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A study on electroreflectance in undoped n-GaAs (불순물이 첨가되지 않은 n-GaAs에서의 Electroreflectance에 관한 연구)

  • 김인수;김근형;손정식;이철욱;배인호;김상기
    • Journal of the Korean Vacuum Society
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    • v.6 no.2
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    • pp.136-142
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    • 1997
  • An/n-GaAs(100) Schottky barrier diode has been investigated by using electoreflectance(ER). From the observed Franz-Keldysh oscillatins(FKO), the internal electric field(Ei) of the sample is $5.76\times 10^{4}$V/cm at 300 K. As the modulation voltage($V_{ac}$) IS changed, the line shape of ER signal does not change but its amplitude various linerly. For increasing forward and reverse dc bias boltage($V_{bias}$), the amplitude of ER signal decreases. The internal electric field decreased from $19.3\times 10^4\sim4.39\times10^4$V/cm as $V_{bias}$ INCREASES FROM -5.0 V TO 0.6 V. For Au/n-GaAs the valve of built-in voltage($V_{bi}$) determined from the plot of $V_{bias}$ versus $E_i^2$ is 0.70 V. This value agrees with that observed in the plot of $V_{bias}$ versus amplitude of FKO peak. In addition, the carrier concentraion(N) and potential barrier($\Phi$) of the sample at 300 K are found to be about $2.4\times 10^{16}\textrm{cm}^{-3}$ and 0.78 eV, respectively.

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Comparison of Methods Predicting VS30 from Shallow VS Profiles and Suggestion of Optimized Coefficients (얕은 심도 VS주상도를 활용한 VS30 예측 방법론 비교 및 최적 계수 제시)

  • Choi, Inhyeok;Kwak, Dongyoup
    • Journal of the Korean Geotechnical Society
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    • v.36 no.3
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    • pp.15-23
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    • 2020
  • Ground motion models predicting intensity measures on surface use a time-averaged shear wave velocity, VS30, as a key variable simulating site effect. The VS30 can be directly estimated from VS profiles if the profile depth (z) is greater than or equal to 30 m. However, some sites have VS profiles with z < 30 m. In this case VS30 can be predicted using extension models. This study proposes new coefficient sets for existing prediction equations using 297 Korea VS profiles. We have collected VS profiles from KMA and Geoinfo database. Fitting six existing methods to data, we suggest new coefficients for each method and evaluate their performance. It turns out that if z ≥ 15 m, the standard deviation (σ) of residual in log10 is 0.061, which indicates that the estimated VS30 is nearly accurate. If z < 15 m, the σ keeps increasing up to 0.1 for z = 5 m, so we caution the use of models at very low z. Nonetheless, we recommend investigating up to 30 m depth for VS30 calculation if possible.

Multi-Channel MAC Protocol Based on V2I/V2V Collaboration in VANET (VANET에서 V2I/V2V 협력 기반 멀티채널 MAC 프로토콜)

  • Heo, Sung-Man;Yoo, Sang-Jo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.1
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    • pp.96-107
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    • 2015
  • VANET technologies provide real-time traffic information for mitigating traffic jam and preventing traffic accidents, as well as in-vehicle infotainment service through Telematics/Intelligent Transportation System (ITS). Due to the rapid increasement of various requirements, the vehicle communication with a limited resource and the fixed frame architecture of the conventional techniques is limited to provide an efficient communication service. Therefore, a new flexible operation depending on the surrounding situation information is required that needs an adaptive design of the network architecture and protocol for efficiently predicting, distributing and sharing the context-aware information. In this paper, Vehicle-to-Infrastructure (V2I) based on communication between vehicle and a Road Side Units (RSU) and Vehicle-to-Vehicle (V2V) based on communication between vehicles are effectively combined in a new MAC architecture and V2I and V2V vehicles collaborate in management. As a result, many vehicles and RSU can use more efficiently the resource and send data rapidly. The simulation results show that the proposed method can achieve high resource utilization in accordance. Also we can find out the optimal transmission relay time and 2nd relay vehicle selection probability value to spread out V2V/V2I collaborative schedule message rapidly.

