나선형그루브-금망의 복합윅을 갖는 히이트파이프의 전열특성에 관한 연구

장영석,이영수,서정일,Chang, Young-Suk,Lee, Young-Soo,Seoh, Jeong-Il 대한설비공학회 1986 설비저널 Vol.15 No.3

The purpose of this research was to study the characteristics of heat transfer in Heat Pipe which used the composition wick of screened groove - metallic mesh by ADI method and experimental results. As the results, the more than number of metallic mesh screen layers in a heat pipe increased, the fewer the effect of heat recovery decreased. In case of 1 - layer metallic mesh screen wick, the response of the effect in heat recovery was more rapidly showed than in case of other layers and in spite of high load, the evaporation section of Heat pipe with 1 - layer metallic mesh screen wick showed the stable response and did not show excessive super heat. There was a interrelation between thermal resistance and the variable layers, between thermal resistance and the variable gaps of metallic meshes, the heat transfer characteristics of Heat pipe were depended on the thermal resistance of composition wick.

低溫用 히이트파이프의 作動流體에 관한 硏究

장영석(Chang young suk),이영수(Lee young soo),서정일(Seoh jeong il) 한국태양에너지학회 1986 한국태양에너지학회 논문집 Vol.6 No.2

14세 여아에서 발생한 다발성 소실성 흰 점 증후군

김서영(Seo Young Kim),한규진(Kyu Jin Han),진선영(Sun Young Jin),이영훈(Young Hoon Lee),장영석(Young Suk Chang) 대한안과학회 2015 대한안과학회지 Vol.56 No.8

목적: 14세의 어린 연령에서 발병한 다발성 소실성 흰 점 증후군을 경험하였기에 이를 보고하고자 한다. 증례요약: 14세 여자 환자가 내원 3일 전 발생한 좌안 시력 저하를 주소로 내원하였다. 환자는 내원 1주 전부터 미열을 동반한 상기도 감염증상이 있었고 좌안의 시력이 저하되었다고 하였다. 내원 당시 최대교정시력은 우안 20/20, 좌안 20/200이었고 상대적 구심성 동공장애가 관찰되었다. 안저 검사에서 좌안 시신경유두의 부종과 함께 다수의 흰 점이 관찰되었고 Humphrey 시야검사에서 좌안의 생리적 암점이 확대되었다. 형광안저혈관조영술에서 초기와 후기에 과형광을 보이는 흰 점 부위는 인도시아닌그린혈관조영술에서는 후기에 확대된 저형광의 반점으로 관찰되었다. 특징적인 안저 및 혈관조영 소견으로 좌안의 다발성 소실성 흰 점 증후군을 진단하였다. 2주 후 좌안의 최대교정시력은 20/70으로 호전되었고, 안저의 흰 점은 대부분 소실되었으며, Humphrey 시야검사에서 좌안의 암점은 정상 크기로 감소하였다. 3개월 후, 안저의 흰 점은 이전보다 감소하였고, 좌안의 최대교정시력은 20/30으로 호전되었다. 결론: 다발성 소실성 흰 점 증후군은 60대 노인까지 보고된 바가 있으나 대부분의 환자군은 20대 후반의 젊은 여성이다. 저자들은 전형적인 다발성 소실성 흰 점 증후군의 임상양상으로 국내에서 보고된 가장 어린 연령인 14세 여자 환자를 경험하였기에 이를 보고하고자 한다. Purpose: To report a case of multiple evanescent white-dot syndrome (MEWDS) in a 14-year-old female. Case summary: A 14-year-old female presented with decreased visual acuity. Review of systems was unremarkable except for a recent upper respiratory infection prior to her symptoms. On examination, her visual acuity was 20/20 in the right eye and 20/200 in the left eye. Relative afferent pupillary defect was observed. Examination of the left fundus revealed optic disc edema and multiple white dots in the posterior pole. Humphrey visual field test showed enlargement of the blind spot in the left eye. Fluorescein angiography revealed hyperfluorescence and late leakage of the white dots. Indocyanine green angiography showed enlarged late hypofluorescence of the white dots. MEWDS was diagnosed and the patient was followed up with serial examinations. At a follow-up examination 2 weeks later, visual acuity in the left eye improved to 20/70. The majority of white dots on fundus had disappeared and the enlarged scotoma in the left eye recovered to normal size on Humphrey visual field test. At a follow-up examination 3 months later, visual acuity in the left eye improved to 20/30 and residual white dots had further disappeared. Conclusions: Cases of MEWDS have been reported in patients as old as 67 years; however, MEWDS is a rare disease and most patients are young females. The authors describe the youngest case to date in Korea of MEWDS in 14-year-old female with typi-cal clinical course.

