• 한국표면공학회지
• /
• 제24권2호
• /
• pp.103-113
• /
• 1991

Electroless Ni-Cu-P alloy plating of Al base hard disk was performed to investigate some properties according to the change of composition. It was found that the composition of Ni and Cu in deposits changed linearly with increasing the mole ratio of NiSO4.6H2O/CuSO4.5H2O. The increase in hardness by heat - treatment was confirmed to be associated with small size grained crystallization of the amorphous deposits. Acid resistance of all deposits layer. which had been heated up to 30$0^{\circ}C$, was found to be exellent when immersed in 1N-H2SO4 solution, and it showed more superior acid resistance with decreasing Cu content and with increasing P. The resistivity of the deposits heat treated became smaller at temperature more than 50$0^{\circ}C$, and it became largerly with increasing P content. Cu 44.1wt% alloy(C bath) showed the most superior non-magnetically stable characteristics after heat treatment. It was superiorly with higher temperature and with decreasing P content.

• 폴리머
• /
• 제29권1호
• /
• pp.91-95
• /
• 2005

화학적 가교와 방사선 가교에 의해 내열특성을 가진 PVA 수화젤을 제조하였다. 제조된 수화젤의 젤화율, 팽윤도와 젤강도 같은 기계적 특성을 측정하였다. 젤화율은 화학적 가교 반응시간과 방사선 조사선량이 증가할수록 증가하였고, 화학적 가교 후에 방사선 가교를 했을 경우에 화학적 가교만 했을 때보다 높은 값을 보였다. 젤강도는 화학적 가교 반응시간이 증가할수록 증가하였고, 방사선 조사선량이 감소할수록 증가하였다. 5시간 화학적 가교만 한수화젤과 화학적 가교 후에 방사선 가교를 한 수화젤이 고온에서의 내열특성이 우수하였다.

• 한국식품과학회지
• /
• 제51권5호
• /
• pp.452-458
• /
• 2019

The objective of this study was to investigate the physicochemical characteristics and antioxidant potential of garlic processed using different heat treatments conditions, which is an effective method for removing the unpleasant odor and taste of raw garlic. The pH and soluble solid content of raw garlic (pH 6.07, $7.7^{\circ}Bx$) were almost equal or slightly higher than that of processed garlic samples (pH 5.06-6.09, $7.1-7.4^{\circ}Bx$). The color of processed garlic was also significantly affected. The amounts of amino acids such as ${\gamma}$-amino-n-butyric acid and few essential amino acids also increased after the thermal treatment of garlic. The antioxidant potentials of red and black garlic were higher than that of raw garlic. The polyphenol content of processed garlic ($38.51-81.51{\mu}g$ gallic acid equivalent/g sample) was significantly higher than that of raw garlic ($30.66{\mu}g$ gallic acid equivalent/g sample). These results indicated that heat treatment for different durations under a controlled environment enhanced the nutritional and functional properties of garlic.

• 열처리공학회지
• /
• 제35권2호
• /
• pp.88-95
• /
• 2022

Titanium alloy for bio-medical applications have been developed to reduce the toxicity of alloying elements and avoid the stress-shielding effect which is caused by relatively high elastic modulus compared to bone. Ti-39Nb-6Zr (TNZ40) alloy of elastic modulus exhibits around 40 GPa in the case of beta single phase. However, the strength of this alloy is lower than the other types of titanium alloys. Many research found that adding oxygen to beta-titanium alloys is beneficial for improving the strength through solid solution strengthening. In this study, TNZ40 ingots with addition of O were prepared by an arc remelting process (Ti-39Nb-6Zr-0.16O (wt.%), Ti-39Nb-6Zr-0.26O (wt.%)). Thermo-mechanical processing (i.e., heat treatment, cold swaging and aging heat treatment) has been performed under various conditions. Therefore, the aim of this study is to investigate the effect of oxygen content and ω phase formation on microstructure and mechanical properties.

