35 results on '"Ken-ichiro MURATA"'
Search Results
2. Growth Kinetics of Elementary Spiral Steps on Ice Prism Faces Grown in Vapor and Their Temperature Dependence
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Genki Miyamoto, Akira Kouchi, Ken-ichiro Murata, Ken Nagashima, and Gen Sazaki
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General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2022
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3. Microscopic ordering of supercooled water on the ice basal face
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Kenji Mochizuki, Ken-ichiro Murata, and Xuan Zhang
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Mechanics of Materials ,General Materials Science - Abstract
Growth of ice crystals is ubiquitous around us, but we still do not know what is occurring at the forefront of crystallization. In general, the interfacial structure is inseparably involved in the microscopic ordering during crystal growth. However, despite its importance in nature and technology, the intrinsic role of the interfacial structure in the melt growth of ice remains to be elucidated. Here, using extensive molecular dynamics simulations, we comprehensively explore how supercooled water molecules are incorporated into the ice basal face. Structural and dynamic characterizations of the ice-water interface demonstrate that the ice basal face is sharp at the molecular level and its growth proceeds layer-by-layer through two-dimensional nucleation without any intermediate structures. We further quantify the crossover from layerwise to adhesive growth, called kinetic roughening, with the height difference correlation and the normal growth rate analysis. Moreover, we identify the presence of an ultra-low density water layer in contact with the structural interface, which assists two-dimensional nucleation at a small amount of supercooling without involving any triggers, such as dislocations.
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- 2023
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4. HCl Droplets Induced Bunched Steps on Ice Crystal Surfaces under Atmospheric-Concentration HCl Gas
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Ken-ichiro Murata, Ken Nagashima, and Gen Sazaki
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Ice crystals ,010405 organic chemistry ,Inorganic chemistry ,General Chemistry ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Chemical reaction ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,General Materials Science ,Catalytic ozone ,Hydrogen chloride - Abstract
Surfaces of ice act as sites of various chemical reactions of atmospheric acidic gases, which cause serious environmental issues, such as the catalytic ozone depletion by hydrogen chloride (HCl) ga...
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- 2021
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5. Direct Observation of Bound Water on Cotton Surfaces by Atomic Force Microscopy and Atomic Force Microscopy–Infrared Spectroscopy
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Masato Hoshi, Koichi Nakamura, Ken-ichiro Murata, Takako Igarashi, and Takeshi Kaharu
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musculoskeletal diseases ,animal structures ,Materials science ,Infrared spectroscopy ,macromolecular substances ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,medicine ,Bound water ,Physical and Theoretical Chemistry ,Composite material ,Atomic force microscopy ,technology, industry, and agriculture ,Direct observation ,Stiffness ,equipment and supplies ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,Hardening (metallurgy) ,medicine.symptom ,0210 nano-technology - Abstract
A wet cotton rag becomes stiff after natural drying. We propose a model for this hardening phenomenon, which explains that the stiffness of cotton is caused by a cross-linked network between single fibers, mediated by capillary adhesion of bound water on the surface of cellulose. Here, with the aid of atomic force microscopy and atomic force microscopy-infrared spectroscopy, we reveal the existence of the bound water on the surface of a cotton single fiber under naturally dried conditions. We also find that the hydrogen bonding state of the bound water is distinct from that of the bulk water. Two stretching modes of OH groups are clearly decoupled from each other, which arise from the effects of the air-water (hydrophobic) and water-cellulose (hydrophilic) interfaces. This suggests a possible link between the microscopic nature of the bound water and the macroscopic mechanical behavior of cotton fabrics.
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- 2020
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6. Step-bunching instability of growing interfaces between ice and supercooled water
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Ken-ichiro Murata, Masahide Sato, Makio Uwaha, Fumiaki Saito, Ken Nagashima, and Gen Sazaki
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melt growth ,screw dislocation ,Multidisciplinary ,ice-crystal growth ,in situ observation ,Step-bunching instability - Abstract
金沢大学学術メディア創成センター, Ice-crystal growth in supercooled water is one of the most familiar examples of phase-transition dynamics, playing essential roles in various natural phenomena on Earth. Despite its fundamental importance, the microscopic view at the elementary step level remains elusive. Here, using an advanced optical microscope, we find self-organization of elementary steps during ice-crystal growth, called step-bunching instability (SBI), driven by the competition between step dynamics, interfacial stiffness, and latent heat diffusions. We also find that the SBI transiently induces screw dislocations and resulting spiral growth in the late stage of the growth process. Furthermore, quantitative observations with a two-beam interferometer allow us to obtain insights into the relative importance of the various mechanisms of the step–step interactions. Our finding offers a significant clue to understanding the general mechanism of melt growth beyond ice-crystal growth, inseparably involving several broad research fields, including cryobiological, geophysical, and material branches.
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- 2022
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7. The emergence of drop-type and thin-layer-type quasi-liquid layers on ice crystal surfaces and their thermodynamic origin
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Gen Sazaki, Ken-ichiro Murata, Harutoshi Asakawa, Ken Nagashima, Shunichi Nakatsubo, and Yoshinori Furukawa
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Inorganic Chemistry ,Materials Chemistry ,Condensed Matter Physics - Published
- 2022
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8. Correction to Quasi-Liquid Layers Can Exist on Polycrystalline Ice Thin Films at a Temperature Significantly Lower than on Ice Single Crystals
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Jialu Chen, Takao Maki, Ken Nagashima, Ken-ichiro Murata, and Gen Sazaki
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General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2020
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9. Quasi-Liquid Layers Can Exist on Polycrystalline Ice Thin Films at a Temperature Significantly Lower than on Ice Single Crystals
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Gen Sazaki, Ken-ichiro Murata, Jialu Chen, and Ken Nagashima
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Materials science ,Ice crystals ,010405 organic chemistry ,Liquid water ,Vapour pressure of water ,General Chemistry ,010402 general chemistry ,Condensed Matter Physics ,Laser ,01 natural sciences ,0104 chemical sciences ,law.invention ,law ,Melting point ,General Materials Science ,Grain boundary ,Crystallite ,Thin film ,Composite material - Abstract
Surface melting of ice crystals proceeds below the melting point (0 °C) and forms thin liquid water layers, called quasi-liquid layers (QLLs), which govern a wide variety of phenomena in nature. Hence, many studies have been performed so far; however, the lowest temperature above which QLLs exist on ice crystal surfaces varied from −90 to −1 °C. To reveal the cause of such significant variations, here we show, by laser confocal microscopy combined with Michelson interferometry, the behavior of QLLs on polycrystalline ice thin films that include a large amount of grain boundaries and defects. We found that the QLLs can exist stably on the polycrystalline ice thin films even at −16.2 °C (the lowest temperature adopted in this study), although the QLLs on ice single crystals disappear at temperature lower than −2.4 ± 0.5 °C. These results emphasize the importance of grain boundaries and defects for the presence of QLLs. In addition, we also found that critical water vapor pressure above which the QLLs can gr...
