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        검색결과 11

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mangroves are distributed in intertidal zones of coastal environments or estuarine margins, playing a critical role in the global carbon cycle. However, understanding of the carbon cycle role of mangrove associates in the Republic of Korea is still limited. This research measured soil respiration and leaf gas exchange in three habitats of Hibiscus hamabo (Gimnyeong, Seongsan, and Wimi) and analyzed the impacts on sites and months. Soil respiration was measured once a month from June to October 2022 and leaf gas exchange was measured monthly from June to September 2022. Soil respiration in August (5.7±0.8 μmol CO2 m-2 s-1) was significantly higher than that in other months (p<0.001) and soil respiration increased as air temperature increased (p<0.001). In Seongsan, net photosynthesis in July (9.0±0.9 μmol m-2 s-1) was significantly higher than that in other months (p<0.001). Net photosynthesis increased as stomatal conductance and transpiration rate increased during the entire period (p<0.001). Furthermore, a weak positive linear relationship was observed between soil respiration and net photosynthesis (r2=0.12; p<0.01). The results indicated that soil respiration was influenced not only by air temperature and season but also by net photosynthesis. This study is expected to provide basic information on the carbon dynamics of mangrove associates.
        4,000원
        2.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A one-year-old, female, Maltese dog was presented with head tilting, horizontal nystagmus, and tetraparesis. Blindness was first identified, and magnetic resonance imaging (MRI) scanning revealed diffuse lesion which was hyperintense on T2-weighted image over the cerebellum and brainstem. The immunosuppressive therapy had been administered, but the patient had no improvement. Re-performed MRI revealed the progression of the pre-existed inflammatory lesions. Treatment with prednisolone, leflunomide, cyclosporine, and cytosine arabinoside was initiated. However, neurological signs had been progressive, and the patient was euthanized. The histopathological examination revealed the disseminated granulomatous meningoencephalomyelitis (GME). This GME case suggests the importance of initiation of treatment at the appropriate time.
        4,000원
        3.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fermentation by Rhizopus spp. has been used as a traditional medicine for treating various inflammatory diseases. Allergic asthma is a chronic respiratory disease that is caused by an exaggerated immune response. This study was conducted to ascertain the anti-inflammatory effects of Rhizopus spp. fermentation extract (RU) on a mouse model of ovalbumin (OVA)-induced asthma. The animals were intraperitoneally injected OVA on day 1 and 7, followed by OVA intranasal inhalation on days 14 to 18. The animals were treated daily with RU (100 and 200 mg/kg) by oral gavage from day 18 to day 23. RU significantly decreased eosinophilia and the production of inflammatory cytokines and OVA specific immunoglobulin E in animals with asthma, along with reducing airway inflammation and mucus secretion in lung tissue. Histological changes in the lungs and levels of inflammatory mediators of allergic airway inflammation were evaluated. The regulatory effects of RU on type 2 helper T (Th2) cell activation were investigated. RU administration attenuated asthmatic changes such as inflammatory cell infiltration and mucus production, decreased the levels of Th2-related cytokines, and reduced Th2 cell activation. Administration of RU effectively reduced allergic responses in asthmatic mice, which is associated with regulating Th2 cell activation and differentiation. These results indicate that RU can attenuate the respiratory symptoms of asthma.
        4,000원
        6.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 동남아시아 열대우림의 대표 산림 유형인 MDF, PSF 그리고 HF에서 지상부 바이오매스를 추정하는 것이다. 브루나이에서 MDF, PSF 그리고 HF를 대상으로 각각 3개 지역을 선정하여 20 m×20 m 조사구를 지역마다 9개씩 설치하고 흉고직경 10 cm 이상인 임목의 흉고직경을 측정하였다. 지상부 바이오매스는 측정된 흉고직경과 바이오매스 상대생장식을 활용하여 추정되었다. 지상부 바이오매스는 MDF, PSF 그리고 HF에서 각각 603.3±159.9, 305.9±23.4 그리고 284.3±19.3 Mg ha-1 순으로 나타났다. 산림 유형에 따라 지상부 바이오매스는 유의하게 차이가 있었으며, MDF에서 가장 높게 나타났다. 이는 흉고직경이 70 cm 이상인 거대목이 MDF에서 집중 되어 출현했기 때문이다. 이러한 연구 결과는 산림 유형에 따라 거대목의 출현빈도가 다르며, 나아가 거대목의 출현이 지상부 바이오매스 추정에 영향을 주는 요인 중 하나라는 의미를 가진다.
