http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
자아결상원리의 오차 해석을 통한 다중모드간섭기의 최적화
홍정무,오범환,이승걸,이일항,우덕하,김선호 한국광학회 2002 한국광학회지 Vol.13 No.1
다중모드간섭기의 자아결상(Self-Imaging)원리는 다중모드의 전파상수를 근사한 식에서 출발한다. 이러한 근사로 인해 발생하는 위상오차를 최소화하기 위해 기존 방식의 문제와 한계를 고찰하고, 위상오차의 근본적인 해석을 통하여 위상오차의 한계범위 내에 포함되는 모드수를 극대화한 최적 구조를 결정할 수 있었으며, 대표모드를 설정하여 기준으로 삼으면 이에 근접한 결과를 보다 쉽게 얻을 수 있었다. 다중모드간의 위상오차를 효율적으로 줄이는 최적구조를 원리적으로 제대로 구현함으로써, 다중모드간섭을 이용한 소자들 전반에 걸쳐 더욱 향상된 특성을 갖는 소자제작이 가능할 것으로 기대된다. Simple principles of self-imaging in Multi-Mode Interference (MMI) devices are based on the approximation of propagation constants. The analysis of the basic nature of the self-imaging principle reveals the problems of previous optimization methods, and provides a new scheme to optimize the external variables for the reconciliation of approximation problems by considering two different tendencies of approximation effects. Furthermore, the representative mode method is proposed to make the application easy. This optimization method provides an essential method for stable design and fabrication of MMI devices with improved characteristics.
다층조건에서 CPT를 이용한 말뚝의 극한수평지지력 평가 분석 및 수정 수평토압분포 제안
홍정무,경두현,강병준,이준환 한국지반공학회 2009 한국지반공학회논문집 Vol.25 No.6
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.
수평토압분포를 고려한 CPT기반의 말뚝극한수평지지력 산정
김민기,홍정무,경두현,이준환 한국지반공학회 2009 한국지반공학회논문집 Vol.25 No.2
In this study, estimation methodology for the pile of ultimation lateral resistance, pu, and ultimate lateral capacity, Hu, is based on the CPT cone resistance qc. Preexistent methodologies for ultimate lateral resistance and ultimate lateral capacity have been generally represented with relative density, vertical effective stresses, and various K0 values which are important for analyzing sandy soil. These methodologies, however, did not consider the horizontal effective stress and the effects of construction site conditions. Therefore, CPT-based methodology for the estimation of the ultimate lateral pile load capacity Hu was proposed. Calibration chamber test results were analyzed and compared with calculated results. The proposed estimation methodology for the pile of pu can be effectively utilized as alternative to preexistent methods.
다층지반에 관입된 강성말뚝의 수평 거동 및 수평 지지력 특성
경두현,홍정무,강병준,이준환 한국지반공학회 2009 한국지반공학회논문집 Vol.25 No.4
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).
강병준,홍정무,경두현,이준환 한국지반공학회 2009 한국지반공학회논문집 Vol.25 No.1
One of the important use of piles is to furnish lateral support and nowadays it is getting highlighted due to the increase of skyscrapers, transmission towers, wind turbines, and other lateral action dependent structures. After Broms (1964), many researchers have suggested methods for estimating lateral capacity of pile. But each method assumes different earth pressure distribution and lateral earth pressure coefficient causing confusion on the part of pile designers. Lateral earth pressure, essential in lateral capacity estimation, is influenced by pile’s rotational behavior under lateral load. Prasad and Chari (1999) assumed the rotation point of pile and suggested an equation of ultimate lateral load capacity. In this study, we investigate the depth of rotation point in both homogeneous soil and multi layered soil, and compare with the estimation value by previous research. Test results show that measured rotation point and estimated value by Prasad and Chari’s equation show good agreement and multi layered condition affects the location of rotation point to be changed.
사질토지반에서 콘관입저항치 qc에 의한 단말뚝의 극한수평단위지지력 평가
김민기,홍정무,경두현,이준환 한국지반공학회 2008 한국지반공학회논문집 Vol.24 No.11
In this study, CPT-based methodology for estimating the ultimate lateral resistance, pu, is proposed and verified for lateral loaded piles in sandy soil. Preexistent methods estimating the ultimate lateral resistance, pu, and the ultimate lateral capacity, Hu, of pile have been based on the vertical effective stress, relative density, and the coefficient of lateral earth pressure. Similarly, cone resistance qc in pure sandy soil is expressed by those essential factors. As correlation between pu and qc are normalized with average effective stress σm, estimation methodology for the lateral loaded pile of pu in sandy soil is proposed. The method is verified by calibration chamber test results in pure sand. The standard derivation of estimated pu is 0.279, and COV (Coefficient Of Variation) of estimated pu is 0.272. These results showed that the estimated pus by the method are analogous with the measured pus in calibration chamber test.