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Effect of the YAG with fracture toughness and electric conductive of $\beta$-Sic-$TiB_2$ ($\beta$-Sic-$TiB_2$복합체의 파괴인성과 전기전도도젠 미치는 YAG의 영향)

  • Yoon, Se-Won;Ju, Jin-Young;Shin, Yong-Deok;Yeo, Dong-Hun;Park, Ki-Yub
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1545-1547
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    • 2000
  • The mechanical and electrical properties of the hot-pressed and annealed $\beta$-Sic-$TiB_2$ electroconductive ceramic composites were investigated as function of the liquid forming additives of $Al_{2}O_{3}+Y_{2}O_3$. Phase analysis of composites by XRD revealed $\alpha$-SiC(6H), $TiB_2$, and YAG($Al_{5}Y_{3}O_{12}$). The relative density and the mechanical properties of composites were increased with increasing $Al_{2}O_{3}+Y_{2}O_3$ contents because YAG of reaction between $Al_{2}O_3$ and $Y_{2}O_3$ was increased. The Flexural strength showed the highest value of 432.5MPa for composites added with l2wt% $Al_{2}O_{3}+Y_{2}O_3$ additives at room temperature. Owing to crack deflection, crack bridging, phase transition and YAG of fracture toughness mechanism. the fracture toughness showed 7.1MPa${\cdot}m^{1/2}$. For composites added with l2wt% $Al_{2}O_{3}+Y_{2}O_3$ additives at room temperature The electrical resistivity and the resistance temperature coefficient respectively showed the lowest of 6.0${\sim}10^{-4}{\Omega}{\cdot}$ cm and 3.1${\times}10^{-3}/^{\circ}C$ for composite added with l2wt% $Al_{2}O_{3}+Y_{2}O_3$ additives at room temperature. The electrical resistivity of the composites was all positive temperature coefficient resistance(PTCR) in the temperature range of 25$^{\circ}C$ to 700$^{\circ}C$.

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Analysis on the Characteristics and Performance of High Line as Industrial Heritage Regeneration (산업유산 재생으로서 하이라인의 특성 및 성과 분석)

  • Park, Wonseok
    • Journal of the Economic Geographical Society of Korea
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    • v.23 no.2
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    • pp.182-196
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    • 2020
  • The purpose of this study is to analyze the characteristics and performance of the High Line as an example of Industrial Heritage Regeneration, and to derive implications for setting the direction of urban regeneration. The results of this study are summarized as follows. First, five measurement elements were derived from governance, physical performance, economic performance, social performance and cultural performance as an analytical framework for analyzing the characteristics and performance of the high line as a case of industrial heritage regeneration, and a total of 15 indicators were selected for each element. Second, the analysis of the characteristics and performance of the High Line regeneration shows that the High Line regeneration project has resulted in the establishment of effective governance, the physical improvement considering historicity and placeness, and the economic revitalization of the underdeveloped mid-western region of Manhattan, while the drive-out of natives due to gentrification.

Markers of Collagen Change in Chronic Secondary Renal Disease Model in Rat (만성 속발성 신질환 모델동물에서 콜라젠 변화의 지표)

  • 남정석;김기영;이영순
    • Toxicological Research
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    • v.12 no.2
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    • pp.213-221
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    • 1996
  • In order to develop a suitable secondary renal disease model and diagnostic markers of renal disease in the rat, the change of PIIIP (aminoterminal procollagen III peptide) in serum and hydroxyproline levels in the renal tissue that reflect the synthesis of extracellular matrix (ECM) during development of experimental renal diseases were observed. Two types of experimental primary diseases, diabetes mellitus administrated by streptozotocin (STZ, 75 mg/kg, i.p.) and liver cirrhosis produced by bile duct ligation/scission (BDL/s) operation, were induced. The hydroxyproline level increased according to the high PIIIP and NCl(carboxyterminal procollagen IV peptide) in Western blot analysis as early as 1 week in the STZ treated-rat kidney. Increased renal ECM was observed at 15 weeks in STZ and BDL/s model under the microscopic examination. High PAS positive reaction was found in capillary basement membrane in STZ treated-rats and mesangium in BDL/s operated rats at this time, showing the histological characteristics of diabetic nephropathy and cirrhotic glomerulonephritis in human, respectively. Such secondary renal failure were supported by additional tests including urinalysis and renal function test. The serum PIIIP detected by ELISA was a useful parameter to estimate synthesis rate of renal ECM during development of renal disease without extrarenal fibrosis i.e. liver cirrhosis in rats. This study is proposed that STZ treatment or BDL/s operation may be a suitable experimental animal model for the induction and development of chronic secondary renal diseases. Morover, it was found that hydroxyproline level in renal tissues was a good parameter of the change of renal ECM at the early stage of the diseases without apparent histological changes. Especially, serum PIIIP could be a choice as a diagnostic or prognostic marker during the development of renal diseases in rats.

