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Conceptual design of an ex.eriment to study dust destruction by astrophysical shock waves

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High Power Laser Science and engineering 2018年第3期6卷 9-14页

作者： M. J.-e. Manuel T. Temim e. Dwek A. M. Angulo e x. belanc.urt.r. e drake C. C. Kuranz M. J. MacDonald B. A. remington General Atomics 3550 General Atomics Court San Diego CA 92121 USA Space Telescope Science Institute 3700 San Martin Drive Baltimore MD 21218 USA Observational Cosmology Lab Code 665 NASA Goddard Space Flight Center Greenbelt MD 20771 USA Climate and Space Science and engineering University of Michigan Ann Arbor M148109 USA Department of Physics University of California Berkeley CA 94720 USA Lawrence Livermore National Laboratory Livermore CA 94450 USA

A novel laboratory ex.erimental design is described that will investigate the processing of dust grains in astrophysical shocks. Dust is a ubiquitous ingredient in the interstellar medium(ISM) of galax.es; however, its evolutionary cycle is still poorly understood. especially shrouded in mystery is the efficiency of grain destruction by astrophysical shocks generated by ex.anding supernova remnants. While the evolution of these remnants is fairly well understood, the grain destruction efficiency in these shocks is largely unknown. The ex.eriments described herein will fill this knowledge gap by studying the dust destruction efficiencies for shock velocities in the range ～10–30 km/s(μm/ns), at which most of the grain destruction and processing in the ISM takes place. The ex.eriments focus on the study of grain–grain collisions by accelerating small(～1 μm) dust particles into a large(～5–10 μm diameter) population; this simulates the astrophysical system well in that the more numerous, small grains impact and collide with the large population. Facilities that combine the versatility of high-power optical lasers with the diagnostic capabilities of x.ray free-electron lasers, e.g., the Matter in ex.reme Conditions instrument at the SLAC National Accelerator Laboratory, provide an ideal laboratory environment to create and diagnose dust destruction by astrophysically relevant shocks at the micron scale.

关键词： laboratory astrophysics shock waves dust destruction

Analytical solutions of uniform ex.ended dislocations and tractions over a circular area in anisotropic magnetoelectroelastic bimaterials

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Acta Mechanica Sinica 2013年第1期29卷 73-84页

作者： Y.-F. Zhao x.-C. Shang e. Pan Dept. of Civil engineering University of Akron Dept. of Applied Mechanics University of Science and Technology

In this paper, we derive the analytical solutions in a three-dimensional anisotropic magnetoelectroelastic bimaterial space subject to uniform ex.ended dislocations and tractions within a horizontal circular area. By virtue of the Stroh formalism and Fourier transformation, the final ex.ression of solutions in the physical domain contains only line integrals over [0, 2π] rather than infinite integrals. As the reduced cases, the half-space and homogeneous full-space solutions can be directly derived from the present solutions. Also, in terms of material domains, the present solutions can be reduced to the piezoelectric, piezomagnetic, purely elastic materials with different symmetries of material prop- erty. To carry out numerical calculations, Gauss quadrature is adopted. In the numerical ex.mples, the effect of different loading locations on the response at the interface is analyzed. It is shown that, when the magnetic traction or electric dislocation is applied, the physical quantities on the interface may not decrease monotonically as the loading area moves away from the interface. The distributions of different in-plane physical quantities on the upper and lower interfaces under various ex.ended horizontal loadings are compared and the differences are discussed. The work presented in this paper can serve as benchmarks for future numerical studies in related research fields.

关键词： Anisotropic bimaterial space. Magnetoelectroe- lastic ex.ended dislocations ex.ended tractions Circular loading Analytic solutions

recent developments of surface complex.tion models applied to environmental aquatic chemistry

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Journal of environmental Sciences 2001年第4期13卷 422-434页

作者： Liu, W.-x. Tang, H.-x. SKLeAC Res. Cntr. Eco-Environmental Sci. Chinese Academy of Sciences Beijing 100085 China

Based on numerous latest references, the current developments in surface complex.tion, surface precipitation and the corresponding models (SCMs and SPMs), were reviewed. The contents involved comparison on surface charge composition and layer-structure of solid-solution interface for the classical 1-pK and 2-pK models. In addition, the fundamental concept and relations of the new models, i. e., multi-site complex.tion (MUSIC) and charge- distribution (CD) MUSIC models were described as well. To avoid misuse or abuse, it must be emphasized that the applicability and limitation for each model should be considered carefully when selecting the concerned model(s). In addition, some new powerful techniques for surface characterization and analysis applied to model establishment and modification were also briefly introduced.

