• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2531-2536
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• 2010

Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been employed to investigate the molecular structures and absorption spectra of two dyes containing diphenylaniline and 4-diphenylamino-diphenylaniline as donor moiety (TPA1 and TPA3). The geometries indicate that the strong conjugation is formed in the dyes. The electronic structures suggest that the intramolecular charge transfer from the donor to the acceptor occurs, and the electron-donating capability of 4-diphenylamino-diphenylaniline is stronger than that of diphenylaniline. The computed highest occupied molecular orbital (HOMO) energy levels are -5.31 and -4.90 eV, while the lowest unoccupied molecular orbital (LUMO) energies are -2.29 and -2.26 eV for TPA1 and TPA3, respectively, revealing that the interfacial charge transfer between the dyes and the semiconductor electrode are electron injection processes from the photon-excited dyes to the semiconductor conduction band. Furthermore, all the experimental absorption bands of TPA1 and TPA3 have been assigned according to the TDDFT calculations.

• 전기학회논문지
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• 제66권7호
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• pp.1141-1148
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• 2017

Generally, a thermistor made by sintering a metal oxide is widely used to measure the ambient temperature. This thermistor is widely used not only for industrial use but also for medical use because of its excellent sensitivity, durability, temperature change characteristics and low cost. In particular, the normal body temperature is 36.9 degrees relative to the armpit temperature, and it is most closely related to the circulating blood flow. Previous studies have shown that body temperature changes during biomechanical changes and body temperature changes by anomalous signs or illnesses. Therefore, in this study, we propose a Lock-In-Amp design to detect minute temperature changes of clothing and thermistor wired by a preacher as a method to regularly measure body temperature in daily life. Especially, it is designed to measure the minute resistance change of the thermistor according to body temperature change even in a low-cost microprocessor environment by using a micro-processor-based Lock-In-Amp, and a jacquard and the thermistor is arranged so as to be close to the side, so that the reference body temperature can be easily measured. The temperature was measured and stored in real time using short-range wireless communication for non - restraint temperature monitoring. A baby vest was made to verify its performance through temperature experiments for infants. The measurement of infant body temperature through the existing skin sensor or thermometer has limitations in monitoring infant body temperature for a long time without restriction. However, it can be overcome by using the embroidery fabric based micro temperature monitoring wireless monitoring device proposed in this study.

• 한국의류산업학회지
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• 제25권5호
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• pp.651-660
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• 2023

This study aimed to research the local production of conductive composite yarn, a source material used in textile-type electrodes and circuits. The physical properties of an internationally available conductive composite yarn were analyzed. To manufacture the conductive composite yarn, we selected one type of conductive yarn with Ag-coated polyamide of 150d 1 ply, along with two types of polyethylene terephthalate (PET) with circular and triangular cross-sections, both with 150d 1 ply. The conductive composite yarn samples were manufactured at 250, 500, 750, and 1000 turns per meter (TPM). For both conductive composite yarn samples manufactured from two types of PET filaments, the twist contraction rate of the sample with a triangular cross-section was stable. Among the samples, the tensile strength of the sample manufactured at 750 TPM was the highest at approximately 4.1gf/d; the overall linear resistance was approximately 5.0 Ω/cm, which is within the target range. It was confirmed that the triangular cross-section sample manufactured with 750 TPM had a similar linear resistance value to the advanced product despite the increase in the number of twists. In future studies, we plan tomanufacture samples by varying the twist conditions to derive the optimal conductive yarn suitable for smartwear and smart textile manufacturing conditions.

• 감성과학
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• 제13권3호
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• pp.467-474
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• 2010

