• Title/Summary/Keyword: unusual phenomenon

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An Experimental and Analytical study on the Steel Plate Girder Railway bridge in the applying External Post-tensioning Method (강철도교에 대한 외부 후긴장 보강공법의 적용에 관한 실험 및 해석적 연구)

  • Park, Young-Hoon;Cho, Sun-Kyu;Choi, Jung-Youl;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.9 no.2 s.33
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    • pp.151-159
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    • 2006
  • It analyzed the mechanical behaviors of non-ballasted railway bridge (steel plate girder type) with ballast reinforced on the finite element analysis, field test and laboratory test far the static and dynamic responses. The major objective of this study is to investigate the effects and application of reinforcement for steel plate girder railway bridge by the external post-tensioning method. The reinforcement of non-ballast railway bridge had obviously stable dynamic behaviors due to the additional dead force which was ballast. But in case of static behaviors, static displacements and stresses had increased nearly the allowable values. Therefore we analyzed the mechanical behaviors of non-ballasted railway bridge with ballast reinforced and external post-tensioning reinforced on the finite element analysis and laboratory test for the static and dynamic behavior. As a result, the reinforcement of ballasted railway bridge the external post-tensioning method are obviously effective for the additional dead force which is ballast. The analytical and experimental study are carried out to investigate the post-tension force decrease bending behavior and deflection in composite bridge for serviceability. The servicing railway bridge with ballast reinforced has need of the reasonable reinforcement measures which could be reducing the effect of additional dead load that degradation phenomenon of structure by an unusual. stresses and a drop durability.

A Study on Dynamic Behaviors of Steel Plate Girder bridge with Applying External Post-Tensioning Method (외부 후긴장 공법 적용에 따른 무도상 판형교의 동적거동 분석)

  • Choi, Dong-Ho;Choi, Jung-Youl;Choi, Jun-Hyeok;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.9 no.2 s.33
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    • pp.160-168
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    • 2006
  • The major objective of this study is to investigate the effects and application of external post-tensioning method far steel plate girder bridge. It analyzed the mechanical behaviors of steel plate girder bridge with applying external post-tensioning on the finite element analysis, field test and laboratory test fur the lateral dynamic characteristics. As a result, the reinforcement of steel plate girder bridge the external post-tensioning method are obviously effective for the lateral dynamic response which is non-reinforced. The analytical and experimental study are carried out to investigate the post-tension force decrease lateral acceleration and deflection on steel plate girder bridge for serviceability. And the external post-tensioning method reduce dynamic maximum displacement(about $10{\sim}24%$), the increase of dynamic safety is predicted by adopting external post-tensioning method. From the dynamic test results of the servicing steel plate girder bridge, it is investigated that the change degree of natural frequency is very low with applying the external post-tensioning method The servicing steel plate girder bridge with external post-tensioning has need of the reasonable reinforcement measures which could be reducing the effect of lateral dynamic behavior that degradation phenomenon of structure by an unusual response characteristic and a drop durability.

SIEVING NONLINEAR INTERNAL WAVES IN SATELLITE IMAGES

  • Liu, Cho-Teng;Chao, Yen-Hsiang;Hsu, Ming-Kuang;Chen, Hsien-Wen
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.820-823
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    • 2006
  • Nonlinear internal waves (NLIW) were studied as a unusual phenomena in the ocean decades ago. As the quality, quantity and variety of satellite images improve over decades, it is founded that NLIW is a ubiquitous phenomenon. Over the continental shelf of northern South China Sea (SCS), both optical and microwave images show that there are trains of NLIW packets near Dongsha Atoll (20.7N, 116.8E). Each packet contains several NLIW fronts. These NLIW packets are nearly parallel to each other and they are refracted, reflected or diffracted by the change of ocean bottom topography. Based on Korteweg de Vries (KdV) theory and the assumption that the bright/dark lines in the satellite images are centers of convergence/divergence of NLIW fronts, one may (1) sort NLIW packets in the same satellite image into groups of the same source, but generated at different tidal cycles, (2) relate NLIW packets in consecutive satellite images of one day apart, (3) locating faint signals of NLIW fronts in a satellite image. The NLIWs travel more than 100 km/day near Dongsha Atoll, with higher speed in deeper water. The bias and standard deviation of predicted location of NLIW front from its true location is about 1% and 5.1%, respectively.

