Redescription of free-living marine nematode, dracograllus filipjevi allen and noffsinger, 1978 (nematoda: draconematidae) from korea     

Hyun Soo Rho  Dong-Sung Kim  Won Kim 《Ocean Science Journal》2006,41(3):163-173

A draconematid nematode species,Dracograllus filipjevi Allen and Noffsinger, 1978, is described from the washings of shallow littoral coralline algae at Guryongpo in the eastern coast of Korea. This species is recognized by the following characteristics: larger body size, number of posterior sublateral adhesion tubes (9 in male and 12-13 in female) and subventral adhesion tubes (8-9 in male and 9-10 in female), the absence of cephalic acanthiform setae on rostrum, the presence of longitudinally areolated body cuticle with dot-like punctations, the presence of some cuticular collar in swollen pharyngeal region, the shape of amphidial fovea (large, elongate, and loop-shaped in both sexes), the absence of preanal corniform setae, and the absence of lateral differentiation on narrow body region. Morphological features of the species using differential interference contrast photomicrographs are described in detail in the present work. This is the first report ofD. filipjevi in Korea.  相似文献   

Preface to the Special Issue:Towards Improving Understanding and Prediction of Arctic Change and Its Linkage with Eurasian Mid-latitude Weather and Climate     

Xiangdong ZHANG  Thomas JUNG  Muyin WANG  Yong LUO  Tido SEMMLER  Andrew ORR 《大气科学进展》2018,35(1):1-4

正The dramatic changes in the Arctic climate system during recent decades are one of the most prominent features of global climate change.Two most striking and fundamental characteristics are the amplified near-surface warming at a rate twice the global average since the mid 20th century(e.g.,Blunden and Arndt,2012;Huang et al.,2017),and the rapid  相似文献   

THEORETICAL AND EXPERIMENTAL APPROACHES TO THE GEOPHONE SPURIOUS FREQUENCY*     

SHI JUNG CHEN  CH. DALTON 《Geophysical Prospecting》1983,31(4):574-590

The geophone spurious frequency is modeled as the resonance of the planar motion of a spider spring carrying a moving mass. An analytic solution is found using the Castigliano method by assuming that the spring arm is a single-mode vibrating cantilever beam. The spring shape is found from this analysis. When the typical spring has a circumferentially varying cross-section, the Castigliano method is no longer applicable. A dimensional analysis is used as an approximate method for general design. Based on the theoretical result, a rotational fixture and a translational fixture were designed for experimental purposes. A low-noise fixture and a phase-averaging technique provide the amplitude and spurious resonance in the frequency domain. Finally, a test is run by using a rotational fixture to compare with the approximate method of spurious frequency prediction. Very good agreement between prediction and experiment is found.  相似文献   

Diagnosing the Earth     

I.J. Won 《Ground Water Monitoring & Remediation》1990,10(3):5-8

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Inversion of synthetic aperture radar data for surface scattering     

J. S. Won  W. M. Moon 《Geophysical Journal International》1992,108(2):423-432

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Case study on the three-dimensional structure of meso-scale eddy in the South China Sea based on a high-resolution model   总被引：1，自引：1，他引：0  

XIA Changshui  JUNG KyungTae  WANG Guansuo  YIN Xunqiang  GUO Jingsong 《海洋学报(英文版)》2016,35(2):29-38

Meso-scale eddies are important features in the South China Sea(SCS). The eddies with diameters of 50–200 km can greatly impact the transport of heat, momentum, and tracers. A high-resolution wave-tide-circulation coupled model was developed to simulate the meso-scale eddy in the SCS in this study. The aim of this study is to examine the model ability to simulate the meso-scale eddy in the SCS without data assimilations The simulated Sea Surface Height(SSH) anomalies agree with the observed the AVISO SSH anomalies well. The simulated subsurface temperature profiles agree with the CTD observation data from the ROSE(Responses of Marine Hazards to climate change in the Western Pacific) project. The simulated upper-ocean currents also agree with the main circulation based on observations. A warm eddy is identified in winter in the northern SCS. The position and domain of the simulated eddy are confirmed by the observed sea surface height data from the AVISO. The result shows that the model has the ability to simulate the meso-scale eddy in the SCS without data assimilation.The three-dimensional structure of the meso-scale eddy in the SCS is analyzed using the model result. It is found that the eddy center is tilted vertically, which agrees with the observation. It is also found that the velocity center of the eddy does not coincide with the temperature center of the eddy. The result shows that the model has the ability to simulate the meso-scale eddy in the SCS without data assimilations. Further study on the forming mechanism and the three-dimensional structure of the meso-scale eddies will be carried out using the model result and cruise observation data in the near future.  相似文献   

