检索结果-南通市图书馆

Focused electron beam transport through a long narrow metal tube at elevated pressures in the forevacuum range

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2023年第1期25卷 128-134页

作者： ilya BAKEEV Kirill KARPOV Aleksandr KLiMOV Efim OKS aleksey ZENiN Tomsk State University of Control Systems and Radioelectronics Tomskaâ634050Russia institute of High Current Electronics Siberian BranchRussian Academy of SciencesTomskaâ634055Russia

We present here our investigations of the features of focused electron beam transport in free space at elevated pressures of a few *** have explored the effect of the beam accelerating voltage,operating gas pressure,and magnetic focusing upon the trajectory of beam electrons in the crossover region,in particular on the beam convergence and divergence *** is shown that for the forevacuum pressure range of 2-5 Pa explored,a distinctive feature of the propagation of a focused electron beam with a current of up to 20 mA at an accelerating voltage of 10-20 kV is the difference in the angles of convergence(before the focus)and divergence(after the focus).Whereas at a low pressure of 2 Pa the divergence angle is smaller than the convergence angle,as the pressure increases the divergence angle increases and for pressures greater than 5 Pa the divergence angle is greater than the convergence *** results obtained were used in experiments on electron beam transport through a long narrow metal tube with a diameter of 5.8-9.2 mm and length of 10-30 *** show that for a 30 cm long tube of 7.5 mm diameter,the focused beam transmission can exceed 70%.

关键词： focused electron beam plasma electron source forevacuum pressure range long metal tube

Performance of Pr_(2)(Ni,Cu)O_(4+δ) electrodes in protonic ceramic electrochemical cells with unseparated and separated gas spaces

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第34期93卷 157-168页

作者： Artem P.Tarutin Yulia G.Lyagaeva aleksey i.Vylkov Maxim Yu.Gorshkov Gennady K.Vdovin Dmitry A.Medvedev Laboratory of Electrochemical Devices Based on Solid Oxide Proton Electrolytes Institute of High Temperature ElectrochemistryYekaterinburg 620137Russia Ural Federal University Yekaterinburg 620002Russia

The Ln_(2)NiO_(4+δ)-based layered phases have attracted much attention as components for high-performance protonic ceramic fuel cells(PCFCs)and electrolysis cells(PCECs)enabling energy conversion with good efficiency and low *** present paper aims at rationally engineering the Cu-doped Pr_(2)NiO_(4+δ)materials and analysing their electrode behaviour for reversible protonic ceramic cells operating in both PCFC and PCEC *** oxides of Pr_(2)Ni_(1-x)CuxO_(4+δ)(x=0,0.1,0.2 and 0.3)were synthesised using the citrate-nitrate *** obtained materials were characterised considering their crystalline structures,as well as thermal,thermomechanical and electrotransport properties.A special interest was focused on the quality of an electrode/electrolyte interface governing the electrochemical performance of the cells *** is shown that a copper doping of x=0.2 has a positive impact on the thermomechanical compatibility of the Ba(Ce,Zr)O_(3)-based electrolytes,providing a better adhesion to these electrolytes at low-temperature sintering and resulting in a decrease of the polarisation resistance of the air electrodes.A reversible protonic ceramic cell demonstrates a power density of~340 m W cm^(-2) and a hydrogen output flux of~3.8 ml cm^(-2) min^(-1) at 750℃.The presented results propose modernised alkaline-earth-element-free and cobalt-free electrodes that can be successfully used in the electrochemical cells based on the-state-of-the-art proton-conducting electrolytes.

关键词： rSOC Proton conductivity Cathode Cu-doping Thermal expansion impedance spectroscopy

A Wavelet-Free Approach for Multiresolution-Based Grid Adaptation for Conservation Laws

在线全文

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2022年第1期4卷 108-142页

作者： Nils Gerhard Siegfried Müller aleksey Sikstel institut für Geometrie und Praktische Mathematik RWTH AachenTemplergraben 55Aachen 52056Germany

in recent years the concept of multiresolution-based adaptive discontinuous Galerkin(DG)schemes for hyperbolic conservation laws has been *** key idea is to perform a multiresolution analysis of the DG solution using multiwavelets defined on a hierarchy of nested *** this concept is applied to dyadic grid hierarchies where the explicit construction of the multiwavelets has to be performed only for one reference *** non-uniform grid hierarchies multiwavelets have to be constructed for each element and,thus,becomes extremely *** overcome this problem a multiresolution analysis is developed that avoids the explicit construction of multiwavelets.

