• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.1-20
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• 1998

Processing of thin films by chemical vapor deposition (CVD) is accompanied by chemical reactions, in which the rigorous kinetic analysis is difficult to achieve. In these conditions, thermodynamic calculation leads to better understanding of the CVD process and helps to optimise the experimental parameters to obtain a desired product. A CVD phase diagram has been used as guide lines for the process. By determining the effect of each process variable on the driving force for deposition, the thermodynamic limit for the substrate temperature that diamond can deposit is calculated in the C-H system by assuming that the limit is defined by the CVD diamond phase diagram. The addition of iso-supersaturation ratio lines to the CVD phase diagram in the Si-Cl-H system provides additional information about the effects of CVD process variables.

• Transactions of Materials Processing
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• v.18 no.8
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• pp.596-600
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• 2009

Finite element simulation is an alternative method to practically find the forming limit diagram(FLD). In this paper, the novel fracture criterion is utilized to predict the FLD in conjunction with finite element analysis for sheet forming. The principal scheme of the fracture criterion in this paper is that growth of the micro voids leads up to fracture in the viewpoint of micro-mechanics. The numerical FLD is verified by results of the out-of plane stretching test using hemispherical punch. The verification is also conducted about two types of material. These results are in good accord with the experimental results. Especially, the proposed scheme is appropriate to predict FLDs for a restricted material with low ductility after the instability point or ultimate tensile strength.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.150-158
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• 1998

Limit dextrin of Korean beer(3 brands) and Japanese beer(21 brands) were separated by ethanol fractionation. Limit dextrin of Korean and Japanese beer was estimated to be 1.1%. 1H-NMR analysis revealed that the limit dextrin showed both signal of $\alpha$-1, 4- and $\alpha$-1, 6- glucosidic linkage with its estimation ratio of average 5.5:1. Limit dextrin was hydrolyzed to glucose with the yield of 57.22% by Aspergillus awamori $\alpha$-glucosidase(24.7 unit) plus human salivay $\alpha$-amylase(2.4 unit) in 100${mu}ell$ of 0.043M acetate buffer at 37$^{\circ}C$ for 5 hour. Among them, limit dextrin of Korean beer showed the highest hydrolysis rate of 76%. Small size sugars (64.8%) removed by ethanol fractionation and limit dextrin(21.4%) hydrolyzed by amylases that is digestable sugar. Non hydrolyzed limit dextrin(13.8%) by the amylases which can be a growth factor of Bifidobacterium in human intestine.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.788-792
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• 2010

The yttrium-barium-copper-oxide (YBCO) coated conductor, which supplement the fault of the existing superconducting current-limit materials YBCO thin film, bismuth-strontium-calcium-copper-oxide(BSCCO) wire and bulk, has been improved its mechanical weakness and has high index; hence, after quench YBCO coated conductor could limit the fault current effectively because of fast resistance occurrence speed. Furthermore, it has wide applicable area as an current limit material because it shows different resistance occurrence tendency by the thickness and kind of stabilization material sputtered on the superconducting layer. Therefore, many researchers are carrying out the study of application of YBCO coated conductor to superconducting fault current limiter (SFCL) for making high quality current limit element, based on resistance type. On the other hand, the study for other type except resistance type has been rarely conducted for the application of YBCO coated conductor to SFCL as an current limit element. Consequently, in this study, YBCO coated conductor with different stabilization layer Cu and Stainless steel, is applied to SFCL using iron core and coil, and examine the many index points as an current limit element, such as current limit characteristic, the tendency of resistance occurrence, response time, the temperature trend for stability.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1097-1103
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• 1988

This paper deals with surface crack behavior and the fatigue life prediction of notched specimens using the relation between surface crack length, a, and the cycle ratio, $N/N_{f}$. From the $a-N\;/\;N_{f}$ curves, UC(the upper limit curve), LC(the lower limit curve) and MC(the middle limit curve) were assumed and utilized to predict the fatigue life and crack growth rate. The data computed from the three assumed curves were compared with the experimental data. It has been found that in the stable crack growth region ($N/N_{f}=0.3-0.8$) fatigue life can be predicted within 20% errors. Using the characteristics of $a-N\;/\;N_{f}$ curve, it is possible to predict the $da/dN-K_{max}$ curve, the $da/dN-{\Delta}K_{{\varepsilon}_t}$ curve, and the $S-N_{f}$ curve.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.183-185
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• 2008

