钪锆陶瓷粉体的制备及其热分析动力学

以Sc2O3,Zr(NO3)4·3H2O和NH3·H2O为初始原料,加入少量PEG400作为分散剂,采用化学共沉淀法,经反复水洗、醇洗和干燥后,制备了钪锆陶瓷粉前驱体。运用差示扫描量热/热重(DSC/TG)技术研究了前驱体在空气中脱水分解反应的动力学过程。DSC/TG分析结果表明:390 K附近的吸热峰,源于前驱体表面物理吸附水和乙醇的脱附;560 K附近的放热峰,源于前驱体表面的有机官能团被氧化剧烈放热;650 K附近较明显的放热峰,源于前驱体中氢氧化物的脱水反应;690 K附近较明显的吸热峰与前驱体晶型转变有关。用Kissinger法和Doyle-Ozawa法计算了前驱体脱水分解反应的活化能(E)分别为144.053和110.008 k J·mol-1。用Kissinger法确定了反应级数(n)和频率因子(A)分别为1.2和2.74×1011s-1,确定了前驱体脱水分解阶段的动力学方程为dα/d T=2.74×1011e-127030.456/RT(1-α)1.2。根据动力学研究的结果,采用优化的焙烧工艺制备了钪锆陶瓷粉。扫描电镜(SEM)和X射线衍射(XRD)分析表明,合成的陶瓷粉体具有类球形形貌,衍射峰峰形尖锐,没有杂峰,具有良好的立方相结构。     

二甲醚燃烧用催化剂BaO·MnO·6Al_2O_3的热分解动力学

采用反相微乳法制备和超临界干燥获得前驱体BaO.MnO.6Al2O3。利用TG-DTA曲线和XRD分析对前驱体的热分解过程进行研究,并用Coats-Redfern法和Kissinger法进一步研究前驱体的热分解动力学,获得六铝酸盐催化剂前驱体热分解的机制函数为:积分式G(α)=[-ln(1-α)]4,微分式为:f(α)=(1/4)(1-α)[-ln(1-α)]-3,反应为随机成核和随后生长控制,计算出的活化能Ea=187.80kJ.mol-1。     

八水碳酸镨的热分解及其动力学分析

采用碳酸氢钠和氯化镨制备八水碳酸镨颗粒后,运用TG-DSC技术,在不同程序升温下,研究八水碳酸镨(Pr_2(CO_3)_3·8H_2O)的热分解过程。分别采用Ozawa-Flynm-Wall法、Kissinger法、Crane法和Coats-Redfem法确定其热分解动力学参数。TG-DSC表明,八水碳酸镨热分解过程为3个阶段,第一阶段为脱水反应,第二阶段碳酸镨分解为Pr_2CO_5,第三阶段为Pr_2CO_5分解为Pr_6O_(11)。运用Coats-Redfem积分法得出第二阶段反应的反应机理受二维扩散机理控制,第三阶段反应的反应机理受成核和生长机理控制。在确定了八水碳酸镨热分解反应机理函数的前提下,实验计算得出三阶段反应的表观活化能E分别为47.24 kJ·mol~(-1)、220.94 kJ·mol~(-1)、120.71 kJ·mol~(-1);指前因子A分别为5.80×10~4 S~(-1)、1.35×10~(11) S~(-1)、6.22×10~2 S~(-1);第一阶段和第二阶段反应级数约为1,第三阶段反应级数为0.88。     

DIBK-P204体系萃取锆铪的热力学研究

以二异丁基甲酮(DIBK)为萃取剂,二(2-乙基己基)磷酸酯(P204)为改质剂,利用对数函数外推法对DIBK-P204体系从HSCN介质中萃取锆和铪的热力学进行研究,结果表明:锆铪与SCN-所形成配合物的一级稳定性常数分别为1×1010.07和1×10-0.12,DIBK-P204体系萃取锆和铪的热力学平衡常数分别为lg(K12,Zr)=5.00和lg(K12,Hf)=-4.69,焓变分别为ΔHZr=-13.76 kJ·mol-1和ΔHHf=-13.05 kJ·mol-1,说明对锆铪的萃取反应为放热反应,升高温度不利于萃取反应的进行,并计算出常温下萃取反应的自由能变分别为ΔGZr=-28.06 kJ·mol-1和ΔGHf=26.32 kJ·mol-1,熵变分别为ΔSZr=48.78 J·(K.mol)-1和ΔSHf=-134.30 J·(K.mol)-1。     

