http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
조장현(Cho, JangHyun),이호달(Lee, HoDal),김희철(Kim, HeeCheul) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5
This is study of Development of multi-purpose rail system and mechanism applied to luggage rooms. Through those things, attractively appeal to especially SUV owners who would like to drive and purchase cars. In this study, we developed a novel storage mechanism that can lead new trends to appeal to consumer purchasing power of usability of luggage room. In terms of technology, we also secured source technologies that enable consumers to utilize various types of rugged spaces, and expanded the range of choices by creating specialized specifications that can appeal more to SUV purchasing power.
Optical Characterization of a 20 Layer AlGaAs/GaAs Multiple Quantum Wells
Luqman Ali,Janghyun Cho,Clare Chisu BYEON,Jin Dong Song,조현준,Jong Su Kim 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.5
A 20-layer Al0:4Ga0:6As/GaAs multiple quantum well (MQW) sample was deposited on a GaAs substrate by using the molecular beam epitaxy (MBE) method. Optical characterization was carried out by power and temperature dependent photoluminescence (PL) for excitation powers ranging from 40 mW to 120 mW and for temperatures ranging from 11 K to 300 K. At low temperature (LT), only one dominant peak appeared in the spectrum with a much higher PL intensity and less broadening with a significant red shift ( 2:4 nm) of the peak as the excitation power was increased. As the temperature was raised to room temperature (RT), increasing excitation power linearly increased the PL with relatively no significant red shift of the main peak, which may be attributed to heavy-hole transitions near the band edge. As the temperature increased, an additional shoulder peak at higher energy are more apparent because the relative intensity of the main peak decreased. Broadening of the shoulder peak was more significant, and its full width at half maximum (FWHM) increased 4.6 nm (> 25% increase). The shoulder peak at higher energy, which is hidden under the high intensity main peak at LT, presumably indicates relative increase in light-hole transitions due to thermal transport as the temperature increases.
Jeong, Hyunjo,Cho, Sungjong,Nam, Kiwoong,Lee, Janghyun The Korean Society for Nondestructive Testing 2016 한국비파괴검사학회지 Vol.36 No.2
The nonlinearity parameter is frequently measured as a sensitive indicator in damaged material characterization or tissue harmonic imaging. Several previous studies have employed the plane wave solution, and ignored the effects of beam diffraction when measuring the non-linearity parameter ${\beta}$. This paper presents a multi-Gaussian beam approach to explicitly derive diffraction corrections for fundamental and second harmonics under quasilinear and paraxial approximation. Their effects on the nonlinearity parameter estimation demonstrate complicated dependence of ${\beta}$ on the transmitter-receiver geometries, frequency, and propagation distance. The diffraction effects on the non-linearity parameter estimation are important even in the nearfield region. Experiments are performed to show that improved ${\beta}$ values can be obtained by considering the diffraction effects.
An Efficient and Accurate Method for Calculating Nonlinear Diffraction Beam Fields
Jeong, Hyunjo,Cho, Sungjong,Nam, Kiwoong,Lee, Janghyun The Korean Society for Nondestructive Testing 2016 한국비파괴검사학회지 Vol.36 No.2
This study develops an efficient and accurate method for calculating nonlinear diffraction beam fields propagating in fluids or solids. The Westervelt equation and quasilinear theory, from which the integral solutions for the fundamental and second harmonics can be obtained, are first considered. A computationally efficient method is then developed using a multi-Gaussian beam (MGB) model that easily separates the diffraction effects from the plane wave solution. The MGB models provide accurate beam fields when compared with the integral solutions for a number of transmitter-receiver geometries. These models can also serve as fast, powerful modeling tools for many nonlinear acoustics applications, especially in making diffraction corrections for the nonlinearity parameter determination, because of their computational efficiency and accuracy.