检索结果-南通市图书馆

Subduction-Modified Subcontinental Mantle in South China: Trace Element and Isotope Evidence in Basalts from Hainan Island

在线全文

学校读者我要写书评

暂无评论

Chinese journal Of Geochemistry 1996年第1期15卷 1-19页

作者：张明涂勘解广轰 MARTINF.j.FLOWER Department of Geological Sciences University of Illinois at Chicago Chicago USA Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou P.R.C.

Cenozoc lavas from Hainan Island, bouth China, comprise quartz tholeiite. olivinethoeiite, alkali basalt, and basanite and form a continuous, thoeiite-dominated, comopitionalspectrum. Highly incompatible elements and their relationships with isotope in these lavas areshown to be useful in evaluating mantle-source composition, whereas modeling suggests that ra-tios of elements with bulk partition coefficients significantly larger than those of Nb and Ta maybe sensitive to patial melting. Th/Ta and La/Nb ratios of alkali basalts are lower than those ofthoeiites, and they are all fower than tbe of the primitive mantle. These ratios correlate posi-tively with 207Pb/204Pb and 87Sr/86Sr ratios. Such relatioships can be explained by mixing ofdepleted and enriched source componentS. A depleted component is indicated by alkali basaltcompositions and is similar to some depleted OIB (PREMA). The enriched component, similarto sediment compositios, is indicated by tholeiites with high LILE/HFSE, 207Pb/204Pb, and87/86Sr *** general, basalts from Hainan and the South China Basin (SCB) share common geo-chemical charcters, e.g. high Rb/Sr, Th/Ta, 207Pb/206Pb, and low Ba/Th ratios. Such ageochemical trend is comparable to that of EMII-type OIB and best explained as the result ofsubduction. Occurrence of these charcteristics in both continennd Hainan basalts and SCBseamount basalts indicates the presence of a South China geochemical domain that exists in themantle region below the lithosphere.

关键词：海南岛玄武岩华南地区示踪元素同位素

Triviality of Quantum Electrodynamics Revisited

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第3期69卷 263-265页

作者： D.Djukanovic j.Gegelia Ulf-G.Meiβner Helmholtz Institute Mainz University of MainzD-55099 MainzGermany Institute for Advanced Simulation Institut flit Kernphysik and Julich Center for Hadron PhysicsForschungszentrum JulichD-52425 JfilichGermany Tbilisi State University 0186 TbilisiGeorgia Helmholtz Institut fiir Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universitat BonnD-53115 BonnGermany

Quantum electrodynamics is often considered to be a trivial *** is based on a number of evidences,both numerical and *** of the strong indications for triviality of QED is the existence of the Landau pole for the running *** show that by treating QED as the leading order approximation of an effective field theory and including the next-to-leading order corrections,the Landau pole is *** also analyze the cutoff dependence of the bare coupling at two-loop order and conclude that the conjecture,that for reasons of self-consistency,QED needs to be trivial is a mere artefact of the leading order approximation to the corresponding effective field theory.

关键词： theory of quantized fields renormalization photons

The evidence for natural therapeutics as potential anti-scarring agents in burn-related scarring

在线全文

学校读者我要写书评

暂无评论

Burns & Trauma 2016年第2期4卷 78-89页

作者： M.Mehta O.A.Branford K.j.Rolfe British College of Osteopathic Medicine(BCOM) Finchley RoadLondon NW35HRUK The Royal Marsden Hospital Fulham RdLondon SW36JJUK

Though survival rate following severe thermal injuries has improved,the incidence and treatment of scarring have not improved at the same *** review discusses the formation of scars and in particular the formation of hypertrophic ***,though there is as yet no gold standard treatment for the prevention or treatment of scarring,a brief overview is included.A number of natural therapeutics have shown beneficial effects both in vivo and in vitro with the potential of becoming clinical therapeutics in the *** natural therapeutics include both plant-based products such as resveratrol,quercetin and epigallocatechin gallate as examples and includes the non-plant-based therapeutic *** review also includes potential mechanism of action for the therapeutics,any recorded adverse events and current administration of the therapeutics *** review discusses a number of potential'treatments'that may reduce or even prevent scarring particularly hypertrophic scarring,which is associated with thermal injuries without compromising wound repair.

