CBD 방법에 의한 CdS 박막의 성장과 광전도 특성

황광준,이상열,유상하,서상석,문종대,신영진,정태수,신현길,김택성,송정훈,유기수 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

Chemical bath deposition 방법으로 다결정 CdS 박막을 세라믹 기판 위에 성장시킨 다음 온도를 변화시켜 열처리하고 X-선 회절무늬를 측정하여 결정구조를 밝혔다. 550℃로 열처리한 시료의 경우 X-선 회절무늬로 부터 외삽법에 의해 a_。와 c_。는 각각 4.1364 Å과 6.7129 Å인 육방정계임을 알았다. 이 때 낱알크기는 약 0.35㎛이었다. Van der Pauw 방법으로 Hall 효과를 측정하여 운반자 농도와 이동도의 온도의존성을 연구하였다. 이동도는 33 K 에서 150 K 까지는 압전산란에 의하여, 150 K 에서 293 K 까지는 극성광학산란에 의하여 감소하는 경향이 나타냈다. 광전도 셀의 특성으로 스텍트럼 응답, 감도(γ), 최대허용소비전력 및 응답 시간을 측정하였다. Polycrystalline CdS thin films were grown on creamic substrate using a chemical bath deposition method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdS polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdS samples annealed in N_2 gas at 550℃ it was found hexagonal structure whose lattice constants a_o and c_o were 4.1364 Å and 6.7120Å, respectively. Its grain size was about 0.35 ㎛. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33K and 150K and by polar optical scattering at temperature range of 150K and 293K. We measured also spectral response, sensitivity (γ), maximum allowable power dissipation and response time on these samples.

The partitioned-layer index: Answering monotone top-k queries using the convex skyline and partitioning-merging technique

Heo, J.S.,Whang, K.Y.,Kim, M.S.,Kim, Y.R.,Song, I.Y. North-Holland [etc ; Elsevier Science Ltd 2009 Information sciences Vol.179 No.19

A top-k query returns k tuples with the highest (or the lowest) scores from a relation. The score is computed by combining the values of one or more attributes. We focus on top-k queries having monotone linear score functions. Layer-based methods are well-known techniques for top-k query processing. These methods construct a database as a single list of layers. Here, the ith layer has the tuples that can be the top-i tuple. Thus, these methods answer top-k queries by reading at most k layers. Query performance, however, is poor when the number of tuples in each layer (simply, the layer size) is large. In this paper, we propose a new layer-ordering method, called the Partitioned-Layer Index (simply, the PL Index), that significantly improves query performance by reducing the layer size. The PL Index uses the notion of partitioning, which constructs a database as multiple sublayer lists instead of a single layer list subsequently reducing the layer size. The PL Index also uses the convex skyline, which is a subset of the skyline, to construct a sublayer to further reduce the layer size. The PL Index has the following desired properties. The query performance of the PL Index is quite insensitive to the weights of attributes (called the preference vector) of the score function and is approximately linear in the value of k. The PL Index is capable of tuning query performance for the most frequently used value of k by controlling the number of sublayer lists. Experimental results using synthetic and real data sets show that the query performance of the PL Index significantly outperforms existing methods except for small values of k (say, k=<9).

Chemical Bath Deposition 방법으로 제작한 CdSe 박막의 특성

홍광준,이상열,유상하,서상석,문종대,신영진,정태수,신현길,김택성,송정훈,유기수 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

Chemical bath deposition 방법으로 다결정 CdSe 박막을 세라믹 기판 위에 성장시킨 다음 온도를 변화시켜 열처리하고 X-선 회절무늬를 측정하여 결정구조를 밝혔다. 450℃로 열처리한 시료가 X-선 회절무늬로 부터 외삽법에 의해 a_o와 c_o 는 각각 4.302 Å과 7.014 Å인 육방정계임을 알았다. 이 때 낱알크기는 약 0.3㎛이었다. Van der Pauw 방법으로 Hall 효과를 측정하여 운반자 농도와 이동도의 온도의존성을 연구하였다. 이동도는 33 K 에서 200 K 까지는 압전산란에 의하여, 200 k 에서 293 K 까지는 극성광학산란에 의하여 감소하는 경향이 나타냈다. 광전도 셀의 특성으로 스텍트럼 응답, 감도(γ), 최대허용소비전력 및 응답 시간을 측정하였다. Polycrystalline CdSe thin films were grown on creamic substrate using a chemical bath deposition (CBD) method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in N_2 gas at 450℃ it was found hexagonal structure whose lattice parameters a_o and c_o were 4.302 Å and 7.014 Å, respectively. It grain size was about 0.3 ㎛. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33 K and 200 K, and by polar optical potical scattering at temperature range of 200 K and 293 K. We measured also spectral response, sensitivily (γ), maximum allowable power dissipation and response time on these samples.

