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        검색결과 52,031

        767.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        중국 국가 통계국에서 발표한 데이터에 따르면, 2022년 60세 이상 인구는 전체의 19.6%이며, 2035년에는 4억을 초과하여 고령화 사회의 단계에 접어들 것이라고 한다. 질병의 발병률이 매우 높은 고령층은 의약품의 복용 과정에서 주의해야 할 점이 많은 반면, 이에 대한 이해가 부족하여 의약품의 복용에 따른 잠재적인 위험에 항상 노출되어 있다. 이에 따라 의약품 포장에 대한 고령층의 요구를 수용하고, 의약품 복용의 정확성과 편의성을 향상시키는 문제는 당면의 과제가 되고 있다. 본 연구는 디지털 휴먼 기술을 도입하여 의약품 포장의 혁신적인 디자인을 강구하고, 이를 통해 고령층의 의약품 관련 문제에 대한 해결을 목표로 한다. 의약품 포장 디자인에 디지털 휴먼 기술을 적용하는 것은 최근 디지털 발전의 추세에 부합하며, 고령층을 대상으로 하는 의약품 포장 디자인에 새로운 사로를 제공할 수 있다. 따라서 본 연구는 문헌 분석법 및 사례 분석법 등을 통해 고령층을 대상으로 하는 의약품 포장 디자인의 발전 현황을 파악하여, 기존 제한적인 정보만을 제공하던 단일 시각 형태의 전통적인 의약품 포장 디자인의 한계를 극복하고, 새로운 디자인 방안을 제시하여 고령층이 더 다양한 방식으로 의약품 포장을 통해 필요한 정보를 인식할 수 있도록 만들고자 하였다. 기존 의약품 포장 디자인에 대한 분석을 바탕으로 본 연구는 디지털 휴먼 기술과 의약품 포장의 결합에 대한 타당성을 도출했고, 실례를 통해 디지털 휴먼 기술이 의약품 포장에 있어 상당한 응용 가치와 잠재력을 가지고 있다는 사실을 검증하였다.
        8,000원
        768.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4-Nitrophenol (4NP) is a vital intermediate in organic industries, and its exploitation creates serious environmental issues. We propose a fluorescence quenching-based strategy with nitrogen and sulfur co-doped carbon dots (NS-CDs) for highly sensitive 4NP detection with excellent selectivity. The NS-CDs are produced through the hydrothermal process, in which citric acid serves as a carbon source and cysteamine hydrochloride as a source of N and S. The effect of doping was also studied by synthesizing undoped CDs and examining their properties. As-developed NS-CDs exhibit a bright cyan blue color with maximum emission centered at 465 nm. The fluorescence of NS-CDs is significantly quenched in an approximately linear fashion with increasing 4NP concentration (7.5–97.5 μM). The inner filter effect (IFE) and static quenching (SQ) between NS-CDs and 4NP are responsible for such fluorescence reduction. The fluorimetry technique enables the quantification of 4NP with a limit of detection (LOD) of about 0.028 μM. Moreover, the fluorescence quenching is tested for several other chemical compounds but they generate false quenching signals; only 4NP leads to fluorescence quenching of NS-CDs, demonstrating excellent selectivity. The “turn-off” fluorescence properties and visually apparent color change of the fluorescent probe reveal the excellent performance for 4NP sensing. The NS-CDs’ capability of quantifying 4NP in real water samples (tap water and drinking water) produces an excellent recovery rate ranging between 96.24 and 98.36%.
        4,500원
        769.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this investigation, we synthesized a novel quaternary nanocomposite, denoted as RGO-Ba(OH)2/CeO2/TiO2, through a straightforward and cost-effective solid-state synthesis approach. The as-prepared composites underwent a series of comprehensive characterizations, including XRD, FTIR, TGA-DTA, XPS, SEM, EDAX, and TEM analyses, affirming the successful synthesis of a quaternary nanocomposite with well-interconnected nanoparticles, nanorods, and sheet-like structures. Further, our electrochemical performance evaluations demonstrated that the electrochemical capacitance of the RGO-Ba(OH)2/CeO2/ TiO2 nanocomposite achieved an impressive value of 445 F g− 1 at a current density of 1.0 A g− 1, particularly when the mass ratio of CeO2 and TiO2 was maintained at 90:10. Furthermore, the specific capacitance retained a remarkable 65% even after 2000 cycles at a current density of 6 A g− 1 in a 3 mol KOH electrolyte. Comparatively, this outstanding electrochemical performance of the RGO-Ba(OH)2/CeO2/TiO2 (90:10) nanocomposite can be attributed to several factors. These include the favorable electrical conductivity and large specific surface area provided by graphene, TiO2, and Ba(OH)2, the enhanced energy density and extended cycle life resulting from the presence of CeO2, and the synergistic contributions among all four components. Therefore, the RGO-Ba(OH)2/CeO2/TiO2 nanocomposite emerges as a highly promising electrode material for supercapacitors.
