and _C₁₂H₂₃(Ⅴ), respectively] were syn thesized by the hydrolysiscondensation of aluminium isopropoxide with water, exchange reaction with relevant acids. They were characterized by elemental analysis, determination of molecular weight, IR,, ²⁷Al NMR. The results show that the coordination number of Al atom in the compounds is 5, they exist in monomers in benzene. The analyses of TG/DTG, DTA indicated that both the thermal hydrolysis stability, thermal stability of these compounds are in the following order:Ⅰ<Ⅱ<Ⅲ<Ⅳ. The viscosity determinations of light calcium carbonate(L-CaCO₃)/liquid paraffin suspension systems demonstrated that they had an excellent modification effect on the surface of LCaCO₃ filler, the amount needed to form a monomolecular film on the surface of LCaCO₃ particles is in the order:Ⅰ<Ⅱ<Ⅲ<Ⅳ.     

The minimum degree of recursively representable choice functions

We show that the minimum degree of Turing complexity of a recursively representable choice function is Õ″, the degree of a complete ∑₂ set in the Kleene-Mostowski hierarchy. A consequence of this result is that the complexity of such choice functions in this sense is bounded strictly above the degrees of R.E. subsets on $\text{N}$.     

Polynomial differential equations compute all real computable functions on computable compact intervals

In the last decade, there have been several attempts to understand the relations between the many models of analog computation. Unfortunately, most models are not equivalent. Euler's Gamma function, which is computable according to computable analysis, but that cannot be generated by Shannon's General Purpose Analog Computer (GPAC), has often been used to argue that the GPAC is less powerful than digital computation. However, when computability with GPACs is not restricted to real-time generation of functions, it has been shown recently that Gamma becomes computable by a GPAC. Here we extend this result by showing that, in an appropriate framework, the GPAC and computable analysis are actually equivalent from the computability point of view, at least in compact intervals. Since GPACs are equivalent to systems of polynomial differential equations then we show that all real computable functions over compact intervals can be defined by such models.     

Graduation of electron spectrometer intensity scale. Part 1. A theoretical approach

We consider an ordinary spectrometer equipped with a dispersing field analyser (e.g. cylindrical mirror analyser (CMA)), an electron multiplier, and analogue differentiation facilities. Transformation of the true energy distribution of secondary electrons to the spectrometer output voltage is described mathematically using a spectrometer operator. Conditions are established that allow the mathematical expression of the operator to be reduced to a graduation function G(E′) of pass energy E′. The G(E′) function is defined as the product of a probability function definite integral and a multiplier gain coefficient. The operator and/or the graduation function take account of influences of any extraneous fields on the spectrometer output voltage.     

创新创业环境下本科生毕业论文指导的探索与体会

国家推动创新创业的时代大背景,对本科生毕业论文指导提出了比以往更高的期盼。论述了针对本科生毕业论文指导的7个方面的积极探索,以解决本科学生缺乏创新、动手能力差、分析能力欠缺、课本知识不会用、协同能力弱等问题。     

多元统计分析在本科毕业论文指导满意度研究中的应用

毕业论文指导水平是影响毕业论文水平的重要因素,本文根据实际满意度调查的数据,利用主成份分析方法,对毕业论文指导满意度的影响因素进行了实证分析,得出是影响毕业论文指导质量的主要因素,同时,根据实证研究结论,就提高毕业论文指导满意度提出了若干建议.     

Synthesis of 5,7-Dimethyl-2-(5-Substituted-1,3,4-Oxadiazole-2-yl)- Methylenethio-1,2,4-Triazolo[1,5-a]Pyrimidines as Potential Fungicides

New challenging problems in plant protection technology have promoted research to discover more efficient pesticides. In recent years, many chemists have paid much attention to compounds bearing 1,2,4-triazolo [1,5-a] pyrimidine rings due to their broad spectrum of biological activities such as herbicidal and fungicidal effects1-7. Up to now, a great variety of these kinds of compounds have been synthesized, among which some commercially herbicides have been developed including metosulam, f…     

Graduation of electron spectrometer intensity scale. Part 2. How to do it

Graduation function G(E′) absolute values have been determined experimentally for the first time for the intensity scale of an ordinary Auger electron spectrometer. The determination of G(E′) includes creation of an original standard signal and measurement of the consequent reaction of the spectrometer using a “giant rectangular modulation” operation mode, integration of the measurand, and use of an original G(E′) definition. The experimental values of G(E′) are presented in the correct dimensional units for a pass energy range E′ = 150–1000 eV. A non-monotonous behaviour of G(E′), a strong dependence of G(E′) on the multiplier entrance bias voltage, and a discrepancy between the graduation functions of spectrometers of the same type with CMA are demonstrated. Possibilities are predicted for a similar G(E′) determination for other types of spectromer.