• Journal of the Korean Ceramic Society
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• v.23 no.4
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• pp.85-89
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• 1986

Electrical conductivity have been measured as function of temperature in MgO.$P_2O_5$ glasses containing small amounts of water. Conduction was due to the contribution of $H^+$ and the mobility of protons in the glass increased linearly with increasing its concentration. The conductivity was pro-portional to the square of the proton concentration and the activation energy decreased linerly with increasing logarithm of the proton concentration, And $$\sigma$_0$ and $A_0$ was independent of the proton concentration but not on glass compositions.

• Journal of Photoscience
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• v.1 no.1
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• pp.15-23
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• 1994

The absorption and fluorescence spectral properties of piroxicam (PRX) in the hydrogenbonding solvents show the most sensitive dependence on the concentration ranging from 8 x 10$^{_5}$ to 2 x10$^{_5}$ M. These are attributed to both the solvent-mediated ground-state intermolecular proton transfer (GSIerPT) leading to formation of the ground state anion and the excited-state intmmolecular proton transfer (ESIraPT). The concentration dependences of the time-resolved emission kinetics at both room temperature and 77 K have also been investigated. It is shown that in the excited state, the ESIraPT of PRX is the dominant process to form a keto tautomer at the high concentration, whereas at the low concentration the excited-state conformational change of the anion is an additional process leading to formation of a zwitterion. The ESI~PT of PRX in the hydrogenbonding solvent is coupled with the ultrafast excited-state solvent reorganization.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.163-168
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• 1996

Measurements of proton adsorption density have been conducted in preparing alumina suspensions with aqueous solutions of HCL, HNO3, H2SO4 and H3PO4 And effects of anion acid concentration proton adsorption density and solid loading on the viscosity of the alumina suspensions have been investigated. Aqueous solutions of HCl. or HNO3 were suitable for the preparation of highly concentrated suspensions as the generation of surface charge on alumina particles was depressed by the specific adsorption of {{{{ {SO }`_{4 } ^{2- } }} and {{{{ { PO}`_{4 } ^{3- } }} Optimum conditions for maximizing solid loading were dependent upon proton adsorption density and acid concentration.

• Journal of the Korean Ceramic Society
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• v.53 no.5
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• pp.521-528
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• 2016

Kinetic Monte Carlo (KMC) and graph searches show that proton conduction limiting barriers and trajectories in $BaZr_{0.875}Y_{0.125}O_3$ are affected by the presence of other protons. At 1000 K, KMC limiting conduction barriers increase from 0.39 eV to 0.45 eV as the proton number is increased. The proton-proton radial distribution begins to rise at $2{\AA}$ and peaks at $4{\AA}$, which is half the distance expected, based on the proton concentration. Density functional theory (DFT) calculations find proton/proton distances of 2.60 and $2.16{\AA}$ in the lowest energy two-proton configurations. A simple average of the limiting barriers for 7-10 step periodic long range paths found via graph theory at 1100 K shows an increase in activation barrier from 0.32 eV to 0.37 eV when a proton is added. Both KMC and graph theory show that protons can affect each other's pathways and raise the overall conduction barriers.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.315-325
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• 2021

The purpose of this study is to investigate the changes in lipid proton (LP) composition according to the induced obese fatty liver and to use it as basic data for treatment and diagnosis of fatty liver in the future. The phantom study was conducted to identify differences between STEAM and PRESS Pulse sequences in LP concentration. A high-fat diet (60%) was administered to eight Sprague-Dawley rats to induce obesity and fatty liver disease. Baseline magnetic resonance imaging /spectroscopy data were obtained prior to the introduction of high-fat diet, and data acquisition experiments were performed after eight weeks using procedures identical to those used for baseline studies. The six lipid proton metabolites were calculated using LCModel software. The correlation between the fat percentage and each LP, revealed that the methylene protons at 1.3 ppm showed the highest positive correlation. The α-methylene protons to carboxyl and diallylic protons showed negative correlation with fat percentage. The methylene proton showed the highest increase in the LP; however, it constituted only 71.86% of the total LP concentration. The methylene proton plays a leading role in fat accumulation in liver parenchyma.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.301-305
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• 2016

