• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.73-79
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• 1997

This research was intended as an investigation of applying Reduced Pressure Evaporation as efficient treatment method for landfill leachate. According to the variance of time, temperature, pressure and pH in experiments, the properties of leachate treatment are follows. The removal efficiencies of COD, NH$_{3}$-N, TOC, Conductivity and SS on the basis of reaction time was 96.4%-97.5%, -1.4%-53.7%, 81.7%-89.0%, 92.0%-95.3% and 99.86%-99.97%, respectively. When the pH of Influent was 7.5, the pH of effluent was increased to 10-11 with time elapse. It is concluded that the orgin of pH increase may be ammonia. When the properties of concentrate were investigated at the concentration ratio 90%(V/V), concentration difficiency represented in the ratio of experimental value/calculated value had following orders ; COD>TOC>NH$_{3}$-N>Conductivity>SS. Concentrate had good precipitation because of additive thermal treatment in the process. When evaporation experiments with pH adjustment of 4.0, 6.0, 7.5, 9.0 and 10.0 were performed ; Acidic evaporation experiments(pH 4.0, 6.0) showed low removal efficiency(81.6, 87.6%) of COD and high removal efficiency (97.5%. 84.6%) of NH$_{3}$-N at initial evaporation. Basic evaporation(pH 9.0, 10.0) showed high removal efficiency (97.2%, 98.9%) of COD and very low removal efficiency (-7.4%, -27.2%) of NH$_{3}$-N at initial evaporation.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.457-459
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• 2015

Observations show that the accretion flows in low-luminosity active galactic nuclei (LLAGNs) probably have a two-component structure with an inner hot, optically thin, advection dominated accretion flow (ADAF) and an outer truncated cool, optically thick accretion disk. As shown by Taam et al. (2012), within the framework of the disk evaporation model, the truncation radius as a function of mass accretion rate is strongly affected by including the magnetic field. We define the parameter ${\beta}$ as $p_m=B^2/8{\pi}=(1-{\beta})p_{tot}$, (where $p_{tot}=p_{gas}+p_m$, $p_{gas}$ is gas pressure and $p_m$ is magnetic pressure) to describe the strength of the magnetic field in accretion flows. It is found that an increase of the magnetic field (decreasing the value of ${\beta}$) results in a smaller truncation radius for the accretion disk. We calculate the emergent spectrum of an inner ADAF + an outer truncated accretion disk around a supermassive black hole by considering the effects of the magnetic field on the truncation radius of the accretion disk. By comparing with observations, we found that a weaker magnetic field (corresponding to a bigger value of ${\beta}$) is required to match the observed correlation between $L_{2-10keV}/L_{Edd}$ and the bolometric correction $k_{2-10keV}$, which is consistent with the physics of the accretion flow with a low mass accretion rate around a black hole.

• Korean Journal of Human Ecology
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• v.1 no.2
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• pp.89-99
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• 1998

This study was carried out to investigate some antioxidative effects of stewed pumpkin juice (SPJ) and the SPJs added with ginger (SPJ-G), onion (SPJ-O), jujube (SPJ-J) or boxthorn (SPJ-B), respectively, on the lipid oxidation of soybean oil (S) and mackerel pike boiled ground (MPBG). Antioxidative substances of SPJ were extracted by using the two solvent layers of n-hexane:acetone (1:1)(H) and methanol:water (7:3)M. The antioxidative effects of the extracts were observed by the peroxide value (P.O.V.) and thiobabituric acid (T.B.A.) value. The P.O.V. and T.B.A. value of two solvent extracts of S and MPBG showed significantly lower than those of S and MPBG. The SPJ showed very distingnished antioxidative effects. It was considered that melanoidine extracted by using methanol:water (7:3) solvent as well as carotenoid extracted by using n-hexane:acetone (1:1) solvent had an antioxidative effect. During storage, T.B.A. value of MPBG significantly increased, while that of MPBG-SPJ significantly decreased more than that of MPBG. T.B.A. value of MPBG-SPJs decreased much than that of MPBG-SPJ, SPJ-O, SPJ-G, SPJ-J and SPJ-B, in order of abundance, showed higher level of antioxidative effects than SPJ. (Korean J Human Ecology 1(2):89∼99, 1998)

• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1517-1533
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• 2015

In this paper, we prove the existence of at least three nontrivial solutions to nonlinear discrete boundary value problems $$\{^{-{\Delta}_{p,{\omega}}u(x)+V(x){\mid}u(x){\mid}^{q-2}u(x)=f(x,u(x)),x{\in}S,}_{u(x)=0,\;x{\in}{\partial}S}$$, involving the discrete p-Laplacian on simple, nite and connected graphs $\bar{S}(S{\cup}{\partial}S,E)$ with weight ${\omega}$, where 1 < q < p < ${\infty}$. The approach is based on a suitable combine of variational and truncations methods.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.1
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• pp.1-5
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• 2008

The output voltage value of AC high voltage source has been usually obtained by multiplying low voltage value measured at both terminals of low voltage resistor by the dividing ratio of the high voltage capacitive divider. From the dividing ratio determined of each 200 kV capacitive divider, we have developed step-up method for measuring the output voltage up to 400 kV using two same type of 200 kV capacitive dividers connected in series. The theoretical dividing ratio of 400 kV capacitive dividers connected in series coincides with that of manufacturer's certification within measurement uncertainty. Thus, this developed step-up method makes it possible to extend the range of output voltage from 200 kV to 400 kV. Furthermore, The dividing ratio of divider under test obtained using this step-up method is consistent with that obtained using one 200 kV high voltage divider within corresponding uncertainties.

• Korean Journal of Materials Research
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• v.19 no.9
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• pp.510-515
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• 2009

The compound of 2,6-Bis[(9-phenylcarbazolyl)ethenyl]naphthalene (BPCEN-1), 2-[6-{1-Cyano-2-(9-phenylcarbazoly)vinyl}naphthyl]-3-(9-phenylcarbazolyl)acrylonitrile (BPCEN-2), 2,6-Bis[{4-(1-naphthy l)phenylamino} styrenyl] naphthalene (BNPASN-1), 2-[6-{1-Cyano-2-(naphthylphenylaminophenyl) vinyl}naphthyl]-3-(naphthylphenylaminophenyl)acrylonitrile (BNPASN-2) was analyzed electrochemically and spectroscopically and can be obtained by bonding phenylcarbazolyl, naphthylphenylaminophenyl and -CN ligands to 2,7-naphthalene. The electrochemical and spectroscopic study resulted in the P-type (BPCEN-1, BNPASN-1) being changed to N-type (BPCEN-2, BNPASN-2) according to -CN bonding despite having the same structure. The value of band gap(Eg) was revealed to be small as HOMO had shifted higher and LUMO lower. The Eg value for naphthylphenylaminophenyl ligand was reduced because it has a smaller HOMO/LUMO value than that of phenylcarbazolyl from a structural perspective. The electrochemical HOMO/LUMO values for BPCEN-1, BPCEN-2, BNPASN-1, BNPASN-2 were measured to be 5.55eV / 2.83eV, 5.73eV / 3.06eV, 5.48eV / 2.78eV, and 5.53eV / 2.98eV, respectively. By -CN ligand, the UV max, Eg and PL max were shifted to longer wavelength in their spectra and the luminescence band could be also confirmed to be broad in the photoluminescence (PL) spectrum.

• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.25-28
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• 2016

We investigate the effect of interface states on the endurance of a charge trap flash (CTF) NOR array using charge pumping methods. The endurance test was completed from one cell selected randomly from 128 bit cells, where the memory window value after 10² program/erase (P/E) cycles decreased slightly from 2.2 V to 1.7 V. However, the memory window closure abruptly accelerated after 10³ P/E cycles or more (i.e. 0.97 V or 0.7 V) due to a degraded programming speed. On the other hand, the interface trap density (Nit) gradually increased from 3.13×10¹¹ cm⁻² for the initial state to 4×10¹² cm⁻² for 10² P/E cycles. Over 10³ P/E cycles, the Nit increased dramatically from 5.51×10¹² cm⁻² for 10³ P/E cycles to 5.79×10¹² cm⁻² for 10⁴ P/E cycles due to tunnel oxide damages. These results show good correlation between the interface traps and endurance degradation of CTF devices in actual flash cell arrays.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1981-1985
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• 2005

Kinetic studies have been performed for alkaline hydrolysis of a series of [(methoxy)(p-substituted styryl)carbene]pentacarbonyl chromium(0) complexes ($(CO)_5$Cr=$C(OCH_3)CH=CHC_6H_4X$, X = p-$OCH_3$, p-$CH_3$, H, p-Cl, p-$NO_2$). Second-order rate constants $(k_{{OH}^-})$ for the alkaline hydrolysis in 50% acetonitrile-water(v/v) were determined spectrophotometrically at various temperatures. At a low pH region (pH < 7.5), the observed rate constant $(k_{obs})$ remained constant with a small value, while in a high pH region (pH > 9.5), $k_{obs}$ increases linearly with increasing the pH of the medium. The second-order rate constants $(k_{{OH}^-})$ increase as the substituent X changes from a strong electron donating group to a strong electron withdrawing group. The Hammett plot obtained for the alkaline hydrolysis is consisted of two intersecting straight lines. The nonlinear Hammett plot might be interpreted as a change in the rate-determining step. However, the fact that the corresponding Yukawa-Tsuno plot is linear with $\rho$ and r values of 0.71 and 1.14, respectively indicates that the nonlinear Hammett plot is not due to a change in the rate-determing step but is due to ground-state stabilization through resonance interaction. The positive $\rho$ value suggests that nucleophilic attack by $OH^-$ to form a tetrahedral addition intermediate is the rate-determining step. The large negative ${\Delta}S^\neq$ value determined in the present system is consistent with the proposed mechanism.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.184-191
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• 1986

Membrane potential of cells in the isolated rabbit coronary sinus was measured by conventional glass microelectrode and investigated the effect of $[K^+]_0$ variation in control, 20 mM and Ach-containing Tyrode solution. The results obtained were as follows: 1) The resting membrane potential exposed to normal Tyrode solution containing 3 mM $K^+\;was\;about\;-60{\sim}\;-65mV$. At extracellular $K^+$ concentrations from 1 to 30 mM the resting Potential was reasonably well described by Goldman -Hodgkin -Katz equation on the assumption that $[K^+]_1$ was 150 mM and that the ratio of membrane permeability coefficient for $Na^+\;and\;K^+,\;P_{Na}/P_K\;({\alpha})$ was 0.07. 2) In 20 mM Na-Tyrode solution (replacing by equimolar Tris) the resting membrane potential was hyperpolarized by 15 to 20 mV and showed slightly deviated to depolarized direction compared to the predicted value by Goldman-Hodgkin -Katz equation. 3) In the presence of $10^{-6}M$ Ach, the resting potentials at $[K^+]_0$ levels from 1 to 30 mM were well fitted with the predicted value on the assumption that $P_{Na}/P_K$ was 0.0144. It could be concluded that the low resting membrane potential of coronary sinus cells reflects a relatively high ratio $P_{Na}/P_K$ of about 0.07.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.249-254
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• 1993

The dried cinnamon was extracted with water and 70% ethanol and studied for the several extraction conditions of temperature, time, solvent addition ratio and number of extraction on mineral components and physical properties of the extracts. Mineral components significantly increased as the extraction temperature increased. More than 8 hours of extraction showed a little improving while solvent ratio (V/W) up to 60 times (V/W) significantly increased the mineral components, particularly Cu, Zn, Fe, Na in water extracts and Fe, Mn, K in 70% ethanol extracts. Absorbance at 285 mm decreased as the temperature raised up to the range of $60{\sim}80^{\circ}C$. The Hunter a-value was much affected with extraction conditions and L-value and transmittance were changed similarily while pH was little changed.