Flexible Optoelectronics: Flexible Inorganic Nanostructure Light‐Emitting Diodes Fabricated on Graphene Films (Adv. Mater. 40/2011)

Lee, Chul‐,Ho,Kim, Yong‐,Jin,Hong, Young Joon,Jeon, Seong‐,Ran,Bae, Sukang,Hong, Byung Hee,Yi, Gyu‐,Chul WILEY‐VCH Verlag 2011 ADVANCED MATERIALS Vol.23 No.40

<P>Inorganic‐based flexible light‐emitting diodes (LEDs) using single‐crystalline GaN/ZnO coaxial nanorod heterostructures grown directly on large graphene films are reported on page 4614 by Gyu‐Chul Yi and co‐workers. The LEDs demon‐strate reliable operation in a flexible form, with no significant degradation in their electroluminescent or electrical characteristics. This approach provides a general and rational route to develop many different inorganic optoelectronics in flexible or stretchable forms. </P>

Graphene: Position‐ and Morphology‐Controlled ZnO Nanostructures Grown on Graphene Layers (Adv. Mater. 41/2012)

Kim, Yong‐,Jin,Yoo, Hyobin,Lee, Chul‐,Ho,Park, Jun Beom,Baek, Hyeonjun,Kim, Miyoung,Yi, Gyu‐,Chul WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.41

<P>On page 5565, Gyu‐Chul Yi and co‐workers grow position‐ and morphology‐controlled ZnO nanowalls in prescribed positions on graphene layers. The nanowalls are grown to produce a variety of shapes from simple circles to text at the microscale. The selective growth of high quality ZnO nanowalls is investigated by electron microscopy and optical spectroscopy. The hybrid nanostructure can be exploited to fabricate various nanodevices including microarrays of nanotube LEDs. </P>

관동맥질환에서 저밀도 지단백 입자 크기의 분포

임효영,김인숙,승기배,강동헌,전두수,장기육,박준철,이수영,홍순조,최규보 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.8

수리실험을 통한 호안재료별 흐름저항 특성 연구

유규석,김철 호남대학교산업기술연구소 2011 산업기술연구논문집 Vol.17 No.-

최근 하천사업에는 자연친화적인 설계기법이 도입되고 있으며 호안공법도 과거 제방보호 기능만을 가진 단순한 호안에서 식생을 활용한 다양한 종류의 호안공법이 개발되어서 각종 하천공사에 도입되고 있다. 따라서 호안공법을 도입할 때 호안재료에 따른 유수의 흐름이 하천의 흐름에 미치는 영향을 파악하는 것은 하천설계에 있어 대단히 중요하다. 이에 본 연구에서는 각기 다른 호안재료별로 유속분포, 레이놀즈수, 마찰계수를 산정하여 흐름특성을 파악하고 호안에 대한 적용성 및 호안재료의 수리학적인 평가를 위한 자료 확보에 초점을 두어 수리실험을 수행하였다. 실험에 사용된 호안재료는 토양, 호안블록, 인공식생, 실제식생인 잔디와 갈풀을 이용하였으며, 실내 개수로 실험 장치를 이용하여 유량의 변화에 따라 실험을 실시하였다. 수리실험결과 무식생인 블록과 토양은 바닥으로부터 수면까지의 유속의 변화가 작은 동일한 양상을 보이는 반면, 식생은 바닥으로부터 식생높이까지의 식생영역부분과 식생상단으로부터 수면까지 유속의 분포가 다른 양상을 나타내었다. 식생이 있을 때 무식생 호안재료에 비해 하상으로부터 식생높이까지는 유속이 감소하였고, 식생 상단으로부터 수면까지는 무식생 호안재료에 비해 유속이 증가하는 양상을 나타내었다. 마찰계수 분석결과 토양과 블록은 비슷한 결과를 나타내었지만, 식생은 재료의 상단과 하단부에서 각기 다른 양상을 나타내었다. 다른 재료에 비해 식생의 상단에서는 마찰계수가 감소하였고, 하단부에서는 마찰계수가 증가하였다. 이로부터 식생영역 하단에서 유속의 감소로 인한 하상의 침식과 사면의 보호에 식생이 충분한 효과를 발휘할 수 있다는 사실을 증명하였다. The nature-friendly design techniques are recently being introduced in river projec-ts and various bank protection revetment techniques which are using the vegetation have also been developed and introduced. The simple bank revetment method which has the only bank protection function has been used in the past. But understanding the effect of water flow in the river is a crucial part in the river design. Therefore the tests have executed for the characteristics of flow by calculating velocity distribution, Reynolds number and friction factor against bank materials and gathered data for the applicability to the bank revetment and the hydraulic assessment of materials. The materials used for the experiment are bare soil, revetment blocks, artificial herbaceous plants, and real herbaceous plants such as lawn grass and Phalaris arundinacea and the vertical velocity distribution was measured by changing flow in the open channel experiment instrument inside. According to the results of the research, it is identified that bare soil and revetment blocks are showed a similar appearance with a little flow velocity changing but vegetation is showed different velocity distributions between surface and the top of vegetation, between the top and bottom of vegetation. In vegetation, it is shown that flow velocity is decreasing between riverbed and the top vegetation and is increasing between the top vegetation and surface against non-vegetation. By result of friction factor experiments, bare soil and revetment blocks appeared a similar outcome but vegetation have different figures at top and bottom of material. The friction factor is decreasing at the top of vegetation compared with the other materials and is increasing at the bottom of vegetation. it was proved that the vegetation is helpful to slope protection and riverbed erosion by decreasing of flow at bottom of vegetation area.

