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        검색결과 1,054

        1.
        2024.04 구독 인증기관·개인회원 무료
        Six new species are described that are members of the New Zealand endemic genus Adalmus Reitter (Staphylinidae: Pselaphinae: Euplectitae: Trichonychini: Panaphantina): A. bullerensis sp. nov., A. kanierensis sp. nov., A. karekarensis sp. nov., A. mangamukaensis sp. nov., A. puberilumbus sp. nov., and A. serrilumbus sp. nov. In addition, Dalmisus Sharp is placed as a junior synonym of Adalmus (gen. syn.) and the species Dalmisus batrisodes Sharp, 1886, Plectomorphus longiceps Broun, 1913 and P. longipes Broun, 1912 are placed as junior synonyms of A. velutinus Reitter, 1885 spp. syn. Also, P. rugiceps Broun, 1921 is transferred to the genus Adalmus, comb. nov. Adalmus now holds eight species.
        2.
        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.
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This work involves the development of a novel waste-derived carbon dots (CDs) conjugated with silver (Ag) nanohybrid system-based Fluorescence Resonance Energy Transfer (FRET) sensor for the detection of melamine. CDs and Ag nanoparticles served as energy donors and energy acceptors, respectively. CDs were synthesized from orange peel waste through a combined hydrothermal and ultra-sonication route. The synthesized CDs had hydroxyl, amino, and carboxyl groups on their surface, explaining that waste-derived CDs can act as reducing and stabilizing agents and showed strong absorption and fluorescence emission at 305 and 460 nm, respectively. The bandgap, linear refractive index, conduction band, and valance band potential of CDs were observed to be 2.86, 1.849, 1.14, and 4.002 eV, respectively. No significant difference was observed in the fluorescence properties at different pH (acid and alkaline) and ionic concentrations. Given their fluorescent nature, the synthesized CDs were used for the detection of melamine. The fluorescence of CDs was found to be quenched by Ag+ due to the FRET energy transfer between CDs to Ag. Notably, the zeta potential of Ag@CDs was changed from − 28.7 mV to − 30.6 mV after the incorporation of Ag+. Ag@CDs showed excellent selectivity and sensitivity toward the sensing of melamine in the aqueous solutions with the limit of detection ~ 0.85 μM. Increasing the melamine level also raises the FL intensity of Ag@CDs. The substrate was effectively used in the detection of melamine in milk as a real application and the recovery percentage was found to be 98.03%. Moreover, other adulterants such as urea and formaldehyde can be detected selectively by Ag@CDs. Overall, the synthesized Ag@CDs can be used as an efficient material for sensing applications involving such food adulterants.
        4,600원
        4.
        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
        6.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The widespread and extensive use of glyphosate in agriculture has raised concerns about its potential impact on the quality and safety of agricultural products. Conventional detection methods require long analysis times, making them impractical for the rapid detection of large quantities of samples. Therefore, developing a fast and simple detection system for glyphosate pesticide residues is urgent. In this study, the development of a facile fluorescence probe synthesized using a simple one-pot hydrothermal method for the determination of glyphosate is an important step toward addressing the need for a fast and simple detection system. The present sensor was created using bovine serum albumin (BSA) as a precursor, and the sensor operates by producing an “off–on” fluorescent signal. The bovine albumin-derived BSA-CDs emitted light yellow fluorescence, but this fluorescence was quenched (or suppressed) by the presence of Cu2+ ions. However, the fluorescence can be restored by the presence of glyphosate, which interacts with the Cu2+ ions to form a complex and release the BSACDs from suppression. The functional groups in glyphosate can capture Cu2+ and break the BSA-CDs/Cu2+ combinatorial system. The BSA-CDs/Cu2+ fluorescence quenching system had good selectivity for glyphosate. The detection limit of the BSA-CD/Cu2+ fluorescence sensor was 0.05 μg/mL. This developed method was utilized to successfully detect glyphosate in Chinese wheat. The average recoveries ranged from 98.9 to 100.7%, with a relative standard deviation < 3.0%, showing good prospects for practical applicability.
