• Title/Summary/Keyword: 유리조성

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Preparation and Performance Improvement of Polylactic acid based composites by stereocomplex (스테레오 컴플렉스를 이용한 폴리유산 복합재 제조 및 성능 개선)

  • Hong, Chae-Hwan;Kim, Yeon-Hee;Park, Jun-Seo;Nam, Byeong-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.3
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    • pp.1671-1676
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    • 2015
  • A unique crystallization behavior of poly(L-lactide)(PLLA)/poly(D-lactide)(PDLA) stereocomplex(SC) was observed when a PLLA/PDLA blend was subjected to the specific melting conditions. Therefore, we tried to blend PLLA and PDLA at overall composition to form PLA stereocomplexes. Moreover, impact modifier and reinforcement materials such as talc and glass fiber added to enhance the mechanical and thermal properties such as impact strength and heat distortion temperature(HDT). As a result, we got one representative result, one composite recipe with HDT $115^{\circ}C$. For more economic technology, we tried to blend PLLA and Polypropylene at overall composition and we got another representative result which could be applied to current PP/talc composites and ABS materials. The core technology of this might be the well dispersion of glass fibers into the matrix resin such as PP, PLLA and impact strength modifier.

Determination of optical properties of Pr3+-doped selenide glasses of Ge-Sb-Se system using spectroscopic ellipsometry (분광타원법을 이용한 Pr 첨가 Ge-Sb-Se 계열 셀레나이드 유리의 굴절률 결정)

  • 신상균;김상준;김상열;최용규;박봉제;서홍석
    • Korean Journal of Optics and Photonics
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    • v.14 no.6
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    • pp.594-599
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    • 2003
  • By using the spectroscopic ellipsometry, we have measured and analyzed the optical characteristics of P $r^3$$^{+}$-doped selenide glasses of Ge-Sb-Se system, a strong candidate material for U band fiber amplifiers. The ellipsometric spectra measured in the transparent wavelengths range of the material were all fitted to a model consisting of ambient/roughness/thin fil $m_strate structures to obtain simultaneously the optical properties such as refractive index, in terms of Sellmeier parameters and film structure of P $r^3$$^{+}$-doped selenide glasses. Repeated measurements on different positions in both polished faces rendered to verify positional dependence of measured spectre-ellipsometric data. Hence, the model made possible the analysis of the optical characteristics of the glasses. Even though surface roughness was mainly responsible for the position dependencies, the averaged refractive indexes were as precise as to reflect the minute compositional change tantamount to 1 mol%. The measured refractive indexes are useful for design of core and clad compositions of single-mode selenide optical fibers.

Availability of the Skeletonized Gastroepiploic Artery as a Free Graft for Coronary Artery Bypass Grafting (관상동맥 우회로 조성술에 있어 유리 이식편으로 사용된 골격화 우위대망 동맥의 효용성)

  • Ryu Sang-Wan;Ahn Byong-Hee;Hong Seong-Beom;Song Sang-Yun;Jung In-Suk;Beom Min-Sun;Park Jung-Min;Lee Kyo-Sun;Ryu Sang-Woo;Yoon Ju-Sik;Kim Sang-Hyung
    • Journal of Chest Surgery
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    • v.38 no.9 s.254
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    • pp.601-608
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    • 2005
  • Background: To maximize the histological advantage and minimize the physiological disadvantage, we have been using the skeletonized gastroepiploic artey (GEA) as a free graft for total arterial revascularization. The aims of the current study was to assess the efficacy of the skeletonized GEA as a composite or extended graft for total arterial revascularization. Material and Method: Between January 2000 and Feburary 2005, 133 patients (43 female, mean age=61.8 yrs) undergoing coronary artery bypass grafting (CABG) with a skeletonized GEA as free graft (22 extended, 107 composite and 4 others) were enrolled in this study. Coronary angiograms were performed in the immediate (median 44 days, n=86), early (median 366 days, n=56) and midterm (median 984 days, n=29) postoperative periods. Result: There were 3 ($2.2\%$) early and 4 ($3.3\%$) late cardiac-related deaths. The mean number of distal anastomoses per patient was 3.34 for total graft and 1.92 for GEA graft. The immediate, early, and midterm GEA patency were 157/159 ($98.7\%$), 106/142 ($94.6\%$), and 53/56 ($94.6\%$), respectively. During follow-up, four patients required percutaneous intracoronary intervention because of GEA and target coronary artery stenosis or competitive flow. Conclusion: These data demonstrate satisfactory clinical and angiographic results in the skeletonized GEA as free graft for total arterial revascularizatioh. Although we need a careful longer follow-up, the skeletonized GEA as a free graft will be a valuable option 'to be' for CABG.

