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Deuterium retention in chemically vapor deposited tungsten carbide coatings and hot-rolled tungsten exposed to low-energy deuterium plasma

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Tungsten 2022年第1期4卷 10-19页

作者： Vladimir Kh.Alimov Joachim Roth Frumkin institute of Physical Chemistry and Electrochemistry Russian Academy of SciencesMoscow 119071Russia max-planck-Institut fur plasmaphysik 85748 GarchingGermany

Samples of chemically vapor deposited(CVD)coatings of tungsten carbides W_(45)C_(55)and W_(60)C_(40)and samples of hot-rolled tungsten were exposed to deuterium(D)plasma at sample temperatures ranging from 323 to 813 K,as a result of which the samples were irradiated with D ions with an energy of about 200 eV per D particle at a flux of D particles of about1.1×10^(21)D·m^(-2)·s^(-1)to a fluence of about 2×10^(24)D·m^(-2).The concentration of deuterium in these samples was examined by the D(3 He,p)4 He nuclear *** on the measured deuterium depth profiles and assuming that these profiles are determined by diffusing D atoms,the diffusion coefficients of deuterium in the CVD tungsten carbide coatings were *** these diffusion coefficients,an estimate of the Arrhenius relation for the diffusion coefficients of deuterium in CVD tungsten carbide coatings was obtained:D=2.5×10^(-3)exp(-1.12 eV/kT)m~2·s^(-1),where T is temperature expressed in Kelvin,and k is the Boltzmann *** concentration of trapped deuterium in the bulk of CVD tungsten carbide coatings is practically independent of the stoichiometry of the *** decreases from about 5×10^(-2)to about 7×10^(-4)D/(W+C)with an increase in the deuterium plasma exposure temperature from 373 to 813 *** concentration of trapped deuterium in hot-rolled tungsten,expressed in units of the D/W atomic ratio,is more than an order of magnitude lower than the concentration of deuterium in tungsten carbides,and also decreases with increasing plasma exposure temperature.

关键词： Chemically vapor deposited tungsten carbides Tungsten Deuterium plasma Deuterium depth profiles Deuterium diffusion coefficients

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Relationship Between Oct agonal Quasicrystal and β-Mn Type Crystal in Cut Description

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Chinese Physics Letters 1996年第3期13卷 199-202页

作者： LI Fang-hua CHENG Yi-fan institute of Physics Chinese Academy of SciencesBeijing 1000801 max-planck-Institut fur Metallforschung Institut fur Werkstoff-WeissenschaftSeestrasse 9270147 StuttgartGermany

The transformation from the octagonal lattice to a square lattice is demonstrated straightforward under the cut description by introducing a peculiar linear phason *** calculated lattice parameter of the ft-Mn structure from the edge length of squares and rhombi forming the octagonal quasilattice is in agreement with experimental results.

关键词： strain. agonal lattice

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A Coupled Model Study on the Intensification of the Asian Summer Monsoon in IPCC SRES Scenarios

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Advances in Atmospheric Sciences 2005年第6期22卷 798-806页

作者： Min WEI max-planck-Institut fur Meteorologie Bundesstrasse 53 D-20146 Hamburg Germany

The Asian summer monsoon is an important part of the climate system. Investigating the response of the Asian summer monsoon to changing concentrations of greenhouse gases and aerosols will be meaningful to understand and predict climate variability and climate change not only in Asia but also globally. In order to diagnose the impacts of future anthropogenic emissions on monsoon climates, a coupled general circulation model of the atmosphere and the ocean has been used at the max-planck-institute for Meteorology. In addition to carbon dioxide, the major well mixed greenhouse gases such as methane, nitrous oxide, several chlorofluorocarbons, and CFC substitute gases are prescribed as a function of time. The sulfur cycle is simulated interactively, and both the direct aerosol effect and the indirect cloud albedo effect are considered. furthermore, changes in tropospheric ozone have been pre-calculated with a chemical transport model and prescribed as a function of time and space in the climate simulations. Concentrations of greenhouse gases and anthropogenic emissions of sulfur dioxide are prescribed according to observations （1860-1990） and projected into the future （1990-2100） according to the Scenarios A2 and B2 in Special Report on Emissions Scenarios （SRES, Nakcenovic et al., 2000） developed by the Intergovernmental Panel on Climate Change （IPCC）. It is found that the Indian summer monsoon is enhanced in the scenarios in terms of both mean precipitation and interannual variability. An increase in precipitation is simulated for northern China but a decrease for the southern part. furthermore, the simulated future increase in monsoon variability seems to be linked to enhanced ENSO variability towards the end of the scenario integrations.

