• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1805-1813
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• 2010

This paper presented regarding an parametric study to investigate seismic capacity evaluation of semi-rigid steel frame infilled with composit panel. In order to propose the optimum retrofit of the steel frame, we analysed the various pattern of retrofitted steel frame subjected to weak/medium earthquake. Steel frame with composit panel was analysed by Time history analyses analysis. The model were analysed using the suites of ground motion developed by NEHRP project on steel moment resisting frame. These earthquakes consist of 20 horizontal ground acceleration record each, i.e., a 10%, 50% probability of accidence in a 50 year period. We considered the semi-rigid connection which are commonly used in field, and modeled the nonlinear connection element (GAP) between panel and frame. It was shown that how is the steel frame with composit panel effected. We also examined the response of retrofitted frame.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.567-577
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• 2018

One of problems related with water curtain cultivation (WCC) in Korea includes severe declination of groundwater levels during the peak season, and it is likely that the problem can be resolved efficiently when the connection characteristics between groundwater and stream are well understood. This study examined temperature, and oxygen/hydrogen stable isotopic compositions of the flowing groundwater to understand the connection between stream and ground water, and the influence of stream water on the nearby aquifer. This study was performed in Wangjeon-ri (Kwangseok-myon, Nonsan City), the well-known strawberry town using WCC technique. The sampling was done during February 2010 through June 2011 for both groundwaters and nearby streams. Temperature distribution pattern indicates that stream widely affected groundwater in the right part of WCC ara. In the left part, the influence of stream seems to occur narrowly near the stream. The similar phenomenon is reflected in the oxygen and hydrogen isotopic data.

• Korean Journal of Hazardous Materials
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• v.2 no.1
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• pp.31-37
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• 2014

Since the unprecedented hydrogen fluoride leak accident in 2012, there has been growing demand for customized technical information for rapid response and chemical accident management agencies including the Ministry of Environment, the National Emergency Management Agency, and the National Police Agency need more information on chemicals and accident management. In this regard, this study aims to provide reliable technical data and guidelines to initial response agencies, similar to accident management technical reports of the US and Canada. In this study, we conducted a questionnaire survey and interviews on initial response agencies like fire stations, police stations, and local governments to identify new information items for appropriate initial response and improvements of current guidelines. We also collected and reviewed the Canada's TIPS, US EPA's hydrogen fluoride documents, domestic and foreign literature on applicability tests of control chemicals, and interview data, and then produced items to be listed in the technical guidelines. In addition, to establish database of on-site technical information, we carried out applicability tests for accident control data including ① emergency shut down devide, safety guard, shut down valve, ground connection, dyke, transfer pipe, scrubber, and sensor; ② literature and field survey on distribution type and transportation/storage characteristics (container identification, valve, ground connection, etc.); ③ classification and identification of storage/transportation facilities and emergency management methodslike leak prevention, chemicals control, and cutoff or bypass of rain drainage; ④ domestic/foreign analysis methods and environmental standards including portable detection methods, test standards, and exposure limits; and ⑤ comparison/evaluation of neutralization efficiency of control chemicals on toxic substances.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.1
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• pp.27-41
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• 2023

Submerged floating tunnels must be connected to the ground to connect continents. The displacement imbalance at the shore connection between the underground bored tunnel and submerged floating tunnel can cause stress concentration, accompanying a fracture at the shore connection. The elastic joint has been proposed as a method to relive the stress concentration, however, the effect of the elastic joints on the dynamic behavior should be evaluated. In this study, the submerged floating tunnel and shore connection under dynamic load conditions were simulated through numerical analysis using a numerical model verified through a small-scaled physical model test. The resonant frequency was considered as a dynamic behavioral characteristic of the tunnel under the impact load, and it was confirmed that the stiffness of the elastic joint and the resonant frequency exhibit a power function relationship. When the shore connection is designed with a soft joint, the resonant frequency of the tunnel is reduced, which not only increases the risk of resonance in the marine environment where a dynamic load of low frequency is applied, but also greatly increases the maximum velocity of tunnel when resonance occurs.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.185-187
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• 2000

