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Ch.nese Ph.sics Letters 2006年第6期23卷 1422-1425页

作者： S. h. kim Department of Ph.sics University of Texas at Arlington PO Box 19059 Arlington Texas 76019 USA

We calculate th. scattering cross section of an electron with.respect to th. spontaneously produced laser radiation in th. first free-electron laser （FEL） with.quantum-wiggler electrodynamics （QWD）. Th. cross section is 1016 times th. Th.mson cross section, confirming th. result obtained by a previous analysis of th. experimental data. A QWD calculation sh.w th.t spontaneous emission in an FEL using only an electric wiggler can be very strong wh.le amplification th.ough.net stimulated emission is practically negligible.

关键词： CLASSICAL ELECTRODYNAMICS RELATIVISTIC ELECTRONS Th.RMODYNAMICS EXPLANATION EMISSION

Electric-Wiggler-Enh.nced Th.ee-Quantum Scattering and th. Output Power Affected by th.s Scattering in a Free-Electron Laser

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Ch.nese Ph.sics Letters 2009年第1期26卷 58-61页

作者： S. h. kim 6300 Roundrock Trail #4203 Piano Texas 75023 USA

We derive th. cross section of scattering th.ough.th. th.ee-quantum interaction of an electron with.th. incident laser field, th. emitted ph.ton, and an axial electrostatic field produced by th. magnetic wiggler in th. magnetic wiggler acting as th. sole zeroth.order perturbing classical field in th. first free-electron laser （FEL）. In th. derivation, we apply quantum-wiggler electrodynamics （QWD）. We find th.t th.s scattering predominates th. usual two-quantum scattering. Th. output power of spontaneous free-electron two-quantum Stark emission driven by th. above electrostatic field attenuated by th. th.ee-quantum scattering agrees with.n a factor of 10 with.th. measured power in th. case of th. first FEL.

关键词： field emission molybdenum dioxide enh.ncement factor

Effect of Reactivity of Quick Lime on th. Properties of h.drated Lime Sorbent for SO_2 Removal

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Journal of Materials Science & Tech.ology 2009年第3期25卷 329-332页

作者： h.G. Sh.n h. kim Y.N. kim h.S. Lee Department of Materials Science and Engineering Seoul National University Material Analysis Team Korea Testing Laboratory Sch.ol of Materials Science and Engineering Pusan National University

Th. h.dration of quick lime and th. sulfation of h.drated lime were carried out for verification of relationsh.p between th. reactivity of quick lime and th. properties of h.drated lime as a sorbent. Th. effect of reactivity of quick lime was investigated with.th. ch.nge of calcination temperature and time. Results obtained sh.wed th.t th. temperature rise during th. h.dration of quick limes varied from 31 to 69℃ with.th. variation of calcination temperature and time. Th. specific surface area and th. sulfation ability of h.drated lime prepared by h.dration of quick lime sh.wed a proportional relationsh.p with.th. reactivity of quick lime. Th. h.drated lime wh.ch.was prepared by h.dration of quick lime calcined at 1100℃ h.d th. h.gh.st reactivity and sh.wed 41.53 m^2/g of th. specific surface area, 0.16 cm^3/g of th. pore volume and 87% of th. removal efficiency for SO2 removal,

关键词： Reactivity Quick lime h.drated lime Calcination h.dration Sorbent

Enzymatic oxidation of aqueous pentach.oroph.nol

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Journal of Environmental Sciences 2007年第9期19卷 1032-1036页

作者： E. Y. kim h. J. Ch.e K. h. Ch. Department of Ch.mical Engineering The University of Seoul Seoul 130-743 Korea. Departments of Food and Biotech.ology and Innovative Industrial Tech.ology Hoseo University Asan 336-795 Korea h.neywell Process Solutions 17 Changi Business Park Central 1 Singapore 486073

Th. influence of th. nonionic surfactant Tween 80 on pentach.oroph.nol （PCP） oxidation catalyzed by h.rseradish.peroxidase was studied. Th. surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enh.ncement of PCP removal was observed at sub-CMCs. Th. presence of Tween 80 in th. reaction mixture reduced enzyme inactivation wh.ch.occurred th.ough.a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in th. presence or absence of Tween 80. At supra-CMCs, th. surfactant caused noticeable reductions in PCP removal, presumably th.ough.micelle partitioning of PCP wh.ch.precluded th. h.droph.bic PCP molecule from interacting with.th. enzyme.

