• 제목/요약/키워드: mixtures

검색결과 4,732건 처리시간 0.038초

Prediction models of the shear modulus of normal or frozen soil-rock mixtures

  • Zhou, Zhong;Yang, Hao;Xing, Kai;Gao, Wenyuan
    • Geomechanics and Engineering
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    • 제15권2호
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    • pp.783-791
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    • 2018
  • In consideration of the mesoscopic structure of soil-rock mixtures in which the rock aggregates are wrapped by soil at normal temperatures, a two-layer embedded model of single-inclusion composite material was built to calculate the shear modulus of soil-rock mixtures. At a freezing temperature, an interface ice interlayer was placed between the soil and rock interface in the mesoscopic structure of the soil-rock mixtures. Considering that, a three-layer embedded model of double-inclusion composite materials and a multi-step multiphase micromechanics model were then built to calculate the shear modulus of the frozen soil-rock mixtures. Given the effect of pore structure of soil-rock mixtures at normal temperatures, its shear modulus was also calculated by using of the three-layer embedded model. Experimental comparison showed that compared with the two-layer embedded model, the effect predicted by the three-layer embedded model of the soil-rock mixtures was better. The shear modulus of the soil-rock mixtures gradually increased with the increase in rock regardless of temperature, and the increment rate of the shear modulus increased rapidly particularly when the rock content ranged from 50% to 70%. The shear modulus of the frozen soil-rock mixtures was nearly 3.7 times higher than that of the soil-rock mixtures at a normal temperature.

Flow and Heat Transfer Characteristics of $CO_2$/Oil Mixtures in a Circular Tube

  • Kang, Byung-Ha;Lim, Dong-Seop
    • International Journal of Air-Conditioning and Refrigeration
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    • 제16권4호
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    • pp.117-123
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    • 2008
  • The present study is directed at flow and heat transfer of $CO_2$ and oil mixtures in a circular tube. PAG and POE oils are considered in this study. Flow characteristics of $CO_2$ and oil mixtures have been investigated by flow visualization. Pressure drop has been measured in the range of operating mass flow rate from 0.1 to 0.4 kg/min in a circular tube. Heat transfer characteristics of $CO_2$/oil mixtures have been investigated using a counterflow heat exchanger. In case of pure liquid $CO_2$ as well as $CO_2$ and POE mixtures, flow are seen to be uniform so that $CO_2$ and POE oil are still miscible even at flowing state. However, it is found that $CO_2$ and PAG are not miscible. Pressure drop of $CO_2$/PAG mixtures are much higher than that of $CO_2$/POE mixtures as well as pure $CO_2$ at a fixed mass flow rate. As the concentration of POE oil is increased from 0 to 5 wt%, pressure drop is increased. However, heat transfer rate and heat transfer coefficient of $CO_2$/POE mixtures are much higher than that of $CO_2$/PAG mixtures. The f-factor correlation and Nusselt number correlation for $CO_2$/POE oil mixtures are suggested in this paper.

혼파초지의 두과초종 차이가 건물수량 및 품질에 미치는 영향 (Effect of Different Legumes on Dry Matter Yield and Quality in Mixtures)

  • 이인덕;이형석
    • Journal of Animal Science and Technology
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    • 제47권6호
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    • pp.1075-1080
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    • 2005
  • 본 시험은 2000년 9월부터 2003년 12월까지 충남대학교 생명과학대학내 부속 초지시험포장에서 수행하였다. 공시된 두과초종을 달리한 혼파초지는 alfalfa 혼파초지(AA mixtures, orchardgrass 40%+tall fescue 25%+Kentucky bluegrass 15%+alfalfa 20%), red clover 혼파초지(RC mixtures, orchardgrass 40%+tall fescue 25%+Kentucky bluegrass 15%+red clover 20%) 및 white clover 혼파초지(WC mixtures, orchardgrass 50%+tall fescue 25% + Kentucky bluegrass 15%+white clover 10%)의 3처리를 두어 시험하였다. 얻어진 결과는 다음과 같다. 3년 평균 ha당 건물수량은 white clover(WC) 혼파초지(12,469kg)가 red clover(RC) 혼파초지(11,813kg)나 alfalfa(AA) 혼파초지(10,485kg)에 비하여 높은 결과를 보였다(p<0.05). CP 함량은 WC 혼파초지가 다른 두과 혼파초지에 비하여 높았던 반면에 섬유소물질의 함량은 상대적으로 낮은 양상을 보였으며(p<0.05), 건물소화율(DMD)은 WC 혼파초지가 다른 두과 혼파초지에 비하여 높은 결과를 보였다(p<0.05). 조단백질수량(CPDM)과 가소화건물수량(DDM)은 WC 혼파초지가 RC나 AA 혼파초지에 비하여 현저히 높은 결과를 보였다(p<0.05). 2003년도 5회 마지막 예취시 AA, RC 및 WC의 식생비율은 각각 21, 36 및 48%으로 WC의 식생비율이 현저히 높은 결과를 나타내었다. 이상의 결과로 보아 건물수량, 생산된 초류의 품질을 고려할 때 WC 혼파초지가 효과적이었으나 WC의 식생유지 관리가 필요하다고 사료된다.

