• 한국지반신소재학회논문집
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• 제22권4호
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• pp.1-8
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• 2023

우주 탐사는 인류의 과학적 노력 중 가장 선두에 있으며, 행성 탐사 로버는 행성 지표면을 연구하는 핵심 장비이다. 행성 로버의 성능은 가파른 경사와 다양한 행성 지형을 탐지하고 통과하는 데 큰 영향을 미치며 특히 달과 같은 행성에서는 급격한 경사와 연약한 지면을 안전하게 등반하고 이동할 수 있는 능력이 필수적으로 요구된다. 이 논문에서는 우주 행성 탐사 로버가 직면하는 가파른 지형과 연약한 지면을 모사하는 등반 시험장의 설계와 검증 방법을 종합적으로 소개한다. 먼저 달의 크레이터 지역의 지형 특성과 탐사의 중요성을 간략히 설명하고, 기존 등반 시험장의 개발 사례를 살펴보며, 현재 한국건설기술연구원에서 운영 중인 지반열진공챔버 내에 설치 예정인 등반 시험장의 설계 과정을 설명한다. 본 연구에서 제안하는 등반 시험장이 개발되면 실제 달의 환경과 유사한 고진공, 극한 온도 조건에서 로버의 이동과 탐사 능력을 정밀하게 평가할 수 있을 것으로 기대된다.

• 패션비즈니스
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• 제27권5호
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• pp.93-107
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• 2023

This study aimed to design a knee brace with dry electrode EMS (Electrical Muscle Stimulation) for elite badminton players suffering from knee pain and assess its effectiveness in relieving pain and improving mobility. The assessment measured knee joint range of motion (ROM), Sargent jump height, and pain perception using a visual analog scale (VAS). Four experimental groups were established: stability, pain induction after 100 squats, muscle soreness induction with a regular knee brace, and muscle soreness induction with the EMS knee brace. The most suitable knee brace was selected from four samples to design the EMS knee brace. The conductive fabric was integrated into the inner surface of the knee brace to enhance EMS conductivity for the quadriceps muscles. Tensile strength tests showed that the dry electrode did not significantly affect the physical functionality of the knee brace.Regarding knee joint ROM and Sargent jump height, the EMS knee brace outperformed muscle soreness induction with a regular knee brace and wearing a standard knee brace. VAS measurements demonstrated that the EMS braces effectively alleviated pain perception in most cases. The results indicate the potential for developing EMS braces to alleviate pain and prevent injuries for athletes across various sports.

• 마이크로전자및패키징학회지
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• 제29권4호
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• pp.49-53
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• 2022

본 연구는 최적화된 전기발광 성능을 가진 양자점 전계 발광 다이오드 소자를 제작하기 위해 RF sputtering 기법으로 Zn_0.85Mg_0.15O 박막을 전자수송층으로 적용하였다. 일반적으로 양자점 전계 발광 다이오드에서 ZnO 나노입자는 적절한 에너지 준위를 가지고 있어 전자 이동도가 빠르고 용액 처리가 용이하다는 장점으로 전자 수송층으로 널리 사용되는 재료이다. 그러나, 용액형 ZnO 나노입자의 불안정성 문제는 아직 해결되지 않고 있다. 이를 해결하기 위해 본 연구에서는 ZnO에 15 % Mg을 도핑한 ZnMgO 박막을 RF sputtering법으로 제작하고 전자수송층으로 적용한 소자를 최적화하였다. 최적화된 ZnMgO 박막을 이용한 소자는 최대 휘도 15,972 cd/m², 전류효율 7.9 cd/A를 보였다. Sputtering ZnMgO 박막 기반 양자점 전계 발광 다이오드 소자는 용액형 ZnO 나노입자의 문제를 해결하고 미래 디스플레이 소자 제작 기술의 적용 가능성을 확인하였다.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1171-1181
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• 2023

In this study, a sweep gas - vacuum hybrid type membrane degassing process was proposed for ammonia wastewater treatment. In addition, the ammonia selective recovery of the hybrid type membrane degassing process was also investigated. As a result, the hybrid type membrane degassing process showed better degassing performance (54.9 mg NH₃/m²min for 360 min) than the sweep gas type (32.3 mg NH₃/m²min) or vacuum type (22 mg NH₃/m²min). Additionally, the hybrid type membrane degassing process showed an excellent ammonia selectivity (103 times compared to Na+ Na⁺, 133 times compared to Ca²⁺). The ammonia selectivity was appeared to be due to the conversion characteristics of ammonium ion / dissolved ammonia depending on pH. The results in this study are expected to be used in the development of ammonia wastewater treatment and ammonia recovery in the future.

