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        검색결과 360

        43.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oil spills into ocean or coastal waters can result in significant damage to the environment via pollution of aquatic ecosystems. Absorbents based on reduced graphene oxide (rGO) foams have the capacity to remove minor or major oil spills. However, conventional chemical synthesis of rGO often uses petrochemical precursors, potentially harmful chemicals, and requires special processing conditions that are expensive to maintain. In this work, an alternative cost-effective and environmentally friendly approach suitable for large-scale production of high-quality rGO directly from used cooking sunflower oil is discussed. Thus, produced flaky graphene structures are effective in absorbing used commercial sunflower oil and engine oil, via monolayer physisorption in the case of used sunflower and engine oils facilitated by van der Waals forces, π–π stacking and hydrophobic interactions, π-cation ( H+) stacking and radical scavenging activities. From adsorption kinetic models, first-order kinetics provides a better fit for used sunflower oil adsorption (R2 = 0.9919) and second-order kinetics provides a better fit for engine oil adsorption (R2 = 0.9823). From intra-particle diffusion model, R2 for USO is 0.9788 and EO is 0.9851, which indicates that both used sunflower and engine oils adsorption processes follow an intra-particle diffusion mechanism. This study confirms that waste-derived rGO could be used for environmental remediation.
        4,800원
        44.
        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
        47.
        2021.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Prognosis of unresectable pancreatic cancer is poor with the rate of surviving more than 5 years is less than 10% despite multi-modalities treatment. The American Society of Clinical Oncology suggested that all patients with metastatic pancreatic cancer should be offered information about clinical trials. Endoscopic ultrasound guided radio frequency ablation has been recently used in patients with advanced stage pancreatic cancer in a few studies. This article has reviewed information from published articles using endoscopic ultrasound guided radio frequency ablation for advanced pancreatic cancer.
        4,000원
        49.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Free-living nematodes feed on bacteria, algae, fungi, dead organisms, and living tissues. They release nutrients for plant use and improve soil structure and water holding capacity. They are usually the most abundant type of nematodes in soil and marine environments. This study has been conducted to survey the distribution and identification of soil nematodes from rhizosphere soil of plant for investigation of indigenous species according to Convention on Biological Diversity. Three species of free-living nematodes belonging to the order of Dorylaimida were found from paddy soil and soybean fields, Miryang, Gyeongsangnam-do and one species was found from soil, Dokdo island, Gyeongsangbuk-do, Korea. Aporcelaimellus obtusicaudatus, Eudorylaimus arcus and Mesodorylaimus spengelii are newly collected from Korea. A. obtusicaudatus can be recognized by its large body, short odontostyle being much thicker than cuticle at the same level, well developed gonads, shape and length of the tail. E. arcus is distinctive because of the wide lateral field, tail form and supplement arrangement. M. spengelii is smaller species with short odontostylet, simple guiding ring. Female tail more or less uniformly attenuated, tip is not swollen, nor curved dorsally.
        4,000원
        53.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report on the one-step synthesis of luminescent carbon nanodots (C-dots) via an electrical discharge between two graphite electrodes submerged into organic solvent (octane). This is a simple approach for the fabrication of C-dots with tunable photoluminescence (PL) that differs from the other preparation methods, as no post-passivation step is required. The synthesized carbon nanoparticles are of spherical shape and their size is distributed in the range of 2–5 nm and exhibit luminescence sensitive to excitation wavelength.
        4,000원
        54.
        2020.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the discovery of a giant exoplanet in the microlensing event OGLE-2017-BLG-1049, with a planet―host star mass ratio of q = 9.53 ± 0.39 × 10-3 and a caustic crossing feature in Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of θE = 0.52 ± 0.11 mas. However, the microlens parallax is not measured because the time scale of the event, tE ≃ 29 days, is too short. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. We fi nd that the lens system has a star with mass Mh = 0.55+0.36 -0.29 M⊙ hosting a giant planet with Mp = 5.53+3.62 -2.87 MJup, at a distance of DL = 5.67+1.11 -1.52 kpc. The projected star{planet separation is aㅗ = 3.92+1.10 -1.32 au. This means that the planet is located beyond the snow line of the host. The relative lens{source proper motion is μrel ~ 7 mas yr-1, thus the lens and source will be separated from each other within 10 years. After this, it will be possible to measure the flux of the host star with 30 meter class telescopes and to determine its mass.
