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        검색결과 4,107

        441.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 가미수미원(백하수오 10 g,; 당귀 6 g; 구기자 8 g; 화피 6 g; 선태 3 g; 홍화 2 g)에 방기(Sinomenium acutum R.) 4 g의 첨가 여부에 따라 각각 열수추출물은 GS±SC(DW), 80% 에탄올 추출물은 GS±SC(EtOH)로 표기 하였다. 각 추출물은 항산화를 측정하기 위해 다음과 같은 연구를 수행하였 다. HPLC를 통한 방기 지표물질 함량측정, 중금속 검사 기준 측정, ABTS/DPPH 라디칼 소거능 측정, SOD 유사 활성능 측정, ROS 및 NO 생성량을 측정하였다. 방기 지표물질 중 sinomenine의 함량은 열수 추출물에서, decursin은 에탄올 추출물에서 더 높게 확인되었다. 중금속 측정 결과 기준치 적합으로 확인되었다. ABTS/DPPD 라디칼 소거능을 측정한 결과 GS+SC(EtOH)의 소거능이 가장 높게 나왔으며, 상대적으로 열수보다 에탄올 추출이 라디칼 소거율이 높게 확인되었다. 그러나 SOD의 경우 열수 추출에서 상대 적으로 유사 활성능이 높게 확인되었다. ROS 생성의 경우 열수 추출물이 에탄올 추출에 비해 유의하게 감소시켰으며, NO의 생성은 에탄올 추출물이 상대적으로 더 유의하게 감소시키는 것을 확인하였다. 본 연구 결과에서 GS+SC(EtOH)이 라디컬 소거능 및 NO 감소를 높게 나타낸 것으로 확인되어 산화적스트레스 후, 생성된 활성산소의 제거에 좀 더 영향을 미치는 것으로 판단된다. 향후 지속적인 효능 심화 연구를 통해 조성물을 활용한 화장품 및 기능성 원료의 소재로서의 가능성이 높을 것으로 사료된다.
        4,300원
        442.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Small-sized heater is usually used to make the hot water in resting place, factory, household affairs and so on. One of methods to obtain hot water in short time is known as using instantaneous electric water heater. In this study, numerical analysis for small-sized hot water heater with straight double tube-type was tried to achieve the basic design data. This study aims to investigate the characteristics of thermal flow, for instance, such as pressure difference, outlet mean temperature and velocity, due to clearance. As the clearance is decreased, outlet mean temperature and pressure difference(Pmax.-Pmin.) are increased. Therefore appropriate relations between area of heat source and pressure difference should be set up. Further small-sized hot water heater in this study must be equipped with electric device capable of heating over 90℃.
        4,000원
        443.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        가막만 북서내만해역에서 매년 여름 발생하는 빈산소수괴는 해양환경에 악영향을 미쳐왔다. 따라서, 본 연구는 빈산소수괴 발 생시기의 집중적인 현장조사 결과를 바탕으로 다중회귀분석(MRA)을 이용하여 빈산소수괴의 종합적인 발생 메커니즘을 밝혀내고, 그 주 요인에 따른 빈산소수괴 관리방안의 방향성을 모색하였다. 그 결과, 2017년 첫 빈산소수괴는 6월 26일에 발생하였으며, 기상 조건에 의한 수온약층의 형성과 퇴적된 유기물의 영향으로 형성되었다. 이어 7월 12일에는 강우량의 증가에 의한 염분약층의 형성으로, 조사 시기 중 빈산소수괴가 수직 및 수평적으로 가장 크게 확장되었다. 그리고, 8월 8일에는 소량의 강우로 빈산소수괴가 크게 약화되었으며, 이때 주 요인은 Chlorophyll-a 농도 증가(식물플랑크톤 증식)과 퇴적된 유기물이었다. 그리고, 약 1주일 후인 8월 16일에는 많은 강우량에 기인한 매우 안정된 염분약층과 Chlorophyll-a 농도 증가(식물플랑크톤 증식)에 의해 크게 확장된 빈산소수괴가 재발생하였다. 이후 9월 13일의 빈산 소수괴 소멸시기에서는 빈산소수괴가 해저 면을 따라 얕게 확장되었으며, 퇴적된 유기물에 의해 주로 영향을 받은 것으로 나타났다. 이는 빈산소수괴 관리를 위해서는 퇴적된 유기물의 개선뿐만 아니라 성층의 완화 기술이 필요함을 암시하였다.
        4,500원
        444.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the content of water-soluble vitamins such as vitamin B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B12 (cyanocobalamin), and C (ascorbic acid) in dishes containing meat and seafood consumed in Korea were determined by high-performance liquid chromatography (HPLC) with ultraviolet and fluorescence detection. All analyses were performed under strict quality control of vitamins B1, B2, B3, B5, B6, B7, B12, and C. The highest content of vitamin B1 was observed in Bugeo-gangjeong (1.373 mg/100 g) and the highest level of vitamin B2 (5.162 mg/100 g) was found in pig liver. Bugeo-gangjeong showed the highest content of vitamin B3 (21.676 mg/100 g), and kkomak-muchim contained considerable amounts (43.310 mg/100 g) of vitamin B5. Vitamin B6 was not detected in most seafood dishes except for yangnyeom myeongran-jeot (0.274 mg/100 g) and was present at low levels or not present at all in meat dishes. The highest content of vitamin B7 was 6.506 μg/100 g in saeu-jeon and kkomak-muchim showed the highest content (21.132 μg/100 g) of vitamin B12. The highest content of vitamin C was in yangnyeom myeongran-jeot (84.508 mg/100 g). In addition, the analysis methods of each water-soluble vitamin were verified. These results showed that seafood-based ingredients in several dishes could be a good source of water-soluble vitamins.
