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Denitrification Rates and Their Controlling Factors in Streams of the Han River Basin with Different Land-Use Patterns

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Pedosphere 2014年第4期24卷 516-528页

作者： S.P.jung y.j.KIM H.KANG School of Civil and Environmental Engineering Yonsei UniversitySeoul 120-749(Korea) River and Coastal Research Division Korea Institute of Construction TechnologyGoyang 211-712(Korea)

Land-use patterns can affect various nutrient cycles in stream ecosystems, but little information is available about the effects of urban development on denitrification processes at the watershed scale. In the presented study, we investigated the controlling factors of denitrification rates within the streams of the Han River Basin, Korea, with different land-use patterns, in order to enhance the effectiveness of water resource management strategies. Ten watersheds were classified into three land-use patterns （forest, agriculture and urban） using satellite images and geographic information system techniques, and in-situ denitrification rates were determined using an acetylene blocking method. Additionally, sediment samples were collected from each stream to analyze denitrifier communities and abundance using molecular approaches. In-situ denitrification rates were found to be in the order of agricultural streams （289.6 mg N20-N m-2 d-1）〉 urban streams （157.0 mg N20-N m-2 d-1）〉 forested streams （41.9 mg N20-N m-2 d-l）. In contrast, the average quantity of denitrifying genes was the lowest in the urban streams. Genetic diversity of denitrifying genes was not affected by watershed land-use pattern, but exhibited stream-dependent pattern. More significance factors were involved in denitrification in the sites with higher denitrification rates. Multiple linear regression analysis revealed that clay, dissolved organic carbon and water contents were the main factors controlling denitrification rate in the agricultural streams, while dissolved organic carbon was the main controlling factor in the urban streams. In contrast, temperature appeared to be the main controlling factor in the forested streams.

关键词： denitrifier communities denitrifying genes nutrient cycle stream ecosystem

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Design Features and Commissioning of the Versatile Experiment Spherical Torus (VEST) at Seoul National University

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Plasma Science and Technology 2013年第3期15卷 244-251页

作者： K.j.CHUNG y.H.AN B.K.jung H.y.LEE C.SUNG y.S.NA T.S.HAHM y.S.HWANG Department of Nuclear Engineering Seoul National University

A new spherical torus called VEST （Versatile Experiment Spherical Torus） is designed, constructed and successfully commissioned at Seoul National University. A unique design feature of the VEST is two partial solenoid coils installed at both vertical ends of a center stack, which can provide sufficient magnetic fluxes to initiate tokamak plasmas while keeping a low aspect ratio configuration in the central region. According to initial double null merging start-up scenario using the partial solenoid coils, apprdpriate p6wer supplies for driving a toroidal field coil, outer poloidal field coils, and the partial solenoid Coils are fabricated and successfully commissioned. For reliable start-up, a pre-ionization system with two cost-effective homemade magnetron power supplies is also prepared. In addition, magnetic and spectroscopic diagnostics with appropriate data acquisition and control systems are well prepared for initial operation of the device. The VEST is ready for tokamak plasma operation by completing and commissioning most of the designed components.

关键词： spherical torus partial solenoids double null merging start-up

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Relation between etching profile and voltage-current shape of sintered SiC etching by atmospheric pressure plasma

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Plasma Science and Technology 2019年第4期21卷 137-144页

作者： D C SEOK S R yOO K I LEE y S CHOI y H jung Plasma Technology Research Center National Fusion Research InstituteGunsan City 54004Republic of Korea

Sintered silicon carbide(SiC)was etched by a dielectric barrier discharge source.A high voltage bipolar pulse was used with helium gas for the plasma *** stable filament plasma was generated and could be used for SiC *** the processing gas(NF3)mixing rate increased,the width and depth of the etching profile became narrower and *** differentiated V-Q Lissajous method was used for measuring the capacitances(Ceq)of the electrode after the plasma turned *** width of the etching profile was proportional to *** the current peak value/smx of the substrate current in creased,the volume removal rate of SiC *** etch depth was proportional to the ratio of/smx to ***,because of the different characteristics of the plasma disks on SiC substrate by the voltage polarity,the etching profile was ***,in high NF3 mixing process,the etching profile became stable and deeper.

