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        검색결과 5,461

        1.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 한국산 미기록속인 고수씨살이좀벌속(신칭) 및 미기록종인 고수씨살이좀벌(신칭)과 긴고수씨살이좀벌(신칭)을 처음으로 보 고한다. 본 논문에서는 한국산 고수씨살이좀벌속(신칭)의 검색표와 두 미기록종의 재기재문 및 사진을 제공한다.
        4,000원
        2.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        꼬마꽃벌과의 1종, Lasioglossum (Hemihalictus) sphecodicolor이 국내에서 처음 확인되었다. 이 종에 대한 암컷의 진단 특징과 분포, 형태적 형질 도판, 한국 내 Hemihalictus아속의 종에 대한 분류키를 수록한다.
        4,000원
        3.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We study quasi-spherical, supersonic accretion flows around black holes using high-accuracy numerical simulations. We describe a code, the Lagrangian Total Variation Diminishing (TVD), and a remap routine to address a specific issue in the Advection Dominated Accretion Flow (ADAF) that is, appropriately handling the angular momentum even near the inner boundary. The Lagrangian TVD code is based on an explicit finite difference scheme on mass-volume grids to track fluid particles with time. The consequences are remapped on fixed grids using the explicit Eulerian finitedifference algorithm with a third-order accuracy. Test results show that one can successfully handle flows and resolve shocks within two to three computational cells. Especially, the calculation of a hydrodynamical accretion disk without viscosity around a black hole shows that one can conserve nearly 100% of specific a ngular momentum in one-and twodimensional cylindrical coordinates. Thus, we apply this code to obtain a numerically similar ADAF solution. We perform simulations, including viscosity terms in one-dimensional spherical geometry on the non-uniform grids, to obtain greater quantitative consequences and to save computational time. The error of specific angular momentum in Newtonian potential is less than 1% between r~10rs and r~10 4 rs, where rs is sink size. As Narayan et al. (1997) suggested, the ADAFs in pseudo-Newtonian potential become supersonic flows near the black hole, and the sonic point is rsonic~5.3rg for flow with α =0.3 and  =1 .5. Such simulations indicate that even the ADAF with  =5/3 is differentially rotating, as Ogilvie (1999) indicated. Hence, we conclude that the Lagrangian TVD and remap code treat the role of viscosity more precisely than the other scheme, even near the inner boundary in a rotating accretion flow around a nonrotating black hole.
        4,300원
        6.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the key challenges for the commercialization of carbon nanotube fibers (CNTFs) is their large-scale economic production. Among CNTF spinning methods, surfactant-based wet spinning is one of the promising techniques for mass producing CNTFs. Here, we investigated how the coagulation bath composition affects the spinnability and the properties of CNTFs in surfactant-based wet spinning. We used acetone, DMAc, ethanol, and IPA as coagulants and analyzed the relationship between coagulation bath composition and the properties of CNTFs in terms of kinetic and thermodynamic coagulation parameters. From a kinetic perspective, we found that a low mass transfer rate difference (MTRD) is favorable for wet spinning. Based on this finding, we mixed the coagulant bath with solvent in a proper ratio to reduce the MTRD, which generally improved the wet spinning. We also showed that the coagulation strength, a thermodynamic parameter, should be considered. We believe that our research can contribute to establishment of surfactant-based wet spinning of CNTFs.
        4,500원
        7.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electrochemical properties of a CFX cathode were improved by defluorination of the surface with a N2 plasma and using a silica wafer. Compared to the N2 plasma treatment alone, when the CFX and silica were reacted together, the C-F bonds were modified and the surface was etched efficiently, so defluorination was enhanced. An electrochemical analysis confirmed that Half-cells prepared by treating CFx and silica with nitrogen plasma exhibited a capacity of about 400 mAh/g at 5C. In addition, it was confirmed that the loss of charge transfer was reduced by up to 71% compared to that for pristine CFX. As shown by a GITT analysis, when the CFx and silica were treated with N2 plasma together, the ion conductivity gradually increased due to a decrease in the ion diffusion barriers and the formation of a carbon layer. Therefore, this is a simple and effective way to improve the conductivities of CFX cathode materials with the energy of a N2 plasma and the silica-fluorine reaction.
