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>

수학자 보재 이상설(李相卨)의 근대자연과학 수용 -『백승호초(百勝胡艸)』를 중심으로-

이상구 ( Sang Gu Lee ),박종윤 ( Chong Yun Park ),김채식 ( Chae Sik Kim ),이재화 ( Jae Hwa Lee ) 한국수학교육학회 2013 수학교육논문집 Vol.27 No.4

본 논문은 한국 근대수학교육의 아버지 이상설(李相卨, 1870-1917)이 자연과학―물리학―에 기여한 내용을 다루고있다. 이상설은 ?수리(數理)?를 쓴 시기를 전후하여, 같은 시기에 붓으로 총 8면에 걸쳐 『백승호초(百勝胡艸)』라는이름의 고전물리학 원고를 써서 남겼다. 분석결과 이 책의 원전은 1879년에 동경제대 의학부 교재로 발간된 『물리학(物理學)』이다. 이상설은 『백승호초』에서 먼저 개념을 정의하고, 일상에서 나타난 대표적 현상을 선록하여 한문으로번역하였고, 『물리학』의 전체 분량에서도 특히 ‘통유성(通有性)’에 중점을 두고 설명하였다. 동양에서 서양의 수리과학이 들어와야만 말할 수 있는 ‘질량보존의 법칙’, ‘타성(惰性, 관성)’과 같은 고전물리학의 중요개념을 포함하는 내용이 19세기 말에 이미 이 책에 소개된 것으로 보아 이상설은 당대의 다른 저술에서 보기 힘들 정도로 당시 일반물리학의 최고수준의 원서를 통해 최신 정보를 수용하고 전파하기 위하여 노력하였음을 볼 수 있다. Sang-Seol Lee(1870-1917) wrote a manuscript BaekSeungHoCho(百勝胡艸) in the late 19th century. BaekSeungHo-Cho was transcribed in classical Chinese from the 1879 Japanese book Physics(物理學) by Teizo Ihimori (1851-1916). Sang-Seol Lee, a famous independence activist, is also called Father of the Modern Mathematics Education of Korea,because of his early contribution to the modern mathematics education in the 19th century. In this paper, we introduce contents of his manuscript BaekSeungHoCho for the first time and discuss the significance of this book. Also, we show his constribution on the introduction to modern physics in the late 19th century Korea.

수학자 이상설이 소개한 근대자연과학: <식물학(植物學)>

박영민 ( Young Min Park ),김채식 ( Chae Sik Kim ),이상구 ( Sang Gu Lee ),이재화 ( Jae Hwa Lee ) 한국수학교육학회 2011 수학교육논문집 Vol.25 No.2

본 원고는 2004년 과학사학자 박성래 교수가 독립 운동가이자 한국 근대 수학교육의 아버지로 부르기 시작한 보재 이상설(李相卨, 1870-1917)이 자연과학에 기여한 내용을 다루고 있다. 한국수학사학회지 2009년 11월 호에 자세히 소개된 〈數理〉를 쓴 시기를 전후하여, 같은 시기에 이상설이 붓으로 쓴 것으로 여겨지는 〈植物學>(이상설, 1899)은 총 4면의 초록 필사본이며, 그 대본(臺本)은 〈植物學啓蒙〉 (Edkins, 1886)으로 영국의 Joseph Edkins(艾約瑟, 1823-1905)가 번역하여 1886년에 간행한 〈西學啓蒙〉 16종 가운데 하나이다. 이상설의 〈植物學>은 이 〈植物學啓蒙〉을 읽으면서 그 책의 내용 중 당시의 조 선 학자가 모르고 있던 새로운 내용을 중심으로 메모를 한 것으로 여겨진다. 본 연구에서는 전통산학과 근대서양수학을 연결하는 〈數理〉를 저술했으며. 우리나라의 정규 교과과정에 수학과 과학을 필수과목으로 지정하고, 첫 번째 수학교과서 〈산術新書〉를 발간함으로 당대 최고의 수학자로 평가된 이상설이 쓴 〈植物學〉을 발굴하여 그 내용과 의미를 최초로 분석한다, 이를 통하여 당시 조선의 서양 과학, 특히 식물학에 대한 이해 수준을 분석하고 〈植物學〉의 원전인 〈植物學啓蒙〉 과 <西學啓蒙〉의 저자에 대하여 알아본다. 이는 당시 수학교육자가 자연과학분야에 행한 교육적 기여를 이해 하는데 필수적인 연구이다. This paper deals with contents that Sang-Seol Lee contributed to the natural science in the 19th century Korea. Prof. Sung-Rae Park, the science historian, called Sang-Seol Lee Father of the Modern Mathematics education of Korea. Sang-Seol Lee wrote a manuscript Botany with a brush in late 19th century. Botany was transcribed from Science Primers: Botany (written by J. D. Hooker), which is translated into Chinese by Joseph Edkins in 1886. The existence of Sang-Seol Lee`s book Botany was not known to Korean scientists before. In this paper, we study the contents of Botany and its original text. Also we analyze people`s level of understanding Western sciences, especially botany at that time. In addition, we study authors of 16 Primers for Western Knowledge. We study the contribution of mathematician Sang-Seol Lee to science education in the 19th century Korea.

