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        검색결과 131

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the acceptability of locally accepted japonica rice varieties among 53 farmers in Bohol and 38 farmers in Nueva Ecija, who were further classified into adopters and non-adopters of the GUVA japonica rice variety. Snowball sampling was made on farmer adopters/cooperators of a high-quality seed multiplication and dissemination project in the said provinces. The farmer respondents were mostly male whose ages ranged from 30 to 80 years and with farm sizes from 0.5 to 16 hectares. The farmers’ rice variety and usage were assessed by comparing the GUVA japonica rice variety with their commonly planted indica rice variety based on its agronomic characteristics, yield and income potential, and seed purity concerns. The barriers/hesitations to adoption of the GUVA japonica rice variety, namely seed availability, varietal information, and market potential, must be complemented with the suggested improvements on the variety together with factors that convince the farmers for committed use of this variety. Researchers together with partner agencies must put a lot of thought on how to integrate and synchronize these concerns so that the farmers can adopt GUVA japonica rice. Interest check on the usage of GUVA japonica rice variety in rice production as well as suggested improvements were solicited as the basis for continuous R&D pursuits that would eventually promote and adopt the GUVA japonica rice variety from these provinces.
        4,200원
        4.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To determine the acceptability of Grain Utilization Value Added (GUVA) Japonica rice variety developed by the International Rice Research Institute (IRRI) and South Korea’s Rural Development Authority (RDA), home use tests were conducted in n=69 businesses that were using Japonica rice. In general, they were satisfied with the Japonica brands, because they provided them with the particulars needed in their Japanese and Korean dishes. According to them, the value and quality of the Japonica rice justify the price. However, the GUVA Japonica Rice variety’s positive ratings were significantly lower compared to the brands they were used to. This applied to both their overall and attributespecific evaluations. Among the attributes, size, shape, aroma, and stickiness received significantly lower ratings compared to the other Japonica varieties. For them, it was too small, too round, less aromatic, and less sticky which may lead to challenges in preparation consequently affecting the commercial acceptability of the dishes they offer. Even with this experience and perception, they were still willing to consider the GUVA Japonica Rice when it was available in the market. Using the Van Westendorp pricing model, GUVA Japonica yielded a price of PHP 51.00 (1.01 USD) which was competitive. These findings provide recommendations for measures that should be put in place so that value chain players can preserve and maintain quality until the rice reach the business market.
        4,500원
        5.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ultrasonic method is an alternative to the conventional route to produce structured carbon materials, offering the advantages of synthesis in a short period of time under room temperature. The main objective of this work is to synthesize a sulfonated mesoporous carbon catalyst from a phenolic resin composed of phloroglucinol and formaldehyde. The synthesis was performed by the soft-template method in an ultrasonic processor and the product was subsequently carbonized and sulfonated for application in the esterification model reaction. Functionalization with sulfuric acid of MCS5-6 h sample brought about a decrease in porosity but simultaneously resulted in the generation of functional groups of an acidic nature. The MCS5-6 h catalyst with a sulfonic density of 1.6 mmol g− 1, surface area of 402 m2 g− 1 and pore diameter of 10.6 nm maintained in mesoporous even after acid treatment. MCS5-6 h showed excellent activity in the esterification reaction with 95% oleic acid conversion. The recyclability of MCS5-6 h was satisfactory during five reaction cycles. The present work addressed a promising alternative for the synthesis of carbon catalysts using ultrasound irradiation, thus providing an alternative with a lower cost of time and energy for large-scale production.
        4,600원
        6.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetically separable and reusable zinc ferrite/reduced graphene oxide ( ZnFe2O4/rGO) nanocomposite has been prepared by hydrothermal method. The results illustrate that the construction of ZnFe2O4 and rGO occur concurrently in a hydrothermal reaction that initiates the formation of rGO-wrapped ZnFe2O4 nanospheres. The morphological and structural features of the ZnFe2O4/ rGO nanocomposites reveal that the rGO nanosheets anchored to the ZnFe2O4 sphere act as a self-protective clamping layer to avoid the photo corrosion effect under photo irradiations. The nanocomposites express the soft magnetic behavior with high saturation magnetization under annealing temperature at 300 °C, which may attribute to the well-defined crystalline structure and surface defects. In addition, the GZF 300 nanocomposites exhibit the enhanced photocatalytic degradation over Rhodamine B dye which is 3.4, 1.15, and 1.32 times higher than that of ZF, GZF, and GZF 600 over under visible irradiation in 120 min. The GZF 300 nanocomposites demonstrate their ability to degrade RhB efficiently, even after several photocatalysis cycles with high catalyst recovery by its magnetically separable behavior. The high densities of oxygen defects improvise electron transfer from ZnFe2O4 to rGO and delay the recombination process of the nanocomposite, resulting in enhanced visible photocatalytic activity. The strong magnetic properties of rGO wrapped ZnFe2O4 nanocomposite catalysts the easy separation from the suspension system for multiple usages in water treatment.
