Raman Microspectroscopy for Label-Free Diagnosis of Amyloid Light-chain Amyloidosis in Various Organs


Plasma-Assisted Annealing of Pt-Doped Rutile TiO2 Nanoparticles for Enhanced Decomposition and Bacterial Inactivation under General Lighting

Journal of Vacuum Science and Technology. B, Nanotechnology & Microelectronics : Materials, Processing, Measurement, & Phenomena : JVST B


Highly Purified Glucose Isomerase Crystals Under Microgravity Conditions Grow as Fast as Those on the Ground Do

Suppression of convection flows (solute transportation) and that of impurity incorporation into crystals seem to be the main reasons why the quality of protein crystals becomes better under microgravity conditions, whereas each precise mechanism has not been completely clarified yet. We tried to clarify the former reason by the in-situ observation of spiral growth hillocks on the {110} faces of highly purified glucose isomerase (GI) crystals under microgravity conditions and on the ground. Lateral growth rates Vlateral of a spiral hillock on the {110} face of a glucose isomerase crystal in situ under microgravity conditions and step velocities Vstep of the same configuration on the ground took similar values as far as the maximum values are compared each other. This similarity indicates there are less influences of the convection flows on the growth rates of protein crystals contrary to conventional expectations.


Basic aspects of gold nanoparticle photo-functionalization using oxides and 2D materials: Control of light confinement, heat-generation, and charge separation in nanospace

Although the optical properties of localized surface plasmon resonance and the relaxation processes of excited hot electrons in gold nanoparticles (AuNPs) have been well understood, the phenomena that occur when AuNPs relax on solid surfaces of semiconductors or insulators remain largely unknown. Thermal energy diffusion and electron transfer are relatively simple physical processes, but the phenomena they induce are interesting because of a variety of new application developments. In this Perspective, we introduce the fundamental aspects as well as advanced applications of several new physical phenomena induced by AuNPs-based hybrid materials with oxides or 2D materials. Localized heat can induce a great force on the surrounding medium to control mass transport, and plasmon-induced charge transfer reactions are expected to have applications in photocatalysis and solar cells. We also review increasing reports on the development of nano-optical sensors, transistors, and nano-light sources based on precisely controlled device structures utilizing AuNPs.


Photocatalytic Activity Enhancement of Anatase/Rutile-Mixed Phase TiO2 Nanoparticles Annealed with Low-Temperature O2 Plasma

Physica Status Solidi (A) Applications and Materials Science


Effects of Nonequilibrium Atmospheric-Pressure O2 Plasma-Assisted Annealing on Anatase TiO2 Nanoparticles


Optical Ammonia Gas Sensor with Adjustable Sensitivity Using Silicon Microring Resonator Covered with Monolayer Graphene

Japanese Journal of Applied Physics, Part 1 (Special Issues)


Steady-state and time-resolved optical properties of multilayer film of titanium dioxide sandwiched by gold nanoparticles and gold thin film

We proposed metal insulator (MI) and metal insulator metal (MIM) structures of titanium dioxide (TiO2) sandwiched by gold nanoparticles (AuNPs) layer and gold sputtered thin film (only for the MIM film) to couple localized plasmon mode of AuNP with multi reflection mode and/or cavity resonator mode of TiO2. The optical extinctions of MI and MIM with differing TiO2 thickness were studied theoretically by finite element method simulation and experimentally by optical spectrometry. The extinction peaks of MI and MIM shifted by exchanging the surrounding medium from air to TiO2. The interference of TiO2 in MI structure also affected the extinction spectra showing the oscillation along the spectrum of AuNP in TiO2. Then, the extinction degree of MIM was higher than that of MI because of the coupling between cavity resonance mode with localized plasmon mode and interband transition in AuNPs. In addition, the cross section of MI and MIM films were observed by scanning electron microscopy. The surface of thinner film was rough because TiO2 heterogeneously grew from AuNP. The irregular growth of TiO2 might have induced the wide range extinction in 300 2500 nm after Au thin film deposition. The transient absorption spectra using a femtosecond laser were also carried out under the condition of 800 nm for excitation laser and 950 nm for probe laser. The long lived electron (∼1 ns) was observed in thick MIM film as a result of hot electron transfer from the gold nanostructure in the film.

