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>

근첨하 분절 골절단술을 병행한 Ⅲ급 양악 전돌증의 교정치료 증례

정미향,남동석 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.3

양악 전돌은 흔히 접하는 부정교합 증례로서, 대부분 상하순의 전돌에 의한 안모 심미성의 손상을 주소로 내원한다. 이러한 증례는 제1소구치를 발거하고 그 공간을 이용하여 전치부를 견인하여 치료하는 경우가 많으며, 성공적인 치료결과를 얻을 수 있다. 그러나, 성인 환자의 경우에는 환자의 협조도 불량으로 인한 악외 고정원 사용의 불량, 치료기간의 장기화, 치조골이 충분하지 못한 경우등에 있어서의 치근 흡수량의 증가, 구외 장치 사용으로 인한 환자의 사회심리적 부담감등의 부작용이 있다. 이의 해결방안의 하나인 근첨하 분절 골절단술은 고정원의 절대 보존, 치료기간의 단축, 구외 고정원 사용 필요성 제거 및 이를 통한 환자의 협조도 증가 등의 장점을 가지고 있다. 이에, 제 1소구치 발거 및 이 부위를 이용한 근첨하분절 골절단술을 병행하여 치료한 치아치조 전돌의 증례를 치료 전후의 두부 방사선 계측 사진 및 연구 모형을 통해 비교분석하여 변화를 살펴보고. 이의 장단점을 고찰해 보도록 하고자 한다. Bimaxillary protrusion can be treated effectively in growing patients and in adults with conventional orthodontic therapy. However, In the adult patient, combined surgical and orthodontic treatment modalities may offer distinct advantages over such conventional therapy. In those cases complicate by vertical jaw dysplasia, sagittal dysplasia, or transverse skeletal discrepancy in addition to bimaxillary protrusion, the possibilities of obtaining successful results through orthodontic treatment alone greatly diminish. Surgical retraction of both maxillary and mandibular anterior segments with subapical osteotomies and ostectomies in the extraction site may be a good treatment alternative. Treatment time and possible adverse effects of lengthy orthodontic therapy may be reduced and optimum esthetic improvement may be facilitated. On the following cases, patient who had bimaxillary protrusion with Angle Class III malocclusion was treated with combined orthodontic - surgical therapy by anterior subapical segmental osteotomies.

SWS 490B 강의 피로균열 진전시 음향방출 거동과 파단면 관계

鄭中采,尹東珍,朴徽立,金基福,李承錫 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.8

The objective of this study was to investigate the effect of AE activities during fatigue test. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity was discussed. From the experimental results, the features of specific parameters such as the length of crack growth, the AE energy and the AE peak amplitude, showed similar trend in their increase as the stress intensity factor increased. The fracture surface of test specimens revealed both intergranular fracture and transgranular fracture. Size and density of slip band were varied as the stress intensity factor increased and AE activities were different according to the slip band shape.

저선량 감마선 조사가 왕겨의 항산화능에 미치는 영향

정석문,김정한,김동열,육홍선,변명우,이승철 慶南大學校 附設 基礎科學硏究所 2002 硏究論文集 Vol.16 No.-

왕겨에 200, 400, 600, 800 및 1000 Gy의 저선량의 감마선을 조사하여 항산화능의 변화를 관찰하였다. 총 페놀 화합물의 양은 무처리구의 경우 0.184 mM를 나타내었고, 200 Gy로 감마선을 조사하였을 때는 0.215 mM로 약간 증가함을 보였으나 이후 차츰 감소하였다. 전자 공여능은 무처리구에 비해 처리구의 경우 조사 선량별로 조금씩의 차이만 있을 뿐, 조사 선량에 대한 왕겨의 전자 공여능은 유의적인 큰 변화 없이 비슷한 활성을 보였다. Fe^2+-ions 킬레이팅 활성은 무처리구의 경우 68.25%를 나타내었으며, 200, 400, 600 및 800 Cy 에서는 각각 86.45, 85.61, 86.65 및 82.84%로서 무처리구보다는 증가함을 보였으나, 1000 Gy에서는 74.67%로 감소하였다. 지질 과산화 억제능은 무처리구에 비해 처리구는 약간의 증가를 보였으나 효과는 미비하였다. We studied the effect of small-dose of γ-irradiation to rice hull(RH) for its antioxidant ability. The RH was treated with 200, 400, 600, 800, and 1000 Gy of γ-ray at 70 Gy/min. Total phenol amount of unirradiated RH was 0,184 mM, after irradiation at 200 Gy it increased to 0,215 mM, while irradiation above 400 Gy up to 1000 Gy decreased that to unirradiated level. The electron donating ability of RH did not show significant change depend on irradiation. The chelating ability for Fe^2+ of unirradiated RH was 68.25 %, while that of 200, 400, 600 and 800 Gy irradiated RH showed 86.45, 85.61, 86.65 and 82.84 % respectively, but, 1000 Gy was decreased to 74.67 %. According to TBARS analyses, inhibition ability of lipid peroxidation by RH was not affected by γ-irradiation.

