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1.
2.
Sufficient conditions which guarantee that certain linear integro-differential equation cannot have a positive solution are
established. 相似文献
3.
Rafael Caballero Mercedes González Flor M Guerrero Julián Molina Concepción Paralera 《European Journal of Operational Research》2007
In this work we present a multiobjective location routing problem and solve it with a multiobjective metaheuristic procedure. In this type of problem, we have to locate some plants within a set of possible locations to meet the demands of a number of clients with multiple objectives. This type of model is used to solve a problem with real data in the region of Andalusia (Spain). Thus, we study the location of two incineration plants for the disposal of solid animal waste from some preestablished locations in Andalusia, and design the routes to serve the different slaughterhouses in this region. This must be done while taking into account certain economic objectives (start-up, maintenance, and transport costs) and social objectives (social rejection by towns on the truck routes, maximum risk as an equity criterion, and the negative implications for towns close to the plant). 相似文献
4.
M. Alves Da Silva M. Helena Gil A. P. Piedade J. S. Redinha A. M. Oliveira Brett J. M. Caridade Costa 《Journal of polymer science. Part A, Polymer chemistry》1991,29(2):269-274
The immobilization of catalase on grafted membranes of poly(ethylene)-g-co-acrylic acid and poly(tetrafluoroethylene)-g-co-acrylic acid and their application in hydrogen peroxide electrochemical sensors is described. The introduction of carboxylic acid groups onto a hydrophobic support provides a good environment for subsequent enzyme immobilization. This single membrane, hydrogen peroxide sensor showed significant improvement with respect to the double membrane versions. The response is very rapid, the linear range being from 10 μM up to 6 mM, with a detection limit of 4.7 μM, and a lifetime of more than 4 months. 相似文献
5.
Inequalities of Nikolski
(Trudy Mat. Inst. Steklova 38 (1951), 2.3, p. 255) in L2πp, p 1, and of Oswald (Izv. Vyssh. Uchebn. Zaved. Mat. 7 (1976), (3.4), p. 71; Theorem 1, p. 69), 0 < p < 1, are extended to the case of Orlicz spaces L2π. 相似文献
6.
JiŘí Kvapil Josef Kvapil Bohumil Perner Michal Košelja Helena Jelínková 《Czechoslovak Journal of Physics》1990,40(11):1283-1287
The methods of growing YAG:Nd crystals with a flat interface and YAP:Nd crystals with a sharp conical interface are described. The form of the interface was controlled by the He and H2O content in the reducing atmosphere composed mainly of Ar and H2 as well as by axial temperature gradient above the melt level. The crystals of 120–180 mm in length were machined to the high-quality slabs. 相似文献
7.
V. Berbenni G. Flor A. Marini V. Massarotti R. Riccardi 《Journal of Thermal Analysis and Calorimetry》1988,34(2):457-463
The energetics of the dehydration reaction of single crystal (Na, Na 50%-Li, Li) and ceramic Na beta-aluminas have been studied.From the dependence of the dehydration enthalpy values on the water content it has been deduced that lattice water can be bound in two different ways i.e. by ion-dipole interactions with conducting cations and by hydrogen bonds with spinel block oxygens. As expected, the first one gives binding energies depending on the nature of the monovalent cation (H=84.5 and 59.4 kJ/mol H2O for Li and Na beta-alumina respectively). In contrast, the enthalpy change associated with the second one is identical for the three beta-aluminas (H=15.1 kJ/mol H2O). The ceramic Na beta-alumina undergoes a surface reaction too (with CO2) leading to the formation of carbonates and bicarbonates.
