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EStImAtION OF SOIL EROSION IN A RESERVOIR WAtERShED USING 137CS FALLOUt RADIONUCLIDE

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International Journal of Sediment Research 2007年第4期22卷 304-317页

作者： y. J. ChIU A. m. BORGhUIS h. y. lee Dept. of Civil Engineering National Taiwan Univ. Taipei Taiwan China 2. Utrecht Univ. Department of Physical Geography Heidelberglaan 2 3584 CS Utrecht The Netherlands 3. Dept. of Civil Engineering and Hydraulic Research Laboratory National Taiwan Univ. Taipei Taiwan China

Sedimentation from soil erosion is a critical reservoir watershed management issue. Due to the difficulty of field investigations, empirical formulas are commonly used to estimate the soil erosion rate. however, these estimations are often far from accurate. An effective alternative to estimating soil erosion is to analyze the spatial variation of 137Cs inventory in the soil. 137Cs can be adsorbed by.t.e soil and is widely assumed to change its distribution only when disturbed by rainfall and h.m.n activities. thus, 137Cs distributed in soils can be a useful environmental tracer to estimate soil erosion. In this study, the net soil loss estimate is 108,346 t/yr and the gross erosion and net erosion rates are 10.1 and 9 t/ha yr respectively. the sediment delivery ratio is therefore estimated to be 0.9 based on the two erosion rates. Because of the steep hillsides in the watershed, only 10% of the sediment yield stayed in the deposition sites and 90% was transported to the river as the sediment output. Soil erosion estimates from spatial variations of the 137Cs activity in the Baishi river watershed showed satisfactory accuracy when compared to sediment yield data. Using soil 137Cs concentrations is therefore a feasible method for estimating soil loss or deposition in taiwan. Data sampling, analysis and result of this approach are given in this paper.

关键词： Soil erosion Radionuclide 137Cs Baishi watershed Spatial distribution Sediment yield

Optimization of Casting Process for heat and Abrasion Resistant Large Gray Iron Castings

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tsinghua Science and technology 2008年第2期13卷 152-156页

作者： S. m. yoo y. S. Cho C. C. lee J. h. kim C. h. kim J. K. Choi Center for E-Design Korea Institute of Industrial Technology Kwanghee Casting mfg. Co. R&D Center Doosan Engine Co. Ltd.

Numerical simulations were used to optimize the casting design and conditions for large cast iron castings for marine engines, Simulations of the mold filling and solidification sequences were used to analyze the problems of previous casting conditions with.m.rked improvements for large cylinder liner parts, the amount and positions of chills were optimized to improve the mechanical properties and to minimize the shrinkage and micro porosity in the castings. Ultra sonic testing, penetration testing, and mechanical property.t.sting show no defects in the castings with the productivity significantly increased.

关键词： gray cast iron numerical simulation marine engine cylinder liner chill casting design optimization

Anisotropic NdFeB magnet Fabricated by Single Stroke hot Deformation

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Journal of materials Science & technology 2000年第2期16卷 129-130页

作者： y.Li (Chungnam National University, taejon, Korea) y.B.kim (Korea Research Institute of Standards and Science, taejon, Korea) m.J.kim, m.S.Song, J.h.yang, t.K.kim and C.O.kim (Chungnam National University, taejon, Korea) Chungnam National University Taejon South Korea Korea Research Institute of Standards and Science Taejon South Korea

the general hot deformation process consists of two steps, hot pressing and die-upsetting in order to obtain the anisotropic NdFeB magnet. this is the first report that the high anisotropy NdFeB magnets can be fabricated by single stroke hot deforming the isotropic magnet. the magnetic properties of those materials are: coercivity ihc ～11 kOe, remanence Br ～12 kG, and the maximum energy product (Bh.m.x ～28 ***.

关键词： NdFeB Anisotropic NdFeB magnet Fabricated by Single Stroke hot Deformation

Design of low noise airfoil with high aerodynamic performance for use on small wind turbines

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Science China(technological Sciences) 2010年第1期53卷 75-79页

作者： taehyung kim Seungmin lee hogeon kim Soogab lee Department of mechanical and Aerospace Engineering Seoul National University599 Gwanak-roGwanak-guSeoul 151-742Republic of Korea

