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        검색결과 104

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, in order to increase the oxidation resistance of graphite, kaolin and alumina powder with different ratios (26A-74S, 49A-51S, 72A-28S) and slurry method were used to create an aluminosilicate coating on the graphite substrate. In order to reduce the difference in the coefficients of thermal expansion of graphite with aluminosilicate coating, aluminum metaphosphate coating as an interlayer was prepared on the surface of graphite by cathodic electrochemical treatment. The isothermal oxidation test of the samples was carried out in air at a temperature of 1250 °C for 1, 3 and 5 h. The microstructure, chemical composition, and phase components of the coating were, respectively, analyzed by scanning electron microscope equipped with an energy-dispersive spectrometer and X-ray diffraction. The results indicated that, by increasing the withdrawal speed of the samples in slurry method, the amount of changes in the weight of the samples has increased and therefore had a direct effect on oxidation. In addition, it was approved that, at high-temperature oxidation, AlPO4 glass phase forms on aluminum metaphosphate interlayer which retards graphite oxidation. Along with aluminum metaphosphate, aluminosilicate coating also produces a glass phase which fills and seals the voids on the surface which prevents the oxygen to reach the surface of graphite. The created double-layer coating including an interlayer of aluminum metaphosphate + slurry coating prepared with the ratio of 26A-74S as the optimal coating in this research was able to increase the oxidation resistance of graphite by 73% at a temperature of 1250 °C.
        4,600원
        3.
        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
        4.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As a new nanostructure, a graphene is a compound of carbon atoms with a two-dimensional structure that has attracted the attention of many nanoscale researchers due to its novel physical and chemical properties. The presence of all graphene atoms in the surface and its unique electrical properties, as well as the ability to functionalize and combine with another nanomaterial, has introduced graphene as a new and suitable candidate material for gas sensing. Over the years, many researchers have turned their attention to carbon nanomaterial. The unique optical, mechanical, and electronic properties of these nanostructures have led them to use these nanomaterials to develop tiny devices, such as low-consumption sensors. Carbon nanomaterial poses a threat to another nanomaterial in terms of their use in gas sensors. This review article discusses the use of carbon nanoparticles and graphene in gas sensors, examines the nodes in the commercialization pathway of these compounds, and presents the latest achievements. Finally, the perspectives of the challenges and opportunities in the field of sensors based on carbon nanomaterial and graphene are examined.
        6,400원
        6.
        2020.06 구독 인증기관 무료, 개인회원 유료
        Malaysia announced to reduce emission during the 15th Conference of Parties in Copenhagen 2009 by 6th Malaysia Prime Minister YAB Dato’ Sri Mohd Najib Tun Abdul Razak. While, one of the major energy consumption and emission producers are port systems. Therefore, port must minimise emission and pollution, to become green and environmental friendly. Thus, this study looked for the external environmental factors that influencing port become green. The external environmental factors determined using PESTEL analysis; there are political, economic, social, technology, environment, and legal. Next, the priority dominant external environmental for main factors and sub-factors identified using AHP analysis (Analytic Hierarchy Process). Questionnaires used to collect data from expert, and generated from literature review and pilot test. The initial results showed that the first priority main factor is economic, the second priority main factor is technology, and the third priority main factor is environment. At the same time, the results also highlighted that the first priority sub-factor is economic growth, the second priority sub-factor is reduce pollution, and the third priority sub-factor is research and development. The CR (Consistency Ratio) value is less than 0.1 and indicated that the data is considered acceptable. The advance and green technology and system revolution require financial support, and the Environmental Kuznets Curve (EKC) highlighted that people will looking for environmental protection while economic output per capita achieving certain turning point. Thus, the economic growth is significant contributed and influenced Malaysia Port to become green and environmental friendly.
        4,000원
        8.
