신기술 동향 : 원자층증착 기술의 특성 및 전망

김양도 한국공학교육학회 ( 구 한국공학기술학회 ) 2005 공학교육동향 Vol.12 No.3

Improvement of solar cell efficiency by applying Si3N4 nanopattern on glass substrate

김양도,신주현,오경석,이정철,이헌 한국물리학회 2014 Current Applied Physics Vol.14 No.9

A cylindrical Si3N4 nanopattern whose heights was 200 nm was fabricated on a glass substrate, and an aluminum-doped zinc oxide (AZO) layer was grown on the nanopatterned glass substrate. The nanopatternwas applied to an amorphous silicon solar cell in order to increase the light-scattering effect, thus enhancing the efficiency of the solar cell. The reflectance of the solar cell on the Si3N4 nanopattern decreased and its absorption increased. Compared to a flat substrate, the short-circuit current density (Jsc) and conversion efficiency of a solar cell on the Si3N4 nanopatterned substrate were improved by 17.9% and 24.2%, respectively, as determined from solar simulator measurements.

원자층증착 기술의 특성 및 전망

김양도 한국공학교육학회 2005 Ingenium(人材니움) Vol.12 No.3

Bacillus licheniformis Xylanase 의 정제와 특성

최양도(Yang Do Choi),한문희(Moon Hi Han),김진미(Jin Mee Kim) 한국미생물생명공학회 1983 한국미생물·생명공학회지 Vol.11 No.3

대학생의 거부민감성이 대인관계문제에 미치는 영향: 경험회피와 정서인식명확성의 매개효과

김아람,양도연,천성문 부경대학교 인문사회과학연구소 2022 인문사회과학연구 Vol.23 No.2

The purpose of this study is to investigate mediated effect of experiential avoidance and emotional clarity that comes from rejection sensitivity of the university student and their interpersonal relations difficulties. The subjects of this study were university students in four cities and they were asked about rejection sensitivity, interpersonal relations problems, experiential avoidance, and emotional clarity with questionnaire. Correlation analysis was conducted so as to examine interrelations of variables by using SPSS 22.0. The findings of this study are the following: First, rejection sensitivity of the university students influences directly on their interpersonal relations problems. Second, rejection sensitivity of the students has an effect on interpersonal relations problems by mediating experiential avoidance. Third, rejection sensitivity of the university students has an influence on interpersonal relations problems by mediating emotional clarity. Fourth, rejection sensitivity of the university students effects on interpersonal relations problems by successively mediating experiential avoidance and emotional clarity. These findings show that if a university student has high level of rejection sensitivity, the student will avoid the experience due to anxiety about rejection and have low level of emotional clarity, and in turn, it can give an effect on interpersonal relations problems. Thus, based on the findings, this study suggests that practical measures for reducing interpersonal relations difficulties of the university students should be discussed and if a university student client who reports interpersonal relations problems and is sensitive to rejection is faced in practical counseling, it is expected that the results of this study can help the student to adjust to interpersonal relations soundly through proper interventions of experiential avoidance and emotional clarity. 본 연구의 목적은 대학생의 거부민감성과 대인관계문제에서 경험회피와 정서인식명확성의 매개효과를 살펴보는데 있다. 이를 위해 본 연구에서는 전국 17개 시도 중 부산광역시, 경상남도, 서울, 경기도, 4개 시도에 소재한 대학에 재학중인 대학생 359명을 대상으로, 거부민감성, 대인관계문제, 경험회피, 정서인식명확성에 관한 설문을 실시하였고, 무성의하게 응답한 12부를 제외한 347부의 설문지를 사용하였다. SPSS 25.0을 사용하여 변인들 간의 관련성을 살펴보기 위해 상관분석을 실시하였고 Hayes(2013)가 제안한 매개모형의 절차에 따라 경로를 분석하여 매개효과를 확인하였다. 본 연구의 결과는 첫째, 대학생의 거부민감성이 대인관계문제에 직접적인 정적 영향을 미치는 것으로 나타났다. 이는 거부민감성이 높은 사람은 대인관계 속에서 더 많은 어려움을 경험하고 호소한다는 것을 의미한다. 둘째, 대학생의 거부민감성 경험회피를 매개로 대인관계문제에 영향을 미치는 것으로 나타났다. 이는 거부민감성이 높을수록 과도한 불안을 느껴 회피반응을 보여 대인관계가 여려워 지는 것으로 이해할 수 있다. 셋째, 대학생의 거부민감성은 정서인식명확성을 매개로 대인관계문제에 영향을 미치는 것으로 나타났다. 이는 거부민간성이 높을수록 정서를 명확하게 인식하고 파악하는 능력이 떨어져 대인관계에서도 부적절한 반응을 하는 것으로 볼 수 있다. 넷째, 대학생의 거부민감성은 경험회피와 정서인식명확성을 순차적 매개하여 대인관계 문제에 영향을 미치는 것으로 나타났다. 이러한 연구결과는 대학생이 거부민감성이 높을수록 타인의 거부반응에 예민하게 반응하여 경험을 회피하고 이로인해 고통스러운 정서나 생각을 지속적으로 피하게 되어 정서를 명확히 인식하지 못함으로써 대인관계문제에 영향을 줄 수 있음을 시사한다. 본 연구는 대학생 내담자의 대인관계문제를 감소시키기 위한 교육 및 상담 프로그램 개발의 기초자료로 활용될 수 있을 것이다.

