• Journal of Welding and Joining
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• 제11권2호
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• pp.53-61
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• 1993

One of the most interesting and promising steel groups considered for the rocket motor case, aircraft and aerospace component is the maraging(martensitic plus aging) nickel steel, developed by International Nickel Company in 1960. This material attains a very high strength with good fracture toughness by simple heat treatments which do not involve a quenching. Full strength can be obtained by "maraging" at 480.deg. for 3 hours for the 18% Ni maraging steel. The effect of heat treatments was considered on the residual stress field of 18% Ni maraging steel weldments. In experiments, various heat treatments such as stress relieve heat treatment, aging and solution heat treatment were carried out of the GTA weldments and the residual stresses were measured by using the hole drilling method. Whereas the conventional pattern of residual stress shows the stresses to be maximum along the weld centerline with tensile stress extending into the heat affected zone, the pattern in maraging steels shows the centerline stress to be compressive. After welding, a series of aging, solution heat treatment and solution heat treatment plus aging treatment were carried out and the residual stresses were measured to reveal that these heat treatments almost completely remove the welding residual stresses.

• 대한한의학방제학회지
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• 제24권1호
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• pp.31-43
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• 2016

Objectives Based on related literature, cold and heat, deficiency and excess, true and false, and actually used formulas, paradoxical treatments presented in the 『Plain Questions of Inner Canon of Yellow Emperor』 including ‘treating pseudo-heat symptoms and real cold syndrome with cold herbs, treating pseudo-heat symptoms and real cold syndrome with cold herbs’ were analyzed.Methods Out of literature, paradoxical treatment related classics and papers were investigated and analyzed. Among diseases and syndromes, real cold syndrome with pseudo-heat symptoms, real heat syndrome with pseudo-cold symptoms, real deficiency syndrome with pseudo-excess symptoms, and real excess syndrome with pseudo-deficiency symptoms were reviewed. Among formulas, typical examples of the above mentioned paradoxical treatments were used as examples to analyze paradoxical treatments.Results Treating pseudo-heat symptoms and real cold syndrome with cold herbs is a method that uses herbs with cool and cold nature to treat real cold syndrome with pseudo-heat symptoms and Tongmaeksayeokgajeodamjeuptang is suitable for this method. Treating pseudo-cold symptoms and real heat syndrome with hot herbs is a method that uses herbs with warm and hot nature to treat real heat syndrome with pseudo-cold symptoms and Baekhogainsamtang is suitable for this method.Conclusions Based on the related literature, cold and heat, deficiency and excess, true and false, and actually used formulas examined as mentioned above, the paradoxical treatments presented in the 『Plain Questions of Inner Canon of Yellow Emperor』 are thought to be reasonable paradoxical treatments that fit the diseases and syndromes that actually appeared in our bodies.

• 소성∙가공
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• 제11권3호
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• pp.211-216
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• 2002

The mechanical and thermal load, and thermal softening occuring by the rush temperature of die, in warm and hot forging, cause wear, heat cracking and plastic deformation, etc. This paper describes the effects of solid lubricants and surface treatments for warm forging die. Because cooling effect and low friction are essential to the long life of dies, optimal surface treatments and lubricants are very important to hot and warm forging process. The main factors affecting die hardness and heat transfer, are surface treatments and lubricants, which are related to heat transfer coefficient, etc. To verify the effects, experiments are performed for heat transfer coefficient in various conditions - different initial billet temperatures and different loads. Carbonitriding and ionitriding are used as surface treatments, and oil-base and water-base graphite lubricants are used. The effects of lubricant and surface treatment for warm and hot forging die life are explained by their thermal characteristics, and the new developed technique in this study for predicting tool life can give more feasible means to improve the tool life in hot forging process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.833-836
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• 2000

The mechanical and thermal load. and thermal softening which is happened by the high temperature of die, in hot and warm forging, cause wear. heat checking and plastic deformation, etc. This study is for the effects of solid lubricants and surface treatments for warm forging die Because cooling effect and low friction are essential to the long lift of dies. optimal surface treatments and lubricants are very important to hot and warm forging Process. The heat that is generated by repeated forging processes. and its transfer are important factors to affect die life. The main factors, which affect die hardness and heat transfer, are surface treatments and lubricants, which are related to thermal diffusion coefficient and heat transfer coefficient, etc. For verifying these. experiments art performed for diffusion coefficient and heat transfer coefficient in various conditions - different initial billet temperatures and different loads. Carbonitriding and ionitriding are used as surface treatments. and oil- base and water-base graphite lubrirants are used. The effects of lubricant and surface treatment for warm forging die lift are explained by their thermal characteristics.

• 대한치과보철학회지
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• 제38권5호
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• pp.575-582
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• 2000

This investigation was designed to determine whether heat-pressing and/or simulated heat treatments affected the flexure strength and the microstructure of the lithium disilicate glass-ceramic in the IPS Empress 2 system. Four groups of the specimens were prepared as follows: group 1 - as-received material, group 2 - heat-pressed material; group 3 - heat-pressed and simulated initial heat-treated material; group 4 - heat-pressed and the simulated heat-treated material with full firings for a final restoration. The three-point bending test and the scanning elec-tron microscope (SEM) analysis was conducted for the purpose of this study. The flexure strength of group 2 was significantly higher than that of group 1. However, there were no significant differences in strength among group 2, 3, and 4, and between group 1 and 4. The SEM micrographs of the lithium disilicate glass-ceramic showed the closely packed, multi-directionally interlocking microstructure of numerous lithium disilicate crystals protruding from the glass matrix. The crystals of the heat-pressed materials (group 2, 3, and 4) were a little denser and about two times bigger than those of the as-received material (group 1). This change of microstructure is more obviously exhibited particularly between group 1 and 2. However, there was no a marked difference among group 2, 3, and 4 after the heat-pressing procedure. Although there were significant increase of the strength and some changes of the microstructure after the heat-pressing operation, the combination of the heat-pressing and the simulated subsequent heat treatments did not produce the increase of strength of IPS Empress 2 glass-ceramic.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.34-34
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• 2010