        4,000원
        8.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper explores the potential application of carbon nanotubes (CNTs) in the construction industry, as CNTs can effectively serve as nano-fillers, bridging the voids and holes in cement structures. However, the limited dispersibility of CNTs in water necessitates the use of dispersing agents for achieving uniform dispersion. In this study, two kinds of cement superplasticizers, polycarboxylate ether (PCE) and sulfonated naphthalene formaldehyde (SNF) were employed as dispersing agents to improve the interfacial affinity between CNTs and cement, and to enhance the strength of the cement nanocomposites. Contact angle experiments revealed that the utilization of PCE and SNF effectively addressed the interface issues between CNTs and cement. As a result, the cement nanocomposite with a CNT to PCE ratio of 1:2 exhibited an approximately 6.6% increase in compressive strength (73.05 MPa), while the CNT:SNF 1:2 cement composite showed a 4.7% increase (71.72 MPa) compared to plain cement (68.52 MPa). In addition, the rate of crack generation in cement nanocomposites with CNTs and dispersing agents was found to be slower than that of plain cement. The resulting cement nanocomposites, characterized by enhanced strength and durability, can be utilized as safer materials in the construction industry.
        4,600원
        9.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It was found in this study that fluorinated microporous carbon aerogels with enhanced hydrophobicity could be successfully prepared by direct fluorination to separate water-in-oil emulsions at high flux. The fluorinated carbon aerogel (F-CA) surface treated by the fluorination method had a water contact angle of 151.2° and could immediately absorb oil. In addition, the unique network structure of F-CA and its hydrophobicity allow surfactant-stabilized water-in-oil emulsions to be effectively and simply separated under gravity without requiring external forces such as vacuum or pressurization. The network structure of F-CAs consists of randomly connected spherical particles that form fluorinated permeation channels, which induce high flux during emulsion separation. The F-CA spherical particles have nanosized pores and high hydrophobicity, which repel and trap water droplets to increase the separation purity. Therefore, F-CA exhibited excellent performance, such as high filtrate purity (up to 99.9954%) and flux (up to 11,710 L/m2h). Furthermore, F-CA reusability was demonstrated as it did not lose its hydrophobicity and maintained its performance even after repeated use. This type of aerogel has great potential to be utilized throughout various environmental fields, including oil remediation.
        4,200원
        10.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, laser-induced graphene oxide (LIGO) was synthesized through a facile liquid-based process involving the introduction of deionized (DI) water onto polyimide (PI) film and subsequent direct laser irradiation using a CO2 laser (λ = 10.6 μm). The synthesized LIGO was then evaluated as a sensing material for monitoring changes in humidity levels. The synthesis conditions were optimized by precisely controlling the laser scribing speed, leading to the synthesis of LIGO with different structural characteristics and varying oxygen contents. The increased number of oxygen-containing functional groups contributed to the hydrophilic properties of LIGO, resulting in a superior humidity sensing capabilities compared with laser-induced graphene (LIG). The LIGO-based sensors outperformed LIG-based sensors, demonstrating approximately tenfold higher sensing responsivity when detecting changes at each humidity level, along with 1.25 to 1.75 times faster response/recovery times, making LIGO-based sensors more promising for humidity-monitoring applications. This study demonstrated laser ablation in a renewable and natural precursor as an eco-friendly and energy-efficient approach to directly synthesize LIGO with controllable oxidation levels.
        4,500원
        11.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the negative perceptions (veganphobia) held by consumers toward vegan diets and fashion and aims to foster a genuine acceptance of ethical veganism in consumption. The textual data web-crawled Korean online posts, including news articles, blogs, forums, and tweets, containing keywords such as “contradiction,” “dilemma,” “conflict,” “issues,” “vegan food” and “vegan fashion” from 2013 to 2021. Data analysis was conducted through text mining, network analysis, and clustering analysis using Python and NodeXL programs. The analysis revealed distinct negative perceptions regarding vegan food. Key issues included the perception of hypocrisy among vegetarians, associations with specific political leanings, conflicts between environmental and animal rights, and contradictions between views on companion animals and livestock. Regarding the vegan fashion industry, the eco-friendliness of material selection and design processes were seen as the pivotal factors shaping negative attitudes. Furthermore, the study identified a shared negative perception regarding vegan food and vegan fashion. This negativity was characterized by confusion and conflicts between animal and environmental rights, biased perceptions linked to specific political affiliations, perceived self-righteousness among vegetarians, and general discomfort toward them. These factors collectively contributed to a broader negative perception of vegan consumption. In conclusion, this study is significant in understanding the complex perceptions and attitudes that consumers hold toward vegan food and fashion. The insights gained from this research can aid in the design of more effective campaign strategies aimed at promoting vegan consumerism, ultimately contributing to a more widespread acceptance of ethical veganism in society.
        5,100원
        12.