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- 2018
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10. Uptake Mechanism of Atmospheric Hydrogen Chloride Gas in Ice Crystals via Hydrochloric Acid Droplets
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Ken-ichiro Murata, Ken Nagashima, Tetsuya Hama, Gen Sazaki, and Yoshinori Furukawa
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Supersaturation ,Materials science ,010504 meteorology & atmospheric sciences ,Ice crystals ,Evaporation ,Hydrochloric acid ,General Chemistry ,010402 general chemistry ,Condensed Matter Physics ,Mole fraction ,01 natural sciences ,Chemical reaction ,0104 chemical sciences ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,General Materials Science ,Solubility ,Hydrogen chloride ,human activities ,0105 earth and related environmental sciences - Abstract
Surfaces of ice have attracted considerable attention as “reaction sites” where atmospheric gases cause various chemical reactions in nature. Hence, revealing the uptake mechanism of atmospheric gases on/in ice remains an experimental challenge. Here we show the direct observation of ice crystal surfaces by advanced optical microscopy in the presence of hydrogen chloride (HCl) gas, which triggers a series of chemical reactions that cause ozone depletion. We found that the HCl gas induced the appearance of droplets of HCl solution on ice crystal surfaces. Under supersaturated water vapor pressure, the HCl droplets were quickly embedded in the ice crystals during the growth of the ice. In contrast, under undersaturated conditions, the embedded HCl droplets reappeared on the ice crystal surfaces during the evaporation of the ice. We estimated that the mole fraction of HCl incorporated into the ice as the HCl droplets (0.19% at −15 °C) was ten times larger than the solubility of HCl gas in an ice crystal (0.0...
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- 2018
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11. Temperature Dependence of the Growth Kinetics of Elementary Spiral Steps on Ice Basal Faces Grown from Water Vapor
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Gen Sazaki, Shunichi Nakatsubo, Yoshinori Furukawa, Harutoshi Asakawa, Masahiro Inomata, Ken Nagashima, and Ken-ichiro Murata
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MECHANISM ,Materials science ,Growth kinetics ,PHASE ,Analytical chemistry ,02 engineering and technology ,101 ADP FACE ,SIDE BRANCHES ,01 natural sciences ,law.invention ,Optical microscope ,law ,0103 physical sciences ,General Materials Science ,SUPERCOOLED WATER ,Spiral ,010302 applied physics ,Supersaturation ,HABIT CHANGE ,General Chemistry ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,CRYSTALS ,MOLECULAR-SURFACE STRUCTURE ,Kinetic coefficient ,IN-SITU OBSERVATION ,0210 nano-technology ,Water vapor ,PATTERN-FORMATION - Abstract
We measured the velocity Vstep of isolated elementary spiral steps and the distance Leq between adjacent equivalent spiral steps on ice basal faces by advanced optical microscopy. We determined the step kinetic coefficient β from Vstep measured under various supersaturations. We performed similar experiments under various temperatures T, and determined the temperature dependence of β of ice basal faces, for the first time, in the temperature range of −26.0 to −2.7 °C. When −6.2 ≤ T ≤ −2.7 °C, the value of β decreased significantly with decreasing T. In contrast, when −15.0 ≤ T ≤ −6.2 °C, the value of β increased with decreasing T, and had the maximum at T ≈ −15 °C. When −26.0 ≤ T ≤ −15.0 °C, the value of β decreased monotonically with decreasing T. Such complicated temperature dependence of β strongly implies the existence of unknown phenomena in the temperature range examined. To obtain a clue to the complicated behavior of β, we also measured dependence of Leq on surface supersaturation Δμsurf. When −13...
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- 2018
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12. In-situ optical microscopy observation of elementary steps on ice crystals grown in vapor and their growth kinetics
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Gen Sazaki, Masahiro Inomata, Ken-ichiro Murata, Ken Nagashima, Etsuro Yokoyama, Harutoshi Asakawa, Yoshinori Furukawa, and Shunichi Nakatsubo
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Surface diffusion ,Materials science ,Ice crystals ,Scanning electron microscope ,Crystal structure ,Condensed Matter Physics ,law.invention ,Optical microscope ,Differential interference contrast microscopy ,law ,Chemical physics ,Microscopy ,Melting point ,General Materials Science ,sense organs - Abstract
Ice is one of the most abundant materials on the earth's surface, and its growth governs various natural phenomena. Hence, the molecular-level understanding of ice crystal surfaces is crucially important. However, it is generally acknowledged that the molecular-level observation of ice crystal surfaces by ordinary microscopy techniques, such as atomic force microscopy and scanning electron microscopy, is very difficult at temperatures near the melting point (0 °C). To overcome such difficulties, we have developed laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM). We proved that LCM-DIM can visualize individual elementary steps (0.37 nm in thickness) on a basal face by observing two-dimensional nucleation growth. Then we found by LCM-DIM that spiral steps on a basal face exhibit a double-spiral pattern, which can be expected from ice's crystallographic structure. In addition, we revealed that temperature dependence of growth kinetics of elementary spiral steps on a basal face exhibits complicated behaviors, which show the presence of unknown phenomena in the growth kinetics. Furthermore, we proved that surface diffusion of water admolecules on a basal face plays a crucially important role in the lateral growth of elementary steps when the distance between adjacent spiral steps is smaller than 15 µm. These findings will provide a clue for unlocking growth kinetics of ice crystals. In addition, through the use of LCM-DIM much progress has been made in studies on the surface melting of ice and the interaction between ice and atmospheric gasses.
