연료전지 고분자 막을 통한 열 및 물질 전달 특성을 반영한 공기측 BOP 핵심 요소 부품 운전 전략 설정

박규형,엄석기 한국자동차공학회 2026 한국 자동차공학회논문집 Vol.34 No.5

A physics-based, system-level framework is developed to quantify air processing system (APS) strategies that govern internal fuel cell water management and overall systematic behavior. Air-side components are developed with coupled heat and mass transfer characteristics, including a fuel cell stack that involves condensation, a counter-flow membrane humidifier, and a centrifugal compressor. The stack model is validated against published experimental data. Furthermore, these numerical models are integrated on a piping and instrumental diagram to predict thermodynamic states. Subsequently, parametric studies were conducted on cathode pressure and stoichiometry ratio to determine the membrane-averaged relative humidity (RH), the channel outlet liquid fraction, and humidifier water supply relative to the required stack water mass flow rate. The results showed that a high-pressure/low-stoichiometry strategy could sustain membrane saturation even at low inlet RH, and could reduce humidification demand by 13%. This integrated framework could provide operating maps and design guidance to optimize APS water management.

Healthcare Utilization and Treatment Patterns in Diabetic Macular Edema in Korea: a Retrospective Chart Review

박규형,김윤영,조영준,오재령,이주은,이지은,박동호,강세웅,이원기,김하경,Michael Adena,Jonathan Tan,김시동 대한의학회 2019 Journal of Korean medical science Vol.34 No.15

Background: Limited data exist on real-world treatment patterns for diabetic macular edema (DME) in Korea. In this study, we investigated DME treatment patterns from 2009 to 2014 and the impact of baseline treatment on healthcare resource utilization and visual acuity (VA) outcomes. Methods: A retrospective cohort chart review of DME patients treated at 11 hospital ophthalmology clinics between January 1, 2012 and December 31, 2013 was conducted. We collected data on demographics, healthcare resource utilization (clinic visits, treatment visits, and visits for ocular investigations), distribution of DME treatments, and VA. Results: Overall, 522 DME patients (men, 55.2%; mean age, 59 years; mean HbA1c [n = 209], 8.4%) with 842 DME eyes were evaluated. For all treatments, healthcare resource utilization was significantly higher during the first 6 months versus months 7–12, year 2, or year 3 (P ≤ 0.001), but was highest for patients whose first treatment was an anti-vascular endothelial growth factor (VEGF) treatment (visits/quarter; anti-VEGF, 1.9; corticosteroids, 1.7; laser, 1.4). Use of macular laser therapy decreased (44% to 8%), whereas use of anti-VEGF injections increased (44% to 69%) during the study period. However, VA improvement was not commensurate with healthcare resource utilization of anti-VEGF treatment (mean VA gain, 2.7 letters). Conclusion: A trend toward increasing use of intravitreal anti-VEGF injections for DME treatment was observed in Korea. However, the frequency of dosing and monitoring was lower in clinical practice versus major clinical trials, which may have led to the less-than- favorable improvements in visual outcomes.

문화속의 과학 - 새로운 매체의 예술

박규형,Park, Gyu-Hyeong 한국과학기술단체총연합회 1999 과학과 기술 Vol.32 No.10

과학과 기술, 통신의 급속한 발달은 새로운 매체의 예술을 가능하게 한다. 컴퓨터의 마우스를 움직여서 색상을 선정하고 원하는 선이나 형태를 선택하며 편집하고 조합하여 미술계에도 디지털미디어가 새로운 표현수단으로 이용되고 있다. 이렇듯 컴퓨터와 인터넷을 통한 예술은 새로운 세기의 문화의 상징으로 전세계를 네트워크로 구성하는 또다른 예술형태를 창조해 내고 있다.

