• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.85-93
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• 1988

Solvolyses of t-butylhalides (X = Cl, Br, I) in quasi isodielectric solvent system, MeOH-nitromethane, MeOH-nitrobenzene and MeOH-ethyleneglycol have been studied kinetically. Methanolyses for t-butylhalides in MeOH-NM and MeOH-NB show rate maxima at 40~100 % (v/v) MeOH. The rate maxima observed have been interpreted as a result of cooperative enhancement of polarity-polarizability and hydrogen bonddonor ability of solvents. The influences of polarity-polarizability and hydrogen bonddonor ability on reactivities of substrates have been discussed in terms of Y value changes. The solvolysis rates for t-butylhalides in E.G. are more than 20 fold faster than those in MeOH and this was attributed to the solvent structure of E.G.

• Communications of Mathematical Education
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• v.22 no.3
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• pp.337-347
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• 2008

'Slope' is an invariant of a straight line and 'Linear Equation' is an algebraic representation of a straight line in the cartesian plane. The concept 'slope' is necessary for algebraically representing a geometrical figure, line. In this article, we investigate how those concepts are dealt with in school mathematics and suggest some improvement methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.447-450
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• 2014

In this paper efficient design of wireless tablet system using GalaxyNote device for PC was proposed. The designed portable tablet consists of GalaxyNote device, Stylus Pen, and Bluetooth-to-serial converter. To transmit coordinate information of Stylus Pen on GalaxyNote device to PC, wireless portable tablet uses bluetooth wireless communications. After the custom mouse filter driver divides received coordinate into x-coordinate and y-coordinate, it controls position of mouse pointer using the converted coordinates while Windows application programs are running.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.1-8
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• 2009

EMMC(Entrapped Mixed Microbial Cell) process which is a kind of active cell immobilizing method was applied to treat fisheries processing wastewater biologically. Kinetic constants were calculated for organic and nitrogen removal and effect of effluent recycling on system performance was evaluated also. Yield coefficient, Y showed relatively low value compared with Y value obtained from conventional activated sludge process. It means that EMMC process can reduce amount of excess sludge significantly compared with conventional activated sludge process. Endogenous respiration coefficient $k_e$ of EMMC process also showed relatively low value compared with that of conventional activated sludge process. Yield coefficient Y, endogenous respiration coefficient $k_e$ and half saturation constant $k_s$ obtained from EMMC process in terms of nitrification were compared with reported value from literature based on suspended growth nitrification system. The value of Y obtained from this study has no difference compared with values obtained from literature review and $k_e$ of this study was low but $k_s$ of this study was high compared than values obtained from suspended growth nitrification system. To evaluate the effect of internal recycling on system performance, system was operated with internal recycling ratio of 1.5Q, 2.0Q, 2.5Q and 3.0Q. increase of internal recycling ratio effect more greatly on improvement of denitrification efficiency than that of nitrification efficiency. Accordingly, optimization of internal recycling ratio has to be based on improvement of anoxic reactor performance.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.337-345
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• 1973

The nonstoichiometry of the iron oxide system has been studied by analyzing the weight loss of a sample, measured by using a quartz microbalance, in a temperature range from $0^{\circ}C$ to $1200^{\circ}C$ under oxygen pressures from $10^{2}mmHg$ to $10^{-4}mmHg$. The Y values of the formula, $FeO_{1+\gamma}$, that have been obtained by this means for various conditions of temperature and pressure in this range are considered to be more accurate than values obtained by methods requiring thste quenching of the sample before measurements are made. The plots of log Y vs $log PO_2$ (or $log Y =_n log PO_2$) show linearity and n calculated from the slope of the plot is about 1/10 at $1000^{\circ}C$, indicating a difference between the nonstoichiometric and oxidation mechanisms. The condition for the formation of stoichiometric FeO was determined to be $1200^{\circ}C$ under $10^{-3}mmHg$ of $O_2$ and the composition of the oxide under standard conditions was $FeO_{1.11185}$. As in general more oxygen dissolves into the oxide system at lower temperatures and higher oxygen pressures, the deviation from stoichiometric FeO is greater under those conditions. A comparison of the change in conductivity of the sample indicates that full phase transition does not take place with conductivity transition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.463-466
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• 2010

