硫铝酸盐“S”型瞬凝水泥

研究了一种在９５０℃左右缎炼温度下烧成的硫铝酸盐“Ｓ”型瞬凝水泥方法，该水泥具有速凝、早期强度高、微膨胀等优点；此外，这种硫铝酸盐“Ｓ”型瞬凝水泥在应用中，具有堵漏成功率高、用量少、成本低和候凝时间短等优点。     

有机-矿质复合材料控释尿素在水稻上的应用效果

试验采用15N示踪的方法,在盆栽水稻上测试了3种新研制的控释尿素(控1、控2、控3)的应用效果。施用3种控释尿素的处理与施普通尿素相比,水稻的氮肥利用率分别增加了3 64、19 92和10 53个百分点,产量分别增加了34 59、18 56和8 66个百分点,控2处理的效果最好。图3,表2,参6。     

Vasoactive intestinal polypeptide stimulates prolactin release in vivo in the ring dove (Streptopelia risoria)

Summary I.v. administration of vasoactive intestinal polypeptide (VIP) to ring doves significantly elevated the plasma concentration of prolactin after 10 min in a dose-related manner. The plasma prolactin concentration of nonbreeding doves with low basal levels was increased by a similar amount as in brooding doves whose initially high concentration of plasma prolactin had been reduced by nest deprivation prior to treatment.     

Impaired insulin release in aging rats: Metabolic and ionic events

We investigated the effect of aging on glucose uptake, glucose-induced O₂ consumption, glucose-induced⁴⁵Ca movements, and calmodulin content to elucidate age-related impairment of glucose-induced insulin release in pancreatic islets of Wistar rats. Intact pancreatic islets from old (24-month-old) rats showed impaired glucose-induced insulin release; glucose uptake and O₂ consumption were lower in old than in young (2-month-old) or adult (12-month-old) rats. Moreover,⁴⁵Ca uptake and calmodulin content were decreased in pancreatic islets from older rats, which explained the impairment in glucose-induced insulin release in aging. No major differences between the 3 age groups in glucose-induced⁴⁵Ca efflux in pancreatic islets were observed.     

Tetanus toxin does not affect the release of noradrenaline and taurine from rat cerebral cortex slices evoked by high K+ and Na+-free media

Summary Noradrenaline and taurine release from superfused rat cerebral cortex slices was stimulated by potassium ions, veratrine, ouabain and omission of sodium ions. Tetanus toxin enhanced only the ouabain-evoked calcium-dependent noradrenaline release and the ouabain-evoked calcium-independent taurine release. The uptake of both was marginally affected.     

The dental amalgam issue. A review

Summary Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included.New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included.It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology.     

基于Willis定理的瞬心线附加板共轭曲线设计的新思路

首先基于Willis定理提出了不完全齿轮机构的瞬心线附加板设计的一种新思路:使待设计的一对瞬心线附加板K、L开始接触后,其接触点的公法线与两轮中心线的交点由主动轮中心开始逐渐按传动比规律移到两轮的节点.但并不要求P点始终在o1o2上;接着运用微分几何原理给出了该对瞬心线附加板共轭轮廓线的求解方法步骤.     

小型低温强制循环热水采暖系统中的安全设施

本文阐述小型低温强剖循环热水采暖系统中预防炉水汽化、循环水的热膨胀、水击以及排污、放气等安全装置的原理、结构和操作方法。     

损伤与断裂耦合效应的能量理论研究及应用

以Ⅰ型裂纹为主要研究对象,基于能量法和损伤能量释放率的概念,推导出一种用于描述裂纹尖端邻域内损伤场与断裂场的耦合效应参数:损伤型能量释放率.运用双G模型理论,应用ANSYS仿真分析三点弯曲梁的裂纹扩展过程,把得到的损伤型能量释放率结果与损伤断裂的参数进行对比分析.结合盖下拱坝工程有限元模型,将人工底缝前沿损伤型的能量释放率、平均损伤、能量释放率以及损伤能量释放率4者随水位变化的发展进行比较,说明该参数可以综合考虑损伤与断裂的耦合效应.此外,建立了该参数的应用模式.