약속어음의 발행인과 배서인이 소지인에 대하여 지는 합동책임

박승환 한국상사판례학회 1989 상사판례연구 Vol.3 No.1

InGaAs/GaAs 양자우물 표면발광레이저 설계에 관한 연구

박승환,정원국,김인,최병두,임한조 대구효성가톨릭대학교 자연과학연구소 1993 基礎科學硏究論集 Vol.1993 No.1

InGaAs/GaAs 양자우물 표면발광레이저(0.98㎛)의 문턱전류밀도에 대한 최적화 조건을 이론적으로 조사 연구하였다. Material gain은 strain과 band-mixing을 고려하여 계산하였고, 이것으로부터 active layer내 최적의 양자우물 수 그리고 최적의 active layer 수를 결정하고자 하였다. 반사율 R=0.95에 대해,periodic gain structure(PGS)는 한 개의 active layer를 가진 uniform gain structure(UGS)에 비해 3배정도로 문턱전류가 낮았으며, PGS의 최적 양자우물 수는 2, 그리고 최적의 cavity length는 반파장의 17배 정도로 나타났다. 또한, UGS는 4개의 양자우물에서 최소의 문턱전류밀도를 보여주었다. Optimization conditions of the threshold current density in InGaAs/GaAs quantum well(QW)surface-emitting laser(SEL)(0.98㎛)are studied theoretically. Material gain is caculated by considering strain and band-mixing effects. From this, QW number in active layer and numbers of active layer are optimized. It is found that the periodic gain structure(PGS) can provide a factor of three reduction in threshold current density comparing to the uniform gain structure(UGS) with a single active layer. For PGS, the optimum QW number is two, and the optimum cavity length is 17 half wavelengths. Also, UGS shows that the optimum QW number is four.

Strain Effects on the Optical Properties of Compressively-strained InGaAs/InP Multiple Quantum Wires

박승환 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.8

Strain effects on the optical properties of compressively-strained InGaAs/InP multiple quantumwires (QWRs) are investigated as functions of the wire thickness along the x direction, Lx, by usinga six-band strain-dependent k·p Hamiltonian. In the case of QWRs with the same initial strains,the transition energy decreases with increasing number of wire layers, and its rate of decrease isshown to increase with increasing Lx. On the other hand, in the case of QWRs with different initialstrains, the transition energy slightly increases with increasing number of wire layers and its rateof increase is nearly independent of Lx. The z-polarized optical matrix element for QWRs withdifferent initial strains is shown to be much larger than that for QWRs with the same initial strains,irrespective of Lx. This can be explained by the fact that the confinement of the wavefunction inthe conduction band is enhanced due to the strain effect.

Ground-state Switching Characteristics in Vertically-coupled InGaN/GaN Quantum Dots

박승환,홍우표,김종재 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.11

The ground-state switching characteristics are investigated as a function of the barrier thicknessin vertically-coupled InGaN/GaN qautntum dots (QDs) by using the effective mass model and thecontinuum theory. In the case of a relatively small dDD (barrier thickness between coupled QDs),the highest potential point is located at the bottom of the lower QD, and the lowest potential pointis located at the top of the upper QD. On the other hand, in the case of a relatively thick barrier(dDD = 80 °A), the highest potential point is shifted to the bottom of the upper QD while the lowestpotential point remains at the top of the upper QD. As a result, a ground-state switching for theelectron is observed. We know that the upper boundary barrier thickness dB2 affects the lowestpotential point and that a ground-state switching for the hole is observed with increasing dB2. Thetransition energy is observed to decrease slightly with increasing dDD or dB2.

Effects of Polarization Field on Vertical Transport in GaN/AlGaN Resonant Tunneling Diodes

박승환,심종인 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.11

Polarization-field effects on the vertical transport in GaN/AlGaN resonant tunneling diodes (RTDs) were theoretically investigated by using the transfer matrix formalism. The self-consistent model shows that the resonant peaks are shifted toward higher energies with increasing Al composition in the AlGaN barrier, and the transmission probability values are shown to decrease rapidly. In the case of the flat-band model, on the other hand, the shift of the resonant peaks is smaller than it is for the self-consistent model and the variation of transmission probability values with increasing Al composition is relatively smaller than that of the self-consistent model. The currentvoltage characteristics of the self-consistent model are asymmetric while those of the flat-band model are symmetric for positive and negative current directions. The peak-to-valley ratio (PVR) of the self-consistent model is shown to be slightly smaller than that of the flat-band model for Al = 0.3.

