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        검색결과 62

        6.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to find out the optimal solvent extraction method [Distilled water (DW), 70% ethanol, 99% ethanol] of mushrooms, including Pleurotus ostreatus (Jacq.) Que, Pleurotus eryngii and Flammulina velutipes and improve their usability as natural antioxidants. To analyze antioxidant activities in each mushroom, total polyphenol, flavonoid contents, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2?-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical (ABTS+) and fluorescence recovery after photobleaching (FRAP) were measured. All mushrooms showed the highest total polyphenol contents in DW mushroom extract (p<0.001). Total flavonoid contents were the highest in P. eryngii and F. velutipes DW and 70% ethanol mushroom extracts (p<0.05). All mushrooms showed the highest activities using DPPH and FRAP assays in the DW extraction method (p<0.001). P. ostreatus (Jacq.) Que and P. eryngii showed the highest ABTS+ radical scavenging activity in the DW extraction method, and F. velutipes showed the highest activity in the 70% ethanol extraction method (p<0.001). As a result of comparing IC50 values of DPPH and ABTS+ radicals and FRAP EC50 values, the DW P. ostreatus (Jacq.) Que extract showed high antioxidant activities (p<0.001). Pearson's correlation between total polyphenol contents and antioxidant activities showed a positive correlation in all mushrooms (p<0.01). Therefore, extraction of the mushrooms with DW can enhance the extraction of effective bioactive substances and antioxidant activity.
        4,200원
        7.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the early 1960s, US Air Force lost missile launch bases during ICBM development by a defect in the missile design and operation plan. U.S. DoD realized the limitation of the existing accident prevention method. Therefore, the weapon development required system safety activity, and procurement projects of U.S. DoD applied MIL-STD-882(System Safety). Development projects of U.S. DoD more emphasized the importance of system safety after the space shuttle Challenger exploded in 1986. Currently, Airworthiness certification for military aircraft uses system safety to minimize accidents. The domestic defense aviation R&D projects also use the system safety for the airworthiness certification. However, non-aviation weapon R&D projects rarely applied system safety. This paper presents a system safety application method for domestic weapon R&D projects by studying the U.S. military standards/organizations and domestic defense aviation projects.
        4,000원
        8.
        2021.11 구독 인증기관 무료, 개인회원 유료
        In this paper, we propose dead pixel detection and compensation method using nonlinear estimator for infrared camera. Infrared camera has dead pixel that is abnormal output values due to complex factors such as manufacturing process, electronic parts and so on. Dead pixels are able to affect detecting a small target. So, It needs detection and Compensation process. However, after Compensation, some dead pixels are remained and detected by the human. They are soft dead pixel. The key idea of this proposed method, detecting soft dead pixels, is that design a nonlinear estimator using image data characteristics. This propose is able to not only detect soft dead pixels but also pixel Compensation that reflects infrared camera output characteristics well.
        3,000원
        10.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to find out the bakery processing suitability of maca and to develop rice-based processed foods. We investigated the antioxidant activity and physicochemical properties of rice cookies prepared with the addition of maca (Lepidium meyenii) powder (1%, 2%, 3%, and 4% of the total materials). We observed an increase in the total polyphenol and flavonoid content, and DPPH-ABTS+ radical scavenging activity of the rice cookies as the proportion of added maca powder increased (p<0.05). The quality characteristics such as the “a” value, “b” value, and the hardness of the cookies increased with an increase in the proportion of maca powder (p<0.05) in the cookie, whereas the moisture content, pH of the dough, spread ratio, loss rate, leavening rate, and “L” values showed a significant decrease (p<0.05). In the sensory evaluation results, consumer acceptability showed a significantly higher value in the 2% maca cookie group (p<0.05), and the characteristic intensity rating (color, flavor, bitterness) increased as the proportion of maca added to the cookie increased (p<0.05). Therefore, this suggests that adding 2% maca powder as the functional ingredient in rice cookies can result in rice bakery products with excellent qualities.
        4,000원
        12.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study sought to investigate the effects of heat-moisture treatment (HMT) and ethanol treatment (EOH) for improving the quality and storage stability of Tteokbokki Tteok. The quality characteristics were evaluated by moisture, pH, color, texture profile analysis, and observing the microbial properties after the heat-moisture treatment or ethanol treatment. As the storage period increased, the moisture content of Tteokbokki Tteok tended to decrease except for the HMT group (p<0.05) while the pH did not show significant variation except for the EOH group (p<0.05). While measuring the color, the L-value tended to increase in all groups during the storage period. The a-value and the b-value showed the highest values in the HMT group and the control (CON) group, respectively. In the texture profile analysis, all groups showed a significant tendency to increase levels of hardness and chewiness as the storage period increased (p<0.05). The HMT group showed an increase in hardness and adhesiveness, which are characteristics of the HMT treatment. The results of examining the microbial properties of Tteokbokki Tteok showed that the total microbial count in the HMT group was 4.52 on the 8th day of storage, which was lower than the level in the CON group and the EOH group on the 4th day of storage. Yeast and mold were not measured during the storage period. Thus the results of this study showed that when manufacturing Tteokbokki Tteok, the heat-moisture treatment of rice powder increased the storage stability by delaying microbial growth and also had positive effects on quality.