• 생명과학회지
• /
• 제12권5호
• /
• pp.589-594
• /
• 2002

당근의 열처리 조건에 따른 휘발성 terpenoids 함량의 변화를 조사하였는데, 열처리 온도가 높을수록 휘발성 terpenoids가 많이 감소하였으며, 열처리 시간에 따른 휘발성 terpenoids는 $\alpha$-pinene 및 total terpenoids의 경우 최초 30분 동안 급속히 감속하였으며, 그 후 시간이 지남에 따라 감소율이 낮아지는 경향을 보였다 당근주스의 살균 온도별, 시간별 휘발성 terpenoids의 변화를 조사한 결과, 살균온도가 높을수록 휘발성 terpenoids 함량이 빠른 속도로 감소함을 보여주고 있으며, 살균시간에 따른 휘발성 terpenoids의 함량은 최초 20분간 급속히 감소하다가 이후에는 완만하게 감소하였다. Total terpenoids의 경우 10$0^{\circ}C$에서 20분간 살균했을 시 6$0^{\circ}C$ 및 8$0^{\circ}C$에서 60분간 살균했을 시 보다 더 많이 감소하였는데, 당근주스의 휘발성terpenoids 함량을 줄이기 위해서는 고온단시간 살균이 저온장시간 살균보다 더 유리하다는 것을 알 수 있었다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
• /
• pp.209-214
• /
• 1994

The heat of hydration of cement causes the intemal temperature rise at early age, particulay in massive concrete structures. As the results of the temperature rise and restraint condition, the thermal stress amy induce cracks in concrete. The prediction of the thermal stress is very important in design and consturction slages in order to control the cracks in mass concrete. In this study, the temperature rise of high strength concrete due to the heat of hydration is investigated. Test variables are type and content of binder. As the results, the temperature rise is imcreased with increasing cement content. However, the increament is decreased in higher cement comtnet range. Fly ash is effictive in the reduction of hydration heat.

• 신재생에너지
• /
• 제3권4호
• /
• pp.38-46
• /
• 2007

In order to characterize the thermal conductivity and viscosity of grout materials used for backfilling ground heat exchangers, nine bentonite grouts and cement grouts being adapted in the United State have been considered in this study. The bentonite grouts indicate that the thermal conductivity and viscosity increase with the content of bentonite or filler (silica sand). In addition, material segregation can be observed when the viscosity of grout is relatively low. The saturated cement grouts appear to possess much higher thermal conductivity than the saturated bentonite grouts, and the reduction of thermal conductivity in the cement grouts after drying specimens is less than the case of the bentonite grouts. Maintaining the moisture content of grouts is a crucial factor in enhancing the efficiency of ground heat exchangers.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.529-532
• /
• 2007

In order to characterize the thermal conductivity and viscosity of grout materials used for backfilling ground heat exchangers, nine bentonite grouts and cement grouts being adapted in the United State have been considered in this study. The bentonite grouts indicate that the thermal conductivity and viscosity increase with the content of bentonite or filler (silica sand). In addition, material segregation can be observed when the viscosity of grout is relatively low. The saturated cement grouts appear to possess much higher thermal conductivity than the saturated bentonite grouts, and the reduction of thermal conductivity in the cement grouts after drying specimens is less than in case of the bentonite grouts. Maintaining the moisture content of grouts is a crucial factor in enhancing the efficiency of ground heat exchangers.

• Computers and Concrete
• /
• 제6권1호
• /
• pp.19-40
• /
• 2009

This paper describes the development of modified heat of hydration and maturity-strength models for concrete containing fly ash and slag. The modified models are developed based on laboratory and literature test results, which include different types of cement, fly ash, and slag. The new models consider cement type, water-to-cementitious material ratio (w/cm), mineral admixture, air content, and curing conditions. The results show that the modified models well predict heat evolution and compressive strength development of concrete made with different cementitious materials. Using the newly developed models, the sensitivity analysis was also performed to study the effect of each parameter on the hydration and strength development. The results illustrate that comparing with other parameters studied, w/cm, air content, fly ash, and slag replacement level have more significantly influence on concrete strength at both early and later age.

• 한국식품과학회지
• /
• 제30권6호
• /
• pp.1327-1332
• /
• 1998

The optimum thermal condition of retort Biji product was determined by heat penetration curve, aerobic bacteria count and sensory test. Retort Biji showed a simple logarithmic heating curve regardless of solid content. Heating time was a $26{\sim}27$ min until Fo value reached 9 min and the amount of microorganism in the Biji product sterilized for 26 min at $121^{\circ}C$ were decreased to $10^{-4}\;CFU/g$, indicating the safe range for retort product. The rate of heat penetration was reduced as solid content and size of product were increased, whereas sterilization temperature and initial temperature of product influenced the heat penetration curve. Sensory scare indicated that there was no significant difference in color, flavor, and appearance among different thermal processes. However, Biji product sterilized at $121^{\circ}C$ showed the highest score in overall preference value.