• 자원리싸이클링
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• 제32권6호
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• pp.10-17
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• 2023

칼슘실리케이트 시멘트(Calcium silicate cement, CSC)는 친환경 저탄소 시멘트로써 최근에 많은 연구가 진행되고 있다. 하지만 이산화탄소 반응 활성화와 시료 handling을 위하여 사전경화 단계를 진행하여야하는 어려움이 있다. 본 연구에서는 CSC에 칼슘설포아루미네이트(Calcium sulfoaluminate, CSA) 속경시멘트를 혼합하여 초기강도 발현으로 사전경화 없이 사용할 수 있는 CSC의 확대적용 가능성을 살펴보고자 하였다. 이를 위하여 이산화탄소 분위기에서 CSC 와 CSA 속경성 시멘트 혼합비율 변화에 따른 압축강도와 Q-XRD 광물특성 함량 변화를 측정하였다. 압축강도 측정결과, CSC 50% 조건에서 3일과 7일 압축강도가 각 각 14.18MPa과 22.98MPa로 1종시멘트 KS규격을 만족하였다. 광물특성 분석을 통하여 이산화탄소 반응생성물인 calcite 광물이 증가하여 강도발현에 기여했음을 알 수 있었다. 7일 경과 후에도 수화광물인 dicalcium silicate 및 yeelimite광물뿐 아니라, 이산화탄소와 반응하지 않은 rankiniten 및 pseudowollastonite 광물이 다량 관찰되어 7일이후의 강도발현 가능성을 확인하였다.

• 접착 및 계면
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• 제4권2호
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• pp.21-29
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• 2003

Hot AC anodising has been evaluated us pre-treatment for aluminium prior to structural adhesive bonding. Phosphoric and sulphuric acid hot AC anodising showed very promising adhesion promoter capabilities with durability comparable with the best standard DC anodising procedures. AC anodising does not required etching prior to anodising and offers u pre-treatment time down to 20 seconds. The interface/interphase between the aluminium substrate and the adhesive was investigated in order to get a better understanding of the involved adhesion mechanisms and to explain the long-tenn properties. The alkaline medium formed at the oxide layer/adhesive interface has been shown to induce a partial dissolution of the oxide layer leading to the formation of metallic ions which diffuse in the adhesive (EPMA measurements). The effect of diffusion of the Al ions on adhesion and joint durability is still uncertain but studies showed that pre-bond moisture affected the joints durability and to some extent the diffusion length. specially for DC anodised samples. So far no direct correlation could be established between the diffusion length d and the joints durability but new trials with better control over the elapsed time between bonding and adhesive curing are expected to help getting a better understanding of the involved mechanisms.

• 한국축산식품학회지
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• 제31권3호
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• pp.389-397
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• 2011

This study was conducted to examine the effect of salt concentration in soybean sauce (ganjang) on pre-rigor ground Hanwoo (Korean native cattle) muscle. Although adding soybean sauce reduced pH of pre-rigor Hanwoo muscle, it improved the water holding capacity (WHC), cooking loss, total protein solubility, myofibrillar fragmentation index (MFI), 2-thiobar-bituric acid (TBA) values, and textural properties by increasing salt concentration in the soybean sauce. In particular, adding soybean sauce inhibited lipid oxidation despite increasing salt concentration. An increased salt concentration in the soybean sauce in pre-rigor Hanwoo muscle tended to make the meat have lower lightness and higher redness and yellowness values. Although soybean sauce had a significantly lower pre-rigor salting effect than sodium chloride in terms of cooking loss and total protein solubility (p<0.05), soybean sauce improved myofibrillar fragmentation and lipid oxidation when compared with sodium chloride. Furthermore, no significant differences in textural properties were observed between adding soybean sauce and sodium chloride at the same salt concentrations. Therefore, soybean sauce can be a functional curing material for pre-rigor muscle.

• 한국재료학회지
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• 제4권5호
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• pp.574-580
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• 1994

본연구는 DSC (dynamic run)의 Barrett method Integral mdthod DGEBA/MDA/MN(malononitrile) DSC DSC pre exponential factor, kinetic parameter 들을 구할 수 있었다.

• 한국염색가공학회지
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• 제25권4호
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• pp.287-291
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• 2013

Nowadays, terms such as 'Smart Textile', 'Intelligent Textile' and 'Wearable Computing' are commonly used in everyday contexts. And radio-frequency identification (RFID) is the use of a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking. These products are required technologies which are textile treatments, printing, ink, etc. Durability of textile substrates is an essential marker for conductive ink printing process. Especially, heat stability is important, since conductive ink should be processable (annealing, curing) at temperatures below $150^{\circ}C$. This study was application of RFID on textiles. The textile pre-treatment processes should be carried out to use RFID antenna on textiles.