        4,000원
        7.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 농업기계 산업의 경쟁력 향상을 위한 기초자료를 얻기 위하여 트랙터, 승용이앙기, 콤바인에 대한 국내 공급현황과 농업기계 보유 농가의 향후 교체구입 의향과 사용 만족도를 분석하였다. 1. 최근 10년간 정부 융자지원으로 국내에 공급된 주요 농업기계의 공급대수를 보면 2019년 트랙터 10.7천 대로 2011 년 이후 꾸준히 감소하고 있으며, 승용이앙기와 콤바인은 2019년 각각 3.6천 대, 2.1천 대로 10년전에 비해 23.4, 34.4% 감소하였다. 2. 반면 수입 완제품 농업기계의 수입실적의 경우 2019년 트랙터는 1,433억 원, 승용이앙기는 545억 원, 콤바인은 881억 원으로 2010년에 비해 47~648억 원 증가한 것으로 나타났 으며, 트랙터와 콤바인의 경우 대형기종이 차지하는 비율이 같은 기간동안 각각 32.3, 45.7%p 상승하였다. 3. 한편 농가의 농업기계 교체구입 의향을 분석한 결과 외 국산 농업기계를 보유하고 있는 농가의 구매 충성도가 국산 농업기계 보유 농가에 비해 트랙터 9.4%p, 이앙기 14.3%p 높게 나타났다. 4. 또한 농가에서 농업기계 교체구입 시 제조국을 선택하는데 트랙터의 경우 품질과 고장 관련 만족도가 유의미한 영향을 미쳤으며(p<.001), 승용이앙기와 콤바인의 경우 품질, 고장, 사후 관리 만족도 모두 유의미한 영향을 미치는 것으로 나타났다 (p<.05). 5. 결과적으로 국내 농업기계 공급동향과 농가의 농업기계 교체구입 계획을 고려했을 때 향후 농업기계 교체구입 수요 가운데 외국산의 점유율은 증가한다고 볼 수 있다. 이와 관련하여 국산 농업기계의 경쟁력을 확보하기 위해서는 품질 개선을 위한 관련 기술개발, 사후관리 지원 등의 소비자 인식 전환을 위한 노력이 요구될 것으로 보이며, 이를 위한 정책적인 지원이 필요한 시기로 판단된다.
        4,000원
        8.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This user-centered research aims to empirically evaluate color temperature (K) and illuminance (lx) of residential bathroom lightings to determine the most optimal lighting conditions for productive task performance as well as for satisfying users' emotional needs. Using 3 LED lighting fixtures, 4 types of lighting contexts were investigated; main lighting, task lighting, shower lighting, and bath lighting. Two lightings were installed parallel to the vertical edges of the main bathroom mirror to be used as main and task lighting, while another fixture was installed above the bathtub to be used for shower and bathing. For each lighting context, subjects (N=54) were instructed to perform a few tasks during which time the users were exposed to different lighting conditions with color temperature ranging from 2700 K ~ 6500 K and illuminance ranging from 100 lx ~ 700 lx. Upon completing the given tasks, subjects were asked to evaluate the lighting conditions and their applicability for performing the given tasks. Based on the user evaluations, the most optimal lighting conditions for the different lighting scenarios are as follow: 1) 3500 K ~ 4300 K and 150 lx for main lighting, 2) 3500 K ~ 4300 K and 500 lx ~ 700 lx for task lighting, and 3) 2700 K ~ 3500 K and 100 lx ~ 150 lx for shower/bath lighting. These results can be used to adjust the lighting standards suggested by KS, as well as be utilized by both engineers and designers in designing new types of user-centered bathroom lightings.
        4,000원
        9.
