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Magnetic wallpaper Dirac fermions and topological magnetic Dirac insulators

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npj Computational Materials 2023年第1期9卷 1695-1702页

作者： Yoonseok Hwang Yuting Qian Junha Kang Jehyun Lee Dongchoon Ryu Hong Chul Choi bohm-Jung Yang Center for Correlated Electron Systems Institute for Basic Science(IBS)Seoul 08826Korea Department of Physics and Astronomy Seoul National UniversitySeoul 08826Korea Center for Theoretical Physics(CTP) Seoul National UniversitySeoul 08826Korea

Topological crystalline insulators(TCIs)can host anomalous surface states which inherits the characteristics of crystalline symmetry that protects the bulk ***,the diversity of magnetic crystalline symmetries indicates the potential for novel magnetic TCIs with distinct surface ***,we propose a topological magnetic Dirac insulator(TMDI),whose two-dimensional surface hosts fourfold-degenerate Dirac fermions protected by either the p'_(c)4mm or p40 g0 m magnetic wallpaper *** bulk topology of TMDIs is protected by diagonal mirror symmetries,which give chiral dispersion of surface Dirac fermions and mirror-protected hinge *** propose candidate materials for TMDIs including Nd_(4)Te_(8)Cl_(4)O_(2)0 and DyB_(4) based on first-principles calculations,and construct a general scheme for searching TMDIs using the space group of paramagnetic parent *** theoretical discovery of TMDIs will facilitate future research on magnetic TCIs and illustrate a distinct way to achieve anomalous surface states in magnetic crystals.

关键词： Dirac topological protected

Stiefel–Whitney classes and topological phases in band theory

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Chinese Physics B 2019年第11期28卷 1-17页

作者： Junyeong Ahn Sungjoon Park Dongwook Kim Youngkuk Kim bohm-Jung Yang Department of Physics and Astronomy Seoul National UniversitySeoul 08826Korea Center for Correlated Electron Systems Institute for Basic Science(IBS)Seoul 08826Korea Center for Theoretical Physics(CTP) Seoul National UniversitySeoul 08826Korea

We review the recent progress in the study of topological phases in systems with space–time inversion symmetry *** an anti-unitary symmetry which is local in momentum space and satisfies I2 ST= 1 such as PT in two dimensions(2 D)and three dimensions(3 D) without spin–orbit coupling and C2 T in 2 D with or without spin–orbit coupling, where P, T, C2 indicate the inversion, time-reversal, and two-fold rotation symmetries, respectively. Under IST, the Hamiltonian and the periodic part of the Bloch wave function can be constrained to be real-valued, which makes the Berry curvature and the Chern number vanish. In this class of systems, gapped band structures of real wave functions can be topologically distinguished by the Stiefel–Whitney numbers instead. The first and second Stiefel–Whitney numbers w1 and w2, respectively,are the corresponding invariants in 1 D and 2 D, which are equivalent to the quantized Berry phase and the Z2 monopole charge, respectively. We first describe the topological phases characterized by the first Stiefel–Whitney number, including1 D topological insulators with quantized charge polarization, 2 D Dirac semimetals, and 3 D nodal line semimetals. Next we review how the second Stiefel–Whitney class characterizes the 3 D nodal line semimetals carrying a Z2 monopole *** particular, we explain how the second Stiefel–Whitney number w2, the Z2 monopole charge, and the linking number between nodal lines are related. Finally, we review the properties of 2 D and 3 D topological insulators characterized by the nontrivial second Stiefel Whitney class.

关键词： topological semimetal

Interface evolution of TiAl/Ti6242 transient liquid phase joint using Ti, Cu foils as insert metals

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中国有色金属学会会刊：英文版 2005年第2期15卷 375-378页

作者：段辉平 K.H.bohm V.Ventzke M.Koak School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China Institute for Materials Research GKSS Research Center Geesthacht Geesthacht D-21502 Germany

The interface evolution of TiAl/Ti6242 joint produced by transient liquid phase(TLP) bonding with Ti, Cu foils as insert metals was investigated. The results show that the surface oxide layer on TiAl plays a very important role in the formation process of the joint. A ‘bridge’ effect is observed because of the presence of the oxide layer on the surface of TiAl. The diffusion behavior of Cu atoms in TiAl is strongly controlled by the vacancies beneath the surface of TiAl. Based on the interface diffusion and interface wettability, a mechanism for the effect of bonding pressure, bonding temperature, holding time and stacking sequence of the insert foils on the joint formation process were proposed.

关键词：铝钛合金瞬态液相压焊表面蒸气机械性能

Highly efficient passive Tesla valves for microfluidic applications

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Microsystems & Nanoengineering 2022年第5期8卷 125-136页

作者： Sebastian bohm Hai Binh Phi Ayaka Moriyama Erich Runge Steffen Strehle Jörg König Christian Cierpka Lars Dittrich Theoretical Physics I Technische Universität IlmenauWeimarer Straße 2598693 IlmenauGermany Research and Development 5microns GmbHMargarethenstraße 698693 IlmenauGermany Institute of Micro-and Nanotechnologies Gustav-Kirchhoff-Straße 798693 IlmenauGermany Microsystems Engineering Technische Universität IlmenauMax-Planck-Ring 1298693 IlmenauGermany Physics and Astronomy Carleton CollegeOne North CollegeNorthfield 55057 MinnesotaUSA Engineering Thermodynamics Technische Universität IlmenauAm Helmholtzring 198693 IlmenauGermany

