PREPARATION OF SILVER POWDER FOR CONDUCTIVE PASTE

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Dynamic hardness of detonation sprayed WC-Co coatings

The objective of the present work was to determine the dynamic hardness of WC-Co coatings from the dynamic hardness of the coating substrate system. It was also the purpose of this work to evaluate the influence of coating composition, coating thickness, and substrate materials on the dynamic hardness of the coating. To achieve the above-mentioned objectives, WC-12%Co and WC-17%Co coatings were deposited by detonation spraying on three different substrate materials: mild steel, commercially pure (CP) aluminum, and CP titanium. The dynamic hardness of the coating/substrate composite was evaluated by a drop weight system. The dynamic hardness of the coating independent of the substrate was determined from the dynamic hardness of the coating/substrate composite.     

工业采暖锅炉中水煤浆喷嘴的失效分析

采用X射线能谱仪（EDS）、金相显微镜、扫描电镜（SEM）等设备对失效的水煤浆喷嘴的化学成分、微观组织及断口形貌进行了分析。结果表明，喷嘴材料中Ni含量偏低及高温渗硫所引起的S含量超标是导致喷嘴开裂的主要原因。同时提出了采用含钛铬镍奥氏体不锈钢及表面渗铝等相应改进措施以防止喷嘴失效。     

Biosorption behaviors of Cu~(2 ),Zn~(2 ),Cd~(2 ) and mixture by waste activated sludge

1Introduction Waste activated sludge is the by-product of sewage treated by activated sludge process.According to incomplete statistic,in China sewage discharge amount is4.474×107m3/d[1],and there are more than100sewage treatment plants with different sc…     

厚大断面球墨铸铁铁液石墨畸变倾向预测研究

通过考察不同厚大断面球墨铸铁铁液热分析曲线凝固段及其对应6h凝固组织间的关系,运用模式识别原理和数据库技术,提出了浇注前预测其石墨畸变倾向的方法。结果表明,热分析曲线凝固段综合偏差判据W值与6h凝固组织的石墨形态差异间存在明显收敛关系,当W趋于0时,6h凝固组织石墨形态的差别向0趋于收敛;当W足够小时,两条热分析曲线的差别也足够小,其对应的两种球墨铸铁铁液6h凝固组织中石墨形态的差别也足够小;待评估厚大断面球墨铸铁铁液的石墨畸变倾向可用与其热分析曲线形状最相近的另一铁液的6h凝固组织的石墨形态进行预测。     

离心铸造轧辊外层熔炼配料的优化

离心铸造轧辊生产中为了减少外层气体含量，要求尽量少脱硫降硅、甚至不脱硫降硅，为此根据外层材料成分的不同要求，在配料过程中采用不同的原材料及不同的配比，最终达到工艺要求。并介绍为达到工艺要求对所需各种原材料的化学成分要求。     

蚁群算法在铸造生产配料优化中的应用

以铸造配料成本最低为目标函数,建立了铸造优化配料数学模型.运用蚁群算法和Matlab语言,以ZG35Cr24Ni7SiN的炉料配比为例,对该数学模型进行了仿真优化计算,计算结果表明:在保证化学成分在控制要求成分的条件下,其吨钢成本比原手工配料方法节约550元,实现了铸造配料的优化配比,而且计算速度快于经典的线性规划数学方法,从而表明了蚁群算法应用于铸造生产配料是可行的.     

纳米氧化铝粉体的特殊液相沉淀法制备

本文通过液相反应胶粒析出机理分析，首次采用快速高强度机械混合液相沉淀法技术制备了小粒径(平均2nm)无定型氢氧化铝纳米粉体。经1250℃焙烧，获得α相纳米氧化铝。在制备过程中，采用适当的混合强度和反应液浓度可加强浆料过滤性，从而大大节省时间，得到小粒径高温相纳米氧化铝粉体。     

Method of calculating the collision integral and solution of the Boltzmann kinetic equation for simple gases,gas mixtures and gases with rotational degrees of freedom

The conservative method of calculating the Boltzmann collision integral for simple gases, gas mixtures and gases with rotational degrees of freedom of molecules is presented. In all cases the common approach based on the projection technique of summing up the contributions in the collision integral is used. The method is applied for solving the Boltzmann kinetic equation for two fundamental rarefied gas flow problems: the heat transfer problem and the problem of shock wave structure. A comparison with experimental and numerical data of other authors is reported. It is shown that the considered numerical method allows one to solve the Boltzmann equation for real gases with high accuracy.     

一种基于高斯混合模型的轨迹预测算法

在智能交通控制系统、军事数字化战场、辅助驾驶系统中,实时、精确、可靠的移动对象不确定性轨迹预测具有极高的应用价值.智能轨迹预测不仅可以提供精准的基于位置的服务,而且可以提前监测和预判交通状况,进而推荐最佳路线,已经成为移动对象数据库研究的热点,亟需设计准确而高效的位置预测方法.针对现有方法的不足,提出了基于高斯混合模型的轨迹预测方法GMTP,主要步骤包括:(1) 针对复杂运动模式利用高斯混合模型建模;(2) 利用高斯混合模型计算不同运动模式的概率分布,进而将轨迹数据划分为不同分量;(3) 利用高斯过程回归预测移动对象最可能的运动轨迹.GMTP是高斯非线性概率统计模型,其优势在于:计算结果不仅是位置预测值,更是关于移动对象未来所有可能运动轨迹的概率分布,可以利用概率统计分布特性获得某种运动模式(如匀加速运动)下的位置预测.大量真实轨迹数据集上的实验结果表明:与相同参数设置下的高斯回归预测和卡尔曼滤波预测法相比,GMTP的预测准确性平均提高了22.2%和23.8%,预测时间平均缩减了92.7%和95.9%.