• Title/Summary/Keyword: material design

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Study on Electrical Resistivity Pattern of Soil Moisture Content with Model Experiments (토양의 함수율에 따른 전기비저항 반응 모형 실험 연구)

  • Ji, Yoonsoo;Oh, Seokhoon;Lee, Heui Soon
    • Geophysics and Geophysical Exploration
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    • v.16 no.2
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    • pp.79-90
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    • 2013
  • Geophysical investigation in non-destructive testing is economically less expensive than boring testing and providing geotechnical information over wide-area. But, it provides only limited geotechnical information, which is hardly used to the design. Accordingly, we performed electrical resistivity experiments on large scale of soil model to analyze the correlation between electrical resistivity response and soil water contents. The soils used in the experiments were the Jumunjin standard sand and weathered granite soil. Each soil particle size distribution and coefficient of uniformity of experimental material obtained in the experiments were maintained in a state of the homogeneous. The specifications of the model used in this study is $160{\times}100{\times}50$(cm) of acrylic, and each soil was maintained at the height 30 cm. The water content were measured using the 5TE sensors (water contents sensors) which is installed 7 ~ 8 cm apart vertically by plugging to floor. The results of the resistivity behavior pattern for Jumunjin standard sand was found to be sensitive to the water content, while the weathered granite soil was showing lower resistivity over the time, and there was no significant change in behavior pattern observed. So, it results that the Jumunjin standard sand's particle current conduction was better than the weathered granite soil's particle through contact with the distilled water. This lab test was also compared with the result of a test bed site composed of similar weathered soil. It was confirmed that these experiments were underlying research of non-destructive investigation techniques to improve the accuracy to estimate the geotechnical parameter.

Analysis of Tack Properties of Aramid/Phenolic Prepreg (아라미드섬유/페놀수지 프리프레그의 Tack성 분석)

  • Hong, Tae Min;Lee, Ji Eun;Hong, Young Ki;Lee, Jung Soon;Cho, Dae Hyun;Lee, Seung Goo
    • Journal of Adhesion and Interface
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    • v.14 no.3
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    • pp.117-120
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    • 2013
  • The prepreg material is a sheet of the reinforcement pre-impregnated with a resin. In this study, two types of prepreg were prepared with a general phenolic resin and the polyvinyl butyral (PVB) modified phenolic resin, respectively, with resin content of 40 wt%. After resin impregnation, the prepregs were heat treated in an oven to make them the B-stage. Surface morphology of the prepreg was observed by using a scanning electron microscope (SEM). Tack property of the prepreg is one of the major properties that govern the ability of prepreg to be laid up. In this study, the tack of prepreg was measured under various test parameters by a probe tact test. Test parameters were contact time, contact force and debonding rate. Most of the tack properties of the prepreg increased with the test parameters. Then tack properties exhibited a linear behavior with test parameters before a saturation point. Also, the tack of prepreg was investigated in relation with the fibrillation phenomena involved in the prepreg surface with the debonding rate.

Improvement of The National Technical Qualifications System from ICT point of view (ICT 관점에서 바라본 국가기술자격제도 개선)

  • Chang, Jin-Hyeon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.2
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    • pp.189-199
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    • 2016
  • Pending issues present in the Nation Technical Qualifications System (NTQS) have been discussed to deal with the causes and improvements of the issues. The key present situations of the NTQS were investigated to analyze the problems of the NTQS. The acquisition distribution of the items of additional points in employment and the items applied to the laws and regulations of duty employment was revealed to be related with preferential items. The AHP analysis has been conducted based on issues for improvement of the NTQS raised till now. The urgency priority of the elements to be improved was ranked according to the AHP analysis result. The agendas for the improvement of the NTQS was suggested by consideration of the priority of the elements. First, a solution to raise discrimination of the NTQS was suggested by taking the view points of the experts into account. Second, an opinion was proposed that the preferential policies in employment should be directed toward expansion of qualification for duty employment. Third, two ideas were proposed to rectify problems embedded in the technician career handbook system. And four remedies have been made suggested, including the merger of similar events. The results of this research are expected to serve as a useful material for the future design of the NTQS.