        4,000원
        770.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to identify and analyze the effects of both isothermal heat treatment temperature and residence time on the formation of mesophase in coal tar pitch, especially with respect to its microstructural and crystalline evolution. The formation and growth of mesophase resulted in a decrease in d002 and an increase in Lc, and the degree of such variation was larger when the isothermal heat treatment temperature was higher. In isothermally heat-treated pitch, two distinct domains were observed: less developed crystalline carbon (LDCC) and more developed crystalline carbon (MDCC). When pitch was isothermally heat-treated at 375 °C for 20 h, d002 was 4.015 Å in the LDCC and 3.515 Å in the MDCC. Higher isothermal heat-treatment temperatures accelerated the formation, growth, and coalescence of mesophase. Indeed, in the pitch specimen isothermally heat-treated at 425 °C for 20 h, d002 was 3.809 Å in the LDCC and 3.471 Å in the MDCC. The evolution of mesophase was characterized by pronounced inflection points in d002 curves. It was found that the emergence of these inflection points coincided with pronounced changes in the microstructure of mesophase. This finding confirmed the relationship between inflection points in d002 and the microstructure of mesophase.
        4,200원
        771.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Wearable sensors with highly flexible and sensitive characteristics have attracted research interests in the promising field of electronic skin, health monitoring, and soft robotics. However, the developing of high-performance piezoresistive sensor is full of challenges due to the expensive equipment and complex procedures. Herein, we fabricate a reduced graphene oxide/ polyurethane composite sponge (GPCS) pressure sensor combining with dual-templates. The polyurethane (PU) sponge provides an elastic structure as solid template. Meanwhile, air bubbles as gas template are used to uniformly disperse graphene oxide (GO) sheets. The burst of air bubbles in the process of thermal treatment makes GO coating on the surface of PU skeleton, avoiding the aggregation of reduced graphene oxide. Therefore, the GPCS exhibits excellent compressibility and uniform coating structure. As a result, it also possesses high sensitivity (Gauge Factor = 3.00 in the range of 0–10% strain), fast response time (35 ms), and excellent cyclic piezoresistive stability (5000 loading–unloading cycles) when applied in the pressure sensor field. Moreover, the flexible wearable stress–strain sensor assembled by the GPCS can be easily adhered on the surface of human skin and precisely detect human movements such as elbow bending and finger bending. Such low-cost procedure and excellent sensing performance enable GPCS sensor to demonstrate tremendous application potential in the field of advanced wearable devices.
        4,000원
        772.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbon (AC) is a versatile and extensively employed adsorbent in environmental remediation. It possesses distinct properties that can be enhanced to selectively target specific pollutants through modifications, including chemical impregnation or incorporation into composite materials. In this study, porous calcium alginate beads (PCAB) were synthesized by incorporating AC and natural alginate through ion gelation in a Ca(II) ion-containing solution, with the addition of sodium lauryl sulfate as a surfactant. The prepared PCAB was tested for Cu(II) removal. PCAB exhibited a spherical shape with higher porosity and surface area (160.19 m2. g−1) compared to calcium alginate beads (CAB) (0.04 m2. g−1). The adsorption kinetics followed the pseudo-first-order model for PCAB and the pseudo-second-order model for CAB. The Langmuir isotherm model provided the best fit for adsorption on PCAB, while the Freundlich model was suitable for CAB. Notably, PCAB demonstrated a maximum adsorption capacity of 75.54 mg.g−1, significantly higher than CAB's capacity of 9.16 mg. g−1. Desorption studies demonstrated that 0.1 M CaCl2 exhibited the highest efficiency (90%) in desorbing Cu(II) ions from PCAB, followed by 0.1 M HCl and 0.1 M NaCl. PCAB showed efficient reusability for up to four consecutive adsorption– desorption cycles. The fixed-bed column experiment confirmed the match with the Thomas model to the breakthrough curves with qTH of 120.12 mg.g−1 and 68.03 mg.g−1 at a flow rate of 1 mL.min−1 and 2 mL.min−1, respectively. This study indicated that PCAB could be an effective adsorbent for Cu(II) removal, offering insights for further application and design considerations.
