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        검색결과 2,696

        241.
        2021.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This research aims to study the simultaneous extraction and transesterification of Chlorella vulgaris (C. vulgaris) using microwave irradiation with methanol as solvent and potassium hydroxide (KOH) as catalyst. The microwave-assisted insitu transesterification of C. vulgaris is assessed at various ratios of biomass-to-methanol, reaction times, and catalyst concentrations during the centrifugation and evaporation process. Gas chromatography-mass spectrometry (GC-MS) analysis is performed to confirm fatty acid methyl ester (FAME) composition. Biodiesel preparation is carried out by simultaneous extraction and transesterification of microalgae from C. vulgaris. The product is then characterized using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR); microalgae are observed using scanning electron microscopy (SEM). The highest amount of FAME is obtained at a biomass-to-methanol ratio of 1:12, reaction time of 40 min, and catalyst concentration of 2 wt%. Biodiesel shows conversion to about 77.64% of methyl ester (methyl myristate, methyl palmitoleate, methyl linoleate, methyl oleate, methyl arachidonate, and methyl 5,8,11,14,17-eicosapentanoate).
        4,000원
        247.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        인공광 이용형 식물공장에서 인공광원의 전력 소모는 작물 생산 비용을 증가시키는 주요한 요인이다. 따라서 인공광원의 광 이용효율을 향상시키는 것은 식물공장의 경제성 확보에 중요한 사안이다. 본 연구의 목적은 다양한 스펙트럼을 갖는 백색 LED와 원적색광을 추가한 다양한 백색 LED에서 재배 된 이고들빼기의 생산성과 광 이용효율을 비교하는 것이다. 파종 후 3주된 이고들빼기 묘는 심지 이용 수경재배 시스템에 정식되었고, 기온 20 ± 0.1°C, 상대습도 60 ± 0.1%, 이산화탄소 938.2 ± 5.8μmol·mol -1 , 광도 PPFD 250.6 ± 0.6μmol·m -2 ·s -1 , 광주기 16시간으로 설정된 인공광 이용형 식물공장에서 5주 재배되었다. 광질 처리조건은 대조구로 식물재배용 3가지 백색 LED(CL 1, CL 2, CL 3), 백색 LED 그룹[Warm W(WW), Neutral W(NW), Neutral W + Red(NWR), Cool W(CW)], 원적색광이 추가된 백색 LED 그룹(WWFR, NWFR, NWRFR, CWFR)이 사용되었다. 백색 LED에 원적색광의 추가는 지상부 생육특성 항목(생체중, 엽장, 엽면적)을 증대시켰고 WWFR 의 지상부 생장이 유의적으로 가장 높았다. 반면에 원적색광의 보광은 엽록소 함량을 감소시켰고 플라보노이드 지수에는 영향을 주지 않았다. 재배기간 동안의 총 소비전력은 CL 1에서 가장 낮았고 WWFR의 총 소비전력이 가장 높았다. WW와 WWFR의 광 이용효율이 높았으며 백색 LED에 원적색광의 추가는 광 이용효율을 3–15% 증대시켰다. 따라서, 백색 LED 에 원적색광의 보광은 작물의 생산성과 광 이용효율을 향상시켜 작물의 생산비용을 감소시킬 수 있었다.
        4,000원
        251.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Physical therapy applied to stroke patients is recognized as a treatment that promotes function recovery, and it is a widely known fact that constant exercise should be performed. However, there are insufficient studies on exercise intensity and exercise time that can minimize side effects and maximize function recovery for exercise therapy. Objectives: To determine the effect of exercise variables on CPK generation during aerobic exercise in stroke patients and to discover how to use appropriate exercise intensity and time when conducting an exercise for function recovery in stroke patients. Design: Quasi-experimental research. Methods: This study classified subjects into three groups (low-intensity exercise group: LIE, moderate-intensity exercise group: MIE and high-intensity exercise group: HIE) according to exercise intensity, and was further classified into two groups (10-minute exercise group: 10MG and 20-minute exercise group: 20MG) according to exercise time variables within each exercise intensity group. After, the change in CPK according to exercise intensity and time was confirmed through hematological analysis. Results: In LIE and MIE, the CPK blood concentrations before and after exercise were increased in 10MG and 20MG, which was not statistically significant (P>.05). In HIE, the CPK blood concentrations before and after exercise were increased in 10MG, and it was statistically significant (P<.05). In HIE, the CPK blood concentrations before and after exercise were increased in 20MG, and it was statistically significant (P<.01). In 10MG and 20MG, the CPK blood concentrations before and after exercises were increased in all intensity group, and there was a statistically significant difference only in HIE. Conclusion: From the results of this study, considering CPK, it will be helpful to recover and improve function if the exercise intensity setting is applied in the type of moderate intensity exercise during physical therapy interventions in stroke patients.