Evaluation of Anti-Smoking Public Relations Messages -An Exploratory Study On the Effects Using Televised Health Messages- (금연홍보 캠페인의 메시지 효과평가 -영상홍보물을 이용한 탐색적 연구-)

  • Lee, Cheol-Han
    • Korean journal of communication and information
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    • v.44
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    • pp.223-247
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    • 2008
  • The purpose of this study is to explore the anti-smoking message effects and smoking status on smoking belief attributes. Based on the health behavior theories such as theory of reasoned action, health belief model, and social cognitive theory, three factors are selected to investigate the effects of anti-smoking campaign messages. The balance of benefits and barriers, self-efficacy, and social pressure are selected as independent variables. Three two-way ANOVA were conducted. Results showed that the main effect of social pressure were found with the social smoking attributes. Interaction effects were found on the nonsmoker-social pressure group and the non-smoker-two sided message group. It is found that nonsmokers accepted these two anti-smoking messages easily as compared to smoker groups. No main smoking status was found in this study; it is believed that smoking is a habitual that is not changed easily because attitude formation takes time. Results revealed that the two-sided message video releases and the social pressure video releases were favored by both smokers and nonsmokers. This study contributes the theoretical framework that can be transferred to the practices of anti-smoking campaign. Also, the researcher produced the televised stimuli which is not common in health message studies. By using the televised message material, the research tried to solve the validity problem which is common in experimental design.

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Effect of the Structured Education for Knowledge of Hepatitis B Type and Self Care Behavior in Chronic Hepatitis B Patients (구조화된 환자교육이 만성 B형 간염환자의 B형 간염에 관한 지식과 자가간호 수행에 미치는 효과)

  • Eum Sun-Ja
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.5 no.1
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    • pp.65-79
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    • 1998
  • The purpose of this study was to identify the effect of structured patient education on knowledge of Hepatitis B type and behavior about self care in chronic hepatitis B patients, and to fine the strategy to promote their self care behavior. The research design was quasi-experiment research. The study method had been done by investigating the experimental group and control group through the questionnaire on 50 patients who had been out patient medicine department in U university hospital in Ulsan from september 1st 1997 to the end of October, 1997. The analysis of the collected material had been done for the homogeneity test in which general characterics of experimental group and control group had been tested by $x^2-test$ and the homogeneity test of the knowledge of hepatitis B type and self care behavior before by t-test. To test the hypothesis the t-test had been given for the difference of the knowledge of hepatitis B type and self care behavior between the two groups and the correlation between knowledge of hepatitis B type and self care behavior performance had been tested by Pearson's correlation coefficient. The results as follows : 1. The 1st hypothesis 'The experimental group which received the structured education should be higher in the knowledge of hepatitis B type than the control group' was supported(t=-6.25, P=.000). 2. The 2nd hypothesis 'The experimental group which received the structured education whould be higher in the self care behavior performance than the control group' was supported(t=-5.15, P=.000). 3. The 3rd hypothesis 'The higher the knowledge of hepatitis B type in the patient the higher the self care behavior performance degree' was supported(r=.492, P=.001). In conclusion, the patients who received the structured education showed the increase in the degree of knowledge of hepatitis B type and self care behavior performance. so the structured education had been judged the nursing intervention had been prerequisite in increasing knowledge of hepatitis B type and self care behavior performance of the chronic hepatitis B patients.

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A Study on the Effect on the New Teaching Strategy Facilitating Reflective Thinking in the Learning of the Particulate Nature of Matter (물질의 입자성 학습에서 반성적 사고를 촉진시키는 새로운 입자모델 교수전략의 효과 - 초등학교 예비교사를 대상으로 -)

  • Kim, Do Wook
    • Journal of the Korean Chemical Society
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    • v.44 no.6
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    • pp.600-610
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    • 2000
  • The purpose of this study was to design the new teaching strategy based on the particulate model facilitating the reflective thinking (RE-PM) in the learning of the particulate nature of matter, and to investigate the effect of the new teaching strategy in compare with the traditional teaching strategy (TS-PM) after treating with new teaching strategy on preliminary teachers of elementary school. The problems of traditional teaching strategy are as follows: 1) Most of students didn't think the particulate model connected with practical material. 2) Most of students have a tendency of the rote memory on learning of the traditional particulate model. 3) The ratio of changing the view of continuous matter into the view of particulate nature of matter was very low, after learning the particulate model using of the traditional teaching strategy. The new teaching strategy facilitating the reflective thinking was more effective on the understanding of particulate nature of matter and the driving of motivation than the traditional teaching strategy in the learning of the particulate nature of matter.

