충전층에서의 국부유효열전도율에 관한 실험적 연구

이종수,양한주,최국광,서정윤,Lee J.S,Yang H.J,Choi K.K,Seo J.Y 대한설비공학회 1987 설비저널 Vol.16 No.1

In this paper, the local effective thermal conductivities and calculated by using the actual temperature distribution in packed bed. The variations of these are investigated for radius and air stream direction, flow rate and particle diameter. The resulting local effective thermal conductivi-ties are classified in the inner zone of bed and vicinity zone of the wall surface. Also these are related to dimensionless axial direction position, radius direction position, and particle diameter and Reynolds number which uses particle diameter as the characteristic length. If these correla-tions are represented by function, the equation is showed in Eq. (3-4). This equation is well satisfied with experimental results within $\pm25\%.$

Al-Cu-Li-X (In , Be) 합금의 기계적 성질에 미치는 저융점상의 영향

이종수,이승호,김석원,우기도 ( J . S . Lee,S . H . Lee,S . W . Kim,K . D . Woo ) 한국열처리공학회 1995 熱處理工學會誌 Vol.8 No.4

The purpose of this study was to examine the effects of low melting point phase(LMPP) on mechanical properties in the Al-Cu-Li-X(In, Be) alloys. This study was performed by the differential scanning calorimetry(DSC), the transmission electron microscope(TEM), hardness test, tensile test and notch tensile test. The shape of LMPP in the specimens homogenized at 570℃ was film type due to remelting at grain boundary during homogenization. Low melting point phases had no effects on mechanical properties in the aging treated materials, because the density of LMPPs was low. Mechanical properties of the aging treated materials were affected by the density of matrix precipitation phases and grain sizes. For the In or In, Be added Al-Cu-Li alloys, the optimum solution treatment temperature was 550℃. The strength of Al-Cu-Li-In-Be T_6 treated alloy was higher than that of 2090-T_8 alloy.

사각(四角) 충돌수분류(衝突水噴流)의 열전달증진(熱傳達增進)에 관(關)한 연구(硏究)

박성연,이종수,엄기호,서정민,Park, S.Y.,Lee, J.S.,Ohm, K.C.,Seo, J.Y. 대한설비공학회 1991 설비공학 논문집 Vol.3 No.1

The purpose of this study is an augmentation of heat transfer in the case of upward rectangular impinging water jet system. The variables of this study are nozzle-to-heated surface distance, jet velocity and supplementary water height. Optimum heights of supplementary water which augment the heat transfer rate are S/B=2 for H/B=30 and S/B=I for H/B=40, 50. On the Y-direction of nozzle, there exhibits the secondary peak of heat transfer coefficient when supplementary water is not used, however using the supplementary water, it does not exhibits. In the case of using supplementary water, heat transfer coefficient increases not only in stagnation region but also in wall jet region.

CPU 기반 장치에서 효율적인 딥러닝 추론을 위한 컨볼루션 신경망의 가속 방법의 성능 비교

박상수(Sang-Soo Park),정기석(Ki-Seok Chung) 한국통신학회 2019 한국통신학회 학술대회논문집 Vol.2019 No.1

상이한 초미세립 구조를 갖는 OFHC Cu의 연성에 영향을 미치는 요소인자

박이주(L. J. Park),감형원(H. W. Kim),이종수(C. S. Lee),황시우(S. W. Hwang),박경태(K.-T.Park) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.5

Tensile ductility of OFHC Cu with the different ultrafine grained (UFO) structures, which were fabricated by the different routes of equal channel angular pressing (ECAP), was associated in detail with the microstructural characteristics developed by ECAP. OFHC Cu having the lamellar and equiaxed UFO structures was prepared by ECAP of routes A and Bc respectively up to 8 and 16 passes. Their microstructures were closely examined by transmission electron microscopy and orientation image mapping. Tensile tests at room temperature were conduced on the ECAPed samples under the quasi- static condition of 10?³ s?¹ and 1 s?¹. Uniform elongation of the lamellar UFO samples decreased with increasing the ECAP passage while both uniform and total elongations of the equiaxed UFO samples increased. In the case of route A producing the lamellar UFO structure, the fractions of high angle grain boundaries and grains less than 0.5 ㎛ increased significantly but an analysis revealed that the dislocation free length decreased with increasing the ECAP passage. For route Be resulting in the equiaxed UFO structure, the fraction of high angle grain boundaries increased but the grain size distribution and the dislocation free length remained nearly unchanged with increasing the ECAP passage. From the present experiments and analyses, it was found that tensile ductility of lamellar UFO OFHC Cu is primarily controlled by the dislocation free length and that of the equiaxed one is mainly dependent on the fraction of high angle grain boundaries.

