基于曲面响应法的大气等离子喷涂La2Ce2O7涂层粒子特性与微观结构研究

根据Box-Behnken曲面响应法，利用Design Expert软件设计了大气等离子喷涂三个工艺参数（电流I、氩气流量、氢气流量）的三水平回归分析试验，通过SprayWatch-2i系统在线测试La₂Ce₂O₇粒子飞行速度及表面温度，经统计分析得到粒子温度和速度的回归模型。采用扫描电镜表征涂层微观结构，并利用Image-Pro-Plus图像分析软件计算未熔颗粒面积分数和孔隙率。结果表明，La₂Ce₂O₇粒子速度符合线性模型，电流、氩气流量是影响粒子速度的主要因素，而氢气流量对粒子速度的影响不显著。粒子速度随氩气流量和电流增大而线性增长。当氩气流量为120 L·min–1，电流为600 A，氢气流量为10 L·min–1时，粒子速度达到最大。粒子温度符合二次模型，氩气流量、电流以及两者之间的相互作用是影响粒子温度的最主要因素。当氩气流量为74.22 L·min–1，电流为543.96 A，氢气流量为10 L·min–1时，粒子温度达到最大。粒子熔化状态提高，涂层未熔颗粒下降。     

无限深球方势阱中单粒子量子比特的性质

本文利用求解能量本征方程方法,研究了无限深球方势阱中单粒子的能级结构和量子比特的性质.理论推导和数值计算表明,无限深球方势阱中粒子的能量随球半径的增大而减小;量子比特的振荡周期由粒子质量和球半径决定,且随球半径的增大而增大;量子比特内粒子的概率密度随空间坐标的变化而变化,各空间点的概率密度均随时间做周期性振荡.     

单一煤粉粒子燃烧的直接观察

在层流炉内试验煤粉粒子燃烧时，利用高速摄像机观察煤粒子燃烧，用图像分析观测煤粉粒子周围的温度分布，以此说明喷吹到高炉内的煤粉粒子燃烧的基本原理。由于挥发分的燃烧，着火后发现煤粉粒子周围有一个火焰，其火焰的直径是由氧含量及煤种决定的。基于这些结果，所观察到的煤粉粒子火焰面位置以及通过挥发分燃烧得到的热源，影响到燃烧率。此外，在高炉内大量喷吹煤粉时，煤粉粒子分散情况以及煤粉粒子周围的氧含量，对燃烧率有明显的影响。     

一种改进的人工蜂群算法——粒子蜂群算法

针对经典人工蜂群算法收敛速率较慢,后期易陷入局部最优解的不足,本文将粒子群算法中"全局最优"的思想引入到人工蜂群算法的改进过程,从而形成了一种新的人工蜂群改进算法——粒子蜂群算法.首先,提出了趋优度的概念,用来衡量引领蜂在有限次迭代过程中向全局最优解靠近或远离的程度,趋优度值可以评价个体的"发展潜力",趋优度值越低的个体,越需要增大变异的程度,以便找到质量更优的解.其次,专门设计了一种新的蜜蜂群体——粒子蜂,在引领蜂变异阶段根据趋优度的大小将引领蜂变异为侦查蜂和粒子蜂,粒子蜂的出现在很大程度上增加了种群的多样性,拓展了算法的搜索范围.然后,通过粒子蜂群算法种群序列是一个有限齐次马尔科夫链和种群进化单调性的分析,验证了本文所提算法的种群序列依概率1收敛于全局最优解集.最后,将本文所提算法应用于多个常见测试函数,并与经典蜂群算法、近年其他文献改进蜂群算法进行了仿真对比研究,仿真结果表明本文所提算法确实加大了种群的分散度、扩宽了搜索范围,从而具有更快的收敛速度和更高的寻优精度.      

等离子体熔化离心雾化喷涂粒子的特性

研制了一种基于离心雾化原理的内孔热喷涂设备，简要介绍了该设备的工作原理和粒子的雾化过程。对试验收集的雾化粒子进行了观察与统计分析，用扫描电镜观察了雾化粒子的表面形貌，并统计分析了消耗电极在不同转速下的粒子粒度及其分布。结果表明，雾化粒子的球形度较好，粒度较均匀。还研究了消耗电极转速和直径的变化对粒子粒度以及粒度变化率的影响。分析表明：提高消耗电极的转速和直径会使粒子的粒度减小；但是，当电极转速和直径增大到一定程度后，继续增大这2个参数对粒子直径变化的影响将大大减小，说明存在一个最佳的消耗电极转速和直径范围，在此范围内设备稳定性和喷涂粒子直径都可以达到最佳。     

