A faster divide-and-conquer algorithm for constructing delaunay triangulations

An easily implemented modification to the divide-and-conquer algorithm for computing the Delaunay triangulation ofn sites in the plane is presented. The change reduces its (n logn) expected running time toO(n log logn) for a large class of distributions that includes the uniform distribution in the unit square. Experimental evidence presented demonstrates that the modified algorithm performs very well forn2¹⁶, the range of the experiments. It is conjectured that the average number of edges it creates—a good measure of its efficiency—is no more than twice optimal forn less than seven trillion. The improvement is shown to extend to the computation of the Delaunay triangulation in theL _p metric for 1<p.This research was supported by National Science Foundation Grants DCR-8352081 and DCR-8416190.     

65Mn钢CCT曲线及圆锯片淬火工艺

用全自动相变测定仪测定了圆锯片常用６５Ｍｎ钢的连续冷却转为曲线，研究了不同连续冷却速度下得到的组织，为合理制订圆锯片的淬火工艺提供了依据，得到了最佳淬火工艺曲线。     

Simulation of polycrystalline aluminum tensile test with crystal plasticity finite element method

The crystal plasticity was implemented in the finite element method（FEM） software ABAQUS through the user subroutine UMAT. By means of discretizing the space at the grain level with the Voronoi diagram method, a polycrystal model was built and used in the FEM analysis. The initial orientation of each grain was generated based on the orientation distribution function（ODF）. The developed model was successfully applied in simulation of polycrystalline aluminium samples deformed by the tensile tests. The theoretical strain--stress relation was in good agreement with the experimental result. The simulation results show that the grain size has significant effect on the deformation behavior. The initial plastic deformation usually occurs at grain boundaries, and multiple slip often results in an enhanced local hardening at grain boundaries.     

电缆化配电系统高频谐振频移方法

为解决电缆化配电网高频谐振问题,提出了一种基于配电网阻抗重构的高频谐振频移方法。首先,分析了电缆化配电网高次谐波源与高频谐振的产生机理。其次,给出了电缆化配电网阻抗重构的高频谐振频移方法,并比较不同无源阻抗重构后的频移及谐振峰抑制效果。然后,结合实际工程案例,利用系统函数绘出伯德图与根轨迹评价该方法对高频谐振治理效果以及系统稳定性的影响,验证了基于电缆化配电网阻抗重构的高频谐振频移方法的有效性,最后研究了无源阻抗参数变化对配电网高频谐振的影响。     

提高淬火模拟精度的系统化处理方法

为了提高淬火过程计算机模拟精度，提出了“系统化处理”方法。该方法以数学模型为基础。以试验结果为依据，根据冷却曲线和组织转变量用反计算方法求出数学模型中包含的材料和介质的物理参数，如热扩散系数、导热系数、相变潜热(相变温升)、扩散型相变动力学参数和热通量等。用标准探头测试热通量，其他参数用试验材料做成一个圆柱试样在淬火过程的两条或三条冷却曲线和不同半径上的组织转变量计算出来。该方法不仅可以获得计算中用到的物理参数。而且减小了计算误差。温度的最大计算误差约10℃，组织转变量的最大计算误差约10％。     

纱线烘干系统的PLC改造与应用

介绍了烘房烘干的工艺过程，及应用PLC在该系统中进行电气控制系统改造，使系统烘干质量高，工作可靠，设置、操作简单，提高了生产效率。     

Investigation of the titanium–indium system

The phase diagram of the Ti–In system was determined using DTA, XRD and EDX analyses. The existence of the phases Ti₂In₅ [Mn₂Hg₅ type structure, space group P4/mbm, a=0.99995(3), c=0.29960(2) nm] and Ti₃In [Ni₃Sn type structure, space group P6₃/mmc, a=0.5978(1), c=0.4812(1) nm] was confirmed. The phase previously labeled Ti₃In₂ was found to exist in a narrow homogeneity region near Ti₅₆In₄₄. Rietveld refinement of the XRD powder pattern yielded solutions compatible with a Cu₃Au-type or a BiIn-type crystal structure, but not with a CuAu-type crystal structure. Furthermore, at 38.5 at.% In, a new phase was observed having a γ-brass related crystal structure [Ti₈In₅, space group , a=0.99578(6) nm]. The intermetallic phases were formed by a cascade of peritectic reactions ending in a eutectic at >99 at.% indium between Ti₂In₅ and (In) at 0.4 K below the melting temperature of pure indium.     

纳米金属微粒二元相图的尺寸效应和形状效应

通过考虑相图计算公式中基本参数——熔化温度和熔化焓的尺寸效应与形状效应，研究了完全互溶的二元纳米金属微粒系统理想溶液的相图．研究结果表明，纳米微粒的相图也依赖于微粒的尺寸和形状因子．对Cr-Mo纳米微粒系统相图的计算结果表明，纳米微粒相图的固相线和液相线要比相应块体材料的固相线和液相线低，但与已报道的结果不同的是，固、液相线变化的幅度基本相同．这与本文目前不仅考虑了纳米微粒熔化温度的影响，还考虑了纳米微粒熔化焓的影响有关．     

铜在55%LiBr溶液中的电势-pH图

根据化学势绘制了室温下在55%LiBr溶液中CuBr-H2O体系的铜的电势-pH图和腐蚀-免蚀-钝化条件图.结果表明，水溶液中Br-离子浓度增大后，Cu2O的稳定存在区域明显减小，CuBr的生成电势负移，溶解电势正移，且其稳定存在区域明显拓宽，导致了铜的免蚀和钝化区域的缩小，腐蚀加剧.电势-pH图的建立对研究高浓度LiBr溶液中铜及其合金的腐蚀行为有一定的参考价值.      

Bi-Pb-Tl三元系相图

用室温、高温X射线衍射及淬火的方法,测定了Bi-Pb-Tl三元系25℃的等温截面及该体系中的相结构。