Raman spectroscopic measurements of synthetic gas hydrates in the ocean   总被引：1，自引：0，他引：1  

K.C. Hester  S.N. White  E.T. Peltzer  P.G. Brewer  E.D. Sloan   《Marine Chemistry》2006,98(2-4):304-314

A Raman spectrometer extensively modified for deep ocean use was used to measure synthetic hydrates formed in an ocean environment. This was the first time hydrates formed in the ocean have been measured in situ using Raman spectroscopy. Gas hydrates were formed in situ in the Monterey Bay by pressurizing a Pyrex cell with various gas mixtures. Raman spectra were obtained for sI methane hydrate and sII methane + ethane hydrate. Gas occlusion resulting from rapid gas growth of methane hydrate was measured immediately after formation. The Raman shift for methane free gas was coincident with that of methane in the small 5¹² hydrate cage. The methane Raman peak widths were used to discriminate between methane in the free gas and hydrate phase. Methane + ethane sII hydrate was formed for 43 days on the seafloor. In this case, gas occlusion was not measured when the gas hydrates were allowed to form over an extended time period. Equivalent Raman spectra were obtained for the in situ and laboratory-formed sII methane + ethane hydrates, under similar p, T, and x conditions. With the Raman spectrometer operating in the ocean, seawater contributes to the Raman spectra obtained. Both the Raman bands for the sulfate ion and water were used to qualitatively determine the distribution of water phases measured (hydrate, seawater) in the Raman spectra.  相似文献   

Magnetically enhanced coagulation of very small iron grains   总被引：3，自引：0，他引：3  

Nuth JA rd  Berg O  Faris J  Wasilewski P 《Icarus》1994,107(1):155-163

Laboratory experiments, in which very small (approximately 20 nm) grains are produced in the presence of a magnetic field on the order of 100 Gauss in a low-pressure hydrogen atmosphere, have demonstrated that such smokes can become permanently magnetized. We show that magnetization results in an enormous enhancement in the coagulation efficiency of such materials even in the absence of external magnetic fields. Small iron grains should have been produced in the solar nebula by thermal processing of preexisting interstellar grains. If such processing occurred via high-energy electromagnetic events then the resultant magnetized grains could have triggered the formation of centimeter- to meter-sized protoplanetessimals by acting as "nets" capable of sweeping up nonconductive silicates suspended in the gas. It is possible that the presence of conductive fractal aggregates observed in modern-day protostellar disks could be explained by the enhanced coagulation efficiency of very small magnetized iron particles.  相似文献   

Magnesium Isotopic Compositions of International Geological Reference Materials          下载免费PDF全文

Fang‐Zhen Teng  Wang‐Ye Li  Shan Ke  Wei Yang  Sheng‐Ao Liu  Fatemeh Sedaghatpour  Shui‐Jiong Wang  Kang‐Jun Huang  Yan Hu  Ming‐Xing Ling  Yan Xiao  Xiao‐Ming Liu  Xiao‐Wei Li  Hai‐Ou Gu  Corliss K. Sio  Debra A. Wallace  Ben‐Xun Su  Li Zhao  Johnnie Chamberlin  Melissa Harrington  Aaron Brewer 《Geostandards and Geoanalytical Research》2015,39(3):329-339

Magnesium isotopic compositions are reported for twenty‐four international geological reference materials including igneous, metamorphic and sedimentary rocks, as well as phlogopite and serpentine minerals. The long‐term reproducibility of Mg isotopic determination, based on 4‐year analyses of olivine and seawater samples, was ≤ 0.07‰ (2s) for δ²⁶Mg and ≤ 0.05‰ (2s) for δ²⁵Mg. Accuracy was tested by analysis of synthetic reference materials down to the quoted long‐term reproducibility. This comprehensive dataset, plus seawater data produced in the same laboratory, serves as a reference for quality assurance and inter‐laboratory comparison of high‐precision Mg isotopic data.  相似文献   

Potential Orthopyroxene,Clinopyroxene and Olivine Reference Materials for In Situ Lithium Isotope Determination   总被引：1，自引：0，他引：1       下载免费PDF全文

Ben‐Xun Su  Xiao‐Yan Gu  Etienne Deloule  Hong‐Fu Zhang  Qiu‐Li Li  Xian‐Hua Li  Nathalie Vigier  Yan‐Jie Tang  Guo‐Qiang Tang  Yu Liu  Kwan‐Nang Pang  Aaron Brewer  Qian Mao  Yu‐Guang Ma 《Geostandards and Geoanalytical Research》2015,39(3):357-369

Over 1400 electron probe and 700 ion probe microanalyses were performed on eleven mineral separates to evaluate their potential as reference materials for in situ Li isotopic determination. Our results suggest the homogenous distributions of major elements, Li and its isotopes for each sample. Hence, these samples are suitable to be used as reference materials for in situ measurements of Li abundance and Li isotopes by secondary ion mass spectrometry (SIMS) or laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). These samples have the advantage of mitigating probable matrix effects during calibration owing to the wide range of compositions. The effect of composition on the δ⁷Li of olivine measured by SIMS is a linear function of composition, with δ⁷Li increasing by 1.0‰ for each mole per cent decrease in forsterite component.  相似文献   

Book reviews     

Sfephen Brewer  James H. Cowan  J. A. Nyman  Bernard C. Patten  Robert E. Ulanowicz 《Estuaries and Coasts》1999,22(2):337-343

  相似文献   

“Nature and Estimated Human Toxicity of Polar Metabolite Mixtures in Groundwater Quantified as TPHd/DRO at Biodegrading Fuel Release Sites,”     

