• 대한화장품학회지
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• 제15권1호
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• pp.51-62
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• 1989

Inclusion complex formation of octyldimethl p-aminobenzoate with $\beta$-cyclodextrin in aqueous solution and in the solid state was studied by the solubility method, spectroscopic(UV, FT-lR) and X -ray diffractometry. The solid complex of octyldimethy p-aminobenzoate with $\beta$-cyclodextrin was obtained in molar ratio of 1 : 2(guest/host). A spatial relationship between host and guest molecule was clearly reflected in the magnitude of the apparent stability constant (K') and in the stoichiometry of the inclusion complex. Furthermore, a typical type Bs phase-solubility diagram was obtained for octyldimethyl p-aminobenzoate and p -cyclodextrin in water at $25^{\circ}C$. The results indicated that the solubility of the guest molecule was higher by the formation of $\beta$-cyclodextrin inclusion complex.

• 대한화학회지
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• 제56권2호
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• pp.212-216
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• 2012

The kinetics of oxidation of nicotinic acid by peroxomonosulfate (PMS) has been studied in acetate buffers. Stoichiometry of the reaction corresponds to the reaction of one mole of the oxidant with a mole of nicotinic acid. N${\rightarrow}$O product has been confirmed both by UV visible and IR spectroscopy. The reaction is second order viz. first order with respect to each reactant. Activation parameters have also been evaluated. A plausible reaction mechanism is mentioned and the derived kinetic rate law accounts for experimental observations.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.63-66
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• 2004

Transparent MgO thin films were deposited on glass substrates by electron beam evaporation of MgO (99.99%) under $O_2$ atmosphere at 150-250 $^{\circ}C$. These films were characterized for their useful properties such as thickness, transmission, and refractive index using ultraviolet / visible (UV/VIS) spectrophotometer, scanning electron microscopy (SEM), and Spectroscopic Ellipsometry. The thickness of MgO films were measured by alpha step instrument and found to be 600 nm to 1000 nm and are meeting the stoichiometry. The transmission spectrum of these films shows transmittance values ${\sim}$92%..

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.125-128
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• 2000

ZnO thin films on silicon substrates have been deposited by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the effect of oxygen post-annealing treatment on the property of ZnO thin films, deposited film has been annealed at the substrate temperature of $440^{\circ}C$. After post-annealing treatment in the oxygen ambient, the stoichiometry of ZnO film has been characterized be improved which results in higher UV emission intensity of photoluminescence.

• 한국전기전자재료학회논문지
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• 제14권6호
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• pp.481-486
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• 2001

ZnO thin films on glass substrate were depostied by RF magnetron reactive sputter with various argon/oxygen gas ratios and substrate temperatures. Crystallinities, surface morphologies, chemical compositions, and electrical properties of the films were investigated by XRD, SEM, XPS and electrometer(keithley 617). All films showed a strong preferred orientation along the c-axis on glass substrate, and the chemical stoichiometry was obtained at Ar/O$_2$.=50/50. The propagation velocity of ZnO SAW filter was about 2,590 m/sec and insertion loss was a minimum value of abut -21dB.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.1-9
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• 1999

Liquid Petroleum Gas (LPG) has been widely used for commercial light-duty vehicles worldwide. Since LPG has a higher octane number and a lower maximum combustion temperature than gasoline , it becomes more popular fuel for reducing exhaust emissions. In tihs study, mathematical models of air intake and fuel delivery system are presented, and a PI-controller is designed for air-fuel ratio control. Hardware and software of an engine control module (ECM) are designed for an LPG engine. The ECM is built using a Motorola MC68HC05. In order to control the air-fuel ratio at stoichiometry, the PI-control algorithm is implemented in the ECM. The experiment results show the proto LPG ECM and its control scheme perform well to meet the stoichiometric air-duel ratio requirement.

• 약학회지
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• 제36권6호
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• pp.577-581
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• 1992

Norfloxacin complexes of $Fe^{2+}$, $Cu^{2+}$ and $Al^{3+}$ have been prepared as solids. The stoichiometry of the complexes has been established. IR investigation indicates the metal-ligating sites in norfloxacin. The bioactivities of complexes all lower than that of norfloxacin. The solubilities and partition coefficients have been measured as a function of temperature. The data are used to evaluate the thermodynamic parameters ${\Delta}G$, ${\Delta}H$, ${\Delta}S$ for the solute transfer process and compared with the parent quinolone, norfloxacin. The existence of such complexes is discussed in the light of quinolone mode-of-action theories.

• 한국결정성장학회지
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• 제24권5호
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• pp.219-223
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• 2014

Pulsed laser ablation in liquid medium was successfully employed to synthesize hydroxyapatite colloidal nanoparticles. The crystalline phase, particle morphology, size distribution and microstructure of the hydroxyapatite nanoparticles were investigated in detail. The obtained hydroxyapatite nanoparticles had spherical shape with sizes ranging from 5 to 20 nm. The laser ablation and the nanoparticle forming process were discussed with explosive ejection mechanism by investigating change of surface morphology on target. The analytical results of XPS, FT-IR and Raman spectroscopy confirms that the stoichiometry and bonding properties of the hydroxyapatite nanoparticles are in good agreement with reported bulk hydroxyapatite materials.

• The Korean Journal of Ceramics
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• 제1권1호
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• pp.45-54
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• 1995

Four kinds of silicon nitride based ceramic materials have been hot pressed. Effect of the sintering additives on the phase transformation, microstructural development and mechanical properties was investigated. While sintering under the same condition a big difference among the microstructures of the specimens, they appeared alike if sintered to have a similiar $\alpha$-$\beta$ phase ratio. The specimen of the stoichiometric $\alpha$-$\beta$ sialon composition showed very limited amount of the intergranular glassy phase and a significant degree of the residual stress. It exhibited almost no strength degradation up to $1300^{\circ}C$, and the strength of the specimen degraded more as its composition deviated from the stoichiometry.

• 한국세라믹학회지
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• 제42권9호
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• pp.613-617
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• 2005

We present the results of a combined magnetization, dc and magneto-transport study of the n = 2 Ruddlesden-Popper compound $Ca_3Mn_2O_7$ The negative thermoelectric powder is observed. The magnetic measurement data show that there is sharp magnetic transition at 134 K. However, the de and magnetoresistance of $Ca_3Mn_2O_7$ show no particular transport. Transport properties of the compound $Ca_3Mn_2O_7$ are interpreted in terms of activated hopping of small polarons in non-adiabatic regime. Polarons are most probably formed around $Mn^{3+}$ sites created by oxygen sub-stoichiometry.