• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.353-356
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• 2002

In this study, the clay samples collected in the area Mokpo carry out laboratory soil test. Under three different curing $temperature-20^{\circ}C,\;50^{\circ}C,\;80^{\circ}C$ and 4 terms of curing day -1day, 7days, 14days, 40days for each, the remolded and reconsolidated samples had been made. To find out an aging effects and geotechnical characteristics between undisturbed samples and reconsolidated samples, laboratory tests were preformed. In the results, it was found that mechanical properties of undisturbed natural samples were similar to high temperature reconsolidation clay. The curing temperature influence on simulating aging effect more than the curing day does and the best curing condition are $80^{\circ}C$, 27days.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.754-761
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• 2008

In general, stress measurement of existent shotcrete lining be used by pressure cells. but, measuring instrument is lost by high pressure at shotcrete lining construction and pressure cell's measurement value have to low believability by natural conditions like curing temperature. In this study, proposed techniques to measure without utilizing sensitive stress sensor in natural condition at point that want stress of shotcrete lining after shotcrete lining construction. Executed numerical analysis to forecast stress level that interact in tunnel shotcrete lining, measured strain of hole by load action through hole in shotcrete lining. 3D FEM(finite element method) is enforced through various parameters curing time of shotcrete lining, thickness, load condition. Different model cases applied by parametic study. As analysis result, it could grasp development possibility of method that propose this time because it could examine corelation with strain by near hole of shotcrete lining and stress about load condition.

• 전기학회논문지P
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• 제65권1호
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• pp.53-56
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• 2016

Because of the low pollution resistance of the porcelain electrical insulator itself, in this work the anti-pollution performance of insulator was improved by using the functional coating. The ceramic substrates that components were same as the porcelain electrical insulator were used in this experiment. The functional films were coated on the ceramic substrate by using a spray coating method, and then the coated substrate were annealed under different coating condition such as natural curing and annealing temperature of $200^{\circ}C$, $300^{\circ}C$ and $400^{\circ}C$. Then, the contact angles of the coated surfaces were measured and the minimum angle ($8.3^{\circ}$) was obtained at $400^{\circ}C$. The anti-contamination properties were measured, revealing that as the contact angle decreased, the anti-contamination properties improved. The hardness and adhesion were small at the natural curing condition however the excellent mechanical properties were obtained under higher temperature annealing.

• Journal of Information Display
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• 제4권1호
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• pp.17-23
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• 2003

A thermoset type anisotropic conductive adhesive film (ACAF) comprising epoxy resin and natural butyl rubber (NBR) as the binder, micro-encapsulated imidazole as the curing agent, and Ni/Au coated polymer bead as a conductive particle has been studied. These films have been prepared to respond to requirements such as improved contact resistance, current status less of than 60 ${\mu}m$ and reliability. These films can also be used for connection between the ITO glass for LCD panel and the flexible circuit board. The curing conditions for the connection were 40, 20 and 15 seconds at 150, 170 and 190 $^{\circ}C$, respectively. The initial contact resistance and adhesion strength were 0.5 ${\Omega}/square$ and 0.4 kg/cm under the condition of 30 kgf/$^{cm}^2}$, respectively. After completing one thousand thermal shock cycling tests between -15 $^{\circ}C$ and 100 $^{\circ}C$, the contact resistance was maintained below 0.7 ${\Omega}/square$. Durability against high temperature (80$^{\circ}C$) and high humidity (85 % RH) was also tested to confirm long-term stability (1000 hrs) of the conduction.

• 한국지반공학회논문집
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• 제19권2호
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• pp.7-14
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• 2003

본 연구는 광양만 지역과 목포 남악지역의 점토를 이용하여 양생온도를 20$\times$, 50$\times$ , 80$\times$로 달리하고 각각의 온도에서 양생기간을 1일, 7일 14일, 40일로 하여 재성형.재압밀 시료를 제작하여 양생온도.양생기간이 연대효과 재현에 어떤 영향이 있는지를 밝히고, 불교란시료와 재압밀된 점토의 역학적 특성과 연대효과의 특성을 알아보기 위하여 1축압축시험, 3축압축시험 그리고 표준압밀시험을 실시하였다. 그 결과 압축지수비는 원지반점토의 연대효과를 나타내는데 유용한 지수임을 확인할 수 있었으며 또한 고온으로 양생한 점토가 연대효과를 잘 표현하고 연대효과의 재현에 필요한 최적의 양생온도는 80$\times$ 정도 부근이고 양생기간은 27일정도 임을 알 수 있었다.

