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Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North Pacific

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Science China Earth Sciences 2004年第3期47卷 280-288页

作者： Erwin suess Dirk Rickert Department of Marine Environmental Geology Research Centre of Marine Geology University of Kiel Kiel D-24148 Germany Department of Marine Environmental Geology Research Centre of Marine Geology University of Kiel Kiel D-24148 Germany

Characteristic gypsum micro-sphere and granular mass were discovered by bin-ocular microscope in the gas hydrate-associated sediments at cores SO143-221 and SO143/TVG40-2A respectively on Hydrate Ridge of Cascadia margin, the eastern North Pacific. XRD patterns and EPA analyses show both micro-sphere and granular mass of the crystals have the typical peaks and the typical main chemical compositions of gypsum, although their weight percents are slightly less than the others in the non-gas hydrate-associated marine regions. SEM pictures show that the gypsum crystals have clear crystal boundaries, planes, edges and cleav-ages of gypsum in form either of single crystal or of twin crystals. In view of the fact that there are meanwhile gas hydrate-associated authigenic carbonates and SO42--rich pore water in the same sediment cores, it could be inferred reasonably that the gypsums formed also authigenically in the gas hydrate-associated environment too, most probably at the interface between the down-ward advecting sulfate-rich seawater and the below gas hydrate, which spilled calcium during its formation on Hydrate Ridge. The two distinct forms of crystal intergrowth, which are the granular mass of series single gypsum crystals at core SO143/TVG40-2A and the microsphere of gypsum crystals accompanied with detrital components at core SO143-221 respectively, indicate that they precipitated most likely in different interstitial water dynamic environments. So, the distinct authigenic gypsums found in gas hydrate-associated sediments on Hydrate Ridge could also be believed as one of the parameters which could be used to indicate the presence of gas hydrate in an unknown marine sediment cores.

关键词： authigenic gypsum, gas hydrate-associated sediment, Hydrate Ridge, eastern North Pacific.

Indicators of δ^(13)C and δ^(18)O of gas hydrate-associated sediments

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Chinese Science Bulletin 2002年第19期47卷 1659-1663页

作者： E. suess Faculty of Earth Sciences China University of Geosciences Wuhan China Department of Marine Environmental Geology GEOMAR University of Kiel Kiel Germany

The analyses of δ13C and δ18O of gas hydrate-associated sediments from two cores on Hydrate Ridge in Cascadia convergent margin offshore Oregon, eastern North Pacific show the values of δ13C from-29.81‰ to -48.28‰(PDB) and δ18O from 2.56‰to 4.28‰ (PDB), which could be plotted into a group called typical carbonate minerals influenced by the methane in cold venting. Moreover, the values of δ13C and δ18O show a consistent trend in both cores from top to bottom with increasing of δ13C and decreasing of δ18O. This trend could be explained as an effect caused by the anaerobic oxidation of methane (AOM) in depth and the oxygen fraction during the formation of gas hydrate in depth together. These characteristics of δ13C and δ18O indicate that the gas hydrate-associated sediments are significantly different from the normal marine carbonates, and they are deeply influenced by the formation and evolution of gas hydrate. So, the distinct characteristics of δ13C and δ18O of gas hydrate-associated

关键词： gas hydrate associated sediments δ13C and δ18O indi-cators.

Hybrid system-a promising way solving future energy problems

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航空动力学报 2007年第4期22卷 565-576页

作者： dieter Bohn Institute of Steam and Gas Turbines RWTH Aachen University

With the increasing demand for electricity,an efficiency improvement and thereby reduced CO2 emissions of the power plants are expected in order to reach the goals set in the Kyoto *** comparison to conventional systems,the hybrid-systems with the use of synergetic effects offer the possibility to provide a substantial contribution to spare our natural resources and protect our *** Cycle Power Plants belongs innately hybrid system in the centralized energy *** can provide large amounts of power and have a quick start-up *** MGT/FC hybrid system is quite promising in the decentralized energy *** is widely used in stand-alone ***,the combination of fossil and renewable power plant technologies contains a large synergy potential to increase the efficiency of processes for power *** materials,innovative cooling technology,new combustion concepts and optimized production methods are needed to make the potential of these new technologies accessible for a quantum leap in the *** this it needs considerable research work and good coordinated research projects between the state,industry,research laboratories and universities.

关键词：航空推进系统混合燃料涡轮机能源

Designing a power plant with highest efficiency:results from SFB 561

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航空动力学报 2009年第4期24卷 717-728页

作者： dieter Bohn Institute of Steam and Gas Turbines RWTH Aachen University

The goal of Collaborative Research Centre(SFB) 561 "thermally highly loaded,porous and cooled multi-layer systems for combined cycle power plants" is to expand the current technological and scientific knowledge on power plants in order to achieve total efficiencies of 65% in a combined cycle power plant in the year ***,the aero-thermomechanical,structural-mechanical,materials' scientific and production fundamentals for the development of steam and gas turbine components that are able to withstand highest thermal loads are being worked out within this *** means for the gas turbine that combustion chamber outlet temperatures of 1520℃ at 1.7MPa are to be *** order to control these high temperatures,it is not only required to develop new materials' solutions,including thermal barrier coatings,but also to apply improved cooling techniques,as for example effusion *** novel cooling concept is to be realised through open-porous *** structures can consist of drilled open-porous multi-layer systems or open-porous metallic *** development of graded multi-layer systems is also extremely important,as the grading will enable the use of coolant in dependence of the *** live steam parameters in the high pressure turbine are expected to be increased up to approximately 700℃ with pressure of *** elevated steam parameters can be encountered with Ni-base alloys,but this is a costly alternative,associated with many manufacturing ***,the SFB proposes cooling the highly loaded turbines instead,as this would necessitate the application of far less Ni-base *** protect the thermally highly loaded casing,a sandwich material consisting of two thin face sheets with a core of a woven wire mesh is used to cover the walls of the steam turbine *** current state of the research shows that by utilising innovative cooling technologies a total efficiency of 65% can be reached without exceeding the m

