• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.682-686
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• 2001

A fundamental structural design consideration for a vehicle is the overall vibration characteristics in bending and torsion. Vibration characteristics of a vehicle system are mainly influenced by dynamic stiffness of the vehicle body structure and material and physical properties of the components attached to the vehicle body structure. The first step in satisfying this requirement is to obtain a satisfactory dynamic model of the vehicle structure. In this paper. modeling techniques of the vehicle components are presented and the effects of the vehicle components on the vibration characteristics of the vehicle are investigated,

• 한국공간구조학회논문집
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• 제15권4호
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• pp.107-114
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• 2015

Large spatial structures can not easily predict the dynamic behavior due to the lack of construction and design practices. The spatial structures are generally analyzed through the numerical simulation and experimental test in order to investigate the seismic response of large spatial structures. In the case of analysis for seismic response of large spatial structure, the many studies by the numerical analysis was carried out, researches by the shaking table test are very rare. In this study, a shaking table test of a small-scale arch structure was conducted and the dynamic characteristics of arch structure are analyzed. And the dynamic characteristics of arch structures are investigated according to the various column cross-section and length. It is found that the natural vibration periods of the small-scaled arch structure that have large column stiffness are very similar to the natural vibration period of the non-column arch structure. And in case of arch structure with large column stiffness, primary natural frequency period by numerical analysis is very similar to the primary natural frequency period of by shaking table test. These are because the dynamic characteristics of the roof structure are affected by the column stiffness of the spatial structure.

• 한국지진공학회논문집
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• 제25권3호
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• pp.129-135
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• 2021

After the manual shutdown of the Wolseong nuclear power plant due to an earthquake in Gyeongju in 2016, anxiety about the earthquake safety of nuclear power plants has become a major social issue. The shear wall structure used as a major structural element in nuclear power plants is widely used as a major structural member because of its high resistance to horizontal loads such as earthquakes. However, due to the complexity of the structure, it is challenging to predict the dynamic characteristics of the structure. In this study, a three-story shear wall structure is fabricated, and the in-structure response characteristics of the shear wall structure are evaluated through shaking table tests. The test is performed using the Gyeongju earthquake that occurred in 2016, and the response characteristics due to the domestic earthquake are evaluated.

• Transactions on Electrical and Electronic Materials
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• 제5권5호
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• pp.169-172
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• 2004

Deep sub-micron device required to get the superior ultra thin gate oxide characteristics. In this research, I will recommend a novel shallow trench isolation structure(STI) for thin gate oxide and a $N_2$O gate oxide 30 $\AA$ by NO ambient process. The local oxidation of silicon(LOCOS) isolation has been replaced by the shallow trench isolation which has less encroachment into the active device area. Also for $N_2$O gate oxide 30 $\AA$, ultra thin gate oxide 30 $\AA$ was formed by using the $N_2$O gate oxide formation method on STI structure and LOCOS structure. For the metal electrode and junction, TiSi$_2$ process was performed by RTP annealing at 850 $^{\circ}C$ for 29 sec. In the viewpoints of the physical characteristics of MOS capacitor, STI structure was confirmed by SEM. STI structure was expected to minimize the oxide loss at the channel edge. Also, STI structure is considered to decrease the threshold voltage, result in a lower Ti/TiN resistance( Ω /cont.) and higher capacitance-gate voltage(C- V) that made the STI structure more effective. In terms of the TDDB(sec) characteristics, the STI structure showed the stable value of 25 % ～ 90 % more than 55 sec. In brief, analysis of the ultra thin gate oxide 30 $\AA$ proved that STI isolation structure and salicidation process presented in this study. I could achieve improved electrical characteristics and reliability for deep submicron devices with 30 $\AA$ $N_2$O gate oxide.

• 한국지리정보학회지
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• 제15권3호
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• pp.13-22
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• 2012

기존의 공간구문론(Space Syntax)을 활용한 공간구조분석(Spatial Structure Analysis)은 가로망(road)에 관한 인자(factor)만을 활용하는 한계를 가지고 있기에, 가로망 인자만이 아닌 지역의 지역적 특성을 고려한 인자를 도출한 현실성 있는 공간구조 분석 방법이 필요한 실정이다. 본 연구는 지역의 공간구조 특성인자를 도출하여 기존의 공간구문론과 GIS와의 통합모델을 구축하여 수정형 공간구조분석 방법을 제시하고 합덕읍 일원의 중심지역을 대상으로 공간구조 분석을 수행하는데 목적이 있다. 이를 위해 전문가 설문조사를 실시하여 지역의 공간구조 특성요인 및 상대적 가중치를 도출하였고, 지역적 특성을 반영하는 인자로 가로망 뿐만 아니라 용도지역, 지가, 건물의 밀집도 요인을 도출하였다. 분석 결과 합덕읍의 경우 도로만을 이용한 기존의 공간구조분석을 활용한 공간구조분석 방법이 실제적인 값을 반영하지 못한 것으로 분석되었고, 지역적 특성 인자를 추가하여 분석한 수정형 공간구조분석 결과가 합덕읍의 현실성을 잘 반영한 것으로 나타났다. 즉, 합덕읍과 같은 경우 개발 축에 따라 가로망이 변화되고 중심성이 변화되는 지역이 아니라, 효율성과 형평성에 의해 가로망이 형성되거나 쇠퇴로 인해 중심성이 변화된 지역이기에 이러한 지역의 경우 지역적 특성을 반영한 방법이 더 적합한 것으로 분석되었다. 향후 지역적 특성을 반영한 공간구조분석 인자 선정 및 파라미터 선정에 관한 더 깊은 연구가 필요하고 다른 지역을 대상으로 시뮬레이션하여, 모델에 대한 상호 검증 및 보완하는 과정이 필요할 것이다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권2호
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• pp.98-103
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• 2009

An RF test structure is proposed and its applicability is confirmed by measuring DC characteristics and high frequency characteristics. Effective mobility extraction is also performed to confirm the validity of proposed test structure. The area of suggested test structure consumed on wafer was decreased by more than 50% and its characteristics do not be degraded compared with conventional structure.