关键词： Burns Hypertrophic scar Natural therapeutics Wound healing

PIV measurements of turbulent jets issuing from triangular and circular orifice plates

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第6期56卷 1176-1186页

作者： XU MinYi ZHANG jianPeng MI jianChun NATHAN G j KALT P A M Marine Engineering College Dalian Maritime University State Key Laboratory of Turbulence & Complex Systems College of EngineeringPeking University Centre for Energy Technology and School of Mechanical Engineering University of AdelaideSA 5005Australia

The present study experimentally investigated the near-field flow mixing characteristics of two turbulent jets issuing from equilateral triangular and circular orifice plates into effectively unbounded surroundings,*** particle image velocimetry(PIV) was applied to measure the velocity field at the same Reynolds number of Re=50,000,where Re = UeDe /with Ue being the exit bulk velocity and the kinematic viscosity of fluid,D e the equivalent *** instantaneous velocity,mean velocity,Reynolds stresses were *** the mean velocity field,the centreline velocity decay rate and half-velocity width were *** the mixing characteristics of the two jets,it is found that the triangular jet has a faster mixing rate than the circular *** triangular jet entrainments with the ambient fluid at a higher rate in the near *** is evidenced by a shorter unmixed core,faster Reynolds stress and centreline turbulence intensity *** primary coherent structures in the near field are found to break down more rapidly in the triangular jet as compared to the circular *** the entire measurement region,the triangular jet maintained a higher rate of decay and ***,all components of Reynolds stress of the triangular jet appear to reach their peaks earlier,and then decay more rapidly than those of the circular *** addition,the axis-switching phenomenon is observed in the triangular jet.

关键词： triangular jet turbulent mixing coherent structures axis-switching

Point-based tool representations for modeling complex tool shapes and runout for the simulation of process forces and chatter vibrations

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2018年第3期6卷 301-307页

作者： P. Wiederkehr T. Siebrecht j. Baumann D. Biermann Institute of Machining Technology TU Dortmund University Dortmund Germany Virtual Machining Department of Computer Science TU Dortmund University Dortmund Germany

Geometric physically-based simulation systemscan be used for analyzing and optimizing complex millingprocesses, for example in the automotive or aerospaceindustry, where the surface quality and process efficiencyare limited due to chatter vibrations. Process simulationsusing tool models based on the constructive solid geometry（CSG） technique allow the analysis of process forces, tooldeflections, and surface location errors resulting from five-axis machining operations. However, modeling complextool shapes and effects like runout is difficult using CSGmodels due to the increasing complexity of the shapedescriptions. Therefore, a point-based method for modelingthe rotating tool considering its deflections is presented inthis paper. With this method, tools with complex shapesand runout can be simulated in an efficient and flexibleway. The new modeling approach is applied to exemplarymilling processes and the simulation results are validatedbased on machining experiments.

关键词： Modeling Tool geometry Milling

Phospholipase D inhibition by hexanal is associated with calcium signal transduction events in raspberry

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Horticulture Research 2017年第1期4卷 154-162页

作者： Walid El Kayal Gopinadhan Paliyath j Alan Sullivan jayasankar Subramanian Department of Plant Agriculture University of Guelph-Vineland Station4890 Victoria Avenue NVinelandL0R2E0OntarioCanada Department of Plant Agriculture University of GuelphGuelphN1G2W1OntarioCanada

Raspberry(Rubus spp.)is an economically important crop with a restricted growing season and very limited fruit shelf-life due to its extreme *** order to prolong its shelf life,an aqueous composition containing hexanal as the key active ingredient(HC)was applied as a preharvest spray during fruit *** effects of HC were assessed using physiological,biochemical and anatomical parameters on the treated fruits and compared with the effects of mock inoculation which lacked *** and acidity did not show a significant change in response to HC treatment,while the pulling force(the tension required to detach the berry from the receptacle)significantly improved in the HC-treated fruits,compared to *** electron microscope(SEM)analysis revealed a high correlation between the presence of rigid epidermal hairs and a stronger degree of attachment between berries and their receptacle in the HC treated ***,electron micrographs also showed abnormal crystalline depositions on the epidermal drupelets of the treated *** Dispersive X-ray Spectroscopy(EDS)analysis showed those crystals to be largely composed of *** treatment also resulted in the reduction of transcript level of three phospholipase D genes,as well as altered expression pattern of five members of the annexin gene family,and four calmodulin-binding transcription *** of PLD activity showed that hexanal inhibited PLD activity in treated *** potential crosstalk between hexanal,phospholipase D activity and calcium and this crosstalk’s role in delaying fruit softening and in prolonging storage life of fruits shelf life is discussed.

