In the powder bed fusion (PBF) process, a 3D shape is formed by the continuous stacking of very fine powder layers using computer-aided design (CAD) modeling data, following which laser irradiation can be used to fuse the layers forming the desired product. In this method, the main process parameters for manufacturing the desired 3D products are laser power, laser speed, powder form, powder size, laminated thickness, and laser diameter. Stainless steel (STS) 316L exhibits excellent strength at high temperatures, and is also corrosion resistant. Due to this, it is widely used in various additive manufacturing processes, and in the production of corrosion-resistant components with complicated shapes. In this study, rectangular specimens have been manufactured using STS 316L powder via the PBF process. Further, the effect of heat treatment at 800 °C on the microstructure and hardness has been investigated.

Effects of growth variables and post-growth annealing on the optical, structural and electrical properties of magnetron-sputtered Ga0.04Mg0.10Zn0.86O films are characterized in detail. It is observed that films grown from pure oxygen plasma showed high resistivity, ~102 Ω·cm, whereas films grown in Ar plasma showed much lower resistivity, 2.0 × 10− 2 ~ 1.0 × 10−1 Ω·cm. Post-growth annealing significantly improved the electrical resistivity, to 4.3 ~ 9.0 × 10−3 Ω·cm for the vacuum annealed samples and to 1.3 ~ 3.0 × 10−3 Ω·cm for the films annealed in Zn vapor. It is proposed that these phenomena may be attributed to the improved crystalline quality and to changes in the defect chemistry. It is suggested that growth within oxygen environments leads to suppression of oxygen vacancy (Vo) donors and formation of Zn vacancy (VZn) acceptors, resulting in highly resistive films. After annealing treatment, the activation of Ga donors is enhanced, Vo donors are annihilated, and crystalline quality is improved, increasing the electron mobility and the concentration. After annealing in Zn vapor, Zn interstitial donors are introduced, further increasing the electron concentration.

This study sought to investigate the effects of heat-moisture treatment (HMT) and ethanol treatment (EOH) for improving the quality and storage stability of Tteokbokki Tteok. The quality characteristics were evaluated by moisture, pH, color, texture profile analysis, and observing the microbial properties after the heat-moisture treatment or ethanol treatment. As the storage period increased, the moisture content of Tteokbokki Tteok tended to decrease except for the HMT group (p<0.05) while the pH did not show significant variation except for the EOH group (p<0.05). While measuring the color, the L-value tended to increase in all groups during the storage period. The a-value and the b-value showed the highest values in the HMT group and the control (CON) group, respectively. In the texture profile analysis, all groups showed a significant tendency to increase levels of hardness and chewiness as the storage period increased (p<0.05). The HMT group showed an increase in hardness and adhesiveness, which are characteristics of the HMT treatment. The results of examining the microbial properties of Tteokbokki Tteok showed that the total microbial count in the HMT group was 4.52 on the 8th day of storage, which was lower than the level in the CON group and the EOH group on the 4th day of storage. Yeast and mold were not measured during the storage period. Thus the results of this study showed that when manufacturing Tteokbokki Tteok, the heat-moisture treatment of rice powder increased the storage stability by delaying microbial growth and also had positive effects on quality.

Petroleum-based impregnating pitches were prepared from pyrolysis fuel oil (PFO) using a two-step heat treatment without a separation process. The pressurized heat treatment, the first step, was used to improve the properties of the pitches and enhance the product yield by promoting the cracking and polymerization of the components in the PFO. An atmospheric heat treatment as the second step was used only to synthesize the impregnating pitches from the liquid pitches prepared during the first step. The prepared impregnating pitches had the properties of a commercial petroleum-based impregnating pitch. The impregnation performance was evaluated by HT-XRD and an impregnation test. The HT-XRD results showed changes in the stacked structure of the pitches at the impregnation temperature. The bulk density of the carbon block was increased to 14.3% and the porosity was reduced by 10.3% after the impregnation/recarbonization process. The high reaction temperature during the first step induced the formation of quinoline insoluble (QI) components during the second step of the treatment, and the QI components adversely affected the impregnation process.

