Papers by Katsuo Tsukamoto
First Direct Observation of Impurity Effects on the Growth Rate of Tetragonal Lysozyme Crystals under Microgravity as Measured by Interferometry
Crystal Growth & Design, Sep 9, 2015
The normal growth rates R and apparent step velocities (lateral growth rates of a spiral hillock)... more The normal growth rates R and apparent step velocities (lateral growth rates of a spiral hillock) V of tetragonal hen egg-white lysozyme (HEWL) crystals were for the first time measured by Michelson interferometry in the international space station (as part of the NanoStep project) using commercialized HEWL samples containing 1.5% impurities. A significant increase in V under microgravity was confirmed compared to step velocities Vstep on the ground, while a decrease in R was also confirmed compared to that in the purified solution under microgravity as expected. Because of exact measurement of growth rates, kinetic analyses of R were conducted as a function of supersaturation, σ (σ ≡ ln(C/Ce), where C is the concentration; Ce is the solubility), using a spiral growth model and a two-dimensional (2D) nucleation growth model. For both models over a wide range of σ, R in the impure solution was significantly lower than that in the purified solution. The degree of the suppression of impurity effects was also...
In situ observation of crystal growth from solution
Faraday Discussions, 1993
... There have been several observations that bubbles at the surface act as centres of growth for... more ... There have been several observations that bubbles at the surface act as centres of growth forhillocks, although the mechanism has not been clarified. ... This was analysed using the Abel transformation to reconstruct the quasi-three-dimensional concentration. In Fig. ...
Cosmic dust, which is composed of nanometer-sized particles and is ubiquitously distributed in th... more Cosmic dust, which is composed of nanometer-sized particles and is ubiquitously distributed in the universe, is formed in a gas outflow from evolved stars under a microgravity environment. Its formation processes have been studied on the basis of knowledge obtained under the 1 G environment on Earth and is thus not fully understood under realistic conditions. To better understand the process, here, we performed nucleation experiments of dust analogs under a microgravity environment. We show the details of our experiments using an aircraft including results of insitu observation employing an interferometer and ex-situ transmission electron microscopy to reveal the difficulty of nucleation and variability of nucleation processes. Of particular note is the size distribution of the produced particle, which was monotonical in microgravity experiments against a double peak for particles produced in the laboratory. Under a microgravity environment, nucleation tends to suppress because of s...
Japan Geoscience Union, 2014
Nucleation theories have been used to understand the condensation sequence, number density and si... more Nucleation theories have been used to understand the condensation sequence, number density and size of cosmic dust in a gas outflow of dying stars or a gas plume after shock wave heating in the primitive solar nebula. However, it has been well known that nucleation rates obtained by nucleation theories and by experiments have a large difference. We believe that the reason is uncertainties of the physical parameters of nanometer sized particles. Therefore, it is still not successful to explain the characters of cosmic dust by a nucleation theory. To determine the physical parameters of nanoparticles and evaluate nucleation theories, we constructed an in-situ observation system of temperature and concentration during homogeneous nucleation in vapor phase using interferometry for both of ground based and microgravity experiments. Nanoparticles are formed from a supercooled vapor after evaporation by electrical heating in a controlled gas atmosphere. Using the new system in lab, we succ...
Transactions of the Materials Research Society of Japan, 2008
Ettringite crystals grown by combining calcium hydroxide and aluminum sulfate solutions including... more Ettringite crystals grown by combining calcium hydroxide and aluminum sulfate solutions including some admixtures have been observed using the microscope with high magnifications up to 3000 degrees. The nucleation, growth rate and morphology of ettringite were investigated to clear the effect of admixtures on these crystal growth.
Crystals, 2019
In situ observation of the nucleation and growth of glucose isomerase (GI) crystals under microgr... more In situ observation of the nucleation and growth of glucose isomerase (GI) crystals under microgravity was conducted using an optical microscope during the first flight of the Advanced Nano Step project undertaken in the International Space Station (ISS). Very low apparent nucleation rates (J’) of GI crystals in the solution and on the substrate of the growth container were confirmed compared with those on the ground. In particular, J’ of GI crystals in the solution were a few times lower than that on the substrate. The growth rates (R) of the {101} faces of GI crystals on the substrate and the apparent growth rates (R’) in the solution were measured. The very low nucleation rates allowed us to successfully measure R at a very high supersaturation region (up to ln(C/Ce) = 6), at which R cannot be measured on the ground.