ChemNanoMat : Chemistry of Nanomaterials for Energy, Biology and More


Effects of Ultraviolet Wavelength and Intensity on AlGaN Thin Film Surfaces Irradiated Simultaneously with CF4 Plasma and Ultraviolet


Photothermal dynamics of micro-glass beads coated with gold nanoparticles in water: fine bubble generation and fluid-induced laser trapping


Photoinduced electron transfer dynamics in dye-sensitized ZnO nanowire photoanodes

International Journal of Modern Physics B


Increase of Recognizable Label Number with Optical Passive Waveguide Circuits for Recognition of Encoded 4- and 8-Bit BPSK Labels

Optical label processing is expected to reduce power consumption in label switching network nodes. Previously, we proposed passive waveguide circuits for the recognition of BPSK labels with a theoretically infinite contrast ratio. The recognizable label number was limited to four and eight for 4-bit and 8-bit BPSK labels, respectively. In this paper, we propose methods to increase the recognizable label number. The proposed circuits can recognize eight and sixteen labels of 4-bit BPSK codes with a contrast ratio of 4.00 and 2.78, respectively. As 8-bit BSPK codes, 64, 128, and 256 labels can be recognized with a contrast ratio of 4.00, 2.78, and 1.65, respectively. In recognition of all encoded labels, that is, 16 and 256 labels for 4-bit and 8-bit BPSK labels, a reference signal is employed to identify the sign of the optical output signals. The effect of phase deviation and loss along the optical waveguides of the devices is also discussed.


Improvement of Contrast Ratio in QPSK Optical Label Recognition with Passive Optical Waveguide Circuit


Microscopic Raman Study of Graphene on 4H-SiC Two-Dimensionally Enhanced by Surface Roughness and Gold Nanoparticles


Performance Analysis of All-Optical Wavelength-Shift-Free Format Conversion from QPSK to Two BPSK Tributaries Using FWM and Interference


Mechanical properties of stratum corneum in glycerin solution by atomic force microscopy

Stratum corneum (SC), the outermost skin layer, consists of corneocytes and intercellular lipids. In this study, mechanical properties of a cultured human SC and a tape-stripped human corneocyte were examined in a glycerine solution through atomic force microscopy. A multilayered cultured human SC in the low concentration glycerin solution decreased its Young's modulus with time. Besides the corneocyte increased its adhesion force in higher concentration of glycerin solution.

e-Journal of Surface Science and Nanotechnology


All-Optical Switch with Cascaded Two-Stage Mach-Zehnder Interferometers Using Saturable Absorption Accompanied by Refractive-Index Change in Graphene

IEEE/OSA Journal of Lightwave Technology


Optical Flip-Flop Operation in Orthogonal Polarization States with a Single Semiconductor Optical Amplifier and Two Feedback Loops

An optical flip-flop circuit with a single semiconductor optical amplifier (SOA) using two orthogonal polarization states is proposed. The optical set / reset input and output signals are at a single wavelength. The flip-flop circuit consists of an SOA, a polarization combiner, a polarization splitter, two directional couplers, and two phase shifters. No continuous light source is required to operate the circuit. In this paper, we theoretically analyze the operation performance. Polarization dependence in SOA is considered in the analysis at a single wavelength operation, and numerically simulated results are presented. We confirm that the flip-flop circuit with a feedback-loop length of 15 mm can be operated at switching time of around 3 ns by 1 ns set / reset pulses. The flip-flop performance is discussed from viewpoints of transient overshoot and contrast at the steady on-off states.


Recognition of 16QAM Codes by Maximum Output with Optical Waveguide Circuits, Thresholders, and Post-Processing Logic Circuit


Saturable Absorption by Vertically Inserted or Overlaid Monolayer Graphene in Optical Waveguide for All-Optical Switching Circuit


Proposal of Optical Waveguide Circuits for Recognition of Optical QAM Codes


Optical Label Routing Processing for BPSK Labels Using Complex-Valued Neural Network


Optical QPSK Label Recognition by Time-Space Conversion using Two-Dimensional Matched Filtering


All-optical switch consisting of two-stage interferometers controlled by using saturable absorption of monolayer graphene

At routing nodes in future photonic networks, pico-second switching will be a key function. We propose an all-optical switch consisting of two-stage Mach-Zehnder interferometers, whose arms contain graphene saturable absorption films. Optical amplitudes along the interferometers are controlled to perform switching between two output ports instead of phase control used in conventional switches. Since only absorption is used for realizing complete switching, insertion loss of 10.2 dB is accompanied in switching. Picosecond response can be expected because of the fast response of saturable absorption of graphene. The switching characteristics are theoretically analyzed and numerically simulated by the finite-difference beam propagation method (FD-BPM).