Forming Limit Diagram(FLD) is a representative tool for evaluating formability of sheet metals. This paper presents a methodology to determine the FLD using Finite Element Method. For predicting the forming limits numerically. Previous methods such as using the thickness strain or the ductile fracture criterion are limited at plane strain domain. These results suggest that behavior of the void growth in sheet metals is different from real one. In contrast to previous methods, a more exact model which takes void growth into account is used. This result agrees with the experimental result qualitatively.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.1
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• pp.3-9
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• 2002

In the field of design of mechanical structure and expectation of life time, characteristic of fatigue limit comes out to he the most important problem. In this paper, in order to get fatigue limit, (I) investigate the aspects of economy, time and confidence comparing two methods: the method by fracture probability introducing statistical conception and the staircase method. And (II) examine the experience approaching fatigue limit and coaxing effect. The value of fatigue limit by staircase method in very effective in view of practical use, and coaxing comes out by the same material effect as restraining crack progress, not as strengthening the tip of crack alone.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1-1
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• 2009

Recently, the FPD industry has faced the limit in market growth due to lack of new growth engine as a replacement of television. With sluggish market demand deepened by global economic crisis and persistent concern over panel oversupply, growth of the panel market has sharply slowed down, and profitability has been eroded. This also has tremendous effect on related industries including component, material and machine industries, spreading a sense of crisis across the whole FPD industry. Under this circumstance, for the FPD industry to take off once again, all involved in the FPD industry must cooperate and come up with innovative ideas, and identify the driving force to realize turbo-charged growth.

• Journal of Environmental Science International
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• v.32 no.2
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• pp.121-130
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• 2023

This study was conducted to investigate changes in seed vigor based on temperature of dry heat and duration treatment of watermelon seeds and examine the effect on percent of emergence and seedling vigor. When the upper limit temperature of dry heat treatment was raised to 80℃, the percent of the germination decreased. Moreover, T₅₀ was delayed as the upper limit temperature of dry heat treatment increased. The higher the upper limit temperature of dry heat treatment and the longer the treatment period, the higher the percentage of abnormal seedlings. The optimum upper limit temperature for dry heat treatment was 72℃, and the treatment period was five days. Seed vigor was better maintained at 30℃, 45℃, and 52℃, followed by stepwise exposure to high temperatures of 72℃, the upper limit of dry heat treatment, rather than dry heat treatment at a high temperature of 72℃ for 5 days from the initial stage of treatment. When the fungicide was added during the dry heat treatment process, the germination percentage decreased and the percent of the abnormal seedling percentage increased. However, the addition of 10 mg/kg fungicide did not significantly reduce seed vigor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.285-293
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• 2023

This study was conducted to determine the sowing limit period and predict growth in the northern region based on accumulative temperature for each growth stage of soybean cultivated in the southern regions of the Korean Peninsula. First, the results of a demonstration test in the central region (Yeoncheon) of the Korean Peninsula were very similar to the predicted and actual values on the date by growth stage obtained through cultivation. This method was then applied to seven agricultural climatic zones in the northern Korean Peninsula. The results predicted that regardless of ecotype, soybean could be grown and harvested in the southern and northern parts of Mt. Suyang, south of the East Sea, and in the central and northern inland areas. However, it was predicted that no ecotype could be grown and harvested normally in the northern alpine region. Furthermore, north of the East Sea, the prediction indicated that early and mid-maturing cultivars could be grown and harvested normally, but middle-late maturing cultivars appeared to lack the number of growth days. The sowing limit period also varied depending on the ecotype, although it was reached earlier as higher latitudes were approached; the period ranged from May 16 to June 26 in the northern and southern parts of Mt. Suyang, north and south of the East Sea, and central and northern inland areas. Furthermore, all ecotypes of the northern alpine region, as well as mid-late maturing cultivars in the north of the East Sea, were predicted to be unable to grow normally owing to the lack of number of days required for soybean growth and development.