액체로켓엔진 개발을 위한 연소불안정 연구의 중요성

윤영빈 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40

Experimental and Numerical Analysis of Slurry Flow in Chemical Mechanical Polishing

윤영빈,이도형,Mirza Baig 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.4

A slurry flow field in chemical mechanical polishing (CMP) was analyzed by using particle image velocimetry (PIV) and numerical simulations. PIV experiment for analyzing the CMP hydrodynamic regime is a novel approach and the first to combine both experimental measurements and numerical simulations. The quality of CMP in semiconductor production is characterized by its output properties, such as its removal rate (RR) and nonuniformity (NU). The nonuniformity of the wafer surface is due to the irregularity of the material removal rate across the wafer's surface and both NU and RR problems result from an uneven slurry flow distribution on the wafer surface. The slurry ow field was studied on the wafer scale under various pad and carrier rpm conditions. Direct measurement of the slurry flow field was first applied to the CMP process by adequately modifying a conventional PIV system. A numerical simulation was carried out for the validation of the current analysis and for future use under various CMP conditions. The analysis showed that the flow speed was strongly in fluenced by the pad velocity and that the overall flow field was characterized mainly by the ratio between the pad rpm and the carrier rpm. A slurry flow field in chemical mechanical polishing (CMP) was analyzed by using particle image velocimetry (PIV) and numerical simulations. PIV experiment for analyzing the CMP hydrodynamic regime is a novel approach and the first to combine both experimental measurements and numerical simulations. The quality of CMP in semiconductor production is characterized by its output properties, such as its removal rate (RR) and nonuniformity (NU). The nonuniformity of the wafer surface is due to the irregularity of the material removal rate across the wafer's surface and both NU and RR problems result from an uneven slurry flow distribution on the wafer surface. The slurry ow field was studied on the wafer scale under various pad and carrier rpm conditions. Direct measurement of the slurry flow field was first applied to the CMP process by adequately modifying a conventional PIV system. A numerical simulation was carried out for the validation of the current analysis and for future use under various CMP conditions. The analysis showed that the flow speed was strongly in fluenced by the pad velocity and that the overall flow field was characterized mainly by the ratio between the pad rpm and the carrier rpm.

만성 중심장액맥락망막병증에서 국소레이저광응고술과 유리체 내 베바시주맙 주입술의 효과 비교

윤영빈,최우석,이규원,박동근 대한안과학회 2024 대한안과학회지 Vol.65 No.4

목적: 만성 중심장액맥락망막병증에서 국소레이저광응고술과 유리체 내 베바시주맙 주입술의 효과를 비교해 보고자 하였다. 대상과 방법: 만성 중심장액맥락망막병증으로 국소레이저광응고술과 유리체 내 베바시주맙 주입술을 시행한 46명 46안을 후향적으로분석하였다. 국소레이저광응고술을 시행한 레이저군이 22안이었고, 유리체 내 베바시주맙 주입술을 시행한 주사군이 24안이었다. 6개월간의 경과 관찰 기간 동안 최대교정시력 변화와 중심황반두께 변화, 완전흡수율, 재발률을 비교 분석하였다. 결과: 중심황반두께는 레이저군과 주사군 모두 6개월째까지 유의한 부종 감소를 보였으며(각각, p<0.001, p<0.001), 경과 관찰 기간동안 두 군 사이에 유의한 차이는 보이지 않았다. 평균 최대교정시력은 두 군 모두 첫 치료 후 서서히 호전되어 6개월째 유의한 시력호전을 보였고(각각, p=0.049, p=0.048), 경과 관찰 기간 동안 두 군 사이에 유의한 차이는 관찰되지 않았다. 레이저군은 22안(22/22) 모두 망막하액이 완전흡수되었으며, 주사군은 23안(23/24)에서만 완전흡수되었다. 완전흡수된 이후, 경과 관찰 기간 동안 레이저군은9안(9/22), 주사군은 13안(13/23)이 재발을 보였으나 두 군 사이에 유의한 차이는 없었다(p=0.229). 결론: 만성 중심장액맥락망막병증에서 국소레이저광응고술과 유리체 내 베바시주맙 주입술은 해부학적 호전과 시력 호전에 효과적이었으며 국소레이저광응고술이 합병증의 우려는 있으나 상대적으로 빠른 시력 회복과 낮은 재발률을 보였다. Purpose: We compared the efficacy of focal laser photocoagulation and intravitreal bevacizumab injection in the treatment of chronic central serous chorioretinopathy. Methods: We conducted a retrospective analysis involving 46 eyes of 46 patients with chronic central serous chorioretinopathy who received focal laser photocoagulation (22 eyes) or intravitreal bevacizumab injection (24 eyes). Changes in best-corrected visual acuity (BVCA), central macular thickness, and rates of complete subretinal fluid (SRF) resolution and recurrence were compared over a 6-month period. Results: Although the focal laser photocoagulation and intravitreal bevacizumab injection groups demonstrated a significant reduction in central macular thickness at 6 months (p < 0.001), no statistically significant differences were observed between these groups at the end of the follow-up period. Notably, a gradual improvement in BVCA was observed in both groups following initial treatment, with significant improvement seen at 6 months (p = 0.049 and p = 0.048 for the laser and injection groups, respectively). However, no statistically significant difference in BVCA improvement was observed between the groups. Complete SRF resolution was achieved in 22 eyes in the laser group and 23 eyes in the injection group. Although recurrence of SRF was observed in 9 and 13 eyes in the laser and injection groups, respectively, there was no statistically significant difference between the groups (p = 0.229). Conclusions: Focal laser photocoagulation and intravitreal bevacizumab injection significantly improved anatomical and visual acuity outcomes in patients with chronic central serous chorioretinopathy. Although focal laser photocoagulation was associated with more rapid visual recovery and a lower recurrence rate compared to intravitreal bevacizumab injection, further studies are needed to evaluate its potential complications.