2003년 국내 중증급성호흡기증후군 진료 현황 및 문제점 분석

이진수,김은실,정문현,백제중,정선화,안주희,최영화,이선희,고철우,김성범,김민자,박승철,기현균,송재훈,최상호,김양수,이상오,조용균,박영훈,정숙인,김연숙,이흥범,손창희,장성희,정희진,김우주 대한감염학회 2004 감염과 화학요법 Vol.36 No.3

목적 : 2002년 말 중국에서 SARS가 발생한 이후 국내에서도 2003년 10월까지 총 3명의 추정환자, 17명의 의심환자가 보고되었다. 향후 추가적인 SARS의 유행이 우려되는 상황에서, 그간의 SARS 환자 진료에 있어서의 실질적인 준비사항, 진료 현황 등에 대한 조사를 통해 문제점을 파악하여, 향후 더 나은 대비가 될 수 있도록 개선점을 제시하고자 하였다. 재료 및 방법 : SARS로 의심되는 환자를 진료 경험이 있는 병원의료진을 대상으로 2003년 10월에 설문조사를 실시하였다. 설문에는 SARS 환자 진료 시의 실질적인 조치, 진료 현황, 병실, 응급실 및 외래에서의 격리 시설과 준비사항, 보건당국의 관리와 지원에 관한 사항을 포함하였다. 결과 : 대상이 되는 22개 병원 중 17개(17/22, 77.2%) 병원이 설문에 응하였다. SARS 환자를 위한 격리실은 응급실, 외래, 일반병실 및 중환자실에서 각각 9개(9/17, 52.9%), 5개(5/17, 29.4%), 15개(15/16, 93.7%), 4개(4/16, 25%) 병원에서 음압처리가 되어있지 않은 일인실 혹은 다인실이 사용되었고, 1개(1/16, 6.3%) 병원에서만 일반병실에서 음압격리실이 운영되었다. 입원환자의 진찰 시 개인보호구의 착용은 거의 모든 의료기관에서 이루어졌다. 보건당국에서 SARS지정병원의 시설 등을 사전에 확인한 곳은 1곳(1/12, 8.3%)이였고, 14개 병원(14/15, 93.3%)에서는 보건당국에 의뢰한 검사결과를 통하 받지 못하였다. 결론 : 의료기관에서 SARS 환자용 격리실뿐만 아니라 기존의 격리실 설비 등이 미흡하였으며, 특히 중환자실 및 외래의 준비가 더욱 부족하였다. 보건당국의 의료기관에 대한 종합적인 지원이 부족하였고, 병원과의 원활한 연계가 잘 이루어지지 않았다. SARS 만이 아닌 격리를 필요로 하는 질환의 적절한 진료를 위해 향후 병원 시설의 정비와 정부차원에서의 보다 구체적이고 실질적인 대책마련이 필요하다. Background : There was an worldwide outbreak of the Severe Acute Respiratory Syndrome (SARS) originated from China in late 2002. During that period three cases of suspected SARS and 17 cases of probable SARS were reported in Korea. With the concerns about the reemergence of SARS-coV transmission, it is important to be prepared for any possibility. So, this study is aimed to analysis the past measures in managing SARS and propose the amendatory plans to improve the preparedness. Materials & Methods : Questionnaires were collected among clinicians with any experience in managing the probable or suspected SARS cases in Oct. 2003. 17 out of 22 hospitals responded to the questionnaire. The contents in the questionnaire were practical activities, personal equipments, response plans, isolation facilities in emergency centers, outpatient clinics, general wards and intensive care units, and relationship with the public health department. Results : The dedicated isolation rooms in emergency centers, outpatient clinics, general wards, and intensive care units were prepared in 9 (9/17, 52.9%), 5 (5/17, 29.4%), 15 (15/16, 93.7%), and 4 (4/16, 25.0%) hospitals, respectively. Except for one hospital that newly made negative pressure room for SARS, single or multi-bed rooms without airborne infection control were used in all the other hospitals. The personal precaution principles were kept quite well in general wards. Before the designation of SARS hospital by the public health department prior evalution to see if the hospital was suitable for managing SARS was conducted in only 1 (1/12, 8.3%) hospital. The results of laboratory diagnosis were reported back in 1 (1/15, 6.6%) hospital. Conclusions : The isolation facilities which can control airborne infection were almost deficient not only for SARS but also for other respiratory transmissible diseases. For the infection control of transmissible diseases including SARS, more investment is needed on medical facilities and comprehensive support from the public health department required.