Joint operation of atomic force microscope and advanced laser confocal microscope for observing surface processes in a protein crystal

We demonstrated the in-situ observation of a moving atomic force microscope (AFM) cantilever using a laser confocal microscope combined with a differential interference microscope (LCM DIM). The AFM cantilever scanned or in-dented the {110} surface of a hen egg-white lysozyme crystal in a supersaturated solution. Using a soft cantilever, we could observe the step growth with high time resolution by LCM DIM and perform quantitative measurements of the step height by AFM simultaneously. In addition, a hard cantilever was used with LCM DIM to observe the dynamics of crystal surface scratching and indentation. In the supersaturated solution, the small steps generated from the scratched line aggregated to macro steps, and subsequently flattened the surface.

Journal of Surface Engineered Materials and Advanced Technology


Interference Phenomena Observed on an Atomic Force Microscope Cantilever by Laser Confocal Microscopy

We investigated interference phenomena that were observed on a cantilever bar of an atomic force microscope by using a laser confocal microscope (LCM). First, we established a simple model and calculated a fringe interval. The interference fringe patterns were observed under the following conditions (1) changing the focus and confocal aperture of LCM, (2) increasing reflectance by sputtering TiO2 on the cantilever bar and glass plate, and (3) changing the medium from air to water in the space between the glass plate and the cantilever. The purpose of a previous experiment was to measure the refractive index of water. It was theoretically determined that the fringe interval depended not on the height of the cantilever from the surface but on the wavelength, refractive index, and tilt angle of the cantilever. We obtained the following experimental results (1) the fringe interval was independent of the confocal plane when using a monochromatic laser, (2) a sharpened interference fringe was observed when we used TiO2 coated cantilever and glass plate, and (3) the refractive index of a small quantity of water could be measured.

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Effects of high pressure on the step velocity on the {110} faces of tetragonal lysozyme crystals


Passive Waveguide Device Consisting of Cascaded Asymmetric X-junction Couplers for High-Contrast Recognition of Optical BPSK Labels

IEEE/OSA Journal of Lightwave Technology


Optimization of Two-Dimensional Filter in Time-to-Space Converted Correlator for Optical BPSK Label Recognition Using Genetic Algorithms

A two-dimensional filter for photonic label recognition system using time-to-space conversion and delay compensation was designed using Genetic-Algorithms (GA). For four-bit Binary Phase Shift Keying (BPSK) labels at 160Gbit/s, contrast ratio of the output for eight different labels was improved by optimization of two-dimentional filtering. The contrast ratio of auto-correlation to cross-correlation larger than 2.16 was obtained by computer simulation. This value is 22% larger than the value of 1.77 with the previously reported system using matched filters.


Hybrid observation of crystal growth using laser confocal microscope with atomic force microscope


Wavelength Dependence of Optical Waveguide-Type Devices for Recognition of QPSK Routing Labels

In photonic label routing networks, recognition of optical labels is one of the key functions. We have proposed passive waveguide-type devices for recognition of optical labels coded in quadri-phase-shift-keying (QPSK) form. In this paper, we consider wavelength dependence of the devices. The basic module of the proposed device consists of a 3-dB directional coupler, two Y-junctions, and an asymmetric X-junction. The Y-junction and an asymmetric X-junction have basically no wavelength dependence. Although the 3-dB directional coupler has weak wavelength dependence, the device for two-symbol label recognition is found to work in wavelength 1.5-1.6µm. The performance of the device is confirmed by simulation using beam propagation method (BPM).


All-Optical Wavelength-Selective Switch Consisting of Asymmetric X-junction Couplers and Raman Amplifiers for Wide Wavelength Range


Wavelength-Insensitive Integrated-Optic Circuit Consisting of Asymmetric X-junction Couplers for Recognition of BPSK Labels


Photonic Label Recognition by Time-Space Conversion and Two-Dimensional Spatial Filtering with Delay Compensation


Waveguide-Type Optical Circuit for Recognition of Optical QPSK Coded Labels in Photonic Router


Birefringence measurements of MnPc thin film by polarization microscopy

We have studied optical properties of near-infrared (NIR) spectra and birefringence of the manganese phthalocyanine (MnPc) thin films. The morphology of the MnPc thin film grown on KCl (0 0 1) substrates was observed by using an atomic force microscope. The NIR spectral range of 1.0 1.7 μm was studied in this study, because that of 1.3 1.5 μm is known as an optical communication wavelength. The birefringence was measured with changing the growth condition of a deposition rate and a substrate temperature. The birefringence of the film was most affected by the deposition rate.


