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무릎인대 길이 대 무릎골 길이의 비율 : 굴곡 및 신전 자기공명영상비교
서재승 대한영상의학회 1998 대한영상의학회지 Vol.38 No.5
Purpose : To determin whether radiographic assessment of patella position abnormalities (such as patella altaor baja) using the 'patellar tendon : patella ratio' (Insall & Salvati's method) can be applied to flexion andextension sagittal MR images of the knee Materials and Methods : Both flexion (55-90。, mean 62。) and extensionT2-weighted sagittal images of 58 knees (54 patients;age:19-72 years:M:F=40:18 were obtained and reviewed by meansof routine lateral radiographs (flexion of knees:30-60。). Patellar tendon and diagonal length were measured onroutine radiographs and on flexion and extension MR images;length was measured by sagittal T2-weighted MR imagingfrom the inner aspect of patellar insertion to the inner asspect of tibial insertion, an approach whichdemonstrated the even thickness of the patellar tendon and the greastest diameter of the patella. Usingcorrelation analysis, the ratio of patellar tendon to diagonal length was compared between examination methods andbetween the non-wavy and wavy forms of patellar tendon. Results : The mean length of the respectirely, 'patella,patellar tendon and patellar tendon to patella ratio' were 4.15$\pm$0.38, 4.04$\pm$0.49 and 0.9$\pm$0.12, respectively, onroutine radiographs; 4.32$\pm$0.36, 3.8$\pm$0.47 and 0.89$\pm$ 0.12, respectively, on flexion MR images;and 4.3$\pm$0.36,3.93$\pm$0.44 and 0.92$\pm$0.12, respectively on extension MR images. Between these three different modes of assessment,a high degree of correlation of mean patella length (r=0.89-0.92) and of mean patellar tendon length (r=0.71=0.85)were found. In addition, correlation of 'patella to patellar tendon ratios' was excellent : radiographs andflexion MRimages(r=0.76);radiographs and extension MR images(r=0.76);flexion and extension MR images(r=0.84).According to the form of patellar tendon, radiographs correlated better with extension MR images (r-0.71) thanwith flexion images (r=0.62) in the non-wavy form of patellar tendon, whereas in the wavy form, correlation withflexion images (r=0.83) was better than with extension images(r=0.78). Conclusion : MR asessment of 'patellartendon to patella ratio's correlated well with radiographic assessment, and the latter can therefore be used forthe evaluation of abnormal patellar position. Radiographs correlated better with extension MR images in thenon-wavy form of patellar tendon, whereas in the wavy form, correlation with flexion images was better.
웨스팅하우스형 원자력발전소 가압기 방출 탱크의 실시간 시뮬레이션을 위한 전문모델 개발
서재승,전규동 한국시뮬레이션학회 2004 한국시뮬레이션학회 논문지 Vol.13 No.2
The thermal-hydraulic model ARTS which was based on the RETRAN-3D code adopted in the domestic full-scope power plant simulator which was provided in 1998 by KEPRI. Since ARTS is a generalized code to model the components with control volumes, the smaller time-step size should be used even if converged solution could not get in a single volume. Therefore, dedicated models which do not force to reduce the time-step size are sometimes more suitable in terms of a real-time calculation and robustness. In the case of PRT(Pressurizer Relief Tank) model, it is consist of subcooled water in bottom and non-condensable gas in top. The sparger merged under subcooled water enhances condensation. The complicated thermal-hydraulic phenomena such as condensation, phase separation with existence of non-condensable gas makes difficult to simulate. Therefore, the PRT volume can limit the time-step size if we model it with a general control volume. To prevent the time-step size reduction due to convergence failure for simulating this component, we developed a dedicated model for PRT. The dedicated model was expected to provide substantially more accurate predictions in the analysis of the system transients. The results were resonable in terms of accuracy, real-time simulation, robustness and education of operators, complying with the ANSI/ANS-3.5-1998 simulator software performance criteria and RETRAN-3D results.