        4,600원
        774.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sulforaphane is a naturally occurring active substance found in vegetables that is known for its potential in preventing and treating cancer. This compound has demonstrated promising effects in inhibiting the growth of various types of cancer, including esophageal, lung, colon, breast, and liver cancer. However, its instability towards pH and heat limits its application in the medical and food industries. To address this challenge, novel drug delivery systems have been developed to improve the stability and efficacy of sulforaphane, making it a more suitable candidate for clinical use in cancer research. In this study, nanocomposite materials were prepared using multi-walled carbon nanotubes (MWCNTs) and chitosan (CS) as base materials, with polydopamine (PDA) acting as a bridge material. The synthesized composite materials were used as drug carriers for the release of sulforaphane. The results of the study showed that the drug loading increased with an increase in the concentration of sulforaphane, indicating that the nanocomposite materials were effective in delivering and releasing the drug. Moreover, a positive correlation was observed between the drug loading and the thickness of the PDA layer. These findings suggest that the use of MWCNTs, CS, and PDA in the development of drug delivery systems can enhance the stability and efficacy of sulforaphane, potentially leading to improved cancer treatment outcomes.
        4,000원
        775.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The development of biocomposites using renewable resources is a cost-effective and long-term solution to environmental and resource issues. Hydrogels [Poly Sodium Acrylate (PSA)] were created by variable percentages of crosslinker concentration, and banana–cellulose microfibril (CMF) was used as a filler in this study for better reinforcement. When the concentration of crosslinker is increased, the number of covalent crosslinks increases, limiting the movement of water molecules and lowering the diffusion coefficient, equilibrium water content, the initial rate of swelling, and the theoretical equilibrium swelling ratio. The swelling behaviour of reinforced PSA with high concentrations of CMF was unexpected; the hydrophilic OH groups of CMF increase the diffusion of water molecules from the swelling medium to inside the PSA, allowing for better mechanical behaviour of gels without sacrificing the swelling response. The swelling behaviour and swelling exponent of a hydrogel were determined at various temperatures, pH levels, and physiological fluid models. The swelling exponent's maximum value was discovered to be 0.5, which suggests that the hydrogel's water diffusion was non-Fickian in nature. The swelling ratio was found to rise with rising temperature and to have a lower value than that at room temperature. It was also proven that elevating the pH of the medium from 1 to 7 improved the PSA/CMF hydrogels' swelling response. The swelling behaviour of PSA/CMF hydrogels was also investigated as the concentration of CMF rose from 0.2 to 1%. The equilibrium water content, swelling kinetics, and water transport mechanisms were all investigated. The Flory–Rehner equation was applied to determine crosslinking density, polymer mesh size, and molecular weight between crosslinks.
        4,500원
        776.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porous carbon nanofiber (CNF) electrodes for supercapacitors were prepared by using polyacrylonitrile (PAN) and cucurbituril (CB), which is a macrocyclic compound comprising glycoluril units containing hollow cores. Mixture of PAN and CB in dimethyl sulfoxide was electrospun, and thermally treated to produce CNF electrodes. Their thermal stability, surface morphology, carbon microstructures, and surface porosity were investigated. Electrochemical properties were measured using three-electrode with synthesized CNFs without further treatment as a working electrode and 1 M Na2SO4 as an electrolyte. CNFs derived from PAN and CB exhibited a high specific capacitance of 183.5 F g− 1 and an energy density of 25.4 Wh kg− 1 at 0.5 A g− 1 with stable cyclic stability during 1000 cycles, which is significantly higher than those for CNFs derived from PAN only. This demonstrated that the introduction of CB successfully improved the energy storage performance of CNF electrodes.