        4,200원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the biogeochemistry management (BGC-MAN) model was applied to North and South Korea pine and oak forest stands to evaluate the Net Primary Productivity (NPP), an indicator of forest ecosystem productivity. For meteorological information, historical records and East Asian climate scenario data of Shared Socioeconomic Pathways (SSPs) were used. For vegetation information, pine (Pinus densiflora) and oak (Quercus spp.) forest stands were selected at the Gwangneung and Seolmacheon in South Korea and Sariwon, Sohung, Haeju, Jongju, and Wonsan, which are known to have tree nurseries in North Korea. Among the biophysical information, we used the elevation model for topographic data such as longitude, altitude, and slope direction, and the global soil database for soil data. For management factors, we considered the destruction of forests in North and South Korea due to the Korean War in 1950 and the subsequent reforestation process. The overall mean value of simulated NPP from 1991 to 2100 was 5.17 Mg C ha-1, with a range of 3.30-8.19 Mg C ha-1. In addition, increased variability in climate scenarios resulted in variations in forest productivity, with a notable decline in the growth of pine forests. The applicability of the BGC-MAN model to the Korean Peninsula was examined at a time when the ecosystem process-based models were becoming increasingly important due to climate change. In this study, the data on the effects of climate change disturbances on forest ecosystems that was analyzed was limited; therefore, future modeling methods should be improved to simulate more precise ecosystem changes across the Korean Peninsula through processbased models.
        4,500원
        8.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The mechanism of resonant light scattering in single-layer graphene is discussed. A new concept of electron–hole selfphotorecombination is proposed, which makes it possible to clearly separate the phenomena of resonant light scattering and resonant photoluminescence. It is established that Rayleigh resonant radiation has been found to consist of virtual and non-virtual components. It has been shown that Rayleigh radiation is mainly caused by resonant non-virtual optical transitions. The band of Rayleigh radiation due to resonant virtual transitions is quite wide, and the intensity is extremely low. On the basis of the presented theory, the results of numerical estimates of the linewidth and intensity of the Rayleigh band of single-layer graphene are in fairly good agreement with the experimental data.
        4,000원
        9.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Graphene is a suitable transducer for wearable sensors because of its high conductivity, large specific surface area, flexibility, and other unique considerable features. Using a simple, fast galvanic pulse electrodeposition approach, a unique nonenzymatic glucose amperometric electrode was successfully developed based on well-distributed fine Cu nanoparticles anchored on the surface of 3D structure laser-induced graphene. The fabricated electrode allows glucose detection with a sensitivity of 2665 μA/mM/cm2, a response time of less than 5 s, a linear range of 0.03–4.5 mM, and a LOD of 0.023 μM. It also detects glucose selectively in the presence of interfering species such as ascorbic acid and urea. These provide the designed electrode the advantages for glucose sensing in saliva with 97% accuracy and present it among the best saliva-range non-enzymatic glucose sensors reported to date for real-life diagnostic applications.
        4,600원
        10.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Flexible supercapacitors (FS) are ideal as power backups for upcoming stretchable electronics due to their high power density and good mechanical compliance. However, lacking technology for FS mass manufacturing is still a significant obstacle. The present study describes a novel method for preparing FS based on reduced graphene oxide (RGO) using the N+ plasma technique, in which N+ reduces graphene oxide on the surface of a cotton/polyester substrate. The effect of aloe vera (AV) as a natural reducing & capping agent and carbon nanotubes (CNT) as nanoconductors on the electrochemical performance of the electrodes is studied. FESEM and XPS were employed to investigate the electrodes' structural and chemical composition of electrodes. The galvanostatic charge–discharge curves of electrodes revealed the enhancement of the electrochemical activity of the as-prepared electrode upon additions of AV and CNT. The areal capacitance of the RGO, RGO/AV, and RGO/ AV/CNT supercapacitors at 5 mV/s was 511, 1244.5, and 1879 mF/cm2, respectively. The RGO electrode showed capacitive retention of 80.9% after 2000 cycles enhanced to 89.7% and 92% for RGO/AV and RGO/AV/CNT electrodes, respectively. The equivalent series resistance of the RGO electrode was 126.28 Ω, decreased to 56.62 and 40.06 Ω for RGO/AV and RGO/ AV/CNT electrodes, respectively.
        4,000원
        11.
        2023.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Exploring earth-abundant, highly effective and stable electrocatalysts for electrochemical water splitting is urgent and essential to the development of hydrogen (H2) energy technology. Iron-cobalt layered double hydroxide (FeCo-LDH) has been widely used as an electrocatalystfor OER due to its facile synthesis, tunable components, and low cost. However, LDH synthesized by the traditional hydrothermal method tends to easily agglomerate, resulting in an unstable structure that can change or dissolve in an alkaline solution. Therefore, studying the real active phase is highly significant in the design of electrochemical electrode materials. Here, metal-organic frameworks (MOFs) are used as template precursors to derive FeCo-LDH from different iron sources. Iron salts with different anions have a significant impact on the morphology and charge transfer properties of the resulting materials. FeCo-LDH synthesized from iron sulfate solution (FeCo-LDH-SO4) exhibits a hybrid structure of nanosheets and nanowires, quite different from other electrocatalysts that were synthesized from iron chloride and iron nitrate solutions. The final FeCo-LDH-SO4 had an overpotential of 247 mV with a low Tafel-slope of 60.6 mV dec-1 at a current density of 10 mA cm-2 and delivered a long-term stability of 40 h for the OER. This work provides an innovative and feasible strategy to construct efficient electrocatalysts.