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New Mechanism of Thin Film Growth by Charged Clusters

  • Hwang, Nong-Moon;Kim, Doh-Yeon
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1999.06a
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    • pp.115-127
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    • 1999
  • The charged clusters or particles, which contain hundreds to thousands of atoms or even more, are suggested to form in the gas phase in the thin film processes such as CVD, thermal evaporation, laser ablation, and flame deposition. All of these processes are also used in the gas phase synthesis of the nanoparticles. Ion-induced or photo-induced nucleation is the main mechanism for the formation of these nanoclusters or nanoparticles inthe gas phase. Charged clusters can make a dense film because of its self-organizing characteristics while neutral ones make a porous skeletal structure because of its Brownian coagulation. The charged cluster model can successfully explain the unusual phenomenon of simultaneous deposition and etching taking place in diamond and silicon CVD processes. It also provides a new interpretation on the selective deposition on a conducting material in the CVDd process. The epitaxial sticking of the charged clusters on the growing surface is gettign difficult as the cluster size increases, resulting in the nanostructure such as cauliflowr or granular structures.

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A Behavior Analysis of Railway Steel Plate Girder Bridge in the Applying Resilient Panel Track System (방진제도시스템 적용에 따른 강철도 무도상 판형교의 거동 분석)

  • Choi, Jung-Youl;Eom, Mac;Kang, Duk-Man;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.9 no.6 s.37
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    • pp.717-724
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    • 2006
  • The major objective of this study is to investigate the effects and application of improvement for railway steel plate girder bridge by resilient panel track system. It analyzed the mechanical behaviors of steel plate girder bridge with applying resilient panel track system on the finite element analysis and laboratory test for static & dynamic characteristics. As a result, the improvement of steel plate girder bridge with resilient panel track systems are obviously effective for the static & dynamic response which is non-ballast steel plate girder bridge. The analytical and experimental study are carried out to investigate resilient panel track system decrease vertical acceleration and deflection on steel plate girder bridge for serviceability. And the resilient panel track system reduced dynamic maximum displacements (about 59%) and stresses (about 82%), the increase of dynamic safety is predicted by adopting resilient panel track system. From the dynamic test results of steel plate girder bridge, it is investigated that vertical acceleration and deflection is very low with applying resilient panel track system. The servicing steel plate girder bridge with resilient panel track system has need of the reasonable improvement measures which could be reducing the effect of static and dynamic behavior that degradation phenomenon of structure by an unusual response characteristic and a drop durability.

A Behavior Analysis of HSR concrete slab track under Variety of Rail pad stiffness on fatigue effect (피로효과를 고려한 레일패드 스프링계수 변화에 따른 콘크리트 슬래브 궤도의 거동분석)

  • Eom, Mac;Choi, Jung-Youl;Chun, Dae-Sung;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.340-350
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    • 2007
  • The major objective of this study is to investigate the fatigue effects of rail pad on High Speed Railway with concrete slab track system. It analyzed the mechanical behaviors of HSR concrete slab track with applying rail pad stiffness based on fatigue effect(hardening and increasing stiffness) on the 3-dimensional FE analysis and laboratory test for static & dynamic characteristics. As a result, the hardening of rail pad due to fatigue loading condition are negative effect for the static & dynamic response of concrete slab track which is before act on fatigue effect. The analytical and experimental study are carried out to investigate rail pad on fatigue effected increase vertical acceleration and stress and decrease suitable deflection on slab track. And rail pad based on fatigue effect induced dynamic maximum stresses, the increase of damage of slab track is predicted by adopting fatigue effected rail pad. after due consideration The servicing HSR concrete slab track with resilient track system has need of the reasonable determination after due consideration fatigue effect of rail pad stiffness which could be reducing the effect of static and dynamic behavior that degradation phenomenon of structure by an unusual response characteristic and a drop durability.

