Daegu Gyeongbuk Institute of Science and Technology
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Revolutionizing waste-to-energy: harnessing the power of triboelectric nanogenerators
No full textRecently, there has been a lot of focus on developing new waste-to-energy technologies because they help us to provide sustainable energy solutions for future generations. This review paper investigates an innovative waste-to-energy technology known as triboelectric nanogenerators (TENGs), which uses the electrostatic induction and contact electrification principles of physics. The underlying physics of TENG technology allows for a wide range of material choices for its fabrication; as a result, waste materials are utilized for energy production using TENGs. It comprehensively discusses how various types of waste, including plastic, electronic, medical, household, and biowaste, can be integrated into TENG technology for efficient energy production. Furthermore, various applications of waste-based TENGs are discussed in detail. Finally, we projected challenges and future directions for creating a sustainable, green energy landscape. Graphical abstract: The review article presents a detailed exploration of triboelectric nanogenerators (TENGs) as novel waste-to-energy technologies that utilize waste materials. (Figure presented.) © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.FALSEsciescopu
PEDAL SIMULATOR
No full text페달 시뮬레이터가 개시된다. 본 페달 시뮬레이터는, 페달, 페달의 스트로크에 연동되어 전진 또는 후진하는 플레이트, 플레이트와 대향 배치되는 하우징, 하우징에 고정되는 전단 및 플레이트의 전면에 접하는 후단을 포함하는 제1 탄성 부재 및 하우징에 고정되는 전단 및 제1 탄성 부재보다 전방에 배치되어 플레이트를 바라보는 후단을 포함하는 제2 탄성 부재를 포함한다
ULTRASOUND ENDOSCOPIC SYSTEM
No full text본 발명은, 초음파 내시경 시스템에 관한 것이다. 이러한 초음파 내시경 시스템은, 캡슐 초음파 프로브로부터 송신되는 서로 다른 주파수를 가지는 초음파 신호를 인공지능 네트워크가 수신하여 고해상도 초음파 영상 및 저해상도 초음파 영상을 생성하고, 생성된 고해상도 초음파 영상 및 저해상도 초음파 영상을 학습하여 이를 기초로 소정 조직의 다양한 깊이에 관한 정보를 포함하면서도 높은 해상도를 가지는 초음파 영상을 출력한다
Magnesium Ions Storage in Molybdenum Oxide Structures Examined as a Promising Cathode Material for Rechargeable Magnesium Batteries
Get PDFMagnesium batteries have attracted considerable attention as a promising technology for future energy storage because of their capability to undergo multiple charging reactions. However, most oxide materials utilized as hosts for magnesium batteries do not perform well at room temperature or in nonaqueous electrolytes. Herein, a host material, Na0.04MoO3·(H2O)0.49 is successfully developed through the chemical reduction of alpha-MoO3, which enables magnesium storage reaction in a 0.5 m Mg(ClO4)2/acetonitrile electrolyte at 25 °C. Electrochemical analysis reveals that the cathode material possesses a discharge capacity of 157.4 mAh g−1 at a 0.2 C rate. The Na0.04MoO3·(H2O)0.49 cathode material also exhibits a capacity retention of 93.4% after 100 cycles compared to the first cycle at a 2 C rate, with an average discharge voltage of −0.474 V versus activated carbon (≈2.16 V estimated discharge voltage vs Mg/Mg2+). The study findings demonstrate, for the first time, the potential of this material as a cathode for magnesium batteries at ambient temperatures and in nonaqueous electrolytes. © 2023 The Authors. Small Structures published by Wiley-VCH GmbH.TRUEsci
Properties of Si-AlN Core-Shell Microcrystals by Al-Based Nanostructures
Get PDF육방정계 (hexagonal) Si-AlN 코어-쉘 (core-shell) 마이크로 결정을 혼합소스 수소화물기상법에 의해 성장하였다. 특히 육방정계 Si-AlN 코어-쉘 마이크로 결정은 Al 기반 나노구조 (Al-based nanostructure)를 기반으로 성장되는 것을 발견하였다. 육방정계 Si은 준 직접 밴드갭 (quasi-direct bandgap) 에너지를 가지며 AlN 또한 육각형 우르자이트 (wurtzite) 구조를 가지므로 전력반도체 혹은 광전소자에 대한 새로운 기회를 열 수 있다. 본 논문에서 성장된 육방정계 Si-AlN 코어-쉘 마이크로 결정은 주사전자현미경 (FE-SEM), EDS, 및 HRTEM을 사용하여 그 특성을 확인하였으며 성장 메커니즘을 제시한다. 따라서 육방정계 Si-AlN 코어-쉘 마이크로 결정은 반도체 성장 방법의 새로운 예가 될 것으로 기대한다.
