• Title, Summary, Keyword: partition coefficient

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The Performance Assessment of a Straight-Type Five-Hole Pressure Probe Using a Zone Partition and Two-Dimensional Curve-Fitting Functions (영역분할과 2차원 커브피팅 함수들을 이용하는 직선형 5공 압력프로브의 성능 평가)

  • Kim, Jang-Kweon;Oh, Seok-Hyung
    • Journal of the Korea Society For Power System Engineering
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    • v.18 no.1
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    • pp.22-31
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    • 2014
  • This paper introduced the new calibration algorithm of a straight-type five-hole pressure probe necessary for calculating three-dimensional flow velocity components. The new velocity data reduction method using both a commercial two-dimensional curve-fitting program and the zone partition method of a calibration map was firstly introduced in this study. This new calibration method can be applied up to the wide flow angle of ${\pm}80^{\circ}$ despite of using a five-hole pressure probe because this data reduction method showed a comparatively good performance in calculating yaw and pitch angles from the calibration map.

Computation of Wave Propagation over Multi-Step Topography by Partition Matrix Method (분할행렬법에 의한 다중 계단지형에서의 파랑변형 계산)

  • Seo, Seung-Nam
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.4B
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    • pp.377-384
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    • 2009
  • In order to reduce computing time significantly for a large matrix in EFEM of linear waves propagation over ripple beds, each of which is approximated to a multi-step topography, a partition method is presented to calculate reflection coefficients. By use of 10 evanescent modes in the model, the most accurate numerical solutions have been obtained up to date, which show different behaviors of computed reflection coefficient in some cases against the existing results. Both computing time and memory of the present partition model for solving a large matrix are still so much demanding that it is needed to develop an efficient method.

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The Determination of Diffusion and Partition Coefficients of PUF (폴리우레탄 폼의 휘발성 유기화합물 확산 및 분배계수 산정)

  • Park, Jin-Soo;Little, John C.;Kim, Shin-Do;Lee, Hee-Kwan;Kong, Boo-Ju
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.1
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    • pp.77-84
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    • 2010
  • The diffusion and partition coefficients of polyurethane foam (PUF) are estimated using a microbalance experiment and small chamber test. The microbalance is used to measure sorption/desorption kinetics and equilibrium data. When the diffusion condition is controlled in the chamber of the sample, interactions between volatile organic compounds (VOCs) and PUF can lead to the estimation of a relatively homogenous rate of mass transfer in the interiors and surfaces of PUF. The estimates of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) are shown to be independent of the concentrations of VOCs. This approach, if applied to a diffusion-controlled or physically-based model, can facilitate more precise prediction of their source/sink behavior. Although further research and more rigorous validation is needed, an emission model applied with the diffusion and partition coefficients from this research holds promise for the improvement of reliability in predicting the behavior of VOCs emitted from porous building materials by D and K.

Formation of PEG/Dextran Aqueous Two-Phase System for Starch Hydrolysis Using $\alpha$-Amylase ($\alpha$-Amylase로 전분 가수분해를 위한 PEG/Dextran 수성 2상계 구성)

  • 박병춘;임동준
    • Microbiology and Biotechnology Letters
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    • v.20 no.2
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    • pp.190-195
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    • 1992
  • In the polyethylene glycol/dextran aqueous two-phase systems, volume ratio was increased and partition coefficient was decreased with the increase of potyethylene glycol molecular weight and concentration. However the volume ratio was decreased and the partition coefficient was increased with the increase of dextran molecular weight. On the other hand, the volume ratio and the partition coefficient were decreased with the increase of dextran concentration. Continuous enzymatic hydrolysis of soluble starch with $\alpha$-amylase which was produced by Bacillus amyloliquefaciens IF0 14141 was investigated in polyethylene glycol/dextran aqueous two-phase systems. Nonreacted soluble starch and $\alpha$-amylase were reused in these systems. $\alpha$-Amylase activity was maintained more than 100 hrs by recycling of $\alpha$-amylase from bottom of settler to reactor.

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A Computational Study of Natural Convection in Vertical Rectangular Enclosures with Partiton Plates of Finite Thermal Conductivity (유한열전도율(有限熱傳導率)의 격판(隔板)을 갖는 수직구형(垂直矩形) 밀폐공간(密閉空間)에서의 자연대류(自然對流)에 관(關)한 수치적(數値的) 연구(硏究))

  • Park, Man-Heung;Lee, Jae-Heon
    • Solar Energy
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    • v.2 no.1
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    • pp.1-8
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    • 1982
  • A theoretical study by numerical method has been performed on the natural convection of an air contained in enclosures. The enclosures have rectangular cross section with one vertical wall heated and the other cooled, and with two horizontal partition plates of finite thermal conductivity. Steady two-dimensional flow was assumed. The computation was executed by means of the Implicit Alternating Direction (I.A.D) finite-difference method. Two partition plates of Aluminium whose thickness were 0.05mm was employed in computation. Isothemals, streamlines, local Nusselt numbers and mean Nusselt numbers were obtained for various Grashof numbers and aspect ratio and these results were compared with those in the case of the enclosure with two horizontal insulated plates. From the present results, the heat transfer in the case of partition plates was greater than that in the case of insulation. This study suggests a method to measure the overall heat-transfer of coefficient in double walls which supported by partition plates for insulative construction.

