• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.77-90
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• 2009

In this study, experimental analysis was performed about lateral load capacity and behavior of laterally loaded-bored rigid piles in muti-layered soil conditions. Lateral pile load tests were performed for muti-layerd soils consisting of different relative density. Ultimated lateral load capacities were measured from lateral load-displacement curves and compared with estimated values using theoretical methods. Bending moments and unit lateral capacity distribution of surrounding piles were measured from attached strain gauges and earth pressure sensors on the pile. It was found that ultimated lateral load capacities were different from the muti-layered soil conditions, and measured values were lower than estimated values. The bending moment distributions of the pile were similar all the time. Unit lateral capacity distributions were a little different from muti-layered soil conditions, but basically similar to the distribution proposed by Prasad and Chari (1999).

• 전기의세계
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• v.39 no.12
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• pp.63-67
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• 1990

MOSFET의 드레인 불순물 농도 분포는 hot carrier효과 및 드레인 누설전류 특성에서 중요한 요소가 된다. 특히 MOSFET의 게이트 아래 부분의 수평 농도는 게이트 전압에 의한 누설전류 특성에 큰 영향을 주는 것으로 알려져 있다.[1][2]. 보통의 수직농도분포는 SIMS기법, ARS 방법등을 이용하여 측정이 가능하다. 그러나, 수평 불순물 농도분포는 실험적으로 구하는 방법이 없었고 보통 이차원 공정 시뮬레이션(MINIMOS, SUPRA등)을 통하여 산출하였다. 최근 드레인의 수평 불순물 농도분포를 게이트와 드레인 사이의 용량 측정에 의해 구하는 방법이 제시되었다[3]. 이방법에서는 농도가 높은 경우에는 수평접합깊이를 절대적인 값으로 구하지 못하였다. 본 논문에서는 게이트-드레인간 용량 측정에 의해 수평접합깊이를 구하고 그 농도분포를 추출하는 방법을 제시하고, ASR방법에 의해 측정된 수직 불순물 농도분포와 비교하고 검토한다.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.47-57
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• 2009

In this study, the ultimate lateral load capacity of pile driven into multi-layered soil was estimated using cone penetration test results and a method was proposed to reflect multi-layered soil conditions. For multi-layered specimens prepared with different relative density at different layers, the cone penetration tests and lateral pile load tests were conducted. Based on the test results, measured and estimated values of the ultimate lateral load were compared and analyzed. The estimated results were obtained from the methods proposed by Broms (1964), Petrasovits & Award (1972) and Prasad & Chari (1999). The method was proposed for modifying the earth pressure distribution of Prasad & Chari (1999) to consider multi-layered soil conditions. From the analysis, it was seen that results obtained from the proposed method showed improvement with less data scatter similarly to those obtained from Broms (1964) and Petrasovits & Award (1972)'s methods.

• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.131-142
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• 2022

In order to examine the possibility of horizontal simulations of acoustic waves on the environments of big water depth variations, this study introduces a 3-dimensional model based on the pababolic equation. The model gives approximated solutions by separating the cross- and non cross-terms in the equation. Assuming artificial bathymetry (25 km × 4 km) with a source frequency 75 Hz, the simulations give clear horizontal refractions on the transmission loss distributions. The degree of refractions shows non-linear increase along the propagating range and proportional increase with water depth along the cross range. Another simulations with the real bathymetry (25 km × 8 km) also give clear horizontal refractions. The horizontal distributions present little difference with the depth resolution variations of the same data source because the model gives interpolations over the depth data before simulations. Meanwhile, the horizontal distributions show big difference with those of different data sources.

• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.449-458
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• 2010

This study attempted to investigate the effect of panel thickness on the horizontal density distribution (HDD) of medium density fiberboard (MDF) in a destructive way. Full size MDF panels with five different thicknesses such as 2 mm, 4.5 mm, 9 mm, 18 mm and 30 mm were cut into two different specimen sizes, i.e., $500{\times}500\;mm$ and $120{\times}120\;mm$ to measure the HDD. In general, the overall density of MDF panel diminished as the thickness increased, showing the highest density for the thinnest MDF panels. The HDD variation was significant for the samples of smaller specimen size ($120{\times}120\;mm$). MDF panel thickness significantly influenced to the HDD, which increased as the thickness decreased. In addition, the thinner panels showed much wider range in the HDD than those of thicker panels. The coefficient of variation (COV) of HDD also followed a similar trend to the panel density as the thickness increased. In summary, MDF panel thickness had a significant impact on the HDD within a panel. The sample size also showed a considerable effect to the HDD of MDF panels.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.103-110
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• 2005

