• Title/Summary/Keyword: rGO

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Effect of Interfacial Bonding on Piezoresistivity in Carbon Nanotube and Reduced Graphene Oxide Polymer Nanocomposites (탄소나노튜브 및 환원된 산화그래핀과 고분자간 계면결합력이 나노복합재의 압전 거동에 미치는 영향)

  • Hwang, Sang-Ha;Kim, Hyeon-Ju;Sung, Dae-Han;Jung, Yeong-Tae;Kang, Ku-Hyek;Park, Young-Bin
    • Journal of Adhesion and Interface
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    • v.13 no.3
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    • pp.137-144
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    • 2012
  • Chemical functionalization of carbon nanomaterials (CNMs) is generally carried out for increasing interfacial adhesion between filler and polymer matrix for CNM-polymer nanocomposites. The chemically functionalized CNTs can produce strong interfacial bonds with many polymers, allowing CNT based nanocomposites to possess high mechanical and functional properties. Hence, increased surface adhesion can be measured indirectly by observing increased mechanical properties. However, there is a more direct way to observe interfacial bonds between polymer and CNM by measuring piezoresistivity behavior so that we can imagine the behavior of CNM particles in polymer matrix under deflection. Fuctionalization of MWCNT and rGO was carried out by oxidization reaction of MWCNT and rGO with $H_2SO_4/HNO_3$ solution. Electrical resistivities of MWCNT-PMMA and rGO-PMMA composites were decreased after functionalization because of the destructive fuctionalization process. Meanwhile, piezoresistivities of functionalized CNM-PMMA composites showed more sensitive behavior under the same deflection as compared to pristine CNM-PMMA composites. Therefore, mobility of CNM in polymer matrix was found to be improved with chemical functionalization.

An Analytic Network Process(ANP) Approach to Forecasting of Technology Development Success : The Case of MRAM Technology (네트워크분석과정(ANP)을 이용한 기술개발 성공 예측 : MRAM 기술을 중심으로)

  • Jeon, Jeong-Hwan;Cho, Hyun-Myung;Lee, Hak-Yeon
    • IE interfaces
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    • v.25 no.3
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    • pp.309-318
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    • 2012
  • Forecasting probability or likelihood of technology development success has been a crucial factor for critical decisions in technology management such as R&D project selection and go or no-go decision of new product development (NPD) projects. This paper proposes an analytic network process (ANP) approach to forecasting of technology development success. Reviewing literature on factors affecting technology development success has constructed the ANP model composed of four criteria clusters : R&D characteristics, R&D competency, technological characteristics, and technological environment. An alternative cluster comprised of two elements, success and failure is also included in the model. The working of the proposed approach is provided with the help of a case study example of MRAM (magnetic random access memory) technology.

VD GoGo-전자부품연구원(KETI)

  • Korea Venture Business Association
    • Venture DIGEST
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    • s.115
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    • pp.12-15
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    • 2008
  • 중소벤처기업은 기술에 의지하여 시장에서 경쟁한다. 하지만, 혁신적인 기술아이템을 보유했다 하더라도 혼자만의 힘으로 사업 성공을 이루어 내기 위해서는 난관과 장애가 많은 것이 현실. 이와 같은 현실을 파악하고 전자부품연구원(KETI, www.keti.re.kr, 원장 서영주)에서는 90년대 후반부터 단순한 R&D 수준을 넘어 비즈니스마인드를 접목한 'R&BD'를 통해 중소벤처기업을 지원하기 위한 다양한 사업을 해오고 있다. 석박사 이상의 400여명의 연구 인력과 고급 R&D 인프라를 바탕으로 기술개발 외에 기술평가와 투자유치 지원, 생산 아웃소싱, 국내외 마케팅, 대기업과의 공동협력 등 중소벤처기업의 사업 전 과정을 하나의 시스템으로 구성하여 지원하고 있다. 기술혁신과 활성화로 기술경쟁력 제고에 기여하는 전자부품연구원. 중소벤처기업의 기술개발에서부터 기술 사업화 등 다양한 지원내용을 소개한다.

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Comparisons of physical Fitness, Self Efficacy, Instrumental Activities of Daily Living, and Quality of Life between Institutionalized and Noninstitutionalized Elderly (가정노인과 양로원노인의 체력, 자기효능, 일상생활활동능력 및 삶의 질에 관한 연구)

  • 노유자;김춘길
    • Journal of Korean Academy of Nursing
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    • v.25 no.2
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    • pp.259-278
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    • 1995
  • This study was done to investigate levels of physical fitness, self efficacy(SE), instrumental activities of daily living(IADL), and quality of life (QL), and their relationships among the elderly Data were collected from 47 noninstitutionalized elderly dwell-ing in their own homes and 43 institutionalized elderly living in homes for older people. The ages of the subjects were 65 years and over. The data were col lected from January 20th to February 20th, 1995. Physical fitness was measured with T.K. K dyna mometer, grip dynamometer, stop watch, and Purdue pegboard. Structured questionnaires developed by Kim by Lawton & Brody, and by Ro were adopted to measure SE, IADL, and QL, respectively. The data were analyzed using t-test, ANOVA, and Pearson correlation coefficients. The results were as follows : 1. The noninstitutionalized elderly had higher scores in such measures of physical fitness as body weight, skinfold thickness, flexibility and coordination as compared to the institutionalized elderly. 2. On the following measures of physical fitness, men showed higher levels than women ; in height when standing, height when sitting, body weight, and muscle strength. Women had more trunk flexibility than men. 3. Muscle strength was positively correlated with height when standing, height when sitting, and body weight. The following measures of physical fitness, muscle strength, flexibility and coordi nation, were negatively correlated with "up and go”. 4. The noninstitutionalized elderly had higher scores in SE(t=2.28, p<0.05), IADL(t=2.24, p<0.05), and QL(t=2.41, p<0.05) as compared to the institutionalized elderly. 5. SE was positively correlated with both IADL(r=0.41, p<0.001) and QL(r=0.54, p<0.001), and the latter two variables were a positively correlated (r=0.30, p<0.001). 6. SE was positively correlated with the physical fitness measures of height when standing, body weight, strength of leg muscles, strength of back muscles, grip strength, and level of touching the floor, but negatively correlated with "up and go”. 7. Positive correlations were revealed between IADL and the physical fitness measures of height, strength of leg muscles, level of trunk muscle extension, level of touching the floor, and coordination. The IADL was negatively correlated with “up and go”. 8. QL was positively correlated with body weight (r=0.28, p<0.01) and skinfold thickness (r=0.26, p<0.05). 9. Age was negatively correlated with the physical fitness measures of height when standing, height when sitting, “up and go”, strength of leg muscles, strength of back muscles, grip strength, level of trunk muscle extension, and coordination. 10. Age was also negatively correlated with SE (r=-0.24, p<0.05) and IADL(r=-0.22, p<0.05). The above results suggest that caring elderly in their own homes were more effective and that nursing interventions to enhance physical fitness, SE, IADL, and QL especially for the institutionalized elderly are stressed.

