만성 B 형 바이러스성 간질환에서 혈청 히알루론산치와 4형 콜라겐치의 임상적 의의

유영일(Young Il Yu),이재승(Jae Seung Lee),김형욱(Hyong Wook Kim),송철수(Chul Soo Song),송근암(Geun Am Song),김순호(Sun Ho Kim),이창훈(Chang Hun Lee),조몽(Mong Cho),양웅석(Ung Suk Yang) 대한내과학회 1998 대한내과학회지 Vol.55 No.3

N/A Objective: Histopathologic evaluation has been used to evaluate the degree of hepatic fibrosis. This method may have limitations because percutaneous liver biopsy is invasive and histopathologic change shows heterogenicity in the liver. It has been reported that the biochemical markers may have an important role in evaluating the degree of hepatic fibrosis. This study was performed to evaluate the clinical significances of serum hyaluronic acid(HA) and type IV collagen(IV-C) levels on hepatic fibrosis in the patients with chronic viral hepatitis B and liver cirrhosis. Methods: This study included fifty eight patients with chronic viral liver diseases caused by HBV. Scheuer`s classification was used to determine the degree of hepatic fibrosis. The levels of hyaluronic acid and type IV collagen was evaluated by one-step sandwich binding protein assay and one-step sandwich enzyme immunoassay respectively. Results: The level of hyaluronic acid and type IV collagen in stage III(HA:589.4±193.7ng/ml, IV-C:444.5±221.3ng/ml) and IV(727.5±306.1ng/ml, IV-C:5192±210.5ng/ml) were higher than stage I(HA:207.2±206.8ng/ml, IV-C:210.0±92.0ng/ml) and II(HA:223.7±172.9ng/ml, IV- C:209.6±70.7ng/ml) in the patients with chronic viral hepatitis and cirrhosis. At cutoff value of 500ng/ml for HA and 250ng/ml for IV-C in chronic hepatitis B patients, the sensitivities were 85% and 85%, and specificities were 89.5% and 78.9%, and diagnostic efficiencies were 87.9% and 81% respectively for discriminating patients with advanced hepatic fibrosis(stageIII-IV) from those with mild hepatic fibrosis(stageI-II). Conclusion: The serum levels of hyaluronic acid and type IV collagen correlated significantly with the degree of hepatic fibrosis in the patients with chronic viral hepatitis B and cirrhosis. The serum hyaluronic acid and type IV collagen is useful biochemical markers for evaluating hepatic fibrosis and follow up of the patients with chronic viral hepatitis H and cirrhosis.

네트워크 모델을 이용하여 패킷의 손실 유형을 구분하는 무선 TCP 알고리즘

유영일(Young-Il Yu),이채우(Chae-Woo Lee) 한국통신학회 2004 한국통신학회 학술대회 및 강연회 Vol.2004 No.4

시간에 따른 강도변화를 고려한 암반사면의 풍화민감특성 분석

박준영(Joon-Young Park),이정상(Jeong-Sang Lee),배성호(Seong Ho Bae),유영일(Yeong-Il Yu),오정배(Joung-Bae Oh),이두화(Du-Hwa Lee) 한국암반공학회 2006 터널과지하공간 Vol.16 No.2

