• 대한기계학회논문집B
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• 제22권12호
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• pp.1763-1773
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• 1998

In the present experimental study, the flow behavior in a semi-closed two-phase natural circulation loop was examined. Water was used as the working fluid. Heat flux, heater-inlet subcooling, and flow restrictions at the heater-inlet and at the expansion-tank-line were taken as the controlling parameters Six circulation modes were identified by changing heat flux and inlet subcooling conditions ; single-phase continuous circulation, periodic circulation (A), two-phase continuous circulation, and periodic circulations (B), (C), and (D). Among these, the single-phase and two-phase continuous-circulation modes exhibit no significant oscillations and are considered to be stable. Periodic circulation (A) is characterized by the large amplitude two-phase f10w oscillations with the temporal single-phase circulation between them, while periodic circulation (B) featured by the flow oscillations with continuous boiling inside the heater section. Periodic circulation (C) appears to be the manometric oscillation with continuous boiling. Periodic circulation (D) has the longer period than periodic circulation (B) and a substantial amount of liquid flow back and forth through the expansion-tank-line periodically ; this mode is considered the pressure drop oscillation. Parametric study shows that the increases of the inlet- and expansion-tank-line- restrictions and the decrease of inlet subcooling broaden the range of the stable two-phase(continuous circulation) mode.

• 한국태양에너지학회 논문집
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• 제30권5호
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• pp.77-84
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• 2010

This paper presents the continuous commissioning process, information on the case study facility, improved system operation, and building energy consumption measures before and after continuous commissioning implementation. Continuous commissioning is an ongoing process to resolve operating problems, improve comfort, optimize energy use and identify retrofits for existing commercial and institutional buildings and central plant facilities. Continuous commissioning process consists of two phases. The first phase is the project development phase and the second phase implements and verifies project performance. Results of a case study show that continuous commissioning implementation can reduce energy costs. The energy reports show the electricity savings of 22% and gas savings of 47% on an average.

• 전자공학회논문지A
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• 제31A권7호
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• pp.29-35
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• 1994

The performance of continuous phase modulation signals is well known for the coherent demodulation. But the carrier recovery circuits of the coherent receiver have long acquisition time and the receiver experiences high error floors for fading channels. In this paper, we propose the differential demodulation of 2-h continuous phase modulation signals. The sets of modulation indices of 2-h phase codes adequate to the differential demodulation for differentially encoded input are obtained and the average bit error probability in Additive White Gaussian Noise environments is derived and analyzed.

• 한국잠사곤충학회지
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• 제40권2호
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• pp.169-175
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• 1998

The morphology of silk fibroin/poly(vinyl alcohol)(PVA)blend films was investigated using optical microscopy and confocal laser scanning microscopy. The effects of blend ratio and molecular weight of silk fibroin and PVA on phase separation were studied. Macro-phase separation occurred for the silk fibroin-rich/poor region whereas micro-phase separation took place for the dispersed/continuous phase, In spite of differences in molecular weight and blend ratio, it is observed that the dispersed phase and continuous one are composed of silk fibroin and PVA component, respectively. As the molecular weight of silk fibroin and silk fibroin content in blend ratio are decreased, the compatibility of blend is increased due to the reduction of micro-phase separation.

• 산업기술연구
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• 제18권
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• pp.267-275
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• 1998

Continuous thermodynamics has been applied for modeling of phase equilibria in multicomponent mixtures, to avoid disadvantages of the pseudo-component and key-component method. In this paper continuous thermodynamic relations formulated by using the Pate-Teja equation of state were adopted for calculations of phase equilibria in natural gas mixtures, crude oil mixtures and mixtures extracted by supercritical $CO_2$ fluids. Calculations of phase equilibria were performed by two procedures ; a moment method coupled with the beta distribution function and a quadrature method combined with Gaussian-Legendre polynomials. Calculated results were compared with experimental data. It was showed that continuous thermodynamic frameworks considered in this paper were well-matched to experimental data.

