• Title/Summary/Keyword: Phase Separation

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Thermodynamic Incompatibility of Food Macromolecules (식품 거대분자의 열역학적 비혼합성)

  • 황재관;최문정
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.5
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    • pp.1019-1025
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    • 1998
  • Proteins and polysaccharides are major food macromolecules. Generally, the mixture of these macromolecules can be separated into two phases because of their thermodynamic incompatibility. Phase separ-ation is explained by equilibrium phase diagram, which comprises binodal curve, critical point, phase separation threshold, tie-line and rectilinear diameter. Phase separation of protein-polysacc-haride solution is affected by pH, temperature, ionic strength, molecular weight, molecular structure, etc. Membraneless osmosis has been developed to concentrate protein solutions, using the phase diagram constituted by proteins and polysaccharides. Protein-polysaccharide mixtures are very promising fat mimetics because solution of mixtures forms water-continuous system with two phase-separated gels, which give plastic texture and a fatty mouthfeel.

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Spinodal Phase Separation and Isothermal Crystallization Behavior in Blends of VDF/TrFE(75/25) Copolymer and Poly(1,4-butylene adipate) (I) -Spinodal Phase Separation Behavior-

  • Kim, Kap Jin;Kyu, Thein
    • Fibers and Polymers
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    • v.4 no.4
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    • pp.188-194
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    • 2003
  • Phase behavior and spinodal phase separation kinetics in binary blends of a random copolymer of vinylidene fluoride and trifluoroethylene (75/25) [P(VDF/TrFE)] and poly(l,4-butylene adipate) (PBA) have been investigated by means of optical microscopic observation and time-resolved light scattering. The blends exhibited a typical lower critical solution temperature (LCST)∼${34}^{\circ}C$ above the melting temperature of the P(VDF/TrFE) crystals over the entire blend composition range. P(VDF/TrFE) and PBA were totally miscible in the temperature gap between the melting point of P(VDF/TrFE) and the LCST. Temperature jump experiments of the 3/7 P(VDF/TrFE)/PBA blend were carried out on a light-scattering apparatus from a single-phase melt state (${180}^{\circ}C$) to a two-phase region (205∼${215}^{\circ}C$). Since the late stage of spinodal decomposition (SD) is prevalent in the 3/7 blend, SD was analyzed using a power law scheme. Self-similarity was preserved well in the late stage of SD in the 3/7 blend.

Optical security system using multi-phase separation and phase-wrapping method (다중 위상 분할과 위상 랩핑 방법을 이용한 광 암호화 시스템)

  • Shin Chang Mok;Kim Soo Joong;Seo Dong Hoan
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.6 s.336
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    • pp.31-38
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    • 2005
  • In this paper, we proposed an optical security system based on a gray-image exclusive-OR encryption using multi-phase separation and phase-wrapping method. For encryption, a gray image is sliced into binary images, which have the same pixel value, and these images are encrypted by modified XOR rules with binary random images. The XORed images and the binary images respectively combined and converted into full phase images, called an encrypted image and a key image. For decryption, when the encrypted image and key image are used as inputs on optical elements, Practically due to limited controllability of phase range in optical elements, the original gray image cannot be efficiently reconstructed by these optical elements. Therefore, by decreasing the phase ranges of the encrypted image and key image using a phase-wrapping method and separating these images into low-level phase images using multi-phase separation, the gray image can be reconstructed by optical elements which have limited control range. The decrytion process is simply implemented by interfering a multiplication result of encrypted image and key image with reference light. The validity of proposed scheme is verified and the effects, which are caused by phase limitation in decryption process, is analyzed by using computer simulations.

Chiral Separation of Basic Compounds on Sulfated β-Cyclodextrin-Coated Zirconia Monolith by Capillary Electrochromatography

  • Hong, Jong-Seong;Park, Jung Hag
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1809-1813
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    • 2013
  • Sulfated ${\beta}$-cyclodextrin (SCD)-coated zirconia monolith was used as the chiral stationary phase in capillary electrochromatography for enantiomeric separation of basic chiral compounds. SCD adsorbed on the zirconia surface provided a stable chiral stationary phase in reversed-phase eluents. Retention, chiral selectivity and resolution of a set of six basic chiral compounds were measured in eluents of varying pH, composition of methanol and buffer. Optimum mobile phase condition for the separation of the compounds was found to be methanol content of 30%, buffer concentration of 30 mM and pH of 4.0.

