Identification of the interstellar cyanomethyl radical (CH2CN) in the molecular clouds TMC-1 and Sagittarius B2     

Irvine WM  Friberg P  Hjalmarson A  Ishikawa S  Kaifu N  Kawaguchi K  Madden SC  Matthews HE  Ohishi M  Saito S  Suzuki H  Thaddeus P  Turner BE  Yamamoto S  Ziurys LM 《The Astrophysical journal》1988,334(2):L107-L111

We report the astronomical identification of the cyanomethyl radical, CH2CN, the heaviest nonlinear molecular radical to be identified in interstellar clouds. The complex fine and hyperfine structures of the lowest rotational transitions at about 20.12 and 40.24 GHz are resolved in TMC-1, where the abundance appears to be about 5 x 10(-9) relative to that of H2. This is significantly greater than the observed abundance of CH3CN (methyl cyanide) in TMC-1. In Sgr B2 the hyperfine structure is blended in the higher frequency transitions at 40, 80, and 100 GHz, although the spin-rotation doubling is clearly evident. Preliminary searches in other sources indicate that the distribution of CH2CN is similar to that for such carbon chain species as HC3N or C4H.  相似文献   

Variations in the HCN/HNC abundance ratio in the Orion molecular cloud     

Goldsmith PF  Irvine WM  Hjalmarson A  Elldér J 《The Astrophysical journal》1986,310(1):383-391

We have used observations of the rare isotopes of HCN and HNC to determine the relative abundance of these two chemical isomers along the central ridge of the Orion molecular cloud. The abundance ratio [HCN]/[HNC] decreases by more than an order of magnitude from the relatively warm plateau and hot core sources toward the KL nebula to the colder, more quiescent clouds to the north and south. Even in the cooler regions, however, the ratio is an order of magnitude larger than that found in previous investigations of cold dark clouds. We determine the kinetic temperature in the regions we have studied from new observations of methylacetylene (CH3CCH), together with other recent estimates of the gas temperature near KL. The results suggest that the warmer portions of the cloud are dominated by different chemical pathways than those in the general interstellar cloud material.  相似文献   

Stable isotope study of the Archaean rocks of the Vredefort impact structure,central Kaapvaal Craton,South Africa     

Åke Fagereng  Chris Harris  Mandy La Grange  Gary Stevens 《Contributions to Mineralogy and Petrology》2008,155(1):63-78

The Vredefort dome in the Kaapvaal Craton was formed as a result of the impact of a large meteorite at 2.02 Ga. The central core of Archaean granitic basement rocks is surrounded by a collar of uplifted and overturned strata of the Witwatersrand Supergroup, exposing a substantial depth section of the Archaean crust. Orthogneisses of the core show little variation in whole-rock δ ¹⁸O value, with the majority being between 8 and 10‰, with a mean of 9.2‰ (n = 35). Quartz and feldspar have per mil differences that are consistent with O-isotope equilibrium at high temperatures, suggesting minimal interaction with fluids during subsequent cooling. These data refute previous suggestions that the Outer Granite Gneiss (OGG) and Inlandsee Leucogranofels (ILG) of the core represent middle and lower crust, respectively. Granulite-facies greenstone remnants from the ILG have δ ¹⁸O values that are on average 1.5‰ higher than the ILG host rocks and are unlikely, therefore, to represent the residuum from the partial melting event that formed the host rock. Witwatersrand Supergroup sedimentary rocks of the collar, which were metamorphosed at greenschist-to amphibolite-facies conditions, generally have lower δ ¹⁸O values than the core rocks with a mean value for metapelites of 7.7‰ (n = 45). Overall, through an ∼20 km thick section of crust, there is a general increase in whole-rock δ ¹⁸O value with increasing depth. This is the reverse of what is normal in the crust, largely because the collar rocks have δ ¹⁸O values that are unusually low in comparison with metamorphosed sedimentary rocks worldwide. The collar rocks have δD values ranging from −35 to −115‰ (average −62‰, n = 29), which are consistent with interaction with water of meteoric origin, having a δD of about −25 to −45‰. We suggest that fluid movement through the collar rocks was enhanced by impact-induced secondary permeability in the dome structure. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

Partial isolation and purification of cadmium-binding proteins from rainbow trout liver     

Carl Haux  Per Erik Olsson  Inger Thorsen  Lars Frlin  ke Larsson 《Marine environmental research》1984,14(1-4)

  相似文献   

Acid leaching of ash and coal: Time dependence and trace element occurrences     

Mehtap Paul  Meryem Seferinoğlu  Gul Asiye Ayçık  Åke Sandström  Michael L. Smith  Jan Paul 《International Journal of Mineral Processing》2006

The leaching of coal and coal/asphaltite/wood-ashes in sulfuric acid (pH 1.0, 25 °C, S/L, 1:10) was studied as a function of time; acid consumption and extracted metal concentrations are presented. Whole coals consumed acid rapidly during the first few minutes, followed by slow acid consumption. Wood-, lignite-, and asphaltite-ashes consumed acid in two stages, the rapid phase extending < 30 min and the slow phase extended up to 10 days. The rapid phase was dominated by the dissolution of Ca, K and Mg ions for wood-ash, by Ca, Al and Mg ions for lignite-ash and Ca and Mg ions for asphaltite-ash. The sulfur concentration in solution and the concentrations of Ca, Fe, K, Mg, Na, P, Al and Mn in the aqueous phase verified the neutralizing capacity of the untreated ashes as well as the formation of insoluble sulfates in the residues. The slow phase kinetics differed for different fuels and exhibited leaching of several abundant elements—Fe, Al, K, Na and Mn. Trace elements (Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Th, U, V, Zn) sometimes required up to 32 h for maximal extraction from ashes. Suggestions are presented regarding the chemical nature of trace elements in the untreated coals and ashes and suitable residence times for economical industrial processes. We think it possible to combine bacteriological oxidation of sulfidic concentrates of acid leaching from ash of various qualities or even whole coals.  相似文献   