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Production of Cyclodextrin Homologues Using Aqueous Two-Phase System

  • Chang, Woo-Jin;Koo, Yoon-Mo;Park, Sung-Sik
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.2 no.2
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    • pp.97-100
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    • 1997
  • Cyclodxtrin homologues(CDs), produced by cyclodextrin glycosyltransferase(CGTase), were simultaneously partitioned in aqueous two-phase system(ATPS). Partition coefficients of CDs were measured in PEG/dextran systems. Phosphate, citrate, sulfate were tested as salt. ATPS of PEG/salt and PEG/dextran had the partition coefficients of the CDs, larger than unity. However, PEG/dextran system was observed better than PEG/salt as CGTase activity decreased sharply with salt concentration. Enzymatic rection occurred mainly in PEG-rich bottom phase because of the low partition coefficient of CGTase. The resulting CDs transferred to the PEG-rich top phase, obeying the diffusional partition. In the ATPS of 7% PEG(M.W.40, 000), 7mg/ml of CDs were obtained in top phase at 4.5 hours.

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Effects of Salts on the Partition of Proteins in Poly (ethylene glycol)-Dextran Aqueous Two Phase System (Poly(ethylene glycol)-dextran 수용액 2상계에서 단백질 분획계수에 미치는 금속염의 효과)

  • Lee, Sam-Pin;Lee, Cherl-Ho
    • Korean Journal of Food Science and Technology
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    • v.19 no.2
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    • pp.146-150
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    • 1987
  • The effects of pH and added salts on the partition coefficients of proteins in a polyethylene glycol)-dextran aqueous two-phase system were investigated. The partition coefficients attained the lowest value at the isoelectric point of proteins in an equal volume aqueous two-phase system containing 5% PEG and 9.5% dextran in 5 mM phosphate buffer solution. The coefficients increased dramatically at pH 11; BSA which had highest effective hydrophobicity marked 50-fold increase, while ${\beta}-lactoglobulin$ and ovalbumin which had low hydrophobicity 10-fold increase, respectively. The effect of added salts varied with the pH. The partition coefficient increased by the addition of salt at pH 3.0 but decreased drastically at pH 7.0. The partition coefficient increased in the order of added Li < Na < K at pH 3.0 and decreased in the order of added Li < Na < K at pH 11.0.

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Development of Cefazolin Prodrug for Oral Administration -Synthesis, Partition Coefficient and Antibacterial Activity of Cefazolin Ethoxycarbonylethyl Ester- (세파졸린의 경구투여를 위한 프로드럭의 개발 -세파졸린 에톡시카보널에칠 에스텔의 합성, 분배계수 및 항균력-)

  • Jung, Young-Guk;Burm, Jin-Pil;Choi, Jun-Shik;Lee, Jin-Hwan
    • Journal of Pharmaceutical Investigation
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    • v.24 no.4
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    • pp.265-271
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    • 1994
  • Cefazolin ethoxycarbonylethyl ester (CFZ-ET) was synthesized to improve oral absorption and bioavailability of the parent drug by esterification of sodium cefazolin (CFZ-Na). The successful synthesis of CFZ-ET was identified with analysis of UV spectra, FT-lR spectra and NMR spectra. Partition coefficient studies showed that CFZ-ET was more lipophilic than CFZ-Na and the ester was hydrolyzed into the parent drug in vivo. Although CFZ-ET did not have antimicrobial activity in vitro, the plasma taken after the oral administration of CFZ-ET had antimicrobial activity. Based on above observations, CFZ-ET might be rapidly hydrolyzed to CFZ in the body. Therefore, it may be concluded that CFZ-ET could be a novel prodrug of CFZ which can improve the bioavailability of CFZ-Na.

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ESTIMATION OF RAIN SCAVENGING RATIO FOR PARTICLE BOUND POLYCYCLIC AROMATIC HYDROCARBONS AND POLYCHLORINATED BIPHENYLS

  • Kim, Hyeon-Kook;Shin, Yong-Seung;Lee, Dong-Soo;Song, Byung-Joo;Kim, Jong-Guk
    • Environmental Engineering Research
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    • v.11 no.1
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    • pp.33-44
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    • 2006
  • The objective of this study was to develop and assess a method for estimating the rain scavenging ratios (RSRs) of particle-bound PAHs and PCBs using measured scavenging ratio of particulate matters (PM) and routinely available data of physico-chemical properties of PM. Paired atmospheric and rainwater sampling was conducted for a total of 4 rain events. Assuming equilibrium partitioning in rainwater-gas-PM system, an equation was derived for estimating the RSR of particle-bound chemicals as a function of RSR of PM and three equilibrium partition constants (i.e. dimensionless Henry's law constant, gas-particle partition coefficient, and water-particle partition coefficient). For all PAHs, the model significantly under-predicted the RSR while the model prediction for PCBs agreed with observation mostly within a factor of 5. The RSR model for the chemicals is of limited use as its accuracy critically depends on how close the observed partitioning of the chemicals in the gas-PM-rainwater system is to that estimated under the equilibrium assumption.