关键词： asian summer monsoon climate change IPCC SRES scenarios

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Tests of gravitational symmetries with radio pulsars

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Science China(Physics,Mechanics & Astronomy) 2016年第9期59卷 10-32页

作者： LiJing Shao Norbert Wex max planck institute for Gravitational Physics (Albert Einstein institute) Potsdam-Golm D-14476 Germany School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China max-planck-Institut fur Radioastronomie Bonn D-53121 Germany

Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies,time-shift symmetry in the gravitational constant, local position invariance and local Lorentz invariance of gravity, and spacetime translational symmetries. Recent experimental explorations for post-Newtonian gravity are discussed, of which, those from pulsar astronomy are highlighted. All of these tests, of very different aspects of gravity theories, at very different length scales, favor to very high precision the predictions of the strong equivalence principle(SEP) and, in particular, general relativity which embodies SEP completely. As the founding principles of gravity, these symmetries are motivated to be promoted to even stricter tests in future.

关键词： gravitation radio pulsars spacetime symmetry

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Characteristics in naturally and experimentally shocked chondrites: A clue to P-T conditions of impacted asteroids

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Science China Earth Sciences 2000年第5期43卷 480-486页

作者：谢先德陈鸣戴诚达 A.EI Goresy Guangzhou institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China max-planck-institute fur Chemie Mainz 55128 Germany

The aim of this study is to compare the experimentally shock-induced features with those in naturally shocked chondrites and to test the feasibility of experimentally calibrating naturally induced features in shocked H- and L-chondrites. Samples of the Jilin chondrite (H5) were experimentally shock-loaded at the following peak pressures: 12, 27, 39, 53, 78, 83, 93 and 133 GPa respectively. Chondritic melts were first obtained at P>78 GPa and more than 60% melting was achieved at P^133 GPa. No high-pressure phases were observed in any of the shocked samples, neither in the deformed nor in the molten regions. Textural relations and mineral assemblages of the shocked samples are comparable to those encountered in the heavily shocked H-chondrite Yanzhuang but differ considerably from those found in heavily shocked L6 chondrites. Shock melt veins in L6 chondrites contain high-pressure polymorphs of olivine and pyroxene and high pressure liquidus phases. Scaling from shock experiments on millimeter-sized samples to natural shock features on kilometer-sized asteroids poses considerable problems in quantifying the P-T conditions during natural shock events on asteroids.

关键词： chondrite experiment shock characteristics asteroid P-T condition.

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Magnetic configuration effects on the edge heat flux in the limiter plasma on W7-X measured using the infrared camera and the combined probe

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Plasma Science and Technology 2018年第5期20卷 18-22页

作者： P DREWS H NIEMANN J COSFELD Y GAO J GEIGER O GRULKE M HENKEL D HOSCHEN K HOLLFELD C KILLER A KRAMER-FLECKEN Y LIANG S LIU D NICOLAI O NEUBAUER M RACK B SCHWEER G SATHEESWARAN L RUDISCHHAUSER N SANDRI N WANG the W7-X Team Forschungszentrum Jtilich GmbH Institut fur Energie-und Klimaforschung PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)D-52425 JulichGermany max-planck-Institut fur plasmaphysik GreifswaldGermany Forschungszentrum Jtilich GmbH Central Institute for EngineeringElectronics and Analytics/Engineering and Technology(ZEA-1)D-52425 JulichGermany JARA-HPC Germany School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhan 430074People's Republic of China

Controlling the heat and particle fluxes in the plasma edge and on the plasma facing components is important for the safe and effective operation of every magnetically confined fusion *** was attempted on Wendelstein 7-X in the first operational campaign,with the modification of the magnetic configuration by use of the trim coils and tuning the field coil currents,commonly named iota ***,the heat loads on the five limiters are ***,they differ between each limiter and are non-uniform,due to the（relatively small） error fields caused by the misalignment of *** is therefore necessary to study the influence of the configuration changes on the transport of heat and particles in the plasma edge caused by the application of error fields and the change of the magnetic *** this paper the upstream measurements conducted with the combined probe are compared to the downstream measurements with the DIAS infrared camera on the limiter.

关键词： Wendelstein 7-X W7-X plasma edge heat flux limiter

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On the character of certain tilting modules

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Science China Mathematics 2018年第2期61卷 295-298页

作者： George Lusztig Geordie Williamson Department of Mathematics Massachusetts Institute of Technology Cambridge MA 02139-4307 USA max planck Institut fur Mathematik Bonn 53111 Germany

Let G be a semisimple group over an algebraically closed field of characteristic p > 0. We give a(partly conjectural) closed formula for the character of many indecomposable tilting rational G-modules assuming that p ... 详细信息

关键词： semisimple group tilting module character formula

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Search for H I emission from superdisk candidates associated with radio galaxies

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Research in Astronomy and Astrophysics 2019年第6期19卷 71-78页

作者： Abhijeet Anand Nirupam Roy Gopal-Krishna max-planck-Institut fur Astrophysik Karl-Schwarzschild-Str. 1 D-85741 Garching Germany Department of Physics Indian Institute of Science Bangalore - 560012 India Aryabhatta Research institute of Observational Sciences (ARIES) Manora Peak Nainital - 263129 India max-planck-Institut fur Radioastronomie Auf dem Hugel 69 53121 Bonn Germany