        4,300원
        7.
        2022.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016–2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 μas < θE < 26 μas, which is consistent with the gap in Einstein timescales near tE ∼ 0.5 days found by Mr´oz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of freefloating planet candidates (FFPs) dNFFP/d logM = (0.4 ± 0.2) (M/38 M⊕)−p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index γ = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of ‘Oumuamua-like objects. In particular, if we assume that ‘Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System’s endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.
        5,800원
        9.
        2021.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Facing the demands of the pandemic and distance learning, English learners require educational technologies that are accessible, engaging, and effective. Meeting these demands requires educational technology developers to consider learners’ sociocultural contexts. Learning theories can be applied to meet individuals’ needs to optimize chances for participation, engagement, and learning gains. This article describes two Internet-based digital technologies that target struggling adult readers who need to improve their comprehension skills: SARA (Study Aid and Reading Assessment) and AutoTutor for Adult Reading Comprehension. The SARA assessment provides a diagnostic profile for individuals’ reading strengths and weaknesses. This profile can be used to guide the selection of reading comprehension lessons in AutoTutor-ARC, a digital technology that both adapts to learners’ performances and engages them in an immersive learning experience using a three-way conversation with computer agents acting as a tutor and a peer to discuss texts. We discuss how these technologies can be integrated into educational settings to improve engagement and learning.
        4,500원
        10.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Even in an era where 8-meter class telescopes are common, small telescopes are considered very valuable research facilities since they are available for rapid follow-up or long term monitoring observations. To maximize the usefulness of small telescopes in Korea, we established the SomangNet, a network of 0.4{1.0 m class optical telescopes operated by Korean institutions, in 2020. Here, we give an overview of the project, describing the current participating telescopes, its scienti c scope and operation mode, and the prospects for future activities. SomangNet currently includes 10 telescopes that are located in Australia, USA, and Chile as well as in Korea. The operation of many of these telescopes currently relies on operators, and we plan to upgrade them for remote or robotic operation. The latest SomangNet science projects include monitoring and follow-up observational studies of galaxies, supernovae, active galactic nuclei, symbiotic stars, solar system objects, neutrino/gravitational-wave sources, and exoplanets.
        4,600원
        11.
        2021.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Reverberation mapping (RM) is an ecient method to investigate the physical sizes of the broad line region (BLR) and dusty torus in an active galactic nucleus (AGN). The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) mission will provide multi-epoch spectroscopic data at optical and near-infrared wavelengths. These data can be used for RM experiments with bright AGNs. We present results of a feasibility test using SPHEREx data in the SPHEREx deep regions for torus RM measurements. We investigate the physical properties of bright AGNs in the SPHEREx deep eld. Based on this information, we compute the eciency of detecting torus time lags in simulated light curves. We demonstrate that, in combination with complementary optical data with a depth of  20 mag in B􀀀band, lags of  750 days for tori can be measured for more than  200 bright AGNs. If high signal-to-noise ratio photometric data with a depth of  21{22 mag are available, RM measurements are possible for up to  900 objects. When complemented by well-designed early optical observations, SPHEREx can provide a unique dataset for studies of the physical properties of dusty tori in bright AGNs.
        4,200원
        12.
        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
        17.
        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
        18.
        2020.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        At q = 1.81 ± 0.20 × 10-5, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio q of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at q = 5-10 ×10-5. The event was observed by Spitzer, yielding a microlens-parallax πE measurement. Combined with a measurement of the Einstein radius θE from finite-source effects during the caustic crossings, these measurements imply masses of the host Mhost = 1.14+0.10-0.12 M⊙ and planet Mplanet = 7.59+0.75-0.69 M⊕, system distance DL = 3.38+0.22-0.26 kpc and projected separation a⊥ = 4.27+0.21-0.23 AU. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.
        5,200원
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