In-depth considerations for better polyelectrolytes as interfacial materials in polymer solar cells

Yeo, Jun-Seok,Kang, Minji,Jung, Yen-Sook,Kang, Rira,Lee, Seung-Hoon,Heo, Youn-Jung,Jin, Sung-Ho,Kim, Dong-Yu,Na, Seok-In Elsevier 2016 Nano energy Vol.21 No.-

<P><B>Abstract</B></P> <P>We perform a comprehensive study to achieve better polyelectrolytes (PEs) as electron-transport layers (ETLs) in polymer solar cells (PSCs). Three well-known PEs – PFN, PEIE, and WPF – are chosen as model systems and investigated with variations in their backbone structures and the state of the amine functionalities on their side chains. Respectively optimized PSCs using the three PEs exhibit different cell-performances, mainly owing to the diode characteristics of built-in potential and recombination strength. To identify how such deviated device-performances correlate with the structural features of PEs, the modulated interfaces of ITO/PEs and PEs/active layer are studied in detail. It is found that conjugated backbones and larger counter-anions on side chains can promote the modulation of ITO work functions (WFs) and that a large amount of protonated amines on PEs is beneficial for junction properties with a subsequent active layer. Additionally, our results indicate that interfacial dipole and electrical doping between the PE and active layer, in addition to WF modulation of the ITO cathode, are important for device efficiency. Accordingly, with the aid of the molecular features of PEIE, PEIE-PSCs exhibit excellent device efficiency and stability compared with PFN- and WPF-PSCs. In the PTB7-th:PC<SUB>71</SUB>BM system, a remarkable power-conversion efficiency of 9.97% is achieved with a single PEIE ETL.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chemical structure and performance of polyelectrolytes (PEs) in PSCs are correlated. </LI> <LI> Interfacial dipole and doping between PEs and active layer lead to efficient PSCs. </LI> <LI> PEIE-based PSCs have excellent device efficiency and high stability. </LI> <LI> Especially, in the PTB7-th system, encouraging efficiency of 9.97% is achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

비골 골절의 임상적 고찰

변웅래,여환호,양인석,김영균 大韓顎顔面成形再建外科學會 1994 Maxillofacial Plastic Reconstructive Surgery Vol.16 No.4

Because of the prominence of the nose and its central location, it is the most frequently encountered fractures in the face. Yet reports about the nasal bone fractures are virtually rare in the oral and maxillofacial surgical literatures. This sis a retrospective study on 19 nasal bone fractures treated in Chosun university hospital Department of Oral & Maxillofacial Surgery from Jan. 1991 to Sep. 1993, under admission to our Dept. and the obtained results were as follows. 1. Of the 240 patients with facial bone fractures, 28 patients suffered nasal fractures(12%) and male to female ratio was 5.3:1. 2. The most frequent cause was traffic accidents(39%)m, the next fall down(36%), first blow(4%). 3. The age frequency was the highest in the fifth decade (32%). 4. Clinical classification of nasal fractures was simple fractures(74%), comminuted fractures(26%), and single fractures(37%), combined fractures(63%). 5. The most frequently combined site was msxilla(50%). 6. Treatments of nasal fractures were closed reduction(63%), open reduction(5%), and secondary rhinoplasty(32%). 7. The initial treatment time from accident was 1.7 days in single fractures, and 3.5 days in combined fractures, and the period of splint retained was about 8.2 days in single fracture, about 8.7 in combined fracture. 8. It was necessary to treat secondarily in delayed treatment, and all treatment methods showed relatively good prognosis. 9. Closed reduction was treated under local anesthesia, but open reduction & secondary rhinoplasty was treated under general anesthesia except 1 case. 10. The complications were disturbance of swellings 5 cases, eithetic problem 5 cases, epiphora 3 cases, abnormal sensation 6 cases in relation with other fractures.