泌阳凹陷安棚油田深层系成岩作用研究及其在成岩圈闭预测中的应用   总被引：14，自引：2，他引：14  

金振奎  陈祥  明海慧  周新科  邹元荣  张响响 《沉积学报》2002,20(4):614-620

深层系一般指沉积盆地中埋藏深度在2 500～2 700 m以下的地层,其储集物性普遍很差,但在一定条件下,深部溶蚀作用可产生优质储层,形成成岩圈闭.然而这种成岩圈闭的预测一直是一个难题.安棚油田位于河南泌阳凹陷东南部,勘探成果表明,在该油田深层系下第三系核桃园组核三段下部(简称(核三下)席状的扇三角洲砂体中存在成岩圈闭.本次通过定量的成岩作用研究和成岩阶段划分,对成岩圈闭的形成机理和分布进行了探讨.研究表明,该区核三下的砂体经历了压实、胶结、溶蚀等多种成岩作用,不同的成岩作用发生于不同的埋藏深度.2 700～3 100 m之间以胶结强烈为特征,属于胶结带.3 100～3 900 m之间以次生溶蚀孔隙发育为特征,尤其是3 200～3 600 m之间, 属于深部溶蚀带.本区核三下砂体自南而北埋藏深度逐渐变浅,其上倾方向处于胶结带的部分由于强烈胶结而变成致密层,可封堵油气,而下倾方向处于溶蚀带的部分由于次生溶蚀孔隙发育而成为良好储层,从而形成成岩圈闭.根据不同埋藏深度、不同成岩阶段孔隙发育和保存的特征,可预测成岩圈闭分布。  相似文献   

地幔热柱及其成矿作用研究     

牛树银  孙爱群  谢汝斌  许传诗  王宝德  杨志宏  毕伏科  孙冀凡 《华北地质》2002,25(1):11-22

成矿作用研究表明 ,在地球的演化历史中 ,成矿数量有从少到多 ,聚矿能力有由弱到强的演化趋势。中生代为全球规模的成矿大爆发阶段 ,究其原因可能与地球的发展演化密切相关。地球形成的早期 ,由于地球物质尚未充分分异 ,成矿强度不大。当然 ,有部分在地球演化早期形成的矿床 ,在后来的多次构造改造过程中被改造迁移 ,甚至消失。中生代地球进入了一个强烈的地幔热柱活动时期 ,聚集于D”层及外核的成矿物质可通过地幔热柱多级演化向上迁移 ,并在幔枝构造的有利构造扩容带中成矿 ,幔枝构造则成为中生代主要的成矿控矿构造类型  相似文献   

重油凝胶色谱制备样品中痕量镍的分析研究          下载免费PDF全文

朱玉霞许世科  陆婉珍 《岩矿测试》2003,22(2):129-133

研究表明微波密闭消解法对重油凝肢色谱制各样品的前处理，不造成易挥发有机金属化合物的损失，对样品无污染。采用消解前定容，配合石墨炉二次进样富集样品，可以测定样品中低至10^—9级的镍。方法应用于镍在渣油中随相对分子质量分布分析中，标准样品对照数据吻合好，相对标准偏差(RSD，n＝11)为8％。  相似文献   

软土路基沉降与软土层厚度及填土高度的关系分析   总被引：5，自引：0，他引：5  

王良民  朱长歧  阎钶 《岩土力学》2003,(Z2)

本文就路基沉降观测资料进行深入分析,总结出路基沉降与软土层厚度及填土高度的关系和规律,并分析了原因,推导出计算路基沉降的公式,提出了判断填土速率快慢和填土高度变化大小的新方法。  相似文献   

Free allocation in the 3rd EU ETS period: assessing two manufacturing sectors     

Christian Stenqvist  Max Åhman 《Climate Policy》2016,16(2):125-144

This article provides an analysis of the EU Emissions Trading Scheme (ETS) and the harmonized benchmark-based allocation procedures by comparing two energy-intensive sectors with activities in three Member States. These sectors include the cement industry (CEI) and the pulp and paper industry (PPI) in the UK, Sweden, and France. Our results show that the new procedures are better suited for the more homogeneous CEI, in which the outcome of stricter allocation of emissions allowances is consistent between Member States. For the more heterogeneous PPI – in terms of its product portfolios, technical infrastructures, and fuel mixes – the allocation procedures lead to diverse outcomes. It is the lack of product benchmark curves, and the alternative use of benchmark values that are biased towards a fossil fuel-mix and are based on specific energy use rather than emission intensity, which leads to allocations to the PPI that do not represent the average performance of the top 10% of GHG-efficient installations. Another matter is that grandfathering is still present via the historically based production volumes. How to deal with structural change and provisions regarding capacity reductions and partial cessation is an issue that is highly relevant for the PPI but less so for the CEI.

Policy relevance

After an unprecedented amount of consultation with industrial associations and other stakeholders, a harmonized benchmark-based allocation methodology was introduced in the third trading period of the EU ETS. Establishing a reliable and robust benchmark methodology for free allocation that shields against high direct carbon costs, is perceived as fair and politically acceptable, and still incentivizes firms to take action, is a significant challenge. This article contributes to a deeper understanding of the challenges in effectively applying harmonized rules in industrial sectors that are heterogeneous. This is essential for the debate on structural reformation of the EU ETS, and for sharing experiences with other emerging emissions trading systems in the world that also consider benchmark methodologies.  相似文献