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排序方式: 共有715条查询结果,搜索用时 31 毫秒
691.
Mikhail I. Solonin Yuri K. Bibilashvili Nikolai B. Sokolov Albert K. Panyushkin Vladimir Tsibulia Oleg B. Samoylov Vadim B. Kurilev Vladimir S. Kuul Vladimir S. Kuul Viktor B. Kaidalov Rudolf A. Peskov Valentin F. Ershov 《Nuclear Engineering and Design》1997,173(1-3)
An alternative design of fuel assembly has been developed for the WWER-1000 reactor with the aim of assuring a geometrical stability of the core during operation. The fuel assembly provides enhanced safety and substantial improvement in the WWER-1000 fuel cycle economics. 相似文献
692.
693.
694.
Kuibyshev. Translated from Fizika Goreniya i Vzryva, Vol. 25, No. 1, pp. 64–68, January–February, 1989. 相似文献
695.
696.
The clinical effectiveness of alvesin, a mixture of pure amino acids, balanced by the amino acid composition, was studied in the treatment of patients with chronic diseases of the small intestine. The drug was well tolerated by the patients after its parenteral administration. A high clinical effect of alvesin was recorded in 98 patients suffering from chronic enteritis, celiac disease, general variable immunodeficiency. The optimal dose of the drug was determined. 相似文献
697.
Nikolai G. Dorbakov Vadim V. Grebenev Vladimir V. Titkov Evgeniya S. Zhukovskaya Sergey Y. Stefanovich Oksana V. Baryshnikova Dina V. Deyneko Vladimir A. Morozov Alexei A. Belik Bogdan I. Lazoryak 《Journal of the American Ceramic Society》2018,101(9):4011-4022
Solid solution of Ca9‐xMgxBi(VO4)7 in powder and ceramic forms are obtained by solid‐state reactions. Details of their crystal structures are determined for x = 0.25 and x = 0.5 by synchrotron radiation diffraction and the Rietveld method. The refinement has confirmed that Mg2+ is replacing Ca2+ in M5 position of a polar (S.G. R3c) β‐Ca3(PO4)2‐type structure. Thermal analysis, dielectric and second harmonic generation experiments in broad temperature regions have proved this polar structure is formed for 0 ≤ x ≤ 0.7. Magnesium for calcium substitution enhances optical nonlinear activity of Ca9‐xMgxBi(VO4)7 in 0 < x ≤ 0.5. Two phase transitions have been found, one of which from polar to centrosymmetric phase is accompanied by dielectric constant peak of ferroelectric type. The other is upper on temperature, marked with smaller dielectric anomaly, and goes between 2 centrosymmetric phases. Temperatures of the phase transition only slightly depend on x, the first being near 1050 K, the second near 1100 K. Electric conductivity quickly rises with temperature in the polar phase. At higher temperature it changes according to the Arrhenius law with small activation energy, Ea ~ 0.7 eV for bulk conductivity and Egb ~ 2.0‐2.5 eV for grain boundary conductivity. The analysis of bulk and grain boundary conductivities agrees with Ca2+‐ion fast transport in ceramics. The bulk conductivity slowly decreases with magnesium content, the grain boundary conductivity does not notably depend on the composition. 相似文献
698.
Burdock (Arcticum lappa L.) roots are used in folk medicine and also as a vegetable in Asian countries especially Japan, Korea, and Thailand. We have used LC-MS(n) (n = 2-4) to detect and characterize in burdock roots 15 quantitatively minor fumaric, succinic, and malic acid-containing chlorogenic acids, 11 of them not previously reported in nature. These comprise 3-succinoyl-4,5-dicaffeoyl or 1-succinoyl-3,4-dicaffeoylquinic acid, 1,5-dicaffeoyl-3-succinoylquinic acid, 1,5-dicaffeoyl-4-succinoylquinic acid, and 3,4-dicaffeoyl-5-succinoylquinic acid (M(r) 616); 1,3-dicaffeoyl-5-fumaroylquinic acid and 1,5-dicaffeoyl-4-fumaroylquinic acid (M(r) 614); 1,5-dicaffeoyl-3-maloylquinic acid, 1,4-dicaffeoyl-3-maloylquinic acid, and 1,5-dicaffeoyl-4-maloylquinic acid (M(r) 632); 1,3,5-tricaffeoyl-4-succinoylquinic acid (M(r) 778); 1,5-dicaffeoyl-3,4-disuccinoylquinic acid (M(r) 716); 1,5-dicaffeoyl-3-fumaroyl-4-succinoylquinic acid and 1-fumaroyl-3,5-dicaffeoyl-4-succinoylquinic acid (M(r) 714); dicaffeoyl-dimaloylquinic acid (M(r) 748); and 1,5-dicaffeoyl-3-succinoyl-4-dimaloylquinic acid (M(r) 732). All the structures have been assigned on the basis of LC-MS(n) patterns of fragmentation, relative hydrophobicity, and analogy of fragmentation patterns if compared to caffeoylquinic acids. 相似文献
699.
A method for designing plasmonic particles with desired resonance spectra by exploiting the interaction of local geometry with surface charge distribution and applying evolutionary algorithm is presented. The method is based on repetitive perturbations of an initial particle's shape while calculating the eigenvalues of the various quasistatic resonances. Novel family of particles with collocated dipole-quadrupole resonances was designed, as an example for the unique power of the method. 相似文献
700.
Tierney HL Murphy CJ Jewell AD Baber AE Iski EV Khodaverdian HY McGuire AF Klebanov N Sykes EC 《Nature nanotechnology》2011,6(10):625-629
For molecules to be used as components in molecular machines, methods that couple individual molecules to external energy sources and that selectively excite motion in a given direction are required. Significant progress has been made in the construction of molecular motors powered by light and by chemical reactions, but electrically driven motors have not yet been built, despite several theoretical proposals for such motors. Here we report that a butyl methyl sulphide molecule adsorbed on a copper surface can be operated as a single-molecule electric motor. Electrons from a scanning tunnelling microscope are used to drive the directional motion of the molecule in a two-terminal setup. Moreover, the temperature and electron flux can be adjusted to allow each rotational event to be monitored at the molecular scale in real time. The direction and rate of the rotation are related to the chiralities of both the molecule and the tip of the microscope (which serves as the electrode), illustrating the importance of the symmetry of the metal contacts in atomic-scale electrical devices. 相似文献