检索结果-南通市图书馆

Some Limit Theorems for a Particle System of Single Point Catalytic Branching Random Walks

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2007年第6期23卷 997-1012页

作者： vladimir VATUTIN Jie XIONG Steklov Mathematical Institute Gubkin street 8 119991 Moscow Russia Department of Mathematics University of Tennessee Knoxville TN 37996 1300 USA Department of Mathematics Hebei Normal University Shijiazhuang 050016 P. R. China

We study the scaling limit for a catalytic branching particle system whose particles perform random walks on Z and can branch at 0 only. Varying the initial （finite） number of particles, we get for this system different limiting distributions. To be more specific, suppose that initially there are n^β particles and consider the scaled process Zt^n（·） = Znt（√n·）, where Zt is the measure-valued process 1 and to a representing the original particle system. We prove that Ztn converges to 0 when β 〈1/4 and to a nondegenerate discrete distribution when β=1/*** addition,if 1/4〈β〈1/2 then n-^（2β-1/2）Zt^n converges to a random limit,while if β 〉21then n^-βZtn converges to a deterministic limit.

关键词： Renewal equation branching particle system scaling limit

‘Relationships between relationships’ in forest stands: intercepts and exponents analyses

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2018年第3期29卷 575-582页

作者： vladimir L.Gavrikov Institute for Ecology and Geography Chair of Ecology and Environmental Studies Siberian Federal University

Relationships between diameter at breast height(dbh) versus stand density, and tree height versus dbh(height curve) were explored with the aim to find if there were functional links between correspondent parameters of the relationships, exponents and intercepts of their power functions. A geometric model of a forest stand using a conic approximation suggested that there should be interrelations between correspondent exponents and intercepts of the relationships. It is equivalent to a type of ‘relationship between relationships’ that might exist in a forest stand undergoing self-thinning, and means that parameters of one relationship may be predicted from parameters of another. The predictions of the model were tested with data on forest stand structure from published databases that involved a number of trees species and site quality levels. It was found that the correspondent exponents and intercepts may be directly recalculated from one another for the simplest case when the total stem surface area was independent of stand density. For cases where total stem surface area changes with the drop of density, it is possible to develop a generalization of the model in which the interrelationships between correspondent parameters(exponents and intercepts) may be still established.

关键词： Total stem surface area Self-thinning Conic approximation Power function Exponent Intercept Scots pine

Improved theory of generalized meteo-ballistic weighting factor functions and their use

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2016年第3期12卷 242-254页

作者： vladimir CECH Jiri JEVICKY Department of Weapons and Ammunition University of Defence Oprox Inc. Department of Mathematics and Physics University of Defence

It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire error budget *** calculated under non-standard conditions are considered to be *** tools utilized for the analysis of perturbed trajectories are weighting factor functions(WFFs)which are a special kind of sensitivity *** are used for calculation of meteo ballistic elements B(ballistic wind w B,densityρB,virtual temperatureτB,pressure p B)as *** have found that the existing theory of WFF calculation has several significant *** aim of the article is to present a new,improved theory of generalized WFFs that eliminates the deficiencies *** this theory will improve methods for designing firing tables,fire control systems algorithms,and meteo message generation algorithms.

关键词： Exterior ballistic Non-standard projectile trajectory Perturbation Meteoconditions Sensitivity function (Generalized) weighting (factor) function(curve) (Generalized) effect function Norm effect

Improved theory of projectile trajectory reference heights as characteristics of meteo-ballistic sensitivity functions

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2017年第3期13卷 177-187页

作者： vladimir Cech Jiri Jevicky Department of Weapons and Ammunition University of Defence Oprox Inc. Department of Mathematics and Physics University of Defence

Projectile trajectories calculated under non-standard conditions are considered to be perturbed. The tools utilized for the analysis of perturbed trajectories are weighting factor functions(WFFs) which are a special kind of sensitivity functions. WFFs are used for calculation of meteo ballistic elements mB(ballistic wind wB, virtual temperature tB, pressure pB, density rB, speed of sound a) as well. An effect of weapon system parameters can be incorporated into calculations through the reference height of *** are also calculated from WFFs. Methods based on RHT are far more effective than traditional methods that use weighting factors *** have found that the existing theory of RHT has several shortcomings due to we created an improved theory of generalized RHT which represent a special sensitivity parameters of dynamical systems. Using this theory will improve methods for designing firing tables, fire control systems algorithms, and meteo message generation algorithms.