        2018.10 구독 인증기관·개인회원 무료
        Many herbivorous insects sequester plant defense compounds from their host plants to protect themselves from natural enemies. In plants, these defense compounds are often stored as protoxins separated from their activating enzymes. A well-known example is the glucosinolate-myrosinase defense system in plants of the order Brassicales. When plant tissue is ingested by herbivores, glucosinolates are hydrolyzed by the enzyme myrosinase to form highly reactive isothiocyanates. We previously reported that flea beetles of the genus Phyllotreta selectively sequester high amounts of glucosinolates from their crucifer host plants, and convergently evolved their own myrosinase which enables them to utilize sequestered glucosinolates for their own purposes (Beran et al., 2014). The presence of intact glucosinolates in these beetles suggests that despite tissue damage, ingested glucosinolates are not activated by the plant myrosinase. Rapid and efficient glucosinolate uptake from the gut lumen into gut epithelial cells can prevent hydrolysis and thus might be crucial to overcome this activated plant defense. We use the horseradish flea beetle Phyllotreta armoraciae as a model to study the molecular basis of sequestration in insects. In short-term feeding experiments, we showed that ingested glucosinolates are rapidly sequestered in the foregut. To identify the transporters that mediate glucosinolate import from the foregut lumen into gut epithelial cells, we focused on the MFS transporter family, which is known to transport a wide range of substrates. A phylogenetic analysis of putative MFS transporter sequences identified in P. armoraciae and other beetles revealed several specifically expanded clades in P. armoraciae. Out of 21 candidate genes that were heterologously expressed in Sf9 cells, nine showed glucosinolate transport activity in vitro. Interestingly, most candidate genes were exclusively expressed in the malpighian tubules, and two genes were additionally expressed in the foregut. We currently elucidate the function of these transporters in glucosinolate sequestration in vivo using RNAi. To better understand the function of sequestered glucosinolates, we performed bioassays with P. armoraciae larvae and the generalist predatory ladybird Harmonia axyridis. Upon predator attack, P. armoraciae larvae emitted high amounts of isothiocyanates and ladybird larvae stopped feeding within a few seconds and were highly irritated. However, silencing myrosinase gene expression in P. armoraciae larvae led to increased mortality compared to control larvae in survival assays with ladybird larvae. Our results demonstrate how Phyllotreta use plant defense metabolites to defend themselves against predators.
        9.
        2018.05 KCI 등재 구독 인증기관·개인회원 무료
        Most of the literature on modern-day slavery focuses on women and children as victims of the sex industry. This disproportionate emphasis on sexual exploitation has resulted in conflation of the term trafficking with prostitution, which has led to an understanding of human trafficking issues as separate from other workplace abuses that amount to slavery. By exploring modern-day slavery in the Southeast Asian fishing industry, this paper may fill a research gap within the study of human trafficking as well as sharpen our awareness of slavery practices, not only in the sex industry, but also in workplaces like fishing vessels and seafood processing factories. This paper will argue that the proximity of modern slavery to sexual exploitation and the lack of differentiation between smuggling and trafficking crime has led to the ignorance of contemporary slavery practices in other sectors.
        17.
        2016.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The exploitation of the underwater cultural heritage (UCH) involves various competing interests, which are of private and public, commercial and non-commercial nature. The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage (CPUCH) aims to deal with various issues apropos those competing interests. Its basic concerns include how UCH should be best protected, how in situ preservation should be practised, whether UCH should be commercialized at all or not, and whether salvage should be included in the UCH law. This paper examines these said competing interests and then looks for a balance between them. With an in-depth analysis of the concerned principles and rules, it argues for combination of ‘mutuality interests’ in consonance with the basic legislative scheme of the CPUCH. This approach is meant for the exploitation of UCH both for commercial and noncommercial purposes, which would, in fact, fulfill the expectation of the international community.
        4,800원
        18.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic in ation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.
        3,000원
        19.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have investigated the long term variability of the intensities of the broad-line region emission lines in the UV spectra of Seyfert I galaxy NGC 5548 from 1973-1996. We have obtained the following results: 1) a high level correlation between the intensities of emission lines as well as between intensities of emission lines and continuum uxes was discovered. With increasing wavelength the correlation in both cases becomes weaker, 2) the relationship between the intensity of emission lines and the ux radiation in the continuum can be expressed by a power law function with coefficients of α ≈ 0:8 - 1:1 for different lines. When the difference between the wavelengths of spectral lines and the continuum is increased, the value of the power function decreases, and 3) it was found that the magnitude of the variability of the line intensities are weaker than the range of variability of the continuum uxes. The magnitude of the variability of the line intensities and the continuum uxes increase at longer wavelengths.
        3,000원
        20.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        The results of spectral studies of the CTTS type young star RY Tau with spectrograms of the ultraviolet and the visual ranges are presented. We show the first detection of periodic variability of the emission line intensities in UV and visual ranges with a period of 23 days.
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