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알루미나에 의한 Fission 몰리브덴의 흡착과 탈착 특성
이종대,정원명,조경태 한국산업안전학회 1997 한국안전학회지 Vol.12 No.3
Mo-99 (Molybdenum) is the only source of Tc-99m(Technetium) which is most frequently used in nuclear medical diagnostics and the demand is on the increase recently. Separation and refining of Mo-99 was investigated by adsorption and desorption on alumina. At pH=0.63, adsorption isotherm of Mo was fitted by Redlich & Peterson equation using the adsorption experimental data. It was found that the pore diffusion model (D_p=1.4×10^(-6)㎝/s, K_f = 0.4㎝/s) agreed well with batch adsorption experimental data. RTDs(Residence Time Distributions) were measured and axial dispersion coefficients were obtained in the fixed bed adsorber according to the changes of the flow rate using 0.05%-NaCl. From the adsorption experimental data, it was shown that the behavior of breakthroughs depended on flow rate. Mo recovery yield was increased its adsorption flow rate was increased and desorption flow rate was decreased.
감마선 조사에 의한 초고분자량 폴리에틸렌의 기계적 특성 변화
이종대(Jong-Dae Lee),정선환(Seon-Hwan Cheong),최성대(Seong-Dae Choi),김현묵(Hyun-Mook Kim) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.3
Uniaxial tension and compression test were conducted on conventional and crosslinked ultra-high molecular polyethylene (UHMWPE) all prepared from the same lot of medical grade GUR 1050. The conventional materials were unirradiated and gamma irradiated with 25kGy~200kGy. Gamma irradiated processing was found to significantly impact the crystallinity, and hence the mechanical behavior, of the highly crosslinked UHMWPE. The crystallinity and radiation dose wrer key predictors of the uniaxial yielding, hardness, plastic flow, and failure properties of conventional and highly crosslinked UHMWPE. The correlation model from experiments would be the basic information to design the liner of artificial joint.
Analysis of Prognostic Factors in Malignant External Otitis
이상국,이세아,선상우,정재현,이종대,최재영,김보경 대한이비인후과학회 2017 Clinical and Experimental Otorhinolaryngology Vol.10 No.3
Objectives. Malignant external otitis (MEO) is a potentially fatal infection of the external auditory canal, temporal bone, and skull base. Despite treatment with modern antibiotics, MEO can lead to skull base osteomyelitis. Until now, there have been few studies on the prognostic factors of MEO. Methods. We performed a retrospective study to identify prognostic factors of MEO, and a meta-analysis of other articles investigating MEO. On the basis of disease progression the 28 patients in our study were divided into ‘controlled’ and ‘uncontrolled’ groups, consisting of 12 and 16 patients, respectively. We identified three categories of prognostic factors: those related to patient, disease, and treatment. We compared these prognostic factors between the controlled and uncontrolled groups. Results. In our study, the duration of diabetes mellitus (DM), presence of inflammatory markers (C-reactive protein and erythrocyte sedimentation rate), and computed tomography or magnetic resonance imaging findings influenced the prognosis of MEO. In contrast, prognosis was unrelated to age, gender, mean glucose level, hemoglobin A1c level, pathogen, comorbidity, or cranial nerve involvement. No factor related to treatment modality was correlated with prognosis, such as surgery, steroid therapy, or interval to the first appropriate treatment. Cranial nerve involvement has been proven to be associated with disease progression, but the relationship between cranial nerve involvement and the prognosis of MEO remains controversial. As a part of this study, we conducted a meta-analysis of cranial nerve involvement as a prognostic factor of MEO. We found that cranial nerve involvement has a statistically significant influence on the prognosis of MEO. Conclusion. We found that glycemic control in diabetes mellitus, cranial nerve involvement, and the extent of disease determined from various imaging modalities influence the prognosis of MEO. We suggest that significant prognostic factors should be monitored to determine the prognosis of patients with MEO.
이세아,이상국,선상우,정재현,이종대,김보경 대한이비인후과학회 2018 대한이비인후과학회지 두경부외과학 Vol.61 No.1
Background and Objectives Children with unilateral sensorineural hearing loss (USNHL) are not actively evaluated by physicians. The diagnostic tool for evaluation of USNHL is also controversial, and no strategy for diagnosing USNHL through imaging studies has been established. We examined the results of temporal bone computed tomography (TBCT) imaging and magnetic resonance imaging (MRI) studies on children with USNHL. Subjects and Method Eighty-nine patients with USNHL were reviewed. Of these patients, 21 underwent both TBCT and MRI, 51 underwent temporal MRI only, and 17 underwent TBCT only. Results The etiology of USNHL were determined through imaging studies in 20 patients. The most common abnormal finding (65%) was a narrow internal auditory canal identified on TBCT and cochlear nerve aplasia on temporal MRI. Incomplete partition (20%), common cavity (10%), and labyrinthitis ossificans (5%) were also observed in imaging studies. The hearing threshold was lower in USNHL patients with normal findings (76.1±28.7 dB) than in USNHL patients with abnormal findings on TBCT or temporal MRI (100.1±22.3 dB). Conclusion Cochlear and cochlear nerve abnormalities can be detected through imaging studies in approximately 25% of patients with USNHL. Therefore, we suggest that children should undergo TBCT when USNHL is confirmed through audiologic evaluation. Korean J Otorhinolaryngol-Head Neck Surg 2018;61(1):9-14