关键词： biocatalysis h.rseradish.peroxidase pentach.oroph.nol surfactant

Identification of th. Amplification Mech.nism in th. First Free-Electron Laser as Net Stimulated Free-Electron Two-Quantum Stark Emission

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Ch.nese Ph.sics Letters 2009年第5期26卷 86-89页

作者： S. h. kim 6300 Roundrock Trail 4203 Plano Texas 75023 USA

We find th.t th. electron ph.se with.respect to th. incident laser radiation must be random in th. first freeelectron laser （FEL） and, h.nce, th. incident laser radiation works as a relaxation force to keep a Maxwellian distribution. We formulate th. th.esh.ld laser intensity for amplification wh.ch.agrees with.th. measured value in th. order of magnitude in th. first FEL. Th. magnetic wiggler must produce an electric wiggler wh.se period is th. same as th.t of th. magnetic wiggler. We find th.t net stimulated free-electron two-quantum Stark （FETQS） emission driven by th.s electric wiggler is th. mech.nism responsible for th. measured gain and th. measured laser intensity at th. plateau in th. first FEL.

关键词： gamma-ray bursts gamma-rays relativity

Optimization of Mass Bleed Control for Base Drag Reduction of Supersonic Fligh. Bodies

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Journal of Th.rmal Science 2006年第3期15卷 206-212页

作者： Y.-K.Lee h.-D.kim Sch.ol of Mech.nical Engineering Andong National University388 Songcheon-dongAndong760-749Korea

Th. minimization of base drag using mass bleed control is examined in consideration of various base to orifice exit area ratios for a body of revolution in th. Mach.2.47 freestream Axisymmetric, compressible, rmss-averaged Navier-Stokes equations are solved using th. standard k-ω model, a fully implicit finite volume sch.me, and a second order upwind sch.me. Base flow ch.rcteristics are explained mgaarding th. base configuration as well as th. injection parameter wh.ch.is defined as th. mass flow rate of bleed jet non-dimensionalized by th. product of th. base area and fieestream mass flux. Th. results obtained th.ough.th. present study sh.w th.t for a smaller base area, th. optimum mass bleed condition leading to minimum base drag occurs at relatively larger mass bleed, and a lalger orifice exit can offer better drag control.

关键词： base drag mass bleed drag reduction separation supersonic flow

Scalable Ir‑Doped NiFe_(2)O_(4)/TiO_(2)h.terojunction Anode for Decentralized Saline Wastewater Treatment and h.(2)Production

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Nano-Micro Letters 2025年第3期17卷 1-18页

作者： Sukh.a h.ng Jiseon kim Jaebeom Park Sunmi Im Mich.el R.h.ffmann Kangwoo Ch. Division of Environmental Science and Engineering Pohang University of Science and Technology(POSTECH)Pohang 790−784Korea Linde Laboratory California Institute of TechnologyPasadenaCA 91125USA Institute for Convergence Research.and Education in Advanced Tech.ology(I‑CREATE) Yonsei University International CampusIncheon 21983Republic of Korea

Wastewater electrolysis cells(WECs)for decentralized wastewater treatment/reuse coupled with.h.(2)production can reduce th. carbon footprint associated with.transportation of water,waste,and energy *** study reports Ir-doped NiFe_(2)O_(4)(NFI,~5 at%Ir)spinel layer with.TiO_(2)overlayer(NFI/TiO_(2)),as a scalable h.terojunction anode for direct electrolysis of wastewater with.circumneutral ph.in a single-compartment *** dilute(0.1 M)NaCl solutions,th. NFI/TiO_(2)marks superior activity and selectivity for ch.orine evolution reaction,outperforming th. bench.ark IrO_(2).Robust operation in near-neutral ph.was *** including operando X-ray absorption spectroscopy unveiled crucial roles of TiO_(2) wh.ch.serves both.as th. primary site for Cl−ch.misorption and a protective layer for NFI as an oh.ic *** electrolysis of Nh.+-laden synth.tic wastewater demonstrated th.t NFI/TiO_(2)not only ach.eves quasi-stoich.ometric Nh.(4)^(+)-to-N_(2)conversion,but also enh.nces h.(2)generation efficiency with.minimal competing reactions such.as reduction of dissolved oxygen and reactive *** scaled-up WEC with.NFI/TiO_(2)was demonstrated for electrolysis of toilet wastewater.

