Brownian Dynamics Simulation of the Influence of Hydrodynamic Interaction on Particle Coagulation

采用布朗动力学模拟方法,研究了流体动力学作用对稀溶液中悬浮粒子聚集过程的影响.模拟中忽略了一个粒子同时与多个粒子碰撞聚集的可能,引入了前人有关两粒子间流体动力学作用影响的研究成果.模拟结果证实了流体动力学的作用在比较大的幅度上减缓了粒子的聚集过程,是导致粒子聚集速率的实验值低于Smoluchowski理论值的重要原因之一.另外,在分别加入和排除重力作用,以及考虑和忽略粒子间流体动力学作用在内的各种条件下模拟了粒子的聚集过程,得到了两种因素相互耦合作用时各因素对粒子聚集过程影响的结果,并从动力学的角度对这些因素的影响机制进行了相应的讨论

Effect of ZnO on Cu/ZnO/Al_2O_3 catalysts for methanol synthesis

[中文文摘]用高速碰撞共沉淀法制备m(CuO) /m(ZnO) /m(Al2 O3 )比分别为 60 /3 0 /1 0和 3 0 /60 /1 0的 1 #和 2 #催化剂 ,结果表明高ZnO的 2 #催化剂活性较好 ,分散度较大。XPS测试表明 2 #催化剂表面ZnO吸附的中间体 (CHx 或CHxO)较多且表面的Cu+1浓度较高 ,从而促进CO加氢合成甲醇的活性。[英文文摘]Cu/ZnO/Al_2O_3 catalysts with ratios of 60/30/10 and 30/60/10 have been prepared by high speed collision coprecipitation method. The performance of the catalyst with the higher ZnO content shows the higher activity in methanol synthesis. The characterization results indicated that the catalyst with the higher ZnO content has higher dispersion. On the surface of the higher ZnO content catalyst, there was more Cu+1 and more intermediate (CH_x and CH_xO) adsorpted. It is beneficial for the CO hydrogenating to produce methanol

Randomized Approximation Algorithm for MAX-CNF

已有的Johnson算法是求解组合问题的一种随机近似算法,可以用于求解MAX-CNF问题。基于该算法,提出新的随机近似算法RCNF求解MAX-CNF问题。概率推导和实验数值均表明,RCNF具有良好的近似比和稳定的性能。在构成难可满足问题的CNF实例上,将新算法与演化算法结合,进一步提出扩展算法E-RCNF。扩展算法利用演化算法的并行性,可以在较短时间内,简单有效地求出最多可满足子句数的近似值。Johnson's algorithm is a known randomized approximation algorithm for combinatorial problems including MAX-CNF problem.Based on it,this paper proposes a new algorithm RCNF,which has a steady performance and improves Johnson's algorithm on approximation ratio.On a class of instance of CNF,which constitutes hard-SAT problem,a further improvement is proposed which combines the RCNF algorithm with parallel evolutionary algorithm.Computational experiments show that this algorithm is faster and better than another given hybrid algorithm.“985工程”项目(0000-X07204)

求解MAX- CNF 问题的一种随机近似算法

已有的Johnson 算法是求解组合问题的一种随机近似算法, 可以用于求解MAX- CNF 问题。基于该算法, 提出新 的随机近似算法RCNF 求解MAX- CNF 问题。概率推导和实验数值均表明, RCNF 具有良好的近似比和稳定的性能。在 构成难可满足问题的CNF 实例上, 将新算法与演化算法结合, 进一步提出扩展算法E- RCNF。扩展算法利用演化算法的 并行性, 可以在较短时间内, 简单有效地求出最多可满足子句数的近似值。“985 工程”项目( 0000- X07204

Moving Object Detection Algorithm in Video Sequences

提出一种基于前景目标分类的视频序列中运动目标检测方法。该方法在RGB空间内建立了一种新颖的背景模型;为了解决背景更新“死锁”问题,提出了像素点的跳跃度函数和稳定性函数,将前景分类为静止目标、运动目标及虚假目标;最后提出了一种基于HSV颜色信息和一阶梯度信息的混合阴影剪除算法。实验结果表明,该方法能有效分割视频场景中的运动目标并鲁棒地分离目标及其阴影区域。An efficient algorithm of detecting moving objects in video sequences was proposed.An adaptive background model was built and subsequently the background model is updated by a foreground object classification based background update algorithm which can resolve the "deadlock" problem efficiently.An improved shadow suppression algorithm which combines HSV color information with first-order image gradient information was exploited to segment shadows.Extensive experiments results on indoor and outdoor image sequences demonstrate that the proposed system can effectively detects moving objects and suppresses their shadows.国家自然科学基金资助项目(60175008);; 国家创新研究群体科学基金项目(60024301

The effect of nurse initiated patient/family education strategy on people with schizophrenia in Beijing

2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Moving Object Tracking Based on Location and Confidence of Pixels

运动目标跟踪是视频信息处理的重要研究课题之一·首先将时间域上的中值背景建模与空间域上最小交叉熵法相结合,用于检测运动目标所在跟踪区域·在此基础上,提出了跟踪区域内基于像素的可信度与空间位置的权重函数,利用HSV色彩分布模型计算出目标模型与预测模型间的相似性,选出最优相似模型作为当前目标模型,从而实现了多目标的跟踪·实验显示,该算法计算简单,对相似目标能实现准确的跟踪,对非刚性目标的尺度变化、多目标的交叉及部分遮挡具有鲁棒性·Moving object tracking is a critical issue of image sequence processing. In this paper, a moving object tracking algorithm based on location and confidence of pixels is proposed. Firstly, the moving objects are detected by combining the median background model in temporal domain with the minimum cross-entropy in spa tial domain. Then the rectangle area of the objects are obtained, and at the sa me time an HSV color distribution model is used to measure the similarity betwe en t arget rectangles and hypothetical rectangles. In this process, a weighting func tion based on location and confidence of pixels is presented to weigh the pixel values in the rectangle area of the tracking. The experimental results show tha t the algorithm is computationally efficient and robust to scale invariant, part ial occlusion and interactions of non-rigid objects, especially similar objects .国家创新研究群体基金项目(60024301);; 国家自然科学基金项目(60175008

水声信道中彩色图像压缩编码及其DSP 实现

介绍一种适用于水声信道特殊情况下的彩色图像压缩编码方法,对在水声信道中完成对彩色图像的高速率 传输进行了初步的研究和尝试,并使用DSP 芯片来实现这种方法. 本文方法借鉴了”变球”彩色量化法,根据需要加 以改进成为符合要求的压缩编码方法. 使用MATALB 语言进行软件仿真查看效果,之后在CCS5400 软件平台上使 用DSP 汇编语言编程并编译、运行通过. 压缩后重建图像的质量很大程度上依赖图像本身的特点,因此重建后得到 图像质量水平不稳定,但是一些目前研究的图像进行试验之后得到的效果基本满意,故而这种方法有一定的实现意 义

城市建设中的土地污染和光污染的危害性与防治对策

【中文文摘】本文作者主要探讨了现在城市建设中往往被忽视的两种污染 ,即土地污染和光污染 ,指出了其危害性及防治对策。河南省科技攻关项目( 981140 2 10 )