• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.491-491
• /
• 2013

A novel plasma system has been developed for 3-dimensional modification of the carbon nano-powders. Improvement of dispersion of these nano materials are studied by plasma discharge, not using chemical modification. The plasma process is considered to great advantages over wet chemical process due to environmental, economic viewpoint, and uniformity over the treated volume. The uniform dispersion is a critical factor for these material's nano composite applications. Using this plasma system, graphene, carbon black, and CNT was treated and functionalized. Several key discharge conditions such as Ar/H2/O2 or Ar/H2/NH3 gas ratio, treatment time, power, feeder's vibration frequency are investigated. Hydrophobic of graphene has turned some more into hydrophilic by reaction test with water, electrophoresis, surface contact angle test, and turbidity analysis. The oxygen content ratio in the plasma treated CNT has increased about 3.7 times than the untreatedone. In the case of graphene and carbon black, the oxygen- and nitrogen- content has been enhanced average 10%. O-H (N-H) peak, C-O (C-N) peak, and C=O (C=N) peak data have been detected by FTIR measurement and intensified compared to before-plasma treatment due to O2 or NH3 content.

• Steel and Composite Structures
• /
• 제19권5호
• /
• pp.1167-1184
• /
• 2015

Despite considerable life casualty and financial loss resulting from past earthquakes, many existing steel buildings are still seismically vulnerable as they have no lateral resistance or at least need some sort of retrofitting. Passive control methods with decreasing seismic demand and increasing ductility reduce rate of vulnerability of structures against earthquakes. One of the most effective and practical passive control methods is to use a shear panel system working as a ductile fuse in the structure. The shear Panel System, SPS, is located vertically between apex of two chevron braces and the flange of the floor beam. Seismic energy is highly dissipated through shear yielding of shear panel web while other elements of the structure remain almost elastic. In this paper, lateral behavior and related benefits of this system with narrow-flange link beams is experimentally investigated in chevron braced simple steel frames. For this purpose, five specimens with IPE (narrow-flange I section) shear panels were examined. All of the specimens showed high ductility and dissipated almost all input energy imposed to the structure. For example, maximum SPS shear distortion of 0.128-0.156 rad, overall ductility of 5.3-7.2, response modification factor of 7.1-11.2, and finally maximum equivalent viscous damping ratio of 35.5-40.2% in the last loading cycle corresponding to an average damping ratio of 26.7-30.6% were obtained. It was also shown that the beam, columns and braces remained elastic as expected. Considering this fact, by just changing the probably damaged shear panel pieces after earthquake, the structure can still be continuously used as another benefit of this proposed retrofitting system without the need to change the floor beam.

• 전산구조공학
• /
• 제9권4호
• /
• pp.229-237
• /
• 1996

구조물의 내진설계는 일반적으로 설계시방서의 스펙트럼을 이용하여 이루어지고 있다. 각 시방서에서 제시된 스펙트럼은 여러지역에서 발생한 지진파들을 최대 지반가속도로 정규화하여 평탄한 응답을 구하였으며, 구조물의 특성에 따라 증감하여 사용하고 있다. 구조물은 지진하중에 의하여 소성변형을 보이고 있으며, 이러한 구조물의 소성변형 능력을 고려하여 설계시방서에서는 응답수정계수를 사용하고 있다. 그러나, 이러한 응답수정계수는 모든 구조물의 고유진동주기에 대하여 일정한 값으로 사용되고 있다. 본 연구에서는 각각의 지진파에 대하여 20개의 인공지진파을 작성하여 평탄한 응답스펙트럼을 구하였다. 구하여진 평균 응답 스펙트럼을 사용하여 구조물의 초기항복강도와 감쇠율의 효과를 측정하였으며, 회기분석을 통하여 내진설계시 각 구조물에 요구되는 변위연성도를 얻기 위한 강도계수를 추정하였다. 또한 현재 사용되고 있는 설계시방서의 응답수정계수를 구조물 고유진동주기의 함수로 나타내었다.

• 대한지역사회영양학회지
• /
• 제8권4호
• /
• pp.477-484
• /
• 2003

This study was conducted to investigate nutrient intakes and obesity-related factors of obese children by interviewing the subjects aged from 11 to 13 in Daegu. The collected data were consisted of items on general characteristics, dietary behavior, nutrition knowledge and daily nutrient intakes of subjects. The subjects were classified into obese and non-obese control groups according to their relative weights. Frequency of skipping breakfast and eating rate of obese group were significantly higher than those of control group. There was no significant difference between obese and control group in the nutrition knowledge score. Except vitamins $B_1$, $B_2$ and iron, the average daily intakes of other nutrients in obese were greater than control group. The most contributing factor to BMI turned out to be cholesterol intake. After the nutrition education targeting obese children, their nutrition knowledge scores improved, but the dietary behavior score was not significantly changed. Therefore, childhood obesity may be prevented by continuous education programs including the behavior modification of obese children. (Korean J Community Nutrition 8(4) : 477-484, 2003)

