水相介质中纳米CeO2的分散行为

通过测定悬浮液体系润湿性、表面电性及分散性研究了纳米CeO2在不同条件下水相介质中的分散行为.结果表明 纳米CeO2 在水相介质中的润湿与分散受体系pH值的影响很大, 与Zeta电位有相当好的一致关系, 其分散机理主要是双电层静电排斥作用; 纳米CeO2的等电点(pHPZC)为6.8左右; 纳米CeO2颗粒在酸性水介质中表面带正电, 在碱性水介质中表面带负电, Zeta电位分别在pH值为4和11左右时较高, 相应润湿性和分散性较好; 随机械搅拌速率和时间的增加, 纳米CeO2的分散性增强; 超声波对纳米CeO2的分散作用明显优于机械搅拌, 20 kHz频率下超声波分散1 min便能显著改善纳米CeO2的分散状态; 加入六偏磷酸钠(SHP)作为分散剂将改变纳米CeO2颗粒表面电性, 使其带负电, Zeta电位随SHP浓度增加而增大, 起增强双电层的静电排斥作用; 当SHP浓度达225 mg·L-1时, Zeta电位趋于稳定, 并使纳米CeO2在广泛的pH值范围内获得较高的Zeta电位和很好的分散效果, 从而降低了体系pH值的影响.     

氧化铝悬浮液稳定性的研究

通过改变球磨时间、分散剂用量对氧化铝悬浮液浆料的稳定性、分散性以及流变性进行了研究。结果表明：球磨时间和分散剂用量对氧化铝悬浮液的稳定性和分散性有着显著影响。最佳球磨时间在20h左右；纯氧化铝粉体的等电点在pH=8．1左右，分散剂的加入使等电点朝低pH方向移动，且可以显著改善浆料在碱性条件下的稳定性。     

纳米氧化铈在醇水混合溶液中的分散行为

通过沉降实验结合分光光度计、透射电镜等手段,考察了纳米氧化铈在不同比例醇水混合溶液(包括无水乙醇和纯水)中的超声分散性和悬浮稳定性;同时,测量了其在不同比例醇水混合溶液中的Zeta电位,并初步探讨了其分散机制。研究表明,随着醇水混合溶液中乙醇含量的减小,纳米氧化铈的超声分散性和悬浮稳定性均呈现出先升后降的规律;当乙醇含量为40%(体积分数)时,纳米氧化铈的超声分散性和悬浮稳定性均达到最好,其分散率为52.7%,且静置10天后的沉降率也仅为20.2%;此外,在该体系中纳米氧化铈保持其初始粒径的能力较强。纳米氧化铈在醇水混合溶液中的分散不遵守双电层理论,而与分散介质对颗粒的溶剂化作用有关。     

ZrO2悬浮液性能研究

采用乙醇为溶剂，PVB为分散剂和粘结剂，对固相的质量分数为55％的ZrO2悬浮液的制备和性能进行了研究。通过测定悬浮液的粘度和最终沉降体积，确定最佳分散剂含量。悬浮液的制备分两个阶段：第一阶段，悬浮液由ZrO2粉、乙醇和质量分数为0．7％的PVB(分散剂)组成，球磨24h，目的是打开颗粒团聚体和润湿粉料；第二阶段，主要是使悬浮液与粘结剂的混合，分别加入不同量的PⅦ(粘结剂)，球磨24h。结果表明，分散剂含量为粉体质量的0．7％时，能使ZrO2粉末得到良好的分散；当粘结剂含量少于6％时，在涂层坯体过程中容易出现裂纹；而粘结剂含量高于6％时，悬浮液中含有较多的气泡。加入0．7％分散剂和6％粘结剂，可以获得粘度适中、悬浮稳定的ZrO2悬浮液。     

粉体颗粒在空气及空气分级中分散性的研究进展

本文对粉体颗粒在空气介质中分散的研究进展进行了综述,并结合粉体颗粒在空气介质中发生团聚的原因介绍了几种评价粉体颗粒分散性的方法,最后概述了目前空气分级机中所采取的提高分散性的措施。     

氧化铝悬浮稳定研究

通过改变球磨时间、分散剂用量对氧化铝悬浮液浆料的稳定性、分散剂以及流变性进行了研究.结果表明:球磨时间和分散剂用量对氧化铝悬浮液的稳定性和分散剂有着显著影响.最佳球磨时间在20 h左右;纯氧化铝粉体的等电点在pH为8.1,分散剂的加入使等电点朝低pH方向移动,且可以显著改善浆料在碱性条件下的稳定性.     