铈锆氧化物固溶体前驱物热分解动力学的研究

采用固相法制备了纳米级铈锆氧化物固溶体,对铈锆氧化物固溶体前驱物热分解动力学进行了研究。利用热重、差热分析等方法推测了前驱物的热分解机制。用Kissinger法计算前驱体的热分解活化能,Ea=137.80 kJ.mol^-1。通过Coats-Redfern法,采用不同的固相动力学反应机制研究前驱体的热分解动力学,确定其机制函数为：G（a）=[-ln（1-a）]1/2,判断前驱体热分解反应为随机成核-随后生长机制。     

六水草酸镝热分解过程机理及动力学研究

稀土草酸盐是目前制备稀土氧化物，尤其是制备具有可控粒度的稀土氧化物常用的前驱体，它具有沉淀物晶型好，易于过滤分解等优点.然而，目前稀土草酸盐热分解的动力学研究较少，因此，采用热重-差热分析法，研究六水草酸镝的热分解过程，通过Kissinger、Ozawa和Crane法计算六水草酸镝的分解动力学参数，通过Coats-Redfern法求出反应的机理函数.结果表明:几种方法计算的分解活化能比较接近，六水草酸镝热分解分2步进行，第1步为1级脱水反应，反应机理函数为F1，表观活化能为62.48 kJ/mol，指前因子为1.84×106；第2步也为1级分解反应，反应机理函数为F2，表观活化能为106.42 kJ/mol，指前因子为2.79×107.      

D001树脂静态吸附钕离子的热力学与动力学研究

为达到Nd3+富集目的,实验研究D001树脂静态吸附稀土Nd3+过程。通过单因素实验优化平衡吸附条件,并研究树脂吸附稀土Nd3+的热力学和动力学特征。结果表明:T=293 K,pH=3.5,[Nd3+]浓度10 mmol·L-1条件下,树脂的饱和吸附容量达到698.9×10-3mmol·g-1;吸附过程遵循Langmuir等温方程,热力学参数为:ΔH=13.45 kJ·mol-1,ΔS=53.035 J·mol-1·K-1,ΔG=-2.09 kJ·mol-1。热力学函数ΔG0表明D001树脂吸附Nd3+过程能够自发进行。准二级动力学模型能够很好拟合DO01树脂吸附Nd3+的过程并且其相关系数在0.99以上。吸附活化能Ea=1.04857 kJ·mol-1,反应控制步骤为膜扩散和颗粒内扩散联合扩散控制。     

十水草酸镧的热分解及其动力学分析

用热重-差热(TG-DTA)技术,在不同升温速率条件下,研究了十水草酸镧在空气气氛下的热分解过程.分别采用Ozawa-Flynm-Wall法、Kissinger法、Crane法和同步热分析法确定其热分解动力学参数.TG-DTA曲线表明:十水草酸镧分解为四个阶段,前两个阶段为脱水过程,后两个阶段为La_2(C_2O_4)_3的分解过程.实验计算得出四步反应表观活化能E分别为83.92、76.04、136.26、162.61 k J·mol-1左右;指前因子A分别为4.92×10~(10)、6.1×10~7、2.1×10~9、8.46×10~6s-1左右;反应级数n均为1左右,并用Coats-Redfem积分法得出第三步分解机理受F1控制.     

钪锆陶瓷粉的制备及其热分解动力学参数

以Sc2O3、Zr(NO3)4·3H2O和NH3·H2O为原料制备出了钪锆陶瓷粉。运用差示/热重(DSC/TG)、X-射线衍射(XRD)、扫描电镜(SEM)等手段,对钪锆陶瓷粉前驱体的热稳定性、相结构、表观状态及脱水动力学参数进行了分析。通过多重速率扫描法记录样品在不同升温速率下的DSC/TG曲线,采用kissinger法对钪锆陶瓷粉前驱体的热分解动力学进行研究。结果表明,钪锆前驱体为无明显晶形,400℃完成脱水反应生成钪锆陶瓷粉,486℃开始晶型转变为立方相,前驱体脱水反应的表观活化能E为99.62 kJ/mol,指前因子A为3.53×107,反应级数为1.2。     

十水草酸铈热分解过程和非等温动力学研究

用热重—差热分析法研究了十水草酸铈(Ce2(C2O4)3·10H2O)在程序升温下的热分解行为,TG曲线表明它有五个分解阶段,前三个阶段为脱水过程,后两个阶段为无水草酸铈热分解过程,最终产物为CeO2。对第四阶段无水草酸铈热分解为碳酸氧盐的过程进行了动力学研究,确定了其反应级数为2,表观活化能E=283.55kJ·mol-1,指前因子lnA=57.3119,热分解反应过程受F2机理控制。     

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.