• 마이크로전자및패키징학회지
• /
• 제21권4호
• /
• pp.51-56
• /
• 2014

가격적 경쟁력을 가지는 Ag 코팅 Cu 플레이크 함유 도전성 페이스트를 제조하여 경화조건에 따른 열전도도 및 전기전도도 값의 변화를 측정하였다. 대기 중에서 경화시킨 시편의 경우 경화시간이 30분에서 60분으로 증가됨에 따라 열전도도가 증가하는 경향이 관찰되었다. 60분의 동일한 경화시간 조건에서는 질소 중 경화 시편이 대기 중 경화 시편보다 향상된 열전도도 값을 나타내었다. 그 결과 질소 중에서 60분간 경화시킨 Ag 코팅 Cu 플레이크 페이스트는 순수 Ag 플레이크가 함유된 페이스트가 나타내는 열전도도에 근접하는 열특성을 나타내었다. 한편 대기 중 경화 시편의 경우 경화시간이 30분에서 60분으로 증가됨에 따라 비저항 값이 더욱 증가하는 경향이 관찰되었나, 60분의 동일한 경화시간 조건에서 질소 중 경화 시편은 대기 중 경화 시편에 비할 수 없을 만큼 개선된 비저항 값($7.59{\times}10^{-5}{\Omega}{\cdot}cm$)을 나타내었다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2012년도 추계 학술논문 발표대회
• /
• pp.255-257
• /
• 2012

Epoxy resin without any hardener can harden in the presence of hydroxide ions in cement mortars and concretes at ambient temperature. The purpose of present study is to examine the hardening properties of hardener-free epoxy-modified mortars by curing conditions. The hardener-free epoxy-modified mortars using diglycidyl ether of A epoxy resin are prepared with various polymer-cement ratios, and subjected to initial moist/dry curing, initial steam(90℃) curing, initial steam/heat(80℃, 100℃) curing.As a result, degree of hardening of epoxy resin in initial moist/dry cured, initial steam cured and initial steam/heat(80℃) cured hardener-free epoxy-modified mortars is decreased with increasing polymer-cement ratio. However, it is markedly improved with additional dry-curing periods. On the other hand, regardless of the polymer-cement ratio and dry curing periods, degree of hardening of hardener-free epoxy-modified mortars with initial steam/heat(100℃) cure is over 95%.

• 한국건축시공학회지
• /
• 제3권4호
• /
• pp.87-94
• /
• 2003

This study is to investigate the temperature hysteresis and development of compressive strength due to the curing conditions and to evaluate the optimum curing condition of test specimens showing the same development of strength to that of real structures in cold weather. The results of temperature curve with curing conditions in mock-up tests showed the trend of decrease plain concrete with insulation form, plain concrete with heating, concrete with accelerator for freeze protection, and control concrete in turn. The strength development of plain concrete of inside and outside of shelter showed the very slow strength gains due to early freezing, but that of concrete with accelerator for freeze protection showed the gradual increase of strength with time. From this, it is clear that accelerator for freeze protection has the effects of refusing the freezing temperature and accelerating the hardening under low temperature. Strength test results of small specimens embedded in members and located in insulation boxes at the site are similar to that of cores drilled from the members at the same ages, thus it is clear that these curing methods are effective for evaluating in-place concrete strength

• 한국건설순환자원학회논문집
• /
• 제9권3호
• /
• pp.260-267
• /
• 2021

이 연구의 목적은 양생조건이 물-결합재비가 15%인 알칼리 활성 슬래그 기반 복합재료의 압축 및 인장거동에 미치는 영향을 실험적으로 조사하는 것이다. 이를 위하여 양생 조건을 다르게 하여 실험체를 제작한 후 압축강도와 인장실험을 수행하였다. 실험 결과 고온 양생과 기중 양생을 적용함에 따라 매트릭스의 압축강도와 균열강도는 감소한 반면 인장변형성능은 증가하는 것으로 나타났다. 또한 고온 양생과 기중 양생을 통해 복합재료의 균열 간격과 균열폭이 감소하는 것으로 나타났다.

• 한국전기전자재료학회논문지
• /
• 제37권1호
• /
• pp.56-62
• /
• 2024

By introducing curing kinetics and chemo-rheology for the epoxy resin formulation for ultra-high voltage gas insulated switchgear (GIS) Insulating Spacers, a study was conducted to simulate the curing behavior, flow and warpage analysis for optimization of the molding process in automatic pressure gelation. The curing rate equation and chemo-rheology equation were set as fixed values for various factors and other physical property values, and the APG molding process conditions were entered into the Moldflow software to perform optimization numerical simulations of the three-phase insulating spacer. Changes in curing shrinkage according to pack pressure were observed under the optimized process conditions. As a result, it was confirmed that the residence time in the solid state was shortened due to the lowest curing reaction when the curing holding pressure was 3 bar, and the occurrence of deformation due to internal residual stress was minimized.