사업장 근로자의 건강위험 평가도구 개발

홍윤철,임현술,하은희,정규철,조희숙,박혜숙,이용애 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4

Health Risk Appraisal(HRA) is usually defined as a process by which we expect of individual's chances of death or acquiring specific diseases within a defined period of time. The concept of worksite as an area of health maintenance and promotion is newly developing. Our movement for health promotion of employees has been increasingly known in the worksite. The aim of this study is to develop health risk appraisal tools about health promotion at the worksite for employees. We performed this study by two steps; one step was to develop a HRA questionnaire of worksites in Korea, another was to evaluate the reliability of the questionnaire. For developing HRA questionnaire, we reviewed scientific examples at first, and then weighted the score by delphi. To evaluate the reliability of developed questionnaire, we carried out survey by test-retest method. A total of 131 employees completed HRA questionnaire on two times. The results are as follows. The total score of health risk in unhealthy workers was higher than that of healthy workers. The range of test-retest reliability of responses to the questionnaire was 0.57-0.94. Therefore it seems that this questionnaire was very suitable to assess the health behavior of workers. In conclusion, the developed HRA questionnaire can be used as a tool for evaluating health behavior and for providing health counseling materials.

정신과 입원환자의 서비스 만족척도의 개발

김철권,이지연,송영선,김규호,김경률,김제원,이동기,최병무 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.3

목적 본 연구의 목적은 국내 정신의료기관(정신병원, 종합병원 정신과)에서 간편하게 사용할 수 있는 신뢰도와 타당도가 검증된 입원환자의 서비스 만족척도를 개발하기 위한 것이다. 방법 여러 단계를 거쳐 국내 실정에 맞는 문항을 개발하였고,정신병원, 종합병원, 대학병원 정신과 병동에서 퇴원하는 348명의 환자들을 대상으로 신뢰도와 타당도를 조사하였다. 요인분석 결과 5개의 요인이 추출되었으며 전체 변량의 63.04%를 설명하였다. 내적 일관성에 대한 신뢰도 계수 (Crohnbach's α)는 0.95로 상당히 높은 수준이었고, 수정된 개별문항-총점 상관계수는 0.50부터 0.72까지의 범위에 속하였다. 요인분석을 통해 추출된 서비스 만족척도의 각 하위척도 점수와 서비스 만족척도에 첨부된 각 영역에 대해 전반적인 만족도를 묻는 세 개의 문항 점수 간의 상관성 역시 유의하게 높았다. 결과 진단명에 따른 서비스 만족척도의 전체 점수에서는 불안/신체형/강박장애 환자군과 기분장애 환자군이 각각 정신분열병 및 기타 정신병 환자군과 알코올중독 장애 환자군에 비하여 유의하게 높은 점수를 보였으며, 입원형태에 있어서는 자발적 입원군이 강제 입원군에 비하여 전체 만족점수가 유의하게 높았다. 그러나 성별, 월수입, 학력, 직업, 종교, 결혼상태 등의 변수에서는 서비스 만족척도의 전체 점수에서 유의한 차이가 발견되지 않았으며, 마찬가지로 연령, 입원일수, 입원횟수, 첫 발병나이, 유병기간 등의 임상적 변수에서도 서비스 만족척도의 전체 점수와 유의한 관계를 보이지 않았다. 서비스 만족척도의 전체점수에서 대학병원 환자군이 정신병원 환자군과 종합병원 환자군에 비하여 각각 유의하게 높았다. 결론 결론적으로 국내 정신의료기관에 입원한 환자들의 서비스 만족을 평가하기 위한 목적으로 개발된 본 척도는 높은 수준의 신뢰도와 타당도를 보였으며, 또 국내 정신의료 환경에 맞는 요인구조를 보였다. 따라서 정신의료 서비스에 대한 정신과 환자의 만족도에 대한 연구가 거의 없는 실정에서 본 척도의 개발은 향후 국내 정신의료의 질과 치료결과를 높이는 도구로 활용될 수 있을 것으로 기대된다. Objectives : To develop and test the validity and reliability of a brief self-completed questionnaire (Service Satisfaction Scale : SSS) for routinely assessing the quality of service in psychiatric ward inpatients. Methods : A 30-item multidimensional questionnaire was developed by several steps of face validity and content validity. The questionnaire was administered to inpatients (n=348) discharged from psychiatric hospitals, general hospitals, and University hospitals. Construct validity was supported by performing principal component analysis. Reliability was estimated by calculating internal consistency of Cronbach's alpha. Results : Factor analysis yielded five factors comprising staff attitude, treatment quality, ward environment, access/cost, and ward rule, which account for 63.04% of the common variance. The internal consistency of the scale was high (Cronbach's alpha=0.95). The concurrent validity was supported by the significant correlation of each of five factors with item that measured overall satisfaction of SSS. Patients with neurosis (anxiety disorder, somatoform disorder, obsessive compulsive disorder) and mood disorders were significantly satisfied than those with psychosis and alcoholic disorders. Patients who admitted voluntarily were more significantly satisfied than those who admitted involuntarily. Sociodemographic variables such as age, gender, marital status, monthly income, education level, employment status and religion were not significantly different at the total scores of SSS. Similarly, clinical characteristics such as age of onset, duration of illness, lengths of hospital stay and number of previous hospitalization did not associate significantly with the total scores of SSS. Patients discharged from university hospitals were significantly more satisfied than those of the general and psychiatric hospitals. Conclusion : SSS performed well in the validity and reliability, indicating that it can be a useful tool for measuring Satisfaction of psychiatric inpatients in Korea.