        4,000원
        13.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The metal plating industry produces a large amount of wastewater generally containing heavy metals with various chemical compounds; as such, treating the wastewater is both an environmental and an economic challenge. A vacuum evaporation system has been developed to effectively reduce the volume of plating wastewater. However, the gas stream discharged from the distillation unit of the evaporator is often contaminated with high concentrations of odorous compounds such as ammonia and dimethyl disulfide (DMDS). In this study, a non-thermal plasma process operated in wet conditions was applied to remove the odorous compounds, and it showed high removal efficiencies of greater than 99% for ammonia and 95% for DMDS. However, the gas flowrate more substantially affected the efficiency of ammonia removal than the efficiency of DMDS removal, because the higher the gas flowrate, the shorter the contact time between the odorous compound and the mist particles in the wet plasma reactor. The analyses of the maximum removal capacity indicated that the wet non-thermal plasma system was effective for treating the odorous compounds at a loading rate of less than 20 mg/m3/min even though the lowest amount of electrical power was applied. Therefore, the wet-type non-thermal plasma system is expected alleviate to effectively abate the odor problem of the vacuum evaporator used in the treatment of plating wastewater.
        4,000원
        14.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Odor compounds and air-born microorganisms are simultaneously emitted from various aeration processes such as aerobic digestion, food-waste compositing, and carcass decomposition facilities that are biologically-treating wastes with high organic contents. The air streams emitted from these processes commonly contain sulfur-containing odorous compounds such as hydrogen sulfide(H2S) and bacterial bioaerosols. In this study, a wet-plasma method was applied to remove these air-born pollutants and to minimize safety issues. In addition, the effects of a gas retention time and a liquid-gas ratio were evaluated on removal efficiencies in the wet-plasma system. At the gas reaction time of 1.8 seconds and the liquid-gas ratio of 0.05 mLaq/Lg, the removal efficiency of bioaerosol was approximately 75 %, while the removal efficiency of H2S was lower than 20 %, indicating that the gaseous compound was not effectively oxidized by the plasma reaction at the low liquid addition. When the liquid-gas ratio was increased to 0.25 mLaq/Lg, the removal efficiencies of both H2S and bioaerosol increased to greater than 99 %. At the higher liquid-gas ratio, more ozone was generated by the wet-plasma reaction. The ozone generation was significantly affected by the input electrical energy, and it needed to be removed before discharged from the process.
        4,000원
        15.
        2014.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Zirconium boride is an artificial or which is rarely found in the nature. ZrB2 is popular in the hard material industry because it has a high melting point, excellent mechanical properties and chemical stability. There are two known methods to synthesize ZrB2. The first involves direct reaction between Zr and B, and the second is by reduction of the metal halogen. However, these two methods are known to be unsuitable for mass production. SHS(Self-propagating High-temperature Synthesis) is an efficient and economic method for synthesizing hard materials because it uses exothermic reactions. In this study, ZrB2 was successfully synthesized by subjecting ZrO2, Mg and B2O3 to SHS. Because of the high combustion temperature and rapid combustion, in conjunction with the stoichiometric ratio of ZrO2, Mg and B2O3; single phase ZrB2 was not synthesized. In order to solve the temperature problem, Mg and NaCl additives were investigated as diluents. From the experiments it was found that both diluents effectively stabilized the reaction and combustion regime. The final product, made under optimum conditions, was single-phase ZrB2 of 0.1-0.9μm particle size.
        3,000원
        16.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Odorous compounds produced from blackwater commonly cause domestic nuisance complaints. In this study, aseries of experiments was conducted to apply an electrolytic oxidation system to abate the odor problems fromblackwater. The electrolytic process removes odorous compounds from the liquid sources using direct and indirectoxidation; therefore, the system performance mainly relies on electrode materials. Four different electrodematerials, SS304, SS316, Ti, Ti/IrO₂, were applied, and the electrolytic oxidation showed that hydrogen sulfideand organic constituents were effectively removed. However, the weights of electrodes, SS304 and SS316, weredecreased by 7.5~8% due to the electrochemical decomposition from the anode surface. In order to improve thedurability and economical feasibility, SS304 was used as the cathode while Ti/IrO₂ was used as the anode. Theelectrode combination with the different materials (Ti/IrO₂:SS304) showed the same odor removal efficiency asthat using the same material (Ti/IrO₂:Ti/IrO₂). Consequentially, the electrolytic reaction to oxidize odorous andorganic constituents in humane manure was strongly affected by the electrode materials, and its combination needsto be carefully selected to achieve better performance.
