• International Journal of Railway
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• 제7권1호
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• pp.16-23
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• 2014

Reduction in railway-induced vibrations in urban areas is a very challenging task in railway transportation. Many mitigation measures can be considered and applied. Among these, a little attention has been paid to trenches. In this study, a numerical investigation on the effectiveness of in-filled trenches with pipes in reducing railway vibrations due to passing trains is presented. Particularly, a series of two-dimensional dynamic analysis was performed to model the behavior of ballasted railway track under harmonic load with ABAQUS software as a Finite Element method. In so doing, two types of in-filled trenches with pipes with steel and concrete materials have been investigated in this paper. In addition, effectiveness of pipes made of steel and concrete, filled with loose sand and clay in railway-induced vibration reduction has been assessed. The results point out that using in-filled trench with pipes does not effective a lot on railway-induced vibration reduction in comparison to other railway-induced vibration reduction methods. However, in-filled trenches with steel pipes are much more effective than in-filled trenches with concrete pipes. Moreover, filling pipes with loose sand and clay does not have any effect on vibration reduction efficiency of these in-filled trenches.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.100-108
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• 1999

rectangular open or in-filled trenches(concrete and rubber) are often used to reduce the ground vibrations caused by propagating surface(Rayleigh) waves. This paper presents the experimental data for estimating the vibration screening effectiveness of open or in-filled trenches Field dynamic tests using the exciter which can generate the 100kN vertical cyclic load in the range of 100-250 Hz were performed. One hundred and twenty accelerometers to measure the ground response are used in 6 radial direction. To compare the effectiveness of the vibration isolation the contours of the amplitude ratio with the dimensionless parameters dividing by Rayleight wave lengths were presented.

• Structural Engineering and Mechanics
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• 제11권5호
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• pp.503-518
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• 2001

In this paper, the procedure for deriving an infinite element that is compatible with the quadrilateral Q8 element is first summarized. Enhanced by a self mesh-expansion procedure for generating the impedance matrices of different frequencies for the region extending to infinity, the infinite element is used to simulate the far field of the soil-structure system. The structure considered here is of the box type and the soils are either homogeneous or resting on a bedrock. Using the finite/infinite element approach, a parametric study is conducted to investigate the effect of open and in-filled trenches in reducing the structural vibration caused by a train passing nearby, which is simulated as a harmonic line load. The key parameters that dominate the performance of wave barriers in reducing the structural vibrations are identified. The results presented herein serve as a useful guideline for the design of open and in-filled trenches concerning wave reduction.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.106-112
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• 1998

A numerical experiment is conduced to study the wave screening effectiveness of wave barriers which are constructed to reduce the ground-transmitted vibration. The finite element method is used for the simulation of the wave propagation behavior. In order to reduce the computational burden the absorbing boundary's one employed. Validity of the numerical model is checked by comparing the results with the published data. The screening effectiveness of the in filled trenches is then studied for different trench dimensions and material properties.

• 한국전기전자재료학회논문지
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• 제14권3호
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• pp.228-233
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• 2001

This paper presents the optimized design, fabrication and thermal characteristics of micro-heaters for thermal MEMS (micro elelctro mechanical system) applications usign SOI (Si-on-insulator) and trench structures. The micro-heater is based on a thermal measurement principle and contains for thermal isolation regions a 10㎛ thick Si membrane with oxide-filled trenches in the SOI membrane rim. The micro-heater was fabricated with Pt-RTD (resistance thermometer device) on the same substrate by suing MgO as medium layer. The thermal characteristics of the micro-heater wit the SOI membrane is 280$\^{C}$ at input power 0.9W; for the SOI membrane with 10 trenches, it is 580$\^{C}$ due to reduction of the external thermal loss. Therefore, the micro-heater with trenches in SOI membrane rim provides a powerful and versatile alternative technology for improving the performance of micro-thermal sensors and actuators.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.569-572
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• 2000

This paper presents the optimized fabrication and thermal characteristics of micro-heaters for thermal MEMS applications using a SDB SOI substrate. The micro-heater is based on a thermal measurement principle and contains for thermal isolation regions a 10$\mu\textrm{m}$ thick silicon membrane with oxide-filled trenches in the SOI membrane rim. The micro-heater was fabricated with Pt-RTD(Resistance Thermometer Device)on the same substrate by using MgO as medium layer. The thermal characteristics of the micro-heater with the SOI membrane is 280$^{\circ}C$ at input Power 0.9 W; for the SOI membrane with 10 trenches, it is 580$^{\circ}C$ due to reduction of the external thermal loss. Therefore, the micro-heater with trenches in SOI membrane rim provides a powerful and versatile alternative technology for improving the performance of micro thermal sensors and actuators.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.197-201
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• 2002