We investigate proton conduction in a nonstoichiometric ${\Sigma}3$ $BaZrO_3$ (210)[001] tilt grain boundary using density functional theory (DFT). We employ the space charge layer (SCL) and structural disorder (SD) models with the introduction of protons and oxygen vacancies into the system. The segregation energies of proton and oxygen vacancy are determined as -0.70 and -0.54 eV, respectively. Based on this data, we obtain a Schottky barrier height of 0.52 V and defect concentrations at 600K, in agreement with the reported experimental values. We calculate the energy barrier for proton migration across the grain boundary core as 0.61 eV, from which we derive proton mobility. We also obtain the proton conductivity from the knowledge of proton concentration and mobility. We find that the calculated conductivity of the nonstoichiometric grain boundary is similar to those of the stoichiometric ones in the literature.

• Journal of the Korean Chemical Society
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• v.38 no.2
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• pp.129-135
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• 1994

Acyclic polyether dicarboxylic acid have been studied as metal cation carriers in a bulk liquid membrane system. The proton-ionizable ligands feature allows the coupling of a cation transport to reverse proton transport. This feature offers promise for the effective separation and concentration of metal cations with the metal cation transport being driven by a pH gradient. Metal cation transport increased regularly with increasing hydroxide($H^-$) concentration of source phase and with proton($H^+$) concentration of receiving phase. Competitive transport by the acyclic polyether dicarboxylic acids is selective for calcium ion over other alkaline-earth cations.

• Progress in Medical Physics
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• v.12 no.1
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• pp.31-39
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• 2001

NMR spectroscopy enables us to measure the molar concentration of the metabolites in the organisms, and this technique is the only method to measure the concentration non-invasively. The proton NMR spectroscopy has been used to study the biochemical changes in human as well as in animal brain. MRI uses the proton densities and its relaxation times for reconstructing images, but MRS gives the biochemical changes inside the body. NMR spectroscopy could provide the information which MRI and CT could not, and this makes NMR spectroscopy more useful in diagnosing diseases. This study was tried to develop the quantitation of the molar concentration of the metabolites in the brain using the proton MR spectroscopy. The spectra of each metabolites was obtained, and the proton MR spectra was obtained from the insula gray matter areas of the 16 volunteers. And this spectra was analyzed to estimated the molar concentrations of the metabolites in the region. The results showed the very similar to those of the others.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.248-259
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• 2014

Acceptor-doped cerium pyrophosphates have shown significant proton conductivity of > $10^{-2}Scm^{-1}$ in the range of $100-300^{\circ}C$ and are considered promising candidates for use as electrolytes in proton-conducting, ceramic electrolyte fuel cells (PCFCs). But, cerium pyrophosphates themselves do not have structural protons, and protons incorporate into their material bulk only as impurities on exposure to a hydrogen-containing atmosphere. However, proton incorporation and proton conduction in these materials are expected to be affected by factors such as the nature (ionic size and charge) and concentration of the aliovalent dopant, processing history (synthesis route and microstructure), and the presence of residual phosphorous phosphate ($P_mO_n$) phases. An exact understanding of these aspects has not yet been achieved, leading to large differences in the magnitude of proton conductivity of cerium pyrophosphates reported in various studies. Herein, we systematically address some of these aspects, and present an overview of factors affecting proton conductivity inacceptor-doped $CeP_2O_7$.

• Journal of Electrochemical Science and Technology
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• v.9 no.2
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• pp.99-108
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• 2018

Proton exchange membrane (PEM) water electrolysis systems offer several advantages over traditional technologies including higher energy efficiency, higher production rates, and more compact design. In this study, all the experiments were performed with a self-designed PEM electrolyser operated at 1 atm and $25^{\circ}C$. Two types of electrolyte were used: (i) potassium hydroxide (KOH), and (ii) sulfuric acid ($H_2SO_4$). In the experiments, the voltage, current, and time were measured. The concentration of the electrolyte significantly affected the electrolyser performance. Overall the best case was with 15 wt% $H_2SO_4$ at the anode channel and 20 wt% at the cathode channel with. In addition, increasing the difference in concentration of the sulfuric acid had an effect on the diffusion. The diffusion flux became larger when the difference in concentration became larger, increasing electrolyser efficiency without the addition of extra energy.