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        검색결과 604

        2.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the feeding behavior and growth performance of 31 Hanwoo steers (10 months old; 278 ± 36.13 kg) within a precision livestock farming system using Roughage Intake Control (RIC) units for real-time data collection. Feeding behavior traits were derived from RIC database data using R software, with subsequent analysis conducted using SAS software. The results indicated that the steers visited the feed stations every 31.12 ± 11.99 minutes, averaging 11 ± 3.37 visits/day. Each feeding session lasted an average of 5.90 ± 1.55 minutes, resulting in a feed intake rate of 77.98 ± 22.53 g/min. Mean daily feed intake was 4.76 ± 1.36 kg, and body weight increased consistently, reaching an average of 412 ± 43.44 kg, with an average daily gain (ADG) of 1.26 ± 0.38 kg. Pearson correlation analysis revealed a strong relationship between daily feed intake and visit duration (r² = 0.621; p < 0.01) and an inverse correlation between daily feed intake and feed intake duration (r² = −0.445; p < 0.05), indicating behavioral adaptation. These findings highlight the importance of monitoring feeding behavior traits concerning growth performance, enhancing our understanding of individual animal behavior and its implications for productivity while emphasizing the role of advanced technologies in optimizing feed utilization in confined livestock systems.
        4,000원
        3.
        2024.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Copper, silver, and gold-reduced graphene oxide nanocomposite (Cu-rGO, Ag-rGO, and Au-rGO) were fabricated via the hydrothermal method, which shows unique physiochemical properties. Environment friendly electromagnetic radiation was employed to synthesize rGO from GO. The nonlinear optical phenomenon of noble metal decorated rGO is predominantly due to excited state absorption, which arises from surface plasmon resonance and increases in defects at the surface due to Cu, Ag, and Au incorporation. It is found that the third-order nonlinear absorption coefficient was in the order of 10− 10 m/W, with notable enhancements in the third-order properties of Au-rGO compared to other nanocomposites and their respective counterparts. Functionalizing rGO induces defect states ( sp3), increasing NLO response. Cu, Ag, and Au exhibit higher Surface-Enhanced Raman Scattering (SERS) activity due to rGO-induced structural modifications. SERS signals are influenced by dominant signals from Au nanorods. The electronic structures for pure and doped rGO were investigated through Density Functional Theory (DFT). The computed partial density of states (PDOS) confirms the enhancement of the state in Au-doped rGO is due to the charge transference from Au to C 2p orbital. The optical absorption spectra and PDOS reveal the possibility of free carrier absorption enhancement in Au which validates experimentally observed higher two-photon absorption (β) value of Au-doped rGO. The tuning of nonlinear optical and SERS behaviour with variation in the noble metal upon rGO provides an easy way to attain tuneable properties which are exceedingly required in both optoelectronics and photonics applications.
        4,800원
        4.
        2024.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the current study, the epoxy material was mixed with 10%, and 30% weight percent carbon material as filler in different thicknesses (1 cm, 1.5 cm, and 2 cm). Transmission electron microscope (TEM) measurements showed the average size of the nano-carbon was 20 nm with a standard deviation of 5 nm. The morphology of samples was examined using scanning electron microscopy (SEM), which showed the flatness of the epoxy surface, and when the content of carbon increases, the connection between the epoxy array and carbon increases. The compression test indicates the effect of nano-size on enhancing the mechanical properties of the studied samples. To survey the shielding properties of the epoxy/carbon composites using gamma-rays emitted from Am-241, Ba-133, Cs-137, Co-60, and Eu-152 sources, which covered a wide range of energies from 0.059 up to 1.408 MeV, the gamma intensity was measured using the NaI (Tl) detector. The linear and mass attenuation coefficients were calculated by obtaining the area under each peak of the energy spectrum observed from Genie 2000 software in the presence and absence of the sample. The experimental results obtained were compared theoretically with XCOM software. The comparison examined the validity of experimental results where the relative division rate ranged between 0.02 and 2%. Also, the measurement of the relative division rate between linear attenuation coefficients of microand nano-composites was found to range from 0.9 to 21% The other shielding parameters are calculated at the same range of energy, such as a half-value layer (HVL), mean free path (MFP), tenth-value layer (TVL), effective atomic number (Zeff), and the buildup factors (EBF and EABF). The data revealed a consistent reduction in the particle size of the shielding material across various weight percentages, resulting in enhanced radiation shielding capabilities. The sample that contains 30% nano-carbon has the lowest values of TVL (29.4 cm) and HVL (8.85 cm); moreover, it has the highest value of the linear attenuation coefficient (LAC), which makes it the best in its ability to attenuate radiation.