关键词： Discontinuous Galerkin Grid adaptivity Multiwavelets Multiresolution analysis Conservation laws

Stationary Characteristics of the Single-Server Queue System with Losses and immediate Service Quality Control

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics 2011年第4期2卷 403-409页

作者： aleksey i. Peschansky 不详

Semi-Markovian model of operation of a single-server queue system with losses and immediate service quality control has been built. in case of unsatisfactory request service quality, its re-servicing is carried out. Re-servicing is executed till it is regarded satisfactory. Time between request income, and request service time are assumed to be random values with distribution functions of general kind. An explicit form of the system stationary characteristics has been defined.

关键词： Queue System Semi-Markovian Process System Stationary Characteristics Request Service Quality

Prediction of stable Li-Sn compounds:boosting ab initio searches with neural network potentials

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2022年第1期8卷 1278-1290页

作者： Saba Kharabadze Aidan Thorn Ekaterina A.Koulakova aleksey N.Kolmogorov Department of Physics Applied Physics and AstronomyBinghamton UniversityState University of New YorkPO Box 6000BinghamtonNY13902-6000USA

The Li-Sn binary system has been the focus of extensive research because it features Li-rich alloys with potential applications as battery *** present re-examination of the binary system with a combination of machine learning and ab initio methods has allowed us to screen a vast configuration space and uncover a number of overlooked thermodynamically stable *** ambient pressure,our evolutionary searches identified an additional stable Li3Sn phase with a large BCC-based hR48 structure and a possible high-T LiSn_(4)ground *** building a simple model for the observed and predicted Li-Sn BCC alloys we constructed an even larger viable hR75 structure at an exotic 19:6 *** 20 GPa,low-symmetry 11:2,5:1,and 9:2 phases found with our global searches destabilize previously proposed phases with high Li *** findings showcase the appreciable promise machine-learning interatomic potentials hold for accelerating ab initio prediction of complex materials.

关键词： alloys neural network

Effects of site preparation methods on soil physical properties and outplanting success of coniferous seedlings in boreal forests

维普期刊数据库评论

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 Forestry Research 2024年第2期35卷 70-80页

作者： aleksey S.ilintsev Elena N.Nakvasina Alexander P.Bogdanov Northern Research institute of Forestry 13 Nikitova Str.Arkhangelsk 163062Russian Federation Department of Silviculture and Forest Management Northern(Arctic)Federal University Named After M.V.LomonosovSevernoy Dviny Emb.17Arkhangelsk 163002Russian Federation

This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of *** study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess *** the rooting layer,240 soil samples were taken to determine physical *** study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina ***,reduced soil moisture was noted,particularly in mounds,resulting in increased *** Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the *** treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration *** the Myrtillus and Polytrichum sites,patch scarification had no effects on physical *** Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to *** Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil *** conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.

关键词： Boreal forests Mechanical site preparation Patch scarification Mounding Soil properties Containerised seedlings Bareroot seedlings

Dynamics of annual growth of Pinus sylvestris on industrial wastes of mining companies

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2021年第4期32卷 1385-1393页

作者： Svetlana Bakhtina Yulai Yanbaev aleksey Kulagin Nina Redkina ilgam Masalimov Shamil Fayzrakhmanov Scientific and Educational Center Federal State Budgetary Educational Institution of Higher EducationBashkir State Agrarian University50-Letia Octyabrya Str.34UfaRussia 450001 Department of Forestry and Landscape Design Federal State Budgetary Educational Establishment of Higher EducationBashkir State Agrarian University50-Letia Octyabrya Str.34UfaRussia 450001 Laboratory of Forestry Ufa Institute of BiologyUfa Research Center of Russian Academy of SciencesProspect Octyabrya69UfaRussia 450054 Department of Ecology and Life Safety Federal State Budgetary Educational Institution of Higher EducationBashkir State UniversityZaki Validi Str.32UfaRussia 450076 Department of Mechanics and Engineering Graphics Federal State Budgetary Educational Establishment of Higher EducationBashkir State Agrarian University50-Letia Octyabrya Str.34UfaRussia 450001 Department of Mechanics and Machine Design Federal State Budgetary Educational Establishment of Higher EducationBashkir State Agrarian University50-Letia Octyabrya Str.34UfaRussia 450001

