김성민 교수

We report results of small-signal modulation characteristics of self-assembled 1.3-μm InGaAs-GaAs quantum dot (QD) lasers at room temperature. The narrow ridge-waveguide lasers were fabricated with multistack InGaAs self-assembled QDs in active region. A high characteristic temperature of T/sub o/=210 K with threshold current density of 200A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> was obtained. Small-signal modulation bandwidth of

High-efficiency optical emission past 1.3 /spl mu/m of GaInNAs on GaAs, with an ultimate goal of a high-power 1.55-/spl mu/m vertical-cavity surface-emitting laser (VCSEL), has proven to be elusive. While GaInNAs could theoretically be grown lattice-matched to GaAs with a very small bandgap, wavelengths are actually limited by the N solubility limit and the high In strain limit. By adding Sb to the GaInNAs quaternary, we have observed a remarkable shift toward longer luminescent wavelengths whil

We report two-color InGaAs quantum-dot infrared photodetectors. The InGaAs self-assembled quantum dots were grown on InGaP matrix via metal-organic chemical vapor deposition and fabricated as intersubband photoconductive structure. Bias-controlled two-color photoconductive responses were obtained at two different infrared window, mid-infrared of /spl lambda/=5.5 μm and far-infrared of /spl lambda/=9.2 μm at 77 K. Our devices were operated with low dark currents and high optical gains, and result

본 연구는 전반적인 발달과 사회 정서적인 문제를 선별한 결과와 선별도구인 K-ASQ와K-ASQ:SE를 비교하는데 목적이 있다. 연구대상자는 서울시 S구 총 94개 어린이집 567명의 30개월에서 41개월의 유아였으며 어린이집을 통해서 부모가 설문지를 작성하도록 하였다. 연구 결과는 다음과 같다. 첫째, K-ASQ 검사결과 19.2%인 109명의 유아가 1개 영역 이상에서 위험군으로 선별되었다. 30개월군, 33개월군에서는 소근육운동에서 36개월군에서는 개인사회성영역에서 위험군의 비율이 가장 컸다. 둘째, K-ASQ:SE 검사결과7.9%인 45명이 위험군으로 31.7%인 180명의 유아가 전문적인 의뢰가 요구되는 진단군으로 선별되었다. 또한, 다른 연령군에 비해 33개월군 유아가 유의미하게 높은 점수를 나타내었다. 셋째, K-ASQ와 K-ASQ:SE의 비교를 통해서 본 연구결과, K-ASQ 모든 영역에서 K-ASQ:SE와 상관이 낮은 것으로 나타났다. 본 연구를 통하여 발달선별 검사의

This study demonstrates multi-spectral operation of InGaAs quantum dot infrared photodetectors that display peak responsivity and peak detectivity at 77 K. The applications of multi-spectral infrared sensors are also discussed in detail.

This study analyzes the historical value of the Gyeonyang of a dragon-patterned Jikgeum Dang-ui, preserved at the Academy of Korean Studies; and establishes dragon-patterned Jikgeum silk as a distinct type of ceremonial attire for royal women. Using information derived from the Gyeonyang, the study identifies the background, composition, and weaving techniques associated with production of the dragon-patterned silk. The dimensions and patterns of the fabric were estimated using existing royal ar

OBJECTIVE: Universal suicide risk screening in pediatric primary care settings is lacking, despite the endorsement of this practice by several national organizations. This study explores barriers to and facilitators of implementing universal suicide risk screening in pediatric primary care clinics, with a focus on clinics that had not yet adopted this practice. METHODS: We conducted a qualitative study consisting of semistructured interviews with primary care clinicians and support staff involve

We report the growth and characterization of a new dilute nitride, InNSb quantum dots embedded on both InAs and GaAs substrate. Strain induced, self-assembled quantum dots are grown using solid-source molecular beam epitaxy. For improved growth control, we developed a growth technique similar to atomic layer epitaxial methods. Nitrogen incorporation during formation of quantum dots changes surface energy barrier and causes anisotropic distribution of strain energy, results in formation of closel

Vertical device architectures are attracting attention for power electronics applications owing to their high current capabilities and space-efficient layouts. In this study, we demonstrate a GaN-based vertical heterojunction bipolar transistor employing aluminum-doped zinc oxide (AZO) as the collector layer, deposited by radio frequency sputtering at a low temperature. This low-temperature process avoids thermal damage to the underlying p-GaN base layer and provides a fabrication-compatible rou

This study is a design research for Saenghwal hanbok(生活韓服), which is hanbok that can be worn practically in an everyday setting, using jersey. Saenghwal hanbok emerged in the 1980’s and peaked in popularity during the 1990’s, then declined in the early 2000’s. Interest in Saenghwal hanbok rose again in 2010 among people in their 20’s and 30’s after hanbok brands that appealed to the young consumers appeared. In the past, hanbok was made with woven fabric composed of silk, cotton (綿), and linen (

The present study aimed to investigate the effects of aural and textual input enhancements through movie clips on the learning of parallel structure rules. The participants included a total of 53 second year high school (grade 11) students. Three intact groups were formed among them, with two experimental groups and one control group, in which the experimental groups consisted of an aural input enhancement (AIE) group and a textual input enhancement (TIE) group. The AIE group was provided with a