In this paper, CCTV based fire surveillance system should aim to development. Advantages and Disadvantages analyzed of Existing sensor-based fire surveillance system and video-based fire surveillance system. To national support U-City, U-Home, U-Campus, etc, spread the ubiquitous environment appropriate to fire surveillance system model and a fire judgement technology. For this study, Microsoft LifeCam VX-1000 using through the capturing images and analyzed for apple and tomato, Finally we used H.264. The client uses the Linux OS with ARM9 S3C2440 board was manufactured, the client's role is passed to the server to processed capturing image. Client and the server is basically a 1:1 video communications. So to multiple receive to video multicast support will be a specification. Is fire surveillance system designed for multiple video communication. Video data from the RGB format to YUV format and transfer and fire detection for Y value. Y value is know movement data. The red color of the fire is determined to detect and calculate the value of Y at the fire continues to detect the movement of flame.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.117-117
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• 2010

최근 10여년간 OLED는 급속한 기술발전으로 효율의 급속히 향상되어 100 lm 이상의 소자가 발표되고 있어, 디스플레이와 조명용 광원으로서의 응용 가능성이 증가하고 있다. 또한 에너지 및 환경의 중요성이 대두되며 효율은 점차 중요해 지고 있다. OLED의 효율 향상을 위해, 내부 양자효율이 25%인 형광 OLED를 대체할 수 있는, 인광 OLED가 대두되고 있다. 인광 OLED는 내부양자 효율이 형광 OLED에 비해 4배. 즉 100%의 내부양자 효율을 갖는다. 그러나 주로 사용되는 청색인광 물질인 FIrpic, Fir6 등의 수명이 짧다는 점과 색 좌표의 y값이 0.20 이상으로 하늘색 계열의 색특성을 보이는 등 여러 단점이 있다. 현제 이러한 단점을 보완하고자 하는 여러 연구가 진행되고 있다. 이에 본 연구에서는 다양한 호스트 물질을 사용, 도펀트 물질인 FIrpic을 도핑하여 청색인광의 효율을 높이고 수명을 증진시키고자 한다. 양극전극으로 RF 플라즈마 처리한 ITO를 사용하였으며, 진공증착방법을 사용하여 정공 주입층(HIL)으로 2-TNATA와 정공 수송층(HTL)으로 a-NPD을 증착하였으며, 전자 수송층(ETL)으로 Balq, 전자주입층(EIL)으로 LiF와 음극전극으로 Al을 증착하였다. 발광층(EML)에 사용되는 호스트 물질은 mCP, TCTA, CBP 등으로 다양화 하여 도펀트 물질인 FIrpic을 각각의 호스트 물질에 8 wt%으로 도핑하여 OLED 소자를 제작하였고, 전기 및 광학적 특성을 평가하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.2
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• pp.54-60
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• 1984

In this paper, the modified Hunt's constrained least squares estimation method for image restoration is studied with the parameter ${\alpha}$ which represents the effect of inverse filter, And it is akown that high frequency components in the restored image obtained by the proposed method are emphasized by optimizing the constraining factor ${\gamma}$, depending upon ${\alpha}$.

• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.155-159
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• 1978

Phenol utilizing yeast No. 558 isolated from soil sewage sediment was able to use substantial amount of phenol as the sole carbon source, and the biomass productivity by this organism was very excellent. This organism could grow well in 1000 ppm of phenol concentration, the maxim-um specific growth rate obtainable at pH 5.0, 3$0^{\circ}C$ was 0.27/hr., and the biomass yield coefficient Y vs. consumed phenol was 3.2. Maximum production rate of biomass was observed at 35$^{\circ}C$, pH 3.5 to pH 4.5, and the addition of the 0.005~0. 01% yeast extract was the most effective. Addition of HgCl$_2$ and phenyl hydrazine, inhibitors of oxide-reductase, in the phenol containing cultural liquid caused this organism no-growth at the concentration of 10$^{-5}$ M, 10$^{-3}$ M respectively. This organism could utilize not only phenol but catechol, resorcinol and benzidine.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.9-14
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• 1988

Perovskite type compounds of the $La_{1-x}Ca_xFeO_{3-y}$ system were prepared from stoichiometric mixtures of La_2O_3,\;CaCO_3$, and Fe(NO-3)_3{\cdot}9H_2O$ by heating at 1100$^{\circ}C$ for 24 hours. The crystallographic structures of the solid solutions of all compositions were orthorhombic systems. X-ray diffraction and Mohr salt analysis revealed that at higher y value the phase transition due to vacancy ordering occured and that the lattice volume decreased when the x value was increased. The value of nonstoichiometric ratio y were found to be in the range of $0.0{\sim}0.5$. Electrical conductivities of this systems are measured in temperature range of -100 to 100$^{\circ}C$. Ionic contribution to total conductivity was found from activation energy in the phase containing the open pathway due to vacancy ordering.