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        검색결과 421

        47.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Supercross-linked polymers are widely used as carbon precursor materials due to their abundant carbon sources and low cost. In this paper, a supercross-linked polymer was prepared by the solvothermal method. The supercross-linked polymer as a precursor and the PPyC-800-A was synthesized by activating this with KOH. The microstructure, structure, and electrochemical performances of porous carbon PPyC-800-A were studied at different of temperature and carbon alkali ratio. According to the results, the porous carbon PPyC-800-1:2 is mainly composed of a stack of spherical particles with a high surface area of 1427.03 m2 g− 1, an average pore diameter of 2.32 nm, and a high specific capacitance of 217.7 F g− 1 at a current density of 1.0 A g− 1 in a 6 M KOH electrolyte. It’s retention rate is 97.58% after 5000 constant current charges and discharges. With a specific capacitance decay rate of 21.91 percent, an energy density of 11.96 Wh kg− 1, and a power density of 500.0 W kg− 1, the current density rises from 1.0 A g− 1 to 10.0 A g− 1, exhibiting remarkable electrochemical properties, cycling stability, and energy production performance This study contributes experimental ideas to the field of supercrosslinked polymer-derived carbon materials and energy storage.
        4,300원
        48.
        2023.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Spin-off pyroprocessing technology and inert anode materials to replace the conventional carbon-based smelting process for critical materials were introduced. Efforts to select inert anode materials through numerical analysis and selected experimental results were devised for the high-throughput reduction of oxide feedstocks. The electrochemical properties of the inert anode material were evaluated, and stable electrolysis behavior and CaCu generation were observed during molten salt recycling. Thereafter, CuTi was prepared by reacting rutile (TiO2) with CaCu in a Ti crucible. The formation of CuTi was confirmed when the concentration of CaO in the molten salt was controlled at 7.5mol%. A laboratory-scale electrorefining study was conducted using CuTi(Zr, Hf) alloys as the anodes, with a Ti electrodeposit conforming to the ASTM B299 standard recovered using a pilot-scale electrorefining device.
        4,600원
        49.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon nanotube fiber is a promising material in electrical and electronic applications, such as, wires, cables, batteries, and supercapacitors. But the problem of joining carbon nanotube fiber is a main obstacle for its practical development. Since the traditional joining methods are unsuitable because of low efficiency or damage to the fiber structure, new methods are urgently required. In this study, the joining between carbon nanotube fiber was realized by deposited nickel–copper doublelayer metal via a meniscus-confined localized electrochemical deposition process. The microstructures of the double-layer metal joints under different deposition voltages were observed and studied. It turned out that a complete and defect-free joint could be fabricated under a suitable voltage of 5.25 V. The images of the joint cross section and interface between deposited metal and fiber indicated that the fiber structure remained unaffected by the deposited metal, and the introduction of nickel improved interface bonding of double-layer metal joint with fiber than copper joint. The electrical and mechanical properties of the joined fibers under different deposition voltages were studied. The results show that the introduction of nickel significantly improved the electrical and mechanical properties of the joined fiber. Under a suitable deposition voltage, the resistance of the joined fiber was 37.7% of the original fiber, and the bearing capacity of the joined fiber was no less than the original fiber. Under optimized condition, the fracture mode of the joined fibers was plastic fiber fracture.
        4,500원
        50.
        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
        51.
        2022.12 구독 인증기관 무료, 개인회원 유료
        This research purposely conducts to identify Malaysian role in port bilateral diplomacy in ASEAN. Malaysia known as role leader in ASEAN and commit with excellence, drive the country among ASEAN since 1969. The research included Malaysia role within maritime working group where this forum or organization discuss and negotiate any issue related maritime sector in ASEAN. The research also highlights in Port Enhancement and Malaysia Port Strategic whereas Port Development in Malaysia that contribute to Port Bilateral, Port Alliance and Port in ASEAN. The objective includes i) to identify the issues and challenges in bilateral diplomacy in port shipping, ii) to identify Malaysian marine department role toward integrating ASEAN Maritime Working Group, iii) to find out Malaysian initiative for enhancement Malaysian Port Development through ASEAN port alliances, iv) to formulate Malaysia Port Strategic Plan toward the development of national port ASEAN port Alliances. For the literature review in this research is refer to five keywords which is Port Alliances, maritime working group, Malaysia contribution, Malaysia Port Development and Port Strategic Plan. This research is using qualitative method that refer to previous research, article, and journal. The collecting data consist of text transcribe form interview session into verbal and text written. There are selected organization such as Ministry of Transport and Port Authority. The interview process through online using Webex. The coding process take afterward for analysis and conclusion data. The theory formulation of relation diplomacy for this research is propose the objective to formulate Malaysia port strategic plan toward the development of national port ASEAN. Finally, the finding of this research that Malaysia plays significant role in port operation through ASEAN regional. The ministry of Transport plays as policy maker and drive the actor form Malaysia Marine Department and Port Authority in operation and regulatory. The recommendation is to increase the effectiveness of communication and enhance the efficiency of relation toward port bilateral.
