In the seismic evaluation of underground utility tunnels, selecting an analytical method is critical to estimating reasonable seismic responses. In simplified pseudo-static analysis methods widely applied to typical seismic design and evaluation of underground tunnels in practice, it is essential to check whether the methods provide valid results for cut-and-cover tunnels buried in shallow to medium depth. The differences between the two simplified pseudo-static methods are discussed in this study, and the analysis results are compared to those obtained from FLAC models. In addition to the analysis methods, seismic site classification, overburden soil depth, and sectional configuration are considered variables to examine their effects on the seismic response of underground utility tunnels. Based on the analysis results, the characteristics derived from the concepts and details of each simplified model are discussed. Also, general observations are made for the application of simplified analysis methods.

국내 유통 중인 콜라겐 제품 120건을 대상으로 중금속 4종(납, 카드뮴, 비소, 수은) 함량에 대해 조사하였다. 수 은은 금아말감화법을 이용한 수은분석기로 분석하였고 납, 카드뮴, 비소는 ICP-OES를 이용하여 분석하였다. 검사 결 과 납의 평균 함량은 0.097±0.055 mg/kg이었고 건강기능 식품, 기타가공품, 음료류, 과·채가공품에서 각각 평균 0.108±0.052mg/kg, 0.084±0.053 mg/kg, 0.131±0.047 mg/ kg, 0.149 mg/kg 농도로 검출되었다. 카드뮴의 평균 함량 은 0.026±0.011 mg/kg이었으며 검출된 제품은 모두 건강 기능식품이었다. 비소의 평균 함량은 0.097±0.048 mg/kg 이었고 건강기능식품, 기타가공품, 과·채가공품에서 각각 평균 0.091±0.055 mg/kg, 0.133 mg/kg, 0.086 mg/kg 농도 로 검출되었다. 수은의 평균 함량은 0.0025±0.0016 mg/kg 으로 건강기능식품, 기타가공품, 과·채가공품, 캔디류에서 각각 평균 0.0012 mg/kg, 0.0028±0.0018 mg/kg, 0.0013 mg/kg, 0.0031 mg/kg 농도로 검출되었다. 중금속 기준·규 격이 있는 음료류(납 0.3 mg/kg, 카드뮴 0.1 mg/kg) 및 캔 디류(납 0.2 mg/kg)는 모두 기준 이하로 검출되어 적합하 였다. 기준·규격이 없는 제품도 국내외 식품의 중금속 기 준과 보고된 식품 중금속 함량과 비교하였을 때 비교적 안전한 수준이라고 판단되었다.

The purpose of this study was to investigate the contents of apigenin and luteolin in vegetables mainly distributed and consumed in Korea. In this study, the contents of apigenin, apigenin-7-O-glucoside, luteolin, and luteolin-7-O-glucoside in vegetables were surveyed by using liquid chromatography coupled to mass spectrometry (LC-MS/MS). According to the analysis of 27 items (91 samples) in vegetables, the content of total apigenin (the sum of apigenin and apigenin-7-O-glucoside) was quantified in 8 out of the 27 items in vegetables, followed by pepper leaves, parsley, celery, chamnamul, foremost mugwort, and perilla leaves. The content of total luteolin (the sum of luteolin and luteolin-7-O-glucoside) was found in 11 of the 27 items in vegetables, followed by pepper leaves, dandelion, celery, red lettuce, foremost mugwort, and perilla leaves. Celery was divided into stalks and leaves for comparing the contents of apigenin and luteolin. Celery showed higher contents of apigenin and luteolin in leaves than in stalks.