당뇨망막병증 환자에서 플루레신 형광안저조영술이 신기능에 미치는 영향

김정태(Jung Tae Kim),진선영(Sun Young Jin),장영석(Young Suk Chang),황원민(Won Min Hwang),이영훈(Young Hoon Lee) 대한안과학회 2016 대한안과학회지 Vol.57 No.10

목적: 당뇨망막병증 환자에서 플루레신을 이용한 형광안저조영술 시행 전후의 신기능의 변화에 대하여 알아보고자 한다. 대상과 방법: 2004년 4월부터 2014년 12월까지 당뇨망막병증을 진단 받은 비투석 환자 80명을 대상으로 플루레신 형광안저조영술 시행 전후 1주일 이내의 혈액검사를 후향적으로 분석하여, blood urea nitrogen (BUN)/serum creatinine (Scr)및 estimated glomerular filtration rate (eGFR)의 변화를 측정하고, chronic kidney disease (CKD) stage에 따라 플루레신이 신기능에 미치는 영향을 평가하였다. 결과: 형광안저조영술 시행 전후 측정한 BUN, Scr의 평균값은 변화가 없었고, 추정 사구체여과율(eGFR)은 형광안저조영술 시행 전과 비교하여 후에 감소는 없었으며, 4 mL/min per 1.73 m2의 증가를 보였다(p=0.006). CKD stage로 구분한 환자군에서는 CKD stage 5, 4, 2 & 1에서 형광안저조영술 시행 전후 신기능에 변화는 없었고, CKD stage 3에서는 형광안저조영술 시행 후에 eGFR이 증가되었다(p=0.042). 결론: 당뇨망막병증 환자에서 플루레신을 이용한 형광안저조영술 시행 전후의 신장 기능은 유의한 변화를 보이지 않았으며, 만성신부전 정도에 따른 분류에서도 시술 전후의 신기능의 감소는 관찰되지 않았다. 이에 투석을 시행하지 않는 당뇨망막병증 환자에서 플루레신을 이용한 형광안저조영술은 신기능 저하의 위험성이 크지 않은 비교적 안전한 진단법이라 할 수 있다. <대한안과학회지 2016;57(10):1598-1603> Purpose: This study was designed to compare the change of renal function before and after fluorescein angiography in patients with diabetic retinopathy. Methods: This study included 80 patients diagnosed with diabetic retinopathy who did not receive dialysis from April 2004 to December 2014. Based on retrospective analysis of a blood test performed within one week before and after fluorescein angiography, the changes of blood urea nitrogen (BUN), serum creatinine (Scr), and estimated glomerular filtration rate (eGFR) were measured. Additionally, the effect of fluorescein angiography on renal function was estimated according to chronic kidney disease (CKD) stage. Results: The average BUN/SCr before and after fluorescein angiography was not statistically significantly different before and after fluorescein angiography. The average eGFR before and after fluorescein angiography increased from 62.62 ± 31.59 to 66.46 ± 31.22 (p = 0.006). Regarding changes in renal functions according to CKD stage, based on the average eGFR in CKD stages 5, 4, 2, and 1, no significant differences were observed in renal functions before and after fluorescein angiography, whereas eGFR was significantly increased after fluorescein angiography at CKD stage 3 (p = 0.042). Conclusions: In patients with diabetic retinopathy, BUN/Scr and eGFR were not significantly different before or after fluorescein angiography. Moreover, the deterioration of renal function was not observed at any CKD stage. Therefore, fluorescein angiography is a relatively safe diagnostic examination in patients with diabetic retinopathy who did not receive dialysis due to the low-risk of renal function deterioration. J Korean Ophthalmol Soc 2016;57(10):1598-1603

