氟污染现状及其治理技术研究进展

主要介绍了地表水中氟污染的现状以及氟污染的危害,分析了氟污染对生态环境、植物、动物及人类的影响,综述了地表水中氟污染的治理方法、研究进展以及除氟机理,并对以后氟污染的治理进行了展望。     

冷酸解离氟电极法测定牙膏中的氟含量

探讨了冷酸解离氟电极法测定牙膏中氟的含量,在冷硝酸介质中牙膏中氟解离效果最佳。讨论了总离子强度调节缓冲剂TISAB的组成及用量、溶液的PH值、加氟标液用量对准确度的影响等。实验结果表明：TISAB（I）用量在20%,溶液PH值在5.0～7.0范围时,氟离子浓度在10-2-10-6mol/L范围内,具有良好的线形关系。回归方程：E=-50.9PF-57.6,相关系数R=0.9995。加入0.50 ml0.01mol/L的氟标液加标回收率为104.1%。     

红枫湖氟化物的变化规律

近年来,由于红枫湖污水处理能力严重不足,城市生活污水直接排入湖中;湖周围部分排污企业始终达不到达标排放,致使红枫湖污染持续加剧,其中氟化物超标是红枫湖受生产性污染的表现现象之一。本文根据近几年来西郊水厂红枫湖进水口氟化物的监测数据,浅探红枫湖氟化物的变化规律,以期说明水资源环境保护的重要性,必要性及所需的预见性。     

环境水中微量氟的测定

介绍了近几年环境水中微量氟测定方法的新进展,包括离子选择电极法、离子色谱法、气相色谱法、高效液相色谱法、原子吸收光谱法、原子发射光谱法、荧光法等,并对其方法进行了评价和展望．     

QCM对牙釉基质蛋白在牙釉质表面的吸附行为

目的:通过石英晶体微天平技术在牙釉质表面吸附牙釉基质蛋白,进而研究牙釉质表面对不同质量浓度蛋白吸附性能的影响。方法:在石英晶片上制备牙釉质膜,将其分别浸入10、20、40μg/mL质量浓度的牙釉基质蛋白溶液;通过共振频率、耗散因子、吸附量随质量浓度的变化关系,得出牙釉基质蛋白吸附的规律。结果:共振频率随质量浓度的提高而降低;吸附量随质量浓度的提高稳定的增长;结论:在20μg/mL的蛋白溶液中,牙釉质表面吸附蛋白的成膜刚性较好。石英晶体微天平技术对牙釉基质蛋白吸附机理的研究显得更直观,是研究蛋白吸附行为的有效工具。     

茶叶中氟的研究进展

综述了茶树含氟特性、生长环境对茶树含氟量影响、茶叶氟的浸出与检测、氟对人体健康的影响及茶叶降氟措施等方面的研究现状.     

氟离子选择性电极的再生利用

提出了一种利用ＮａＯＨ深液再生旧氟离子选择电极的方法。适宜的ＮａＯＨ浓度为０．００１－０．０５ｍｏｌ／Ｌ，浸泡时间为３０－４０ｍｉｎ。     

Significance of enamel thickness in hominoid evolution

Enamel thickness has assumed unique importance in the debate about the hominid status of Ramapithecus, despite the fact that there is little agreement about the meaning of 'thick enamel' or the significance of enamel thickness for hominoid taxonomy. My aim here is to evaluate the usefulness of enamel thickness and microstructure as characteristics for determining the relationships of the later Miocene hominoids, based both on a quantitative study of enamel thickness in extant hominoids and four species of later Miocene Sivapithecus (including 'Ramapithecus') and on scanning electron microscope analysis of enamel microstructure. Four categories of enamel thickness are defined metrically here and have been related to enamel microstructure and developmental rates. Thin fast-formed (pattern 3) enamel represents the ancestral condition in hominoids; it increased developmentally to thick pattern 3 enamel in the great ape and human clade and that condition is primitively retained in Homo and in the fossil hominoid Sivapithecus (including 'Ramapithecus'). Enamel thickness has been secondarily reduced in the African apes and also, although at a different rate and extent, in the orang-utan. Thick enamel, previously the most important characteristic in arguments about the earliest hominid, does not therefore identify a hominid.     

Fast and slow myosin in developing muscle fibres.

Slow and fast isoenzymes of myosin coexist in all the fibres of a fast-twitch mammalian muscle during early development. They later become segregated into different populations of fibres. Slow myosin is most abundant when the speed of contraction of the muscle is slow and the fibres are multiply innervated; its synthesis in the majority of the fibres seems to be 'switched off' when the speed of contraction increases and the fibres become innervated by single motoneurones.     

离子选择性电极法测定牙膏中微量的氟

测定牙膏中氟离子的含量,使用氟离子选择性电极.通过加入TISAB缓冲溶液控制测定条件,利用电位分析法,完成对牙膏中氟离子的测定.结果:回收率为98.91％,检出限为1.0×10-1-1.0×10-6mol/L.说明操作简便,方法可靠,准确度高,检出限低.值得推广.     

去除水体中F-和SO2-4的吸附材料

选择火山渣、 骨炭、 粉煤灰和锰砂为吸附材料, 考察其去除水体中F^-和SO^2-₄的性能, 并将火山渣和骨炭进行改性, 研究其改性后的动力学规律. 结果表明： 火山渣和骨炭对F-的吸附量分别为0.092,0.041 mg/g, 对SO^2-₄的吸附量分别为5.72,3.99 mg/g; 粉煤灰和锰砂对F^-的吸附量均低于0.020 mg/g, 均未吸附SO^2-₄;Al₂(SO₄)₃可作为改性剂; 经质量分数为10%的Al₂(SO₄)₃联合热改性后火山渣对F^-的最大吸附量为0.099 mg/g; 经质量分数为10%的Al₂(SO₄)₃化学改性后火山渣对SO^2-₄的最大吸附量为5.93 mg/g; 二者动力学吸附规律均符合准二级方程.     

超临界二氧化碳中聚氟乙烯的制备

以超临界二氧化碳为介质进行氟乙烯单体的聚合.结果表明在超临界二氧化碳中氟乙烯单体的聚合反应更平稳,所得聚合物规整度更高.