Wireless powered wearable micro light-emitting diodes

Lee, Han Eol,Lee, Daewon,Lee, Tae-Ik,Shin, Jung Ho,Choi, Gwang-Mun,Kim, Cheolgyu,Lee, Seung Hyung,Lee, Jae Hee,Kim, Yong Ho,Kang, Seung-Mo,Park, Sang Hyun,Kang, Il-Suk,Kim, Taek-Soo,Bae, Byeong-Soo,Le Elsevier 2019 Nano energy Vol.55 No.-

<P><B>Abstract</B></P> <P>Wearable displays are considered as a bilateral communication tool in the hyperconnected era. Although several electronic clothing display was demonstrated, high power consumption issue still remained. Here, we present wireless powered wearable μLEDs (WμLEDs) with excellent stability. A custom-designed wireless power supply system operated a 30 × 30 WμLED array on a fabric. The WμLED stability was intensively investigated under bending, stretching, 85 °C/85% relative humidity and artificial sunlight conditions, showing the suitability of WμLED outdoor usage. Finally, a passive-matrix WμLED display successfully emitted a brilliant red glow on a fabric.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Wireless powered wearable μLEDs (WμLEDs) with excellent stability was realized by a custom-designed wireless energy supply system on a fabric. </LI> <LI> WμLED stability was investigated under bending, stretching, 85 °C/85% relative humidity and artificial sunlight conditions, showing the suitability of WμLED outdoor usage. </LI> <LI> A passive-matrix WμLED display successfully emitted a brilliant red glow on a fabric. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Optogenetic control of body movements via flexible vertical light-emitting diodes on brain surface

Lee, Seung Hyun,Kim, Jeongjin,Shin, Jung Ho,Lee, Han Eol,Kang, Il-Suk,Gwak, Kiuk,Kim, Dae-Shik,Kim, Daesoo,Lee, Keon Jae Elsevier 2018 Nano energy Vol.44 No.-

<P><B>Abstract</B></P> <P>The microstimulation of specific neural populations of the brain is one of the facile and reliable methods used in neuroscience for deduction of functional movement, complex behavior and even long-range connectivity. Recent advanced biomedical tools now employ flexible optoelectronic devices combined with optogenetic mouse models to induce high spatiotemporal modulation of specific brain activity. However, most current applications are limited to activation of small functional regions using blue-light driven channelrhodopsin. In this report, we introduce flexible AlGaInP vertical light-emitting diodes (VLEDs) for perturbation of specific functional areas of mouse cortex. Micro-scaled LEDs effectively compress the conductive balls dispersed in anisotropic conductive film (ACF) resulting red light emissions with high optical power density, capable of stimulating motor neurons deep below layer III from the brain surface. Selective operation of pulsed red light from f-VLEDs induces mouse body movements and synchronized electromyogram (EMG) signals. The expression of chrimson, red-shifted channelrhodopsin, enables red-light excitation of targeted functional area of motor cortex. This demonstration opens new opportunities for entire cortical mapping, to explore the connectivity between undefined motor areas in the mouse brain.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The flexible vertical light-emitting diodes (f-VLEDs) were fabricated by an anisotropic conductive film (ACF). </LI> <LI> The f-VLEDs showed the optical power density more than 25mW/mm<SUP>2</SUP>, enough to stimulate the motor neurons below layer III. </LI> <LI> The f-VLEDs illuminated the frontal motor cortex of the mouse to control the body movements with minimal tissue damage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Anatomical position of the mandibular canal in relation to the buccal cortical bone: relevance to sagittal split osteotomy

Han Eol Lee,Se Jin Han 대한구강악안면외과학회 2018 대한구강악안면외과학회지 Vol.44 No.4

Objectives: Classification of the degree of postoperative nerve damage according to contact with the mandibular canal and buccal cortical bone has been studied, but there is a lack of research on the difference in postoperative courses according to contact with buccal cortical bone. In this study, we divided patients into groups according to contact between the mandibular canal and the buccal cortical bone, and we compared the position of the mandibular canal in the second and first molar areas. Materials and Methods: Class III patients who visited the Dankook University Dental Hospital were included in this study. The following measurements were made at the second and first molar positions: (1) length between the outer margin of the mandibular canal and the buccal cortical margin (a); (2) mandibular thickness at the same level (b); (3) Buccolingual ratio=(a)/(b)×100; and (4) length between the inferior margin of the mandibular canal and the inferior cortical margin. Results: The distances from the canal to the buccal bone and from the canal to the inferior bone and mandibular thickness were significantly larger in Group II than in Group I. The buccolingual ratio of the canal was larger in Group II in the second molar region. Conclusion: If mandibular canal is in contact with the buccal cortical bone, the canal will run closer to the buccal bone and the inferior border of the mandible in the second and first molar regions.