하번초형 혼파초지의 목초이용성 비교에 관한 연구 (A Comparative Study on the Herbage Utilization of Turf Type Mixtures)

  • 이형석;이인덕;이중해
    • Journal of Animal Science and Technology
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    • 제46권4호
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    • pp.701-706
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    • 2004
  • 본 연구는 2001년 3월부터 2001년 12월까지 충남대학교 농업생명과학대학내 부속 초지시험포장에서 하번초형 혼파초지 {Turf type mixtures: Kentucky bluegrass(Newport) 40%+tall fescue(Rebell Jr.) 20%+perennial ryegrass(Palmer II) 10%+redtop(Barricuda) 10%+red fescue(Salem) 10%+creeping bentgrass(Crenshaw) 10%}에서 수확한 1번초(4월 24일)의 목초와 상번초형 혼파초지 {tall type mixtures:orchardgrass(Potomac) 40%+tall fescue(Fawn) 20%+Festulolium braunii(Paulita) 10%+perennial ryegrass(Feveille) 10%+timothy(Climax) 10%+red clover(Kenblue) 5%+alfalfa(Vemal) 5%}에서 수확한 1번초(4월 24일)를 공시하였다. 시험축은 한국재래산양을 8두를 공시하여 건물소화율, 건물섭취량, 질소 및 에너지 이용성을 비교 분석하였으며, 얻어진 결과는 다음과 같다. 1) 건물섭취량은 하번초형 초지(28.9g/BW,kg/day)가 상번초형 초지(26.2g/BW,kg/day)에 비하여 다소 높은 편이었으나 유의적인 차이는 없었다. 세포내용물질(cellular constituents)의 소화율은 하번초형 초지가 높은 편이었으나(P<0.05), DM, NDF 및 ADF 소화율은 두 초지간에 유의적인 차이가 인정되지 않았다. 2) 외관상 생물가는 하번초형 초지(56.7%)가 상번초형 초지(56.4%)보다 높은 편이었으나 유의적인 차이는 인정되지 않았다. 3) 외관상 대사에너지 축적률은 하번초형 초지(58.3%)가 상번초형 초지(57.9%)보다 높은 편이었으나 유의적인 차이는 인정되지 않았다. 이상의 결과로 보아, 재래산양에 의한 하번 초형 목초의 이용성은 상번초형 초지에서 생산된 목초와 비교할 때 큰 차이가 없는 것으로 나타나 조사료원으로 이용가능성은 충분하다고 하겠다.

The Ergogenic Effects of Red Ginseng and Paeonia radix Mixtures

  • Cho, Tae-Young;Song, Yun-Kyung;Lim, Hyung-Ho
    • 대한한의학회지
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    • 제26권4호
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    • pp.62-73
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    • 2005
  • Objectives: This study was designed to identify the ergogenic effects of Red ginseng and Paeonia radix mixtures and optimal ratios. Materials and Methods: This study was conducted by administering treatments of Red ginseng and Paeonia radix mixtures to rats and by measuring the time to exhaustion by treadmill running. Results: The treatment of Red ginseng and Paeonia radix mixtures to the rats increased the time to exhaustion by treadmill running. The most potent inhibition of Red ginseng and Paeonia radix mixtures on the 5-HT synthesis and the TPH expression in the dorsal raphe was observed at the dose of 200 mg/kg and the optimal ratio of Red ginseng and Paeonia radix for the maximum efficacy was 50:50. Under normal conditions (not exercise), long-term treatment of Red ginseng and Paeonia radix mixtures did not affect the 5-HT synthesis and the TPH expression in the dorsal raphe, suggesting that Red ginseng and Paeonia radix mixtures does not alter serotonin level in the normal rats. The suppressive effect of Red ginseng and Paeonia radix mixtures on the 5-HT synthesis and the TPH expression during exercise is a possible ergogenic mechanism of these mixtures. Conclusions : Red ginseng and Paeonia radix mixtures reduce exercise-induced fatigue, and have the effect of acting as ergogenic aids on the time to exhaustion by treadmill exercise and on 5-HT synthesis and TPH expression.

