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numerical simulation of mechanisms of deformation,failure and energy dissipation in porous rock media subjected to wave stresses

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Science China(Technological Sciences) 2010年第4期53卷 1098-1113页

作者： JU Yang1,2,WAnG HuiJie1,YAnG YongMing1,HU QinAng3 & PEnG RuiDong1 1 State Key laboratory of Coal Resources and Safe Mining,Beijing Key laboratory of Fracture and Damage Mechanics of Rock and Concrete,China University of Mining and Technology,Beijing 100083,China 2 department of Mechanical and Manufacturing Engineering,University of Calgary,Calgary,Alberta,T2n 1n4,Canada 3 School of Environment and Civil Engineering,College of Engineering,Oklahoma State University,Stillwater,OK 74078,USA State Key laboratory of Coal Resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete China University of Mining and Technology Beijing China department of Mechanical and Manufacturing Engineering University of Calgary Calgary Canada School of Environment and Civil Engineering College of Engineering Oklahoma State University Stillwater USA

The pore characteristics,mineral compositions,physical and mechanical properties of the subarkose sandstones were acquired by means of CT scan,X-ray diffraction and physical tests.A few physical models possessing the same pore characteristics and matrix properties but different porosities compared to the natural sandstones were *** 3D finite element models of the rock media with varied porosities were established based on the CT image processing of the physical models and the MIMICS software *** failure processes of the porous rock media loaded by the split Hopkinson pressure bar(SHPB) were simulated by satisfying the elastic wave propagation *** dynamic responses,stress transition,deformation and failure mechanisms of the porous rock media subjected to the wave stresses were *** is shown that an explicit and quantitative analysis of the stress,strain and deformation and failure mechanisms of porous rocks under the wave stresses can be achieved by using the developed 3D finite element *** applied wave stresses of certain amplitude and velocity,no evident pore deformation was observed for the rock media with a porosity less than 15%.The deformation is dominantly the combination of microplasticity(shear strain),cracking(tensile strain) of matrix and coalescence of the cracked regions around *** stresses lead to microplasticity,while tensile stresses result in cracking of the *** and coalescence of the matrix elements in the neighborhood of pores resulted from the high transverse tensile stress or tensile strain which exceeded the threshold *** simulation results of stress wave propagation,deformation and failure mechanisms and energy dissipation in porous rock media were in good agreement with the physical *** present study provides a reference for analyzing the intrinsic mechanisms of the complex dynamic response,stress transit mode,deformation and failure mechanisms and the disaster mechanism

关键词： porous media three-dimensional finite element model rock media stress wave failure mechanism energy dissipation

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Monitoring and characterization of particle contamination in the pulse compression chamber of the OMEGA EP laser system

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高功率激光科学与工程:英文版 2023年第3期11卷 64-72页

作者： B.n.Hoffman n.Savidis S.G.Demos laboratory for Laser Energetics University of RochesterRochesterNew YorkUSA

The laser-damage performance of optics is known to be negatively affected by microscale particle contamination induced by the operational *** work investigates the properties of particles accumulating in various locations near critical optics inside the OMEGA EP grating compressor chamber during quarterly operational periods over a 2-year *** particles found were characterized using optical microscopy,scanning electron microscopy and energy dispersive X-ray *** analysis indicates significant concentrations of micrometer-to nanometerscale particles inside the vacuum chamber,with higher values observed near the port leading to the OMEGA EP target *** distribution of the chemical composition of these particles varies between collection *** understanding of the mechanisms of particle generation and transport remains uncertain,the hypothesis is that this particle load represents a risk for contaminating the surfaces of high-value optics located inside the chamber,including the compression gratings and deformable mirrors,and therefore affecting their laser-damage resistance and overall operational lifetime.

关键词： laser damage particle contamination

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The Soft X-ray Imager(SXI)on the SMILE Mission

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Earth and Planetary Physics 2024年第1期8卷 5-14页

