• Journal of the Korean Ceramic Society
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• v.47 no.5
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• pp.474-478
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• 2010

We studied the energy barrier for proton conduction with volume variation in $BaZrO_3$ using a first principles study to investigate an optimum volume for the proton conduction. The volume increase of $BaZrO_3$ was expected to decrease the energy barrier for proton rotation and to increase that for proton transfer, and these trends could be extrapolated when the volume was decreased. However, the energy barriers for the proton transfer with the volume decrease were increased, while all the other energy barriers varied as expected. We could explain this unexpected behavior by the bent Zr-O-Zr structure, when the volume was decreased.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.759-766
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• 2004

The addition of steel fiber with concrete significantly improves the engineering properties of structural members, notably shear strength. The purpose of this study is to determine the steel fiber shape, aspect ratio and volume fraction ratio in a point of practical usage as structural members. Steel fiber factor and volume fraction are also considered to verify the strengthening effect in member level. From the reviewing of previous researches and analyzing of consecutive material test results, the optimum shape and length of steel fiber, which can have a good strengthening effects were defined as a hooked end type and larger than 1.5 times of maximum gravel size. Analyzing the test results of strength and deformation capacity, aspect ratio 75 and volume fraction $1.5\%$ can be having a maximum strengthening effect of steel fiber. Also steel fiber factor, tensile splitting strength, and flexural strength are found as key parameter in shear strengthening effect in member level.

• Journal of Internet Computing and Services
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• v.12 no.5
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• pp.159-170
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• 2011

In procurement auctions, auction frequency and transaction volume per auction have been analyzed as important factors in determining auction performance. However, there is no empirical study on the effect of auction frequency and transaction volume in procurement auction. Current studies mainly focus on bidder behavior analysis and new system design in procurement auction. In the study, we analyze the effect of two factors on relative winning price empirically by using real auction data from MRO procurement outsourcing company in Korea. From the results, we find the winning price is lower when the frequency of auction with same item category is lower. The low frequency of auctions means participating bidders have limited information of previous auctions and they bid their best price to win the current auction due to less opportunity of reopening the auction in near future. The larger purchase amounts of MRO items didn’t results in lower winning price, contrary to our hypothesis. The possible reason is that the price of MRO items already reflects the economy of scales and the increased volume per auction do not cause the further discount of MRO items from the auction.

• Archives of Plastic Surgery
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• v.48 no.6
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• pp.583-589
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• 2021

Background In prosthesis-based breast reconstruction patients, the drain tends to be kept in place longer than in patients who undergo only mastectomy. Postoperative arm exercise also increases the drainage volume. However, to preserve shoulder function, early exercise is recommended. In this study, we investigated the effect of early exercise on the total drainage volume and drain duration in these patients. Methods We designed a prospective randomized trial involving 56 patients who underwent immediate breast reconstruction following mastectomy using tissue expanders. In each group, the patients were randomized either to perform early arm exercises using specific shoulder movement guidelines 2 days after surgery or to restrict arm movement above the shoulder height until drain removal. The drain duration and the total amount of drainage were the primary endpoints. Results There were no significant differences in age, height, weight, body mass index, or mastectomy specimen weight between the two groups. The total amount of drainage was 1,497 mL in the early exercise group and 1,336 mL in the exercise restriction group. The duration until complete removal of the drains was 19.71 days in the early exercise group and 17.11 days in the exercise restriction group. Conclusions Exercise restriction after breast reconstruction did not lead to a significant difference in the drainage volume or the average time until drain removal. Thus, early exercise is recommended for improved shoulder mobility postoperatively. More long-term studies are needed to determine the effect of early exercise on shoulder mobility in prosthesis-based breast reconstruction patients.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1789-1793
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• 2008

The Oxygen Index was measured for another flame retardant APP, or phosphorus, and other flame retarding assistants ZS, ZHS, AOM, and ZB, which are used as low smoke emitting materials, in order to see the increase in the flame retardation effect in comparison to the volume of additions. The results show that their flame retardation synergy effect was very small compared to the main flame retardants. The mixed use of main flame retardants, low smoking emitting materials, and phosphorus is a very important area of examination for creating synergy effect of flame retardation and lowering smoking and toxicity. For this, the results of flame retardation effect in comparison to the volume of addition of each low smoke emitting material are shown below.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.6
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• pp.38-47
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• 1989

The Finite Element Method has been employed to calculate the effect of particle size, matrix, and volume fractions on the stress-strain relations of .alpha.-.betha. titanium alloys. It was found that for a given volume fraction, the calculated stress-strain curve was higher for a finer particle size than for a coarse particle size within the range of the strains considered, and this behavior was seen for all the different volume fraction alloys considered. The calculated stress-strain curves for three vol. pct .alpha. alloys were compared with their corresponding experimental curve, and in general, good agreement was found.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.508-510
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• 1987

The variation electrical resistivity of Carbon black filled polymers with volume percent of carbon black was investigated. The relationships between the surface tension of polymer and dispertion effect of carbon black were studied to find the steep drop of electrical resistivity. The critical volume percent of carbon black increased with the increasing surface tension of polymer. The PTC intensity decreased with the increasing volume percent of carbon black.

• Journal of the Ergonomics Society of Korea
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• v.7 no.2
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• pp.15-21
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• 1988

Changes of the surface area and the volume of limb are important factors for designing clothes and shoes. The limb volume increases slightly in the afternoon in general, because of human activity, as a diurnal variation. Changes are also associated with menstrual cycle, pregnancy, physical exercise and environmental temperature. The most effective method for measuring the surface area of limb is the paper replacement method.

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.65-69
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• 2000

This study is to investigate the characteristics of fatigue crack propagation in rolled super duplex stainless steel that was changed austenite-ferrite volume fraction by heat treatment. It was used two kinds of specimen the rolling and the transverse directions δ-phase fraction affected sound velocity hardness and Young's modulus. Characteristics of fatigue crack propagation was affected by anisotropy and (δ+γ) phase volume fractions.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.666-669
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• 1993

The space charge fields, including intermode apace charge fields in photorefractive material with two impurities are obtained for the small light intensity at large modulation depth, and their implication of high-capacity volume holographic interconnection are presented. In the following data regions the effect of intermode space charge fields are suppresed and the criteria for optimal implementation of volume holographic interconnections are satisfied.