• 한국방재학회 논문집
• /
• 제6권3호
• /
• pp.9-16
• /
• 2006

기존 대부분의 구조물 건전도 모니터링 시스템에서는 제한적인 위치와 범위에서의 변형률 계측이 가능한 국부 변형률 센서를 이용하여 구조물 또는 구조 부재의 부재력을 계측하고 이에 기반하여 구조 안전성을 평가하고 있다. 그러나 실 구조물의 부재력 계측을 통한 안전성 평가는 하중의 크기 및 분포에 대한 불확실성 등의 다양한 이유로 부재 내 최대응력 작용점을 정확하게 파악하기 어렵다. 이러한 경우 구조물의 사이즈에 비하여 센서의 길이가 미소한 국부 변형률 센서를 이용한 안전성 평가의 적절성은 센서의 위치 및 개수에 좌우되는 한계를 가지게 된다. 이러한 한계를 극복하기 위하여 센서의 수를 증가시키면 처리해야하는 데이터의 양과 비용이 증가하게 되므로 현실적인 적용성에 문제점을 가지게 된다. 그러므로 본 연구에서는 이러한 한계와 문제점을 극복할 수 있는 대안으로 장대광변형센서에 의한 평균변형률을 이용한 보-기둥의 부재력 계측 기법을 제시하였다.

• 재활치료과학
• /
• 제10권2호
• /
• pp.37-51
• /
• 2021

목적 : 본 연구는 주로 침흘림을 보이는 뇌성마비 아동에게 비침습적인 치료적 중재와 침흘림 측정방법의 경향 분석 등에 대한 국외 문헌들을 중심으로 종합적으로 분석하고자 하였다. 연구방법 : 본 연구는 최근 15년 간(2005-2019) 국외 논문을 검색하여 총 265편의 논문이 검색되었다. 1차 제목 및 초록을 중심으로 44편의 논문이 선정되었고, 2차 원문 검색을 통해 10편의 논문이 최종적으로 선정되었다. 결과 : 선정된 논문의 PEDro Scale은 평균 6점으로 높은 편이었다. 전반적인 동향을 분석한 결과 연구대상자는 뇌성마비가 주를 이루었고, 행동수정에 비해 구강감각운동의 치료적 중재가 최근에 활발하게 연구되고 있었다. 행동수정과 구강감각운동 중재방법은 대상자의 나이, 인지수준, 대상자 수, 연구설계, 치료시간과 기간에서 차이가 있음을 확인하였다. 침흘림 측정방법은 빈도와 심각성을 동시에 확인하는 연구가 주를 이루는 것으로 나타났다. 결론 : 본 연구에서는 침흘림을 보이는 뇌성마비 아동에게 실시한 비침습적인 중재 중 대표적인 행동수정과 구강감각운동 중재에 대해서 분석하였고, 이러한 자료를 통해 행동수정과 구강감각운동치료를 통한 침흘림 프로그램 계획 시 적절한 치료적 중재방법을 선택하는데 도움이 될 수 있는 정보제공 및 근거를 마련하였다.

• 한국정보과학회논문지:시스템및이론
• /
• 제34권11호
• /
• pp.599-609
• /
• 2007

플래시 메모리는 덮어 쓰기 제약이나, 쓰기와 삭제 연산의 단위가 다르다는 등의 특징을 가지고 있다. 따라서 플래시 메모리를 저장장치로 사용하는 파일 시스템은 블록 클리닝을 필요로 하며 이는 파일 시스템의 주된 병목으로 작용한다. 이에 따라 본 논문에서는 플래시 메모리 기반 파일 시스템의 병목 요소인 블록 클리닝에 따른 성능향상에 대해 연구한다. 우선 블록 클리닝에 영향을 끼치는 성능 인자로서 이용률, 무효율, 순수도를 정의하였다. 이 세 가지 인자를 통해 블록 클리닝 비용을 분석한 결과, 파일 시스템 수준에서 제어 가능한 인자인 순수도가 블록 클리닝 비용에 많은 영향을 끼침을 확인할 수 있었다. 따라서 순수도를 높게 유지하여 블록 클리닝 비용을 최소화함으로서 파일시스템의 성능을 향상 시킬 수 있는 MODA 할당 정책(modification-aware)을 설계하였고, 이를 내장형 보드와 YAFFS(Yet Another Flash File System)상에 구현하였다. 실험 결과 MODA는 YAFFS의 순차 할당 기법에 비해 블록 클리닝 시간을 평균 123% 단축 시켰다.

