• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.3
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• pp.141-150
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• 2014

A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolated nuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system to demonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes but also the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which were matched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of piping system. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismically isolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stress response of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the design level earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to the intensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verification of the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should be evaluated firstly.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.680-687
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• 2009

In this paper, we propose a substrate integrated waveguide(SIW) power divider to yield excellent broadband isolation performance. In order to achieve high broadband isolation, a two stage Wilkinson power divider is employed in SIW. The measurement results show the insertion loss($S_{21}$, $S_{31}$ to be $4.0{\pm}0.5$ dB) and input return loss($S_{11}$ of 10 dB) from 13.12 GHz to 16.14 GHz. Moreover, the results show that the output return loss and isolation between output ports are larger than 10 dB between 10.37 GHz and 17.64 GHz.

• Computers and Concrete
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• v.21 no.5
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• pp.495-504
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• 2018

The possibility of earthquakes in vulnerable regions indicates that efficient technique is required for seismic protection of buildings. During the recent decades, the concept is moving towards the insertion of base isolation on seismic prone buildings. So, investigation of structural behavior is a burning topic for buildings to be isolated in base level by bearing device. This study deals with the incorporation of base isolation system and focuses the changes of structural responses for different types of Lead Rubber Bearing (LRB) isolators. A number of sixteen model buildings have been simulated selecting twelve types of bearing systems as well as conventional fixed-base (FB) scheme. The superstructures of the high-rise buildings are represented by finite element assemblage adopting multi-degree of freedoms. Static and dynamic analyses are carried out for FB and base isolated (BI) buildings. The dynamic analysis in finite element package has been performed by the nonlinear time history analysis (THA) based on the site-specific seismic excitation and compared employing eminent earthquakes. The influence of the model type and the alteration in superstructure behavior of the isolated buildings have been duly assessed. The results of the 3D multistory structures show that the lateral forces, displacement, inertia and story accelerations of the superstructure of the seismic prone buildings are significantly reduced due to bearing insertion. The nonlinear dynamic analysis shows 12 to 40% lessening in base shear when LRB is incorporated leading to substantial allowance of horizontal displacement. It is revealed that the LRB isolators might be potential options to diminish the respective floor accelerations, inertia, displacements and base shear whatever the condition coincides. The isolators with lower force intercept but higher isolation period is found to be better for decreasing base shear, floor acceleration and inertia force leading to reduction of structural and non-structural damage. However, LRB with lower isolator period seems to be more effective in dropping displacement at bearing interface aimed at reducing horizontal shift of building structure.

• The Korean Journal of Mycology
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• v.13 no.1
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• pp.1-10
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• 1985

This experiment was undertaken to investigate proper conditions for protoplast isolation from strains of Agaricus bisporus, Flammulina velutipes, Lentinus edodes, Pleurotus florida, Pleurotus ostreatus, Pleurotus sajor-caju and Volvariella volvacea. Combination of ${\beta}-D-glucanase$, novozym 234 and snail enzyme with 0.6M $MgSO_4$ in 0.05M Na-maleate buffer, pH 5.8 was the most effective for isolation of protoplasts. High yields of protoplasts were obtained from $4{\sim}5$ days old mycelia of P. florida and P. ostreatus on mushroom complete agar medium. Protoplasts were also obtained in good yield from other fungi but A. bisporus and V. volvacea. In the latter two cases protoplast release was observed; however, the yield was much lower than those of the other fungi.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.563-570
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• 2004

Phased isolation intrachannel clarifier ditch process developed in this study is an enhanced biological nutrient removal process employing two ditches with intrachannel clarifiers. Bench-scale phased isolation ditch process was used to evaluate the system performance on municipal wastewater and detailed assessment of internal behavior in a ditch and each reactions. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31 days, and cycle times of 4hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 73~78%, and 65~90%, respectively. The internal behavior were well matched on each reactions such as nitrification, denitrification, and phosphorus release and uptake. As the SRT became longer, TN removal increased gradually, whereas TP removal decreased contrarily. However, the system was capable of producing an effluent TP concentration 1mg/L or less even at longer SRTs except the case of solids discharge by malfunction of intra-clarifier occurred by its geometrical limit. The system performance slightly decreased by hydraulic shock loading(increasing of influent flowrate and decreasing of system HRT). However, the higher system performance could be achieved again after four cycles. Thus, the system reliability could be successfully achieved short-term hydraulic shock loading that occurred in medium- and small-sized wastewater treatment plants suffering fluctuation of influent quality and flowrate during wet season.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.15-32
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• 2007