염료공장의 톨루이딘 슬폰산 공정폐수와 종합폐수의 생물학적 처리

송승구,주승팔,이민규,박태주 한국화학공학회 1988 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.26 No.2

염료공장의 고농도 유기성 폐수인 Toluidine Sulfonic Acid(TSA) 공정폐수의 희석처리도 실험과 TSA 공정폐수와 공장전체 폐수를 혼합한 종합폐수의 처리도 실험을 행하였다. TSA 공정폐수의 응집처리는 pH가 6.5일 때 황산알루미늄 300㎎/ℓ 주입으로 약 40%의 COD 제거 효과를 나타내었다. TSA 공정폐수와 종합폐수를 완전혼합 활성슬럿지 공법으로 처리한 결과, 폭기시간 86시간 이상, F/M비 0.074㎏BOD/㎏MLSS/day 이하에서 68% 및 88% 이상의 COD 및 BOD 제거율을 얻었으며, 이 실험조건에서 동력학적 계수, k, K_s, Y, K_d의 값은 각각 0.174-0.453day^(-1), 68.8-152.6㎎/ℓ, 0.445-0.653 및 0.0022-0.0075day^(-1)의 범위로 나타났다. An laboratory-scale experiment was carried out to determine the characteristics and treatability of toluidine sulfonic acid (TSA) process wastewater and combined wastewater in a dye plant. Chemical treatment with aluminium sulfate, 300 ㎎/ℓ at pH 6.5 showed about 40% COD removal efficiency. With a completely-mixed-activated-sludge (CMAS) unit, the removal efficiencies of BOD_5 and COD were achieved more than 88% and 66%, respectively, at aeration time longer than 86 hours, that corresponded to the F/M ratio below 0.074 ㎏BOD/㎏MLSS/day. Design parameters, such as k, K_s, Y and K_d applied to CMAS mathematical equations were found as the range of 0.174-0.452 day^(-1), 68.8-152.6 ㎎/ℓ, 0.445-0.653 and 0.0022-0.0075 day^(-1), respectively.

Search for the H Dibaryon in (K^-,K^+) Reactions

Aoki, S.,Chung, K.S.,Park, I.G.,Song, J. S. 慶尙大學校 기초과학연구소 1990 基礎科學硏究所報 Vol.6 No.-

We have studied (K^-,K^+) reactions from an emulsion target. The S=-2H dibaryon has been searched for by the analysis of the K^+ momentum spectrum together with emulsion data. No evidence of H production was observed in the mass range of 1.90-2.16 GeV/C^2. Upper limits for the production cross section of the H are (0.2-0.6)% of that for the quasifree≡^- production at the 90% confidence level.

K-LAN 각 PSDN 연결을 위한 gateway machine의 구현에 관한 연구

송병권(B.K.Song),변준범(J.B.Byun),이광휘(K.H.Lee),안순신(S.S.An),최성수(S.S.Choi),신영석(Y.S.Shin),정광수(K.S.Chung),최양희(Y.H.Choi) 대한전자공학회 1986 대한전자공학회 학술대회 Vol.1986 No.6

소산률방정식의 개선을 통한 저레이놀즈수 k-ε모형의 개발

송경,유근종,조강래 창원대학교 공작기계기술연구센터 1999 연구업적집 Vol.1 No.1

Recent methods of developing k-εmodel have been carried out with the aid of DNS data to include the effect of near wall. Though these methods opened new way of turbulence modelings, newly developed turbulence models of its kind can't predict properly the turbulent flows with various Reynolds numbers and various geometric conditions. As a remedy for these shortcomings, new k.-ε model is presented here which includes the improved dissipation rate equation and the improved damping function for eddy viscosity model. The new dissipation rate equation was modeled based on the energy spectrum and magnitude analysis The damping function for eddy viscosity was also formulated on the ground of distribution of distribution of dissipation rate length scales near a wall and the DNS data. The new K-ε model was applied to the fully developed turbulent flows in a channel and a pipe with a wide range of Reynolds numbers. prediction results show that the present model represents properly the turbulence properties in all turbulent regions over a wide range of Reynolds numbers.