당뇨황반부종 환자에서 이미지 압축이 빛간섭단층촬영 결과 해석에 미치는 영향

강선아,장영석,김종우,김철구,이태곤,김재휘,Sunah Kang,Young Suk Chang,Jong Woo Kim,Chul Gu Kim,Tae Gon Lee,Jae Hui Kim 대한안과학회 2014 대한안과학회지 Vol.55 No.9

Purpose: To evaluate the influence of image compression on optical coherence tomography (OCT) images in eyes with diabetic macular edema (DME).Methods: Twenty eyes of 30 patients diagnosed with DME were included in this retrospective observational case series. Horizontal OCT scans centered at the center of the fovea were conducted using spectral-domain OCT (Spectral OCT/SLO<SUP>Ⓡ). The images were exported to Tag Image File Format (TIFF) and then transformed to 10, 5, and 1 quality of Joint Photographic Experts Group (JPEG) format using Photoshop. OCT images were taken before and after intravitreal bevacizumab injection. The presence of intraretinal fluid, foveolar detachment, and photoreceptor inner segment/outer segment (IS/OS) disruption were evaluated in each image. Results: The mean (+/- standard deviation) size of TIFF images and 10, 5 and 1 quality JPEG images were 1712.0, 183.3 ± 6.8, 90.9 ± 4.3, 42.8 ± 1.4 kilobytes (KB), respectively, before the injection and 1712.0, 189.5 ± 9.1, 94.9 ± 5.6, 43.4 ± 1.8 KB, respectively, after the injection. The presence of intraretinal fluid, foveolar detachment, and photoreceptor IS/OS disruption identified in TIFF images was also identified in the compressed JPEG images. Conclusions: Quality of retinal OCT image did not influence the estimation of DME despite the JPEG image being compressed to approximately 1/40 of the original TIFF image size. J Korean Ophthalmol Soc 2014;55(9):1320-1326

오스템퍼링처리한 C/V 흑연주철의 마멸특성에 미치는 오스템퍼링 온도의 영향에 관한 연구

김창규,김중배,장영석 ( Chang Gyu Kim,Jung Bae Kim,Young Suk Jang ) 한국주조공학회 1996 한국주조공학회지 Vol.16 No.3

N/A C/V graphite cast iron containing a small amount of Cu and Mo for better hardenability and microstructure, was poured into the CO₂mold and then austenitized at 900℃ for 2hours. After austenitizing, the specimens of castings were austempered at 250℃, 300℃ and 350℃, respectively. The interrelationship among matrix structures, mechanical properties, wear characteristics, and austempering temperatures were investigated in this study. Wear amount increased with the increase of ferrite and retained austenite. The amount of sliding wear loss increased as sliding speed and final load increased, and wear loss of austempered C/V graphite cast iron under dry sliding condition was characterized by three models; initial wear, stationary wear and abnormal wear. The wear amount decreased with the decrease of austempering temperature, with the increase of tensile strength and hardness.