Proceedings of the National Academy of Sciences of the United States of America, Feb 28, 2017
Nucleation, the primary step in crystallization, dictates the number of crystals, the distributio... more Nucleation, the primary step in crystallization, dictates the number of crystals, the distribution of their sizes, the polymorph selection, and other crucial properties of the crystal population. We used time-resolved liquid-cell transmission electron microscopy (TEM) to perform an in situ examination of the nucleation of lysozyme crystals. Our TEM images revealed that mesoscopic clusters, which are similar to those previously assumed to consist of a dense liquid and serve as nucleation precursors, are actually amorphous solid particles (ASPs) and act only as heterogeneous nucleation sites. Crystalline phases never form inside them. We demonstrate that a crystal appears within a noncrystalline particle assembling lysozyme on an ASP or a container wall, highlighting the role of heterogeneous nucleation. These findings represent a significant departure from the existing formulation of the two-step nucleation mechanism while reaffirming the role of noncrystalline particles. The insight...
Crystal Growth & Design, 2014
Interferometric observation was attempted to the gas evaporation method to investigate the homoge... more Interferometric observation was attempted to the gas evaporation method to investigate the homogeneous nucleation and growth process of nanoparticles in vapor phase. For the first step, temperature distribution around evaporation source was measured with respect to the source temperature in the gas evaporation method for the first time in a quarter century. We visualized a condensation of smoke particles in gas phase and temperature history including a cooling rate of produced particles after nucleation was recognized. Homogeneously condensed WO_3 nuclei initially maintain their temperature for ~5 ms and then cool down with a rate of ~5×10^4 K/s. The degree of supersaturation during the nucleation was at least as high as 10^7.
Epitaxial thin film growth by vapor deposition or molecular beam epitaxy under ultra-high vacuum ... more Epitaxial thin film growth by vapor deposition or molecular beam epitaxy under ultra-high vacuum conditions generally occurs in two stages: (i) nucleation and growth of well-separated islands on the substrate; (ii) subsequent formation of a thicker continuous film with possible kinetic roughening. For homoepitaxial growth, two-dimensional (2D) monolayer islands are formed during submonolayer deposition. Typically, the presence of a step-edge barrier inhibits downward transport and leads to the formation of mounds (multilayer stacks of 2D islands) during multilayer growth. For heteroepitaxial growth, islands formed in the initial stages of deposition sometimes have a 2D monolayer structure. However, they may instead exhibit bilayer or 3D multilayer structure due to, e.g., a high film surface energy, strain, or quantum size effects. Various growth modes are possible for thicker films. Atomistic modeling provides the most detailed picture of film growth. For coherent (defect-free) epitaxial films, lattice-gas modeling analyzed by kinetic Monte Carlo simulation (KMC) is particularly successful in describing film growth on the appropriate time and length scales. For large islands or complex systems, another effective and instructive approach is laterally coarse-grained step-dynamics modeling which tracks only the evolution of step edges in each layer. However, fully coarse-grained 3D continuum modeling for the evolution of a film height function does not yet have predictive capability. Examples are provided for: Ag homoepitaxy on (100), ( ) and (110) surfaces; Ag heteroepitaxy on lattice-matched substrates including NiAl(110), NiAl(100), and Fe(100); and Ag heteroepitaxy on 5-fold icosohedral Al-Pd-Mn and 2-fold decagonal Al-Cu-Co quasicrystalline surfaces.
Physical Mechanisms of Crystal Growth Modification by Biomolecules
AIP Conference Proceedings, 2010
During the process of biomineralization, living organisms use macromolecules to direct the nuclea... more During the process of biomineralization, living organisms use macromolecules to direct the nucleation and growth of a variety of inorganic materials. Because biomineral structures exhibit complex topologies, hierarchical design, and unique materials properties, an understanding of the underlying mechanisms of biomolecular controls over mineral growth presents an opportunity to develop new strategies towards synthesis of novel materials for applications across a wide range of technologies. Herein the results from a combination of in situ atomic force microscopy (AFM) and molecular modeling (MM) studies to investigate the effect of specific interactions between carboxylate-rich biomolecules and atomic steps on calcium carbonate and calcium oxalate crystal surfaces during the growth are reviewed. The results show how the stereochemical relationships between additive and atomic step leads to modifications of crystal shape. In some cases, the inhibitory effects of strong binders are well-explained by a model of growth inhibition based on the classic Cabrera-Vermilyea theory, but updated to take into account the particular nature of biomolecular adsorption dynamics. The consequences include a positive feedback between peptide adsorption and step inhibition that results in bistable growth with rapid switching from fast to near-zero growth rates for very small changes in supersaturation. The phenomenon of biomolecule-induced growth acceleration is also reviewed and shown to be common to both the oxalate and carbonate systems. The source of acceleration is related to the activation barrier for solute attachment to steps. Finally, experimental and theoretical results are presented that suggest most biomineral phases can not be described by conventional models in which kink formation due to thermal fluctuations at step edges is rapid enough to ensure the availability of kinks. Instead, growth is kink-limited. As a consequence, biomolecule-step interactions cannot be interpreted with traditional thermodynamic models based on minimization of the Gibbs free energy. Instead these interactions follow a different mechanism determined by the kinetics of attachment and detachment. The general nature of these findings support the plausibility of their application to industrial systems.
