• 한국지반신소재학회논문집
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• 제19권4호
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• pp.95-109
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• 2020

본 연구에서는 휴대형 동적콘관입시험(DCPT)을 활용하여 손상된 보강토옹벽의 피해원인을 규명하고 대책방안을 마련한 총 6곳의 현장사례를 검토하여 휴대형 동적콘관입시험의 현장 적용성을 평가하였다. 현장에서는 하부 로트의 결합 연장을 통하여 6m 이상의 지반조사가 가능하도록 개량된 동적콘관입시험기를 사용하였으며, 그 결과를 표준관입시험 결과와 비교하여 상관 관계를 분석하였다. 다양한 현장 적용사례 분석을 통하여, 휴대형 동적콘관입시험이 손상된 보강토옹벽 현장에서의 적용이 매우 편리하며, 연속적으로 개략적인 지반강성을 파악하여 옹벽의 피해원인을 규명하고 안정성을 확인하는데 큰 역할을 할 수 있음을 알 수 있었다. 또한, 동적콘관입시험 및 표준관입시험 결과를 비교, 분석해 본 결과, 사질토 지반에서는 N≒(1/3~2/3)·Nd 정도의 상관관계가 나타남을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제53권2호
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• pp.227-248
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• 2015

A CFPBS (Cone-type Friction Pendulum Bearing System) was developed to control the acceleration delivered to a structure to prevent the damage and degradation of critical communication equipment during earthquakes. This study evaluated the isolation performance of the CFPBS by numerical analysis. The CFPBS was manufactured in the shape of a cone differenced with the existing FPS (Friction Pendulum System), and a pattern was engraved on the friction surface. The natural frequencies of the CFPBS were evaluated from a free-vibration test with a seismic isolator system consisting of 4 CFPBS. To confirm the earthquake-resistant performance, a numerical analysis program was prepared using the equation of the CFPBS induced from the equations of motion. The equation reported by Tsai for the rolling-type seismic isolation bearings was proposed to design the equation of the CFPBS. Artificial seismic waves that satisfy the maximum earthquake scale of the Korean Building Code-Structural (KBC-2005) were created and verified to review the earthquake-resistant performance of the CFPBS by numerical analysis. The superstructural mass of the CFPBS and the skew angle of friction surface were considered for numerical analysis with El Centro NS, Kobe NS and artificial seismic waves. The CFPBS isolation performance evaluation was based on the numerical analysis results, and comparative analysis was performed between the results from numerical analysis and simplified theoretical equation under the same conditions. The validity of numerical analysis was verified from the shaking table test.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.744-751
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• 2006

In case of the Soil Nail System applied to a slope, effects of vibrations from blasting, earthquake and creep of long term behaviors cause reductions of adhesion between grout and soil-nail. There are some reports of nail's pull-out failure by those reasons. In this paper it is suggested that the Cone Nailing System is enable to diminish effects of vibrations and creep. In this study on Cone Nailing System, the cones are installed to each nail by 2m. By such installing cones, the adhesion between nail and grout will increase and the long term creep behavior will decrease. In this study, the centrifuge test is performed to understand the behaviors of the Cone Nail System. For the centrifuge test, the soil tank is 52cm in width, 17cm in length and 35cm in height. In comparison with general soil nail, the centrifuge test of general soil nail(without cone) is performed equally. Additionally, the interface between cone nail and soil through the pull-out test is applied to FLAC 2D version 3.3. and the evaluation of application for the Cone Nail System in slope is performed.

• 한국산림과학회지
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• 제96권3호
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• pp.317-324
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• 2007

종자 공급 방안 개선에 필요한 기초 자료 획득을 위해 소나무 우량 임분 3개소를 대상으로 2003년부터 2006년까지 구과 생산량에 따른 종자 및 발아 특성을 분석한 결과 다음과 같은 결과를 얻었다. 구과 생산량은 2년을 주기로 하여 풍 흉 상태를 보였다. 주요 종자 특성 중 종자 생산 능력과 충실 종자율은 대체적으로 구과 생산량과 유사한 경향을 보인 반면 성숙 종자율과 종자 효율은 반대 경향을 나타내었다. 종자 특성과 구과 생산량과의 회귀분석 결과에서도 종자 생산 능력 ($R^2=0.682$, p<0.01)과 충실 종자율($R^2=0.l61$, non-significant)은 정(+)의 경향을, 성숙 종자율($R^2=0.418$, p<0.05)과 종자 효율($R^2=0.308$, non-significant)은 부(-)의 경향을 나타내었다. 발아 특성에 있어서 발아율은 대체적으로 구과 생산량과 유사한 경향으로 나타났으나, 평균 발아 일수는 반대의 경향을 보였다. 회귀분석결과에서도 발아율은 구과 생산량과 정(+)의 관계($R^2=0.576$, p<0.01)를 보인 반면, 평균 발아 일수는 부(-)의 관계($R^2=0.400$, p<0.05)를 보여 구과 생산량이 많은 시기에 이를 채취하여 사용할 때 발아율도 높고 발아에 소요되는 기간도 짧아져 즉, 발아 효율이 높아짐을 알 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2971-2976
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• 2007

