• 한국건축시공학회지
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• 제8권4호
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• pp.105-114
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• 2008

This study investigates the saturation level of surface dryness, quantity of adhesive mortar, and the alien substance content of recycled aggregates for concrete to develop an adequate quality testing method for understanding the properties of recycled aggregates, which differ greatly from preexisting aggregates. For tests that measure the saturation level of surface dryness, where detail methods are applied differently according to the tester, various testing methods from across world were compared and analyzed. This study revealed that when measuring the saturation level of surface dryness of a certain sample, aggregates must be supplemented immediately whenever the height of the sample becomes lower than the measuring mold, and allowing the tamper to free fall on the sample will provide the most accurate results. When measuring the quantity of adhesive mortar of recycled aggregates for concrete, an acid solution was used, and since the quantity of adhesive mortar increases as the particle sizes gets smaller, the sample for testing should represent the entire granularity. Sulfuric acid solution is adequate for immersion, and the concentration should be 20% for best results. According to the alien substance content measurement, which was examined by the naked eye, the error range caused by the difference in particle size was neglectable, and therefore the sample should be $2.5{\sim}5.0mm$ in size concerning the accuracy and measuring time. Also, for coarse recycled aggregates, the sample should amount to 1kg for measuring alien substance content by the naked eye, which proves that assortment by the naked eye is the most adequate method for measuring the alien substance content of a recycled aggregate.

• 한국식품영양학회지
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• 제26권4호
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• pp.700-705
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• 2013

본 연구는 저장 기간 및 온도에 따른 방울토마토와 양상추의 미생물 종류와 성장 패턴 및 품질특성을 구명하였다. 방울 토마토와 양상추를 각각 $5^{\circ}C$, $10^{\circ}C$와 $15^{\circ}C$ 저장조건에서 1주일 간격으로 pH, 색도, 미생물 종류와 성장 패턴을 조사하였다. 방울토마토와 양상추 모두 저장 초기에 비해 저장기간 및 저장온도가 증가할수록 유기산 성분 용출이나 젖산균 증식으로 인해 pH 감소가 일어난 것으로 나타났다. 방울토마토는 저장기간에 따라 색도 변화에 차이를 보였는데, 특히 저장기간 21일째에 전 온도에서 저장 초기에 비해 명도, 적색도 및 황색도 모두 감소하였다. 양상추는 저장기간이 증가할수록 호흡에 의한 산화적 갈변으로 인해 명도가 감소하였고, 특히 $15^{\circ}C$에서 저장한 경우에 적색도와 황색도가 유의적으로 증가한 것으로 나타났다. 저장기간 및 온도에 따른 미생물의 종류 및 성장 패턴의 결과를 분석한 결과, 방울토마토와 양상추는 $10^{\circ}C$와 $15^{\circ}C$에서 저장한 경우, 곰팡이를 제외하고 총 균수, 대장균군수, 효모는 저장 초기에 비해 모두 증가한 것으로 나타났지만, 전 저장기간 및 저장온도에서 대장균과 황색포도상구균은 검출되지 않았다. 본 연구 결과, 방울토마토와 양상추는 저장기간 및 저장온도에 따라 품질과 미생물의 생장에 영향을 미치므로 $10^{\circ}C$와 $15^{\circ}C$에 비해 $5^{\circ}C$에서 7일 이하로 저장하였을 때, 품질과 미생물 수 변화가 적었으므로, 이점을 고려할 때 본 연구결과와 같은 적절한 저장기간 및 저장 온도를 유지한다면 품질의 안전성을 확보하여 신선한 품질을 유지할 수 있을 것이라 사료된다.

• 구강회복응용과학지
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• 제31권3호
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• pp.178-185
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• 2015

목적: 본 연구에서는 Simplant와 R2GATE 두 가지 수술용 가이드 시스템의 인터페이스(interface)에 대한 만족도, 제작된 수술용 가이드의 디자인과 편의성, 수술용 가이드 활용 시 중요도에 대한 만족도를 설문조사하여 비교평가 하고자 하였다. 연구 재료 및 방법: 두 가지 시스템으로 제작된 수술용 가이드(surgical guide)를 치아모형에 각각 장착한 상태에서 임플란트 수술 과정을 모의하였다. 모의 수술이 끝난 뒤 연구대상에게 만족도에 관한 설문지를 작성하도록 하였다. 작성된 설문지를 회수하여 각 문항에 대한 데이터를 정리하고 통계 프로그램 SPSS 20.0 (IBM)를 이용하여 분석하였다. 결과: 전체적인 만족도는 R2GATE 군($7.33{\pm}1.26$)이 SimPlant 군($6.67{\pm}1.26$)보다 더 높은 것으로 나타났다(${\alpha}$ = 0.05). 결론: R2GATE 시스템으로 제작된 수술용 가이드는 임상에 널리 사용 할 만 한 사용자의 만족도를 나타내었다. 또한, R2GATE 시스템으로 제작된 수술용 가이드는 drill의 길이와 방향을 동시에 guide할 수 있어 임플란트 식립 경험이 부족한 초심자에게 적극 추천된다.