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- 2021
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13. Transmission Electron Microscopy Study of the Morphology of Ices Composed of H2O, CO2, and CO on Refractory Grains
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Kazuyuki Fujita, Naoki Watanabe, Yasuhiro Oba, Masashi Tsuge, Shunichi Nakatsubo, Ken-ichiro Murata, Shogo Tachibana, Tetsuya Hama, Naoki Nakatani, Yuki Kimura, Tomoya Yamazaki, Takashi Shimonishi, Satoshi Okuzumi, Kenji Furuya, Sin-iti Sirono, Akira Kouchi, Hiroshi Hidaka, and Munetake Momose
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Physics ,FOS: Physical sciences ,Sintering ,Astronomy and Astrophysics ,Astrophysics ,Substrate (electronics) ,Astrophysics - Astrophysics of Galaxies ,law.invention ,Amorphous solid ,Crystal ,Crystallinity ,Chemical engineering ,Space and Planetary Science ,Transmission electron microscopy ,law ,Astrophysics of Galaxies (astro-ph.GA) ,Thin film ,Crystallization - Abstract
It has been implicitly assumed that ices on grains in molecular clouds and proto planetary disks are formed by homogeneous layers regardless of their composition or crystallinity. To verify this assumption, we observed the H2O deposition onto refractory substrates and the crystallization of amorphous ices (H2O, CO2, and CO) using an ultra-high-vacuum transmission electron microscope. In the H2O-deposition experiments, we found that three-dimensional islands of crystalline ice (Ic) were formed at temperatures above 130 K. The crystallization experiments showed that uniform thin films of amorphous CO and H2O became three-dimensional islands of polyhedral crystals; amorphous CO2, on the other hand, became a thin film of nano crystalline CO2 covering the amorphous H2O. Our observations show that crystal morphologies strongly depend not only on the ice composition, but also on the substrate. Using experimental data concerning the crystallinity of deposited ices and the crystallization timescale of amorphous ices, we illustrated the criteria for ice crystallinity in space and outlined the macroscopic morphology of icy grains in molecular clouds as follows: amorphous H2O covered the refractory grain uniformly, CO2 nano-crystals were embedded in the amorphous H2O, and a polyhedral CO crystal was attached to the amorphous H2O. Furthermore, a change in the grain morphology in a proto-planetary disk is shown. These results have important implications for the chemical evolution of molecules, non-thermal desorption, collision of icy grains, and sintering., 60 pages, 18 figures, 3 tables, published in ApJ
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- 2021
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14. Link between molecular mobility and order parameter during liquid–liquid transition of a molecular liquid
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Hajime Tanaka and Ken-ichiro Murata
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Phase transition ,Multidisciplinary ,Materials science ,Dielectric ,Activation energy ,Dielectric spectroscopy ,Condensed Matter::Soft Condensed Matter ,Molecular dynamics ,symbols.namesake ,PNAS Plus ,Chemical physics ,Metastability ,symbols ,Raman spectroscopy ,Supercooling - Abstract
Liquid–liquid transition (LLT) is the transformation of one liquid to another via first-order phase transition. For example, LLT in a molecular liquid, triphenyl phosphite, is macroscopically the transformation from liquid I in a supercooled state to liquid II in a glassy state. Reflecting the transformation from the liquid to glassy state, the LLT is accompanied by considerable slowing down of overall molecular dynamics, but little is known about how this proceeds at a molecular level coupled with the evolution of the order parameter. We report such information by performing time-resolved simultaneous measurements of dielectric spectroscopy and phase contrast microscopy/Raman spectroscopy by using a dielectric cell with transparent electrodes. We find that the temporal change in molecular mobility crucially depends on whether LLT is nucleation growth type occurring in the metastable state or SD type occurring in the unstable state. Furthermore, our results suggest that the molecular mobility is controlled by the local order parameter: more specifically, the local activation energy of molecular rotation is controlled by the local fraction of locally favored structures formed in the liquid. Our study sheds light on the temporal change in the molecular dynamics during LLT and its link to the order parameter evolution.
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- 2019
15. How Do Ice Crystals Grow inside Quasiliquid Layers?
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Ken-ichiro Murata, Ken Nagashima, and Gen Sazaki
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Materials science ,Ice crystals ,Layer by layer ,Nucleation ,General Physics and Astronomy ,Crystal growth ,01 natural sciences ,law.invention ,law ,Chemical physics ,0103 physical sciences ,Diffusion (business) ,Crystallization ,010306 general physics ,Supercooling ,Layer (electronics) - Abstract
A microscopic understanding of crystal-melt interfaces, inseparably involved in the dynamics of crystallization, is a long-standing challenge in condensed matter physics. Here, using an advanced optical microscopy, we directly visualize growing interfaces between ice basal faces and quasiliquid layers (QLLs) during ice crystal growth. This system serves as a model for studying the molecular incorporation process of the crystal growth from a supercooled melt (the so-called melt growth), often hidden by inevitable latent heat diffusion and/or the extremely high crystal growth rate. We reveal that the growth of basal faces inside QLLs proceeds layer by layer via two-dimensional nucleation of monomolecular islands. We also find that the lateral growth rate of the islands is well described by the Wilson-Frenkel law, taking into account the slowing down of the dynamics of water molecules interfaced with ice. These results clearly indicate that, after averaging surface molecular fluctuations, the layer by layer stacking still survives even at the topmost layer on basal faces, which supports the kink-step-terrace picture even for the melt growth.
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- 2019
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16. In-situ observation of crystal surfaces by optical microscopy
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Ken Nagashima, Gen Sazaki, Yoshinori Furukawa, and Ken-ichiro Murata
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010302 applied physics ,Interference color ,Polarized light microscopy ,Materials science ,business.industry ,Scanning confocal electron microscopy ,02 engineering and technology ,Polarizing microscopy ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Optical microscopy ,Differential interference contrast microscopy ,01 natural sciences ,Dark field microscopy ,Interference microscopy ,Optics ,0103 physical sciences ,Classical interference microscopy ,Microscopy ,General Materials Science ,Digital holographic microscopy ,0210 nano-technology ,business - Abstract
In this experimental course, attendees will learn how to obtain useful information about growth processes of crystals using ordinary optical microscopes, which are usually available in laboratories. We will demonstrate how thicknesses of crystals can be estimated from interference colors. We will also show in-situ observations of spiral steps and strain distributions by differential interference contrast microscopy and polarizing microscopy, respectively.
