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.

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.

스펙트럼 상관관계를 이용한 ATSC 지상파 DTV의 고속 주파수 동기 방법

이주형,송현근,남완주,김재명,김승원,Lee Joo-Hyung,Song Hyun-Keun,Nam Wan-Ju,Kim Jae-Moung,Kim Seung-Won 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.9a

본 논문에서는 ATSC 지상파 DTV 시스템에서 스펙트럼 상관관계를 이용한 주파수 동기 방법을 제안한다. 파일럿 신호를 이용하는 기존 알고리즘은 다중경로와 이동수신 환경에 의해 파일럿 주변의 스펙트럼 왜곡이 심하면 주파수 옵셋 추정 오류가 발생한다. 제안하는 알고리즘은 파일럿을 사용하지 않고 기준 스펙트럼과 수신된 스펙트럼 사이의 상관관계를 이용하여 주파수 동기를 획득하기 때문에 기존의 동기 방식에 비해 빠르고 정확하게 주파수 동기를 획득할 수 있다. 또한 파일럿을 사용하지 않는 새로운 ATSC 주파수 동기 방식을 제시한다. This paper proposes the method of frequency synchronization using the spectrum correlation in ATSC terrestrial DTV system. If the spectrum around pilot is severely distorted by multipath or mobile reception environment, the conventional algorithm using the pilot signal makes the estimation error of the frequency offset. Because the proposed algorithm acquires frequency synchronization using the correlation between the received specalm and the standard spectrum without the use of pilot, the proposed method can acquire frequency synchronization faster and more accurate than conventional algorithm. And this paper proposes new method for ATSC frequency synchronization without the use of pilot.

노후 콘크리트 구조물의 실용적 유지관리를 위한 콘크리트 구조물 안전진단 지침 분석

이주형,조재열,Lee, Joo-Hyung,Cho, Jae-Yeol 한국토지주택공사 토지주택연구원 2020 LHI journal of land, housing, and urban affairs Vol.11 No.3

In South Korea, problems caused by material deterioration of time-worn concrete structures have been increased recently. Because severe material deterioration could damage the structure's safety, it's important to evaluate the old structure's condition and structural capacity regularly to keep its proper performance. The safety evaluation of concrete structures has been initiated and performed periodically since 1995 according to a guideline in accordance with a law in Korea. The guideline prescribes the evaluation types, intervals and methods of the target structure. A lot of cost and labor have been invested every year to carry out the regular safety evaluation. However, it's not clear that the current manual could inspect the old structure's condition and assess the structural capacity precisely. Thus, the verification study initiated to figure out the Korean safety evaluation manual's practicalness. First, the Korean manual was analyzed and then compared with that of other countries for concrete bridges which are representative concrete structure. After that, the previously written evaluation reports were collected and analyzed to find out how the safety evaluation has been carried out. Based on the study results, the parts requiring verification of the manual were drawn. A research program is in progress in order to verify the parts by performing tests with actual structural members from decommissioned concrete bridges.

전방십자인대 손상으로 인한 슬관절 불안정성에 따른 경골 골단 해면골 미세구조 변화 : 내방과 외방에서의 해면골 미세구조 패턴 변화

이주형,전경진,김한성,임도형,Lee, Joo-Hyung,Chun, Keyoung-Jin,Kim, Han-Sung,Lim, Do-Hyung 대한의용생체공학회 2012 의공학회지 Vol.33 No.2

Knee joint instability by anterior cruciate ligament(ACL) rupture is allowing the abnormal loading condition at the tibial epiphysis locally, resulting in producing locally different bone bruise. The study examined difference between local alteration patterns of trabecular bone microarchitecture at medial and lateral parts of the tibial epiphysis by ACL rupture. Fourteen SD rats were divided into Control(CON; n = 7) and Anterior Cruciate Ligament Transection(ACLT; n = 7) groups. The tibial joints were then scanned by in vivo ${\mu}$-CT at 0, 4, and 8 weeks post-surgery. The results showed that alteration pattern on trabecular bone microarchitecture at medial part was significantly higher than that at lateral part of the tibial epiphysis in ACLT group from 0 to 8 weeks(P < 0.05). Tb.Th and Tb.Sp distributions were well corresponded with differences between aforementioned trabecular bone microarchitectural alteration pattens at medial and lateral parts of the tibial epiphysis in ACLT group from 0 to 8 weeks(P < 0.05). These findings suggest that the alteration patterns of trabecular bone microarchitecture should be locally and periodically considered, particularly with respect to the prediction of bone fracture risk by ACL rupture. Improved understanding of the alteration patterns at medial and lateral trabecular bone microarchitectures at the tibial epiphysis may assist in developing more targeted treatment interventions for knee joint instability secondary to ACL rupture.