장방형내 저온 단일 수평 원관 주위의 동결현상에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

An experimental study on water in a rectangular cavity with a horizontal cooling tube was carried out to investigate the flow character and thermal behavior in the system. Each experiment was performed with variation of initial temperature and cooling tube temperature. When the cooling tube temperature was -4℃, the supercooling phenomenon was observed regardless of the initial water temperature. And the case of cooling tube temperature was -6℃ with initial temperature was below 4℃, the supercooling phenomenon was also observedin the large region of the test section. When the cooling tube temperature was -10℃, the local region of supercooling phenomenon was observed during the freezing process. And the higher initial temperature was, the higher supercooling degree and the less difference of the ice thickness between upward and downward was observed. It is shown that by controllingthe supercooling phenomena and the cooling tube temperature, it would lead to an increase efficiency of ice making.

수직 냉각면이 있는 정방형내 성층유체의 열적거동에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

This study was investigated by experimentals on the thermal behavior of stratified fluids in the square cavity with the vertical cooling surface by variation of initial temperature and cooling surface temperature and concluded as follows: 1. When the cooling surface temperature of the square cavity was -4℃. the supercooling phenomena was occurred every times regardless initial temperature of fluids and when -6℃ freezing was begun with out supercooling phenomena. 2. The higher the initial temperature was, the longer supercooling phenomena duration was, and the longer the supercooling phnomena was, the higher the temperature of the upper fluids was. 3. When the supercooling phenomena of water was occurred, the rate of temperature decrease of silicon oil was higher and when there was no supercooling phenomena, it was almost same the rate of temperature decrease.

3차원 전산화단층촬영 영상을 이용한 얼굴 연조직 두께 계측

정호걸,김기덕,한승호,신동원,허경석,이제범,박혁,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. Materials and Methods : One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side, The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. Conclusion : The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology. (Korean J Oral Maxillofac Radiol 2006; 36 : 49-54)

우리나라의 철강산업에서 대기오염의 관리 및 방지현황에 관한 연구

김동술,김신도,유정석 경희대학교 환경연구소 1994 環境硏究 論文集 Vol.5 No.-

국가 경제발전에 크게 기여하고 있는 철강산업은 에너지를 과소비하며, 폐기물을 대량 발생하는 공해 유발업종이기도 하다. 1970년 이후 철강산업은 지속적인 산업발전을 위하여, 생산설비의 확장과 함께, 대기의 질을 개선시키기 위하여 방지설비에도 많은 비용을 투자하였다. 대부분 산업체의 경우처럼, 국내 철강산업 역시 개발과 환경보존과의 조화라는 어려움을 가지고 있었으며, 각종 대기환경정책의 변화에도 적극적으로 대처하고 있다. 본 연구는 철강산업의 국가 경제발전에 주요 공헌산업으로서의 역할을 계속 유지하며, 철강산업이 국내 환경개선에도 선도적인 역할을 수행할 수 있도록, 우리실정에 적합한 대기오염 배출규제의 방향을 제시하고자 하였다. 이를 위해, 본 연구는 철강산업의 환경현황과 문제점, 대기오염 방지시설의 현황과 처리에 대한 경제성 등을 연구조사하였으며, 우리나라 대기환경규제의 비합리성을 지적하였다.