关键词： Complex.tion Precipitation (chemical)

x.T enabled prediction of structure and permeability of flocculated structures and sediments

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2005年第12期6卷 1367-1373页

作者： WILLIAMS r.A. SeLOMULYA C. JIA x. Institute of Particle Science ＆ engineering School of Process Environmental ＆ Materials Engineering University of Leeds Leeds LS2 9JT UK ArC Centre for Functional Nanomaterials School of Chemical Engineering ＆ Industrial Chemistry University of New South Wales Sydney NSW 2052 Australia

3D visualisations of the microstructure of flocculated particulates and sediments using optical confocal laser mi- croscopy and high resolution x.ray microtomography (x.T) methods are described. Data obtained from in-situ measurements should enable direct computation of the properties of solids assembly (shape, size, contact area) and their permeability to fluids. A specific application relating to the formation of silica aggregates is described from which the behaviour of sediments containing these materials can be predicted on the basis of a bench-top test and the use of a Lattice Boltzman simulation. It is proposed that the method can potentially be used to predict trends such as the filtration behaviour of porous structures under different states of compression. This offers a significant benefit in assisting the formulation design of flocculated materials pertinent to a number of industrial sectors wishing to design optimal filtration or relevant operations.

关键词： Fluid flow Imaging Microstructure Porous media Visualization Tomography

First-Principles Study of the Influence of Lattice Misfit on the Behavior and the Ductility effect of Hafnium in Ni-Ni3AI System

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Acta Metallurgica Sinica(english Letters) 2014年第1期27卷 87-94页

作者： Y. Wu J. Guo W. Zhang x. Ma Q. Zhang J. Hou r. Huang x. Liu Institute of Molecular engineering and Applied Chemistry Anhui University of Technology Ma'anshan 243002 China Shenyang National Laboratory for Materials Science Instituteof Metal Research Chinese Academy of SciencesShenyang 110016 China College of Physics Science and Technology Shenyang NormalUniversity Huanghe Street 253 Shengyang 110034 China School of Materials Science and engineering Anhui Universityof Technology Ma'anshan 243002 China

Two Ni/Ni3Al-interface-contained cluster models with/without lattice misfit are studied by first-principles method to clarify the debates about the segregation behaviors of Hafnium （Hf） and ex.lore the influence of lattice misfit on the ductility effect of Hr. It is found that though Hf prefers to substitute A1 rather than Ni in Ni3A1 phase within most of the investigated misfit range, its stronger preferring to Ni phase than NiaA1 phase makes it impossible to go into Ni3A1 phase to occupy A1 site in Ni-Ni3A1 alloys. Bond order analysis in Hf-free case shows that lattice misfit has different effects on the Griffith work of interfacial cleavage 27int/e and the max.mum theoretical shear stress Zmax.of Ni and Ni3A1, contributing to the ex.stence of anomalous strength-temperature phenomena in NiaA1 alloys. However, the addition of Hf will make the 27int/e （or Zmax. of both Ni3A1 and Ni decrease （or increase） with lattice misfit, indicating that the addition of Hf may make the anomalous strength-temperature relationship in Ni3A1 region disappear locally.

关键词： Hafnium Lattice misfit Segregation Ductility

H_∞ fault estimation for a class of linear time-delay systems in finite frequency domain

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Journal of Systems engineering and electronics 2010年第5期21卷 835-841页

作者： Quanchao Dong Maiying Zhong Steven x. Ding School of Control Science and engineering Shandong University Jinan 250061 E R. China School of Instrumentation Science and Opto-electronics engineering Beihang University Beijing 100191 P. R. China Institute for Automatic Control and Complex.Systems University of Duisburg-Essen Duisburg 47057 Germany

This paper deals with the problem of H∞ fault estimation for linear time-delay systems in finite frequency *** a generalized coordinate change is applied to the original system such that in the new coordinates all the time-delay terms are injected by the system＇s input and *** an observer-based H∞ fault estimator with input and output injections is proposed for fault estimation with known frequency *** the aid of Generalized Kalman-Yakubovich-Popov lemma,sufficient conditions on the ex.stence of the H∞ fault estimator are derived and a solution to the observer gain matrices is obtained by solving a set of linear matrix.***,a numerical ex.mple is given to illustrate the effectiveness of the proposed method.

关键词： fault estimation time-delay generalized coordinate change generalized Kalman-Yakubovich-Popov lemma finite frequency domain.