The mode change from Taylor cone-jet to dripping in electrospraying has been analytically investigated. The change has been predicted by the dynamic behavior of a liquid drop at the tip of the cone-jet. Conservation laws are applied to determine the upward motion of the drop, and an instability model of electrified jets is used to determine the jet breakup. Finally, for the first time, the analysis enables prediction of the transition in terms of the Weber number and electric Bond number. The predictions are in good agreement with experimental data.

• Tribology and Lubricants
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• 제19권5호
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• pp.259-267
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• 2003

A brake device for the high-speed impacting object is designed using an axial crushing of thin-walled metal cylinder. Thickness of the cylinder is increased smoothly from the impacting end to the fixed end, resulting in the truncated cone shape. Truncated cone shape minimizes the imperfection-sensitivity of the structure and ensures that plastic hinges are formed sequentially from impacting end. This prevents the undesirable sudden rise in the first peak-crushing load. Several specimens with different conic angles, mean thickness of the wall, and materials were designed and quasi-static compression tests were performed on them. Results indicate that adoption of appropriate conic angle prevents simultaneous wrinkles generation and sudden rise of crushing load and that appropriate conic angle differs in each case, depending on the geometry and material property of the cylinder. Finite element analysis was performed for static compression of the cylinder and its accuracy was checked for the future application.

• 대한전자공학회논문지
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• 제27권3호
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• pp.47-53
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• 1990

곡선의 다각형 근사화 방법은 화상분석 또는 데이타 압축등에 많이 사용된다. 다각형 근사화 방법으로, 적은 break point수를 갖고, Sequential Process로 결과를 얻을 수 있는 Cone intersection 방법이 있다. 여기서는 화소간의 거리가 일정한 디지탈 곡선의 경우, 종래의 cone intersection 방법을 정수계산을 이용하여 속도를 향상시키는 방법을 제안한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.621-623
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• 1993

This paper describes the research in condenser cone of sealing-end for 154kV oil-filled underground cable. We conducted the design based on the results of electric field analysis by electrostatics theory and FEM. In case that condenser cone type EB-A was compared with bell mouth type EB-A, the results of the AC and lightening impulse voltage test showed improvment of 10 percents.

• Advances in aircraft and spacecraft science
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• 제10권5호
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• pp.457-471
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• 2023

The paper evaluates the aerodynamic coefficients on a blunt-nose re-entry capsule with a conical cross-section followed by a cone-flare body. A computer code is developed to solve three-dimensional compressible inviscid equationsfor flow over a Space Recovery Experiment (SRE) configuration at different flare-cone half-angle at Mach 6 and angle of attack up to 5°, at 1° interval. The surface pressure variation is numerically integrated to obtain the aerodynamic forces and pitching moment. The numerical analysis reveals the influence of flare-cone geometry on the flow characteristics and aerodynamic coefficients. The numerical results agree with wind tunnel results. Increase of cone-flare angle from 25° to 35° results in increase of normal force slope, axial forebody drag, base drag and location of centre of pressure by 62.5%, 56.2% and 33.13%, respectively, from the basic configuration ofthe SRE of 25°.

• 한국지반공학회지:지반
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• 제6권4호
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• pp.33-42
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• 1990

정적관입저항 또는 선단지지말뚝의 선단지지력을 해석함에 있어서는 유효수직응력이 기준음력으로 사용되어 왔다. 그러나 정적관입저항은 유효수직응력보다 원위치 유효수평응력에 관계된다는 것이 많은 실험연구결과로부터 보고 되었다. 이와같은 문제점을 규명하기 위하여 기 보고된 실험결과를 다시 분석하였으며 실험실에서의 관입시험이 실시되었다. 연구결과 정적관입저항은 유효수직 응력과 유효수평응력 모두에 영향을 받는 것으로 나타나고 있으며 해석시에는 평균주응력이 기준응력으로 사용되어야 함을 결론 지을 수 있었다.