과학 영재를 위한 캠프 운영과 교육 프로그램의 개발 준거

여상인,노석구,강호감,이희순,홍석인,송상헌,정동권 인천교육대학교 과학교육연구소 2003 과학교육논총 Vol.15 No.-

본 연구는 영재 프로그램과 그 운영의 적절성과 타당성을 판단하는데 기초 자료가 될 수 있는 준거를 추출하기 위한 연구이다. 과학캠프 활동 프로그램에 대한 학생들의 흥미와 유익성, 영재캠프 운영에 관련된 문항으로 구성된 설문지를 캠프에 참가한 학생과 그 학부모에게 실시하여 분석하였다. 영재 캠프에 참가한 학생은 직접 참여할 수 있으면서 지적 호기심을 자극하는 활동에 흥미를 느꼈고, 놀이 요소가 포함된 프로그램을 많이 선호하였다. 학생들이 모르거나, 중요하다고 생각하거나, 일상생활에 적용할 수 있는 과학 지식이나 원리를 배웠다고 인식하는 경우, 유익한 프로그램으로 인식하였다. 과학 영재 캠프의 운영에 있어서 많은 학생이 방학 중에 1주일 정도의 기간으로 합숙하는 프로그램 운영 방식을 선호하였다. 이러한 연구 결과를 토대로 본 연구에서는 캠프 활동 프로그램과 운영에 대한 몇 가지 시사점을 제안하였다. This study is to find out criteria and basic data to evaluate effectiveness and validity of program for gifted children in science. To this purpose, a questionnaire to investigate the perception of interest and usefulness for camp activities was administered to the gifted children registered to science camp. By analyzing their responses, we could conclude that the gifted children thought the activities, which stimulating their curiosity or providing opportunities to participate, to be interesting to them. They preferred the activities like a play or a game and considered that a useful activities should have something worth-learning. They and their parents preferred to stay in a camp for a week. Based on this research, we suggested some implications about academic camp program for gifted children in science.

이차구순열 결손의 치료

임석균,박인순,여환호,지재휴,김영균,김수관 大韓顎顔面成形再建外科學會 1997 Maxillofacial Plastic Reconstructive Surgery Vol.19 No.2

Despite the current accomplishments with the repair of cleft lips, the surgical management of the nasal deformity remains a functional and aesthetic dilemma for patients, their families, and reconstructive surgeons. Recent improvements in the understanding and technical execution of te primary cleft lip repair have significantly reduced secondary sequelae and the consequent need for secondary surgical correction. But, secondary surgical corrections are necessary according to numerous factors. Such factors include the secondary surgical corrections are necessary according to numerous factors. Such factors include the severity of the initial deformity, the surgical plan, precision of execution of the primary repair, and success of the postoperative management. We preformed the secondary correction of cleft lip and palate in 11 patients via various methods. In conclusion, primary repair of cleft lip and palate patients is the most important to prevent the secondary deformities, and most of cleft lip and palate with secondary deformities must be treated with combined cheiloplasty and rhinoplasty.

서로 다른 형태의 임플란트의 식립토크가 골에 미치는 열변화에 관한 연구

김민호,여인성,김성훈,한중석,이재봉,양재호,Kim, Min-Ho,Yeo, In-Sung,Kim, Sung-Hun,Han, Jung-Seok,Lee, Jai-Bong,Yang, Jae-Ho 대한치과보철학회 2011 대한치과보철학회지 Vol.49 No.2

