The effects of phase fractionation on the composition of oils, condensates and gases

The effects of phase fractionation on the composition of oils, condensates and gases have been studied in the laboratory by a differential evaporation experiment. The experiment was designed to simulate the behaviour of a single-charge petroleum during (upward) migration or in a reservoir undergoing uplift, scenarios thought to be typical for the Norwegian continental shelf. After each pressure reduction step, samples from all phases (oil, condensate, free and associated gas) were collected and analysed. The results show that, in general, small molecules are preferentially enriched in the gas phase, both at elevated pressure and temperature and under standard conditions (15°C, 1 bar). The solvent power of the gas phase for large molecules is drastically reduced at lower pressures (here below approx. 300 bar). Carbon isotope ratios of individual compound are not affected, while variations in isotope ratios of fractions can be explained by changes in the fraction compositions. Individual geochemical parameters behave as can be expected based on the molecular size and structure of the compounds involved. However, a generally valid, quantitative prediction of how geochemical parameters vary as a result of phase fractionation is very difficult, as this will depend not only on the pressure and temperature of fractionation, but also on the composition and amounts of the oil and gas that are involved. The observations from this study confirm the importance of phase fractionation as an important process to consider when interpreting geochemical data for both condensates and oils.     

The Analysis of the Seasonal,Spatial, and Compositional Distribution of Humic Substances in a Subtropical Shallow Lake

The spatial and temporal distribution of humic substances in aquatic ecosystems can have important effects on ecosystem productivity, negatively impacting primary productivity while positively impacting secondary productivity. In the present investigation, a large shallow lake ecosystem was studied to determine the spatial and seasonal variation of the composition and concentration of humic substances. Concentrations of total dissolved organic matter, humic acid, and fulvic acid were found to display significant spatial distributions (1.3…13.5 mg/L, DOM; 0.1…5.4 mg/L, HA). The distribution is described by using mapping techniques and the analysis of the spatial distribution of the lake. An analysis of the seasonal variations also indicated the dependence of the occurrence of these compounds on meteorological and hydrological conditions. To identify the potential sources of these organic materials, an analysis was made of the ratio of humic and fulvic acid fractions and total DOM. It was found that areas of high DOM concentration coincided with the areas of highest HA percentage of total DOM. Furthermore using the ratio of the normalised concentrations of HA, FA, and residual DOM (< 5000 g/mol) it was found that areas dominated by each are spatially distinct. This confirms the hypothesis that in these shallow lakes, photodegradation and bacterioplankton activity will create a residence time dependent zonation of each component of the total DOM.     

南极磷虾(Euphausia superba)线粒体基因组特征及其分子标记应用

为揭示南极磷虾（Eupahusia superba）（甲壳动物：软甲纲：磷虾目）线粒体基因组特征,及通过比较不同海域南极磷虾的线粒体基因组探讨潜在的分子标记,采用Long PCR扩增技术获得采自普里兹湾（PrydzBay）南极磷虾线粒体基因组DNA,综合Primers-walking和Shotgun方法进行测序：通过生物信息学软件（DOGMA、tRNAscan-SE 1．21和DnaSP4．10．7等）进行基因预测及序列分析。南极磷虾线粒体基因组全长15498bp以上（部分非编码区未测定）,包含13个蛋白编码基因、2个核糖体RNA基因和23个转运RNA基因。与后生动物线粒体基因组标准的基因组成相比,存在1个trnN基因的重复。南极磷虾线粒体基因组的基因排列与泛甲壳动物线粒体基因组的原始排列相比,出现4个转运RNA基因的易位：trnL1、trnL2、trnW和trnl以及1个trnN的重复。比较采自普里兹湾（Prydz Bay）和威德尔海（Weddell Sea）南极磷虾的线粒体基因组,作者发现在南极磷虾线粒体基因组的主编码基因中,变异最大的是nad2基因,差异位点高达61个,其次是nad5基因,差异位点有12个：而coxl基因的变异位点仅有3个。Nad2基因和nad5基因可作为coxl基因辅助的分子标记,用于分析南极磷虾不同地理种群之间的遗传多样性,为合理利用南极磷虾生物资源提供保障。     

福建九龙江口红树植物分子分类的研究

运用RAPD技术对福建九龙江口龙海红树林自然保护区浮宫种苗园内白骨壤（Auicenmia marina)，桐花树（Ageiceras corniculatum)，无瓣海桑（Sonneratia apatala)，秋茄(Kandeliacandel),木榄（Bruguiera gymnorthiza),海莲（B.sexangula),尖瓣海莲（B.sexangula var,rhynchopetala)等7种红树植物进行了遗传多样性分析，从30个10-mer随机引物中筛选出15个有效引物，利用这15个有效引物共扩增出630条DNA带，其中多态性条带535条，占总扩增条带的84．92％，利用Nei指数法得出7种红树植物间的遗传一致度和遗传距离，并运用UPGA统计分析法对红树植物的7个种间的亲缘关系进行聚类分析，7个种分为A，B两个大组，白骨壤，酮花树，无瓣海垒同属于A组，秋茄，木榄，海莲，尖瓣海莲分聚类在B组，分子聚类结果和传统的分类学相吻合，由此表达这15个有效引物的PAPD分子标记技术能较为客观地反庆出红树植物种间的遗传亲缘关系，并为从分子水平研究红树植物遗传多样性，保护，开发和利用红树林资源提供科学依据。     

