http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
신지영,김민수,노승탁,Shin, J.Y.,Kim, M.S.,Ro, S.T. 대한설비공학회 1996 설비공학 논문집 Vol.8 No.2
Boiling heat transfer coefficients of pure refrigerants(R22, R32, R125, R134a, R290, and R600a) and refrigerant mixtures(R32/R134a and R290/R600a) are measured experimentally and compared with several correlations. Convective boiling term of Chen's correlation predicts experimental data for pure refrigerants fairly well(root-mean-square error of 12.1% for the quality range over 0.2). An analysis of convective boiling heat transfer of refrigerant mixtures is performed for an annular flow to study degradation of heat transfer. Annular flow is the subject of this analysis because a great portion of the evaporator in refrigeration or air conditioning system is known to be in the annular flow regime. Mass transfer effect due to composition difference between liquid and vapor phases, which is considered as a driving force for mass transfer at interface, is included in this analysis. Correction factor $C_F$ is introduced to the correlation for the pure substances through annular flow analysis to apply the correlation to the mixtures. The flow boiling heat transfer coefficients are calculated using the correlation considering nucleate boilling effect in the low quality region and mass transfer effect for nonzazeotropic refrigerant mixtures.
김동섭,신지영,노승탁,Kim, T.S.,Shin, J.Y.,Ro, S.T. 대한설비공학회 1992 설비공학 논문집 Vol.4 No.4
A heat pump system is constructed to evaluate its performance and heat transfer characteristics with mixtures of R22/R142b as working fluids. The heat transfer in the evaporator and the overall performance are measured and analyzed in terms of the compositions and relevant variables. Possibility of capacity modulation by changing composition is observed without degradation of heat transfer coefficients and coefficient of performance. The cooling capacity is varied continuously within 200 percent based on minimum capacity at constant compressor speed. For similar cooling capacity, COP is improved by mixing two refrigerants and shows maximum value at 60% mass fraction of R22. Average heat transfer coefficients of mixtures decrease in comparison with pure refrigerants at similar cooling capacity and mass flow rate. However, the overall heat transfer coefficients decrease moderately. A cycle simulation is performed in order to manifest the advantages of using refrigerant mixtures, considering experimentally observed heat transfer characteristics.
R134a, R152a, R22/142b를 이용한 냉동기의 성능실험
장영수,신지영,노승탁,Chang, Y.S.,Shin, J.Y.,Ro, S.T. 대한설비공학회 1994 설비공학 논문집 Vol.6 No.1
Experiments on the performance of refrigeration system using alternatives to R12 are carried out. The condenser and the evaporator are concentric-tube heat exchangers of counter-flow type and the compressor is driven by a variable speed motor. In this study, R134a, R152a, R22/142b(50 : 50 by mass) are adopted as alternatives to R12. Tests are performed by varying the inlet and outlet temperatures of secondary fluids of evaporator and condenser under the condition of constant compressor speed, degree of superheating and degree of subcooling. Results show that R134a has refrigeration capacity close to that of R12 and requires the greatest compressor power compared with that of others. And the system using R152a shows the best performance from the viewpoint of refrigeration capacity, compressor power and coefficient of performance. R22/142b is superior to R12 in the above points.
R12 및 R22대체냉매의 열역학적 물성치 및 냉동기의 성능비교
장세동,신지영,노승탁,Chang, S.D.,Shin, J.Y.,Ro, S.T. 대한설비공학회 1993 설비공학 논문집 Vol.5 No.1
Thermodynamic properties of alternatives for R12 and R22 were estimated and performances of refrigerating cycle using these refrigerants were compared. In this study, we adopt R134a, R22/R142b, R22/R152a, R22/R152a/R124 as alternatives for R12 and R32/R134a for R22. Thermodynamic properties of these refrigerants were estimated using modified CSD equation of state. Cycle simulations of the refrigerating system considering heat source were carried out in order to compare the performance of the system. R134a shows relatively lower COP than R12 but very similar VCR. R22/R142b(50/50 mass fraction), R22/R152a(10/90), R22/R152a/R124(30/25/45) are good for the substitutes of R12 and R32/R134a(30/70) is appropriate for that of R22 in view of COP and VCR.
흑연 표면에 형성된 dipyrromethene-trimer 분자의 저차원 나노구조의 주사 터널링 현미경 연구
손승배,이수진,한재량,신지영,Son, S.B.,Lee, S.J.,Hahn, J.R.,Shin, J.Y.,Dolphin, D. 한국진공학회 2008 Applied Science and Convergence Technology Vol.17 No.5
Dipyrromethene 유도체 분자 중 하나인 삼각형 모양의 Co-DPM 거대분자 (Co-DPM-trimer, Fig. 1)를 이용하여 흑연 표면에서 다양한 저차원 분자 나노구조를 형성할 수 있었으며, 이를 주사 터널링 현미경(scanning tunneling microscope)으로 관찰하였다. Co-DPM-trimer 분자를 $CH_2Cl_2$ 용매에 녹여 흑연 표면에 뿌리면, 용매가 증발되며 그 동안 표면에 분자 나노구조가 형성된다. 본 연구에서는 다양한 두께의 긴 1차원 분자선과 2차원 구조인 육각형 패턴을 관찰하였다. 1차원 분자선과 2차원 육각형 패턴의 높낮이 및 구조를 분석한 결과, 1차원 분자선의 경우 흑연 표면에 'edge-on'정렬로 연속된 $\pi-\pi$ stacking 상호작용에 의해서, 그리고 육각형 패턴 구조는 'face-on'정렬을 통해서 형성된 것으로 보인다. We have investigated the low-dimensional nanostructures produced by adsorption of triangular Co coplexed dipyrromethane(DPM-trimer, Fig. 1) on graphite surface by using scanning tunneling microscope. DPM-trimer deposition on the graphite surface leads to the formation of long 1-D molecular wires and 2-D hexagonal patterns. We analyzed the heights and structures of 1-D molecular wires and 2-D hexagonal patterns. The 1-D molecular wires were formed 'edge-on' alignments on graphite surface result of continuos $\pi-\pi$ stacking interactions. The other case of 2-D hexagonal patterns were formed 'face-on' alignments on graphite surface.