        4,000원
        55.
        2020.12 구독 인증기관 무료, 개인회원 유료
        Systematic literature reviews (SLR) are very important to track the extent to which studies related to the formulation of Halal Catering on board have been previously studied by previous scholars. Therefore, the SLR study requires a clear and detailed understanding concerning the study direction for each selected article by analyzing the scope of the study and its dimensions as the main emphasis whether it has been discussed by any previous scholar or otherwise. Through the basis of the analysis of literature reviews will enable the specific detection of the title of the study. Even SLR analysis is also able to compare in terms of the year the article was published by comparing the differences in scope and dimensions of each article by selected scholars referred to 16 scholars from the year 2012 until 2017. Regards to methodology, SLR emphasised into five stages such as i) Time Frame, ii) Selection of a database, iii) Journal selection, iv) Article selection and v) Literature review analysis. Analysis, discussion, and findings will be focusing on the scope, dimensions, and years of studies by using figures, tables as facilitators of analysis and findings. Hence, the role of Halal institutions will be able to assess its ability to form halal rules with the involvement of stakeholders and the scope that has been affected in detail.
        4,000원
        56.
        2020.11 구독 인증기관 무료, 개인회원 유료
        This paper suggests a theoretical conceptual framework focusing on the individuals' affective process of country image evaluation, through the examination of the positive relationship among the country's responsiveness to individuals A-R-C needs with, and the country's emotional attachment. The main contribution of this paper is that it is operating as countries’ “BIAS map” for their future actions and policy strategies for their individuals’ well-being safeguard.
        4,500원
        57.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국 땅나리와 섬말나리의 수요는 최근까지도 늘어났지만 종자 상태에서 개화에 이르기까지 확률은 낮은 편으로 자생지에서의 개체수는 해마다 감소하였다. 본 연구는 땅나리(Lilium callosum Siebold & Zucc.)와 섬말나리(L. hansonii Leichtlin ex D.D.T. Moore)의 대량증식을 도모하기 위하여 종자 발아에 유리한 주·야간 온도 조건과 적합한 GA3 농도를 알아보는 것을 목적으로 수행되었다. 땅나리 종자는 2017년 10월 24일 강원도 춘천히 둔산면 원창리(37°47’10.00”N, 127°44’31.00”E), 섬말나리 종자는 2017년 10월 2일 울릉도 울릉군 북면 나리 (37°31’27.06”N, 130°52’25.08”E)에서 채종하였다. 땅나리와 섬 말나리 종자들을 주·야간 15/5, 20/10, 25/15, 20/20°C의 환경 조절상에서 처리구 당 30립씩 3반복으로 치상하여 온도 처리 실험을 진행한 후, 발아율 결과가 가장 우세했던 온도 조건의 환경조절상에서 섬말나리 GA3 처리 실험을 추가로 진행하였다. 온도 처리 실험결과 땅나리는 20/20°C의 온도 조건에서 발아율이 95.0%로 가장 높았으며 평균발아소요일수 또한 10.1일로 가장 낮았다. 섬말나리는 20/20°C의 온도 조건에서 발아율이 78.8%로 가장 높았으며 평균발아소요일수 또한 40.1일로 가장 낮았다. 이를 토대로 20/20°C에서 실시한 섬말나리 GA3 처리 실험은 증류수를 대조구로하여 200, 400, 800mg・L-1의 농도로 상온에서 24시간 침지한 후 처리구 당 20립씩 3반복으로 치상하였다. 그 결과 대조구에서 81.6%로 가장 높은 발아율을 나타냈으며 평균발아소요일수는 200mg・L-1처리구에서 37.1일로 가장 낮았다. 이러한 실험 결과를 바탕으로 땅나리와 섬말나리의 주·야간 발아 최적 온도는 20/20°C이며 GA3 24 시간 처리는 섬말나리 종자 발아에 효과가 없는 것으로 판단 되었다.
