烧结砖生产中氟的逸出及钙基废渣固氟特性研究

砖坯烧制过程中，氟逸出的初始温度约为600℃，大部分氟在约800℃至砖坯发生明显烧结的温度内逸出，以CaO含量高的粘土原料制砖，氟逸出量相对较少。在此基础上，提出在制砖原料中添加适量钙基废渣抑制氟的逸出，并进行了详细的实验室和工业性试验；结果表明，在适宜添加量下，存氟率由约25％增至70％以下，且不影响砖制品质量。     

Native fluorescence of unstained cryo-sections of the cervix uteri compared with histological observations

The excellent technical assistance of H. Führer and I. Leib is appreciated. Part of the work was supported by the Bundesministerium für Forschung und Technologie, the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, and from the Leitz and Hoechst companies. This paper is part of the M. D. thesis of Ch.L.     

Predator odour and its impact on male fertility and reproduction in Phodopus campbelli hamsters

 This study investigated the influence of cat urine odour in suppressing development and fertility in Campbell's hamster males. Exposure to this odour from postnatal day 11 until day 45 (sexual maturation) resulted in reduced sex organ weights, reduced testosterone levels and in an increase in abnormalities of the synaptonemal complex in both sex chromosomes and autosomes. Subsequent breeding experiments revealed a significant decrease in litter size. All these data indicate a severe effect of predator odour on the breeding success of potential prey species. It is assumed that these effects are caused by the sulphurous compounds in the urine; however, the underlying mechanisms are not yet known. Received: 31 January 2000 / Accepted in revised form: 6 June 2000     

The Oklo phenomenon

Until recently, scientists believed that the chemical elements were synthesized only in stars. The discovery of the Oklo phenomenon in the Republic of Gabon in 1972 has revealed, however, that a nuclear “fire” had existed on the earth and largescale transmutations of the elements were occurring on our planet 1.7·10⁹ years ago. The formation of natural (or Pre-Fermi) reactors is closely related to the appearance of life on our planet earth. The Pre-Fermi reactors were probably never formed until about 2·10⁹ years ago, when oxygen was injected into the earth's atmosphere by a new generation of living organisms carrying out photosynthesis.