Trichogenic Photostimulation Using Monolithic Flexible Vertical AlGaInP Light-Emitting Diodes

Lee, Han Eol,Lee, Seung Hyun,Jeong, Minju,Shin, Jung Ho,Ahn, Yuri,Kim, Daesoo,Oh, Sang Ho,Yun, Seok Hyun,Lee, Keon Jae American Chemical Society 2018 ACS NANO Vol.12 No.9

<P>Alopecia is considered an aesthetic, psychological, and social issue among modern people. Although laser-induced skin stimulation is utilized for depilation treatment, such treatment has significant drawbacks of high energy consumption, huge equipment size, and limited usage in daily life. Here, we present a wearable photostimulator for hair-growth applications using high-performance flexible red vertical light-emitting diodes (f-VLEDs). Flexible microscale LEDs were effectively fabricated by a simple monolithic fabrication process, resulting in high light output (∼30 mW mm<SUP>-2</SUP>), low forward voltage (∼2.8 V), and excellent flexibility for wearable biostimulation. Finally, trichogenic stimulation of a hairless mouse was achieved using high-performance red f-VLEDs with high thermal stability, device uniformity, and mechanical durability.</P> [FIG OMISSION]</BR>

비대칭 6상 영구자석 동기 전동기 구동 시스템의 동기화 전류 제어 기법 연구

김한얼(Han-Eol Kim),이원석(Won-Seok Lee),안효진(Hyo-Jin An),황선환(Seon-Hwan Hwang),이기창(Ki-Chagn Lee) 한국조명·전기설비학회 2021 한국조명·전기설비학회 학술대회논문집 Vol.2021 No.11

This paper proposes data on current inequality that may occur when configuring a redundancy system for asymmetric 6-phase permanent magnet synchronous motors. When dual inverters are used for the stability of the system, current inequality may occur due to asynchronization of the current controller. Current characteristics were analyze when current inequality occurs under experimental conditions.

뇌경색(腦梗塞)으로 인한 복시(複視) 증상 치료(治療) 1례(例)에 대한 증례보고(證例報告)

이한얼 ( Han Eol Lee ),안택원 ( Taek Won Ahn ) 대전대학교 한의학연구소 2007 혜화의학회지 Vol.16 No.1

Fe-V Chloric/Sulfuric Mixed Acid 레독스흐름전지 전극의 활성화 온도에 따른 전기화학적 성능 고찰

이한얼 ( Han Eol Lee ),김대업 ( Dae Eop Kim ),김철중 ( Cheol Joong Kim ),김태근 ( Taekeun Kim ) 한국공업화학회 2020 공업화학 Vol.31 No.6

레독스흐름전지(redox flow battery, RFB)의 구성 부품 중 전극은 전해액의 확산층 역할을 함과 동시에 전자의 통로 역할을 담당하여 출력에 직접적인 영향을 미치는 주요 부품이다. 본 연구는 Fe²⁺/Fe³⁺와 V²⁺/V³⁺를 레독스 커플로 사용한 RFB 시스템에 chloric/sulfuric mixed acid 지지 전해액을 사용한 경우 전극 종류 및 활성화 정도에 따른 용량, 쿨롱 효율, 에너지 효율을 비교하여 최적의 전극 및 활성화 정도를 제시하였다. 실험에 사용된 5종의 탄소 전극을 사용한 단일셀 평가에서 모두 이론 용량에 근사한 값을 보여 신뢰성을 확보하였으며, 사용된 전극 중 GFD4EA는 상대적으로 우수한 에너지 효율 및 충방전 용량을 나타내었다. 활성화 온도에 따른 전기화학적 성능 고찰을 위하여 GFD4EA 전극을 공기분위기 하에서 400, 450, 500, 600 및 700 ℃에서 열처리하여 활성화하였다. 질량 변화, 주사전자현미경(SEM) 및 XPS 분석을 통하여 활성화 전 후의 물성 변화를 관찰하였으며, 각각의 온도에서 활성화된 전극을 적용한 RFB 단일셀 평가를 실시하여 전기화학적 성능을 비교하였다. Among the components of redox flow battery (RFB), the electrode serves as a diffusion layer of an electrolyte and a path for electrons and also is a major component that directly affects the RFB performance. In this paper, chloric/sulfuric mixed acidwas used as a supporting electrolyte in RFB system with Fe²⁺/Fe³⁺ and V²⁺/V³⁺ as redox couple. The optimum electrode and activation temperature were suggested by comparing the capacity, coulombic efficiency and energy efficiency according to the electrode type and activation temperature. In the RFB single cell evaluation using 5 types of carbon electrodes used in the experiments, all of them showed close to the theoretical capacity to retain the reliability of the evaluation results. GFD4EA showed relatively excellent energy efficiency and charge/discharge capacity. In order to investigate the electrochemical performance according to the activation temperature, GFD4EA electrode was activated by heat treatment at different temperatures of 400, 450, 500, 600 and 700 ℃ under an air atmosphere. Changes in physical properties before and after the activation were observed using electrode mass retention, scanning electron microscope (SEM), XPS analysis, and electrochemical performance was compared by conducting RFB single evaluation using electrodes activated at each temperature given above.

