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>

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

Toluene, Xylene, Trichloroethylene 투여가 흰쥐의 시상하부와 뇌하수체의 GnRH, GnRH Receptor, Pit-1 유전자 발현에 미치는 영향

기노석,이종태,강대성,김대환,이채관,이헌,전진호,김정호,이채언 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.2

The workplace exposure of chemicals has steadily increased, therefore the concern for subsequent effect on reproductive outcome has been an important issue in occupational medicine. In previous studies, higher rates of spontaneous abortion, reduced fertility and menstrual disorder among women, and an impairement of sperm quantity and quality among men have been associated with a wide variety of chemical agents. This study was conducted to evaluate the effects of toluene, xylene and trichloroethylene(TCE) injection on the mRNA levels of GnRH, GnRH receptor and Pit-1 genes in male rats hypothalamus and pituitary and the effects on the plasma levels of FSH, LH, prolactin and testosterone. Sprague-Dawley male rats were divided into five groups of five each according to concentration of toluene, xylene and TCE. The rats were injected subcutaneously to 0, 50, 100, 200, 400 mg/kg body weight/day of toluene, xylene and TCE, respectively for 6 days. Rat brains were excised and hypothalamus and pituitary were separated. Reverse transcription-polymerase chain reaction (RT-PCR) and RNase protection assay(RPA) were used to evaluate the GnRH, GnRH receptor and Pit-1 mRNA levels. Plasma concentrations of FSH, LH, prolactin and testosterone were assayed by radioimmunoassay(RIA). The results were as follows; 1. GnRH, GnRH receptor and Pit-1 mRNA levels in toluene and xylene injected groups, and GnRH receptor mRNA levels in TCE injected group were lowered dose-dependently. Especially, GnRH receptor and Pit-1 mRNA levels in 200mg/kg of toluene injected group, and GnRH, GnRH receptor and Pit-1 mRNA levels in 400mg/kg of toluene injected group were significantly lower than control group (p<0.05). GnRH receptor and Pit-1 mRNA levels in 400mg/kg of xylene injected group, and GnRH receptor mRNA levels in 400mg/kg of TCE injected group were significantly lower than control group(p<0.05). 2. The plasma levels of prolactin and testosterone in 400mg/kg of toluene injected group, and LH in 100, 200 and 400mg/kg of xylene injected group, and testosterone in 400 mg/kg of TCE injected group were significantly lower than control group(p<0.05). In conclusion, we speculated that toluene and xylene affected reproductive system secondarily through hypothalamus-pituitary axis, and TCE affected directly through steroidogenesis. And we recommended that further study for assessment of the reproductive toxicity of mixed organic solvent exposures should be conducted.

급성 심근경색 : Gd-DTPA 조영증강 자기공명영상 Gd-DTPA Enhanced Magnetic Resonance Imaging

정경일,김제현,이창호,이영주,김한수,소동문,이영돈,박경주,왕희정,탁승제,이철주,김선용,김옥화,임태환,문창현,최병일,서정호 아주대학교 의과학연구소 1996 아주의학 Vol.1 No.1

This study was undertaken to determine the value of gadolinium dimeglumine (Gd-DTPA) enhanced MRI in the diagnosis of acute myocardial infarction. Seven cats were subjected to 2 hours of left anterior descending coronary arteryocclusion (group 1) and 8 cats to 1 hour of occlusion (group 2). Reperfusion was followed by taking Tl-weighted MR images at 5, 15, 30, 45, 60 minutes after Gd-DTPA (0.2 mmol/kg) injection. Myocardial enhancement patterns were categorized into three zones (central ischemic, peripheral ischemic, and normal) or two zones (ischemic and normal) and the presence of injured myocardium in each zone was confirmed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Signal intensity (SI) of each zone was evaluated relative to back muscle in regard to its chronological changes and difference among the zones. Group 1 displayed three zones of enhancement in 6 cats whereas 1 cat in group 1 and all in group 2 showed two zones of enhancement. Intermediate SI central zone was compatible but smaller than TTC nonstained area, and determined to be a persistently occlusive injury. High SI peripheral zone in group 1 and high SI ischemic zone in group 2 were stained and determined as reperfused injury although reversibility was not definite. The peak SI, occurring 15 minutes after Gd-DTPA injection, of 2.47±0.48 at peripheral zone was greater than that of 1.66±0.36 at central zone in group 1 and of 1.81±0.41 at ischemic zone in group 2 (p < 0.05). SI of injured myocardium increased more rapidly and decreased more gradually than that of normal myocardium. That the features of SI change with time in injured myocardium was compatible with the results of other studies using different contrast agents. Gd-DTPA enhanced MRI differentiated persistently occlusive injury as central intermediate SI, and reperfused injury as homogenous high SI, with the maximal contrast between the two at 15 minutes after contrast injection, thus indicating the value of Gd-DTPA enhanced MRI in the diagnosis of acute myocardial infarction.