• 한국정보통신학회논문지
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• 제20권4호
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• pp.811-818
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• 2016

추가적인 부궤환 루프를 가지는 연속 미세 조절 위상 고정루프를 소개하였다. 위상고정루프가 위상이 고정되지 않았을 때 위상고정루프는 연속적인 밴드 선택 루프를 통하여 빠르게 위상을 고정시키는 특성을 가지고 있다. 위상고정루프가 고정 상태에 다다랐을 때 밴드 폭은 미세한 루프를 통해서 좁아진다. 추가적인 부궤환 루프는 안정성과 위상여유 성능을 향상시킨다. 0.18um CMOS 공정으로 제작한 위상고정루프의 결과 측정은 위상 잡음이 742.8MHz 캐리어 주파수로부터 2MHz 오프셋 주파수에서 -109.6dBc/Hz을 보여준다.

• 산업기술연구
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• 제15권
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• pp.123-135
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• 1995

In this paper, we performed the modeling of a tunable three section DFB-LD with continuous phase using the coupled-wave equation. It was also proposed new modeling method for ${\lambda}/4$ phase shifted one. We got the characteristics of oscillation wavelength, gain, and photon density profiles according to parameters such as coupling coefficient K and current into the third sections for two case of continuous phase and ${\lambda}/4$ shifted phase one. The simulations for ${\lambda}/4$ phase shifted tunable three section DFB-LD prove that the continuous tuning range is about 4.2nm for $K=120cm^{-1}$, $L=180{\mu}m$, and the oscillation mode be within the stop-bands. Also when changed a current of both end sections, it is shown that a photon density reaches the maximum at the center.

• 한국안전학회지
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• 제8권2호
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• pp.44-50
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• 1993

The objective of this study was to investigate the extraction of chromium(Vl) ion in waste water through the liquid surfactant membrane with open-type Perforated Reciprocating-Plate Column. Extraction experiments were conducted to measure the effect of flow characteristics of continuous and dispersed phase and stroke velocity, sodium hydroxide concentraction in internal aqueous phase, sulfuric acid concentraction in outer phase, and residence time distribution and measured extraction velocity. The result of experiments showed that extraction velocity of chromium ion was maximum when stroke velocity was 180 1/min and dispersion phase velocity was 30m11min, continuous phase velocity was 20m1/min. Extraction velocity of chromium ion increased with increasing difference of hydrogen ion concentraction of dispersion and continuous phase and column stage decreased.

• 한국식품과학회지
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• 제34권5호
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• pp.770-774
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• 2002

대두유 수중유적형 유화액의 산화에 미치는 surfactant micelle의 영향을 규명하기 위하여 수중유적형 유화액에서 continuous phase로 전이되는 ferric iron의 양을 측정하였다. Continuous phase로 전이된 ferric iron의 양은 첨가한 잉여의 surfactant micelle의 농도를 $0.5{\sim}2.0%$로 증가시킬수록, 저장기간이 길어질수록 증가하였다. pH 3.0에서 continuous phase로 전이된 ferric iron의 양은 pH 7.0에서 보다 높게 나타났다. Ferric iron을 함유한 대두유 수중유적형 유화액의 지방산화정도는 hydroperoxide와 headspace hexanal을 측정하여 살펴본 결과 첨가된 계면활성제의 양이 증가할수록 산화는 감소하였다. 이상의 결과로 첨가된 계면활성제에 의해 수중유적형 유화액에서 prooxidant로 작용하는 ferric iron의 위치가 변화되어 산화를 줄일 수 있을 것으로 판단하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.243-248
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• 2007

A three-dimensional (3D) unstructured hydrodynamic solver for transient two-phase flows has been developed. A two-fluid three-field model was adopted for the two-phase flows. The three fields represent a continuous liquid, an entrained liquid, and a vapour field. The hydrodynamic solver is for the 3D component of a nuclear system code and the component-scale analysis tools for transient two-phase flows. The finite volume method and unstructured grid are adopted, which are useful for the flows in a complicated geometry. The semi-implicit ICE (Implicit Continuous-fluid Eulerian) numerical scheme has been adapted to the unstructured non-staggered grid. This paper presents the numerical method and the preliminary results of the calculations. The results show that the numerical scheme is robust and predicts the phase change and the flow transitions due to boiling and flashing problems well.