• 한국정밀공학회지
• /
• 제12권8호
• /
• pp.63-72
• /
• 1995

Closed-die forging of spur gears with hollow cylindrical billet has been analysed by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, an involute curve has been introduced to represent the forging die profile. In the analysis, the deformation region has been divided into nine zones. A constant frictional stress has been assumed on the contacting surfaces. Utilizing the formulated velocity field, numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth and friction factor, on the forging of spur gears. Hardness and accuracy of forged gears are measured. The following results have been obtained: (1) It is verified that an axisymmetric deformation zone exists between root circle and center of gear through forged gears. (2) The average relative forging pressure is predominantly dependent on the number of teeth and increases near the final filling stage as the addendum modification coefficient increases. (3) Close agreement was found between the predicted values of forging load and those obtained from experimental results.

• Clinics in Shoulder and Elbow
• /
• 제3권2호
• /
• pp.61-67
• /
• 2000

Purpose: Most proximal humeral fractures are minimally displaced and can be treated satisfactorily with a conservative method. But in many comminuted fractures, hemiarthroplasty is usually done as a primary treatment. The authors evaluated how much functional improvement was achieved after hemiarthroplasty and which factors influence on the final functional results. Materials and Methods: Eleven hemiarthroplasties were performed for three- and four-part fractures(including fracture-dislocation) between April 1992 and June 1999. There were eight women and three men, and the mean age was 65 years. According to Neer classification, six was three-part fracture and five was four-part fracture. Six patients were injured on their right shoulder and five on the left shoulder. Among the five four-part fractures, three had axillary nerve injury and among the six three-part fractures, only one patient had axillary nerve injury. The average follow-up period was 2.4 years(1 year-7 years) after operation. The functional results were evaluated with the UCLA scoring system(Modification for hemiarthroplasty). In addition to the overall results, we compared the results according to the classification of the fracture, the cause of injury, and whether the axillary nerve was injured. Results: At the last follow-up, average total UCLA score was 18.2. The mean score for pain was 7.0, mean muscle power and motion score was 5.5 and 5.7 respectively. The pain relief was more satisfactory than any other functional results. The average score for three-part fractures was 22, and the average for four-part fractures was 13.6. The average score for the patients fractured by vehicle accidents was 15.3, and 19.3 for the patients fractured by slip-down injury. In patients without axillary nerve injury, the average score was 20, and with axillary nerve injury, the score was 15. Conclusion: Shoulder hemiarthroplasty, for the treatment of proximal humeral fractures, cannot restore the shoulder function to normal, but can achieve the functional result to some degree, especially for the activity of daily living. And as for pain, we think that it is relatively effective measure. And we think that the severer the comminution, the more the chance of axillary nerve injury, and the poorer the functional results. In conclusion, the severity of initial injury seems to be the major prognostic factor.

• 대한간호학회지
• /
• 제26권2호
• /
• pp.359-371
• /
• 1996

This study has been done for the purpose of testing the effect of health education on the performance of health promoting behavior in college students, and identifying the factors affecting health promoting behaviors. A Nonequivalent control group posttest research design was used. Two hundred thirty college students at K College in T city were studied. Of them, 114 who attended a systematic health education session for three hours a week during one semester were the experimental group. And 116 college students who were chosen of matched sampling of grade, class and sex were the control group. This study was conducted from March 1 to July 2, 1995. The instruments used for this study included a survey of general characteristics, perceived health status, self-esteem, health promoting behavior and health locus of control. Analysis of data was done by use of mean, 1-test, Pearson correlation coefficient and multiple regression. The results of this study are summarized as follows : 1) The average item score for the health promoting behavior was low at 2.52. In the sub-categories, the highest degree of performance was ‘harmonious relationships’, following ‘sanitary life’, ‘self-esteem’, ‘rest and sleep’, and ‘emotional support’ and the lowest degree was ‘professional health management’. 2) Hypothesis 1 that the college students who get health education will have a higher degree of health promoting behavior than the college students who do not get health education was accepted. There was a statistically significant difference between the average of the experimentalgroup, 2.60, and the average of the control group, 2.45.（t＝11.30, p＝0.0009）. 3) Hypothesis 2 that the college students who get health education will have a higher score of perceived health status than college students who do not get the health education was rejected. （t＝1.13, p＝0.289） 4) Performance of health promoting behavior was positively correlated with self-esteem and grade and negatively correlated with perceived health status. 5) The most important factor affecting performance of health promoting behavior was self-esteem. The following suggestions are made based on the above results : 1) Replication of the research is needed to confirm effects of health education. 2) More effective health education programs need to be developed through by modification of teaching methods and content analysis of health education. 3) Other factors affecting health promoting behavior should be identified. 4) Nursing colleges or departments of nursing should make an effort to develop and carry out various health education programs for the health promotion of all college students.