• 열처리공학회지
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• 제25권4호
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• pp.190-195
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• 2012

This study aims to investigate and compare the microstructures and room temperature tensile properties for AZ91 and ECO-AZ91 (AZ91+0.3%CaO) alloys in as-cast, T4 and T6 states, respectively. In as-cast state, the ECO-AZ91 alloy has finer microstructure than the AZ91 alloy. The AZ91 alloy exhibits greater ductility, while YS and UTS are inferior to those of the ECO-AZ91 alloy. After T4 treatment, most of ${\beta}$ compounds disappear in the AZ91 alloy, whereas ${\beta}$ phase is still observed in the ECO-AZ91 alloy due to its enhanced thermal stability, resulting in lower values of ductility and UTS. In T6 state, YS and UTS are better in the ECO-AZ91 alloy.

• Asian-Australasian Journal of Animal Sciences
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• 제33권4호
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• pp.634-639
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• 2020

Objective: This study was conducted to investigate the effect of heating of foot-and-mouth disease (FMD) vaccine before injection, on the incidence of lesions at the injection site (pork butt), amount of discarded meat, and economical benefit. Methods: In total, 101,086 piglets raised in 30 farms, were vaccinated in the neck with 2 mL of FMD vaccine at 56 d and 84 d of age using a commercial syringe. The heat treatment group (48,511 pigs) was injected with the FMD vaccine after it had been heated in a water bath at 40℃ for 20 min. After slaughter, the incidence of lesions on the pork butt was inspected, and the subsequent amount of discarded meat was recorded. Results: Heat treatment of FMD vaccine reduced the incident rate of lesions on the pork butt (p<0.01). Overall, 17.81% of the pigs in the heat treatment group had lesions, while the incident rate in the control group was 21.70%. The amount of discarded meat per head of total pigs and per head of pigs with lesions were significantly lower in the heat treatment group than the control group (p<0.01). Thus, the proportion of discarded meat to dressed carcass was lower in the heat treatment group (0.249%) compared with the control group (0.338%) (p<0.01). Farms that rear 1,000 sows can gain 1,863,289 KRW (1,600 USD) in one year when they adopt heat treatment of FMD vaccine before injection. Conclusion: Heat treatment of FMD vaccine using simple heat equipment (water bath) can be effective in reducing lesions caused by FMD vaccination and increase the economic benefits in pig farms.

• The Journal of Advanced Prosthodontics
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• 제8권2호
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• pp.75-84
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• 2016

PURPOSE. To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS. 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with $60^{\circ}C$ heat-treatment), and G4 (silane alonethen dried with $100^{\circ}C$ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in $N/mm^2$). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin-ceramic interface. RESULTS. SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (P<.001). FIN ceramics had the highest rate of cohesive failure on the ceramic surfaces than other ceramic groups. AFM images showed that the surface treatment groups exhibited similar topographies, except the group treated with HF. CONCLUSION. The heat treatment was not sufficient to achieve high SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments.

• Corrosion Science and Technology
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• 제23권4호
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• pp.283-288
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• 2024

Hot-dip Zn-Mg-Al coatings have a complex microstructure consisting of Zn, Al, and MgZn₂ phases. Its crystal structure depends on alloy content and cooling rates. Microstructure and corrosion resistance of these coatings might be affected by heat treatment. To investigate effect of heat treatment on microstructure and corrosion resistance of Zn-Mg-Al coatings, Zn-1.5%Mg-1.5%Al coated steel was heated up to 550 ℃ at a heating rate of 80 ℃/s and cooled down to room temperature. At above 500 ℃, the ternary phase of Zn-MgZn₂-Al was melted down. Only Zn and MgZn₂ phases remained in the coating. Heat- and non-heat-treated specimens showed similar corrosion resistance in Salt Spray Test (SST). When a Zn-3.0%Mg-2.5%Al coated steel was subjected to heat treatment at 100 ℃ or 300 ℃ for 200 h and compared with GA and GI coated steels, the microstructure of coatings was not significantly changed at 100 ℃. However, at 300 ℃, most Al in the coating reacted with Fe in the substrate, forming a Fe-Al compound layer in the lower part of the coating. MgZn₂ was preferentially formed in the upper part of the coating. As a result of SST, Zn-Mg-Al coated steels showed excellent corrosion resistance, better than GA and GI.

• 셀메드
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• 제12권4호
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• pp.16.1-16.2
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• 2022

Treatment of patients with pain is directed at relieving pain and restoring function. Heat therapy has been used as a pain treatment. The mean temperatures were 40 and 41℃. Our device, Dr.Pakk heats special silicone to 41℃ with far-infrared rays and attaches it to the painful knee using a vacuum to show the effect. The core technology of the Dr.Pakk is that deep heat is generated when the heat is transmitted deeply by attaching it to the skin. In our experience, Dr.Pakk can be especially effective for knee pain.

• Journal of Advanced Marine Engineering and Technology
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• 제24권6호
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• pp.70-77
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• 2000

In this paper, the effect of solution and age heat treatment to the corrosion behavior for the Ti-6Al-4V alloy were studied by cyclic polarization methods. Ti-6Al-4V was solution heat treated at $1,066^{\circ}C$ and $966^{\circ}C$ for 5 hours, and followed by age heat treated at $650^{\circ}C$, $600^{\circ}C$ and $550^{\circ}C$ with 1, 2, 4, 8 and 16 hours under vacuum environment. Test solution was 3.5% NaCl with temperature $25^{\circ}C$. The obtained results were as follows: 1. Base metal was exhibited higher electrical charge than that of solution and aged material. With decrease of solution-treatment temperature from 1066 to $966^{\circ}C$, the electrical charge was increased due to softening of micro structure. 2. The corrosion resistance of specimen that solution treated at $966^{\circ}C$ for 5 hours and age heat treated at 650, 660 and $550^{\circ}C$ were increased with increase of aging time to 4, 8 and 16 hours respectively, and then decreased. 3. In case of 316L stainless steel, measured charge and corrosion potential was 0.0627 coulomb and -614 mV respectively. Corrosion resistance of Ti-6Al-4V was higher than that of 316L.

