• Title/Summary/Keyword: C.E.C

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Appropriateness of MSDS by Means of the Measurement of Combustible Properties of Anisole (아니솔의 연소특성치의 측정에 의한 MSDS의 적정성)

  • Ha, Dong-Myeong
    • Fire Science and Engineering
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    • v.29 no.2
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    • pp.20-24
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    • 2015
  • For the safe handling of anisole, this study was investigated the explosion limits of anisole in the reference data. The flash points and auto-ignition temperatures (AITs) by ignition delay time were experimented. The lower flash points of Anisole by using closed-cup tester were experimented in $39^{\circ}C$ and $42^{\circ}C$. The lower flash points of Anisole by using open cup tester were experimented in $50^{\circ}C$ and $54^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for Anisole. The AIT of Anisole was experimented as $390^{\circ}C$. The lower explosion limit (LEL) by the measured the lower flash point for Anisole were calculated as 1.07 Vol%.

The Measurement of Combustible Properties of Cyclohexanol (사이클로헥산올의 연소특성치의 측정)

  • Ha, Dong-Myeong
    • Fire Science and Engineering
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    • v.28 no.2
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    • pp.64-68
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    • 2014
  • For the safe handling of cyclohexanol, this study was investigated the explosion limits of cyclohexanol in the reference data. The flash points and auto-ignition temperatures (AITs) by ignition delay time were experimented. The lower flash points of cyclohexanol by using closed-cup tester were experimented in$60^{\circ}C{\sim}64^{\circ}C$. The lower flash points of cyclohexanol by using open cup tester were experimented in $66^{\circ}C{\sim}68^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for cyclohexanol. The AIT of cyclohexanol was experimented as $297^{\circ}C$. The lower explosion limit (LEL) and the upper explosion limit UEL) by the measured the lower flash point and the upper flash point of cyclohexanol were calculated as 0.95 Vol% and 10.7 Vol%, respectively.

Measurement and Prediction of Combustion Properties of Styrene (스티렌의 연소특성치 측정 및 예측)

  • Ha, Dong-Myeong;Na, Byeong-Gyun
    • Journal of the Korean Institute of Gas
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    • v.17 no.4
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    • pp.70-76
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    • 2013
  • For the safe handling of styrene, this study was investigated the explosion limits of styrene in the reference data. The flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. As a results, the lower and upper explosion limits of styrene recommended 0.9 Vol.% and 8.0 Vol.%, respectively. The lower flash points of styrene by using closed-cup tester were experimented $29^{\circ}C{\sim}31^{\circ}C$. The lower flash points of styrene by using open cup tester were experimented $32^{\circ}C{\sim}36^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for styrene. The experimental AIT of styrene was $460^{\circ}C$.

Multiplication of Escherichia coli DH5α::gfp on Strawberry Fruit Surface (딸기과실 표면에서 Eschercia coli DH5α::gfp 증식)

  • Yun, Hyejeong;Park, Kyeonghun;Ryu, Kyoung Yul;Yun, Jong-Chul;Kim, Byung Seok
    • Food Science and Preservation
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    • v.20 no.2
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    • pp.250-256
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    • 2013
  • To verify the multiplication of microorganisms on the surface of strawberries, the fate of E. coli $DH5{\alpha}::gfp$ at different temperatures, times and strawberry extract concentrations were measured. The population of E. coli $DH5{\alpha}::gfp$ rapidly increased by 7.36~7.78 log CFU/g at $25{\sim}30^{\circ}C$ for 24 hr and slowly increased by 6.49~8.49 log CFU/g at $10{\sim}20^{\circ}C$ for 48 hr. However, E. coli $DH5{\alpha}::gfp$ did not grow at $10{\sim}15^{\circ}C$ on the surface of the strawberries, regardless of the contact times with the bacterial suspension. E. coli $DH5{\alpha}::gfp$ reached 1.52~3.26 log CFU/g at $20^{\circ}C$ as the contact frequency increased from two to six times. The contact frequencies did not significantly differ. In the case of the six-time contact on the surface of the strawberry at 25 and $30^{\circ}C$, the E. coli $DH5{\alpha}::gfp$ increased by 5.17 and 5.01 log CFU/g. The effects of the strawberry extracts on the growth of E. coli $DH5{\alpha}::gfp$ showed that sterilization and non-sterilization do not affect the growth of microorganisms for 96 hr. In the minimal broth, the growth of E. coli $DH5{\alpha}::gfp$ increased by 1 log CFU/g for 96 hr. In less than 50 percent of the strawberry extracts, the growth rate of E. coli $DH5{\alpha}::gfp$ was higher than in the control and increased by 4 and 5 log CFU/g at 50 and 25 percent of strawberry extracts, respectively. Therefore, E. coli $DH5{\alpha}::gfp$ can multiply and survive on the surface of strawberries when it comes into contact with the fruit extract.