Investigation of turbulence rotation in the SOL and plasma edge of W7-x.for different magnetic configurations

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Plasma Science and Technology 2020年第6期22卷 21-31页

作者： A KrÄMer-FLeCKeN x.HAN M OTTe G ANDA S A BOZHeNKOV D DUNAI G FUCHerT J GeIGer O GrULKe e PASCH e r SCOTT e TrIer M VÉCSeI T WINDISCH S ZOLeTNIK W7-x.Team Institute for energy-and Climate research/Plasma Physics Forschungszentrum Jülich GmbH52425 JülichGermany Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China Max.Planck Institut für Plasmaphysik 17491 GreifswaldGermany Wigner research Centre for Physics 1525 BudapestHungary Max.Planck Institut für Plasmaphysik 85748 GarchingGermany 不详

The W7-x.stellarator is optimized with respect to neoclassical *** turbulent transport plays an important *** is equipped with an inertial cooled graphite divertor which intersects the island chain at the plasma edge depending on the magnetic *** control coils and the plasma current modify the iota profile at the plasma edge and shift the position of the island *** monitor the effects on the poloidal propagation velocity in the scrape-off layer(SOL)and the plasma edge,an O-mode Poloidal Correlation reflectometer(PCr)is used which simultaneously monitors the propagation of low-k *** in the density range of 0.6?×?1019 m-3 to2?×?1019 m-3 it covers a large part of the SOL and the plasma edge and allows for the ex.erimental determination in the last closed flux.surface(LCFS)and the associated shear layer in low to middensity *** this paper it is shown that the propagation in the shear layer and its vicinity is determined best,when based on an elliptical *** magnetic configurations with magnetic edge topology of five independent islands forι?=?1 and six.linked islands forι?=?0.81 are *** the effects of the plasma current and additional control coils on the edge magnetic topology are *** coherence spectra of antenna pairs for different poloidal separations is *** a decomposition method for the measured coherence spectra the characterization of turbulence spectra is possible with respect to *** band turbulence and quasi coherent modes.A strong reduction of the broad band turbulence is observed in the vicinity of the LCFS which is evidence for the suppression of low-k turbulence at the shear layer.

关键词： stellarator correlation reflectometer turbulence rotation scrape-off layer island divertor

Design and Synthesis of Photoaffinity Probe Candidates for the GABA-gated Chloride Channel

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Chinese Journal of Chemistry 2006年第10期24卷 1435-1438页

作者：刘尚钟 LI Qing-x. Department of Applied Chemistry China Agricultural University Beijing 100094 China Department of Molecular Biosciences and Bioengineering University of Hawaii at Manoa Honolulu Hawaii 96822 USA

In order to characterize binding sites of insecticidal compounds on GABA gated chloride channel, new photoaffinity probe candidates based on 5e-t-butyl-2e-[4-（substituted-propynyl）phenyl]-1,3-dithiane for the noncompetitive blocker （NCB） site of the γ-aminobutyric acid （GABA）-gated chloride channel were designed and synthesized, and their potency as an inhibitor on NCB was measured by 4＇-ethynyl-4-n-[2,3-^3H2]-propylbicycloorthobenzoate （^3H eBOB） assay. The synthesized compounds showed high inhibition activities with half max.mum inhibition concentrations （IC50） of lower than 35 nmol/L and were very stable in binding conditions as well photoreacted quickly at 300 nm light. These new compounds are ex.ected to be good photoaffinity labeling probes if radioisotope iodine is incorporated.

关键词： photoaffinity labeling GABA receptor 1,3-dithiane

Crack patterns corresponding to the residual strength plateau of ceramics subjected to thermal shock

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Acta Mechanica Sinica 2012年第3期28卷 670-674页

作者： H.-L.Hou x.-e Wu P.Yan F.Song J.Li C.-P.Jiang School of Aeronautic Science and engineering B eihang University100191 BeijingChina State Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of Sciences100190 BeijingChina LSPM CNRS UPR 3407Universite Paris XIII99 Avenue Jean-Baptiste Clement93430 VilletaneuseFrance

The formation strength plateau of ceramics is addressed. A set of of 99A1203 are conducted, mechanism of the residual subjected to thermal shock thermal shock ex.eriments where the thin specimens of 1 mm× 10 mm×50 mm ex.ibit parallel through edge cracks, and thus permit quantitative measurements of the crack patterns. The cracks evolve with the severity of ther- mal shock. It is found that there is a correlation between the length and density of the thermal shock cracks. The increase of crack length weakens the residual strength, whereas the increase of crack density improves it. In a considerably wide temperature range, the two contrary effects just counteract each other; consequently a plateau appears in the variation curve of the residual strength. A comparison between the numerical and ex.erimental results of the residual strength is made, and they are found in good agreement. This work is helpful to a deep understanding of the thermal shock failure of ceramics.

关键词： Ceramics Thermal shock Crack patterns residual strength - Stress intensity factor