• 대한소아치과학회지
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• 제31권1호
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• pp.66-78
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• 2004

초기의 접착 시스템은 여러 단계의 술식을 필요로 하였으며 술자의 기술과 재료의 성질에 크게 좌우되었으나 최근 산부식, priming, adhesive를 한번에 적용할 수 있는 all-in-one adhesive system이 등장하였다. 치과에서의 vibration의 이용은 치석의 제거 및 접착제의 점도를 낮추는데 이용되어왔으며 vibration은 접착제의 흐름성을 향상시켜 film thickness를 낮추어 수복물 주위의 미세누출을 줄이는데 도움을 준다. 이에 저자들은 all-in-one adhesive system에서 vibration이 법랑질과 상아질의 접착강도와 레진침투에 미치는 효과를 알아보고자 하였다. 법랑질 시편은 발거 후 실온에서 0.1% thymol 용액에서 보관된 30개의 건전한 사람의 대구치를 무작위로 10개씩 세군으로 나누고 근원심 방향으로 두 부분으로 분리하여 각각은 같은 접착제를 사용하고 초음파진동여부를 다르게 하였고, 아크릴레진을 이용하여 직경 1-inch의 PVC관에 매몰한 후 협설면이 아크릴봉과 동일한 높이가 되도록 220-, 600-grit 연마지로 순차적으로 연마하였고 군당 10개씩 여섯 군으로 분류하였다. 1군과 2군은 Prompt L-Pop(3M-ESPE, Seefeld, Germany), 3군과 4군은 One-Up Bond F(Tokuyama Corp., Tokyo, Japan), 5군과 6군은 AQ bond(Sun Medical Co., Kyoto, Japan)를 제조사의 지시에 따라 도포하였다. 2군, 4군, 6군은 초음파 치석제거기를 이용하여 치면에 대고 15초간 진동을 가한 후 광중합하였다. 상아질 시편은 치관부 법랑질을 제거한 후 상아질면을 아크릴 봉과 동일한 높이가 되도록 하고 법랑질 시편과 동일하게 처리하였다. 이후 직경 2mm, 높이 3mm의 Teflon mold(Ultradent, U.S.A.)를 이용하여 복합레진을 충전한 후 40초씩 두 번에 나누어 광중합한 후 24시간동안 실온에서 증류수에 보관하였다. 열순환 시행한 후, 만능측정기(Instron 4465)로 전단결합강도를 측정하였으며 Resin tag의 양상을 비교하기 위해 각 군의 시편의 치질을 완전히 용해시킨 후 표면을 주사전자현미경사진으로 관찰하여 다음과 같은 결과를 얻었다. 1 법랑질에서 초음파 진동을 가한 군(2, 4, 6군)은 가하지 않은 군(1, 3, 5군)에 비해 평균 전단결합강도가 높게 나타났다. 그 차이는 Ad bond 군을 제외하고 통계적으로 유의하였다(p<0.05). 2. 상아질에서 초음파 진동을 가한 군(2, 4, 6군)은 가하지 않은 군(1, 3, 5군)에 비해 평균 전단결합강도가 높게 나타났다. 그러나 그 차이는 One-Up Bond F군을 제외하고는 통계적으로 유의한 차이가 없었다. 3. 전자 현미경 관찰에서 초음파 진동을 가한 군에서 더 많은 법랑질의 소실과 상아질에서 resin tag의 길이가 길었고 lateral branch의 수도 많이 관찰되었다.

• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.490-496
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• 1998

Random amplified polymorphic DNA (RAPD) markers were used to survey genetic variability among 34 Botrytis cinerea isolates from nine different host plants in Korea. For RAPD analysis, 115 arbitrary decamer primers were initially screened for polymorphic major DNA bands with 11 representative B. cinerea isolates. Eleven primers that initially detected polymorphisms were tested a second time with additional 23 isolates of B. cinerea as well as one isolate of Botrytis squamosa as an outgroup. The RAPD analyses revealed that all isolates except one showed different molecular phenotypes. Dendrograms obtained from dissimilarity matrices using the unweighted paired group method of arithmetic means (UPGMA) showed the 36.4% to 90.0% similarity among all B. cinerea isolates. The B. squamosa isolate showed the least similarity to all B. cinerea isolates. The cluster analyses indicated no correlation among all the characteristics examined including molecular phenotypes, host and geographic origins, year of isolation, or pathogenicity. The RAPD data suggest that a high level of genetic variation exists among Korean populations of B. cinerea and it seems to be caused by heterokaryosis among preexisting molecular phenotypes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.223.2-223.2
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• 2015