Au核@Pt壳纳米粒子的光化学还原法合成及表征

在柠檬酸钠-丙酮-乙醇体系中采用光化学还原法同时还原或连续还原Au(III),Pt(IV)离子,合成了Au核@Pt壳复合纳米粒子。采用X射线光电子能谱(XPS),UV-Vis,透射电镜(TEM)等分析手段对两种方法合成的复合粒子的结构、形貌等进行了对比分析,并对复合粒子核壳复合结构的光化学形成机制进行了讨论。研究表明:两种方法均可合成颗粒比较均匀、具有良好单分散性的Au核@Pt壳复合纳米粒子,其平均粒径5.1~10.2 nm;其中,同时还原法制备的复合纳米粒子的平均粒径相对较小是5.1~8.1 nm,而当n(Au)∶n(Pt)=1∶4时,粒径最小,为5.1 nm。同时还原和连续还原法所制备的胶体粒子的UV-Vis吸收光谱与Au,Pt简单混合胶体的有明显不同,双金属复合胶体粒子的UV-Vis吸收光谱中Au的特征共振吸收强度明显下降并且蓝移,下降程度远大于其浓度的降低,且随着粒子中Pt元素含量的进一步增加,Au的特征吸收峰最终消失而只体现Pt的吸收光谱,这表明同时还原和连续还原Au(III),Pt(IV)离子所制备的胶体粒子为双金属复合粒子,复合粒子结构中Au元素存在于粒子内部,Pt元素存在于粒子表面,即两种还原方式所制备的双金属复合粒子具有Au核@Pt壳复合结构。     

对流动粒子炉的研究

本文给出了流动粒子炉的定义和分类,叙述了对煤气流动粒子炉、电流动粒子炉、冷却用流动粒子炉,粒子层内的传热,以及流动粒子换热器等的研究工作。介绍了研究的结果和研究的方向。一、流动粒子炉的定义近十年来流态化技术在冶金、机械和仪表工业的热处理中得到广泛地应用和推广,已逐渐形成为一种独特的金属加热和冷却的设备,即流动粒子炉或流态粒子炉、沸腾粒子炉。它不同于一般化学工业,冶金工业以及其它工业所使用的流化床设备,如沸腾焙烧炉,流态化干燥设备等,而具有特殊的效能和用途。可以从流态化床的种类中独立出来,     

含离子液体介质中铜纳米粒子的制备及其影响因素

在含有离子液体[BMIm]PF6、[PMIm]PF6和[C6MIm]PF6的介质中,通过还原Cu2+制备铜纳米粒子.通过TEM和XRD分析,对比研究了Cu2+浓度、还原剂种类以及离子液体[BMIm]PF6、[PMIm]PF6和[C6MIm]PF6对所制备的铜纳米粒子的粒径和形貌的影响.结果表明:Cu2+浓度对铜纳米粒子的粒径和形貌没有明显的影响;离子液体的类型对铜纳米粒子的粒径也没有明显的影响,但对形貌有一定的影响;还原剂对铜纳米粒子的粒径及形貌影响较大.     

层流炉内单一煤粉粒子燃烧的直接观察

在层流炉内试验煤粉粒子燃烧时，利用高速摄像机观察煤粒子燃烧，用图像分析观测煤粉粒子周围的温度分布，以此说明喷吹到高炉内的煤粉粒子燃烧基本原理，由于挥发分的燃烧，着火后发现煤粉粒子周围有一个火焰，其火焰的直径是由氧含量及煤种决定的。基于这些结果，所观察到的煤粉粒子火焰面位置以及通过挥发分燃烧得到的热源，影响到燃烧率，此外，在高炉内大量喷吹煤粉时，煤粉粒子分散情况以及煤粉粒子周围的氧含量，对燃烧率有明     

TiN粒子在焊接热循环过程中的溶解、粗化及再析出行为

采用萃取复型技术,对经受焊接热循环不同阶段的试样进行研究,分析TiN粒子在焊接热循环不同阶段的溶解、粗化及再析出行为。结果表明,在焊接热循环加热过程的低温阶段（1200℃以下）,粒子的溶解以粒子的尺寸减小为主要特征,粒子数量变化不大。在焊接热循环加热过程的高温阶段（1200-1350℃）,大量小尺寸粒子消失,粒子平均尺寸显著增大。研究发现,TiN粒子的溶解存在很大的滞后效应,在冷却过程的高温阶段（1350-1300℃）,粒子仍继续溶解,在冷却过程的低温阶段（1300℃以下）,固溶状态的Ti与N结合并沉淀到残留的TiN粒子上,使粒子粗化。在焊接热循环过程中,Ti微合金钢原始奥氏体晶粒长大主要发生在冷却阶段。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.