Growth of ZnS Nano-Crystallites in Gel and their Characterization

The conditions for the gel growth of ZnS were studied in this paper. The controlled reaction between theCH3CSNH2 and Zn(NO3)·6H2Osolutions by the diffusion process in a metasilicate gel was used for growing ZnS crystals. The nano-crystallites formed in the gel have been examined by electron microscopy. The following results were obtained: (1) the resulting particles with a size of 5 nm were identified to be zinc-blende ZnS particles and (2) the luminescence property of the crystals was studied by means of cathode luminescence spectroscopy.

ゲル成長法により，ZnSナノ結晶の育成を行った．結晶は，Zinc blendタイプの構造を持った5nm程度の直径のナノ結晶の集合体として析出し，カソードルミネセンスにより微弱で，短い時間ながら，280nmの波長の光を観測した．


Succession of stacking fault in hard-sphere crystal under gravity by Monte Carlo simulation

We have performed Monte Carlo simulations of hard spheres under gravity. Vertical boundaries are hard walls, which are well separated with each other. On the other hand, the periodic boundary condition is imposed in the horizontal direction. While we previously reported enhancement of crystallinity as well as crystallization due to gravity, we present here the results that demonstrate the succession of a defect. In case that the crystal formed at the bottom of the system includes kinds of stacking disorders for the (001) growth, twin band structure develops as mediated by a stacking disorder succeeded in the crystal formed in the fluid region which lies on the bottom crystal. In case that the stacking structure along horizontal direction changes from the (111) stacking to the (001) stacking, twin band structure in the (001) stacking region develops as succeeded in the crystal transformed. The twin band structure also becomes large with its upward growth.


Vapour growth and morphology of PbBr2 crystals

In this paper, the vapour transport of PbBr2 under vacuum during vacuum distillation refining and its condensation on the wall of the vessel were described. The macro- and micro morphologies of PbBr2 crystals grown in the vessel (glass tube) were studied. The crystal shape changed dramatically depending on the positions of condensation in the vessel, i.e., the crystal shape varied from an isometric polyhedron to columnar crystals with facets, and to a massive crystal without facets with a rise in the wall temperature. These results were interpreted in terms of the concentration gradient of the molecules in the vessel, surface roughening and/or surface melting of the crystals.

気相成長による{PbBr_2}結晶の育成を行った．低真空で排気しながら結晶化を行うことで，純度の低い原料からでも，光学的に透明な結晶の育成が出来るようになった．


Shrinking stacking fault through glide of the Shockley partial dislocation in hard-sphere crystal under gravity

Disappearance of a stacking fault in the hard-sphere crystal under gravity, such as reported by Zhu et al. [Nature 387 (1997) 883], has successfully been demonstrated by Monte Carlo simulations. We previously found that a less ordered (or defective) crystal formed above a bottom ordered crystal under stepwise controlled gravity [Mori et al., J. Chem. Phys. 124 (2006) 174507]. A defect in the upper defective region has been identified with a stacking fault for the (001) growth. We have looked at the shrinking of a stacking fault mediated by the motion of the Shockley partial dislocation; the Shockley partial dislocation terminating the lower end of the stacking fault glides. In addition, the presence of crystal strain, which cooperates with gravity to reduce stacking faults, has been observed.


Characteristic nanocrystallite growth of PbBr2 in a magnetic field in gel

Nanocrystallites formed with a magnetic field in gel have been examined by transmission electron microscopy. Micro-twin and multiply twinned nanoparticles of PbBr2 were selectively grown induced by the reaction under the influence of the magnetic field during the gel growth between Pb(NO3)2 and KBr solutions. The pentagonal growth in a magnetic field was discussed as a result of the attenuation of the ionic component in PbBr2 crystals.

