• Korean Chemical Engineering Research
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• 제57권3호
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• pp.338-343
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• 2019

고분자전해질 연료전지에서 전해질막의 물이동과 함수율은 고분자막의 성능에 많은 영향을 미친다. 본 연구에서는 간단한 방법에 의해 물이동에 관한 고분자막의 물성(전기삼투계수, 물 확산계수)을 측정하고 이들을 이용해 막을 통한 물의 이동량과 이온전도도를 모델식에 의해 모사한 후 실험값과 비교하였다. 물이동의 구동력은 전기삼투와 확산만이 라고 본 1차원 정상상태 지배방정식을 매트랩으로 수치해석하였다. $144{\mu}m$ 두께의 고분자막의 전기삼투계수를 수소펌핑셀에서 구한 결과 1.11을 얻었다. 물확산계수를 상대습도의 함수로 나타냈고 물확산에 대한 활성화에너지는 $2,889kJ/mol{\cdot}K$였다. 이들 계수를 적용해 모사한 물이동량과 이온전도도 결과는 실험값과 잘 일치함을 보였다.

• 멤브레인
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• 제17권1호
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• pp.37-43
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• 2007

크로노포텐시오미터(CP)와 전류-전압곡선(I-V)을 사용하여 음/양 이온 교환 층의 영향을 하전 모자이크 막에서 조사하였다. 역시 전해질과 음/양이온의 계면에서 이온수송을 실험하였다. 결과 음/양이온 교환 막은 전류범위에서 점점 전압강하가 나타났고, 특히 저 농도의 KCl 전위는 일정하였다. 한편 복합 하전 모자이크 막은 여러 전해질 수용액의 종류와 농도에 관계없이 전위의 변화는 없었다. CP와 I-V의 측정은 이온교환 막 계면에서 일어나는 이온수송에 대한 기초해석으로 대단히 유효하였다.

• ALGAE
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• 제36권4호
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• pp.315-326
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• 2021

Ion channels are membrane protein complexes mediating passive ion flux across the cell membranes. Every organism has a certain set of ion channels that define its physiology. Dinoflagellates are ecologically important microorganisms characterized by effective physiological adaptability, which backs up their massive proliferations that often result in harmful blooms (red tides). In this study, we used a bioinformatics approach to identify homologs of known ion channels that belong to 36 ion channel families. We demonstrated that the versatility of the dinoflagellate physiology is underpinned by a high diversity of ion channels including homologs of animal and plant proteins, as well as channels unique to protists. The analysis of 27 transcriptomes allowed reconstructing a consensus ion channel repertoire (channelome) of dinoflagellates including the members of 31 ion channel families: inwardly-rectifying potassium channels, two-pore domain potassium channels, voltage-gated potassium channels (K_v), tandem K_v, cyclic nucleotide-binding domain-containing channels (CNBD), tandem CNBD, eukaryotic ionotropic glutamate receptors, large-conductance calcium-activated potassium channels, intermediate/small-conductance calcium-activated potassium channels, eukaryotic single-domain voltage-gated cation channels, transient receptor potential channels, two-pore domain calcium channels, four-domain voltage-gated cation channels, cation and anion Cys-loop receptors, small-conductivity mechanosensitive channels, large-conductivity mechanosensitive channels, voltage-gated proton channels, inositole-1,4,5-trisphosphate receptors, slow anion channels, aluminum-activated malate transporters and quick anion channels, mitochondrial calcium uniporters, voltage-dependent anion channels, vesicular chloride channels, ionotropic purinergic receptors, animal volage-insensitive cation channels, channelrhodopsins, bestrophins, voltage-gated chloride channels H⁺/Cl^- exchangers, plant calcium-permeable mechanosensitive channels, and trimeric intracellular cation channels. Overall, dinoflagellates represent cells able to respond to physical and chemical stimuli utilizing a wide range of G-protein coupled receptors- and Ca²⁺-dependent signaling pathways. The applied approach not only shed light on the ion channel set in dinoflagellates, but also provided the information on possible molecular mechanisms underlying vital cellular processes dependent on the ion transport.

• 열처리공학회지
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• 제35권4호
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• pp.193-202
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• 2022

Manholes and underground spaces are installed to manage the buried heat transport pipes of the district heating system, and the corrosion damage of the equipment placed in this space often occurs. The purpose of this work is to identify locations with a high risk of corrosion damage in the air vent and to establish preventive measures based on precise analysis via sampling of heat transport pipes and air vents that have been used for about 30 years. The residual thickness of the air vent decreased significantly by reaching ~1.1 mm in thickness, and locations of 60~70 mm away from a transport pipe were the most vulnerable to corrosion. The energy dispersive X-ray spectroscopy (EDS) analysis was performed in the corroded oxides, and it was found that chloride ion was contained in the corrosion products. Anodic polarization tests were carried out on the air vent materials (SPPS250, SS304) with varying the amounts of chloride ions at two different temperatures (RT, 80℃). The higher concentration of chloride ions and temperature are, the lower corrosion resistances of both alloys are.