关键词： gas turbine steam turbine cooling novel materials process calculation

The Vγ4/butyrophilin conspiracy: novel role of intraepithelial γδ T cells in chronic inflammatory bowel disease

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Signal Transduction and Targeted Therapy 2023年第12期8卷 5575-5577页

作者： dieter Kabelitz Institute of Immunology Christian-Albrechts University Kiel and University Hospital Schleswig-Holstein Campus KielKielGermany

In a recent article published in Science,Dart and colleagues reported that colonic T cells expressing the Vγ4 T-cell receptor(TCR)interact with epithelial butyrophilin-like(BTNL)proteins BTNL3 and BTNL8 in healthy individuals,and they observed a depletion of Vγ4 T cells in inflammatory bowel diseases with renormalization associated with disease remission.1 This paper identifies the BTNL/Vγ4 axis as a new disease modifier in IBD.

关键词： bowel inflammatory diseases

Welding mechanics for advanced component safety assessment

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Frontiers of Materials Science 2011年第2期5卷 224-235页

作者： dieter SIEGELE Fraunhofer Institute for Mechanics of Materials IWM WShlerstr. 11 79108 Freiburg Germany

Numerical methods are nowadays a useful tool for the calculation of distortion and residual stresses as a result from the welding process. Modern finite element codes not only allow for calculation of deformations and stresses due to the welding process but also take into account the change of microstructure due to different heating and cooling rates. As an extension to the pure welding simulation, the field of welding mechanics combines the mechanics and the material behaviour from the welding process with the assessment of service behaviour of welded components. In the paper, new results of experimental and numerical work in the field of welding mechanics are described. Through examples from automotive, nuclear and pipe-line applications it is demonstrated that an equilibrated treatment and a close interaction of ＂process＂, ＂properties＂ and ＂defects＂ are necessary to come up with an advanced fitness-forservice assessment of welded components.

关键词： welding simulation residual stress defect assessment fracture mechanics

Lab experiments on the innovative rapid thick strip casting process

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International Journal of Minerals,Metallurgy and Materials 2012年第5期19卷 391-398页

作者： Richard Nagy dieter Senk Department of Ferrous Metallurgy IEHK RWTH Aachen UniversityAachen 52056Germany

Rapid thick strip casting （RTSC） by Anton Hulek, Inventmetall, is an innovative concept for the production of hot strips with a final as-cast thickness of about 25 mm before rolling. The innovation of the mechanism consists in a vertical mould performing a caterpillar motion. This moving mould has an unconventional parallelogram-shaped cross-section. The conventional rectangular shape is formed in the shaping machine, which is placed straight below the mould. Further elements of the technology are state-of-the-art. For the investigation of this new casting system theoretical calculations were complemented with practical experiments. The investigation focused mainly on two key aspects： the characteristics of the mould and the shaping process. For the practical analysis a static mould with three pairs of elements in laboratory scale was developed and commissioned by the Dept. of Ferrous Metallurgy @ RWTH Aachen University. The shaping experiments were carried out in model scale with two different materials and in variable boundary conditions. The results of these experiments delivered important mechanical as well as thermal informations about the casting system.

关键词： continuous casting rapid solidification strip metal moulds near-net-shape casting

Natural water purification and water management by artificial groundwater recharge

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第3期9卷 221-226页

作者： Klaus-dieter BALKE Institute for Geosciences University of TübingenSigwartstr.10D-72076 TübingenGermany

Worldwide,several regions suffer from water scarcity and *** infiltration and subsurface storage of rain and river water can reduce water *** groundwater recharge,possibly combined with bank filtration,plant purification and/or the use of subsurface dams and artificial aquifers,is especially advantageous in areas where layers of gravel and sand exist below the earth's *** infiltration of surface water into the uppermost aquifer has qualitative and quantitative *** contamination of infiltrated river water will be reduced by natural *** minerals,iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination *** this,a final water treatment,if necessary,becomes much easier and *** quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water *** changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water *** method enables a continuous water supply over the whole ***,artificially recharged groundwater is better protected against pollution than surface water,and the delimitation of water protection zones makes it even more save.

关键词： Artificial groundwater recharge Natural attenuation Water management

Eigenvalue sensitivity analysis based on the transfer matrix method

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International Journal of Mechanical System Dynamics 2021年第1期1卷 96-107页

作者： dieter Bestle Engineering Mechanics and Vehicle Dynamics Brandenburg University of Technology Cottbus‐SenftenbergCottbusGermany

For linear mechanical systems,the transfer matrix method is one of the most efficient modeling and analysis ***,in contrast to classical mod-eling strategies,the final eigenvalue problem is based on a matrix which is a highly nonlinear function of the ***,classical strategies for sensitivity analysis of eigenvalues *** parameters cannot be *** paper develops two specific strategies for this situation,a direct differentiation strategy and an adjoint variable method,where especially the latter is easy to use and applicable to arbitrarily complex chain or branched multibody *** the system analysis itself,it is able to break down the sensitivity analysis of the overall system to analytically determinable derivatives of element transfer matrices and recursive formula which can be applied along the transfer path of the topology *** examples of different complexity validate the proposed approach by comparing results to analytical calculations and numerical *** obtained procedure may support gradient‐based optimization and robust design by delivering exact sensitivities.

关键词： adjoint variable method direct differentiation sensitivity analysis transfer matrix method