• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.179-179
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• 2011

이동의 편리함과 주행안정성을 주기 위해 개발된 도로가 소음을 발생시켜 운전자 및 소비자의 쾌적성을 저해하는 요소로 작용하고 있다. 이러한 문제를 해결하기 위해 연도거리확보 또는 방음벽 등의 소음억제 방법을 사용하고 있으나 미관을 저해하고 용지사용이 비효율적이어서 외국의 경우 저소음 포장 연구를 통한 근본적은 소음 발생원을 차단하기 위한 노력이 진행되고 있다. 국내에서도 신도시 개발 등으로 도로건설에 따른 급속한 교통량 증가 및 차량의 고속주행으로 인하여 도시소음의 주요인으로 부각되고 있고 시민들의 높은 생활수준과 소음 환경에 대한 기본생활권 추구 성향이 증대되어 지역 주민의 교통소음 저감 대책 및 보상에 대한 법적 소송이 빈번히 발생하고 있어 차량 주행 소음 저감을 위한 방법으로 방음벽 설치가 널리 사용되고 있으나 이는 경제적 손실뿐만 아니라 도시미관을 해치는 문제가 발생하고 있다. 도로사업의 환경성 강화는 국토해양부의 2009년 주요도로정책 중 하나일 정도로 국가정책의 중요한 지침으로써, 향후 추진되는 신도시 및 단지조성공사 시 도로 환경성과 소음, 진동, 그리고 생태통로에 대한 친환경 도로설계 및 시공 등에 적절히 대응하기 위하여 교통소음을 개선하기 위해서는 교통소음 발생 요소를 파악하고 신도시 및 단지조성시 주변도로에 친환경적 포장공법 설계기술의 개발 및 적용을 위한 단계적 연구가 필요하다. 따라서 본 연구에서는 친환경 저소음 포장공법의 종류에 대하여 알아보고자 한다.

• Journal of the Korean Chemical Society
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• v.27 no.1
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• pp.9-17
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• 1983

The effect of pressures and temperatures on the stabilities of the durene-iodine charge transfer complex have been investigated through ultraviolet spectrophotometric measurements in n-hexane. The stabilities of complexes were measured at 25, 40 and $60^{\circ}C$ under $1{\sim}1600$ bars. The equilibrium constant of the complex was increased with pressure and decreased with temperature raising. The absorption coefficient was increased with both pressure and temperature. Changes of volume, enthalpy, free energy and entropy for the formation of complexes were obtained from the equilibrium constants. The red-shift observed at a higher pressure, the blue-shift at a higher temperature, and the relation between pressure and oscillator strength were discussed by means of thermodynamic functions.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.581-589
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• 2004

This paper describes the amount of food consumption and the change of total weight of abalone under a vibration with noise that can be occurred due to piling work. This experiment was conducted in the aquarium in Yosu National University. In normal situation the juvenile stage shell's(total length is 1～1.5cm) amount of food consumption was 0.81g, the middle stage shell(total length is 3～3.5cm) was 13.61g, and the adult stage shell (Total length is 7～7.5cm) was 43.l9g per 5 organisms in 24 hours, while the experimental group was observed low numerical value compared normal groups. The abalones' food consumption and total weight in both groups, the intermittent and continuance impact with noise and vibration, was reduced during this experiment. The abalones' food consumption and total weight in the experimental groups without vibration were recorded slightly high numerical value than the experimental groups with noise and vibration. Based on this experimental data we could conjecture the noise and vibration are harmful factors to bring up a physiological stress to abalones. Especially, the vibration impact by piling works could produce a considerably unfavorable effect to the abalones than noise impact.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.99-104
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• 2015

As riders do not sense damage to hub bearings due to the friction that occurs while riding, unexpected accidents can happen. Hub bearings can also be broken by cracks due to minor impact. Therefore, the vibration analysis of bike hub bearings is thought to be important. Two bike hub bearings were modelled in this study. The bolts at both ends of the bearings were fixed. The standard weight of a Korean man was assumed to be 70Kg, and a force of 700N was applied. As a result of this study, maximum deformations occurred in bolts at both ends of the central axis. Regarding displacement due to natural frequencies, Model 2 had less deformation than Model 1. Using the results of this study, the structural safety of the design of hub bearings can be estimated, and design plans for durable hub bearings can be suggested.

