화천수력발전소 오일유출 차단시스템 개선

윤창기 대한전기학회 2017 대한전기학회 학술대회 논문집 Vol.2017 No.11

TiO2 나노입자를 혼합 발광층으로 사용한 장수명 양자점 발광다이오드

윤창기,김지완 대한금속·재료학회 2023 대한금속·재료학회지 Vol.61 No.1

Colloidal quantum dots (QDs) have attractive optical and electrical characteristics for variousapplications in the display industry. They have superb properties including color tunability, which is achievedby controlling the particle size and solution processes used for quantum dot light-emitting diodes (QLEDs). Here we demonstrate high efficiency QLEDs that consist of a mixed layer of TiO2 nanoparticles (NPs) andQDs. ZnO is the key material responsible for the promising results of the electroluminescence devices, whichexhibited well-matched energy levels and robustness. In this report, Li-doped TiO2 NPs were synthesizedunder ambient conditions as an alternative electron transport layer (ETL) for QLEDs. A stable mixture ofTiO2 NPs and QDs was prepared in chlorobenzene and then applied to QLEDs without a conventional ETL. QLEDs with such a simplified structure produce a maximum luminance of 123,311 cd/m2 with a currentefficiency of 40.5 cd/A. These results are comparable to those of conventional QLEDs. Additionally, thepredicted T50 at 100 cd/m2 was 1,420 h, based on the T50 at 1,600 cd/m2. These clearly indicate not only thepromising results of the TiO2 NPs as an inorganic ETL, but also the remarkable performance of the simplifieddevice with less layers. The reduction in fabrication steps using this solution-based process is alsoadvantageous for next-generation display technology.

양자점과 정공 수송 물질의 혼합층을 사용한 양자점 전계발광 소자의 특성 연구

윤창기,오성근,김지완 한국마이크로전자및패키징학회 2021 마이크로전자 및 패키징학회지 Vol.28 No.4

Various studies for QLEDs using inkjet printing has been actively conducted. Multilayers in QLEDs need an orthogonal process inevitably using different solvents and it makes the inkjet printing process more difficult and expensive. Therefore, coating two layers in a single process can reduce the fabrication step, resulting in the process time. In this study, we fabricated QLEDs of standard structure using a mixture of emission layer and hole transport layer. The mixed layer was fabricated by dissolving TFB and QDs in chlorobenzene, and the maximum luminance of the device was 45,850 cd/m2. It shows the bright future of the electroluminescence devices applied with inkjet printing process. Quantum Dot Light-Emitting Diodes (QLEDs)는 제조 공정이 용액 공정을 기반으로 하기 때문에 잉크젯 공정에 쉽게 적용할 수 있다. 하지만 QLED의 적층은 서로 다른 용매를 사용하는 직교 공정이 필요하기 때문에 잉크젯 인쇄 공정이 더 복잡하며 비용이 상승한다. 따라서 한 번의 공정으로 두 개의 층을 증착하면 제조 단계를 줄일 수 있어 공정 시간이 절감된다. 이 연구에서 우리는 QD와 정공 수송 재료의 혼합물을 사용하여 standard 구조의 QLED를 제작하였다. TFB와 QD를 클로로벤젠에 분산시켜 혼합층에 사용하였고, 소자는 45,850 cd/m2의 최고 휘도를 나타내었다. 이 연구는 잉크젯 프린팅 공정을 적용하여 전계발광 장치를 제작할 수 있는 가능성을 확인하였다.

한국인 후천면역결핍증후군 환자에서 발생한 거대세포바이러스 망막염의 시력예후

윤창기,우세준,유형곤 대한안과학회 2009 대한안과학회지 Vol.50 No.1

Purpose: To investigate the clinical characteristics and visual outcome of cytomegalovirus retinitis in Korean patients with acquired immunodeficiency syndrome (AIDS) in the highly active antiretroviral therapy (HAART) era. Methods: The medical records of 252 patients from Seoul National University Hospital who were diagnosed with AIDS between 2003 and 2006 were reviewed retrospectively. In addition, 15 patients (19 eyes) Having cytomegalovirus (CMV) retinitis with a minimum follow-up period of more than a year were included. Visual acuity, immune status, involved retinal area, and bilaterality were analyzed. Results: All patients were treated with the HAART regimen and an anticytomegaloviral agent with the exception of two patients. In all patients, immune recovery developed and retinitis was inactivated. Moderate (≤ 0.4) and severe (≤ 0.1) visual loss developed in 10 (52%) eyes and 9 (47%) eyes, respectively. Retinal detachment and involvement of posterior pole accounted for more than 80% (8 out of 10) of moderate, and 88% (8 out of 9) of severe visual loss. Patients with bilateral retinitis were more likely to develop retinal detachment and visual loss. Delayed immune recovery was associated with moderate visual loss. Conclusions: Posterior pole involvement and retinal detachment were the major cause of visual loss in CMV retinitis in AIDS patients. Bilateral involvement and delayed immune recovery were related to retinal detachment and a poor visual outcome.