The development of the mining industry has led to the appearance in many parts of the world of vast technogenic territories from which toxic heavy metals enter the environment and food ***,chemical,and biological methods of cleaning industrial land due to technological complexity and hi gh cost are relatively little used on a large *** forest overgrowth of mining sites and the removal of heavy metals by woody plants can be an effective form of ***,the study of this process is of significant scientific and practical *** analysis of the annual growth in height and width of the annual rings of the stem of Scots pine(Pinus sylvestris L.) in 2004-2019 was made on the territory of the Uchalinsky mining and processing plant(South Ural,Russia) contaminated with heavy *** hi gh concentrations of copper and zinc were found in soils,roots,bark,young shoots,comparable to exceeding the maximum allowable *** the spatial uniformity of the heavy metal content in the stands,the tree samples significantly differed in terms of annual *** suggest that the lack of nutrients and not stress from exposure to heavy metals is the main reason for relatively low growth rates on slopes of industrial *** was confirmed by studying the annual growth in height of the undergrowth in habitats with different soil cover *** data prove the relatively high potential of Scots pine for the natural recovery of industrial lands polluted with heavy metals by mining enterprises.

关键词： Annual growth Pinus sylvestris Heavy metals Phytoremediation

Systematization of features and requirements for geological survey of railroad subgrades functioning in cold regions

在线全文

学校读者我要写书评

暂无评论

Research in Cold and Arid Regions 2017年第3期9卷 205-212页

作者： aleksey Lanis Denis Razuvaev Department of Geotechnics Tunnels and Subways the Siberian State University of Railway Engineering Department of Survey Design and Construction of the Railways and Roads the Siberian State University of Railway Engineering

The operation of a railway track in cold regions results in the premature deformation of subgrade soils caused by significant temperature fluctuations and ecological *** and calculation of the thawing degree of permafrost soils,frost heaving of clays,and groundwater flooding require careful engineering and geological *** paper describes the unique,long-standing experience of the university scientists connected with maintaining the Russian EastSiberian and Trans-Baikal Railways'*** features of and requirements for the surveying,depending on the geological and climatic conditions,are identified.

关键词： railroad subgrade engineering-geological survey permafrost soils Baikal-Amur Railroad

Highly Heat-Resistant Materials for Microelectronics:Hydrodynamic,Optical,and Conformational Properties of Fluorine Containing Poly(Amido-ortho-Hydroxy Amide)

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2020年第1期35卷 223-230页

作者： irina A Strelina Liudmila i Rudaya Ol’ga V Okatova Maxim N Bol’shakov aleksey YuMarfichev Galina K Lebedeva Yuliya V Shagayko Stanislav M Ramsh institute of Macromolecular Compounds Russian Academy of SciencesBolshoi pr.VO 31St Petersburg199004 Russia Saint-Petersburg State institute of Technology(Technical University) Moskovskii pr.26St Petersburg190013 Russia

The polycondensation of the mixture of diamines 5,5-methylene bis(2-aminophenol) and 4,4-(hexafluoroisopropylidene)dianiline(molar ratio 0.8:0.2) with isophthaloyl dichloride was used to synthesize poly(amido-o-hydroxy amide)(POA-F)-new heat resistant binder of the composites for microelectronics. The copolymer was fractionated, its hydrodynamic, optical, and conformational properties were researched, and molecular masses(ММ) of the fractions were defined. The polydispersity index was estimated. Based on experimental data, calculation of the size of a segment of Kuhn characterizing degree of an intramolecular orientation order and value of coefficients of the equation of Mark-Kuhn-Hauvink for viscometric and diffusion data were performed. it was demonstrated that introducing 20 mol % of the monomer with-CF3-groups does not lead to any changes in conformational properties of the macromolecules and does not change the degree of intramolecular orientational order(the Kuhn segment length). Optical characteristics of POA-F solutions are virtually similar to the corresponding values for POA prepared with the use of single amine-containing component-5,5-methylene bis(2-aminophenol). The received MM distribution for POA-F(prepolymer) provided the solubility of its films in alkaline solutions. The heat resistance(τ5 and τ10-temperatures corresponding to 5% and of 10% PBO-F mass loss of a polymer) of the powders and the films of PBO, PBO-F were determined. The electrophysical parameters-dielectric permittivity(ε) and dielectric loss tangent(tan δ) of the PBO-F films decreased down to 3.30 and 0.017, in comparison 3.40 and 0.025 for PBO respectively.

关键词： poly(o-hydroxy amide) 4,4-(hexafluoroisopropylidene) dianiline Kuhn segment Mark-Kuhn-Houwink equations translational diffusion intrinsic viscosity flow birefringence