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Density Acquisition and Aero-optics Measurement from BOS Images for a Hot Jet
Sangyoon Lee,Sei Hwan Kim,Hyoung Jin Lee,In-Seuck Jeung 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.3
Acquiring density field of a flow is important to understand the flow structure, especially for studying aero-optics. Background-oriented schlieren (BOS) is one of a flow visualization technique which can obtain density field of the flow. Using BOS images density gradient can be acquired quantitatively and density field can be obtained when additional numerical method is applied. In this paper, density field of a hot jet is reconstructed from BOS images by assuming the jet as asymmetric flow and applying adaptive Fourier–Hankel Abel method. Reconstructed density field is evaluated by comparing with wavefront of the optical wave propagating through the hot jet. Optical path difference (OPD) is calculated from the reconstructed density field and compared with Shack–Hartmann (S–H) sensor measured OPD map. OPD obtained from the reconstructed density field and S–H sensor show similar tendency, especially when results are time averaged and turbulence characteristics are removed. Comparing RMS OPD of each time-averaged result show 8.8% error, which is within reasonable range. Thus, it seems that the density field acquisition using BOS technique is reliable for the hot jet flow.
( Sangyoon Chung ),( Ja Seol Koo ),( Kwang Seok Kim ),( Chang Bum Bae ),( Ji Kyoung Lee ),( Joo Hee Park ),( Seung Young Kim ),( Jong Jin Hyun ),( Sung Woo Jung ),( Bora Keum ),( Beom Jae Lee ),( Yoon 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background/Aims: Immunomodulators such as azathioprine (AZA) and 6-mercaptopurine (6-MP) have been used for induction and maintenance treatment of Crohn`s disease (CD) and have effect on decrease of the steroid dose in active CD. The aims of study is to evaluate the predictive factors of response to AZA/6-MP in patients with moderate to severe CD. Methods: Among total 1,499 patients registered on Crohn`s cohort in Korea, 1,382 were enrolled in this study. The medical records including baseline characteristics, location and type of CD, complications, treatment agents, and surgical treatments were reviewed retrospectively. The patients with AZA/6-MP treatments were divided into two groups according to the additional treatments such as biologic agents and/or surgical treatment. Univariate and multivariate analyses were conducted to evaluate the predictive factors of clinical response to immunomodulators. Results: Among 1,382 patients with CD, AZA/6-MP treatment was used in 926 (67.0%). Between two groups according to AZA/6-MP treatment, the treatment group was younger than the other group (mean age, 25.8 vs 32.4, p<.001). AZA/6-MP treatment was used more frequently in patients with ileocolonic CD (62.5% vs 45.4%, p=.007) and with perianal disease (29.5% vs 21.0%, p<.001). In 926 patients with AZA/6-MP treatment, 376 (40.6%) were treated with biologic agents and/or surgical treatment. Between two groups according to the result of AZA/6-MP treatment, the disease locations were significantly different (p=.007), although the disease behaviors were not different. Multivariate analysis revealed that the disease location (p=.003) and age at diagnosis (p=.029) were significantly associated with AZA/6-MP treatment failure. Conclusions: AZA/6-MP treatment is effective on induction and maintenance treatment in CD. However, early biologic treatment should be considered in young age, colonic CD, since their AZA/6-MP treatment is less effective.
인체 공동 내부 수술용 로봇을 위한 이미지기반 레지스트레이션 알고리즘
이상윤(Sangyoon Lee),신승하(Seung Ha Shin),안재범(Jae Bum An),주진만(Jin Man Joo) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
This paper presents two numerical algorithms for registration of cross-sectional medical images such as CT (Computerized Tomography) or MRI (Magnetic Resonance Imaging) by using geometrical information from helix or line fiducials. The registration algorithms are designed to be used for a surgical robot working inside cavities of human body. A cylindrical device with a combination of line and helix fiducials were also devised and is supposed to be attached to the end-effector of surgical robot. The algorithms and the fiducial pattern were tested in various computer-simulated situations, and the results indicate excellent overall registration accuracy.
Lee, Sangyoon,Park, Sungsik,Kim, Chang-Wan,Lee, Dongjin,Lee, Chongmu,Jin, Changhyun Elsevier 2016 THIN SOLID FILMS - Vol.598 No.-
<P><B>Abstract</B></P> <P>A hydrothermal-based synthesis technique was used to produce both amorphous and nano-grained NiO nanowires. The scanning electron microscopy images showed the morphologies before and after annealing treatment at 350 and 400°C for 2h. The microstructural features of the mixed amorphous and local crystalline in as-synthesized NiO and polycrystalline in annealed NiO were characterized by X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy, respectively. The corresponding elemental compositions were determined via energy-dispersive X-ray. In addition, annealing-dependent effects on the photoluminescence spectra were observed in at least two different energy band regions, e.g., at ~395, 660, and 680nm. The photoluminescence properties, including intensity and energy, of the individual NiO nanowires varied significantly with microstructural changes arising from nickel and oxygen defects from annealing the as-synthesized amorphous NiO. The microstructural and optical origin of as-synthesized amorphous and annealed nano-grained NiO nanowires is discussed on the basis of the aforementioned results.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Amorphous and nano-grained NiO nanowires were synthesized. </LI> <LI> The structures have changed from amorphous to crystalline after annealing. </LI> <LI> The different PL properties may have resulted from annealing effects. </LI> </UL> </P>