        4,000원
        252.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Machines and facilities are physically or chemically degenerated by continuous usage. The representative type of the degeneration is the wearing of tools, which results in the process mean shift. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore, a preventive maintenance is necessary at some point . The problem of determining the maintenance period (or wear limit) which minimizes the total cost is called the ‘process mean shift problem’. The total cost includes three items: maintenance cost (or adjustment cost), non-conforming cost due to the non-conforming products, and quality loss cost due to the difference between the process target value and the product characteristic value among the conforming products. In this study, we set the production volume as a decreasing function rather than a constant. Also we treat the process variance as a function to the increasing wear rather than a constant. To the quality loss function, we adopted the Cpm+, which is the left and right asymmetric process capability index based on the process target value. These can more reflect the production site. In this study, we presented a more extensive maintenance model compared to previous studies, by integrating the items mentioned above. The objective equation of this model is the total cost per unit wear. The determining variables are the wear limit and the initial process setting position that minimize the objective equation.
        4,000원
        253.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The choice of the culture medium is an important factor for the mass production of mycelia in submerged cultures. The influence of liquid medium on the mycelial dry weight of Paecilomyces tenuipes was investigated in this study. The regression equation is expressed as Y=-1292.94187+17.78612X1+18.92425X2+2.11464X3-0.019375X1X2-0.006276X1X3+0.008177X2X3- 0.070169X1 2-0.292175X2 2-0.008818X3 2, where Y represents the value of the mycelial dry weight (g/L), X1 is the particle size of wood sawdust in liquid medium (mesh), X2 is the concentration of the wood sawdust in liquid medium, and X3 is incubation time (h). The medium was optimized using a response surface methodology, and the optimal medium contained 30 g of wood sawdust (140 mesh), 20 g of glucose, and 10 g/L of peptone. Under these conditions, the mycelial dry weight reached 38.1 g/L (actual value). The culture medium containing wood sawdust is simple and easy to use, highly efficient, and eco-friendly, and its effectiveness in large preparations of P. tenuipes mycelia with low material costs has been demonstrated.
        4,000원
        254.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the winter forage study, Italian ryegrass(IRG) and barley were selected. In 2018, the dry matter yield of IRG was 16,915kg per ha under the Agrivoltaic System; this was a little more than 16,750kg per ha of outdoors. On the contrary, the dry matter yield of barley was slightly less under the Agrivoltaic System than that of outdoors. In 2019, the dry matter yield under the Agrivoltaic System was 12,062kg per ha for IRG and 12,195kg per ha for the barley; this was 5.4% and 11.5% less than that of outdoors, respectively. In the summer forage study, corn and sorghum×sudangrass were selected. In 2019, the dry matter yield of corn under the Agrivoltaic System was 13,133kg per ha which was 17% less than that of outdoors. The dry matter yield of sorghum×sudangrass was 12,450kg per ha, which was 82.5% of that of outdoors. In 2020, the dry matter yield of corn under the Agrivoltaic System was 8,033kg per ha which was 7.9% less than that of outdoors. The dry matter yield of sorghum×sudangrass was 5,651kg per ha, which was 11.4% less than that of outdoors.
        4,000원
        255.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to face common threats from the depletion of fish resources, the decline of production and employment as well as the increase of life risk in East Sea Rim countries, North Korea, South Korea, Japan and Russia due to the Chinese fishing fleets entering East Sea. The recent competition in fishing among fishing vessels and fleets of national origin operating in the East Sea has induced a significant change in the ecological landscape of the fishing fleets cluster while having influenced production and employment in the fishing industries of South Korea and Japan as well as life threat on the fishermen in North Korea. It seems that the population organizational ecological theory can be applied to this change. It can be seen as the isomorphism of the selection process over the exclusive economic zone (EEZ) to avoid the environment in which these North Korean fishing vessels are pushed against the Chinese fleet in the North Korean part of the East Sea. To resolve the fishery disputes or conflict in the common waters in East Sea, first of all, Chinese fishing fleets will be required to put international pressure so as to solve the unfairness of the illegal fishing and overfishing by the International Fishery Organization or the UN violations of the sanctions against North Korea selling fishing rights to China. Although it is not easy for South Korea to cooperate with North Korea in the short term, South Korea will be able to support the fishery infrastructure in North Korea in the mid- to the long-term to prevent the loss of innocent lives for their fishermen and to raise their incomes.
        5,800원
        256.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The emission of particulate matter and volatile organic compounds (VOCs) from a motor vehicle painting booth was quantitatively evaluated. Most particulate matter was emitted during the spraying process, in which the PM10 concentration was 16.5 times higher than that of the drying process. When the paint was being sprayed, the particles with a diameter of 1.0~2.5 μm accounted for 39.4% and particles greater than 2.5 μm in diameter accounted for 30.6% of total particles. On the other hand, small particles less than 0.5 μm in diameter accounted for 52.4% of total particles during the drying process. In contrast to the particulate matter, high concentrations of VOCs were emitted during both spraying and drying processes. Butyl acetate, xylene, toluene, and m-ethyltoluene were the most abundant VOCs emitted from the motor vehicle painting booth. Additionally, xylene, butyl acetate, toluene, and 1,2,3-trimethylbenzene were the dominant ozone precursors. Especially, xylene exhibited the highest ozone production contribution (32.5~44.4%) among 34 species of the ozone precursors. The information obtained in this study can be used to establish a suitable management strategy for air pollutants from motor vehicle painting booths.
