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Yagihara, Shin; Miura, Norihiko; Hayashi, Yoshihito; Miyairi, Hidenori; Asano, Megumi; Yamada, Gouji; Shinyashiki, Naoki; Mashimo, Satoru; Umehara, Toshihiro; Tokita, Maysayuki; Naito, Satoru; Nagahama, Tohru; Shiotsubo, Masami

doi:10.1023/a:1010162025428

Cited by 16 publications

(24 citation statements)

References 30 publications

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“…However, it is not easy to characterize dynamic behaviors especially in the high frequency region because of two major difficulties in observation and analytical techniques in treatments of fluctuations of dynamics at high frequencies. These difficulties have been solved with improvements of measuring techniques with system stability and effective electrodes [9] used at high frequency measurements, and a development of the fractal analysis [10,11,12] has relieved the lack of analytical techniques for a treatment of dynamics fluctuations. The developments in electrodes usually require new designs and those examinations with actual measurements.…”

Section: Introductionmentioning

confidence: 99%

Physical Meanings of Fractal Behaviors of Water in Aqueous and Biological Systems with Open-Ended Coaxial Electrodes

Yagihara

Kita

Shinyashiki

et al. 2019

Sensors

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The dynamics of a hydrogen bonding network (HBN) relating to macroscopic properties of hydrogen bonding liquids were observed as a significant relaxation process by dielectric spectroscopy measurements. In the cases of water and water rich mixtures including biological systems, a GHz frequency relaxation process appearing at around 20 GHz with the relaxation time of 8.2 ps is generally observed at 25 °C. The GHz frequency process can be explained as a rate process of exchanges in hydrogen bond (HB) and the rate becomes higher with increasing HB density. In the present work, this study analyzed the GHz frequency process observed by suitable open-ended coaxial electrodes, and physical meanings of the fractal nature of water structures were clarified in various aqueous systems. Dynamic behaviors of HBN were characterized by a combination of the average relaxation time and the distribution of the relaxation time. This fractal analysis offered an available approach to both solution and dispersion systems with characterization of the aggregation or dispersion state of water molecules. In the case of polymer-water mixtures, the HBN and polymer networks penetrate each other, however, the HBN were segmented and isolated more by dispersed and aggregated particles in the case of dispersion systems. These HBN fragments were characterized by smaller values of the fractal dimension obtained from the fractal analysis. Some examples of actual usages suggest that the fractal analysis is now one of the most effective tools to understand the molecular mechanism of HBN in aqueous complex materials including biological systems.

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Section: Introductionmentioning

confidence: 99%

Physical Meanings of Fractal Behaviors of Water in Aqueous and Biological Systems with Open-Ended Coaxial Electrodes

Yagihara

Kita

Shinyashiki

et al. 2019

Sensors

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“…[23][24][25] In particular, analysis of hydrated C-S-H gel by 1 H (proton) NMR time, which is sensitive to water dynamics, has shown three components of hydration water in cement pastes (free water, water adsorbed into hydration products, and located within hydrates), in agreement with most of the structural models. In addition, and also to analyze the distribution of water molecules in this complex material, several researchers [26][27][28][29][30] have studied the dielectric response of cement-based materials mainly in the high-frequency range (10 4 -10 9 Hz) but also in the lowfrequency range 31 (10 −2 -10 6 Hz) at room temperatures or higher. However, to our knowledge, dielectric studies at subzero temperatures are missing in the literature.…”

Section: Introductionmentioning

confidence: 99%

Effect of hydration on the dielectric properties of C-S-H gel

Cerveny

Arrese-Igor²,

Dolado³

et al. 2011

The Journal of Chemical Physics

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The behavior of water dynamics confined in hydrated calcium silicate hydrate (C-S-H) gel has been investigated using broadband dielectric spectroscopy (BDS; 10(-2)-10(6) Hz) in the low-temperature range (110-250 K). Different water contents in C-S-H gel were explored (from 6 to 15 wt%) where water remains amorphous for all the studied temperatures. Three relaxation processes were found by BDS (labeled 1 to 3 from the fastest to the slowest), two of them reported here for the first time. We show that a strong change in the dielectric relaxation of C-S-H gel occurs with increasing hydration, especially at a hydration level in which a monolayer of water around the basic units of cement materials is predicted by different structural models. Below this hydration level both processes 2 and 3 have an Arrhenius temperature dependence. However, at higher hydration level, a non-Arrhenius behavior temperature dependence for process 3 over the whole accessible temperature range and, a crossover from low-temperature Arrhenius to high-temperature non-Arrhenius behavior for process 2 are observed. Characteristics of these processes will be discussed in this work.

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“…TDR measuring system equipped a sampling head (HewlettPackard 54121 A) and a mainframe of digitizing oscilloscope (Hewlett-Packard 54121B), covered the frequency range from 10 MHz to 20 GHz. Details of TDR were described in former literatures [5,[11][12][13]. IMA (Hewlett-Packard 4291A) and LCR meter (Hewlett-Packard 4284A) was utilized to cover the range of 1 MHz-1.8 GHz and 20 Hz-1 MHz, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Though this interaction has been extensively investigated so far in various aqueous systems including biological systems [3], recent developments of dielectric spectroscopy bring more precise explanations of physicochemical properties and functions in terms of dynamical structures of molecular complex systems. Especially developments of dielectric spectroscopy in the microwave frequency region [4,5] and lHz frequency region [1,2] expand the techniques of BDS.…”

Section: Introductionmentioning

confidence: 99%