• 동력기계공학회지
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• 제17권4호
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• pp.103-108
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• 2013

This study was investigated the effect of austenitizing treatment the microstructure and mechanical properties in modified 440A steel, and the results were as follows. The amount of remaining carbide decreases with increasing the austenitizing treatment temperature, and all carbide is completely dissolved at $1250^{\circ}C$. The amount of remaining carbide decreases with increasing the austenitizing treatment time, but the carbide remains insoluble up to 120 minutes at $1050^{\circ}C$. The strength and hardness gradually decrease with increasing the austenitizing treatment temperature and is significantly lower at $1250^{\circ}C$, while the elongation and the impact value rapidly increase. The strength and hardness rapidly decrease, the elongation and impact value rapidly insrease with increasing the austenitizing treatment time and exhibit no change at above 120 minutes. The austenitizing treatment modified 440A steel is required for temperature of above $1050^{\circ}C$ and time of above 60 minutes.

• 산업식품공학
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• 제14권1호
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• pp.60-64
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• 2010

Freeze-dried broccoli powder was incorporated into cookie dough at 5 levels (0, 1, 2, 3, and 4%, w/w) by replacing equivalent amount of wheat flour of the cookie dough. After aging and sheeting, cookies were baked at 170${^{\circ}C}$ for 8 min in an oven. The baked cookies were cooled to room temperature for 1 hr and packed in airtight bags prior to all measurements. The pH and moisture content were ranged 6.74-6.90 and 2.67-4.12% (wet basis) depending on the broccoli powder level, respectively. Lightness (L$^{\ast}$-value), redness (a$^{\ast}$-value), and hardness decreased while yellowness (b$^{\ast}$-value) increased significantly as the broccoli powder content increased (p<0.05). Spread factor of the control was significantly lower than that of samples containing broccoli powder regardless of the concentration (p<0.05) and increased significantly with increase in broccoli powder content (p<0.05). The broccoli concentration correlated significantly with most of properties except for pH and spread factor (p<0.05 or p<0.01). Hardness correlated negatively with moisture content (p<0.05) but correlated positively with spread factor (p<0.01).

• 한국식품영양과학회지
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• 제38권10호
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• pp.1430-1437
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• 2009

다시마를 Vibrio sp.로 분해하여 제조한 SCD로 기능성 빵을 만들기 위하여 mixture design을 이용한 원료의 최적 배합 비율을 구하였다. 다시마 SCD 빵의 max weight, strength, hardness 및 비용적의 값은 밀가루와 물의 첨가량이 증가할수록 감소하는 반면, SCD의 첨가량이 증가할수록 증가하였다. 밀가루와 물의 첨가량이 증가할수록 SCD의 첨가량이 감소할수록 발효팽창력의 값은 증가하였다. 밀가루의 첨가량이 증가할수록 SCD의 첨가량이 감소할수록 SCD 빵의 L(명도) 값과 b(황색도) 값은 증가하였으며, 밀가루와 물의 첨가량이 증가할수록 SCD의 첨가량이 감소할수록 다시마 SCD 빵의 a(적색도) 값은 감소하였다. ANOVA 분석에 의한 다시마 SCD 빵의 max weight, strength, hardness, 비용적, 색도 b(황색도) 값 및 수분흡착력은 linear model이 결정되었으며, distance, 발효팽창력, 색도 L(명도) 및 a(적색도) 값은 nonlinear model(quadratic model)이 선정되었다. Constraint coefficient 값의 분석 결과 SCD는 SCD 빵의 texture에 가장 큰 영향을 주었으며, 물은 발효팽창력, 비용적 및 수분흡착력에 가장 큰 영향을 미쳤다. 또한 밀가루는 SCD 빵의 색도에 가장 큰 영향을 미쳤다. Distance에서는 flour-SCD 및 water-SCD 상호작용이 있었으며, 발효팽창력에서는 flour-SCD 상호작용이 있었다. 또한 SCD 빵 색도의 L(명도)에서는 flour-SCD의 상호작용이 나타났으며, a (적색도)에서는 flour-SCD 및 water-SCD 상호작용이 있었다. Mixture(modified distance) design에 의해 결정된 다시마 SCD 빵의 밀가루, 물 및 SCD의 최적 배합비율은 각각 48.25, 30.89 및 3.86%이었다. 관능검사 결과 전해수로 처리한 SCD 빵은 시중제품보다 모든 면에서 품질이 낮았으나, 전해수 처리 SCD 빵은 대조구(전해수 미처리)보다 월등히 높은 점수를 받아 전해수로 처리된 SCD 빵의 맛, 조직감 및 향을 개선한다면 SCD의 산업화가 가능할거라 판단된다.