        4,500원
        5.
        2023.07 구독 인증기관·개인회원 무료
        Consumer brand engagement has recently drawn attention for researches because of its importance in predicting brand loyalty. Meanwhile, social media is used as digital marketing tools for marketers to attract and engage younger consumers. This study aims to answer the question whether social marketing efforts by fashion brands on major social media platforms have influence on consumer brand engagement in the context of Vietnamese fashion brands. Social marketing efforts include five dimensions of entertainment, interaction, trendiness, customization and word-of-mouth. Although social marketing efforts has been examined in relationship with other important marketing concepts such as brand equity and customer equity (Godey et al., 2016; Kim and Ko, 2012), few studies have investigated its effect on consumer brand engagement, especially in fashion brands. Besides, Vietnam as an emerging market is witnessing considerable changes that social media brings to every field including fashion markets. It is noticeable that more and more fashion brands in Vietnam are trying to expand and advance their marketing strategies on social media to engage consumers. In this study, a self-administered online survey was delivered to Vietnamese consumers, which included 281 valid responses who followed Vietnamese fashion brands on Facebook or Instagram. The empirical results show that social media efforts engage consumers differently on brand engagement dimensions. The key finding indicates that entertainment and word-of-mouth are positively related to brand engagement in affective, cognitive and behavioral dimensions. Interaction is positively related to affective and behavioral brand engagements. Trendiness is positively related to behavioral brand engagement. Finally, customization is positively related to cognitive brand engagement.
        7.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon is a part of all living creatures and it is the chief constructing block for life on this planet carbon occurs in several appearances, mainly as plant biomass, organic matter in soil, as gas CO2 in the air and dissipated in seawater. Soil carbon exhausts when production of carbon increases than carbon contribution. Soil comprises nearly 75% of total carbon existing on land, more than the quantity stockpiled in living animals and plants. So, soil plays a major part in maintaining a stable carbon cycle. Over the previous 150-year-period, the quantity of carbon present in the air has amplified by 30%. Majority of scientists thought that there is a straight relationship amongst amplified levels of CO2 in the air and increasing global warming. One anticipated technique to diminish atmospheric CO2 is to escalate the global packing of carbon in soils. Therefore, there is a necessity to manage soils because soil comprises more inorganic carbon as compared to the atmosphere and more organic carbon as compared to the biosphere. Soil is also thought to be a lively and important constituent in global carbon discharge and potential of sequestration. Carbon sequestration, known commonly as C-storage, can be acquired by different controlling practices, and the size of various management techniques, to enhance C-storage of soil and offer a key basin for atmospheric CO2, can be assessed most persuasively from studies conducted over long time that underwrite exclusive data on soil C accumulation, losses and storage. Sequestration happens when input of carbon enhances as compared to output of carbon. Soil carbon sequestration is the method of relocating CO2 from the air in to the soil with crop leftover and additional organic solids and in a configuration that is not instantly emitted back to the atmosphere. This review focused on beneficial role of carbon sequestrating fertilizers (press mud, boiler ash and compost) in carbon sequestration and soil properties.
        4,600원
        8.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The team has studied the relationship between the ability of the coals to be dissolved in crude anthracene oil and their composition. The coal samples taken from different deposits in Russia and Mongolia were characterized by different stages of metamorphism and tested by the Fourier transform infrared spectroscopy and Carbon-13 nuclear magnetic resonance. The data of a correlation analysis enabled us to find out that an amount of aromatic structures in coal macromolecules provided the main influence on the thermal dissolution of the coals. The middle-rank coals had the highest rates of coal organic matter transfer to liquid products. The data showed that the dissolution process was accompanied by destruction of weak bonds among aliphatic groups. The amount of methylene groups in the aliphatic part of coal macromolecules had a direct impact on conversion of the coal organic matter into soluble products.
        4,000원
        9.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The main objective of the research was to deposit thin films of silver on a graphite carbon paste in a phosphate buffer medium using an electrochemical method. To construct a nitrofurazone detection sensor that is highly sensitive. Different manufacturing parameters, such as electrodeposition potential, pH effect, potential scan rate effect, and number of scan cycles, were examined in this section. The parameters were optimized to improve the deposited silver layers various electrocatalytic characteristics. The Nitrofurazone reduction process is diffusion controlled, as seen by the linear variation of Epc with log(v). The constructed Ag-NPs@CPE electrod has excellent electrical characteristics a large active surface area and low background with extremely high electrical conductivity, according to structural and electrochemical characterizations such as Scanning electron microscopy, X-ray diffraction (XRD) and cyclic voltammetry. The constructed sensor has a very remarkable analytical performance for nitrofurazone molecule identification, with a very low detection limit of about 10– 8 M. The detection of nitrofurazone using our Ag-NPs@CPE sensors in real samples contaminated with the antibiotic nitrofurazone, such as tap water and urine. In the selected sample, the electroanalytical findings reveal a very satisfactory recovery rate of more than 94 percent.
