• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.642-649
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• 2021

Energy saving standard for buildings are strengthened, the application of exterior insulation finishing system and thickness of insulation materials are increasing. Most buildings with exterior insulation finishing system is applied organic insulating material. Organic insulating material have workability, economic feasibility, reduction in construction cost, and excellent thermal insulation performance. However, Organic insulating material is very vulnerable to heat, so when a fire occurs, rapid fire spread and toxic gas are generated, causing many casualties. Inorganic insulating material can be non-combustible performance, but it is heavy and has low thermal insulation performance. Mineral wool has higher thermal insulation performance than other types of inorganic insulating material, but mineral wool is disadvantageous to workability and vulnerable to moisture. Glass bubble are highly resistant to water and chemically stable substances. In addition, the density of the glass bubble is very low and the particles are spherical, fluidity is improved by the ball bearing effect. Glass bubbles can be used with cement-based ino rganic insulating material to impro ve the weight and thermal insulatio n perfo rmance o f cement-based inorganic insulation. This study produced a inorganic insulating materials were manufactured using cement-based materials and glass bubble. In order to evaluate the insulation performance and flame retardant performance of cement-based super light-weight inorganic insulating materials using with glass bubble, insulation performance or flame retardant and non-combustible performance were evaluated after manufacturing insulating materials using micro cement and two types of glass bubbles. From the test result, Increasing the mixing ratio of glass bubbles improved the insulation performance of cement-based super light-weight inorganic insulating materials, and when the mixing ratio of glass bubbles was 10%, it sho wed sufficient flame retardant and no n-co mbustible perfo rmance.

• Journal of Korean Medical classics
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• v.19 no.4
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• pp.147-168
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• 2006

통과대이연화장개빈관우중풍관점적비교연구, 이급기대중풍적분류(以及基對中風的分類), 증상(證狀), 치료(治療), 예후적관점진행분석득출여하결론(豫後的觀點進行分析得出如下結論): 이연파중풍적원인분류위진중풍(李挻把中風的原因分類爲眞中風), 겸중풍(兼中風), 류중풍(類中風), 사중풍(似中風), 종이조취료구분외풍여내풍계기(從而造就了區分外風與內風契機). 대어중풍적원인(對於中風的原因), 장개빈주장배제외풍근한어내풍적관점(張介賓主張排除外風僅限於內風的觀點). 재차기초상(在此基礎上), 설기여조헌가주장진수고갈급진화허시기원인소재(薛己與趙獻可主張眞水枯褐及眞火虛是基原因所在), 대차관점(對此觀點), 장수신적"중풍각전"중, 기유찬동적(旣有贊同的), 역유지비판의견적내용(亦有持批判意見的內容). 대어중풍적증상(對於中風的證狀), 이연근거병사소재분위중장, 중부(中부), 중혈맥(中血脈), 중경등(中經等). 우기대중경증적분류(尤基對中經證的分類), 재기타의서중시무법견도적분류적표준(在基他醫書中是無法見到的分類的標準). 저가이인위(這可以認爲), 타이 "금궤요략" 위의거(爲依據), 시부합내풍적증상분류(是符合內風的症狀分類). 장개빈파비풍적증상종대적방면분위경병화장병(張介賓把非風的症狀從大的方面分爲經病和臟病), 연후재파경병세분위경증화위증(然後在把經病細分爲經證和危證), 장병세분위초경증화위증(臟病細分爲稍經證和危證). 진관경병출현어지체(盡管經病出現於肢體), 이장병출현정신이상(而臟病出現精神異常), 단시경병여장병균유경증화위증(但是經病與臟病均有經證和危證). 저일주장시흔유지이성적. 대중풍적치료(對中風的治療), 이연대체상견지료금원이전적치료방법. 기용신한혹신온거풍화담(旣用辛寒或辛溫去風化痰), 혹용신온발한(惑用辛溫發汗), 혹용고한공리등(或用苦寒攻裏等). 장개빈지출상술방법대원기쇠약적중풍부적합사용(張介賓指出上述方法對元氣衰弱的中風不適合使用), 차장수신지출차시거풍치법실제상부적합내용풍이적합어외풍적치료(且張壽신指出此時去風治法實際上不適合內風而適合於外風的治療). 장개빈인위비풍적원인시진양여진음지허이불시풍담(張介賓認爲非風的原因是眞陽與眞陰之虛而不是風痰), 진관시급성기(盡管是急性期), 여과몰유담증(如果沒有痰證), 타견결반대사용거담지법(他堅決反對使用祛痰之法). 재중풍치료상(在中風治療上), 장개빈인위한다(張介賓認爲汗多), 소변소(小便少), 시진액부족소치(是津液不足所致), 소이수유열증역불요사용삼리지법, 병지출유뇨증시신허소치적위증(幷指出遺尿症是腎虛所致的危證), 종이진일보강조료진액적중요성(從而進一步强調了津液的重要性).