최근 생체 신호 측정을 위한 기능성 의류는 동작 잡음에 의한 노이즈를 최대한 줄여 정확한 생체 신호를 측정 가능케 하는 것의 중요성에 대한 논의가 이루어지고 있다. 이에 본 연구는 영향 요인별 고려 사항을 반 영하여 3-리드(lead)방식의 은사 자수의 직물 전극을 개발하고, '일자형 절개 타입', '십자형절개 타입', '엑스형 절개 타입', '곡선 엑스형 절개 타입'의 총 네 가지 타입의 생체신호 센싱 스마트 의류의 시안을 설계하고 제작하였다. 디자인 시안은 민소매형태의 남성용 티셔츠로 신축성 있는 소재를 사용하여 인체 굴곡을 따라 의복과 전극이 밀착될 수 있도록 하였으며, 트랜스미터를 이용하여 메인 컴퓨터로 데이터가 무선 전송되게 하였다. 각 재모듈화형 의류 타입별 인체 동작에 의한 영향과 정지 및 동작 상태에서의 심전도 센싱 성능을 평가하기 위해 동작에 따른 전극의 변위를 측정하고, 심전도 측정 평가를 실시하여 SNR을 분석하였다. 본 실험 결과를 반영하여 의류 디자인 시안의 수정 및 보완 과정을 거친 후, 최종적으로 '연속-부착형', '삽입-분리형'의 두 가지 타입의 생체신호 센싱 스마트의류 디자인 모형의 모듈화 방안을 제시하였다.

• 한국의류산업학회지
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• 제17권6호
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• pp.1039-1049
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• 2015

The increase in the need for a 24 hour monitoring of biological signals has been accompanied by an increasing interest in wearable systems that can register ECG at any time and place. ECG-monitoring clothing is a wearable system that records heart function continuously, but there have been difficulties in making accurate measurements due to motion artifacts. Although various factors may cause noise in measurements due to motion, the variations in the body surface and clothing during movements that cause eventual the shifting and displacement of the electrodes is particularly noteworthy. Therefore, this study used biomedical body mapping and a motion-capture system to measure and analyze the changes in the body surface and garment during movements. It was deduced that the area where the friction and separation between the garment and skin is the lowest would be the appropriate location to place the ECG electrodes. For this study, 5 male and 5 female in their 20s were selected as subjects, and through their selected body movements, the changes in the garment and skin were analyzed using the motion-capture system. As a result, the area below the chest circumference and the area below the shoulder blades were proposed as the optimal location of electrode for ECG monitoring.

• 대한화학회지
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• 제41권11호
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• pp.575-580
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• 1997

Benzyl viologen의 전기 변색특성을 조사했다. 인가전압 2.6 V에서는 강한 전기변색 응답성을 나타내지만 반복 내구성이 뛰어나지 못하다. 이러한 현상은 전기 변색소자의 투명 유리전극인 ITO막이 전장하에서 손상을 입기 때문이라는 것을 알 수 있었다. 전압인가 전후의 ITO막의 면저항, XRD, SEM 결과로 부터 ITO막이 마모됨이 입증되었다.

• 한국전기전자재료학회논문지
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• 제36권5호
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• pp.525-530
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• 2023

Stretchable piezoelectric energy harvester (S-PEHs) based on composite materials are considered one of the potential candidates for realizing wearable self-powered devices for smart clothing and electronic skin. However, low energy conversion performance and expensive stretchable electrodes are major bottlenecks hindering the development and application of S-PEHs. Here, we fabricated the S-PEH by adopting the piezoelectric composites with enhanced stress transfer properties and kirigami-patterned textile electrodes. The optimum contents of piezoelectric BaTiO₃ nanoparticles inside the carbon nanotube/ecoflex composite were selected as 30 wt% considering the trade-off between stretchability and energy harvesting performance of the device. The final S-PEH shows an output voltage and mechanical stability of ~5 V and ~3,000 cycles under repeated 150% of tensile strain, respectively. This work presents a cost-effective and scalable way to fabricate stretchable piezoelectric devices for self-powered wearable electronic systems.

• 한국산학기술학회논문지
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• 제19권7호
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• pp.493-503
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• 2018