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- 2016
17. Direct Visualization of Quasi-Liquid Layers on Ice Crystal Surfaces Induced by Hydrogen Chloride Gas
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Gen Sazaki, Harutoshi Asakawa, Yoshinori Furukawa, Tetsuya Hama, Ken-ichiro Murata, and Ken Nagashima
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Ice crystals ,Chemistry ,Analytical chemistry ,02 engineering and technology ,General Chemistry ,Atmospheric temperature range ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Chemical reaction ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Crystallography ,Adsorption ,Optical microscope ,law ,Amorphous ice ,General Materials Science ,0210 nano-technology ,Hydrogen chloride ,Spectroscopy - Abstract
Surface melting of ice crystals forms quasi-liquid layers (QLLs) on ice surfaces, and affects a wide variety of natural phenomena. Since QLLs enhance various chemical reactions in ice clouds, the formation of QLLs by atmospheric gases has been studied intensively. However, such studies were performed using spectroscopy techniques, which have low spatial resolution. Here we show the first direct visualization of QLLs on ice basal faces in the presence of hydrogen chloride (HCl) gas (model atmospheric gas) by advanced optical microscopy, which can visualize individual 0.37 nm-thick elementary steps on ice crystal surfaces. We found that the HCl gas induced the appearances of QLLs with a droplet shape in the temperature range from −15.0 to −1.5 °C, where no QLL appears in the absence of HCl gas. This result indicates that HCl gas adsorbed on ice crystal surfaces probably changed the surface structure of ice crystals and then induced the subsequent melting of ice surfaces. We also observed the movement, shape...
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- 2016
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18. Appearance and Disappearance of Quasi-Liquid Layers on Ice Crystals in the Presence of Nitric Acid Gas
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Gen Sazaki, Yoshinori Furukawa, Ken Nagashima, Patrick Ayotte, Josée Maurais, and Ken-ichiro Murata
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Materials science ,010504 meteorology & atmospheric sciences ,General Chemical Engineering ,Analytical chemistry ,Liquidus ,010402 general chemistry ,01 natural sciences ,Chemical reaction ,Inorganic Chemistry ,lcsh:QD901-999 ,General Materials Science ,Binary system ,0105 earth and related environmental sciences ,Phase diagram ,optical microscopy ,Aqueous solution ,Ice crystals ,Partial pressure ,Condensed Matter Physics ,0104 chemical sciences ,Melting point ,lcsh:Crystallography ,ice crystals ,quasi-liquid layer ,nitric acid gas - Abstract
The surfaces of ice crystals near the melting point are covered with thin liquid water layers, called quasi-liquid layers (QLLs), which play crucial roles in various chemical reactions in nature. So far, there have been many spectroscopic studies of such chemical reactions on ice surfaces, however, revealing the effects of atmospheric gases on ice surfaces remains an experimental challenge. In this study, we chose HNO3 as a model atmospheric gas, and directly observed the ice basal faces by advanced optical microscopy under partial pressure of HNO3 (~10&minus, 4 Pa), relevant to those found in the atmosphere. We found that droplets (HNO3-QLLs) appeared on ice surfaces at temperatures ranging from &minus, 0.9 to &minus, 0.2 °, C with an increase in temperature, and that they disappeared at temperatures ranging from &minus, 0.6 to &minus, 1.3 °, C with decreasing temperature. We also found that the size of the HNO3-QLLs decreased immediately after we started reducing the temperature. From the changes in size and the liquid&ndash, solid phase diagram of the HNO3-H2O binary system, we concluded that the HNO3-QLLs did not consist of pure water, but rather aqueous HNO3 solutions, and that the temperature and HNO3 concentration of the HNO3-QLLs also coincided with those along a liquidus line.
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- 2020
19. In situ observations of spiral growth on ice crystal surfaces
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Gen Sazaki, Ken-ichiro Murata, and Ken Nagashima
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Coalescence (physics) ,Surface diffusion ,In situ ,Materials science ,Physics and Astronomy (miscellaneous) ,Ice crystals ,Condensed matter physics ,Nucleation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Condensed Matter::Materials Science ,Optical microscope ,law ,otorhinolaryngologic diseases ,General Materials Science ,sense organs ,Dislocation ,Spiral (railway) ,0210 nano-technology - Abstract
The spiral growth of crystals, mediated by their screw dislocations, is a general crystal-growth mechanism observed over a large variety of crystalline solids. Despite its general nature, direct observations of the spiral growth of ice have been rarely reported so far. Here, with the aid of advanced optical microscopy, we succeed in making in situ observations of the perfect spiral growth during the vapor growth of ice. We find that the spiral steps observed are well described by the classical Burton--Cabrera--Frank theory, taking into account surface diffusion of water admolecules between adjacent steps. This is distinct from the dominant growth mode that we have assigned as spiral in our recent studies, which accompanies fluctuations of the adjacent step interval. We also successfully capture the birth of a screw dislocation and the ensuing spiral growth, originating in the lattice mismatch arising from the coalescence of single ice crystals. Furthermore, we demonstrate that the nucleation of quasi-liquid layers (QLLs) takes place at the spiral center immediately after the birth of the dislocation, which suggests a link between screw dislocations and the generation of QLLs near the ice melting point.
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- 2018
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20. Microscopic identification of the order parameter governing liquid–liquid transition in a molecular liquid
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Hajime Tanaka and Ken-ichiro Murata
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Phase transition ,Multidisciplinary ,Number density ,Materials science ,Scattering ,Crystal structure ,computer.software_genre ,Structural evolution ,Liquid state ,Order (biology) ,Chemical physics ,Physical Sciences ,Liquid liquid ,Data mining ,computer - Abstract
A liquid-liquid transition (LLT) in a single-component substance is an unconventional phase transition from one liquid to another. LLT has recently attracted considerable attention because of its fundamental importance in our understanding of the liquid state. To access the order parameter governing LLT from a microscopic viewpoint, here we follow the structural evolution during the LLT of an organic molecular liquid, triphenyl phosphite (TPP), by time-resolved small- and wide-angle X-ray scattering measurements. We find that locally favored clusters, whose characteristic size is a few nanometers, are spontaneously formed and their number density monotonically increases during LLT. This strongly suggests that the order parameter of LLT is the number density of locally favored structures and of nonconserved nature. We also show that the locally favored structures are distinct from the crystal structure and these two types of orderings compete with each other. Thus, our study not only experimentally identifies the structural order parameter governing LLT, but also may settle a long-standing debate on the nature of the transition in TPP, i.e., whether the transition is LLT or merely microcrystal formation.