作者： S.Sembay A.L.Alme D.Agnolon T.Arnold A.Beardmore A.Belén Balado Margeli C.Bicknell C.Bouldin G.Branduardi-Raymont T.Crawford J.P.Breuer T.Buggey G.Butcher R.Canchal J.A.Carter A.Cheney Y.Collado-Vega H.Connor T.Crawford n.Eaton C.Feldman C.Forsyth T.Frantzen G.Galgóczi J.Garcia G.Y.Genov C.Gordillo H-P.Gröbelbauer M.Guedel Y.Guo M.Hailey D.Hall R.Hampson J.Hasiba O.Hetherington A.Holland S-Y.Hsieh M.W.J.Hubbard H.Jeszenszky M.Jones T.Kennedy K.Koch-Mehrin S.Kögl S.Krucker K.D.Kuntz C.Lakin G.Laky O.Lylund A.Martindale J.Miguel Mas Hesse R.nakamura K.Oksavik n.Østgaard H.Ottacher R.Ottensamer C.Pagani S.Parsons P.Patel J.Pearson G.Peikert F.S.Porter T.Pouliantis B.H.Qureshi W.Raab G.Randal A.M.Read n.M.M.Roque M.E.Rostad C.Runciman S.Sachdev A.Samsonov M.Soman D.Sibeck S.Smit J.Søndergaard R.Speight S.Stavland M.Steller TianRan Sun J.Thornhill W.Thomas K.Ullaland B.Walsh D.Walton C.Wang S.Yang School of Physics and Astronomy University of LeicesterLeicesterLE17RHUK Space Park Leicester University of LeicesterLeicesterLE17RHUK Mullard Space Science laboratory University College LondonDorkingRH56NTUK Centre for Electronic Imaging Open UniversityMilton KeynesMK76 AAUK Birkeland Centre for Space Science Department of Physics and TechnologyUniv.of BergenN-5007 BergenNorway University of Vienna A-1010 ViennaAustria Space research Institute Austrian Academy of SciencesA-8042 GrazAustria national Institute of Aerospace Technology MadridSpain ESTEC European Space Agency2201 AZ NoordwijkNetherlands State Key laboratory of Space Weather National Space Science CentreBeijing 100190China University of Applied Sciences and Arts northwestern Switzerland CH-5210 WindischSwitzerland Koegl Space GmbH CH-8157 DielsdorfSwitzerland Space Acoustics GmbH CH-8157 DielsdorfSwitzerland Zurich University of Applied Sciences 8400 WinterhurSwitzerland Genov Solutions N-5172 LoddefjordNorway STM Engineering N-5165 LaksevagNorway John Hopkins University Applied Physics laboratory MD 20723USA nASA/Goddard Space Flight Centre MD 20771USA Center for Space Physics Boston UniversityBostonMA 02215USA department of Theoretical Physics and Astrophysics Masaryk University60177 BrnoCzech Republic Institute of Physics E¨otvo¨s Lor´and University1053 BudapestHungary Aerospace Information research Institute Chinese Academy of SciencesBeijing 100045China Centro de Astrobiologia(CAB) CSIC-INTAMadridSpain

The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)*** is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in *** is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE *** is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s *** provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field *** sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many *** is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.

关键词： Soft X-ray Imaging micropore optics large area CCD

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Synthesis and Crystal Structure of Cu( Ⅱ ) Adduct with n-(4-Chlorophenyl)aza 15-Crown-5

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Chemical research in Chinese Universities 1991年第1期7卷 1-5页

作者： Yan Shiping Wang Genglin (department of Chemistry, nankin University, Tianjin)Yao Xinkan Wang Honggen (Central laboratory, nankai University, Tianjin)

The title compound C18 H25 nC4ClBr2Cu crystallizes in space group P 1 with a = 1.0105(2)nm b=1.0821(1) nm, c=1. 1007(2) nm, a=80. 00(1)°,β=80. 26(1)° γ=77. 83(1)°. Z=2, D = 1. 831 g/cm3, μ=62. 658 cm-1(Mok(?)). The final refinement converged to R=0. 031 for 2547 independent observed reflections. The complex molecule consists of two cationic moieties (HL)+ and an anion which appears as a bromide-bridged copper dimer (Cu2Br6)2-. This structural characterization seems to be rare in metal complexes with crown-ether.

关键词： Crown-ether Copper complex Crystal structure

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Liver X receptor agonist T0901317 reduces atherosclerotic lesions in apoE^(-/-) mice by up-regulating nPC1 expression

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Science China(Life Sciences) 2008年第5期51卷 418-429页

作者： OU Xiang1,2, DAI XiaoYan1, LOnG ZhiFeng3, TAnG YaLing1, CAO DongLi1, HAO XinRui1, HU YanWei1, LI XiaoXu1 & TAnG ChaoKe1 1 Institute of Cardiovascular research, Key laboratory for Atherosclerology of Hunan Province, University of South China, Heng- yang 421001, China 2 department of Physiology, Medical College of Shaoguan University, Shaoguan 512026, China 3 department of Histology and Embryology, University of South China, Hengyang 421001, China Institute of Cardiovascular research Key Laboratory for Atherosclerology of Hunan Province University of South China Hengyang China department of Physiology Medical College of Shaoguan University Shaoguan China department of Histology and Embryology University of South China Hengyang China