        4,000원
        445.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the intake status of beverages and water in Korean adults using data from the 8th National Health and Nutrition Examination Survey. The ‘total water’ intake was 2,250.6 g for men and 1,871.2 g for women. Men and women consumed an average of 314.9 g of ‘total beverages’, of which ‘coffee’ was the largest at 107.5 g, followed by ‘others’(65.4 g), ‘milk’ (44.8 g), ‘soda’ (44.1 g), ‘teas’ (20.9 g), and ‘fruits and vegetables’ (18.5 g). The intake of ’plain water’ was 1,059.9 g, and the intake of ’water from food’ consumed was 547.3 g. The ‘total water’ intake decreased with increasing age in males and females (p<0.001). Both men and women showed a tendency toward increased ‘total water’ intake as income levels increased. ‘Plain water’ intake accounted for 51.4% of the ‘total water’ intake in males and females. The intake of all nutrients significantly increased from the Q1 group to the Q4 group by quartile ranges of total water intake. The results of this study showed that the intake of healthy water should be considered, and care and educational programs are needed, especially for older people, to ensure adequate water intake.
        4,200원
        446.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Water treatment process simulator is the tool for predicting sequential changes of water quality in a train of unit processes. This predicts the changes through governing equations that represent physicochemical performance of each unit processes with an initial and boundary conditions. Since there is no operational data for the design of a water treatment facility, there is no choice but to predict the performance of the facility by assuming initial and boundary conditions in virtual reality. Therefore, a simulator that can be applied in the design stage of a water treatment facility has no choice but to be built as a numerical analysis model of a deductive technique. In this study, we had conducted basic research on governing equations, inter-process data-flow, and simulator algorithms for the development of simulators. Lastly, this study will contribute to design engineering tool development research in the future by establishing the water treatment theory so that it can be programmed in a virtual world and suggesting a method for digital transformation of the water treatment process.
        4,800원
        447.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pilot-scale coagulation and sedimentation processes were operated to investigate the T-P (Total phosphorus) removal efficiency. A multiple regression model was also derived to predict the water quality improvement effect with river water characteristics. The inflow rates for the pilot-scale facility were 157–576 m3/day, and the coagulant doses were in the range of 13.7–58.5 mg/L (average 38.9 mg/L) for PAC (Poly alum chloride) and 16.5–62.1 mg/L (average 36.0 mg/L) for alum. The results found that the influent BOD (Biochemical oxygen demand) and T-P concentrations were 4.9 mg/L and 0.115 mg/L, and the removal efficiencies were 52.7% and 59.4%, respectively. T-P removal efficiencies on wet weather days were higher by 10% than dry weather days because influent solids influenced T-P's coagulation process. The pH of river water was 6.9–7.8, and the average pH was 7.3. Although the pH variation was not significant, the trend showed that the treatment efficiency of T-P and PO4-P removal increased. Thus, the pH range considered in this study seems to be appropriate for the coagulation process, which is essential for phosphorous removal. The T-P removal efficiencies were 19.6–93.3% (average 59.2%) for PAC and 16.4–98.5%(average 55.9%) for alum; thus, both coagulants showed similar results. Furthermore, the average coagulant doses were similar at 42.4 mg/L for PAC and 41.3 mg/L for alum. When the T-P concentration of the effluent was compared by the [Al]/[P] ratio, the phosphorus concentration of the treated water decreased with an increasing [Al]/[P] ratio, and the lowest T-P concentration range appeared at the [Al]/[P] ratio of 10–30. A seasonal multiple regression analysis equations were derived from the relationships between 10 independent and dependent variables (T-P concentration of effluent). This study could help lake water quality maintenance, reduce eutrophication, and improve direction settings for urban planning, especially plans related to developing waterfront cities.
        4,300원
        448.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기후 변화는 비정상적인 날씨 패턴을 야기하며 연간 강수량에 지대한 영향을 미친다. 이와 더불어 산업화의 가속화는 에너지 수요를 증가시키며 석유화학 산업폐수의 누수와 유조선의 유출을 초래함으로써 수질 오염을 악화시킨다. 이러한 부정적인 여건 속에서 정수를 효율적으로 추출해내는 해결책을 강구하는 것이 요구된다. 기름/물 분리를 위해 화학적 침전 및 흡착에 의한 분리 등과 같은 방식을 운용할 수 있지만 분리막 기술이 비용 및 에너지 측면에서 더 효율적이다. 분리막의 양친성은 전기 전도성과 친수성이 뛰어난 MXene이라는 2차원소재를 도입하여 향상시킬 수 있다. 본 총설에서는 향상된 분 리막 성능의 사례를 크게 순수 MXene이 적용된 사례와 변형된 MXene이 적용된 사례로 나누어진 목차로 전개할 것이다. 복합 분리막을 제조하기 위해 다양한 고분자가 사용되었으며 각 사례에서 MXene은 특정 용도에 적합한 특성을 더욱 강화시켜 주었다.
        4,200원