镍包覆铜复合粉末的化学镀制备工艺研究

研究了用联胺做还原剂,通过化学镀制取镍包铜基复合粉末.试验选取了6个主要参数,并以此设计了L25(56)型正交试验.通过实验,优化工艺参数为硫酸镍初始质量浓度:30g/L,联胺初始质量浓度:70ml/L,pH值:13,镀覆温度:82℃,铜粉加载量:15g/L,保温时间:35min.采用SEM(包括EDS)、XRD对选用上述参数制取的镍包铜粉进行了分析测试.结果表明,复合粉末表面较原始粉末粗糙,颗粒明显长大,包覆层未引入杂质元素,并对所得粉末进行化学及工艺性能测试,表明所得的复合粉末,性能指标优良.     

镍包覆铜复合粉末烧结体界面扩散行为研究

利用固相烧结法将镍包铜粉成功地制成了块状烧结体,通过SEM、XRD和EDS研究了烧结过程中镍包铜粉中界面的迁移情况.结果表明,随烧结温度升高,颗粒内原子扩散系数越大,烧结体界面迁移越容易,形成较大的晶粒,同时界面组织也比较均匀.在扩散过程中,由于镍的扩散系数比铜大,镍层扩散进入铜形成了铜镍固溶体,界面呈现单向迁移.     

Bc介子非轻子两体衰变

计算Bc介子非轻子两体衰变Bc→X＋Y，末态强子之一X是P波Xc态或hc态 过程的衰变宽度。强子跃迁矩阵元写成形状因子的形状，形状因子表示初态末态介子波函数的重叠积分，介子波函数采用势模型理论求得。     

A novel maneuvering multi-target tracking algorithm based on multiple model particle filter in clutters

To solve the problem of strong nonlinear and motion model switching of maneuvering target tracking system in clutter environment, a novel maneuvering multi-target tracking algorithm based on multiple model particle filter is presented in this paper. The algorithm realizes dynamic combination of multiple model particle filter and joint probabilistic data association algorithm. The rapid expan- sion of computational complexity, caused by the simple combination of the interacting multiple model algorithm and particle filter is solved by introducing model information into the sampling process of particle state, and the effective validation and utilization of echo is accomplished by the joint proba- bilistic data association algorithm. The concrete steps of the algorithm are given, and the theory a- nalysis and simulation results show the validity of the method.     

Co基非晶合金形成能力与磁学性能研究

采用单辊快凝法制备出了Co73Si1OB17非晶材料,研究了其非晶形成能力与磁学性能,应用X射线衍射（XRD）、透射电子显微镜（TEM）对条带的显微结构及非晶化程度进行了分析,用示差热分析法（DTA）测量了台金的玻璃转变温度和晶化温度,用振动样品磁强计（VSM）测量了合金的静态磁学性能,实验结果表明,在所研究的合金成分范围内和单辊快淬工艺条件下,钴基合金的非晶态形成能力大,制备非晶薄带较容易,Co73Si10817非晶态合金具有较高的热稳定性,DTA曲线上有一个明显的吸热峰和两个明显的放热峰,合金的玻璃转变温度（Tg）为715K,合金的初始晶化温度（Tx1）为753K,第二个晶化温度（Tx2）为823K,因而合金的过冷液相区△T=Tx1-Tg=38K。Co73Si10817非晶合金具有优异的软磁性能,饱和磁感应强度（Bs）为1.04T,功率损耗（W）、剩磁（Bt）与矫顽力（Hc）为零。     

计算机自校正多点温度测控系统

计算机技术为提高测控系统的精度提供了新手段.我们研究了用软件修正测量误差的方法,并把它用在多点温度测控系统中.此系统已于1984年11月用于广西玉林自行车一厂,对四个烤漆炉同时实现温度的监测与控制.它克服了目前国内一直沿用的人工测控的检测精度不高、温度控制不稳定以及产品质量难以保证等缺点.该系统的主要功能是:1.可按工艺要求对温度在40～350℃之间的四个烤漆炉进行温度的自动检测与控制;2.能获取给定热源分布下炉内温度的数据,以提供合理调整热源分布的方案;3.能得到各烤漆炉在不同的环境温度下炉内温度随时间的变化情况,以提供合理利用能源的     

CO和O_2在钙钛矿型LaCoO_3表面化学吸附的EHMO研究

本文用EIIMO方法,计算了CO和O_2在钙钛矿型LaCoO_3表面不同位置的吸附能,据此确定了它们的吸附位置和构型,并推测了CO在此催化剂上催化氧化的机理,认为在低温区,主要是吸附态O_2与CO反应,而在高温区,CO与晶格氧反应占支配地位。     

Geochemical significance of the relative enrichment of pristane and the negative excursion of δ^13CPr across the Permian-Triassic Boundary at Meishan, China

Changes in the distribution of isoprenoid hydrocarbons and in δ^13Ckero or δ^13Cpr across the section from the Changxing Formation to the lower Yinkeng Formation at Meishan （the GSSP of PTB） are studied, in which a relative enrichment of pristane and a sharp shift in both δ^13Ckero and δ^13Cmole near the boundary are revealed. A possible mechanism for the abnormal accumulation of pristane near PTB is suggested： Lipids in some marine animals and their metabolites, rich in pristane, can be preserved and accumulate in some suitable depositing facies under certain special conditions, such as the catastrophic death of animals and/or developing of an anoxic water column, and thus the pristane enrichment occurs in the sediment. The occurrences of isoprenoid enrichment and high Pr/Ph ratios have been found in other typical marine anoxic sediments accompanied by mass extinction in various extent during the most important geological periods, such as Late Ordovician, end of Devonian, Early Jurassic and Late Cretaceous. These occurrences support to a certain extent the above mechanism that interprets the genesis of a high Pr/Ph ratio in some typical marine anoxic sediments. The synchronous sharp negative shifts in δ^13Cmole, δ^13Ckero and δ^13Ccarb from Beds 24 to 26 of the Meishan profile indicate that a sudden and strong variation of carbon source in the atmosphere-ocean system occurred during the quick but equable evolution from the end-Permian to Early Triassic, and the coupling between the pristane enrichment and negative shift in δ^13Ckero and δ^13CPr may well indicate the importance of the release of methane hydrates and marine anoxia in the end-Permian mass extinction.     

自熔合金粉末性能对喷焊涂层组织的影响

利用扫描电镜SEM和X射线衍射仪分析研究了自熔合金粉末颗粒内部形貌和夹杂物对涂层组织的影响.结果表明,在空心粉率相同的情况下,空心粉末中气泡在中心形成,内部壁厚均匀且较厚的粉粒比颗粒内部气泡出现偏移或开口的粉粒更易产生喷焊涂层微观缺陷(针孔);粉末颗粒内部存在着少量金属Cr夹杂,由于夹杂物表面生成了保护性氧化膜,喷焊时夹杂物不能溶解到基体中,涂层在进行磨削加工时出现剥离,形成不规则状缺陷.     

估算单辊甩带法制备镁基非晶薄带的冷却速度

临界冷却速度是表征非晶态合金非晶形成能力的一个重要参数,但是正确地测量和估算非晶态合金形成时的冷却速度却十分困难.结合热传导理论和凝固理论,单辊甩带过程的热传输可以用一维傅立叶热传导方程描述.通过对热传导方程的数学解析求解,具体计算了单辊甩带法制备镁基非晶薄带的冷却速度,得到了铜辊制备50μm厚镁薄带的自由侧在凝固结束时的冷却速度为5.84×106K/s,这与早期人们预测的单辊甩带法的冷却速度相当.