HVPE 법을 통한 GaN 성장 시 기판 종류 및 V/III 비에 따른 잔류 stress 특성 연구

이주형,이승훈,이희애,강효상,오누리,이성철,이성국,박재화,Lee, Joo Hyung,Lee, Seung Hoon,Lee, Hee Ae,Kang, Hyo Sang,Oh, Nuri,Yi, Sung Chul,Lee, Seong Kuk,Park, Jae Hwa 한국결정성장학회 2020 한국결정성장학회지 Vol.30 No.2

본 연구에서는 HVPE 성장법으로 GaN 성장 시 GaN 내에 잔류하는 stress로 인한 crack 현상을 감소시키고자 기판 종류 및 V/III 비를 조절하여 잔류 stress 특성을 알아보고자 하였다. Sapphire, GaN template 위에 각각 V/III 비 5, 10, 15의 조건으로 GaN을 성장시켜 형성된 hexagonal pit의 분포 및 깊이를 분석하였다. 이를 통해 GaN on GaN template 성장에서 V/III 비가 높을수록 hexagonal pit의 분포 영역 및 깊이가 증가하는 것을 확인하였다. Raman 측정을 통해 hexagonal pit 영역 및 깊이가 컸던 GaN on GaN template 성장에서 V/III 비가 높을수록 stress가 감소하는 것을 확인하였다. 이를 통해 hexagonal pit의 분포 및 깊이가 증가할수록 잔류 stress가 낮아짐을 확인할 수 있었으며, 향후 후막 GaN 성장 시 stress 감소 가능성에 대해 확인하였다. The characteristics of the residual stress on the types of the substrate was investigated with adjusting the V/III ratio during GaN growth via the HVPE method. GaN single crystal layers were grown on a sapphire substrate and a GaN template under the conditions of V/III ratio 5, 10, and 15, respectively. During GaN growth, multiple hexagonal pits in GaN single crystal were differently revealed in accordance with growth condition and substrate type, and their distribution and depth were measured via optical microscopy(OM) and white light interferometry(WLI). As a result, it was confirmed that the distribution area and depth of hexagonal pit tended to increase as the V/III ratio increased. Moreover, it was found that the residual stress in GaN single crystal decreased as the distribution area and depth of the pit increased through measuring micro Raman spectrophotometer. In the case of GaN growth according to substrate type, the GaN on GaN template showed lower residual stress than the GaN grown on sapphire substrate.

이미지 데이터를 모니터링하는 관리도에서 이미지와 ROI 크기 조정의 영향

이주형,윤형욱,이성민,이재헌,Lee, JuHyoung,Yoon, Hyeonguk,Lee, Sungmin,Lee, Jaeheon 한국통계학회 2017 응용통계연구 Vol.30 No.3

A machine vision system (MVS) is a computer system that utilizes one or more image-capturing devices to provide image data for analysis and interpretation. Recently there have been a number of industrial- and medical-device applications where control charts have been proposed for use with image data. The use of image-based control charting is somewhat different from traditional control charting applications, and these differences can be attributed to several factors, such as the type of data monitored and how the control charts are applied. In this paper, we investigate the adjustment effect of image size and region of interest (ROI) size, when we use control charts to monitor grayscale image data in industry. 최근 산업의 생산공정에서는 머신비전시스템을 통하여 제품의 품질특성치에 대한 정보를 이미지 데이터로 제공하는 경우가 많다. 따라서 산업과 의학 현장에서 이미지 데이터의 모니터링을 위해 관리도 절차의 필요성이 많이 대두되고 있다. 이미지 데이터를 모니터링하는 관리도 절차는 전통적으로 사용하는 관리도 절차와 유사한 점도 있지만, 데이터의 구조를 비롯하여 각 이미지에서 ROI를 설정하여 관리도 절차를 적용하는 등 서로 다른 점도 많이 있다. 이 논문에서는 생산공정에서 제공되는 이미지 데이터에 대해 관리도를 사용하는 절차를 소개하고, 이미지 또는 ROI 크기의 확대와 축소가 제품의 이상원인을 탐지하는데 어떠한 영향이 주는지를 모의실험을 통하여 알아보았고 각 관리도의 성능 또한 비교하였다.

