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      • 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>

      • KCI등재

        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.

      • KCI등재후보

        저등급 자궁내막 간질성 육종 3예

        고선환,송은섭,김세련,이문희,김우철,송윤섭,박지현,임문환,이병익,이우영 대한산부인과학회 2004 Obstetrics & Gynecology Science Vol.47 No.4

        저등급 자궁내막 간질성 육종은 자궁의 악성종양 중에서 단지 0.2%를 차지하는 매우 드문 질환으로, 세포분열의 활성도에 따라 고등급과 저등급으로 나뉘어진다. 저자들은 3예를 경험하였기에 면역조직화학 염색 진단과 질환의 진행 정도에 따른 치료를 간단한 문헌 고찰과 함께 보고하고자 한다. Endometrial stromal sarcomas (ESS) of the myometrium compose just 0.2% of uterine malignant tumors. In terms of their cellular mitotic activities, they are named as low grade or high grade ESS. As low grade ESSre very rare, we would like to report our 3 cases with immunohistochemical stain method, treatment option as the disease progression and the brief review of literature.

      • KCI등재후보

        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.

      • KCI등재후보

        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.

      • 액체막법에 의한 중금속이온의 분리 및 회수

        曺文換,丁學鎭,이상인,金振浩,金始中 江原大學校 附設 環境硏究所 1994 環境硏究 Vol.11 No.-

        거대고리 리간드는 금속이온과 선택적으로 결합하는데, 이를 이용하여 에멀젼 액체막을 통한 금속이온의 이동에 관하여 연구를 수행하였다. 금속이온은 유기층에 있는 운반체에 의하여 source phase에서 receiving phase으로 이동한다. 운반체로는 거대고리 리간드인 DBN_(3)O_(3)를 사용하였다. 여기에서 에멀젼 액체막을 통한 금속이온의 이동에 관한 요인과 어떤 금속이온의 선택적 분리에 관하여 검토하였다. 금속이온과 거대고리 리간드 그리고 금속이온과 receiving phase내에 있는 음이온에 대한 안정도 상수를 금속이온의 선택적 이동에 대한 척도로 조사하였다. 납이온이 혼합 용액에서 다른 금속이온보다 높은 이동속도를 나타내었다. Receiving phase내의 음이온이 금속이온의 이동에 중요한 역할을 한다. Receiving phase내에 있는 NO_(3)^(-)을 S_(2)O_(3)^(2-) 대치하면 이동량이 증가함을 보였는데 이는 Pb^(2-)-S_(2)O_(3)^(2-) 상호작용이 Pb^(2+)-NO_(3)^(-) 상호작용보다 크기 때문이다. Macrocyclic ligand has been know to selectively bind with metal ions so that ability applied for the transport of metal ions across the emulsion liquid membrane in this study. The metal ions are transproted from the source phase to the receiving phase by the carrier of the organic phase. Several factors involved in the transport of metal ions acrose the emulsion membrane we reported here and these factors proveided the informations for the selective seperation of some metal ion. Stability constants for cation-macrocyclic ligand and metal ion-anion receiving phase interaction are examined as parameters for the prediction of metal ion transport selectivities Pb^(2+) was transported higher rates than the other metal ions in the mixture solution. The interaction of metal ion to anion in receiving phase is important. S_(2)O_(3)^(2-) in replacement of NO_(3)^(-) in the receiving phase enhances the transport of pb^(2-) since Pb^(2-)-S_(2)O_(3)^(2-) interaction is greater than Pb^(2+)-NO_(3)^(+) interaction.

      • 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.

      • 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.

      • 點郡 3㎖(H) 의 振動寫眞 및 Weissenberg寫眞에서의 特性

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

        Crtstallographic cell constants of point group ?? are a =b≠c, α=β=90。, and γ=120。. There are mirror plane symmetries in oscillation photography taken at a-axis and b-axis, but no plane symmetry at c-axis. Since Weissenberg zeroth layer taken at a- and b-axis obeys Friend's law, half of the photography shows non-symmetric unit of diffraction intensity. There are 6 mirror planes in the Weissenberg zeroth layer when the photography was taken at c-axis, therefore 1/12 of the unit cell is non-symmetric unit.

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