연직상향(鉛直上向) 사각충돌수분류(四角衝突水噴流)의 포화비등 열전달에 관한 연구

이종수,엄기찬,서정윤,Lee, J.S.,Ohm, K.C.,Seo, J.Y. 대한설비공학회 1991 설비공학 논문집 Vol.3 No.5

The purpose of this investigation was to characterize nucleate boiling and burn-out heat flux for rectangular free jet with saturated water impinging perpendicularly and upward against a flat uniform heat flux surface. Heat flux measured for Reynolds number based on rectangular nozzle width and for aspect ratio. The result of nucleate boiling heat transfer was presented nondimensional experimental equation including Nusselt, Boiling, Subcooling, Reynolds and Weber number. The effect of aspect ratio of heated surface in the burn-out heat flux had not appeared distinctly. But for the same aspect ratio, burn-out heat flux increased linearly with increment of nozzle exit velocity.

회전 원추형 마늘 쪽분리기 개발에 관한 연구 (II) - 원추 간극의 영향 -

이종수,김기복,Lee, J.S.,Kim, K.B. 한국농업기계학회 2007 바이오시스템공학 Vol.32 No.2

The purpose of this study is to find optimal conditions for various outlet clearances of prototype garlic clove separator with a rotating cone in the constant inlet clearance and cone height. Optimal outlet clearance from medium to small size garlics was 25 mm at the $200{\sim}400rpm$. For large garlic, optimal outlet clearances of Namdo and Uiseong garlic were 34 mm and 37 mm, respectively, in the range of $300{\sim}400rpm$. The proportion of garlic separation was over 95% for all quality of garlics. The proportions of damaged garlics at 25 mm and 28 mm outlet clearances were below 5% and below 10%, respectively. Therefore, in order to maintain high performance of garlic separation for the various varieties and qualities, the rotating cone type separator should be designed with cone speed ranges of $200{\sim}400rpm$ and the outlet clearance ranges of $25{\sim}37 mm$. The outlet clearance of the separator should be easily controlled within those ranges.

Anisotropic Magnetization and Charge Density Wave in a Na0.78CoO2 Single Crystal

이종수,J. B. Peng,S. M. Lee,C. T. Lin 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2

Single crystals of γ-Na0.78CoO2 were grown using the floating zone method. The static magnetic susceptibility M/H(T) of Na0.78CoO2 showed significant anisotropic behavior for different crystal orientations of H ∥ (ab) and H ∥ (c). While (M/H)ab(T) for a magnetic field H= 1 T in an ab-plane followed the Curie-Weiss law at high temperatures (T ≥ 100 K), (M/H)c(T) for H ∥ c-axis deviated from Curie-Weiss behavior, which may be understood by using phonon localization from strong electron-phonon coupling. The impurity spin-1/2 effect, dressed by spin fluctuation, was significant at low temperatures (T ≤ 30 K) for both field orientations of H ∥ (ab) and H ∥ (c). The electrical resistivity ρ(T) of Na0.78CoO2 showed a clear metallic character down to 16 K, with a weak increase in the resistivity ρ(T) at low temperatures T ≤ 16 K). The gap-like behavior of ρ(T) was insensitive to applied magnetic fields up to 7 T, which indicates a non-degenerate charge gap. The electrical conductivity σ(T) followed the density wave behavior with a small energy gap (0.64 meV) at low temperatures. We discussed the electrical resistivity ρ(T)$ and the anisotropic M/H(T) behavior of Na0.78CoO2 in terms of the charge density wave and a strong electron-phonon interaction. Single crystals of γ-Na0.78CoO2 were grown using the floating zone method. The static magnetic susceptibility M/H(T) of Na0.78CoO2 showed significant anisotropic behavior for different crystal orientations of H ∥ (ab) and H ∥ (c). While (M/H)ab(T) for a magnetic field H= 1 T in an ab-plane followed the Curie-Weiss law at high temperatures (T ≥ 100 K), (M/H)c(T) for H ∥ c-axis deviated from Curie-Weiss behavior, which may be understood by using phonon localization from strong electron-phonon coupling. The impurity spin-1/2 effect, dressed by spin fluctuation, was significant at low temperatures (T ≤ 30 K) for both field orientations of H ∥ (ab) and H ∥ (c). The electrical resistivity ρ(T) of Na0.78CoO2 showed a clear metallic character down to 16 K, with a weak increase in the resistivity ρ(T) at low temperatures T ≤ 16 K). The gap-like behavior of ρ(T) was insensitive to applied magnetic fields up to 7 T, which indicates a non-degenerate charge gap. The electrical conductivity σ(T) followed the density wave behavior with a small energy gap (0.64 meV) at low temperatures. We discussed the electrical resistivity ρ(T)$ and the anisotropic M/H(T) behavior of Na0.78CoO2 in terms of the charge density wave and a strong electron-phonon interaction.