가공조건에 따른 녹채 주스의 색도 변화

윤영빈,최언호 서울여자대학교 자연과학연구소 2003 자연과학연구논문집 Vol.15 No.-

녹채 주스의 열처리와 원심분리, 이에 갈변방지제와 다른 과채류의 첨가가 주스의 색도 안정성에 미치는 영향을 조사하였다. 녹색 채소인 셀러리와 돌미나리 착즙액을 2: 1 로 혼합하여 착즙전 (100℃, 30초) 과 착즙후 (96 ℃, 15초) 의 열처리와 원심력 (500, 1,000, 5,000, 10,000 xg) 에 따른 색의 변화를 조사한 결과 -a값(녹색도) 과 a/b 값이 열처리와 원심력이 증가함에 따라 급격히 감소하였다. 원심분리는 착즙액 자체의 녹색도를 저하시켰으나 그 후 색의 안정에 효과적이었다. 셀러리-돌미나리 착즙 혼합액에 사과, 당근, 대추-구기자를 각각 흔합한 후 5℃와 25℃에서 저장한 결과 25℃에서 당근과의 혼합에 의한 녹색의 저하가 가장 큰 것으로 나타났다. Cysteine과 glutathione의 첨가는 주스의 색도변화에 영향을 미치지 못하였다. The effects of processing conditions such as thermal treatment, centrifuge, addition of anti-browning agents, and mixing with non-green vegetable and fruit extracts on change in colors of green vegetable juices during storage were investigated. The mixture of celery and watercress extracts at the ratio of 2 : 1 was heated at 96℃ for 15 sec and centrifuged at levels of 500, 1,000, 5,000 and 10,000xg. The Hunter value of -a (greenness) decreased by thermal treatment and with an increase in g values of centrifuge. Addition of the liquid extracts from fruits and vegetables such as apple, carrot, jujube, and lycii to celery-watercress juice decreased the -a value of the juice due to the reduction of pH with storage time, resulting in an increase of Hunter value of b. The trend was more remarkable with the addition of carrot. Therefore, considering change in color due to the unstability of chlorophyll of green vegetables, it is expected to reduce decoloration during storage by the adjustment of the mixing ratio of raw materials and centrifugal force. Cysteine and glutathione did not influence on color stability of green vegetable juice.

탐색적 자료분석과 텍스트마이닝을 이용한 전차의 발전과정 분석

윤영빈,문호석 육군사관학교 화랑대연구소 2024 한국군사학논집 Vol.80 No.1

In this study, we analyzed the evolutionary process of tank technology using structured data on tank specifications from 1916 to 2023 and unstructured text data related to tank technology research from the recent three years. Additionally, we interpreted the direction of future technological advancements in tank technology. Comparing tanks used during World Wars I and II with modern tanks, it can be assessed that contemporary tanks have reached a significantly mature stage in terms of technology. This advancement is a result of the efforts of many soldiers, strategists, and scientists, and continues today with the dedication of experts in various fields. While this fact is easily found in tank-related papers and history books, quantitative indicators and visual materials that show how tank technology has evolved and the current trends are relatively scarce. Therefore, this research processed and statistically analyzed data related to tanks, summarized the characteristics of tanks over time, diagrammed the development path of tank technology based on the theory of technological trajectories, and predicted future technological trajectories. This revealed that until the 1960s, tank technology developed focusing on firepower and mobility, and afterwards, improvements were observed in armor capability, firepower, and mobility. Since the 2000s, the development of armor has been particularly prominent. Recent research in tank technology also primarily discusses armor materials, camouflage techniques, and new concepts of protection, suggesting that innovation in protection will be central to the advancement of future tank technology. Based on these results, key implications for the development of tank technology suitable for future battlefield environments were derived.