For enhanced cavitation erosion resistance of vessel propellers, an electroless Ni-P plating method was introduced to form a coating layer with high hardness on the surface of Cu alloy (CAC703C) used as vessel propeller material. An electroless Ni-P plating reaction generated by Fe atoms in the Cu alloy occurred, forming a uniform amorphous layer with P content of ~10 wt%. The amorphous layer transformed to (Ni3P+Ni) two phase structure after heat treatment. Cavitation erosion tests following the ASTM G-32 standard were carried out to relate the microstructural changes by heat treatment and the cavitation erosion resistance in distilled water and 3.5 wt% NaCl solutions. It was possible to obtain excellent cavitation erosion resistance through careful microstructural control of the coating layer, demonstrating that this electroless Ni-P plating process is a viable coating process for the enhancement of the cavitation erosion resistance of vessel propellers.

본 연구에서는 현재 전량 폐기되는 정수기용 폐 카본블록 필터를 재활용하고자 폐 필터의 특성을 파악한 후 열 처리를 진행하였다. 성능 평가를 위해 실제 정수기에서 사용 후 폐기되는 카본블록 필터 (도레이 케미칼에서 제조)를 회수하여 활성탄의 흡착능을 측정하였다. 대조군으로써 새 필터도 같은 조건으로 진행하였다. 재활용을 위한 열처리의 온도는 400, 550, 및 700℃로 진행하였으며 최적 조건을 찾기 위해 새 필터에 먼저 열처리를 진행하였다. 또한 TGA, DSC, SEM 및 BET를 이용하여 폐 필터의 표면 특성을 분석하였다. 이러한 결과를 바탕으로, 폐 필터 표면에 막 오염(fouling)과 정도를 확인하였으며, 폐 카본블록 필터의 재활용 및 복원기술 연구를 통한 순환 활용 기술을 확보하고자 한다.

Heating for disinfestation has been practiced of at the condition of 55-60°C for at least 48 hours in various facilities of stored and processed agricultural products. However, it has been required to reduce temperature and time due to the economic efficiency. To improve disinfestation efficiency of heating, we demonstrated whether combined treatments of heat with other agents exert synergistic for disinfestation. Heat treatments were combined with 1 ppm diatomaceous earth (DE), 10 ppm phosphine or 10% carbon dioxide against Plodia interpunctella, Sitophilus zeamais and Tribolium castaneum. Insects were treated single or multiple combinations of each component for 6 h at either 25°C or 40°C, then mortalities were monitored for 14 days post-treatments. Combined treatments greatly enhanced mortalities and shorten killing time of three species rather than single treatments. Particularly, heat treatments with 1 ppm DE and 10 ppm phosphine completely lethal within 3-6 h post-treatments, but heating with 10% CO2 was not much effective. Among three species, S. zeamais adults were more suscpetable to heat but both larvae and adults of T. castaneum was highly susceptible to phosphine. Our results clearly showed that combined treatment of DE or phosphine with mild heating (40°C) greatly improved mortalities of three major stored pest insects and provide advanced techniques for disinfestation of stored product pests.

Imported Allium hookeri is sometimes infected by some quarantine nematodes like Meloidogyne spp., Pratylenchus spp. Hot water treatment(HWT) is reported as the most effective treatment method for disinfection of nematodes. The primary goal of this research was to determine the temperature tolerance of Allium hookeri and lethal temperature of Meloidogyne spp., preferably in the range of 5~30minutes at 48~53℃. Second stage juveniles of Meloidogyne spp. were successfully eliminated in hot water bath treated at 48℃ within 1 minute. Egg hatching was suppressed completely at 48℃ more than 26 minutes. No evidence of growth damage was observed on plants treated with HWT even at 48℃ for 30 minutes and 49℃ for 10 minutes. Therefore, the optimum range of HWT is recommended at 48℃ for 30 minutes and 49℃ for 10 minutes on Allium hookeri infected root-knot(Meloidogyne spp.) nematode.

Coal-tar pitch, a feedstock which can be heat-treated to create graphite, is composed of very complex molecules. Coal-tar pitch is a precursor of many useful carbon materials (e.g., graphite, carbon fibers, electrodes and matrices of carbon/carbon composites). Modified coal-tar pitch (MCTP) was prepared using two different heat-treatment methods and their properties were characterized and compared. One was prepared using heat treatment in nitrogen gas; the other was prepared under a pressure of 350 mmHg in air. The MCTPs were investigated to determine several properties, including softening point, C/H ratio, coke yield, formation of anisotropic mesophase and viscosity. The MCTPs were subject to considerable changes in chemical composition due to condensation and polymerization in the used-as-received coal-tar pitch after heat-treatment under different conditions. The MCTPs showed considerable increases in softening point, C/H ratio, and coke yield, compared to those of as-received coal-tar pitch. The MCTP formed by heat-treatment in nitrogen showed isotropic phases below 350˚C for 1 h of soaking time. However, MCTP heat-treated under high pressure (350 mmHg) showed isotropic phases below 300˚C, and showed anisotropic phases above 350˚C, for 1 h of soaking time. The viscosity of the MCTPs increased with increase in their softening points.