关键词： dielectric barrier discharge silicon carbide plasma etching、filament discharge,surface charge

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Fault detection method with PCA and LDA and its application to induction motor

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journal of Central South University 2010年第6期17卷 1238-1242页

作者： jung D y LEE S M 王洪梅 KIM j H LEE S H Daeho Tech Company Limited Department of Electronics Engineering Inha University School of Mechatronics Changwon National University

A feature extraction and fusion algorithm was constructed by combining principal component analysis(PCA) and linear discriminant analysis(LDA) to detect a fault state of the induction *** yielding a feature vector with PCA and LDA from current signal that was measured by an experiment,the reference data were used to produce matching *** a diagnostic step,two matching values that were obtained by PCA and LDA,respectively,were combined by probability model,and a faulted signal was finally *** the proposed diagnosis algorithm brings only merits of PCA and LDA into relief,it shows excellent performance under the noisy *** simulation was executed under various noisy conditions in order to demonstrate the suitability of the proposed algorithm and showed more excellent performance than the case just using conventional PCA or LDA.

关键词： principal component analysis (PCA) linear discriminant analysis (LDA) induction motor fault diagnosis fusionalgorithm

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Deposition of Nano-Scaled Coatings Using Inductively Coupled Plasma

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journal of Rare Earths 2004年第Z2期22卷 153-156页

作者： D H jung B Park j j Lee School of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 151-744Korea School of Materials Science and EngineeringCollege of EngineeringSeoul National UniversitySeoul 151-744Korea School of Materials Science and EngineeringCollege of EngineeringSeoul National UniversitySeoul 151-744Korea

Nano-scaled Ti-B-N coatings could be produced by inductively coupled plasma (ICP) assisted magnetron spurtering. The properties and microstructure of the coating can be changed drastically by applying ICP to conventional magnetron sputtering. In this work, an internal type rf ICP process is used. The core of this technology is the efficient production and control of self-depositing ions and reactive gas ions by an induced electric field. Ti-B-N coatings were prepared by using a TiB2 target and a gas mixture of N2 and Ar at 200 ℃ and a pressure of 60 mTorr. In addition to ICP, the effect of the substrate bias voltage on the structure and properties of the coating was investigated. By applying ICP and a bias voltage to the substrate the hardness of the Ti-B-N coating is increased by more than 75 GPa, as a result of enhanced ionization in the plasma. The Ti-B-N coating, which has the highest hardness, shows the best surface uniformity and a very dense structure with a grain size of 3 nm. This sample also shows a high crystallinity compared to the coating prepared using other deposition parameters.

关键词： nano-scaled coatings industively conpled plasma

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Isolation of intact bacteria from blood by selective cell lysis in a microfluidic porous silica monolith

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Microsystems & Nanoengineering 2019年第1期5卷 418-428页

作者： jung y.Han Michael Wiederoder Don L.DeVoe Department of Mechanical Engineering University of MarylandCollege ParkMD 20742USA Department of Chemical and Biomolecular Engineering University of MarylandCollege ParkMD 20742USA Fischell Department of Bioengineering University of MarylandCollege ParkMD 20742USA

Rapid and efficient isolation of bacteria from complex biological matrices is necessary for effective pathogen identification in emerging single-cell ***,we demonstrate the isolation of intact and viable bacteria from whole blood through the selective lysis of blood cells during flow through a porous silica *** mechanical hemolysis is achieved while providing passage of intact and viable bacteria through the monoliths,allowing size-based isolation of bacteria to be performed following selective lysis.A process for synthesizing large quantities of discrete capillary-bound monolith elements and millimeter-scale monolith bricks is described,together with the seamless integration of individual monoliths into microfluidic *** impact of monolith morphology,geometry,and flow conditions on cell lysis is explored,and flow regimes are identified wherein robust selective blood cell lysis and intact bacteria passage are achieved for multiple gram-negative and gram-positive *** technique is shown to enable rapid sample preparation and bacteria analysis by single-cell Raman *** selective lysis technique presents a unique sample preparation step supporting rapid and culture-free analysis of bacteria for the point of care.

关键词： silica porous quantities

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Mg-Al Alloys Manufactured by Casting and Hot Working Process

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journal of Materials Science & Technology 2008年第1期24卷 96-98页

作者： j.M.Kim j.H.jun W.j.jung Department of Applied Materials Eng. Hanbat National University Daejeon 305-719 Korea Light Materials Team Korea Institute of Industrial Technology Incheon 406-800 Korea

Mechanical properties of Mg-Al based alloys at different fabrication state,namely as-cast,hot rolled,and annealed,were investigated to develop the alloys that are suitable for the casting/hot working ***- imental results indicated that the castability such as hot cracking resistance tends to improve with increasing the aluminum ***,the elongation at elevated temperatures was observed to decrease as the AI content increases,implying difficulties in hot forming.A small amount of Zr additions could significantly enhance the room temperature mechanical properties of hot-rolled Mg-6%Al-1%Zn *** tendency of remarkable grain coarsening at high temperatures was effectively reduced by the Zr *** analyses suggested that very fine Al-3Zr precipitates formed in the Zr-added alloy are responsible for the obtained results.

