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21.
Zaharescu M. Jitianu A. Brăileanu A. Madarász J. Novák CS. Pokol G. 《Journal of Thermal Analysis and Calorimetry》2003,71(2):421-428
Hybrid materials with different amounts of organics permanently bound on the inorganic network obtained in the TEOS-MTEOS
(tetraethoxysilan-methyltriethoxysilan) system are used for obtaining coatings with different optical and mechanical properties.
To study the thermal stability of the mentioned materials, compositions with different molar ratios of the precursors were
prepared. The influence of the solvent and water amounts on the gelation process was also investigated. The gels obtained
were characterised by IR spectrometry and their decomposition temperatures were determined by DTA/TG. Thermal stability of
the gels is rather influenced by their composition than the conditions of the gelation process.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
22.
It is well known how the Kostant-Rowen Theorem extends the validity of the famous Amitsur-Levitzki identity to skew-symmetric matrices. Here we give a general method, based on a graph theoretic approach, for deriving extensions of known permanental-type identities to skew-symmetric and symmetric matrices over a commutative ring of prime characteristic. Our main result has a typical Kostant-Rowen flavour: IfM≥p[n+1/2] then $C_M (X,Y) = \sum\limits_{\alpha ,\beta \in Sym(M)} {x_{\alpha (1)} y_{\beta (1)} x_{\alpha (2)} y_{\beta (2)} } ...x_{\alpha (M)} y_{\beta (M)} = 0$ is an identity onM n ? (Ω), the set ofnxn skew-symmetric matrices over a commutative ring Ω withp1Ω=0 (provided that $P > \sqrt {[n + 1/2)} $ ). Otherwise, the stronger conditionM≥pn implies thatC M(X,Y)=0 is an identity on the full matrix ringM n(Ω). 相似文献
23.
R. Sz. Madarász 《Algebra Universalis》1995,34(2):179-184
Chris Brink, in his paper,Power Structures, describes the construction ofgeneralized quotient algebras. IfA is any algebra, the corresponding generalized quotient algebraA/R is defined for every value-preserving relation
. As we will see in the present paper, in order to make the corresponding operations on the setA/R well-defined, it is not enough forR to be value-preserving. The only redundancy in the definition of the usual quotient algebra is symmetry.Presented by G. Grätzer. 相似文献
24.
57Fe Mössbauer study of amorphous and nanocrystalline Fe73.5Nb3Cu1Si13.5B9 after neutron irradiation
57Fe Mössbauer spectroscopy is used to study neutron irradiation induced changes in the short-range order of Fe73.5Nb3Cu1Si13.5B9 alloy. The samples are investigated in both amorphous and nanocrystalline states. Neutron irradiation leads to an increase of the standard deviation of a hyperfine field distribution (HFD), implying rearrangement of the atoms towards disordering. Simultaneously, changes in the average value of the hyperfine field and a net magnetic moment position occur as a consequence of a spin reorientation, atom mixing and microscopic stress centres which are introduced by neutron irradiation. 相似文献
25.
K. Mészáros Szécsényi K. Tomor G. Pokol 《Journal of Thermal Analysis and Calorimetry》1994,41(1):125-134
The phase diagram for the AgNO3?KNO3 system has been determined using differential scanning calorimetry (DSC). Eutectic point has been found at 391 K andX Ag=0.580 mole fraction AgNO3. The DSC curves indicate the existence of an intermermediate compound (AgNO3·KNO3) in the KNO3-rich region of the phase diagram. This compound was identified in the solid phase by X-ray diffraction. The melting and the crystallization processes were followed with the aid of a hot stage microscope, too. 相似文献
26.
Prof. Dr. B. Korte Prof. Dr. L. Lovász 《Mathematical Methods of Operations Research》1985,29(7):249-267
In previous papers many different classes and constructions of greedoids have been defined and studied. This paper documents inclusion relations among all subclasses of greedoids which are known so far. It will be shown that all inclusion relations are proper and that all but one subclasses of interval greedoids are distinct.
Supported by the joint research project Algorithmic Aspects of Combinatorial Optimization of the Hungarian Academy of Sciences (Magyar Tudományos Akadémia) and the German Research Association (Deutsche Forschungsgemeinschaft, SFB 21). Part of this research was done while the first author was visiting the Department of Combinatorics and Optimization, University of Waterloo. 相似文献
Zusammenfassung In früheren Arbeiten wurden viele verschiedene Klassen und Konstruktionen für Greedoide eingeführt und studiert. In dieser Arbeit werden alle bekannten Inklusionsbeziehungen zwischen Unterklassen von Greedoiden dokumentiert. Es wird gezeigt, daß alle Inklusionsbeziehungen echt und alle Unterklassen mit einer Ausnahme tatsächlich verschieden sind.
Supported by the joint research project Algorithmic Aspects of Combinatorial Optimization of the Hungarian Academy of Sciences (Magyar Tudományos Akadémia) and the German Research Association (Deutsche Forschungsgemeinschaft, SFB 21). Part of this research was done while the first author was visiting the Department of Combinatorics and Optimization, University of Waterloo. 相似文献
27.
Gy. Marosi R. Lágner Gy. Bertalan P. Anna A. Tohl 《Journal of Thermal Analysis and Calorimetry》1996,47(4):1155-1161
Nucleating and transcrystallization behaviour of additives in engineering PP composites and the effect of modified interfacial structure is the subject of this series of papers. The first part concentrates on polypropylene/liquid crystalline polyester blends. Increased crystallisation temperature and degree of crystallinity of polypropylene is characteristic to the blends containing different amount of LCP additive. Transcrystallization process governs the formation of crystalline structure in these systems in course of isothermal crystallisation at 132C. The nucleating effect of LCP gives rise to more uniform crystalline structure in the polypropylene phase.The financial support of the OTKA 014194 is acknowledged with gratitude. 相似文献
28.