        4,000원
        12.
        2023.10 구독 인증기관·개인회원 무료
        Goniaceritae is the most speciose supertribe of the subfamily Pselaphinae with more than 3,000 species worldwide. Brachyglutini is the only tribe within New Zealand Goniaceritae, comprised of 8 genera. Physobryaxis Hetschko is monotypic genus of the subtribe Brachyglutina. Although the adults of P. inflatus is close to the members of genus Gastrobothrus Broun, 1882, it is characterized by median antebasal fovea and antebasal sulcus on pronotum. In this study, we report six species of Physobryaxis examining 21 specimens. Illustrations of the habitus, diagnostic characters including male genitalia, and key to the species are also provided. Additionally, we present a distributional map divided into areas based on Crosby’s code.
        17.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Evaluating the effectiveness of the radiation protection measures deployed at the Centralized Radioactive Waste Management Facility in Ghana is pivotal to guaranteeing the safety of personnel, public and the environment, thus the need for this study. RadiagemTM 2000 was used in measuring the dose rate of the facility whilst the personal radiation exposure of the personnel from 2011 to 2022 was measured from the thermoluminescent dosimeter badges using Harshaw 6600 Plus Automated TLD Reader. The decay store containing scrap metals from dismantled disused sealed radioactive sources (DSRS), and low-level wastes measured the highest dose rate of 1.06 ± 0.92 μSv·h−1. The range of the mean annual average personnel dose equivalent is 0.41–2.07 mSv. The annual effective doses are below the ICRP limit of 20 mSv. From the multivariate principal component analysis biplot, all the personal dose equivalent formed a cluster, and the cluster is mostly influenced by the radiological data from the outer wall surface of the facility where no DSRS are stored. The personal dose equivalents are not primarily due to the radiation exposures of staff during operations with DSRS at the facility but can be attributed to environmental radiation, thus the current radiation protection measures at the Facility can be deemed as effective.
        4,200원
        18.
        2023.07 구독 인증기관·개인회원 무료
        As the popularity of gaming has increased, the importance and effectiveness of in-game advertisements have become more relevant to marketers. However, despite this development, both marketing academics and practitioners do not fully comprehend how consumers respond to in-game advertisements. This study focuses on the dynamics associated with in-game advertisements, considering the privacy concerns and ad relevance expectations of consumers/gamers.
        19.
        2023.07 구독 인증기관·개인회원 무료
        As cryptocurrencies continue to gain viability as an asset class, institutional investors and publicly traded firms are beginning to enter into positions in digital currencies. While generating profits may be the primary purpose, corporations also wish to advertise to their stakeholders that they are keeping up-to-date with latest technological developments, trends, and cutting-edge investment opportunities in enhancing the wealth of the shareholders. The marketing and financial signals with the involvement in blockchain platforms and digital currencies intend to demonstrate the efficiency of corporate operations, and the agility in the utilization of the retained funds. What firms may not be considering however, is the effect these assets may have on their risk profiles. This paper aims at measuring the effect of digital currencies on the risk and returns of publicly traded companies, deciphering the motives behind holding a cryptocurrency as an asset, and determining whether one reason for holding is more impactful than another. Four largest publicly traded holders as well as four of the most prominent digital currencies are explored. The findings from the study contribute to the literature in corporate risk reporting, in marketing and financial motivations of digital currency holdings, and in digital currency risks. The conclusions of the study also make a case for firm transparency through detailed reports of the risk effects of digital currency holdings.
        20.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Germ cells undergo towards male or female pathways to produce spermatozoa or oocyte respectively which is essential for sexual reproduction. Mesenchymal stem cells (MSCs) have the potential of trans-differentiation to the multiple cell lineages. Methods: Herein, rat MSCs were isolated from bone marrow and characterized by their morphological features, expression of MSC surface markers, and in vitro differentiation capability. Results: Thereafter, we induced these cells only by retinoic acid supplementation in MSC medium and, could able to show that bone marrow derived MSCs are capable to trans-differentiate into male germ cell-like cells in vitro. We characterized these cells by morphological changes, the expressions of germ cell specific markers by immunophenotyping and molecular biology tools. Further, we quantified these differentiated cells. Conclusions: This study suggests that only Retinoic acid in culture medium could induce bone marrow MSCs to differentiate germ cell-like cells in vitro . This basic method of germ cell generation might be helpful in the prospective applications of this technology.
        4,000원
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