• Journal of Korean Vacuum Science & Technology
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• 제6권2호
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• pp.97-100
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• 2002

NaEr(WO$_4$)$_2$ is a new laser material. The planar optical waveguide was formed in NaEr(WO$_4$)$_2$ crystal by 2.6 MeV He$^{+}$ ion implantation at doses of 1.0-1.5 $\times$ 10$^{16}$ ions/cm$^2$ at room temperature. The effective refractive indices of the dark modes were measured using the prism coupling method. foul n modes and five TM modes were observed in the waveguide. The refractive index profiles were analyzed using the reflectivity calculation method (RCM). The influence of heat treatment at moderate temperature on the refractive index profiles of the waveguide was also investigated. We used the TRIM'98 (Transport of ton in Matter) code to simulate the damage profile in the NaEr(WO$_4$) crystal by 2.6 MeV He$^{+}$ion implantation which is helpful for a better understanding of the waveguide formation.ion.

• 공업화학
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• 제9권3호
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• pp.435-439
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• 1998

페녹시기와 트라이풀루오르에톡시기가 함께 치환된 포스파젠 고분자를 기초로 한 새로운 형태의 이온교환 분리막 재질을 제조하였다. 합성된 고분자의 구조를 핵자기 공명 분석기, 적외선 흡광 분석기, 원소 분석기와 겔침투 분석기를 통해 확인하였다. 기본 포스파젠 분리막은 친수성과 이온 투과성을 높이기 위해 술폰화시켰다. $[NP(OC_6H_4SO_3H)_{1.58}(OCH_2CF_3)_{0.42}]_n$으로부터 얻은 분리막을 상용 분리막과 비교한 결과 매우 뛰어난 이온운반율, 면적 저항 및 이온교환용량을 나타내었다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.167-176
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• 2006

In this paper we show that solutions of the nonlinear Nernst-Planck equation possesses the quadruple-layer structure near the interface when the electrolyte receives a high frequency forcing such as a high-frequency alternating current. Very near to the interface wall, the well-known, classical Stern layer exists. Near to the Stern layer we have the secondly thin layer (to be called inner layer in this paper) where the ion concentrations behave under the same frequency as the external forcing. However, in this layer, the positive and negative ion concentrations develop with the time phase 180-degree different from each other. Next to this second layer, we have the third layer (called middle layer) in which two ion concentrations change with the time period double the forcing, and both concentrations behave in the same time phase. In the outermost layer, i.e. the forth layer, (called outer layer) the ion concentrations show the same-phase development as the third one but decaying very slowly in time. Our assertion is mostly based on the 1-D numerical simulation for the Nernst-Planck equation under a high frequency AC field assuming that the quadruple layer is very thin compared with the length scale representative of the bulk region.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1860-1865
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• 2019

The confinement degradation of the energetic particles during RMP would be a key issue in success of realizing the successful energy production using fusion plasma, because a 3.5 MeV energetic alpha particle should be able to sustain the burning plasma after the ignition. As KSTAR recent results indicate the generation of high-performance plasma(${\beta}_p{\sim}3$), the confinement of the energetic particles is also an important key aspect in neutral beam driven plasma. In general, the measured absolute value of the neutron intensity is generally used for to estimating the confinement time of energetic particles by comparing it with the theoretical value based on transport calculations. However, the availability of, but for its calculation process, many accurate diagnostic data of plasma parameters such as thermal and incident fast ion density, are essential to the calculation process. In this paper, the time evolution of the neutron signal from an He3 counter during the beam blank has permitted to facilitate the estimation of the slowing down time of energetic particles and the method is applied to investigate the fast ion effect on ELM suppressed KSTAR plasma which is heated by high energy deuterium neutral beams.

• Advances in concrete construction
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• 제4권4호
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• pp.305-317
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• 2016

Porous materials such as concrete could be subjected to aggressive ions transport. Durability of cement paste is extremely depended on water and ions penetration into its interior sections. These ions transport could lead different damages depending on reactivity of ions, their concentrations and diffusion coefficients. In this paper, chloride diffusion process in cement hydrates is simulated at atomistic scale using molecular dynamics. Most important phase of cement hydrates is calcium silicate hydrate (C-S-H). Tobermorite, one of the most famous crystal analogues of C-S-H, is used as substrate in the simulation model. To conduct simulation, a nanopore is considered in the middle of simulation cell to place water molecules and aggressive ions. Different chloride salts are considered in models to find out which one is better for calculation of the transport properties. Diffusion coefficients of water molecules and chloride ions are calculated and validated with existing analytical and experimental works. There are relatively good agreements among simulation outputs and experimental results.

• 대한약리학회:학술대회논문집
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• 대한약리학회 2006년도 The 6th Congress of the Federation of Asian and Oceanian Physiological Societies
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• pp.90.2-90.2
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• 2006