인간 배아 줄기세포의 OPS와 Grid를 이용한 유리화 동결법의 효율성 비교

박규형,최성준,김희선,오선경,문신용,차광렬,정형민 韓國受精卵移植學會 2003 한국동물생명공학회지 Vol.18 No.3

Human embryonic stem (hES) cell lines have been derived from human blastocysts and are expected to have far-reaching applications in regenerative medicine. The objective of this study is to improve freezing method with less cryo-injuries and best survival rates in hES cells by comparing various vitrification conditions. For the vitrifications, ES cells are exposed to the 4 different cryoprotectants, ethylene glycol (EG), 1,2-propanediol (PROH), EG with dime-thylsulfoxide (DMSO) and EG with PROH. We compared to types of vehicles, such as open pulled straw (OPS) or electron microscopic cooper grids (EM grids). Thawed hES cells were dipped into sequentially holding media with 0.2 M sucrose for 1 min, 0.1 M sucrose for 5 min and holding media for 5 min twice and plated onto a fresh feeder layer. Survival rates of vitrified hES cells were assessed by counting of undifferentiated colonies. It shows high survival rates of hES cells frozen with EG and DMSO (60.8%), or EG and PROH(65.8%) on EM grids better than those of OPS, compared to those frozen with EG alone (2.4%) or PROH alone (0%) alone. The hES cells vitrified with EM grid showed relatively constant colony forming efficiency and survival rates, compared to those of unverified hES cells. The vitrified hES cells retained the normal morphology, alkaline phosphates activity, and the expression of SSEA-3 and 4. Through RT-PCR analysis showed Oct-4 gene expression was down-regulated and embryonic germ layer markers were up-regulated in the vitrified hES cells during spontaneous differentiation. These results show that vitrification method by using EM grid supplemented with EG and PROH in hES cells may be most efficient at present to minimize cyto-toxicity and cellular damage derived by ice crystal formation and furthermore may be employed for clinical application.

Treatment of delayed venous congestion of the nipple-areolar complex after reduction mammoplasty

박규형,명유진 대한미용성형외과학회 2021 Archives of Aesthetic Plastic Surgery Vol.27 No.1

Reduction mammoplasty is a popular operation worldwide. Early complications include bleeding, wound dehiscence, and nipple-areolar complex (NAC) ischemia. Although uncommon, NAC ischemia can lead to necrosis of the NAC. NAC congestion is usually recognized intraoperatively or within a few hours of the operation. A 21-yearold woman with severe macromastia received bilateral reduction mammoplasty using a Wise-pattern reduction with a superomedial pedicle. NAC congestion of the left breast was identified 40 hours after the operation. Delayed venous congestion of the NAC after reduction mammoplasty has not been previously reported; in this case, delayed congestion may have been caused by partial venous obstruction aggravated by the progression of tissue edema near the pedicle. Through use of the delayed suture technique, application of nitroglycerin cream, intravenous administration of prostaglandin E1, and use of a portable negative-pressure wound therapy device, the patient’s NAC was salvaged with satisfactory nipple projection and minimal scarring

반도체 회로기판에서의 마우스바이트 결함의 고장 메커니즘과 Normalized R에 의한 검출

박규형,구본흔,허석환 한국신뢰성학회 2024 신뢰성응용연구 Vol.24 No.4

Purpose: To identify the failure mechanism of mouse-bite defects and test a detection method that uses 4-wire resistance measurements at the location of the defect. Methods: The failure of circuit boards due to mouse-bite defects was analyzed based on an electronic component failure analysis procedure. The hypothesis was then verified by finite element analysis and a reproducible reliability test. The normalized R, which normalizes the circuit resistance values to detect mouse-bite defects, was calculated and the probability distribution of the circuits was shown. The probability distribution including mouse-bite defects was visualized to distinguish the fault-free circuits from those above the 3-sigma upper limit. Results: Failure mechanisms for mouse-bite defects can include increased resistance in localized areas of the circuit. This leads to Joule heating at the mouse-bite defects. Because of the mismatch in the coefficient of thermal expansion between the copper and dielectric materials, mechanical stress can be concentrated at these sites, leading to cracking. Mouse-bite defects were defined as those with a circuit width of 4 mm or less, and a circuit thickness of 7 mm or less, based on the failure analysis results. These defects were confirmed to cause open-circuit failures under use conditions. Successful detection of mouse-bite defects was confirmed based on a 3-sigma upper limit of the Normalized R metric.Conclusion: By defining the failure mechanism of the mouse-bite defects, we confirmed the possibility of detecting these sites using a 3-sigma upper limit based on the Normalized R metric measured with a 4-wire ohmmeter.

Long-term outcomes after core extirpation of fibrous dysplasia of the zygomaticomaxillary region

박규형,Se Yeon Lee,Jong-Ho Kim,Baek Kyu Kim 대한두개안면성형외과학회 2023 Archives of Craniofacial Surgery Vol.24 No.2