육방정 질화붕소 나노입자 합성 및 열전도성 복합체 응용

정재용,김양도,신평우,김영국,Jung, Jae-Yong,Kim, Yang-Do,Shin, Pyung-Woo,Kim, Young-Kuk 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.6

Much attention has been paid to thermally conductive materials for efficient heat dissipation of electronic devices to maintain their functionality and to support lifetime span. Hexagonal boron nitride (h-BN), which has a high thermal conductivity, is one of the most suitable materials for thermally conductive composites. In this study, we synthesize h-BN nanocrystals by pyrolysis of cost-effective precursors, boric acid, and melamine. Through pyrolysis at $900^{\circ}C$ and subsequent annealing at $1500^{\circ}C$, h-BN nanoparticles with diameters of ~80 nm are synthesized. We demonstrate that the addition of small amounts of Eu-containing salts during the preparation of melamine borate precursors significantly enhanced the crystallinity of h-BN. In particular, addition of Eu assists the growth of h-BN nanoplatelets with diameters up to ~200 nm. Polymer composites containing both spherical $Al_2O_3$ (70 vol%) and Eu-doped h-BN nanoparticles (4 vol%) show an enhanced thermal conductivity (${\lambda}{\sim}1.72W/mK$), which is larger than the thermal conductivity of polymer composites containing spherical $Al_2O_3$ (70 vol%) as the sole fillers (${\lambda}{\sim}1.48W/mK$).

PVA 함유 수용액으로부터 초음파 조사에 의한 CdSe 중공 입자의 합성

박명국,김양도,이윤복,김용진,김인배 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.2

CdSe hollow spheres with the diameter of about 30-50 nm were synthesized after ultrasonic irradiation in the presence of Cd(NO3)2, Na2SeSO3, and polyvinylalcohol (PVA). The characteristics of CdSe hollow spheres were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis measurement and PL spectrometer. The characteristics of solvent as water and water- 1-propanol mixture in the system played important roles on the controlled synthesis of hollow sphere. Based on the observation of morphological difference of CdSe, the possible mechanism of CdSe hollow sphere formation will be discussed.

