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121.
122.
We investigate the maximum number of edges in a graph with a prescribed number of 1-factors. We also examine the structure of such extremal graphs. 相似文献
123.
A completely inverse AG ??-groupoid is a groupoid satisfying the identities (xy)z=(zy)x, x(yz)=y(xz) and xx ?1=x ?1 x, where x ?1 is a unique inverse of x, that is, x=(xx ?1)x and x ?1=(x ?1 x)x ?1. First we study some fundamental properties of such groupoids. Then we determine certain fundamental congruences on a completely inverse AG ??-groupoid; namely: the maximum idempotent-separating congruence, the least AG-group congruence and the least E-unitary congruence. Finally, we investigate the complete lattice of congruences of a completely inverse AG ??-groupoids. In particular, we describe congruences on completely inverse AG ??-groupoids by their kernel and trace. 相似文献
124.
Dariusz Bochenek Małgorzata Płońska Julian Dudek Zygmunt Surowiak 《Journal of Thermal Analysis and Calorimetry》2010,101(2):623-631
Results of investigations on selected ceramic ferroics and multiferroics by TA method were presented. The authors of the work
used the thermal analysis both to optimize a process of producing the ceramic ferroics and multiferroics and to examine phase
transitions in that type of materials. In the case of synthesis of the ferroics and multiferroics as a result of sintering
of a mixture of simple oxides, the TA method enables to determine the optimum synthesis temperature and temperatures of re-crystallization
and disintegration of compounds and solid solutions. In the case of the sol–gel method, temperatures of dehydratization, burning
of an organic phase, and crystallization of an amorphous powder formed from the residual gel were determined by the TA method.
The TA method was also used to control a process of compacting and sintering the powders at high temperatures (T
s > 1,200 K), thus in a process of ceramic specimen formation. During rapid phase transitions, the ferroelectric specimens
of a first type emit (in the cooling process) or absorb (in the heating process) so called latent heat of the phase transitions.
On the DTA courses, it may be manifested in a form of exo- or endothermic peaks in the Curie temperature area (T
C). The test materials included the ferroelectric ceramics of composition x/65/35 PLZT (ferroic for x < 9 at%) and mixed bismuth oxide layered perovskites (M-BOLP) of composition Bi5TiNbWO15 with <m> = 1.5 and the mutliferroic Pb(Fe1−x
Nb
x
)O3 ceramics (PFN) and Bi5TiFeO15 (BTF). 相似文献
125.
126.
127.
Numan Akdogˇan Sinan Kazan Bekir Aktaş Mustafa Özdemir Hasan İnam Mohamed Obaida Jörg Dudek Kurt Westerholt 《Journal of magnetism and magnetic materials》2011,323(3-4):346-350
Exchange-biased CoO/Fe bilayer grown on MgO (0 0 1) substrate by sputtering, studied by variable angle and temperature ferromagnetic resonance. Room temperature in-plane measurements reveal that the Fe layer was epitaxially grown on MgO substrate with a fourfold cubic symmetry. The data also show that the easy axis of magnetization is in the film plane and makes an angle of 45° with the [1 0 0] crystallographic direction of MgO substrate. The low temperature data exhibit a sudden onset of a field cooling-induced and shifted cubic anisotropy below the Néel temperature of CoO. This results in a twofold uniaxial or fourfold cubic symmetry for in-plane magnetic anisotropy depending on a field cooling direction. Low temperature measurements also present a reduction in the resonance fields due to the antiferromagnetic/ferromagnetic coupling. The developed theoretical model perfectly simulates the experimental data of coupled CoO/Fe bilayer. 相似文献
128.
Microfluidic devices and microsystems have been used to develop blood coagulation monitoring devices for point of care diagnostic use. However, many of them suffer from inherent variability and imprecision, partly due to the fact that they only detect changes in bulk clotting properties and do not reflect the microscopic nature of blood coagulation. This work demonstrates microstructured lateral flow platforms used in combination with fluorescently labelled fibrinogen to detect microscopic clot formation. Plasma samples applied to platforms modified with coagulation activation reagents and fluorescent fibrinogen produced changes in fluorescence intensity due to incorporation of the fluorophore into the forming microclots. It was found that the change in the distribution of the fluorescence within the sample over time was an excellent predictor of the onset of coagulation, which could be used to determine the clotting time. The impact of various assay parameters was optimised and the assay was shown to be capable of measuring the effect of heparin concentration on blood clotting time from 0 to 1.5 U mL(-1). 相似文献
129.
Quasi equilibrated temperature programmed desorption and adsorption (QE-TPDA) of hexane and cyclohexane was applied for characterization of zeolites 5A, ZSM-5, 13X, Y, NaMOR and ordered mesoporous silicas MCM-41, MCM-41/TMB, SBA-15 and HMS. Similar QE-TPDA profiles of hexane and cyclohexane with a single desorption maximum were observed for the wide pore zeolites. No adsorption of cyclohexane for zeolite 5A and a single desorption maximum for ZSM-5 were found, while two-step desorption profiles of hexane were observed for these zeolites. Similar values of the adsorption enthalpy and entropy of hexane and cyclohexane were obtained by fitting the Langmuir model functions for the zeolites X and Y. For NaMOR and ZSM-5 larger differences in these parameters were found. A single desorption peak found at low temperatures in the QE-TPDA profiles of hexane and cyclohexane for the studied silicas was attributed to the multilayered adsorption on their mesopore surface. The adsorption isobars calculated from the thermodesorption profiles were fitted with the BET function. This way values of the specific surface area and the adsorption heat were calculated. Additionally values of the initial heat of adsorption were found by fitting the Henry’s law to the high-temperature sections of the linearized isobars. The largest deviations from the BET and Henry functions and the largest values of the adsorption heats found for SBA-15 indicated the greatest heterogeneity of the adsorption sites on its surface. 相似文献
130.
Lucjan Chmielarz Andrzej Kowalczyk Magdalena Wojciechowska Paweł Boroń Barbara Dudek Marek Michalik 《Chemical Papers》2014,68(9):1219-1227
The intercalation of natural montmorillonite with SiO2, SiO2-Al2O3 or SiO2-TiO2 pillars by the surfactant-directed method resulted in the formation of high surface area porous materials; these were tested as catalytic supports for the process of selective catalytic reduction of NO (DeNOx). The incorporation of titanium or aluminium into the structure of the silica pillars significantly increased the surface acidity of the clay samples. Iron and copper were deposited onto the surface of the pillared clays mainly in the form of monomeric isolated cations and oligomeric metal oxide species. The contribution of the latter species was higher in the clay intercalated with SiO2-TiO2 pillars than in the samples modified with SiO2 and SiO2-Al2O3 pillars. The pillared clay-based catalysts were active in the DeNOx process but, in this group, the best results were obtained for the clay intercalated with SiO2-TiO2 pillars and doped with iron and copper. The catalytic performance of the samples is discussed in respect of their surface acidity and active forms of transition metal species deposited. 相似文献