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1.
S. A. Klimin M. N. Popova E. P. Chukalina B. Z. Malkin A. R. Zakirov E. Antic-Fidancev Ph. Goldner P. Aschehoug G. Dhalenne 《Physics of the Solid State》2005,47(8):1425-1430
The absorption spectra of Yb2Ti2O7 single crystals and the luminescence and luminescence excitation spectra of Y2Ti2O7: Yb (1%) polycrystals were studied in the temperature range 4.2–300 K. The spectra were analyzed in terms of the crystal-field
theory and the exchange-charge model. Based on the set of crystal-field parameters found for Yb2Ti2O7, analogous sets of parameters were determined for other rare-earth titanates and proved to be in reasonable agreement with
all available experimental data.
__________
Translated from Fizika Tverdogo Tela, Vol. 47, No. 8, 2005, pp. 1376–1380.
Original Russian Text Copyright ? 2005 by Klimin, Popova, Chukalina, Malkin, Zakirov, Antic-Fidancev, Goldner, Aschehoug,
Dhalenne. 相似文献
2.
E. D. Skakovskii S. V. Rykov L. Yu. Tychinskaya Ya. N. Malkin 《Russian Chemical Bulletin》1987,36(8):1753-1755
Conclusions Negative polarization of the protons of aniline and other compounds is observed upon the photoexcitation of aniline solutions. This effect is a consequence of optical nuclear polarization in short-lived donor-acceptor complexes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1890–1892, August, 1987. 相似文献
3.
Light-dependent oxygen uptake was observed and studied in thylakoids from early greening barley in comparison to oxygen uptake in chlorophyll solutions and in thylakoids from fully green leaves. Substantial oxygen uptake was observed in chlorophyll solutions supplemented with tryptophan, histidine, ascorbic acid or linoleic acid. This uptake was diminished by adding azide, beta-carotene and alpha-tocopherol, which are specific singlet-oxygen quenchers. Illuminated thylakoids from greening barley also exhibited marked oxygen uptake that, likewise, was strongly quenched by azide. In comparison, azide was found not to affect oxygen uptake that is associated with the methyl viologen-catalyzed Mehler reaction. It is reasoned that in the first two cases the oxygen uptake arises from chlorophyll-photosensitized activation of oxygen to the singlet state and its consumption by exogenous or endogenous substrates. In greening, we propose that disorganized chlorophyll photo-sensitizes the oxygen uptake. 相似文献
4.
5.
Conclusions The photodissociation quantum yields were determined for a series of phenols in nonpolar media and the increase in quantum yield with increasing excitation energy was shown to be a function of competition of internal intercombinational conversion process.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 438–441, February, 1987. 相似文献
6.
Knaggs S Malkin H Osborn HM Williams NA Yaqoob P 《Organic & biomolecular chemistry》2005,3(21):4002-4010
Two novel tyrosinase mediated drug delivery pathways have been investigated for the selective delivery of cytotoxic units to melanocytes from urea and thiourea prodrugs. The synthesis of these prodrugs is reported, as well as oximetry data that illustrate that the targets are substrates for tyrosinase. The stability of each of the prodrugs in (i) phosphate buffer and (ii) bovine serum is discussed, and the urea prodrugs are identified as lead candidates for further studies. Finally, HPLC studies and preliminary cytotoxicity studies in a melanotic and an amelanotic cell line, that illustrate the feasibility of the approach, are presented. 相似文献
7.
E. V. Ivanova I. A. Malkin V. I. Man'ko 《International Journal of Theoretical Physics》1977,16(7):503-515
In this paper formulas are obtained by means of the coherent-state method for calculating the radiation power of a nonstationary quantum system ofN charged particles whose Hamiltonian is a general quadratic form with respect to coordinates and momenta. The transitions between the coherent states and the Fock states of this system are discussed. The radiation is calculated both in the dipole approximation and strictly. As an example, the radiation of a charge in homogeneous varying electric and magnetic fields is found. The classical limit is considered. 相似文献
8.
9.
It is observed that the classical part of the partition function associated with the mappings from a genus-g Reimann surface Σg to an “almost complex” target space T2d is equal to that related to the mappings Σd to T2g. The classical part related to the mappings from a genus-2g Reimann surface Σ2g described by a “real” period matrix, to a target space Td is equal to the classical part related to mappings from Σ2g to Tg. Some physical consequences of these mathematical identities are discusses. 相似文献
10.
Unusual rheological effects have been revealed during the deformation of polyacrylonitrile (PAN) solutions in DMSO. The effects are observed during the study of rheological properties in a wide range of PAN concentrations and are explained by the structuring occurring at low polymer concentrations. At concentrations of at most 0.1%, the solutions exhibit the behavior of soft gels, which are characterized by yield stresses and frequency-independent storage moduli. As concentration is increased, both effects gradually vanish and the solutions are almost transformed into Newtonian liquids. The results have been explained by the formation of a supramolecular spatial structure at low polymer concentrations. As concentration is increased, the role of structuring is suppressed by the formation of a network of intermacromolecular entanglements. The ability of dilute PAN solutions to exist in two states, i.e., with destroyed structuring and in the form of a physical polymer gel, leads to stress self-oscillations and thixotropic effects. The addition of a precipitant (water) to the PAN-DMSO solutions leads to the formation of a gel throughout the concentration range. 相似文献