衝突水噴流에 의한 凹凸面上의 熱傳達에 관한 硏究

엄기찬(K.C.Ohm),이종수(J.S.Lee),서정윤(J.Y.Seo) 한국태양에너지학회 1994 한국태양에너지학회 논문집 Vol.14 No.1

본 연구에서는 내부곡선이 정현곡선형으로 된 노즐(출구형 : 6㎜)로부터 상향으로 반원통의 내면 및 외면(직경 : 각각 40㎜, 50㎜, 60㎜, 70㎜의 4종류)에 충돌시켜 그 열전달 특성을 구명하고, 동시에 보조수를 사용하여 열전달 촉진현상을 실험적으로 구명하였다. 그 결과 다음과 같은 결론을 얻었다.<br/> 반원통의 내외면 공히 국소열전달계수는 정체점으로부터 벽면을 따라 단순 감소하는데, 요면의 경우는 보조수를 사용하지 않는 경우에는 정체점으로부터 벽면을 따라 노즐직경의 10배 이후의 영역에서 거의 균일한 분포를 갖는다. 최대 열전달계수는 보조수층 높이가 노즐직경의 1배의 조건에서 나타나며, 凸面에 비하여 凹面의 경우에 열전달계수가 크다. 평균열전달계수는 전열면직경/노즐직경의 비가 작을수록 크게 나타나고 있다. Experiments are performed to study heat transfer processes over a convex and concave surface. A single water jet issuing from nozzle and a water jet accompanied by supplementary water impinge normally on the convex side or the concave side of a heated semi-cylindrical surface. The local heat transfer Nusselt number along the surface is measured. In the experiment, the Reynolds number ranges from 24000 to 54000, and the supplementary water height to nozzle diameter ratio S/D is from 0 to 3.<br/> The local heat transfer and the average heat transfer are maximum value in the condition of S/D=1 and them of concave surface are larger than those of convex surface. The average heat transfer increases with decreasing d/D. Correlations of both the stagnation point and the average Nusselt number over the curved surface, which account for the surface curvature effect, are presented.

Ti-13Nb-13Zr 합금의 저 변형량에서 초미세 결정립 형성 및 기계적 적합성 향상

박찬희(C. H. Park),염종택(J. T. Yeom),전영수(Y. S. Chun),이종수(C. S. Lee) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.10

Microstructural evolution of alpha and beta phases during dynamic globularization of near-beta Ti-13Nb-13Zr alloy was investigated to determine the optimum processing conditions. The submicrocrystalline alloy sheet with ~80% of high-angle grain boundaries was produced utilizing dynamic globularization at temperature of 600℃, equivalent strain rate of 10<SUP>-1</SUP> s<SUP>-1</SUP> and strain of 1.4. The refined structure with the grain size of ~0.4 ㎛ showed 25-60% enhanced mechanical compatibility as compared to those of the conventional mill-annealed or solution treated and aged microstructures.