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111.
Comprehensive studies of X-ray diffraction, oxygen content, superconductivity and Mössbauer effect have been made on FexCu1−xBa2YCu2O7+y superconductors (0.00≤x≤0.70) synthesized by ambient (AM) and high pressure (HP). Results indicate that all the HP-samples have tetragonal structure, smaller lattice parameter c and unit-cell volume than the AM-samples. The studies of oxygen content, and Mössbauer spectroscopy indicate that the HP-samples have higher oxygen content, carrier concentration and average valence of Fe than the AM-samples. Moreover, for the HP-samples more Fe atoms located in CuOx chains have fivefold-oxygen coordination. These are important reasons for the enhancement of Tc in the HP-samples. 相似文献
112.
本文对一类具有对称轴的图A_n(n≥0),得到了它的特征多项式及匹配多项式的精确表达式;同时还得到A_(?)的完美匹配数。 相似文献
113.
I. A. Uspenskaya Z. S. Vakhovskaya M. M. Efremova M. L. Kovba A. L. Emelina Zh. V. Dobrokhotova Yu. V. Goryushkina L. A. Tiflova A. A. Popova A. S. Monaenkova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(4):529-534
The thermodynamic properties of the Ln2BaO4 phases (Ln = Dy, Ho, Sm) were studied by the electromotive force method with a fluoride electrolyte (890–1180 K), solution calorimetry in 1.07 N hydrochloric acid at 298.15 K, and differential scanning calorimetry (298–860 K). The experimental data were jointly processed, and the thermodynamic functions of the compounds over the temperature range 298–1200 K were calculated. 相似文献
114.
Mo2Ni3Si/NiSi metal silicide composite coatings with a fine microstructure consisting of Mo2Ni3Si primary dendrites and the interdendritic Mo2Ni3Si/NiSi eutectics were fabricated on austenitic stainless steel AISI 321 by laser cladding process. Small amplitude reciprocating sliding wear resistance of the coatings is evaluated as functions of normal load and slip amplitude and the wear mechanisms were discussed based on worn surface morphology observations. Results showed that the Mo2Ni3Si/NiSi coatings have excellent small amplitude reciprocating sliding wear resistance. 相似文献
115.
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117.
Z. Karaoglanov 《Fresenius' Journal of Analytical Chemistry》1941,121(5-6):190-209
Ohne Zusammenfassung 相似文献
118.
Stabilized hybrid finite element methods based on the combination of saddle point principles of elasticity problems 总被引:2,自引:0,他引:2
Tianxiao Zhou. 《Mathematics of Computation》2003,72(244):1655-1673
How, in a discretized model, to utilize the duality and complementarity of two saddle point variational principles is considered in the paper. A homology family of optimality conditions, different from the conventional saddle point conditions of the domain-decomposed Hellinger-Reissner principle, is derived to enhance stability of hybrid finite element schemes. Based on this, a stabilized hybrid method is presented by associating element-interior displacement with an element-boundary one in a nonconforming manner. In addition, energy compatibility of strain-enriched displacements with respect to stress terms is introduced to circumvent Poisson-locking.
119.
A. Sanusi M. Z. A. Yahya S. Navaratnam W. J. Basirun Y. Alias N. S. Mohamed A. K. Arof 《Ionics》2003,9(3-4):253-257
In this study, lead sulphide (PbS) was prepared by the chemical bath deposition technique. The sample was characterized by
X-ray diffraction (XRD), Energy Dispersive Analysis of X-rays (EDAX) and cyclic voltammetry. EDAX spectrum shows peaks attributable
to lead and sulphur. The EDAX analysis also shows that the prepared sample is stoichiometric. Cyclic voltammetry experiments
were recorded at 100 mV·s−1 and 400 mV·s−1 scan rates. Results show that the rate controlling electrochemical reaction is electron transfer. The presence of redox waves
shows that the lithium intercalation and deintercalation can occur as a result of lattice expansion in PbS. There were no
differences in the PbS XRD data before and after the cyclic voltammetry experiments indicating that the PbS structure is not
modified upon lithium ion intercalation and deintercalation in PbS. The discharge characteristics for 35 cycles of the cell
using the LiCoO2/PbS couple is presented indicating the possible development of such materials as anode in lithium ion cells. 相似文献
120.
Generation of UV laser light by stimulated Raman scattering in D2, D2/Ar and D2/He using a pulsed Nd:YAG laser at 355nm 下载免费PDF全文
A pulsed Nd:YAG laser at 355nm is used to pump Raman cell filled with D_2, D_2/Ar and D_2/He. With adequately adjusted parameters, the maximum photon conversion efficiency of the first-order Stokes light (S_1, 396.796nm) reaches 33.33% in D_2/Ar and the stability of S_1 in pure D_2 is fairly high, the energy drift being less than 10% when the pump energy drifts in the range of 5%. The conversion efficiency and stability, which are functions of the composition and pressure of the Raman medium and the energy of pump laser, are investigated. The result has been used to optimize the laser transmitter system for a differential absorption lidar system to measure NO_2 concentration profiles. 相似文献