Polyurethane acrylate (PUA) has been introduced to utilize as a mold material for sub-100 nm lithography as it provides advantages of stiffness for nanostructure formation, short curing time, flexibility for large area replication and transparency for relevant biomedical applications. Due to the ability to fabricate nanostructures on PUA, there have been many efforts to mimic extracellular matrix (ECM) using PUA especially in a field of tissue engineering. It has been demonstrated that PUA is useful for investigating the nanoscale-topographical effects on cell behavior in vitro such as cell attachment, spreading on a substrate, proliferation, and stem cell fate with various types of nanostructures. In this study, we have conducted surface modification of PUA films with micro/nanostructures on their surfaces using plasma treatment. In general, it is widely known that the plasma treated surface increases cell attachment as well as adsorption of ECM materials such as fibronectin, collagen and gelatin. Effect of plasma treatment on PUA especially with surface of micro/nanostructures needs to be understood further for its biomedical applications. We have evaluated the modified PUA film as a culture platform using adipose derived stem cells. Then, the behavior of stem cells and the level of adsorbed protein have been analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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• pp.112-116
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• 2007

If any of the set parameters such as the environment temperature, mold temperature are not maintained at a consistent level, the fail rate of injection molding products is increased. The price of the injection molding machine is very high, so in order to maximize the utilization of the machine that is required the production of a number of different products with minimum fail rate using a single machine. To prevent the defect products by an inspection process with perfect quality is very important to minimizing production of defect products in the molding process. Vision inspection systems are widely utilized in various manufacturing industries for quality assurance purposes. The vision inspection system consists of CCD camera and lighting system to capture the image of the subject of inspection, an image comparison algorithm using to determine the pass/fail of the products, and mechanical devices for the operation of the whole system. This research focuses on the development of the vision inspection system to process the inspection of an automobile parts. We developed a mechanical devices for the inspection of the injection molding products and an image comparison algorithm to determine the pass/fail result of the inspection based on the molding image and the accepted product image.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.283-293
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• 2016

Owing to an increase in the air tightness of recent buildings, the natural ventilation rate was significantly lowered and the removal of accumulated moisture became difficult in these buildings. The hygrothermal performance of these buildings should be carefully considered to provide comfortable indoor environment by removing the moisture condensation risk and the mold growth potential. In this study, hygrothermal performance of two selected wall structures was investigated based on WUFI simulation program. The results displayed that the indoor temperature had impact on the moisture accumulation in the insulation layer for both modeled walls, showing that lower indoor temperature resulted in higher moisture accumulation, especially in the wood frame structure. Also, the yearly moisture accumulation profile exhibited a downward shift throughout the year by adding a vapour retarder with a lower sd-value. In addition, both of the two walls have condensation risk in winter, due to low temperature level. The wood frame structure has a bigger fluctuation and higher condensation risk than the concrete structure.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.69-75
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• 2005

In order to improve the reliability of high voltage rotating machines and mold transformers, it is necessary to understand the breakdown mechanism and life assessment of the high voltage winding parts. Especially the on-line PD test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting the electrical machines, this method has been proven the major testing technology. Capacitive couplers have been the most widely used sensors for the on-line partial discharge detection in rotating machines nowadays. This paper deals with the electrical characteristics and long-term reliability of a ceramic coupler(CC), which can be easily mounted into high voltage input terminal part, has been developed and tested to continuously measure PD activity during operating condition. This paper presents electrical characteristics (dielectric loss angle, capacitance, PD inception level, breakdown voltage, and frequency response bandwidth) and long-term life test result of the developed 6.6 kV class on-line ceramic coupling sensor. It was found that this sensor had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz. Also, the voltage life of the 6.6kV class ceramic coupler was calculated over 60 years.

• 대한기계학회논문집A
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• 제32권2호
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• pp.186-193
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• 2008

[ $Moir{\acute{e}}$ ] interferometry is an optical method, providing whole field contour maps of in-plane displacements with high resolution. The demand for enhanced sensitivity in displacement measurements leads to the technique of microscopic $moir{\acute{e}}$ interferometry. The method is an extension of the $moir{\acute{e}}$ interferometry, and employs an optical microscope for the required spatial resolution. In this paper, the sensitivity of $moir{\acute{e}}$ interferometry is enhanced by an order of magnitude using an immersion interferometry and the optical/digital fringe multiplication(O/DFM) method. In fringe patterns, the contour interval represents the displacement of 52 nm per fringe order. In order to estimate the reliability and the applicability of the optical system implemented, the measurements of rigid body displacements of grating mold and the coefficient of thermal expansion(CTE) for an aluminium block are performed. The system developed is applied to the measurement of thermal deformation in a flip chip plastic ball grid array package.