Giant gaseous layers(termed “superdisks”) have been hypothesized in the past to account for the strip-like radio emission gap(or straight-edged central brightness depression) observed between twin radio lobes, in over a dozen relatively nearby powerful Fanaroff-Riley Class II radio galaxies. They could also provide a plausible alternative explanation for a range of observations. Although a number of explanations have been proposed for the origin of the superdisks, little is known about their material content. Some X-ray observations of superdisk candidates indicate the presence of hot gas, but a cool dusty medium also seems to be common. If they are entirely or partly composed of neutral gas, then it may be directly detectable and we report here a first attempt to detect/image any neutral hydrogen gas present in the superdisks that are inferred to be present in four nearby radio galaxies. We have not found a positive H I signal in any of the four sources, resulting in tight upper limits on the H I number density in the postulated superdisks,estimated directly from the central rms noise values of the final radio continuum subtracted image. The estimated ranges of the upper limit on neutral hydrogen number density and column density are 10^-4-10^-3 atoms per cm3 and 10^19-10^20 atoms per cm^2, respectively. No positive H I signal is detected even after combining all the four available H I images(with inverse variance weighting). This clearly rules out an H I dominated superdisk as a viable model to explain these structures, however, the possibility of a superdisk being composed of warm/hot gas still remains open.

关键词： galaxies:active galaxies:general galaxies:structure radio lines:galaxies

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THE CHEMICAL COMPOSITIONS OF MINERALS IN QINGZHEN METEORITE AND ITS GEOCHEMISTRY SIGNIFICANCE

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Science China Chemistry 1989年第8期32卷 995-1002页

作者：侯渭欧阳自远 A.EL.GORESY H.YABUKI Guiyang institute of Geochemistry Academia Sinica max-planck institute fur Kernphysik Heidelberg West Germany institute of Physical and Chemical Research Japan

The chemical compositions of silicate minerals, sulphide minerals and metal Fe-Ni in theQingzhen meteorite were measured by the microprobe analyses. Based upon these chemicalcompositions, the cosmochemical behaviour and characteristics of the existing forms of themajor elements in the Qinzhen meteorite have been discussed. These characteristics show thatunder the S-rich, O-poor, and strongly reducing conditions, the light metal elements, such asCa, Mg, K, Na may form sulphide, and metal Fe-Ni may contain Si and P. However, we con-sider that the light metal-sulphide can be stable in the lower mantle and there are some Siand P in the Fe-Ni core. Finally, an earth core-mantle model is established, where the Fe-Ni core contains some Si and P; the lower mantle is composed of Mg-rich silicate, SiO_2 andsulphide; the upper mantle, of silicate and oxide.

关键词： enstatite chondrite Qingzhen meteorite earth core-mantle model

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Overview of the J-TEXT progress on RMP and disruption physics

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Plasma Science and Technology 2018年第12期20卷 19-30页

作者： Yonghua DING Zhongyong CHEN Zhipeng CHEN Zhoujun YANG Nengchao WANG Qiming HU Bo RAO Jie CHEN Zhifeng CHENG Li GAO Zhonghe JIANG Lu WANG Zhijiang WANG Xiaoqing ZHANG Wei ZHENG Ming ZHANG Ge ZHUANG Qingquan YU Yunfeng LIANG Kexun YU Xiwei HU Yuan PAN Kenneth William GENTLE International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People＇s Republic of China max-planck-Institut fur plasmaphysik 85748 GarchingGermany Forschungszentrum Julich GmbH Institut fur Energie-und Klimaforschung-Plasmaphysik52425 JulichGermany institute of Plasma Physics Chinese Academy of SciencesHefei 230031People＇s Republic of China institute for Fusion Studies University of Texas at AustinAustinTX 78712United States of America

The J-TEXT tokamak has been operated for ten years since its first plasma obtained at the end of 2007. The diagnostics development and main modulation systems, i.e. resonant magnetic perturbation （RMP） systems and massive gas injection （MGI） systems, will be introduced in this paper. Supported by these efforts, J-TEXT has contributed to research on several topics, especially on RMP physics and disruption mitigation. Both experimental and theoretical research show that RMP could lock, suppress or excite the tearing modes, depending on the RMP amplitude, frequency difference between RMP and rational surface rotation, and initial stabilities. The plasma rotation, particle transport and operation region are influenced by the RMP. Utilizing the MGI valves, disruptions have been mitigated with pure He, pure Ne, and a mixture of He and Ar （9：1）. A significant runaway current plateau could be generated with moderate amounts of Ar injection. The RMP has been shown to suppress the generation of runaway current during disruptions.

关键词： resonant magnetic perturbation (RMP) massive gas injection (MGI) runaway current disruption J-TEXT

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