http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이혜은,최성욱,Lee, Hea Eun,Choi, Sung Uk 대한토목학회 2009 대한토목학회논문집 B Vol.29 No.3B
본 연구에서는 2-방정식 난류모형인 ${\kappa}-{\varepsilon}$ 모형을 이용하여 2차원적으로 발달하는 하층 밀도류를 모의하기 위한 수치모형을 제시하였다. 타원형 편미분 방정식으로 흐름에 대한 지배방정식을 구성하였으며, 수치기법으로는 유한체적법을 사용하였다. 연구를 통해 개발된 수치모형을 기존의 실험결과와 비교하여 적용성을 검토하였다. 불연속 유입조건 밀도류의 시간별 진행에서 흐름의 불안정에 의한 와(渦)의 발생을 확인하였으며, 진행중인 불연속 유입 밀도류의 진행단계 변화와 선단부 속도의 관계를 살펴보았다. 또한, 무거운 유체 위로 이동하던 주변수체가 벽면을 접하면서 발생된 단파가 밀도류의 진행에 미치는 영향을 수직구조를 통해 살펴보았다. 한편, 개발된 모형을 이용한 수치모의에서 선단부의 진행 속도가 실험보다 느리게 모의되었다. 이는 3차원 현상인 난류의 불안정성을 모의하는 2차원 모형의 한계인 것으로 판단된다. This study presents a numerical model to simulate density currents developing two dimensionally. The ${\kappa}-{\varepsilon}$ model is used for the turbulence closure. Elliptic flow equations are solved by the finite volume method. In order to investigate the applicability of the numerical model, discontinuous density currents are simulated numerically. The vortices due to the instability at the interface are simulated, showing a good agreement with the experimental visualizations in the literature. It is also investigated that the transition from slumping phase to inertial phase occurs when a bore generated at the end wall overtakes the front. However, the propagation of the density current is retarded compared with the experimental results. Two-dimensional modeling seems to have an effect on underestimating the front velocity of the density current.
이혜은(Hea Eun Lee),이창훈(Changhoon Lee) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
Particle motion in turbulence is of major interest in many engineering fields such as coastal and environmental researches. Whereas most boundary conditions for particle motion in turbulence are rough in practice, studies on particle motion still focus on the particle motion over a flat boundary. Since the turbulence generated by rough boundaries is different from that in flat boundaries, detailed study about particle motion along rough boundary is needed. In this study, turbulence over wavy wall is investigated by spectral method. Virtual boundary method proposed by Goldstein et al. (1995) is used to impose no-slip condition at wavy virtual boundary. Also, behavior of particles in turbulence over wavy boundary is investigated by particle tracking. Simulation results are compared with the characteristics of turbulent flow over a wavy wall described in papers for evaluation. Focusing on the effect of wavy boundary on turbulent structures, simulation results from wavy boundaries with different amplitude and wavelength are compared. Streamwise vortices and low-speed streaks, which associate with particle clustering, mainly develop from the upslope region with lengthscale of wavelength in wavy wall cases. Statistics of particle concentration and motion are investigated for inertial particles released in each flow case. In common, particle concentration is high in upslope region and particle velocity and its fluctuation show different characteristics in each flow case and particle inertia.
이혜은(Hea Eun Lee),정병훈(Byoung Hun Joung),노주영(Ju Young No),주인숙(In Sook Joo),심재식(Jae Sik Shim),서경용(Kyung Young Seo) 대한산부인과학회 2002 Obstetrics & Gynecology Science Vol.45 No.6
The spontaneous rupture of splenic artery aneurysm during pregnancy is a rare but catastrophic event. Two thirds of all ruptures happen during the third trimester. Clinical presentation is often non-specific, with good hemodynamic compensation, followed by a rapid deterioration. Active management and operation are the most important procedures for diagnosis and therapy of the bleeding. Abdominal delivery will help to establish diagnosis and should be performed immediately. We report a case of a patient at 38 weeks of gestation suffering epigastric pain and fetal distress. At emergency cesarean delivery, an aneurysmal rupture of the splenic artery was found to be the reason for the hemoperitoneum. Spleen, aneurysm and the tail of the pancreas were removed. In spite of fatal hemorrhage, the patient survived but her fetus was dead. With a review of the literature on this topic, diagnostic aspects and treatment options are discussed.
Aspirin 결정화 과정 중 특성변화의 NIR 인라인 모니터링 연구
이혜은 ( Hea Eun Lee ),왕인천 ( In Chun Wang ),이민정 ( Min Jeong Lee ),서다영 ( Da Young Seo ),신상문 ( Sang Mun Shin ),최용선 ( Yong Sun Choi ),최광진 ( Guang Jin Choi ) 한국화학공학회 2010 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.48 No.6
Since the quality and performance of medicinal products are heavily dependent upon the size, shape and polymorphism of active pharmaceutical ingredients (APIs), their crystallization has been regarded as one of the most important pharmaceutical processes. In this study, NIR-based inline measurements were employed to monitor key attributes of API particles real-time during the crystallization process. Principal component analysis (PCA) method was selected to correlate inline NIR spectra while the well-known aspirin was studied as a model drug. According to our characterization results, the ratio of ethanol to acetone did not cause any change in polymorphism, but resulted in a significant difference in the nucleation time, crystal growth and crystal shape. These phenomenological changes were well correlated with the PCA`s implications. It turned out that the NIR-based inline monitoring technology can be employed well in observing and predicting key quality attributes such as crystal size during pharmaceutical crystallization processes.
광섬유-탐침과 근적외선(NIR) 분광기를 이용한 약제분말 유동층 혼합공정의 인라인 모니터링 연구
박초롱 ( Cho Rong Park ),김아영 ( Ah Young Kim ),이민정 ( Min Jeong Lee ),이혜은 ( Hea Eun Lee ),서다영 ( Da Young Seo ),신상문 ( Sang Mun Shin ),최용선 ( Yong Sun Choi ),권병수 ( Byung Soo Kwon ),방규호 ( Kyu Ho Bang ),강호경 ( H 한국약제학회 2009 Journal of Pharmaceutical Investigation Vol.39 No.1