살균제 저항성 Bacillus cereus 분리주의 포자에 살균제와 열을 가해 그 병합효과를 비교하였다. 사용된 B. cereus 균주는 차아염소계 처리 후 분리한 균주(S-BC-50, S-BC-52), 과산화수소 처리 후 분리한 균주(S-BC-23, S-BC-48), acetic acid 처리 후 분리한 균주(S-BC-54, S-BC-56)와 표준균주 B. cereus KCTC1661을 사용하였다. B. cereus 분리주의 포자를 다음 조건으로 처리하였다; i) 0.56% 과산화수소수(HP), ii) 3% acetic acid(AA), iii) 80oC 열처리(H80), iv) 90o 열처리(H90), v) HP+H80, vi) HP+H90, vii) AA+H80, viii) AA+H90. 포자를 HP와 AA 처리에 노출시킨 결과 포자가 감소하지 않았지만, H80과 H90 처리에서는 1~2 log CFU/mL가 감소하였다(P<0.05). 병합처리(HP+H80, HP+H90, AA+H80, AA+H90)에 포자를 적용시킨 경우, 포자수가 3-6 log CFU/mL 감소 하였지만, AA+H80과 AA+H90은 AA만 처리했을 때보다 오히려 포자 제어가 감소했다. 따라서 HP와 열처리를 병합했을 때는 B. cereus 포자를 불활성화하기에 효과적이지만, AA의 경우 B. cereus 포자가 열처리에 대한 저항성을 증가시키는 것으로 사료된다.

3%C-10%Cr-5%Mo-5%W, 3%C-10%V-5%Mo-5%W 및 3%C-17%Cr-3%V의 3종류 고합금백주철에 있어서 열처리후의 기지조직의 변태거동을 연구하였다. 15kg 용량의 고주파 유도용해로에 선철, 고철, Fe-Cr, Fe-V, Fe-Mo 및 Fe-W 등을 장입시켜 용해시킨 후 슬래그를 제거시키고 1550˚C에서 Y-block의 펩 주형에 주입시켰다. 적당한 크기로 절단한 시편을 진공분위기하에950˚C에서 5시간동안 우선 균질화처리를 실시하였다. 그 후 다시 이 시편을 1050˚C에서 2시간동안 오스테나이징시킨 후 강제공냉을 행하였다. 강제공냉된 시편을 300˚C에서 3시간 유지시킨 후 템퍼링을 실시하였다. 주방상태에서의 기지조직은 3합금 공히 퍼얼라이트이었으며 강제공냉후에는 마르텐사이트 및 오스테나이트로 변태하였다. 또한 기지조직내에 무수히 많은 이차탄화물 입자들의 석출되었다. 템프링 후 일부 오스테나이트 및 마르텐사이트는 템퍼드마르텐사이트로 변태하였다. 변태하였다.

6H-SiC와 W의 계면에서 열처리에 따라 일어나는 반응을 X-선 회절분석 및 투과전자현미경을 이용하여 분석하였다. 연구결과 900˚C까지 새로운 상의 형성은 없었고, 1100˚C와 1300˚C에서 W5Si3와 W2C가 형성되어 서로 혼재되어 있으며 반응하지 않은 W은 없음을 관찰하였다. 이는 이미 보고된 W/β-SiC의 경우와 일치하는 결과로서 이 온도영역에서 W5Si3와 W2C가 안정상임을 시사하고 있다.

본 논문에서는 전자빔증착법에 의해 제조된 다결정 CdTe 박막의 구조적, 광학적 특성을 연구하였으며 특히 기판온도와 증착후 열처리에 따른 박막의 결정성변화를 관찰하고 그 결과를 고찰하였다. ITO와 유리위에 25~160˚C의 기판온도로 증착된 CdTe 박막의 결정구조는 zinc blende 구조를 보이고<111> 방향으로의 우선 성장방향을 나타내었다. 증착후 열처리를 함에 따라 결정립이 성장하고 정량적 CdTe로 접근하고 상온에서 band gap 이 단결정의 값인 1.5eV에 가까운 에너지로 천이하며 결정성이 향상됨을 관찰할 수 있었다. 이러한 열처리에 의한 결정성 향상은 PL과 XRD를 통하여 분석한 결과 재료내 존재하는 과잉 Te가 열처리시 증발함에 따라 격자내 응력이 감소함과 관련이 있음을 알 수 있었다.