무인항공기용 150W급 연료전지 동력원 개발 및 실증

양철남,김양도 한국수소및신에너지학회 2012 한국수소 및 신에너지학회논문집 Vol.23 No.4

Long endurance is a key issue in the application of unmanned aerial vehicles. This study presents feasibility test results when fuel cell system as an alternative to the conventional engine is applied for the power of the UAV after the 150W fuel cell system is developed and packaged to the 1/4 scale super cub airplane. Fuel cell system is operated by dead-end method in the anode part and periodically purged to remove the water droplet in flow field during the operation. Oxygen in the air is supplied to the stack by the two air blowers. And fuel cell stack is water cooled by cooling circuit to dissipate the heat generated during the fuel cell operation. Weight balance is considered to integrate the stack and balance of plant (BOP) in package layout. In flight performance test, we demonstrated 4 times standalone take-off and landing. In the laboratory test simulating the flight condition to quantify the energy flow, the system is analyzed in detail. Sankey diagram shows that electric efficiency of the fuel cell system is 39.2%, heat loss 50.1%, parasitic loss 8.96%, and unreacted purged gas 1.67%, respectively compared to the total hydrogen input energy. Feasibility test results show that fuel cell system is high efficient and appropriate for the power of UAV.

패턴서치 전역최적화 기법을 이용한 지구-달 L2 의사-할로 궤도 투입 기동 계획연구

이상철,김해동,양도철,조동현,임정흠,노태수,김승균,석진영 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

지구-달 L2 의사-할로 궤도에 위성을 위치시키면 달의 반대쪽과 지구와의 연속적인 통신이 가능해지는 장점과 태양계탐사를 위한 달정거장으로 이용이 가능하며, 반복적인 궤도로 위성의 설계와 운용이 편리한 장점이 있다. 이러한 임무수행을 위해서, 위성은 지구 궤도에서 L2 근처로 이동하고, 다시 L2 근처의 지구-달 L2 의사-할로 궤도에 투입되어야 한다. 하지만 지구 근접궤도와 달리 라그랑지포인트 궤도는 지구와 달의 중력 평형에 있기 때문에 불안정한 운동을 한다. 본 연구에서는 우주물체와의 충돌회피를 고려하여, 위성을 지구-달 L2 포인트에 투입하기 위해서 패턴서치 기법을 사용하여 기동계획을 생성하였다. 수행결과, 패턴서치 전역최적화 기법에 의해 생성된 기동은 초기에 선정된 경로를 따라가며 물체와의 충돌을 회피함을 확인하였다. A spacecraft placed on an Earth-Moon L2 quasi-halo orbit can keep continuous line-of-sight communications between the Earth and the far side of the Moon, and it can be used a lunar space station to explorer the solar system. Benefiting from the repeated orbit characteristics, it is convenient to design the orbit and operate a satellite in it. For this mission, a spacecraft should be transferred from Earth to the vicinity of that point. Also, the spacecraft needs to be inserted onto the Earth-Moon L2 quasi-halo orbit. In this paper, an insertion maneuver is studied for a spacecraft on Earth-Moon L2 quasi-halo orbit using the pattern search global optimization algorithm with considering collision avoidance. Results show that the spacecraft can maintain its own trajectory on the Earth-Moon L2 quasi-halo orbit avoiding collision from a threatening object.

Characteristic of Ga-Doped ZnO Films Deposited by DC Magnetron Sputtering with a Sintered Ceramic ZnO:Ga Target

송풍근,김양도 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

GZO films were deposited using various GZO targets with different Ga2O3 concentrations by DC magnetron sputering. The UV emision intensity remarkably increased for Ga concentrations up to 6.65 wt% Ga2O3, but decreased again with further increases in the Ga2O3 content. Relatively good PL intensity and electrical properties were obtained for the GZO film deposited at a Ga2O3 concentration of 6.65 wt%. The UV emision centered at about 360 nm (3.44 eV) might originate from excitonic recombination coresponding to the near-band-edge emision. On the other hand, blue-grenemision(BGE) intensity monotonously increased with increasing Ga2O3 concentration, which might be atributed to oxygen vacancies. A relatively low resistiviy of 5.1 × 10-4 Ωcm was obtained for the GZO lms deposited at 6.65 wt% of Ga2O3. As a result, increased doping efficiency in GZO films can be said to enhance the UV emision intensity. cm was obtained for the GZO lms deposited at 6.65 wt% of Ga2O3. As a result, increased doping eciency in GZO lms can be said to enhance the UV emision intensity.