Patterned substrate을 이용하여 MOCVD법으로 성장된 고효율 질화물 반도체의 광특성 및 구조 분석

김선운,김제원,Kim, Sun-Woon,Kim, Je-Won 한국재료학회 2005 한국재료학회지 Vol.15 No.10

GaN-related compound semiconductors were grown on the corrugated interface substrate using a metalorganic chemical vapor deposition system to increase the optical power of white LEDs. The patterning of substrate for enhancing the extraction efficiency was processed using an inductively coupled plasma reactive ion etching system and the surface morphology of the etched sapphire wafer and that of the non-etched surface were investigated using an atomic force microscope. The structural and optical properties of GaN grown on the corrugated interface substrate were characterized by a high-resolution x-ray diffraction, transmission electron microscopy, atomic force microscope and photoluminescence. The roughness of the etched sapphire wafer was higher than that of the non-etched one. The surface of III-nitride films grown on the hemispherically patterned wafer showed the nano-sized pin-holes that were not grown partially. In this case, the leakage current of the LED chip at the reverse bias was abruptly increased. The reason is that the hemispherically patterned region doesn't have (0001) plane that is favor for GaN growth. The lateral growth of the GaN layer grown on (0001) plane located in between the patterns was enhanced by raising the growth temperature ana lowering the reactor pressure resulting in the smooth surface over the patterned region. The crystal quality of GaN on the patterned substrate was also similar with that of GaN on the conventional substrate and no defect was detected in the interface. The optical power of the LED on the patterned substrate was $14\%$ higher than that on the conventional substrate due to the increased extraction efficiency.

모바일 기기에서 눈동자 추적을 통한 원격 제어

김수선(Kim, Su-Sun),강석훈(Kang, Seok-Hoon),김선운(Kim, Seon-Woon) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.4

본 논문은 스마트폰을 이용해 눈동자 중심을 추적하여 눈동자의 움직임에 따른 명령으로 치환하고, 이 명령 을 통해 인터페이스를 제어하는 방법에 대해 제안한다. 눈을 통해 원격 제어를 하는 이 방법은 신체적 장애가 있는 사람이나 보다 편리한 입력 방법을 원하는 사용자에게 도움을 줄 수 있다. 기존의 방법 중 대표적인 방법으로 웹캠을 이용하여 사용자의 눈동자를 추적하는 방식은 사용자 위치의 거리나 각도에 제약이 존재한다. 하지만, 본 논문에서 제 안된 방법은 휴대가 편리한 스마트폰을 이용한다. 제안한 방법은 무선 네트워크를 이용하여 사용자가 위치에 제약받지 않고 눈동자 추적을 통한 원격 제어를 할 수 있다. 이러한 방법은 PC 제어뿐 만 아니라 원격 제어가 반드시 필요한 스마트 TV 제어에 효과적으로 활용될 수 있다. This paper proposes a method to track the center of pupil and perform the remote control for interface based on the substituted commands according to movements of pupil under smart phone environment. The proposed method, which is a remote control through the movement of eyes, may be helpful for the handicapped people or users who want a more convenient input method. A method based on webcam, which is representative one among the previous methods to track pupil of user, has a few limitations on distance and angle between location of user and webcam. However, this paper uses smart phone that is convenient to carry. The proposed method can perform the remote control through tracking of pupil using wireless network without any restriction on the location of users. Thus, the method is effectively applied for controlling the smart TV that should be controlled on the distance as well as the remote control for PC.

