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.

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.

건설현장 근로자들의 안저예방실태와 사고예방과의 개선요인 조사연구

심규범,남철현,최상복,이송권,이정희,이순자,문기내,김문환 慶山大學校 保健福祉硏究所 2003 保健福祉硏究 Vol.8 No.-

This study was conducted to examine aspects of health and safety education and demand level of safety education in construction job sites in order to provide direction of safety education development. The subjects of this study were 566 workers who were working in construction job sites located in Daegu City and Kyungbuk Province. Data were collected from June 1, 2002 to August 30, 2002. The results of this study can be summarized as follows. 1. According to safety education by experience methods, the proportion of education by lecture was highest (90.6%). The proportion of education by field practice was 13.1%. 2. Among the education methods which they thought as the most desirable method, the proportion of audio-visual education was 39.4% and the proportion of education by experience was 37.5%. Those who had more monthly income and higher education level preferred audio-visual education, while those who were younger and less educated preferred education by experience. 3. In the case of the contents of the safety education which they thought as the most important one, the proportion of enhancement of safety awareness and education of risk factors was highest (24.7%). The groups of older workers, having longer working period, and belonging to higher education level preferred these contents. 4. According to the factors which were most important to increase effectiveness of the safety education were workers' voluntary participation (27.7%), 40 to 49 years old (27.7%), and monthly income of one million, five hundred thousand won to one million, nine hundred ninety thousand won (32.0%). The proportions of lower educated workers and working as daily workers were also high. 5. The variable which most influenced the safety education was age. The safety awareness of construction job sites was the second highest influential variable. From above results, it is clear that the workers' participation in the safety education was low since most of the safety educations were formal education by lecture. Although they participated in the education, the education was also not effective because they compulsorily participated in it. Therefore, it can be concluded that effective alternative policies must be formulated.

煉炭工場 勤勞者의 塵肺症 發生과 肺換氣能에 關한 硏究

李忠揆,金光鍾,車喆煥 고려대학교 의과대학 1985 고려대 의대 잡지 Vol.22 No.1

A briquet is a source of major energy for heating and cocking in the common households in Korea. For its production, a total of 2,000 workers are employed in 17 briquet factories in Seoul Korea, where they are heavily exposed to the coal dust while working. In this study ail attempt was made to analyze and evaluate the prevalence of pneumoconiosis among 152 coal workers and the ventilatory function in two briquet factories. Also, concentrations of total and respirable dust in The working environment were investigated. To obtain the amount of respirable dust, the total amount of dust in the air of each working place was measured and analyzed based on the size of particles. To determine the prevalence and type of pneumoconiosis, radiographic examinations and pulmonary function test were performed on each workers. The results are as follows: 1. The average concentrations of total and respirable dust in working places of two factories were 16.1mg/㎥ and 10. 2mg/㎥ respectively, both of which are greater than the threshold limit value. The concentrations of the total dust in each section of the factory also were beyond the TLV. The distribution of particles less than 7μ was about 60% of the total amount of dust. 2. The career history of the examines revealed the 5~9 service year group as the largest, with 51 out of 152 workers (33.6%). By the age group, 40~49 year was the largest, 82 out of 152 workers (53.9%). 3. The results of the radiographic examinations showed that 24 workers with pneumoconicsis were advanced to category 1, 2 and 3 with a prevalence rate of 15.8%. The prevalence rate showed a tendency ta increase remarkably in accordance with the age and the number of working years. 4. In case of pneumoconiosis in category 1 , 2 and 3, a high correlation between the age and the number of working years was seen (r=0.547, p<0.01). 5. In the distribution of pneumoconiosis by grade, category 2 was 54.1% of all the cases, category 1, 41.7% and category 3, 4.2%. 6. The %FEV_(1.0) and MMEF of cases were less than that of the normal group. 7. Among the workers exhibiting pneumoconiosis as determined by ventilatory function test, 25% were of obstructive type, 4.2% restrictive type, and 70.8% normal.

