On the origin of fiber calcite crystals in moonmilk deposits

In this study, we show that moonmilk subaerial speleothems in Altamira Cave (Spain) consist of a network of fiber calcite crystals and active microbial structures. In Altamira moonmilks, the study of the typology and distribution of fiber crystals, extracellular polymeric substances, and microorganisms allowed us to define the initial stages of fiber crystal formation in recent samples as well as the variations in the microstructural arrangement in more evolved stages. Thus, we have been able to show the existence of a relationship among the different types of fiber crystals and their origins. This allowed us to outline a model that illustrates the different stages of formation of the moonmilk, developed on different substrata, concluding that microbes influence physicochemical precipitation, resulting in a variety of fiber crystal morphologies and sizes.     

专家畅谈地产节能

一、专家话题 　　话题一：住宅面积强调节约 　　董卫说,从中国现在的发展速度来看,2020年城市人口将达到全国人口的60%,而到国家发展的第三个战略步署即达到中等发达国家水平时,城市人口将占全国的75%以上.但是,与人口城市化的速度和人口增长的速度相比较,国内的人均资源占有将呈现逐步下降的趋势,所以,人均住宅面积一定要节约,要从中国的国情科学地定出一个合理的人均住宅面积.     

Squeezing light out of crystals: Triboluminescence

Triboluminescence is the light emitted when mechanical energy is applied to a crystal. Many common substances such as sugar and copper sulfate are triboluminescent. The origin of the light and the mechanical, chemical, and crystallographic requirements of the phenomenon are described in this paper.     

辽东湾海冰晶体结构及其内部叶绿素的初步研究

本文介绍了１９９６年冬季首次辽东湾生态环境调查中的海洋背景条件。扼要地阐述了辽东湾海冰一般概况，分析辽东湾冰样晶体结构、存储条件及其与冰内和冰下海水叶绿素之间的关系。辽东湾冰内叶绿素符合其它结冰海区的一般规律。根据辽东湾冰层底部实测盐度变化规律阐明海冰对冰下海水营养盐的贡献。最后对深入开展结冰海区生态环境调查工作的技术、侧重点和意义做了讨论。