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- 2015
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21. Liquid-like behavior of UV-irradiated interstellar ice analog at low temperatures
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Iyo Sugawara, H. Hidaka, Yuki Kimura, Naoki Watanabe, Yukiko Endo, Akira Kouchi, Shogo Tachibana, Hisayoshi Yurimoto, Ken-ichiro Murata, Laurette Piani, Tetsuya Hama, Yasuhiro Oba, Hokkaido University [Sapporo, Japan], Department of Earth and Planetary Systems Science [Hiroshima], and Hiroshima University
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Planetesimal ,Materials science ,Astrochemistry ,Interstellar cloud ,ice ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,010502 geochemistry & geophysics ,medicine.disease_cause ,01 natural sciences ,7. Clean energy ,Astrobiology ,0103 physical sciences ,organics ,medicine ,comets ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics::Atmospheric and Oceanic Physics ,Research Articles ,0105 earth and related environmental sciences ,interstellar medium ,Multidisciplinary ,Interstellar ice ,SciAdv r-articles ,Accretion (astrophysics) ,Amorphous solid ,13. Climate action ,Amorphous ice ,Astrophysics::Earth and Planetary Astrophysics ,Ultraviolet ,Research Article ,UV-irradiation - Abstract
UV-irradiated interstellar ice analog behaves like a liquid at 50 to 150 kelvin, below its crystallization temperature., Interstellar ice is believed to be a cradle of complex organic compounds, commonly found within icy comets and interstellar clouds, in association with ultraviolet (UV) irradiation and subsequent warming. We found that UV-irradiated amorphous ices composed of H2O, CH3OH, and NH3 and of pure H2O behave like liquids over the temperature ranges of 65 to 150 kelvin and 50 to 140 kelvin, respectively. This low-viscosity liquid-like ice may enhance the formation of organic compounds including prebiotic molecules and the accretion of icy dust to form icy planetesimals under certain interstellar conditions.
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- 2017
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22. Oscillations and accelerations of ice crystal growth rates in microgravity in presence of antifreeze glycoprotein impurity in supercooled water
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Salvador Zepeda, Shunichi Nakatsubo, Yoshinori Furukawa, Takanori Terasawa, Taro Shimaoka, Gen Sazaki, Harutoshi Asakawa, Takehiko Sone, Haruka Tamaru, Ken Nagashima, Etsuro Yokoyama, Izumi Yoshizaki, and Ken-ichiro Murata
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Convection ,Multidisciplinary ,Materials science ,Ice crystals ,Weightlessness ,Lead (sea ice) ,Ice ,Crystal growth ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Article ,0104 chemical sciences ,Impurity ,Chemical physics ,Antifreeze protein ,Antifreeze ,Antifreeze Proteins ,0210 nano-technology ,Supercooling ,Crystallization ,Water Pollutants, Chemical - Abstract
The free growth of ice crystals in supercooled bulk water containing an impurity of glycoprotein, a bio-macromolecule that functions as ‘antifreeze’ in living organisms in a subzero environment, was observed under microgravity conditions on the International Space Station. We observed the acceleration and oscillation of the normal growth rates as a result of the interfacial adsorption of these protein molecules, which is a newly discovered impurity effect for crystal growth. As the convection caused by gravity may mitigate or modify this effect, secure observations of this effect were first made possible by continuous measurements of normal growth rates under long-term microgravity condition realized only in the spacecraft. Our findings will lead to a better understanding of a novel kinetic process for growth oscillation in relation to growth promotion due to the adsorption of protein molecules and will shed light on the role that crystal growth kinetics has in the onset of the mysterious antifreeze effect in living organisms, namely, how this protein may prevent fish freezing.
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- 2017
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23. Impact of surface roughness on liquid-liquid transition
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Hajime Tanaka and Ken-ichiro Murata
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Length scale ,Spinodal ,liquid-liquid transition ,Materials science ,pattern evolution ,rubbing ,surface effects ,Nucleation ,FOS: Physical sciences ,Nanotechnology ,02 engineering and technology ,Condensed Matter - Soft Condensed Matter ,010402 general chemistry ,01 natural sciences ,Physics::Fluid Dynamics ,Physics::Popular Physics ,Phase (matter) ,Metastability ,Surface roughness ,Condensed Matter - Statistical Mechanics ,Research Articles ,Condensed Matter - Materials Science ,Mesoscopic physics ,Multidisciplinary ,integumentary system ,Statistical Mechanics (cond-mat.stat-mech) ,digestive, oral, and skin physiology ,SciAdv r-articles ,Materials Science (cond-mat.mtrl-sci) ,Disordered Systems and Neural Networks (cond-mat.dis-nn) ,Condensed Matter - Disordered Systems and Neural Networks ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,humanities ,0104 chemical sciences ,Rubbing ,body regions ,Condensed Matter::Soft Condensed Matter ,Chemical physics ,Soft Condensed Matter (cond-mat.soft) ,wedge filling ,0210 nano-technology ,Research Article - Abstract
Liquid-liquid transition (LLT) in single-component liquids is one of the most mysterious phenomena in condensed matter. So far this problem has attracted attention mainly from the purely scientific viewpoint. Here we report the first experimental study on an impact of surface nano-structuring on LLT by using a surface treatment called rubbing, which is the key technology for the production of liquid crystal displays. We find that such a rubbing treatment has a significant impact on the kinetics of liquid-liquid transition (LLT) of an isotropic molecular liquid, triphenyl phosphite. For a liquid confined between rubbed surfaces, surface-induced barrier-less formation of the liquid II phase is observed even in a metastable state, where there should be a barrier for nucleation of the liquid II phase in bulk. Thus, surface rubbing of substrates not only changes the ordering behavior, but also accelerates the kinetics significantly. This spatio-temporal pattern modulation of LLT can be explained by a wedge filling transition and the resulting drastic reduction of the nucleation barrier. However, this effect completely disappears in the unstable (spinodal) regime, indicating the absence of the activation barrier even for bulk LLT. This confirms the presence of nucleation-growth-type and spinodal-decomposition-type LLT, supporting that LLT is truly a first-order transition with criticality. Our finding also opens up a new way to control the kinetics of LLT of a liquid confined in a solid cell by structuring its surface on a mesoscopic lengthscale, which may contribute to making LLT useful for micro-fluidics and other industrial applications., Comment: 14 pages, 5 figures in the main text; 2 pages, 2 figures in Supplementary Materials
- Published
- 2017
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24. Crystal-plane-dependent effects of antifreeze glycoprotein impurity for ice growth dynamics
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Ken Nagashima, Salvador Zepeda, Gen Sazaki, Shunichi Nakatsubo, Yoshinori Furukawa, and Ken-ichiro Murata
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Materials science ,Ice crystals ,General Mathematics ,Dynamics (mechanics) ,General Engineering ,General Physics and Astronomy ,Crystal growth ,Articles ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Impurity ,Chemical physics ,Antifreeze ,Cryosphere ,Astrophysics::Earth and Planetary Astrophysics ,0210 nano-technology ,Supercooling ,Physics::Atmospheric and Oceanic Physics ,Earth (classical element) - Abstract
An impurity effect on ice crystal growth in supercooled water is an important subject in relation to ice crystal formation in various conditions in the Earth's cryosphere regions. In this review, we consider antifreeze glycoprotein molecules as an impurity. These molecules are well known as functional molecules for controlling ice crystal growth by their adsorption on growing ice/water interfaces. Experiments on free growth of ice crystals in supercooled water containing an antifreeze protein were conducted on the ground and in the International Space Station, and the normal growth rates for the main crystallographic faces of ice, namely, basal and prismatic faces, were precisely measured as functions of growth conditions and time. The crystal-plane-dependent functions of AFGP molecules for ice crystal growth were clearly shown. Based on the magnitude relationship for normal growth rates among basal, prismatic and pyramidal faces, we explain the formation of a dodecahedral external shape of an ice crystal in relation to the key principle governing the growth of polyhedral crystals. Finally, we emphasize that the crystal-plane dependence of the function of antifreeze proteins on ice crystal growth relates to the freezing prevention of living organisms in sub-zero temperature conditions. This article is part of the theme issue ‘The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets’.
