尖晶石CoAl2O4中阳离子分布的温度依赖性

本通过Ｘ射线粉末衍射数据的Ｒｉｅｔｖｅｌｄ结构精化法，确定了经过７５０－１２００℃淬火的合成尖晶石ＣｏＡｌ２Ｏ４样品的阳离子分布。其反生参数ｘ随温度７５０－１２００℃相应地从０．１１平滑增加到０．２５（±０．００５），并可用带有ａｃｏ－Ａｌ＝４５．３＋０．５，β＝－１８．３±１．２ｋＪ／ｍｏｌ的一般热力学模型描述。     

Nature, distribution and origin of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Olbia harbor (Northern Sardinia, Italy)

The nature, origin and distribution of US EPA polycyclic aromatic hydrocarbons (PAHs) in the sediments of Olbia harbor (North Sardinia, Italy) were investigated by gas-chromatography/mass spectrometry (GCMS). PAH concentrations in the sediments (SigmaPAHs) ranged from 0.16 to 0.77 microg g(-1), indicating a homogeneously low level of pollution. A rather exceptional prevalence of low molecular weight PAHs was substantiated: nearly 80% of SigmaPAHs include naphthalene (15.19%) and phenanthrene (64.47%). Carcinogenic compounds were present in very low (BaP, BkF, BaA and DBA) or negligible (BbF and Inp) concentrations. As indicated by the Phen/Ant molar ratio, the main source of PAHs is petrogenic, probably due to oil spills from shipping. The low/high molecular weight ratio (ranging between 1.2 and 26) distinguishes the sediments of the tourist harbor from those of the commercial/industrial harbor. Moreover, a slight but meaningful pyrolytic contribution to pollution was found in the tourist harbor, which has the most polluted sediments in the whole harbor. Finally, good linear correlations were found between a selected PAH (Phen and Naph) and selected sums of PAHs (i.e. the total amount of the other 15 US EPA and the sum of low molecular weight PAHs).     

北福克兰盆地的地质特征

北福克兰盆地的地质特征Ｐ．Ｃ．Ｒｉｃｈａｒｄｓ等位于福克兰岛北部的北福克兰盆地，水深１５０—２００ｍ，由伴随着两条主要构造线走向（ＮＷ—ＳＥ和Ｓ—Ｎ向）产生的平错沉积中心的复杂体系组成，形成了与福克兰岛其他近海盆地绝然不同的构造风格。其边界通常是断裂...     

Effects of furadan in the brown mussel Perna perna and in the mangrove oyster Crassostrea rhizophorae

Furadan is a carbamate pesticide used widely to combat agricultural pests. However little information is available about the toxicity of furadan in aquatic macroinvertebrates. The in vivo effects of furadan were evaluated in mussels, Perna perna, and oysters, Crassostrea rhizophorae. Glutathione S-transferase (GST), catalase (CAT) and cholinesterase (ChE) activities were measured in the gills of both species exposed to furadan (100 microg/l) for 96 h. No changes were observed in GST activity in the exposed groups. CAT activity was higher (9%) in the oysters exposed to furadan. ChE activity was inhibited by 64 and 35%, respectively, in C. rhizophorae and P. perna exposed to furadan, suggesting that the former is more susceptible to the toxic effects of furadan.     

量子地球化学的研究进展和发展展望

量子地球化学是应用量子力学理论研究地球物质的结构物理与结构化学的一个新理论。综述了量子地球化学理论建立以来,在矿物的结构、地球化学特征,乃至地球科学中的研究方面的最新进展,揭示了矿物中的元素分配与晶体结构等量子地球化学的研究核心,以及矿物的表面和内部电子结构、元素的分配及其动力学机制,显示量子地球化学在地球科学理论和应用领域有极广阔的前景。