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.17.1-17.1
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• 2009

발포금속은 1948년에 Sosnik에 의해 알루미늄에 수은을 증발시키는 방법으로 발포 알루미늄을 제조한 이래, 1951년 Elliot에 의해 진보된 방식인 발포 매개체를 용탕에혼입하는 방법으로 발포금속을 제조하기 시작하였다. 현재 이들 선진국가의 생산방법 및 현황은 균질 기공의 조절, 연속주조 방식과 원가절감, 그리고 제조기술의 진보를 통하여 다양한 분야에 적용되고 있다. 그러나 실용화를 위해서는 요구특성을 만족하고 동시에 가격 경쟁력을 가진 제조기술의 보유 및 개발과 독특한 특성을활용한 새로운 적용 분야의 개척이 필요하다고 생각되며, 이를 위해 Harvard, MIT, Aachen, HMI 등 구미 유수 대학과 NASA, 미국방성등의 연구기관, ERG, 신강(新鋼) wire등 산업체를 중심으로제조 및 특성평가에 관한 기초연구와 활용방안이 활발히 모색중에 있다. 그리고 일부 자동차 생산 업체를중심으로 발포금속을 적용한 초경량, 에너지 절감형의 자동차 부품 소재,항공기 방열판 등에 대한 연구가 활발하게 진행되고 있다. 특히 금속 기체의 GASAR 공법은 Lotus 공법으로 Osaka 대학에서 개발되어 열교환기, 항공기, 방열기 등으로 응용이 확대되고 있다 국내에서 완제품생산은 실내장식용 복합패널로서 한소 프라임이 운영상의 문제로 생산을 중단하였으며, 유닉슨(주), 금강(주)에서 Batch식, 금성산업에서 Pot식이 일부 생산 및 연구가 진행되었으나 현재는 본연구실의 협조로 (주) 폼텍에서 발포패널을 주로 생산하고 있고 (주)드림메탈과 (주)아크로폼텍에서일부 생산되고, (주)동일알루미늄에서는 폐 scrap을 이용한 발포 Al 제조가 연구단계에 있다. 생기원에서는 분말 가열 흡음패널이 개발되었으나 강도와 내열성이 낮아 이들 특성을 향상시크는 연구가 진행중이다. 이들 제품은 성능상으로는 동양강판의 흡음패널과 KIMM의 필터용은연구개발이 낮은 수준이며, 본 연구팀과 공동 개발한 (주)폼텍의 복합패널은 10여 가지의 실용특허로 건축마감재로서 오히려 선진국수준을능가한 상태이다, 한편, 발포금속 기능성 개발은, 이들이 가지고 있는 우수한 특성 때문에 군수용으로부터 민수 산업용까지 전분야에 적용이 가능한 소재이므로 수요처를확장하고 있으므로 제품의 균질성, 안정성과 기능성 개발 향상을 위해 지속적이고 체계적인 연구가 필요하다고 생각된다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1099-1107
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• 2013

This study proposes a weight reduction design for urban transit, specifically, a Korean EMU carbody made of aluminum extrusion profiles, according to size optimization and useful material changes. First, the thickness of the under-frame, side-panels, and end-panels were optimized by the size optimization process, and then, the weight of the Korean EMU carbody could be reduced to approximately 14.8%. Second, the under-frame of the optimized carbody was substituted with a frame-type structure made of SMA 570, and then, the weight of the hybrid-type carbody was 3.8% lighter than that of the initial K-EMU. Finally, the under-frame and the roof-panel were substituted with a composite material sandwich to obtain an ultralight hybrid-type carbody. The weight of the ultralight hybrid-type carbody was 30% lighter than that of the initial K-EMU. All the resulting carbody models satisfied the design regulations of the domestic Performance Test Standard for Electrical Multiple Unit.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.197-198
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• 2006

본 연구에서 개발하는 성형렌즈는 그림1과 같이 한쪽 면이 비구면인 평볼록 형상이다. Glass렌즈의 고온압축성형을 위해서는 초정밀 가공기술로 제작된 성형Mold가 필요하며, Mold재질에 따른 성형기술의 확립이 필수적이다. 또한, 성형Mold의 표면과 융착반응이 없는 Glass소재가 요구된다. 본 실험을 위한 성형Mold는 코발트(Co) 함량 0.5 %의 초경합금(WC; 일본, Everloy社, 002K)을 초정밀 연삭가공하여 제작하였다. Glass소재는 전이점(Transformation Point; Tg) $572\;^{\circ}C$,항복점(Yielding Point; At) $630\;^{\circ}C$의 열적 특성을 갖는 K-BK7(일본, Sumita社)을 사용하였으며, d선에서 굴절률 및 아베수는 각각 1.51633, 64.1이다. 비구면 Glass렌즈 성형은 GMP(Glass Molding Press; 일본, Sumitomo社, Nano Press-S)장비를 사용하여 성형온도 $625\;^{\circ}C$, 서냉온도 $550\;^{\circ}C$로 고정하고 성형압력를 200-800 N 범위에서 변화시켰다. 표 1에 성형변수로 사용한 서냉속도와 서냉전환온도 조건을 나타낸다. 표1과 같이 각 서냉조건별로5장의 렌즈를 성형 후 특성값이 평균치에 가까운 3장을 선별하여 그 특성을 비교하였다. 각 조건에 따른 성형렌즈의 형상정도(일본, Panasonic社, UA3P, 자유곡면형상측정기), 두께(일본, Mitutoyo社, MDC-25M, 마이크로메터), 굴절률(일본, Shimatus社, KPR-200, 정밀굴절률측정기) 및 MTF[해상도](독일, Trioptics社, Image Master HR, MTF-Field)를 측정하여 각각의 광학적 특성을 비교 평가하였다. 비구면 Glass렌즈 성형장비와 형상측정기를 그림 2, 3에 각각 나타낸다.