국내 브랜드 아파트 단위세대의 무장애 수준에 관한 연구

이주형(Lee Joo Hyung),김준연(Kim Jun Yeon),강병근(Kang Byoung Keun) 한국장애인재활협회 2015 재활복지 Vol.19 No.2

본 연구는 최근 주거공간에서의 무장애와 정주성에 대한 중요성이 부각되면서, 이에 대한 대응 방안을 찾고자 하였다. 이를 위해 국내외 관련 기준의 비교분석과 현재 공급되고 있는 공동주택의 무장애 수준을 분석하였다. 연구결과 독일, 영국, 미국, 일본, 한국의 무장애 주택관련 기준을 분석하여 무장애 수준(BF)과 휠체어 이용가능 수준(BF-W)으로 구분된 무장애 주택 기준을 도출하였다. 이를 바탕으로 국내 도급순위 상위 5개 건설사 아파트 단위세대의 무장애 수준을 살펴보았고, 도출된 기준대비 국내 아파트의 BF수준은 50%내외, BF-W수준은 30%내외인 것으로 나타났다. 주택 내 작동설비, 위생설비, 벽체의 구조적 성능 등을 개선 한다면, 더 높은 적합률을 보일 것으로 보여, 도출된 BF수준의 기준은 일반 주택에도 적용 가능한 것으로 나타났고, 공간규모 확대가 필요한 BF-W수준의 기준은 일정 비율의 휠체어 장애인을 위한 주택에 적용 가능한 것으로 나타났다. 향후 다양한 주거 유형의 수준도 함께 검토하여 보편적으로 적용 가능한 기준 개발 연구가 지속되어야 할 것이다. The recent research has emphasized the importance of the barrier free and aging in the place in the housing space. Thus, the present study looked at alternative ways to improve the planning criteria and the relevant system. To do this, the comparative analysis is conducted, by comparing criteria used in domestic as well as foreign areas and by analyzing the circumstance of barrier free in apartments given. The present study established the criteria which distinguish the levels of the barrier free and the accessibility of wheelchairs, through the analysis of barrier free housing criteria used in Germany, UK, USA, Japan, and Korea. Based on this, this study reviewed all circumstance of barrier free in apartments. The results showed the appropriate rates less than 30% of BF-W and 50% of BF. It seems possible that suggested standard of BF can be applicable to housing and the standard of BF-W is applicable to housing for the wheel-chaired people, if the improvement within apartments occurs. Through review various housing-types, further research should be continued for the general standard, which is possibly applicable.

입지별 주상복합 개발 특성에 관한 연구

이주형(Lee, Joo Hyung),채두병(Chae, Du Byeong),박희수(Park, Hee Soo) 韓國不動産學會 2010 不動産學報 Vol.41 No.-

1. CONTENTS (1) RESEARCH OBJECTIVES The purpose of this study is to analyze the spatial characteristics of mixed residential? commercial developments in Seoul (2) RESEARCH METHOD The characteristics of development according to locations are deducted by principle analysis and the results are verified through the ANOV A analysis (3) RESEARCH FINDINGS housing←commercial development is very important by the aspect of urban planning as a result of functioning to each simple architectural development as well as deciding the direction of urban development and urban spatial structure m existing cities 2. RESULTS the result from this research which analyses the characteristics of location based housing-commercial development demonstrates that the housing-commercial development in Seooul presents refleιting the characteristics of each architectural plan rather than realizing the direction of housing commercia development. Therefore, the legislation is urgently required because there is a possibility to expand housing-cαnmercial development later in the case of Seoul whose existing cities have been deterioration. In addition to this, it is necessary to nnprove accαnmodating the complex of three dimensional land use as conceming an exclusive zoning system.

폐교량 부재를 활용한 공용 중 콘크리트교 구조성능평가

이주형(Lee, Joo-Hyung),이현송(Lee, Hyun Song),이겨레(Lee, Kyeo Re),박재현(Park, Jae Hyun),조재열(Cho, Jae-Yeol) 한국콘크리트학회 2020 한국콘크리트학회 학술대회 논문집 Vol.32 No.2

메타버스를 활용한 무용교육 적용 가능성 탐색

이주형 ( Joo Hyung Lee ),문영 ( Young Moon ) 대한무용학회 2023 대한무용학회논문집 Vol.81 No.1

The purpose of this study is to explore the applicability of metaverse technology to dance education. This study analyzed the case in which metaverse technology was used as arts education at a time when the integration of technology and education was expanding. Based on this, the author tried to propose a dance education program using metaverse. After selecting three art education programs using metaverse, this study explored planning plans and interviewed focus groups as program participating instructors to explore planning intentions and specific examples. Based on this, this research presented a step-by-step curriculum for dance education programs that learn Korean and Italian mask dances in virtual spaces by manipulating avatars using the Mirror Worlds and Virtual Worlds in the form of metaverse. This study will be significant as a basis for exploring the possibility of linking technology and art, and for the continued spread of research. Based on this study, this author expects that the metaverse technology will be utilized in various aspects of dance education as well as integrated dance education, and it will contribute to the application of future metaverse platforms.

폐콘크리트교 부재 실증실험 결과 분석 및 콘크리트교 안전진단 매뉴얼 검증

이주형(Lee, Joo-Hyung),이현송(Lee, Hyun Song),유용재(Yu, Yong Jae),안혁준(Ahn, Hyuk Jun),조재열(Cho, Jae-Yeol) 한국콘크리트학회 2019 한국콘크리트학회 학술대회 논문집 Vol.31 No.2