실제 증기 건도 예측 모델의 비교

김지민,박주용,이지수,이성우,심재우 한국공업화학회 2003 응용화학 Vol.7 No.1

Three representative models for the reediction of true mass fraction of steam were compared and analyzed to determine most appropriate model that can used to predict the Critical Heat Flux (CHF) for flow of wate in uniformly heated vertical tubes, The models studied were Kroeger & Zuber's [1]. Levy's[2] and Jafri et al.'s[3]. for the comparison. 188 data points from Becker et al.[4] (10 MP a data) were selected as a representative sample from the CHF database that contains a total of 8.912 data points. In case of Kroeger & Zuber vs. Jafri et al., the average error was 0.33% and the root mean square error was 2.47%. In case of Levy vs. Jafri et al., the average and root mean square errors were 1.66%, 2.67% respectively. Jafri et al.'s model can be applied to both uniform and non-uniform heated tubes because it is in a from of rate equation that can easily be used for calculating the true fraction of steam along the length of tube.

균일 가열 수직 원형관에서의 일반화된 임계열유속 예측 상관식 개발

이성우,박주용,이지수,심재우 한국공업화학회 2004 응용화학 Vol.8 No.1

A new generalized CHF (Critical Heat Flux) correlation was suggested for water flow in uniformly heated vertical round tubes. The parametric ranges of experimental data were as follows : 0..101≤p (pressure) ≤ 20.679 MPa, 9.92 ≤ G (mass flux) ≤ 18,619.39 lg/㎡s, 0.00102 ≤ D (diameter) ≤ 0.04468 m, 0.03 ≤ L (length) ≤ 4.97 m, -609.33 ≤ Inlet subcooling ≤ 1,655.34 kJ/kg, 0.11 ≤ q_(c) (CHF) ≤ 21.41 MW/㎡, and -0.87 ≤ X_(e) (exit qualities) ≤ 1.58. The new correlation was based on the local condition hypothesis. The new correlation was compared with 4 existing CHF correlation from world literature that claimed to have comparatively good predictions. The results of this study showed that prediction of CHF by the new correlation was in very good agreement with 8,951 experimental CHF data points composed of 12 different sources[1]. The new correlation predicted CHF better than the other ones with average error of -1.34% and root mean square error of 13.44%.

활성탄의 종류에 따른 P-Chlorophenol의 Kinetic 흡착 특성에 관한 연구

김지민,이성우,이지수,박주용,심재우 한국공업화학회 2003 응용화학 Vol.7 No.1

Adsorption characteristics of P-Chlorophenol on Activated Carbon Fiber (ACF) and Granular Activated Carbon (GAC) were investigated. The influence of initial P-Chlorophenol concentration on rate of adsorption was studied. The adsorption rate of activated carbon fiber was much higher than the granular activated carbon. The kinetic coefficients of adsorption process of P-Chlorophenol on each carbon were determined experimentally and used in the model to predicted the adsorption The adsorption experimentally and used in the model to predicted the adsorption. The adsorption prediction on ACF required a modification of adsorption amount (qm) of Freundlich's equilibrium adsorption to predict accurately in the model used.

인쇄회로기판 제조 공정에 대한 냉각판 구조의 영향

이지수,김지민,박주용,이성우,심재우 한국공업화학회 2004 응용화학 Vol.8 No.1

Because of strong demand of compacted consumer electronics and rapid improvements in the miniaturization of electronic devices, compact or high density multi-layered PCBs (Printed Circuit Board) production facility with high productivity is being actively sought out. In the cooling process of lamination, it is very important to diminish the temperature deviation within the epoxy resin with respect to the position of press. In this study, we measured the temperature distribution of cooling process for CCL (Copper Clad Laminate) manufacturing. As the result, temperature change in the first plate was bigger than the one in the sixth plate. Much higher efficiency of cooling was observed when copper separator was used compared to the cooling at the natural convection state. In addition, when cooled by the copper plate, the temperature deviation between plates in CCL went up to maximum of 9 degrees.

균일 가열 수직 원형관에서의 전영역 임계열유속 예측 상관식 개발을 위한 파라미터의 경향성 분석

이지수,이성우,김지민,박주용,심재우 한국공업화학회 2002 응용화학 Vol.6 No.2

The important parameters that have significant effects on the prediction of CHF(Critical Heat Flux) were investigated. This was the preliminary study for ageneralized CHF correlation in uniformly heated vertical round tubes. DKU-PDL CHFdatabase[1] was used for this analysis. Four representative CHF data sets at pressureconditions of 1.01, 70, 140, and 200 bar were selected, analyzed and compared toevaluate the effects other than the system pressure on the CHF It has revealed thatthe major variables which inflenced the CHF other than the system pressure (P),were tube diameter (D), mass flux of water (G) and local true mass fraction ofvapor (Xt). The parameters, square root of GXt and square root of D, were alsodetermined to be significant in the parametric trends of the data sets. The results ofthis study have reaffirmed the fesaibility this an advanced generalized CHFcorrelation for uniformly heated vertical round tubes can be found.