내시경적 조직검사로 진단된 위 분선충증 1 예

이석호,이화영,이규택,강인구,최규완,백승운,이종균,이준혁,고광철,이종철,오영륜,현재근,이풍렬,김재준,채종일 대한소화기내시경학회 1999 Clinical Endoscopy Vol.19 No.2

Strongyloidiasis is a parasitic disease caused by Strongyloides stercoralis which exists in two forms : the free living and parasitic forms. It exists in warm, moist climate in areas where there is frequent fecal contamination of the soil. After cutaneous invasion by the filariform larvae, petechial hemorrage, pruritus, papular rashes, edema, and urticaria occur. Infection commonly occurs in the proximal intestine of the gastrointestinal (G-I) tract but may extend from the stomach to the anus. Once the worm is established in the small intestine, the physical findings may include epigastric tenderness to palpation. The mucosal biopsy is an inefficient way of making the diagnosis because the worm is found in the biopsy specimen in only 2% of patients. Gastric strongyloidiasis is rare. We experienced a case of gastric strongyloidiasis diagnosed by the endoscopic biopsy and serologic test for parasite specific IgG antibody by micro-ELISA.

Correlation Between Primary Si and Silicide Refinement Induced by Ultrasonic Treatment of Multicomponent Al–Si Alloy Containing Ti, Zr, V, and P

Jae‑Gil Jung,Young‑Hee Cho,Tae‑Young Ahn,Jae‑Hee Yoon,Sang‑Hwa Lee,Jung‑Moo Lee 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

The correlation between primary Si and silicide refinement induced by ultrasonic treatment (UST) of multicomponent Al–Sialloy containing Ti, Zr, V, and P was investigated. UST significantly refined the primary Si phase owing to cavitation-inducedwetting and deagglomeration of MgAl2O4particles. Lowering the UST finish temperature caused deterioration of the degreeof primary Si refinement, instead leading to silicide refinement. Cavitation-induced silicide nucleation on wetted MgAl2O4consumed the MgAl2O4particles, particularly in the case of primary Si nucleation. Similarly, the formation of an AlP phaseon the silicide phase reduced the nucleation efficiency of the AlP phase. Poisoning of the MgAl2O4and AlP phases by thesilicide phase was responsible for the deterioration in primary Si refinement. Room-temperature tensile strength and hightemperatureelongation were increased by UST and were dependent on the size of primary Si.