Molecular iodine reduction by natural and model organic substances in seawater

The reactivity of 2 µM molecular iodine in seawater toward various organic compounds containing aromatic, -keto, amino, olefinic and sugar functional groups was investigated. More detailed studies have been made of the reduction kinetics with salicylic acid, -ketoglutaric acid and the polypeptide oxidized glutathione, particularly to establish whether variation over the pH range 4–9 would provide a similar reduction reactivity or fingerprint to that of molecular iodine added to natural seawater. The data indicates that compounds with only one functional group react with first order kinetics whereas compounds with multiple functional groups show more complex behaviour. Kinetic and thermodynamic modelling indicates that HOI is the main iodine species reacting with organic matter at seawater pH of 8.2. Based on the pH fingerprints, peptides and compounds containing carbonyl or -keto groups are the key reductants of molecular iodine added to seawater. These compounds form C-I and N-I bonds which can allow for a rich organic iodine chemistry in seawater. The model compound results are discussed in relation to oceanic processes.     

应用烃类流体包裹体GOI和成分研究凝析气藏成藏过程：以准噶尔盆地莫索湾地区为例

The Grains containing Oil Inclusions （GOI） data in currently gas/condensate-beating Jurassic and Cretaceous reservoir sandstones of Well Pen 5 （the Mosuowan area of central Junggar Basin, NW China） are generally greater than the empirical threshold line of 5%. This is consistent with the gas-condensate section originally containing a palaeo-oil column. In order to assess the origin of the oil trapped in the oil inclusion and its relationship to the free oil/gas-condensate, a detailed molecular geochemical study was carried out for correlation between the free and inclusion oils. The paleo oil is most likely sourced from the Lower Permian Fengcheng Formation, which generated hydrocarbons primarily during Late Triassic and the oils were later secondarily altered and dysmigrated along faults likely during Late Jurassic-Early Cretaceous. In contrast, the current reservoired oil/gas-condensate mainly derived from the Middle Permian Lower Wuerhe Formation, whose peak generation time last from Late Cretaceous even to the present. This paper showed that integrated oil-bearing fluid inclusion analyses have likely allowed a complex multi-phase charge history to be recognized and resolved with a high degree of confidence.     

鲫鱼(Carassius auratus)slc7A8基因分子特征及表达分析

采用RT-PCR和RACE技术克隆鲫鱼slc7A8基因的全长cDNA序列,对基因序列用生物软件对基因进行生物信息分析,用Real-time PCR方法检测基因在组织中的mRNA表达丰度。结果表明,鲫鱼slc7A8cDNA全长为2709bp,包含195bp的5′UCR序列,921bp的3′UCR序列,1593bp开放阅读框,编码530个氨基酸序列;鲫鱼与斑马鱼基因同源性和编码氨基酸同源性分别为88.9%和95.5%,而与其他动物分别在70.1%-74.8%和80.6%-82.1%之间;预测编码蛋白的分子量为57719.84,等电点为4.8,对其结构预测显示该蛋白具有与哺乳动物十分相似的12个螺旋跨膜结构,跨膜区氨基酸高度保守,不同动物间的同源性都在92.2%以上;Real-time PCR检测鲫鱼组织中的mRNA表达丰度高低顺序为前肠、中肠、脑、后肠、肌肉、肾、鳃、心、肝脏。     

Jets and molecular outflows from Herbig-Haro objects

We review status of theoretical development for jets and molecular outflows from young stellar objects. A particular framework for explaining these phenomena is one based on the X-wind theory in an environment of magnetized collapsing molecular cloud cores. The magnetized gravitational collapse follows the standard picture of isolated low-mass star formation, from quasi-static evolution of the parent molecular cloud cores. The outflow phenomena operate throughout the early evolution of young stars as a result of star-disk interaction. We discuss emission mechanisms of jets and formation of molecular outflows in this general framework. The general theoretical framework provides room for self-consistent interpretations for recent observations. Jets and outflows are integral part of earliest evolution of young stellar objects.     

Molecular refraction in the Earth's mantle

The Drude law (molecular refraction) for the temperature radiation in a monoatomic model of the Earth's mantle is derived. The considerations are based on the Lorentz electron theory of solids. The characteristic frequency (or eigenfrequency) of independent electron oscillators (in energy units, ) is identified with the band gapE _G of a solid. The only assumption is that solid material related to the Earth's mantle has the mean atomic weight A21 g/mole, and its energy gap (E _G) is about 9 eV. In this case the value of molecular refraction (in cm³/g) is (n ²–1)/=0.5160.52, where andn are the density and the refractive index at wavelength _D=0.5893 m (sodium light), respectively. The average molecular refraction of important silicate and oxide minerals with A21, obtained byAnderson andSchreiber (1965) from laboratory data, is , where denotes the mean arithmetic value calculated from three principal refractive indices of crystal. For the rock-forming minerals with 19A<24 g/mole the new relation was found byAnderson (1975).     

20世纪古生物学的重大进展及21世纪战略重点

20世纪人类积累了大量的生物学、分类学和生物地层数据，这些数据的积累使用进化论和门德尔遗传学结合起来，如遗传学和物种起源、分类学和物种起源、演化的速率和模式、分支系统学等的运用使得古生物学在研究方法上有了新的进展。并提出了21世纪古生物学的战略重点。