羰基镍粉末悬浮液性能研究

湿法成型在降低粉体团聚、改善素坯显微结构均匀性方面有着明显的优势。本工作采用乙醇为溶剂 ,PVB为分散剂和粘结剂 ,对以固相含量为 55% (质量分数 )的羰基镍粉悬浮液的制备和性能进行了研究。包括 :通过测定悬浮液的黏度和最终沉降体积确定最佳分散剂含量 ;含有粘结剂的悬浮液分两个阶段制备 :第一阶段悬浮液由羰基镍粉、乙醇和 0 2 % (质量分数 )PVB(分散剂 )组成 ,球磨 2 4h ,目的是打开颗粒团聚体和润湿粉料 ;第二阶段主要致力于悬浮液与粘结剂的混合 ,分别加入不同量的PVB ,球磨 2 4h。结果表明 ,分散剂含量为 0 2 %(质量分数 ) (相对于粉体 )时能使羰基镍粉末得到良好的分散。当粘结剂含量少于 6 % (质量分数 )时 ,在涂层坯体过程中容易出现裂纹 ,而粘结剂含量高于 6 %(质量分数 )时 ,悬浮液中含有较多的气泡。含 0 2 % (质量分数 )分散剂 ,6 % (质量分数 )粘结剂时可获得黏度适中 ,能够稳定悬浮的羰基镍粉悬浮液     

激光辐照石墨-镍悬浮液制备碳包覆颗粒的研究

用球磨机湿法球磨微米级镍粉和石墨制备石墨与镍的悬浮液,然后用脉冲激光辐照.用扫描电镜、X射线衍射和透射电镜等对球磨和激光辐照后的产物进行表征.结果表明:球磨细化了镍粉,并使镍粉和石墨混合均匀,使其可悬浮于水介质中;然后激光辐照悬浮液得到了细小的碳包覆镍纳米颗粒.通过对碳包覆颗粒形成机制的初步探索,认为激光作用会使镍和碳气化并形成镍碳混合蒸气,在脉冲过后的冷却过程中碳和镍碰撞溶解,而温度的不断降低会促使过饱和的碳从镍中析出,从而形成包覆,获得了细小的碳包覆颗粒.     

表面改性CeO_2基抛光粉在水介质中的悬浮稳定性

CeO2基抛光粉在水介质中很容易沉淀,为提高CeO2料浆的抛光能力,氧化铈基抛光粉被表面改性。所用改性剂有六偏磷酸钠、十二烷基硫酸钠、十六烷基三甲基溴化铵、谷氨酸。用红外光谱分析仪、XRD、扫描电镜、激光粒度分析仪、Zeta电位、热重分析等对CeO2改性前后的物相组成、结构、颗粒大小、分散性、悬浮性和改性剂对CeO2的包裹率等进行表征,结果表明,阴离子改性剂十二烷基硫酸钠、阳离子改性剂十六烷基三甲基溴化铵和无机盐改性剂六偏磷酸钠能明显改善CeO2在水介质中的悬浮稳定性,两性离子改性剂谷氨酸对提高CeO2的悬浮稳定性的作用不明显;改性剂没有改变CeO2的物相组成和结构,仅粘附于CeO2的颗粒表面。CeO2悬浮液动力学试验表明,六偏磷酸钠对CeO2的黏附力最强,十六烷基三甲基溴化铵和十二烷基硫酸钠次之,氨基酸最弱。对玻璃材料的研磨试验结果表明,改性的CeO2颗粒(包裹体)有比较好的抛光效果,对玻璃材料去除率(MRR)的差异可能与改性剂的包裹率有关。在生产上,可以选用六偏磷酸钠作为CeO2基抛光粉的改性剂,且包裹率以不大于1.5%(质量分数)为宜。     

Al_2O_3-CeO_2-ZrO_2-Ni系球磨过程中的分散性和相变研究

运用XRD、SEM等方法研究了Al2O3-CeO2-ZrO2-Ni高能球磨体系在不同的球磨工艺条件下的组织结构转变和分散性的问题.结果表明,四种物质一起球磨时,不会发生机械合金化,但随着球磨时间的延长,Al2O3、CeO2、ZrO2粉末都会不断被细化,而Ni颗粒仍较粗大且分布很不均匀.通过改变球磨顺序,将CeO2、ZrO2和Ni先球磨30 h再添加Al2O3继续球磨30 h,却能使CeO2和ZrO2发生合金化生成固溶体,且Ni颗粒有明显的细化,分散性也明显提高.     

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)     

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.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.