• 한국표면공학회지
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• 제54권3호
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• pp.144-151
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• 2021

In the present work, planar-type ZnO powder of [0001] plane with a high aspect ratio range of 20:1 to 50:1 was synthesized. Ag or CuO could be coated on the planar-type ZnO powder by wet methods such as centrifugation or ball milling. During the coating, the average size of the powder was slightly increased while maintaining the shape and XRD pattern of ZnO. When Ag or CuO was coated, the absolute value of the zeta potential, as well as the concentration of oxygen vacancy, was increased. Ag or CuO coated planar-type ZnO power exhibited excellent antibacterial performance, which seems to be related to their high electrostatic attraction force. They could be made into a masterbatch by mixing with ABS resin, and their applicability to antibacterial substances was confirmed by manufacturing the caps of a keyboard.

• 한국분말재료학회지
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• 제28권6호
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• pp.470-477
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• 2021

Energy storage systems should address issues such as power fluctuations and rapid charge-discharge; to meet this requirement, CoFe₂O₄ (CFO) spinel nanoparticles with a suitable electrical conductivity and various redox states are synthesized and used as electrode materials for supercapacitors. In particular, CFO electrodes combined with carbon nanofibers (CNFs) can provide long-term cycling stability by fabricating binder-free three-dimensional electrodes. In this study, CFO-decorated CNFs are prepared by electrospinning and a low-cost hydrothermal method. The effects of heat treatment, such as the activation of CNFs (ACNFs) and calcination of CFO-decorated CNFs (C-CFO/ACNFs), are investigated. The C-CFO/ACNF electrode exhibits a high specific capacitance of 142.9 F/g at a scan rate of 5 mV/s and superior rate capability of 77.6% capacitance retention at a high scan rate of 500 mV/s. This electrode also achieves the lowest charge transfer resistance of 0.0063 Ω and excellent cycling stability (93.5% retention after 5,000 cycles) because of the improved ion conductivity by pathway formation and structural stability. The results of our work are expected to open a new route for manufacturing hybrid capacitor electrodes containing the C-CFO/ACNF electrode that can be easily prepared with a low-cost and simple process with enhanced electrochemical performance.

• 공업화학
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• 제34권1호
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• pp.57-63
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• 2023

본 연구에서는 Abaca 나노 셀룰로오스와 이산화 티타늄(TiO₂)의 유-무기 하이브리드 복합체를 제조하였다. Abaca 나노 셀룰로오스는 Abaca 셀룰로오스를 산화시키는 방법으로 제조하였으며, 촉매로서 TEMPO (2,2,6,6-tetramethyl-piperidine-1-oxyl)를 이용하였다. TiO₂ 나노입자는 sol-gel법으로 제조하였으며 이를 나노 셀룰로오스와 하이브리드(hybrid) 시켜 복합체를 제조하였다. 제조 pH 변화에 따른 복합체의 특성과 그의 물성을 비교해 본 결과, 나노 셀룰로오스와 이산화 티타늄 결합 시 pH의 영향이 매우 컸으며, 본 실험 조건에서 pH 8에서 최적의 결합성능을 나타냈다. 또한, 제조된 복합체는 광촉매 특성을 보였으며, 이산화 티타늄의 함량이 높을수록 UV광 조사에 따라 복합체의 친수성이 증가하였다.

• Design & Manufacturing
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• 제16권4호
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• pp.52-59
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• 2022

Currently, Korea is an aging society and is expected to become a super-aged society in about four years. X-ray devices are widely used for early diagnosis in hospitals, and many X-ray technologies are being developed. The development of X-ray device technology is important, but it is also important to increase the reliability of the device through accurate data management. Sensor nodes such as temperature, voltage, and current of the diagnosis device may malfunction or transmit inaccurate data due to various causes such as failure or power outage. Therefore, in this study, the temperature, tube voltage, and tube current data related to each sensor and detection circuit of the diagnostic X-ray imaging device were measured and analyzed. Based on QC data, device failure prediction and diagnosis algorithms were designed and performed. The fault diagnosis algorithm can configure a simulator capable of setting user parameter values, displaying sensor output graphs, and displaying signs of sensor abnormalities, and can check the detection results when each sensor is operating normally and when the sensor is abnormal. It is judged that efficient device management and diagnosis is possible because it monitors abnormal data values (temperature, voltage, current) in real time and automatically diagnoses failures by feeding back the abnormal values detected at each stage. Although this algorithm cannot predict all failures related to temperature, voltage, and current of diagnostic X-ray imaging devices, it can detect temperature rise, bouncing values, device physical limits, input/output values, and radiation-related anomalies. exposure. If a value exceeding the maximum variation value of each data occurs, it is judged that it will be possible to check and respond in preparation for device failure. If a device's sensor fails, unexpected accidents may occur, increasing costs and risks, and regular maintenance cannot cope with all errors or failures. Therefore, since real-time maintenance through continuous data monitoring is possible, reliability improvement, maintenance cost reduction, and efficient management of equipment are expected to be possible.

