• Membrane Journal
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• v.14 no.1
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• pp.44-52
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• 2004

This paper concerns the development of a cationic polymeric membranes for direct methanol fuel cell. The crosslinked poly(vinyl alcohol) (PVA) membranes with poly(acrylic acid-co-maleic acid) (PAM) and hydroquinonesulfonic acid (HQSA) as the crosslinking agents were prepared according to the amount of crosslinking agents. The resulting membranes were characterized in terms of methanol permeability, proton conductivity, water content and ion exchange capacity. The methanol permeability and proton conductivity increased with increasing PAM content up to 9 wt% and then decreased. This trend is considered the effect of the cross linking rather than the introduction of hydrophilic groups. When the HQSA contents were varied, no interesting increases of proton conductivity, water content and ion exchange capacity were found.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.122-133
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• 2016

While ion beams are widely used in plant breeding, little is known about the sensitivity of Lavandula angustifolia (lavender) to ionizing radiation. To compare the biological effects of different types of ionizing radiation on the germination and survival rates of lavender, we exposed lavender seeds to gamma rays, 3 MeV electron beams, and 1.89 MeV proton ion beams. We observed that the seed germination rate decreased with increasing dosages of all three types of ionizing radiation. The malformation rate of lavender seedlings exposed to electron beams and gamma rays increased with increasing radiation dosage. By contrast, the effect of the accelerated proton beams on the malformation rate was negatively correlated with the dosage used. The survival rate of lavender seedlings exposed to the three types of ionizing radiation decreased in a dose-dependent manner. In addition, the survival rate of seedlings irradiated with proton and electron beams decreased more slowly than did that of seedlings irradiated with gamma rays. The half-lethal dose of gamma rays, electron beams, and proton beams was determined to be 48.1 Gy, 134.3 Gy, and 277.8 Gy, respectively, and the most suitable proton-ion energy for lavender seeds in terms of penetration depth was determined to be 5 MeV. These findings provide valuable information for the breeding of lavender by radiation mutation.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.64-64
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• 2010

Ice film surfaces were examined by using the reactive ion scattering (RIS) of low energy (<35 eV) cesium ion beams. Neutral molecules (X) on the surface were detected in the form of cesium-molecule ion clusters (CsX+). Ionic species on the surface were desorbed from the surface via a low energy sputtering (LES) process below the threshold energy of secondary ion emission. The RIS and LES methods allowed us to study the H/D exchange reactions between H2O and D2O molecules on the surface and the associated proton transfer mechanisms. Specifically, H/D exchange kinetics was examined for D2O ice films (~10 BL) covered with a small amount of H2O (<0.5 BL), in the presence or absence of HCl adsorbates which provided excess protons on the surface.

• Korean Journal of Metals and Materials
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• v.49 no.12
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• pp.977-982
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• 2011

Migration and interaction of multi-protons in a zinc-doped barium zirconate (Zn-doped $BaZrO_3$) super cell were investigated using a density functional theory. O ions in the super cell form interconnected octahedrons with Zr or Zn ions positioned in their centers and Ba ions positioned among the eight octahedrons. When one proton was added to the super cell, the energy barrier of 0.80 eV for proton transfer from the first to second nearest O ion sites from the Zn ion reached its highest value. When two protons were added to the super cell, the two protons preferred the first nearest O ions from the Zn ion. The two protons were accommodated by pushing the neighboring Zn ion further away from the center of the octahedron. Energy barriers for proton transfer from the Zn-octahedron to the neighboring Zr-octahedron were spread in the range of 0.36 ~ 1.02 eV.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.847-849
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• 2001

The OSS2(Ojame-Shavitt-Singer 2)[L. Ojame et al., J. Chem. Phys. 109, 5547 (1998)] model as a dissociable water model is examined in order to study the dynamics of H+ in water. MD simulations for 216 water system, 215 water + H+ ion system, and 215 water + OH- ion system using the OSS2 model at 298.15 K with the use of Ewald summation are carried out. The calculated O-H radial distribution functions for these systems are essentially the same and are in very good agreement with that obtained by Ojame.

• Rapid Communication in Photoscience
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• v.2 no.2
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• pp.60-63
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• 2013

Rhodopsins belong to a family of membrane-embedded photoactive retinylidene proteins. One opsin gene was isolated from ${\beta}$-proteobacterium (IMCC9480) which had been collected at the North Pole. It is very similar to Xanthorhodopin (XR) of HTCC2181. In this study, we carried out basic characterization of the rhodopsin. It has ${\lambda}max$ of 536, 554, and 546 nm at pH 4.0, 7.0, and 10.0, respectively. Since the pKa of its proton acceptor is around 6.27, we measured its proton pumping activity and photocycling rate at pH 8.0. It has a typical proton acceptor (D99) and donor (E110) which mediate proton translocation from intracellular to extracellular region when deduced from the sequence alignments. On the basis of in vitro proton pumping activity, it was proposed to have fast photocycling rate with M and O intermediates, indicating that it is a typical ion-pumping rhodopsin. Since the XR has not yet been expressed in any other heterologous expression system, we tried to get much more information about the XR through the XR-homologue rhodopsin.