한국고대가람 변천양상에 관한 불교사적 고찰 - 불신관의 발전과 불탑 및 불상의 위상변천에 관한 분석을 중심으로 -

이주형,장석하,Lee, Zu-Hyung,Jang, Suk-Ha 한국건축역사학회 2011 건축역사연구 Vol.20 No.1

It is a true fact that the ancient Buddhist temples of Korea were great, important historical influence revealing the transition and developing stages of all the BUddhist temples in Eastern Asia including China and Japan. Before Mahayana arose within India, the monastery and pagoda were united during the conflict and development of the original Buddhism and pagoda faith. With the arising of Mahayana and the introduction of Buddhist statues, the Buddhist temple and pagoda were in conflict and resulted in separation. With the creation and development of the Mahayana Bodhisattva concept, Hinayana and Mahayana started to show doctrine differences and expressed each others' characteristics relevant to the structure of the temple. As a result, the Buddhist Temple having 1 pagoda spread in China together with Hinayana and Mahayana. The Buddhist temple of Hinayana had its temple and pagoda separated and the Buddhist temple that has a pagoda in front was divided into a form of 1 pagoda and 1 main temple. The temple and pagoda for Mahayana in the form of 1 pagoda and 2 temple, where the main statue of the Buddha may be worshipped from both the left and right hand sides, were separated in the form of 1 pagoda and 3 temples to have its original form again. Mahayana was first introduced into Goguryeo through the routes in the northern region and developed from having 1 pagoda and 2 temples, to having 1 pagoda and 3 temples. China was influenced by the southern regions, which is why Abhidharma was introduced into Baekje. Later on, the importance of Bodhisattva increased and the transition speed of the Buddhist temple having 1 pagoda and 3 temples accelerated, as Buddhism became more popular and as Mahayana flourished. The statue of the Buddha on both sides of the pagoda shall gradually move next to the central temple, and the temple shall form large crowds to not only form a tacit boundary with the pagoda but the expansion of Bodhisattva shall also have a wall or a corridor constructed in between the central, left and right hand side temples to form separate areas, and shall have a pagoda built in front of the temples that worship from both sides. In conclusion, independence shall exist among each Bodhisattva within the Buddhist temple, and the status of the pagoda shall fall and appear as the pagoda on both sides in front of the main Buddha statue.

퍼스컴에 의한 LAN의 구축과 OA의 전개

이주형,Lee, Ju-Hyeong 한국전자정보통신산업진흥회 1984 電子振興 Vol.4 No.4

회원작품 - 건축비평 _ 젊은 아이디어로 '신수동 골목'에 생기를⋯ '풍경을 바꾼' sista house

이주형,Lee, Joohyoung 대한건축사협회 2020 建築士 Vol.613 No.-

주택규모 선택에 영향을 미치는 가구원수별 특성에 관한 연구

이주형,임종현,강남훈,Lee, Joo-Hyung,Lim, Jong-Hyun,Kang, Nam-Hoon 한국주거학회 2010 한국주거학회 논문집 Vol.21 No.2

The housing market requires customized housing to be supplied according to the various characteristics of households. Multinominal Logistic Regression was used to analyze the effects of variables of household characteristics according to the number of family members on the choice of housing size in the scope of the whole country's housing market. Analysis showed that the number of family members has its own characteristics. When a household has a smaller number of family members, there are more variables affecting choice of housing size. Living and housing expenses variables served as significant variables that affect all household types. Results showed that households with more living and housing expenses are more likely to choose a large sized house and where households have a greater number of family members, there is more influence on that choice. The age of the householder was only found to be a meaningful variable in 1-2 person households and 3-4 person households, particularly in the choice of a small or large sized house. This shows that the age of the householder does not play an important role in choosing medium sized houses for households of under 4 people, but affects the choice of small and large sized houses. The academic ability of household members also served as a significant variable. While 1-2 person households with high academic ability tend to select a large sized house, 3-4 person households with high academic ability tend to select a small sized house. It is observed that members of both 1-2 person households and 3-4 person households tend to select their house between a large sized house and a small sized house in order to own their own houses. The result of this research suggests that there are various and detailed variables on the choice of housing size. Especially, a notable result is that household characteristics more significantly affect the housing size choice of 1-2 person households, while the trend of an aging society will more significantly affect a 3-4 person households' choice of a large sized house. Therefore, a study on the choice of housing size according to characteristics of elderly households and 1-2 person households should be continually analyzed.