        4,200원
        257.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 실내에서 다양한 수온과 염분 조건에서 유독와편모조류 Alexandrium catenella(Group I)의 생장과 함께 마비성패 독의 함량을 조사하였다. A. catenella의 수온과 염분 최적생장은 각각 20~30℃과 20~30 psu였으며, 광온성과 광염성종으로 나타났다. A. catenella는 낮은 수온 구간(10℃와 15℃)에서 독함량과 독성이 높게 나타났으며, 염분에 따라서는 차이가 크지 않았다. 따라서 15℃이하의 수온에서 본 종주와 같은 생리적인 특성을 가진 유독와편모조류가 우점한다면, 이매패류는 빠르게 독화될 가능성이 있다. 향후 A. catenella의 출현에 따른 마비성패독 예찰·예보를 위해 다양한 환경변화에 따른 A. catenella의 다른 종주와 상업적인 이매패류 독화에 대한 연구가 더 필요한 것으로 판단된다.
        4,000원
        258.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        화분매개는 속씨식물 번식에 매우 중요한 역할을 한다. 화분매개 곤충은 식물 다양성과 밀접한 관계를 가지며, 농작물 생산성 향상에 기여 한다. 사과원 내 식물 다양성은 과수와 주변부, 그리고 하부 식생에 의해 결정된다. 본 연구는 사과꽃 개화기에 서양민들레 등 초생이 피복된 사과 원과 초생이 없는 과수원에서 화분매개자의 다양성과 네트워크, 그리고 결실률과 생산된 과실의 크기 차이를 분석하였다. 경북 안동시 길안면 소재 각 5개의 사과원에서 2020년 4월 사과 개화기에 이루어졌다. 사과와 같은 시기 개화하는 초생은 민들레가 우점이었다. 두 사과원 유형에 따른 꿀벌수는 통계적으로 차이가 없었으나, 전체 풍부도 및 검정파리류와 뒤영벌류의 풍부도는 초생 피복 사과원에서 높았다. 민들레 피복 사과원에서 화분매개자 16 그룹과 801개 상호작용이, 초생 제거 사과원에서는 화분매개자 14개 그룹과 589개 식물-화분매개자 상호작용이 확인되었다. 또한, 초생 피복 사과원의 수확기 사과 크기가 더 컸다. 본 연구의 결과는 서양민들레 등 초생 피복은 봄철 화분매개자의 다양도를 증가시킬 수 있고, 수확기 과수의 크기에 긍적적 영향을 줄 수 있으며, 지속 가능한 사과원 경관관리를 위한 초생재배의 중요성을 확인시켜 주었다.
        4,000원
        259.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of supplementing ESP-FM (Erythrobactor sp.), freshwater Chlorella (Chlorella sp.), and baker’s yeast (Saccharomyces cerevisiae) on the nutritional value and mass production of Moina macrocopa, which is used as a live feed for fish fry production, was investigated. Consequently, the effects of feeding the enriched M. macrocopa to the nutritional composition of larval rockfish (Sebastes schlegel) and carp (Cyprinus carpio) was also investigated. Maximum density of M. macrocopa was reached within 15-21 days after inoculation (0.5 to 22 individual/mL), at various temperatures, and either decreased or remained almost constantly thereafter. Protein content and amino acids composition of M. macrocopa were found to be influenced by their respective diets while lipid and ash contents did not considerably change. M. macrocopa fed with baker’s yeast were low in n-3 HUFA content, and those fed on the freshwater chlorella were high in the 18:2n-6 and 18:3n-3 HUFA content, and in cultures treated with ESP-FM were high content in n-3 HUFA. The utilization of M. macrocopa as a substitute fish feed for carp and rockfish showed the enrichment nutritional content.
        4,000원
        260.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구에서는 Perenniporia fraxinea를 사용하여 배지가 카르테노이드 생성 및 균사 성장에 미치는 영향을 분석했습니다. 0.1% 미만의 펩톤을 함유한 맥아추출물은 카르테노이드의 생성을 촉진했으며 0.2% 이상의 펩톤이 그 생산을 억제하는 것으로 나타났다. 맥아추출물이 없으면 Perenniporia fraxinea는 소량의 펩톤 첨가에도 불구하고 카르테노이드를 생산하지 못했다. 아카시재목버섯의 배양을 통하여 생산된 균사체를 원심 분리로 배양액을 분리하여 상층액을 카르테노이드 용액으로 회수가 가능하였다. 균사체 내부에 축적된 카르테노이드는 에탄올을 사용하여 추출하였다. 배양액에서 분리 또는 추출한 카르테노이드 용액은 우수한 DPPH 라디칼 소거 활성을 나타냈다. 본 연구에서 생산된 항산화 카르테노이드는 천연물 유래 물질로 독성 및 부작용이 없으며 항산화 효과가 우수하여 활성산소에 의해 생성된 산화물을 효과적으로 제거할 수 있다.
        4,000원