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991.
G. Moiseev N. Vatolin B. Štępánek Prof. Dr. J. Šesták 《Journal of Thermal Analysis and Calorimetry》1995,43(2):469-476
A method of calculation of average heat capacities of phase transformation products of complex oxides is suggested. The method takes into account the physical state of products and the increase in the heat capacities of products due to the change of entropy at a phase transformation. Average heat capacities of products formed in a congruous melting of compounds (YCuO2 and Y4Ba3O9), in an incongruous melting of compounds (Y2Cu2O5, BaCuO2, BaCu2O2, Y2BaCuO5, YBa2Cu3O7, YBa2Cu3O6) and in a decomposition in a crystalline state of compounds (Y2BaO4, Y2Ba2O5, Y2Ba4O7, Ba2CuO3, Ba3Cu5O8, YBa2Cu3.5O7.5, YBa2Cu4O8, YBa2Cu5O9) was estimated by using three methods. 相似文献
992.
We establish a condition that guarantees isolation in the space of composition operators acting between Hp(BN) and Hq(BN), for 0 < p ≤ ∞, 0 < q < ∞, and N ≥ 1. This result will allow us, in certain cases where 0 < q < p ≤ ∞, completely to characterize the component structure of this space of operators. 相似文献
993.
Conclusions We have presented the absorption bands associated with f−f and f−d transitions. The investigated ion was placed in the center
of symmetry. For that reason pure electric dipole f−f transitions are forbidden, but thet are allowed for f−d transitions.
Nevertheless, pronounced vibronic transitions were obseved not only in the f−f lines but also for f−d bands. An assignment
of the observed lines supported by previously reported Raman and IR spectra is proposed.
Published in Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 4, pp. 58–62, July–August, 1995. 相似文献
994.
995.
996.
We show that, in the classes of functions with values in a real or complex Banach space, the problem of Hyers-Ulam stability of a linear functional equation of higher order (with constant coefficients) can be reduced to the problem of stability of a first order linear functional equation. As a consequence we prove that (under some weak additional assumptions) the linear equation of higher order, with constant coefficients, is stable in the case where its characteristic equation has no complex roots of module one. We also derive some results concerning solutions of the equation. 相似文献
997.
The unambiguous synthesis of three naturally occurring and biologically active xanthone 1-O and 8-O-β-D -glucosides of 5-O-methyl- and de-O-methylbellidifolin ( 2–4 ) was accomplished. The protected xanthone aglycones having only a single reactive OH group were prepared by selective benzylation, methylation, and debenzoylation reactions. An unexpected stability of the 1-MeO group towards demethylation was observed. 相似文献
998.
Barbara R. Hillery James E. Girard Michele M. Schantz Stephen A. Wise 《Journal of separation science》1995,18(2):89-96
A novel p,p-cyanobiphenyl stationary phase (p-cyanobiphenyl, p-allyloxy methylpolysiloxane) has been evaluated for the GC investigation of polychlorinated biphenyls (PCBs). Several PCB congeners which coelute on the phases typically used for PCB analysis (e.g. 5% phenyl methylpolysiloxane) are separated on the p,p-cyanobiphenyl phase, including the hexachlorobiphenyl congeners PCB 163, PCB 164, and PCB 138. In this work, a p,p-cyanobiphenyl stationary phase was used to measure selected PCB congeners in two Standard Reference Materials (SRMs) available from the National Institute of Standards and Technology (NIST), and two Certified Reference Materials (CRMs) available from the Community Bureau of Reference (BCR). The materials analyzed were SRM 1588, Organics in Cod Liver Oil; SRM 1945, Organics in Whale Blubber; CRM 349, Chlorobiphenyls in Cod Liver Oil; and CRM 350, Chlorobiphenyls in Mackerel Oil. Concentrations are reported for several PCB congeners which coelute on the 5% phenyl methylpolysiloxane, including PCB 163 and PCB 164. 相似文献
999.
The aim of the paper is to describe all open subsets of a projective space with an action of a reductive group which admits
a good quotient. As in the case of Mumford’s geometric invariant theory (which concerns projective good quotients) the problem
can be reduced to the case of an action of a torus. We also show how to distinguish examples of open subsets with a good quotient
coming from Mumford’s theory and give examples of open subsets with non-quasi-projective quotients. 相似文献
1000.
J. Skubiszewska-Zięba R. Leboda B. Charmas W Grzegorczyk R. Szmigielski 《Journal of Thermal Analysis and Calorimetry》2006,86(1):187-194
Thermal analysis was used to study thermal behavior of the sulfonated
ion exchange resin Duolite C20 in the hydrogen, sodium and calcium forms.
The aim of this paper was to prepare spherical carbon adsorbents. SEM and
AFM microscopic methods have been applied to describe their surface characteristics.
It was stated that structural parameters of prepared active carbons depend
on the kind of cation present in the resin. The use of calcium form of Duolite
C20 as the initial polymer precursor allowed to obtain the active carbon with
better yield and better developed pore structure compared with other forms
of this ion exchanger. 相似文献