국내 지역사회 거주 노인의 다면적 낙상예방프로그램에 대한 메타분석

김철규 청주대학교 보건의료과학연구소 2013 보건의료과학연구 Vol.2 No.1

The purpose of this study was to evaluate the effects of multifactorial fall intervention programs for elderly living at home in Korea. Four studies for meta-analysis were extracted from electronic databases through KERIS, KISS, and DBpia. The selected studies were nonequivalent control group pretest-posttest design and published peer reviewed articles. The effect sizes for multifactorial fall intervention programs were significant with ES=1.41 for balance, ES=0.72 for gait ability, and ES=-7.70 for fear of falling. The analysis of studies indicates that the multifactorial fall intervention programs is effective in improving balance, gait ability and fear of falling for elderly living at home in Korea.

TiAIN 코팅공구를 사용한 Ti-6Al-4V 티타늄합급의 절삭특성에 관한 연구

이승철,박종남,조규재 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

The Titanium has many superior characteristics Which are specific strength, heat resistance, corrosion resistance, organism compatibility, non-magnetic and etc. and their quantity are abundant.this study performed turning operation of Ti-6AI-4V alloy using the TiAIN Coate Tool which treated PVD (Physical Vapor Deposition). Experimental works are also executed to measure cutting force, chip figuration and surface roughness for different cutting conditions. As a result of study. Tool wear was serious at over 100m/min of cutting speed and cutting condition was excellent at 1.0㎜ of cutting depth.

자동차의 후방 스포일러(Spoiler)가 주행 안정성에 미치는 공기역학적 영향에 관한 수치 해석적 연구

김철호,윤동규,이창민 서울産業大學校 1998 논문집 Vol.47 No.1

Even though an automotive industry has its long manufacturing history, its design and manufacturing technology is mainly based upon the empirical background. Along with the rapid development of the calculating machine a theoretical approach on the research and development in many industrial areas is now tried to for the better research output because the theoretical approach has many advantages compared with the experimental method. In here a theoretical study has been done to understand the effect of the spoiler attached on the booth of the small & medium size sedan on the dynamic geometry such as spoiler attached angle(αs),location, chord, span, etc., the optimized configuration of the spoiler which is well matched to the certain model of a car can be designed. However if the improperly designed spoiler is attached on a car, it may require higher fuel consumption rate because of the higher drag force and in case, have lower controllability of the car because of the higher lift force induced by the mismatched spoiler. For this study, Navier-Stokes equations with the standard (κ-ε) turbulent model was solved. Car running speed(Ucar), spoiler attached angle(αs) were selected as the main parameters. Variation of the drag force (form drag and induced drag) and lift force were analyzed to understand the effect of the spoiler on the dynamic stability and fuel consumption rate of the model cars.

離散型計劃法에 의한 鐵筋 Concrete 斷面의 最適化에 관한 硏究

鄭哲源,최규도 圓光大學校 1987 論文集 Vol.21 No.2

本 硏究는 一連의 設計制約을 받는 構造物 系의 各 成分이 fixed set에서 選擇되어 질때 그 系를 最適化하는 數學的計劃法을 敍述하고 있다. N次 制約空間의 幾何學的 形象에 대한 解析이 만들어 지고, 그 解析節次는 制約空間에서 目的函數平面을 移動시킴으로써 考案된다. 目的函數를 移動시키는 것은 設計變數가 미리 規定한 範圍에서 選擇되어 질 때 그 問題에 대한 最適解를 決定하기 위해서다. 더욱 進步된 探索過程에서 幾何學的 묘사가 敍述되어 있으며, 그에 대한 數學的 公式이 表現되어 있다. This study presents a mathematical programming method by which a designer can optimize a system of components when the system is subjected to a set of design constraints and the individual components must be picked from a fixed set. An analysis of the geometric configuration of an N?? order constrained space is made and a procedure is devised by which an objective function plane can be translated through this space in a controlled manner. The controlled translation of an objective function is for the purpose of determining the optimum solution to a problem when the variables must be selected from some pre-defined set. A geometrical description of the developed search routine is given and is supported with a mathematical description.