새로운 다중 전류원 인버어터의 개발

유철로,김홍규,이공희,이성룡 全北大學校 1992 論文集 Vol.34 No.-

A new multiple current source inverter for reducing the harmonics in output current is presented in this study. Condenser capacity necessary for the inverter design is decided by the commutation analysis of current source inverter with induction motor as load. And the proposed system operates 24 phase inverter by adding only tap changing circuit which consists of several taps and static switching elements to the 12 phase inverter, which is the double connected 6 phase inverter with an interphase reactor. Also to optimize the effectiveness of the harmonic reduction, the optimum turn ratio and tap changing control angle of interphase reactor are decided by digital simulation and its validity is verified with experiment. And under the optimum condition, it is clarified that the harmonics components involved in the output currents of the proposed inverter are nearly equal to those of the conventional 24 pulse inverter.

합성수지의 접합

정규창,이철구 서울산업대학교 산업대학원 1996 大學院論文集 Vol.4 No.-

The joining of polymer materials can be mechanically fastened or adhesively bonded, but they can also be welding. Mechanical fastening is an expensive multistep operation which creates stress concentrations in the part. It provides good assurance for the quality and strength of the joint. Adhesively bonded joints have more uniform load distributions than bolted joints. Surface preparation for good wetting of the adhesive is very critical to the process. Inspection of the bond is usually required. Welding or fusion bonding is restricted to polymer materials only, and it requires heating and melting of the thermoplastic. Welded joints, like adhesively bonded joints, have more uniform load distribution than bolted joints. At present, inspection of the welded joint is usually required, however closed loop controls should soon eliminate that requirement. The theory and practice behind joint design and the use of mechanical fastening, adhesive bonding, and welding are discussed.

노인외상환자의 예후 인자

문철규,전정민,최성혁,문준동,이성우,홍윤식 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: It has been documented that certain prognostic factors may affect the outcomes of the old aged victims by trauma. Considering that trauma is the sixth most common cause of death in people over the age of 65 years and there is a rapid growth of elderly population, it is paramount to understand the prognostic factors when dealing with geriatric trauma patients. Hypothesis and Goals: It can be hypothesized that the prognostic factors should be determined independently between populations being consisted of different races, countries, socio-economic states, cultures, or so on. Thus, the study was designed to evaluate the factors affecting the outcomes of elderly Korean trauma patients. Methods: One hundred forty six patients aged over 65 years were retrospectively reviewed, who visited the Emergency Center of Korea University from January, 1997 to June, 1998. Of 146 patients, 7 were excluded due to discharge against advice or transfer to the other hospitals. Parameters analyzed were age, sex, mechanism of injuries, body region injured, Injury Severity Score (ISS), previous medical illness, hospital morbidity, duration of hospital stay, and cost. Each patient was classified into improved or not-improved group depending on the outcomes, and young-old or old-old group depending on the age. The factors affecting the hospital stay in improved patients were analyzed in the parameters of previous medical illness, hospital morbidity, multiple injuries, ISS, and age. All statistical tests were conducted with two-tailed levels of 0.05. Results: Of 139 patients, the mean age was 74±7.1 years, mean ISS 9.3±7.26, mean hospital stay 27±27.1 days. Most commonly injured body region was the extremities due to fall from a level surface. Rate of previous illness showed 0.94 medical diseases per person and were aggravated after trauma in 39 patients (60.9%). Hospital morbidity rate was 0.46 incidents per person. There were no differences in age and duration of hospital stay between the improved and the not-improved group. Substantial differences were noted in affected body region, incidence of previous illness, and hospital morbidity between the groups (p=NS). Not-improved group had higher ISS(p<0.05). ISS, previous illness and hospital morbidity affected the duration of hospital stay in the improved group. Hospital stay was 40±25.1 days in patients with ISS over 6 while 6±8.6 days in those with ISS 5(p<0.05). Hospital stay in the improved was 26±26.9 days while 31±24.8 days in the improved old-old group (p=NS). Hospital stay in the young-old minor trauma (ISS5) patients with previous illness and hospital morbidity was 26±10.1 days while 4±7.3 days in those without previous illness and hospital morbidity (p<0.05). Conclusion: Previous medical illness and hospital morbidity, not age, are predictive of outcomes of geriatric trauma patients with respect to hospital stay. As most of the hospital morbidity was a trauma-induced aggravation of previous medical illness and hospital morbidity contributing poor outcomes can be potentially avoidable, routine aggressive care for the geriatric trauma patients with previous medical illnesses is needed.