• 한국식품영양학회지
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• 제33권5호
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• pp.588-597
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• 2020

This study was conducted to secure basic information for corn processing by comparing the quality characteristics according to maize cultivars and kernel types (dent, intermediate, flint-like). As a result of analyzing 15 cultivars, a range of measurements were observed: 100-kernel weight, 22.89~35.63 g; moisture, 7.57~8.42%; crude protein, 8.46~11.45%; crude lipids, 3.26~4.83%; Hunter's L-value, 83.70~86.79; a-value, 2.61~5.49; b-value, 22.01~28.15; and total carotenoids, 6.74~17.07 ㎍/g. Significance among the cultivars was shown in all quality characteristics (p<0.001), but the significance among the kernel types was found only in crude protein (p<0.005), crude fat (p<0.001), and Hunter's L-value (p<0.05). The hardness of maize was decreased proportionally to the soaking time for all maize cultivars (p<0.001). In particular, with the same soaking time for different kernel types, the hardness difference was shown in the order of flint-like > dent ≒ intermediate. It was confirmed that the decrease in the hardness of flint-like kernel of close to that of hard-type starch was slowed compare dent and intermediate kernels. So it is expected the some characteristic of kernel types will contribute to the appropriate customized use of the developed cultivars.

• Corrosion Science and Technology
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• 제7권2호
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• pp.134-137
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• 2008

Cold arc welding of cast iron has been widely used with repair welding of metal structures. However its welding is often resulted in the galvanic corrosion between weld metal zone and heat affected zone(HAZ) due to increasing of hardness. In this study, corrosion properties such as hardness, corrosion potential, surface microstructures, and variation of corrosion current density of welding zone with parameters of used electrodes for cast iron welding were investigated with an electrochemical evaluation. Hardness of HAZ showed the highest value compared to other welding zone regardless of kinds of used electrodes for cast iron welding. And its corrosion potential was also shifted to more negative direction than other welding zone. In addition, corrosion current density of WM in polarization curves was qualitatively smaller than that of HAZ. Therefore galvanic corrosion may be apparently observed at HAZ. However galvanic corrosion may be somewhat controlled by using an optimum welding electrode.

• 대한가정학회지
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• 제44권3호
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• pp.163-169
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• 2006

The effects of adding Angelica plant (Bakluncho) and Angelica gigas (Senggumcho) powders on the quality characteristics of bread were investigated. The moisture, crude protein, ash, reducing sugar and vitamin C contents of Angelica plant (Bakluncho) powder were 7.78%, 6.07%, 7.37%, 6.13% and 50.10mg%, respectively, and of Angelica gigas (Senggumcho) powder were 8.69%, 12.28%, 5.15%, 2.21% and 108.00mg%, respectively. The lightness value decreased but the redness and yellowness values increased with the addition of Angelica plant (Bakluncho) and Angelica gigas (Senggumcho) powders. The mechanical hardness of bread decreased with the addition of 3% of Angelica plant (Bakluncho) powder, but increased with the addition of 1% and 5% of Angelica plant (Bakluncho) powder. The mechanical hardness of bread decreased with the addition of 1%, 3% and 5% of Angelica gigas (Senggumcho) powder. In sensory characteristics, the crust color, crumb color, moistness and springiness decreased, but aroma and hardness increased with the addition of Angelica plant (Bakluncho) and Angelica gigas (Senggumcho) powders. The savory taste and overall quality of breads with 1% Angelica plant (Bakluncho) and 1% Angelica gigas (Senggumcho) powders were higher than without either powder. A negative correlation was observed between mechanical hardness and overall bread quality with the addition of Angelica plant (Bakluncho) powder, while a positive correlation (p<0.01) was observed with the addition of Angelica gigas (Senggumcho) powder.

