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The Characteristic Changes of Electromagnetic Wave Absorption in Fe-based Nanocrystalline P/M Sheets Mixed with Ball-Milled Carbon Nanotubes (Fe계 나노결정립 분말 시트에 첨가된 CNT의 볼밀 공정에 따른 전자파 흡수 특성 변화)

  • Kim, Sun-I;Kim, Mi-Rae;Sohn, Keun-Yong;Park, Won-Wook
    • Journal of Powder Materials
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    • v.16 no.6
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    • pp.424-430
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    • 2009
  • Electromagnetic wave energies are consumed in the form of thermal energy, which is mainly caused by magnetic loss, dielectric loss and conductive loss. In this study, CNT was added to the nanocrystalline soft magnetic materials inducing a high magnetic loss, in order to improve the dielectric loss of the EM wave absorption sheet. Generally, the aspect ratio and the dispersion state of CNT can be changed by the pre-ball milling process, which affects the absorbing properties. After the various ball-milling processes, 1wt% of CNTs were mixed with the nanocrystalline $Fe_{73}Si_{16}B_7Nb_{3}Cu_1$ base powder, and then further processed to make EM absorption sheets. As a result, the addition of CNT to Fe-based nanocrystalline materials improved the absorption properties. However, the increase of ball-milling time for more than 1h was not desirable for the powder mixture, because the ballmilling caused the shortening of CNT length and the agglomeration of the CNT flakes.

The Hierarchy of Images according to Construction Factors of the Flared Skirts

  • Lee, Jung-Soon;Han, Gyung-Hee
    • Journal of Fashion Business
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    • v.13 no.6
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    • pp.137-146
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    • 2009
  • This study analyzed hierarchy of image for visual evaluation of flare skirt. This study analyzed expression words about flare skirt with frequency data of image expression words with different length and volume of flare. Stimuli for the study were set to be 4 different volume of flare ($90^{\circ}$, $180^{\circ}$, $270^{\circ}$, $360^{\circ}$) and 3 different length of skirt(48cm, 58cm, 68cm). Stimuli were made by using I-Designer which is Virtual Sewing System. From simulation of flare skirt, the subjects were asked to write down suggested adjective freely and selected 210 adjectives. With this, we chose total 38 adjectives considering frequencies in the pre-study. And we analyzed the combination process of expression words according to construction factor of flare skirt and hierarchy of image from dendrogram which was resulted by hierarchical cluster analysis. 'Feminine' got high score in all 12 flare skirt. When the skirt was short, it was vivid, and as the skirt got longer, ordinary and pure image showed. Also, as the volume of flare got larger, the average of visual effect was higher than visual image. Visual hierarchy construction according to construction factors of flare skirt could be divided into visual image and visual effect, and visual image was shown to be form 'A type - large volume of flare and short skirt length', 'H type-small volume of flare and short skirt length' and 'X type - large volume of flare and long skirt length'.

Fabrication of SiCN microstructures for super-high temperature MEMS using photopolymerization and its characteristics (광중합에 의한 초고온 MEMS용 SiCN 미세구조물 제작과 그 특성)

  • Chung, Gwiy-Sang
    • Journal of Sensor Science and Technology
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    • v.15 no.2
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    • pp.148-152
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    • 2006
  • This paper describes the fabrication of SiCN microstructures for super-high temperature MEMS using photopolymerization of pre-ceramic polymer. In this work, polysilazane liquide as a precursor was deposited on Si wafers by spin coating, microstructured and solidificated by UV lithography, and removed from the substrate. The resulting solid polymer microstructures were cross-linked under HIP process and pyrolyzed to form a ceramic of withstanding over $1400^{\circ}C$. Finally, the fabricated SiCN microstructures were annealed at $1400^{\circ}C$ in a nitrogen atmosphere. Mechanical characteristics of the SiCN microstructure with different fabrication process conditions were evaluated. The elastic modules, hardness and tensile strength of the SiC microstructure implemented under optimum process condtions are 94.5 GPa, 10.5 GPa and 11.7 N/min, respectively. Consequently, the SiCN microstructure proposed in this work is very suitable for super-high temperature MEMS application due to very simple fabrication process and the potential possiblity of sophisticated mulitlayer or 3D microstructures as well as its good mechanical properties.