• 콘크리트학회논문집
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• 제11권4호
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• pp.13-20
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• 1999

Recently, the study for practical construction application no recycled aggregate concrete is actively being proceeded, on the purpose of technical development for recycling on the construction waste concrete occurred at the time of destruction of building construction by the rapid increase of building wastes and exhaustion of natural aggregates. But, the durability of investigation with all sorts of fluidity and engineering property for application recycled aggregate concrete to practical construction must be done at the same time. Especially, because of the real condition for chemical attack of concrete construction by the acid rain, acidification of soil, deepening of air pollution and dirty water etc. being come to the fore a serious problem, the study on the chemical soundness of concrete durability must be accompanied. This study is composed as: I series: Analysis for chemical soundness of aggregates. II series: Analysis for chemical soundness of natural and recycled aggregate concrete against $Na_2$$SO_4$ solution in drying and wet curing condition ($at20~80^{\circ}C$).

• 한국작물학회지
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• 제34권4호
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• pp.331-334
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• 1989

공시품종을 Burley 21로 하고, 수확한 후 건조실관리에 따른 건조부패엽 방지방법을 체계화하기 위하여 무가온과 가온조건으로 구분하였으며, 무가온건조에서는 달줄간격과 환기조건을 달리하여 처리하였고, 가온조건에서는 화력, 풍화력, 풍력으로 구분하여 처리하였던 바 실험 결과를 요약하면 다음과 같다. 1. 달줄간격을 넓힐수록 온도 차이는 없었으나 습도가 낮아져서 부패엽 발생이 크게 감소되었다. 2. 환기구에서는 온도가 2$^{\circ}C$, 습도가 2.3%가 각각 더 낮아서 밀폐구 보다는 부패엽이 20% 감소되었다. 3. 건조시 당일 25% 패수된 처리는 이후의 기상조건이나 건조실관리에 영향을 받지 않고 부패엽이 발생되지 않았다. 4. 부패시에 35$^{\circ}C$온도로 화력이나 풍화력을 24시간 처리한 구에서는 무퍼리보다 부패엽이 39.7, 47.4%가 각각 감소되었다. 5. 부패시에 48시간 풍격 처리구에서도 무처리보다 34%가 감소되어 건조실내 공기의 강재순환효과가 컸다.

• Current Research on Agriculture and Life Sciences
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• 제26권
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• pp.23-30
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• 2008

Pad-dry-cure 방식으로 ethylene cyanohydrin을 이용하여 견직물을 acrylonitrile화 시킬 때 건조 시간, curing 온도 및 시간, ethylene cyanohydrin 처리 농도, $ZnCl_2$ 처리 농도 등 조건 변화에 따른 변화와 반응양식을 규명하고자 하였다. 가공된 견직물의 FT-IR과 DSC 분석을 통하여 다음과 같은 결과를 얻었다. Curing을 $150^{\circ}C$에서 2분, ethylene cyanohydrin 처리 농도 5%, $ZnCl_2$ 처리농도 0.1%, 건조 온도를 $80^{\circ}C$로 하여 건조 시간 경과에 따른 견직물의 FT-IR 분석 결과, 건조 시간 경과에 따라 -OH($3,450cm^{-1}$) 특성 peak가 전부 장파장 쪽으로 shift 되어 나타났고, random coil에 의한 amide peak($1,663cm^{-1}$)는 단파장 쪽으로 shift되어 ${\beta}$-sheet peak($1,635cm^{-1}$)와 중복되어 나타났다. 건조를 $80^{\circ}C$에서 3분, curing을 $110^{\circ}C$에서 2.5분, $ZnCl_2$ 농도를 0.1%로 하여 ethylene cyanohydrin 처리 농도에 따른 가공 견직물의 FT-IR 분석에서 -OH ($3,450cm^{-1}$) 특성 peak에서 변화가 나타나 견직물의 -OH기가 반응에 관여하고 있는 것을 알 수 있었다. 위와 같은 조건으로 가공된 견직물의 DSC 분석에서 ethylene cyanohydrin 처리에 의해 견직물의 열분해 온도는 무처리의 $311^{\circ}C$에서 대략 $320^{\circ}C$로 상승하는 것으로 나타났다. 건조를 $80^{\circ}C$에서 3분, curing을 $110^{\circ}C$에서 2.5분, ethylene cyanohydrin 처리농도 5%로 하여 $ZnCl_2$ 처리 농도에 따른 가공 견직물의 FT-IR 분석에서는 촉매 처리농도 0.8%일 경우를 제외하고는 -OH($3,450cm^{-1}$) 특성 peak에서 대부분 무처리와 비슷한 결과를 보여 주고 있으나, 0.8%의 경우에는 peak에 큰 변화를 나타냈다. 같은 조건에서 가공된 견직물의 DSC 분석에서, ethylene cyanohydrin 처리에 의해 견직물의 열분해 온도는 촉매농도와는 관계없이 무처리($311^{\circ}C$)에 비해 가공 견직물(대략 $320^{\circ}C$)의 열분해 온도가 상승됨을 알 수 있었다. 건조를 $80^{\circ}C$에서 70초, ethylene cyanohydrin 처리농도 5%, $ZnCl_2$ 처리농도 0.8%, Curing 시간을 2.5분으로 하고 curing 온도를 각각 110, 120, 130, 140, 150, $160^{\circ}C$로 변화시켜 가공한 견직물의 FT-IR의 분석 결과, curing 온도 110, 150, $160^{\circ}C$에서 -OH특성 peak의 변화가 크게 나타났다. 같은 조건으로 가공한 견직물의 DSC 분석에서는 ethylene cyanohydrin 처리에 의한 견직물의 열분해 온도는 curing 온도에 상관없이 미처리구($311^{\circ}C$)에 비해 전부 열분해 온도(대략 $320^{\circ}C$)가 상승함을 알 수 있었다.

