Polyurethane matrix incorporating PDMS-based self-healing microcapsules with enhanced mechanical and thermal stability

Chung, Ui Seok,Min, Ji Hong,Lee, Pyoung-Chan,Koh, Won-Gun Elsevier 2017 Colloids and surfaces. A, Physicochemical and engi Vol.518 No.-

<P><B>Abstract</B></P> <P>For the purpose of developing self-healing skin layers of instrument panels in automobiles, mechanically and thermally stable microcapsules containing healing agents were prepared and incorporated into a polyurethane (PU) matrix. Two different poly(urea-formaldehyde) (PUF) microcapsules containing either a polydimethylsiloxane (PDMS)/Pt catalyst (Pt) blend or crosslinker were synthesized using <I>in situ</I> emulsion polymerization. However, the resulting microcapsules were mechanically and thermally weak. More than 40% of the microcapsules were broken during the washing/drying process, and capsule decomposition began at 200°C. These properties of microcapsules were greatly enhanced by decreasing the capsule size and depositing an additional urea-formaldehyde (UF) layer onto pre-formed PUF microcapsules. The former was accomplished by tuning the stirring speed during the reaction and the latter by adding more urea components. Under optimized conditions, only approximately 10% of microcapsules were broken after the same washing/drying process, and the decomposition temperature was raised to 250°C. The two different optimized microcapsules were successfully embedded in a PU matrix and could be broken upon matrix cracking, thereby releasing the healing agent to the target areas <I>via</I> capillary effects. Subsequently, it was confirmed that the cracked portions were repaired through chemical and/or physical interactions within the healing system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mechanically and thermally stable self-healing microcapsules were prepared. </LI> <LI> Resultant microcapsules could contain PDMS-based healing agents. </LI> <LI> Microcapsule-embedded self-healing PU matrixes were prepared. </LI> <LI> Self-healing PU matrix could repair the scratch by releasing healing agents. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A Case Report of Migraine with Typical Aura on Korean Medical Treatments

Myoung-Ui Cho,Su-Yeon Lim,Hyun-A Jeon,Ji-Yeon Lee,Young-Joo Moon,Kwang-Chan Song,Young-Tak Koh 대한한방신경정신과학회 2018 동의신경정신과학회지 Vol.29 No.4

Objectives: The objective of this case report was to investigate the effect of Korean medicine therapy on migraine patients with typical aura. Methods: Acupuncture and chuna manual therapy were applied to outpatients once in 1 to 2 weeks, a total of 9 times, for about 11 weeks. A patient was diagnosed with ganyang-toutong and taeeumin dry-heat symptomatic pattern. Herbal medicine (Chongsanggeontong-tang Gagambang (淸上蠲痛湯加減方)) was prescribed for 15 days up to the 3rd visit, then another herbal medicine (Yeoldahanso-tang (熱多寒少湯)) prescribed for 15 days up to the 6th visit. MSQol and MIDAS were used as a tool at the start and after 9th treatment. The intensity and frequency of headache, frequency of aura and neck pain were examined on every visit. Results: According to the results, Korean traditional medicine described above had effect on the intensity and frequency of headache, frequency of aura and neck pain as well as an increase in the figure of MSQoL from 62 to 81 and decrease of MIDAS Disability from 18 to 7, Duration from 60 to 30, Pain score from 8 to 2. Conclusions: Migraine with typical aura classified as ganyang-toutong and taeeumin dry-heat symptomatic pattern can be alleviated by Korean traditional medicine.

A Case Report of Migraine with Typical Aura on Korean Medical Treatments

Cho, Myoung-Ui,Lim, Su-Yeon,Jeon, Hyun-A,Lee, Ji-Yeon,Moon, Young-Joo,Song, Kwang-Chan,Koh, Young-Tak The Korean Society of Oriental Neuropsychiatry 2018 동의신경정신과학회지 Vol.29 No.4

Objectives: The objective of this case report was to investigate the effect of Korean medicine therapy on migraine patients with typical aura. Methods: Acupuncture and chuna manual therapy were applied to outpatients once in 1 to 2 weeks, a total of 9 times, for about 11 weeks. A patient was diagnosed with ganyang-toutong and taeeumin dry-heat symptomatic pattern. Herbal medicine (Chongsanggeontong-tang Gagambang (淸上?痛湯加減方)) was prescribed for 15 days up to the 3rd visit, then another herbal medicine (Yeoldahanso-tang (熱多寒少湯)) prescribed for 15 days up to the 6th visit. MSQol and MIDAS were used as a tool at the start and after 9th treatment. The intensity and frequency of headache, frequency of aura and neck pain were examined on every visit. Results: According to the results, Korean traditional medicine described above had effect on the intensity and frequency of headache, frequency of aura and neck pain as well as an increase in the figure of MSQoL from 62 to 81 and decrease of MIDAS Disability from 18 to 7, Duration from 60 to 30, Pain score from 8 to 2. Conclusions: Migraine with typical aura classified as ganyang-toutong and taeeumin dry-heat symptomatic pattern can be alleviated by Korean traditional medicine.

