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991.
J. Siva Kumar U. V. Subba Rao K. V. Satyanarayana Rao K. Narasimha Reddy 《Crystal Research and Technology》1991,26(1):103-108
Thin films of various thicknesses in the MIM structure have been prepared from the the powders of SnO2, Sb2O3 and (SnO2 + Sb2O3) of high purity by the thermal evaporation technique in a vacuum of 10−5 Torr. Dielectric properties of SnO2, Sb2O3, and their mixed thin films have been studied with ac and dc electric fields and frequency. Capacitance and loss tangent are almost independent on dc voltage upto 1.0 V for SnO2, 10.0 V for Sb2O3 and 2.5 V for mixed films. These capacitors become unstable at 1.0 V for SnO2 films and 2.5 V for mixed films. For higher film thicknesses the decay in these films starts at higher voltages. Capacitance and loss tangent increases with applied ac voltage in SnO2, Sb2O3, and their mixed films. A comparison of the capacitance values of SnO2, Sb2O3, and their mixed films showed that the capacitance values are less in Sb2O3 as compared to SnO2 films. In mixed films the capacitance is greater than the constituent films. These studies have shown that Sb2O3 films are found to be more stable compared to SnO2 and their mixed films for ac and dc voltages. The results thus obtained on SnO2, Sb2O3, and their films are presented and discussed. 相似文献
992.
It could be shown that the preparation of sodium A zeolite is possible by the reaction of quartz and γ-Al2O3 with NaOH-solution. The zeolite formation is dependent on the mechanical preliminary treatment of quartz. Only the partially crystalline part of quartz dissolves and reacts with Al2O3 to form zeolite. The grinding of quartz/γ-Al2O3 mixtures can in certain limits raise the zeolite formation but essentially only influences the kinetics of the zeolite formation. 相似文献
993.
D. Klimm P. Hofmann P. Paufler W. Reichelt U. Krbl 《Crystal Research and Technology》1991,26(5):631-637
Damping of ultrasonic waves with frequencies in the 100 kHz region was measured in the temperature region 300 … 1000 K. Two peaks could be observed (near 400 K or near 700 K, respectively). Occurrence of these peaks depends on oxygen content of the sample. The higher temperature peak is attributed to phase transition Pmmm 〈– – –〉 P 4/mmm of YBa2Cu3O7 – x. 相似文献
994.
995.
E. U. Würthwein 《Nachrichten aus der Chemie》1989,37(9):926-927
996.
U. Krell 《Nachrichten aus der Chemie》1989,37(10):1044-1050
997.
We report several combinations of chemical preparation procedures for selective cleaning of InP (100) surfaces in connection with storage procedures. A complex of analytical methods was used to get information about the surface state, the morphology, and the perfection of the surface. Using a standard etch procedure developed by KURTH et al. a post-deoxidation by small concentrated HF or HNO3 is sufficient to get oxide-free, clean InP (100) surfaces even after a storage in methanol for some hours. 相似文献
998.
C12H10N2O2; monoclinic, space group P1 21/c 1 (Z = 2), 826 observed independent reflexions, R = 0.043; lattice dimensions at 25 °C, a = 975.8(3) pm, b = 466.8(1) pm, c = 1186.8(2) pm, β = 108.51(1)°. 相似文献
999.
Chemistry of organic eutectics: Phenanthrene — benzoic acid and phenanthrene — cinnamic acid systems
Solid-liquid equilibrium data for binary systems of phenanthrene with benzoic acid and cinnamic acid, expressed in the form of temperature-composition curves, show the formation of a simple eutectic in each case. Linear velocity of crystallisation (v), studied by capillary method at different undercoolings (ΔT), suggests the applicability of Hillig-Turnbull equation, v = u(ΔT) n, where u and n are constants depending on the nature of solidification. Data on heats of fusion of pure components and eutectics, determined by the DTA method, infer appreciable interaction among the components in the eutectic melts. To highlight the nature of interactions among the components forming the eutectic melt, the excess thermodynamic functions such as hE, sE, and gE were computed. Microscopic studies reveal that the structure of eutectic is different from those of the parent components. Infrared spectra, recorded in the region, 4000 —625 cm−1, indicate weak interactions among the components in the eutectic. 相似文献
1000.
Nonlinear Dynamics - In this article, we present a system of coupled short pulse equations as integrability condition of associated generalized linear eigenvalue problem. We obtain system of... 相似文献