Light-extraction efficiency control in AlGaN-based deep-ultraviolet flip-chip light-emitting diodes: a comparison to InGaN-based visible flip-chip light-emitting diodes.

Lee, Keon Hwa,Park, Hyun Jung,Kim, Seung Hwan,Asadirad, Mojtaba,Moon, Yong-Tae,Kwak, Joon Seop,Ryou, Jae-Hyun Optical Society of America 2015 Optics express Vol.23 No.16

<P>We study light-extraction efficiency (LEE) of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) using flip-chip (FC) devices with varied thickness in remaining sapphire substrate by experimental output power measurement and computational methods using 3-dimensional finite-difference time-domain (3D-FDTD) and Monte Carlo ray-tracing simulations. Light-output power of DUV-FCLEDs compared at a current of 20 mA increases with thicker sapphire, showing higher LEE for an LED with 250-관m-thick sapphire by ~39% than that with 100-관m-thick sapphire. In contrast, LEEs of visible FCLEDs show only marginal improvement with increasing sapphire thickness, that is, ~6% improvement for an LED with 250-관m-thick sapphire. 3D-FDTD simulation reveals a mechanism of enhanced light extraction with various sidewall roughness and thickness in sapphire substrates. Ray tracing simulation examines the light propagation behavior of DUV-FCLED structures. The enhanced output power and higher LEE strongly depends on the sidewall roughness of the sapphire substrate rather than thickness itself. The thickness starts playing a role only when the sapphire sidewalls become rough. The roughened surface of sapphire sidewall during chip-separation process is critical for TM-polarized photons from AlGaN quantum wells to escape in lateral directions before they are absorbed by p-GaN and Au-metal. Furthermore, the ray tracing results show a reasonably good agreement with the experimental result of the LEE.</P>

The prediction of the tooth size in the mixed dentition for Korean

Moon, Sung-Hwan,Kim, Seong-Oh,Yu, Hyung-Seong,Choi, Byung-Jai,Choi, Hyung-Jun,Lee, Jae-Ho 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.2

이번 연구의 목적은 혼합치열기 아동에서 미맹출된 견치와 소구치의 크기를 예측하는데 있어서 한국인에 맞는 방정식을 만들기 위함이다. 미맹출 치아의 크기를 예측하는 것은 혼합치열기 교정 진단과 치료계획 수립에 있어서 매우 중요하다. 미맹출된 견치와 소구치 크기를 예측하는 방법은 몇가지가 있지만 그중에서도 가장 흔하게 쓰이는 것이 모이어의 예측표와 다나카와 존스턴의 방정식이 있다. 하지만 그것들은 백인을 위해서 제작된 것이고 치아 크기는 인종에 따라서 다르다고 알려져 있다. 이번 연구에서는 치아크기를 측정하여 하악 영구 절치의 크기 합과 견치 및 소구치의 크기 합 사이의 상관관계를 구하고 회귀방정식을 이용해서 한국인에 맞는 예측표를 만들었다. 연세대학교 치과대학에 재학중인 178명의 한국 학생(남 108명, 여 70명, 평균연령 21.63)을 대상으로 실험하였다. 영구치의 근원심 폭경을 석고모형상에서 calipers를 이용해서 측정하였다. 성별간의 치아 크기는 차이가 있었다(p<0.05). Correlation coefficient는 0.57에서 0.64의 범위였고, standard errors of the estimates 는 여성에서 0.6으로써 남성보다 우수하였다. r^(2)값은 0.27에서 0.41의 범위를 나타내었다. Estimating the size of unerupted teeth is an essential aspect of orthodontic diagnosis and treatment planning in the mixed dentition. Several methods were introduced and used for the prediction. The most common methods among these would be Moyers probability chart and Tanaka and Johnston equations. These are currently used widely, but they were developed for Caucasians. Because there are clear racial differences in teeth size, the objectives of this study were to produce correlation coefficients between the combined mesiodistal widths of the permanent mandibular incisors and those of the canines and premolars for each quadrant, and prediction tables with regression equations, specifically for Korean. 178 young adults (70 women, 108 men, mean age 21.63 years) were selected from the College of Dentistry, Yonsei University, Seoul, Korea. The mesiodistal crown diameters of the permanent teeth were measured with calipers. Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and those of the maxillary and mandibular canines and premolars were found to be between 0.52 and 0.64. The standard error of the estimatation was better (0.60) for women and the r^(2) values ranged from 0.27 to 0.41 for both sexes, Prediction tables were prepared for Korean. This study showed larger canine and premolar diameters than Tanaka and Johnston's and Moyers' studies which might be due to the racial differences. Further investigations with a larger sample size will be needed for more representative data on the Korean population.