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고기압하에서 $SF_{6}$ 혼합 가스 ($SF_{6}$/$N_{2}$)의 절연파괴에 대한 연구 (A study on the electrical breakdown in pressurized ($SF_{6}$/$N_{2}$) mixtures)

  • 이동인;이달해
    • 전기의세계
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    • 제28권4호
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    • pp.39-46
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    • 1979
  • The effective ionization coefficient in $SF_{6}$/$N_{2}$ mixtures was attempted to derive from the pure gases. Measurements of static breakdown voltage were made under the uniform field at pressures up to 4 bar in order to compare with the results obtained from this assumption. The relative performance of $SF_{6}$/$N_{2}$ mixtures to pure $SF_{6}$ was also investigated. The effect of surface roughness on discharge thresholds in $SF_{6}$/$N_{2}$ mixtures was calculated employing the simplified model and mesurements of breakdown voltages for a gap with an artificial protrustion were also made. The experimental results show that the effective ionization coefficient in gas mixtures can not be reliably estimated from the values measured for the pure gases. Therefore, basic parameters for $SF_{6}$/$N_{2}$ mixtures must be measured by investigation of the mixtures themselves. The relative performance of mixtures to pure $SF_{6}$ could be considered with the values of pR.

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Approximate Nonrandom Two-Fluid Lattice-Hole Theory. Thermodynamic Properties of Real Mixtures

  • 유기풍;신훈용;이철수
    • Bulletin of the Korean Chemical Society
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    • 제18권8호
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    • pp.841-850
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    • 1997
  • A simple molecular theory of mixtures is formulated based on the nonrandom two-fluid lattice-hole theory of fluids. The model is applicable to mixtures over a density range from zero to liquid density. Pure fluids can be completely characterized with only two molecular parameters and an additional binary interaction energy is required for a binary mixture. The thermodynamic properties of ternary and higher order mixtures are completely defined in terms of the pure fluid parameters and the binary interaction energies. The Quantitative prediction of vapor-liquid, and solid-vapor equilibria of various mixtures are demonstrated. The model is useful, in particular, for mixtures whose molecules differ greatly in size. For real mixtures, satisfactory agreements are resulted from experiment. Also, the equation of state (EOS) is characterized well, even the liquid-liquid equilibria behaviors of organic mixtures and polymer solutions with a temperature-dependent binary interaction energy parameter.

한국재래산양에 의한 혼파유형별 목초의 이용성 비교 연구 (A Comparative Study on the Herbage Utilization for Mixture Types by Korean Native Goats)

  • 이인덕;이형석
    • 한국초지조사료학회지
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    • 제25권3호
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    • pp.185-190
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    • 2005
  • 본 연구는 2000년 7월부터 12월까지 충남대학교 생명과학대학 내 부속 환경조절축사에서 수행하였다. 공시된 혼파유형별 목초는 관행 혼파초지(orchardgrass 50+tall fescue 20+perennial ryegrass 10+ Kentucky bluegrass 10+white clover $10\%$), 다초종 혼파초지(orchardgrass 40+tall fescue 20+perennial ryegrass 10+Kentucky bluegrass 10+redtop 10+alfalfa 5+red clover $5\%$) 및 단순 혼파초지(orchardgrass 80+red clover $20\%$)의 3처리를 두어 1999년 9월 7일 경운초지조성 방법에 의해 조성된 기존초지에서 수확한 1번초(4월 20일)를 재래산양에 급여하여 목초의 이용성을 비교 분석하였다. 얻어진 결과는 다음과 같다. 건물섭취량은 다초종 혼파초지(30.2g/BWkg/day)가 관행(26.5g/BWkg/day)이나 단순 혼파초지(26.9/BWkg/day)에 비하여 다소 높은 결과를 보였으나 유의적인 차이는 없었다(p>0.05). 건물소화율과 세포내용물질(cellular constituents)의 소화율은 다초종 혼파초지가 관행이나 단순 혼파초지에 비하여 높은 결과를 보였으나 (p<0.05), NDF와 ADF 소화율은 혼파유형간에 유의적인 차이가 인정되지 않았다(p>0.05). 외관상 생물가는 다초종 혼파초지$(55.1\%)$가 관행 $(54.0\%)$이나 단순 혼파초지$(53.3\%)$에 비하여 높은 편이었으나 유의적인 차이는 인정되지 않았다.(p>0.05). 외관상 대사에너지 축적률은 다초종 혼파초지$(60.2\%)$가 관행$(56.9\%)$이나 단순 혼파초지$(55.9\%)$에 비하여 높았다(p<0.05). 이상의 결과로 보아, 재래산양에 의한 초지 유형별 목초의 질소 및 에너지의 이용성은 대체적으로 다초종 혼파초지가 다른 혼파유형에 비하여 개선되는 결과를 보였다.

