An allometric smoothing function to describe the relation between otolith and somatic growth over the lifespan of walleye pollock (Theragra chalcogramma)

We propose a new equation to describe the relation between otolith length (OL) and somatic length (fork length [FL]) of fish for the entire lifespan of the fish. The equation was developed by applying a mathematical smoothing method based on an allometric equation with a constant term for walleye pollock (Theragra chalcogramma) —a species that shows an extended longevity (>20 years). The most appropriate equation for defining the relation between OL and FL was a four-phase allometric smoothing function with three inflection points. The inflection points correspond to the timing of settlement of walleye pollock, changes in sexual maturity, and direction of otolith growth. Allometric smoothing functions describing the relation between short otolith radius and FL, long otolith radius and FL, and FL and body weight were also developed. The proposed allometric smoothing functions cover the entire lifespan of walleye pollock. We term these equations “allometric smoothing functions for otolith and somatic growth over the lifespan of walleye pollock.

Static capacitance at the electrochemical liquid-liquid interface between ionic liquids and eutectic Ga-In alloy measured using the pendant drop method

Static differential capacitance (Cdc) at the liquid-liquid interface between ionic liquids (ILs) and eutectic Ga-In alloy (EGaIn) has been measured using the pendant drop method for two ILs: 1-ethyl-3-methylimidazolium tetrafluoroborate ([C₂mim⁺]BF₄⁻) and 1-octyl-3-methylimidazolium bis(nonafluorobutanesulfonyl)amide ([C₈mim⁺][C₄C₄N⁻]). The potentials of zero charge for the IL|EGaIn interfaces are shifted compared with the IL|Hg interfaces with an amount that can be considered by the difference in the work functions of EGaIn and Hg. The measured Cdc at the [C₂mim⁺]BF₄⁻|EGaIn interface has well reproduced the camel-shape potential dependence of Cdc at the Hg interface of the same IL at the negatively charged potential region. This suggests that there are little specific interaction between the IL ions with EGaIn and Hg. The [C₈mim⁺][C₄C₄N⁻]|EGaIn has been compared with the [C₈mim⁺]BF₄⁻|Hg interface where IL-cation is the same but IL-anion is different. Also in that case, Cdc is similar to each other at the negatively charged potential region, which means that accumulated C₈mim⁺ ions at the interface mainly govern the Cdc behavior

Relation between Mixing Processes and Properties of Lithium-ion Battery Electrode-slurry

The mixing process of electrode-slurry plays an important role in the electrode performance of lithium-ion batteries (LIBs). The dispersion state of conductive materials, such as acetylene black (AB), in the electrode-slurry directly influences the electronic conductivity in the composite electrodes. In this study, the relation between the mixing process of electrode-slurry and the internal resistance of the composite electrode was investigated in combination with the characterization of the electrode-slurries by the rheological analysis and the alternating current (AC) impedance spectroscopy. Some of the electrode-slurries showed higher value and gentler slope of the dynamic storage modulus in the low-angular-frequency region and higher thixotropic index than the others depending on the way of the mixing process and the AB content, agreeing with the low electronic volume resistivities of the corresponding composite electrodes and the electrode-slurries, which indicates the AB network growth. The results suggested that the low-viscosity state when AB and active electrode material are mixed contributes to the dispersive AB network. (C) The Author(s) 2021. Published by ECSJ

An electric double layer structure and differential capacitance at the electrode interface of tributylmethylammonium bis(trifluoromethanesulfonyl)amide studied using a molecular dynamics simulation

