• Title/Summary/Keyword: thermal processing

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Effect of Stabilization Processing Conditions on the Thermal Shrinkage and the Thermal Stability of Rayon Fabrics Untreated and Surface-Treated with Phosphoric Acid (인산처리 유·무에 따른 레이온직물의 열수축과 열안정성에 미치는 안정화 공정 조건의 영향)

  • Cho, Donghwan;Lee, Jongmoon;Park, Jong Kyoo
    • Journal of Adhesion and Interface
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    • v.5 no.3
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    • pp.10-17
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    • 2004
  • We investigated the effect of stabilization processing parameters on the thermal shrinkage, thermal stability and microstructure of rayon fabrics stabilized under various conditions such as heating rate, stabilization temperature, atmosphere gas, and chemical treatment. The presence and absence of phosphoric acid treatment and the heating rate have most importantly influenced the thermal shrinkage and the weight change of rayon fabrics. Especially, the phosphoric acid treatment decreases the reduction of thickness, length, and weight of the fabrics by about 80%, 20%, and 26%, respectively, in comparison with the untreated counterparts, showing the protective effectiveness of the thermal shrinkage involved. The thermal stability of stabilized rayon fabrics is also affected by all the processing conditions used: stabilization temperature, phosphoric acid treatment, atmosphere gas, and heating rate. In addition, the surface and diameter of the stabilized fiber significantly depend on the treatment of phosphoric acid prior to stabilization process.

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Retort Processing of Packaged Foods (포장식품의 레토르트 공정)

  • Chung, Dong-Hwa
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.13 no.2
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    • pp.59-65
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    • 2007
  • Packaged food products often undergo retort processing, a thermal processing in a pressurized vessel called a retort, to ensure their microbiological safety or shelf-stability under normal non-refrigerated conditions of storage and distribution. Retort processing is generally aimed to accomplish commercial sterility of packaged foods with acceptable nutritional and sensorial qualities. Fundamental principles on retort processing, such as thermal resistance kinetics of target microorganism, heat penetration theory, and methods for evaluating process sterility and food quality loss, were reviewed. Factors affecting process severity, heat transfer mechanism, and heat penetration efficiency were summarized. General features of retortable packaging formats including metal cans, glass jars, and plastic packages were also briefly reviewed.

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Dynamic Thermal Rating of Overhead Transmission Lines Based on GRAPES Numerical Weather Forecast

  • Yan, Hongbo;Wang, Yanling;Zhou, Xiaofeng;Liang, Likai;Yin, Zhijun;Wang, Wei
    • Journal of Information Processing Systems
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    • v.15 no.4
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    • pp.724-736
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    • 2019
  • Dynamic thermal rating technology can effectively improve the thermal load capacity of transmission lines. However, its availability is limited by the quantity and high cost of the hardware facilities. This paper proposes a new dynamic thermal rating technology based on global/regional assimilation and prediction system (GRAPES) and geographic information system (GIS). The paper will also explore the method of obtaining any point meteorological data along the transmission line by using GRAPES and GIS, and provide the strategy of extracting and decoding meteorological data. In this paper, the accuracy of numerical weather prediction was verified from the perspective of time and space. Also, the 750-kV transmission line in Shaanxi Province is considered as an example to analyze. The results of the study indicate that dynamic thermal rating based on GRAPES and GIS can fully excavate the line power potential without additional cost on hardware, which saves a lot of investment.

Low temperature UV-assisted rapid thermal processing of (Ba,Sr)$TiO_3$ thin films (저온에서 (Ba,Sr)$TiO_3$ 박막의 UV를 이용한 RTP에 관한 연구)

  • Cho, Kwang-Hwan;Kang, Chong-Yun;Yoon, Seok-Jin;Lee, Young-Pak
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.234-234
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    • 2008
  • Chemically homogeneous $Ba_{0.6}Sr_{0.4}TiO_3$ (BST) sols were synthesized using barium acetate, strontium acetate, and titanium isoproxide as starting materials. BST thin films of thickness 340 nm were deposited on Pt/$TiO_2/SiO_2$/Si and alumina substrates using spin coating method. The technique used for the processing of these films was Ultraviolet (UV) sol-gel photoannealing, using phto-sensitivity precursor solutions and UV-assisted rapid thermal processing(UV-RTP). The crystallization behaviour of the BST sols and thin films was studied by differential thermal analysis (DTA) and X-ray diffraction (XRD). Variation of permittivity and dielectric loss were measured in LCR-meter, model HP 4394A.

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A robust controller design for rapid thermal processing in semiconductor manufacturing

  • Choi, Byung-Wook;Choi, Seong-Gyu;Kim, Dong-Sung;Park, Jae-Hong
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.79-82
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    • 1995
  • The problem of temperature control for rapid thermal processing (RTP) in semiconductor manufacturing is discussed in this paper. Among sub=micron technologies for VLSI devices, reducing the junction depth of doped region is of great importance. This paper investigates existing methods for manufacturing wafers, focusing on the RPT which is considered to be good for formation of shallow junctions and performs the wafer fabrication operation in a single chamber of annealing, oxidation, chemical vapor deposition, etc., within a few minutes. In RTP for semiconductor manufacturing, accurate and uniform control of the wafer temperature is essential. In this paper, a robustr controller is designed using a recently developed optimization technique. The controller designed is then tested via computer simulation and compared with the other results.