만성 신부전을 동반한 Laurence Moon-Bardet Biedl 증후군 1례

박래경,이동환,문철,김은미,Park Lae Kyong,Lee Dong Hwan,Moon Chul,Kim Eun Mi 대한소아신장학회 1998 Childhood kidney diseases Vol.2 No.2

The Laurence Moon-Bardet Biedl syndrome is characterized by obesity, mental retardation, visual impairment with retinitis pigmentosa, polydactyly, hypogonadism and renal manifestations. We experienced an 11 years old female with Laurence Moon-Baret Biedl syndrome associated chronic renal failure. She was diagnosed to have LMB syndrom according to the clinical manifestations of polydactyly on hands and feet, mental retardation, obesity, retinitis pigmentosa and chronic renal failure. She is on maintenance hemodialysis now.

Sarcomatoid Carcinoma Arising from Mature Cystic Teratoma

Ho-Chang Lee1, Seung-Myoung Son, Yong-Moon Lee, Ji Hae Koo, Song-Yi Choi, Ok-Jun Lee, Eun-Hwan Jeong 충북대학교 동물의학연구소 2012 Journal of Biomedical and Translational Research Vol.13 No.2

Malignant transformation of mature cystic teratoma (MCT) is rare. Sarcomatoid carcinoma is a neoplasm comprising malignant mesenchymal cells and a conventional carcinomatous area. Here, we report on a case of sarcomatoid carcinoma arising from an MCT in the left ovary of a 45-year-old female. A unilocular cyst consistent with MCT was observed; however, a nodule within the cyst was confirmed from the resected ovary. Microscopically, the nodule showed both squamous cell carcinoma and pleomorphic sarcomatous components admixing with each other. Lining epithelial cells at the periphery of the main tumor showed squamous metaplasia. When a sarcomatous component is observed in the ovary tumor, it is important to find a squamous cell component, either benign or malignant.

건설현장 근로자들의 안저예방실태와 사고예방과의 개선요인 조사연구

심규범,남철현,최상복,이송권,이정희,이순자,문기내,김문환 慶山大學校 保健福祉硏究所 2003 保健福祉硏究 Vol.8 No.-

This study was conducted to examine aspects of health and safety education and demand level of safety education in construction job sites in order to provide direction of safety education development. The subjects of this study were 566 workers who were working in construction job sites located in Daegu City and Kyungbuk Province. Data were collected from June 1, 2002 to August 30, 2002. The results of this study can be summarized as follows. 1. According to safety education by experience methods, the proportion of education by lecture was highest (90.6%). The proportion of education by field practice was 13.1%. 2. Among the education methods which they thought as the most desirable method, the proportion of audio-visual education was 39.4% and the proportion of education by experience was 37.5%. Those who had more monthly income and higher education level preferred audio-visual education, while those who were younger and less educated preferred education by experience. 3. In the case of the contents of the safety education which they thought as the most important one, the proportion of enhancement of safety awareness and education of risk factors was highest (24.7%). The groups of older workers, having longer working period, and belonging to higher education level preferred these contents. 4. According to the factors which were most important to increase effectiveness of the safety education were workers' voluntary participation (27.7%), 40 to 49 years old (27.7%), and monthly income of one million, five hundred thousand won to one million, nine hundred ninety thousand won (32.0%). The proportions of lower educated workers and working as daily workers were also high. 5. The variable which most influenced the safety education was age. The safety awareness of construction job sites was the second highest influential variable. From above results, it is clear that the workers' participation in the safety education was low since most of the safety educations were formal education by lecture. Although they participated in the education, the education was also not effective because they compulsorily participated in it. Therefore, it can be concluded that effective alternative policies must be formulated.

