식도 외 역류의 도그마

박일석,Park, Il-Seok 대한후두음성언어의학회 2016 대한후두음성언어의학회지 Vol.27 No.2

Laryngopharyngeal reflux (LPR) disease is an extraoesophageal variant of gastro-esophageal reflux disease that can affect the larynx and pharynx. LPR is associated with symptoms of laryngeal irritation such as throat clearing, coughing, and hoarseness. The main diagnostic methods currently used are laryngoscopy and pH monitoring. The most common laryngoscopic signs are redness and swelling of the throat. However, these findings are not specific of LPR and may be related to other causes or can even be found in healthy individuals. Furthermore, the role of pH monitoring in the diagnosis of LPR is controversial. A therapeutic trial with proton pump inhibitors (PPIs) has been suggested to be cost-effective and useful for the diagnosis of LPR. However, the recommendations of PPI therapy for patients with a suspicion of LPR are based on the results of uncontrolled studies, and high placebo response rates suggest a much more complex and multifactorial pathophysiology of LPR than simple acid reflux. Laryngoscopy and pH monitoring have failed as reliable tests for the diagnosis of LPR. Empirical therapy with PPIs is widely accepted as a diagnostic test and for the treatment of LPR. However, further research is needed to develop a definitive diagnostic test for LPR.

노인성 후두의 조직병리학적, 생리학적 특성

박일석,Park, Il-Seok 대한후두음성언어의학회 2014 대한후두음성언어의학회지 Vol.25 No.1

Age-related changes in larynx can have a direct impact on voice quality and general comfort level. Observations of vocal aging have spanned perceptual, acoustic, aerodynamic, physical, electromyographic (EMG) and histological levels. Evidence of differential vocal aging in relation to gender and physical condition has been reported. Perceptual, acoustic, aerodynamic, kinematic, EMG and histological data document age-related changes in laryngeal structure and function with advancing age. These changes contribute to a functional age-related impact of vocal hypofunction or compensatory hyperfunction. This review will focus on the current understanding of the clinical and cellular changes in the larynx that lead to presbyphonia.

수평원관상의 LiBr-H$_{2}$O 액막흡수현상 해석

박일석,최도형,Park, Il-Seok,Choe, Do-Hyeong 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.2

A numerical study for vapor absorption into LiBr-H$_{2}$O solution film flowing over horizontal circular tubes has been carried out. The momentum, energy and diffusion equations, which are parabolized by the boundary- layer approximation, are solved simultaneously for various mass-flow rates and inlet conditions. The results for the velocity, temperature and concentration fields, as well as the heat and mass flux at the free surface are presented. The effects of inlet conditions, i.e., flow rate, temperature and concentration, on the absorption process are also examined and discussed.

흡인화상환자에서 발생하는 후두 및 기관 협착

박일석,장재혁,김범규,김용복,노영수,안회영,김종현,Park Il-Seok,Chang Jai-Hyuk,Kim Beom Gyu,Kim Yong Bok,Rho Young Soo,Ahn Hwoe Young,Kim Jong Hyun 대한기관식도과학회 2005 大韓氣管食道科學會誌 Vol.11 No.1

Background and Objectives : Laryngotracheal stenosis in bum patients with inhalation have features distinct from other stenosis after intubation or tracheostomy. However few studies have been reported and the incidence was reported variable. The purpose of this study is to evaluate the clinical manifestation and the incidence of laryngotracheal stenosis in bum patients with inhalation. Methods We retrospectively analyzed 138 bum Patients diagnosed inhalation injury who admitted to Hangang Sacred Heart Hospital from July 2002 to June 2004. Result : 5 patients were developed laryngotracheal stenosis. The incidence of Laryngotracheal stenosis in bum patients with inhalation was $3\%$. Symptom developed early in 2 patients, late in 3 patients.4 patients required trachostomy as initial airway support. The location of stenosis is subglottic region except 1 patient. Montgomery T-tube was inserted in 3 patients, and Single-stage laryngotracheal reconstruction was performed in 1 patient. Conclusion Incidence of laryngotracheal stenosis in our study is lower than other reports due to late presentation of symptom and early discharge after acute bum stage. Inhalation injury may lead to severe complication and sequelae, therefore physicians should be have a awareness for early diagnosis and all burn patients who have a history of inhalation injury should be followed closely.

수직평판을 타고 흐르는 층류파동액막류에 대한 체적분율식 시간차분법에 따른 해석 결과 비교

박일석(Il Seouk Park),김영조(Young Jo Kim),민준기(June Kee Min) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.11

