检索结果-南通市图书馆

Quaternion methods and models of regular celestial mechanics and astrodynamics

Applied mathematics and mechanics(English Edition) 2022年第1期43卷 21-80页

作者： Y.N.CHELNOKOV institute of Precision mechanics and Control Russian Academy of SciencesSaratov410031Russia

This paper is a review,which focuses on our work,while including an analysis of many works of other researchers in the field of quaternionic *** regular quaternion models of celestial mechanics and astrodynamics in the Kustaanheimo-Stiefel(KS)variables and Euler(Rodrigues-Hamilton)parameters are *** models are derived by the quaternion methods of mechanics and are based on the differential equations of the perturbed spatial two-body problem and the perturbed spatial central motion of a point *** paper also covers some applications of these *** and Scheifele are known to have doubted that quaternions and quaternion matrices can be used efficiently to regularize the equations of celestial ***,the author of this paper and other researchers refuted this point of view and showed that the quaternion approach actually leads to efficient solutions for regularizing the equations of celestial mechanics and *** paper presents convenient geometric and kinematic interpretations of the KS transformation and the KS bilinear relation proposed by the present *** general(compared with the KS equations)quaternion regular equations of the perturbed spatial two-body problem in the KS variables are *** equations are derived with the assumption that the KS bilinear relation was not *** main stages of the quaternion theory of regularizing the vector differential equation of the perturbed central motion of a point particle are presented,together with regular equations in the KS variables and Euler parameters,derived by the aforementioned *** also present the derivation of regular quaternion equations of the perturbed spatial two-body problem in the Levi-Civita variables and the Euler parameters,developed by the ideal rectangular Hansen coordinates and the orientation quaternion of the ideal coordinate *** paper also gives new results using quaternionic methods in the pertur

关键词： celestial mechanics astrodynamics perturbed spatial two-body problem central motion regularization Levi-Civita and Kustaanheimo-Stiefel(KS)variables Euler parameter quaternion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evolution of ionization waves in a multi-pulsed plasma jet:the role of memory charges

引用

Plasma Science and Technology 2023年第3期25卷 95-103页

作者： N Yu BABAEVA G V NAIDIS V F TARASENKO D A SOROKIN Cheng ZHANG Tao SHAO Joint institute for High Temperatures Russian Academy of Sciences institute of High Current Electronics Siberian BranchRussian Academy of Sciences institute of Electrical Engineering Chinese Academy of Sciences University of Chinese academy of sciences

In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational *** IWs are generated by application of three short negative pulses with a repetition frequency 12.5 *** simulations are performed continuously during a single run while accounting for charges accumulated inside(surface charges)and outside(space charges)the *** plasma forming gas mixture(He/O2=99.8%/0.2%)is injected through the discharge tube into the surrounding humid *** show that an IW can emerge from the tube exit at a pulse rising edge(as a negative IW)and at a falling edge of the same pulse(as a positive IW).It is demonstrated that remnants of the negative and positive charges play an essential role in the discharge *** first pulse travels the shortest distance as it propagates through the initially non-ionized *** IWs developing during the second pulse essentially enlarge the plasma plume *** the same time,the IWs generated by the third pulse eventually decay due to the remnants of charges accumulated during the previous *** memory charges can lead to the IW extinction.

关键词： helium plasma jet multiple pulses positive and negative ionization waves

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Inverse Problems in Graph Theory: Nets

引用

Communications in mathematics and Statistics 2019年第1期7卷 69-83页

作者： A.A.Makhnev M.P.Golubyatnikov Wenbin Guo institute of mathematics and mechanics Ural Branch of the Russian Academy of SciencesYekaterinburgRussia ural Federal University named after the First President of Russia B.N.Yeltsin YekaterinburgRussia University of Science and Technology of China HefeiChina

Let Г be a distance-regular graph of diameter 3 with strong regular graph Г_(3).The determination of the parameters Г_(3) over the intersection array of the graph Г is a direct *** an intersection array of the graph Г with respect to the parameters Г_(3) is an inverse ***,inverse problemswere solved for Г_(3) by Makhnev and *** this paper,we study the intersection arrays of distance-regular graph Г of diameter 3,for which the graph Г_(3) is a pseudo-geometric graph of the net PGm(n,m).New infinite series of admissible intersection arrays for these graphs are *** also investigate the automorphisms of distance-regular graph with the intersection array{20,16,5;1,1,16}.

