螺旋线型微秒级高压长脉冲产生器数值模拟

 探索了采用CST软件和PSpice软件进行加速器场分布数值模拟的方法,利用该方法可方便地获取设备内部动态场分布图及动态电压变化规律。针对螺旋线型μs级高压长脉冲产生器系统建立了数值模拟模型,给出了详细的模拟步骤及结果。分析表明,利用场分布模拟方法获取的电压变化规律与电路模拟方法获取的结果是一致的。基于CST模拟方法,可以给出螺旋线及主开关等电气结构的瞬态电场分布,场强增强点主要出现在螺旋带的外沿及金属电极连接处,在介质支撑内部也有较高的场强分布。     

Circular Chromatic Indices of Regular Graphs

The circular chromatic index of a graph G, written line.com/cms/attachment/b8eced28-3674-452f-b3c6-e6a917170b57/jgt21757-math-0001.png">, is the minimum r permitting a function line.com/cms/attachment/95e8c4ae-4174-4aa3-ab75-2e177b840f78/jgt21757-math-0002.png"> such that line.com/cms/attachment/9f8bd726-1652-448b-aaa1-d9115e4bd25a/jgt21757-math-0003.png"> whenever e and line.com/cms/attachment/7f512663-e72b-4796-960a-41efb576af13/jgt21757-math-0004.png"> are adjacent. It is known that for any line.com/cms/attachment/abaefd28-623e-4fdc-adfc-57d40c1ad4dd/jgt21757-math-0005.png">, there is a 3‐regular simple graph G with line.com/cms/attachment/f56de7d1-60f2-488f-8ba9-c2ff871d296c/jgt21757-math-0006.png">. This article proves the following results: Assume line.com/cms/attachment/28d005c4-c98e-47d5-9d4a-795f06ec67b7/jgt21757-math-0007.png"> is an odd integer. For any line.com/cms/attachment/149c88f5-aabb-442d-b873-530921dd09b1/jgt21757-math-0008.png">, there is an n‐regular simple graph G with line.com/cms/attachment/c40ab64a-9b71-4989-a982-3e936383f1b9/jgt21757-math-0009.png">. For any line.com/cms/attachment/850532a2-c9b0-464b-8254-525e1a4adc2e/jgt21757-math-0010.png">, there is an n‐regular multigraph G with line.com/cms/attachment/d614ebc5-4369-41fb-8df1-420aed570920/jgt21757-math-0011.png">.     

Enhanced multi-Hoffmann heuristic for efficiently solving real-world assembly line balancing problems in automotive industry

In production systems of automobile manufacturers, multi-variant products are assembled on paced final assembly lines. The assignment of operations to workplaces and workers deter mines the productivity of the manufacturing process. In research, various exact and heuristic solution procedures have been developed for different versions of the so-called assembly line balancing problem.     

Spectrum created by line defects in periodic structures

We study a Helmholtz‐type spectral problem related to the propagation of electromagnetic waves in photonic crystal waveguides. The waveguide is created by introducing a linear defect into a three‐dimensional periodic medium; the defect is infinitely extended in one direction, but compactly supported in the remaining two. This perturbation introduces guided mode spectrum inside the band gaps of the fully periodic, unperturbed spectral problem. We will show that even small perturbations lead to additional spectrum in the spectral gaps of the unperturbed operator and investigate some properties of the spectrum that is created.     

带参数共轭梯度法簇的全局收敛性

共轭梯度法是最优化中最常用的方法之一,广泛地应用于求解大规模优化问题,其中参数β_k的不同选取可以构成不同的共轭梯度法.给出了一类含有三个参数的共轭梯度算法,这种算法能够在给定的条件下证明选定的β_k在每一步都能产生一个下降方向,同时在强Wolfe线搜索下,这种算法具有全局收敛性.     

用高中数学求解异面直线公垂线方程

用高中向量基础知识和待定法可非常方便地得出n（n≥3）维线性空间中异面直线的公垂线方程.若在大学数学教学中挖掘与中学数学的衔接和联系,则可在很大程度上降低大学数学的教学难度.     

A fast and efficient mesh segmentation method based on improved region growing

Mesh segmentation is one of the important issues in digital geometry processing. Region growing method has been proven to be a efficient method for 3D mesh segmentation. However, in mesh segmentation, feature line extraction algorithm is computationally costly, and the over-segmentation problem still exists during region merging processing. In order to tackle these problems, a fast and efficient mesh segmentation method based on improved region growing is proposed in this paper. Firstly, the dihedral angle of each non-boundary edge is defined and computed simply, then the sharp edges are detected and feature lines are extracted. After region growing process is finished, an improved region merging method will be performed in two steps by considering some geometric criteria. The experiment results show the feature line extraction algorithm can obtain the same geometric information fast with less computational costs and the improved region merging method can solve over-segmentation well.     

L（1, 2）-edge-labelings for lattices

For a graph G and two positive integers j and k, an m-L(j, k)-edge-labeling of G is an assignment on the edges to the set {0, 1, 2,..., m}, such that adjacent edges which receive labels differ at least by j, and edges which are distance two apart receive labels differ at least by kThe λ j,k-number of G is the minimum m such that an m-L(j, k)-edge-labeling is admitted by GIn this article, the L(1, 2)-edge-labeling for the hexagonal lattice, the square lattice and the triangular lattice are studied, and the bounds for λ j,k-numbers of these graphs are obtained.     

关于一个二重积分计算公式

约定f为连续函数,分别利用交换积分次序、变量替换、等位线法等三种方法证明二重积分计算公式∫0^a∫0^a f（x＋y）dxdy=∫0^a（a-t）f（t＋a）dt＋∫0^atf（t）dt,并得到一个类似公式∫0^a∫0^af（x-y）dxdy=∫0^atf（t-a）dt＋∫0^a（a-t）f（t）dt.