The present study was carried out to investigate the physicochemical properties of hot water extracts of red ginseng powder prepared by two-stage hot air drying method using steamed ginseng and steaming liquid for 2.5 h under high-temperature and high-pressure autoclave condition. The total polyphenols, total flavonoids, total sugar, acid polysaccharides and crude saponin in hot water extracts from red ginseng powder were analyzed and determined, and the flavor components of ginseng were measured using color difference meter and an electronic tongue. The total polyphenol, total flavonoid, total polysaccharide, and acid polysaccharide of the red ginseng hot water extract obtained by autoclaving (ARG) were 9.06 mg GAE/g, 3.38 mg NE/g, 35.22 g/100 g, and 10.90 g/100 g, respectively. The final contents of the total polyphenols, total flavonoids, crude saponin were higher than those determined using other red ginseng methods; the time required for steamed red ginseng production reduced. The total ginsenoside content of ginseng including Rb1 was 10.69 mg/g, which is the lowest ARG. The processing conditions affected the conversion to ginsenosides unique to red ginseng. Red ginseng and steaming liquid obtained from the autoclave are expected to be in need for non-food materials and products as well as foods by improving the flavor components through conversion of red ginseng components into low molecular weight.

절단 배추를 예열처리하고 LDPE 필름 포장하여 단기저장하면서 이화학적인 품질특성과 갈변도를 조사하였다. 40℃에서 1, 2, 4, 8시간동안 예열처리한 후 SDS-PAGE 법으로 단백질 밴드를 조사한 결과, 예열처리구에서 대조구에 비하여 HSP 밴드로 추정되는 60, 39, 33, 12 kDa 밴드가 강하게 나타났으며, 이 중 4시간 예열처리구(HS 4)가 가장 발현율이 높았으며 중량감소율도 적었다. 8주 동안 저장 중 예열처리한 절단배추의 중량감소율 및 적정산도는 거의 변화가 없었으며, 가용성 고형분 함량은 4시간 예열처리구가 가장 적게 감소하였다. 갈변도는 HS 4가 가장 적었다(Con>HS 1>HS 8>HS 2>HS 4, p<0.05). PPO활성은 저장 중 모든 구에서 지속적으로 증가하였으며, HS 4가 가장 낮았고 총페놀성 화합물은 모든 처리구에서 유사하게 감소하였다. 예열처리한 절단배추에서 HSP 밴드의 발현을 확인하였으며, 4시간 예열처리구의 단기 저장 효과가 가장 좋았다.

본 연구는 환경 친화적인 새싹채소류의 고품질화를 위한 경제적이고 효율적인 살균기술을 개발할 목적으로 국내산 적무 종자의 다양한 열처리 방법에 따른 발아율과 미생물 저감효과를 조사하였다. 열수처리는 60, 65, 70, 75, 80, 90℃에서 각각 30, 60초간 실시하였고, 건열처리는 70, 80, 90, 100℃에서 5분간 실시하였다. 열수 처리에 따른 미생물의 제어효과는 시간에 따른 유의적인 차이는 보이지 않았으나, 온도변화에 따른 유의적인 차이를 나타내었다 (p<0.001). 70℃ 이상의 온도에서 총세균수는 3 logs 이상의 감소를 보였으며, L. monocytogenes는 검출되지 않았다. 건열처리는 온도변화에 따른 유의적인 차이를 나타내었다 (p<0.001). 100℃에서 5분간 처리한 후 총세균과 L.monocytogenes 수는 3 logs 이하 감소하였다. 열수처리에 따른 발아율의 변화는 처리 전과 후 모두 시간에 따른 유의적인 차이는 보이지 않았으나, 75℃ 이상의 온도에서 온도증가에 따라 유의적으로 감소하였다(p<0.001). 한편, 열수처리 후 침지시킨 종자에서 발아가 더 촉진되는 것으로 나타났다. 건열처리에 따른 발아율은 80℃ 이상의 온도에서 온도 증가에 따라 유의적으로 감소하였다(p<0.001). 건열처리한 후 증류수에 3시간 침지시킨 종자의 발아율은 90℃ 이상의 온도에서 유의적으로 감소하였다(p<0.05). 결론적으로 적절한 열처리는 75℃, 30분 이상의 열수처리하는 방법으로, 적무 새싹채소의 종자의 미생물학적 안전성을증가시킴과동시에발아율을증가시키는것으로판단된다.