        2018.09 KCI 등재 서비스 종료(열람 제한)
        This study investigated both leaching of heavy metals and ecological toxicity when coal bottom ash (CBA) generated by power plants has been used to reduce both erosion and turbidity of surface runoff at construction sites. The Korean leaching test (KLT) method, sequential extraction method, and acute toxicity test using Daphnia magna were performed to evaluate the environmental impacts and the ecological risks of CBA. According to the results of the KLT method of CBA, trace amounts of Cu were leached at limit of quantitation whereas metal leaching was not monitored for other heavy metals. Through the sequential extraction method of CBA, the relatively high leaching potential was found for As and Pb due to greater fraction of exchangeable (F1) and bound to carbonates (F2), and reasonable probability of leaching under the reducing/anaerobic environment was expected for Cu due to high faction of bound to Fe?Mn oxides (F3). However, significantly low probability of leaching was expected for Cd, Cr, Ni, and Zn with grater fractions of bound to organic matter (F4) and residual (F5). Additionally, total amount of heavy metals in CBA was lower than criteria for soil pollution concerns, and were similar or slightly lower levels than the ‘15 National soil average concentration excluding Cr6+. Finally, acute toxicity test using Daphnia magna display no impact for mobilization and lethality in either the prefiltration or post-filtration experiment, indicating that the ecological toxicity was insignificant with zero values of toxic unit. Consequently, no environmental impacts or ecological toxicity are expected when CBA generated by power plants has been used to reduce both erosion and turbidity of surface runoff at construction sites.
        10.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        In order to promote the resource circulation and upcycling of waste refrigerators, it is necessary to analyze the material flow of recovered valuable resources and low-value residues after they are discharged. This study divided the flow of waste refrigerators into the five steps of discharge, collection, pretreatment, resource recovery, and sale/export/disposal and conducted material flow analysis (MFA) in each step. Waste refrigerators are treated via official (formal sectors, 65.6% of total amount) and unofficial (informal sectors, 34.4% of total amount) channels. Officially, waste refrigerators are collected through free collection by national and local governments, recovery by product producers and distributors, and waste collection·transportation·recycling companies and are recycled at public and private recycling centers. Unofficially, waste refrigerators are collected through junk shops and individual collectors. Waste refrigerators recycled in the formal sectors undergo pretreatment processes such as the disassembly, shredding, and separation and recovery of resources such as scrap irons, plastics, PCB (printed circuit board), cables, glasses, waste refrigerants, urethane, etc. Waste refrigerators recycled in informal sector treated through disassembly of the exterior, the shredding process by the excavators in illegal facilities and recovered waste refrigerants, plastics, glasses, scrap irons, copper, nickel silver, PCB, urethane, etc. MFA results show that in 2015, the amount of waste refrigerators collected from formal sectors reached 121,642 ton/year, the amount of recycling was 107,684 ton/year, and the amount of residues was 13,955 ton/year respectively. Thus, actual recycling rate per a waste refrigerator was estimated 88.15% in 2015. To promote the resource circulation and upcycling of waste refrigerators, it is necessary to find a way to improve the recycling of urethane, which accounts for 10.8% of the total weight of a refrigerator.
        11.
        2016.10 KCI 등재 서비스 종료(열람 제한)
        The flow of products containing valuable metal resources after discharging to waste means that it is necessary to form a plan to improve resource circulation to enhance the circulation of metal resources. In this study, waste resource circulation flow analysis of products containing cobalt and palladium after disposal was performed by classifying five stages: (1) discharge/import, (2) collection/discarding, (3) pretreatment, (4) resource recovery, and (5) product production/export. The mobile phone was one of products which were the most generating cobalt. Discharged cobalt was kept for processing or was produced as pure cobalt, cobalt oxide, or cobalt sulfate, and was used as a raw material for locks, speakers, AlNiCo magnets, tire, batteries, etc. The total amount of cobalt in the waste products was 994 tons and the recycling rate was 53.7%, indicating that 543 ton of cobalt was recycled. Palladium was discharged from waste electrical and electronic products, precious metals, petrochemical catalysts, vehicles catalysts at the end of their life, and medical equipment (dental). The palladium recovered by pre-treatment and resource recovery was recycled as a metal resource or exported. The amount of palladium recycled was 2.412 tons, of which a total of 2.512 or 96% tons is estimated to be recycled. Future research may be necessary to suggest institutional improvements, including the waste resource classification and market expansion for the recycling in the five steps based on the results of this study.