关键词：灵敏度函数气象要素弹道风特征动力系统理论消防控制系统加权因子生成算法

Rationally connected varieties -On a conjecture of Mumford

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2017年第6期60卷 1019-1028页

作者： LAZIC vladimir PETERNELL Thomas Mathematisches Institut Universitat Bonn Bonn 53115 Germany Mathematisches Institut Universitat Bayreuth Bayreuth 95440 Germany

We establish a conjecture of Mumford characterizing rationally connected complex projective manifolds in several cases.

关键词： rationally connected varieties Mumford conjecture non vanishing conjecture abundance

Ecology and social behavior of the social vole Microtus socialis: A generalized review

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2023年第6期69卷 775-783页

作者： vladimir S.Gromov A.N.Severtsov Institute of Ecology and Evolution Leninsky prosp.33Moscow 119071Russia

The present review is a compilation of the published data on the ecology and social behavior of the social *** studies provide evidence that these voles live in family groups consisting of 1 adult male,1 or 2 breeding females,and their offspring(1 or 2 litters).The social vole is capable of year-round reproduction,but in arid regions,the voles demonstrate seasonality in *** mating system of this species may be defined as behavioral monogamy.A typical feature of the space use system is territoriality characterized by a locus-dependent dominance in relationships between neighboring breeding pairs as well as family *** family group social organization may be defined as consistent relationships without a dominant *** voles are cooperative in defending their territories,constructing burrows,digging underground tunnels,maintaining nests,and raising *** appears to enhance the survival of family groups of this species under the extreme climaticconditionsof Central Asia.

关键词： ecology family-group lifestyle mating system reproduction social organization social vole

Fragmentation model for large L/D (Length over Diameter) explosive fragmentation warheads

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

Defence Technology（防务技术） 2017年第4期13卷 300-309页

作者： vladimir M. Gold US Army RDECOM-ARDEC Attn: RDAR-MEE-F Picatinny Arsenal NJ 07806-5000 USA

New advanced numerical computer model enabling accurate simulation of fragmentation parameters of large Length over Diameter(L/D)explosively driven metal shells has been developed and *** newly developed large L/D multi-region model links three-dimensional axisymmetric high strain high strain-rate hydrocode analyses with the conventional set of Picatinny Arsenal FRAGmentation(PAFRAG)simulation *** standard PAFRAG modeling technique is based on the Mott's theory of break-up of idealized cylindrical"ring-bombs",in which the length of the average fragment is a function of the radius and velocity of the shell at the moment of break-up,and the mechanical properties of the *** the newly developed multi-region model,each of the shell region,the break-up is assumed to occur instantaneously,whereas the entire shell is modeled to fragment at multiple times,according to the number of the regions *** to PAFRAG methodology,the required input for both the natural and the controlled fragmentation models including the geometry and the velocity of the shell at moment of break-up had been provided from the hydrocode analyses and validated with available experimental *** newly developed large L/D multi-region PAFRAG model has been shown to accurately reproduce available experimental fragmentation data.

关键词： Explosive fragmentation modeling Natural fragmentation Mott model PAFRAG Fragmentation warhead lethality performance

The Impact of magnetic water treatment on salt distribution in a large unsaturated soil column

在线全文

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2017年第4期5卷 253-257页

作者： vladimir Zlotopolski United Research Labs San MarcosCAUSA

The use of saline water for crop production leads to soil ***-treated water(MTW)has been used for many years and has shown promise in leaching some ions from *** the same time,results have been inconsistent and somewhat *** this study,we used large unsaturated columns(diameter 15 cm and length 90 cm)to determine:1)salt distributions at depths of up to 90 cm after adding magnetically-treated,saline water to soil;2)whether MTW could reduce the rate of accumulation of salts(measured by EC)in soil,and;3)whether MTW could increase the leaching effect of soluble salts below root zones compared to *** soil tested had a lower salt content compared to the water,a real-world scenario often faced when farmers elect to switch from higher-cost municipal water sources to ground water sources that have a higher saline *** indicated that the rate of salt accumulation was greater in the control group at the 30–60 cm *** the same time,the salt content at the 90 cm depth was greater in the MTW *** results have shown that MTW changes the distribution of salts between soil layers reducing their content in the upper layers which are more important for agriculture.

关键词： Magnetic water treatment Agriculture Soil Irrigation water

Electron cooling experiments in CSR

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

Science China(Physics,Mechanics & Astronomy) 2011年第S2期54卷 274-278页

作者： PARKHOMCHUK Vasily REVA vladimir Budker Institute of Nuclear Physics

The six species heavy ion beam was accumulated with the help of electron cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). The ion beam accumulation dependence on the parameters of cooler was investigated experimentally. The 400 MeV/u 12C6+ and 200 MeV/u 129Xe54+ were stored and cooled in the experimental ring CSRe, and the cooling force was measured in different conditions.

关键词： heavy ion beam beam accumulation electron cooling cooling force