Roger C. Brewer  Uta Hellmann‐Blumberg 《Ground Water Monitoring & Remediation》2014,34(2):24-25

  相似文献   

气候变暖条件下,中(高)亚洲地区不稳定型冻土的巨大挑战和创新解决方案:——来自首届亚洲冻土大会及会后青藏高原考察的总结报告     

金会军  马巍  赖远明  吴青柏  王贵荣  牛富俊  沈永平  赵淑萍  Jerry Brown  Max C.Brewer 《冰川冻土》2006,28(6):838-843

首届亚洲冻土大会于2006年8月5~16日在兰州、青藏线和拉萨顺利召开.大会讨论主要包括以下5个议题:1)冻土工程;2)山区和高原冻融灾害及冰缘环境;3)冰冻圈的气候与环境条件;4)冻土水文、寒区水资源及土地利用,和;5)冻土监测、制图及模拟.国内论文大多集中于青藏铁路各种科技创新和工程(示范)建设方面.中亚冻土分类、制图和监测研讨会明确了制定统一的中亚地区冻土图的计划和实施方案.会议期间,国内主要新闻媒体对全球15位著名冻土学家进行了联合采访.大约80位中外代表参加了青藏(公)铁路沿线考察,并于8月15日在拉萨举行青藏铁路工程和环境问题讨论会.专家一致认为,青藏铁路所采取的冻土工程措施基本上是恰当、有效的,能够保证青藏铁路路基的长期稳定性.但是,沿线寒区环境保护问题还任重道远,需要尽快进行综合管(治)理,以达到青藏地区社会经济和谐、持续发展的目标.  相似文献   

A natural hydrate dissolution experiment on complex multi-component hydrates on the sea floor     

K.C. Hester  E.T. Peltzer  R.M. Dunk  P.G. Brewer 《Geochimica et cosmochimica acta》2009,73(22):6747-285

Dissolution of natural hydrate cores was measured using time-lapse photography on the seafloor at Barkley Canyon (850 m depth and 4.17 °C). Two types of hydrate fabrics in close contact with one another were studied: a “yellow” hydrate stained with condensate oil and a “white” hydrate. From thermogenic origins, both fabrics contained methane as well as heavier hydrocarbons. These multi-component hydrates were calculated to be well within p-T stability conditions (<200 m water depth needed at 4.17 °C). While stable in pressure and temperature, the hydrates were bathed in under-saturated seawater, which promoted dissolution. The flux of gas from the shrinking yellow hydrate core was 0.15 ± 0.01 mmol gas/m² s, while the white hydrate dissolved faster at 0.25 ± 0.02 mmol gas/m² s. To determine the controlling mechanism for the observed changes in the hydrate cores, experimental results were compared with an engineering correlation for convective mass transfer. Using water velocity as a fitting parameter, the correlation agreed well with results from a previous dissolution experiment on well-characterized synthetic hydrates. Even with a number of other unknowns, when applied to the natural hydrate, the mass transfer correlation predicted the dissolution rate within 20%. This seafloor-based experiment, along with visual observations of seafloor hydrate dissolution over a 3-day period, were used to further understand the fate of natural seafloor hydrates exposed on the seafloor. By showing that mass transfer is the rate-controlling mechanism for dissolution of these natural hydrate outcrops, proper hydrodynamic calculations can be employed to give a refined estimate on hydrate dissolution rates.  相似文献   

阿拉斯加北极地区的工程设计和施工经验及教训   总被引：13，自引：7，他引：6  

金会军  Max C.Brewer 《冰川冻土》2005,27(1):140-146

阿拉斯加北极地区位于布鲁克斯山以北, 白令海峡以东的北坡地区, 属北极海洋性气候区. 区内寒冷( -10 ～ -6 ℃)、连续多年冻土厚度多在200～300 m, 局部达700 m. 地表湖塘和冰楔多边形广泛分布. 阿拉斯加北极地区的工程建筑活动主要为海军部和商业石油勘探、开发和运输服务. 从20世纪40年代以来, 尽管有不少的曲折和教训, 但成功和可以借鉴的经验很多. 最成功的例子当数普如道湾油气田开发、阿里亚斯卡输油管道工程及其相应的环境保护措施. 工程师为了成功和经济地在北极地区修筑和运行工程设施, 必须从"冷"处着想, 并付诸计划和行动. 设计和施工的工程师必须保持实事求是、不断创新精神, 而不拘泥于中纬度地区的教育、培训, 或行业传统. 从工程勘察、设计到施工阶段, 工程师和从事环境研究的科学家必须密切合作. 工程师需要知道环境参数, 制约因素和可利用的机会; 环境科学家需要知道工程师的施工设计和问题, 理解工程限制条件、设备工作能力, 以及备选方案的经济学问题. 这些相互理解只能在密切合作中形成, 并能创造工程经济效益和奇迹.  相似文献   

The WTO and the Kyoto Protocol: interaction issues     

Thomas L. Brewer 《Climate Policy》2013,13(1):3-12

Abstract

This article builds upon the broad survey of climate-trade interactions in Part 1, by focusing upon the specific issues in the interaction of the WTO and the Kyoto Protocol.¹ It classifies the various issues into three groups according to their potential to cause problems and relative urgency. The article gives special attention to issues that are problematic because of the likelihood of occurrence of specific conflicts and the significance of their economic and/or political consequences. It concludes that although there are many interactions that are not problematic and some that offer the potential for win—win outcomes, the possibility of offsetting border measures that could be applied against energy-intensive imports from the USA may become a particularly nettlesome issue.  相似文献