In this paper, the characteristics of excessive horizontal stress components in Korea were studied using more than five hundred measured data set of in-situ hydraulic fracturing test. Based on the in-situ testing data, the magnitude and orientation of the horizontal stress component and variation of stress ratio (K) with depth were investigated. And also horizontal stress magnitude versus depth relationships and distribution limits of stress ratio components were suggested. For the depth less than 310 m in the entire territory, the stress ratio has a tendency to diminish and stabilize with depth, but fur some areas, it was revealed that the excessive horizontal stress fields with stress ratio close to 3.0 below 200 m in depth have formed. The results from the investigation of excessive horizontal stress regions showed that there existed several regions where the localized excessive horizontal stress was big enough to potentially induce brittle failure around the openings at less than 300 m in depth.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.151-161
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• 2003

The spatiotemporal distribution of resuspended solid on the shelf of the southern Yellow Sea and the northern East China Sea was studied. The sea surface reflectance imageries obtained by remote sensing using satellite at channels of red (620~670nm), green(545~565nm) and blue(459~479nm) from Terra MODIS were used to explain the front of the high concentration suspended solid(SS) on the shelf in the East China Sea. The horizontal distribution of the resuspended solid was depended on the wind force, tidal current and stratification of water. The horizontal distribution areas of the resuspended solid in winter season during January~April, 2002 were three times wider than those in summer season during June~September, 2001.

• Journal of the Korean Geographical Society
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• v.33 no.2
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• pp.191-208
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• 1998

제주도의 기온온난화가 한라산 고산식물 분포에 미치는 영향에 대한 연구의 하나로 한라산 고산식물 8종의 수평 및 수직 분포역과 생육환경이 조사되었다. 그 결과 희귀하거나 멸종 위기 상태에 있는 고산식물들에 관한 생물지리학적 기초 자료와 정보가 축적되었다. 한라산 고산식물은 분포특성에 따라 8가지 유형으로 분류되며, 그 중 70퍼센트 정도가 한반도의 고산지나 일본열도의 것들과 공통적인 것으로 밝혀졌다. 이들은 빙하기 동안 동북아시아에서 한반도를 거쳐 제주도로 유입되었고, 일부는 일본열도에 전파된 것으로 생각된다. 현재 이들 고산식물은 열악한 기후, 척박한 토질과 지질 그리고 동결과 융해가 반복되는 주빙하성 환경에 적응하여 산정부 일대에 주로 분포한다. 본 연구는 한라산 고산식물의 분포와 과거 및 현재 환경과의 관계에 대한 기초 자료를 구축하여, 한반도의 자연환경 변천사를 파악하고, 기온온난화가 지속될 때 한라산 고산경관과 생태계가 당면할 문제를 파악하고 대안을 제시하는데 필요한 정보를 제공할 것으로 기대된다.

• Journal of the Korean Geotechnical Society
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• v.17 no.3
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• pp.83-94
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• 2001

본 연구에서는 상.하단으로 구분된 2개의 동일한 보강토옹벽에 대해서 상호 이격거리에 따른 수치해석을 수행하여 전면벽체의 수평변위, 전면벽체 배면의 수평토압, 보강토체 배면의 수평토압 그리고 보강재의 최대인장력 분포 및 크기변화 양상 등 다단식 보강토옹벽의 거동을 살펴보았다. 또한, 하단 옹벽에 증가되는 응력을 산정하고자 중첩의 원리를 적용한 2:1 응력분포법을 제시하였다. 수치해석 결과 이격거리가 증가함에 따라 상단옹벽이 하단옹벽에 미치는 영향이 감소하였으며 하단 옹벽 높이의 두배 이상 이격시, 상호 거동은 독립옹벽으로 거동하였다. 하단 옹벽내 응력 산정방법에 있어서 NCMA의 방법이 가장 보수적인 결과를 보였으며 본 연구에서 제시한 2:1 응력분포법중 주동파괴면을 고려하지 않은 방법이 수치해석 결과와 가장 유사하게 나타났다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.966-975
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• 1986

유한한 열전도율과 두께를 갖는 수평동심원관 내의 층류자연대류 문제를 유한차분법을 사용하여 수치적으로 연구하였다. 동심원관 내에는 전도-대류가 복합되어, 전체-유체 경계면에서의 온도분포는 미리 알려져 있지 않다. Prandtl수를 0.7, L/D$_{i}$ = 0.8로 고정하고 각각의 Rayleigh수와 열전도계수의 비, 기하학적변수에 대하여 계산을 수행하였으며, 그 결과를 등온 수평동심원관의 경우와 비교하였다. Rayleigh수와 t/D$_{i}$가 클수록, 열전도계수의 비 K가 작을수록 열저도 효과는 강하게 나타났으며, 국소등가전도계수와 온도분포에 비하여 속도분포는 영향을 덜 받는다는 것이 밝혀졌다.