        2024.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Democratic People’s Republic of Korea (DPRK) has produced weapon-grade plutonium in a graphite-moderated experimental reactor at the Yongbyon nuclear facilities. The amount of plutonium produced can be estimated using the Graphite Isotope Ratio Method (GIRM), even without considering specific operational histories. However, the result depends to some degree on the operational cycle length. Moreover, an optimal cycle length can maximize the number of nuclear weapons made from the plutonium produced. For conservatism, it should be assumed that the target reactor was operated with an optimal cycle length. This study investigated the optimal cycle length using which the Calder Hall MAGNOX reactor can achieve the maximum annual production of nuclear weapons. The results show that lower enrichment fuel produced a greater number of critical plutonium spheres with a shorter optimal cycle length. Specifically, depleted uranium (0.69wt%) produced 5.561 critical plutonium spheres annually with optimal cycle lengths of 251 effective full power days. This research is crucial for understanding DPRK’s potential for nuclear weapon production and highlights the importance of reactor operational strategy in maximizing the production of weapons-grade plutonium in MAGNOX reactors.
        4,000원
        13.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        총채벌레목 관총채벌레과의 미기록속인 Pachyliothrips속에 속하는 단일종 Pachyliothrips zelkovae Okajima, 2006 (느티나무관총채벌레, 신 칭)을 한국에서 처음으로 보고한다. 성충의 형태적 특징과 형태 사진을 수록하였다.
        4,000원
        14.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to evaluate the efficiency of combining acidification with adsorbents (zeolite and biochar) to mitigate the environmental impacts of pig slurry, focusing on ammonia (NH3) emission and nitrate (NO3 -) leaching. The four treatments were applied: 1) pig slurry (PS) alone as a control, 2) acidified PS (AP), 3) acidified pig slurry with zeolite (APZ), and 4) acidified pig slurry with biochar (APB). The AP mitigates NH3 emission and NO3 - leaching compared to PS alone. Acidification reduced the cumulative NH3 emission and its emission factor by 35.9% and 12.5%, respectively. The APZ and APB increased NH4 +-N concentration, with the highest level in APB, compared to AP. The NH4 + adsorption capacity of APB (0.90 mg g-1) was higher than that of APZ (0.63 mg g-1). The APB and APZ treatments induced less NH3 emission compared to AP. The cumulative NH3 emission was reduced by 12.2% and 27.6% in APZ and APB, respectively, compared to AP treatment. NO3 - leaching began to appear on days 12 and 13, and its peak reached on days 16 and 17, which were later than AP. The cumulative NO3 - leaching decreased by 17.7% and 25.0% in APZ and APB, respectively, compared to AP treatment. These results suggest that combining biochar or zeolite with acidified pig slurry is an effective method to mitigate NH3 emission and NO3 - leaching, with biochar being particularly effective.
        4,000원
        15.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study emphasizes R&D as a management strategy for small and medium-sized manufacturing enterprises (SMEs) to achieve competitive advantage and aims to analyze the impact of innovation resistance, prior knowledge, and technological capability on the intention to adopt R&D. The research targeted 403 decision-makers from SMEs that have not adopted R&D. The analysis revealed the following key findings: As a result, both technical capabilities and prior knowledge had a negative effect on innovation resistance. In addition, technological capabilities and prior knowledge had a positive effect on adoption intention, and innovation resistance had a negative effect on acceptance intention. The indirect effects of technical capabilities and prior knowledge both had a positive impact. In addition, we tested whether dependency on partners and trading organizations that accepted R&D had a moderating effect, but it was not significant. The academic implications of this study provide a detailed analysis of how prior knowledge and technological capability affect innovation resistance in SMEs and verify the intention to adopt R&D. The practical implications suggest a direction for small and medium-sized enterprises to reduce innovation resistance in accepting R&D, and companies need to recognize the suitability of R&D and recognize the importance of technological capabilities and prior knowledge in order to reduce innovation resistance.
        4,000원
        16.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        From 2020, Korean Animal and Plant Quarantine Agency has reset the withdrawal time (WT) for veterinary drugs typically used in livestock in preparation for the introduction of positive list system (PLS) program in 2024. This study was conducted to reset the MRL for tiamulin (TML) in broiler chickens as a part of PLS program introduction. Forty-eight healthy Ross broiler chickens were orally administered with TML at the concentration of 25 g/L (TML-1, n=24) and 50 g/L (TML-2, n=24) for 5 days through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 1, 2, 3 and 5 days, respectively. According to the previously established analysis method, residual TML concentrations in poultry tissues were determined using LC-MS/MS. In TML-1, TML in all tissues was detected less than LOQ at 2 days after drug treatment. In TML-2, TML in liver and kidney was detected more than LOQ at 2 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal periods of TML-1 and TML-2 in poultry tissues were established to 0 and 2 days, respectively. In conclusion, the estimated WT of TML in poultry tissues is shorter than the current WT recommendation of 5 days for TML in broiler chickens.
