• Carbon letters
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• 제15권4호
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• pp.247-254
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• 2014

In this work, thermal treatment accompanied with different acid treatments was applied to a commercial coal tar pitch (CTP) to obtain a spinnable precursor pitch for carbon fiber. In the case of thermal treatment only, a relatively high reaction temperature of between $380^{\circ}C$ and $400^{\circ}C$ was required to obtain a softening point (SP) range of $220^{\circ}C-260^{\circ}C$ and many meso-phase particles were created during the application of high reaction temperature. When nitric acid or sulfuric acid treatment was conducted before the thermal treatment, the precursor pitch with a proper SP range could be obtained at reaction temperatures of $280^{\circ}C-300^{\circ}C$, which were about $100^{\circ}C$ lower than those for the case of thermal treatment only. With the acid treatments, the yield and SP of the precursor pitch increased dramatically and the formation of meso-phase was suppressed due to the lower reaction temperatures. Since the precursor pitches with acid and thermal treatment were not spinnable due to the inhomogeneity of properties such as molecular weight distribution and viscosity, the CTP was mixed with ethanol before the consecutive nitric acid and thermal treatments. The precursor pitches with ethanol, nitric acid, and thermal treatments were easily spinnable, and their spinning and carbon fiber properties were compared to those of air blowing and thermal treated CTP.

• 한국재료학회지
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• 제30권9호
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• pp.474-479
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• 2020

The effect of precipitation and dissolution of Si on the thermal diffusivity in the Al-Si alloy system is reported in this study and solution heat treatment followed by aging treatment is carried out to determine the effects of heat treatment on the thermal characteristics. The solution treatment is performed at 535 ℃ for 4 and 10 h and then the specimens are cooled by rapid quenching. The samples are aged at 300 ℃ for 4 h to precipitate Si solute. The addition of 9 wt% silicon contents makes the thermal diffusivity decrease from 78 to 74 mm/s² in the cases of solid solution treated and quenched samples. After quenching and aging, the Si solute precipitates on the Al matrix and increases the thermal diffusivity compared with that after the quenched state. In particular, the increase of the thermal diffusivity is equal to 10 mm/s² without relation to the Si contents in the Al-Si alloy, which seems to corresponded to solute amount of Si 1 wt% in the Al matrix.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2006년도 정기총회 및 제37차 춘계 국제학술발표대회
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• pp.325-328
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• 2006

In low nitrite level, treatment of combined with pressure and thermal processing improved cured meat colour comparing with that of only thermal processing. However, visual colour of only pressurised treatment could not be improved at low nitrite level. Pressure treatment could develop cured meat colour when high nitrite level was added. Moreover, pressurisation combined with thermal processing decreased nitrite residuals compared to thermal processing. Therefore the results indicated that pressurisation combined with thermal processing had potential benefits in appearance of cured meat products, promising improved food safety.

• 폴리머
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• 제35권6호
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• pp.605-609
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• 2011

전기방사법과 열처리 공정을 통하여 PVDF-$SiO_2$ 복합나노섬유를 제조하였으며, 얻어진 나노섬유는 서로 연결된 기공으로 이루어진 적층 구조를 하고 있었다. 즉, 전기방사로 제조된 나노섬유는 직경이 380 nm, 기공도가 80% 이상인 다공성막을 형성하였다. TEM 사진과 EDX 스펙트라의 분석 결과로부터 $SiO_2$가 나노섬유에 균일하게 분산되어 존재한다는 것이 확인되었다. 또한 전기방사법의 도입에 의해 나노섬유의 기공도가 현저히 개선되었다. ATR-FTIR 및 XRD 분석 결과 복합나노섬유 상에서 PVDF는 ${\alpha}$-phase와 ${\beta}$-phase가 혼재되어 있는 결정구조를 가지고 있었으며, 열처리에 의해서 PVDF의 ${\alpha}$-phase가 증가하였으며, 이로 인해 결정화도가 증가하였다. 특히, 기계적 강도, 열적 특성 및 소수성은 열처리 공정에 의해서 매우 증가되는 것을 확인할 수 있었다.

• 열처리공학회지
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• 제34권4호
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• pp.159-164
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• 2021

The Improvement of thermal performance using heat treatment of carbon nanotubes coated on the copper heat sink to take the radiation energy from solar ray for the energy harvesting in earth orbit. Using the additive coating of purified CNT for the increase of specific area and development of thermal conductive capacity, the performance of heat transfer is improved about 0.181 K/W while applying the power of 22 W under temperature of 3.98℃. Coating of purified CNT shows increase of area and volume of thermal layer however it led the partial thermal resistance.