关键词： Distance-regular graph Pseudo-geometric graph Strong regular graph

来源：

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

UNSTEADY MODEL OF DROP MARANGONI MIGRATION IN MICROGRAVITY

引用

Acta Mechanica Sinica 2002年第3期18卷 227-234页

作者：耿荣慧胡文瑞金友兰敖超 institute of mechanics Chinese Academy of Sciences Beijing China 100080 institute of Computational mathematics Chinese Academy of Sciences Beijing China 100080

The experiments of drop Marangoni migration have been performed by the drop shift facility of short period of 4.5 s, and the drop accelerates gradually to an asymptotic velocity during the free fall. The unsteady and axisymmetric model is developed to study the drop migration for the case of moderate Reynolds numberRe=O(1), and the results are compared with the experimental ones in the present paper. Both numerical and experimental results show that the migration velocity for moderate Reynolds number is several times smaller than that given by the linear YGB theory.

关键词： drop migration thermocapillary effect microgravity fluid mechanics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Non-classical solutions of a continuum model for rock descriptions

引用

Journal of Rock mechanics and Geotechnical Engineering 2014年第3期6卷 180-185页

作者： Mikhail A.Guzev institute for Applied mathematics Far Eastern Branch of the Russian Academy of Sciences

The strain-gradient and non-Euclidean continuum theories are employed for construction of non- classical solutions of continuum models. The linear approximation of both models＇ results in identical structures in terms of their kinematic and stress characteristics. The solutions obtained in this study exhibit a critical behaviour with respect to the external loading parameter. The conclusions are obtained based on an investigation of the solution for the scalar curvature in the non-Euclidean continuum theory, The proposed analysis enables us to use different theoretical approaches for description of rock critical behaviour under different loading conditions.

关键词： Zonal disintegrationStrain-gradient theoryNon-Euclidean continuum model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computer study of the spectral characteristics of the disperse water methane system

引用

Chinese Physics B 2013年第12期22卷 238-242页

作者： A.Y.Galashev institute of Industrial Ecology Ural Branch Russian Academy of Sciences 62099S. Kovalevskaya Str. 20 Yekaterinburg Russia

The interaction of water clusters that adsorbed methane molecules with infrared radiation is studied by molecular dynamics. The presence of methane molecules in the disperse water system leads to an increase in absorption and emission of infrared radiation and a strong depletion of the Raman spectrum. In this case, the reflection coefficient of a monochromatic plane electromagnetic wave increases and its frequency spectrum significantly changes. The comparison of experimental data for similar characteristics of water, methane, or their mixtures is presented.

关键词： adsorption methane water cluster infrared and Raman spectra

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Musical Isomorphisms and Problems of Lifts

引用

Chinese Annals of mathematics,Series B 2016年第3期37卷 323-330页

作者： Rabia CAKAN Kursat AKBULUT Arif SALIMOV Department of mathematics Ataturk University Azerbaijan National academy of sciences Institute of Mathematics and Mechanics

Using the complete lift on tangent bundles, the authors construct the complete lift on cotangent bundles of tensor fields with the aid of a musical isomorphism. In this new framework, the authors have a new intrepreta... 详细信息

关键词： Tensor fields Cotangent bundles Complete lift Anti-Hermitian metric Riemannian extension

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Climate change evidence in tree growth and stand productivity at the upper treeline ecotone in the Polar ural Mountains

引用

Forest Ecosystems 2020年第1期7卷 76-91页

作者： Nadezhda M.Devi Vladimir V.Kukarskih Аrina A.Galimova Valeriy S.Mazepa Andrey A.Grigoriev institute of Plant and Animal Ecology Ural BranchRussian Academy of Sciences8 Marta202/3Ekaterinburg 620144Russia