Hexagonal Si-AlN core-shell microcrystals were grown by the mixed-source hydride vapor phase method. In particular, it was found that the hexagonal Si-AlN core-shell microcrystals were grown by the role of the Al-based nanostructure. Since hexagonal Si has a quasi-direct bandgap energy and AlN also has a hexagonal wurtzite structure, it can open up new opportunities for power semiconductors or optoelectronic devices. In this paper, the hexagonal Si-AlN core-shell microcrystals grown were characterized using scanning electron microscopy (FE-SEM), EDS and HRTEM, and the growth mechanism is presented. Therefore, the hexagonal Si-AlN core-shell microcrystal is expected to be an example of a new method in the field of semiconductor growth. © New Physics: Sae Mulli.TRUEscopuskc
The Role of the Bottom Oxide Layer in Oxide-Metal-Oxide (OMO) Electrode for Stretchable Organic Light-Emitting Diodes
Get PDFThe challenges for stretchable organic light-emitting diodes (SOLEDs) have led research into advanced manufacturing processes. Several electrodes have been researched to replace conventional indium tin oxide in SOLEDs due to its brittleness, indium scarcity in earth, and poor deformation capabilities. Oxide–metal–oxide (OMO) electrodes are promising alternatives for flexible/stretchable electronics owing their excellent charge injection and optical transparencies, including mechanical compliance. In this study, two oxides (i.e., MoO3 and V2O5) with different surface energies in an OMO structure to effectively inhibit the island growth of the ultra-thin Au (5nm) metal is incorporated. The morphology and interfacial coordinate covalent bonds between the seed layer and ultra-thin Au film are extensively studied. The improved ultra-thin Au growth in OMO structure together with figure-of-merit have been employed as the anode for a phosphorescent SOLED structure. The SOLEDs with OMO electrode under V2O5 as bottom oxide remain stable after peeling-off and sustain a >50% uniaxial strain with a negligible reduction in luminance and current efficiencies. The surface energy and interface of the bottom oxide in the OMO structure are crucial for thin metals to attain superior optical, structural, electronic, and mechanical stability in SOLEDs. © 2023 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.TRUEsciescopu
Surface-modified Ag@Ru-P25 for photocatalytic CO2 conversion with high selectivity over CH4 formation at the solid–gas interface
Get PDFSystematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO2 reduction to solar fuels. A surface-modified Ag@Ru-P25 photocatalyst with H2O2 treatment was designed in this study to convert CO2 and H2O vapor into highly selective CH4. Ru doping followed by Ag nanoparticles (NPs) cocatalyst deposition on P25 (TiO2) enhances visible light absorption and charge separation, whereas H2O2 treatment modifies the surface of the photocatalyst with hydroxyl (–OH) groups and promotes CO2 adsorption. High-resonance transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, and extended X-ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst, while thermogravimetric analysis, CO2 adsorption isotherm, and temperature programmed desorption study were performed to examine the significance of H2O2 treatment in increasing CO2 reduction activity. The optimized [email protected] photocatalyst performed excellent CO2 reduction activity into CO, CH4, and C2H6 with a ~95% selectivity of CH4, where the activity was ~135 times higher than that of pristine TiO2 (P25). For the first time, this work explored the effect of H2O2 treatment on the photocatalyst that dramatically increases CO2 reduction activity. © 2023 The Authors. Carbon Energy published by Wenzhou University and John Wiley & Sons Australia, Ltd.TRUEsciescopu
Precoding Design for Ensuring Data Freshness in Multi-user MISO Networks
