检索结果-南通市图书馆

Assessing suspended sediment fluxes with acoustic Doppler current profilers:case study from large rivers in Russia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Big Earth Data 2022年第4期6卷 504-526页

作者： Sergey Chalov Vsevolod Moreido Victor Ivanov Aleksandra Chalova Faculty of Geography Lomonosov Moscow State UniversityMoscowRussia institute of Physics Kazan Federal UniversityKazanRussia Flood Hydrology Lab Water Problems Institute of Russian Academy of SciencesMoscowRussia

Surrogate measures are becoming increasingly used to measure suspended sediment flux,but only few particular computer techniques of data processing are recently *** study demonstrates capabilities of acoustic Doppler current profilers(ADCPs)to infer information regarding suspended-sand concentrations in river systems and calculate suspended sediment flux via big data analytics which includes process of analyzing and data mining of measurements based on ADCP signal backscatter intensity *** present here specific codes done by R language using RStudio software with open-source tidyverse and plotly packages aimed to generate tables containing data of suspended load for cells,verticals and whole cross-section based on backscattering values from 600 kH Teledyne RDInstruments RioGrande WorkHorse ADCP unit,as well perform estimates of morphometric,suspended sediment concentration(SSC)and velocity characteristics of the *** developed tools enabled to process large data array consisting of over 56,526,480 geo-referenced values of river depth,streamflow velocity,and backscatter intensity for each river cross-section measured at six case study sites in Russia.

关键词： Big data ADCP backscatter intensity sediment transport

Considering temperature dependence of thermo-physical properties of sandy soils in two scenarios of oil pollution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Cold and Arid Regions 2014年第4期6卷 302-308页

作者： Aleksey V.Malyshev Anatoly M.Timofeev institute of Physical-Technical problems of the North. V.P. Larionov Siberian Branch of the Russian Academy of Sciences

We analyzed the heat conductivity and volumetric heat capacity of sandy soil contaminated in two scenarios of oil pollution, and also determined the temperature dependencies of these changed thermophysical properties. In the first pollution scenario, the oil product was introduced into wet river sand, and in the second case, dry sand was contaminated by the oil product and was then moistened with water. By considering these two scenarios as multicomponent dispersion systems with varying degrees of contamination and humidity, and by using a polystructural granular model with pore spaces and closed inclusions, we calculated that the heat conductivity of the sandy soil increased under the first pollution scenario and decreased under the second, but the change in the volumetric heat capacity of the sandy soil was proportional only to the amount of oil pollution, not the manner in which it was introduced. We also determined the temperature dependencies of these two thermophysical properties of sandy soil when polluted by oil, of which information will be useful for future containment and remediation of oil-contaminated soil.

关键词： sandy soil heat conductivity heat capacity heat resistance pollution oil product unfrozen water volumeconcentration coordination number

Evidence of Electronic Phase Separation in the Strongly Correlated Semiconductor YbB_(12)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2022年第12期39卷 65-70页

作者： A.Azarevich N.Bolotina O.Khrykina A.Bogach E.Zhukova B.Gorshunov A.Melentev Z.Bedran A.Alyabyeva M.Belyanchikov V.Voronov N.Yu.Shitsevalova V.B.Filipov N.Sluchanko Prokhorov General Physics institute of the russian academy of sciences Vavilov Str.38Moscow 119991Russia Shubnikov institute of Crystallography Federal Scientific Research Centre‘Crystallography and Photonics’of Russian Academy of Sciences59 Leninskiy ProspectMoscow 119333Russia Center for Photonics and 2D Materials Moscow Institute of Physics and Technology(National Research University)141700 DolgoprudnyMoscow RegionRussia institute for problems of Materials Science NASUKrzhizhanovsky Str.303142 KyivUkraine

We investigate high-quality single-domain crystals of YbB_(12)using the precise x-ray diffraction technique in combination with the low-temperature polarized THz–infrared spectroscopy and accurate magnetotransport *** is shown for the first time that this archetypal strongly correlated system with a metal-insulator transition to a mysterious dielectric ground state with a metal Fermi surface[Science 362,65(2018)and ibid 362,32(2018)]is actually a heterogeneous compound in the regime of electronic phase *** in the configuration of the discovered dynamic charge stripes are proposed upon *** a result,a conclusion is drawn in favor of a crossover between different patterns of the filamentary electronic structure penetrating the semiconducting matrix of YbB_(12).We argue that the discovery of stripes in YbB_(12)is fundamental,elucidating the nature of exotic dielectric state in Kondo insulators.