- Published
- 2019
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25. Thermodynamic origin of surface melting on ice crystals
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Gen Sazaki, Ken-ichiro Murata, Yoshinori Furukawa, Ken Nagashima, and Harutoshi Asakawa
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Transient state ,Supersaturation ,Multidisciplinary ,Ice crystals ,Chemistry ,Thermodynamics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,law.invention ,Wetting transition ,law ,Metastability ,Commentaries ,0103 physical sciences ,Sublimation (phase transition) ,Wetting ,010306 general physics ,0210 nano-technology ,Faraday cage - Abstract
Since the pioneering prediction of surface melting by Michael Faraday, it has been widely accepted that thin water layers, called quasi-liquid layers (QLLs), homogeneously and completely wet ice surfaces. Contrary to this conventional wisdom, here we both theoretically and experimentally demonstrate that QLLs have more than two wetting states and that there is a first-order wetting transition between them. Furthermore, we find that QLLs are born not only under supersaturated conditions, as recently reported, but also at undersaturation, but QLLs are absent at equilibrium. This means that QLLs are a metastable transient state formed through vapor growth and sublimation of ice, casting a serious doubt on the conventional understanding presupposing the spontaneous formation of QLLs in ice–vapor equilibrium. We propose a simple but general physical model that consistently explains these aspects of surface melting and QLLs. Our model shows that a unique interfacial potential solely controls both the wetting and thermodynamic behavior of QLLs.
- Published
- 2016
26. Liquid–liquid transition without macroscopic phase separation in a water–glycerol mixture
- Author
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Hajime Tanaka and Ken-ichiro Murata
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Aqueous solution ,Materials science ,Hydrogen bond ,Spinodal decomposition ,Mechanical Engineering ,Nucleation ,Thermodynamics ,General Chemistry ,Condensed Matter Physics ,law.invention ,Physics::Fluid Dynamics ,Condensed Matter::Soft Condensed Matter ,Fragility ,Mechanics of Materials ,law ,Metastability ,General Materials Science ,Crystallization ,Glass transition - Abstract
The existence of more than two liquid states in a single-component substance and the ensuing liquid-liquid transitions (LLTs) has attracted considerable attention because of its counterintuitive nature and its importance in the fundamental understanding of the liquid state. Here we report direct experimental evidence for a genuine (isocompositional) LLT without macroscopic phase separation in an aqueous solution of glycerol. We show that liquid I transforms into liquid II by way of two types of kinetics: nucleation and growth, and spinodal decomposition. Although liquid II is metastable against crystallization, we could access both its static and dynamical properties experimentally. We find that liquids I and II differ in density, refractive index, structure, hydrogen bonding state, glass transition temperature and fragility, and that the transition between the two liquids is mainly driven by the local structuring of water rather than of glycerol, suggesting a link to a plausible LLT in pure water.
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- 2012
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27. In situ Determination of Surface Tension-to-Shear Viscosity Ratio for Quasiliquid Layers on Ice Crystal Surfaces
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Gen Sazaki, Ken-ichiro Murata, Ken Nagashima, Harutoshi Asakawa, and Yoshinori Furukawa
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Materials science ,Ice crystals ,General Physics and Astronomy ,Nanotechnology ,Characteristic velocity ,law.invention ,Surface tension ,Viscosity ,Optical microscope ,Chemical physics ,law ,Relaxation (physics) ,Nanometre ,Wetting ,Physics::Atmospheric and Oceanic Physics - Abstract
We have experimentally determined the surface tension-to-shear viscosity ratio (the so-called characteristic velocity) of quasiliquid layers (QLLs) on ice crystal surfaces from their wetting dynamics. Using an advanced optical microscope, whose resolution reaches the molecular level in the height direction, we directly observed the coalescent process of QLLs and followed the relaxation modes of their contact lines. The relaxation dynamics is known to be governed by the characteristic velocity, which allows us to access the physical properties of QLLs in a noninvasive way. Here we quantitatively demonstrate that QLLs, when completely wetting ices, have a thickness of 9 +/- 3 nm and an approximately 200 times lower characteristic velocity than bulk water, whereas QLLs, when partially wetting ices, have a velocity that is 20 times lower than the bulk. This indicates that ice crystal surfaces significantly affect the physical properties of QLLs localized near the surfaces at a nanometer scale.
