人工神经网络在激光加工温度场模拟中的应用

研究了人工神经网络在激光加工温度场模拟用的参数推算中的应用方法；并设计了相应的BP神经网络模型及软件；研究表明BP神经网络适用于对激光加工模拟的参数推算，其准确性优于回归分析法和函数插值法。     

OPS和OPC系列稠油乳化降黏剂的研制

以工业品烷基酚聚氧乙烯醚OP-n（n=4,6,8,10,15）为起始原料,合成了烷基酚聚氧乙烯醚乙酸盐OPC-n和磺酸盐OPS-n两个系列的阴-非离子表面活性剂。以酸值和黏度不同的胜利单家寺和陈庄稠油为实验油样。将OPC-n和OPS-n溶于矿化度5811 mg/kg的胜利标准盐水和NaCl、CaCl2盐水中作为水相,按油、水质量比7∶3在50℃用玻棒搅拌混合,观察是否形成水包油乳状液并测黏度进行确认。在胜利标准盐水溶液中,OPC-n和OPS-n乳化稠油所需的最低质量分数,随稠油、表面活性剂类型及氧乙烯链节数n而变,一般而言,OPC-n系列中的OPC-8和OPS-n系列中的OPS-4乳化稠油的性能最好,该最低质量分数值分别为0.05%或0.025%和0.025%。在NaCl盐水溶液中,OPC-n的该最低质量分数值与稠油和n有关,均随盐含量增加而增大,在盐含量≤15%时,抗盐性最好的OPC-8和OPC-10的该值≤0.05%;OPS-n的抗盐性好于OPC-n。OPC-n的抗钙性良好,钙盐含量为2%时该最低质量分数≤0.1%;OPS-n的抗钙性更好,钙盐含量为2%和3%时该最低质量分数仅为0.025%或0.05%。表6参5。     

三维标量场并行等值面提取与绘制技术

通过研究并行等值面提取与绘制的各项关键技术要点,面向三维标量场的特点,在sort-last并行绘制模式的基础上提出一个三维标量场并行等值面提取与绘制框架.该框架在任务分配时采用静态分配的模式,在等值面提取时采用Marching Tetrahedra等值面提取算法,在并行绘制与场景合成时采用预先构建绘制节点控制模型的混合场景并行绘制合成算法.实验结果表明,该框架能够有效地提高大规模时变三维标量场的等值面提取与绘制效率,满足实际应用的需要.     

Group codes on certain algebraic curves with many rational points

We construct a series of algebraic geometric codes using a class of curves which have many rational points. We obtain codes of lengthq ² over _q , whereq = 2q ₀ ² andq ₀ = 2 ⁿ , such that dimension + minimal distance q ² + 1 – q ₀ (q – 1). The codes are ideals in the group algebra _q [S], whereS is a Sylow-2-subgroup of orderq ² of the Suzuki-group of orderq ² (q ² + 1)(q – 1). The curves used for construction have in relation to their genera the maximal number of GF _q -rational points. This maximal number is determined by the explicit formulas of Weil and is effectively smaller than the Hasse—Weil bound.Supported by Deutsche Forschungsgemeinschaft while visiting Essen University     

多水平外区抑制的轮廓检测

提取自然图像中的物体轮廓是机器视觉研究的重要问题,主要困难在于自然图像中的纹理性边缘严重干扰了物体轮廓的提取。研究表明视皮层方位选择性神经元的非经典感受野机制使得人类视觉系统在处理自然图像时不仅能够抑制纹理性边缘,而且能够增强物体的轮廓。基于此人们提出多种仿生轮廓检测算法,但算法中被称为抑制水平的参量在取值较高时会漏检部分轮廓,而在其取值较低时又会引入过多的纹理性边缘。针对这一问题,提出多水平外区抑制轮廓检测算法,通过整合各级单水平外区抑制的检测信息,有效抑制了纹理性边缘和降低了漏检轮廓的可能性。实验结果表明,相对于传统算法,新算法在轮廓检测性能上提高了10%左右,并具有更好的稳健性。     

Analytical and experimental analysis of deep drawing process for bimetal elements

The paper presents the concepts of solving of deep drawing process for bimetal elements of sheet materials. The inertia forces, plastic hardening behaviour of the deformed material and dynamic stress are utilized in the problems of plasticity. The experimental results and general conclusion are presented at the end of the paper.     

电、磁场对金属凝固组织的影响及应用

利用外加物理场凝固细晶技术是目前材料加工领域的研究热点。综述了各种电、磁场对金属凝固组织的影响，并对其主要的机理进行了探讨；并对电、磁场在金属凝固成形中的应用和进一步研究进行了展望。     

单道自动对接焊应变应力场分析

通过给出模拟单道自动对接焊过程的数学模型，用有元法计算瞬时应变场和应力场并与实测值进行比较，结果证实计算值与实测值基本吻合，表明用数学模拟自动对接焊过程是可行的。     

锌铝基合金陶瓷层激光重熔区的表面温度场

使用HSC 31快速扫描红外热像仪 ,测量了含Al2 O3 表层的锌铝合金激光熔覆时的表面温度场 ,测得熔池中最高温度为 16 72℃ ,边缘温度为 6 0 0～ 70 0℃ ,冷却速率为 2× 10 3 ～ 3× 10 4 ℃ /s以及熔池形状和等温曲线。     

Multivehicle coverage control for a nonstationary spatiotemporal field

This paper presents a multivehicle sampling algorithm to generate trajectories for nonuniform coverage of a nonstationary spatiotemporal field characterized by spatial and temporal decorrelation scales that vary in space and time, respectively. The sampling algorithm described in this paper uses a nonlinear coordinate transformation that renders the field locally stationary so that existing multivehicle control algorithms can be used to provide uniform coverage. When transformed back to the original coordinates, the sampling trajectories are concentrated in regions of short spatial and temporal decorrelation scales. For fields with coupled spatial statistics, i.e., the spatial decorrelation scales are functions of both spatial dimensions, the coordinate transformation is implemented numerically, whereas for decoupled spatial statistics, the transformation is expressed analytically. We show that the analytical transformation results in vehicle motion that preserves the vehicle sampling speed (which is a measure of vehicle speed scaled by the ratio of the spatial and temporal decorrelation scales), in the original domain; the sampling speed determines the minimum number of vehicles needed to cover a spatiotemporal domain. Theoretical results are illustrated by numerical simulations.