Fault current is flowed into 154/23kV M. Tr when line-to-ground fault occurs in power system. NGR(Neutral Grounded Reactor) is set up in order to prevent M.Tr fault by limiting magnitude of fault currents. Here, disconnection of NGR causes voltage increase by L-C resonance and line-to-ground fault in an unearthed system results in voltage increase at healthy phases. So Over Voltage Ground Relay(OVGR) is used for tripping M.Tr. Also, buses at second phases of M.Trs are all connected with section circuit breakers closed for the purpose of parallel operation and load shedding. In case of speciality buses are comprised of power cable in part for GIS connection. When no-load charged cable or bus is open by a section CB, unbalanced voltage charged on the bus is induced. Also discrepant opening time for circuit breakers on different phases gives rise to unbalanced zero sequence voltage. It was observed that this zero sequence voltage detected in the 22.9kV P.T (Potential Transformer for bus) mal-operated 59GT and tripped M.Tr. The zero sequence voltage of which vanishing time is longer than relay operating time came out by EMTDC simulation. Also, it was shown that the voltage waves of actual test are similar to those of simulation. On the basis of above results, R-C circuit complement on the relay without any effect on a power system made operating time of the relay longer than vanishing time of distorted waves. Consequently, operating time of the relay was delayed and magnitude of distorted waves was decreased by increasing time constant of the relay.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.1-8
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• 2003

Two types of ground-water sampling techniques for CFCs (chlorofluorocarbons) analysis, the cold-welded copper tube method and flame-sealed borosilicate glass ampule method, were compared and evaluated. CFCs concentrations by the copper tube method showed a poor reproducibility among triplicates whereas those by the glass ampule method showed a good agreement and relative standard deviations of triplicates were less than 5%. The poor reproducibility of the copper tube method appears to be attributed to the incomplete sealing in connection between faucets of wellhead and the sampling apparatus. The copper tube method also showed higher CFCs concentrations than the glass ampule method, which is more pronounced for CFC-11 than for CFC-12. The plastic tubings and rubber gasket of faucets in case of the copper tube method possibly contaminated the samples with CFC-11 and CFC-12. The potential of CFCs contamination for the glass ampule method was eliminated by using stainless steel and Nylon only and by connecting the sampling equipment directly to the main discharge pipe of wellhead. The validity of the glass ampule method were also verified by detecting very low level of CFCs for the ground-water sample which is old enough to have negligible CFCs.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.271-271
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• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• Earthquakes and Structures
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• v.9 no.4
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• pp.735-752
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• 2015

The effectiveness of seismic retrofitting of RC-frame buildings by converting selected bays into new walls through infilling with RC walls was studied experimentally using a full-scale four-storey model tested with the pseudo-dynamic (PsD) method. The frames were designed and detailed for gravity loads only using different connection details between the walls and the bounding frame. In order to simulate the experimental response, two numerical models were formulated differing at the level of modelling. The purpose of this paper is to illustrate the capabilities of these models to simulate the experimental nonlinear behaviour of the tested RC building strengthened with RC infill walls and comment on their effectiveness. The comparison between the capacity, in terms of peak ground acceleration, of the strengthened frame and the one of the bare frame, which was obtained numerically, has shown a five-fold increase.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.70-76
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• 2012

In general, the unidirectional power flow is normal in distribution feeders before activation of distributed power source such as PV. However, the interactive power flow is likely to occur in case of the power system under distributed generation. This interactive power flow can cause an unexpected effect on convectional protection coordination systems designed based only on the unidirectional power flow system. When the power line system encounters a problem, the interactive power flow can be a contributed current source and this makes the fault current bigger or smaller compared to the unidirectional case. The effect of interactive power flow is varied depending on the location of the point to ground fault, relative location of the PV, and connection method. Therefore it is important to analyse characteristics of fault current and interactive flow for various transformer connection and location of the PV. This paper proposes a method of improved protection coordination which can be adopted in the protective device for customers in distribution feeders interconnected with the PV. The proposed method is simulated and analysed using PSCAD/EMTDC under various conditions.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.74.1-74.1
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• 2011

To probe the connection between starburst and AGN activity, we investigate the relation between the 3.3 micron~PAH emission and AGN properties based on the new AKARI observations and the data collected from the literature. Using a sample of low-z Type I AGN, we measure the global 3.3 micron PAH luminosity from the AKARI slit-less spectroscopy. The 3.3 ${\backslash}$micron~PAH emissions are detected for 7 out of 26 target galaxies, but we find no strong correlation between the 3.3 ${\backslash}$micron~PAH emission and AGN luminosity, suggesting that global star formation may not be tightlyrelated with AGN activity. In contrast the to global star formation, the nuclear 3.3 micron~PAH emission luminosity, which are measured from ground-based long slit spectroscopy with a narrow slit, correlates with AGN luminosity. These results imply that starburst and AGN activity are directly connected at the nuclear region.