Comparison of Complementary Forest of Village between Korea and China - Focuced on Jinan in Korea and Qingzhou in China - (한국과 중국의 마을비보숲 비교 - 한국(韓國) 진안(鎭安)과 중국(中國) 청주(靑州)를 사례로-)

  • Park, Jae-Chul;Gwan, Dan Dan;Jung, Kyoung-Sook
    • Journal of Korean Society of Rural Planning
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    • v.18 no.2
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    • pp.27-37
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    • 2012
  • The purpose of this study is on comparing complementary forest of village between Korea and China. For this, Jinan of Korea and Qingzhou of China were selected through the pre-survey about the representative region of both country. The main research method was literature study, field study and interview with local residents. The comparative analysis between two regions was performed by frequency analysis of surveyed data. Which shows complementary forest of village in two regions has so much in common and also has many differences which is related with the local practical life. As a result, it was identified that the area and remained number, concentration degree of Jinan were greater than those of Cheongju. But it was identified that the linear form and location were similar in both regions. Through these identification, it is helpful to establish policy direction of both countries about the complementary forest.

Irreversible Hemorrhagic Complication of Recurrent Posterior Reversible Encephalopathy Syndrome in a Patient with Systemic Lupus Erythematosus (전신성 홍반성 낭창 환자에서 재발한 가역적 후두부 뇌병증 증후군의 비가역적 출혈성 합병증)

  • Kim, Ho Kyun;Lee, Hui Joong;Shin, Kyung Min
    • Investigative Magnetic Resonance Imaging
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    • v.17 no.2
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    • pp.144-148
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    • 2013
  • Although most cases of posterior reversible encephalopathy syndrome (PRES) are reversible, irreversible lesions as a form of hemorrhage or infarction have been described. PRES as a complication of systemic lupus erythematosus (PRES-SLE) is associated with hypertension or use of immunosuppressive agents. We present a case of recurrent atypical PRES-SLE, which showed restricted diffusion in the first manifestation of SLE, resulted in parenchymal hemorrhagic transformations in the recurrent episode.

Enhancing Writing Skills Through Portfolios

  • Rafik-Galea, Shameem
    • English Language & Literature Teaching
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    • v.9 no.2
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    • pp.17-33
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    • 2003
  • College going students who are non-native speakers of English enrolled in English language programmes are not acquiring the needed academic writing skills. Many of these students do not have positive attitudes towards writing, thus forcing language instructors to look for ways of motivating students to write in order to improve writing skills. This action research project investigates the use of portfolio writing to improve writing ability among pre-university students. Research on the use of portfolio writing suggests that it is a useful way for developing interest in writing and for developing effective writing skills over a period of time. Portfolios support the best thinking in composition pedagogy in that it encourages process writing. Although the portfolio is considered a writing product, as a whole it is evidence of the students writing process. An important feature in using portfolios is that students are able to focus on their writing without constantly worrying about grades. Instructors have noticed that students make greater improvement in their writing when their focus is shifted from punitive feedback through letter grades to constructive feedback in the form of suggestions for further revision. This paper describes the use of writing portfolios as an effective means of teaching writing. The findings revealed that writing portfolios helped develop confidence in writing and decreased anxiety towards writing. (217 words)

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Improved Efficiency by Insertion of TiO2 Interfacial Layer in the Bilayer Solar Cells

  • Xie, Lin;Yoon, Soyeon;Kim, Kyungkon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.432.1-432.1
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    • 2016
  • We demonstrated that the power conversion efficiency (PCE) of bilayer solar cell was significantly enhanced by inserting interfacial layer between the organic bilayer film and the Al electrode. Moreover, the water contact angle shows that the bilayer solar cells suffer from the undesirable surface component which limits the charge transport to the Al electrode. The AFM measurement has revealed that the pre- and post-thermal annealing treatments results in different morphologies of the interfacial layer which is critical for the higher PCE of the bilayer solar cells. Furthermore we have investigated the electrical properties of the bilayer solar cells and obtained insights into the detailed device mechanisms. The transient photovoltage measurements suggests that the significantly enhanced Voc is caused by reducing the recombination at the interface between the organic films and the Al electrode. By inserting the TiO2 layer between the bilayer film and Al electrode, the open circuit voltage (Voc) was increased from 0.37 to 0.66V. Consequently, the power conversion efficiency (PCE) of bilayer solar cells was significantly enhanced from 1.23% to 3.71%. As the results, the TiO2 interfacial layer can be used to form an ohmic contact layer, serveing as a blocking layer to prevent the penetration of the Al, and to reduce the recombination at the interface.