Wind power is one of the most reliable renewable energy sources and internationally installed capacity is increasing radically every *** wind power has been favored by.t.e public in general,the problem with the impact of wind turbine noise on people living in the vicinity of the turbines has been *** noise wind turbine design is becoming more and more important as noise is spreading more adverse effect of wind turbine to *** paper demonstrates the design of 10 kW class wind turbines,each of three blades,a rotor diameter 6.4 m,a rated rotating speed 200 r/min and a rated wind speed 10 m/*** optimized airfoil is dedicated for the 75% spanwise position because the dominant source of a wind turbine blade is trailing edge noise from the outer 25% of the *** computations are performed for incompressible flow and for mach number at 0.145 and for Reynolds numbers at 1.02×106 with a lift performance,which is resistant to surface contamination and turbulence *** objectives in the design process are to reduce noise emission,while sustaining high aerodynamic *** broadband noise sources are predicted by semi-empirical formulas composed of the groundwork by Brooks et *** Lowson associated with typical wind turbine operation *** the airfoil redesign process,the aerodynamic performance is analyzed to reduce the wind turbine power *** results obtained from the design process show that the design method is capable of designing airfoils with reduced noise using a commercial 10 kW class wind turbine blade airfoil as a ***,the new optimized airfoil showing 2.9 dB reductions of total sound pressure level(SPL) and higher aerodynamic performance are achieved.

关键词： wind turbine aerodynamic noise airfoil self noise low noise airfoil design

Rational strategy for power doubling of monolithic multijunction III-V photovoltaics by accommodating attachable scattering waveguides

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Light(Science & Applications) 2024年第11期13卷 2734-2744页

作者： Shin hyung lee hyo Jin kim Jae-hyun kim Gwang yeol Park Sun-Kyung kim Sung-min lee School of Electrical Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Optoelectronic Convergence Research Center Korea Photonics Technology InstituteGwangju 61007Republic of Korea Department of Applied Physics Kyung Hee UniversityYongin 17104Republic of Korea Department of Electrical Engineering Hanyang UniversitySeoul 04763Republic of Korea Division of materials Science and Engineering Hanyang UniversitySeoul 04763Republic of Korea

While waveguide-based light concentrators offer significant advantages,their application has not been considered an interesting option for assisting multijunction or other two-terminal tandem solar *** this study,we present a simple y.t.effective approach to enhancing the output power of transfer-printed multijunction InGaP/GaAs solar *** utilizing a simply combinable waveguide concentrator featuring a coplanar waveguide with BaSO4 mie scattering elements,we enable the simultaneous absorption of directly illuminated solar flux and indirectly waveguided *** deployment of cells is optimized for front-surface photon collection in monofacial *** sy.t.matic comparisons across various waveguide parameters,supported by both experimental and theoretical quantifications,we demonstrate a remarkable improvement in the maximum output power of a 26%-efficient cell,achieving an enhancement of~93%with the integration of the optimal scattering ***,a series of supplementary.t.sts are conducted to explore the effective waveguide size,validate enhancements in arrayed cell module performance,and assess the drawbacks associated with rear *** findings provide a comprehensive understanding of our proposed approach towards advancing multi-junction photovoltaics.

关键词： waveguide scattering power

Decomposing class responsibilities using distance-based method similarity

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Frontiers of Computer Science 2016年第4期10卷 612-630页

作者： Junha lee Dae-Kyoo kim Suntae kim Sooyong PARK Department of Electronic and Computer Engineering Oakland University Rochester M148309 USA Department of Computer Science and Engineering Oakland University Rochester M148309 USA Department of Software Engineering Chonbuk National University Chonju 561-756 South Korea Department of Computer Science and Engineering Sogang University Seoul 121-741 South Korea

Cohesion is a design quality.t.at has a great im- pact on the posterior development and maintenance. As software evolves, the cohesion of the sy.t.m becomes weaker due to the changes introduced during evolution. Over evolution, a single responsibility class may be unintentionally assigned other responsibilities, which.m.kes the class less cohesive and more complex and consequently increases the complexity of the entire sy.t.m. there has been much work on decomposing class responsibilities based on internal class relationships such as method-attribute referencing and internal method calls. however, object-oriented sy.t.ms involve significant external class relationships carrying important behavioral semantics, which should be taken into account in identifying class responsibilities. In this paper, we present a novel approach for identifying and decomposing classes responsibilities based on method similarity using both internal and external class relationships. We extend the existing work for measuring similarity of internal class relationships and present a distance-based method for measuring external class relationships. We evaluate the approach using three open source applications -- Jmeter, JhotDraw, and ArgoUmL. the evaluation shows that the presented approach improves precision over the existing work. We validate the results using independent samples t-test and ANOVA applied to a set of hypotheses. the validation confirms that the results are statistically significant.

