• Title/Summary/Keyword: High Volume

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Effect of Volume Variation on Energy Barrier for Proton Conduction in BaZrO3 (BaZrO3의 부피 변화가 프로톤 전도 에너지 장벽에 미치는 영향)

  • Jeong, Yong-Chan;Kim, Dae-Hee;Kim, Byung-Kook;Kim, Yeong-Cheol
    • 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.

Comparison of PM 10 concentration between Gent Sampler and High-volume air sampler (Gent sampler와 High-volume air sampler의 분진 농도 비교연구)

  • 임종명;이현석;장미숙;이진홍
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2003.05b
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    • pp.275-276
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    • 2003
  • 산업의 발달에 따른 환경 오염물질의 증가와 오염물질의 종류가 다양화됨에 따라 대기 중의 유해원소 및 미량원소에 의한 환경오염과 그로 인한 인체건강에 대한 영향은 인간생활에 심각한 문제가 되므로 대기 중의 농도를 정확히 측정하는 것은 매우 중요한 일이다. 특히 미세 입자는 오염된 도심지역 분진수의 90∼99%에 이르는 높은 비율을 보이고 있고, 폐 깊숙이 침투하여 폐암을 비롯한 폐질환을 일으킬 수 있다. (중략)

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Steel Fiber Reinforcement for Shear Capacity Enhancement of High Strength RC Columns (고강도 RC 기둥의 전단능력 증진을 위한 강섬유 보강)

  • 장극관;이현호;문상덕
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.469-474
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    • 2002
  • This study was to define the strengthening effect of steel fibers in high strength RC columns. For this, ten specimens of columns were tested under cyclic lateral load and constant axial load. The testing parameters are steel fiber volume fraction of concrete and shear reinforcement ratio of hoop bars. Finally, the optimal content of steel fibers was evaluated as 1.0 - 1.5 % volume fraction of concrete.

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A Study On the Durability of High Volume Fly Ash Concrete (High Volume 플라이애시 콘크리트의 내구성 연구)

  • 조현수;김병진;이진용;이광명
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.455-460
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    • 2000
  • Fly ash can be used as cement replacement material and can also produce the durable concrete. According to the results, the compressive strength of concrete containing fly ash is slightly lower than that of normal concrete at early ages, however, the long-term compressive strength is significantly higher beyond 90 days, and it increases the durability of concrete as well.

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Durability Characteristics of Low Strength Fly ash-Cement Composites (저강도 플라이애시-시멘트 복합체의 내구특성)

  • 원종필;신유길;이용수;안태송
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.142-147
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    • 2000
  • Durability characteristics of controlled low strength material(flowable fill) with high volume fly ash content was examined. The mix proportions used for flowable fill are selected to obtain low-strength material in the 10 to 15kgf/㎥ range. The optimized flowable fill was consisted of 60kgf/㎥ cement content, 280kgf/㎥ fly ash content, 1400kgf/㎥sand content, and 320kgf/㎥water content. Subsequently, durability tests including permeability warm water immersion, repeated wetting & drying, freezing & thawing for high volume fly ash-flowable fill are conducted The test results indicated that flowable fill has has acceptable durability characteristics.

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Development of a Oil-Cooler for High-Speed CNC Lathe (고속 CNC선반용 공랭식 오일 냉각기 개발)

  • Yum, Man-Oh
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.4
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    • pp.11-16
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    • 2003
  • Recently, CNC lathe is in need of higher speed for precision works. So more intensive and compact heat exchanger is necessary to cool down the heat in short time from drills and works during high speed working. In this study, to increase heat transfer coefficient per unit volume, inner groove tube is designed and compact oil cooler, 57% volume of conventional type, is manufactured. The heat transfer performance is experimented and is compared with the performance of conventional type.

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A Study on the Application of Survival Analysis to Terminated Life Insurance Polices

  • Kang, Jung-Chul
    • Journal of the Korean Data and Information Science Society
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    • v.16 no.2
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    • pp.237-253
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    • 2005
  • In Korea, the volume of insurance industry has been increased rapidly with helping the economic growth, the increment of GNP and derive of public welfare policy. But the other side of the volume increment, the life insurers have some problems, such as the high rate of turnover, lapses and surrenders, in processing of acquiring more insurance contracts. The object of this paper is the analysis of the causes and properties of the high rate of turnover, lapses and surrenders using statistical survival model. Also we hope that the insurers will use the results of analysis to reduce the rates.