        4,000원
        17.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        도시지역 합류식 하수배제 설비인 우수받이 및 하수관거, 정화조 등에는 유기성 고형 물이 퇴적되기 쉬우며, 유기성 퇴적물이 부패되는 과정에서 고농도의 황계열 악취물질이 발생한다. 본 연구에서는 전기산화방식을 이용하여 유기성 퇴적물 내에 용존된 악취물질 및 전구물질을 저감시켜, 하수관거에서 기상으로 배출되는 악취 문제를 해결하고자 하였다. 실험실 규모의 밀폐된 회분식 반응기에 하수슬러지(COD 기준 8,000 ~ 28,000 mg·L-1)를 투입하고, 발생되는 악취물질 농도와 악취발생특성을 조사하였다. 여기에 전기산화시스템 을 적용하여 황계열 악취물질과 전체 유기물의 산화 및 분해실험을 진행하였다. 전기산 화 실험을 진행한 결과, 밀폐된 반응기의 기상에서 450 ppm의 고농도로 발생한 황화수 소가 반응 30분 이내에 검출한계 이하까지 제거되었으며, 메틸머켑탄과 디메틸설파이드 는 85% 이상 제거되었다. 투입된 전기에너지당 황계열 악취물질의 제거율은 최대 0.33 mg-S·kJ-1로 나타났다. 또한 1시간의 반응기간 동안 회분식 반응기 내에서 황계열 악취물 질 뿐만 아니라 고농도 퇴적물에 함유된 전체 유기물 농도가 56% 감소하여, 전기산화시 스템이 악취를 유발하는 유기성 전구물질을 동시에 저감하는 효과를 나타내었다. 결과적 으로 최소한의 전기에너지를 이용하여 하수관거 퇴적 유기물에 의한 악취문제를 해결할 수 있을 것으로 기대된다
        4,000원
        18.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 의정부시에 위치한 미군부대(Camp Falling Water) 이전 부지의 활용을 위한 역전근린공원 현상설계 공모전의 우수상 수상작품 내용을 토대로 작성하였다. 계획대상지는 경기도 의정부시 의정부동 142번지 일원에 위치하며, 면적은 29,000㎡이다. 도시 중심부의 공간적 특수성을 고려하여 도시맥락을 흡수하고 소통·연계해야 하는 환경에 대한 공간의 유연성과 자연친화적공원으로써 다양한 행태의 이용가능성 방안을 중점적으로 계획에 반영하였다. 설계의 주안점으로 첫째, 공간의 특수성을 이해하고 지역의 소통을 이룰 수 있는 공간이 되도록 계획하였다. 둘째, 도시 중심부에 위치한 공원이 주변시설들과 오픈스페이스로서의 요구를 수용하는 열린 공간이 되어 감성회복공간이 되도록 계획하였다. 셋째, 특화된 테마를 부여하여 시간과 계절에따른 연계와 유연성을 유도하였으며 친환경적 시설계획으로 이용자들이 다양한 체험을 경험하도록 계획하였다.본 연구는 공간의 한계를 벗어나 주변 환경과 조화를 이루며 지역문화의 소통 및 도심과 녹지의 연계가 가능한 공원조성계획에 기여할 수 있을 것이다.
        4,000원
        20.
        1998.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        알루미늄 전착공정중 도료정제장치에서 발생하는 도료계 폐수(CODMn 1,500~2,000 ppm)를 역삼투압을 이용하여 농축수는 전착조로 보내 재사용하고 반면 투과수는 세정수로 사용할 목적으로 시스템을 설계하여 현장 설치하였다. 역삼투압시스템은 폴리아미드 재질의 나권형 모듈(직경 102 mmtimes 길이 1,016 mm)3개를 직렬로 연결하고 시스템회복율 30%, 운전압력 11.5 kg/cm2, 그리고 실온에서 3일 주기로 발생하는 폐수량 20 m3을 회분식조업으로 처리하였다. 원폐수를 42시간 연속가동하여 5배까지 농축하는 실험기간중 거의 일정한 투과 flux 390 l/m2-hr을 유지하였고 그 투과수질이 CODMn 300 ppm으로 나타났다. 이는 도료정제장치의 잔존 도료성분을 회수하기 위해 사용되는 순수대신 세정수로 사용하기에 적합하였다. 그리고, CODMn 제거율은 83pm5%이었으며, 각 용제성 분별 제거율은 feed 농도의 증가에 따라 감소하였는데 5배 농축시 ethyl cellusolve, butyl cellusolve 그리고 n-butanol은 각각 79, 87 그리고 70%로 나타났다.
        4,000원
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