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Wdowiak TJ Lee W Cronin J Beegle LW Robinson MS 《Planetary and Space Science》1995,43(10-11):1175-1182
Processes resulting in the formation of hydrocarbons of carbonaceous chondrites and the identity of the interstellar molecular precursors involved are an objective of investigations into the origin of the solar system and perhaps even life on earth. We have combined the resources and experience of an astronomer and physicists doing laboratory simulations with those of a chemical expert in the analysis of meteoritic hydrocarbons, in a project that investigated the conversion of polycyclic aromatic hydrocarbons (PAHs) formed in stellar atmospheres into alkanes found in meteorites. Plasma hydrogenation has been found in the University of Alabama at Birmingham Astrophysics Laboratory to produce from the precursor PAH naphthalene, a new material having an IR absorption spectrum (Lee, W. and Wdowiak, T.J., Astrophys. J. 417, L49-L51, 1993) remarkably similar to that obtained at Arizona State University of the benzene-methanol extract of the Murchison meteorite (Cronin, J.R. and Pizzarello, S., Geochim. Cosmochim. Acta 54, 2859-2868, 1990). There are astrophysical and meteoritic arguments for PAH species from extra-solar sources being incorporated into the solar nebula, where plasma hydrogenation is highly plausible. Conversion of PAHs into alkanes could also have occurred in the interstellar medium. The synthesis of laboratory analogs of meteoritic hydrocarbons through plasma hydrogenation of PAH species is underway, as is chemical analysis of those analogs. The objective is to clarify this heretofore uninvestigated process and to understand its role during the origin of the solar system as a mechanism of production of hydrocarbon species now found in meteorites. Results have been obtained in the form of time-of-flight spectroscopy and chemical analysis of the lab analog prepared from naphthalene. 相似文献
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准噶尔盆地滴西地区石炭系火山岩识别与预测 总被引：3，自引：1，他引：2
准噶尔盆地腹部滴西地区石炭系火山岩储层中已获重要的工业气流。然而由于成岩环境复杂,岩性多变,火山机构受后期风化剥蚀和构造作用的影响,保存不完整,使得该区火山岩研究难度大,认识程度较低。本文对滴西地区石炭系巴塔玛依内山组火山岩特征进行了研究,分析了该区典型岩性的岩心、岩石薄片及测井响应特征,提出了一套火山岩测井识别的方法。在此基础上,总结了典型岩性组合的地震反射特征,并对岩性的展布情况进行了预测。最后,对火山岩形成的环境进行了探讨。研究结果显示,滴西地区巴塔玛依内山组顶面的火山岩分布具有一定的分段特征,可以分为东部、中部、西部三段: 从成分上看,东部以酸性岩为主,西部以基性岩为主,中部则酸性岩、中性岩和基性岩皆较发育; 从火山岩产状上看,东部和西部以喷出产状为主,中部则侵入产状和喷出产状皆发育。巴塔玛依内山组火山岩体具有多期次的特点,各火山机构彼此叠置,时间和空间上具有一定的相关性。层状火山机构发育。本文的研究方法对准噶尔盆地内石炭系火山岩研究及火山机构的解剖具有借鉴意义,同时也为该区的油气勘探和开发提供一定的依据。 相似文献
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松辽盆地长岭断陷营城组火山岩储集空间特征及演化 总被引：4，自引：0，他引：4
通过对长岭断陷营城组火山岩岩心、铸体薄片的详细观察和物性资料的统计分析认为,该区储层岩石类型多样,主要有流纹岩、流纹质晶屑凝灰岩和原地自碎角砾化熔岩等,不同岩石类型其储集空间发育特征不同,但主要由原生气孔、次生溶孔和裂缝组合构成储集空间。储集空间演化过程可分为三个阶段:原生储集空间形成阶段、表生淋滤作用阶段和埋藏成岩作用阶段,在以上演化过程中,储集性能受岩性岩相、构造运动和风化淋滤溶蚀作用的共同影响,在受深大断裂控制的火山机构近火山口相带、古构造高部位的溶蚀岩相带,裂缝及后期溶蚀孔隙发育,是优质储层分布区。 相似文献
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A mixture of the polycyclic aromatic hydrocarbons (PAHs), acenaphthylene and acenaphthene, when subjected to the energetic environment of a hydrogen plasma, is transformed into a material that exhibits an infrared absorption profile in the 3 micron region that is an excellent match of the protoplanetary nebula IRAS 05341+0852 emission profile in the same wavelength region. Acenaphthylene and acenaphthene were chosen as precursors in the experiment because these molecules have a structure that can be described as a keystone in a process in which carbon atoms in a stellar wind condense into PAH species. The spectral match between experiment and observations appears to validate that scenario. 相似文献