In this study, we studied the effect of liver X receptor (LXR) agonist T0901317 on niemann-Pick C1 protein (nPC1) expression in apoE-/- mice. Male apoE-/- mice were randomized into 4 groups, baseline group (n=10), control group (n=14), treatment group (n=14) and prevention group (n=14). All of the mice were fed with a high-fat/high-cholesterol (HFHC) diet containing 15% fat and 0.25% cholesterol. The baseline group treated with vehicle was sacrificed after 8 weeks of the diet. The control group and the prevention group were treated with either vehicle or T0901317 daily by oral gavage for 14 weeks. The treatment group was treated with vehicle for 8 weeks, and then was treated with the agonist T0901317 for additional 6 weeks. Gene and protein expression was analyzed by real-time quantitative PCR, immunohistochemistry and Western blotting, respectively. Plasma lipid concentrations were measured by commercially enzymatic methods. We used RnA interference technology to silence nPC1 gene expression in THP-1 macrophage-derived foam cells and then detected the effect of LXR agonist T0901317 on cholesterol efflux. Plasma triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and apoA-I concentrations were markedly increased in T0901317-treated groups. T0901317 treatment reduced the aortic atherosclerotic lesion area by 64.2% in the prevention group and 58.3% in the treatment group. LXR agonist treatment increased nPC1 mRnA expression and protein levels in the small intestine, liver and aorta of apoE-/- mice. Compared with the normal cells, cholesterol efflux of siRnA THP-1 macrophage-derived foam cells was significantly decreased, whereas cholesterol efflux of LXR agonist T0901317-treated THP-1 macrophage-derived foam cells was significantly increased. Our results suggest that LXR agonist T0901317 inhibits atherosclerosis development in apoE-/- mice, which is related to up-regulating nPC1 expression.

关键词： niemann-Pick C1 protein liver X receptor agonist atherosclerosis plaque

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Effect of UV Irradiation on PAn Precursor Fibers and Stabilization Process

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Journal of Wuhan University of Technology(materials Science) 2011年第3期26卷 449-454页

作者：袁慧五 department of Chemistry and Material Naval University of Engineering

A low-cost rout for modification the polyacrylontrile（PAn） precursor fibers was *** approach involved pretreatment PAn precursor fibers with UV irradiation for various periods of time before the fibers were *** effect of UV irradiation on the chemical structure,orientation factor,density,crystallite size and morphology of the fibers in the process of stabilization was characterized by use of fourier transform infrared spectroscopy（FTIR）,float-sink procedure,X-ray diffraction（XRD）,scanning electron microscope（SEM）,*** results showed that UV irradiation could increase the density of the fibers in stabilization *** analysis indicated that the cyclization of nitrile groups was initiated at room temperature by UV *** transformation of C≡n groups to C=n ones was accelerated in the process of *** orientation factor of irradiated fibers was also *** crystallite size was decreased at first and increased later,and the better irradiation time of UV was 3 min according to the XRD *** analysis indicated that irradiation could decrease the internal and surface defects of the stabilized fibers treated at 300 ℃.

关键词： PAn precursor fibers UV irradiation cyclization crystallite size morphology

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Attention and available long-term memory in an activation-based model

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Science China(Life Sciences) 2010年第6期53卷 743-752页

作者： LIU ZhaoMin1,GUO ChunYan2,3 & LUO Liang4 1 School of Sociology,China University of Political Science and Law,Beijing 102249,China 2 Beijing Key laboratory of Learning and Cognition,department of Psychology,Capital normal University,Beijing 100048,China 3 Key laboratory of Mental Health,Chinese Academy of Sciences,Beijing 100101,China 4 State Key laboratory of Cognitive neuroscience and Learning,Beijing normal University,Beijing 100875,China School of Sociology China University of Political Science and Law Beijing China Beijing Key laboratory of Learning and Cognition Department of Psychology Capital Normal University Beijing China Key laboratory of Mental Health Chinese Academy of Sciences Beijing China State Key laboratory of Cognitive neuroscience and Learning Beijing Normal University Beijing China

The influence of attention on memorizing related items and on available long-term memory (ALTM) was explored,showing that n400 of no-memory items was more negative than that of the memory *** results of the category comparison task indicated that information processing under attention-driven in WM determined the availability of related long-term memory,i.e.,specific content,which was formerly concerned or ignored,yielding different indirect semantic priming *** indicate that the orientation of conceptual attention leads the related representations of LTM to diverse activation patterns,supporting the activation-based model.

关键词： activation-based model attention available long-term memory event-related potentials

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OPTIMAL MODE OF SEDIMEnT TRAnSPORT BY SHALLOW FLOWS In UPLAnD AREAS

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International Journal of Sediment research 2000年第2期 260-267页

作者： D. PAL S. n. PRASAD (department of Civil Engineering, University of Mississippi, University, MS 38677, USA.) M. J. M. ROMKEnS(USDA ARS national Sedimentation laboratory, Oxford, MS 38655, USA.)