Cyclosophoraose as a Novel Chiral Stationary Phase for Enantioseparation

  • JUNG, YUN-JUNG;LEE, SANG-HOO;PAIK, SEUNG-R.;JUNG, SEUN-HO
    • Journal of Microbiology and Biotechnology
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    • v.14 no.6
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    • pp.1338-1342
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    • 2004
  • Cyclosophoraoses (Cys), cyclic ${\beta}-(1{\rightarrow}2)-D-glucans$ produced by Rhizobium meliloti 2011, were used as a novel chiral stationary phase for the enantiomeric separation. A novel Cys stationary phase, chemically immobilized onto porous silica via aminopropyltrimethoxysilane as a molecular linker, showed good separation for each racemate of bupivacain (separation factor, $\alpha$=1.3), propranolol ($\alpha$=1.3), and fenoprofen ($\alpha$=2.9), respectively, under the mobile phase of water: methanol (80:20, v/v) at a constant flow rate of 0.9 ml/min at pH7.

A Study on Comparison of Extraction Methods of Ginseng Saponin by Phase Separation and by Extrelut Column - For Recovery Rates of Saponin - (分液 및 Extrelut Column에 依한 人蔘 Saponin 抽出方法의 比較硏究 -Saponin 回收率에 대하여-)

  • Kim, Jong Gyu;Lee, Yong Wook;Sohn, Hyun Joo;Lee, Kwang Seung
    • Journal of Environmental Health Sciences
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    • v.10 no.1
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    • pp.87-92
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    • 1984
  • Extraction method of ginseng saponin by Extrelut column was studied as compared with that by phase separation. The results obtained were as follows: 1. Extraction time consumed by Extrelut column was 2 ~ 3 hours and much shorter as compared with that by phase separation. 2. Recovery rates Of ginsenoside by Extrelut column method were 97.8 ~ 106.1% and much higher as compared with those by phase separation method.

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Numerical Simulation on Phase Separation by Using the Lattice-Boltzmann Method (Lattice-Boltzmann Method를 이용한 기체-액체 상분리 시뮬레이션)

  • Jung, Rho-Taek
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.3
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    • pp.197-201
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    • 2009
  • As one of the promising model on the multiphase fluid mixtures, the Lattice-Boltzmann Method(LBM) is being developed to simulate flows containing two immisible components which are different mass values. The equilibrium function in the LBM can have a nonideal gas model for the equation of state and use the interfacial energy for the phase separation effect. An example on the phase separation has been carried out through the time evolution. The LBM based on the statistic mechanics is appropriate to solve very complicated flow problems and this model gives comparative merits rather than the continuum mechanics model.

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Chromatographic Enrichment of Lithium Isotopes by Hydrous Manganese(IV) Oxide

  • Kim, Dong Won
    • Bulletin of the Korean Chemical Society
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    • v.22 no.5
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    • pp.503-506
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    • 2001
  • Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. One molar CH3COO Na solution was used as an eluent. The heavier isotope of lithium was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was calculated according to the method of Glueckauf from the elution curve and isotopic assays. The single stage separation factor of lithium isotope pair fractionation was 1.021.

Anisotropic Acorn-like Particle Fabrication Via a Dynamic Phase Separation Method (동적 상분리법을 이용한 이방성 도토리형상 입자 제조)

  • Park, Chul Ho;Baek, Il-hyun
    • Membrane Journal
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    • v.29 no.1
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    • pp.61-65
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    • 2019
  • Anisotropic particles have been issued in various fields due to their unique physical properties. Herein, a novel dynamic phase separation method (DPS) is introduced to fabricate anisotropic acorn-like nanoparticles. DPS consists of two dynamic conditions; solvent evaporation and nonsolvent induced precipitation. The bottom layer is controlled by feeding the water as a non-solvent diluent, and the phase separation of the upper layer relies on the diffusion and evaporation of a volatile good solvent. At this condition, the acorn-like particles were fabricated. Under a closed box filled with water (spontaneous phase separation), monodisperse polystyrene (PS) particles were synthesized. At the coexistence between DPS and spontaneous phase separation, the sizes of cap and particle were changed. Also, the volume of PS solutions influences on the particle shape. Since the unique structures could be utilized into various applications, if advanced techniques such as membrane-based controlled water feeding is developed, monodisperse acorn-like particles could be tuned.