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11.
For ν≥0 let cνk be the k-th positive zero of the cylinder functionC v(t)=J v(t)cosα-Y v(t)sinα, 0≤α>π whereJ ν(t) andY ν(t) denote the Bessel functions of the first and the second kind, respectively. We prove thatC v,k 1+H(x) is convex as a function of ν, ifc νk≥x>0 and ν≥0, whereH(x) is specified in Theorem 1.1. 相似文献
12.
Pyrazoles as molecular probes to study the properties of co-crystals by solid state NMR spectroscopy
Concepción López Rosa M. Claramunt M. Ángeles García José Elguero 《Central European Journal of Chemistry》2004,2(4):660-671
Equimolar mixtures of 3,5-dimethylpyrazole (1) with four NH-imidazoles (2–5) have been studied by13C and 15N CPMAS NMR and by DSC. In three cases, the solid mixture behaves as the sum of the individual components [imidazole (2), 2-methylimidazole (3) and 2,4(5)-dimethylimidazole (5)]. In one case [4,5-dimethylimidazole (4)], the mixture corresponds to a new species in which the dynamic behavior of1 no longer exists. 相似文献
13.
Manuel Urbano Cuadrado Gonzalo Cerruela García Irene Luque Ruiz Miguel Ángel Gómez-Nieto 《Journal of mathematical chemistry》2006,40(1):15-27
A method for the treatment of long-dimensional chemical data arrays is presented in this work with the aim of maximising classification models. The method is based on the construction of fingerprints and the subsequent generation of a similarity matrix. The similarity calculation has been modified through a scaling process to take into account different significance shown by the variables. The method was applied to spectral measurements of wines and several aspects were studied, namely: threshold considered in the construction of fingerprints and patterns, weighting factor used for scaling, normalisation method, etc. The application of both Principal Components Analysis and Soft-Independent Modelling of Class Analogies to the similarity matrices gave better classifications of the information than those obtained using original data. 相似文献
14.
Gonzalo Cerruela García Irene Luque Ruiz Miguel Ángel Gómez-Nieto 《Journal of mathematical chemistry》2006,40(3):213-231
In this paper, we propose a new method for clustering of chemical databases based on the representation of measurements of structural similarity onto multidimensional spaces. The proposed method permits the tuning of the clustering process through the selection of the dimension of the projection space, the normal vectors and the sensibility of the projection process. The structural similarity of each element regarding to the database elements is projected onto the defined spaces generating clusters that represent the characteristics and diversity of the database and whose size and characteristics can be easily adjusted. 相似文献
15.
Raquel F. P. Nogueira Ronaldo A. Pilli Nelson durÁn 《Applied biochemistry and biotechnology》1992,33(3):169-176
Growth of the ascomyceteChrysonilia sitophila during degradation of lignin model dimers and monomers was compared to a glucose control. An inhibition of growth by Cα-carbonyl
monomers and stimulation by β-O-4 lignin model and vanillyl alcohol were observed. A comparison of the degradation by this
ascomycete with the basidiomycetePhanerochaete chrysosoporium showed similarities in relation to the type of degradation caused. 相似文献
16.
Kótai László Horváth Tibor Szentmihályi Klára Keszler Ágnes 《Transition Metal Chemistry》2000,25(3):293-294
We have investigated the effect of temperature on the postulated quasi-intramolecular acid-base reactions in aqueous solutions of Cu(NH3)4(MnO4)2 and Ag(NH3)2ClO4. Pure ammonium permanganate and perchlorate were obtained above 5 C and at room temperature, respectively, due to quasi-intramolecular acid-base reactions. 相似文献
17.
The Ramanujan Journal - This paper provides elementary proofs for several types of congruences involving multipartitions and self-convolutions of the divisor function. Our computations use... 相似文献
18.
Nazarov Anatoly Sztrik János Kvach Anna Tóth Ádám 《Methodology and Computing in Applied Probability》2022,24(3):1503-1518
Methodology and Computing in Applied Probability - This paper deals with a retrial queuing system with a finite number of sources and collision of the customers, where the server is subject to... 相似文献
19.
Klaus Rose Vlastimil MatĚjec Milos Hayer Marie PospiŠilovÁ 《Journal of Sol-Gel Science and Technology》1998,13(1-3):729-733
Various types of UV-curable organically modified siloxanes have been synthesized by the sol-gel method with the aim of fabricating chemically sensitive coatings for silica optical fibers. The refractive index of the coating material can be tailored in the range from 1.46 to 1.56 and sensitivity towards CO2 is achieved by incorporation of amino groups. The interaction of the cured layers with CO2 or with hydrocarbons has been studied in immersion experiments. Both the reaction of CO2 with incorporated amino groups and the penetration of hydrocarbons into the layer induce changes of the light absorption coefficient and the refractive index of the coating which are detected by measuring the output light intensity from the fiber. 相似文献
20.
The stereochemistry of the cyclodehydration of (±)- and meso-2,5-hexanediol on the action of various dehydrating agents was investigated. The earlier assumed and confirmed intramolecular SN2 mechanism for acid-catalysed ring-closure was found to hold in most cases. Various extents of racemisation can be observed on the action of certain Lewis acids, and the solvents concentrated H2SO4 and HMPT (hexamethyl phosporic acid triamide) under previously unexamined reaction conditions. 相似文献