• Hip & pelvis
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• 제35권2호
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• pp.122-132
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• 2023

Purpose: The dome technique is a technique used in performance of revision total hip arthroplasty (THA) involving intraoperative joining of two porous metal acetabular augments to fill a massive anterosuperior medial acetabular bone defect. While excellent outcomes were achieved using this surgical technique in a series of three cases, short-term results have not been reported. We hypothesized that excellent short-term clinical and patient reported outcomes could be achieved with use of the dome technique. Materials and Methods: A multicenter case series was conducted for evaluation of patients who underwent revision THA using the dome technique for management of Paprosky 3B anterosuperior medial acetabular bone loss from 2013-2019 with a minimum clinical follow-up period of two years. Twelve cases in 12 patients were identified. Baseline demographics, intraoperative variables, surgical outcomes, and patient reported outcomes were acquired. Results: The implant survivorship was 91% with component failure requiring re-revision in only one patient at a mean follow-up period of 36.2 months (range, 24-72 months). Three patients (25.0%) experienced complications, including re-revision for component failure, inter-prosthetic dual-mobility dissociation, and periprosthetic joint infection. Of seven patients who completed the HOOS, JR (hip disability and osteoarthritis outcome score, joint replacement) survey, five patients showed improvement. Conclusion: Excellent outcomes can be achieved using the dome technique for management of massive anterosuperior medial acetabular defects in revision THA with survivorship of 91% at a mean follow-up period of three years. Conduct of future studies will be required in order to evaluate mid- to long-term outcomes for this technique.

• Physical Therapy Rehabilitation Science
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• 제13권1호
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• pp.43-52
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• 2024

Objective: This study aimed to investigate the impact of a 12-week combined cognitive and physical exercise program on cognitive and physical functions in older adults diagnosed with mild cognitive impairment (MCI). Design: A one-group pretest-posttest study. Methods: Twelve participants with MCI engaged in a weekly 60-minute session of combined cognitive and physical exercise program. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), while physical function was evaluated through measures of muscle strength, postural balance, and walking capabilities. Muscle strength assessments included the arm curl test, handgrip strength, and the 5 sit-to-stand test. Postural balance was evaluated using the one-leg stance test, timed up-and-go test, functional reach test, and four square step test. Walking function was analyzed through a gait analysis device. Pre- and post-intervention measurements were compared to determine the effects of the exercise program. Results: The results demonstrated significant improvements in MoCA, arm curl test, timed up-and-go test, walking speed, and cadence following the 12-week intervention (p<0.05). MoCA scores revealed enhanced cognitive performance, while measures of muscle strength, including the arm curl test, exhibited significant changes. Improvements in timed up-and-go test scores indicated enhanced mobility, accompanied by increased walking speed and cadence, as evidenced by gait analysis. Conclusions: This study suggests that a structured 12-week program incorporating both cognitive and physical exercises can lead to meaningful improvements in cognitive and physical functions among older adults with MCI.

• 전기전자학회논문지
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• 제28권1호
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• pp.33-37
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• 2024

본 논문에서는 0.25 ㎛ 게이트 길이를 갖는 GaN HEMT 기술을 사용하여 개발한 X-대역 저잡음 증폭기 MMIC의 특성을 기술한다. 개발된 GaN 기반 X-대역 저잡음 증폭기 MMIC는 9 GHz ~ 10 GHz의 동작 주파수 대역에서 22.75 dB ~ 25.14 dB의 소신호 이득과 1.84 dB ~ 1.94 dB의 잡음지수 특성을 나타내었다. 입력 반사 손실 특성과 출력 반사 손실 특성은 각각 -11.36 dB ~ -24.49 dB, -11.11 dB ~ -17.68 dB를 얻었으며 40 dBm (10 W)의 입력 전력에 성능 열화 없이 정상적으로 동작하였다. MMIC의 크기는 3.67 mm × 1.15 mm이다. 개발된 GaN 기반 저잡음 증폭기 MMIC는 X-대역의 다양한 응용에 적용 가능하다.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.400-406
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• 2024