        4,000원
        58.
        2020.06 구독 인증기관 무료, 개인회원 유료
        The formulation of Halal and Catering Regulation on board is a new draft proposal in shipping industry in the nation to ensure Muslim seafarers will be protected under social welfare. Currently, there are no regulations in place regarding the formulation of provision of Halal and Catering which have been enforced by several authorities at different sector in the nation. However, Halal JAKIM is an expert and focal point with the right to issue Halal certification not only in this nation but globally. The main objective of the study was to form a Halal committee on board for the co-ordination of responsibilities between the agencies, and the second objective was to establish the Halal and Catering Regulations on the merchant vessel for the Malaysian flag. The problem is that seafarers feel insecure about the preparation of halal food and no regulations have been issued to date. In fact, this study requires Qualitative methods because several actions related to the Halal-Toyibban Policy and food preparation rules should be obtained through closed-ended interviews with Halal regulatory experts, ship-owners, and selected stakeholders. Therefore, the analytical process will refer to the use of transmitted transitions from oral to text through the coding system in facilitate the content analysis process; and further to the level of discussion and findings. Ship-owners should ratify the Halal and Catering Regulations once they are enacted. The results of this study are expected to formulate the framework for the Halal and Catering Committee involving the agency by reference to interdependent theory. The second finding was to formulate a draft of the Halal and Catering Regulations on the Malaysian merchant vessel by reference to the application of benchmarking theory. Finally, this study will benefit the Muslim seafarer with the cooperation of the ship-owner and the relevant government agencies.
        4,600원
        59.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The possibility of orange pulp utilization for nanoporous carbons production was investigated. Moreover, processing the obtained materials as limonene oxidation catalysts was studied as well. Limonene was separated from orange pulp obtained from fragmented orange peels—the waste from industrial fruits processing—by means of simple distillation. After the separation of limonene from the biomass, the dried orange pulp was converted to three types of nanoporous carbon catalysts: without activating agent, with NaOH, and with KOH. The catalysts were characterized by XRD, SEM, EDX, AFM, and sorption of N2 methods. The activities of the obtained catalysts were tested in the oxidation of limonene to perillyl alcohol (the main product), carveol, carvone, and 1,2-epoxylimonene and its diol. In the oxidation processes, hydrogen peroxide was used as the oxidizing agent. This work has shown for the first time that nanoporous carbons obtained from orange pulp waste, after separation of limonene, are active catalysts for limonene oxidation to industrially important value-added products.
        4,000원
        60.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 최소한으로 가공된 안전한 식품에 대한 소비자의 수요가 기하급수적으로 증가하고 있다. 이러한 이유로 많은 식품가공 업체에서는 식품안전을 강화하고 유통기한을 연장하기 위한 최소한의 가공공정 중 허들기술(hurdle technology)을 적용하고 있다. 한편, 연구에 따르면 식품에 함유된 병원균을 비활성화하기 위한 공정 및 방법들은 식중독세균들의 스트레스 적응 메커니즘을 촉발시켜 심지어 후속 치료로부터 교차 보호를 준다. 또한, 항생 제와 제초제 사용과 같은 일상적인 농장 관행은 항생제 내성을 가진 병원균의 생성을 초래할 수 있다. 이러한 항생제 내성 박테리아는 식품 처리과정과 관련된 스트레스에 내성을 가질 수 있고 가공 식품에서 생존 할 수 있는 가능성을 높일 수 있다. 이 리뷰에서는 식품 가공과 관련된 스트레스와 항생제 내성의 상관관계에 대해 논의한다. 또한, 항균성 화합물 및 기타 식품 처리 관련 스트레스에 대한 교차 보호 수단으로서 시그마 인자 (sigma factors), SOS 반응 경로(SOS response pathways) 및 유출 펌프(efflux pumps)의 사용과 같은 분자유전학적 기작에 대해서도 논의한다.
        4,000원
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