{PbBr_2}結晶のゲル成長に及ぼす磁場効果に関する研究を行った．


Monte Carlo simulation of crystal-fluid coexistence states in the hard-sphere system under gravity with step-wise control

Monte Carlo (MC) simulations were performed for hard spheres (with diameter sigma and mass m) placed between well-separated upper and lower hard walls. A periodic boundary condition was imposed in the horizontal direction. The system was exposed to the gravitational field with the acceleration due to gravity g. After preparing a melt as the initial state, g was increased stepwise up to mgsigma/kBT([equivalent]g*)=1.5 or 2.0 with an increment Deltag*=0.1; kBT is the temperature multiplied by Boltzmann's constant. We maintained g* at each value for 2.0×105 MC cycles. The transition of the system into a metastable state such as a polycrystalline state due to trapping phenomena was successfully avoided. A monotonic increase and subsequent saturation were observed for the development of the crystalline region formed at the bottom of the system. The development of this region accompanied a shrinkage of the defective (or less ordered) crystalline region that was formed between the bottom region and the fluid phase. As the development of the bottom region almost saturated, the defective region grew upward again.


Crystal structure of hard spheres under gravity by Monte Carlo simulation

Monte Carlo simulations were performed for hard spheres (HSs) under gravity. The gravity was increased stepwise. HSs were placed between the bottom and the top hard walls. For g*R0.9, we observed that a `sediment' was comprised of two crystalline and one fluid regions. Here, g* is defined by g*Zmgs/kBT with m being the mass of a particle, s the HS diameter, g the acceleration due to gravity, and kBT the temperature multiplied by Boltzmann's constant. The bottom crystal was less defective or well-ordered and the crystal lay between the bottom one and the fluid phase was defective or less-ordered. In this paper, we investigate the structure of the crystals. Despite no apparent defects, the crystal has highly been distorted. That is, the fcc lattice has been contracted in the vertical direction more than in the horizontal direction. The crystal fluid coexistence condition for the bulk HS system does, in principle, not hold for the present systems at the crystal fluid interface. In addition, though the fine scale density profile exhibits a discontinuity apparently across the crystal crystal interface, the interlayer separation increases linearly with the height.

Science and Technology of Advanced Materials


Effects of magnetic field on the gel growth of PbBr2

Effect of a magnetic field on the gel growth of PbBr2 was studied by observing nanocrystallites in silica gel. The control of the reaction between the Pb(NO3)2 and KBr solutions by the diffusion process in a sodium metasilicate gel was used for the growth of PbBr2 crystals. The nanocrystallites formed in the gel prepared with and without the magnetic field have been examined by transmission electron microscopy. The following results were obtained. (1) Oriented PbBr2 nanocrystallites were obtained in the gel prepared with magnetic field. (2) The size of these nanocrystallites was four times larger than that of crystallites grown in the gel prepared without magnetic field (25 nm).

磁場中で合成したゲルを用いた{PbBr_2}結晶のゲル成長に関する研究を行った．磁場中で合成することにより，ナノ結晶が凝集した多結晶体が発生することを明らかにした．


Enhancement of Crystallization of Hard Spheres by Gravity: Monte Carlo Simulation

We present the effects of gravity on the growth of a hard-sphere (HS) crystal as determined by Monte Carlo simulations. HSs were confined between hard walls at the top (z . Lz) and the bottom (z . 0) of the system with a periodic boundary condition in the horizontal direction. After preparing a melt state as an initial state, the gravity was suddenly switched on. The values of the gravity were mg_=kBTd_ g_T . 0:1; 0:2; . . . ; 2:0, where m was the mass of a HS, g the acceleration of gravity, _ the HS diameter, and kBT the temperature multiplied by Boltzmann's constant. We observed the enhancement of crystallization due to gravity up to g_ . 0:7 and that the crystals of largest size were formed at g_ . 0:7{0:9. On the other hand, for g_ _ 1:0, the top position of the HS crystal that was grown from the bottom became lower with an increase in the gravity, where crystals with various axis directions coexisted. The polycrystallization is speculated to occur due to polynucleation. These results are qualitatively consistent with those of an experimental study of the centrifugal sedimentation of colloidal crystallization.

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Growth of single crystals of PbBr2 in silica gel

The conditions for the gel growth of PbBr2 were studied in this paper. The controlled reaction between the Pb(NO3)2 and KBr solutions by the diffusion process in a sodium metasilicate gel was used for growing PbBr2 crystals. The following results were obtained: (1) Transparent PbBr2 single crystals were obtained in a high-acidic gel. (2) Sizable single crystals of PbBr2 were also grown in the liquid placed over a gel because the gel barrier had the task of slowing down the diffusion rate of reacting ions.