Background:Recent warming is affecting species composition and species areal distribution of many ***,although most treeline studies have estimated the rates of forest expansion into tundra,still little is known about the long-term dynamic of stand productivity at the forest-tundra ***,we make use of tree-ring data from 350 larch(Larix sibirica Ledeb.)and spruce(Picea obovata Ledeb.)sampled along the singular altitudinal treeline ecotone at the Polar urals to assess the dynamic of stand establishment and productivity,and link the results with meteorological observations to identify the main environmental ***:The analysis of stand instalment indicated that more than 90%of the living trees appeared after *** this period,the stand became denser and moved 50m upward,while in recent decades the trees of both species grew *** maximum afforestation occurred in the last decades of the twentieth century,and the large number of encountered saplings indicates that the forest is still *** upward shift coincided with a slight increase of May-August and nearly doubling of September-April precipitation while the increase in growth matched with an early growth season warming(June+0.27°C per decade since 1901).This increase in radial growth combined with the stand densification led to a 6-90 times increase of biomass since ***:Tree-ring based twentieth century reconstruction at the treeline ecotone shows an ongoing forest densification and expansion accompanied by an increased *** changes are driven by climate change mechanism,whereby the leading factors are the significant increase in May-June temperatures and precipitation during the dormant *** of phytomass accumulation mechanisms within treeline ecotone is valuable for improving our understanding of carbon dynamics and the overall climate balance in current treeline ecosystems and for predicting how these will be altered by global ch

关键词： Polar urals Treeline Productivity Climate change Radial growth Recruitment Larch Spruce

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Novel Methodologies for Preventing Crack Propagation in Steel Gas Pipelines Considering the Temperature Effect

引用

Structural Durability & Health Monitoring 2025年第1期19卷 1-23页

作者： Nurlan Zhangabay Ulzhan Ibraimova Marco Bonopera Ulanbator Suleimenov Konstantin Avramov Maryna Chernobryvko Aigerim Yessengali Department of Architecture and Urban Planning Mukhtar Auezov South Kazakhstan UniversityShymkent160012Kazakhstan Department of Industrial Civil and Road Construction Mukhtar Auezov South Kazakhstan UniversityShymkent160012Kazakhstan mechanics Sound&Vibration LaboratoryDepartment of Civil EngineeringCollege of EngineeringNational Taiwan UniversityTaipei10617Taiwan Department of Reability&Dynamic Strength A.Pidhornyi Institute of Mechanical Engineering Problems of National Academy of Sciences of UkraineKharkiv61046Ukraine

Using the software ANSYS-19.2/Explicit Dynamics,this study performedﬁnite-element modeling of the large-diameter steel pipeline cross-section for the Beineu-Bozoy-Shymkent gas pipeline with a non-through straight crack,strengthened by steel wire *** effects of the thread tensile force of the steel winding in the form of single rings at the crack edges and the wires with different winding diameters and pitches were also *** results showed that the strengthening was preferably executed at a minimum value of the thread tensile force,which was 6.4%more effective than that at its maximum *** analysis of the inﬂuence of the winding dia-meters showed that the equivalent stresses increased by 32%from the beginning of the crack growth until the wire *** increment in winding diameter decelerated the disclosure of the edge crack and reduced its length by 8.2%.The analysis of the inﬂuence of the winding pitch showed that decreasing the distance between the winding turns also led to a 33.6%reduction in the length of the straight crack and a 7.9%reduction in the maximum stres-ses on the strengthened pipeline *** analysis of the temperature effect on the pipeline material,within a range from-40℃ to+50℃,resulted in a crack length change of up to 5.8%.As the temperature dropped,the crack length *** such a temperature range,the maximum stresses were observed along the cen-tral area of the crack,which were equal to 413 MPa at+50℃ and 440 MPa at-40℃.The results also showed that the presence of the steel winding in the pipeline signiﬁcantly reduced the length of crack propagation up to 8.4 times,depending on the temperature effect and design parameters of *** work integrated the existing methods for crack localization along steel gas pipelines.

关键词： Crack propagation ﬁnite-element internal pressure prestressing steel gas pipeline temperature effect

来源：

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

Ectomycorrhiza of Larix sibirica Ledeb. along the gradients of main ecological factors and elevation at the Northern and Subpolar urals

引用

Journal of Mountain Science 2018年第12期15卷 2603-2613页

作者： SIZONENKO Tatyana Alexandrovna DUBROVSKIY Yuriy Alexandrovich institute of Biology of Komi Scientific Centre of the ural branch of the russian academy of sciences Russia SyktyvkarKommunistieheskaya str28Syktyvkar167000Russian Federation

Siberian larch(Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas(EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors(soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.

关键词： Ectomycorrhiza Larix sibirica Anatomy Fungal mantles diversity Elevation urals

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：