성인 Ⅱ급 환자의 안면 수직고경및 교합평면의 특징에 관한 두부방사선학적 연구

남동석,정미향 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.2

본 연구에서는 Ⅱ급 부정교합자의 교합평면의 형태적 특징을 관찰하고, 안면의 수직고경과 연관지어 정상교합군과 비교하여 교합평면의 발현에 영향을 미치는 골격성, 치성요인의 기여정도를 알아보고자 했다. 성장과 연령군의 변이를 배제하기 위해 성장이 완료된 성인만을 연구대상으로 정하였다. 정상교합자 50명과 서울대학교 치과진료부 교정과에 내원한 50명의 Angle class Ⅱ 환자의 측모 두부방사선 계측사진분석을 통하여 다음의 결과를 얻었다. 1. Ⅱ급 부정교합자군에서 정상군보다 유의하게 크게 관찰된 교합평면의 경사도는 다음과 같다.; SN-FOP, FH-BOP, MP-BOP, AB-BOP, AB-FOP, Facial plane-BOP, FP-FOP 2. Ⅱ급 부정교합자군에서는 정상군에 비해 후안면 고경, 특히 후하안면고경이 유의한 차이를 보였다. 3. 교합평면과 상하악 전치가 이루는 각은 Ⅱ급 부정교합군에서 통계적으로 유의하게 컸고, 대구치와 이루는 각은 상악대구치와 해부학적 교합평면이 이루는 각만이 통계적으로 유의한 차이를 나타냈다. 4. 교합평면의 위치를 결정하는 요소중에서 하악절치에서 하악평면에 이르는 거리만이 Ⅱ급 부정교합군에서 유의하게 컸다. 5. Ⅱ급 부정교합군에서는 수직피개도와 교합평면 경사도의 상관관계가 존재하지만, 정상 교합군에서는 수직피개도와 교합평면 경사도간에 상관관계가 존재하지 않았다. This study was investigated to assess the difference of facial height and occlusal plane inclination between normal occlusion group and class Ⅱ malocclusion group. The subjects consisted of 50 normal occlusion(male 25, female 25) and 50 class Ⅱ(male 25, female 25) malocclusion patients. All subjects are adult. lateral cephalogram was taken with standard method, traced, and digitized for each subjects. The computerized statiscal analysis was carried out with SPSS program. The result were as follows: 1. In class Ⅱ malocclusion group, variables significant different from normal occlusion group were as follows; SN-FOP, FH-BOP, MP-BOP, AB-BOP, AB-FOP, Facial plane-BOP, FP-FOP. 2. In class Ⅱ malocclusion group, the posterior facial height -especially posterior lower facial height-was significantly smaller than normal occlusion group.(P<0.05) 3. In class Ⅱ malocclusion group, the angles between occlusal plane and upper and lower incisor, the angle between upper molar and bisected occlusal plane were significantly larger than those of normal occlusion group.(P<0.05) 4. L1 to Mandibular plane(mm) was a unique factor of occlusal plane position that showed that showed significant difference in class Ⅱ malocclusion group. 5. The correlation between overbite and occlusal plane inclination existed in class Ⅱ malocclusion group, but the correlation didn't exist in normal occlusion group.

과개교합자의 악안면 형태에 관한 두부 X-선사진 계측학적 연구

김희정,남동석 대한치과교정학회 1993 대한치과교정학회지 Vol.23 No.3

This study was investigated to evaluate the morphologic characteristics of deepbite tendency as multiple factors. The subjects consisted of 60 control subjects(male 25, female 35) and 137 deepbite patients(68 male, 69 female). The deepbite group was composed of 4 subgroups(Class Ⅰ 44, Class Ⅱ div. 1 40, Class Ⅱ div. 2 13, Class Ⅲ 40). The mean age was 21.57 year for the control group 21 year for deepbite group lateral cephalograph in centric occlusion were taken, traced, and digitized for each subject. The statistically computerized analysis was carried out with SAS program. The results were as follows ; 1. In deepbite group, saddle angle is lesser than that of normal group. 2. The vertical dysplasia is prominent on anterior lower face and is closely related with mandibular form and inclination. 3. Without consideration of sagittal relationship, the dental factors such as curve of Spee, interincisal angle, U1 to upper lip length were prominent in the deepbite group. 4. Although there were individual variances in the perioral soft tissue profile, the lip presented more protruded pattern. 5. There was no significant difference in hyoid bone position and inclination between normal and deepbite group. 6. The multivariate discriminant analysis between normal and Class Ⅰ deepbite group showed that curve of Spee, AB-MP angle, interincisal angle, articular agnle were critical in the determination of deepbite as multiple factors.