Discordance in Spirometric Interpretations Based on Korean and Non-Korean Reference Equations

Nami Kim,Mi-Hee Park,Se-yeong Kim,Chunhui Suh,Sangyoon Lee,Kun-Hyung Kim,Chae-Kwan Lee,Dae-Hwan Kim,Jong-Tae Lee 대한직업환경의학회 2013 대한직업환경의학회지 Vol.25 No.-

Objectives: Korean regression models for spirometric reference values are different from those of other ethnic groups. The purpose of this study was to evaluate discordance in spirometric interpretations based on using Korean reference equations versus non-Korean reference equations. Methods: Spirometry was performed on 825 Korean male workers from April 2009 to November 2011. The spirometric patterns and disease severity were evaluated using two Korean equations (Choi’s and Lee’s) and three equations for Caucasians (NHANES III, Morris’s, and Knudson’s), and the results of Choi’s equation were compared with the non-Korean equations. The spirometric patterns were defined as normal, restrictive, and mild and moderate obstructive. Results: The mean differences in the FEV1% and FVC% between the two Korean equations were 2.0 ± 1.3% and 3.5 ± 2.2%, respectively. Morris’s equation had the greatest difference in the FEV1% from Choi’s equation: 32.9 ± 8.5%. Knudson’s equation had the greatest difference in the FVC% from Choi’s equation: 10.5 ± 6.5%. Conclusions: The two Korean equations shared similar characteristics of spirometric interpretation. The spirometric interpretations of Choi’s equation were significantly different from those of Morris’s equation and Knudson’s equation.

관순법에 의한 휜-관 열교환기의 성능 해석

이태환,유충웅 진주산업대학교 1999 論文集 Vol.38 No.-

A cross-flow finned tube heat exchanger was investigated using a tube-by-tube method. The refrigerant R22 flows inside tubes while the air passes outside the finned tube. A self-constructed refrigerant circuitry was adopted. The refrigerant enthalpy at the exit of each tube and the average condensate layer thickness are investigated as a measure of the heat transfer and the observation with the quantity of condensation phenomenon respectively. The dependence of refrigerant enthalpy and the average condensate layer thickness on the refrigerant circuitry was also observed. It was confirmed that this method could be applied to the analysis of finned tube heat exchanger with condensation.

소아 확장성 심근증의 임상적 고찰

이성환,김준식,박근수,김명성,권태찬,김천수,이상락 啓明大學校 醫科大學 1996 계명의대학술지 Vol.15 No.1

A Clinical assessment of the 25 patients with dilated cardiomyopathy who were admitted to the Department of Pediatrics, Keimyung University Dong San Hospital from January, 1982 to June, 1993 was performed. The result were as follows: 1) Among 25 patients with dilated cardiomyopathy. 8(32%) were younger than 1 year of age at the time of admission. 2) Adriamycin toxicity was the only encountered etiologic factor in 1 patient. 3) On admission, hepatomegaly and tachycardia were noted in almost all patients. 4) The Chest X-rays showed cardiomegalies in all 25 patients, pulmonary vein congestions in 15(60%) and pleural effusion in 2(8%). 5) The electrocardiography showed left ventricular hypertrophy in 72% and supraventricular tachycardia in 32%. 6) The echocardiographic examination showed left ventricular dilatations in all patients and left atrial dilatations in 20(80%). 7) Of 18 patients who had followed mean period of 2.9 years, 10 patients died within 9 months after the diagnosis.

동축이중 제한분류의 유동 특성에 관한 연구

이태환 진주산업대학교 1998 산업과학기술연구소보 Vol.- No.5

Numerical analysis on the turbulent flow characteristics of a confined coaxial jets using the k-εturbulence model was performed. FDM(finite difference method) was applied to the differential equations such as continuity equation, mementum equation, trubulent kinetic energy equation and dissipation equation. In case of velocity ratio of 1.8 and nozzle diameter ratio of 1.3, the trends of flow in mixing region were agreed will with those of the experimental results but the development of the flow was a little delayed.

음이온 교환수지에 의한 Nitrate 제거 특성(Ⅰ)

이창원,윤태경,이동환 東義大學校産業技術開發硏究所 1998 産業技術硏究誌 Vol.12 No.-

Ion exchange performance to remove nitrate in surface and underground water was studied using commercially available strong-base anion-exchange resin of Cl? type in the continuous column reactor. The performance was tested using the effluent concentration histories for continuous glass column as a function of treated volume until resins were exhausted. The breakthrough curves gave some results : ⅰ) with the large resin amount, ⅱ) the low initial ion concentration, or ⅲ) the low feed flow rate, nitrate removal characteristics for a typical macroporous type Ⅱ resin was increased. On considering the relation between the breakthrough capacity and nitrate concentration of the influent, the use of anion exchange resin will be suitable for the higher-order water-treatment process.

인터넷 광고효과에 관한 조사연구

이태로,최만규,임국환 高麗大學校 倂設 保健大學 保健科學硏究所 2003 保健科學論集 Vol.29 No.1

As internet becomes very important communication means for numerous people, a variety of advertisement are beginning to appear on the internet. People can get information about various things and do shopping via internet. This study was carried out to investigate the effect of internet advertisement on various groups. For this study, 200 people were surveyed. The results obtained were as follows: 1. Among the various advertisement types, since most people use e-mail and check e-mail very often, the advertisement through e-mail turned out the most effective advertisement means. 2. The type of advertisement using animation and moving pictures were preferred for most consumers. 3. As for the age groups, young people had the preference for the banner style and old age groups were interested in advertisements including free gift or discount events. 4. As for the favorite hours, the people in the twenties and the thirties preferred evening time(18:00 to 24:00) and people in the forties and fifties afternoon(12:00-18:00). 5. Male consumers showed preference (or the advertisement including free service programs and female consumers preferred the advertisement including discount programs or gifts.