3단 히트파이프 제빙적용

장기창(Ki Chang Jang),이영수(Young Soo Lee),나호상(Ho Sang Ra),장영석(Yeong Suk Jang) 대한설비공학회 2001 대한설비공학회 학술발표대회논문집 Vol.2001 No.-

망막혈관종성증식에 동반된 망막색소상피파열에서 항혈관내피세포성장인자 주입술의 임상결과

황현지(Hyun Ji Hwang),장영석(Young Suk Chang),김종우(Jong Woo Kim),이태곤(Tae Gon Lee),김철구(Chul Gu Kim),조성원(Sung Won Cho),이동원(Dong Won Lee),한정일(Jung Il Han),김재휘(Jae Hui Kim) 대한안과학회 2016 대한안과학회지 Vol.57 No.1

Purpose: To evaluate the treatment outcomes of intravitreal anti-vascular endothelial growth factor (VEGF) therapy for retinal pigment epithelial (RPE) tear in retinal angiomatous proliferation (RAP). Methods: In the present study we retrospectively analyzed the medical records of 14 patients (14 eyes) diagnosed with RPE tear secondary to RAP treated with intravitreal anti-VEGF. Best-corrected visual acuity (BCVA) when the RPE tear developed was compared with BCVA at 6 months and at the final follow-up. Results: The mean age of the study patients was 75.1 ± 7.0 years and the mean follow-up period was 23.7 ± 13.7 months. During the follow-up period, patients were treated with a mean of 2.8 ± 1.3 intravitreal anti-VEGF injections. The mean logarithm of minimal angle of resolution BCVA when the RPE tear developed, at 6 months and at the final follow-up was 1.25 ± 0.44, 1.44 ± 0.56, and 1.65 ± 0.39, respectively. The BCVA at 6 months was not different from the baseline value (p = 0.258), whereas the BCVA at the final follow-up was significantly worse than the baseline value (p = 0.002). Conclusions: The prognosis of RPE tear in RAP is poor despite anti-VEGF therapy. This result suggests further investigations regarding the prevention of RPE tear or more effective treatment method for this condition are necessary.

스펙트럼 영역 빛간섭단층촬영을 이용한 한국인의 연령과 성별에 따른 황반부 층별 두께 연구

김청환(Chung Hwan Kim),진선영(Sun Young Jin),이영훈(Young Hoon Lee),장영석(Young Suk Chang) 대한안과학회 2016 대한안과학회지 Vol.57 No.2

목적: 황반부 두께의 측정과 분석으로 임상에서 광범위하거나 국소적인 망막질환의 진단에 도움을 주고 또한 연구에 있어서 기초자료로 사용하고자 한다. 대상과 방법: 대상자의 연령은 20세부터 69세 사이로 선정하였고 20대부터 60대까지 남녀 각각 5명씩 총 50명, 100안을 대상으로 하였다. 대상자 모두 Heidelberg Spectralis?? OCT로 Enhanced depth image를 얻었고, Heidelberg eye Software (version 1.9.10.0, Heidelberg Engineering, Heidelberg, Germany)에서 제공하는 영상분할과 황반 두께지도 기능을 이용하여 측정하였다. 결과: 중심황반두께는 망막신경섬유층에서 11.35 ± 2.11 μm, 신경절세포층에서 13.33 ± 4.16 μm, 내망상층에서 19.38 ± 3.20 μm, 내핵층에서 18.23 ± 4.66 μm, 외망상층에서 23.27± 6.83 μm, 외핵층에서 91.97 ± 9.59 μm, 망막색소상피층에서 16.68 ± 1.83 μm, 내망막층에서 179.82 ± 29.99 μm, 광수용체층에서 88.32 ± 2.81 μm였다. 근시에 따른 각 층의 두께는 유의한 차이를 보이지않았고, 황반부 모든 층에서 연령에 따른 유의한 차이를 보이지 않았으며, 중심황반의 각 층에서 여성이 남성에 비해 유의하지는 않았으나 얇은 두께를 보였다. 결론: 황반 두께의 차이는 황반 질환의 발생에도 관련이 있는 것으로 알려져 있어서 앞으로 황반 질환의 형태를 평가하는 데 있어 본 연구자료가 좋은 참고가 될 수 있을 것이다. Purpose: To analyze macular layer thickness using spectral domain optical coherence tomography (SD-OCT) in normal subjects. Methods: One hundred normal eyes were enrolled in this study. Macular thickness was measured via enhanced depth imaging using Heidelberg Spectralis?? OCT, using calipers within the program. Results: Central subfield thickness was 11.35 ± 2.11 μm in the retinal nerve fiber layer, 13.33 ± 4.16 μm in the ganglion cell layer, 19.38 ± 3.20 μm in the inner plexiform layer, 18.23 ± 4.66 μm in the inner nuclear layer, 23.27± 6.83 μm in the outer plexiform layer, 91.97 ± 9.59 μm in the outer nuclear layer, 16.68 ± 1.83 μm in the retinal pigment epithelium layer, 179.82 ± 29.99 μm in the inner retinal layer, and 88.32 ± 2.81 μm in the photoreceptors layer. No significant differences were observed in the spherical equivalent according to age. Despite no significant differences being present, the macular central subfield thickness was thinner in women than in men. Conclusions: In the present study, differences in macular layer thickness were found according to age and gender which should be considered when macular diseases are evaluated.