초종구성을 달리한 혼파 초지의 건물수량 및 품질 비교 연구 (A Comparative Study of Dry Matter Yield and Quality of Pasture Sown Different Species Seed Combination)

  • 이인덕;이형석
    • Journal of Animal Science and Technology
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    • 제47권6호
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    • pp.1081-1086
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    • 2005
  • 본 시험은 혼파유형별로 초지의 건물수량과 품질을 비교 검토하여 집약적인 경운초지에 적합한 혼파유형을 제시하고자 1999년 9월부터 2002년 12월까지 충남대학교 생명과학대학내 부속 초지시험포장에서 수행하였다. 공시된 혼파유형은 관행 혼파초지(orchardgrass 50%+tall fescue 20% + perennial ryegrass 10% + Kentucky bluegrass 10% + white clover 10%), 다초종 혼파초지(orchardgrass 40% + tall fescue 20% + perennial ryegrass 10% + Kentucky bluegrass 10% + redtop 10% + alfalfa 5% + red clover 5%) 및 단순 혼파초지(orchardgrass 80% + red clover 20%)의 3유형을 두어 시험하였다. 얻어진 시험결과는 다음과 같다. 3년 평균 ha당 건물수량은 혼파유형에 따라 차이를 보여, 다초종 혼파초지가 13,070kg/ha로 다른 관행(11,206kg)이나 단순 혼파초지(11,291kg)에 비하여 높은 결과를 나타내었다(p<0.05). 화학적성분 및 건물소화율(DMD)은 혼파휴형에 따라 차이를 보였는데, CP 함량은 다초종과 단순 혼파초지가 관행 혼파초지에 비하여 높았으며(p<0.05), 섬유소 물질의 함량은 대체적으로 관행 혼파초지에서 높은 결과를 나타내었다. 그러나 DMD는 다초종 혼파초지가 다른 혼파초지에 비하여 높은 결과를 나타내었다(p<0.05). 3년 평균 조단백질CPDM) 수량과 가소화건물(DDM) 수량은 다초종 혼파초지가 관행이나 다른 혼파초지에 비하여 높은 결과를 나타내었다(p<0.05). 이상의 결과를 종합해 볼 때, 혼파유형에 따라 건물수량과 품질이 달라지고 있음을 확인할 수 있었으며, 다초종 혼파초지가 관행이나 단순 혼파초지에 비하여 건물수량과 품질을 높이는데 효과적이라 하겠다.

혼합용매중에서의 Poly(ethylene terephthalate)섬유의 팽윤성(II) ―평형팽윤 및 수축거동― (Swelling Properties of Poly(ethylene terephthalate) Fiber in Mixed Solvent(II) ―Equilibrium Swelling and Shrinkage―)

  • Lee, Mun Cheul;Pak, Pyong Ki;Cho, Hyun Hok
    • 한국염색가공학회지
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    • 제6권4호
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    • pp.17-26
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    • 1994
  • Poly(ethylene terephthalate)(PET) filaments were treated in binary mixtures of organic solvents such as benzyl alcohol/perchloroethylene(BA/PER), benzyl alcohol/trichloroethylene(BA/TRI), benzyl alcohol/ethylene chloride(BA/EC), methanol/perchloroethylene (ME/PER), and methanol/trichloroethylene(ME/TRI). From the equilibrium swelling of PET, total and partial isotherms of PET for sorption of solvent mixtures and isotherms for distribution of the components between the phases were taken. Also the shrinkage and the crystallinity of PET treated with binary mixtures were investigated. The results obtained were summerized as follows: 1. All isotherms for distribution of the components between the phase deviated from the diagonal in system of PET-binary mixtures. Especially in the binary mixtures of ME/PER or ME/TRI, selectivo sorption of chlorinated hydrocarbon PER and TRI by PET occured. 2. The shrinkage of PET treated in binary mixrures was increased to compare with single solvent-treated, but the composition of binary mixtures corresponding to maximum values of shrinkage was not always agreed with the composition of binary mixtures corresponding to maximum values of shrinkage was not always agreed with the composition of binary mixtures exhibiting of the maximum swelling of PET. 3. The crystallinity of PET treated in binary mixtures generally increased than that of single solvent-treated.

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