• Coupled systems mechanics
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• 제1권4호
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• pp.381-395
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• 2012

Dynamic response of Pile Supported Structures is highly depended on Soil Pile Structure Interaction. In this paper, by comparison of experimental and numerical dynamic responses of a prototype jacket offshore platform for both hinge based and pile supported boundary conditions, effect of soil-pile-structure interaction on dynamic characteristics of this platform is studied. Jacket and deck of a prototype platform is installed on a hinge-based case first and then platform is installed on eight skirt piles embedded on continuum monolayer sand. Dynamic characteristics of platform in term of natural frequencies, mode shapes and modal damping are compared for both cases. Effects of adding and removing vertical bracing members in top bay of jacket on dynamic characteristics of platform for both boundary conditions are also studied. Numerical simulation of responses for the studied platform is also performed for both mentioned cases using capability of ABAQUS and SACS software. The 3D model using ABAQUS software is created using solid elements for soil and beam elements for jacket, deck and pile members. Mohr-Coulomb failure criterion and pile-soil interface element are used for considering nonlinear pile soil structure interaction. Simplified modeling of soil-pile-structure interaction effect is also studied using SACS software. It is observed that dynamic characteristics of the system changes significantly due to soil-pile-structure interaction. Meanwhile, both of complex and simplified (ABAQUS and SACS, respectively) models can predict this effect accurately for such platforms subjected to dynamic loading in small range of deformation.

• 한국소음진동공학회논문집
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• 제14권7호
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• pp.604-611
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• 2004

It is well known that wall impedance essentially determines how sound wave transmits from one place to another. The wall impedance is related with its dynamic properties : for example, the mass, stiffness, and damping characteristics. It is noteworthy, however, that the wall impedance is also function of spatial characteristics of two spaces that is separated by the wall. This is often referred that the wall is not locally reacting. In this paper, we have attempted to see how the acoustic characteristics of the two spaces is affected by various structure parameters such as density, applied tension, and a normalized length of the wall. Calculations are conducted for two different modally reacting boundary conditions by modal expansion method. The variation of the Helmholtz mode and the structural-dominated mode are analyzed as the structure parameters vary. The displacement distribution of the structure, pressure and active intensity of the inside and outside cavity are presented at the Helmholtz mode and the structure-dominated mode. It is shown that the frequency characteristics are governed by both structure-and fluid-dominated mode. The results exhibit that the density of the structure is the most sensitive design parameter on the frequency characteristics for the coupling system as we could imagine in the beginning. The Helmholtz mode frequency decrease as density increases. However. it increases as applied tension and an opening size increase. The bandwidth of the Helmholtz mode is mainly affected by density of the structure and its opening size.

• 전기학회논문지
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• 제62권11호
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• pp.1566-1570
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• 2013

In this paper, we analyzed the electric characteristics of the OLEDs device of which anode ITO has been treated with the oxygen plasma. We fabricated the basic three-layer structure (ITO / AF / $Alq_3$ / $Cs_2CO_3$ / Al) device, analyzed how the oxygen plasma treatments of the ITO surface affects to the electrical characteristics of OLEDs. We also produced a four-layer structure device (ITO / AF / TPD / $Alq_3$ / $Cs_2CO_3$ / Al) with the oxygen plasma treatment. From the comparative analysis to the devices, we confirmed following results. The three-layer structure OLEDs device with oxygen plasma treatment has better characteristics than the device without the treatments; maximum luminance, luminous efficiency, and external quantum efficiency are improved approximately 151 [%], 126 [%], and 175[%], respectively. Also, the electric characteristics of the four-layer structure device with oxygen plasma treatment are improved comparing to the characteristics of the three-layer structure device with oxygen plasma treatment; maximum luminance, luminous efficiency, and external quantum efficiency are improved approximately 144 [%], 115 [%], and 124[%], respectively.

• 대한전자공학회논문지SD
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• 제48권5호
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• pp.1-5
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• 2011

본 논문에서는 AlGaN/GaN HEMT의 항복 전압 특성 향상을 위해 2차원 소자 시뮬레이터를 통하여 게이트 필드 플레이트 구조를 최적화하였다. 필드플레이트 길이, 절연체 종류, 절연체 두께 변화 등의 세가지 변수를 이용하여 시뮬레이션을 진행하였으며 그에 따른 전기장 분포의 변화와 항복전압 특성을 확인하였다. 필드플레이트 구조를 최적화 시킴으로서 게이트 에지부분과 필드플레이트 에지부분에 집중 되어있던 전기장이 효과적으로 분산된다. 그에 따라 애벌런치 효과가 줄어들게 되어 항복전압 특성이 향상된다. 결론적으로 최적화된 게이트 필드플레이트 구조는 일반적인 구조에 비해 항복특성을 약 300% 이상 향상시킬 수 있다.