• Journal of information and communication convergence engineering
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• v.8 no.2
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• pp.234-237
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• 2010

P300 component of the event-related potential(ERP) has been studied for theoretical, empirical, and clinical applications. Nowadays the 1-, 2-, and 3-stimulus oddball paradigms are used for eliciting P300 component of EEG in the auditory stimulus experiments. In this paper, we used a method to add one more stimulus to the 3-stimulus auditory paradigm. The adding stimulus has not the same volume but the same tone of the target stimulus. The 4-stimulus oddball paradigm to use two targets is used to elicit the P300 event-related potentials. In 4-stimulus oddball paradigm, an infrequent non-target (p=0.10) is presented in addition to two infrequent targets (p=0.10) and a frequent standard (p=0.70). Two target stimuli elicited a P300 component with a parietal maximum distribution. The amplitude of the P300 in target 2 was larger than that in target 1 and the latency of the P300 in target 2 was longer than that in target 1. The P300 component due to target 2 stimuli was larger than that due to target 1 stimuli. The experimental results approve that the 4-stimulus oddball paradigm can elicit P300 component clearly. The results are compared with the results of the traditional oddball paradigm.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.62-67
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• 2019

This study was focused on the design and the performance analysis of integral Hot BoP for recovering waste heat from high-temperature exhaust gas in 2 kW class solid oxide fuel cell (SOFC). The hot BoP system was consisted of a catalytic combustor, air preheater and steam generator for burning the stack exhaust gas and for recovering waste heat. In the design of the system, the maximum possible heat transfer was calculated to analyze the heat distribution processes. The detail design of the air preheater and steam generator was carried out by solving the heat transfer equation. The hot BoP was fabricated as a single unit to reduce the heat loss. The simulated stack exhaust gas which considered SOFC operation was used to the performance test. In the hot BoP performance test, the heat transfer rate and system efficiency were measured under various heat loads. The combustibility with the equivalent ratio was analyzed by measuring CO emission of the exhaust gas. As a result, the thermal efficiency of the hot BoP was about 60% based on the standard heat load of 2 kW SOFC. CO emission of the exhaust gas rapidly decreased at an equivalent ratio of 0.25 or more.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.5
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• pp.451-461
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• 2005

The effect of carbon dioxide on yeast growth was investigated during the cultivation of pH 5.0 and pH 6.8. by replacing the nitrogen part with carbon dioxide under aerobic conditions. The values of the specific growth rate under pH 5.0 and pH 6.8 conditions became 64.0% and 46.9%, respectively, compared to those before the change in gas composition. This suggests that the effect of carton dioxide was greater pronounced in pH 6.8 than in pH 5.0. The genome-wide transcriptional response to elevated carbon dioxide was examined using a DNA microarray. As for upregulated genes, it was noteworthy that 3 genes were induced upon entry into a stationary phase and 6 genes were involved in stress response. Of 53 downregulated genes, 22 genes were involved in the ribosomal biogenesis and assembly and 5 genes were involved in the lipid metabolism. These facts suggest that carbon dioxide could bring the cell conditions partially to a stationary phase. The ALD6 gene encoding for cytosolic acetaldehyde dehydrogenase was downregulated, which would lead to a lack of cell components for the growth. The downregulation of ALD6 was greater in pH 6.8 than in pH 5.0. consistent with physiological response. This suggests that it might be the most effective factor for growth inhibition.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.619-624
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• 2015

This study experimentally determined the effect of titanium tetrachloride (TiCl₄) concentration ([TiCl₄]) (0.25-0.55 mM) and initial pH (3-11) on phosphorus (P) removal in synthetic wastewater (2 mg P/L). The P removal efficiency increased when [TiCl₄] increased. The P removal efficiency showed a parabolic trend with an inflection point at pH 7. At the molar ratio of TiCl₄ and P>6.2, the P removal efficiency was over 90% and the residual P concentration was less than 0.2 mg/L. Within the design boundaries, the complete P removal could be achieved at 7.0≤initial pH≤8.5 and 0.43≤[TiCl₄]≤0.55 mM. The final pH was over 5.8 at initial pH≥7.7 and [TiCl₄]≥0.35 mM. The results showed that TiCl4 was effective in P removal in water so that it could be an alternative chemical for P removal.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.779-784
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• 2007

Dinitrophenol is preventing cells from making energy for growth and it has been suggested that pH may be important in mitigating effects of uncouplers. The effect of pH on toxicity of dinitrophenol at high concentration was investigated, over a pH range of 5.7 to 8.7. DNP inhibition was found to be strongly dependent on mixed liquor pH. The DNP degradation rate was highest in the pH range of 7.0 to 7.8; at pH 6.0 degradation of 0.41 mM dinitrophenol was significantly inhibited; at pH <5.7, dinitrophenol degradation was completely inhibited after approximately 25% of the dinitrophenol was degraded. However no significant effect of pH variation was seen on glucose uptake by the activated sludge mixed culture.