关键词： insulator Kondo dielectric

2024 aluminum alloy ultrahigh-strength sheet due to two-level nanostructuring under cryorolling and heat treatment

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2020年第1期30卷 14-26页

作者： Stanislav KRYMSKIY Oleg SITDIKOV Elena AVTOKRATOVA Michael MARKUSHEV institute for Metals Superplasticity problems Russian Academy of Sciences39 Khalturin str.Ufa 450001Russia

The effect of rolling to a total effective strain of 2 at the liquid nitrogen temperature and subsequent natural and artificial aging on the structure and service properties of the pre-quenched hot-pressed 2024 aluminum alloy was *** optical and electron microscopy,and X-ray analysis,it was found that the cryorolling did not qualitatively change the type of the initial coarse-fibered microstructure,but produced a well-developed nanocell substructure inside *** aging led to decomposition of the preliminary supersaturated and work-hardened aluminum solid solution and precipitation of strengthening phases in the statically recovered and/or recrystallized *** a result,the rolled and naturally aged alloy demonstrated the yield and ultimate tensile strengths(YS=590 MPa,UTS=640 MPа)much higher than those in the pressed andТ6-heat treated alloy at equal elongation to failure(El^6%).Artificial aging at a temperature less than conventional T6 route could provide the extra alloy strengthening and the unique balance of mechanical properties,involving enhanced strength(YS=610 MPa,UTS=665 MPа)and ductility(El^10%),and good static crack resistance(the specific works for crack formation and growth were 42 and 18 k J/m^2,respectively)and corrosion resistance(the intensity and depth of intercrystalline corrosion were 23%and 50μm,respectively).

关键词： aluminum alloy cryogenic rolling heat treatment nanostructure mechanical behavior intergranular corrosion

Mathematical Modeling of Cardiomyocytes’ and Skeletal Muscle Fibers’ Membrane: Interaction with External Mechanical Field

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics 2013年第8期4卷 1-6页

作者： Irina V. Ogneva Nikolay S. Biryukov Department of Molecular Biomedicine State Scientific Center of Russian Federation Institute of Biomedical Problems of the Russian Academy of Sciences Moscow Russia

We propose a mathematic model of muscle cell membrane based on thin-walled elastic rod theory. A deformation occurs in rodents’ skeletal and cardiac cells during a period of antiorthostatic suspension. We carried out a quantitative evaluation of the deformation using this model. The calculations showed the deformation in cardiac cells to be greater than in skeletal ones. This data corresponds to experimental results of cell response that appears intense in cardiomyocytes than in skeletal muscle cells. Moreover, the deformation in skeletal and heart muscle cells has a different direction (stretching vs. compression), corresponding to experimental data of different adaptive response generation pathways in cells because of external mechanical condition changes.

关键词： Mathematical Modeling in Biology Muscle Cell Cell Mechanosensitivity Microgravity

Concerning spikes in emission and absorption in the microwave range

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2013年第1期13卷 115-128页

作者： Gennady P.Chernov Robert A.Sych Guang-Li Huang Hai-Sheng Ji Yi-Hua Yan Cheng-Ming Tan Key Laboratory of Solar Activity National Astronomical ObservatoryChinese Academy of Sciences Pushkov institute of Terrestrial Magnetism Ionosphere and Radio Wave PropagationRussian Academy of Sciences (IZMIRAN) institute of Solar-Terrestrial Physics Purple Mountain Observatory Chinese Academy of Sciences