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Fracture Behaviour Analysis of the Crack at the Specimen with the Type of Mode I Composed of the Bonded Carbon Fiber Reinforced Plastic (접합된 CFRP로 구성된 Mode I형 시험편 크랙의 파괴 거동 해석)

  • Lee, Jung-Ho;Cho, Jae-Ung;Cheon, Seong-Sik;Kook, Jeong Han
    • Composites Research
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    • v.28 no.6
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    • pp.356-360
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    • 2015
  • In this paper, the carbon fiber reinforced plastic is processed as the double cantilever beam in order to estimate the fracture behavior of composite and is carried out with the static analysis as the mode I. The specimen sizes are 25 mm, 30 mm, 35 mm and 40 mm. And the material property is used with carbon. As the analysis result of mode I, the adhesive part is detached latest by the small force at the specimen thickness of 25 mm. The largest force is happened at the specimen thickness of 40 mm. The defection of the adhesive interface is shown slowest at the displacement of 9.75 mm at the specimen thickness of 25 mm. And the defection is shown quickest at the displacement of 7.82 mm at the specimen thickness of 40 mm. This defection is due to the fracture of specimen. The result of this study on the defection of the adhesive interface and the reaction force due to this defection is thought to be contributed to the safe structural design of the carbon fiber reinforced plastic.

Joint Design and Strength Evaluation of Composite Air Spoiler for Ship (선박용 복합재 에어 스포일러의 체결부 설계 및 강도 평가)

  • Pi, June-Woo;Jeon, Sang-Bae;Lee, Guen-Ho;Jo, Young-Dae;Choi, Jin-Ho;Kweon, Jin-Hwe
    • Composites Research
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    • v.28 no.4
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    • pp.219-225
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    • 2015
  • Air spoiler, which can reduce the drag during operation, can be considered as a possible means to reduce carbon dioxide emission and to increase fuel efficiency. In this study, a composite air spoiler was designed and tested by static and repeated loads. The Green Water Pressure of 0.1 MPa a ship experiences during operation was perpendicularly applied to the air spoiler. Air spoiler was manufactured with sandwich panel which has glass fabric face and balsa core. Multiple sandwich panels were assembled to steel frame by bolt joint. The joint was designed to have bearing failure and examined by static and fatigue tests. Tests showed that the designed joint has enough margin of safety to endure joint failure. The developed sandwich panel to air spoiler is planned to be applied to a large scale commercial ship.

System Development for Analysis and Compensation of Column Shortening of Reinforced Concrete Tell Buildings (철근콘크리트 고층건물 기둥의 부등축소량 해석 및 보정을 위한 시스템 개발)

  • 김선영;김진근;김원중
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.291-298
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    • 2002
  • Recently, construction of reinforced concrete tall buildings is widely increased according to the improvement of material quality and design technology. Therefore, differential shortenings of columns due to elastic, creep, and shrinkage have been an important issue. But it has been neglected to predict the Inelastic behavior of RC structures even though those deformations make a serious problem on the partition wall, external cladding, duct, etc. In this paper, analysis system for prediction and compensation of the differential column shortenings considering time-dependent deformations and construction sequence is developed using the objected-oriented technique. Developed analysis system considers the construction sequence, especially time-dependent deformation in early days, and is composed of input module, database module, database store module, analysis module, and analysis result generation module. Graphic user interface(GUI) is supported for user's convenience. After performing the analysis, the output results like deflections and member forces according to the time can be observed in the generation module using the graphic diagram, table, and chart supported by the integrated environment.

Consumer Awareness Analysis of Residential Building Underground Structure Leakage Prevention Measurements (공동주택 지하공간 누수 예방 기술 정책 수립을 위한 소비자 인식 분석 연구)

  • Han, Yoon-Jung;Oh, Kyu-Hwan;Kim, Su-Ryon;Kim, Byoung-Il;Oh, Sang-Keun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.4
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    • pp.379-387
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    • 2016
  • In this study, a survey was conducted on the required measurement and waterproofing performance for residential building underground structure leakage prevention system. According to the results of the survey, it has been determined that leakage problem is considered to be quite severe, and many respondents have agreed. The legal guidelines and regulation systems do not reflect properly on the environmental requirements or conditions, resulting in continued leakage problem. In regards to this, a standardized waterproofing technique that can be used in underground areas of residential structures is required as an obligation and the development of high performance waterproofing method that allows for wet concrete surface adhesion and a guideline, design and maintenance method that allows the control of overall situational control of leakage is required.