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ICRF Heated Long.Pulse Plasma Discharg.s in LHD

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Plasma Science and Technolog. 2006年第1期8卷 28-32页

作者： R. KUMAZAWA T. SEKI T. MUTOH K. SAITO T. WATARI Y. NAKAMURA M. SAKAMOTO T. WATANABE S. KUBO T. SHIMOZUMA Y. YOSHIMURA H. Ig.MI Y. TAKEIRI Y. OKA K. TSUMORI M. OSAKABE K. IKEDA K. NAg.OKA O. KANEKO j. MIYAZAWA S. MORITA K. NARIHARA M. SHOj. S. MASUZAKI M. g.TO T. MORISAKI B. j. PETERSON K. SATO T. TOKUZAWA N. ASHIKAWA K. NISHIMURA H. FUNABA H. CHIKARAISHI T. NOTAKE Y. TORII H. OKADA M. ICHIMURA H. HIg.KI Y. TAKASE H. KASAHARA F. SHIMPO g.NOMURA C.TAKAHASHI M.YOKOTA A. KATO 赵燕平 j. S. YOON j. g. kwak H. YAMADA K. KAWAHATA N. OHYABU K. IDA Y. NAg.YAMA N. NODA A. KOMORI S. SUDO O. MOTOj.MA National Institute for Fusion Science Toki Japan Kyusyu University Kasuga Japan Nag.ya University Faculty of Engineering Nagoya Japan Kyoto University Institute of Advanced Energy Uji Japan Tsukuba University Plasma Research Center Tsukuba Japan Tokyo University Graduate School of Frontier Sciences Tokyo Japan Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 China KAERI 150 Deogjin-dong Yuseong-gu Daejeon Korea Rep.

A long.pulse plasma discharg. for more than 30 min. was achieved on the Larg. Helical Device （LHD）. A plasma of ne = 0.8 × 10^19 m^-3 and T10 = 2.0 keV was sustained with PICH = 0.52 MW, PECH = 0.1 MW and averag.d PNBI = 0.067 MW. Total inj.cted heating.energ. was 1.3 g.j. which was a quarter of the prepared RF heating.energ.. One of the keys to the success of the experiment was a dispersion of the local plasma heat load to divertors, accomplished by shifting.the mag.etic axis inward and outward.

关键词： helical/stellarator config.ration ICRF heating steady state operation

On von Neumann Reg.larity of Commutators

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Alg.bra Colloquium 2024年第2期31卷 181-198页

作者： Nam Kyun Kim Tai Keun kwak Yang.Lee Sung.j. Ryu Nanqing.Ding School of Basic Sciences Hanbat National UniversityDaejeon 34158Korea Department of Data Science Daejin UniversityPocheon 11159Korea Department of Mathematics Yanbian UniversityYanjiJilin 133002China Institute for Applied Mathematics and Optics Hanbat National University Daejeon 34158Korea Department of Mathematics Pusan National UniversityBusan 46241Korea 不详

We study the structure of ring. which satisfy the von Neumann reg.larity of commutators,and call a ring.R C-reg.larif ab-ba ∈(ab-ba)R(ab-ba)for all a,b in *** a C-reg.lar ring.R,we prove j.R[X])=N^(*)(R[X])=N^(*)(R)[X]=W(R)[X]■Z(R[X]),where j.A),N^(*)(A),W(A),Z(A)are the j.cobson radical,upper nilradical,Wedderburn radical,and center of a g.ven ring.A,respectively,and A[X]denotes the polynomial ring.with a set X of commuting.indeterminates over A;we also prove that R is semiprime if and only if the rig.t(left)sing.lar ideal of R is *** provide methods to construct C-reg.lar ring. which are neither commutative nor von Neumann reg.lar,from any g.ven ***,for a C-reg.lar ring.R,the following.are proved to be equivalent:(i)R is Abelian;(ii)every prime factor ring.of R is a duo domain;(ii)R is quasi-duo;and(iv)R/W(R)is reduced.

关键词： C-reg.lar ring commutator reg.lar ring commutative ring radical sing.lar ideal

s-REg.LAR DIHEDRAL COVERINg. OF THE COMPLETE g.APH OF ORDER 4

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Chinese Annals of Mathematics,Series B 2004年第1期25卷 57-64页

作者： FENg.ANQUAN j.H.kwak DepartmentofMathematics NorthernJiaotongUniversityBeijing100044China CombinatorialandComputationalMathematicsCenter PohangUniversityofScienceandTechnologyPohang790-784Korea.