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A Study on Zen Fashion in the Point of View of Culture Transition (문화(文化) 전이(轉移)(culture transition)의 시각(視覺)에서 본 젠(禪) 패션 연구(硏究))

  • Park, Hye-Won
    • Journal of Fashion Business
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    • v.4 no.1
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    • pp.73-85
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    • 2000
  • The purpose of this study is for considering about Zen fashion in the point of view of culture transition. Through this research, the Far-East including Korea will be confirmed as a center of fashion culture in 21st century. The contents are the meaning of culture transition in Post Modern period, the meaning of Zen and changing of fashion trend as the background of Zen Fashion, and the characteristics of Zen fashion design. The results are as follows: Anti-western movement or dismantlement of culture has been represented the limitation of western centered culture. So the interesting about East means the changing to east from west in ideas. To make new creation in fashion field, the comprehension about the western fashion which has been preceeded and new trials using the our tradition will be needed. Zen is a kind of Buddhism and the essence of it is to find myself and express individual experiences. The change of one's sens of value, new age movement and concerning of environment and ecology make more comfortable, simple and healthy elements in clothing. The fusion style is under a vogue in life style and Zen is the core of this trend. The characteristics of Zen fashion are flat dismantlement which has been know as a Japanese style, oriental minimalism and nature beauty of ecology. This characteristics are found not only the shape, color but the will of the behind. The pursing temperance and naturalism are represented the fashion culture transition from the West to Far-East. Therefore multi points of fashion research is very important and the identify about Korean fashion is required in lately for new fashion paradigm.

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Liquid Crystalline Thermoset Films Based on Wholly Aromatic Copolymers (전방향족 공중합체의 열경화성 액정필름)

  • Moon, Hyun-Gon;Ahn, Yong-Ho;Chang, Jin-Hae
    • Polymer(Korea)
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    • v.34 no.4
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    • pp.369-375
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    • 2010
  • We used melt polymerization method to prepare a series of aromatic liquid crystals (LCs) based on aromatic ester and amide units with the reactive methyl-maleimide end group, and then the resulting thermally cross-linked LCs to produce LC thermoset films by means of solution casting and the followed heat treatment. The synthesized LCs and LCTs were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), X-ray diffractometry (XRD), and polarizing optical microscopy (POM) with a hot stage. All of the LCs prepared by melt polymerization method formed smectic mesophases. The thermal properties of the LC and LCT films were strongly affected by the mesogen units in the main chain structures. The thermal expansion coefficients of samples were in the range of 27.72~50.95 ppm/$^{\circ}C$.

Effect of Celecoxib on Lung Injury Improvement by Controlling Epithelial-Mesenchymal Transition(EMT) in Chronic Obstructive Pulmonary Disease(COPD) (만성폐쇄성폐질환에서 상피중간엽이행 조절을 통한 Celecoxib의 폐 손상 개선효과)

  • Lee, Sun-Kyung
    • Journal of Convergence for Information Technology
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    • v.11 no.11
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    • pp.248-255
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    • 2021
  • This study confirmed the effects of improving lung damage of celecoxib using an animal model of chronic obstructive pulmonary disease(COPD). It was induced in models LPS + CSE and performed in vitro and in vivo. MTT assay and real-time PCR were performed in MRC5 cells as in vitro, and mRNA expression, BALF, collagen content, and protein expression were confirmed as in vivo. Celecoxib reduced the number of inflammatory cells, cytokine and soluble protein accumulation in BALF, decreased body weight and lung weight in animal models, and improved lung collagen deposition. In addition, the reduction of EMT markers was confirmed through Western blotting and real-time PCR. Consequently, celecoxib is thought to improve lung damage of COPD induced to LPS+CSE by regulating EMT.

