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        검색결과 494

        1.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study investigates the impact of freeze–thaw deterioration on the electrical properties and electric-heating capabilities of cement mortar incorporating with carbon nanotubes (CNT) and carbon fibers (CF). Mortar samples, containing 0.5 wt.% CNT and 0.1 wt.% CF relative to the mass of cement, were prepared and subjected to freeze–thaw tests for up to 300 cycles. The electrical properties and electric-heating capability were evaluated every 30 freeze–thaw cycles, and the physicochemical characteristics of the samples were analyzed using X-ray diffraction and mercury intrusion porosimetry. The results indicate a decline in both electrical conductivity and heat-generation capability as the freeze–thaw cycles progress. Furthermore, changes in the pore structure of the mortar samples during the freeze–thaw cycles contributed to damage in the conductive network formed by CNT and CF, resulting in decreased electrical conductivity and heat-generation capabilities of the mortar samples.
        4,200원
        2.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electrochemical oxidation and reduction reactions are fundamental in various conversion and energy storage devices. Functional materials derived from MOFs have been considered promising as electrical catalysts for ORR, HER, and OER, which can be used in Zinc-air batteries and water electrolysis. Herein, we designed a novel approach to fabricating the ultrafine Co9S8 embedded nitrogen-doped hollow carbon nanocages ( Co9S8@N-HC). The method involved a process of sulfidation of cobalt-based metal–organic frameworks (ZIF67) and then coating them with polypyrrole (PPy). PPy has notable properties such as high electrical conductivity and abundant nitrogen content, rendering it highly promising for catalytic applications. The Co9S8@ N-HC catalyst was successfully synthesized via the carbonization of CoSx@ PPy. Remarkably, the Co9S8@ N-HC catalyst demonstrated exceptional electrocatalytic activity, requiring only low overpotentials of 285 mV and 201 mV at 10 mA cm‒ 2 for OER and HER, respectively, and exhibited high activity for ORR, with an onset potential ( Eonset) of 0.923 V and half-wave potential ( E1/2) of 0.879 V in alkaline media. The electrocatalytic efficiency displayed by Co9S8@ N-HC opens a new line of research on the synergistic effect of MOF-PPy materials on energy storage and conversion.
        4,200원
        3.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Balloon-borne Investigation of Temperature and Speed of Electrons in the corona (BITSE) mission, performed by KASI and NASA, used a high-altitude scientific balloon. The purpose of BITSE was to investigate the scientific feasibility of electron temperature and velocity measurements in the solar corona using wavelength-dependent polarization brightness differences. KASI was responsible for developing the command and data handling (C&DH) system, including the main electronics unit and flight software (FSW). Here, we introduce the development of C&DH system of BITSE and describe the ground integration and test and flight operations. The main electronics unit was built using an industrial-grade modular system in customized enclosures that withstood the operating environment. The FSW was developed using the core Flight System (cFS), an open-source software framework developed by NASA and used in several successful space missions. BITSE was launched at Fort Sumner, New Mexico, USA, on September 18, 2019. It observed the solar corona for approximately 4 hours at an altitude of approximately 40 km and collected 16,000 solar corona images. This study could provide guidelines for developing the C&DH system for future balloon missions.
        4,600원
        5.
        2024.04 구독 인증기관·개인회원 무료
        Calonecrinae represent a unique but small subfamily of Nitidulidae that is endemic to South Asia. Their habitats, the South Asian lowland forests, are under the imminent threat of degradation, posing a risk of rapid extinction for these species in their specific locales. Despite the looming threat to their existence, our understanding of this enigmatic group remains limited. We conducted an examination of museum and newly collected specimens, alongside a review of the literature, leading to the discovery of a new species, Calonecrus mindanaoensis, from Mindanao, Philippines. For the first time, the morphology of all immature stages of the Calonecrinae was described, with detailed photographs including SEM images. Additionally, their natural history was uncovered for the first time, revealing that all life stages are uniquely adapted to spending their entire life cycle within sticky resin. We re-evaluated the phylogenetic placement of the Calonecrinae by constructing a phylogenetic tree based on the mitochondrial genome. Calonecrinae are positioned within the Epuraeinae clade and show significant affinity with the genus Trimenus. Consequently, this study proposes reclassifying Calonecrinae as Calonecrini stat nov, an extremely modified tribe within the Epuraeinae.
        6.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since rice is the main food in Korea, there are no regulations on corn milling yet. Corn is known as one of the world's top three food crops along with wheat and rice, and it is known that 3.5 billion people worldwide use corn for food. In addition, corn mills are not developed or sold in Korea, but the use of corn mills is increasing significantly in many countries in Southeast Asia. In the Philippines, as Korea's rice mill import increases, Korea's KAMICO (Korea Agricultural Machinery Industry Cooperative) and domestic company A agreed to develop a corn mill jointly with PHilMech, an organization affiliated with the Philippine Ministry of Agriculture. However, research on corn milling was very insignificant, so the development was carried out based on the technology of Korea's rice mill. Rice milling is performed by peeling off the skin of rice and producing brown or white rice, so it is carried out by removing the skin and cutting the skin. On the other hand, in the corn mill, the skin of the corn is peeled, pulverized and selected to produce main products suitable for edible use. Therefore, in order to develop a corn mill, processes such as peeling, transfer, grinding, sorting, and by-product separation are required, and suitable parts must be developed. In addition, the performance must be gradually improved through experiments in which corn is repeatedly milled. The Philippines produces 7.98 million tons/year of corn, which is about 100 times that of Korea, and is mostly consumed as a staple food. This is about 10% of the total crop production in the Philippines. In addition, the main cultivation complexes of corn are the mountainous regions of Tarlac or Pangasinan, and the produced corn is 72.4% of the so-called yellow corn called Arabel and Sarangani, and the remaining 27.6% are known as white corn. In this study, it was intended to produce grains of 2.5 mm or less suitable for food for yellow corn and to develop a corn mill for 200 kg per hour. Detailed conditions for development are stipulated as more than 55% of the main product recovery rate, more than 31% of the by-product recovery rate, less than 5% of the raw material loss rate, and more than 80% of the embryo dislocation rate. In this study, to achieve this, the overall process of the corn mill was developed, and the optimal conditions for the corn mill were obtained through the development of parts and empirical tests to improve performance. In addition, it was intended to achieve the development goal by evaluating and analyzing the performance of each part so that it did not conflict.