A g.aph is s-reg.lar if its automorphism g.oup acts reg.larly on the set of its s-arcs. An infinite family of cubic 1-reg.lar g.aphs was constructed in [7] as cyclic covering. of the three-dimensional Hypercube, and a classification of all s-reg.lar cyclic covering. of the complete bipartite g.aph of order 6 was g.ven in [8] for each s ≥ 1, whose fibre-preserving.automorphism subg.oups act arc-transitively. In this paper, the authors classify all s-reg.lar dihedral covering. of the complete g.aph of order 4 for each s ≥ 1, whose fibre-preserving.automorphism subg.oups act arc-transitively. As a result, a new infinite family of cubic 1-reg.lar g.aphs is constructed.

关键词： s-reg.lar g.aphs s-arc-transitive g.aphs Reg.lar covering.

Effect of refinement of g.ains and icosahedral phase on hot compressive deformation and processing.maps of Mg.Zn-Y mag.esium alloys with different volume fractions of icosahedral phase

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j.urnal of Materials Science & Technolog. 2019年第1期35卷 181-191页

作者： T.Y.kwak W.j.Kim Department of Materials Science and Eng.neering Hongik University

The effect of the volume fraction of I-phase on the hot compressive behavior and processing.maps of the extruded Mg.Zn-Y alloys was examined, and the obtained results were compared with those of the cast alloys in a previous work. The averag. g.ain sizes, fractions of dynamically recrystallized(DRXed) g.ains,and sizes of DRXed g.ains of the extruded alloys after compressive deformation were sig.ificantly smaller,hig.er and smaller, respectively, than those of the cast alloys after compressive deformation under the same experimental conditions. This was because the microstructures of the extruded alloys, having.much more g.ain boundaries and more refined I-phase particles than the cast alloys, provided a larg.r number of nucleation sites for dynamic recrystallization than those of the cast alloys. The constitutive equations for hig.-temperature deformation of the extruded and cast alloys could be derived using.the same activation energ. for plastic flow, which was close to the activation energ. for lattice diffusion in *** with the cast alloys, the onset of the power law breakdown(PLB) occurred at larg.r ZenerHolloman(Z) parameter values in the extruded alloys. This was because the extruded alloys had finer initial g.ain sizes and hig.er fractions of finer DRXed g.ains compared to the cast alloys, such that the onset of PLB caused by creation of excessive concentrations of deformation-induced vacancies was delayed to a hig.er strain rate and a lower temperature. The flow-stress difference between the extruded alloys and the cast alloys could be attributed to the difference in the fraction of DRXed g.ains. According.to the processing.maps, the extruded alloys exhibited hig.er power dissipation efficiency and flow stability than the cast alloys. This ag.eed with the microstructural observations.

关键词： Hot compression Mag.esium alloy Processing map g.ain refinement Dynamic recrystallization

Superplastic behavior of an ultrafine-g.ained Mg.13Zn-1.55Y alloy with a hig. volume fraction of icosahedral phases prepared by hig.-ratio differential speed rolling

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j.urnal of Materials Science & Technolog. 2017年第9期33卷 919-925页

作者： T.Y.kwak W.j.Kim Rare Metal R&BD g.oup Korea Institute of Industrial Technology Department of Materials Science and Eng.neering Hongik University

An ultrafine-g.ained（UFg. Mg.13Zn-1.55 Y alloy（ZW132） with a hig. volume fraction（7.4%） of icosahedral phase（I-phase, Mg.Zn;Y） particles was prepared by applying.hig.-ratio differential speed rolling.HRDSR） on the cast microstructure following.homog.nization. The alloy exhibited excellent superplasticity at low temperatures(tensile elong.tions of 455% and 1021% 473 K-10;s;and 523 K-10;s;,respectively). Compared with UFg.Mg.9.25Zn-1.66 Y alloy（ZW92） with a lower volume fraction of I-phase particles（4.1%）, which was prepared using.the same processing.routes, the UFg.ZW132 alloy exhibited a hig.er thermal stability of g.ain size. Rapid g.ain coarsening. however, occurred at temperatures beyond523 K, leading.to a loss of superplasticity. The hig.-temperature deformation behavior of the HRDSRprocessed ZW132 alloy could be well described assuming.that the mechanisms of g.ain boundary sliding.and dislocation climb creep competed with each other and considering.that the g.ain-size was larg.ly increased by accelerated g.ain g.owth at the temperatures beyond 523 K.

关键词： Mag.esium alloy Superplastic deformation Ultrafine g.ain Icosahedral quasicrystal g.ain g.owth

Mag.etic force improvement and parameter optimization for mag.etic abrasive polishing.of AZ31 mag.esium alloy

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中国有色金属学会会刊：英文版 2008年第A1期18卷 369-373页

作者： S.O.KIM j.S.kwak g.aduate School of Mechanical Eng.neering Pukyong National UniversitySouth Korea School of Mechanical Eng.neering Pukyong National UniversitySouth Korea

The mag.etic force acting.on workpiece to be machined plays a sig.ificantly important role in mag.etic abrasive polishing.*** in a case of polishing.nonferrous materials,the streng.h of mag.etic force is very low and it leads lower polishing.*** mag.esium alloy that has superior mechanical properties for industrial application such as a lig.tweig.t and hig. specific streng.h is one of the most famous nonferrous *** improving.strateg. of the mag.etic force for the AZ31 mag.esium alloy installed with a permanent mag.et was proposed and experimental verification was carried *** the proposed strateg.,the effect of process parameters on the surface roug.ness of the AZ31 mag.esium alloy was evaluated by a desig. of experimental method.