뇌 실질 출혈이 동반된 Reye 증후군 1례

이창연,오연희,임문환,유문집,박성기,김태우 동국대학교 경주대학 1991 東國論集 Vol.10 No.-

Reye syndrome is a disorder of unknown etiology in which a child recovering form a viral prodrome suddenly develops pernicious vomiting & eventually develops neurologic changes. The syndrome is defined to acute noninflammatory encephalopathy with fatty degeneration of liver and other organs. The coagulopathy or Reye syndrome is associated with proloned PT caused by the mitochondrial injury compromising synthesis of proteins and clotting factors in liver. In this case, we observed ICH on right parietal and occipital area in brain CT. Actually, bleeding in the major organ is extremely rare in Reye syndrome, this may be the first case report of CNS bleeding in Korea associated with Reye syndrome. In addition to case report, we present a brief review of the related literatures.

한국 사회체육의 현황과 과제

이제홍,이광수,박문환 순천향대학교 기초과학연구소 1998 순천향자연과학연구 논문집 Vol.4 No.2

This paper examined current state and issaue of sport for all in Korea relevent problems in promting sports organizations, facilities, sports coaches and athletic programs. This suggestions of this study as follows. First, organizations to support social sports and athletic activities should be unified in other to avoid duplicate investment in sports business and service. Second, for the sake of to make better organizations are to meet many-sided desires of the people for sports and athletic activities, the quantitative expansion and the qualitative improvement of public or private athletic facilities, the opening of school athletic instruments and facilities, and the systematization of the management and financial support of social sports facilities are inevitably demanded. and developed ought to be established. Moreover effective sport program and the proper programs must be maintained. Third, increasing efforts should be plused upon developing, systematic education programs forl sports coaches and specialists, their effective appointment and disposition, and the improvement of their working conditions in order to raise specially in social sports adminstration. Finally, for the better programming, in quantity, of the sports for all proper structure or organization in which diverse sports for all program can be.

Weissenberg 寫眞 技法에 의한 酸化마그네슘(MgO)의 結晶構造

이진호,류보영,조소라,김문집,추금홍,서일환,임성수 순천향대학교 1993 논문집 Vol.16 No.3

The structure of MgO crystal is faced centered cubic(FCC) with cell parameters of a=b=c=4.21Å, α=β=γ=90。. The ionic bond length between Mg and O atoms is 2.1Å. This crystal belongs to m3m point group and to Fm3m space group.

도로 연속교에서 최대 활하중모멘트의 공식화에 관한 연구

李元福,文桓斗 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.4 No.-

Continuous-beam bridges may be analyzed in a very concise manner for situations of constant-flexural stiffness(EI), symmetrical structures with interior spans of equal length. When load is applied to only one span, all end moments may be directly determined from simple calculations using coefficients derived on the basis of the compatibility of joint rotations, without simultaneous equations. Results from mulitple loads in several spans may then be obtained by superposition. Closed-from expressions are presented herein for end moments in continuous beams with three spans. Practical applications of the method are illustrated by providing closed-form expressions for (+), (-) maximum moments caused by lane load and vehicle load in continuous beam highway bridges.

척추관 협찬증 환자 진료 프로세스 개발

이환모,김호중,김긍년,안풍기,천자혜,김양수,신혜선,김인숙,정혜경,김영아,채형기,박인영 한국의료QA학회 2009 한국의료질향상학회지 Vol.15 No.2

연구배경: 수술적 치료가 필요한 척추관협착증 환자들은 주로 60세 이상의 고령환자로장기간의 입원 시 기회 감염의 증대와 불필요한 의료비의 증대를 가져오게 되며, 수술후환χ}들의 재원일수의 증가는병원의 병상가 동률을감소시키고, 전공의에게는불필요한 업무를 증가시킨다. 연구목적: 비용·효과면에서 최적화된 진료지침의 개발은 불필요한 의료비의 감소및 Hospital Induced Complication을 줄여 환자만족도를증진시킬 수 있으며, 각 환자에 대한전공의 업무를 줄일 수있다. 의료기관: 서울특별시에 소재한 2,075병상의 종합전문 요양기관 연구방법: 정형외과및 신경외과의 척추관협착증환자 의 처방을 비교하여 최적의 표준진료지침을 개발하고 최종적으로 CP Master Program (EMR 프로그램)에 입력하여 환자에게 적용하였다. 연구결과': CP 적용전, 후비교를통해 재원일수는 3.8일 이 감소하였으며, 이에 따라 병상가동률 및 진료수익이 증가했으리라고 예상되며 현재 비교검토중이다. 또한,CP 개발및 CP Master Program의 사용을 통한 전공의 업무감소에 대해 검토하고 있다.