音響光学結晶の一種として知られる臭化鉛(PbB_2)結晶の作成を試みた．結晶化方法はゲル成長法を用いた．


Growth of copper-phthalocyanine nano-crystallite epitaxially grown on KCl(001) substrate

We report the epitaxial growth of the copper-phthalocyanine (CuPc) nano-crystallite on KCl {0 0 1} substrate by a thermal treatment method. When the crystallite is nucleated from a thick CuPc film, the crystallites grow with a random orientation. However, when CuPc is grown by the crystallization cycle of the vapor deposition and the thermal treatment, the crystallites grow keeping the epitaxial relationship.


Melt Growth and Characterization of PbBr2 Single Crystals

PbBr2 single crystals were grown by a vertical Bridgman method. The objective of this work is to examine the following two: (i) how the crystal quality is influenced by purification, (ii) how the crystal quality is influenced by growth rate. The following results were obtained. (1) The crystals grown from the materials of 99.99% and 99.999% purity were not transparent if they were not purified. On the other hand, a transparent crystal was obtained even from the material of 99.99% purity when it was refined by directional freezing as well as vacuum distillation. (2) It was found that very slow growth rate was needed to grow transparent crystals.

音響光学結晶の一種として知られる臭化鉛(PbB_2)結晶の作成を試みた．結晶化方法はブリッジマン法を用い，初材料として純度の異なる試料と，さらに真空蒸留精製，帯溶融精製を行った試料を用いた．できた結晶は，光学顕微鏡および，吸光度測定を行った．最も，品質のよい結晶は，99．99%の試料をさらに，真空蒸留精製，帯溶融生成した試料で，品質のよかった結晶は大きさの点に於いても優れていた．


Flux growth of ZnS single crystals and their characterization

Cubiczincsulfide crystals were grown by a flux method using PbCl2 as a flux. The crystals were grown in the shape of platy or bulky crystals. The surface microtopographs of the crystals were observed by a differential interference microscope. One surface (top surface) of the platy crystals showed layer growth pattern that suggested the spiral growth mechanism, whereas another surface (back surface) showed the dendritic pattern. The luminescence property of the crystals was studied by means of cathode luminescence spectroscopy. Three peaks of spectra were observed at the wavelength of about 560, 470 and 336nm depending on the purity, growth shapes, and top or back faces of platy crystals. The intensity of these spectra was varied depending on the growth conditions.

透明な半導体として近年注目を集めている硫化亜鉛(ZnS)結晶のフラックス成長を試みた．塩化鉛をフラックスとし，できた結晶は微分干渉顕微鏡，および，粉末X線により結晶の評価を，カソードルミネッセンス(CL)測定により半導体としての発光に関する測定を行った．ZnS結晶はZn面とSulfar面が存在するためにできた結晶もフラットな面とラフな面の2種類観察できた．このうちラフな面のみ336nmに発光が見られた．


Growth of Cobalt-Phthalocyanine on KCl(001) Substrate and Copper-Phthalocyanine Whisker

KCl(001)面上に，蒸着ー焼鈍により成長したコバルトフタロシアニン結晶に関する研究を行った．コバルトフタロシアニンは，KCl上でウィスカー上に成長したが，銅フタロシアニンナノウィスカーと比較すると，太さが細くなり，配向性も消失した．さらに，本論文では，エピタキシャル成長した銅フタロシアニンナノウィスカーの上にコバルトフタロシアニンナノウィスカーを成長させることで，ナノオーダーの太さを持ったヘテロエピタキシャル界面の作成に成功した．


Recrystallization of Cu-phthalocyanine on KCl (0 0 1) substrates by annealing method

有機半導体の一種である銅フタロシアニンを，(001)面で劈開したKCl上で結晶化を行った．結晶化方法は，真空蒸着した後試料を焼鈍することにより行い，太さ数十nm，長さ数ミクロンのウィスカーが成長することを明らかにした．このウィスカーは，KCl<100>方向で尚かつ基板と約60°傾いた方位に配向していた．このような，有機半導体エピタキシャルウィスカーの存在は，本論文により世界で初めて明らかにされた．


Striations in the KCl single crystals grown from aqueous solutions

Growth striations were always observed on the etched surfaces of KCl crystals grown from aqueous solutions doped with Pb. However, the origin of the striations is not known in the case of aqueous solution growth. In this work, it was studied how the width and period among the striations were influenced by the growth rate and concentration of the dopant Pb. The crystals were grown from the aqueous solutions doped with Pb (1/4000 1/1250 in molar fraction) by an evaporation method at pH=2.0. The average growth rates were changed from 24 to 115 mm/day by controlling the evaporation rate. It was found that both the width and period among the striations decreased with an increase of the average growth rate. However, the effects of the concentration of dopant Pb upon the width and period among the striations were not found within the concentration range examined.