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White Hanbok as an Expression of Resistance in Modern Korea

  • Seo, Bong-Ha
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.1
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    • pp.121-132
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    • 2015
  • All aspects of clothing, including color, are a visible form of expression that carries invisible value. The purpose of this work is to study the expression of resistance in the white Hanbok in modern culture, specifically after the 1980s. Koreans have traditionally revered white color and enjoyed wearing white clothes. In Korea, white represents simplicity, asceticism, sadness, resistance against corruption, and the pursuit of innocence. This paper looks at: (i) the universal and traditional values of the color white, (ii) the significance of traditional white Korean clothing, (iii) the resistance characteristics of white in traditional Korean clothes, and (iv) the aesthetic values of white Hanbok. The white Hanbok often connotes resistance when it is worn in modern Korea. It is worn in folk plays, worn by shamans as a shamanist costume, worn by protestors for anti-establishment movements, and worn by social activists or progressive politicians. The fact that the white Hanbok has lost its position as an everyday dress in South Korea (instead symbolizing resistance when it is worn) is an unusual phenomenon. It shows that the white Hanbok, as a type of costume, is being used as a strong means of expression, following a change in the value of traditional costumes as it take on an expressive function.

Effect of watershed characteristics on the criteria of Flash Flood warning (유역인자의 특성이 경계경보발령 기준에 미치는 영향분석)

  • 양인태;김재철;김태환
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2004.11a
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    • pp.389-392
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    • 2004
  • A recent unusual change in the weather is formed as a localized heavy rain in a short time. This phenomenon has caused a flash flood, and flash floods extensively have damaged human lives many times. In large river's case, the extent of loss of lives and properties has been decreased through the flood warning system by flood control stations of each stream. However, the extent of damage in other small rivers has increased reversely. Therefore, it is necessary to establish a new flood warning system against flash floods instead of the existing flood warning system. It is a specific character that the damage from flash floods in mountain streams brings much more loss of lives than large river's flood. The purpose of this study is calculating the characteristic of flash floods in streams, analyzing topographical characteristics of water basin through applying GIS techniques with the calculation as mentioned above and researching what topographical conditions have influence on hydrological flash floods in water basin. The flash flood prediction model we used is made by GIUH (geomorphoclimatic instantaneous unit hydrograph) with hydrologic-topographical technology. As applying the flash flood prediction model, this is a procedure for calculating topographical information in basin: we made a topological data up out of database with utilizing GIS, and we also produced a DEM (digital elevation model) and used it as a topographical data for determining amount of flash floods.

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A study on the Steel Plate Girder Railway bridge in the applying External Post-tensioning Method (강철도교에 대한 외부 후긴장 보강공법의 적용에 관한 연구)

  • Choi Jung-Youl;Park Yong-Gul;Byun Jong Gul
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1034-1039
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    • 2004
  • The major objective of this study is to investigate the effects and application of reinforcement for steel plate girder railway bridge by the external prestressing method. It analyzed the mechanical behaviors of non-ballasted railway bridge with ballast reinforced and external post-tensioning reinforced on the finite clement analysis for the static and dynamic behavior. As a result, the reinforcement of ballasted railway bridge the external prestressing method are obviously effective for the additional dead force which is ballast. The analytical study are carried out to investigate the post-tension force decrease bending behavior and deflection in composite bridge for serviceability. To develop two type FEM model which reflect well the post-tension force transverse distribution behavior of servicing bridge. With the comparing the results of railway bridge with ballast which carried out before the post-tensioning with the results of railway bridge with ballast which carried out after post-tensioning, It is investigated that the additional dead load decrease effect and bending behavior of servicing bridge is effect by the post-tensioning. The reinforcement by using the external tendon can be reducing that structure of a degradation phenomenon by unusual stresses due to additional dead load and other problems.

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New mechanism of thin film growth by charged clusters

  • Hwang, Nong-Moon;Kim, Doh-Yeon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.3
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    • pp.289-294
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    • 1999
  • The charged clusters or particles, which contain hundreds to thousands of atoms or even more, are suggested to from in the gas phase in the thin film processes such as CVD, thermal evaporation, laser ablation, and flame deposition. All of these processes are also phase synthesis of the nanoparticels. Ion-induced or photo-induced nucleation is the main mechanism for the formation of these nanoclusters or nanoparticles in the gas phase. Charge clusters can make a dense film because of its self-organizing characteristics while neutral ones make a porous skeletal structure because of its Brownian coagulation. The charged cluster model can successfully explain the unusual phenomenon of simultaneous deposition and etching taking place in diamond and silicon CVD processes. It also provides a new interpretation on the selective deposition on a conducting material in the CVD process. The epitaxial sticking of the charged clusters on the growing surface is getting difficult as the cluster size increases, resulting in the nanostructure such as cauliflower or granular structures.

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