• Restorative Dentistry and Endodontics
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• 제46권1호
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• pp.6.1-6.10
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• 2021

Objectives: The aim of this study was to evaluate the corrosion resistance of heat-treated (Reciproc and WaveOne) and non-heat-treated (ProTaper and Mtwo) superelastic nickel-titanium endodontic files when immersed in a 5.25% sodium hypochlorite solution. Materials and Methods: Anodic polarization curves were obtained with potential sweeps that began at the open circuit potential or corrosion potential (E_corr). The pitting potential (E_pit) was identified on the anodic polarization curve as the potential at which a sudden increase in current was observed. The micromorphology of the 28 tested files was analyzed before and after the electrochemical assay using scanning electron microscope (SEM). The data were analyzed using 1-way analysis of variance with the post hoc Bonferroni test (for E_corr) and the Student t-test for independent samples (for E_pit). Results: The mean E_corr values were 0.506 V for ProTaper, 0.348 V for Mtwo, 0.542 V for Reciproc, and 0.321 V for WaveOne files. Only WaveOne and Protaper files exhibited pitting corrosion, with E_pit values of 0.879 V and 0.904 V, respectively. On the SEM images of the ProTaper and WaveOne files, cavities suggestive of pitting corrosion were detected. Conclusions: Signs of corrosion were observed in both heat-treated and non-heat-treated files. Of the evaluated files, WaveOne (a heat-treated file) and ProTaper (a non-heat-treated file) exhibited the lowest corrosion resistance.

• 대한전기학회논문지:전력기술부문A
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• 제48권12호
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• pp.1544-1553
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• 1999

Recently, ultrasonic testing techniques have been widely used in the evaluation of the quality of metal. In this experiment, six heat-treated temperature of specimen have been considered : 0, 1200, 1250, 1300, 1350 and 1387$^{\circ}C$. As heat-treated temperature increases, the grain size of stainless steel also increases and then, eventually make it destroy. In this paper, a pattern recognition method is proposed to identify the heat-treated temperature of metals by evidence accumulation based on artificial intelligence with multiple feature parameters; difference absolute mean value(DAMV), variance(VAR), mean frequency(MEANF), auto regressive model coefficient(ARC), linear cepstrum coefficient(LCC) and adaptive cepstrum vector(ACV). The grain signal pattern recognition is carried out through the evidence accumulation procedure using the distances measured with reference parameters. Especially ACV is superior to the other parameters. The results (96% successful pattern classification) are presented to support the feasibility of the suggested approach for ultrasonic grain signal pattern recognition.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.40-43
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• 2009

This study is for investigating the effect of induction heating with various alloy elements to manufacture the pre-heat treated steels of 100kgf/$mm^2$ for cold heading. For four kinds of steels, the condition of induction heating (especially, induction tempering) were observed, and their microstructure and tensile and compressive properties were investigated. The middle carbon steel and the low carbon Cr-Mo steel are needed the higher Grange-Baughman tempering parameter than that of the low carbon Cr steel to obtain 100kgf/$mm^2$ tensile strength. For accomplishing the pre-heat treated steel of 100kgf/$mm^2$ tensile strength having advanced cold heading. It is needed that the pre-heat treated steel is manufactured by induction quenching and tempering with the low carbon alloy steel to have the high ratio of ferrite and the fine globular cementite simultaneously.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.771-772
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• 2009

• 대한조선학회지
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• 제10권2호
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• pp.9-18
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• 1973

The effects of carburization on the fatigue strength and cracks were studied. The fatigue phenomena of the carburized specimens were compared with noncarburized specimens those were either heat-treated or un-treated. The fatigue strength of these specimens were measured by rotating bending fatigue machine. The obtained results indicated that the fatigue strength of carburized specimens were increased ranging from 24-59 % than those of un-treated, and 22-38% than those of heat-treated. The Vickers hardness of carburized were also increased as much as 138-195% than those of un-treated, and 42-125% than those of heat-treated. The microscopic observation of the carburized specimens mostly composed of minute pearlitic structure at hard case exhibited to have more localized slip than those of non-carburized specimens.

• 자연과학논문집
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• 제11권1호
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• pp.151-157
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• 1999