关键词： class decomposition cohesion external rela-tionships identifying responsibility method similarity

Experimental and Numerical Investigation on Impact Performance of Carbon Reinforced Aluminum Laminates

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Journal of materials Science & technology 2010年第4期26卷 327-332页

作者： S.h. Song y.S. Byun t.W. Ku W.J. Song J. kim B.S. Kang National Core Research Center Pusan National University Busan 609-735 Korea Dept. of Aerospace Engineering Pusan National University Busan 609-735 Korea Industrial Liaison Innovation Cluster Pusan National University Busan 609-735 Korea

It is known that fiber metal laminates （FmL） as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a relatively low density. therefore, the mechanical components using FmL can contribute the enhanced safety level of the sound construction toward the whole body. In this study, the impact performance of carbon reinforced aluminum laminates （CARAL） is investigated by experiments and numerical simulations. Drop weight tests are carried out with the weight of 4.7 kg at the speed of 1 and 2 m/s, respectively. Dynamic non-linear transient analyses are also accomplished using a finite element analysis software, ABAQUS. the experiment results and numerical results are compared with impact load-time histories. Also, energy.t.me histories are applied to investigate the impact performance of CARAL.

关键词： Fiber metal laminates (FmL) Carbon reinforced aluminum laminates (CARAL) Numerical simulation Impact performance

Aqueous-processable,naphthalene diimide-based polymers for eco-friendly fabrication of high-performance,n-type organic electrolyte-gated transistors

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Science China Ch.m.stry 2022年第5期65卷 973-978页

作者： Dahyun Jeong min Je kim Seungjin lee Jin-Woo lee youngwoong kim hyeong Jun kim Jeong ho Cho Bumjoon J.kim Department of Ch.m.cal and Biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Department of Ch.m.cal and Biomolecular Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Ch.m.cal and Biomolecular Engineering Sogang UniversitySeoul 04107Republic of Korea

Organic electrolyte-gated transistors(OEGts) have the benefits of low power consumption and large current ***,the electrical performance of n-type OEGts lags far behind that of p-type *** this study,we design a series of polymers,P(NDItEG-t) and P(NDImtEG-t),comprising a naphthalene diimide backbone for n-type charge transport and oligo(ethylene glycol)(OEG) side chains for high ionic conductivity and eco-friendly solution *** incorporation of the OEG chain facilitates the electroch.m.cal doping of the semiconductor by ions to realize high-performance,n-type ***,in OEGts,P(NDItEG-t) achieves a high electron mobility of 1.0 × 10^(-1) cm^(2) V^(-1) s^(-1),which represents the highest value reported for solution-processed,n-type *** is noted that the fabrication of the OEGts is achieved by solution processing with eco-friendly ethanol/water mixtures in virtue of the hydrophilic OEG *** work demonstrates the molecular design of the P(NDItEG-t) polymer and its significant ability.t. produce aqueous-processable,high-performance,and n-type OEGts.

关键词： organic electrolyte-gated transistors n-type transistors oligo(ethylene glycol)polymers eco-friendly solution process high electron mobility

tribological properties of multilayer tetrahedral amorphous carbon coatings deposited by filtered cathodic vacuum arc deposition

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Friction 2021年第5期9卷 1292-1302页

作者： young-Jun JANG Jae-Il kim Wooyoung lee Jongkuk kim Department of Extreme Environmental Coatings Surface Technology DivisionKorea Institute of Materials Science(KIMS)Gyeongnam-do 51508Republic of Korea Department of mechanical Science and Engineering Graduate School of EngineeringNagoya UniversityNagoya 464-8603Japan

tetrahedral amorphous carbon(ta‐C)has emerged as an excellent coating material for improving the reliability of application components under high normal ***,we present the results of our investigations regarding the mechanical and tribological properties of a 2‐μm‐thick multilayer ta‐C coating on high‐speed steel *** composed of alternating soft and hard layers are fabricated using filtered a cathodic vacuum arc with alternating substrate bias voltages(0 and 100 V or 0 and 150 V).the thickness ratio is discovered to be 1:3 for the sp2‐rich and sp3‐rich *** results show that the hardness and elastic modulus of the multilayer ta‐C coatings increase with the sp3 content of the hard *** hardness reached approximately 37 GPa,whereas an improved toughness and a higher adhesion strength(>29 N)are *** friction performance(μ=0.07)of the multilayer coating is similar to that of the single layer ta‐C thick coating,but the wear rate(0.13×10^(–6) mm^(3)/(N∙m))improved under a high load of 30 *** further demonstrate the importance of the multilayer structure in suppressing crack propagation and increasing the resistance to plastic deformation(h3/E2)ratio.

关键词： tetrahedral amorphous carbon(ta‐C) filtered cathodic vacuum arc deposition multilayer coatings alternating substrate bias voltage wear resistance plastic deformation resistance