• Journal of the Korean Applied Science and Technology
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• v.10 no.2
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• pp.65-72
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• 1993

The kinetics of the addition of thiourea to cinnamenylisophorone derivatives(X : H, p-Br, $p-CH_3$ $m-CH_3$, $p-OCH_3$) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-$H_2O$ at $25^{\circ}C$. A rate equation which can be applied over wide pH range(pH $1.0{\sim}13.0$) was obtained. In order to investigate the substituent effects of cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of uncleophilic addition of thiourea to cinnamenylisophorone derivatives was facilitated by electron donating group. It was found that addition of neutral thiourea which was not dissociated at the pH $1.0{\sim}9.0$ was proceeded, the reaction was proceeded by addition of dissociated anion of thiourea above the pH 10.0. On the basis of this kinetic study, the reaction mechanism of nucleophilic addition of thiourea was investigated.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.46-49
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• 2005

Curdlan, a natural $\beta-1,3-glucan,$ has been studied as drug carrier due to its unique properties including its thermal gelling characters. In this study, curdlan was chemically acetylated for pH-sensitive drug delivery. Curdlan acetate microspheres(CAMs) were prepared by the solvent evaporation method. The size of the CAMs was below $200{\mu}m.$ The drug loading efficiency of microspheres was approximately $58.44\%$. In the swelling test, the CAMs showed pH-sensitive behavior. The swelling capacity of microspheres at pH 7.4 was much greater than at pH 1.4. Also, release rate of indomethacin(IND) at pH 7.4 from the CAMs was faster than that at pH 1.4. Therefore the CAMs have potential for the controlled release of IND over an extended period of time.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.897-900
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• 2008

Various sequences of pH change were applied in a batch bioreactor to investigate pH shock effects on geldanamycin production by Streptomyces hygroscopicus subsp. duamyceticus JCM4427. In the control culture where the pH was not controlled, the maximum geldanamycin concentration was 414 mg/l. With the pHS1 mode of pH shock, that is, an abrupt pH change from pH 6.5 to pH 5.0 and then being maintained at around pH 5.0 afterward, 768 mg/l of geldanamycin was produced. With pHS2, in which the pH was changed sequentially from pH 6.7 to pH 5.0 and then back to pH 6.0, 429 mg/l of geldanamycin was produced. With pHS3 having a sequential pH change from pH 6.0 to pH 4.0 and then back to pH 6.5 followed by the third pH shock to pH 5.5, no geldanamycin production was observed. Considering that the productivity with pHS1 was about two-fold of that of the control culture with no pH control, we concluded that a more sophisticated manipulation of pH would further promote geldanamycin production.

• Membrane and Water Treatment
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• v.14 no.1
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• pp.27-33
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• 2023

In previous studies, solely ferric (Fe³⁺) and calcium (Ca²⁺) ions were commonly used for removal of PO₄-P (considered as T-P in this study) in wastewater via chemical precipitation. Herein, the removal of total phosphorus (T-P) in wastewater was performed using various mineral and lime dissolved solutions. The dissolution kinetics of different minerals (feldspar, olivine, elvan, illite, sericite, and zeolite) and lime was compared and used their solutions for T-P removal of real wastewater. The highest T-P removal (almost 90%) was obtained by the lime dissolved solution and followed by zeolite, illite, feldspar, and others. We observed a significant co-relationship (R of 0.96) between the amount of initial Ca²⁺ and T-P removal. This was induced by formation of hydroxyapatite-like mineral via Ca-P precipitation reaction at high pH solution. Furthermore, additional removal of suspended solid (SS) and chemical oxygen demand (COD) was achieved by only lime dissolved solution. Finally, the lime-feldspar dissolved solutions were prepared at different ratios (10-50%), which showed a successive T-P removal up to two times by samples of 40 and 50%.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.112-116
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• 2005

We investigated the surface modification method for the preparation of organic-inorganic hybrid composite thin film. Gelatin obtained from the decomposition of collagen was allowed to adsorb in a polystyrene tissue culture dish for 2 h to from layers of gelatin. Supersaturated ionic solution of calcium and phosphorus was injected on the gelatin adsorbed layer to form calcium phosphate thin film. During the initial period of incubation, nucleates were formed. With increase of the incubation time, CaP (calcium phosphate) thin film grew on the surface of the culture dish. The gelatin/CaP thin film displayed the highly porous three-dimensional surface structure. Attenuated, total reflectance Fourier transform, infra-red spectroscopy (ATR-FTIR) was used to analyze the chemical properties of CaP film. The analysis demonstrated that the CaP film formed at initial period of treatment appeared to be amorphous. With increase of incubation time, the crystallinity of the film was slightly increased, but the presence of the peaks for the low crystalline CaP confirmed that the CaP thin film prepared in this study was poorly crystallized.