http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
High resolution interferometer with multiple-pass optical configuration
Ahn, Jeongho,Kim, Jong-Ahn,Kang, Chu-Shik,Kim, Jae-Wan,Kim, Soohyun The Optical Society 2009 Optics express Vol.17 No.23
<P>An interferometer having fourteen times higher resolution than a conventional single-pass interferometer has been developed by making multiple-pass optical path. To embody the multiple-pass optical configuration, a two-dimensional corner cube array block was designed, and its symmetric structure minimized the measurement error. The effect from the alignment error and the imperfection of corner cube is calculated as picometer level. An experiment proves that the suggested interferometer has about 45 nm of optical resolution and its nonlinearity is about 0.5 nm in peak-to-valley.</P>
A passive method to compensate nonlinearity in a homodyne interferometer
Ahn, Jeongho,Kim, Jong-Ahn,Kang, Chu-Shik,Kim, Jae Wan,Kim, Soohyun The Optical Society 2009 Optics express Vol.17 No.25
<P>This study presents an analysis of the nonlinearity resulting from polarization crosstalk at a polarizing beam splitter (PBS) and a wave plate (WP) in a homodyne interferometer. From a theoretical approach, a new compensation method involving a realignment of the axes of WPs to some specific angles according to the characteristics of the PBS is introduced. This method suppresses the nonlinearity in a homodyne interferometer to 0.36 nm, which would be 3.75 nm with conventional alignment methods of WPs.</P>
EULER-BERNOULLI BEAM WITH DYNAMIC FRICTIONLESS CONTACT
Jeongho AHN,David E. STEWART 한국산업응용수학회 2005 한국산업응용수학회 학술대회 논문집 Vol.- No.-
In this work, we formulate the frictionless Euler-Bernoulli equation with dynamic contact condition along the length of a thin beam, and then set up a numerical formulation, employing the midpoint rule for the elastic part of the equation and the implicit Euler method for contact conditions. Convergence for our numerical formulation is investigated. The energy functional is defined, and our numerical scheme leads to energy dissipation. Using time discretization and the FEM with B-spline basis functions, we compute numerical solutions. In order to solve the linear complementarity problem that arises in the numerical method, we use a smoothed guarded Newton method. Those numerical schemes are implemented and some interesting numerical results are obtained. We also investigate numerically the question of whether the numerical solutions converge strongly to their limit, and if energy is conserved for the limit. Our numerical results give some evidence that this is so.