비외상성 비당뇨병성 유리체 출혈환자에서 유리체 절제술을 통한 원인 질환 분석

한규진(Kyu Kin Han),이영훈(Young Hoon Lee),장영석(Young Suk Chang) 대한안과학회 2015 대한안과학회지 Vol.56 No.12

목적: 당뇨 및 안외상을 제외한 자발성 유리체 출혈의 치료적 유리체 절제술 후 확인된 원인 질환과 수술 후 시력 예후에 관하여 알아보고자 하였다. 대상과 방법: 비외상성, 비당뇨병성 유리체 출혈로 2010년 3월부터 2013년 12월까지 본원에서 유리체 절제술을 시행한 환자 중 1년이상 경과관찰이 가능했던 환자를 대상으로 하였다. 환자의 과거력과 수술 전 및 수술 후 1, 3, 6, 12개월의 시력 및 안압을 확인하였다. 결과: 157명 157안을 대상으로 후향적으로 의무기록을 조사하였다. 유리체 출혈의 흔한 원인은 분지망막정맥폐쇄, 망막 열공, 나이관련황반변성이었다. 나이관련황반변성과 중심망막정맥폐쇄 환자에서는 나쁜 시력 예후를 보였다. 27안에서는 반대편 눈에 격자형 망막변성 또는 망막열공이 발견되어 장벽레이저술을 시행하였다. 결론: 정확한 진단이 어려운 자발성 유리체 출혈 환자에서 가장 흔한 원인 질환은 망막정맥폐쇄였다. 시력 예후는 원인 질환에 따라 다르지만 황반부를 침범하지 않는 경우 수술 후 시력호전을 기대해 볼 수 있다. 초음파검사상 명확한 망막박리의 소견이 보이지 않더라도 일부에서는 국소적 망막박리를 동반한 망막 열공의 가능성이 있음을 염두에 두어야겠다. Purpose: In this study we evaluated and analyzed the causes and prognosis of spontaneous vitreous hemorrhage except direct ocular trauma and diabetic retinopathy-induced vitreous hemorrhage confirmed after therapeutic vitrectomy. Methods: The present study included Non-traumatic, non-diabetic vitreous hemorrhage patients who underwent vitrectomy in our hospital from March 2010 to December 2013 and were followed up for more than 1 year. Past history, preoperative visual acuity and intraocular pressure were evaluated postoperatively at 1, 3, 6 and 12 months. Results: A total of 157 patients (157 eyes) were included in the study. Common causes of vitreous hemorrhage were branch retinal vein occlusion, retinal tear and age-related macular degeneration. Age-related macular degeneration and central retinal vein occlusion patients showed a poor visual prognosis. Lattice retinal degeneration or retinal tear in the opposite eye was observed in 27 patients and therefore, barrier laser was performed. Conclusions: The most common cause of spontaneous vitreous hemorrhage was retinal vein occlusion. Visual prognosis varied depending on the cause of disease, but significant vision improvement can be expected if the macula is not involved. Additionally, in some patients without evidence of retinal detachment on ultrasound, a possible retinal tear accompanied by localized retinal detachment should be considered.