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Development of Social Capital Scale in Participant Sports (스포츠 참여자의 사회자본 철도개발 적용)

  • Kim, Myoung-Joon
    • Proceedings of the Korea Contents Association Conference
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    • 2006.11a
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    • pp.124-128
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    • 2006
  • The purpose of this study was to develop a scale of social capital in participant sports. To achieve the purpose of this study Socal Capital Scale by Fukuyama(1996), Shane(2005), Kim(2003), Park & Kim(2000), Jung & Shim(2004) was translated and modified to use in participant sports. Throughout the research procedures including back translation, expert meeting, pre-test, sampling, data analysis. Result of this study are as follows First, SCSPS(social capital scale in participant sports) was consisted with four sub-domains such as social network, norms, trust, information share, and position improvement. Second, based on outputs form SEM, it was indicated that model used to develop SCSPS had relatively good fit with significant scores of model indices. Finally, reliability and validity of the scale also showed relatively high scores.

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Electrical and Mechanical Properties of Semiconducting Shield for Power Cable by Carbon Nanotube Content (탄소나노튜브(CNT) 함량에 따른 전력케이블용 반도전 재료(층)의 전기적/기계적 특성 연구)

  • Yang Jong-Seok;Lee Kyoung-Yang;Shin Dong-Hoon;Park Dae-Hee
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.8
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    • pp.381-386
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    • 2006
  • In this study, we have investigated electrical and mechanical properties of semiconducting materials for power cable caused by CNT. Specimens were made of sheet form with the four of specimens for measurement. Volume resistivity of specimens was measured by volume resistivity meter after 10 minutes in the pre-heated oven of both $23{\pm}\;1\;[^{\circ}C]\;and\;90{\pm}\;1\;[^{\circ}C]$. And stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400[Kgf/Cm2] and 600[%]. From this experimental results, the volume resistivity had different properties because of PTC/NTC tendency at between $23[^{\circ}C]\;and\;90[^{\circ}C]$. Also volume resistivity was low by increasing the content of CNT. It means that a small amount of CNT has a excellent electrical properties. And stress was increased, while strain was decreased by increasing the content of CNT. Thus, we could know that a small amount of CNT has a excellent electrical and mechanical oroperties.

Effect of Stretching Exercise on Depression, Pain, and Fatigue in Patients with Systemic Lupus Erythematosus (신전운동이 루푸스 환자의 우울, 통증 및 피로에 미치는 영향)

  • An, Min-Jeong;Park, In-Hyae
    • Journal of muscle and joint health
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    • v.13 no.1
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    • pp.43-52
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    • 2006
  • Objective: The purpose of this study was to determine the effect of stretching exercise on depression, pain, and fatigue in patients with systemic lupus erythematosus(SLE). Methods: The study was designed as a non-equivalent control group pre-posttest quasi-experimental design. The patients with SLE who signed the consent form were conveniently assigned into two groups(11 experimental subjects and 10 control subjects). The subjects in the experimental group were participated in 6 weeks stretching exercise program for one and a half hours per session twice a week. The data were analyzed by using a SAS-pc+ 8.01 program. Results: 'The experimental group would have less depression scores than the control group' was supported (Z=2.2, p=.025). 'The experimental group would have less pain scores than the control group' was supported (Z=3.4, p=.001). 'The experimental group would have less fatigue scores than the control group' was supported (Z=-2.0, p=.041). With this study, we identified the stretching exercise program was effective on depression, pain, and fatigue of SLE patients. Conclusions: From above results, 6 weeks stretching exercise program could be an effective nursing intervention to reduce depression, pain, and fatigue in patients with SLE.

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