표층각막절제술을 통한 윤부유피종 제거 후의 임상결과

윤창기,김정훈,김성준,유영석,Chang Ki Yoon,M,D,Jeong Hun Kim,M,D,Seong Joon Kim,M,D,Young Suk Yu,M,D 대한안과학회 2008 대한안과학회지 Vol.49 No.6

Purpose: To evaluate the results of simple keratectomy for limbal dermoids. Methods: We reviewed the ocular records of 29 consecutive patients with limbal dermoids who had undergone simple keratectomy in Seoul National University Children’s hospital from 1989 to 2006. The preoperative and postoperative visual acuity and astigmatism levels as well as the cosmetic outcomes were measured. Results: The mean age at surgery was 28 months (range, 6~70 months), and the mean follow-up period was 56 months (range, 18~168 months). The mean visual acuity at the last follow-up was 20/30. The mean preoperative and postoperative cylinder was -2.64D and -2.12D, respectively, in the affected eye (p=0.064); and -0.79D and -0.43D, respectively, in the fellow eye (p=0.149). There was a significant correlation between preoperative astigmatism and the final visual acuity in the involved eye. No opaque lesions were visible at a distance of 1 meter in 16 of the 29 eyes (55.2%), and there were no significant complications related to the surgery. Conclusions: Simple keratectomy of limbal dermoids can be a good surgical technique to get a cosmetically acceptable corneal clarity without complication. J Korean Ophthalmol Soc 49(6):897-903, 2008

전신홍반루프스 환자에서 발생한 망막병증

윤창기,유형곤,박정현 대한안과학회 2009 대한안과학회지 Vol.50 No.8

Purpose: To investigate the clinical characteristics of retinopathy associated with systemic lupus erythematosus (SLE) and its risk factors. Methods: Medical records of patients who were diagnosed with SLE were reviewed retrospectively. The presence of retinal hemorrhage, vasculitis and a cotton wool patch were regarded as lupus retinopathy, but concomitant diabetic retinopathy and hypertensive retinopathy were excluded from the study. The correlation between the development of lupus retinopathy and the presence of positive autoantibodies was also investigated. Results: Ocular morbidity was found in 173 of 260 (66%) SLE patients. Retinopathy was detected in 52 eyes of 33 patients (12%), which included 36 eyes of 21 patients (63%) with classic retinopathy and 11 eyes of 10 patients (30%) with vaso-occlusive retinopathy. The presence of classic retinopathy coincided with the flare-up of lupus activity and completely resolved without visual impairment. However, vaso-occlusive retinopathy was not related with lupus activity, and resulted in significant visual impairments of 20/200 or less in six eyes of five patients. The disease activity of lupus assessed by the maximum SLE disease activity index was higher in patients with retinopathy (p<0.05), and the prevalence of antiphospholipid antibody was higher in patients with vaso-occlusive retinopathy than in patients with classic retinopathy (66.7% vs. 37.5%, p<0.05). Conclusions: Vaso-occlusive retinopathy in SLE can result in permanent visual impairment. Patients with high SLE activity or positive anti-phospholipid antibodies have a high possibility of developing SLE retinopathy and should be referred for ophthalmologic examination. 목적: 전신홍반루프스에 동반된 망막병증의 특징과 위험인자에 대하여 알아보고자 하였다. 대상과 방법: 전신홍반루프스로 진단받고 안과검진을 받은 환자의 의무기록을 후향적으로 조사하였다. 출혈, 혈관염, 면화반을 루프스 망막병증의 기준으로 하였고 망막병증 발생에 루프스 활동성과 자가항체 유무가 관계가 있는지 알아보았다. 결과: 전신홍반루프스 환자 260명 중 173명(66%)에서 안과 증상이 있었고 망막병증은 33명(12%) 52안에서 나타났다. 전형적인 망막병 증이 21명 36안, 혈관폐쇄성망막병증이 10명 11안으로 흔하였다. 전형적인 망막병증은 루프스 활성화시기에 발생하였고 시력이 완전히 회복되는 반면에 혈관폐쇄성망막병증은 루프스 활성화와 관련이 없었고 20/200 이하의 심한 시력감소가 5명 6안에서 나타났다. 망막병증 환자에서 루프스 활성도가 높았으며(p<0.05), 혈관폐쇄성망막병증 환자에서 항인지질항체 양성인 비율이 높았다(66.7% vs 37.5%, p<0.05). 결론: 전신홍반루프스 환자에서 혈관폐쇄성망막병증이 영구적인 시력저하를 유발할 수 있으며, 루프스의 활성도가 높거나 항인지질항체가 양성인 경우 망막병증의 발생이 높으므로 정기적인 안과 검진이 필요하다.

Strategies for Mutation Discovery in Retinitis Pigmentosa: Transition to the Next Generation

윤창기,유형곤 대한의학유전학회 2013 대한의학유전학회지 Vol.10 No.1

Retinitis pigmentosa (RP) is the most common hereditary retinal disorder and is characterized by progressive retinal degeneration and decline in vision. RP comprises a heterogeneous group of disorders caused by various genetic variants. Since the first discovery of the causal mutation in the RHO gene using positional cloning, numerous mutations have been detected in more than 60 loci and 50 genes. However, causal genes have not been discovered in about 50% of cases. We attempt here to review the strategies to identify causal alleles of retinitis pigmentosa. These include conventional methods as well as state-of-the-art technologies based on next-generation sequencing.