This paper presents optimized design, fabrication and thermal characteristics of micro-heaters for thermal MEMS (micro electro mechanical system) applications using SOI and trench structures. The micro-heaters are based on a thermal measurement principle and contains thermal isolation regions of 10 ${\mu}m$-thick Si membranes consisting of oxide-filled trenches in the SOI membrane rim. The micro-heaters were fabricated with Pt-RTD on the same substrate via MgO buff layer between Pt thin-film and $SiO_2$ layer. The thermal characteristics of micro-heater with trench-free SOI membrane structure was $280^{\circ}C$ at input power 0.9 W; in the presence of 10 trenches, it was $580^{\circ}C$ due to reduction of the external thermal loss. Therefore, a micro-heater with trenches in SOI membrane rim structure provides a powerful and versatile alternative technology for enhancing the performance of micro-thermal sensors and actuators.

• 한국지반공학회논문집
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• 제20권6호
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• pp.41-49
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• 2004

진동전달을 차단하는 공법으로는 방진구나 방진벽공법 등이 있으며 최근에는 다양한 재료를 사용한 차단벽공법 등이 제안되고 현장 시공도 다수 행해지고 있으며 또한 저감효과가 확인되고 있다. 그러나 이들 공법은 가진원의 특성, 지반조건, 차단벽의 매개변수 등이 복잡하여 합리적이고 정량적인 진동저감 평가방법이 아직 확립되어 있지 않다. 본 연구는 이러한 관점에서 지표면에 점가진이 전달될 경우 진동차단벽공법을 원심모형실험을 통하여 재현하고자 하였다. 이를 위해 차단벽재의 강성 및 차단벽재의 타설 심도를 변화시키는 실험을 실사하고 이들의 차이가 방진효과에 미치는 영향에 대하여 검토하였다. 본 연구결과 원심모형 실험장치를 환경진동 문제에 적용하고 파동의 지반내 전달현상 및 메카니즘을 파악하고 본 연구에서 개발한 충격 재하장치의 적용성을 확인했다.

• 한국진공학회지
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• 제11권4호
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• pp.235-239
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• 2002

식각된 트랜치의 내부에 다결정 실리콘 측벽을 형성하고, 감압 화학기상 증착법(RPCVD: Reduced Pressure Chemical Vapor Deposition)을 이용해서 이를 선택적으로 성장시킴으로써 트랜치를 채우는 새로운 트랜치 격리방법을 제안하였다. 공정진행 결과, 측벽의 초기깊이와 선택적으로 성장되는 실리콘의 두께가 트랜치의 최종형태를 결정하는 가장 중요한 요소임을 확인할 수 있었다. 이 방법은 CMP 공정을 거치지 않고도 트랜치의 내부만이 실리콘으로 채워진 구조를 구현함으로써, 공정을 단순화할 뿐만 아니라 불균일 연마와 흠집발생 등 기존의 CMP 공정에서 발생할 수 있는 문제들을 방지할 수 있다는 장점을 지니고 있다.

• 한국의사학회지
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• 제34권1호
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• pp.31-46
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• 2021

Shin Hong-Gyun and his family have been in medicine for many generations as Korean Medical Doctors (KMDs). In 1919 when Shin Hong-Gyun was participating in an independence movement in Jang-Baek-Hyun, his younger brother Shin Dong-Gyun was killed by Japanese military police forces. This tragic incident triggered Shin Hong-Gyun to establish an army for national independence called , holding 200 young men, to serve in armed struggle against the Japanese Government with Kim Jung-Geon in May, 1920. In March 1933, Shin Hong-Gyun, as a military surgeon, led his men to the Korean Independence Army to fight a battle. Once he became a member of the Korean Independence Army, he, in fact, participated in few battles: Sadohaja, Dong-Kyung-Sung, Deajeonjayeong. Daejeonjayeong was a waypoint that the Japanese military needed to pass through in order to reach the Wangcheong area. Shin Hong-Gyun's independence forces had to endure painful starvation and heavy rain while hiding in ambush for long periods of time until the Japanese military would appear. Due to its summer rainy season, rainwater overflowed into their trenches and was filled up to the waist. Even worse, food stockpiles were low and the Japanese army did not appear for longer time. Shin Hong-Gyun's entire team suffered severe hunger and extreme cold. At this critical moment, Shin Hong-Gyun used his expertise as a KMD to find edible black mushrooms that grow wild in the mountains and use them to feed his men. This event led to the victory of the independence army at the battle of Daejeonjayeong. The purpose of the paper is to inform and highlight the forgotten history of Shin Hong-Gyun who was, both, a Korean Medical Doctor and a military surgeon.