실트함량에 따른 카올리나이트의 침식특성 평가

이주형,박재현,정문경,곽기석,Lee. Ju-Hyung,Park. Jae-Hyun,Chung. Mun-Kyung,Kwak. Ki-Seok 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1

The scour phenomenon involves the erosive potential of flowing water and the relative ability of the soil to resist erosion. The scour phenomenon in cohesive soils is much different from that in non-cohesive soils. Granular soils resist erosion by their buoyant weight and the friction between the particles. The soil particles are dislodged individually from the bed under the action of the eroding fluid. Scour in cohesive soils is much slower and more dependent on soil properties than that in non-cohesive soils. Therefore the analysis models for estimating erosion characteristics of cohesive soils should consider not only flowing water but also the relative ability of the soil to resist erosion. In this study, erosion characteristics for the clay-silt mixed soil will be analyzed as a fundamental study for development of bridge scour analysis and design system considering scour resistance capacity of a soil. For this analysis, the relationship between scour characteristics and soil properties was evaluated through scour rate test with Kaolinite samples remolded using various loading and contents of silt.

고령 환자의 기존 의치를 치과기공소에서 수리한 증례

이주형,Gyu-Heon Lee 대한치과기공학회 2022 대한치과기공학회지 Vol.44 No.4

The need for repairing removable dentures has grown as the population had aged. The di-rect methods allow existing dentures to be repaired without interrupting their use. However, if patient compliance is low, direct methods may be challenging. Moreover, attaching an ar-tificial tooth to a metal base is a complicated procedure because it necessitates casting a retentive element and soldering it to a metal base. This clinical report describes how to add an artificial tooth to a metal base, reline denture bases, and reestablish occlusion on re-lined removable dentures using indirect methods. Existing removable dentures were suc-cessfully repaired and their service life was efficiently extended using the methods de-scribed.

항재밍/저피탐 웨이브폼이 적용된 군 초소형 위성 통신체계 소개

이주형,박해원,정길수,Ju Hyung Lee,Hae-Won Park,Kil Soo Jeong 한국우주과학회 2023 우주기술과 응용 Vol.3 No.2

The existing military satellite communication system was based on geostationary satellites equipped with special communication payloads against enemy's jamming and signal reception. With the advent of new weapon systems such as unmanned systems, the need for low-orbit satellite-based communication system is increasing. This paper introduces various waveform technologies suitable for cube satellite-based communication system and the operational concept of a future military nanosatellite communication system.

Grafting-onto법에 의한 poly(MMA-co-PEGMA) 전해질의 합성과 이온전도도에 대한 조성의 영향

이주형,류상욱,Lee, Ju-Hyung,Ryu, Sang-Woog 한국전기화학회 2013 한국전기화학회지 Vol.16 No.4

Copolymer consisted of MMA and tBMA was synthesized by radical polymerization and poly(MMA-co-MA) was prepared by selective hydrolysis of tert-butyl group. The obtained polymer was coupled with epoxy functionalized PEO of various molecular weight to synthesize poly(MMA-co-PEGMA) with different side chain length. The AC-impedance measurement shows $1.88{\times}10^{-6}Scm^{-1}$ of room temperature ionic conductivity from 48mol% of MMA while $5.11{\times}10^{-8}Scm^{-1}$ was observed in 82mol% sample. In addition, there was an effect of PEGMA molecular weight on ionic conductivity possibly due to the steric hindrance in grafting-onto coupling reaction. Finally, the polymer electrolytes shows electrochemical stability up to 6V at room temperature. 본 실험에서는 MMA와 tBMA의 공중합체를 합성하고, tert-butyl 그룹의 가수분해를 선택적으로 유도하여 poly(MMA-co-MA)를 제조하였다. 또한 말단에 에폭시기를 함유한 다양한 분자량의 PEO와 MA와의 grafting-onto 커플링 반응을 통해 같은 주사슬을 가지지만 부사슬의 길이가 다른 poly(MMA-co-PEGMA)를 합성하여 조성이 이온전도도에 미치는 영향을 평가하였다. AC-impedance로 측정한 상온 이온전도도는 MMA의 몰분율이 82%에서 $5.11{\times}10^{-8}Scm^{-1}$의 값이 얻어진 반면, 48%에서는 $1.88{\times}10^{-6}Scm^{-1}$로서 많은 PEGMA에서 높게 관찰되었다. 또한 에폭시기를 함유한 PEO의 분자량에 따라 이온전도도의 차이가 발생하는데, grafting-onto 법의 입체적 장애가 원인으로 고려되었다. 한편, 합성된 poly(MMA-co-PEGMA) 고분자 전해질은 상온에서 6V까지 우수한 전기화학적 안정성을 보여주었다.