AIP Conference Proceedings, 2010
Solution crystallization is an essential part of processes in the chemical and pharmaceutical ind... more Solution crystallization is an essential part of processes in the chemical and pharmaceutical industries and a major step in physiological and pathological phenomena. Crystallization starts with nucleation and control of nucleation is crucial for the control of the number, size, perfection, polymorphism and other characteristics of the crystalline materials. * 2 G Δ -for a formation of a crystalline nucleus inside the dense liquid.
Meteoritics & Planetary Science, 2011
In Situ Live Observation of Nucleation and Dissolution of Sodium Chlorate Nanoparticles by Transmission Electron Microscopy
Journal of the American Chemical Society, 2014
The formation of crystals from solution requires the initial self-assembly of units of matter int... more The formation of crystals from solution requires the initial self-assembly of units of matter into stable periodic structures reaching a critical size. The early stages of this process , called nucleation, are very difficult to visualize. Here we describe a novel method that allows real time observation of the dynamics of nucleation and dissolution of sodium chlorate clusters in an ionic liquid solution using in situ transmission electron microscopy. Using ionic liquids as solvent circumvents the problem of evaporation and charging, while the nucleation frequency was reduced by using saturated solutions. We observe simultaneous formation and dissolution of prenucleation clusters, suggesting that high-density fluctuations leading to solid cluster formation exist even under equilibrium conditions. In situ electron diffraction patterns reveal the simultaneous formation of crystalline nuclei of two polymorphic structures, the stable cubic phase and the metastable monoclinic phase, during the earliest stages of nucleation. These results demonstrate that molecules in solution can form clusters of different polymorphic phases independently of their respective solubility.
Morphological evolution of precipitates during transformation of amorphous calcium phosphate into octacalcium phosphate in relation to role of intermediate phase
Journal of Crystal Growth, 2011
... Selected-area electron diffraction (SAED) patterns for characterization were also used. ... V... more ... Selected-area electron diffraction (SAED) patterns for characterization were also used. ... View Within Article. The SAED pattern for the particles had a halo region around the core and a faint broad ring around the halo region (Fig. ...
Two-step nucleation process of silicate interplanetary dust particles at the vicinity of silicate melt
Journal of Crystal Growth, 2005
ABSTRACT
The reduction and recovery of step velocity in crystal growth induced by convection variation under various gravities
Journal of Crystal Growth, 2005
It is demonstrated from the parabolic flight experiments on crystal growth from solution, that a ... more It is demonstrated from the parabolic flight experiments on crystal growth from solution, that a short time disturbance of the crystal growth condition significantly influences the crystal growth kinetics via variation of the mass transport condition by directly observing the movement of spiral steps in situ. An obvious reduction of step velocity was observed in short microgravity periods of less than 20s, and the step advancing rate recovered quickly under normal gravity. The suppression of impurity adsorption at the growth steps could also be detected in such a short microgravity time by measuring the recovery process of growth steps. It is also shown from the experimental results that the regular change of gravity condition will reduce the time-dependent impurity effect on crystal growth by, probably, variation of the mass transport property.
Reproduction of chondrules from levitated, hypercooled melts
Journal of Crystal Growth, 2006
ABSTRACT
Interferometric in-situ observation during nucleation and growth of WO3 nanocrystals in vapor phase
Journal of Crystal Growth, 2011
ABSTRACT To investigate the homogeneous nucleation and growth process of nanoparticles in vapor p... more ABSTRACT To investigate the homogeneous nucleation and growth process of nanoparticles in vapor phase, interferometric observation was attempted for the first time to the gas evaporation method, which has been a commonly accepted physical production method of nanoparticles. Tungsten oxide was evaporated by electrical heating of a tungsten wire in a mixture gas of Ar and O2. WO3 nanoparticles were formed via homogeneous nucleation and growth during a gas cools following a thermal convection produced by the evaporation source. The degree of supersaturation for nucleation was extremely high, 6.6×106, which was determined from the interferogram. Surface free energy of WO3 at 1100K was calculated based on the classical nucleation theory and was 1.38×103ergcm−2, which is within the reported values. A part of the difference between actual formation rate of produced nanoparticles, which were determined based on a transmission electron microscope, and calculated values based on the classical nucleation theory were well explained if we adopt the idea of coalescence growth.
In-Situ Observation of High Temperature Silicate Solutions
Journal of Crystal Growth, 1990
id="ab1"An in-situ observation method of growth or dissolution of crystals at high temp... more id="ab1"An in-situ observation method of growth or dissolution of crystals at high temperatures is briefly explained. As examples of the application of the method, metastable nucleation phenomena observed in silicate systems, and the effect of Cr upon nucleation behavior are analyzed. It was demonstrated that the interfacial energy term has the definitive effect upon nucleation behavior.
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Papers by Katsuo Tsukamoto