Background: Fibrous dysplasia (FD) is a localized bone disorder in which fibro-osseous tissue replaces the normal bone structure. Patients with craniofacial FD often present with gradual swelling, deformity, and compromised vision or hearing. We previously introduced “the core extirpation method,” a novel surgical technique that is minimally invasive like traditional bone shaving but has longer-lasting effects. This study presents the long-term outcomes of our core extirpation method. Methods: We conducted a retrospective analysis of patients who underwent core extirpation for FD of the zygomaticomaxillary region from 2012 through 2021. Computed tomography (CT) scans were performed 6 to 12 months before the operation, immediately before and after the operation, and during follow-up visits. We performed all operations using the upper gingivobuccal approach, and we extirpated the core of the lesion while preserving the cortical structures of the zygoma and the maxilla to maintain symmetrical facial contour. Results: In 12 patients with lesions in the growth phase, anteroposterior/mediolateral (AP/ML) length discrepancies and the volume increased between preoperative and immediate postoperative CT scans. All patients’ immediate postoperative AP/ML discrepancies were stable up to 12–17 months postoperatively. Postoperative volume showed continuous lesion growth; the median volume growth rate was 0.61 cc per month. Conclusion: In this article, we present our experiences managing FD using the minimally invasive core extirpation technique, which entails small expected blood loss and can be performed as day surgery. It provides similar cosmetic outcomes as traditional bone shaving but with longer-lasting results. Although there are some limitations with the study’s retrospective nature and small sample size, our 4-year follow- up results show promising results of the core extirpation method in well-indicated patients.

국내의 나이관련황반변성에 대한 기초역학조사

박규형,송수정,이원기,윤희성,고형준,김철구,김윤영,강세웅,김하경,이병로,남동흔,이필영,김형수,김형찬,김시열,정인영,김광수,허걸,오재령,김신동,이상준,김영덕,김순현,이태곤,조성원,이동초,장무환,김시동,조영욱,배선량,이주은,엄부섭,윤일한,권순일,강재훈,김종인,문상웅,유형곤,윤영희,장광열,이성철,이성진,박태관,온영훈,권오웅,장우혁,양연식,이석준,이수영외 대한안과학회 2010 대한안과학회지 Vol.51 No.4

Purpose: To evaluate the incidence and clinical features of age-related macular degeneration (AMD) in Korea Methods: Web-based (www.armd-nova.or.kr) registration was conducted for AMD patients aged 50 or more who were newly diagnosed by retinal specialists in Korea from August 20, 2005 to August 20, 2006. Patient data including ophthalmologic examination, fundus photography, fluorescein angiogram and/or indocyanin green angiogram (ICG), past medical history, behavioral habit, combined systemic diseases were up-loaded. Results: Among finally enrolled 1,141 newly diagnosed AMD patients, 690 patients (60.5%) were male and 451 patients (39.5%) were female. The average age of AMD patients was 69.7±8.0. Early AMD was observed in 190 patients and 951 patients had late AMD. Classic choroidal neovascular membrane (CNVM) was observed in 18.6% of exudative AMD patients and 63.4 % had occult CNVM. Subfoveal CNVM was observed in 80.4% of the patients with CNVM. Among the 580 exudative AMD eyes that performed indocyanin green angiography (ICG), 184 eyes (31.7%) had polypoidal choroidal vasculopathy (PCV) and 36 eyes (6.2%) showed retinal angiomatous proliferation (RAP). Age, male gender, smoking, diabetes and hypertension significantly increased the risk of the AMD among Koreans. Conclusions: Because of the low rate of participation by retinal specialists, definite incidence of AMD was not obtainable. However, the estimated 1-year AMD incidence in the Pusan area of Korea is at least 0.4%. In contrast to Western people, 31.7% of exudative AMD cases were revealed to be PCV and 6.2% were revealed to be RAP. This discrepancy between ethnic groups should be considered in the diagnosis and treatment modality selection of Korean AMD patients. J Korean Ophthalmol Soc 2010;51(4):516-523

Optic Nerve Head Drusen Mimicking Optic Nerve Tumor

박규형,우세준,황정민 대한안과학회 2015 Korean Journal of Ophthalmology Vol.29 No.3

한 가족에서 발생한 잠복 황반이상증 2예

김주훈, 박규형Joo Hoon Kim M.D. Kyu Hyung Park M.D. 대한안과학회 2008 대한안과학회지 Vol.49 No.5

Purpose: We report two familial cases of occult macular dystrophy (OMD) presenting with a progressive decrease in central vision. Case summary: Both patients exhibited a normal ophthalmologic examination including slit lamp biomicroscope, fundus examination, fluorescein angiography, and full-field electroretinogram. However, there were central visual field defects on a Humphrey static visual field test (C 24-2) and abnormal multifocal electroretinogram (mfERG) findings affecting the central portion of the test field. Foveal thinning was also observed by optical coherence tomography images in 1 case. These findings are consistent with the clinical characteristics of occult macular dystrophy, and close observation was recommended. Conclusions: OMD is a disease characterized by a reduction in central visual acuity without visible fundus abnormalities and full field ERG. It may be misdiagnosed as optic nerve disease, a central nervous system problem, non-organic visual disorder or malingering; therefore, mfERG is essential for the diagnosis of this rare type of macular dystrophy.