• Fisheries and Aquatic Sciences
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• 제3권3_4호
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• pp.200-204
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• 2000

To investigate pre-salting conditions in the preparation of salted anchovy from large anchovy, anchovy were salted with various salt concentration and stored at $5^{\circ}C$ and $20^{\circ}C$ for 10 days. Moisture content decreased with the increase of salt and the salinity increased in proportion to salt concentration at $20^{\circ}C$. Total nitrogen decreased slightly as the increase of salt concentration during pre-salting at $20^{\circ}C$. The nitrogenous components such as amino nitrogen and extractable nitrogen were invariable or decreased until 7 days in salt concentration over $25\%$ during pre-salting at $5^{\circ}C$. These results imply that soluble nitrogen with moisture run out of anchovy body in high salt concentration and the hydrolysis was inhibited by salt over $25\%$ at $5^{\circ}C$. VBN content were constant in salt concentration over $25\%$ until 7 days, regardless of curing temperature. The POV were under the influence of salt concentration and temperatures. We concluded that the optimal condition for preparation of salted anchovy were pre-salting with salt over $25\%$ at $5^{\circ}C$ for 7 days.

• 접착 및 계면
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• 제12권4호
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• pp.105-110
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• 2011

폴리에스터/멜라민 경화형 도료는 기계적 물성, 내화학성 및 내마모성 등이 우수하여 pre-primed 도료 및 pre-coated metal에 널리 사용되고 있다. 그러나, 폴리에스터 수지 도료의 경화 도막은 강인하지만 유연성과 성형성이 낮은 문제점을 갖고 있다. 본 연구에서는 polycarbonate diol의 long alkyl chain을 폴리에스터 분자 구조 내에 연결시켜 경화 도막의 성형성을 개선하고자 하였으며, 성형성이 개선된 폴리에스터 도료의 선도장 강판용 도료의 적용 가능성을 확인하였다. 또한, 폴리카보네이트디올 분자량이 경화 도막 물성에 미치는 영향을 평가하고자 인장강도와 점탄성을 측정하였으며, 성형성을 확인하고자 drawing test를 실시하였다.

• 한국축산식품학회지
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• 제37권1호
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• pp.105-113
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• 2017

The effect of fermented spinach extracts on color development in cured meats was investigated in this study. The pH values of raw cured meats without addition of fermented spinach extract or nitrite (negative control) were higher (p<0.05) than those added with fermented spinach extract. The pH values of raw and cooked cured meats in treatment groups were decreased with increasing addition levels of fermented spinach extract. The lightness and yellowness values of raw cured meats formulated with fermented spinach extract were higher (p<0.05) than those of the control groups (both positive and negative controls). The redness values of cooked cured meats were increased with increasing fermented spinach extract levels, whereas the yellowness values of cooked cured meats were decreased with increasing levels of fermented spinach extract. The lowest volatile basic nitrogen (VBN) and thiobarbituric acid reactive substances (TBARS) values were observed in the positive control group with addition of nitrite. TBARS values of cured meats added with fermented spinach extract were decreased with increasing levels of fermented spinach extract and VBN values of curing meat with 30% fermented spinach extract was lower than the other treatments. Total viable bacterial counts in cured meats added with fermented spinach extract ranged from 0.34-1.01 Log CFU/g. E. coli and coliform bacteria were not observed in any of the cured meats treated with fermented spinach extracts or nitrite. Residual nitrite contents in treatment groups were increased with increasing levels of fermented spinach extract added. These results demonstrated that fermented spinach could be added to meat products to improve own curing characteristics.

• 한국해양공학회지
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• 제18권1호
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• pp.53-62
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• 2004

The Purpose of this study is to recycle the waste concrete, which is generated in huge quantities, from construction works. in order to achieve this goal, it is important to determine the compressive strength, workability, slump, and ultrasonic velocity of recycled aggregate concrete. Thus, several experiment parameters are considered, such as water-cement ratios, sand percentage, and fine aggregate composition ratios, in order to apply the recycled aggregate concrete to pre-cast artificial fishing reefs. From the results, it has been shown that the proper mix designs for reef concrete are W/C=45%, S/a=50%, SR50:SN50 in recycled sand and natural sand mix combination case, W/C=45%, S/a=50%, SC50:SN50 in crushed sand and natural sand mix combination case, W/C=45%, S/a=50%, SR50:SC50 in recycled sand and crushd sand mix combination case. Also, this study shows that the shape and surface roughness of fine aggregate particles have an effect on the strength, slump, ultrasonic velocity of tested concrete, and the compressive strength ratios of 7days' and 90days' curing ages of recycled aggregate concrete are about 70% and 110% of 28days' curing age.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.827-834
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• 2011

Epoxy/graphite/expanded graphite composites have been prepared in various weight ratios and thermal degradation and electrical properties were estimated in order to use for the bipolar plate materials in PEMFC. Thermogravimetric analysis (TGA) showed that the epoxy/graphite system cured by a curing agent GX-533 was most proper because its weight loss until $80^{\circ}C$ at which PEMFC would be operated was 0.3 wt%, and differential scanning calorimetry (DSC) analysis showed its cure temperature would be sufficient at $80^{\circ}C$. The activation energy for the cure reaction was 132.0 kJ/mol and the pre-exponential factor was $1.76{\times}10^{17}min^{-1}$. Electrical conductivity on the surface of the bipolar plate prepared under a pressure of 200 $kgf/cm^2$ was increased from 4 to 25 $S/cm^2$ by increasing expanded graphite (EG) content from 50 phr to 90 phr. The percolation threshold was initiated around 75 phr and the corrosion rate at 80 phr was 1.903 $uA/cm^2$.