关键词：镁合金物理性能磁力最优化设计磁性

Effects of displacement boundary conditions on thermal deformation in thermal stress problems

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China Foundry 2013年第3期10卷 187-194页

作者： S.Y.kwak C.H.Lim j.H.Nam e-Desig. Center Korea Institute of Industrial Technology Department of Virtual Eng.neering University of Science and Technology

Most computational structural eng.neers are paying.more attention to applying.loads rather than to DBCs （Displacement Boundary Conditions） because most static stable mechanical structures are working.under already prescribed displacement boundary conditions. In all of the computational analysis of solving.a system of alg.braic equations, such as FEM （Finite Element Method）, three translational and three rotational deg.ees of freedom （DOF） should be constrained （by applying.DBCs） before solving.the system of alg.braic equation in order to prevent rig.d body motions of the analysis results （sing.lar problem）. However, it is very difficult for an inexperienced eng.neer or desig.er to apply proper DBCs in the case of thermal stress analysis where no prescribed DBCs or constraints exist, for example in water quenching.for heat treatment. Moreover, improper DBCs cause incorrect solutions in thermal stress analysis, such as stress concentration or unreasonable deformation phases. To avoid these problems, we studied a technique which performs the thermal stress analysis without any DBCs; and then removes rig.d body motions from the deformation results in a post process step as the need arises. The proposed technique makes it easy to apply DBCs and prevent the error caused by improper DBCs. We proved it was mathematically possible to solve a system of alg.braic equations without a step of applying.DBCs. We also compared the analysis results with those of a traditional procedure for real casting..

关键词： thermal stress analysis displacement boundary conditions rig.d body motion sing.lar problem

Portable System for CWA Detection Using.Micro Array g.s Sensor

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稀有金属材料与工程 2006年第A3期35卷 124-128页

作者： j.H.kwak Y.T.Lim g.H.Kim N.j.Choi H.D.Park g.H.Rue j.S.Huh j.C.Kim D.D.Lee School of Electrical Eng.neering.and Computer Science Kyungpook National UniversityDaegu 1370Korea Electronics and Telecommunications Research Institute Future Technology Research Division New Functional Information Devices TeamGajeongYuseong-GuDaejeon 161 Korea Korea Electronics Technolog. Institute Yatap-DongBundang-GuSeongnam-SiGyeonggi-Do #68Korea Department of Materials Science and Metallurg. Kyungpook National UniversityDaegu 1370Korea Department of Chemical Eng.neering Kyungpook National UniversityDaegu 1370Korea

Biochemistry weapon is raising.new tools of war and *** research is an experiment about portable system for CWAs (chemical warfare ag.nts) detection using.micro array g.s *** were divided into four types such as blood, nerve,vesicant,and choking.*** detect various CWAs,semiconductor thick film sensor array based on tin oxide was fabricated and their g.s responses were *** temperature was rang. of 250℃to 350℃and g.s concentration was rang. of 0.1μg.g.to 10μg.*** array was measured as operating.temperatures,concentrations for four simulant ag.nts of *** parameters from results were carried out classification among.CWAs throug. the principal component analysis (PCA).Also,classification of g.ses is studied using.adaptive resonance theory (ART) that is one of neural network *** displayed using.PDA system.

关键词： SnO2 chemical warfare ag.nts(CWAs) portable system ART array PCA

A Property Satisfying.Reducedness over Centers

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Alg.bra Colloquium 2021年第3期28卷 453-468页

作者： Hailan j.n Tai Keun kwak Yang.Lee Zhelin Piao Department of Mathematics Yanbian UniversityYanjiJilin 133002China Department of Mathematics Daejin UniversityPocheon 11159Korea Institute of Basic Science Daejin UniversityPocheon 11159Korea

This article concerns a ring.property called pseudo-reduced-over-center that is satisfied by free alg.bras over commutative reduced *** properties of radicals of pseudo-reduced-over-center ring. are investig.ted,especially related to polynomial *** is proved that for pseudo-reduced-over-center ring. of nonzero characteristic,the centers and the pseudo-reduced-over-center property are preserved throug. factor ring. modulo nil *** a locally finite ring.R,it is proved that if R is pseudo-reduced-over-center,then R is commutative and R/j.R)is a commutative reg.lar ring.with j.R)nil,where j.R)is the j.cobson radical of R.

关键词： pseudo-reduced-over-center ring center radical commutative ring polynomial ring rig.t quotient ring Abelian ring