• Journal of the Korean Wood Science and Technology
• /
• 제43권4호
• /
• pp.438-445
• /
• 2015

유럽에서 개발된 여러 가지 열개질처리 방법 중 독일의 오일열처리 방법을 적용하여 국산 잣나무 시편을 $180^{\circ}C$와 $200^{\circ}C$에서 열처리하였다. 또 같은 종류의 잣나무 시편을 $200^{\circ}C$에서 Thermowood열처리하였다. 열처리 시편의 표면을 자동대패로 대패한 후 1 mm와 4 mm 깊이의 재색을 색차계로 측정하였다. 열처리 시편 내층의 평균 백색도(L*)는 Oil-180 시편이 가장 높고, Oil-200 시편, Tmo-200 시편 순이다. 열처리에 의해 평균 적색도는 모든 시편이 증가하였으나 평균 황색도는 열처리 조건에 따라 증가하거나, 감소하였다. 무처리와 비교한 평균 색차값(${\Delta}E*$)은 Oil-200 시편과 Tmo-200 시편이 30.0 이상이나, Oil-180 시편은 18.4로 상대적으로 적게 변하였다. 열처리 시편 내층간의 평균 색차값 (${\Delta}E*$)은 6.0 이하로 세 열처리 조건 모두 시편 내층의 재색을 균일하게 변화시켰다고 할 수 있다.

• Journal of the Korean Wood Science and Technology
• /
• 제40권5호
• /
• pp.343-351
• /
• 2012

A large diameter roundwood is an important element of Korean traditional buildings, Hanok, and is hard to be dried without surface cracks. Four different pretreatments, such as pre-cracking, oil heating, kerfing-oil heating and PEG impregnation, were investigated for reducing the surface cracks of large-diameter roundwood specimens during heat treatment. The roundwood specimens of pre-cracking, oil heating and kerfing-oil heating showed surface cracks during pretreatment, but that of PEG impregnation did not. It was confirmed that kerfing reduced the total crack width. Among the four pretreatments and control only the PEG impregnation roundwood specimen had no crack on both outer and inner surfaces after heat treatment. The PEG impregnation specimen shrank only 1.6% in the tangential direction while the pre-cracking did 8.0%.

• 한국염색가공학회지
• /
• 제24권3호
• /
• pp.173-179
• /
• 2012

Silk fabric treated with fluorocarbon resins (Asahi Guard AG-7005 and AG-E061) were washed and subsequently heat treated varying the washing cycles and the temperature. After the processing, the water and oil repellencies, and contact angle to water were evaluated. The water and oil repellencies decreased by the washing and recovered by following heat treatment. Also ESCA measurement was carried out to investigate the surface chemical composition of the treated fiber. The $F_1s$ intensity of the treated fabric decreased by the washing and recovered by the subsequent heat treatment. On the other hand, the $O_1s$ intensity increased by the washing and decreased by following heat treatment. From the results, it is clear that change of the water and oil repellencies of the silk fabric treated with fluorocarbon resin occurred by the washing and subsequent heat treatment. Considering a change of the water repellency of the silk fabric treated with fluorocarbon resin, it seems likely that the fluoroalkyl group of the fluorocarbon resin rotates from surface to inside of the fiber by the washing to adapt to the hydrophilic circumstance, and the orientation of the fluoroalkyl groups of the resin disturbed by the washing recovers the orientation to the fiber surface after the subsequent heat treatment.

• 기술사
• /
• 제31권5호
• /
• pp.110-120
• /
• 1998

The effect of heat treatment and the order of antioxidants treatment toward the thermally oxidized palm oil which has been stored at 60 $^{\circ}C$ was studied. The summerized results of this study are as follows; 1. In the accelerated autoxidation condition, tocopherol showed no distinct effect on the changes of peroxide of value between added tocopherol samples pre-and post treatment by heating. But, rosemary extract showed opposite result. It was supposed that rosemary extract had lower thermostability then tocopherol, because rosemary extract lost it's antioxidative activity during heating process. 2. The changes of acid value and anisidine value were more affected by heat treatment than the order of antioxidant treatment. 3. The oxidative stability measured by OSI showed same tendency as peroxide value. That is, the antioxidative activity of tocopherol in palm oil was more dependent on addition of antioxidants than heat treatment, but the rosemary extract had opposite character for antioxidative action in palm oil.

• 열처리공학회지
• /
• 제28권1호
• /
• pp.24-31
• /
• 2015

In this study, a simulation was used to derive an optimal process of heat treatment with carburizing, and compared the derived result with SCr420HB helical gear in heat treatment with carburized quenching process about a change of the quenching method. The optimal carburizing process time is derived by the simulation with the theoretical time. The process has been performed by oil quenching and salt quenching method. Through the comparison of the results from the simulation(Hardness, effective case depth hardened by carburizing treatment and deformation) and the actual process, analyzed the error value of each quenching. And it verified the applicability of the simulation.

• 열처리공학회지
• /
• 제18권1호
• /
• pp.41-45
• /
• 2005

• Corrosion Science and Technology
• /
• 제13권1호
• /
• pp.28-35
• /
• 2014

Recently, the fuel oil of diesel engines of marine ships has been increasingly changed to heavy oil of low quality as the oil price is getting higher and higher. Therefore, the spiral gear attached at the motor of the oil purifier which plays an important role to purify the heavy oil is also easy to expose at severe environmental condition due to the purification of the heavy oil in higher temperature. Thus, the material of the spiral gear requires a better mechanical strength, wear and corrosion resistance. In this study, the heat treatment(tempering) with various holding time at temperature of $500^{\circ}C$ was carried out to the alloy of Cu-7Al-2.5Si as centrifugal casting, and the properties of both hardness and corrosion resistance with and without heat treatment were investigated with observation of the microstructure and with electrochemical methods, such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram, and a.c. impedance. in natural seawater solution. The ${\alpha}$, ${\beta}^{\prime}$ and ${\gamma}_2$ phases were observed in the material in spite of no heat treatment due to quenching effect of a spin mold. However, their phases, that is, ${\beta}^{\prime}$ and ${\gamma}_2$ phases decreased gradually with increasing the holding time at a constant temperature of $500^{\circ}C$. The hardness more or less decreased with heat treatment, however its corrosion resistance was improved with the heat treatment. Furthermore, the longer holding time, the better corrosion resistance. In addition, when the holding time was 48hrs, its corrosion current density showed the lowest value. The pattern of corroded surface was nearly similar to that of the pitting corrosion, and this morphology was greatly observed in the case of no heat treatment. It is considered that ${\gamma}_2$ phase at the grain boundary was corroded preferentially as an anode. However, the pattern of general corrosion exhibited increasingly due to decreasing the ${\gamma}_2$ phase with heat treatment. Consequently, it is suggested that the corrosion resistance of Cu-7Al-2.5Si alloy can be improved with the heat treatment as a holding time for 48 hrs at $500^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 추계학술대회 논문집
• /
• pp.225-228
• /
• 1997

The main fault in this interface is that power cable insulating materials are mainly composed of a double layered structure, XLPE/FPDM laminates in cable joint. In this parer, we instituted the interface of XLPE/EPDM laminates and then investigated the breakdown and conduction characteristics as a function of heat treatment time. The results showed that conduction current was influenced by volatile crosslinking by-products which remained inside the insulating material during the production of XLPE and EPDM, especially during heat treatment process. And conduction current of XLPE/Oil 12500cSt/EPDM was more stable than XLPE/Grease/EPDM from the long heat treatment time. AC breakdown strength of silicone oil itself from the heat treatment was changed during the 4∼12 hour heat treatment time.

• 한국식품영양과학회지
• /
• 제46권10호
• /
• pp.1265-1269
• /
• 2017

본 연구에서는 신선 농산물의 미생물학적 안전성을 제고하기 위해 항균 효과가 있는 clove bud essential oil(CBEO)과 mild heat(MH) 처리를 병합 처리하여 Escherichia coli O157:H7이 접종된 red oak leaf의 미생물 수 변화를 측정하였다. 0.2% CBEO와 $50^{\circ}C$ MH 병합 처리구는 단순 물세척 처리구보다 1.45 log CFU/g 더 낮은 미생물 수를 나타내어 모든 병합 조건 중 가장 높은 미생물 제어 효과를 보였다. 또한, 본 병합 처리구는 비 세척 처리구와 비교하여 9일간의 저장 기간 동안 1.67~2.25 log CFU/g 더 낮은 미생물 수를 나타내어 미생물 제어 효과가 지속됨을 확인하였다. 따라서 이러한 결과들로부터 CBEO와 MH의 병합 세척 처리는 저장 중 red oak leaf와 같은 신선 농산물의 미생물학적 안전성을 확보하는 데 효과적으로 사용될 수 있다고 판단된다.

• 열처리공학회지
• /
• 제35권6호
• /
• pp.337-342
• /
• 2022

In metal cutting, water-soluble cutting oil is used for cooling the surface of the workpiece and improving the surface roughness. However, waste cutting oil contains preservatives and surfactants, and if it is discarded as it is, it has an great influence on environmental pollution. For this reason, regulations on the use of cutting oil are being stricter. Hence, the development of eco-friendly treatment technologies is required. In this study, a diamond electrode doped with boron on a niobium substrate was deposited by thermal filament chemical vapor deposition and waste cutting oil was treated using an electrochemical method. Compared to the total amount of organic carbon contained in the waste cutting oil, it was confirmed that the boron-doped diamonds developed from this study showed much better performance than electrodes that has been widely used before.