A multistage optimization method is developed yielding Tesla valves that are efficient even at low flow rates,characteristic,e.g.,for almost all microfluidic systems,where passive valves have intrinsic advantages over active *** report on optimized structures that show a diodicity of up to 1.8 already at flow rates of 20μl s^(−1) corresponding to a Reynolds number of *** of the design is a topological optimization based on the finite element *** is set-up to yield easy-to-fabricate valve structures with a small footprint that can be directly used in microfluidic *** numerical two-dimensional optimization takes into account the finite height of the channel approximately by means of a so-called shallow-channel *** on the threedimensionally extruded optimized designs,various test structures were fabricated using standard,widely available microsystem manufacturing *** manufacturing process is described in detail since it can be used for the production of similar cost-effective microfluidic *** the experimentally fabricated chips,the efficiency of the different valve designs,i.e.,the diodicity defined as the ratio of the measured pressure drops in backward and forward flow directions,respectively,is measured and compared to theoretical predictions obtained from full 3D calculations of the Tesla *** agreement is *** addition to the direct measurement of the diodicities,the flow profiles in the fabricated test structures are determined using a two-dimensional microscopic particle image velocimetry(μPIV)***,a reasonable good agreement of the measured flow profiles with simulated predictions is observed.

关键词： backward Highly optimization

Diversity, Cohesion and the Development of the European Integration

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Economics World 2014年第6期2卷 395-408页

作者： Amost bohm Lenka Stibranyiova Technical University of Liberec Liberec Czech Republic

The European Union (EU) this year has entered into the next phase of its existence, not only in terms of new economic conditions of the unwinding of the financial and economic crisis, but also on the basis of the results of European Parliament elections and the adoption of the EU financial framework for the period from 2014 to 2020. These indisputable facts does not change our view of the situation in which the EU is, or at major tasks whose managing can be considered as condition of its continued existence as an important part of the global economy. As the fundamental problem of the EU, persisting differences in economic level of the member states is considered. The aim of this paper is not to formulate and even to propose how the EU should look like in the future, but to assess criteria of decision making about concept of its future direction. In this context, the verification of argument will be performed, that only the integration of the countries that have common interests and objectives respectively are able to make the same efforts to meet them, is in certain stages of integration possible and functional. Conversely, a broader territorial structured integration of countries with significantly different economic parameters is feasible and functional only at lower stages of integration. This paper starts from that the process of economic convergence among member states as a condition for integration can be realized at the lower stage of the integration process, in terms of economic and monetary union, then only the expense of reducing the dynamics of economic development of integration group as a whole. Some degree of equilibrium of economic levels represents an important condition for the success of the integration project. To meet this goal, current differences in economic level of individual EU member states (comparative analysis using indicators of growth rate and development of GDP/capita) will be analyzed, including the assessment of the cost of the EU fo

关键词：世界经济政策规划经济问题

The Crisis, Responsibility and Regulation

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Chinese Business Review 2012年第4期11卷 343-354页

作者： bohm Amost, Fujerova Irena Technical University ofLiberec Liberec Czech Republic

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Coin collecting

疯狂英语（新策略） 2019年第8期 58-59页

作者： Alan bohm 陆洪达不详

Coin collecting is one of the oldest hobbies and many people also like it in recent years,ifs become a very popular hobby for children of all *** fact,it's one of the best *** younger children,you can help them build ... 详细信息

关键词： Coin collecting oldest hobbies coin collection

Venus Flytrap HKT1-Type Channel Provides for Prey Sodium Uptake into Carnivorous Plant Without Conflicting with Electrical Excitability

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Molecular Plant 2016年第3期9卷 428-436页

作者： J. bohm S. Scherzer S. Shabala E. Krol E. Neher T.D. Mueller R. Hedrich Julius-yon-Sachs Institute Department for Molecular Plant Physiology and Biophysics University of Wurzburg Julius-von-Sachs Platz 2 97082 Wurzburg Germany School of Land and Food University of Tasmania Hobart TAS 7001 Australia Zoology Department College of Science King Saud University PO Box 2455 Riyadh 11451 Saudi Arabia Department for Membrane Biophysics Max Planck Institute for Biophysical Chemistry 37077 Goettingen Germany

The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na^＋- and K^＋-permeable mutants function as ion channels rather than K^＋ transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na^＋-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.

关键词： sodium channel HKT1 Dionaea muscipula action potential glands sodium uptake

Correction to“Asymmetrically hypointense veins on T2*w imaging and susceptibility-weighted imaging in ischemic stroke”[World J Radiol 2013;5(4):156-165]

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World Journal of Radiology 2018年第1期10卷 7-8页

作者： Ulf Jensen-Kondering Ruwen bohm Institute of Neuroradiology University of Schleswig-HolsteinCampus KielKiel 24105Germany Institute of Experimental and Clinical Pharmacology University of Schleswig-HolsteinCampus KielKiel 24105Germany

Correction to:Jensen-Kondering U,B?hm *** hypointense veins on T2*w imaging and susceptibility-weighted imaging in ischemic *** J Radiol 2013;5(4):156-165 PMID:23671751 DOI:10.4329/wjr.v5.i4.156[1].Results Third paragraph:(1)(n=17441 patients)should read(n=441 patients)instead;(2)(n=4111 patients)should read(n=111 patients)*** paragraph:(1)(>6 h,n=15579 patients)should read(>6 h,n=579 patients)instead;(2)(≤6 h=11337 patients)should read(≤6 h=337 patients)instead;(3)(170 patients)should read(180 patients)instead.

关键词： pat