연구 목적: 임플란트 식립시에 발생할 수 있는 열변화는 임플란트의 실패를 초래할 수 있다. 식립토크에 따른 열변화 양상을 파악함으로 임플란트의 형태에 따른 차이점과 적절한 식립토크가 어떤 것인지 파악하고자 한다. 연구 재료 및 방법: 실험재료로는 두께 15 - 20 mm의 소 견갑골을 가로 35 mm, 세로 40 - 50 mm 크기가 되도록 골편으로 자르고 이중에 피질골의 두께가 2 - 3 mm 되는 표본을 선정한 후 표본의 반을 $36.5^{\circ}C$ 수조에 실온 $25^{\circ}C$에 노출 시켜 내부 온도는 평균 $36.5^{\circ}C$, 표면온도 $28^{\circ}C$가 되도록 설계하였다. $4.5{\times}10\;mm$의 외부육각을 가지는 Br${\aa}$nemark 형태의 임플란트와 $4.8{\times}10\;mm$의 Microthread 형태를 지니는 내부연결 형태의 임플란트를 과도한 식립토크로 식립하고 온도 측정은 계측점에서 0.2 mm 이내에 열전대를 위치시켜 기록하였다. 삼차원유한요소 분석은 골의 형태를 가로 4 cm, 세로 4 cm, 높이 2 cm의 직육면체로 가정하고, 직육면체 윗면에서 2 mm까지를 피질골, 그 아랫부분을 해면골이라고 가정하였다. 마찰열은 매식이 종료된 상황에서 골에 남는 cavity 모양을 기초로 경계조건을 부여하였다. CAD 프로그램인 SolidWorks 소프트웨어를 이용하였고, 이를 유한요소 구조해석용 프로그램인 Abaqus 6.9-1로 불러들여 해석하였다. 결과 및 결론: In vitro실험에서 Microthread type의 임플란트가 상대적으로 더 높은 최고점 온도를 보여주고 있으며 이는 임플란트의 형태에 따른 마찰열 발생이 주요 원인으로 보인다. 유한요소분석을 통해 살펴본 결과 Br${\aa}$nemark 형태의 임플란트의 경우 50 Ncm이상에서 Microthread를 가지는 형태의 경우에는 35 Ncm이상에서 Eriksson 등이 보고한 역치를 초과하는 온도가 발생하였다. 이를 통해 볼 때 Microthread type 이 식립토크에 따른 온도 증가가 더 민감함을 알 수 있다. 실험결과를 통해서 서로 다른 형태의 임플란트 식립시에 임플란트의 형태에 따라 적절한 삽입토크를 부여하는 것이 성공적인 임플란트 시술에 중요한 요소 중에 하나임을 알 수 있었다. 특히 Microthread를 갖는 임플란트 형태는 높은 초기고정성을 얻을 수 있다는 장점이 있는 반면 과도한 식립 토크로 인한 열 손상 가능성을 가질 수 있으므로 골량과 골질의 신중한 평가와 적절한 수술기법이 필요할 것으로 생각된다. Purpose: This study aims at investigating the influence of various insertion torques on thermal changes of bone. A proper insertion torque is derived based on the thermal analysis with two different implant designs. Materials and methods: For implant materials, bovine scapula bone of 15 - 20 mm thickness was cut into 35 mm by 40 - 50 mm pieces. Of these, the pieces having 2 - 3 mm thickness cortical bone were used as samples. Then, the half of the sample was immersed in a bath of $36.5^{\circ}C$ and the other half was exposed to ambient temperature of $25^{\circ}C$, so that the inner and surface temperatures reached $36.5^{\circ}C$ and $28^{\circ}C$, respectively. Two types of implants ($4.5{\times}10\;mm$ Br${\aa}$nemark type, $4.8{\times}10\;mm$ Microthread type) were inserted into bovine scapula bone and the temperature was measured by a thermocouple at 0.2 mm from the measuring point. Finite element method (FEM) was used to analyze the thermal changes at contacting surface assuming that the sample is a cube of $4\;cm{\times}4\;cm{\times}2\;cm$ and a layer up to 2 mm from the top is cortical bone and below is a cancellous bone. Boundary conditions were set on the basis of the shape of cavity after implants. SolidWorks was used as a CAD program with the help of Abaqus 6.9-1. Results: In the in-vitro experiment, the Microhead type implant gives a higher maximum temperature than that of the Br${\aa}$nemark type, which is attributed to high frictional heat that is associated with the implant shape. In both types, an Eriksson threshold was observed at torques of 50 Ncm (Br${\aa}$nemark) and 35 Ncm (Microthread type), respectively. Based on these findings, the Microthread type implant is more affected by insertion torques. Conclusion: This study demonstrate that a proper choice of insertion torque is important when using a specific type of implant. In particular, for the Microthread type implant, possible bone damage may be expected as a result of frictional heat, which compensates for initial high success rate of fixation. Therefore, the insertion torque should be adjusted for each implant design. Furthermore, the operation skills should be carefully chosen for each implant type and insertion torque.

