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Concept Verification of Three-Layer DOI Detectors for Small Animal PET
Hong, Seong Jong,Kwon, Sun Il,Ito, Mikiko,Lee, Geon Song,Sim, Kwang-Souk,Park, Kwang Suk,Rhee, June Tak,Lee, Jae Sung IEEE 2008 IEEE transactions on nuclear science Vol.55 No.3
<P> Improved spatial resolution without sacrificing sensitivity is one of the most challenging developmental goals for small animal PET scanners. The 3-layer configuration that we propose here utilizes relative offsets of half a crystal pitch in x- and y-directions, and pulse shape discrimination to obtain depth of interaction (DOI). Three layers of crystals with a dimension 1.5<TEX>$\,\times\,$</TEX>1.5<TEX>$\,\times\,$</TEX>7.0mm <TEX>$^{3}$</TEX> were composed of a L <TEX>$_{0.2}$</TEX> GSO (Lu<TEX>$_{0.4}$</TEX> Gd<TEX>$_{1.6}$</TEX> SiO<TEX>$_{4}$</TEX>: Ce) crystal layer and a L<TEX>$_{0.9}$</TEX> GSO (Lu<TEX>$_{1.8}$</TEX> Gd <TEX>$_{0.2}$</TEX> SiO<TEX>$_{4}$</TEX> : Ce) crystal layer aligned with each other, and a L <TEX>$_{0.9}$</TEX> GSO crystal layer offset at half a crystal pitch in x- and y-directions. The L<TEX>$_{0.9}$</TEX> GSO crystal layer was attached to a Hamamatsu H9500 flat-panel PMT. The devised small animal PET scanner has a diameter of 84 mm with one detector ring, and can be upgraded to two detector rings. GEANT4 Monte-Carlo simulation was used to estimate sensitivities of <TEX>$\sim 12\hbox{\%}$</TEX> and <TEX>$\sim 20\hbox{\%}$</TEX>, respectively, at the center of one and two PMT ring system with an energy window of 350 <TEX>$\sim$</TEX> 750 keV. We present flood images with peak-to-valley ratios of about 5–6 obtained using <TEX>$^{22}$</TEX> Na and layer identification capability of <TEX>$\sim 99\hbox{\%}$</TEX> with pulse shape analysis, and verified the basic concepts of multi-layer small animal PET. </P>
User Analysis and Design of the Pelvic Airbag Cushion System for Absorbing Falling Impact Energy
( Kwang Tae Jung ),( Sung Min Kim ),( Hwan Kim ),( Keyoung Jin Chun ),( Jae Soo Hong ) 한국감성과학회 2014 춘계학술대회 Vol.2014 No.-
The aim of this study is to design a pelvic airbag cushion system for absorbing falling impact energy. The American National Safety Council announced that 50.7% of accidental household fatalities were old people. In Korea, persons above sixty years old encountered more accidents than persons below sixty, too. From the analysis of old people`s accidents in Korea, 55.3 percent of accidents were falls and slips, 7.5 percent were conflicts, and 4.5 percent were getting cut or being torn by an object. The result shows the importance of old people`s injury prevention from falls or slips. Old people`s characteristics for falling were identified to develop a product to prevent old people`s injury from falling. Design directions considering old people`s characteristics for falling were proposed for the design. Finally, design of the pelvic airbag cushion system for absorbing falling impact energy was developed
Characteristics of Supersonic Nozzle and Jet Impingement
Hong, Seung-Kyu,Lee, Kwang-Seop,Sung, Woong-Je The Korea Institute of Military Science and Techno 2001 한국군사과학기술학회지 Vol.4 No.2
Viscous solutions of supersonic side jet nozzle and supersonic jet impinging on a flat plate are simulated using three-dimensional Navier-Stokes solver. For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful devise as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. The aerodynamic characteristics of the side jet devise itself are examined in terms of key parameters such as the side jet nozzle geometry, the chamber pressure and temperature. On the other hand, the jet impinging flow structure exhibits such complex nature as shock shell, plate shock and Mach disk depending on the flow parameters. Among others, the dominant parameters are the ratio of the nozzle exit pressure to the ambient pressure and the distance between the nozzle exit plane and the impinging plane. As the plate is placed close to the nozzle, the computed wall pressure at or near the jet center oscillates with large amplitude with respect to the mean value. The amplitude of wall pressure fluctuations subsides as the plate/nozzle distance increases, and the frequency of the wall pressure is estimated on the order of 10.0 KHz. Objectives of this paper are to show accurate simulation of nozzle flow itself and to demonstrate the jet flow structure when the jet interacts with a wall at a close range.
Gelatinization Characteristics of Glutinous Rice Varieties
Kwang Ho Kim,Hong Sook Park,Jae Sung Kim 韓國作物學會 1999 Korean journal of crop science Vol.44 No.1
Gelatinization characteristics of 111 glutinous rice varieties were evaluated by Rapid Visco Analyzer. Gelatinization viscosity of glutinous rice tested varied with ecotypes or varietal groups: indica, japonica, and Tongil type. Indica rice showed the highest average value of initial pasting temperature. The average values for peak, hot, and cool viscosities were highest in Tongil-type rice, and lowest in japonica rice. Japonica showed the lowest breakdown and consistency, but the highest setback value. Indica was lower in alkali digestion value (ADV), and shorter in gel length after gelatinization thanjaponica and Tongil-type. Glutinous rices tested could be divided into six groups by cluster analysis based on their gelatinization characteristics. Group I-A was mostly early maturing japonica varieties while I-B was mostly indica and Tongil-type rices. Groups II-A and II-B were consisted of very early maturingjaponica, and III-A and III-B included medium or medium late maturingjaponica varieties. Group III-A showed the lowest average values of peak, hot, cool, and consistency viscosities, and also in breakdown and setback ratios. Group I-B revealed the highest values in peak, hot, cool, breakdown, and consistency viscosities. ADV was low in groups I-A, I-B, and II-B, and gel consistency was not different among the six varietal groups. Principal component analysis using seven traits related with gelatinization produced four effective components, and the first and second components were highly correlated with all the gelatinization characters evaluated
Hong, Yoonki,Lee, Jae Seung,Yoo, Kwang Ha,Lee, Ji-Hyun,Kim, Woo Jin,Lim, Seong Yong,Rhee, Chin Kook,Lee, Sang-Do,Oh, Yeon-Mok The Korean Academy of Tuberculosis and Respiratory 2016 Tuberculosis and Respiratory Diseases Vol.79 No.2
Background: Chronic obstructive pulmonary disease (COPD) is sometimes complicated with pneumonia, but little is known about the risk factors that promote the development of pneumonia in COPD. These risk factors were evaluated in the present study. Methods: The data of 324 patients with COPD from a prospective multi-center observational cohort with obstructive lung disease were evaluated retrospectively. To identify risk factors for the development of pneumonia in COPD, the clinical and radiological data at enrollment and the time to the first episode of pneumonia were analyzed by Cox proportional hazard analysis. Results: The median follow-up time was 1,099 days and 28 patients (8.6%) developed pneumonia. The Cox analysis showed that post-bronchodilator forced expiratory volume in one second ($FEV_1$, % of predicted) and the computed tomography (CT) emphysema extent (inspiratory V950) were independent risk factors for the development of pneumonia (post-bronchodilator $FEV_1$: hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.94-1.00; p=0.048 and inspiratory V950: HR, 1.04; 95% CI, 1.01-1.07; p=0.01). Conclusion: Emphysema severity measured by CT and post-bronchodilator $FEV_1$ are important risk factors for the development of pneumonia in COPD.