Eaton-Lambert 증후군과 항이뇨 호르몬 과다 분비 증후군을 동반한 소세포 폐암 1예

김희,김선운,김인기,이형준,김양욱,주영돈,손창학 인제대학교 1999 仁濟醫學 Vol.20 No.1

종양수반 증후군은 암의 원발 부위 또는 전이 이의의 부위에서 발생하는 다양한 증상이라 증후를 일컬으며 진단 전에도 나타날 수 있다. 이 중 Eaton-Lambert 증후군은 드물게 나타나는 신경학적 종양수반 증후군이며, 항이뇨 호르몬 과다 분비증은 종양에 의한 항이뇨 호르몬의 이소성 분비에 의해서 생기며 이 두 가지 종양수반 증후군이 소세포 폐암에서 병발할 예는 매우 드물며 국내에서는 아직 보고된 바가 없다. 이에 저자 등은 최근 소세포 폐암으로 진단된 56세 남자 환자에서 Eaton-Lambert 증후군과 항이뇨 호르몬 과다 분비증이 동반된 1예를 경험하여 문헌 고찰과 함께 보고하는 바이다. The paraneoplastic syndrome refers to the ability of some tumors producing signs and syndromes at a distance from the site of the primary tumor or its metastasis. Eaton-Lambert syndrome has a rare neurologic menifestations and Syndrome of Inappropriate Antidiuretic Hormone (SIADH) is developed by ectopic secretion of antidiuretic hormone. The small cell lung cancer which is accompanied by above two paraneoplastic phenomenon is very rare and has not been reported in Korea. We report a case of 56-year-old male who has samll cell lung cancer accompanied by Eaton-Lambert syndrome and SIADH.

급성 백혈병 관해유도요법후 발생한 다발성 비장농양 1예

이홍기,김선운,박경동,이현성,주영돈,손창학 인제대학교 2000 仁濟醫學 Vol.21 No.1

Splenic abscess is a rare illness. Its incidence has ranged from 0.14 to 0.7 % in various autopsies conducted in the US. Even in the most recently published articles, diagnosis was made only in autopsies in 37 % of the cases. While splenic abscess may arise occasionally from contiguous spread of infection or direct trauma to the spleen, usually it develops with hematogenous spread or infection. But, bacterial endocarditis is the most common cause. RUQ pain of abdomen developed in only half of series. Splenomegaly, fever and leucocytosis was also present. When splenic abscesses are being considered in a differential diagnosis, CT scan of the abdomen has been the most sensitive diagnostic tool. Streptococcal species are the most common bacterial isolates from splenic abscesses, S. aureus is the next most common. Salmonella species are seen commonly in patients with sickle cell hemoglobinopathy. Because of the high mortality related for splenic abscess, the treatment of choice is splenectomy with adjunctive antibiotics. However, percutaneous drainage has been successful alternative. We reported a 19-years old female patient who had splenic abscess after remission induction chemotherapy of acute leukemia, successfully treated with splenectomy.

관상동맥조영술상 관상동맥 내경이 동맥경화증의 발현에 미치는 영향

표지수,최정식,이형준,김희,김선운,송진호,류종철,김두일,김동수 인제대학교 1999 仁濟醫學 Vol.20 No.2

Objectives: The effect of coronary artery diameterson theoccurrence of atherosclerosis is unknown. However, several studies have shown that the larger the vessel lumen diameter after coronary interventions, the less the probability of restenosis. We supposed that larger coronary arteries have a lower prevalence of atherosclerosis. Methods and Materials: We measured the diameters of major coronary arteries in 231 patients undertaken coronary arteriography who admitted to Paik hospital from August 1996 to May 1997. Results: The mean diameters of the left main coronary, the right coronary, the left anterior descending and the left circumflex arterieswere 4.50±0.372, 3.62±0.391. 3.55±0.404, and 3.17±0.392mm respectively. On the basis of these dimen-sion of each artery, all patients were divided into 3 groups according to the diameter: gloup A (average), group S(small), group L(large). Group A means that the diameter is within 1 SD of the mean. Group S and group L mean that the diameters are>1 SD smaller and larger, respecti-vely, than the mean. We compared the frequency of lesions ≥50% dia- meter stenosis in groups S and L for each artery. In group S versus L, respectively, the frequency of ≥50% lesion was 6.7% versus 2.6% (P = 0.40 7) in the left main artery, 60% versus 33.3%(P = 0.030) in the right coronary artery, 57.1% versus 35% (P = 0.044) in the left anterior descending artery, and 47.2% versus 23.7% (P = 0.034) in the left circu- mflex artery. For the left main artery, there was a trend toward higher frequency of lesions ≥50% stenosis in group S versus group L. For the other major vessels, the fr-equency of lesions ≥50% in the proximal or midsegment was significantly higher in gr- oup S than in group L. Conclusion: We observed that smaller coronary arteries had a higher prevalence of co- ronary disease in this study. Thus, small coronary artery dia- meter may be a risk factor for atherosclerosis.