• 제목/요약/키워드: Chemical and physical characteristics

검색결과 1,510건 처리시간 0.027초

SORET AND CHEMICAL REACTION EFFECTS ON THE RADIATIVE MHD FLOW FROM AN INFINITE VERTICAL POROUS PLATE

  • MALAPATI, VENKATESWARLU;DASARI, VENKATA LAKSHMI
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제21권1호
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    • pp.39-61
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    • 2017
  • In this present article, we analyzed the heat and mass transfer characteristics of the nonlinear unsteady radiative MHD flow of a viscous, incompressible and electrically conducting fluid past an infinite vertical porous plate under the influence of Soret and chemical reaction effects. The effect of physical parameters are accounted for two distinct types of thermal boundary conditions namely prescribed uniform wall temperature thermal boundary condition and prescribed heat flux thermal boundary condition. Based on the flow nature, the dimensionless flow governing equations are resolved to harmonic and non harmonic parts. In particular skin friction coefficient, Nusselt number and Sherwood number are found to evolve into their steady state case in the large time limit. Parametric study of the solutions are conducted and discussed.

물리, 화학 및 생물학적 방법에 의한 안료폐수의 적정처리 및 재이용 가능성 평가 (The Appropriate Treatment and Reuse Ability Assessment of Pigment Wastewater by Physical, Chemical, and Biological Process)

  • 정종식;옥치상
    • 한국환경과학회지
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    • 제7권1호
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    • pp.81-88
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    • 1998
  • This study was conducted to assess the characteristics of plgment wastewater and the removal rates of appropriate treatment by physical, chemical and biological Process, and the possibility of reuse for effluent. Based on the results, the wastewater qualities of pigment were pH 5.1$\pm$3.4, temperature 43.0$\pm$ 15.$0^{\circ}C$, BOD 1,431.4$\pm$589.6mg/l, COD 2,282.8$\pm$466.5mg/l, turbidity 1,340$\pm$820NTU, color 243.0$\pm$147.0unit, Pb 36.5$\pm$9.5mg/l and $Cr^+6$ 10.3$\pm$ 1.3mg/l, respectively. The removal rates of adsorption by activated carbon and filter process were BOD 40.6% , COD 57.0% , turbidity 89.6%, color 87.2%, Pb 86.0% and $Cr^+6$ 10.6%, respectively. And the removal rates of reduction, neutralization, coagulation and aP floatation process were BOD 18.2%, COD 24.3%, turbidity 74.3%, color 56.7%, Pb 68.6% and $Cr^+6$ 97.8%, respectively. The removal rates of activated sludge process were BOD 95.9%, COD 86.0%, turbidity 27.8%, color 25. 2%. Pb 26.9% and $Cr^+6$ 50.0% , respectively. The total removal rates of treatment by physical, chemical and biological process were BOD 98.0% , COD 95.4%, turbidity 98.1%, color 95.8%, Pb 97.0% and $Cr^+6$ 99.0%, respectively. According to the test results for possibility of reuse with coagulation-adsorption by activated carbon process of effluent, COD was higher than that of raw water and others were similar to that of raw water thus, it Is considered to be reused.

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Electrochemical Characterization of Nanosized Electrode Arrays Prepared from Nanoporous Self-Assembled Monolayers

  • Choi, Shin-Jung;Park, Su-Moon
    • Bulletin of the Korean Chemical Society
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    • 제23권5호
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    • pp.699-704
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    • 2002
  • We characterized nanoelectrode arrays prepared from self-assembled monolayers (SAMs) by adsorption from a solution containing thiolated $\beta$-cyclodextrin ($\beta$-CD) and n-alkanethiol on the gold electrode surface, using electrochemical methods. While the framework, the n-hexadecanethiol SAM, effectively blocked electron transfer between the electrode surface and solution-phase redox probe molecules, the $\beta$-CD cavities isolated in the forests of n-hexadecanethiol molecules were shown to act as an ultramicroelectrode array. The shapes of cyclic voltammograms of probe molecules were related to the number densities of $\beta$-CD molecules within the monolayer films. Probe molecules that have the correct combination of physical and chemical characteristics were shown to effectively penetrate the framework through the $\beta$-CD pores and exchange electrons with the electrode surface.

