• 패션비즈니스
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• 제12권6호
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• pp.1-10
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• 2008

Public interest in healthy hairs gets growing as damaged hairs are seen more frequently with the generalization of heat permanent waves. For this study, experiments have been conducted to understand the influences on the changes in physical and morphological features of wave forms and damaged hairs, by collecting virgin hairs from the women in their mid-20's, who had not experienced chemical applications, and by dividing the applications of heat perm hair treatments, PPT(for pre-treatment) and LPP(for post-treatment), into the pre-treatment, the post-treatment, the pre & post-treatment, and the non-treatment. For the wave formations, curl waves were investigated by the bare eyes using the pictures taken by a digital camera. For the comparison of physical features, the experiments of tensile strength and elongation were done and their mean values were found. For the observations of morphological features, the pictures were taken by SEM for comparison. As for the findings, regarding the curl wave shapes of hairs, the most even and elastic S curl was formed in the case of non-treatment. In the physical features, both of the tensile strength and elongation showed a decreasing tendency in line with the hair damage levels, and the case of the pre & post-treatment indicated the tendency most similar to the control group. In the morphological features of the cuticle, observed with an SEM, the pre-treatment showed the higher possibility of reducing the cuticle damages than the post-treatment did. LPP was found to play the role of protective membrane for the post-treatment, and the pre & post-treatment turned out to reduce most effectively the cuticle damages.

• 열처리공학회지
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• 제30권2호
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• pp.67-73
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• 2017

Transformation behavior and hardness change were studied in five kinds of self-control steels; standard, high V, modified Ni, W, and high C-Ni steels. In the cooling rates of $10-100^{\circ}C/min$, the primary ferrite and bainite were formed, and the amount of the former increased with decreasing cooling rate. The bainite transformation temperature, Bs, was measured as 570, 560, 590, 575, and $565^{\circ}C$ in experimental steels, respectively, which was similar to the calculated temperature. The self-control, that is, the consistency in hardness, was observed, in which the hardness increased with the decrease in Bs. In the case of hot compression testing, the lower temperature deformation led to the enhancement in hardness.

• Preventive Nutrition and Food Science
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• 제7권1호
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• pp.48-51
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• 2002

In order to study the reaction behavior of bovine holo- and apo-$\alpha$-lactalbumin ($\alpha$-La) during heat treatment at 65~10$0^{\circ}C$, the samples were analysed by first (ID)-and second-dimensional (2D) native-polyacrylamide gel electrophoresis (Native-PAGE) and sodium dodecylsulfate (SDS)-PAGE. When bolo-$\alpha$-La or apo- $\alpha$ -La were heated, they formed non-native, monomers, dimers and trimers. The apo-$\alpha$-La was more heat-sensitive than holo-$\alpha$-La. The monomers seemed to have the same composition as the native $\alpha$-La, but many of the disulfide bonds could be non-native.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.400-403
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• 2004

A non-heat기leafed steel does not need quenching and tempering processes that are called a heat treatment differently from conventional steel. Since the tensile strength of this steel is higher than 900MPa, a conventional forming process should be changed to incremental forming process such as a cross wedge rolling that requires lower load capacity than conventional ones. In this paper, the cold cross wedge rolling (CWR) die has been designed using CAD/CAE In order to produce near-net-shaped component of ball stud of non-heat-treated cold steel. Finite element analyses were applied in order to investigate process parameters of CWR. Results provide that the stretching angle and the forming angie at knifing zone in CWR process is important parameter to be the stable process under the low friction coefficient condition.

• 열처리공학회지
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• 제19권4호
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• pp.225-229
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• 2006

TiAlN coatings are available in various industry fields as a wear resistant coating for high-speed machining, due to its high hardness, excellent oxidation and corrosion resistance. The corrosion resistance of TiAlN multilayer coatings is better than that of single TiN coatings. Most of TiAlN coated layers were formed by heat treatment of coating layers with a non-stoichiometric $Ti_xAl_{1-x}N$. In this study, TiAlN coated layer was prepared by R.F magnetron sputtering and investigated the thermal behavior for heat treatment at various temperature in tube furnace. The formation of large particles with porous microstructure and phase change from HCP to FCC were observed on coated layer during heat treatment over $850^{\circ}C$ and it reduced the corrosion resistance of coated TiAlN layers.

• 열처리공학회지
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• 제22권3호
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• pp.162-168
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• 2009

A horizontal tube furnace with a wide uniform-temperature zone was developed using isothermal characteristics of a heat pipe. The heat pipe heating system consists of a concentric annular shaped stainless-steel container, sodium as a working fluid and a screen mesh wick structure. The performance test of the heat pipe revealed that temperature changes along seven consecutive positions of the heat pipe outer wall were less than${\pm}0.1^{\circ}C$, thereby ensuring the high isothermal property. The isothermal property of the heat pipe-adapted tube fumace was investigated and compared to a conventional non-heat pipe type tube furnace. The temperature distribution measurement showed that the uniform temperature zone, in which temperature change is less than${\pm}$1$^{\circ}$C, of the heat pipe employed tube furnace system was about three times longer compared to the conventional tube furnace system.