암반(암석)은 생성시와는 다른 온도 압력조건, 대기와 지하수 및 강우 등의 영향으로 풍화작용을 겪게 된다. 풍화작용은 암석을 구성하는 조암광물의 화학적 성질을 변화시키며, 불연속면을 따른 물리, 화학적 제반 특성에 영향을 준다. 암석이 풍화작용을 겪게 되면 임석(암반)의 물성이 저하되는 현상이 나타나 이로 인한 사면의 파괴, 지하수의 유출, 암종간의 차별풍화로 인한 문제가 발생하기도 한다. 따라서, 대규모 사면 절개시에는 현재의 풍화특성을 분석하여 풍화상태기 앞으로 어떻게 진행될 것인지 예측하고 이 결과를 토대로 비탈면 보호 및 보강공법에 기준을 판단하는 것이 요구된다. 이러한 요구에 부응하기 위해 기존의 여러 건설사업의 설계단계에서 화학적 풍화속도와 암석의 다른 특성들을 종합하여 분석하는 화학적 풍화민감도 분석 기법이 적용되어 왔다. 그러나 기존의 화학적 풍화민감도 분석은 본래 암반이 아닌 토양의 풍화에 대해 개발된 기법이며 고려되어야 힐 변수들의 수가 많고 그 관계가 복잡하며, 공학적 시간단계별로 암반사면의 풍화민감특성을 적용하는데 한계가 있다. 또한, 기존의 방법은 주로 등방성이 강한 화강암질 암석에 특성분석 기법을 적용하여 퇴적암과 같이 이방성이 강한 암반에 적용하기 어려운 문제도 있다. 풍화지형을 연구하는 지형학자들의 연구(Oguchi et al., 1994; Sunamura, 1996; Norwick and Dexter, 2002)에서 시간에 따라 진행되는 풍화에 의한 암석의 강도저하는 음지수 함수의 형태를 나타내는 것을 제안되었다. 이 관계를 공학적으로 적용하면, 풍화 작용하는 여러 요인들의 결괴를 강도저하로 표현할 수 있으며, 강도라는 암석의 물성을 설명함으로써 공학적으로 의미가 있는 결과를 도출할 수 있다. 따라서, 이 연구에서는 전술한 관계에 의해 풍화진행 시간에 따른 암석의 강도특성 변화를 고려하여 퇴적암에 특화시킨 풍화민감특성 분석을 암반사면의 풍화민감특성을 설명하고 설계에 직접적으로 적용할 수 있는 방법으로 제안한다. Rocks undergo weathering processes influenced by changing in pressure-temperature condition, atmosphere, underground water, and rainfall. The weathering processes change physical and chemical characteristics of the rocks. Once the rocks are weathered, the characteristics of them are changed and, because of the changing, several disadvantages such as rock slope failures and underground water spouts are can occur. Before we cut a large rock slope, therefore, we must analyze current weathering conditions of rocks and predict weathering processes in the future. Through the results of such analyses, we can judge reinforcement works. In order to comply with such requests, chemical weathering sensitivity analysis which was analyzed from chemical weathering velocities and other characteristics of rocks has been applied in several prior construction works in Korea. But, It is defective to use directly in engineering fields because it was developed for soils(not rocks), it has too many factors must be considered and the relationships between the factors are not clear, and it is hard to explain the weathering processes in engineering time range. Besides above, because it has been used for isotropic rocks, this method is hard to apply to anisotropic rocks such as sedimentary rocks. According to studies from morphologists (e.g. Oguchi et aI., 1994; Sunamura, 1996; Norwick and Dexter, 2002), time dependent strength reduction influenced by weathering shows a negative exponential function form, Appling this relation, one can synthesize the factors which influence the weathering processes to the strength reduction, and get meaningful estimates in engineering viewpoint. We suggest this weathering sensitivity characterization method as a technique that can explain time dependent weathering sensitivity characteristics through strength changes and can directly applied the rock slope design.

색온도 가변 LED 조명 최적화 설계 및 제작

강다일,김근율,유영문,최희락,Kang, Da-Il,Kim, Kun-Yul,Yu, Young-Moon,Choi, Hee-Lack 한국광학회 2014 한국광학회지 Vol.25 No.2

본 논문에서는 현재 양산되고 있는 Red(621 nm), Green(530 nm), Blue(453 nm), Amber(590 nm) 등 4파장의 LED 조합을 이용하여 색온도가 가변되는 동안에도 평균연색지수 및 특별연색지수 R9 값이 높게 유지될 수 있도록 조명의 스펙트럼을 최적화하였다. 최적화 시 설계의 정확도를 높이기 위하여 실제 측정한 LED 스펙트럼을 사용하였고 광선과 기구물 사이의 상호 작용을 고려한 광선 추적 기법을 활용하여 수행하였다 또한 최적화 결과를 검증하기 위하여 색온도 가변 조명 장치를 직접 제작하였으며 광 특성을 평가한 결과 색온도가 3000 K에서 6000 K까지 변하는 동안 CRI 및 R9 값이 각각 87~90, 34~93을 나타내었다. In this paper the spectra of correlated color temperature (CCT) tunable white light-emitting diode (LED) luminaires, consisting of commercial red, green, blue, and amber LED chips, were optimized to increase color rendering index (CRI), and a special CRI of R9 for deep red color was obtained. To improve the design's accuracy, measured LED spectra were used instead of mathematically modeled ones. Real CCT tunable LED luminaires with CRIs of 87-90 and R9s of 34-93 were fabricated and demonstrated at CCTs of 3000-6000 K.

LED터널등 모듈의 폐열활용을 위한 열전소자의 발전 성능 분석

정지영(Ji-Young Jeong),허인성(In-Sung Her),이세일(Se-Il Lee),김명호(Myeong-Ho Kim),유영문(Young Moon Yu) 한국조명·전기설비학회 2015 조명·전기설비학회논문지 Vol.29 No.8

In this paper, we propose the LED(Light-Emitting-Diode) emergency lighting in a tunnel by using the thermoelectric devices. To achieve high generated power, thermoelectric device should be have high Seebeck coefficient and small contact area. Also, we reveal that a moderate heatsink required for high generated power. From the waste heat of LED tunnel lighting module (25W), the generated power was 0.062W by thermoelectric device, and it could illuminate for 1hour after charge the battery of emergency lighting during about 101hours.