        4,800원
        7.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bangladeshi medicinal plants (BMP) have a history of traditional use in treating chronic inflammatory diseases, but a BMP bark’s antioxidant and anti-inflammatory effects remain largely unexplored. This study assessed methanolic extracts’ antioxidant and anti-inflammatory properties from the bark of 15 medicinal plant species native to Bangladesh. The methanol extracts of BMP bark were evaluated for their total antioxidant activity and ability to counteract inflammation induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Among the 15 bark extracts from BMP, Albizia odoratissima (A. odoratissima), Engelhardia spicata (E. spicata), and Shorea robusta (S. robusta) showed the highest total phenolic contents and total antioxidant capacity by effectively scavenging free radicals. In particular, these three bark extracts significantly reduced the mRNA expression of LPS-induced inflammatory cytokines and enzymes inducible by inflammation in macrophages. Also, the mRNA expression of NADPH oxidase 2 was significantly suppressed by the three bark extracts in LPS-induced RAW 264.7 macrophages. These results suggest that out of the 15 bark extracts obtained from medicinal plants in Bangladesh, the extracts from A. odoratissima, E. spicata, and S. robusta exhibit substantial total antioxidant capacity by efficiently scavenging free radicals and also inhibit LPS-induced inflammation in macrophages.
        4,000원
        8.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent times, there has been a significant demand for supercapacitors in energy storage applications due to their rapid charging– discharging capabilities, high power density, and excellent stability. Nevertheless, the synthesis of electrode materials with a substantial surface area, exceptionally high porosity, and superior electrochemical performance is still challenging. Activated carbons with a distinctive porous structure and exceptional electrochemical properties emerged as promising electrode materials for supercapacitors. In this study, we used a porous activated carbon (PAC) derived from petroleum coke followed by KOH activation as an efficient anodic electrode material. The ultra-high Brunauer–Emmett–Teller surface area of 2105.6 m2 g− 1 with stacked layers of carbon atoms arranged in a two-dimensional hexagonal structure makes the PAC an efficient candidate for a supercapacitor electrode. The PAC delivers a specific capacitance of 470 F g− 1 at a current density of 0.5 A g− 1 over a potential window of 0 to −1 V. The excellent cycling stability in a three-electrode setup with a capacitance retention of ⁓98% even at a high current density of 10 A g− 1 makes the PAC a potential anodic electrode material for high-performance supercapacitor applications.
        4,000원
        9.
        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
        10.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to reset the maximum residue limit (MRL) for didecyldimethylammonium chloride (DDAC) in broiler chickens. The disinfectant containing DDAC (10%, w/w) was diluted 160 times and evenly sprayed on the bodies of twenty-four broiler chickens at a rate of 15 mL per day per bird for 7 days. After the disinfectant treatment, tissue samples were collected from six broiler chickens at 0.25, 1, 3 and 5 days, respectively. Residual DDAC concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 2.0~10.0 μg/kg), recoveries (86.9~118.6%), and coefficient of variations (<19.98%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In all tissues except for liver, DDAC was detected more than LOQ at 5 days after the disinfectant treatment. In liver tissues, DDAC was detected more than LOQ at 3 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal period of DDAC in poultry tissues was established to 26 days. In conclusion, the developed analytical method is sensitive and reliable for detecting DDAC in poultry tissues. When DDAC disinfectant is sprayed on a poultry house in the presence of broiler chickens, it is necessary to keep the disinfectant from contacting the body of the livestock.
        4,000원
        11.
        2023.10 구독 인증기관·개인회원 무료
        Ricania sublimata are insects invaded in South Korea from China 2011. It has been happening continuously since invaded and It is established and continues to increase and occur in various crops such as persimmons, peaches, and apples. The nymphs and adults of R. sublimata causes damage by sucking the stems and leaves of trees. Yellow, blue, and white sticky traps (25x15cm) were installed in the 1000m2 Omija(Schizandra Chinesis Baillon) orchard september 2020 and the trap captures by color was investigated. In addition, yellow sticky traps were installed at heights of 1m, 1.7m, and 2m, and the trap captures according to the height was investigated. As a result of attraction according to the color of the sticky trap, yellow trap was the most attractive, blue and white traps had little attraction. And result of capture according to the yellow sticky trap height the most were caught at 1.7m height, followed by 1m and 2m in that order. Therefore, it is considered reasonable to investigate the density and monitoring of R. sublimata using yellow sticky trap.
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