• 한국재료학회지
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• 제25권9호
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• pp.468-474
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• 2015

Evaluations of the microstructure and mechanical properties of age hardenable Cu-2.0wt%Be alloy are performed in order to determine whether it can be used as a welding electrode for projection welding. The microstructure examinations, hardness measurements, and tensile tests of selective aging conditions are conducted. The results indicate that the aging treatment with the fine-grained microstructure exhibits better hardness and high tensile properties than those of the coarse-grained microstructure. The highest hardness value and high tensile strength are obtained from the aged condition of $300^{\circ}C$ for 360 min due to the presence of the metastable ${\dot{\gamma}}$ precipitates on the grain boundaries. The values of the highest hardness and tensile strength are measured as 374 Hv and 1236.2 MPa, respectively. The metastable ${\dot{\gamma}}$ precipitates are transferred to the equilibrium ${\gamma}$ precipitates due to the over-aged treatment. The presence of the ${\gamma}$ precipitates appears as nodule-like precipitates decorated around the grain boundaries. The welding electrode with the best aging treated condition exhibits better welding performance for electrodes than those of electrodes used previously.

• 대한치과기공학회지
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• 제31권3호
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• pp.9-14
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• 2009

This study evaluated the mechanical properties of Ti-Cu alloys with the hope of developing an alloy for dental casting with better mechanical properties than unalloyed titanium. Ti-Cu alloys with four concentrations of Cu(2,5,10wt%) were made in an argon-arc melting furnace. The microstructure and micro-Vickers hardness were determined. X-ray diffraction pattern test was performed on the polished specimens. The microstructure of 2%Cu and 5%Cu alloys are shown acicular ${\alpha}Ti$ phase formed on the surfaces of previously formed $\beta$grains. The 10%Cu alloys has essentially a eutectoid structure; this structure includes lamella of ${\alpha}Ti$ and $Ti_2Cu$ phase that transformed from ${\alpha}Ti$ at the eutectoid temperature. The micro-Vickers hardness of CP Ti specimens was significantly(p<0.05) lower than that of any of the other alloys. Among the Ti-Cu alloys, the 10%Cu alloys exhibited a significantly(p<0.05) higher hardness value. but lower than that of Ti-6%Al-4%V alloy. From these results, it was concluded that new alloys for dental castings should be designed as Ti-Cu based alloys if other properties necessary for dental castings were obtained.

• Preventive Nutrition and Food Science
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• 제16권1호
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• pp.62-66
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• 2011

Functional foods play an important role in daily diet, human health and the food industry. Hemp was reported to have many advantages for nutritional and medicinal usage. In this study, extruded hemp-rice (EHR) flour, containing 30% hemp, was mixed with the wheat flour to create bread loaves at the concentrations of 5, 10 and 15%. Bread made from 100% wheat flour (with no added EHR flour) was used as a control. The physical parameters, including expansion ratio, specific volume and crust/crumb color were evaluated separately. In addition, changes in hardness of the bread during storage at ambient temperature for 3 days were also studied. The results showed that 10%-EHR bread exhibited the highest hardness value, while 15%-EHR bread presented the lowest. The bread containing EHR flour had lower specific volume and bigger air cells compared to the control. Moreover, the crust and crumb color of EHR-containing bread was significantly darker than those of the control. In this study, the 15%-EHR bread showed higher specific volume, lower hardness and bigger air cell structures.

• 한국식품영양학회지
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• 제19권4호
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• pp.473-481
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• 2006

This study was carried out to investigate the properties of cucumber kimchi prepared with different minor ingredients(potato, puchu). Acidity, pH, color value, hardness, and lactic acid bacteria were measured under the condition of $10^{\circ}C$ for 25 days. Five conditions of making cucumber kimchi included: cucumber kimchi with puchu 300g(treatment 1, control), cucumber kimchi with potato 90g, puchu 210 g(treatment 2, 5-1), cucumber kimchi with potato 150g, puchu 150 g(treatment 3, S-2), cucumber kimchi with potato 210g, puchu 90 g(treatment 4, S-3), cucumber kimchi with potato 270g, puchu 30g(treatment 5, S-4). Hardness of cucumber kimchi appeared higher values as the potatoe's volume increased(S-1, S-2, S-3, S-4), during all fermentation days. The results showed very significant values in pH(p<0.001), acidity(p<0.001), 'L' of lightness(p<0.05), hardness(p<0.001), lactic acid bacteria(p<0.001) according to fermentation. And the results showed very significant values in 'a' of redness(p<0.01), hardness(p<0.001) according to cucumber kimchi samples. These results showed that fermentation patterns of cucumber kimchi were influenced by the different minor ingredients used.