• Journal of the Korean Institute of Navigation
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• v.25 no.1
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• pp.45-52
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• 2001

The purpose of this study is the optimum modification of dynamic characteristics of stiffened plate structure. In the method of the optimization, finite element method(FEM), sensitivity analysis and optimum structural modification method are used. To begin with, using FEM, the dynamic characteristics of stiffened plate structure is analyzed. Next, rate of change of dynamic characteristics by the change of design variable is calculated using the sensitivity analysis. Then, amount of change of design variable is calculated using this sensitivity value and optimum structural modification method. The change of natural frequency is made to be an objective function. Thickness of plate and cross section moment become a design variable. It is shown that the results are effective in the optimum modification for dynamic characteristics of the stiffened plate structure.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.916-921
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• 2003

In most industrial applications, the geometrical complexity is combined with the moving boundaries. These problems considerably increase the computational difficulties since they require, respectively, regeneration and deformation of the grid. As a result, engineering flow simulation is restricted. In order to solve this kind of problems the immersed boundary method was developed. In this study, the immersed boundary method is applied to the numerical simulation of stationary, rotating and oscillating cylinders in the 2-dimensional square cavity. No-slip velocity boundary conditions are given by imposing feedback forcing term to the momentum equation. Besides, this technique is used with a second-order accurate interpolation scheme in order to improve the accuracy of flow near the immersed boundaries. The governing equations for the mass and momentum using the immersed boundary method are discretized on the non-staggered grid by using the finite volume method(FVM). This study presents the possibility of the immersed boundary method to apply to the complex flow experienced in the industrial applications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1265-1272
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• 2011

We performed numerical simulations of the recirculation flow of an electrolyte fluid in a circular container driven by an AC electromagnetic force for solving continuity and momentum equations. We also conducted an experiment to obtain flow data, which were in good agreement with the numerical simulation results. Furthermore, we performed a parametric study on both numerical and experimental aspects and found that the fluid velocity increases with an increase in the electrolyte concentration and magnetic intensity and with a decrease in the fluid depth and AC frequency.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.223-225
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• 2008

하이드레이트는 저온.고압에서 저분자량의 게스트(guest)가 호스트(host)인 물분자 속에 포획되어 만들어지는데 일련의 과정은 물리적 반응을 통해 생성된다.본 연구에서는$CO_2$보다 지구온난화지수(Global Warming Potential)가 23,900배 높은 $SF_6$의 회수 및 정제기술로써 하이드레이트화를 이용하는 신기술 개발의 일환으로 분광학적 접근을 통해 $SF_6$ 혼합 하이드레이트의 정성 및 정량분석을 수행하였다. Raman Shift 분석 결과 $SF_6$의 $770cm^{-1}$에서 $v_1$ 진동주파수를 확인함으로써 하이드레이트 내 $SF_6$가 안정적으로 포집됨을 확인하였고 혼합가스 내 $SF_6$ 농도별로 만들어진 샘플의 Raman Shift를 통해서 $SF_6$의 하이드레이트 전환율을 가늠할 수 있었다.

• Water for future
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• v.27 no.1
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• pp.53-67
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• 1994

Water quality analysis in the midstream of the Nakdong river is studied. Deterministic model RQ1 which contains two code, RQ1-1 for hydrologic and hydraulic analysis and RQ1-2 for water quality analysis are developed. Monthly mean and minimum discharges in the basin (from Waegwan to Jindong) are estimated. A varied flow analysis is performed based on the geometric data of channel and RQ-1 model. The maximum concentration of BOD and minimum concentration of DO are occurred at the confluence of Keumho river and immediately downstream of Hyunpoong, respectively. The computed concentrations of BOD at several points have good agreements with observed data. Maximum allowable BOD loads from the Keumho River are provided to attain the goal of water quality in the basin.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.223-223
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• 2012

최근 선진국의 산업구조는 반도체, 디스플레이, IT 제품 등 고부가가치 산업으로 재편되고 있으며, 이에 따라 핵심 공정장비인 고진공펌프의 수요가 급격히 증대하고 있다. 고용량/대면적/초정밀 제품을 지향하는 개발추세에 따라 핵심 공정 장비로서 크라이오펌프의 활용도가 크게 증가하며 LCD 분야 등과 같이 수소 분자와 물 분자 등의 배기가 중요한 응용분야에 크라이오펌프의 수요가 대부분을 차지하고 있다. 또한 도래하는 한미FTA 체결에 따라 반도체, IT, 디스플레이 제조 장비용 고진공펌프의 수입이 급증할 것으로 예상되어 국내 진공업체에서도 크라이오 펌프의 개발이 진행되고 있다. 국내에서는 크라이오펌프 뿐만 아니라 핵심부품인 극저온 냉동기에 대한 기반 기술이 낙후되어 있는 실정이다. 본 연구에서는 지식경제부 지원 사업인 제조기반산업원천기술개발사업에 참여기관으로 수행하여 한국기계연구원과 급속 재생형 저진동 크라이오펌프의 기술 개발을 통해 전량 수입하는 고진공 펌프인 크라이오펌프를 국산화를 도모하고자 한다. 또한, 맥동관 냉동기는 기계적 구동부가 없어 구조가 간단하여 운전이나 보수가 용이하고, 장시간 운전에 신뢰성이 높으며 제조비용이 저렴하다. 이에 (유)우성진공에서는 연구 개발을 통해 상용화 단계에 있는 맥동관 냉동기 크라이오펌프를 소개하고자 한다.