• 대한토목학회논문집
• /
• 제44권3호
• /
• pp.283-290
• /
• 2024

현재 우리나라의 순환골재의 품질기준은 천연골재와 거의 동등한 수준으로 매우 높기 때문에 재생골재를 콘크리트용으로 널리 이용하지 못하는 실정이다. 특히, 높은 흡수율과 마모율을 가진 재생골재의 함수상태와 양생조건이 콘크리트의 압축 강도에 어떤 영향을 미치는지에 대한 평가가 필요하다. 따라서, 본 연구에서는 재생 굵은 골재의 함수상태와 양생조건을 변수로 하여 실험을 통하여 압축 강도에 대한 영향을 알아보고, 천연 굵은 골재 콘크리트의 압축 강도 특성과 비교하고자 하였다. 본 실험연구 결과 재생 굵은 골재를 사용한 콘크리트의 양생조건에 따른 압축 강도 영향은 천연골재 콘크리트와 비슷하였으며, 압축 강도는 약 13~17 % 낮게 나타났다. 재생 굵은 골재의 함수상태에 따른 영향은 습윤양생의 경우 습윤상태의 골재를 사용한 콘크리트가 건조상태의 골재를 사용한 콘크리트 보다 조금 높은 압축 강도를 보였으나, 대기양생의 경우는 이와 반대로 건조상태의 재생골재 콘크리트가 습윤상태의 콘크리트보다 상대적으로 높게 나타났다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
• /
• pp.184-191
• /
• 1996

In curing Process of tire, Contact and slip occurs between green tire and curing bladder. The curing process is a critical step in the manufacture of tires. In this investigation, curing bladder shaping is examined using a finite element method. Specifically, a finite element model between the inner part of green tire and the outer part of curing bladder is generated using contact element and curing bladder is generated using incompressible element, The experimental tensile tests are used to get the material properties of bladder rubber on practical conditions. Numerical analyses are performed on two different bladder types, different overall outer diameters of curing bladder and different heights of curing bladder.

• 한국건축시공학회지
• /
• 제2권4호
• /
• pp.163-168
• /
• 2002

The object of this study is to define the characteristics of high performance concrete with varing compressive strength of concrete and curing temperature. The major test variables are 1) high strength concrete(500kg/$cm^2$) and ordinary strength concrete(240kg/$cm^2$) compressive strength, 2) curing temperature and condition, 3) concrete curing age, 4) three types of cement. From the test results were shown that curing temperature and curing conditions were also very effective for high strength concrete and ordinary strength concrete, and concrete were largely effected by cement type and temperature during the hydration reaction process. This paper describes the effect of curing temperature for strength and characteristics of high performance concrete.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.463-471
• /
• 2009

Cemented soils or concrete are usually cured under moisture conditions and their strength increases with curing time. An insufficient supply of water to cemented soils can contribute to hydration process during curing, which results in the variation of bonding strength of cemented soils. In this study, by the consideration of in situ water supply conditions, cemented sand with cement ratio less than 20% was prepared by air dry, wrapped, and underwater conditions. A series of unconfined compression tests were carried out to evaluate the effect of curing conditions on the strength of cemented soils. The strength of air dry curing specimen was higher than those of wrapped cured specimen when cement ratio was less than 10%, whereas it was lower when cement ratio was greater than 10%. Regardless of cement ratio, air dry cured specimens were stronger than underwater cured specimens. A strength increase ratio with cement ratio was calculated based on the strength of 4% cemented specimen. The strength increase ratio of air dry cured specimen was lowest and that of wrapped and underwater cured ones increased by square. Strength of air dry cured specimen dropped to maximum 30% after wetting when cement ratio was low. However, regardless of cement ratio, strength of wrapped specimens dropped to an average 10% after wetting.

• The Journal of Advanced Prosthodontics
• /
• 제13권2호
• /
• pp.71-78
• /
• 2021

Purpose. This study aims to compare the volumetric change, degree of conversion (DOC), and cytotoxicity of 3D-printed restorations post-cured under three different conditions. Materials and Methods. 3D-printed interim restorations were post-cured under three different conditions and systems: 5 min, 30 min, and 24 h. Three-unit and six-unit fixed dental prostheses (n = 30 for each case) were printed; ten specimens from each group were post-cured and then scanned to compare their volumetric changes. Root-mean-squared (RMS) values of the data were acquired by superimposing the scanned files with original files. Thirty disk-shaped specimens were printed to evaluate the DOC ratio. Fourier transform infrared spectroscopy was used to compare the DOCs of 10 specimens from each group. Human gingival fibroblasts were used to measure the cell viability of every specimen (n = 7). The data from this experiment were employed for one-way analysis of variance and Tukey's post-hoc comparisons. Results. Differences between the three-unit restorations were statistically insignificant, regardless of the post-curing conditions. However, for the six-unit restorations, a high RMS value was acquired when the post-curing duration was 30 min. The average DOC was approximately 56 - 62%; the difference between each group was statistically insignificant. All the groups exhibited cell viability greater than 70%, rendering them clinically acceptable. Conclusion. The post-curing conditions influenced the volume when the length of the restoration was increased. However, this deviation was found to be clinically acceptable. Additionally, post-curing did not significantly influence the DOC and cytotoxicity of the restorations.