F34—Ⅰ型深部X射线治疗机固定照射野间照射量率的比值确定

测量了１２部Ｆ３４－Ⅰ型深部 Ｘ射线治疗机的照射量率，确定了固定照射野在 １５ × １０、１０ × ８、８ × ６、６ × ４单位ｃｍ×ｃｍ）情况下的照射量率比值：在空气介质中，源皮距为３０ｃｍ时，分别为１．０１５、１．０００、０．９７６、０．９５１以及源皮距为４０ｃｍ时，分别为１．０２６、１．０００、０．９７２、０．９４１；在水模体介质中，源皮距４０ｃｍ时，分别为１．１３６、１．０００、０．８７３、０．７３４。利用这些比值，可以快速准确计算出实际照射量率，为治疗恶性肿瘤提供准确可靠的剂量率值。     

含距离位势的拟线性椭圆方程解的存在性

变分原理证明了一类含距离位势的拟线性椭圆方程齐次Dirichlet边界条件下第一特征值问题的可解性.进一步,利用临界点理论得到了一类含距离位势的非线性椭圆方程非平凡解的存在性.     

Segregation characteristics of irregular binaries in gas solid fluidized beds—An ANN-approach

Binary mixtures of irregular materials of different particle sizes and/or particle densities are fluidized in a 15-cm diameter column with a perforated plate distributor. An attempt has been made in this work to determine the segregation characteristics of jetsam particles for both the homogeneous and heterogeneous binary mixtures in terms of segregation distance by correlating it to the various system parameters, viz. initial static bed height, height of a layer of particles above the bottom grid, superficial gas velocity and average particle size and/or particle densities of the mixture through the dimensional analysis. Correlation on the basis of Artificial Neural Network approach has also been developed with the above system parameters thereby authenticating the development of correlation by the former approach. The calculated values of the segregation distance obtained for both the homogeneous and heterogeneous binary mixtures from both the types of ftuidized beds （i.e. under the static bed condition and the ftuidized bed condition） have also been compared with each other.     

Generalized distance functions of Riemannian manifolds and the motions of gyroscopic systems

We use the homology groups of the path space of an arbitrary Riemannian manifold to define some analogs of the distance function and study their main properties. For the natural systems with gyroscopic forces we prove an existence theorem for solutions to the two-point boundary value problem, which complements the results of [1]. We apply the geodesic modeling method of [1, 2], using the generalized distance functions.     

On the distance function of a connected graph

An axiomatic characterization of the distance function of a connected graph is given in this note. The triangle inequality is not contained in this characterization.     

Radio number for trees

Let G be a connected graph with diameter diam(G). The radio number for G, denoted by rn(G), is the smallest integer k such that there exists a function f:V(G)→{0,1,2,…,k} with the following satisfied for all vertices u and v: |f(u)-f(v)|?diam(G)-d_G(u,v)+1, where d_G(u,v) is the distance between u and v. We prove a lower bound for the radio number of trees, and characterize the trees achieving this bound. Moreover, we prove another lower bound for the radio number of spiders (trees with at most one vertex of degree more than two) and characterize the spiders achieving this bound. Our results generalize the radio number for paths obtained by Liu and Zhu.     

Segregation characteristics of irregular binaries in gas solid fluidized beds——An ANN-approach

Binary mixtures of irregular materials of different particle sizes and/or particle densities are fluidized in a 15-cm diameter column with a perforated plate distributor. An attempt has been made in this work to determine the segregation characteristics of jetsam particles for both the homogeneous and heterogeneous binary mixtures in terms of segregation distance by correlating it to the various system parameters, viz. initial static bed height, height of a layer of particles above the bottom grid, superficial gas velocity and average particle size and/or particle densities of the mixture through the dimensional analysis. Correlation on the basis of Artificial Neural Network approach has also been developed with the above system parameters thereby authenticating the development of correlation by the former approach. The calculated values of the segregation distance obtained for both the homogeneous and heterogeneous binary mixtures from both the types of fluidized beds (i. e. under the static bed condition and the fluidized bed condition) have also been compared with each other.     

具有最小度距离的双圈图

记G（n）为所有n阶连通简单双圈图所构成的集合．本文主要讨论G（n）按其度距离从小到大进行排序的问题，并确定了该序的前两个图及其相应的度距离，其中具有最小度距离的图是由星图K1,n-1的一个悬挂点与另外两个悬挂点之间各连上一条边所得的图Sn．     

Carrier-envelope phase of ultrashort pulsed Laguerre-Gaussian beam

The carrier-envelope phase of the ultrashort pulsed Laguerre-Gaussian beam is studied.The order of Laguerre function affects seriously the variations of the carrier-envelope phase with the propagation distance increasing.The beam waist also affects the carrier-envelope phase in a few Rayleigh distances.The variation of the carrier-envelope phase is larger on the axis than on the beam periphery in propagation.     

某个单点值给定的Copula最优界的不可交换性度量

通过研究某个单点值给定的Copula(相关结构函数)的最佳上下界的不可交换性度量,构造了4个奇异的Copula,它们具有最大的不可交换性,揭示了最大不可交换Copula的结构特点和性质.定义了非径向对称和非联合对称意义下的随机变量的不可交换性,指出对于4个最大不可交换的C叩ula,3种不可交换性度量是相同的.另一方面,研究了在一般的Lp距离定义下的不可交换性度量的计算公式,确定了其中的标准化系数kp=3p 1(p 1)p 2/4,特别地k1=27/2和k2=81的计算公式可以作为常用的不可交换性度量.