• Title/Summary/Keyword: phase diagram

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Thermodynamic Assessment of the PbO-ZrO2 System

  • Koo, Bon-Keup;Ping Liang;Hans Jiirgen Seifert;Fritz Aldinger
    • The Korean Journal of Ceramics
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    • v.5 no.3
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    • pp.205-210
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    • 1999
  • The thermodynamic properties and phase diagram of the$ PbO-ZrO_2$ system have been critically assessed using the Thermo-Calc program. Excess Gibbs energies were expressed by Redlich-Kister polynomials for the solid phases, by the two-sublattice ionic liquid model for the liquid phase and by the compound energy model for the solid solution phase. All solid phases were treated as stoichimetric compounds.

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A Study on the Generation of Crew Scheduling Diagram Using Neighborhood Search Method for Improving Railway Operation Management (철도 운영관리 효율화를 위한 이웃해 탐색기법을 사용한 승무다이아 생성방안)

  • Lee, Jaehee;Park, Sangmi;Kang, Leenseok
    • Korean Journal of Construction Engineering and Management
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    • v.20 no.5
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    • pp.42-51
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    • 2019
  • The train operation institution establishes a transportation plan based on the forecast of transport demand and the ability of train vehicles to transport, and establishes a train operation plan accordingly. The train operation plan adjusts the intervals between trains, creates a timetable (train diagram) for trains, and establishes a plan for the operation of train vehicles used for train operation. The train operation institution shall establish a crew schedule to determine and place the crew members of the trains arranged in the diagram in order to enhance the efficiency of the operation management of the trains. In this study, the authors apply the neighborhood search method that satisfies the constraints at the phase of generating the crew diagram. This suggests a methodology for efficient management of crew schedule plan. The crew diagram generated in this study compared with the existing crew diagram in accordance with the actual operating train timetable, and verified the effectiveness of the suggested method.

Development of Lecithin Organogel to Improve Solubility of Genistein (레시틴 오가노겔을 이용한 난용성 제니스테인의 용해도 향상)

  • Lee, Su Jin;Kim, Jung A;Kang, Nae Gyu;Park, Sun Gyoo;Lee, Cheon Koo
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.41 no.3
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    • pp.201-208
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    • 2015
  • Organogels are semi-solid systems that consist of an apolar solvent as the liquid phase within a three-dimensional networked structure. In this study, we developed a stable and skin penetration-enhanced Lecithin Organogel (LO) containing genistein, which is one of the poorly soluble active ingredients in both polar and apolar phase. After screening of various components (type of gelators, organic and aqueous phase), hydrogenated lecithin (HL), sunflower oil (SO), dipropylene glycol (DPG), and polyethylene glycol (PEG) were mainly used in this formulation. Phase ternary diagram was employed for optimization of the composition in the LO. The formulated LO were evaluated for its organoleptic characteristics, stability, pH, rheology, phase transition temperatures, microscopic analysis and skin penetration. The optimized stable LO system can be utilized as an effective and stable cosmetic formulation that can carry poorly soluble active ingredients at high concentration for topical dermal delivery.

Estimating the Glass Transition of Oligosaccharides Mixtures through the State Diagram

  • Auh, Joong-Hyuck;Park, Kwan-Hwa
    • Food Science and Biotechnology
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    • v.14 no.2
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    • pp.301-303
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    • 2005
  • State diagram of highly concentrated branched oligosaccharides (HBOS) was constructed to better understand phase behavior of mixtures with different size of oligosaccharides. It showed dramatic plasticizing effect on glass transition, which was successfully described based on Couchman-Karasz equation model. $T_g$' estimated from state diagram corresponded well with previous empirical data measured by maximum ice formation through isothermal holding (annealing) process. Estimated $T_g$' and $C_g$' values were $-36.3^{\circ}C$ and 79.99%, respectively. $T_g$' value of HBOS was approximately $10^{\circ}C$ higher than that of sucrose, while $C_g$' value was similar to those of general carbohydrate materials, which could be useful for applications in frozen system.