Organic Solar Cells: Solution‐Processable Reduced Graphene Oxide as a Novel Alternative to PEDOT:PSS Hole Transport Layers for Highly Efficient and Stable Polymer Solar Cells (Adv. Mater. 42/2011)

Yun, Jin‐,Mun,Yeo, Jun‐,Seok,Kim, Juhwan,Jeong, Hyung‐,Gu,Kim, Dong‐,Yu,Noh, Yong‐,Jin,Kim, Seok‐,Soon,Ku, Bon‐,Cheol,Na, Seok‐,In WILEY‐VCH Verlag 2011 Advanced Materials Vol.23 No.42

<P>Solution‐processable reduced graphene oxide as a hole‐transporting layer for highly efficient and stable organic solar cells is reported on page 4923 by Dong‐Yu Kim, Seok‐In Na, and co‐workers. Introduction of a newly reduced graphene oxide by simple solution processing into solar cells dramatically raises the cell efficiency and cell life‐time. The results will allow full use of chemically reduced graphene and will advance the realization of carbon‐based printable optoelectronic devices. </P>

지반의 진행성 파괴와 기초의 크기 효과를 고려한 지지력 특성에 관한 실험적 연구

임종철,안민홍,홍석우,강정철,여종인 釜山大學校生産技術硏究所 1999 生産技術硏究所論文集 Vol.56 No.-

얕은 기초의 지지력을 산정하는데 있어서 기존 이론의 지지력계수(Nc,Nr,Nq)는 흙의 내부마찰 각 φ만의 함수로 표현되어져 있다. 그리고 조밀한 모래지반에서는 동시파괴(전반전단파괴)가 발생한다고 가정하고 있다. 본 논문에서는 주문지 표준사를 이용하여 중간·조밀한 모래지반을 제작하여, 재하폭 B를 변화시켜 실험하였다. 실험 결과, 조밀한 모래지반에서도 진행성파괴가 발생하며, 지지력계수 Nr의 평가에 있어서 내부마찰각 φ뿐만 아니라, 재하폭 B의 영향이 고려되어져야 함을 알 수 있었다. The bearing capacity factors(Nc,Nr,Nq) of an existing formulae are the function of only internal friction angle(φ) in calculating of ultimate bearing capacity of shallow foundations. And it is assumed that the simultaneous failure(general shear failure) occurs in the dense sand. In this study, the medium to dense sand grounds are formed by Joomunjin standard sand, and the laboratory medel tests are made with the change of load-width(B). By test it is known that the progressive failure is also occurred in the dense sand ground and so the bearing capacity factor(Nr) should be considered for not only internal friction angle(φ) but also the effect of load-width(B).

Comparison of High-Dose Corticosteroid Pulse Therapy and Combination Therapy Using Oral Cyclosporine with Low-Dose Corticosteroid in Severe Alopecia Areata

( In Kwon Yeo ),( Eun Jung Ko ),( Yeon A No ),( Ee Seok Lim ),( Kui Young Park ),( Kapsok Li ),( Beom Joon Kim ),( Seong Jun Seo ),( Myeung Nam Kim ),( Chang Kwun Hong ) 대한피부과학회 2015 Annals of Dermatology Vol.27 No.6

Background: Severe alopecia areata (AA) is resistant to conventional treatment. Although systemic oral corticosteroids are an effective treatment for patients with severe AA, those drugs have many adverse effects. Corticosteroid pulse therapy has been introduced to increase therapeutic effects and reduce adverse effects. However, the treatment modality in severe AA is still controversial. Objective: To evaluate the effectiveness of corticosteroid pulse therapy in patients with severe AA compared with treatment with oral cyclosporine with corticosteroid. Methods: A total of 82 patients with severe AA were treated with corticosteroid pulse therapy, and 60 patients were treated with oral cyclosporine with corticosteroid. Both groups were retrospectively evaluated for therapeutic efficacy according to AA type and disease duration. Results: In 82 patients treated with corticosteroid pulse therapy, 53 (64.6%) were good responders (>50% hair regrowth). Patients with the plurifocal (PF) type of AA and those with a short disease duration (≤3 months) showed better responses. In 60 patients treated with oral cyclosporine with corticosteroid, 30 (50.0%) patients showed a good response. The AA type or disease duration, however, did not significantly affect the response to treatment. Conclusion: Corticosteroid pulse therapy may be a better treatment option than combination therapy in severe AA patients with the PF type. (Ann Dermatol 27(6) 676∼681, 2015)