일즈병의 치료에서 레이저광응고술과 유리체강내 베바시주맙 주입 병합 치료의 효과

윤창기(Chang Ki Yoon),이동은(Dong Eun Lee),김현웅(Hyun Woong Kim) 대한검안학회 2016 Annals of optometry and contact lens Vol.15 No.1

Purpose: To evaluate clinical outcomes of a combined therapy of laser photocoagulation and intravitreal bevacizumab for vitreous hemorrhage in Eales’ disease. Methods: In the present retrospective study, medical records of patients who were treated with laser photocoagulation for vitreous hemorrhage due to Eales’ disease. The eyes were divided into 2 groups, the combined therapy group of laser photocoagulation and intravitreal bevacizumab, and the monotherapy group of laser photocoagulation. Best corrected visual acuity, vitreous hemorrhage grade were investigated at 1, 2, 6, and 9 months. Change of nonperfusion area and neovascularizaition area in fluorescein angiography were compared. Results: Among 14 eyes, 7 eyes underwent intravitreal bevacizumab injection and 7 eyes did not. Visual acuity improved significantly at 1 and 3 months in the combined therapy group, but not in the monotherapy group. Vitreous hemorrhage decreased significantly at 1 and 3 months in the combined group, and 1 month in the monotherapy group. There was significant difference in visual acuity at 3 months and in vitreous hemorrhage at 1 and 3 months between the groups. Neovascularizaiton area was significantly regressed only in combined therapy group (p=0.027). Conclusions: Combined laser photocoagulation with intravitreal bevacizumab injection decreased vitreous hemorrhage and neovascularization in Eales’ disease at 1 and 3 months after treatment. But these effect have not maintained thereafter.

통신망 응용을 위한 주기억장치 데이타베이스 저장 시스템의 개발

윤창기(Chang-Ki Yoon),유한양(Han-Yang Yoo),김진호(Jin-Ho Kim),백영식(Young-Sik Baek) 한국정보과학회 1994 한국정보과학회 학술발표논문집 Vol.21 No.1

고속의 통신망을 관리하기 위해 통신망의 각 장치에 대한 정보를 신속하고 정확하게 처리하는 고속의 데이타베이스 기능이 필요하다. 이 논문에서는 이러한 고속의 자료를 저장하고 관리하기 위해 주기억장치 데이타베이스 저장 시스템을 개발하였다. 이 시스템에서는 모든 데이타베이스를 주기억장치에 저장하여 디스크 입출력 없이 고속으로 자료를 처리할 수 있다. 이 논문에서는 개발한 저장 시스템은 주기억장치를 효율적을 사용하면서 데이타의 저장과 회복을 쉽게 하기 위해 데이타베이스를 파티션과 세그먼트를 이용하여 저장한다. 또한 주기억 장치 특성에 적합한 효율적인 인덱스 즉, T 트리와 수정된 선형 해싱을 제공하고자 하였다. 또 C 응용 프로그램에서 이 저장 시스템을 쉽게 사용할 수 있도록 C 함수 형태의 응용 인터페이스를 제공하였다. 이 인터페이스로 인해 데이타베이스 언어의 번역과 실행에 대한 부담을 줄일 수 있는 장점이 제공된다.

다국소 망막전위도를 통한 특발성 망막전막제거술 전후의 황반 기능 평가

윤창기(Chang Ki Yoon),김태훈(Tae Hoon Kim),김현웅(Hyun Woong Kim) 대한검안학회 2016 Annals of optometry and contact lens Vol.15 No.1

Purpose: To assess macular function after vitrectomy and membrane removal in eyes with idiopathic epiretinal membrane by means of multifocal electroretinogram (mfERG). Methods: Visual acuity, macular thickness measured by optical coherence tomography, and mfERG recordings were achieved for 14 eyes of 14 patients who having idiopathic epiretinal membrane. All exams were performed before epiretinal membrane surgery and 1, 3, and 6 months after surgery. Results: Amplitude of mfERG were 139.18 ± 73.63 nV/deg2, 114.25 ± 29.16 nV/deg2 and 134.66 ± 69.64 nV/deg2 at before surgery, after 1 month and 3 months, respectively. Implicit time were 75.23 ± 31.34 nV/deg2, 66.20 ± 25.04 nV/deg2 and 74.79 ± 15.47 nV/deg2 at before surgery, after 1 month and 3 months, respectively. There were no significant changes in amplitude and implicit time measured by mfERG before and after the surgery (p>0.05). There were no significant correlations between the changes of amplitude and implicit time and visual acuity and macular thickness change. Conclusions: Changes in mfERG recordings were not concluded to be useful for predicting clinical prognosis after epiretinal membrane surgery in this study.