- Published
- 2015
28. Novel kinetic trapping in charged colloidal clusters due to self-induced surface charge organization
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Christian L. Klix, Alex Malins, Hajime Tanaka, Stephen R. Williams, Ken-ichiro Murata, and C. Patrick Royall
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Physics ,Multidisciplinary ,Yield (engineering) ,Isotropy ,Electrostatics ,Article ,Symmetry (physics) ,Condensed Matter::Soft Condensed Matter ,Pentagonal bipyramidal molecular geometry ,Chemical physics ,Metastability ,Cluster (physics) ,ddc:530 ,Surface charge - Abstract
Colloidal clusters are an unusual state of matter where tunable interactions enable a sufficient reduction in their degrees of freedom that their energy landscapes can become tractable — they form a playground for statistical mechanics and promise unprecedented control of structure on the submicron lengthscale. We study colloidal clusters in a system where a short-ranged polymer-induced attraction drives clustering, while a weak, long-ranged electrostatic repulsion prevents extensive aggregation. We compare experimental yields of cluster structures with theory which assumes simple addition of competing isotropic interactions between the colloids. Here we show that for clusters of size 4 ≤ m ≤ 7, the yield of minimum energy clusters is much less than expected. We attribute this to an anisotropic self-organized surface charge distribution which leads to unexpected kinetic trapping. We introduce a model for the coupling between counterions and binding sites on the colloid surface with which we interpret our findings. published
- Published
- 2013
29. Experimental indication for liquid-liquid transition in aqueous solutions
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Ken-ichiro Murata and Hajime Tanaka
- Subjects
Type transformation ,Aqueous solution ,Liquid state ,Chemistry ,Chemical physics ,Single component ,Liquid liquid ,Nanotechnology ,Anomaly (physics) ,First order - Abstract
Contrary to the conventional wisdom that there exists only one unique liquid state for any material, there are growing experimental and numerical evidence for the existence of more than two liquid states in a single component substance. The transition between them is called liquid-liquid transition (LLT). LLT has attracted considerable attention because of its counterintuitive nature and its importance in the fundamental understanding of the liquid state. However, the physical nature of the transition has remained elusive. Particularly for water, the possible existence of LLT has special implications not only on its fundamental understanding, but also on a link of various thermodynamic and transport anomalies with critical anomaly associated with LLT. In this paper, we show experimental indications for a LLT in aqueous solutions of glycerol. We demonstrated that LLT proceeds through two types of kinetics characteristic of the first order transition: nucleation-growth (NG) and spinodal-decomposition (SD) type transformation. We also reveal that local tetrahedral ordering of water molecules play a key role, which is suggestive of the presence of LLT in pure water.
- Published
- 2013
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30. Surface-wetting effects on the liquid–liquid transition of a single-component molecular liquid
- Author
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Ken-ichiro Murata and Hajime Tanaka
- Subjects
Surface (mathematics) ,Spinodal ,Phosphites ,Multidisciplinary ,Materials science ,Surface Properties ,Hydrogen bond ,Kinetics ,Temperature ,Triphenyl phosphite ,General Physics and Astronomy ,General Chemistry ,London dispersion force ,Article ,General Biochemistry, Genetics and Molecular Biology ,Liquid Crystals ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Liquid crystal ,Wettability ,Wetting - Abstract
Even a single-component liquid may have more than two liquid states. The transition between them is called a 'liquid–liquid transition' (LLT). Such LLTs have recently attracted considerable attention mainly because of the fundamental interest in the physical origin of this counter-intuitive phenomenon. In this study, we report the first observation of wetting effects on LLT for a molecular liquid, triphenyl phosphite. We find a transition from partial to complete wetting for nucleation-growth-type LLT when approaching the spinodal temperature of LLT. Some features unique to LLT are also revealed, reflecting for example the non-conserved nature of its order parameter. We also find that the wetting behaviour is not induced by dispersion forces, but by weak hydrogen bonding to a solid substrate, implying its important role in the LLT itself. Using wetting effects may open a new possibility to control kinetics and spatial patterns of nucleation-growth-type LLT., A phase transition between two liquid states is a counterintuitive phenomenon, but one that is known to happen in certain materials. Murata and Tanaka now show in tryphenyl phosphite that this can also produce a change in the wetting of a surface, from partial to complete, at the transition temperature.
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- 2010
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31. HIVgp41の構成ペプチドおよびその類似合成ペプチドによるヒト末梢血NK活性の抑制機構
- Author
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Masami Watanabe, Michito Ichimaru, Ken-Ichiro Murata, Tai-Ichiro Moriya, Hideyo Itakura, Shuichi Ikeda, and Tatsuo Kiyohara
- Subjects
Cytolysis ,Interleukin 21 ,Lymphokine-activated killer cell ,medicine.anatomical_structure ,Cell ,Immunology ,medicine ,Cytotoxic T cell ,Biology ,Cytotoxicity ,Molecular biology ,Natural killer cell ,K562 cells - Abstract
AIDS患者末梢血NK活性が抑制されている事が知られているが,このNK活性の抑制機構を解析した。無症候性キャリアのNK活性は抑制を受けておらず,その時のキャリアの末梢血のCD4+細胞は0%であった。つぎに, HIVの外殻糖蛋白質gp41の一部で,レトロウイルスに保存されている17個のアミノ酸から成るペプチドと,その類似構造をしたペプチドを3種合成した。これらの合成ペプチドは,正常コントロールのNK活性も,無症候性キャリアのNK活性も共に抑制したが,キャリアに対する抑制が著しかった。正常コントロールNK活性に対する合成ペプチドの作用段階は, NK細胞と標的癌細胞の結合にも,標的細胞によるNK細胞のTriggeringにも合成ペプチドが影響を与えないことから, Triggering以後の段階であると考えられた。一般には, AIDSの発症には,HIVがCD4+細胞に感染し,その機能が損われる事が重要だと考えられており,多くの研究が為されているが,以上の結果より,無症候性キャリアが発症するに至るプロセスには,それ以外のNK等の免疫機能の抑制が何らかの役割を果たしていると考えられた。, Three kinds of peptides termed ABJ917, ABJ918 and ABJ919 were synthesized and tested their capability of inhibition of Natural Killer (NK) cell mediated cytotoxicity. ABJ917, which is conserved among various retroviral transmembrane envelope proteins inhibited NK activities of the peripheral blood Iymphocytes (PBLs) of both asymptomatic carriers and normal controls. ABJ918 or ABJ919 which correspond to this conserved region also inhibited NK activities. To know the mechanism of inhibition of NK cells by these synthetic peptides, conjugate formation assay and triggering assays were then performed. ABJ917 which inhibited overall NK cytotoxicity did inhibit neither NK and target tumor cell binding nor NK cell triggering by target K562 tumor cells. These results show that the inhibition of NK cytotoxic activity by synthetic HIV peptide is caused in the stage of post-triggering. Peripheral blood CD4+ cell rate of the asymptomatic carriers of HIV was almost 0% when we obtained enough NK activities and these carriers were still quite healthy. Taken together, the immunosuppression of AIDS patients is thought to be caused at least partly from some defects of post-triggering lytic activity of NK cells by HIV transmembrane peptides., 日本熱帯医学会雑誌, vol.19(1), pp.33-38; 1991