Norbornene Dialkyl Ester가 첨가된 Isoprene Rubber의 가공성 및 물성에 관한 연구 (A Study on Processing and Physical Properties of Isoprene Rubber Involving Norbornene Dialkyl Ester)

  • 정혜인;조남철;우제완
    • 공업화학
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    • 제27권3호
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    • pp.259-264
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    • 2016
  • 본 연구에서는 norbonene dialkyl ester 6종을 isoprene rubber에 적용하여 내분비계 교란물질인 DEHP에 대한 대체 가능성을 평가하였다. IR 시편은 isoprene rubber (IR)와 norbonene dialkyl ester, 가황제 등을 배합하여 제작하였으며, 토크값, 스코치 시간, 최적가황시간, 무니점도를 측정하여 가공성을 평가하였고, 경도, 인장강도, 100% modulus, 신율 등물성을 평가하여 이를 DEHP를 적용한 경우와 비교하였다. 그 결과 토크 값의 경우 최저토크, 최대토크 모두 DEHP 보다 낮거나 유사한 값을 나타내었고, 스코치 시간, 최적가황시간은 DEHP보다 같거나 길게 측정되었다. 무니점도는 DEHN이 낮은 값을 나타내어 DEHP를 첨가한 경우보다 가공성이 우수함을 확인하였다. 경도와 열적 특성의 경우 norbornene계 화합물이 DEHP와 같거나 유사한 경향을 보였다. 인장특성의 경우 선형의 알킬기를 가진 norbornene계 화합물을 적용한 경우가 우수함을 확인하였다.

HCl분위기에서 증기열처리된 BPSG 막의 평탄화효과에 관한 연구 (Planarization Effect of Steam Densified BPSG Film in HCl Atmosphere)

  • 김동현
    • 한국세라믹학회지
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    • 제23권4호
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    • pp.55-61
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    • 1986
  • Phosphosilicate glass(PSG) films have been used as fusable deposited dielectrics in silicon gate MOS integrated circuits. But in this experiment BPSG(borophosphosilicate glass) will be optimized for more efficient utilization of the reactants. The BPSG films were deposited on silicon wafers by the oxidation of the hydrides at 430$^{\circ}$C in conventional atmospheric-pressure chemical-vapor-deposition (CVD) systems. Physical and chemical properties of CVD BPSG films have been characterized both for as-deposited and for fused films The. relationship between deposited BPSG film composition and infra-red absorption solution etch rate and fusion temperature is discussed and examples of BPSG composition that can be fused at 900~95$0^{\circ}C$ and 800~85$0^{\circ}C$ are given. In addition to having lower fusion temperature than PSG films BPSG films have lower as-deposited intrinsic tensile stress and low aqueous chemical etch rate they have been considered for applications where these characteristics are advantageous.

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무당개구리의 복피 Carotenoid 색소에 관한 연구 (제1보). ${\beta}$-Carotene과 4-Hydroxy-echinenone의 분리 및 확인 (Studies on the Carotenoid Pigments in the Abdominal Skin of Bombina Orientalis (I). Occurrence of ${\beta}$-Crotene and 4-Hydroxy-echinenone in the Abdominal Skin of Bombina Orienialis)

  • 장세희;정의준
    • 대한화학회지
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    • 제18권4호
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    • pp.289-296
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    • 1974
  • Bombina Orientalis(무당개구리)의 복피로부터 암적색의 색소를 추출하여 TLC 및 column chromatography 로 10여종의 carotenoid를 분리하여 visible 및 IR-spectrum을 조사하였다. 물리, 화학적 성질, chromatomatographic 성질 visible 및 IR-spectral 특성을 이용하여 주색소는 ${\beta}$-carotene과 4-hydroxy-echinenone임을 확인하였다.