본 연구는 2019년 국내에서 유통되는 수산물 198건(학교급식 수산물 121건, 유통 77건)에 대하여 히스타민 등 8종의 바이오제닉아민(BAs) 함량을 분석하였다. 또한, 삼치, 고등어, 연어에 대하여 시간, 온도와 염 처리에 따른 BAs 함량 변화를 관찰하였다. 수산물의 평균 히스타민 함량은 0.4±2.3 mg/kg이었으며, 모두 히스타민 기준 200 mg/kg이내 이었다. MOE를 산출하여 위해성을 평가한 결과, MOE가 1 이상으로 학교급식 수산물은 안전한 것으로 평가되었다. 시간과 온도에 따른 생선의 BAs 함량 변화는 시간과 온도가 증가함에 따라 증가하는 경향 을 나타내었으며, 히스타민 함량이 30oC에서 144 mg/kg(삼치, 36시간)과 308 mg/kg(고등어, 24시간)로 급격히 증가하였다. 또한, 삼치, 고등어와 연어를 4oC와 -20oC에 보관한 결과, 4oC에서는 3일까지, -20oC에서는 14일까지 모두 히스타민이 검출되지 않았다. 생선의 염 처리에 따른 BAs 함량 변화는 염을 처리한 삼치와 고등어에서 염을 처리하지 않은 삼치와 고등어보다 히스타민 등 BAs 함량이 낮게 나타났다.

장과류의 방사능 안전성 확보를 위해 2016년부터 2018년까지 경기도 내 유통 중인 장과류 및 가공식품 15품목 258건을 수거하여 방사능 오염을 분석하였다. 방사능 분석은 게르마늄 감마핵종 분석기를 이용하였으며, 인공 방사성 물질인 요오드(131I)와 세슘(134Cs, 137Cs)을 분석하였다. 모든 제품에서 131I와 134Cs은 MDA (Minimum Detectable Activity)값 이상으로 검출되지 않았고, 39건에서 0.69-808.90 Bq/kg 범위로 137Cs이 검출되었다. 국내산 제품 6건은 0.70- 3.29 Bq/kg 범위에서 검출되었지만, 원재료는 모두 수입산 이었다. 수입산 제품 33건은 0.69-808.90 Bq/kg 방사능 농도를 나타내었으며, 폴란드산 블루베리 분말 제품 1건(808.90 Bq/kg) 및 링곤베리 분말 제품 2건(103.93, 188.46 Bq/kg)은 국내 방사성 세슘의 허용 기준을 초과하였다. 이러한 결과는 식품 안전 확보를 위해 수입산 장과류와 장과류 가공식품에 대한 방사능 검사 강화와 함께 수입 과정에서 더 철저한 관리가 필요한 것으로 판단된다.

As many existing research fields are matured academically, researchers have encountered numbers of academic, social and other problems that cannot be addressed by internal knowledge and methodologies of existing disciplines. Earlier, pioneers of researchers thus are following a new paradigm that breaks the boundaries between the prior disciplines, fuses them and seeks new approaches. Moreover, developed countries including Korea are actively supporting and fostering the convergence research at the national level. Nevertheless, there is insufficient research to analyze convergence trends in national R&D support projects and what kind of content the projects mainly deal with. This study, therefore, collected and preprocessed the research proposal data of National Research Foundation of Korea, transforming the proposal documents to term-frequency matrices. Based on the matrices, this study derived detailed research topics through Latent Dirichlet Allocation, a kind of topic modeling algorithm. Next, this study identified the research topics each proposal mainly deals with, visualized the convergence relationships, and quantitatively analyze them. Specifically, this study analyzed the centralities of the detailed research topics to derive clues about the convergence of the near future, in addition to visualizing the convergence relationship and analyzing time-varying number of research proposals per each topic. The results of this study can provide specific insights on the research direction to researchers and monitor domestic convergence R&D trends by year.

The physiologically advantageous aspects of green tea have been identified recently and green tea has been a favorite drink of many people. Due to the increased awareness of green tea’s positive effects on human health, the demand for foods containing green tea has increased. This has led to the development of diverse green tea-related beverages; thereby many companies in Korea have put a wide variety of manufactured green tea beverages on the market. However, the components within green tea beverages have not been examined in Korea yet. In this study, we investigated the contents of the physiologically functional materials found in green tea, such as catechin, catechin gallate, epicatechin, epicatechin gallate, epigallocatecin gallate, gallocatechin gallate and caffeine. Fifty-six green tea products purchased from the local grocery stores and cafes were analyzed using high performance liquid chromatography (HPLC) analysis. As a result, all tested products contained catechin and caffeine, although the amount of each component was largely different. The total amount of catechin derivatives in the manufactured green tea beverages purchased from cafes was 263.17 mg/L, while they were 61.99 mg/L in the beverages purchased from the local grocery stores. And, to the almost samples the amount of caffeine was proportional to the amount of catechin.