배양상태의 흰쥐 뇌하수체 앞엽에서 Neuropeptide Y 함유세포에 관한 면역조직화학적연구

이화영,김순회,이희래,어환,이왕재,백상호,이병란 대한해부학회 1996 Anatomy & Cell Biology Vol.29 No.3

생약추출물 유도형 Nitric Oxide Synthase 저해활성 검색

류재하,이소영,박재현,이화진,장세란,은진희,김남이,정연수,장미경,최영은,이숙현,손행자,안한나,고혜진 숙명여자대학교 약학연구소 2001 약학논문집-숙명여자대학교 Vol.17 No.-

Nitric Oxide (NO), derived from L-arginine, is produced by two types (constitutive and inducible) of nitric oxide synthase (NOS: cNOS and iNOS). The NO produced in large amounts by the iNOS is known to be responsible for the vasodilation and hypotension observed in septic shock and inflammation. The inhibitors of iNOS, thus, may be useful candidate for the treatment of inflammatory diseases accompanied by the overproduction of NO. We prepared alcoholic extracts of herbal drugs which have been used for the treatment of inflammation in oriental medicine. We have screened the inhibitory activity of NO production in lipopolysaccharide (LPS)-activated macrophages after the treatment of these extracts. Among the 81 kinds of extracts of herbal drugs, 34 extracts showed potent inhibitory activity of NO production above 50% at the concentration of 50 (μg/ml. The inhibitory activities of NO production were also evaluated for several solvent fractions at three different concentrations. Especially, hexane soluble fractions of Agrimonia pilosa, Hydrangea serrata, Machilus thunbergii, Prunella vulgaris, Saussurea lappa, Tussilago farfara, and ethyl acetate soluble fractions of Angelica gigas, Ostericum koreanum, Torilis japonica, Perilla frutescence showed moderate activity at 10 and/ or 25 (μg/ml. These fractions are promising candidates for the study of the activity-guided chromatographic purification of active compounds.

GC-ECD를 이용한 유기염소계 및 Pyrethroid계 농약 동시 분석법

김우성,이선화,김재이,정지윤,이명자,박영채,이영자,정성욱,이봉헌,박흥재 한국환경과학회 2003 한국환경과학회지 Vol.12 No.4

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organochlorine and pyrethroid pesticides using GC(ECD). An ultra-2 fused silica capillary column was used to separate and identify the products. The resolution between the last isomeric peak of cypermethrin(59.987min) and the first isomeric peak of flucythrinate(60.043min) was not satisfactory. The last isomeric peak of fenvalerate(62.344min) and the first isomeric peak of fluvalinate(62.397min) were overlapped. Recoveries of soybean sample for the most pesticides were 73.3% to 102.4%. Detection limits were between 0.004 and 0.063 ㎍/㎎ when this method was used.

Plant regeneration from callus of Iris odaesanensis Y. N. Lee native to Korea via organogenesis

Bae, Kee-Hwa,Yoo, Kyoung-Hwa,Lee, Mi-Hyun,Jeong, Jae-Hun,Choi, Yong-Eui,Yoon, Eui-Soo The Korean Society of Plant Biotechnology 2013 식물생명공학회지 Vol.40 No.3

Iris odaesanensis Y. N. Lee. is an important endangered and native plant belonging to the family Iridaceae in Korea. This study describes a method for rapid micropropagation of this species via from leaf, rhizome and root explants derived calli. Leaf, rhizome and root explants were cultured on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) for callus induction. Rhizome explants yielded calli at a frequency of 72% when cultured at 1.0 mg/l 2,4-D. Calli were maintained at 1.0 mg/l 2,4-D. These calli were transferred to MS medium supplemented with 0, 0.5, 1.0, and 2.0 mg/l 2,4-D in combination with 0, 0.5, 1.0, and 3.0 mg/l BA for adventitious shoot induction. The highest number of adventitious shoot (228.9 per petri-dish) were formed at 1.0 mg/l 2,4-D and 1.0 mg/l BA. WPM medium was the best to convert calli into plantlets, where up to 98.2% of calli were regenerated into plantlets. This in vitro propagation protocol should be useful for conservation of this endangered plant.