I. Halász H. O. Gerlach A. Kroneisen und P. Walkling 《Fresenius' Journal of Analytical Chemistry》1968,234(2):97-108
Zusammenfassung Die Bandenverbreiterung in der Flüssigkeits-Chromatographie, verursacht durch Kolonne, Kolonnenzuleitungen und Detektor, wurde untersucht durch Messung von h-u-Kurven bis zu Kolonneneingangsdrucken von 15 at. Die Einflüsse außerhalb der Kolonne konnten durch eine besondere Formgebung der entsprechenden Bauelemente vermindert werden. Aromatische N-Verbindungen wurden an einer Silicagel-Kolonne getrennt, wobei etwa 1 effektiver Boden pro Sekunde erzielt werden konnte.
Symbolverzeichnis at 1 Kilopond/cm2 Druck - h Bandenverbreiterung in der Kolonne oder HETP [cm] - h exp L(w/4t R)2 = experimentell bestimmte h-Werte - k Verteilungskoeffizient [-] - k = t R/t0 Massenverteilungsverhältnis [-] - t 0 Durchbruchszeit der Inertbande [sec] - t R Retentionszeit [sec] - t R t r-t0 = Reduzierte Retentionszeit [sec] - u Lineare Geschwindigkeit der mobilen Phase [cm · sec–1] - w Bandenbreite, Achsenschnitt der Wendetangenten an der Basislinie [sec] - C Massentransportkoeffizient der van Deemter-Gleichung [sec] - L Länge der Kolonne [cm] - N (4t R/w)2 = effektive Bandenschärfe oder effektive Bodenzahl - V m Volumen der mobilen Phase in der Kolonne [cm3] - V s Volumen der stationären Phase in der Kolonne [cm3] Die Autoren bedanken sich bei der Deutschen Forschungsgemeinschaft, Bad Godesberg, mit deren finanzieller Unterstützung diese Arbeit ausgeführt wurde. 相似文献
Summary Peak broadening effects in liquid chromatography inside and outside the column, i.e. the influence of the column, the connection and the detector were studied, determining experimentaly h vs. u curves up to 15 at. inlet pressure. Geometry for both of the latter is proposed to diminish peak broadening outside the column. Aromatic N-compounds are resolved on silicagel producing about 1 effective plate per second.
Symbolverzeichnis at 1 Kilopond/cm2 Druck - h Bandenverbreiterung in der Kolonne oder HETP [cm] - h exp L(w/4t R)2 = experimentell bestimmte h-Werte - k Verteilungskoeffizient [-] - k = t R/t0 Massenverteilungsverhältnis [-] - t 0 Durchbruchszeit der Inertbande [sec] - t R Retentionszeit [sec] - t R t r-t0 = Reduzierte Retentionszeit [sec] - u Lineare Geschwindigkeit der mobilen Phase [cm · sec–1] - w Bandenbreite, Achsenschnitt der Wendetangenten an der Basislinie [sec] - C Massentransportkoeffizient der van Deemter-Gleichung [sec] - L Länge der Kolonne [cm] - N (4t R/w)2 = effektive Bandenschärfe oder effektive Bodenzahl - V m Volumen der mobilen Phase in der Kolonne [cm3] - V s Volumen der stationären Phase in der Kolonne [cm3] Die Autoren bedanken sich bei der Deutschen Forschungsgemeinschaft, Bad Godesberg, mit deren finanzieller Unterstützung diese Arbeit ausgeführt wurde. 相似文献
29.
Assignment of Saharan dust sources to episodes in Hungarian atmosphere by PIXE and TOMS observations
E. Koltay I. Borbély-Kiss Zs. Kertész Á. Z. Kiss Gy. Szabó 《Journal of Radioanalytical and Nuclear Chemistry》2006,267(2):449-459
Summary Thirty-seven episodes of dust intrusion were observed between February 12, 1991 and August 31, 2000 in the Hungarian atmosphere
and found to be of Saharan origin. They have been assigned to typical source areas in Northern Africa selected by systematic
investigations related to the Mediterranean Basin. Elemental concentrations and regional signatures deduced from PIXE analysis,
total suspended particle mass, and black carbon mass have been measured on dust samples collected in Debrecen, Hungary. These
data combined with Aerosol Index data, and dust plume axes obtained from TOMS data from NASA satellites were used for assigning
the most probable source areas of the dust transported to the sampling site. Our data and conclusions are in accordance with
other published investigations on the predominant role of Saharan dust emission in building up the aerosol load of the global
atmosphere. 相似文献
30.
Two methods are developed, when solving the related time-independent Schrodinger equation (TISE), to cope with the singular terms of the vibrational kinetic energy operator of a triatomic molecule given in orthogonal internal coordinates. The first method provides a mathematically correct treatment of all singular terms. The vibrational eigenfunctions are approximated by linear combinations of functions of a three-dimensional nondirect-product basis, where basis functions are formed by coupling Bessel-DVR functions, where DVR stands for discrete variable representation, depending on distance-type coordinates and Legendre polynomials depending on angle bending. In the second method one of the singular terms related to a distance-type coordinate, deemed to be unimportant for spectroscopic applications, is given no special treatment. Here the basis set is obtained by taking the direct product of a one-dimensional DVR basis with a two-dimensional nondirect-product basis, the latter formed by coupling Bessel-DVR functions and Legendre polynomials. With the basis functions defined, matrix representations of the TISE are set up and solved numerically to obtain the vibrational energy levels of H3+. The numerical calculations show that the first method treating all singularities is computationally inefficient, while the second method treating properly only the singularities having physical importance is quite efficient. 相似文献