Accuracy of the Position Fix and Local Fluctuation of Omega Signals in the South Coast of Korea (한국남해안에 있어서의 오메가신호의 지역적인 변화와 측위의 정도)

  • 안장영
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.17 no.2
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    • pp.59-63
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    • 1981
  • For the purpose of surveying accuracy of the position fix and local fluctuation of Omega signals in south coast of Korea, the author observe continuously the phase difference of the A-C pair and A-E pair form December 1, 1980, to February 28, 1981, at Cheju(33$^{\circ}$31'.0N, 126$^{\circ}$31.9E) and Busan(35$^{\circ}$7'.9 N, 129$^{\circ}$6'. 3 E). The analyzed results are as follows: 1. Omega signals at Cheju and Busan are positive correlation. Mean value of coefficients during all measured time is 0.70 with A-C pair and 0.75 with A-E pair. 2. Range of mean value of difference between the measured PPC at Cheju and Busan is 17.7~21.3 cels with A-C pair and -2.9~2.0 cels with A-E pair. 3. In case of using the differential Omega at Cheju and Busan, mean value of total errors of the position fix is 1.52 miles and its standard deviation is 0.21 miles.

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SiC/SiO2 Interface Characteristics in N-based 4H-SiC MOS Capacitor Fabricated with PECVD and NO Annealing Processes (PECVD와 NO 어닐링 공정을 이용하여 제작한 N-based 4H-SiC MOS Capacitor의 SiC/SiO2 계면 특성)

  • Song, Gwan-Hoon;Kim, Kwang-Soo
    • Journal of IKEEE
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    • v.18 no.4
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    • pp.447-455
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    • 2014
  • In this research, n-based 4H-MOS Capacitor was fabricated with PECVD (plasma enhanced chemical vapor deposition) process for improving SiC/$SiO_2$ interface properties known as main problem of 4H-SiC MOSFET. To overcome the problems of dry oxidation process such as lower growth rate, high interface trap density and low critical electric field of $SiO_2$, PECVD and NO annealing processes are used to MOS Capacitor fabrication. After fabrication, MOS Capacitor's interface properties were measured and evaluated by hi-lo C-V measure, I-V measure and SIMS. As a result of comparing the interface properties with the dry oxidation case, improved interface and oxide properties such as 20% reduced flatband voltage shift, 25% reduced effective oxide charge density, increased oxide breakdown field of 8MV/cm and best effective barrier height of 1.57eV, 69.05% reduced interface trap density in the range of 0.375~0.495eV under the conduction band are observed.

Effects of Fermentation Temperature on the Sensory, Physicochemical and Microbiological Properties of Kakdugi (깍두기의 발효숙성 온도가 관능적, 이화학적 및 미생물학적 특성에 미치는 영향)

  • 김성단;장명숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.5
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    • pp.800-806
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    • 1997
  • Effect of temperature on Kakdugi during fermentation was investigated by measuring sensory, physicochemical and microbiological, properties up to 57 days. The diced(2.5$\times$2.5$\times$2.5cm) Chinese radishes(Ra-phanus sativus L.) with other ingredients were fermented under the different temperatures. Kakdugi were stored at 4$^{\circ}C$ after keeping at 2$0^{\circ}C$ for 12 hours(treatment E) from initial fermentation to the end at each temperature on preparation. The pH was decreased to the range of 4.14~4.29 in the initial of pH 5.8, and total acidity was increased 2~4 times more than that of in the initial period (0.24%). And the changes of treatment A, B, and C were nearly constant up to 57 days in the range of 0.80~0.88% (pH 4.1). The changes of vitamin C showed sigmoidal curve, increasing significantly in the palatable period after decreasing gradually in the initial period. The content of vitamin C in treatment E was rapidly decreased, but that of treatment C was kept high content up to 57days. the number of lactic acid bacteria was remarkably increased in palatable period and was gradually decreased thereafter. The scores of aroma, taste, overall acceptability in sensory evaluation during the fermentation was high in order of treatment E, C, D, B and A. The scores of sensory evaluation treatment D and E during fermentation was rapidly decreased, however, treatment A, B and C were maintained. Changes of lactic acid bacteria, and sensory properties, among treatment A, B and C which kept a good quality up to 57 days, had high scores of sensory evaluation, abundant vitamin C in the palatable period. The result showed that Kakdugi fermented at 4$^{\circ}C$ after keeping at 2$0^{\circ}C$ for 36 hours had better taste and quality than those of other treatments.