액막류는 레이놀즈수 및 유동 안정성에 의해 파동이 없는 층류액막류, 파동을 동반한 층류 액막류 및 난류액막류로 구분된다. 파동액막류는 강한 비선형성에 의해 매우 복잡하여 기존에는 주로 실험적 연구가 진행되었다. 수치적 해석은 주로 파동이 없는 경우에 국한되었으며 여러 가지 자유표면 해석기법을 이용하여 평균액막두께를 예측하였다. 이 연구에서는 층류액막류의 파동현상을 레이놀즈수 20~1000 범위에서 수치해석하였다. 이 때, VOF 자유표면 해석기법에 기반한 여러 가지 수치방법을 비교 연구하였으며 평균액막두께, 파동속도 및 진폭을 실험결과와 비교하였다. Liquid film flows are classified into waveless laminar, wavy laminar, and turbulent flows depending on the Reynolds number or the flow stability. Since the wavy motions of the film flows are so intricate and nonlinear, studies on them have largely been experimental. Most numerical approaches have been limited to the waveless flow regime. The various free surface?tracking schemes adopted for this problem were used to more accurately estimate the average film thickness, rather than to capture the unsteady wavy motion. In this study, the wavy motions in laminar wavy liquid film flows with Reynolds numbers of 200?1000 were simulated with various numerical schemes based on the volume of fluid (VOF) method for interface tracking. The results from each numerical scheme were compared with the experimental results in terms of the average film thickness, the wave velocity, and the wave amplitude.

내부와 외부에서 증발과 응축이 발생하는 수직관에 대한 유동 해석

박일석(Il Seouk Park) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.8

A numerical study for the flow, heat and mass transfer characteristics of the evaporating tube with the films flowing down on both the inside and outside tube walls has been carried out. The condensation occurs along the outside wall while the evaporation occurs at the free surface of the inside film. The transport equations for momentum and energy are parabolized by the boundary-layer approximation and solved by using the marching technique. The calculation domain of 2 film flow regions (evaporating and condensation films at the inside and outside tube wall respectively) and tube wall is solved simultaneously. The coupling technique for the problem with the 3 different regions and the 2 interfaces of them has been developed to calculate the temperature field. The velocity and temperature fields and the amount of the condensed and evaporated mass as well as the position where the evaporating film is completely dried out are successfully predicted for various inside pressures and inside film inlet flow rates.

위성영상에 따른 산림 탄소저장량 추정 정확도 비교ㆍ분석

박일석(Park, IlSuk),허준(Heo, Joon),정재훈(Jung, JaeHoon),유수홍(Yoo, SuHong),김경민(Kim, KyoungMin) 대한공간정보학회 2011 한국지형공간정보학회 학술대회 Vol.2011 No.5

열간압연 이후 주행하는 고온 강재의 냉각해석에서 소재의 물성변화 효과 연구

박일석(Il Seouk Park),박정은(Jung Eun Park) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.5

열연 판재 제조과정에서는 제품의 강도와 인성을 제어하기 위해 압연 직후 800℃ 이상의 고온 소재를 수냉각 방식으로 급속 냉각시킨다. 이 과정에는 소재 표면과 냉각수 사이의 비등 열전달 현상과 소재 표면에 쌓이는 체류수의 자유표면 유동, 소재의 고속 주행 등 매우 복잡한 물리현상들을 포함하고 있다. 본 연구에서는 이 모든 물리 현상들을 수치적으로 모델링한 해석 모델을 적용하여 기본 열전달 해석을 수행한다. 실제로 소재는 냉각에 의해 내부에서 오스테나이트로부터 페라이트로 상변태가 일어나고 이로 인해 소재의 국부적인 열물성치의 변화가 발생하지만 본 연구에서는 상변태를 직접 푸는 방법 대신 이미 알려진 소재의 온도에 따른 물성변화 곡선을 이용하여 냉각해석을 수행하고 이를 기존의 일정 물성치 조건에서 해석한 결과와 비교하여 소재의 물성변화가 소재 냉각에 미치는 영향과 상변태 해석의 필요성에 대해 검토하였다. In the manufacturing process of steel plates, materials at high temperatures above 800°C are rapidly cooled by using a circular impinging water jet to determine their strength and toughness. In this study, the basic heat and fluid flow is solved by using the existing numerical model for boiling heat transfer. Actually, steel undergoes a phase change from austenite to ferrite or bainite during the cooling process. The phase change induces changes in its thermal properties. Instead of directly solving the phase change and the material cooling together, we solve the heat transfer only by applying the thermal properties that vary with temperature, which is already known from other studies. The effects of the changes in the thermal properties on the cooling of steel and the necessity of calculating the phase change are discussed.

영상기반 HD Map 플랫폼을 이용한 시설물 관리 시스템 구축

박일석(Park, Ilsuk) 대한토목학회 2019 대한토목학회 학술대회 Vol.2019 No.10

다양한 대기풍속 및 대기온도 구배 조건에서의 공장 배출 가스의 확산 특성에 관한 연구

박일석(Il Seouk Park) 대한설비공학회 2010 설비공학 논문집 Vol.22 No.11

The dispersion of plume which is emitted from a chimney is governed by a lot of factors:wind, local terrain, turbulence intensity of atmosphere, and temperature, etc. In this study, we numerically investigate the plume dispersions for various altitudinal temperature gradients and wind speeds. The normal atmosphere has the temperature decrease of 0.6℃/100 m, however, actually the real atmosphere has the various altitudinal temperature profiles according to the meteorological factors. A previous study focused on this atmospheric temperature gradient which induces a large scale vertical flow motion in the atmosphere thus makes a peculiar plume dispersion characteristics. In this paper, the effects of the atmospheric temperature gradient as well as the wind speed are investigated concurrently. The results for the developing processes in the atmosphere and the affluent’s concentrations at the ambient and ground level are compared under the various altitudinal temperature gradients and wind speeds.