        4,600원
        10.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The bituminous coal was extracted with different industrial solvents like coal tar (CT), heavy cycle oil (HCO) and with their blends to determine the influence of solvent type on the extract yield, composition, thermal behavior, properties such as solubility to toluene and quinoline. The extracts obtained at 380 °C represented pitch-like solid matter with the softening points of 72–127 °C depending on the solvent used. They were characterized using the elemental and group analysis, FTIR spectroscopy, TG-DTG thermogravimetry and liquid chromatography for benzo(a)pyrene concentration. Also, maltene fractions of some extracts were studied by GC–MS. The results showed coal dissolution and the properties of the extracts to differ greatly depending on the solvent used. Coal tar was more favorable solvent for coal dissolution than HCO. Good correlation between the extract aromaticity and the content of the toluene insolubles was observed. The maltene fractions of the extracts obtained with CT and CT blended with HCO consisted mainly of polycyclic aromatics, and that obtained with the HCO contained also large amount of aliphatic compounds. It was found that the amount of the carcinogenic benzo(a) pyrene (BaP) in the toluene soluble fractions of the extracts were different depending on the solvents used for extraction. The remarkable result was that the BaP concentrations in all extracts were much lower than in the solvents used.
        4,000원
        11.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The mechanosynthesis route is a physical top–down strategy to produce different nanomaterials. Here, we report the formation of graphene nanoribbons (GNRs) through this route using carbon bars recovered from discarded alkaline batteries as raw material. The mechanosynthesis time (milling time) is shown to have an influence on different features of the GNRs such as their width and edges features. TEM revealed the presence of GNRs with widths of 15.26, 8.8, and 23.55 nm for the milling times of 6, 12, and 18 h, respectively. Additionally, the carbon bars evolved from poorly shaped GNRs for the shortest milling time (6 h) to well-shaped GNRs of oriented sheets forming for the longest milling time. Besides GNRs, graphene sheets (GNS) of different sizes were also observed. The Raman analysis of the 2D bands identified the GNS signal and confirmed the GNRs nature. ID/IG values of 0.21, 0.32, and 0.40 revealed the degree of disorder for each sample. The in-plane sp2 crystallite sizes ( La) of graphite decreased to 91, 60, and 48 nm with increasing peeling time. The RBLM band at 288 cm− 1 confirmed the formation of the GNRs. Mechanosynthesis is a complex process and the formation of the GNRs is discussed in terms of a mechanical exfoliation, formation of graphene sheets and its fragmentation to reach GNR-like shapes. It is shown that the synthesis of GNRs through the mechanosynthesis route, besides the use of recycled materials, is an alternative for obtaining self-sustaining materials.
        5,400원
        12.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The adsorption of molecular hydrogen on the monolayer graphene sheet under varied temperature and pressure was studied using molecular dynamics simulations (MDS). A novel method for obtaining potential energy distributions (PEDs) of systems was developed to estimate the gravimetric density or weight percentage of hydrogen. The Tersoff and Lennard–Jones (LJ) potentials were used to describe interatomic interactions of carbon–carbon atoms in the graphene sheet and the interactions between graphene and hydrogen molecules, respectively. The results estimated by the use of novel method in conjunction with MDS developed herein were found to be in excellent agreement with the existing experimental results. The effect of pressure and temperature was studied on the adsorption energy and gravimetric density for hydrogen storage. In particular, we focused on hydrogen adsorption on graphene layer considering the respective low temperature and pressure in the range of 77–300 K and 1–10 MPa for gas storage purpose which indicate the combination of optimal extreme conditions. Adsorption isotherms were plotted at 77 K, 100 K, 200 K, and 300 K temperatures and up to 10 MPa pressure. The simulation results indicate that the reduction in temperature and increase in pressure favor the gravimetric density and adsorption energies. At 77 K and 10 MPa, the maximum gravimetric density of 6.71% was observed. Adsorption isotherms were also analyzed using Langmuir, Freundlich, Sips, Toth, and Fritz–Schlunder equations. Error analysis was performed for the determination of isotherm parameters using the sum of the squares of errors (SSE), the hybrid fractional error function (HYBRID), the average relative error (ARE), the Marquardt’s percent standard deviation (MPSD), and the sum of the absolute errors (SAE).