关键词： inhibited extreme restricted

Engineering Novel Molecular Beacon Constructs to Study Intracellular RNA Dynamics and Localization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2017年第5期15卷 279-286页

作者： Zhao Ma Xiaotian Wu Christopher j.Krueger Antony K.Chen Department of Biomedical Engineering College of Engineering Peking University Beijing 100871 China Wallace H Coulter Department of Biomedical Engineering Georgia Institute of Technology Atlanta GA 30332 USA

With numerous advancements in novel biochemical techniques, our knowledge of the role of RNAs in the regulation of cellular physiology and pathology has grown significantly over the past several decades. Nevertheless, detailed information regarding RNA processing, trafficking, and localization in living cells has been lacking due to technical limitations in imaging single RNA transcripts in living cells with high spatial and temporal resolution. In this review, we discuss tech- niques that have shown great promise for single RNA imaging, followed by highlights in our recent work in the development of molecular beacons （MBs）, a class of nanoscale oligonucleotide-probes, for detecting individual RNA transcripts in living cells. With further refinement of MB design and development of more sophisticated fluorescence microscopy techniques, we envision that MB-based approaches could promote new discoveries of RNA functions and activities.

关键词： Y-O-methyl RNA Phosphorothioate Molecular beacon RNA dynamics Single-molecule RNAimaging

Irradiation uniformity at the Laser Megajoule facility in the context of the shock ignition scheme

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2014年第2期2卷 1-12页

作者： Mauro Temporal Benoit Canaud Warren j. Garbett Rafael Ramis Stefan Weber Centre de Math'ematiques et de Leurs Applications ENS Cachan and CNRS 61 Av. du President Wilson Cachan Cedex France CEA DIF Arpajon Cedex France AWE plc Aldermaston Reading Berkshire United Kingdom ETSI Aeron'auticos Universidad Polit'ecnica de Madrid Madrid Spain ELI-Beamlines Institute of Physics Academy of Sciences of the Czech Republic Prague Czech Republic

The use of the Laser Megajoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion capsule in the context of the shock ignition scheme providing the energy gain and an estimation of the increase of the peak power due to the reduction of the photon penetration expected during the high-intensity spike pulse. In the second part, we considered a Laser Megajoule configuration consisting of 176 laser beams that have been grouped providing two different irradiation schemes. In this configuration the maximum available energy and power are 1.3 Mj and 440 TW. Optimization of the laser–capsule parameters that minimize the irradiation non-uniformity during the first few ns of the foot pulse has been performed. The calculations take into account the specific elliptical laser intensity profile provided at the Laser Megajoule and the expected beam uncertainties. A significant improvement of the illumination uniformity provided by the polar direct drive technique has been demonstrated. Three-dimensional hydrodynamic calculations have been performed in order to analyse the magnitude of the azimuthal component of the irradiation that is neglected in twodimensional hydrodynamic simulations.

关键词： inertial confinement fusion shock ignition laser system

A New Ceratopsian from the Upper jurassic Houcheng Formation of Hebei, China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2006年第4期80卷 467-473页

作者： ZHAO Xijin CHENG Zhengwu XU Xing Peter j. MAKOVICKY Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences 142 Xizhimenwai Street Beijing 100044 China Institute of Geology Chinese Academy of Geological Sciences 26 Baiwanzhuang Road Beijing 100037 China Department of Geology The Field Museum 1400 S Lake Shore Drive Chicago IL 60605 U.S.A.

A new ceratopsian taxon Xuanhuaceratops niei gen. et sp. nov. is erected based on four fragmentary specimens collected from the Late jurassic Houcheng Formation, Hebei Province, China. Xuanhuaceratops shares a number of derived features with, and is closely related to, another probable Late juarassic ceratopsian Chaoyangsaurus youngi, from which it differs in only possessing a single premaxlllary tooth as well as in details of quadrate and scapular morphology. We hypothesize that these two taxa represent a primitive lineage of Ceratopsia that is basal to the psittacosauridneoceratopsian diversity, and propose the name Chaoyangsauridae for it.

关键词： Houcheng Formation jurassic Hebei Chaoyangsauridae Ceratopsia