• 한국식품저장유통학회지
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• 제12권6호
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• pp.552-557
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• 2005

열처리가 절단 감자의 품질에 미치는 영향을 조사하고자, 원형감자를 건열 및 습열처리하거나, 박피절단한 후 습열처리 하였다. 감자의 열처리조건은 원형감자의 경우 각각 $45^{\circ}C$에서 60분이었으며, 절단후 열처리한 감자의 경우$55^{\circ}C$의 열수에 45초간 침지하였다. 각각 열처리하여 제조된 감자절편은 표면의 물기를 제거한 다음, 필름봉지(LDPE, $30{\mu}m$, 15 cm x 20 cm)에 약 200 g씩 포장하여 $5^{\circ}C$에 저장하면서 품질변화를 조사하였다. 열처리는 전반적으로 호흡률을 저하시켰으며, hunter L값의 변화도 대조구에 비하여 낮았다. 건열처리는 대조구에 비하여 호흡률이 $20\%$ 정도 낮았으며, hunter L값은 다른 처리구와 비교하여 가장 높은 값을 유지하였다. 경도와 유리형 페놀화합물 함량의 변화는 시료구간 유의적인 차이를 나타내지 않았다. Vitamin C 함량은 대조구가 처리 직후 가장 높았으나, 그 감소율은 절단 후 열처리한 구가 대조구보다 낮았다. 관능적 품질 면에서 경도와 냄새는 처리구간에 유의적인 차이를 나타내지 않았지만, 표면색에 있어서 열처리구가 대조구에 비하여 유의적으로 우수한 것으로 나타내었으며, 특히 CH구에서 가장 우수하였다. 결과적으로 열처리는 감자 절단면의 갈변발생을 억제시켜 품질유지에 효과가 있는 것으로 나타나고 있으며, 절단 후 열처리(CH)가 보다 효과적이었다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1993년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.3-3
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• 1993

In mechanical testing of W-Ni-Pe heavy alloys, the cracks nucleate at W/W interface and propagate through W/ Imatrix interface or through matrix phase together with the cleavage of W grains. The mechanical properties can therefore be improved by control of the interfacial strength and area. In this presentation, some experimental result and techniques on this subject will be reviewed and discussed. The hydrogen embrittlement caused by the hydrogen segregation at interfaces during sintering in an hydrogen atmosphere can be removed by an heat-treattnent in vacuum or in an inert atmosphere. The heat-treatment condition can be estimated by using a diffusion equation for a cylindrical shape. The mechanical properties, in particular the impact property, are degraded by the segregation of non-metallic impurities, such as Sand P. The degradation can be prevented by adding a fourth element, such as La or Ca, active with the non-metallic impurities. The cyclic heat-treatment at usual heat-treattnent tempemture causes the penetration of matrix between W/W grain boundaries and results in remarkable increase in impact energy. This is due to an increase in the area of ductile failure during the impact test. The instability of W/matrix interface casued by addition of Mo or Re can be controlled by using W powders of different size. The increase in the interfacial area in found to be related to the presence of non-equilibrium pure W gmins among W(Mo or Re) solid solution gmins.

• 동력기계공학회지
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• 제2권3호
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• pp.49-54
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• 1998

This paper is investigated of hardness and adhesiveness of plasma sprayed coating steels by AE(Acoustic Emission) testing when loading a tensile. AE Parameters used are Event, Count, Energy and Amplitude. Test specimens are carbon steel(S45C) with sprayed coating layers of Ni-4.5wt.%Al(bond coating) and $TiO_2$(top coating), and carry out heat treatment at $800^{\circ}C\;and\;1000^{\circ}C$, respectively. The micro-hardness of the heat treatment specimen have been improved more than that of non-heat treatment. On the tensile test, the process and occurence of the exfoliation of the sprayed coating layer can be estimated by AE Characteristics of AE parameters, such as event, count, amplitude and energy, on the layer exfoliation are shown the similar aspects. The exfoliation of bond coating occure at about 20% of strain and top coating is about 5% of strain.

• Journal of Advanced Marine Engineering and Technology
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• 제23권6호
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• pp.806-813
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• 1999

The effect of Post-Weld Heat Treatment(PWHT) of SS400 Steel was investigated with parameters such as micro vickers hardness corrosion potential polarization behaviors galvanic current Al anode generating current Al anode weight loss etc. Hardness of each parts(HAZ, BM, WM)by PWHT is lower than that of each parts by Non Post-Weld Heat Treatment(NPWHT) However hardness of WM of HAZ part was the highest among those three parts and HAZ area were also acted as cathode without any case of heat treatment. Potential difference between each three parts by PWHT was also smaller compared to NPWHT. Therefore it is suggested that Corrosion resistance property is increased by PWHT. However both Al anode generating current and anode weight loss was also decreased by PWHT compared to NPWHT when SS400 steel is cathodically protected by Al anode.