유아대상 소프트웨어 교육을 위한 교수역량

고은현,문은경,홍찬의,이경희,최순덕,이영석,조정원,Koh, Eun-Hyeon,Moon, Eunkyung,Hong, Chan-Ui,Lee, KyungHee,Choi, Soonduk,Lee, Youngseok,Cho, Jungwon 한국융합학회 2021 한국융합학회논문지 Vol.12 No.10

이 연구의 목적은 유아대상 소프트웨어 교육을 위한 교수역량을 규명하는데 있다. 이를 위하여 문헌연구 및 유아교육, 컴퓨터교육, 교육공학 전문가 집단의 3차 델파이 조사를 시행하여 교수역량을 도출하였다. 그 결과 '소프트웨어 교육목적·목표 및 교육내용 선정', '소프트웨어 교육과정 계획 및 운영', '소프트웨어 교육과정 평가 및 환류'의 3개 역량군 및 15개 역량이 도출되었다. 그리고 연구결과 도출된 교수역량과 선행연구와의 관련성을 논의하고 결과의 시사점을 제시하였다. 이 연구에서 분석된 교수역량은 이후 교사교육 및 교육실행 관점에서 활용될 수 있을 것이다. The purpose of this study was to identify the teaching competency for software education for young children. Teaching competency was derived through literature study and Delphi survey of expert groups. The derived competences are composed of 'selection of software education objectives-goals and educational contents', 'software curriculum planning and implementation' and 'evaluation and feedback of software curriculum'. The derived competencies were found to be 15 competencies in a total of 3 competencies groups. The relationship between the derived competencies and previous studies was discussed and implications were presented. The teaching competency derived from this study can be used for teacher education and instructional practice.

유아 소프트웨어 교육 내용체계 구성을 위한 제언

이경희(KyungHee Lee),이영석(Youngseok Lee),고은현(Eun-Hyeon Koh),홍찬의(Chan-Ui Hong),조정원(Jungwon Cho) 한국컴퓨터교육학회 2018 한국컴퓨터교육학회 학술발표대회논문집 Vol.22 No.2

4차 산업혁명 시대는 더 이상 먼 미래가 아닌 현실로 다가왔다. 주요 선진국 뿐 아니라 세계 각국에서 미래 인재 양성을 위해 다양한 연구와 노력을 기울이고 있다. 이에 따른 소프트웨어 교육에 대한 요구를 수용하기 위해 교육과정의 변화 및 교과 편성을 활발하게 진행 중에 있고, 우리나라 역시 올해부터 ‘정보’교과를 중학교에서 34시간 이상 필수로 이수하도록 하였다. 본 논문에서는 국가 수준의 커리큘럼이 없이 사교육 중심으로 이루어지고 있는 유아대상 소프트웨어 교육의 내용체계를 제안하였다. 유아 대상 소프트웨어 교육은 누리과정에 자연스럽게 녹아들어 아이들이 행동 발달에 맞는 커리큘럼으로 개발되어 쉽고 재미있게 놀이와 체험을 통해 교육을 받을 수 있도록 지속적인 연구가 필요하다.

유아 소프트웨어 교육 효과성 검증을 위한 평가 도구 개발 제언

이경희(KyungHee Lee),이영석(Youngseok Lee),고은현(Eun-Hyeon Koh),홍찬의(Chan-Ui Hong),문은경(Eunkyung Moon),조정원(Jungwon Cho) 한국컴퓨터교육학회 2019 한국컴퓨터교육학회 학술발표대회논문집 Vol.23 No.2

혐기성 소화의 후처리로서 분리막의 여과특성 연구

추광호,이정학,백운화,고의찬,김상원,고종호 ( Kwang Ho Choo,Chung Hak Lee,Un Hwa Pek,Ui Chan Koh,Sang Won Kim,Jong Ho Koh ) 한국공업화학회 1992 공업화학 Vol.3 No.4

혐기성 소화액의 한외여과에 의한 후처리에서 분리막의 재질에 따른 여과특성을 연구하였다. 상이한 분리막의 여과특성을 정량적으로 평가하기 위해 저항 모델을 이용하였다. 소화액에 대한 플럭스의 양태는 초기의 물에 대한 분리막의 투과도에 무관하게 나타났다. 플루오로 폴리머 막의 경우에 유속의 증가에 따라 큰 플럭스의 향상을 보였는데 이것은 다른 분리막에 비해 막표면에 형성된 케이크층의 부착성이 약해 쉽게 제거될 수 있음을 시사해준다. 장시간 운전에서 플럭스의 감소는 오염층 저항의 중가에서 뿐만아니라 분극층 저항의 증가에서도 기인되었는데, 이와같은 계속적인 분극층 저항의 증가는 미생물의 분해 및 성장에 따른 케이크층 내의 성상변화를 반영할 수 있다. 막표면이 친수성인 셀룰로오즈 막은 소수성인 폴리술폰 막에 비해 낮은 막오염도를 보여주었다. 감압을 통해 플럭스를 5-10 L/m^2/h회복시킬 수 있었다. 세척 단계에서 여과저항을 평가함으로써 15분의 단시간내에 세척이 완료됨을 알 수 있었다. Filtration characteristics according to membrane materials were studied in the ultrafiltration of anaerobic digestion broth as a post treatment method. A series of resistances for different membranes were quantitatively assessed on the basis of the resistance-in-series model. Flux behavior observed with the digestion broth was irrelevant to initial water permeabilities of each membrane. The fluoro polymer membrane showed the most significant improvement of flux with increase of cross-flow velocity, which suggests that the cake layer formed on this membrane is more weakly attached to the membrane surface than those on the other membranes. Flux reduction during longtime running was attribused to the polarization layer resistance(R_p) as well as the fouling layer resistance(R_f). Continuous increase of R_p may reflect the variation in the characteristics of cake layers, which could result from size, shape, and structure changes due to lysis and growth of biomass. Hydrophilic cellulosic membrane had a much lower fouling tendency than hydrophobic polysulfone membrane. The depressurization method induced a small increase in flux of 5-10 L/m^2/h. During washing and cleaning, filtrability of each membrane was rapidly recovered within 15 minutes until a stationary value was reached.