The purposes of this study are carrying out the case study for the urban park planning in point of landscape ecology, analyzing and evaluating the indicator character of the landscape ecological view on the basis of the case study, and proposing the urban park planning in point of landscape ecology. The results of this study are as follows. As a result of the isolation analysis with school green space, Kyukchaebosang Park turned out to be 607m, Chimsan Park to be the highest 647.14m, Ehyeun Park to be the lowest 592m. In the case of connection analysis with all nodes, Kyukchaebosang Park had the lowest score 0.27 and Chimsan Park had the highest score 1. As a result of the circulation analysis with elementary schools, Kyukchaebosang Park and Ehyeun Park got 1 within 500m permissible range, and Chimsan Park got over 1, Ehyeun Park got 0.67, and Kyukchaebosang Park got 0.14 respectively within 700m permissible range. According to these analysis results, special regions which has problems such as high isolation and low connection and circulation in point of landscape ecology can be selected. Also by changing them to valuable green spaces, urban park planning can be improved. In this study, the basic data of landscape ecology can be obtained by the character analysis of landscape ecology. This study has a significant meaning of possibility in planning of the urban park which reflects the character of landscape ecology. This research was only performed in Chimsan Park, so additional researches for various cases will be needed.

• Human Ecology Research
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• v.51 no.4
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• pp.395-401
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• 2013

The purpose of this study is to investigate the moderating effects of language abilities associated with between emotionality, attention deficit hyperactivity disorder (ADHD) and peer play interactions. Two hundred fifty-two participants were 3 year olds, with 136 boys and 116 girls. They were recruited from day care centers and preschools in Gyunggi province and Incheon city. Peer play interaction was assessed by the Penn Interactive Peer Play Scale (PIPPS). Emotionality was measured by Child Behavior Questionnaire (CBQ). ADHD was assessed by teacher ratings of ADHD syndrome. Language abilities were measured by Korean Wechsler Preschool and Primary Scale of Intelligence (K-WPPSI). Teachers completed questionnaires to assess peer play interactions, emotionality, ADHD. The results revealed that language abilities moderated relationships between emotionality and play in isolation. The magnitude of associations between emotionality and play in isolation was greater for high levels of language abilities. Moreover, there were moderating effects of language abilities associated between ADHD and play disruptions. Although ADHD was significantly associated with play disruptions, the association was stronger at the higher levels than the low levels of language abilities. It can be deduced that language abilities of 3 year old children affects the protection factor between emotionality and peer play isolation; whilst, it affects the risk factor on peer play disruptions and ADHD propensity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.415-422
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• 2004

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz down-conversion mixer for DSRC communication system was designed and fabricated using 0.8 ${\mu}{\textrm}{m}$ SiGe HBT process technology and RF/LO matching circuits, RF/LO input balun circuits, and If output balun circuit were all integrated on chip. The chip size of fabricated mixer was 1.9 mm${\times}$1.3 mm and the measured performance was 7.5 ㏈ conversion gain, －2.5 ㏈m input IP3, 46 ㏈ LO to RF isolation, 56 ㏈ LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.350-357
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• 2005

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz up-conversion mixer for DSRC communication system was designed and fabricated using 0.8 m SiGe HBT process technology and IF/LO/RF matching circuits, IF/LO input balun circuits, and RP output balun circuit were all integrated on chip. The chip size of fabricated mixer was $2.7mm\times1.6mm$ and the measured performance was 3.5 dB conversion gain, -12.5 dBm output IP3, 42 dB LO to If isolation, 38 dB LO to RF isolation, current consumption of 29 mA for 3.0 V supply voltage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.3
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• pp.307-313
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• 2009

In general, pyroshock is generated from the actuation of separation devices for several stage, fairing, and satellite separation in the flight of a launch vehicle. During these events, transient vibration phenomenon called pyroshock, which shows large acceleration in the high frequency range, occurs and it can result in the malfunction of electronic components which is equipped inside the launch vehicle or satellite. In this paper, mesh washer isolators made out of SMA were introduced for the isolation of pyroshock. One type of isolator primarily used pseudoelastic characteristics of SMA and the other type of isolator used shape memory effect of SMA. For the study of basic load-displacement relationship of each SMA isolator, compressive loading tests were performed and the results showed the capability of the isolator itself. Pyroshock isolation tests were followed and verified the outstanding isolation performance of isolator. In addition, random vibration tests were also performed and checked the dynamic characteristics of each SMA isolator.