• Membrane Journal
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• v.16 no.1
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• pp.1-8
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• 2006

Nanofiber is a broad phrase generally referring to a fiber with diameter less than 1 micron. Various polymers have been successfully electrospun into nanofibers in recent years. These nanofibers, due to their high surface area and porosity, have a great potential for use as filter medium, adsorption layers in protective clothing, etc. Nanofiber filters will enable new levels of filtration performance in the field of air filtration. In particular, nanofibers provide marked increases in filtration efficiency at relatively small pressure drop in permeability. Therefore, nanofiber filters could be substituted for conventional filter market due to the easy application of process and the possibility of coating to micron-sized non-woven sheets. This review is discussed on the trend of researche and development related to nanofiber filter including future marketability.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.56-60
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• 2018

There have been a lot of study to improve the performance of membrane filters as the removal of particulate matter has been of great interest due to the negative effects. Among the membrane fabrication techniques, the electrospinning technique is the most promising because it can produce uniform fibers ranging from nano to micrometer size. The electrospun membranes will greatly improve the filtration performance due to the high ratio of surface area to volume and the high porosity. In the present study, polystyrene (PS) and cellulose acetate (CA) polymers were used to produce the membranes with carbon nanotube (CNT), showing the filtration performances were improved with the optimal amounts of CNT.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.1-8
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• 2007

The ultra-fine tungsten carbide(WC) powders have been actively used in the cemented carbides industry, because they have excellent mechanical properties such as high hardness, strength, and toughness. In this study, ultra-fine WC-Co alloys powders have been fabricated by thermochemical and thermomechanical process such as spray conversion process or high energy ball milling. The non-coated end-mill which is made of ultra-fine tungsten carbide is investigated by measuring cutting force, tool wear, tool life, and surface roughness profile according to cutting length. The machining test was conducted with high hardened workpiece and their performances are investigated in high speed cutting conditions. Also, the relationship between the machining characteristics and the Co contents are investigated under various high speed cutting conditions.

• Korean Journal of Optics and Photonics
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• v.33 no.5
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• pp.218-229
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• 2022

We have investigated reliable inspection methods for finding the defects generated during the manufacturing process of lightweight, large-aperture satellite telescope mirrors using silicon carbide, and we have measured the basic physical properties of the mirrors. We applied the advanced ceramic material (ACM) method, a combined method using liquid-silicon penetration sintering and chemical vapor deposition for the carbon molded body, to manufacture four SiC mirrors of different sizes and shapes. We have provided the defect standards for the reflectors systematically by classifying the defects according to the size and shape of the mirrors, and have suggested effective nondestructive methods for mirror surface inspection and internal defect detection. In addition, we have analyzed the measurements of 14 physical parameters (including density, modulus of elasticity, specific heat, and heat-transfer coefficient) that are required to design the mirrors and to predict the mechanical and thermal stability of the final products. In particular, we have studied the detailed measurement methods and results for the elastic modulus, thermal expansion coefficient, and flexural strength to improve the reliability of mechanical property tests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.277-286
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• 2020

This study aimed to examine bone health awareness and knowledge and the bone mass-improving behaviors of female nursing college students. The subjects were 172 nursing students attending nursing colleges. The data were collected from March 16 to April 4, 2020, by using bone health awareness, bone health knowledge, and bone mass-promoting behavior assessment tools. Descriptive statistics are presented, and t-tests, ANOVA, Pearson's correlation, and multi-regressions were used for data analysis. Students' bone health awareness was 1.79, bone health knowledge was 8.86, and bone mass-promoting behavior level was 2.78. There were significant negative correlations between bone mass-promoting behavior level and age of menarche (r = 0.21, p = .004) and sun exposure (r = 0.44, p < .000). Also, bone mass-promoting behavior level and knowledge of bone health were negatively correlated (r = 0.21, p = .005). Regression analysis showed that knowledge of bone health (β = 0.21, p = .005), age of menarche (β = 0.20, p = .005), and sun exposure (β = 0.38, p < .000) were significant predictors of bone mass-promoting behaviors and their variance explanation power was 20.6%. Based on these results, education to improve knowledge of bone health will help to improve bone health and increase bone mass-promoting behaviors among young women.