67. 축종별 분뇨 유래 온실가스 발생 잠재량 산정 연구

윤영빈,김기원,신동성,이태훈,전태빈,나창식,원승건 한국초지조사료학회 2018 한국초지조사료학회 학술대회논문집 Vol.2018 No.09

혼합과채주스의 품질특성에 미치는 열처리와 한외여과의 효과

윤영빈,최언호 서울여자대학교 자연과학연구소 2003 자연과학연구논문집 Vol.15 No.-

사과, 당근, 샐러리, 돌미나리, 대추, 구기자의 착즙액을 3 : 3 : 1 : 1/2 : 1 : 1/2 의 비율로 혼합한 과채주스를 열처리 (96 ℃에서 15초) 또는 한외여과 (MW cut off value 80,000) 하여 밀봉하고 5℃ 와 25℃ 에서 8주 동안 저장하고 저장특성을 조사하였다. pH는 무처리구와 열처리구의 경우 4.83-4.85, 한외여과구의 경우 5.85로 나타났으며 환원당, 유리당, 유기산 등은 한외여과구에서 낮은 값을 보였다. 저장기간이 증가함에 따라 무처리구의 성분 변화가 심하게 나타났다. 총균수는 저장초기 무처리구에서 5.6 x10¹로 나타났으며 저장기간이 증가함에 따라 급격히 증가되었으며 무처리구 이외의 실험구에서는 미생물이 전혀 검출되지 않았다. 저장기간에 따른 흔합과채쥬스의 품질특성은 5℃ 에서 8주 저장하는 동안 무처리구에서 변화가 가장 심하여 pH 저하, 환원당의 감소 lactic acid의 증가, L-ascorbic acid 의 감소, 효소활성에 의한 색도의 변화 등을 야기하는 결과를 초래하였으며 25℃ 저장구에서는 그 변화가 더 심한 것으로 나타났다. 열처리구와 한외여과구에서는 대체적으로 성분에 큰 변화가 없었으며 특히 한외여과구에서 더 안정한 것으로 나타나 한외여과 처리와 저온 저장에 의하여 저장수명을 더 연장시킬 수 있을 것으로 기대되었다. Mixed fruit and vegetable juices which were composed of apple, carrot, celery, watercress, jujube and lycii at the weight ratio of 3 : 3 : 1 : 1/2 : 1 : 1/2 were heated for 15sec at 96°Cor filtered through a ultramembrane filIer(MW cutoff value 30,000) and stored for 8 weeks at 5° and 25℃. The initial pH was 4.83-4.85 in the control and the heat-treated juices and 5. 85 in the ultrafiltered juices. The ultrafiltered juices showed lower contents of reducing sugars, free sugars and organic acids than those of the control and the heat-treated juices before storage. During storage the control juices showed decrease in pH, reducing sugars and L-ascorbic acid, an increase in lactic acid and the change in color by enzyme action, more severely at 25℃, while the heat-treated juices and the ultrafiltered juices did not show remarkable changes in their composition. The storage life of juices was able to be prolonged by thermal treatment and ultrafiltration, when followed by low temperature storage.

PLIF and PIV Measurements of Jet Flames with Acoustically Forced Coaxial Air Jets

윤영빈,한정재,김문기,윤상욱 한국가시화정보학회 2005 한국가시화정보학회지 Vol.3 No.2

차세대우주추진 연구센터의 소개

윤영빈 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.5

액체로켓엔진의 연소불안정 현상

윤영빈,길태옥,임지혁 한국추진공학회 2007 한국추진공학회지 Vol.11 No.1

The review of the liquid propellant rocket engine presented. The combustion instabilities which are discovered on solid and liquid propellant in 1930, have been occurred on machines using combustion process, which are gas turbine, ramjet, scramjet and rockets, and necessity of combustion instability study became claimed. However, we have not been solved this problem up to now. Therefore, we analyzed causes and mechanisms generated combustion instability and inquired into history of combustion instability control in various countries for the liquid propellant rocket engine. 액체추진제 로켓 엔진에서 발생되는 연소불안정 현상에 대해 논의하였다. 지난 1930년대에 고체 및 액체 로켓에서 발견되었던 연소불안정 현상은 연소현상을 이용하는 가스터빈, 램 및 스크램젯, 로켓 등 모든 기관에서 문제가 대두되었고, 이러한 기관들의 안정적인 운용을 위해서는 연소 불안정성에 대한 연구가 필요하게 되었다. 그러나, 엔진을 파괴하는 심각한 현상을 초래하는 이 현상을 아직까지 완전히 제어하고 있지 못하다. 따라서, 연소불안정 현상이 발생되는 원인과 메커니즘을 알아보고, 액체추진제 로켓에 대한 각국의 개발사를 알아보았다.