• Journal of the Korean Society for Precision Engineering
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• v.25 no.10
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• pp.107-114
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• 2008

The aim of this study is to obtain the useful design guideline for high impulsive force device with an isolation system by the analytic approach of dynamics characteristics. In this study, the high impulsive force system was modeled and analyzed in view of multi-body dynamics, and verified the modeling and analysis result by the experiment of the high impulsive force device. Additionally, the dynamic analysis was performed for the isolation system with the selected coefficients of elastic spring and damper selected. Experimental result for the high impulsive force device with the isolation system was compared and analyzed. From the result, it was confirmed that the design guideline for the isolation system of the high impulsive force device was useful.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1227-1232
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• 2011

Using the notch and isolation, we investigated the insertion loss and isolation characterics of the fabricated dielectric duplexers and bandpass filters for CDMA and W-CDMA dualband. Insertion loss(Tx band) and isolation(between Tx and Rx) of duplxer were about -2.1708dB and 45dB at CDMA band, respectively. Also, in the case of W-CDMA, the insertion loss(Tx band) and isolation(between Tx and Rx) showed about -2.6946 and 100dB, respectively. Summering the aboved results, fabricated the dielectric duplexers and bandpass filters will be contributed the increase of atttenuation and the decrease of interference at CDMA and W-CDMA dualband.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.167-173
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• 2005

The isolation of the series PIN diode switch is restricted by the parallel capacitance of PIN diode and the switch driver circuit limits switching speed of PIN diode switch. To overcome these problems, a high isolation and high switching speed Pin diode switch is proposed adapting the parallel resonant inductance and TTL compatible switch driver circuit. The measurement results of the 3 GHz PM diode switch show 1 GHz frequency band, less than 1.5 dB insertion loss, 65 dB isolation, more than 15 dB return loss and less than 30 ns switching speed. In particular the 3 GHz PIN diode switch using the parallel resonant inductance exhibits the improvement of isolation by 15 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.147-147
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• 1993

All types of dynamic excitation, periodical, pulse or transient in vertical, horizontal or all three directions can be effectively reduced by vibration isolation systems. Typical elements for vibration isolation control are spring units consisting of a group of helical compression springs. In all cases of shock, transient or random excitation energy absorbing dampers have to be added to the spring units in order to reduce system response in the frequency range near the natural frequency of the isolation system. The same isolation system of spring units and viscos-dampers has been used since 1979 for passive protection of buildings and structures has been proved to by very advantageous for vibration and structure borne noise control. Not only because of high vertical flexibility of the spring units, compared for example with typical rubber or neoprene mounts out also because of the horizontal of flexibility, which can be adapted by modifying the spring dimensions to nearly every requirement. It is just normal to use the same basic elements for passive isolation as for active isolation.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1223-1240
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• 2014

Seismic isolation has been established as an effective earthquake-resistant design method and the lead rubber bearings (LRBs) are among the most commonly used seismic isolation systems. In the scientific literature, a sharp bilinear model is often used for capturing the hysteretic behaviour of the LRBs in the analysis of seismically isolated structures, although the actual behaviour of the LRBs can be more accurately represented utilizing smoothed plasticity, as captured by the Bouc-Wen model. Discrepancies between these two models are quantified in terms of the computed peak relative displacements at the isolation level, as well as the peak inter-storey deflections and the absolute top-floor accelerations, for the case of base-isolated buildings modelled as multi degree-of-freedom systems. Numerical simulations under pulse-like ground motions have been performed to assess the effect of non-linear parameters of the seismic isolation system and characteristics of both the superstructure and the earthquake excitation, on the accuracy of the computed peak structural responses. Through parametric analyses, this paper assesses potential inaccuracies of the computed peak seismic response when the sharp bilinear model is employed for modelling the LRBs instead of the more accurate and smoother Bouc-Wen model.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1141-1169
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• 2014