A molecular dynamics simulation at the electrode interface of a quaternary ammonium ionic liquid, tributylmethylammonium bis(trifluoromethanesulfonyl)amide ([N₁₄₄₄⁺][TFSA⁻]), has been performed. Unlike the commonly used cations, such as 1-alkyl-3-methylimidazolium and 1, 1-alkylmethylpyrrolidinium cations, N₁₄₄₄⁺ has multiple long-alkyl groups (three butyl groups). The behavior of ions at the electrode interface, especially these butyl groups, has been investigated. N₁₄₄₄⁺ at the first layer mainly has two types of orientations, lying and standing. The lying orientation is dominant at moderately negative potentials. However, the standing one becomes dominant at the more negative potentials. Due to this orientational change, the number of N₁₄₄₄⁺ increases at the first layer as the potential becomes negative even at the potentials where the anions are completely depleted there. The change in orientation results in the upward deviation of the differential capacitance from the theoretical prediction at the negative potentials. The results suggest that the orientational preference caused by the steric constraint between alkyl groups plays an important role in the behavior of the electric double layer of the ionic liquids

Surface Structure of Quaternary Ammonium-Based Ionic Liquids Studied Using Molecular Dynamics Simulation: Effect of Switching the Length of Alkyl Chains

The surface structure of four quaternary ammonium-based ionic liquids (QaILs) at the QaIL|vacuum interface has been analyzed using molecular dynamics simulation to investigate the effect of switching the length of alkyl chains (k) of the quaternary ammonium cations on the surface structure. These four QaILs are composed of a common anion, bis(trifluoromethanesulfonyl)amide (TFSA⁻), and different cations: butyltrimethylammonium (N₁₁₁₄⁺, k = 1), dibutyldimethylammonium (N₁₁₄₄⁺, k = 2), tributylmethylammonium (N₁₄₄₄⁺, k = 3), and tetrabutylammonium (N₄₄₄₄⁺, k = 4), where k represents the number of butyl chains. All the QaILs show the same features as well-studied imidazolium-based ionic liquids (ILs): the formation of the interfacial ionic layers and the orientational preference that nonpolar parts of ions point to the vacuum phase. The thickness of the first ionic layer decreases with increasing k. This results from two-dimensional nanosegregation between polar and nonpolar parts of ions, where the state of the polar parts changes from the continuous phase for small k to dispersed one for large k because of the enlargement of the nonpolar domain with increasing k. Orientational distributions of the butyl chains of the Qa cations indicate that the orientational preference of the butyl chains pointing to the vacuum phase is weakened with increasing k, especially significantly from k = 1 to 2. Even for k = 4, N₄₄₄₄⁺ still shows the orientational preference in spite of its symmetric structure. A linear relation is found between the interfacial potential differences and the surface densities of the Qa cations, suggesting a possibility to control surface absorptivity of dipolar gas molecules in ILs by changing the cation size

オホーツク海沿岸におけるClione limacina およびLimacina helicinaの出現時期

第6回極域科学シンポジウム[OB] 極域生物圏11月16日（月）　国立極地研究所１階交流アトリウ

Evolution and Reversible Polarity of Multilayering at the Ionic Liquid/Water Interface

Highly correlated positioning of ions underlies Coulomb interactions between ions and electrified interfaces within dense ionic fluids such as biological cells and ionic liquids. Recent work has shown that highly correlated ionic systems behave differently than dilute electrolyte solutions, and interest is focused upon characterizing the electrical and structural properties of the dense electrical double layers (EDLs) formed at internal interfaces. It has been a challenge for experiments to characterize the progressive development of the EDL on the nanoscale as the interfacial electric potential is varied over a range of positive and negative values. Here we address this challenge by measuring X-ray reflectivity from the interface between an ionic liquid (IL) and a dilute aqueous electrolyte solution over a range of interfacial potentials from −450 to 350 mV. The growth of alternately charged cation-rich and anion-rich layers was observed along with a polarity reversal of the layers as the potential changed sign. These data show that the structural development of an ionic multilayer-like EDL with increasing potential is similar to that suggested by phenomenological theories and MD simulations, although our data also reveal that the excess charge beyond the first ionic layer decays more rapidly than predicted

分子動力学シミュレーションおよび界面選択的な実験手法を用いたイオン液体の電気二重層構造の研究

京都大学0048新制・課程博士博士(工学)甲第22458号工博第4719号新制||工||1737(附属図書館)京都大学大学院工学研究科物質エネルギー化学専攻(主査)教授 作花 哲夫, 教授 安部 武志, 教授 阿部 竜学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDGA