• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.73-76
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• 2003

Phase transformation of Bi-2223 tape during the final heat treatment has been investigated through the various duration time of heat treatment in a specially designed 3-step heat treatment. It was found that the phase assemblage in the sintering was determined by the sintering time and temperature. In this study, sintering time was changed to optimize the Bi-2223 phase assemblage, and acquire high critical current density. High critical current samples with Ic = 85 A and Je = 8.9 kA/$cm^2$ have been measured at 77K and self-field for 55-filament tapes sintered by optimum condition.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.221-223
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• 1999

In this work, samples were manufactured variously by changing conventional calcining and sintering conditions and we tried the utilization by making the heat treatment time, which is demanded to high-Tc phase formation, much shorter. We found out optimal heat treatment conditions with the analysis on formation process at superconducting phase in term of the change of calcining and sintering time and then, examined X-ray diffraction(XRD) patterns, scanning electron microscope(SEM) measurement and energy dispersive X-ray spectrometer(EDX) of the samples manufactured under heat treatment conditions which we suggest here. As a result, 2223 high-$T_c$, phase of (Bi,Pb)SrCaCuO superconductor starting with ($Bi_l$ xPbx,)$_2$$Sr_2$$Ca_2$$Cu_3$$O_y$, composition was formed from 1 hr sintering sample at temperature nearby melting point and also the completed sample with calcining and sintering time of 9 hr was formed high-$T_c$.low-$T_c$ phase appearing in sight above the critical temperature of liquid $N_2$.

• 동력기계공학회지
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• 제17권4호
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• pp.72-78
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• 2013

Compacted graphite iron 340 was carried out the heat treatment from 873 to 1,273 K. Compacted graphite iron 340 was evaluated relationship between the sound velocity, the attenuation coefficient and the tensile strength. The obtained results are as following. The signal strength of C scan images were weak according to increasing of heat treatment temperature and time. The amplitude of A scan and B scan was also low. This can be cause that the graphite was grown into the type of vermicular, and the many of grain boundary with ultrasound scattering were increase. The sound velocity was depend upon the heat treatment temperature and time, the attenuation coefficient had nothing to do with the temperature and time. The higher the heat treatment temperature, the tensile strength and the sound velocity were decreased. However, the tensile strength was proportional to the sound velocity. The higher tensile strength, the faster the sound velocity.

• Journal of the Korean Wood Science and Technology
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• 제36권6호
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• pp.41-48
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• 2008

본 연구에서는 소나무 원목의 열처리 시 소요에너지에 대해 분석하였다. 소나무재선충 감염목에 대한 적절한 열처리는 소나무 재선충의 감염 확산을 막고, 감염목의 용재로서의 사용 가능성을 높인다. 본 연구에서는 병해충 감염목의 FAO 열처리 기준(International standards for phytosanitary measures (ISPM) No.15)에서 제시한 병해충 사멸 조건인 '목재 중심부 온도를 $56^{\circ}C$에서 30분 유지'를 위하여 소요되는 에너지를 평가하였다. 열처리에 소요되는 총 소요에너지는 초기 열처리 설정조건 도달에 필요한 처리기 벽체 가열, 처리기 내 공기 가열, 목재가열, 습도유지, 벽체 열손실로 구성되는 초기소요에너지와 열처리 설정조건 도달 이후의 열손실 보완 소요에너지, 즉 목재가열, 습도유지 및 처리기 벽체 열손실을 보완하기 위한 열손실 보완 에너지로 구분하였다. 단위시간당 초기소요에너지는 열처리 설정조건 도달 이후의 단위시간당 열손실 보완 에너지량보다 크며, 설정조건도달 이후의 단위시간 당 소요에너지는 거의 일정한 값을 가졌다. 시험결과 실험조건에 있어서 건조 온도와 더불어 상대습도가 매우 큰 영향을 미쳤으며 목재조건으로는 함수율 차이에 의해 변하는 밀도가 큰 영향을 미쳤다. 고온과 높은 상대습도 및 낮은 함수율, 즉 낮은 밀도가 열처리 속도를 증가시켰다. 이 연구를 통하여 소나무재의 열처리에 있어서 보다 효율적인 에너지 관리 방안을 마련할 수 있을 것으로 기대된다.

• 한국주조공학회지
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• 제29권1호
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• pp.45-51
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• 2009

Conventionally, Al-Sn bearing manufacturing involves casting the Al-Sn alloy and roll-bonding to a steel backing strip. This article will describe the microstructural control of Al-Sn metal bearing alloy following heat treatment. When the pure aluminum rod dipped in the melt of tin maintained below the melting point of aluminum, the melting of aluminum was accelerated with penetration of tin along the grain boundary of aluminum. The length of plate-shaped eutectic tin was decreased with heat treatment time. With even longer heat treatment time over 1 hour the length of eutectic tin didn't decrease any more, while resulting in coarsening of aluminum matrix. Exuded liquid of eutectic tin was formed at the surface of Al-Sn alloy after heat treatment even at below eutectic temperature.

• Journal of Dairy Science and Biotechnology
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• 제34권4호
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• pp.271-278
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• 2016

The main purpose of milk heat-treatment is to improve milk safety for consumer by destroying foodborne pathogens. Secondly, heat-treatment of milk is to increase maintaining milk quality by inactivating spoilage microorganisms and enzymes. Pasteurization is defined by the International Dairy Federation (IDF, 1986) as a process applied with the aim of avoiding public health hazards arising from pathogens associated with milk, by heat treatment which is consistent with minimal chemical, physical and organoleptic changes in the product. Milk pasteurization were adjusted to $63{\sim}65^{\circ}C$ for 30 minutes (Low temperature long time, LTLT) or $72{\sim}75^{\circ}C$ for 15 seconds (High temperature short time, HTST) to inactivate the pathogens such as Mycobacterium bovis, the organism responsible for tuberculosis. Ultra-high temperature processing (UHT) sterilizes food by heating it above $135^{\circ}C$ ($275^{\circ}F$) - the temperature required to destroy the all microorganisms and spores in milk - for few seconds. The first LTLT system (batch pasteurization) was introduced in Germany in 1895 and in the USA in 1907. Then, HTST continuous processes were developed between 1920 and 1927. UHT milk was first developed in the 1960s and became generally available for consumption in the 1970s. At present, UHT is most commonly used in milk production.

• Corrosion Science and Technology
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• 제21권6호
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• pp.495-502
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• 2022

Anodization is a representative electrochemical surface treatment method that can improve both heat resistance and corrosion resistance by forming an anodization film on the surface of the aluminum. However, these properties can be changed after an additional heat treatment process. In this study, Al 6061 was subjected to an anodization process at 60 V for 1 hour, 5 hours, or 9 hours. An additional heat treatment process was performed at 500 ℃ for 30 minutes. Field emission scanning electron microscopy (FE-SEM) analysis revealed that the thickness of the anodized film was increased in proportion to the anodization time. Both pore size and pore diameter of the anodized film was also increased after anodization. After an additional heat treatment process, there were no significant changes in the thickness, pore size, or pore diameter of the anodized film. Heat resistance was confirmed through thermal analysis and chemical resistance was evaluated with a potentiodynamic polarization test.

• Journal of the Korean Wood Science and Technology
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• 제51권6호
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• pp.447-447
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• 2023

This study aimed to convert underutilized moso bamboo into high-value added products such as fences, interior materials, lighting fixtures, and accessories. Green moso bamboo poles with a diameter of approximately 10 cm and a length of approximately 3.7 m were heat treated at 140℃ using a large-scale kiln. The processing time was meticulously adjusted through various stages, including pretreatment (6-8 hours at 60℃), cooking (8-10 hours at 100℃), steaming (26-30 hours at 120℃), heating (4-6 hours at 140℃), and finally, cooling (below 80℃). A meticulously designed heat treatment process has enabled efficient mass production of moso bamboo poles with improved qualities, including minimal splitting, moisture levels below 3%, and a specific gravity of 1.05. The focus of this study was to present the physical and drying properties, such as color, dimensional change, specific gravity, moisture content, and splitting, observed during the heat treatment process.

• 열처리공학회지
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• 제31권3호
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• pp.104-110
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• 2018

The effects of heat treatment time and cooling method on microstructure and mechanical property of Cu-22wt%Sn alloy were discussed. ${\alpha}+{\delta}$ mixed phase structure was obtained in air-cooled specimens after heat treatment at 775, 750, and $700^{\circ}C$ for 1 hour. On the other hand, in water-cooled specimens, ${\alpha}+{\beta}^{\prime}$ martensite mixed phase was obtained. In the case of water-cooled specimens, the hardness value decreased with decreasing heat treatment temperature because the volume fraction of ${\alpha}$ phase with low hardness value increased as the heat treatment temperature decreased. In water-cooled specimen after heat treatment at $600^{\circ}C$, ${\gamma}^{\prime}$ martensite was formed instead of ${\beta}^{\prime}$ martensite. The hardness value of ${\gamma}^{\prime}$ martensite was lower than those of ${\beta}^{\prime}$ and ${\delta}$ phases.

• Journal of the Korean Wood Science and Technology
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• 제46권3호
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• pp.285-296
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• 2018

ISPM No. 15에 의거한 열처리 목재의 검증을 위한 연구로서 열처리 목재 표면의 분광학적 특성을 분석하였다. IR 스펙트럼 상에서는 다양한 작용기들이 확인되지만 수종간, 열처리 시간 및 보관 기간에 따른 특별한 차이를 발견하기 어려웠다. HBI(hydrogen-bonding intensity)는 보관 기간에 따른 열처리 목재의 변화는 관찰할 수 있지만 열처리 시간에 따른 변화는 관찰하기 어려웠다. 하지만 PCA score plot 상에서 수종 내에서 60분 혹은 90분의 열처리 시간에 따라 목재의 분류가 가능하였다. PCA에서 열처리 목재의 분류의 기준은 목재 내 리그닌의 방향족 환과 셀룰로오스의 C-H bending이었으며 이들 성분에 의해 ISPM No. 15로 열처리된 목재를 분류할 수 있었다.