        5,200원
        52.
        2022.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This explorative paper investigates the application of human rights to civil law cases in Indonesia. Human rights are often placed within the realm of public law. Yet, fundamental rights and freedoms also apply to private law cases. The human rights literature, however, does not exist in Indonesian private law. This article explores how human rights are applied in Indonesian civil law cases with reference to the models of human rights application developed by Aharon Barak and Olha Cherednychenko. We found that in Indonesia, judges apply human rights law to civil law cases indirectly, yet this application is inconsistent. The Supreme Court has attempted to increase legal unity by making case law (yurisprudensi) more accessible and by issuing internal regulations that must serve as guidelines for judges-including the application of fundamental rights in civil law cases. Case law and guidelines, however, lack thorough legal reasoning and are, therefore, difficult to apply to complex cases.
        5,800원
        53.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Few studies have been performed on ZrB2- graphite platelet composite made by spark plasma sintering (SPS) technique. In this research, the influence of adding graphite platelets (Gp) with and without SiC on the fracture toughness of ZrB2 ceramic was studied. The ZrB2- 10Gp, ZrB2- 15Gp, ZrB2- 30SiC-10Gp, and ZrB2- 30SiC-15Gp specimens were sintered by the SPS method at the temperature of 1850 °C for 8 min. The fracture toughness and work of fracture (WOF) were evaluated using the Single-Edge Notched Beam (SENB) technique. It was found that the fracture toughness and WOF were improved by the alone and combined addition of Gp and SiC to the monolithic ZrB2. The maximum fracture toughness of 4.8 ± 0.1 MPa m1/ 2 was obtained for the ZrB2- 15Gp specimen. It seems that adding Gp alone was more effective in enhancing the fracture toughness of ZrB2 than the combined addition of Gp and SiC. While the addition of Gp and SiC simultaneously modified the densification behavior to reach full-densified samples.
        4,000원
        54.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is an ever growing interest in the development of biochar from a large variety of agrowastes. Herein, the main objective is the conversion of pomegranate peel powder biochar and its post-functionalization by phosphoric acid treatment, followed by arylation organic reaction. The latter was conducted using in situ-generated diazonium salts of 4-aminobenzoic acid ( H2N-C6H4-COOH), sulfanilic acid ( H2N-C6H4-SO3H) and Azure A dye. The effect of diazonium nature and concentration on the arylation process was monitored using thermal gravimetric analysis (TGA) and Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). SEM pictures showed micrometer-sized biochar particles with tubular structure having about 10–20 μm-wide channels. SEM studies have shown that arylation did not affect the morphology upon arylation. The porous structure did not collapse and withstood the arylation organic reaction in acid medium did not collapse upon arylation. TGA and Raman indicated gradual changes in the arylation of biochar at initial concentrations 10– 5, 10– 4 and 10– 3 mol L− 1 of 4-aminobenzoic acid. The detailed Raman spectra peak fittings indicate that the D/G peak intensity ratio leveled off at 3.35 for 4-aminobenzoic acid initial concentration of 10– 4 mol L− 1, and no more change was observed, even at higher aryl group mass loading. This is in line with formation of oligoaryl grafts rather than the grafting of new aryl groups directly to the biochar surface. Interestingly, Azure A diazonium salt induced much lower extent of surface modification, likely due to steric hindrance. To the very best of our knowledge, this is the first report on diazonium modification of agrowaste-derived biochar and opens new avenues for arylated biochar and its applications.
        4,200원
        55.
        2022.10 구독 인증기관·개인회원 무료
        Niobium (Nb) is present in Ni-based alloys and stainless steels used in nuclear reactors as structural materials. Nb-93 is a naturally occurring and stable isotope of niobium and Nb-94 (half-life = 20,000 years) is produced by neutron activation of Nb-93. Nb-94 can be present in waste streams from dismantling of nuclear power plants and treatment of the primary coolant circuit. Hence, the radioactive wastes containing active Nb-94 are disposed of in the repositories for low- and intermediate-level waste (LILW). Nb predominantly exhibits a pentavalent oxidation state (i.e., +V) within the stability field of water. Cementitious materials (concrete, mortar, and grout) are extensively utilized in LILW disposal systems as structural components and chemical agents for the stabilization of waste. Solubility defines the source term (i.e., upper concentration limit) in the repository system. However, the solubility behavior of Nb in cementitious systems at high pH remains ill-defined, and information available on the Nb solid phases controlling the solubility is scarce and often ambiguous. Sorption on cementbased materials is one of the main mechanisms controlling the retention of niobium(V) in a LILW repository, and distribution coefficients (Rd) are necessary to evaluate the retention capacity by sorption in the safety assessment of disposal systems. Available sorption data of Nb(V) on cement showed a large discrepancy in Rd, moreover, no sorption data is available for Nb(V) under conditions characterizing the first degradation stage of cement (young cement condition) at pH 13 – 13.5. In this context, the solubility of Nb was extensively investigated in porewater conditions representative of the cement degradation stage I, as well as in CaCl2-Ca(OH)2 systems. Special focus was given to the accurate characterization of the solubility-controlling solid niobium phases. We also studied the sorption of Nb(V) by hardened cement pastes (HCP) and calcium silicate hydrates (CSH, major hydrate of HCP). This work provides the results on Rd, sorption isotherm and sorption mechanisms of Nb(V). Besides, the impact of ISA (polyhydroxycarboxylic acid generated by the degradation of cellulose) on Nb(V) sorption and the dissolution of cement materials was investigated.