Synthesis and Thermoelectric Properties of Ce1−z Pr z Fe4−x Co x Sb12 Skutterudites

Song, K. M.,Shin, D. K.,Jang, K. W.,Choi, S. M.,Lee, S.,Seo, W. S.,Kim, I. H. Springer Science + Business Media 2017 Journal of electronic materials Vol.46 No.5

<P>p-Type Ce1-z Pr (z) Fe4-x Co (x) Sb-12 skutterudites were prepared by encapsulated melting, quenching, annealing, and hot pressing. While the skutterudite phase was successfully synthesized, a small amount of the secondary phase (FeSb2) was observed. According to the scanning electron microscope analysis, (Ce,Pr)Sb-2 phases were also observed for Co-substituted specimens (x = 0.5). The electrical conductivity decreased with increasing temperature, implying a degenerate semiconductor behavior, and also decreased with increasing Co contents. All specimens showed p-type characteristics having positive signs of the Hall coefficient and the Seebeck coefficient. The Seebeck coefficient increased with increasing temperature and reached a maximum value at 823 K. The power factor (PF) increased with decreasing Co content and Ce0.75Pr0.25 Fe4Sb12 showed a peak value of PF = 3.2 mW m(-1) K-2 at 823 K. The electronic thermal conductivity decreased with increasing Co contents and the lattice thermal conductivity decreased with decreasing Ce and Co contents at high temperature. The thermal conductivity increased at temperatures above 623 K due to bipolar conduction. The dimensionless figurea of pound merit (ZT) showed a maximum value of ZT = 0.84 at 823 K for Ce0.25Pr0.75Fe4Sb12.</P>

Ferromagnetic Behavior above Room Temperature of Fe-Ion-Implanted ZnO

송영열,K.S Park,K.W Lee,유성초,신상원,강희재,황정남,D.V Son,J.H Lee,J.H Song 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.6

Zinc-oxide (0001) single crystals with a 0.5 mm thickness were prepared, and then 80 keV Fe ions with a dose of 3 $\times$ 10$^{16}$ ions/cm$^{2}$ were implanted into the ZnO single crystals at 350 $^\circ$C. The implanted samples were post-annealed at 700, 800 and 900 $^\circ$C by rapid thermal annealing in an N$_{2}$ atmosphere for 5 min to remove the ion-implantation damage. The structure and the magnetic properties of Fe-ion-implanted ZnO were investigated by using X-ray diffraction and a superconducting quantum interference device magnetometer. The carrier transport properties were measured in the range from 5 K to 300 K. The X-ray diffraction results showed an island peak near 37 $^\circ$C, which was identified as ZnO$_{2}$. The magnetization curve showed hysteresis loops at 5 K in the samples annealed at 700 and 800 $^\circ$C, showing ferromagnetism. Hysteresis loops were observed at 300 K in the samples annealed at 700 $^\circ$C. The temperature dependence of the magnetization was taken in field cooling (FC) and zero field cooling (ZFC) in the samples annealed at 700 $^\circ$C. The difference magnetization ($\Delta$\textit{M}) between the FC and the ZFC magnetizations did not converge to a zero value even at 340 K, showing ferromagnetism above room temperature. The magnetoresistance (MR) curve showed negative curvature up to 150 K which could be explained with the delocalized \textit{d} state of ZnO implanted with Fe ions

적외선처리 사료의 반추위내 분해율 및 하부 소화기관에서의 소화율 평가

송만강(Man K . Song),죤 케넬리(John J . Kennelly) 한국영양사료학회 1996 韓國營養飼料學會誌 Vol.20 No.5