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61.
A. V. Favorskaya I. B. Petrov D. I. Petrov N. I. Khokhlov 《Mathematical Models and Computer Simulations》2016,8(4):348-357
The aim of this work is the numerical simulation of wave propagation in media with linear-elastic and acoustic layers as exemplified by the seismic prospecting problems in the Arctic region and the explosive impact on an iceberg. The complete system of equations describing the state of a linearly elastic body and the system of equations describing the acoustic field are solved. The grid-characteristic method is used to provide the contact and boundary conditions, including the contact condition between acoustic and linear-elastic layers, to be correctly described. 相似文献
62.
A mathematical model is proposed for the proximity dynamics of political positions of interacting individuals which form a closed group. The model is described as a system of ordinary differential equations. The results of numerical experiments for the system are presented and a number of substantial conclusions are formulated. It is shown that in the case of two individuals the system has an asymptotically stable zero steady state. In the case of two individuals and two themes we get an infinite number of stationary states, all except the zero state being unstable. 相似文献
63.
Vladislav Rutenburg 《Annals of Mathematics and Artificial Intelligence》1994,10(3):207-231
Truth maintenance (TM) has been an active area of artificial intelligence (AI) research in recent years. In particular, truth maintenance systems (TMSs) in many variant types have become popular mechanisms for implementing nonmonotonic inference systems. Knowledge about the computational foundations of a TMS is indispensable for their use. We present a classification of computational complexity of tasks performed by basic existing TMS types. Our results include the proof
2
p
-completeness of the clause maintenance system's computation task. This is the first problem in AI proved to be
2
p
-complete. It is likely to provide a basis for proving
2
p
-completeness of other problems in logic and AI. As part of the proof, we prove the
2
p
-completeness of the generalized node deletion problem, one of the first natural graph problems to be complete for any one of the classes
i
p
, forp>1. We also prove the polynomial equivalence of Boolean Constraint Propagation-based (logic-based) approaches (LTMSs) and justification-based approaches (JTMSs) to TM, and exhibit efficient algorithms for transforming an LTMS into a JTMS and vice versa. 相似文献
64.
V. M. Bashmakov B. S. Sirozhev G. N. Petrov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1995,29(12):681-689
1. | In connection with the historically established economic conditions and existing agreements with neighboring countries, the cascade of Vakhsh hydrostation was designed on the basis of operating conditions in an irrigation regime and cannot provide Tajikistan's own need for power in the winter, the deficit of which is 4 billion kWh/yr. The traditional methods of solving this problem call for the construction of either an irrigation reregulator in the lower course of the river or a hydrostation operating in a power compensator regime in its upper course. Both these variants require vast expenditures of material and financial resources and provide an effect just due to one particular hydro development. |
2. | The natural conditions of Tajikistan created the unique possibility of increasing the effectiveness of the combined operation of the Vakhsh cascade by constructing a tunnel conduit and using the runoff of the Pyandzh River in operating the Vakhsh hydrostations. With minimum construction costs the power effect of the cascade in this case increases substantially since it is achieved due to the repeated use of Pyandzh River water at all stations of the cascade and without any detriment for irrigation. |
3. | Realization of the proposed project will increase the total power production of the cascade for all hydrostations specified by the scheme depending on the degree of streamflow regulation by the Pyandzh reservoir. The cost effectiveness of the proposed project is an order higher than that of the traditional variants. Even for the stations operating today on the cascade its effect is comparable to the effect of the Nurek hydrostation with respect to all indices. Here the total cost of the tunnel conduit together with the dam is an order lower than the cost of the Nurek hydro development. |
65.
66.
Kseniia A. Sergeeva Dmitrii V. Pavlov Albert A. Seredin Eugeny V. Mitsai Aleksandr A. Sergeev Evgeny B. Modin Anastasiia V. Sokolova Tsz Chun Lau Kseniia V. Baryshnikova Mihail I. Petrov Stephen V. Kershaw Aleksandr A. Kuchmizhak Kam Sing Wong Andrey L. Rogach 《Advanced functional materials》2023,33(44):2307660
In order to advance the development of quantum emitter-based devices, it is essential to enhance light-matter interactions through coupling between semiconductor quantum dots with high quality factor resonators. Here, efficient tuning of the emission properties of HgTe quantum dots in the infrared spectral region is demonstrated by coupling them to a plasmonic metasurface that supports bound states in the continuum. The plasmonic metasurface, composed of an array of gold nanobumps, is fabricated using single-step direct laser printing, opening up new opportunities for creating exclusive 3D plasmonic nanostructures and advanced photonic devices in the infrared region. A 12-fold enhancement of the photoluminescence in the 900–1700 nm range is observed under optimal coupling conditions. By tuning the geometry of the plasmonic arrays, controllable shaping of the emission spectra is achieved, selectively enhancing specific wavelength ranges across the emission spectrum. The observed enhancement and shaping of the emission are attributed to the Purcell effect, as corroborated by systematic measurements of radiative lifetimes and optical simulations based on the numerical solution of Maxwell's equations. Moreover, coupling of the HgTe photoluminescence to high quality factor modes of the metasurface improves emission directivity, concentrating output within an ≈20° angle. 相似文献
67.
Weber Lukas Vinon Tobias Kndler Christian Solis-Vasquez Leonardo Bernhardt Arthur Petrov Ilia Koch Andreas 《Distributed and Parallel Databases》2022,40(1):27-45
Distributed and Parallel Databases - Massive data transfers in modern data-intensive systems resulting from low data-locality and data-to-code system design hurt their performance and scalability.... 相似文献
68.
A. A. Zatsiupa L. A. Bashkirov I. A. Vialikanava G. S. Petrov S. V. Shevchenko 《Inorganic Materials》2016,52(4):361-366
Bi2–хLaхFe4O9 and Bi2Fe4–2xTixCoxO9 ferrites have been prepared by solid-state reactions at a temperature of 1073 K. X-ray diffraction data indicate that, in the Bi2–хLaхFe4O9 system, the limiting degree of La3+ substitution for Bi3+ ions in Bi2Fe4O9 does not exceed 0.05 and that the limiting degree of substitution in the Bi2Fe4–2xTixCoxO9 system lies in the range 0.05 < x < 0.1. The specific magnetization and specific magnetic susceptibility of the samples have been measured at temperatures from 5 to 300 K in a magnetic field of 0.86 T. The field dependences of magnetization obtained for the Bi2–хLaхFe4O9 and Bi2Fe4–2xTixCoxO9 ferrites at temperatures of 300 and 5 K demonstrate that partial isovalent substitution of La3+ for Bi3+ ions in Bi2Fe4O9 and heterovalent substitution of Ti4+ and Co2+ ions for two Fe3+ ions leads to partial breakdown of the antiferromagnetic state and nucleation of a ferromagnetic state. 相似文献
69.
We demonstrate difference-frequency generation in the 6.8-12.5-mum range by mixing two high-power single-frequency laser diodes in a type II AgGaS(2) crystal. This compact all-solid-state scheme provides maximum output powers that exceed 1 muW and permits continuous adjustment-free scans larger than 2 cm(-1) across the entire tuning range. 相似文献
70.