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121.
Yurii S. Kovshov Sergey S. Ponomarenko Sergey S. Kishko Alexander Likhachev Alexander Danik Lyudmila Mospan Sergiy Steshenko Eduard M. Khutoryan Alexei N. Kuleshov 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(11):1055-1064
Extension of the theory of a clinotron is developed by use of the scattering matrix of an oversized T-junction on the ends of a slow wave system. The matrix contains elements corresponding to the transformation of slow grating modes into fast ones and vice versa. Those fast waves with low ohmic losses provide strong resonant properties of a clinotron even in the case of strong attenuation of the surface mode. Results of the theoretical simulation are compared with experimental ones and obtained dependencies explain strong resonances in sub-THz clinotrons. 相似文献
122.
123.
Sergiy Kotrechko Oleksandr Ovsjannikov Tatjana Mazilova Igor Mikhailovskij Evgenij Sadanov 《哲学杂志》2013,93(12):930-943
AbstractExperimental value of strength of nano-sized crystal under uniform triaxial (hydrostatic) tension was obtained for the first time. Strength was measured by in situ high-field mechanical testing of tungsten defect-free nano-sized specimen carried out inside a field-ion microscope. At temperature 77 K, this strength is 28 ± 3 GPa. Based on the MD simulation findings, it is ascertained that under these conditions the instability of an entire nano-sized specimen (global instability) is initiated by the Bain transition within a local region of the specimen. The model of ‘fluctuation-induced Bain transition’ is offered. Within the framework of the model proposed, it is exhibited that possibility of realisation of such local Bain transition under global hydrostatic tension is due to the fluctuation of local tensile stresses. In general, it is shown that fluctuation-induced Bain transition governs the level of the strength of nano-sized bcc crystals under hydrostatic tension. 相似文献
124.
Sergiy Shklyar Georgiy Shevchenko Yuliya Mishura Vadym Doroshenko Oksana Banna 《Methodology and Computing in Applied Probability》2014,16(3):539-560
We study the problem of optimal approximation of a fractional Brownian motion by martingales. We prove that there exists a unique martingale closest to fractional Brownian motion in a specific sense. It shown that this martingale has a specific form. Numerical results concerning the approximation problem are given. 相似文献
125.
A network-based data mining approach to portfolio selection via weighted clique relaxations 总被引:1,自引:0,他引:1
Vladimir Boginski Sergiy Butenko Oleg Shirokikh Svyatoslav Trukhanov Jaime Gil Lafuente 《Annals of Operations Research》2014,216(1):23-34
We introduce a new network-based data mining approach to selecting diversified portfolios by modeling the stock market as a network and utilizing combinatorial optimization techniques to find maximum-weight s-plexes in the obtained networks. The considered approach is based on the weighted market graph model, which is used for identifying clusters of stocks according to a correlation-based criterion. The proposed techniques provide a new framework for selecting profitable diversified portfolios, which is verified by computational experiments on historical data over the past decade. In addition, the proposed approach can be used as a complementary tool for narrowing down a set of “candidate” stocks for a diversified portfolio, which can potentially be analyzed using other known portfolio selection techniques. 相似文献
126.
In this article we report accurate nonrelativistic variational calculations of the ground and two excited states of C(+) ion. We employ extended and well optimized basis sets of all-electron explicitly correlated Gaussians to represent the wave functions of the states. The optimization of the basis functions is performed with a procedure employing the analytic gradient of the energy with respect to the nonlinear parameters of the Gaussians. The calculations explicitly include the effects due to the finite nuclear mass. The calculated transition energies between the three states are compared to the experimentally derived values. Finally, we present expectation values of some small positive and negative powers of the interparticle distances and contact densities. 相似文献
127.
Vladimir Rossikhin Eugene Voronkov Sergiy Okovytyy Tetiana Sergeieva Karina Kapusta Jerzy Leszczynski 《International journal of quantum chemistry》2014,114(11):689-695
An efficient procedure for construction of physically rationalized Slater‐type basis sets for calculations of dynamic hyperpolarizability is proposed. Their performance is evaluated for the DFT level calculations for model molecules, carried out with a series of functionals. Advantages of new basis sets over standard d‐aug‐cc‐pVTZ and recently developed LPOL‐(FL,FS) Gaussian‐type basis sets are discussed. © 2014 Wiley Periodicals, Inc. 相似文献
128.
Atomic diffusion in deformed Pd(40)Ni(40)P(20) bulk metallic glass containing a single family of deformation-induced shear bands was measured by the radiotracer technique. The significant, by orders of magnitude, enhancement of the diffusion rate with respect to that in the untransformed matrix suggests that the shear bands represent short-circuit diffusion paths. Correlations between diffusivity, viscosity, and the excess free volume distribution inside of shear bands are discussed. 相似文献
129.
Pareek A Borodin S Bashir A Ankah GN Keil P Eckstein GA Rohwerder M Stratmann M Gründer Y Renner FU 《Journal of the American Chemical Society》2011,133(45):18264-18271
Dealloying is widely utilized but is a dangerous corrosion process as well. Here we report an atomistic picture of the initial stages of electrochemical dealloying of the model system Cu(3)Au (111). We illuminate the structural and chemical changes during the early stages of dissolution up to the critical potential, using a unique combination of advanced surface-analytical tools. Scanning tunneling microscopy images indicate an interlayer exchange of topmost surface atoms during initial dealloying, while scanning Auger-electron microscopy data clearly reveal that the surface is fully covered by a continuous Au-rich layer at an early stage. Initiating below this first layer a transformation from stacking-reversed toward substrate-oriented Au surface structures is observed close to the critical potential. We further use the observed structural transitions as a reference process to evaluate the mechanistic changes induced by a thiol-based model-inhibition layer applied to suppress surface diffusion. The initial ultrathin Au layer is stabilized with the intermediate island morphology completely suppressed, along an anodic shift of the breakdown potential. Thiol-modification induces a peculiar surface microstructure in the form of microcracks exhibiting a nanoporous core. On the basis of the presented atomic-scale observations, an interlayer exchange mechanism next to pure surface diffusion becomes obvious which may be controlling the layer thickness and its later change in orientation. 相似文献
130.
Lucas C. Recco Dr. Ihor Tokarev Prof. Dr. Sergiy Minko Prof. Dr. Valber A. Pedrosa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(5):1226-1230
Herein we demonstrate a plasmonic nanobiosensor that explores chain reaction amplification mechanisms to transduce chemical signals released in biocatalytic reactions, turning optical signals into a visual spectral range. The sensor has a very simple design: gold nanoparticles resting in the surface of a grafted P2VP film. Changes in the gold nanoparticles’ position causes changes in the plasmon coupling mode. This is detected by means of a maximum absorbance shift. 相似文献