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331.
N.N. Kolesnikov E.B. Borisenko D.N. Borisenko V.K. Gartman 《Journal of Crystal Growth》2007,300(2):294-298
GaSe crystals have been grown from melt. There are several reasons why it is difficult to meet ideal demands for nonlinear optic material, GaSe single crystal. First, these crystals have a tendency towards lamination because of great difference in a and c crystal lattice parameters and very weak Vander der Waals forces in c direction. Next, there is a great difference in saturation vapor pressure of the components, which can cause nonstoichiometry of a melt-grown crystal composition. Another obstacle in the growth of perfect GaSe crystals is dendrite formation caused by instability of the growth front. To overcome this obstacle we used Bridgman technique and have found the temperature and pressure conditions, and growth velocity which provide growth of perfect bulk single crystals of about 100 mm in length and 20 mm in diameter. Sharp Laue patterns and a rocking curve confirm perfect structure of the grown crystals. Electron-probe X-ray microanalysis shows stoichiometric composition of GaSe crystals and X-ray phase analysis reveals presence of single-phased hexagonal structure. 相似文献
332.
Startling magnetic effects on the spontaneous polarization echo in some silicate glasses at low and ultralow temperatures have been reported in the last decade or so. Though some progress in search of an explanation has been made by considering the nuclear quadrupole dephasing of tunneling particles, here we show that the effect of a magnetic field can be understood quantitatively by means of a special tunnel mechanism associated with paramagnetic impurities. For the Fe(3+)-, Cr(3+)-, and Nd(3+)-contaminated glasses we provide reasonable fits to the published data as a function of applied magnetic field and temperature. 相似文献
333.
Electrodeposition of silicon from three different ionic liquids: possible influence of the anion on the deposition process 总被引:1,自引:0,他引:1
G. Pulletikurthi A. Lahiri T. Carstens N. Borisenko S. Zein El Abedin F. Endres 《Journal of Solid State Electrochemistry》2013,17(11):2823-2832
The electrodeposition of silicon was investigated from three different ionic liquids with the cation 1-butyl-1-methylpyrrolidinium ([Py1,4]+) and three different anions, namely, trifluoromethylsulfonate (TfO?), bis(trifluoromethylsulfonyl)amide (TFSA?) and tris(pentafluoroethyl)-trifluorophosphate (FAP?) at room temperature and at 100 °C, respectively. The electrodeposition was performed on gold and on copper substrates. Cyclic voltammetry was used to evaluate the possible influence of anions on the deposition process. In situ STM studies were also carried out to examine the interfacial behaviour of the SiCl4/[Py1,4]TFSA and SiCl4/[Py1,4]FAP on Au(111) at room temperature. In situ STM measurements revealed that an underpotential deposition of Si in [Py1,4]FAP occurred on Au (111) at ~ -0.5 V (vs. Fc/Fc+). In comparison, only adsorption of ionic liquid and gold surface reconstruction was found to occur in the potential regime between -0.3 and ?1.8 V (vs. Fc/Fc+), respectively, in the case of [Py1,4]TFSA. In situ STM investigations reveal an effect of the anion on the interfacial processes. In situ I/U tunnelling spectroscopy shows that the band gap of the electrodeposits is ~1.1 eV, indicating that semiconducting silicon has been electrodeposited. Potentiostatic electrolysis was performed to deposit Si from the employed electrolytes at room temperature and at 100 °C. The deposits were characterised using scanning electron microscopy and X-ray diffraction. Thin films of Si could be obtained from the employed ionic liquids and the quality of the deposits was significantly improved at 100 °C. 相似文献
334.
Mass spectrometry of the self-association and complexation of triterpene saponins and cholesterol 总被引:1,自引:0,他引:1
A. V. Lekar’ L. A. Yakovishin E. V. Vetrova M. I. Rudnev N. I. Borisenko 《Journal of Analytical Chemistry》2011,66(13):1276-1280
Electrospray ionization mass spectrometry has been used to study the self-association of α-hederin and hederacoside C (from
Hedera) glycosides. The complexation of glycosides with cholesterol has been considered. It has been revealed that α-hederin
forms self-associates registered in ESI mass spectra, while no self-associates have been found for hederacoside C and cholesterol.
Cholesterol produces molecular complex with α-hederin, while complex formation between cholesterol and bisdesmoside hederacoside
has not been observed. 相似文献
335.
A survey devoted to A0-condensate in gauge theories at high temperature is presented. Both theoretical foundations of the spontaneously generated condensate and known methods of its calculation are discussed. As the most important consequence, the SU (N) global symmetry breakdown is investigated in detail. The influence of A0 on matter fields is studied in different aspects. Some new results concerning this subject are reported as well. 相似文献