• 한국산림과학회지
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• 제61권1호
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• pp.45-52
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• 1983

본(本) 연구(硏究)는 우리나라 주요(主要) 장기조림수종(長期造林樹種)에 포함(包含)되어 있는 잣나무의 펄프자원화(資源化)를 위한 일환(一環)으로, 크리프트펄프화시(化時) 발생(發生)될 수 있는 pitch trouble을 감소(減少)시키기 위하여, 칩을 온도별(温度別)(40, 50, $60^{\circ}C$) 및 시간별(時間別)(1, 3, 5, 7일(日))로 열처리(熱處理)를 실시(實施)하고, 그에 따른 수지함량(樹脂含量)과 종이의 물리적(物理的) 성질(性質)을 조사(調査)하기 위하여 수행(修行)되었다. 본(本) 연구(硏究) 결과(結果)로 $40^{\circ}C$로 열처리(熱處理)한 것이 인공조림목(人工造林木) 및 천연림목(天然林木)에 대(對)하여 모두 수율(收率) 및 수지함량(樹脂含量)에 있어서 가장 좋은 결과(結果)를 보였으나, 다른 성질(性質)은 거의 개선(改善)되지 않거나, 또는 오히려 악화되는 결과(結果)를 초래(招來)하였다. 종이의 강도적(強度的) 성질(性質)은 처리조건(處理條件)에 따른 다른 효과(効果)를 나타내어, 실용화(實用化)를 위해서는 원료(原料), 펄프화법(化法) 및 펄프의 용도(用途)에 따라 적절(適切)한 열처리(熱處理) 조건(條件)을 선택(選擇)하므로써, 수지함량(樹脂含量) 및 펄프품질면에서 가장 바람직한 효과(効果)를 얻을 수 있을 것으로 기대(期待)된다.

• 한국주조공학회지
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• 제40권2호
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• pp.16-24
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• 2020

The effect of a heat treatment on the microstructure and mechanical properties of Inconel 713C alloy vacuum investment castings were investigated. The microstructure of the as-cast state was observed, showing well-developed dendrite structures and distributed carbide particles and solidified massive precipitates in the grain or grain boundary during solidification, in this case the γ′ phase and MC particles. During a heat treatment, the γ phase matrix was reinforced by solid solution elements, carbide particles from the film morphology precipitated along the grain boundary, and many micro-precipitates of second γ′ phases 0.2 ㎛~2 ㎛ in size were newly formed in the γ phase matrix according to SEM-EDS analysis results. The tensile strength at a high temperature (850℃) decreased slightly becoming comparable with the room-temperature result, while the hardness value of the specimen after the vacuum heat treatment increased by approximately 19%, becoming similar to that of the as-cast condition. However, the impact values at room temperature and low temperature (-196℃) were approximated; this alloy was mostly not affected by an impact at a low temperature. In the observations of the fracture surface morphologies of the specimens after the tensile tests, the fractures at room temperature were a mix of brittle and ductile fractures, and an intergranular fracture in the inter-dendrite structure and some dimples in the matrix were observed, whereas the fractures at high temperatures were ductile fractures, with many dimples arising due to precipitation. It was found that a reinforced matrix and precipitates of carbide and the γ′ phase due to the heat treatment had significant effects, contributing greatly to the excellent mechanical properties.

• Corrosion Science and Technology
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• 제14권6호
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• pp.296-300
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• 2015

ALDC8 (Al-Si-Cu) alloy has been often corroded with pattern of intergranular corrosion in corrosive environments. Thus, in order to improve its corrosion resistance, the effect of annealing heat treatment to corrosion resistance and hardness was investigated with parameters of heating temperatures such as $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, $400^{\circ}C$ and $500^{\circ}C$ for 1hr. The hardness was varied with annealing temperature and slightly decreased with annealing heat treatment. However, the relation between annealing temperature and hardness agreed not well each other. Corrosion potential was shifted to noble direction and corrosion current density was also decreased with increasing annealing temperature. Moreover, both AC impedance at 10 mHz and polarization resistance on the cyclic voltammogram curve were also increased with increasing annealing temperature. Furthermore, intergranular corrosion was somewhat observed in non heat treatment as well as annealing temperatures at $100^{\circ}C$, $200^{\circ}C$ and $300^{\circ}C$, while, intergranular corrosion was not nearly observed at annealing temperature of $400^{\circ}C$, $500^{\circ}C$. Consequently, it is considered that the annealing heat treatment of ALDC8 alloy may be an available method not only to inhibit its intergranular corrosion but also to improve its corrosion resistance.

• 열처리공학회지
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• 제9권1호
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• pp.45-52
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• 1996

Different crystallographic planes, at a gas-metal interface, have different surface energy. To grow the (100) grains of 6.5wt%Si-Fe alloy preferentially, it was heat-treated in the atmosphere of sulfur by using the surface energy. When the specimen is heat-treated for 1 hour at $1175^{\circ}C$ by using the atmosphere of sulfur produced by heating at $75^{\circ}C$, (100) grains were grown to 3.5mm. Owing to the growth of (100) grains, the coercive force was decreased to 2.1 A/mm, and the magnetic induction at 800(A/mm) was increased to 1.61T.