- Published
- 1991
32. Control of fluidity and miscibility of a binary liquid mixture by the liquid-liquid transition
- Author
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Rei Kurita, Ken-ichiro Murata, and Hajime Tanaka
- Subjects
Materials science ,Mechanical Engineering ,Triphenyl phosphite ,General Chemistry ,Condensed Matter Physics ,Toluene ,Chemical reaction ,Miscibility ,Amorphous solid ,chemistry.chemical_compound ,Aniline ,chemistry ,Chemical engineering ,Mechanics of Materials ,Phase (matter) ,Organic chemistry ,General Materials Science ,Diethyl ether - Abstract
Matter in its liquid state is convenient for processing and controlling chemical reactions, owing to its fluidity. Recently much evidence has been accumulated for the existence of a liquid–liquid transition (LLT) in single-component liquids. Here, we report that we can control, by the LLT of a molecular liquid, triphenyl phosphite (TPP), the fluidity and miscibility of its mixture with another molecular liquid. For a mixture of TPP with toluene or aniline, we find that both liquid I and II mix well and liquid II remains in a ‘liquid’ state, in contrast to pure TPP, where liquid II is a non-ergodic amorphous state. This is the first example of a ‘true’ LLT in a molecular liquid. Furthermore, we find demixing induced by the LLT for a mixture of TPP with diethyl ether or ethanol. These findings will open a new phase of research towards various applications of the LLT. Recent work has provided evidence for the existence of a liquid–liquid transition (LLT) in some single-component fluids. It is now shown that the LLT can be used to control the fluidity and miscibility of triphenyl phosphite with another molecular liquid, demonstrating the possibility of the first definite application for exploiting this phenomenon.
- Published
- 2008
33. Kinetics and Control of Liquid-Liquid Transition
- Author
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Hajime Tanaka, Rei Kurita, Ken-ichiro Murata, Michio Tokuyama, Irwin Oppenheim, and Hideya Nishiyama
- Subjects
Physics::Fluid Dynamics ,Condensed Matter::Soft Condensed Matter ,Fragility ,Liquid state ,Chemistry ,Transition (fiction) ,Polyamorphism ,Kinetics ,Liquid liquid ,Thermodynamics ,Glass transition - Abstract
Recently it was revealed that even a single‐component liquid can have more than two liquid states. The transition between these liquid states is called “liquid‐liquid transition”. This phenomenon has attracted a considerable attention because of its counter‐intuitive character and the fundamental importance for our understanding of the liquid state of matter. The connection between the liquid‐liquid transition and polyamorphism is also an interesting issue. In many cases, liquid‐liquid transitions exist in a region which is difficult to access experimentally. Because of this experimental difficulty, the physical nature and kinetics of the transition remains elusive. However, a recent finding of liquid‐liquid transition in molecular liquids opens up a possibility to study the kinetics in detail. Here we report the first detailed comparison between experiments and a phenomenological theory for the liquid‐liquid transition of a molecular liquid, triphenyl phosphite. Both nucleation‐growth‐type and spinodal‐decomposition‐type liquid‐liquid transformation are remarkably well reproduced by a two‐order‐parameter model of liquid that regards the liquid‐liquid transition as the cooperative formation of locally favored structures. This may shed new light on the nature and the dynamics of the liquid‐liquid transition. We also show evidence that this second order parameter controls the fragility of the liquid. We also discuss a possibility of controlling liquid‐liquid transition by spatial confinement. Remaining open questions on the nature of the transition are also discussed.
- Published
- 2008
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34. Dynamic Nature of the Liquid-Liquid Transition of Triphenyl Phosphite Studied by Simultaneous Measurements of Dielectric and Morphological Evolution
- Author
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Ken-ichiro Murata, Rei Kurita, Hajime Tanaka, Michio Tokuyama, Irwin Oppenheim, and Hideya Nishiyama
- Subjects
Permittivity ,Materials science ,Static dielectric constant ,Analytical chemistry ,Triphenyl phosphite ,Physics::Optics ,Dielectric ,Structural evolution ,Physics::Fluid Dynamics ,Condensed Matter::Soft Condensed Matter ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Liquid liquid ,Spectroscopy ,Glass transition - Abstract
We performed broadband dielectric measurements for the process of liquid‐liquid transformation in triphenyl phosphite (TPP). According to our dielectric measurements, the static dielectric constant monotonically decreases and the distribution of the relaxation time becomes broader during the liquid‐liquid transformation from liquid I to II. The direct comparison with morphological evolution provides key information on the dynamical and structural evolution during LLT.
- Published
- 2008
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35. Broadband complex permittivity measurement techniques of materials with thin configuration at microwave frequencies
- Author
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Akio Hanawa, Ryusuke Nozaki, and Ken-ichiro Murata
- Subjects
Permittivity ,Materials science ,Wave propagation ,business.industry ,Analytical chemistry ,General Physics and Astronomy ,Relative permittivity ,Test method ,Fixture ,law.invention ,Capacitor ,law ,Optoelectronics ,business ,Microwave ,High-κ dielectric - Abstract
A test method to evaluate the complex permittivity of materials with thin configuration (thickness of 50–300μm) is presented. We evaluate the complex permittivity of materials with various mechanical and electrical characteristics (films, powders, and liquids) at frequencies from 100 MHz to 20 GHz and at temperatures from 293 to 353 K using an experimental method presented in this paper. We have developed a fixture having a circular parallel-plate capacitor which is suitable for the measurement of materials with thin configuration. Our method is based on theoretical consideration of wave propagation in the capacitor, which is associated with multiple reflections along the diameter of the sample. The consideration of time delay in the sample section makes it possible to evaluate the permittivity of high dielectric constant materials in the frequency range up to 20 GHz. In addition, some examples for the measurements show that the resolution with tanδ is as low as 0.001. Our method is powerful to understand...
- Published
- 2005
- Full Text
- View/download PDF
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