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디메틸에테르에 첨가된 윤활성향상제의 윤활특성에 관한 연구 (Study on Lubrication Characteristics of Lubrication for Lubricity Improver in Dimethyl Ether)

  • 박천규;장은정;정충섭;이봉희;나병기
    • Tribology and Lubricants
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    • 제29권2호
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    • pp.117-123
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    • 2013
  • Dimethyl ether (DME) has a high cetane number that is suitable for diesel fuel. DME does not contain sulfur or nitrogen, and is an oxygenated fuel so it produces no particulate matter when combusted and is environmentally friendly. DME fuel for diesel engines show excellent material properties such as a lower volumetric heating value, lower boiling point, lower lubricity, and stronger solvent effect than light oil. This study experimentally examined a lubricity improver (LI) for dimethyl ether. A diesel LI based on biodiesel and fatty acid methyl ester was tested among DME LI candidates. The long-term storage stability and physical properties of the optimum LI for DME were determined.

무당개구리의 복피 Carotenoid 색소에 관한 연구 (제5보). $\gamma$-Carotene, Torulene, 5,6-Monoepoxy-$\alpha$-carotene 유사물 및 Lutein Monoester의 분리 및 확인 (Studies on the Carotenoid Pigments in the Abdominal Skin of Bombina Orientalis (V). Occurrence of Some Minor Carotenoids, $\gamma$-Carotene, Torulene, 5,6-Monoepoxy-$\alpha$-caroten-like, and Lutein Monoester)

  • 장세희;정의준
    • 대한화학회지
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    • 제24권4호
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    • pp.310-314
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    • 1980
  • 무당개구리의 복피색소로부터 lutein monoester, torulene, $\gamma$-carotene 및 5,6-monoepoxy-$\alpha$-carotene 유사물을 분리 및 정제하여 BIS-UV 및 IR 스펙트럼 특성, 크로마토그래피적 성질 및 물리화학적 성질을 이용하여 그들의 구조를 확인하였다.

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무당개구리의 복피 Carotenoid 색소에 관한 연구 (제4보). Lutein 과 3,3'-Dihydroxy 3,4,3',4'-Bisdehydro-${\beta}$-Carotene 의 분리 및 확인 (Studies on the Carotenoid Pigments in the Abdominal Skin of Bombina Orientalis (Ⅳ). Occurrence of Lutein and 3,3'-Dihydroxy-3,4,3',4'-bisdehydro-${\beta}$-Carotene in the Abdominal Skin of Bombina Orientalis)

  • 장세희;정의준;최일영
    • 대한화학회지
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    • 제20권6호
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    • pp.514-519
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    • 1976
  • 무당개구리의 복피 색소로부터 주 색소의 일부인 lutein과 3,3'-dihydroxy-3,4,3',4'-bis-dehydro-${\beta}$-carotene을 분리하여 물리 화학적 성질, 가시광선 및 적외선 스펙트럼 특성, 그리고 크로마토그래피적 성질을 이용하여 그들의 구조를 확인하였다.

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무당개구리의 복피 Carotenoid 색소에 관한 연구 (제3보). 3-Hydroxy-canthaxanthin의 분리 및 확인 (Studies on the Carotenoid Pigment in Abdominal Skin of Bombina Orientalis (Ⅲ). Occurrence of 3-Hydroxy-canthaxanthin in the Abdominal Skin of Bombina Orientalis)

  • 장세희;정의준;최일영
    • 대한화학회지
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    • 제19권1호
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    • pp.34-37
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    • 1975
  • 무당개구리의 복피 색소로 부터 작자색 침상결정인 3-hydroxy-anthaxanthin을 분리하였다. Visible과 IR 스펙트럼의 특성, 크로마토그래피적 성질 및 물리화학적 성질을 이용하여 그의 구조를 확인하였다.

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