        4,300원
        13.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents a Raman spectroscopy study of the influence of methane flow on the micro-tribological behavior of diamond-like carbon coatings deposited with an industrial plasma-enhanced chemical vapor deposition system. Results have shown a direct relationship between the methane flow and thickness of the coatings. The analysis of the Raman spectra and deposition parameters allowed establishing the influence of H content with the methane flow, the disorder level and estimation of the sp3 fraction on the carbon coatings. The micro-tribology tests showed a strong dependence of the wear resistance and hardness with Raman parameters. The coating deposited at 72-sccm methane flow presented a thickness of 1.7 μm and a sp3 fraction of 0.33. This sp3 fraction gave rise to a hardness of 24 GPa and an excellent wear resistance of 3.3 × 10–6 mm3 N−1 mm−1 for this DLC coating. Wear tests showed a swelling in the wear profiles on this coating, which was associated with the occurrence of a re-hybridization process.
        4,000원
        14.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nickel nanopowders are obtained by the spark discharge method, which is based on the evaporation of the electrode surface under the action of the discharge current, followed by vapor condensation and the formation of nanoparticles. Nickel electrodes with a purity of 99.99% are used to synthesize the nickel nanoparticles in the setup. Nitrogen is used as the carrier gas with a purity of 99.998%. XRD, TEM, and EDX analyses of the nanopowders are performed. Moreover, HRTEM images with measured interplanar spacings are obtained. In the nickel nanopowder samples, a phase of approximately 90 wt% with an expanded crystal lattice of 6.5% on average is found. The results indicate an unusual process of nickel nanoparticle formation when the spark discharge method is employed.
        3,000원
        15.
        2020.12 구독 인증기관 무료, 개인회원 유료
        Bulk carrier ship type is one of the three dominant types of merchant vessels along with container ships and tankers. Recently, in terms of tonnage, bulk carriers constitute about the world's fleet third. The stuff materials indigence such as grains, fertilizers, ores, etc. Since the turn of the millennium, the number has increased considerably. Recently, a growing variance in bulk cargo which has transported by sea, represents now a large part of international commercial exchange shipped by sea. Every year there are huge number tons of cargoes like steel, coals, livestock feed, copper and minerals that are transported by sea in bulk. While most of those shipments are made without accidents, a number of serious injuries have occurred which have resulted not only in the ship's loss, but also in lives loss. In this paper, there is an existing bulk carrier vessel, a computational case study, is made to investigate the different loading conditions effects and bulk cargoes’ types on ship’s stability, in case of damaged conditions, in addition to the effect on the ship’s hull longitudinal strength. A proposed method is suggested to improve the level of safety of the ship past flooding by the usage of air bag (cushion). The candidate vessel consists of two cargo holds. In this paper there are three investigated damage scenarios, the first one is checking the stability in case of damage of cargo hold No.1. The second one is checking the stability in case of damage of cargo hold No.2 and the third scenario is checking the stability in case of flooding of both of the two cargo holds. There’s a modelling software, Auto Ship, is used here to model the vessel, simulate the different scenarios and to run the stability code to check the stability criteria. Finally, after performing the above mentioned three damage scenarios, the result was that the ship will still float in case of scenario one or two but in case of the third scenario, it will sink. So, this study has suggested a way to keep the vessel floating in case of the third scenario until reaching the nearest port without sinking. This proposed method is by using air cushions to open directly in case of existing alarm in the bulk carrier work to fill all the space inside the cargo hold instead of filling with the water.
        4,000원
        18.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A two-level full factorial design 22 with three replications was employed to assess the effect of the incorporation of PSF into the epoxy matrix and the surface treatment of carbon fibers on the work of adhesion (WA) and the interfacial shear strength (IFSS) of carbon fiber–epoxy composites. The IFSS was determined using the microbond (or microdrop) micromechanical test, and the work of adhesion was estimated using two different procedures: (1) using the Owens and Wendt method, and (2) from the Dupre–Young expression using the contact angle θ of a cured epoxy resin on a single carbon fiber and the surface energy of the cured epoxy resin. It was found that the treatment of the carbon fiber with the silane-coupling agent appreciably increases its polar component because of the nitric acid oxidation and the chemisorption of the silane-coupling agent onto the carbon fiber surface. Also, the O=S=O group present in the polysulfone chain resin fairly increases the polar component of the epoxy–PSF blend. The results show that the wetting of the silane-treated carbon fiber by the thermoplastic-modified epoxy resin is better, thus increasing the fiber–matrix adhesion. It was also found that there is a similarity between the trends of both, the IFSS and the WA results. Also, from the ANOVA results it was also seen that both the incorporation of the PSF to the epoxy matrix and the surface treatment of the carbon fibers and their interaction were statistically significant to the IFSS and the WA.
        4,600원
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