Effect of Coagulants on the Quality of Soybean Curd Added With Cow's Milk (응고제가 우유 첨가 두부의 품질에 미치는 영향)

  • Kim, Tae-Young;Kim, Joong-Man;Cho, Nam-Jun
    • Applied Biological Chemistry
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    • v.37 no.5
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    • pp.370-378
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    • 1994
  • Soybean curd added with 40% of cow’s milk was prepared with eight coagulants such as calcium acetate, calcium lactate, calcium chloride, calcium sulfate, magnesium chloride, glucono-delta lactone (GDL), acetic acid and lactic acid. The curd products were evaluated by the chemical composition, coprecipitation porperties, mineral content, yield, color and textural characteristics. The lowest concentrations for protein coprepitation were 0.3% (v/v) for calcium salts, 0.4% (v/v) for magnesium chloride, 0.2% (v/v) for organic acids. Turbidity and crude protein of whey were markedly decreased at these concentrations. The optimal concentrations of coagualnts used for soybean curd preperation were 1.2% (v/v) for calcium acetate, calcium sulfate and calcium lactate, 1.0% (v/v) for calcium chloride and GDL, 0.8% (v/v) for magnesium chloride and lactic acid, 0.6% (v/v) for acetic acid. It was observed that of the eight coagulants tested, calcium chloride provided a satisfactory curd in quality. Calcium content of soybean curds by the calcium salt coagulants was higher than that by organic acid coagulants. Through the examination on the textural properties by a texturemeter was found out that acetic acid treated soybean curd among the organic acids, calcium salts and magnesium chloride treated curds had very high hardness value. All the curd products prepared in this experiment had a pale yellow color as affected by the value of L (lightness), a (redness) and b (yellowness). Although the colorimetric readings showed that the soybean curds prepared with the organic acids had higher L value but lower a and b value in comparison to calcium salts and magnesium chloride treated curds.

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Viability of Vibrio parahaemolyticus and V. vulnificus isolated from human in cultured olive flounder (Paralichthys olivaceus) (Vibrio parahaemolyticus와 V. vulnificus 사람 분리균의 넙치, Paralichthys olivaceus에서의 생존율)

  • Im, Su Yeon;Kim, Eunheui
    • Journal of fish pathology
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    • v.35 no.1
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    • pp.57-63
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    • 2022
  • Vibrio parahaemolyticus and V. vulnificus are known to be infected to human via fisheries products. Therefore, food safety of fisheries products is important for public health and fish industry. This paper was conducted to know how well these human isolates can survive in olive flounder (Paralichthys olivaceus). The growth of V. parahaemolyticus and V. vulnificus showed about 50~60% reduced rates at 25℃ than at 37℃ and did not show any differences according to NaCl concentration of media except the increasing in the growth of V. vulnificus in medium containing 3% NaCl. Artificial infection of 1×106 CFU/fish was carried out to confirm the sensitivity of olive flounder against V. parahaemolyticus and V. vulnificus. After 1 week from injection, no fish was dead. To evaluate nonspecific defense of olive flounder against V. parahaemolyticus and V. vulnificus, the antibacterial potency of serum and epidermal mucus were tested. The number of the vibrios exposed to serum obtained from olive flounder significantly decreased after 3 hours, and epidermal mucus showed decrease of the bacteria over than 90% until 12 hours from exposure. Phagocytosis of head kidney leucocytes of healthy olive flounder against V. parahaemolyticus and V. vulnificus showed in over 70% of leucocytes at the 2 hours. Therefore, cultured olive flounder only as vehicle for human pathogen in environmental water is well developed its antibacterial potency against human pathogens, so the viability of V. parahaemolyticus and V. vulnificus in cultured olive flounder was considered very low.