학령기 이후 지적장애인의 진로 선택에 따른 지원요구

이한얼 ( Han Eol Lee ),조인수 ( In Soo Cho ) 한국특수아동학회 2012 특수아동교육연구 Vol.14 No.3

The purpose of this study was to analyze the support needs for post school individuals with intellectual disabilities according to career choice. The subjects of this study were divided into groups living or being educated in living faculties for the disabled, major courses at special schools, and colleges, and were composed of a total of 60 individuals with intellectual disabilities in 20 people each group. Questionnaires were written by interviewers to receive responses from teachers, employees, volunteers to identify the characteristics of the subject in each institution, and were used K-SIB and Support Needs Scale. As the results of this study, groups in major courses at special schools and groups in colleges have higher support needs than groups in living faculties. Most importance for community integration for individuals with intellectual disabilities is that depends on whether they are provided enough supports being considered their environment, not their personal abilities. Groups in colleges have higher support needs than groups in living faculties in activity subscales such as community living, lifelong learning, employment, and social. And groups in major courses at special schools have higher support needs than groups in living faculties in activity subscales such as employment and social. Individuals with intellectual disabilities can adapt and function properly to their environment if they are provided supports to meet their needs. This study suggests that intellectual disabilities should be provided context-sensitive supports due to the different areas and levels of support depending on their environment and they can adapt and function properly to their environment by receiving support being considered both their characteristics and environment.

특수교육대상아동의 통합교육 참여 수준에 대한교사와 학부모의 인식

이한얼 ( Han Eol Lee ) 한국지적장애교육학회 2014 지적장애연구 Vol.16 No.4

The purpose of this study is to investigate teacher``s and parents`` recognition of special education needs children``s participation in inclusive education. To accomplish of this purpose, a questionnaire was administered to 102 special education needs children``s inclusive class teachers and parents, and it was analyzed their recognition levels of inclusive education participation subareas divided subject learning, experiential activities, friendship activities and school event activities. The results of this study are as follows: First, teachers`` recognition levels of special education needs children``s participation are higher than parents`` in inclusive education total and all of subareas. Second, the lower grades teachers`` recognition levels of special education needs children``s participation are higher than the higher grades teachers`` in inclusive education total and subareas of subject learning, experiential activities, and friendship activities. Third, the lower grades parents`` recognition levels of special education needs children``s participation are higher than the higher grades parents`` in inclusive education total and subareas of subject learning, experiential activities, and school event activities. The parents`` recognition levels of special education needs children``s participation in inclusive education total and all of subareas at undercrowded class are higher than at the overcrowded class. The results of parents`` recognition being lower than teachers`` are due to be unsatisfied with parents`` expectations of special education needs children``s participation in inclusive education. The suggestions of these findings are as follows: First, there should be various ways to ensure special education needs children``s participation of inclusive education from the perspective of the education consumers and it is necessary to try to improve parents`` recognition of methods and contents in inclusive education. Second, it is necessary to reduce the number of students in inclusive classes in the appropriate level and it should be identified and eliminated disturbance factors on special education needs children``s participation of inclusive education.

지적,발달장애인 지원 체계에 대한 이론적 근거 탐색

이한얼 ( Han Eol Lee ) 한국지적장애교육학회 2013 지적장애연구 Vol.15 No.1

To expel the theoretical basis of support systems for people with intellectual and developmental disabilities, the results of this study on human performance technology, ecology and functionality approaches are as follows: First, human performance technology approach can be analyzed detailedly and elaborately for humans to perform each step and has strengths to be a possible holistic and systematic approach. Accordingly, human performance technology approach provides a technological and scientific basis for support systems formulating overall and comprehensive strategies of support systems for people with intellectual and developmental disabilities. Second, ecology approach provides justifiability to supports for people with intellectual and developmental disabilities formulating various potential for individuals` change in context. In addition, Accordingly, human performance technology approach provides a technological and scientific basis for support systems formulating overall and comprehensive strategies of support systems for people with intellectual and developmental disabilities. Second, ecology approach provides justifiability to supports for people with intellectual and developmental disabilities formulating various potential for individuals` change in context. In addition, support systems through ecology approach focus on the interactions between them and their environment and provide a rationale of systematic supports considering a variety of dimensions. Third, functionality approach enhances the understanding of intellectual and developmental disability to integrate a functional and social-ecological approach, and it enables a practical and more holistic approach on classification, support planning, preparation, assessment, etc. An integrated approach through multi-dimensional assessment in functionality approach helps to more easily understand structure of intellectual and developmental disability, and it provides a rationale to understand the dimensions and complexities of support systems for people with intellectual and developmental disabilities.