A Study on the Development of Life Cycle Cost Analysis Methodology in HVAC system for Decision Maker (의사 결정자를 위한 HVAC 시스템의 LCC 분석 방법론 개발에 관한 연구)

  • Jung, Soon-Sung
    • Journal of the Korean Solar Energy Society
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    • v.24 no.4
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    • pp.55-63
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    • 2004
  • The purpose of this study is to development of life cycle cost analysis methodology of HVAC system for decision maker. The results of this study are as follows; maintenance/management, equipment construction, planning/design, and demolition/sell phases (1) To develop the cost breakdown structure for LCC in HVAC system, this study apply the method of additional pertinent level, title, CBS number, block number and variable index. (2) LCC analysis order of HVAC system compose four phase. (3) Life cycle costing influence diagram can bring us to make the most efficient decision through a visual graphical diagram that is shown relationship among variables and that decision maker traces easily from life cycle cost analysis situation.

A Practical Method of Balancing a Rigid Rotor

  • Su, Hua;Chong, Kil-To
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.2
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    • pp.36-40
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    • 2006
  • Diagnosis and repair tasks of an unbalanced rigid rotor reduce the chances of unexpected failure and the consequent losses in production, time, and money. This paper presents investigation of a balancing system for equilibration of rigid rotor unbalance. A practical vibration signal based method is developed for unbalance diagnosis using wavelet technology and a Lissajous diagram. This paper shows that a mass unbalance can be efficiently estimated through an appropriate narrow-band filter used to extract the required spectra component. The wavelet technology is used to design specified narrow filter bank. A modified Lissajous diagram is also introduced with statistical analysis to compute the phase position. Several experimental tests demonstrate the effectiveness in balancing the mass unbalance of a rigid rotor.

Slow Wave Circuits for Traveling-Wave-Type Amplifiers (진행파형 증폭기를 위한 저속파회로)

  • 김봉열;황금찬
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.7 no.2
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    • pp.13-20
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    • 1970
  • The dispersion characteristics of tape meander line were analyzed by electromagnetic field theory. The several different tape meander lines were photoetched on copper printed-bakelit substrate, and these tape meander line structures were inserted into the X-band waveguide. Phase bridge method was used for the dispersion characteristics measurement of meanderline. The measured. results were plotted on diagram(Brillouin diagram) and compared with theoretical values. Measured results were consistent with theoretical Values. But, on the measured diagram, passband midfrequency was lower than theoretical value. It was believed that the discrepancy was due to the backelite loading. The group velocity of stagger tuned meander line was higher than that of uniform meander live, and the freqnency band of constant group velocity of stagger tuned meanderline was sider than that of uniform meander line.

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Construction and Utilization of McCabe-Thiele Diagram for the Solvent Extraction (용매추출에서 McCabe-Thiele도의 작성 및 이용)

  • Lee, Man Seung
    • Resources Recycling
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    • v.27 no.4
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    • pp.65-69
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    • 2018
  • In solvent extraction, extraction isotherm represents the relation between the equilibrium concentration of metal in the aqueous and organic phase. McCabe-Thiele diagram on which extraction isotherm and operating line are constructed provides valuable information on the mass transfer operation. When the equilibrium constant of a solvent extraction reaction is known, the calculation method to obtain extraction isotherm was introduced. Kresmer equation by which the number of extraction stages can be calculated when the distribution coefficient is constant was introduced.

A Research of Secondary School Chemistry Major Teachers’ Perceptions on the Drying Phenomenon of Frozen Wash (언 빨래가 마르는 현상에 대한 중등학교 화학전공 교사들의 인식 조사)

  • Baek, Seong-Hye;Kim, Hyeon-Hui;Yang, Gi-Chang;Kim, Dong-Uk
    • Journal of the Korean Chemical Society
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    • v.50 no.1
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    • pp.65-78
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    • 2006
  • study identified secondary school chemistry major teachers' perceptions of sublimation related to the drying phenomenon of frozen wash and representation of the phenomenon on phase diagram. The subjects were 53 teachers for the questionnaire developed for this study, and interviews. The two professors who majored physical chemistry and one professor who majored analytical chemistry at teacher's college were interviewed for teacher educators' perceptions of sublimation. The results showed that forty one teachers among fifty three teachers thought that the drying phenomenon was sublimation. The most teachers who thought that the phenomenon was sublimation responded as a reason that solid state changes to gas state. The teachers who thought that the phenomenon was not sublimation responded as a reason that the 1 atm of air pressure was not the condition of sublimation. Seventeen teachers thought that the drying phenomenon of frozen wash could be represented on phase diagram, but thirty four teachers thought that it could not. But most teachers confused the scientific representation of the phenomenon, and felt difficulties to teach the contents to students.