• Membrane Journal
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• v.21 no.3
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• pp.270-276
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• 2011

A nascent membrane was prepared by using the solution evaporation method with a solution of sPEEK, EdAn (cross-linking reagent), and PEA (grafting reagent) in DMAc. Then, after the imination and sulfonation process the cross-linked and grafted ion-exchange membrane, CG-sPEEK, was obtained. The sulfonation and imination reactions were confirmed by FTIR analysis. In order to evaluate the possibility of prepared membrane for the use of an ion-exchange membrane in PEMFC, proton conductivity, water uptake and volume change were measured and compared with a commercial membrane, Nafion 115. It was revealed that since the proton conductivity (0.17 S/cm) of prepared membrane were much higher than those of Nafion 115 (0.10 S/cm) the prepared membrane could be used for the ion-exchange membrane in PEMFC. However, the high water uptake (130%) of CG-sPEEK should be reduced for the dimension stability.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.861-868
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• 1996

Skeletal isomerization reaction known as exothermic reaction shows possible maximum yield of i-butene from n-butene at $110^{\circ}C$ over $Pt/MoO_3/SiO_2$. Compared with conventional catalyst such as silica, zeolite, alumina etc., $Pt/MoO_3/SiO_2$ demonstrates higher yield while by-products except 2-butene do not form. Faster H spillover rate over $Pt/MoO_3/SiO_2$ is demonstrated via isothermal reduction experiment at $110^{\circ}C$ compared to the rate over $Pt/MoO_3/Al_2O_3$. Overall isomerization rates are proportional to higher spillover rates from Pt onto $MoO_3$ surface. The skeletal isomerization reaction is composed of two elementary steps. First, carbonium ion formation over Pt crystallites by H spillover. Second, carbenium ion formation over $MoO_3$ followed by formation of i-butene. Moreover, it is suggested that H spillover step from Pt surface onto $MoO_3$ is assumed to be the rate determining step and control the overall isomerization rate.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.24-29
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• 2017

A fluorinated polybenzimidazole (FPBI) was synthesized from 3,3-diaminobenzidine (DAB) of tetraamine, 2,2-bis(4-carboxyphenyl)hexafluoropropane of aromatic biscarboxylic acid, and 4,4-sulfonyldibenzoic acid of aromatic biscarboxylic acid in polyphosphoric acid (PPA). A FPBI was easily cast and made into clear films. The structure of condensation polymers and corresponding membranes were analyzed using GPC (gel permeation chromatography), $^1H$-NMR ($^1H$ nuclear magnetic resonance) and FT-IR (fourier transform infrared). TGA (thermogravimetric analysis) analysis showed that the prepared membranes were thermally stable, so that elevated temperature fuel cell operation would be possible. The proton conductivity of the FPBI membranes increased with increasing temperatures in the polymer. A FPBI membrane has a maximum ion conductivity of 45 mS/cm at $90^{\circ}C$ and 100% relative humidity.

• Progress in Medical Physics
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• v.33 no.4
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• pp.108-113
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• 2022

Purpose: Proton therapy has been used for optimal cancer treatment by adapting its Bragg-peak characteristics. Recently, a tissue-sparing effect was introduced in ultrahigh-dose-rate (FLASH) radiation; the high-energy transmission proton beam is considered in proton FLASH therapy. In measuring high-energy/ultrahigh-dose-rate proton beam, Faraday Cup is considered as a dose-rate-independent measurement device, which has been widely studied. In this paper, the feasibility of the simply designed Faraday Cup (Poor Man's Faraday Cup, PMFC) for transmission proton FLASH therapy is investigated. Methods: In general, Faraday cups were used in the measurement of charged particles. The simply designed Faraday Cup and Advanced Markus ion chamber were used for high-energy proton beam measurement in this study. Results: The PMFC shows an acceptable performance, including accuracy in general dosimetric tests. The PMFC has a linear response to the dose and dose rate. The proton fluence was decreased with the increase of depth until the depth was near the proton beam range. Regarding secondary particles backscatter from PMFC, the effect was negligible. Conclusions: In this study, we performed an experiment to investigate the feasibility of PMFC for measuring high-energy proton beams. The PMFC can be used as a beam stopper and secondary monitoring system for transmission proton beam FLASH therapy.