최근 국민생활 수준이 향상되면서, 많은 사람들이 건강에 관심을 갖고 발병 이전의 예방관리를 위하여 운동을 통해 셀프트레이닝을 하는 인구가 증가하고 있다. 일반적으로 근육의 언발란스는 자세의 비대칭성을 초래하고 인체의 비대칭성이 깨지게 되면 조정력, 순환작용, 내장기관의 변위 등을 동반하게 되어 각종 질병을 유발할 수 있다는 연구가 속속 나오고 있다. 본 연구에서는 최근 큰 관심을 받고 있는 스마트웨어 중에서 셀프트레이닝이 가능한 피트니스 웨어를 개발하고, 안드로이드 기반 어플리케이션을 통하여 시뮬레이션 함으로서 셀프트레이너 피트니스웨어 상용화 기술을 제시하고자 하였다. 셀프트레이너 피트니스웨어의 개발을 위하여 전도성 폴리머, 패션 디자인 및 봉제, 전기전자적인 기술이 융합하여 운동시 근육의 언발란스를 확인하고 스스로가 비대칭성을 교정할 수 있는 스마트웨어를 만들 수 있었다. 구체적으로는 최적 MWCNT 농도의 도출을 통한 폴리머 센서를 제작하고 도전성 섬유를 활용한 전극 신호선을 설계 및 부착하여 신호를 수집할 수 있는 최적의 위치에 전극을 부착하여 생체신호를 수집하였다. 이렇게 수집된 생체신호를 전기적 신호 변환하고 블루투스 통신을 이용하여 전달하는 Signal Module을 설계 및 제작하였으며, 소프트웨어 알고리즘을 이용한 노이즈 캔슬링과 안드로이드 기반의 셀프 트레이닝 애플리케이션을 융합하여 상용화가 가능한 셀프트레이너 피트니스 웨어의 제작방법을 제시하였다.

• 한국의류산업학회지
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• 제21권3호
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• pp.363-369
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• 2019

This study developed electroconductive textiles by coating polypyrrole to PET nonwoven-based Polyvinyl Alcohol (PVA) nanoweb made by electrospinning and applying the developed electrotextiles as ECG Electrodes. To find the optimum coating conditions for high electrical conductivity, the ratios of 2.6-Naphthalenedisulfonic acid with Disodium Salt (NDS) vs Ammonium Persulfate (APS) as an oxidant and a doping agent in the solution were changed from 3:7 to 7:3; the immersion time of the specimen in the solution was 1 hour. PVA nanowebs coated with polypyrrole under various conditions were filmed with FE-SEM. FT-IR analysis was also performed to examine the presence of polypyrrole nanoparticles in the PVA nanoweb. The electrical resistance of the treated specimens were measured with a Multimeter. Consequently, the PVA Nano Web was undamaged even after heat treatment that allowed for coating. Uniform polypyrrole nanoparticles then formed on the surface of the PVA nanoweb after coating. The measured electrical resistance was shown to be at least $12K{\Omega}/{\Box }$ from a maximum of $3,456K{\Omega}/{\Box }$. The proper amount of NDS content had a positive effect on the conductivity improvement of electroconductive textiles; in addition, the highest electrical conductivity was achieved with a ratio of 3:7 between NDS and APS.

• 감성과학
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• 제26권1호
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• pp.79-86
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• 2023

본 연구의 목적은 PET를 재활용하여 만든 물질재생 PET사를 함침공정을 통해 고전도성의 E-textile로 제작하는 것이다. 소수성의 성질을 가지고 있는 PET사는 virgin과 recycled 모두 함침공정을 통해 전자섬유로 제작되었을 때에 높은 전도성을 부여하기 힘들다는 특징이 있다. 함침공정의 효율성 향상을 위해 FEMTO SCIENCE사의 Covance-2mprfq 모델을 사용하여 재생 PET사로 이루어진 시료를 50w 5분, 10분간 플라즈마로 표면 개질하였다. 이 후 SWCNT 분산액(.1wt%, cobon 사)에 5분간 시료를 담근 후 패딩기(Padder, DAELIM lab)를 통해 시료 안쪽으로 용액이 잘 스며들도록 Dip-coating 진행하였다. 공정이 완료된 후 저항측정을 양끝점에서 멀티미터를 통해 측정하고 좀 더 넓은 전극을 통해 정밀하게 다시 측정하였다. 고찰한 결과 플라즈마 표면 개질을 통해 함침공정을 통한 고전도성 부여가 가능해졌음을 확인할 수 있었다. 10분간 표면 개질한 경우 저항이 최대 2.880배 감소하였다. 본 연구결과를 기반으로 스마트 웨어러블 분야에서 활용되는 E-textile 또한 recycle 소재로 제작함으로써 석유자원을 절약하고 탄소배출량을 감소시킬 수 있는 스마트 웨어러블 제품을 개발하고자 한다.