Soil erosion and sediment movement are serious problems of upland areas of a watershed. In these areas,most of the eroded sediment is transported in overland flows; either in shallow or in concentrated flowsituations. These flows are usually associated with nonlinear waves, generally known as "roll waves" inthe hydraulic engineering literature. Under suitable hydraulic conditions, these waves contain a significantfraction of the total kinetic energy of the flow regime. Hence, the waves act as the primary energy sourcein transporting eroded sediment in shallow flows on steep slopes. Our laborat0ry experiments undercontrolled condition suggest that modulation of the roll waves is effected by the addition of increasingamouflts of sediment in the flow. The optimal condition in the sediment transport rate is reached whenmost of the available wave energy is consumed in carrying the sediment. A related set of experiments ongravitational flows of dry granular material show that the evolving scales of sediment waves are intrinsicto the transport mechanism of the solid phase.

关键词： Upland areas Sediment transport Shallow flows Wave modes Granular organization

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novel ^(99m)Tc labeled σ r eceptor ligand as a potential tumorimaging agent

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Science China Chemistry 2006年第2期49卷 169-176页

作者： FAn Caiyun1, JIA Hongmei1, Deuther-Conrad Winnie2, Brust Peter2, Steinbach J?rg2 & LIU Boli1 1. Key laboratory of Radiopharmaceuticals (Beijing normal University), Ministry of Education, department of Chemistry, Beijing normal University, Beijing 100875, China 2. Institute of Interdisciplinary Isotope research, Permoserstr. 15, 04318 Leipzig, Germany Correspondence should be addressed to Liu Boli Key laboratory of Radiopharmaceuticals (Beijing normal University) Ministry of Education Department of Chemistry Beijing Normal University Beijing China Institute of Interdisciplinary Isotope research Leipzig Germany

A novel 99mTc labeled complex, [n-[2-((2-oxo-2-(4-(3-phenylpropyl)piperazin-1-yl)ethyl) (2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato]Technetium(V) oxide (PPPE-MAMA′-99mTcO) ([99mTc]-2) has been designed and prepared based on the integrated approach. The corresponding rhenium complex (PPPE-MAMA′-ReO)(Re-2) has been prepared and characterized. In vitro competi-tion binding assays show moderate affinity of Re-2 towards σ1 and σ2 receptors with Ki values of 8.67 ± 0.07 and 5.71 ± 1.88 μmol, respectively. Planar images obtained at 0.5 h, 4 h, 20 h after i.v. in-jection indicate the accumulation of [99mTc]-2 in MCF-7 human breast tumor bearing mice at 20 h. Furthermore, the accumulation of [99mTc]-2 has been inhibited at 20 h after co-injection of [99mTc]-2 plus haloperidol (1 mg/kg). Biodistribution studies of [99mTc]-2 display an in vivo tumor uptake of 0.14% ± 0.01% ID/g at 24 h post i.v. injection with a tumor/muscle ratio of 6.02 ± 0.87. The above results suggest that [99mTc]-2, derived from a previously published lead compound, retains certain tumor uptake and affinity for σ receptors. [99mTc]-2 may be used as a basis for further structural modifications to develop tumor imaging agents with high affinity for σ receptors.

关键词：肿瘤 σ受体 SPECT ^(99m ) Tc

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Coupling Ensemble Kalman Filter with Four-dimensional Variational Data Assimilation

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Advances in Atmospheric Sciences 2009年第1期26卷 1-8页

作者： Fuqing ZHAnG Meng ZHAnG James A. hansen department of Meteorology Pennsylvania State University University Park Pennsylvania USA navy research laboratory Monterrey California USA

This study examines the performance of coupling the deterministic four-dimensional variational assimilation system （4DVAR） with an ensemble Kalman filter （EnKF） to produce a superior hybrid approach for data assimilation. The coupled assimilation scheme （E4DVAR） benefits from using the state-dependent uncertainty provided by EnKF while taking advantage of 4DVAR in preventing filter divergence： the 4DVAR analysis produces posterior maximum likelihood solutions through minimization of a cost function about which the ensemble perturbations are transformed, and the resulting ensemble analysis can be propagated forward both for the next assimilation cycle and as a basis for ensemble forecasting. The feasibility and effectiveness of this coupled approach are demonstrated in an idealized model with simulated observations. It is found that the E4DVAR is capable of outperforming both 4DVAR and the EnKF under both perfect- and imperfect-model scenarios. The performance of the coupled scheme is also less sensitive to either the ensemble size or the assimilation window length than those for standard EnKF or 4DVAR implementations.

关键词： data assimilation four-dimensional variational data assimilation ensemble Kalman filter Lorenz model hybrid method

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