The Basic Study on 800kV GIS Development (800kV GIS 개발을 위한 기본연구)

  • Kim, J.B.;Yang, D.I.;Song, W.P.;Lee, C.H.;Noh, C.W.
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1341-1343
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    • 1995
  • The maximum transmission voltage in our country is going to change 345kV into 765kV owing to the increase of Electrical Power Demand and power System Stability. Our company is developing 800kV GIS and 765kV Transformer which are main equipments in 765kV substation. This paper describs the specification on 800kV GIS which we prepared for 800kV 8,000A 50kA GIS development. This specification is supported by Public Standards and Data. And, we are designing the 800kV GIS on this specification and drawing up the 800kV GIS layout for type test.

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TOPOLOGICAL CONJUGACY OF DISJOINT FLOWS ON THE CIRCLE

  • Cieplinski, Krzysztof
    • Bulletin of the Korean Mathematical Society
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    • v.39 no.2
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    • pp.333-346
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    • 2002
  • Let $F={F^v:S^1->S^1,v\in\; V$ and $g={G^v:S^1->S^1,v\in\; V$ be disjoint flows defined on the unit circle $S^1$, that is such flows that each their element either is the identity mapping or has no fixed point ((V, +) is a 2-divisible nontrivial abelian group). The aim of this paper is to give a necessary and sufficient codition for topological conjugacy of disjoint flows i.e., the existence of a homeomorphism $\Gamma:S^1->S^1$ satisfying $$\Gamma\circ\ F^v=G^v\circ\Gamma,\; v\in\; V$$ Moreover, under some further restrictions, we determine all such homeomorphisms.

A SUFFICIENT CONDITION FOR ACYCLIC 5-CHOOSABILITY OF PLANAR GRAPHS WITHOUT 5-CYCLES

  • Sun, Lin
    • Bulletin of the Korean Mathematical Society
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    • v.55 no.2
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    • pp.415-430
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    • 2018
  • A proper vertex coloring of a graph G is acyclic if G contains no bicolored cycle. A graph G is acyclically L-list colorable if for a given list assignment $L=\{L(v):v{\in}V(G)\}$, there exists an acyclic coloring ${\phi}$ of G such that ${\phi}(v){\in}L(v)$ for all $v{\in}V(G)$ A graph G is acyclically k-choosable if G is acyclically L-list colorable for any list assignment with $L(v){\geq}k$ for all $v{\in}V(G)$. Let G be a planar graph without 5-cycles and adjacent 4-cycles. In this article, we prove that G is acyclically 5-choosable if every vertex v in G is incident with at most one i-cycle, $i {\in}\{6,7\}$.

n-ARY $P-H_v$-GROUPS

  • Ghadiri, M.;Waphare, B.N.
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.945-959
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    • 2008
  • n-ary $H_v$-structures is a generalisation of both n-ary structures and $H_v$-structures. A wide class of n-ary $P-H_v$-groups is the n-ary $P-H_v$-groups that is concidered in this paper. In this paper the notion of a normal subgroup of an n-ary $P-H_v$-groups is introduced and the isomorphism theorems for n-ary $P-H_v$-groups are stated and proved. Also some examples and related properties are investigated.

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Clinical Analysis of 102 Cases of Open Heart Surgery (개심수술 102례 의 임상적 고찰)

  • 김형묵
    • Journal of Chest Surgery
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    • v.14 no.3
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    • pp.235-240
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    • 1981
  • A total of 102 patients who had an Open Heart Surgery from April 1976 to July 1981 were reviewed. 55 paeitnts were congenital heart disease and 47 patients were acquired heart disease. Among SS patients of congenital heart disease, 18 T 0 F, 18 V S D, 8 A S D, and each one case of l\ulcorner 0 R V, Truncus arteriosus, Ebstein anomaly, Single ventricle, P D A, P 5, A S D + P 5, E C D, V 5 D + P D A, A - P window, D C R V were noted respectively. In 47 patients of acquired heart disease and one Ebstein patient, 46 prosthetic values were implanted: 17 had M V R, 4 had A V R, 2 had M V R + A V R, and 4 had M V R + T V R and one T V R. The operative mortality was 8.S% in acquired heart disease and 17% in congenital heart disease. The follow up period was between 6 months and 6 years. There were 3 cases of late mortality in acquired heart disease and one case in congenital heart disease.

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