• 한국결정성장학회지
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• 제33권4호
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• pp.139-144
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• 2023

무기충진제와 가소성 폴리머로 이루어진 스톤페이퍼는 기존 종이의 원료인 펄프를 사용하지 않아 자연보존에 기여하고 생분해성을 가지게 되면 보다 친환경적인 소재로 사용이 가능하다. 현재 대부분의 스톤페이퍼는 가열압출성형법으로 제조하고 있어 작업성을 증진시키기 위해 세라믹 충진제의 양이 제한되어 다양한 물성을 가질 수 없다. 본 연구에서는 이러한 스톤페이퍼 조성을 용제를 사용한 액상으로 제조하게 됨으로써 세라믹 충진제 첨가량에 제한이 적고 생분해성 조절을 위한 첨가제 투입도 용이하였다. 폐패각인 굴껍질을 열처리하여 무기충진제로 사용하였고, 재활용 소재로도 쉽게 구할 수 있는 폴리비닐클로라이드를 유기결합제로 사용하였다. 일반적인 폴리비닐클로라이드용 유기용제를 사용하여 폴리비닐클로라이드를 용해시킨 후 무기충진제와 생분해성을 부여하기 위한 셀룰로스를 혼합하여 시트 형태로 가공하여 용제기반 스톤페이퍼를 제조하여 그 물성에 대해 분석하였다.

• 한국항공우주학회지
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• 제50권4호
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• pp.277-285
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• 2022

뉴스페이스 시대를 대표하는 소형위성 분야에서 발사기회에 대한 수요가 크게 증가하고 있다. 이를 위한 소형위성 전용 발사서비스를 합리적인 가격에 제공하는 것은 많은 스타트업 기업들이 추구하는 새로운 비즈니스 모델이 되고 있으며, 여기에는 저비용 부품과 대량생산, 최적화된 제작 공정이 결합된 비용 절감을 위한 혁신적인 솔루션들이 요구되고 있다. 이러한 흐름 속에서 우리나라에서도 한국항공우연구원에서 제3차 우주개발 진흥 기본계획에 따라 누리호를 통해 개발된 액체로켓엔진 기술을 기반으로 2단형 소형발사체 개발에 대비하여 핵심기술 및 비용절감 기술들을 개발하기 위한 선행기술 연구에 착수하였다. 본 논문에서는 소형위성을 위한 혁신적이며 가격 경쟁력을 가지는 것을 목표로 하는 2단형 소형발사체의 개념을 소개하고, 스테이징 설계 및 2단형 발사체의 전기체 구성안을 포함한 임무설계 결과를 기술하였다.

• Advances in nano research
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• 제14권5호
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• pp.435-442
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• 2023