Next-generation wide-bandgap semiconductors such as SiC, GaN, and Ga2O3 are being considered as potential replacements for current silicon-based power devices due to their high mobility, larger size, and production of high-quality wafers at a moderate cost. In this study, we investigate the gradual modulation of chemical composition in multi-stacked metal oxide semiconductor thin films to enhance the performance and bias stability of thin-film transistors (TFTs). It demonstrates that adjusting the Ga ratio in the indium gallium oxide (IGO) semiconductor allows for precise control over the threshold voltage and enhances device stability. Moreover, employing multiple deposition techniques addresses the inherent limitations of solution-processed amorphous oxide semiconductor TFTs by mitigating porosity induced by solvent evaporation. It is anticipated that solution-processed indium gallium oxide (IGO) semiconductors, with a Ga ratio exceeding 50%, can be utilized in the production of oxide semiconductors with wide band gaps. These materials hold promise for power electronic applications necessitating high voltage and current capabilities.

• 센서학회지
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• 제33권4호
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• pp.224-229
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• 2024

Quantum dot light-emitting diodes (QD-LEDs) are emerging as next-generation displays owing to their high color purity, wide color gamut, and solution processability. Enhancing the efficiency of QD-LEDs involves preventing non-radiative recombination mechanisms, such as Auger and interfacial recombination. Generally, ZnO serves as the electron transport layer, which is known for its higher mobility compared to that of organic semiconductors and can lead to excessive electron injection. Some of the injected electrons pass through the quantum dot emissive layer and undergo non-radiative recombination near or within the organic hole transport layer (HTL), resulting in HTL degradation. Therefore, the implementation of electron blocking layers (EBLs) is essential; however, studies on all-solution-processed inverted InP QD-LEDs are limited. In this study, poly(9-vinylcarbazole) (PVK) is introduced as an EBL to mitigate HTL degradation and enhance the emission efficiency of inverted InP QD-LEDs. Using a single-carrier device, PVK was confirmed to effectively inhibit electron overflow into the HTL, even at extremely low thicknesses. The optimization of the PVK thickness also ensured minimal disruption of the hole-injection properties. Consequently, a 1.5-fold increase in the maximum luminance was achieved in the all-solution-processed inverted InP QD-LEDs with the EBL.

• 한국국방기술학회 논문지
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• 제5권2호
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• pp.17-22
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• 2023

4차 산업혁명 기반의 무인화 및 인공지능 기술의 발전 속에 대한민국 육군은 미래첨단과학기술이 집약된 지상전투체계 ARMY TIGER 4.0을 추진 중이다. 이 체계는 AI 기반 초연결 지상전투체계를 중심으로 발전해나가고 있으며, 기동화, 지능화, 네트워크화를 핵심개념으로 한다. 이중 드론봇 전투체계는 기존의 드론과 로봇의 합성어로 무인전투체계를 포괄적으로 지칭한다. 이러한 추세 속에, 미래 전장은 무인화 및 인공지능 기반의 무기체계 활용이 증대될 것으로 예상된다. 특히 무인화로 전환하는 과도기에는 개별 무인체계 혹은 유·무인체계간 연결성을 보장하는 것이 상당히 중요한 문제이다. 본 논문에서는 효과적인 지휘통제 및 통신을 위한 Multiplexer 할당문제(MAP)를 소개하고, 수학적 모형을 제시함과 동시에 즉응적으로 모형의 해를 도출해줄 수 있는 휴리스틱 알고리즘을 제안한다. 또한, 해당 MAP 모형의 최적해를 도출하여, 본 논문에서 제안한 휴리스틱 알고리즘의 해의 품질과 계산시간을 제시한다. 추가적으로, MAP에 대한 향후 연구방향에 대해서도 논의한다.