Anti-hyperlipidemic Effect of Polyphenol Extract (Seapolynol^TM) and Dieckol Isolated from Ecklonia cava in in vivo and in vitro Models

Yeo, A-Reum,Lee, Jung-Lim,Tae, In-Hwan,Park, Seok-Rae,Cho, Young-Ho,Lee, Bong-Ho,Shin, Hyeon-Cheol,Kim, Seong-Ho,Yoo, Yung-Choon The Korean Society of Food Science and Nutrition 2012 Preventive Nutrition and Food Science Vol.17 No.1

The inhibitory effect of polyphenol extracts (Seapolynol$^{TM}$, SPN) of the marine brown algae Ecklonia cava and dieckol, a major component of SPN, on hyperlipidemia was investigated in ICR mice fed a high-fat diet (HFD) for five weeks. For analysis of the anti-hyperlipidemic effects of SPN and dieckol, these two agents were given orally on a daily basis to HFD-fed mice for four weeks, starting one week after the beginning of HFD feeding. Groups administered with SPN as well as dieckol showed lower body weight gains than the HFD only group. Administration of SPN and dieckol also resulted in a significant reduction of the level of total cholesterol (TCHO), triglyceride (TG), and low-density lipoprotein (LDL) cholesterol in the serum of HFD-fed mice. In Oil Red O staining using 3T3-L1 preadipocytes, it was shown that both SPN and dieckol markedly inhibited lipid accumulation of 3T3-L1 cells. Furthermore, SPN and dieckol (50 ${\mu}g$/mL) significantly inhibited 3-hydroxyl-methyl glutaryl coenzyme A (HMGCoA) reductase activity in vitro. Taken together, these results suggest that polyphenols of Ecklonia cava (SPN) and dieckol reduce body weight gain and fat accumulation in HFD-induced obese mice, and that their hypolipidemic effect is related to the inhibition of adipogenesis of adipocytes and HMGCoA reductase activity.

Metabolic engineering of Candida tropicalis for efficient biomass hemicellulose hydrolysate utilization

In Seok Yeo,Woo Yong Shim,Jung Hoe Kim 한국당과학회 2017 한국당과학회 학술대회 Vol.2017 No.01

Xylose is the most abundant carbohydrate in biomass hemicellulose hydrolysate. However, most living organisms are unable to uptake this five-carbon sugar. A few microbes including Candida tropicalis and Pichia stipitis can metabolize this monosaccharide. We focused on genetically engineering C. tropicalis to utilize xylose rapidly. Xylitol reductase (XR), xylitol dehydrogenase (XDH) and xylulokinase (XK) are responsible for xylose utilization in yeast. But xylitol is accumulated during xylose metabolism as byproduct. Hence, xylose isomerase (XI) gene in fungal xylose pathway was introduced not to produce xylitol. Glyceraldehyde 3-phosphate dehyderogenase (GAPDH) promoter was used throughout the experiments to transcribe genes constantly without glucose repression, and the fungal XI gene was codon-optimized for correct amino acids in alternative codon usage system. In addition, the composition of media was modified to minimize xylitol production. To increase xylose consumption rate more fast, additional three genes were overexpressed which encode transketolase (TKL), transaldolase (TAL) and xylulokinase (XK) gene. Also, pho13 gene was disrupted. For overexpression and disruption harboring genes, above four genes were identified by polymerase chain reaction with specific-designed primers based on sequence homology. The resulting genetically engineered organism consumed 50g xylose/L in 72 hours from chemically defined media with 20g glucose/L similar to biomass hemicellulose hydrolysate. By using this strain, we can use biomass hemicellulose hydrolysate more effectively.