High concentration retene and methylretene in Silurian carbonate of Michigan Basin

Retene and methylretene have been identified by gas chromatography-mass spectrometry in aromatic hydrocarbon fractions of Silurian carbonate extracts of the Michigan Basin. Retene identified in pre-Devonian carbonates indicates that the compound not only is the biomarker of higher plants but also derived from alga or bacterium. The geochemical significance of methylretene has been discussed.     

Synthesis of self-assembled needle-shaped calcium carbonate superstructures

Novel self-assembled calcium carbonate (CaCO₃) crystals exhibiting the morphology of well-defined needles were synthesized by a simple precipitation reaction in the presence of octadecyl dihydrogen phosphate (ODP) as a crystal additive. The CaCO₃ obtained by this method is hydrophobic, making it likely to be used widely in industry. The resulting products were characterized by powder X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and contact angle experiments. The results indicated that ODP plays an important role in determining the structure, morphology and hydrophobicity of CaCO₃ crystals.     

醇水体系中胰蛋白酶调控下碳酸钙的仿生合成

依据仿生矿化的基本原理,在醇水体系中以胰蛋白酶作为有机基质,CaCl2为钙源,NH4HCO3为CO2来源,采用气体扩散的方法合成了球形的碳酸钙.用XRD,SEM,FT-IR和PL等手段对所得碳酸钙进行了表征,结果发现该球形CaCO3晶体为方解石与球霞石的混合晶型,并发现在CaCO3结晶的过程中,胰蛋白酶和醇水的混合溶剂...     

淡水养殖的珍珠贝壳热分解行为研究

采用FTIR实时红外检测方法研究室温～600 ℃范围内贝壳珍珠层的红外光谱特征,结合热重分析考察淡水养殖珍珠贝壳中的有机和无机组分变化情况.采用扫描电子显微镜观察珍珠层的微结构,并利用X-射线衍射方法测量不同温度下贝壳中无机成分的晶相变化.结果表明,贝壳中氨基酸类有机物热分解后部分以胺的形式挥发,另一部分则转化为不可挥...     

在制备环已酮中Cr~(3 )的回收利用

利用合成正溴丁烷的实验中所回收的Ｎａ２ＣＯ３废液来回收制备环已酮所产生的废液中的Ｃｒ３＋。     

The annexins: spatial and temporal coordination of signaling events during cellular stress

Annexins are a family of structurally related, Ca²⁺-sensitive proteins that bind to negatively charged phospholipids and establish specific interactions with other lipids and lipid microdomains. They are present in all eukaryotic cells and share a common folding motif, the “annexin core”, which incorporates Ca²⁺- and membrane-binding sites. Annexins participate in a variety of intracellular processes, ranging from the regulation of membrane dynamics to cell migration, proliferation, and apoptosis. Here we focus on the role of annexins in cellular signaling during stress. A chronic stress response triggers the activation of different intracellular pathways, resulting in profound changes in Ca²⁺ and pH homeostasis and the production of lipid second messengers. We review the latest data on how these changes are sensed by the annexins, which have the ability to simultaneously interact with specific lipid and protein moieties at the plasma membrane, contributing to stress adaptation via regulation of various signaling pathways.     

青海农区钙层土氮矿化势和供氮速率常数估测

利用一级动力学方程对青海农区栗钙土、灰钙土的氮矿化势和矿化速率常数进行测定，结果表明栗钙土比灰钙土有更高的供氮容量，而供氮强度与环境水分条件有较明确的关系。     

氯化钙型锌锰干电池的研制

研制了一种新型电解液，其成分以氯化钙为主，制成的成品电池放电性能优良，具有耐低温，防温液，贮存期长等优点。     

中国西南部第四纪碳酸钙年代与古环境的地球化学特征

喀斯特地区的泉水和溪流水中沉淀下来的一种次生沉积物，是由碳酸钙过饱和沉淀产生的．碳酸钙沉积或沉积多寡受到多种因素的控制和影响，其中古环境，特别是古气候，影响尤甚．我们通过同位素测年工作，探讨了云贵高原第四纪以来的古环境的演递及其发育历史．