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A Study on the Phase Transition of Heat-Treated CdS Thin Films (열처리한 CdS 박막의 구조변환에 관한 연구)

  • Kim, Geun-Muk;Han, Eun-Ju
    • Korean Journal of Materials Research
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    • v.9 no.8
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    • pp.782-786
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    • 1999
  • CdS thin films prepared by vaccum evaperation have been studied the characteristcs of room temperature of scanning electron microscoe(SEM), X-ray diffraction(XRD), energy dispersive X-ray(EDX), and photoluminescence(PL)spectra. The cubic to hexagonal structure phase transitin has been determined to be $350^{\circ}C~450^{\circ}C$. The results of compensated donor levels of $O_2$and Si impurites at S-vacancy were identified CdO and $Cd_2SiO_4$defects. The edge emission peaks measured by PL of room temperature was donor level accoding the theses $O_2$and Si impurites were due to 2.43eV($350^{\circ}C$) and 2.42eV(55$0^{\circ}C$) peak energies respectively. The structure transition annealing temperature was measured $370^{\circ}C$ similar to Ariza-Calderons result, $374^{\circ}C$ by CBD films.

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A study on the formation and properties of TMDSO/$O_2$ thin film by the RF Plasma CVD (RF Plasma CVD에 의한 TMDSO/$O_2$의 합성과 박막의 특성에 관한 연구)

  • Kim, I.S.;Kim, G.Y.;Kang, D.P.;Yun, M.S.;Park, S.H.
    • Proceedings of the KIEE Conference
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    • 1991.11a
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    • pp.265-268
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    • 1991
  • In the study, PPTMDSO(plasma-polymerized tetramethyldisiloxane) films were deposited on on glass substrate in a paralled plate reactor. As the function of RF power increased from 20 W to 110 W, and the substrate temperature increased from $25^{\circ}C$ to $100^{\circ}C$, the deposit ion rate, increased. When oxygen was intentionally added in monomer vapor, the concentration of Si-O-Si bonds increased while C-H, Si-H, -CH3, Si(CH3)x, -CH3, and Si-C bonds decreased in IR spectra. Thermal stability of PPTMSDO film were investigated and weight loss at $800^{\circ}C$ was 7.3 %.

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BOUNDARY-VALUED CONDITIONAL YEH-WIENER INTEGRALS AND A KAC-FEYNMAN WIENER INTEGRAL EQUATION

  • Park, Chull;David Skoug
    • Journal of the Korean Mathematical Society
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    • v.33 no.4
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    • pp.763-775
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    • 1996
  • For $Q = [0,S] \times [0,T]$ let C(Q) denote Yeh-Wiener space, i.e., the space of all real-valued continuous functions x(s,t) on Q such that x(0,t) = x(s,0) = 0 for every (s,t) in Q. Yeh [10] defined a Gaussian measure $m_y$ on C(Q) (later modified in [13]) such that as a stochastic process ${x(s,t), (s,t) \epsilon Q}$ has mean $E[x(s,t)] = \smallint_{C(Q)} x(s,t)m_y(dx) = 0$ and covariance $E[x(s,t)x(u,\upsilon)] = min{s,u} min{t,\upsilon}$. Let $C_\omega \equiv C[0,T]$ denote the standard Wiener space on [0,T] with Wiener measure $m_\omega$. Yeh [12] introduced the concept of the conditional Wiener integral of F given X, E(F$\mid$X), and for case X(x) = x(T) obtained some very useful results including a Kac-Feynman integral equation.

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