Sports activities, including playing tennis, are popular with many people. As this industry has become more professionalized, investors and those involved in sports are sure to pay attention to any tool that improves athletes' performance Tennis requires perfect coordination between hands, eyes, and the whole body. Consequently, to perform long-term sports, athletes must have enough muscle strength, flexibility, and endurance. Tennis rackets with new frames were manufactured because tennis players' performance depends on their rackets. These rackets are distinguished by their lighter weight. Composite rackets are available in many types, most of which are made from the latest composite materials. During physical exercise with a tennis racket, nanocomposite materials have a significant effect on reducing injuries. Materials as strong as graphite and thermoplastic can be used to produce these composites that include both fiber and filament. Polyamide is a thermoplastic typically used in composites as a matrix. In today's manufacturing process, materials are made more flexible, structurally more vital, and lighter. This paper discusses the production, testing, and structural analysis of a new polyamide/Multi-walled carbon nanotube nanocomposite. This polyamide can be a suitable substitute for other composite materials in the tennis racket frame. By compression polymerization, polyamide was synthesized. The functionalization of Multi-walled carbon nanotube (MWCNT) was achieved using sulfuric acid and nitric acid, followed by ultrasonic preparation of nanocomposite materials with weight percentages of 5, 10, and 15. Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) confirmed a synthesized nanocomposite structure. Nanocomposites were tested for thermal resistance using the simultaneous thermal analysis (DTA-TG) method. scanning electron microscopy (SEM) analysis was used to determine pores' size, structure, and surface area. An X-ray diffraction analysis (XRD) analysis was used to determine their amorphous nature.

• 한국식생활문화학회지
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• 제25권6호
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• pp.680-707
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• 2010

Research was conducted on vinegar types and characteristics with reference to representative literature such as SanGaYoRok, SikRyoChanYo, SooEunJabBang, GoSaChalYo, DongEuiBoGam, SaSiChanYoCho, JuBangMoon, ShinGanGuWhang, ChalYoSeo, EumSikDiMiBang, YoRok, ChiSengYoRam, SanRimKyoungJae,EumSikBo,OnJuBeop, SulManDeuNunBeop, KyuHapChongSeo, ImWonSipYukJi, JungIlDangJabJi, SulBitNeunBeop, SiUiJeonSeo, and BuInPilJi from the 15th to the 19th centuries of the Joseon Dynasty. Based on this research, a classification of materials used in vinegar, knowledge on treatment, preparation of ingredients, capturing flavor, storage of vinegar, as well as the favorable days that vinegar can be manufactured were studied and analyzed based on the different aspect of vinegar. Vinegar is a wellknown condiment throughout the world and has the potential of becoming a luxurious food. Replication and further analysis to expand the properties of vinegar is necessary using old literature, together with the literature identified above. Based on ongoing research, it is foreseeable that the development of a vinegar with unique characteristics and improved standards will be the foundation for the globalization of Korean cuisine, which is our current focus.

• 미래기술융합논문지
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• 제3권2호
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• pp.39-44
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• 2024

본 연구는 현대인의 스트레스로 인한 우울증, 불안, 불면증을 개선할 목적으로 천연 아로마 솔루션을 개발하고, 그 솔루션을 이용하여 물티슈에 응용하였다. 구체적으로, 소나무오일 솔루션는 한국산 소나무 오일과 블랙체리 오일를 혼합하여 제조하였다. 제조한 소나무 오일 솔루션에 대하여, 중금속 분석, 항균 분석, 심리 평가 및 피부 평가를 수행하고 스트레스 개선용 기능성 아로마 물티슈 제조 가능성을 검토하였다. 더나아가, 소나무오일 솔루션 물티슈의 피부 개선 여부를 조사한 결과, 보습 및 탄력 측면에서 개선의 효과가 있는 것으로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권5호
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• pp.1273-1300
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• 2024

In the complex virtual environment of cyberspace, comprised of digital and communication networks, ensuring the security of information is being recognized as an ongoing challenge. The importance of 'Cyber Situation Awareness (CSA)' is being emphasized in response to this. CSA is understood as a vital capability to identify, understand, and respond to various cyber threats and is positioned at the heart of cyber security strategies from a defensive perspective. Critical industries such as finance, healthcare, manufacturing, telecommunications, transportation, and energy can be subjected to not just economic and societal losses from cyber threats but, in severe cases, national losses. Consequently, the importance of CSA is being accentuated and research activities are being vigorously undertaken. A systematic five-step approach to CSA is introduced against this backdrop, and a deep analysis of recent research trends, techniques, challenges, and future directions since 2019 is provided. The approach encompasses current situation and identification awareness, the impact of attacks and vulnerability assessment, the evolution of situations and tracking of actor behaviors, root cause and forensic analysis, and future scenarios and threat predictions. Through this survey, readers will be deepened in their understanding of the fundamental importance and practical applications of CSA, and their insights into research and applications in this field will be enhanced. This survey is expected to serve as a useful guide and reference for researchers and experts particularly interested in CSA research and applications.