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도시 소각로 시설의 고형 쓰레기 연소 후 생성된 바닥재 시료에 대한 다이옥신과 퓨란류의 분석
장윤석,홍종기,김진영,Chang, Yoon-Seok,Hong, JongKi,Kim, Jin-Young 대한화학회 1995 대한화학회지 Vol.39 No.7
다이옥신은 환경에 미량으로 존재하며 직접, 간접적인 경로를 통해 인체로 들어와 심각한 문제를 일으키는, 화학적으로 안정하고 잔류성과 독성이 강한 오염물질이다. 쓰레기 처리를 위한 소각로 시설은 다이옥신에 대한 대기오염의 주원인으로 알려져 있는데 연소시 소각로내에서와 배기가스 제어과정 중 다이옥신이 발생되는 것으로 보고되고 있다. 본 연구에서는 쓰레기 소각로에서 연소 후 생성된 바닥재 시료를 채취하여 다이옥신과 퓨란류를 조사하였다. 시료의 전처리는 EPA방법을 개선하여 불필요한 과정을 생략하면서 높은 회수율을 유지하였고 최종 정량은 고분해능 기체 크로마토그래피/고분해능 질량분석기(HRGC/HRMS)를 이용하여 분석하였다. 바닥재 시료를 분석한 전체 다이옥신의 양은 8.05 ng/g, 퓨란은 4.75 ng/g정도이었으며 2,3,7,8-TCDD는 6.93 pg/g이 검출되었고 염소원자 가 6~7개 치환된 다이옥신과 퓨란이 가장 많이 검출되는 경향을 볼 수 있었다. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are the most concerned toxic organic pollutants to human. Because of their extremely high toxicity and uncertain genotoxic potential, their determination in environmental and biological samples is of great interest. Municipal solid waste incinerator facilities have been reported as the major contributors of dioxins and furans to the environment, and their formation from combustion is a universal phenomenon, everywhere. In this study dioxins and furans were analyzed from the bottom ash produced during combustion in an municipal waste incinerator located in Seoul. The EPA method was modified for sample pretreatment: the soxhlet method was used for extraction and clean-up procedures were performed by using silica and basic alumina, excluding active-carbon. The extract was then analyzed by HRGC/HRMS. A general trend of increase in the amounts of 6∼7 chlorine-substituted dioxins and furans was observed. Total dioxins, furans and 2,3,7,8-TCDD were determined as 8.05 ng/g, 4.75 ng/g, and 6.93 pg/g, respectively.
장윤석,석창성,김영진,Chang, Yoon-Suk,Seok, Chang-Sung,Kim, Young-Jin 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.11
In order to perform leak-before-break design of nuclear piping systems and integrity evaluation of reactor vessels, full stress-strain curves and fracture resistance (J-R) curves are required. However it is time-consuming and expensive to obtain J-R curves experimentally. The objective of this paper is to modify two J-R curve prediction methods previously proposed by the authors and to propose an additional J-R curve prediction method for nuclear piping materials. In the first method which is based on the elastic-plastic finite element analysis, a blunting region handling procedure is added to the existing method. In the second method which is based on the empirical equation, a revised general equation is proposed to apply to both carbon steel and stainless steel. Finally, in the third method, both full stress-strain curve and finite element analysis results are used for J-R curve prediction. A good agreement between the predicted results based on the proposed methods and the experimental ones is obtained.
장윤석,석창성,김영진 대한기계학회 1995 대한기계학회논문집 Vol.19 No.4
In order perform leak-before-break design of nuclear piping systems and integrity evaluation of reactor vessels, full stress-strain (.sigma. - .epsilon.) curves and fracture resistance (J-R) curves are required. However it is time-consuming and expensive to obtain J-R curves experimentally. The objective of this paper is to develop two methods for J-R curve prediction. In the first method, elastic-plastic finite element analyses for a series of crack length / specimen width ratio were performed. Accordingly the load versus load line displacement (P .delta.) curve corresponding to the fracture strain is obtained and the J-R curve based on the generalized locus method is obtained. In the second method, the correlation between .sigma.-.epsilon. curves and J-R curves was statistically analyzed and an empirical equation to predict the J-R curve from the .sigma.-.epsilon. test result is proposed. A good correlation between the predicted results based on the proposed methods and the experimental ones is obtained.
장윤석,한재웅,Jang, Yun-Seok,Han, Jae-Woong 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.5
인간은 집중할 때 유발되는 특정한 뇌파가 있는 것으로 알려져 있다. 본 논문에서는 인간의 집중과 관련된 뇌파를 분석하는 것을 목표로 하여, 집중을 유발할 수 있는 도구로 시각자극을 설정하였다. 즉 시각자극으로 구성된 과제를 제시하여 피험자가 집중할 수 있도록 하였다. 피험자로부터 유발되는 뇌파는 전극의 위치에 따른 채널별로 계측하였고, 계측한 뇌파는 주파수대역별로 나누어 분석하였다. 그 중에서도 특히 SMR, Mid-beta, Theta파에 해당되는 주파수대역의 파워 스펙트럼으로 분석하였고, 그 특성을 분석한 결과를 제시하였다. It has been known that the particular brain waves are induced when a human concentrates. In our study, we aimed to analysis the brain waves related to human concentration using visual stimulus to induce the concentration. The visual stimulus tasks were presented to subjects for concentration. We measured EEG signals with several channels and analyzed the signals into several frequency bands. In the measured EEG signals, we analyzed to focus on theta waves, SMR waves and mid-beta waves. Therefore we presented the results to investigate characteristics of the EEG signals related to the human concentration.
특발성 양성 돌발성 체위변환성 어지럼 여성 환자에서골밀도 검사의 결과
장윤석,구태우,배우용,강명구,김재룡 대한이비인후과학회 2007 대한이비인후과학회지 두경부외과학 Vol.50 No.9
Background and Objectives:It has ben proposed that displaced particles arising from otoconial degeneration are the leading cause of idiopathic BPV (iBPPV)being related to a disturbance in calcium metabolism. The aim of this study was to evaluate the results of bone mineral density (BMD) measurement in women with iBPV. Subjects and Method:Fifty-four women with iBPV underwent BMD test and the results were given as a T-score. We compared the T-scores of the patients with those of 173 healthy women by age and by the presence of menopause, and we also compared the T-scores by type of iBPV among the premenopausal patients. Results:In al (p<.001). Regardles of the presence of menopause, the mean T-score in the patients was significantly lower than that in the control group (p<.001). By type of iBPV, there was no significant diference in the T-scores among the groups. Conclusion:This study demonstrates that the val-ues of BMD measurement in women with iBPV were significantly lower than in the control group regardles of age or the pres-the utility of the therapy for disturbed calcium metabolism to decrease the recurrence of iBPV. (Korean J Otorhinolaryngol-Head Neck Surg 2007 ;50 :750-4)