We report on the influence of heat treatments on the electrical properties of ZnO films grown by molecular-beam epitaxy. We note that the electrical resistance of the ZnO films is significantly changed by the heat treatments: the electrical resistance increases with the increase of ambient temperature, but above a critical temperature the resistance decreases with the increase of temperature, irrespective of ambient gases. On the other hand, it is found that the large amount of photocurrent is generated in the ZnO films, exposed to white sources: the photocurrent decreases with the increase of the obtained resistance, and the current increases with the decrease of the resistance. Also, it is shown that the X-ray diffraction linewidth of the ZnO films is significantly decreased by the heat treatments. These indicate that the increase/decrease of the electrical resistance is ascribed to the annihilation/formation of the residual donor-type defects in the ZnO films by the heat treatments. It is suggested that the increase of the electrical resistance is due to the annihilation of Zni-complex defects, while the decrease of the electrical resistance is due to the formation of VO-complex defects.

• 한국세라믹학회지
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• 제29권4호
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• pp.273-282
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• 1992

The effects of intrinsic and extrinsic gettering on the formation of microdefects in the wafer and on the electrical performance at near-surfaces of three different oxygen-bearing Czochralski silicon single crystal wafers were investigated by varying the combinations of the pre-heat treatments and the phosphorus diffusion through the back-surface of the wafers. The wafers which had less than 10.9 ppma of oxygen formed no gettering zones irrespective of any pre-heat treatments, while the wafers which had more than 14.1 ppma of oxygen and were treated by Low+High pre-heat treatments generated the gettering zone comprising oxygen precipitates, staking faults, and dislocation loops. The effects of extrinsic gettering by phosphorus diffusion were evident in all samples such that the minority carrier lifetimes were increased and junction leakage currents were decreased. However, the total gettering effects among the different pre-heat treatments did not necessarily correspond to the gettering structure revealed by synchrotron radiation section topograph.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.186-189
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• 2008

The flex plate, an automotive part which mounts to the automotive engine to transfer torque to transmission, should have considerable hardness and shape accuracy. As a way to produce the flex plate, the hot press forming technology which takes advantages of high formability at elevated temperature, enhanced strength and shape stability was introduced. Therefore, as one of major process parameters the heat treatment condition should be determined to obtain appropriate hardness in the range of manufacturer's specifications. In this study, two heat treatments, austempering and quenching and tempering (QT), were compared as feasible conditions fur the hot press forming of high-carbon tool steel and the hardness and toughness after heat treatments were evaluated. The study showed that both heat treatments resulted in improved hardness but only quenching and tempering showed practicable range of toughness.

• Asian-Australasian Journal of Animal Sciences
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• 제13권4호
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• pp.535-542
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• 2000

Canola meal and seed are poor sources of ruminal undegraded protein (RUP). On average, canola meal and canola seed contains 35 and 14% RUP, respectively. Several protection methods are effective in reducing ruminal degradation of canola protein and in increasing RUP without affecting total tract protein digestibility. Heat (e.g., dry heat, moist heat and jet-sploding) and chemical (e.g., formaldehyde) treatments are the most common methods used to reduce ruminal degradability of canola protein. In most cases, heat treatments were found to be more effective than chemical treatments in protecting canola protein form ruminal degradation. Despite improvement in RUP content and intestinal availability of RUP, data form several studies showed little or no improvement in animal performance as a result of increasing the RUDP level of canola meal and seed.

• 한국식품영양과학회지
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• 제46권6호
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• pp.688-694
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• 2017

퀴노아의 열처리 가공방법이 퀴노아의 이화학적 특성과 in vitro 생리활성에 미치는 영향을 조사하였다. 퀴노아의 가열처리로 열탕처리와 증자 후 볶음처리 하는 두 가지 방법을 사용하였다. 퀴노아의 일반성분은 열탕처리 하였을 때 조단백질, 조지방, 조회분, 전분 함량이 약간 감소하였으나 증자/볶음처리 시에는 이들 함량에 유의적인 차이가 없었다. 퀴노아의 총 페놀 함량은 증류수 또는 80% 에탄올 용매 추출물 모두에서 원곡보다 가열처리에 의해 감소하는 것으로 나타났는데 열탕처리가 증자/볶음처리에 비해 감소가 더 큰 편이었다. 총 플라보노이드 함량 또한 두 가지 용매 추출물 모두에서 열처리 가공에 의해 감소하였다. 열처리한 퀴노아의 수분흡수지수는 원곡보다 증가했지만 수분용해도지수는 감소하였다. 퀴노아의 in vitro 전분 가수분해율은 원곡보다 열처리한 퀴노아에서 크게 증가하였다. 퀴노아의 DPPH 라디칼 소거능과 아질산염 소거능은 가열처리에 의해 감소하는 경향이었는데 열탕 처리에서 가장 낮게 나타났으며, 이는 열처리 가공방법에 따른 항산화 물질 손실의 차이로 인한 결과로 판단되었다. 퀴노아를 열처리 가공 시에는 조리수에 의한 영양 생리활성 성분의 손실을 줄이는 방법으로 열처리 가공하는 것이 바람직한 것으로 제시되었다.