This study is aimed to investigate the seismic performance of low-rise precast wall system with base isolation. Three types of High Damping Rubber Bearing (HDRB) were designed to provide effective isolation period of 2.5 s for three different kinds of structure in terms of vertical loading. The real size HDRB was manufactured and tested to obtain the characteristic stiffness as well as damping ratio. In the vertical stiffness test, it was revealed that the HDRB was not an ideal selection to be used in isolating lightweight structure. Time history analysis using 33 real earthquake records classified with respective peak ground acceleration-to-velocity (a/v) ratio was performed for the remaining two types of HDRB with relatively higher vertical loading. HDRB was observed to show significant reduction in terms of base shear and floor acceleration demand in ground excitations having a/v ratio above $0.5g/ms^{-1}$, very much lower than the current classification of $0.8g/ms^{-1}$. In addition, this study also revealed that increasing the damping ratio of base isolation system did not guarantee better seismic performance particularly in isolation of lightweight structure or when the ground excitation was having lower a/v ratio.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.188-195
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• 2017

Biotech crops can only be commercialized after they receive safety approvals, which require thorough risk assessments of their release to the environment. Environmental release experiments are indispensable for environmental risk assessments, and each country has been preparing its own regulations for the safety management of experiments on the environmental release of biotech crops in confined fields. In this study, we compared and analyzed the safety management regulations of the environmental release of biotech crops in Korea, USA, Japan, European Union, and China. Each country had safety management regulations for the environmental release of biotech crops, and these regulations were generally not much different from the Korean regulations. However, there was a difference amongst the USA, Japan, and China in regulations for isolation distances to prevent gene diffusion through pollen-flow during environmental release experiments of biotech crops. In order to establish the isolation distance regulation suitable for the Korean environment, relevant data were collected and presented. For setting the isolation distance for environment release of biotech crops, it is suggested to refer to the isolation distance information provided in the Guidance of Seed Management in Korea. The results of this study are expected to help establish the safety management of biotech crops in Korea.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.168-175
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• 2001

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do net quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

• Asian Oncology Nursing
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• v.9 no.1
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• pp.31-42
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• 2009

Purpose: The purpose of the study was to understand how patients experience everyday life in an isolation unit for hematopoietic stem cell transplantation (HSCT). Method: The data were collected from 25 patients with HSCT at the isolation unit from January to March in 2008 in one general hospital in Korea. The data were collected by participant observations and ethnographic interviews and were analyzed using ethnographic method. Results: Four themes regarding environmental area emerged: 'barrier pulling up the drawbridge', 'very strange world', 'small and restricted space tied by IV and other treatment lines', and 'loud noise in a silent space.' Three themes regarding patients emerged: 'facing fear and anxiety', 'continuation of loneliness and lethargy', and 'compromising with a very long, dull, and boring time'. These themes describe how patients with HSCT suffer from continuous physical and psychosocial problems in a confined space, while endeavoring to control these problems and to search for hope for a new life. Conclusion: The results of the study provide an in-depth understanding of the experience and culture of patients in an isolation unit for HSCT. They would be used in developing practical programs to decrease patient's culture shock including fear and anxiety at isolation unit for HSCT.

• Journal of Korean Association for Spatial Structures
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• v.18 no.3
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• pp.105-116
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• 2018

The objective of this study is to investigate the response reducing effect of a seismic isolation system installed between 300m dome and supports under both horizontal and vertical seismic ground motion. The time history analysis is performed to investigate the dynamic behavior of single layer lattice domes with and without a lead rubber bearing seismic isolation system. In order to ensure the seismic performance of lattice domes against strong earthquakes, it is important to investigate the mechanical characteristics of dynamic response. Horizontal and vertical seismic ground motions cause a large asymmetric vertical response of large span domes. One of the most effective methods to reduce the dynamic response is to install a seismic isolation system for observing seismic ground motion at the base of the dome. This paper discusses the dynamic response characteristics of 300m single layer lattice domes supported on a lead rubber seismic isolation device under horizontal and vertical seismic ground motions.