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A study on the Thermal Stress Distribution for Wire Electrical Discharge by Finite Element Method (와이어 방전 가공 시 발생되는 열응력 분포에 관한 유한요소법적 고찰)

  • 반재삼;김승욱;김선진;조규재
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.210-213
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    • 2002
  • The Purpose of this study is to know temperature and thermal stress distribution in specimens during processing of WEDM. If it is constant to the cutting speed and the thickness of material, it is very important to the effect of temperature and the thermal stress distribution after cutting processing. This paper show the analysis result of the distribution of temperature and the residual stress along the direction of thickness before processing of WEDM and after when the cooling temperature is$20^{\circ}C$. The maximum temperature of edge of specimens is $1600^{\circ}C$. It has little temperature gradient in the depth which is 5mm away from edge of specimens. Equivalent residual stress is result in 180.7 MPa at maximum temperature.

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CTD Data Processing for CREAMS Expeditions: Thermal-lag Correction of Sea-Bird CTD

  • Kim, Kuh;Cho, Yang-Ki;Ossi, Hyong;Kim, Young-Gyu
    • Journal of the korean society of oceanography
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    • v.35 no.4
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    • pp.192-199
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    • 2000
  • Standard CTD data processing recommended by Sea-Bird Electronics produced thermal-lag corrections larger than 0.1 psu for the data taken during the CREAMS expeditions in the northern part of the East/Japan Sea where a vertical temperature gradient frequently exceeds 1.0$^{\circ}$C/m in the upper 100 m near the sea surface. As the standard processing is based upon a recursive filter which was introduced by Lueck and Pickle (1990), coefficients of the recursive filter have been newly derived for the CREAMS data by minimizing the difference between salinities of downcast and upcast in temperature-salinity domain. The new coefficients are validated by comparison with salinities measured by a salinometer, AUTOSAL 8400B. An accurate correction for the thermal-lag is critical in identifying water masses at intermediate depth in the East/japan Sea.

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Fabrication and characteristics of PZT ferroelectric thin films by Sol-Gel processing and rapid thermal annealing (Sol-gel법과 급속 열처리에 의한 PZT 강유전 박막의 제작과 그 특성)

  • 백동수;최형욱;김준한;신현용;김규수;박창엽
    • Electrical & Electronic Materials
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    • v.7 no.5
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    • pp.369-375
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    • 1994
  • In this study, ferroelectric thin films of PZT with different Zr/Ti ratio were prepared by sol-get processing and annealed by rapid thermal annealing at >$500^{\circ}C$>$-700^{\circ}C$ for 10 sec. -1 min. Structures of the annealed films were examined by X-ray diffraction and SEM. Thin films of PZT with perovskite structure have been obtained by annealing at >$600^{\circ}C$ or above and for 20 seconds or longer. Maximum remnant polarization of 10.24.mu.C/cm$^{2}$ and minimum coercive field of 20.06 kV/cm were obtained from the 56/44 and 65/35 Zr/Ti composition films, respectively. Dielectric constant, .epsilon.$_{r}$ of 500-1300 and dielectric loss, tan .delta., of 0.01-0.035 were obtained from the films.s.

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Effect of coating thickness on contact fatigue and wear behavior of thermal barrier coatings

  • Lee, Dong Heon;Jang, Bin;Kim, Chul;Lee, Kee Sung
    • Journal of Ceramic Processing Research
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    • v.20 no.5
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    • pp.499-504
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    • 2019
  • The effect of coating thickness on the contact fatigue and wear of thermal barrier coatings (TBCs) are investigated in this study. The same bondcoat material thickness (250 ㎛) are used for each sample, which allows the effect of the coating thickness of the topcoat to be investigated. TBCs with different coating thicknesses (200, 400, and 600 ㎛) are prepared by changing processing parameters such as the feeding rate of the feedstock, spraying speed, and spraying distance during APS(air plasma spray) coating. The damage size on the surface are strongly affected by the coating thickness effect. Although the damage size from contact fatigue using a spherical indenter diminish at a TBC of 200 ㎛, a high wear resistance such as a low friction coefficient and little mass change are found at a TBC of 600 ㎛. These results indicate that the coating thickness strongly affects the mechanical behavior in TBCs during gas turbine operation.

Physical Property Evaluation for High Purity Niobium and Tantalum Rare Metals (고순도 나이오븀과 탄탈륨 희유금속의 물리적 특성평가)

  • Kim Il-Ho;Park Jong-Bum;You Sin-Wook;Cho Kyung-Won;Choi Good-Sun;Suh Chang-Youl;Kim Byoung-Gyu;Kim Joon-Soo
    • Korean Journal of Materials Research
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    • v.15 no.4
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    • pp.217-223
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    • 2005
  • Thermal, electrical and mechanical properties of high purity niobium and tantalum refractory rare metals were investigated tn evaluate the physical purity. Higher purity niobium and tantalum metals showed lower hardness due to smaller solution hardening effect. Temperature dependence of electrical resistivity showed a typical metallic behavior. Remarkable decrease in electrical resistivity was observed for a high purity specimen at low temperature. However, thermal conductivity increased for a high purity specimen, and abrupt increase in thermal conductivity was observed at very low temperature, indicating typical temperature dependence of thermal conductivity for high purity metals. It can be known that reduction of electron-phonon scattering leads to increase in thermal conductivity of high purity niobium and tantalum metals at low temperature.