        4,000원
        17.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the advent of the 4th Industrial Revolution, changes in the market environment and employment environment are accelerating due to smart technological innovation, and securing professional manpower and developing human resources for domestic small and medium-sized enterprises is becoming very important. Recently, most of the domestic small and medium-sized enterprises are experiencing hiring difficulties, and the development and training of human resources to overcome this is still lacking in systemization, despite much support from the government. This reflects the reality that it is not easy to invest training costs and time to adapt new employees to small and medium-sized businesses. Based on these problems, the work-study parallel project was introduced to cultivate practical talent in small and medium-sized businesses. Work-study parallel training is carried out in the form of mentoring between corporate field teachers and learning workers in actual workplaces, and even if the training is the same, there are differences depending on the learner's attitude, learning motivation, and training achievement. Ego state is a theory that can identify personality types and has the advantage of being able to understand and acknowledge oneself and others and intentionally improve positive factors to induce optimized interpersonal relationships. Accordingly, the purpose of this study is to analyze the attitudes of learning workers, who are the actual subjects for improving the performance of work-study parallel projects and establishing a stable settlement within the company, based on their ego status. Through this study, we aim to understand the impact of the personality type of learning workers on training performance and to suggest ways to improve training performance through work-study parallelism.
        4,000원
        18.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the virucidal efficacy of a chlorine dioxide (ClO2) gas-generating fumigation disinfectant consisting of sodium chlorate solution (25% sodium chlorate) and reaction solution against avian influenza virus (AIV). After AIV suspensions had been deposited on stainless steel carriers, the 9 dried carriers were exposed to the fumigant (sodium chlorate solution: 8.5, 17, 34, 50, and 100 mL) in a 25-m³ test room for 2, 3, and 4 h, respectively. Thereafter, all carriers were submerged in a neutralizing solution (20% fetal bovine serum) to scrape off the surviving viruses, and the respective suspensions were diluted. Each diluent was inoculated into the allantoic membrane of five 10-day-old embryos. After incubation for 5 days at 37℃, AIV viability in the collected allantoic fluids was examined, and the egg infectious dose 50 (EID50) was calculated. When the carrier was exposed to ClO2 gas generated from reacting 34 mL of the fumigant for 3 h, the AIV titer reduced by more than 104.0 EID50/carrier compared to the control, which was exposed to the fumigant without inoculation of AIV suspension. In addition, the control was non-toxic to the embryos.
        4,000원
        19.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Obesity occurs when the body consumes more energy than it requires and uses less energy, resulting in the accumulation of fat, which increases the number and size of fat cells in the body. It causes high blood pressure, type 2 diabetes, and joint crowding, making it difficult to fully treat. We investigated the effects of chito oligosaccharide(CHO) functional material, which suppresses fat accumulation, restores dyslipidemia values, and has no side effects.In this study, we investigated the ameliorative effects of CHO on obese mice fed a high-fat diet. The experimental groups were divided into 5 groups (n=10) of C57BL/6 mice: normal control (N), control group (C), and chito oligosaccharide low concentration (L), medium concentration (M), and high concentration (H) groups. We tested whether CHO has an effect on obesity through body weight and adipose tissue weighing, serum lipid testing, and histological examination. Experimental analysis showed that CHO reduced body weight and adipose tissue weight, improved the concentrations of TCHO, TG, HDL, and LDL, which are factors for dyslipidemia diagnosis, and decreased the diameter size of adipose tissue. These results suggest that CHO alleviates the levels of fat growth inhibition and dyslipidemia levels in obese-induced mice, and has a positive effect on obesity.
        4,000원
        20.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Caprine cryptosporidiosis mainly occurs in young goats, with morbidity rates of 80%–100% and mortality over 50% in goat kids. However, limited research has been conducted on the impact of Cryptosporidium parvum, a diarrhea-causing pathogen, on the intestinal microbiota of goat kids. In this study, 16S rRNA-based metataxonomic analysis was performed to compare the microbial diversity and abundance of the gut microbiota between C. parvum-infected and uninfected goat kids. In total, 12 goat fecal samples were collected, including seven naturally C. parvum-infected and five uninfected goats from Chungcheongbuk-do, Korea. After amplification of the V3–V4 hypervariable region of the bacterial 16S rRNA, high-throughput sequencing was performed. The results showed differences in the microbial composition between C. parvum-infected and uninfected groups based on beta diversity. Firmicutes and Bacteroidetes were the most dominant phyla in both groups. However, no significant difference was observed in the Bacteroidetes/Firmicutes ratio between the two groups. Compared with the uninfected group, the C. parvum-infected group showed significantly higher abundances of Tyzzerella nexillis, Lactobacillus johnsonii, Butyricicoccus pullicaecorum, Enterococcus raffinosus, Enterococcus faecalis, and Negativicoccus massiliensis, and significantly reduced abundances of Aerococcus vaginalis, Faecalicoccus pleomorphus, Oribacterium parvum, and Coprococcus comes. These findings indicate that C. parvum infection, which is associated with diarrhea in neonatal goats, induces alterations in the caprine gut microbiota.
        4,300원
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