In some events, weak fast solar bursts （near the level of the quiet Sun） were observed in the background of numerous spikes in emission and absorption. In such a case, the background contains the noise signals of the receiver. In events on 2005 September 16 and 2002 April 14, the solar origin of fast bursts was confirmed by simultaneous recording of the bursts at several remote observatories. The noisy background pixels in emission and absorption can be excluded by subtracting a higher level of continuum when constructing the spectra. The wavelet spectrum, noisy pro- files in different polarization channels and a spectrum with continuum level greater than zero demonstrates the noisy character of pixels with the lowest levels of emission and absorption. Thus, in each case, in order to judge the solar origin of all spikes, it is necessary to determine the level of continuum against the background of which the solar bursts are observed. Several models of microwave spikes are discussed. The electron cyclotron maser emission mechanism runs into serious problems with the in- terpretation of microwave millisecond spikes： the main obstacles are too high values of the magnetic field strength in the source （Pe 〈 uB）. The probable mechanism is the interaction of plasma Langmuir waves with ion-sound waves （l ＋ s → t） in a source related to shock fronts in the reconnection region.

关键词： solar flare -- radio emission -- spike-bursts

A review on magneto-optical ceramics for Faraday isolators

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2023年第5期12卷 873-915页

作者： Lixuan Zhang Dianjun Hu Ilya LSnetkov Stanislav Balabanov Oleg Palashov Jiang Li Transparent Ceramics Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China institute of Applied Physics of the russian academy of sciences Nizhny Novgorod 603950Russia Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603950Russia G.G.Devyatykh institute of Chemistry of High-Purity Substances Russian Academy of SciencesNizhny Novgorod 603951Russia

As a promising magneto-optical(MO)material applied in Faraday isolators,magneto-optical ceramics possess excellent comprehensive properties and have attracted much attention these ***,we review the fabrication and properties of magneto-optical ceramics including garnet,sesquioxide,and A_(2)B_(2)O_(7) *** of the ceramics have been proved to possess applicable performance,while further studies are still needed for most of the magneto-optical *** at the application for isolators,the research status,existing problems,and development trends of magneto-optical ceramics are shown and discussed in this review.

关键词： magneto-optical(MO)ceramics Faraday isolators optical quality thermo-optical effects

On One Possibility of Closuring the Chain of Equations for Statistical Moments in Turbulence Theory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Physics 2013年第1期4卷 56-63页

作者： Edward V. Teodorovich The institute for problems in Mechanics Russian Academy of Sciences Moscow Russia

The paper concerns the problem on statistical description of the turbulent velocity pulsations by using the method of characteristic functional. The equations for velocity covariance and Green’s function, which describes an average velocity response to external force action, have been obtained. For the nonlinear term in the equation for velocity covariance, it has been obtained an exact representation in the form of two terms, which can be treated as describing a momentum transport due to turbulent viscosity and action of effective random forces (within the framework of traditional phenomenological description, the turbulent viscosity is only accounted for). Using a low perturbation theory approximation for high statistical moments, a scheme of closuring the chain of equations for statistical moments is proposed. As the result, we come to a closed set of equations for velocity covariance and Green’s function, the solution to which corresponds to summing up a certain infinite subsequence of total perturbation series.

关键词： Random Velocity Field Statistical Description Characteristic Functional Chain of Equations for Moments Problem of Closuring

An Approach to Plasma Wake Studying

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Physics 2015年第1期6卷 46-57页

作者： Gennadii V. Gembarzhevskii russian academy of sciences The Institute for Problems in Mechanics Moscow Russia

The influence of a glow electrical discharge on the wake behind two cylinders was studied. This effect consists in a redistribution of the power in the velocity pulsation spectrum due to the discharge action on fluid flow. To treat this observation, we need a simple model of intermittent turbulent wake in the vicinity of cylinders. A variant of such model has been developed in the form of two coupled van-der-Pole oscillators representing two interacting von Karman vortex streets behind the cylinders. According to the model, the set of the global wake modes and its concurrence are discussed. Accordingly, a mechanism of the glow discharge effect on the cylinders wake has been proposed.

关键词： Turbulentplasma Wake Alternation Over-Heating Instability Reduced-Order Model Van-der-Pole Oscillators Vortex Streets Synchronization