成長縞はメルト成長，溶液成長，フラックス成長においてごく普通に形成される．メルト成長においては成長縞は固液界面温度の周期的変化によって形成されると考えられている．しかし溶液成長においてはその形成メカニズムは解明されていない．本研究ではKClの水溶液成長で，成長縞の間隔に及ぼす成長速度や添加物(Pb)の効果を調べ，その結果にもとずいて形成機構を考察した．


Habit changes of NaBrO3 crystals grown from aqueous solution doped with sodium acetate

The effects of doping of sodium acetate upon the habit changes of NaBrO3 crystals have been investigated. The crystals were grown from aqueous solution under the following conditions: (i) supersaturations, ln ðC=CeÞ ¼ 020:4; (Ce: equilibrium mol fraction); (ii) growth temperatures, 15 431C. The gross morphologies of crystals have taken on three distinct forms: tetrahedral {1 1 1} habit, cubic {1 0 0} and intermediate ({1 1 1}+{1 0 0}) habits. The result of habit changes was shown in a plot of growth temperature against supersaturation as compared to the results from nondoping and doping of 1.15mol% acetic acid (J. Crystal Growth 158 (1996) 336; J. Crystal Growth 212 (2000) 507). The dependency of the growth rates upon the growth temperatures was investigated under the conditions where the supersaturation was kept constant. It was found that the growth rates of {1 0 0} were drastically reduced at higher growth temperatures.

本研究はNaBrO3の晶相変化と成長条件に関する研究である．特に注意を払ったのは，不純物添加の効果である．本研究では不純物として酢酸Naを選んだ．結果は温度を縦軸に，過飽和度を横軸にとって，形の状態図として纏めた．要約すると伊かのようである．①


Effect of a magnetic field on the growth rate of tetragonal lysozyme crystals


Effect of a magnetic field on the orientation of hen egg-white lysozyme crystals


Highly Purified Glucose Isomerase Crystals Under Microgravity Conditions Grow as Fast as Those on the Ground Do

Suppression of convection flows (solute transportation) and that of impurity incorporation into crystals seem to be the main reasons why the quality of protein crystals becomes better under microgravity conditions, whereas each precise mechanism has not been completely clarified yet. We tried to clarify the former reason by the in-situ observation of spiral growth hillocks on the {110} faces of highly purified glucose isomerase (GI) crystals under microgravity conditions and on the ground. Lateral growth rates Vlateral of a spiral hillock on the {110} face of a glucose isomerase crystal in situ under microgravity conditions and step velocities Vstep of the same configuration on the ground took similar values as far as the maximum values are compared each other. This similarity indicates there are less influences of the convection flows on the growth rates of protein crystals contrary to conventional expectations.


In-situ observation of stratum corneum using cantilever assisted two-beam interference microscopy

We demonstrated the in-situ observation of the swelling process of stratum corneum (SC) by cantilever-assisted two-beam interference microscopy (CATBIM). The CATBIM enabled us to observe the refractive index changes of a small region of stratum corneum in 1% glycerin solution. Interference pattern images of the SC were successfully acquired. The fringe interval was almost the same during the experiments. Conversely, the thickness of SC because of swelling increased with time, and the speed of swelling decreased with time.


Significant Decrease in the Solubility of Glucose Isomerase Crystals under High Pressure

グルコースイソメラーゼ結晶の溶解度を0.1, 100 MPaでその場観察により測定した．具体的にはマイケルソン干渉計を用いてある濃度の溶液が結晶と平衡状態になるための平衡温度を，溶液濃度と圧力を変えて測定した．その結果，加圧に伴い溶解度が減少した．30℃で0.1から100 MPaまで加圧すると溶解度は1/9になった．このことはVisuriらによって報告された加圧による結晶化の促進を支持する．