Genetic analysis of endangered species Crested Ibis (Nipponia nippon) microsatellite markers (Microsatellite Markers를 이용한 따오기의 유전적 특성 분석)

  • Kim, Da Hye;Kim, Yi Seul;Seo, Joo Hee;Kim, Sung Jin;Kong, Hong Sik
    • Korean Journal of Ornithology
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    • v.25 no.2
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    • pp.77-81
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    • 2018
  • The Korean Crested ibis Nipponia Nippon is an endangered species. A pair of Crested ibis was introduced from China in October 2008, and a successful program of artificial incubation of the species, and over 200 animals have been successfully bred through the restoration project up to 2017 at Upo ibis restoration center. We assessed genetic diversity and sex determination in the Korean Crested ibis. In total, 228 Crested ibis (115 females and 113 males) were identified. And genetic diversity measures, observed heterozygosity, expected heterozygosity, and polymorphic information content values were lower in 2017 than those in 2016. The inbreeding coefficient showed that the degree of ancestry increased in 2017. The decrease in polymorphism and increase in the degree of ancestry is thought to be due to inbreeding in such a small group. In this study provided important insight into protocols for genetic management of the breeding population of Korean Crested ibis in Korea and will help in extending the restoration program.

Analysis of Rent-Free Determinants : Evidence from Seoul Office Market (오피스 렌트프리 결정요인 분석 : 서울시를 중심으로)

  • Han, Gwang-Ho;Kwon, Hee-Jae;Ro, Seung-Han
    • Journal of Cadastre & Land InformatiX
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    • v.49 no.1
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    • pp.5-15
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    • 2019
  • This study is to review methodological limitations of previous studies, propose Tobit Model as an analysis model. We model used annual rent-free as dependent variable and considering to contract characteristics and building characteristics as independent variable. We model was consisted to the three model as follow: Basic model, Time control model, Quadratic model. As a result of the analysis, existing variables revealed through previous studies such as contract period, contract area, total floor area, and building age were all statistically significant. These results were robust when considering time effects. Also, floor area and annual rent-free was quadratic relationship by inverse U shape. This result provide to methodological contribution for related research. Also, provide to more accurate information for participants in seoul office market.

Selective Laser Melting of Metal Matrix Composites: A Review of Materials and Process Design (레이저로 적층 제조한 금속 기지재 복합재료의 설계 및 제조 연구동향)

  • Kim, Min-Kyeom;Kim, Taehwan;Kim, Ju-won;Kim, Dongwon;Fang, Yongjian;No, Jonghwan;Suhr, Jonghwan
    • Composites Research
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    • v.34 no.4
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    • pp.212-225
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    • 2021
  • Metal matrix composites (MMCs) were widely used in various industries, due to the excellent properties: high strength, stiffness, wear resistance, hardness, thermal conductivity, electrical conductivity, etc. With additive manufacturing (AM) technology rapidly developed, AM MMCs have been actively investigated thanks to the cost- and time-saving manufacturing. However, several issues still need to be addressed before fabricating AM MMCs. Here, several types of MMCs were introduced and MMCs' design methods to tackle the issues were suggested in a powder bed fusion (PBF) technique. The paper could come up with a guideline for the material and process design of MMCs in the PBF technique.

Development of Cleaved Amplified Polymorphic Sequence Markers of Lentinula edodes Cultivars Sanbaekhyang and Sulbaekhyang (표고 품종 산백향과 설백향 구분을 위한 CAPS 마커 개발)

  • Moon, Suyun;Hong, Chang Pyo;Ryu, Hojin;Lee, Hwa-Yong
    • The Korean Journal of Mycology
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    • v.49 no.1
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    • pp.33-44
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    • 2021
  • Lentinula edodes (Berk.) Pegler, the most produced mushroom in the world, is an edible mushroom with very high nutritional and pharmacological value. Currently, interest in the protection of genetic resources is increasing worldwide, and securing the distinction between new cultivars is very important. Therefore, the development of efficient molecular markers that can discriminate between L. edodes cultivars is required. In this study, we developed cleaved amplified polymorphic sequence (CAPS) markers for the identification of L. edodes cultivars (Sanbaekhyang and Sulbaekhyang). These markers were developed from whole genome sequencing data from L. edodes monokaryon strain B17 and resequencing data from 40 cultivars. A nucleotide deletion existed in scaffold 19 POS 214449 in Sanbaekhyang (GT→G), and a single nucleotide polymorphism changed in scaffold 7 POS 215801 in Sulbaekhyang (G→A). The restriction enzymes Hha I and HpyCH4IV distinguished Sanbaekhyang and Sulbaekhyang, respectively, from other cultivars. Thus, we developed two CAPS markers for the identification of the L. edodes cultivars Sanbaekhyang and Sulbaekhyang.