Scientific Conservation and Analysis of Octagonal Green Glass Bottle Excavated from Tomb Hwayu princess (화유옹주묘 출토 녹유리장경각병-보존과 분석)

  • Gang, Hyeong-Tae;Yang, Pil-Seung;Heo, U-Yeong;Jo, Nam-Cheol
    • KOMUNHWA
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    • no.70
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    • pp.5-15
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    • 2007
  • Octagonal green glass bottle with long neck(녹유리장경각병) was found in the tomb of the princess Hwayu who was King Youngjo's daughter by a concubine while the tomb was exhumed and buried in another place around Bucheon City, Gyeonggi-do. This octagonal glass bottle is dark green. It was made in AD 1736-A1795 because it was cngraved an inscription of "건륭년제" the bottom. This glass bottle was taken an X-ray radiography and tested adhesives and restoration materials for the conservation. Loctite 401 was suitable as considering the translucency of the glass bottle, good adhesive property and reversibility of the adhesive so it was chosen. A minute piece of the glass was analyzed the composition and lead isotope ratio. Major chemical composition of the glass bottle consisted of SiO2, K2O, and PbO system and the ratio was 68: 18.5:5.7. Green color of glass bottle was due to Fe2O3 and CuO. When the glass bottle was made, quartz as raw material of silica and K2O as natural saltpeter(KNO3) were utilized. As a result of lead isotope ratio analysis, it was suggested that the galena as raw material of lead for glass making came from the southern part of China. These results are expected to become useful data in background of glass culture and circulation study of old glass.

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국내 저탄소 그린에너지 특집 3탄 - 바다의 힘! 바람에너지를 잡아라

  • Son, Yeong-Seon
    • Electric Engineers Magazine
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    • s.335
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    • pp.11-13
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    • 2010
  • 우리나라는 좁은 국토 면적에 비하여 삼면이 바다로 둘러싸인 지형적인 장점을 가지고 있어 해상풍력발전단지를 조성하는데 유리한 조건을 가지고 있다. 또한 해상풍력은 장애물이 적기 때문에 바람의 난류(불규칙적인 흐름)와 풍속변화가 적어 육상풍력보다 해상풍력의 발전효율이 1.4배 높으며, 일반적으로 1.5~2배 정도 발전량이 높은 것으로 알려져 해상풍력 개발에 박차를 가하고 있다.

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`93한국포장산업의 동향

  • 한국포장협회
    • The monthly packaging world
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    • s.8
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    • pp.42-46
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    • 1993
  • 올해 포장산업을 결산하기는 다소 이르지만 몇 가지 흐름을 짚어 보았다. 가장 두드러진 경향은 역시 환경대응의 노력인 것으로 보인다. 그밖에 고기능의 고부가가치 제품 생산, 물류혁신, 산업디자인 발전의 기반 조성, 여러 포장산업관련 단체의 출현 등도 눈에 띄인다. 기계기기, 종이 및 골판지(상자), 제관 및 유리산업과 관련해서는 다음에 언급할 기회가 있을 것으로 생각한다.

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