Managment and Optimization Model for Rangelands in Western China

Introduction The climatic characteristics of Northwestern China is dry with little precipi-tation and frequent wind flows, i. e. croncuced continental climate The annual rain-fall in most of the rangelands is between 250 to 600mm, majority of which are concen-trated in summer. This region is categorized as an arid desert grassland, or a semi-aridrange belt, or a semi-moist mountain rangeland Due to lack of scientific manage-ment policy as well as neglecting the ecological cycle of resource replenishment,     

Z—Transformation Graphs of perfect Matchings of Hexagonal Systems

A hexagonal system is defined to be a finit connected plane graph with no cut-vertices in which every interior region is surrounded by a regular hexagon of side length one.In the present paper we define the Z-transformation graph of a hexagonal system H to be the graph where vertices are the perfect matchings of (?) and where two perfect matchings are joint by an edge provided their symmetric difference is a hexagon of H.We prove that,if H has perfect matchings,Z(H)is a connected bipartite graph.Besides,Z(H)is either an elementary chain or a graph with girth 4.Some further results are obtained also.     

A Systematic Analysis of Human Activity on Landform Evolution of Loess Plateau——Taking loess plateau area in Gansu Province as an example

It is common knowledge that landform evolutionary process is controlled bytwo processes,endogenic forces processes,and exogenic forces process.Endogenicforces and exogenic forces processes history is as long as the earth's history.Comparing with landform evolutionary history,human history is a very shortinstance.But people have to undertake cultivation,animal husbandry and otherproductive activities for their living since they came to the world.This affectslandform evolutionary process.Especially,the effect of human activity on landformevolution of loess plateau is becoming more and more violent for several thou-sand years.Watersoil erosion is one of very important landform evolution pheno-menon of loess plateau.The authors have studied water-soil erosion of loess pla-teau area in Gansu province as example,analyzed the effect of human activity onwater-soil erosion.Thus the position and the effect of human activity on landformevolution of loess plateau have been shown from one point.     

一类0.1矩阵变换图的边连通性

Let U (R, S) denote the class of all m×n matrices of 0's and 1's havingrow sum vector R and column sum vector S. The interchange graph G (R,S)is the graph where the vertices are the matrices in U (R, S) and where twomatrices are joined by an edge provided they differ by an interchange. Brualdishowed that the connectivity of G(R, S) is at least two. In the present paperwe prove that the edge connectivity of G(R, S) is equal to the minimum degreeof vertices of G(R, S)     

关于复数阶蔡查罗求和法的求和因子

We say thatu_n is summable(C,a)to sum s,ifwherewhen a is a complex number,σ_n~a can be still defined as above.For Rea>0,Cesaro means(C,a)is regular.When I_ma_1I_m a_2,Re a_2>Re a_1>-1,any serieswhich is summable(C,a_1)is summable(C,a_2).If Rea_1=Rea_2,I_ma_1I_ma_2 and a_1,a_2-1,-2,…,it is known that there exists a series which is summable(C,a_1)but not summable(C,a_2).The object of this note is to find all convergence and summability factors inorder that the seriesu_k is summable(C,β)wheneveru_k is summable(C,a)a and β are any two complex numbers.For a real convex sequence{f_k},theproblems in the case a=0,β=iτ;a=1,β=1+iτ have been solved by volkof(3).I should like to discuss more general case for the generalized convex sequen-ce.We say that the sequence{f_k}is generalized convex,ifThe following theorems are proved.THEOREM 1.Let α,β be any two given complex numbers with 1>Re α=Re β>-1,I_m,αI_mβ and suppose that{f_k}is a generalized convex sequence.The neeesary and sufficieng condition forf_ku_k being summable(C,β)wheneveru_k is summable(C,α)is that f_n=0(1). THEOREM 2.Let α,β be any two given complex numbers with 1>Re α>max(Reβ ,1/2 R_e β—(1/2)),I_m αI_mβ,furthermore α,β-1,-2,…,and supposethat{f_k}is a generalized convex sequence.The necessary and sufficient conditionforf_k u_k being summable(C,β)wheneveru_k is summable(C,α)is thatTHEOREM 3.Let a and β be any two given complex numbers withand suppose that{f_k}is a generalized convex sequence.The necessary andsufficient condition foru_k being summable(C,α)wheneverf_k u_k is summable(C,β)is that|f_n|≥M>0for all n=0,1,2,…M-constant.THEOREM 4.Let α,β be any two given complex numbers withand suppose that{f_k}is a generalized convex sequence.The necessary andsufficient condition foru_k being summable C,α)wheneverf_ku_k is summable(C,β)is that|f_n|≥Mn~(Re(β-α))for all n=0,1,2,… M— constant.     

Matching Polynomials of Special Graphs

Farrell in [1] and Godsil and Gutman in [2] gave different definitions about matching polynomials ?? this paper we use the definition of [1] If G is a graph,m(G,i) will denote the number of matchings in G,i.e.,the number of selections of i independent edges of G.If i=0,We define m(G,0)=1.If G has n vertices,we call the polyrnomial ??? to be the matching polynomial of G.By ? we denote the complement of G obtained by deleting the edges of G from the complete graph ? denote the bipartite graph with bipartition m and n By ? we denote the bi-complement of ? obtained by deleting the edges of ?from ? (where ? is the complete bipartite graph with bipartition m and n).     

GAME THEORY AND ECOLOGY

In this paper,three kinds of application of game theory in ecology are dis-cussed and analyzed,conflict between species and nature,competition between ani-mal individuals,management of ecological environment,and the concept of thegame ecology,or ecology of games is defined.     

Energy Straggling Calculations Under IPM Potential

By using Bonderup and Hvelplund's formulation the energy straggling for light ions (such as H~+, He~(+2)) etc) in each element has been calculated based on the IPM potential. The results obtained in this paper not only reveal a Z_2 oscillation and energy dependence) but also give a single parameter IPM electron density function n(r) which is fitted by Hartree-Fock (HF) model. Merover, we suggest a very simple theory method for calculating energy straggling of a compound of a mixing matter with mean atomic number Z_2~* and adjustable parameter d~* except additivity rule, the results are in good agreement with recent experiments.     

Tchebycheff-Fourier 级数的Vall

The Approximation of f∈C［-1,1］ is discussed by V-P means of T-F series. The order of approximation and the expression of the error of approximation are obtained. The results of ［1］ and ［2］ have been improved.     

SOME PROPERTIES ABOUT DISTANCE DEGREE REGULAR GRAPHS

1. Introbuetion In paper [1], G. S. Bloom and others presented the concept of distance degree regular (DDR)graph, and discussed some fundamental properties about this class of graphs. In this paper, we mainIy consider the properties about graphical operations of DDR-graphs. In addition, we will give a class of DDR-graph having some special properties to demonstrate the variety and complexity of the structure of DDR-graphs. The graphs considered in the paper are all finite