다이캐스팅용 알루미늄의 성분 변화에 따른 LED 방열 특성 연구

여정규,허인성,유영문,이세일,최희락,Yeo, Jung-Kyu,Her, In-Sung,Yu, Young-Moon,Lee, Se-Il,Choi, Hee-Lack 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.8

Because of the development of LED technology, products due to high output and compact, the material with high thermal conductivity has been developed. Now that heat radiating part of the LED lamp is currently used for die casting of aluminum. The development of aluminum with excellent thermal conductivity is required. In this study, we measured the thermal properties and compared them while we produced the alloy by changing the component of die casting aluminum. From this study, the thermal conductivity and thermal resistance of the developed alloy were superior to die casting aluminum.

고출력 5 Watt LED기반 탐조등의 방열설계

이아람,허인성,이세일,유영문,김종수,Lee, A Ram,Her, In Sung,Lee, Se-Il,Yu, Young Moon,Kim, Jong Su 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.9

The heat dissipation conditions of high-power 5 watt LEDs-based searchlight modules were optimized with varying LED bar'shape, materials, and ambient temperature. The LED junction temperature was estimated by using Computational Fluid Dynamics simulation. The optimal heat dissipation conditions were found as follows; LED bar' shape: L=80 mm, W=4 mm, t=10 mm, copper material, LED junction temperature of $116.6^{\circ}C$, ambient temperature of $50^{\circ}C$, total mass of 184 g, and shadowing area of $320mm^2$. The difference between the junction temperatures of our fabricated and simulated LEDs-based searchlight modules is about $3^{\circ}C$, which confirms the validity of our thermal simulation results.

CFD 해석을 이용한 한국도로공사 표준 25 [W] LED 모듈의 방열 특성 분석

이세일,허인성,이아람,정민주,유영문,Lee, Se-Il,Her, In-Sung,Lee, A-Ram,Jung, Min-Joo,Yu, Young-Moon 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.8

Korea Expressway Corporation established standard of LED lighting fixture in Dec. 2013. To raise compatibility, the standard requires a fixed form and it is applied to street lights and tunnel lights, etc. Because streetlight has different circumstance condition from tunnel light that is down light and exposed to constant wind velocity over height of 8 meters, in case of LED module which has the same shape, characteristic of radiant heat can be different. In this paper, we designed 25 [W] LED Module that is designated by standard of Korea Expressway Corporation and analyzed characteristics of radiant heat about natural convection and forced convection. It is dropped 10.12[$^{\circ}C$] that max temperature is decreased by increasing 20 mm of bended height of heatsink at the condition of natural convection. Radiant heat characteristic of bended height 35 mm became 78.08[$^{\circ}C$] at the condition of natural convection, 55.30[$^{\circ}C$] at the condition of forced convection so that 22.78[$^{\circ}C$] is decreased that is 29.1[%] decrease. Bended height 55mm became 67.96[$^{\circ}C$] at the condition of natural convection, 48.04[$^{\circ}C$] at the condition of forced convection so that 19.92[$^{\circ}C$] is decreased that is 29.3% decrease.

아칼라지아 환자에서 성공적인 풍선확장술의 기대인자 - 연동운동이 희복된 환자를 중심으로 -

송철수(Chul Soo Song),유영일(Young Il Yu),박승근(Seung Keun Park),강대환(Dae Hwan Kang),송근암(Geun Am Song),조몽(Mong Cho),양웅석(Ung Suk Yang) 대한내과학회 1998 대한내과학회지 Vol.54 No.5

N/A Objectives: Achalasia is primary esophageal motility disorder characterized by aperistalsis in body and incomplete lower esophageal sphincter (LES) relaxation. The aim of this study was to evaluate the parameters of successful balloon dilatation predicting long term outcome Methods: 17 patients with primary esophageal achalasia from March 1995 to December 1996 were included in this study. 5 patients were performed re-balloon dilatation due to recurrenee of symptoms, We used Rigiflex Achalasia Balloon with diameter of 30 and 35mm and balloon is dilated for 1 minute at a 5 minute interval. Esophageal manometry and scintigraphy before and after 1 month of balloon dilation were compared between groups with good long term results and relapsed Results: 1) After balloon dilatation, LES pressure, basal esophageal pressure and retention rate were significantly decreased 2) After 6 months of dilatation, 12 patients were successfully treated and 5 patients were recurred 3) No significant pre-dilatation parameters were found to predict the recurrence 4) After 1 month of dilatation, patients with recurrence of symptoms showed significant higher LES pressure and retention rate 5) 2 patients showed recovery of the peristasis, and in these patients, amplitude of esophageal body contraction of pre- and post-balloon dilatation were significantly high Conclusion: After 1 month of dilatation, LES pressure and retention rate can predict the outcome after balloon dilatation and high amplitude of esophageal body contraction predict recovery of peristalsis and long term good result

레이저 유도 화재 대피 시스템

장창섭(Chang-Sub Jang),유영일(Young-il Yu),홍성일(Sung-IL Hong),이규진(Gyu-Jin Lee) 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6