균일 가열 수직 원형관에서의 R-12 임계열유속 예측 상관식 개발을 위한 파라미터의 경향성 분석

이지수,이성우,박주용,김준연,심재우 한국공업화학회 2004 응용화학 Vol.8 No.2

The important parameters that have significant effects on the prediction of CHF (Critical Heat Flux) for R-12 (Dichlorodifluoromethane) were investigated. This was a preliminary study for a R-12 CHF correlation in uniformly heated vertical round tubes. Experimental data of Celata [1], Green and Stevens [2], Groenveld [3], Ilic [4], Katto [5], Merilo and Ahmad [6] and Stevens and Miles [7] were used for this analysis. Four representative CHF data sets at pressure condition of 9, 15, 19, and 27 bar were selected, analyzed, and compared to evaluate the effects other than the system pressure on the CHF were tube diameter (D), mass flux of water (G), and local true mass fraction of vapor (X_(t)). The results of this study have reaffirmed the feasibility that an advanced R-12 CHF correlation for uniformly heated vertical round tubes can be found.

섬유상 활성탄에서 페놀계 유도체의 속도흡착특성

이지수,김지민,박주용,이성우,심재우 한국공업화학회 2004 응용화학 Vol.8 No.1

Adsorption characteristics of phenolic compounds by activated carbon fiber have been investigated. Accurate description of kinetic adsorption that can predict the behavior of adsorption equipment it very important in many industrial areas, particularly in environmental applications. In this study, adsorption behavior of phenolic compounds was predicted by the use of Freundlich and Langmuir isothermal adsorption equation. In addition, a two parameter curve fit was used for the comparison. The equilibrium kinetic constant was predicted by Langmuir equation and maximum amount of adsorption was obtained from each isothermal equation. About 40% of substrates were removed within 5 minutes from the initial state of adsorption.

동박적층판 구조에 대한 냉각효율의 예측

이지수,김지민,박주용,이성우,심재우 한국공업화학회 2004 응용화학 Vol.8 No.1

To produce high quality PCB (Printed Circuit Board). CCL (Copper Clad Laminate) that can result in uniform quality is very important. Research and studying the temperature distribution and stress analysis within CCL may not be sufficient. In this study, the temperature distribution of CCL with a separator construction was measured and it was compared with a simulation result. It was found that the separator thickness influenced temperature distribution within CCl. The application of separator was the most effective means of enhancing cooling performance and laminated in a copper-steel-copper separator was effective in uniform cooling.

디자인 경영의 새로운 틀과 한국 기업에 디자인 경영을 적용하기 위한 3가지 추가 요구 사항 : 경험 디자인, 협업, 시행착오

( Joo Jaewoo(주저자) ),( Lee Annie(공동저자) ),( Hee Jean(공동저자) ),( Park Jung Ho(공동저자) ),( Joo Jaewoo(교신저자) ) 디자인융복합학회 2018 디자인융복합연구 Vol.17 No.6

The present research has two objectives. First, we introduce a new framework of design management proposed by Heather Fraser, the Director of Rotman Designworks. It comprises three gears: (1) user understanding, (2) concept visualization, and (3) strategic business design. Second, we investigate the key requirements that are necessary to apply the new framework to Korean companies. We collected fifty reports about the five special lectures from a new product development course at a university in Korea. These lectures were given by three designers and two product managers. We used interpretative analysis and followed three process of qualitative analysis of transcription, coding, and theme discovery. We derived specific requirements for applying design management to Korean companies: (1) experience design, (2) collaboration, and (3) trial and error. We introduced a novel design management framework and clarified the requirements how to successfully apply it to Korean companies. These findings imply that, firstly, executives and practitioners need to improve mutual communication and, secondly, corporations and agencies respect each other in their partner relationships.

Quantum Secure Communication via a W State

Jaewoo Joo,박영재,Inbo Kim,Jingak Jang,이진형 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.4

Based on pair-wise entangled W states, we propose three variant protocols for quantum secure communication, i.e., quantum key distribution, partial quantum secret sharing, and their synthesis. By synthesis, we mean that both quantum key distribution and partial quantum secret sharing are executed in a single protocol. For these protocols, we discuss how to detect eavesdropping, including an intercept-resend attack by an eavesdropper.