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A Longitudinal Study on Human Milk Volume and Lactational Pattern (수유 기간별 모유 분비량과 수유양식에 관한 연구)

  • 이종숙;김을상
    • Journal of Nutrition and Health
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    • v.24 no.1
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    • pp.48-57
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    • 1991
  • The longitudinal changes on human milk volume per day and lactational performance of Korean primiparae(n=9) and multiparae(n=6) from 0.5 month to 5 months after parturition have been studied by test-weighing method. The human milk volume per day tended to increase during lactation. The mean volume to the 3rd month of lactation was 643m1 for primiparae and 654m1 for multiparae, and it was 647 $\pm$ 182m1 for both of them. The mean volume to the 5th month of lactation was 648m1 for primiparae and 668m1 for multiparae, and it was 658$\pm$186$m\ell$ for both of them. The peak volume was observed at the 1st month of lactation in 8 women of 15 lactating women, that is, 53.3% . The high distributions of the individual mean volume to the 5th month were found 550~650$m\ell$(40.0% ) and 650~750$m\ell$(26.7% ). and 13 women of 15 lactating women(86.6% ) were observed below 750m1. The number of feeding per day was 7.7~9.3 to the 5th month and the mean volume per feeding was 65~101$m\ell$. While the former tended to decreased, the latter increased during lactation. The human milk volume was correlated with the peak volume. but not with maternal age. weight before delivery. maternal height and birth weight. As mentioned above, the human milk volume of Koreans was about 658$\pm$ 186$m\ell$ and 86.6% of it was below 750$m\ell$. So the human milk volume, referred to as 800$m\ell$ in recommended dietary allowances for Koreans might be estimated over real amount. It is necessary to study according to regions. socioeconomic levels. maternal nutritional status and the early stage of lactation.

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Characterization and predictive value of volume changes of extremity and pelvis soft tissue sarcomas during radiation therapy prior to definitive wide excision

  • Gui, Chengcheng;Morris, Carol D.;Meyer, Christian F.;Levin, Adam S.;Frassica, Deborah A.;Deville, Curtiland;Terezakis, Stephanie A.
    • Radiation Oncology Journal
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    • v.37 no.2
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    • pp.117-126
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    • 2019
  • Purpose: The purpose of this study was to characterize and evaluate the clinical significance of volume changes of soft tissue sarcomas during radiation therapy (RT), prior to definitive surgical resection. Materials and Methods: Patients with extremity or pelvis soft tissue sarcomas treated at our institution from 2013 to 2016 with RT prior to resection were identified retrospectively. Tumor volumes were measured using cone-beam computed tomography obtained daily during RT. Linear regression evaluated the linearity of volume changes. Kruskal-Wallis tests, Mann-Whitney U tests, and linear regression evaluated predictors of volume change. Logistic and Cox regression evaluated volume change as a predictor of resection margin status, histologic treatment response, and tumor recurrence. Results: Thirty-three patients were evaluated. Twenty-nine tumors were high grade. Prior to RT, median tumor volume was 189 mL (range, 7.2 to 4,885 mL). Sixteen tumors demonstrated significant linear volume changes during RT. Of these, 5 tumors increased and 11 decreased in volume. Myxoid liposarcoma (n = 5, 15%) predicted decreasing tumor volume (p = 0.0002). Sequential chemoradiation (n = 4, 12%) predicted increasing tumor volume (p = 0.008) and corresponded to longer times from diagnosis to RT (p = 0.01). Resection margins were positive in three cases. Five patients experienced local recurrence, and 7 experienced distant recurrence, at median 8.9 and 6.9 months post-resection, respectively. Volume changes did not predict resection margin status, local recurrence, or distant recurrence. Conclusion: Volume changes of pelvis and extremity soft tissue sarcomas followed linear trends during RT. Volume changes reflected histologic subtype and treatment characteristics but did not predict margin status or recurrence after resection.

Wear Characteristics of Particulate Reinforced Metal Matrix Composites Fabricated by a Pressureless Metal Infiltration Process (무가압함침법으로 제조된 입자강화 금속복합재료의 마모특성)

  • 김재동;정순억;김형진
    • Journal of Ocean Engineering and Technology
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    • v.17 no.1
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    • pp.55-60
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    • 2003
  • The effect of size and volume fraction of ceramic particles, with sliding velocity on the wear properties were investigated for the metal matrix composites fabricated by the pressureless infiltration process. The metal matrix composites exhibited about 5.5 - 6 times the wear resistance compared with AC8A alloy at high sliding velocity, and by increasing the particle size and decreasing the volume fraction, the wear resistance was improved. The wear resistance of metal matrix composites and AC8A alloy exhibited different aspects. Wear loss of AC8A alloy increased with sliding velocity, linearly : whereas, metal matrix composites indicated more wear loss than AC8A alloy at the slow velocity region. However, a transition point of wear loss was found at the middle velocity region, which shows the minimum wear loss. Further, wear loss at the high velocity region exhibited nearly the same value as the slow velocity region. In terms of wear mechanism, the metal matrix composites generally exhibited abrasive wear at slow to high sliding velocity; however, AC8A alloy showed abrasive wear at low sliding velocity and adhesive and melt wear at high sliding velocity.