승화성이 우수한 분산염료를 사용하여 면포에 대한 열 전사 염색성의 최적조건을 알아보기 위하여 온도, 시간, 농도에 따른 전사 염색에 대하여 연구하였다. 이 최적조건에 따라 팽윤제를 첨가한 후의 열 전사 염색성과 전 처리된 면포의 열 전사 염색성 및 분자량에 따른 열 전사 염색성을 검토하였으며, 세탁견뢰도와 일광견뢰도를 측정하여 열 전사날염에 대한 염색견뢰도를 측정하였다. 분산염료를 사용하여 면포에 대한 열 전사날염의 최적조건은 염료용액의 농도는 5%로, 처리온도가 $200^{\circ}C$, 처리시간은 3분에서 열 전사 염색성이 우수하였다. 면포에 대한 전처리의 시간이 길어질수록 열 전사 염색성이 향상되었으며, 팽윤제로는 Glycerin이 우수하였고, 혼합처리보다는 전처리가 열 전사 염색성이 우수하였다. 분자량에 따른 열 전사 염색성은 혼합처리의 경우 분자량이 작을수록 열 전사 염색성이 향상되었으며, 분자량이 커짐에 따라 열 전사 염색성이 나빠짐을 나타내었다. 그러나 전처리의 경우는 분자량에 큰 영향을 받지 않음을 나타내었다. 열 전사 날염된 면포의 세탁견뢰도는 염료의 분자량이 작은 것이 우수하였고, 일광견뢰도는 염료의 분자량이 큰 것이 보다 우수한 견뢰성을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제42권1호
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• pp.13-19
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• 2014

국내의 주 생산 수종인 잣나무 $90{\times}90mm$ 각재의 적정한 열처리 조건을 찾기 위해 3가지 열처리 스케줄을 적용하여 재색과 물성에 미치는 영향을 연구하였다. 1차 열처리시 온도는 $170^{\circ}C$와 $190^{\circ}C$, 시간은 예비가열시간 1시간을 포함하여 9시간과 13시간을 적용하였다. 2차와 3차 열처리는 모든 공시 각재에 동일하게 $190^{\circ}C$-9시간을 적용하였다. 열처리 횟수가 증가할수록 백색도 $L^*$는 직선적으로 감소하였으며 표준편차도 감소하였다. 열처리 횟수가 증가할수록 색차 ${\Delta}E^*$는 직선적으로 증가하였으며, 표준편차가 커지는 경향이 있었다. 알려진 바와 달리 열처리 시편의 평균 종압축강도가 무처리 시편보다 9% 높았다. 항팽윤율과 중량증가율을 측정하여 열처리 시편의 치수안정성이 무처리보다 크게 증가하였음을 보였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.19-25
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• 2006

With particular regards to the hepatitis A virus (HAV), a terminal dry-heat treatment ($100^{\circ}C$ for 30 min) process, following lyophilization, was developed to improve the virus safety of a solvent/detergent-treated antihemophilic factor IX concentrate. The loss of factor IX activity during dry-heat treatment was of about 3%, as estimated by a clotting assay. No substantial changes were observed in the physical and biochemical characteristics of the dry-heat-treated factor IX compared with those of the factor IX before dry-heat treatment. The dry-heat-treated factor IX was stable for up to 24 months at $4^{\circ}C$, The dry-heat treatment after lyophilization was an effective process for inactivating viruses. The HAV and murine encephalomyocarditis virus (EMCV) were completely inactivated to below detectable levels within 10 min of the dry-heat treatment. Porcine parvovirus (PPV) and bovine herpes virus (BHV) were potentially sensitive to the treatment. The log reduction factors achieved during lyophilization and dry-heat treatment were ${\ge}5.60$ for HAV, ${\ge}6.08$ for EMCV, 2.64 for PPV, and 3.59 for BHV. These results indicate that dry-heat treatment improves the virus safety of factor IX concentrates, without destroying the activity. Moreover, the treatment represents an effective measure for the inactivation of non-lipid enveloped viruses, in particular HAV, which is resistant to solvent/detergent treatment.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.35-36
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• 2009

Development trend and current status were surveyed for pre-heat-treated high strength cold heading quality (CHQ) wire and it's forming technology. Spheroidizing, quenching, and tempering heat treatments are eliminated by adapting the pre-treated wire, which could reduce energy consumption rate and green house gas emission rate during produce parts requiring high strength. There are some challenging problems to expand application area such as enhancing forming tool life, and preventing delayed failure. Domestic research movement concerning the development and application of the new high strength wire was introduced.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.29-31
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• 2019

The ZTO/p-Si thin film was produced and investigated for tunneling phenomena caused by the interface characteristics of the depletion layer. ZTO thin film was deposited and heat treated to produce barrier potentials by the depletion layer. The negative resistance characteristics were shown in the thin film of ZTO heat treated at $100^{\circ}C$, and the insulation properties were the best. Current decreased in the negative voltage direction by nonlinear show key characteristics, and current decreased in tunneling phenomenon by negative resistance in the positive voltage direction. Heat treated at $100^{\circ}C$, the ZTO thin film has increased barrier potential in the areas of the depletion layer and therefore the current has increased rapidly. The current has decreased again as we go beyond the depletion layer. Therefore, tunneling can be seen to make insulation better. In the ZTO thin film heat treated at $70^{\circ}C$ without tunneling, leakage current occurred as current increased at positive voltage. Therefore, tunneling effects by negative resistance were found to enhance insulation properties electrically.