        4,000원
        777.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we utilized a multi-step stabilization method, incorporating dry-oxidation, to produce high-density polyethylene (HDPE)-based activated carbon fibers. This stabilization was achieved through electron-beam irradiation, sulfonation, and dry oxidation. The stabilized fibers were carbonized and activated at 900 ℃. The crystallite characteristics of the activated carbon fibers were observed using X-ray diffraction, and their surface morphologies were analyzed through scanning electron microscopy. The textural properties were analyzed using N2/ 77 K adsorption–desorption isothermal curves. And leveraging the microdomain model, we explored the influence of these stabilization methods on the HDPE-based activated carbon fibers texture properties. The results show that HDPE fibers treated with sulfonation only at 100 ℃ for 60 min were not sufficiently cross-linked and were completely decomposed during the carbonization stage. However, the sulfonated fibers treated with the new dry-oxidation process maintained their shapes and were successfully activated. The specific surface area of the resulting activated carbon fibers was as much as 2000 m2/ g.
        4,000원
        778.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The challenge of incorporating photothermal conversion function into chitosan (CS) hybrid fibers lies in balancing functionality and mechanical properties. In this study, we successfully prepared a chitosan/graphene oxide/gelatin (CS/GA/GO) hybrid fiber using the wet spinning process, achieving improved mechanical properties and efficient photothermal conversion capabilities. When compared with pure CS fiber with a breaking strength of 1.07 cN/dtex, the breaking strength of the CS/ GA composite fiber increased by 46.73%, while the CS/GA/GO hybrid fiber showed an even greater increase of 85.98%. In addition, the introduction of gelatin (GA) led to secondary scattering of near-infrared light, enhancing the photothermal conversion efficiency. As a result, the CS/GA/GO hybrid fiber exhibited a faster temperature rise rate and higher maximum temperatures (94.3 °C, 103.0 °C, and 111.3 °C) as compared to the CS/GO hybrid fiber. The successful incorporation of GA not only improved the mechanical properties but also enhanced the photothermal performance of the hybrid fiber.
        4,200원
        779.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Pitch-derived activated carbon (PAC) pellets were by steam activation for automotive carbon canisters. The crystal structure of PAC was analyzed using X-ray diffraction. The textural properties of PAC were studied by Brunauer– Emmett–Teller (BET), Horvath-Kawazoe (HK), and Non-Localized Density Functional Theory (NLDFT) equations with N2/ 77 K isotherm adsorption/ desorption curves. The butane adsorption capacity of the PAC pellets was analyzed according to the ASTM D5228 standard. With increasing steam activation time, the specific surface area and total pore volume of the PAC increased 650–1950 m2/ g and 0.27–1.02 cm3/ g, respectively. The mesopore ratio of PAC increased with increasing activation time and was observed up to 28.4% at 190 min. The butane adsorption capacity of the PAC increased and was observed to range from 10.86 to 51.55%. A close relationship between butane adsorption capacity and pore size (1.47–2.39 nm) was found. Finally, the butane activity of PAC was found to be 51.55% for the steam activated at 950 ℃ for 190 min; this butane activity is 24% better than that of the coconut-derived activated carbon (41.43%) with a similar specific surface area, indicating that pitch is a suitable material for the activated carbon of automotive carbon canisters.
        4,200원
        780.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Large-area porous carbon is easily produced for supercapacitors from polyvinylidene chloride (PVDC) and polyvinylidene fluoride (PVDF) precursors, composed of carbon backbone and attached heteroatoms. The released heteroatoms during pyrolysis leave the porous carbon. This study explored the activation of both precursors using chemical agents (ZnO, Mg(OH)2, and KOH) to develop carbon with multiple micropores and mesopores. The activation process and relevant precursors were studied to implement synthesized porous carbon as an electrode in supercapacitors. During the activation of PVDC-resin, ZnO served both as templates and activating agents, while Mg(OH)2 served only as a template, and KOH served as an activating agent. For activation of PVDF, ZnO acted as a template and activating agent, whereas Mg(OH)2 and KOH impeded activation owing to side reactions. Therefore, with the above chemical agents, PVDC-resin was converted to carbon with a higher surface area than PVDF. The porous carbon produced using PVDC-resin with KOH had the highest specific capacitance of 137 F g− 1 and rate performance of 79% at 50 mV s− 1 (vs. 5 mV s− 1) owing to the successful creation of micropores and mesopores. This study identifies optimal conditions for synthesizing porous carbon using polymer precursors and chemical agents for supercapacitors.
        4,600원