Groundwater occurrence on Jeju Island, Korea     

Jong-Ho Won  Jin-Yong Lee  Ji-Wook Kim  Gi-Won Koh 《Hydrogeology Journal》2006,14(4):532-547

Jeju Island is a volcanic island composed predominantly of permeable basalts. The island is poor in surface water but abundant in groundwater. No actual perennial streams exist and the water resources on the island are dependent almost entirely on groundwater. The groundwater bodies on the island are classified into three general categories: high level, basal and parabasal groundwaters. The parabasal groundwater is further subdivided into lower and upper parabasal groundwaters due to the position of the Seogwipo Formation, which is made up of sedimentary rocks with a low permeability. The distribution of each groundwater type was evaluated through analyses of the spatial distribution of the Seogwipo Formation and the hydraulic gradient of the groundwater. Basal groundwater emerges extensively along the coast of the eastern sector, less commonly along the coast of the western sector. Parabasal groundwater occurs extensively over most of the island except for the southern sector, where it occurs only locally in the coastal area. This paper presents a summary of several studies on the occurrence and features of groundwater resources on Jeju Island, the largest island in Korea.  相似文献   

Optimal design of added viscoelastic dampers and supporting braces     

Ji‐Hun Park  Jinkoo Kim  Kyung‐Won Min 《地震工程与结构动力学》2004,33(4):465-484

This paper presents a simultaneous optimization procedure for both viscoelastic dampers (VEDs) and supporting braces installed in a structure. The effect of supporting braces on the control efficiency of VEDs is also investigated. To apply a general gradient‐based optimization algorithm, closed‐form expressions for the gradients of objective function and constraints are derived. Also, the constraint on the dynamic behavior of a structure is embedded in the gradient computation procedure to reduce the number of variables in the optimization. From numerical analysis of an example structure, it was found that when sufficient stiffness cannot be provided for the supporting braces, the flexibility of the brace should be taken into account in the design of the VED to achieve the desired performance of the structure. It was also observed that, as a result of the proposed optimization process, the size of the supporting brace could be reduced while the additional VED size (to compensate for the loss of the control effect) was insignificant. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Semi‐active fuzzy control for seismic response reduction using magnetorheological dampers     

Kang‐Min Choi  Sang‐Won Cho  Hyung‐Jo Jung  In‐Won Lee 《地震工程与结构动力学》2004,33(6):723-736

A semi‐active fuzzy control strategy for seismic response reduction using a magnetorheological (MR) damper is presented. When a control method based on fuzzy set theory for a structure with a MR damper is used for vibration reduction of a structure, it has an inherent robustness, and easiness to treat the uncertainties of input data from the ground motion and structural vibration sensors, and the ability to handle the non‐linear behavior of the structure because there is no longer the need for an exact mathematical model of the structure. For a clipped‐optimal control algorithm, the command voltage of a MR damper is set at either zero or the maximum level. However, a semi‐active fuzzy control system has benefit to produce the required voltage to be input to the damper so that a desirable damper force can be produced and thus decrease the control force to reduce the structural response. Moreover, the proposed control strategy is fail‐safe in that the bounded‐input, bounded‐output stability of the controlled structure is guaranteed. The results of the numerical simulations show that the proposed semi‐active control system consisting of a fuzzy controller and a MR damper can be beneficial in reducing seismic responses of structures. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Upscaling polydispersed particle transport in porous media using pore network model     

Won  Jongmuk  Lee  Junghwoon  Burns  Susan E. 《Acta Geotechnica》2021,16(2):421-432

Understanding particle transport in porous media is critical in the sustainability of many geotechnical and geoenvironmental infrastructure. To date, the determination of the first-order rate coefficients in the advection–dispersion equation for simulating attachment and detachment of particles in saturated porous media typically has been relied on the result of laboratory-scale experiments. However, to determine attachment and detachment coefficients under varied hydraulic and geochemical variables, this method requires a large experimental matrix because each test provides only one set of attachment and detachment coefficients. The work performed in this study developed a framework to upscale the results obtained in pore-scale modeling to the continuum scale through the use of a pore network model. The developed pore network model incorporated variables of mean particle size, the standard deviation of particle size distribution, and interparticle forces between particles and sand grains. The obtained retention profiles using the pore network model were converted into attachment coefficients in the advection–dispersion equation for long-term and large-scale simulation. Additionally, by tracking individual particles during and after the simulation, the pore network model introduced in this study can also be employed for modeling the clogging phenomenon, as well as fundamental investigation of the impact of particle size distribution on particle retention in the sand medium.

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