比塔派克斯的根尖诱导效果

目的　探讨比塔派克斯在根尖诱导术中的诱导效果 .方法　选择根尖尚未形成的年轻恒牙牙髓炎或根尖周炎共 112个患牙 (患者 97例 ) .随机分为两组 ,实验组 6 4个牙用比塔派克斯糊剂诱导根尖成形 ,对照组 4 8个牙用氢氧化钙糊剂诱导根尖成形 .结果　实验组根尖诱导效果优于对照组 ,两组间有显著性差异 (P <0 .0 5 ) .结论　比塔派克斯糊剂比氢氧化钙糊剂具有更好的根尖诱导作用     

我国海水制盐业废渣处理利用现状

介绍了盐石膏的理化性质,综述了我国海盐工业废渣盐石膏在水泥、石膏建材等建筑领域以及对盐石膏的深加工等方面的综合利用研究现状,并指出利用盐石膏制备硫酸钙晶须具有广阔的发展前景。     

应用全谱直读光谱仪测定原油中铁和钙元素的含量

提出了利用电感耦合等离子发射光谱ICP -AES法测定原油中铁、钙元素含量的方法 ,考察了雾化压力、RF功率等对被测元素分析线强度的影响 ,确定了仪器的最佳使用条件。试验表明 ,该方法简便、快速、精密度和准确度均令人满意 ,能满足实际应用的要求     

Calcium release from frog sarcoplasmic reticulum by an imidazolyl reagent

Summary Calcium is released from the isolated heavy sarcoplasmic reticulum (SR) of frog skeletal muscle upon application of 0.1–1 mM diethylpyrocarbonate (DEP, an imidazolyl reagent). The Ca-ATPase activity of SR was suppressed by 20% in the presence of 1 mM DEP. More than 1 mM of free magnesium ion or 5 M ruthenium red eliminated the effect of DEP on calcium release but not on Ca-ATPase activity. A plausible site of DEP action is on the calcium channel.     

Effect of feeding cereal-legume diets to rats on in vitro absorption of45Ca

Summary The in vitro absorption of calcium from the duodenum was significantly less in a group of rats fed on a wheat diet than in a group fed a wheat and Bengal gram (7030) diet.     

Effect of calcium ions on the secondary structures of photosystemⅡ and its relations with photoinhibition

Calcium ions play an important role in the oxygen_evolving process of photosystem Ⅱ as demonstrated in many experiments. The changes of the secondary structures of PS Ⅱ induced by the depletion of Ca 2+ were reported. The results indicated that the removal of Ca 2+ led to the transition of α helix to turns and sheet structures. While Ca 2+ was re_added to the media, only the structures changed to turns could be recovered. The protein conformational changes of PS Ⅱ during the donor side photoinhibition induced by the depletion of Ca 2+ were also studied. This showed that the protein conformational changes differed between the control and Ca 2+ _depleted samples in a short period of illumination (within 10 min). However, the changes became similar when the illumination time was increased.     

超重力场中微细晶须碳酸钙结晶过程及产品稳定性研究

在旋转填充床转子高速旋转产生的超重力场中，以MgCl12或H3PO4为晶形控制剂合成微细晶须碳酸钙，通过反应过程中pH值的变化以及针状晶种存在与否两种情形下晶体形貌的演变对结晶过程进行了研究，同时对产品粒子的稳定性进行了初步探讨．结果表明，无晶种存在时，微细晶须碳酸钙晶形的形成需要经历不规则外形-类纺锤形-晶须状-微细晶须状4个阶段；有晶种存在时，产品粒子倾向于在其表面或周围成核，最终所有粒子短轴与长径比趋向均匀；微细晶须碳酸钙粒子在陈化及干燥情形下表现出良好的稳定性．     

聚乙烯胺在CaCO3加填造纸中的作用效果

探讨了在弱碱性条件下聚乙烯胺(PVAm)对CaCO3加填的芦苇浆和废纸浆的助留助滤效果．实验结果表明：PVAm在两种浆中都有非常显著的助滤．助留效果，且在芦苇浆中的助滤效果大于废纸浆．PVAm在芦苇浆中对纤维的助留效果不如废纸浆，但对CaCO3的助留效果高于废纸浆．     

浅谈增钙粉煤灰在抹灰工程中的应用

本文结合工程实际,讨论了用粉煤灰作抹灰砂浆的掺合料在建筑工程中的应用情况,分析了它的应用条件、优点、使田中应予注意的一系列有关问题及其发展前景。     

卤化物与水玻璃复合物的抑尘性能

在恒温箱中测定了粉尘试样添加ＣａＣｌ２或ＭｇＣｌ２和水玻璃后的含水率与环境温度、湿度、有效抑尘时间等因素之间的关系．研究结果表明：（１）当环境温度低于３１℃，相对湿度高于６０％，粉尘试样中ＣａＣｌ２和水玻璃含量的质量分数分别达到２０％和１０％（ＭｇＣｌ２和水玻璃含量的质量分数为２３％和１１．５％）时，试样的含水率就能保持大于５％（质量分数）；（２）当环境温度低于４０℃，相对湿度高于５０％，粉尘试样中ＣａＣｌ２和水玻璃含量的质量分数分别达到２６％和１３％（ＭｇＣｌ２和水玻璃含量的质量分数为３０％和１５％）时，试样的含水率就能保持大于５％（质量分数）；（３）ＣａＣｌ２或ＭｇＣｌ２与水玻璃复合后，其粘尘功能进一步增强，而且其溶液的弱酸性得到进一步降低。