Zusammenfassung Die Energetik der Dehydratisierungsreaktion von Einkristallen von Na-, Na (50%)/Li- und Li- sowie von Na--Aluminiumoxid wurde untersucht. Aus der Abhängigkeit der Dehydratisierungsenthalpie vom Wassergehalt ergibt sich, daß Wasser auf zwei verschiedene Weisen gebunden ist, nämlich durch Ion-Dipol-Wechselwirkung mit leitenden Kationen und durch Wasserstoffbrückenbindungen mit Sauerstoffatomen. Wie zu erwarten war werden für die ersteren von der Natur der einwertigen Kationen abhängige Bindungsenergien (H=84.1 kJ/Mol H2O bzw. 59.4 kJ/Mol H2O für Li- bzw. Na--Alumina) erhalten. Die auf die zweite Wechselwirkung zurückzuführenden Enthalpieänderung ist dagegen für die drei-Aluminiumoxide identisch (H=15.1 kJ/Mol H2O). Das keramische Na--Aluminiumoxid zeigt auch eine Oberflächenreaktion mit CO2, die zur Bildung von Carbonaten und Bicarbonaten führt.
(Na, Na 50%-Li, Li)- -- . , - . , Li — Na-- , , 84.5 59.4 / 2. , - 15.1 / 2. Na- , .相似文献
8.
Georgi E. Chernev Bisserka I. Samuneva Petar R. Djambaski Isabel M. M. Salvado Helena V. Fernandes 《Central European Journal of Chemistry》2006,4(1):81-91
In this work we present experimental results about the formation, properties and structure of sol — gel silica based biocomposite
containing Calcium alginate as an organic compound. Two different types of silicon precursors have been used in the synthesis:
tetramethylortosilicate (TMOS) and ethyltrimethoxysilane (ETMS). The samples have been prepared at room temperature. The hybrids
have been synthesized by replacing different quantitis of the inorganic precursor with alginate. The structure of the obtained
hybrid materials has been studied by XRD, IR Spectroscopy, EDS, BET and AFM. The results proved that all samples are amorphous
possessing a surface area from 70 to 290 m2/g. It has also been established by FT IR spectra that the hybrids containing TMOS display Van der Walls and Hydrogen bonding
or electrostatic interactions between the organic and inorganic components. Strong chemical bonds between the inorganic and
organic components in the samples with ETMS are present. A self-organized nanostructure has been observed by AFM. In the obtained
hybrids the nanobuilding blocks average in size at about 8–14 nm for the particles. 相似文献
9.
Summary Electron microscope examination of thixotropic aluminium and thorium molybdate gels shows that one hour after formation they are constituted by short fibrils of small axial ratio. The fibrils of the aluminium molybdate gels, with ageing at room temperature or with boiling, increase in diameter and length; the fibrous shape of the particles is maintained after two and a half years of ageing; all fibrils are crystalline by electron diffraction. The fibrils of the thorium molybdate gels, except in the gels containing hydrochloric acid, change with ageing at room temperature or with boiling, into plates of hexagonal, elliptical or rectangular profile; the fibrils and plates are crystalline and have the same electron diffraction pattern as the fibrils.This work was aided, in part, by grants from Conselho Nacional de Pesquisas and the Rockefeller Foundation. 相似文献
10.
The new Pd(II), Pt(II), Re(V), Mo(VI) and W(VI) complexes of 2-hydroxynicotinic acid (H2nicO), trans-[PdCl(HnicO)(PPh3)2]·0.75CH3CN (1), K[PdCl(HnicO)2]·H2O (2), [Pd(HnicO)2(bipy)] (3), cis-[PtCl(HnicO)(PPh3)2]·0.75CH3OH·0.5H2O (4), [PtCl(HnicO)(bipy)] (5), cis-[ReOI2(HnicO)(PPh3)] (6), Na2[Mo2O6(HnicO)2]·5H2O (7), Na2[Mo4O12(HnicO)2]·2H2O (8) and Na2[W2O6(HnicO)2]·5H2O (9) have been prepared. The crystal structures of 1 and 4, were determined by X-ray diffraction and show the HnicO− ligand coordinated to palladium or platinum through the nitrogen atom only. Infrared, Raman, 1H and 13C{1H} NMR spectroscopic data for the complexes are presented and are in agreement with the crystallographic results. 相似文献