关键词： Magnesium Casting Forming Tensile properties

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State estimation for neural neutral-type networks with mixed time-varying delays and Markovian jumping parameters

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Chinese Physics B 2012年第10期21卷 29-37页

作者： S.Lakshmanan ju H.Park H.y.jung P.Balasubramaniam Department of Information and Communication Engineering/Electrical Engineering Yeungnam University214-1 Dae-DongKyongsan 712-749Republic of Korea Department of Mathematics Gandhigram Rural Institute-Deemed UniversityGandhigram - 624 302TamilnaduIndia

This paper is concerned with a delay-dependent state estimator for neutral-type neural networks with mixed timevarying delays and Markovian jumping *** addressed neural networks have a finite number of modes,and the modes may jump from one to another according to a Markov *** construction of a suitable Lyapunov-Krasovskii functional,a delay-dependent condition is developed to estimate the neuron states through available output measurements such that the estimation error system is globally asymptotically stable in a mean *** criterion is formulated in terms of a set of linear matrix inequalities（LMIs）,which can be checked efficiently by use of some standard numerical packages.

关键词： neural networks state estimation neutral delay Markovian jumping parameters

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Partition method and experimental validation for impact dynamics of flexible multibody system

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Acta Mechanica Sinica 2018年第3期34卷 482-492页

作者： j.y.Wang Z.y.Liu j.Z.Hong School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong University

The impact problem of a flexible multibody system is a non-smooth, high-transient, and strong-nonlinear dynamic process with variable boundary. How to model the contact/impact process accurately and efficiently is one of the main difficulties in many engineering applications. The numerical approaches being used widely in impact analysis are mainly from two fields： multibody system dynamics （MBS） and computational solid mechanics （CSM）. Approaches based on MBS provide a more efficient yet less accurate analysis of the contact/impact problems, while approaches based on CSM are well suited for particularly high accuracy needs, yet require very high computational effort. To bridge the gap between accuracy and efficiency in the dynamic simulation of a flexible multibody system with contacts/impacts, a partition method is presented considering that the contact body is divided into two parts, an impact region and a non-impact region. The impact region is modeled using the finite element method to guarantee the local accuracy, while the non-impact region is modeled using the modal reduction approach to raise the global efficiency. A three-dimensional rod-plate impact experiment is designed and performed to validate the numerical results. The principle for how to partition the contact bodies is proposed： the maximum radius of the impact region can be estimated by an analytical method, and the modal truncation orders of the non-impact region can be estimated by the highest frequency of the signal measured. The simulation results using the presented method are in good agreement with the experimental results. It shows that this method is an effec-rive formulation considering both accuracy and efficiency. Moreover, a more complicated multibody impact problem of a crank slider mechanism is investigated to strengthen this conclusion.

关键词： Partition method Impact dynamics Experimental investigation Efficiency and accuracy Partition principle

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Revealing the contribution of basilar membrane's biological activity to the mechanism of the cochlear phonosensitive amplification

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Applied Mathematics and Mechanics(English Edition) 2023年第5期44卷 823-840页

作者： j.y.LIANG Wenjuan yAO Genomic Medicine Institute Lerner Research InstituteCleveland Clinic FoundationClevelandOH 44106U.S.A. Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai 200072China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200072China

Explaining the mechanism of the cochlear active phonosensitive amplification has been a major problem in *** basilar membrane(BM)is the key *** 1960,Nobel Laureate von B′ek′esy first discovered BM's traveling wave *** that time,BM's models only have considered the traveling wave but not the biological ***,a new model considering changes of BM's stiffness in space and time is established based on the immersed boundary method to describe its biological *** not only reproduces the results of traveling wave motion but also explains the mechanization on the generation of traveling *** important discovery is that changes of BM's stiffness in space and time will cause the unstable global resonance,which will induce amplification of sounds in *** important inference is that biological activity shall be included in the application of mechanical principles to the analysis of life,which is the essential difference between biomechanics and general mechanics.

关键词： basilar membrane(BM) biological activity mechanical analysis cochlear phonosensitive amplification

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