No full textThe existing multiple-input single-output (MISO) design to transmit data reliably to multiple mobile users (MUs) has become insufficient as MUs require fresh data, not just data. Therefore, in this paper, we consider multi-user MISO networks, where a base station (BS) equipped with multiple antennas serves MUs that want to maintain data freshness. To analyze the data freshness in this network, we first define the age-of-information (AoI) violation ratio, which is the ratio of duration that the AoI is larger than the AoI violation threshold to a sensing period. We then obtain the upper bound on the AoI violation ratio using the smooth maximum/minimum unit. We consider an optimization problem that minimizes the AoI violation ratio of multiple MUs. We propose a generalized power iteration (GPI) precoding algorithm to find a principal precoding vector that satisfies a first-order optimality condition of the optimization problem. Furthermore, for the scenario where the BS has the imperfect channel state information (CSI) of MUs, we provide the upper bound on the AoI violation time using the lower bound on the ergodic spectral efficiency, and also design the GPI precoding algorithm. Simulation results show proposed methods outperform baseline methods and demonstrate the effect of network parameters on the AoI violation probability. © 2023 IEEEFALSEsciescopu
Lactoferrin-polyphenol composite nanocoating with enhanced chemical stability and cell-compatibility
No full textLactoferrin is a functional whey protein that exhibits beneficial bioactivities to human health. To utilize the wide range of lactoferrin's biomedical advantages, much effort has been devoted to developing lactoferrin coating strategies. However, lactoferrin coating has been still limited to the conventional protein modification techniques, which hamper the practical applications of lactoferrin. Here, we demonstrate lactoferrin composite nanocoating by layer-by-layer assembly with lactoferrin and Fe(III)-tannic acid complex. The simple immersive processes are able to deposit lactoferrin composite nanolayers on planar substrates with precise thickness tuneablility. Also, the optimized deposition condition for lactoferrin composite nanocoating is applicable to particulate substrates. Further, lactoferrin composite nanocoating shows enhanced nanofilm stability against pH changes and digestive enzyme treatments, and improves cell compatibility greatly, compared to that of Fe(III)-TA complex. We envisage that lactoferrin composite nanocoating not only paves the way for exploiting full potential of lactoferrin's bioactivities, but also leads to stimulating the tailored design of composite nanomaterials containing multiple enzymes for customized applications in nanomedicine and nanobiosensor. © 2023FALSEsciescopu
Mangifera indica stone-assisted layered double hydroxide biocomposites: efficient contenders for reactive dye adsorption from aqueous sources
No full textHerein, magnesium-aluminum layered double hydroxides (Mg-Al-LDH) were synthesized by an environmentally friendly and economically promising hydrothermal technique for the adsorption of the dye reactive green 5 (RG5). To further enhance the RG5 dye adsorption capability of Mg-Al-LDH, their composites were designed by using low-cost Mangifera indica stone biomass (MISB). From their physiochemical properties evaluated by scanning electron microscopy and Fourier transform infrared spectroscopy, they were found to display an irregular morphology along with the existence of various functional groups (including OH, C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O, and C-H) on surfaces, enabling prepared biosorbents to be excellent candidates for adsorption. Batch adsorption trials were conducted to determine the comparative RG5 dye adsorption efficiencies of MISB, Mg-Al-LDH and the Mg-Al-LDH@MISB composite in an aqueous medium. The highest RG5 dye adsorption capacities recorded under optimized conditions (contact time: 90 min, pH: 3, adsorbent dosage: 0.05 g, initial RG5 dye concentration: 80 mg L−1 and temperature: 30 °C) for MISB, Mg-Al-LDH and the Mg-Al-LDH@MISB composite were 55.9 mg g−1, 68.4 mg g−1 and 73.5 mg g−1, respectively. The kinetic and isothermal study showed the best fit of the pseudo 2nd order and Freundlich models. Thermodynamic parameters illustrated the spontaneity of the process. In addition, the adsorbents as designed also possessed regeneration capability as evidenced by their RG5 dye desorption potential. Therefore, this research opens up new doors for the development of environmentally friendly Mg-Al-LDH by developing composites with economically feasible biomass for industrial wastewater treatment. © 2024 The Royal Society of ChemistryFALSEsciescopu