催化动力学光度法分析茶叶中微量硒

采用催化动力学光度法对茶叶中硒的含量进行了分析测定.在硝酸介质中,硒(Ⅳ)催化溴酸钾氧化亚甲蓝产生褪色,以此建立了催化动力学光度法分析微量硒的方法.探讨了动力学反应条件,并对茶叶样品分析的前处理过程进行了研究.实验结果:硒的浓度在0~8μg/L范围内,lg(A0/A)与浓度C之间呈良好的线性关系;方法的回收率为93%~106%,相对标准偏差小于0.302 2%,方法的准确度与精密度较好,适用于茶叶中微量硒的分析.     

篮球教学和训练中运动损伤成因与预防措施

采用文献资料法、实践观察法以及伤者访谈法,对在篮球教学和训练中引起损伤的原因进行分析,提出了一系列预防运动损伤的相应措施。建议在篮球课教学和训练中要强化学生预防运动损伤的意识,加强体育保健指导,尽量减少或避免运动损伤的发生。     

一级反应速率常数测定数据处理方法选择

讨论了具体确定一级反应速率常数的方法：传统的积分法、微分法、Guggenheim法。传统的积分法需要测定反应完全时的物理量k，但数据处理简便，结果较好；微分法和Guggenheim法均不需测λ∞，但微分法数据处理较复杂，且要求测定的时间间隔愈短，结果才愈好；Guggenheim法数据处理简便，但适用于半衰期较短的反应，结果才满意。     

雅可比坐标在多粒子体系中的应用

推导得出了Hamilton量中动能算符的雅可比坐标表示,并以求解双原子分子的能谱为例,详细讨论了雅可比坐标在多粒子系统中的应用。     

催化动力学光度法测定痕量钛

在HCl-NaAc(pH=0.90)酸性介质中,以钛催化过氧化氢氧化苯基荧光酮为指示反应,建立了一种催化动力学光度法测定痕量钛的新方法,并尝试用于测定大米、头发中的痕量钛(Ⅳ)。结果表明,在实验确定的最佳条件下,该方法的最低检出限为2.61×10-6 g/L,相对标准偏差为2.05%,测定的线性范围为(0.01～0.08)mg/L,结果令人满意。     

水电站运行低水位的选择探讨

结合从事《水电站》教学经验和承担小型水电站设计工作,从动能经济效益和水轮机安全经济运行等方面综合分析、探讨如何合理地选择水库电站运行最低水位。     

不同参考系中的功和动能定理

功和动能定理在求解相关的物理问题时有着重要作用，在不同的参考系中计算的功值是不相同的．其差值决定于运动物体在这一运动过程中的动量增量与两系相对速度的乘积．在不同的惯性系中质点的动能定理有着相同的形式．质点系内力所作的功在不同的惯性系中也是相等的，其功值的大小与参考系的选择无关，在非惯性系中应用动能定理应当考虑惯性力所作的功．结论才是正确的，     

运动干预对2型糖尿病治疗效果的影响

对98例门诊2型糖尿病病人在其他治疗措施不变的情况下,采取运动干预,对运动干预前后血糖控制有效率进行比较,差异具有显著意义(P＜0.05).说明积极有效的运动干预可以有效降低血糖并提高其他治疗方法对控制血糖的作用.     

Study on the serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) in patients with Helicobacter pylori Infection

Objective: To evaluate the interaction between serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and Helicobacter pylori (H. pylori) infection in patients with chronic gastritis and peptic ulcer. Methods: The serum levels of sICAM-1 in 205 patients with chronic gastric diseases were detected by ELISA method and the status of H. pylori was determined by histologic examination, RUT, 14C - UBT, and serology. The sera obtained from 18 healthy volunteers served as controls. Results: The serum levels of sICAM-1 were significantly higher in patients with H. pylori positive than those of H. pylori negative (889.43±32.52 ng/ml vs. 747.07±30.45 ng/ml, P<0.05). The serum levels of sICAM-1 in patients with mild, moderate and severe infection of H. pylori were 841.68±72.36 ng/ml, 905.43±37.59 ng/ml and 1012.54±49.34 ng/ml,respectively (P<0.05). The serum levels of sICAM-1 proved to be significantly correlated with the density of H. pylori colonization in gastric mucosa (rs =0.316, P<0.001). The serum levels of sICAM-1 in patients with chronic gastritis and peptic ulcer were significantly higher than those in healthy controls (P<0.05). Conclusions: These results indicated that H. pylori infection up-regulates the expression of sICAM-1.     

7-lump kinetic model for residual oil catalytic cracking

INTRODUCTION Residua catalytic cracking (RCC) is a process in which crude oil fractions are cracked into more valuable lighter products in a riser reactor with flu- idized catalyst. The complexity of charge stocks make it extremely infeasible to characterize and de- scribe at a molecular level, so attempts have been made to lump large numbers of chemical compounds into a kinetic species to describe the complex reac- tions in the process (Wei and Kuo, 1969; Kuo and Wei, 1969). Some early…