Optical Polarization Anisoptopy in a-plane GaN/AlGaN Quantum-well Structures

박승환 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.8

Optical anisotropy as a function of Al composition of the (11 2 0) a-plane GaN/AlxGa1−xNquantum-well (QW) structures was investigated using a non-Markovian optical model. The energyspacing between the first two subbands is shown to increase with increasing Al composition x inthe barrier. The QW structure with a larger x has a larger optical matrix element than that with asmaller x because the potential well becomes deeper for QW structures with a larger x. Hence, thepeak intensity of the optical gain rapidly increases with increasing Al composition in the AlGaNbarrier, and the rate of increase of the x0-polarized optical gain with increasing Al content is largerthan that of the y0-polarized optical gain. As a result, the absolute value of the anisotropy is foundto decrease greatly with increasing Al composition. The optical anisotropy values are 0.74 and 0.40for x = 0.1 and 0.3, respectively.

Reduction in Built-in Polarization Potentials in Three Vertically Arranged InGaN/GaN Quantum Dots

박승환,홍우표 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.5

The barrier thickness dependence of built-in polarization potentials is investigated using finite-element method (FEM) based on the theory of continuum elasticity for three vertically arranged InGaN/GaN quantum dot (QD) structures. In the case of a relatively thick barrier thickness <i>d_DD</i>?between QDs, the potential drop in a lower or centered QD is similar to that of the QW structure. However, the potential drop significantly decreases with decreasing <i>d_DD</i>.?In addition, the potential drop in QDs is found to depend on a lower boundary barrier thickness <i>d_B1</i>?and is shown to decrease with decreasing?<i>d_B1</i>. On the other hand,?the?<i>d_DD</i>?dependence of the potential drop is not as large as its?<i>d_B1</i>?dependence. This means that the detailed knowledge of barrier thickness dependences of the internal potential is important in designing vertically arranged InGaN-based QD structures.

제조 공정 빅 데이터를 활용한 클러스터링 기반 특질 추출

박승환,백준걸 한국경영과학회 2014 한국경영과학회 학술대회논문집 Vol.2014 No.5

농산물 원산지효과가 지각에 미치는 영향

박승환 한국경영법률학회 2007 經營法律 Vol.17 No.4

【Abstract】 The Impact of Country-of-Origin Effects on Consumers' Perceptions of Agricultural Product Quality Park, Seung-Whan This study aims to identify the consequence of country-of-origin effect and verify the perception of imported products by demographic characteristics for the purpose of investigating consumers' perceptions about imported agricultural products in korea market. This research is empirically to examine the consumers' perceptions of country-of-origin effect about imported agricultural products. the questionnaire method was adopted to collect the data for this study. A seven-point likert scale was used in this questionnaire. And this research employ both AMOS 5.0 and SPSS 12.0 for an empirical approach. It was found as follows: First, information factors of imported agricultural products that constitute country-of-origin information dimensions toward customers' perceptions are social assurers, security seekers and price vetters. it revealed that price vetter is most important factor of imported agricultural products. and it confirmed that consumer who want to purchase imported agricultural products seek for price vetters totally. Second, there is difference a certain degree of preference by product types of imported agricultural products. there are difference from consumers' perception by types of imported agricultural products such as spices, vegetables, grains and fruits. Third, it identify that there is no different consumers' perceptions about imported agricultural products by demographic characteristics except for the variable of married or not married. In conclusion, the marketers of agricultural product company should be identified that most important factors to their customer and provided it to them because it will be formulating loyalty of customers and increasing profit of agricultural product company.

골프장 이용자의 시설 및 지도자 만족도에 관한 연구

박승환,유중근 한국스포츠학회 2011 한국스포츠학회지 Vol.9 No.3