• 접착 및 계면
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• 제5권3호
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• pp.10-17
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• 2004

본 연구에서는 레이온직물에 대하여 승온속도, 안정화온도, 분위기가스, 화학적 표면처리 등 여러가지 조건에서 안정화공정을 행한 후, 직물의 열수축과 열안정성, 그리고 미세구조에 미치는 공정 조건의 영향을 조사하였다. 레이온직물의 열수축과 중량변화에 인산처리 유무와 승온속도가 가장 중요한 영향을 미쳤다. 특히, 인산처리를 한 경우가 하지 않은 경우보다 레이온직물의 두께변화는 약 80%, 길이변화는 약 20%, 그리고 중량변화는 약 26%가 줄어드는 열수축 억제 효과를 보여주었다. 안정화 된 레이온직물의 열안정성에는 안정화온도와 인산처리 그리고 분위기가스와 승온속도 등 주어진 안정화공정 조건 모두가 영향을 주었다. 또한 안정화섬유의 표면 상태 및 섬유직경 변화도 공정 전에 행한 인산처리의 유무에 의존하였다.

• 한국응용과학기술학회지
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• 제32권1호
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• pp.127-135
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• 2015

The aim of this study was to investigate the antioxidant activity of thermal treatment yam (Dioscorea batatas DECNE.) in Korea. Thermal treatment yam was extracted by different solvents including 70% methanol, 70% ethanol and chloroform-methanol mixture (CM, 2:1, v/v). Then color property, total phenol content and antioxidant activity were analyzed. Yam possessed high $L^*$ value and $H\limits^{\circ}$ value, which were $54.92{\pm}2.18$ and $73.20{\pm}0.77$, respectively. Thermal treatment yam exhibited great antioxidant activity evaluated by ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power. Total phenol contents of various extracts from thermal treatment yam increased in the following order: 70% methanol extract ($63.53{\pm}0.33mg\;CAE/g$), 70% ethanol extract ($69.47{\pm}1.00mg\;CAE/g$) and CM extract ($97.49{\pm}0.66mg\;CAE/g$), respectively. The same trend was also could be found in antioxidant activity assays except for reducing power assay. These results implied that these extracts from thermal treatment yam might be useful to take a good part in prevention of human diseases and aging.

• 한국축산식품학회지
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• 제42권1호
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• pp.142-152
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• 2022

The present study was aimed at examining the antibacterial effects of nonthermal decontamination processes, which are equivalent to thermal treatment, to ensure microbiological safety of raw ground chicken. Escherichia coli or Salmonella were inoculated into 25 g of raw ground chicken samples. The raw ground chicken samples were non-treated or treated with high hydrostatic pressure (HHP) at 500 MPa (1-7 min), light-emitting diode (LED) irradiation at 405 nm wavelength (30-120 min), and heat at 70℃, 90℃ (1-60 min), and 121℃ (1-15 min). E. coli and Salmonella cell counts were enumerated after treatments. Moreover, the color parameters of treated raw ground chicken were analyzed. HHP treatment reduced E. coli and Salmonella cell counts by more than 5 Log CFU/g and more than 6 Log CFU/g after 7 min and 1 min, respectively; these effects were equivalent to those of thermal treatment. However, LED irradiation reduced Salmonella cell counts by only 0.9 Log CFU/g after 90 min of treatment, and it did not reduce E. coli cell counts for 90 min. Compared with those of the non-treated samples, the ΔE (total color difference) values of the samples treated with HHP were high, whereas the ΔE values of the samples treated with LED irradiation were low (1.93-2.98). These results indicate that despite color change by HHP treatment, HHP treatment at 500 MPa could be used as a non-thermal decontamination process equivalent to thermal treatment.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.184-190
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• 2016

Recently, wood is attracting attention as green building interior decoration material. When wood is used as building interior decoration material, excellent dimensional stability and thermal performance is required. In this study, superheated steam treatment process and thermal compression process were applied to flat sawn Pinus koraiensis wood panel in order to improve dimensional stability and thermal performance. According to results of this study, superheated steam treatment process and thermal compression process improve thermal performance and dimensional stability of wood, especially in tangential direction. The spring back in radial direction reduces the effect of thermal compression on dimensional stability of wood in radial direction.

• 열처리공학회지
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• 제23권2호
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• pp.83-89
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• 2010

Diamond-like carbon (DLC) coating was studied to be a good tribological problem-solver due to its low friction characteristics and high hardness. However, generally hydrogenated DLC film has shown a weak thermal stability above $300^{\circ}C$. However, the silicon doping DLC process by DC pulse plasma enhanced chemical vapor deposition (PECVD) for the new DLC coating which has a good characterization with thermal stability at high temperature itself has been observed. And we were discussed a process for optimizing silicon content to promote a good thermal stability using various tetramethylsilane (TMS) and methane gas at high-temperature. The chemical compositions of silicon-containing DLC film was analyzed using X-ray photoelectron spectroscopy (XPS) before and after heat treatment. Raman spectrum analysis showed the changed structure on the surface after the high-temperature exposure testing. In particular, the hardness of silicon-containing DLC film showed different values before and after the annealing treatment.