• Computers and Concrete
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• 제26권4호
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• pp.327-342
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• 2020

The objective of this study is to manufacture environmentally-friendly synthetic lightweight aggregates that may be used in the structural lightweight concrete production. The cold-bonding pelletization process has been used in the agglomeration of the pozzolanic materials to achieve these synthetic lightweight aggregates. In this context, it was aimed to recycle the waste fly ash by employing it in the manufacturing process as the major cementitious component. According to the well-known facts reported in the literature, it is stated that the main disadvantage of the synthetic lightweight aggregate produced by applying the cold-bonding pelletization technique to the pozzolanic materials is that it has a lower strength in comparison with the natural aggregate. Therefore, in this study, the metakaolin made of high purity kaolin and calcined kaolin obtained from impure kaolin have been employed at particular contents in the synthetic lightweight aggregate manufacturing as a cementitious material to enhance the particle crushing strength. Additionally, to propose a curing condition for practical attempts, different curing conditions were designated and their influences on the characteristics of the synthetic lightweight aggregates were investigated. Three substantial features of the aggregates, specific gravity, water absorption capacity, and particle crushing strength, were measured at the end of 28-day adopted curing conditions. Observed that the incorporation of thermally treated kaolin significantly influenced the crushing strength and water absorption of the aggregates. The statistical evaluation indicated that the investigated properties of the synthetic lightweight aggregate were affected by the thermally treated kaolin content more than the kaoline type and curing regime. Utilizing the thermally treated kaolin in the synthetic aggregate manufacturing lead to a more than 40% increase in the crushing strength of the pellets in all curing regimes. Moreover, two numerical formulations having high estimation capacity have been developed to predict the crushing strength of such types of aggregates by using soft-computing techniques: gene expression programming and artificial neural networks. The R-squared values, indicating the estimation performance of the models, of approximately 0.97 and 0.98 were achieved for the numerical formulations generated by using gene expression programming and artificial neural networks techniques, respectively.

• Computers and Concrete
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• 제19권5호
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• pp.443-449
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• 2017

Taking high geothermal tunnels as background, the deformation of concrete for shotcrete use was studied by simulating hot-humid and hot-dry environments in a laboratory. The research is made up by two parts, one is the influence of two kinds of high geothermal environments on the deformation of shotcrete, and the other is the shrinkage inhibited effect of fiber materials (steel fibers, polypropylene fibers, and the mixture of both) on the concrete in hot-dry environments. The research results show that: (1) in hot and humid environments, wet expansion and thermal expansion happened on concrete, but the deformation is smooth throughout the whole curing age. (2) In hot and dry environments, the concrete suffers from shrinkage. The deformation obeys linear relationship with the natural logarithm of curing age in the first 28 days, and it becomes stable after the $28^{th}$ day. (3) The shrinkage of concrete in a hot and dry environment can be inhibited by adding fiber materials especially steel fibers, and it also obeys linear relationship with the natural logarithm of curing age before it becomes stable. However, compared with no-fiber condition, it takes 14 days, half of 28 days, to make the shrinkage become stable, and the shrinkage ratio of concrete at 180-day age decreases by 63.2% as well. (4) According to submicroscopic and microscopic analysis, there is great bond strength at the interface between steel fiber and concrete. The fiber meshes are formed in concrete by disorderly distributed fibers, which not only can effectively restrain the shrinkage, but also prevent the micro and macro cracks from extending.