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A Study on Shock-induced Detonation in Gap Test (충격 전달에 의한 Gap Test의 폭굉 반응 해석)

  • Kim, Bohoon;Kang, Wonkyu;Jang, Seung-gyo;Park, Jungsu;Yoh, Jai-ick
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.2
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    • pp.75-85
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    • 2016
  • A pyrotechnic system consisting of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and acceptor charges. Despite of its common use, numerical study of such pyrotechnic train configuration is seldom reported because proper modeling of the full process requires precise capturing of the shock wave attenuation in the gap prior to triggering a full detonation of high explosive and accurate description of the high strain rate dynamics of the explosively loaded inert confinements. We apply a Eulerian level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized RDX as acceptor charge. The complex shock interaction, critical gap thickness, acoustic impedance, and go/no-go characteristics of the gap test are quantitatively investigated.

Survey on 'Go Bag' Items in Internet Shopping Malls

  • PARK, Sang-Kyu;UHM, Tai-Hwan
    • Journal of Distribution Science
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    • v.17 no.7
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    • pp.39-44
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    • 2019
  • Purpose - This research was to help distribution of Go Bags (Survival Bag or Disaster Supplies Kit), which are useful for disaster preparedness, by surveying precomposed Go Bag items in internet shopping malls. Research design, data, and methodology - We checked 15 items including food, water, first aid kit, radio, flashlight or candles, battery, lighter or matches, whistle, blanket, towel, toilet paper, personal sanitations, raincoat, can opener, disaster manual in Go Bags based on the recommendations by the Ministry of the Interior and Safety. The number of items and price, domestic product, accreditation were compared using a Chi-square test. The Pearson's R was also used to summarize the strength of the linear relationship between the number of items and price, sub-items. Results - Mean of the sub-items was 21, and mean of the items was 8. There was a statistically significant difference between the number of items size and the price level (p=.014). There was also a statistically significant difference between the number of items and sub-items (p<.001), and correlation coefficient was a positive linear relationship of .467. Conclusions - Only eight were sold in the internet shopping malls as a precomposed Go Bag items. Even the approved Go Bags had no difference in the number of items. Higher prices had a relatively greater number of items, and it had a positive correlation between the size of sub-items and items.

Therapeutic Efficacy of Low Frequency Transcranial Magnetic Stimulation in Conjunction with Mirror Therapy for Sub-acute Stroke Patients

  • Cha, Hyun Gyu;Kim, Myoung-Kwon
    • Journal of Magnetics
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    • v.20 no.1
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    • pp.52-56
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    • 2015
  • The purpose of the current study was to investigate the effect of repetitive transcranial magnetic stimulation (rTMS) in conjunction with mirror therapy on the balance function of patients with sub-acute stroke hemiparesis. This study was conducted with 36 subjects who were diagnosed with a hemiparesis due to stroke. Participants in the experimental (19 members) and control groups (17 members) received rTMS and sham rTMS during 10 minute sessions each, which were carried out five days per week for four weeks. This was followed by the mirror therapy over 30 minute sessions, which were carried out five days per week for four weeks. Motor recovery was assessed by balance index, dynamic limits of stability, Berg balance scale, and time up go test. The change values of the balance index ($-2.06{\pm}1.99$ versus $-0.41{\pm}1.11$), dynamic limits of stability ($3.68{\pm}2.71$ versus $1.17{\pm}2.38$), and time up go test ($-7.05{\pm}5.64$ score versus $-3.35{\pm}5.30$ score) were significantly higher in the experimental group than in the control group (p < 0.05). At post-test, balance index ($4.08{\pm}1.14$ versus $5.09{\pm}1.04$), dynamic limits of stability ($13.75{\pm}0.60$ versus $11.73{\pm}3.53$), and time up go test ($23.89{\pm}4.51$ versus $28.82{\pm}3.07$) were significantly higher in the experimental group than in the control group (p < 0.05). In the experimental group, significant differences were found in the pre- and post-test scores for the balance index, dynamic limits of stability, Berg balance scale, and time up go test (p < 0.01). In the control group, a significant difference was observed between the pre- and post-test only for the Berg balance scale and time up go test (p < 0.05). These findings demonstrate that the application of 1Hz rTMS in conjunction with mirror therapy can be helpful in improving the balance function of patients with sub-acute stroke hemiparesis, and this may be used as a practical adjunct to routine rehabilitation therapy.