火焰原子吸收光谱法测定Mn3O4 产品中钙镁含量

用盐酸加热溶解四氧化三锰样品, 加入镧盐和锶盐混合释放剂, 消除70%左右基体锰的干扰, 直接测定其中钙、镁含量, 样品加标回收率为96.8%~ 98.2%,相对标准偏差为2.4%~3.2%.     

Gastrointestinal transit and digestibility of maltitol,sucrose and sorbitol in rats: A multicompartmental model and recovery study

Using data obtained with a dye marker and the gavage technique, the kinetics of gastrointestinal transit of different loads of sugar substitutes (maltitol, sorbitol) and sugar (sucrose) in the rat were analysed using a linear multicompartmental model over a range from the realistic to the non-physiologic high, of carbohydrate intake levels and using only a few experimental time points. The model gave detailed insight into intestinal propulsion and gastrocecal transit time. Rate constants of transport between the compartments investigated were determined; they showed characteristics which could be related to the substance and the dosage administered. Analyses of the gastrointestinal content and calculations of the intestinal net water movement showed that the digestibility and absorption of the disaccharide sugar alcohol, maltitol, in the small gut depended inversely on the dose ingested. For all substances tested, caloric availability in the small intestine was calculated. At a physiological low level of maltitol intake, the results also indicated an insignificant calorie-saving effect in comparison to sucrose, an effect based mainly on the slow absorption rate of the maltitol cleavage product sorbitol.     

Evidence for the induction and release of pancreatic folylpolyglutamate hydrolase by the ingestion of folyl polyglutamates in the rat

Pteroyl polyglutamate hydrolase (folyl conjugase), which hydrolyses the dietary polyglutamyl folates into simple forms prior to absorption, has been shown to be induced in rat pancreas in response to dietary polyglutamyl folates but not by ingestion of synthetic unconjugated folates. Folate absorption, as measured by the rise in serum folate levels after ingestion, of dietary conjugated folates is impaired in pancreatectomised animals whereas absorption of synthetic simple folate is not. A severe build-up of folyl conjugase is observed in the lumen of control but not in pancreatectomised animals after dietary folate ingestion. These results taken together would suggest that dietary folates are hydrolysed to monoglutamyl forms suitable for absorption in the lumen; the hydrolysis is catalysed by a luminal folyl conjugase of pancreatic origin induced by dietary conjugated folates.     

痕量锰的共沉淀分离富集和测定的研究

本研究了用PAN[1-(2-吡啶偶氮)-2-荼酚]共沉淀分离富集人发中的痕量锰．用微量注射进样火焰原子吸收光谱(FAAS)测定的方法。在pH10．5的试样溶液中．不需另加载体．PAN能定量地共沉淀痕量锰。溶液中锰的浓度在0-0．25μg／ml范围内时．标准曲线呈线性。人发中共存的其它元素不干扰测定。锰的标准加入回收率在96-104％之间。12次重复测定锰含量为2．72μg／g的发样的变异系数为4．8％。方法的特征浓度为1．0×10^-3μg／ml.本法简便稳定．用于人发中痕量锰的测定．获得了满意的结果．     

有机共沉淀分离富集原子吸收测定痕量镉

采用APDC(吡咯烷二硫代氨基甲酸铵)-Cu(I)共沉淀体系,在pH3的条件下分离富集酱油消解液中的痕量镉,再用微量注射进样FAAS测定的方法。样品中镉的回收率在92—104％之间。对镉含量为0.59mg/1的样品12次平行测定的变异系数为5.1％。共存物质不干扰测定。溶液中镉的浓度在0—0.125mg/1范围内工作曲线呈线性。方法的灵敏度(标准曲线斜率)为1.079(mg/1)~(-1)。本法快速、简便、稳定。     

New S-25光电阴极红外延伸原因研究

该本研究了S-25与New S-25光电阴极的红外光谱响应特性,分析了New S-25光电阴极红外延伸的原因。研究结果表明:在850～1000 nm范围内New S-25光电阴极红外光谱响应明显提高,主要归因于阴极层较厚,具有较大的阴极结构参量和截止波长。这既是New S-25光电阴极的创新之处,也代表了碱锑光电发射材料的发展方向。     

Benfild溶液吸收、再生系统的数学模型分析及模拟策略

根据Benfild溶液吸收、再生系统循环回路及主要单元设备的特点,提出了合并迭代某些系统断裂变量,直至同时收敛的模拟策略。鉴于描述再生过程的微分方程组的边值问题在某些数域内呈严重病态的情况,采用直接搜索法求解相应的非线性方程组,由此避免了离散牛顿法等一类下降型算法对初值及函数光滑性的要求。系统模拟计算中,因采用上述模拟策略可以避免多次计算描述再生塔的边值问题,故整体计算效率优于联立模块法或序贯模块法。     

全球大气污染与工业防毒技术

通过对全球大气污染进行剖析,指明了酸雨、臭氧空洞与全球变暖是大气污染的三大恶果,并且剖析了我国大气污染日趋严重的现状,系统地介绍了吸收法、吸附法、冷凝法和燃烧法等工业防毒技术的要点及其发展。     

氮酮促进吲哚美辛透皮吸收的研究

本文采用静态简单小室装置以吲哚美辛(Indomethacinum)为模型药物,初步研究了含甲醇水溶液体系中氮酮(Azone)对吲哚美辛的体外透皮吸收的促进作用。实验证明,不同浓度的氮酮液均可促进吲哚美辛的体外透皮吸收,但以其5％的溶液作用最为明显,且有统计学意义。其中含氮酮5％的吲哚美辛液24小时透皮吸收率为76.0％,不含氮酮及含5％二甲基亚砜(DMSO)的吲哚美辛液24小时透皮吸收率分别为23.5％、25.6％。