The risk-based assessment, also called time-based assessment of structure is usually performed to provide seismic risk evaluation of a target structure for its entire life-cycle, e.g. 50 years. The prediction of collapse probability is the estimator in the risk-based assessment. While the risk-based assessment is the key in the performance-based earthquake engineering, its application is very limited because this evaluation method is very expensive in terms of simulation and computational efforts. So the evaluation database for many archetype structures usually serve as representative of the specific system. However, there is no such an assessment performed for building stocks in Korea. Consequently, the performance objective of current building code, KBC is not clear at least in a quantitative way. This shortcoming gives an unresolved issue to insurance industry, socio-economic impact, seismic safety policy in national and local governments. In this study, we evaluate the comprehensive seismic performance of an low-rise residential buildings with discontinuous structural walls, so called piloti-type structure which is commonly found in low-rise domestic building stocks. The collapse probability is obtained using the risk integral of a conditioned collapse capacity function and regression of current hazard curve. Based on this approach it is expected to provide a robust tool to seismic safety policy as well as seismic risk analysis such as Probable Maximum Loss (PML) commonly used in the insurance industry.

본 연구는 식품접객업소 등에서 사용되는 94건의 물수건(위생처리업소 39건, 식품접객업소 55건)에 대하여 위생 지표세균, 중금속, 염소부산물 등에 대한 안전성을 조사하였다. 중금속 안전성 조사결과 납은 불검출 ~ 0.41 mg/kg(불검출 75건), 비소는 불검출 ~ 0.25 mg/kg(불검출 93건), 카드뮴은 불검출 ~ 0.01 mg/kg(정량한계 미만 7건, 불검출 87건), 수은은 0.003 mg/kg ~ 0.09 mg/kg, 6가크롬은 모든 시료에서 검출되지 않았다. 이 중 납의 검출량이 가장 많았으나, 가장 높은 검출량인 0.41 mg/kg조차 납 규격기준(20 mg/kg 이하)의 2.1%로 매우 낮은 수준이었다. 미생물 안전성의 경우 대장균은 모든 시료에서 음성이었으며, 일반 세균수는 43건 양성이고, 그 중 24건은 규격기준을 초과 하였다. 물수건의 포장상태는 세균의 오염 및 물수건 간의 교차오염에 큰 영향을 끼치는 것으로 확인할 수 있었다. 포장에 따른 미생물 오염 비교결과는 덕용포장이고 개봉포장일 때 세균의 오염이 가장 높았다. 수거 시 위생물 수건의 수분함량과 미생물의 상관관계를 확인해본 결과 유의성은 없었으며, 각 시료별 수분함량은 50.0% ~ 77.0%(평균 61.9%)이었다. 물수건 소독에 사용되는 염소화합물 로부터 유래되는 염소부산물(클로라이트, 클로레이트)은 88건 중 17건(19.3%)에서 검출되었다. 본 연구결과는 물수건의 제조업 및 식품접객업 종사자의 교육 및 안전관리 정책의 기초자료로 활용할 수 있을 것으로 생각된다.

This study was conducted to evaluate the microbiological hazard on nursery school children's hands and to investigate the reduction effect of hand washing education. A total of 59 nursery school children's hands were tested. The average number of total aerobic bacteria was 3.72 ± 0.38 log CFU/hand. Five children's hands(2 male and 3 female) were positive(14.3%) for the coliform bacteria. These results showed that hand washing education are required repetitively. Among the pathogenic bacteria tested in this study, Staphylococcus aureus and Bacillus cereus were detected in 9(25.7%) and 16(45.7%) out of 35 their hands, respectively. Twelve out of sixteen B. cereus isolates(70.0%) produced enterotoxin. The results indicate that the hand hygiene of nursery school children needs to be improved. Comparing before and after hand washing in educated and non-educated group, the reduction effect of total aerobic bacteria on their hands was 0.42 and 0.60 log CFU/hand, respectively. The educated group showed 0.18 log CFU/hand higher reduction effect than non-educated group but microorganism did not eliminate perfectly. From the results, using a hand sanitizer after washing with soap and the continuous hand washing education are required to control the contaminated bacteria on nursery school children's hands.