        58.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is intended to determine the antimicrobial resistance properties and class 1 integrons of 30 Citrobacter freundii strains isolated from pet turtles in order to determine their threat to human health. Citrobacter freundii isolates were isolated and identified by employing biochemical tests and 16SrRNA gene sequencing. Disc diffusion test and PCR amplification were employed to detect antimicrobial resistance patterns and genes, respectively. Ampicillin, amoxicillin, cephalothin and nalidixic acid resistance were observed among all isolates. Rifampicin and cefoxitin resistance was the second most prevalent and observed in 97% of the isolates, respectively. All isolates scored multiple antimicrobial resistance (MAR) indices ≥ 0.2. Aminoglycoside resistant genes were the most prevalent. aac(3')-IIa was detected in 80% of the isolates followed by aphAI-IAB and strA-strB genes in 33% and 50% of the isolates, respectively. β-lactamase encoding blaTEM, blaCTX and blaSHV genes were detected in 53%, 43% and 17% of the isolates, respectively. tetA and tetB genes were the only tetracycline resistance genes detected in 17% and 10% of the isolates, respectively. Class 1 integron integrase encoding intI1 gene (47%) and dfrA17-aadA5 gene cassette array (7%) were also detected. Pet turtle-borne multidrug-resistant C. freundii is a reservoir of antimicrobial resistance determinants in the domestic environment which poses a risk of infection.
        4,000원
        59.
        2022.09 구독 인증기관·개인회원 무료
        Climate change has severely impacted food security and agricultural productivity in Africa. The scarcity of rains and the severe drought affecting the Sub-Saharan and the horn of Africa have impoverished the soil, and water resources, and have caused the death of livestock in countries like Sudan, Ethiopia, Kenya, Niger, and etc. On the other hand, the usage of chemical fertilizers for soil and crop nutrients is becoming an economic and environmental burden for African farmers. Thus, the necessity to implement sustainable agricultural technics to maintain and improve soil fertility by applying natural nutrients obtained from livestock manure while livestock is fed with crop residues in a single agricultural area. Although this farming system offers environmental and economic benefits to farmers, particularly in the rural and semi-urban areas, its implementation is very low in Africa because of: 1) constant migration of herders in the search of green pasture for livestock, making the collection of manure difficult, 2) religious and traditional beliefs considering animal waste as not being pure to be applied on crops, 3) conflicts between herders and farmers over the control of water resources and arable lands, making the cohabitation of livestock and crops in one farmland unlikely, and 4) the habit of crop residues burning, which is not just harmful to the environment but also a waste of natural livestock fed. Based on the reviewed literature, the Korea-Africa Food and Agriculture Cooperation Initiative (KAFACI) plans to develop and implement an integrated crop-livestock project in KAFACI member countries with the mission 1) to diffuse the importance of using natural nutrients for improving soil fertility and enhancing crop and livestock productivity in Africa, 2) to train researchers and farmers on new technologies for manure treatments, 3) to demonstrate the benefits of using livestock manure for soil fertility, crops nutrients, while using crop residues as livestock nutrients, and 4) contribute to enhancing sustainable agriculture in Africa through the reduction of greenhouse gas by reducing livestock’s waste and crop residues burning.
        60.
        2022.09 구독 인증기관·개인회원 무료
        The Democratic Republic of Congo (DR Congo) is a central African country, abundant with large and various agro-ecological landscapes suitable for the cultivation of various crops, water resources, and a young manpower. However, the country is facing a severe food crisis, exposing around 27 million people, among which 4 million undernourished children to famine according to the World Food Program. To better understand the paradox of the country with huge agricultural potential being one of the countries with the largest number of people in food distress in 2022, we reviewed the DR Congo's current agricultural potentials and challenges, and it was observed that the country's low agricultural productivity is mainly due to low governmental human and technological investment in agricultural research, which is characterized by insufficient training of researchers, limited research budget, and lack of updated technologies. Also, the country's immensity and poor transport infrastructures make the movement and commercialization of crops difficult in the country. Based on the data reviewed, the Korea-Africa Food & Agriculture Cooperation Initiative, an organization in which the DR Congo is a member country, proposes a reform of the country's agricultural policies 1) to set a proper vision for the country's Agricultural research and productivity, 2) to design a proper structure assigning the roles of every organization involved in agriculture at the national or provincial level, 3) to improve the government investment in young researchers' capacity building and motivation, 4) to define how cooperation with international organizations could contribute to the enhancement of the country's agricultural development.
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