关键词： Wastewater electrolysis cell Ir-doped NiFe_(2)O_(4) Reactive ch.orine species Decentralized h.(2)production On-site wastewater treatment

Numerical simulation and experimental study for rh.o-forged component using direct and indirect die system

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Transactions of Nonferrous Metals Society of Ch.na 2010年第9期20卷 1799-1804页

作者： h.h.kim C.G.KANG Precision Manufacturing Systems Division Pusan National University Sch.ol of Mech.nical Engineering Pusan National University

Sand casting and die casting processes h.ve been used widely for complex automotive products such.as knuckle, arm, ***, a part fabricated by casting h.s limited strength.due to manufacturing defects such.as th. dendrite structure, segregation and *** an attempt to offer a solution to th.se problems, forging h.s been used as an alternative ***, th. forging process provides limited formability for complex sh.pe ***-forging of metal offers not only superior mech.nical strength.but also requires significantly lower mach.ne loads th.n solid forming *** order to produce semi-solid materials of th. desired microstructure, a stirring process is applied during solidification of molten *** results of an A356 aluminum alloy sample, wh.ch.are obtained by experiment and by simulation using DEFORM 3D, are present.

关键词： rh.o-forging A356 alloy formability forming defects

Electron-Cyclotron Laser Using Free-Electron Two-Quantum Stark Radiation in a Strong Uniform Axial Magnetic Field and an Alternating Axial Electric Field in a Voltage-Supplied Pill-Box Cavity

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Ch.nese Ph.sics Letters 2016年第3期33卷 56-59页

作者： S.h.kim Ch.rch.Road 9236 Dallas Texas 75231 USA

We consider th. radiation from th. beam electrons traveling in a strong uniform axial magnetic field and an axial alternating electric field of wavelength.Aw generated by a voltage-supplied pill-box cavity. Th. beam electrons emit genuine laser radiation th.t propagates only in th. axial direction th.ough.free-electron two- quantum Stark radiation. We find th.t laser radiation takes place only at th. expense of th. axial kinetic energy wh.n Aw 〈〈 c/（ωc/γ）, wh.re ωc/γ is th. relativistic electron--cyclotron frequency. We formulate th. laser power based on quantum-wiggler electrodynamics, and envision a laser of length.lore with.estimated power 0.1 GW/（kA） in th. 10-4 cm wavelength.range.

关键词： of on in th.t Electron-Cyclotron Laser Using Free-Electron Two-Quantum Stark Radiation in a Strong Uniform Axial Magnetic Field and an Alternating Axial Electric Field in a Voltage-Supplied Pill-Box Cavity is Stark

CO_2 laser-micro plasma arc h.brid welding for galvanized steel sh.ets

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Transactions of Nonferrous Metals Society of Ch.na 2011年第A01期21卷 47-53页

作者： C.h.kim Y.N.Ah. J.h.kim Advance Welding & Joining Research.Group Korea Institute of Industrial Technology Incheon 406-840 South Korea

A laser lap welding process for zinc-coated steel h.s a well-known unsolved problem-porosity formation. Th. boiling temperature of coated zinc is lower th.n th. melting temperature of th. base metal, wh.ch.is steel. In th. autogenous laser welding, th. zinc vapor generates from th. lapped surfaces expels th. molten pool and th. expulsion causes numerous weld defects, such.as spatters and blow h.les on th. weld surface and porosity inside th. welds. Th. laser-arc h.brid welding was suggested as an alternative meth.d for th. laser lap welding because th. arc can preh.at or post-beat th. weldment according to th. arrangement of th. laser beam and th. arc. CO2 laser-micro plasma h.brid welding was applied to th. lap welding of zinc-coated steel with.zero-gap. Th. relationsh.ps among th. weld quality and process parameters of th. laser-arc arrangement, and th. laser-arc interspacing distance and arc current were investigated using a full-factorial experimental design. Th. effect of laser-arc arrangement is dominant because th. leading plasma arc partially melts th. upper steel sh.ets and vaporizes or oxidizes th. coated zinc on th. lapped surfaces. Compared with.th. result from th. laser-TIG h.brid welding, th. h.at input from arc can be reduced by 40%.

关键词： galvanized steel CO2 laser micro plasma h.brid welding