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Freshly excreted droppings from Canada geese (n=80), black swans (n=80), ducks (n=80) and gulls (n=80) were collected from sites around New Zealand. The droppings were enumerated for Escherichia coli, enterococci and Salmonella spp., and for the presence/absence of Cryptosporidium spp. Overall prevalence of E. coli and enterococci in samples was 95% and 94%, respectively. Cryptosporidium spp. was detected in 2% of the samples, whereas no Salmonella spp. were detected in the survey. Preliminary estimates of daily microbial outputs suggest that ducks will produce the highest loadings of E. coli and enterococci per bird, whereas Canada geese will produce the highest loadings of Campylobacter spp. per bird. This study provides the first set of indicator and pathogen counts for one of the largest sources of diffuse faecal contamination of natural waters in New Zealand. 相似文献
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东准噶尔滴西地区石炭系火成岩岩相特征及分布预测 总被引：1，自引：0，他引：1
含油气火成岩储层的研究为石油勘探开拓了更广阔的前景。东准噶尔滴西地区石炭系火成岩气藏是克拉美丽气田的主体部分,位于陆梁隆起东南部的滴南凸起西端。根据钻井取心、薄片观察及成像测井数据,对滴西地区石炭系的火成岩岩性进行了识别和类型划分; 结合测井、地震等资料,在单井相划分的基础上,以井震结合为方法,建立了不同岩相的地震相模式,并对其不同特征进行了分析; 通过建立地质-地震对应关系,运用时间切片、波形分类等地震属性分析技术对研究区岩相分布进行了预测。研究结果表明滴西地区火成岩发育火山通道相、爆发相、溢流相、火山沉积相和侵入相五种岩相; 研究区火山岩岩相分区性明显,整体呈现西北部以中-基性溢流相为主,中部以爆发相和火山沉积相为主、东南部以中-酸性溢流相为主的分布特点,滴西18井区为独立的侵入岩体,为浅成侵入相。 相似文献
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The discrete infrared features known as the unidentified infrared (UIR) bands originating in starburst regions of other galaxies, and in H II regions and planetary nebulae within the Milky Way, are widely thought to be the result of ultraviolet pumped infrared fluorescence of polycyclic aromatic hydrocarbon (PAH) molecules and ions. These UIR emissions are estimated to account for 10%-30% of the total energy emitted by galaxies. Laboratory absorption spectra including the vacuum ultraviolet region, as described in this paper, show a weakening of the intensity of absorption features as the population of cations increases, suggesting that strong pi* <-- pi transitions are absent in the spectra of PAH cations. This implies a lower energy bound for ultraviolet photons that pump infrared emissions from such ions at 7.75 eV, an amount greater than previously thought. The implications include size and structure limitations on the PAH molecules and ions which are apparent constituents of the interstellar medium. Also, this might affect estimations of the population of early-type stars in regions of rapid star formation. 相似文献
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We report on sorting of small grained material under simulated martian conditions in order to better understand the nature of particle movement in the acquisition-to-analysis chain for future martian missions. We find that triboelectric charging when material is sieved is a major phenomenon that has to be understood and mitigation strategies explored in order to be able to successfully move particles under these types of conditions while minimizing cross sample talk. In different experimental set-ups, we have observed such phenomena as caking of the sieve, adhesion of particles to hardware, clodding of dry fines, and electrostatic repulsion. These phenomena occur when different experimental testing is performed with varied configurations and environmental conditions. Identifying these electrostatic effects can help us understand potential bias in the analytical instruments and to define the best operational protocols to collect samples on the surface of Mars. These experiments demonstrate the need for end-to-end system testing under the most realistic environmental conditions and platforms before mission configurations can be demonstrated before launch. 相似文献
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