A design of a bio-inspired signal/information processing device and the fabrication of a stochastic delay-derivative element (SDDE) using an immiscible polymer binary mixture of poly(L-lactic acid) with poly(ε-caprolactone) are described. A functi...
Stochastic threshold devices using a trap-filling transition (TFT) coupled with molecular dynamics in poly(3-alkylthiophene)s were fabricated as potential key devices for noise-driven bioinspired sensors and information processors. This article de...
Proceedings of SPIE - The International Society for Optical Engineering 9055 Jan 2014
Stochastic threshold devices using trap-filling transition coupled with molecular dynamics in poly(3-alkyl thiophene)s [P3ATs] were fabricated as potential key devices for noise-driven bio-inspired sensors and information processors. This article ...
Naoki Asakawa, Ken Motokura, Tatsuaki Yashima, To Ru Koyama, Toshinori O-Nuki, Akimitsu Miyaji, Toshihide Baba
Journal of Physical Chemistry C 116 17734-17738 Aug 2012
Proton-exchanged Y zeolite (H-Y zeolite) has two types of bridging hydroxyl groups; one exists in the supercage and the other exists in the sodalitecage. The dynamic property of protons due to these hydroxyl groups was investigated by variable tem...
Two applications of quasi-static magnetic field gradients in nuclear magnetic resonance spectroscopy are discussed. The first application is conformon transport in the quasi-ordered -conjugated polymer, poly(4-methylthiazole-2,5-diyl). With the as...
Hajime Munakata, To Ru Koyama, Tatsuaki Yashima, Naoki Asakawa, Toshinori O-Nuki, Ken Motokura, Akimitsu Miyaji, Toshihide Baba
Journal of Physical Chemistry C 116 14551-14560 Jul 2012
The influence of temperature on the1H chemical shift due to hydroxyl groups in H+-exchanged any kind of zeolites (ZSM-5 type zeolites including silicalite, mordenite and Y zeolites) was examined by variable temperature1H magic-angle spinning nucle...
N. Asakawa, Y. Inoue, T. Yamamoto, R. Shimizu, M. Tansho, K. Yazawa
ACS Symposium Series 1077 161-178 Jan 2011
Stochastically excitable threshold units using functional materials will potentially be among the key devices for the production of noise-driven bio-inspired sensors and information processors with ultra-low energy consumption. In particular, a no...
The molecular structure and dynamics of regioregulated poly(3- butylthiophene)(P3BT) and poly(3-hexylthiophene) (P3HT) were investigated using Fourier transfer infrared spectroscopy and high-resolution solid-state13C nuclear magnetic resonance (NM...
We demonstrated signal transmission using the nonlinearity of VO2in the manner of stochastic resonance (SR). A correlated insulator state of VO2changes nonlinearly to a metallic state when an applied bias voltage increases beyond a threshold. The ...
Koji Yazawa, Yoshio Inoue, Tadashi Shimizu, Masataka Tansho, Naoki Asakawa
Journal of Physical Chemistry B 114 1241-1248 Jan 2010
The molecular structure and dynamics of regioregulated poly(3- hexylthiophene) (P3HT) were investigated using high-resolution solid-state13C nuclear magnetic resonance (NMR) and optical absorption spectroscopies. A crystal (C)-plastic crystal (PC)...
We study effects of trehalose on the swelling behavior of hydrogel, exemplified here by agarose. Its volume increase on immersion into water is suppressed in the presence of disaeeharides, the extent of which lies in the order, sucrose < maltose <...
Kenichi Yamazaki, Tungalag Dong, Naoki Asakawa, Yoshio Inoue, Koji Yazawa
Macromolecular Rapid Communications 30 435-441 Mar 2009
A compositional graded film of poly(ε-caprolactone) (PCL) with 4,4′-thiodiphenol (TDP), in the film thickness direction, was fabricated by self-diffusing of TDP in the PCL melt. We found out the self-bending deformation of the gradient film, which...
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 79(79) 021902 Feb 2009
Problems with artificial neural networks originate from their deterministic nature and inevitable prior learnings, resulting in inadequate adaptability against unpredictable, abrupt environmental change. Here we show that a stochastically excitabl...
Materials Research Society Symposium Proceedings 1034 86-90 Dec 2008
Spinel ferrite oxides doping non-magnetic ions show the photo-induced magnetization (PIM) effect at high temperature [1-3]. Such a magnetization enhancement by light irradiation is a unique property in this material. In order effectively to use th...
Koji Yazawa, Yoshio Inoue, Takakazu Yamamoto, Naoki Asakawa
Journal of Physical Chemistry B 112 11580-11585 Sep 2008
Solid-state structures of regioregulated poly(3-hexylthiophene) (P3HT) and poly(3-butylthiophene) (P3BT) were investigated using Fourier transform infrared absorption (FT-IR) spectroscopy. This study revealed that a twist glass transition of thiop...
Applied Physics Express 1 0880021-0880023 Aug 2008
We have investigated cooperative dynamics of an artificial stochastic resonant system, which is a recurrent ring connection of neuron-like signal transducers (NSTs) based on stochastic resonance (SR), using electronic circuit experiments. The ring...
Seiichiro Mori, Takakazu Yamamoto, Naoki Asakawa, Koji Yazawa, Yoshio Inoue
Polymer Journal 40 475-478 Jul 2008
A study was conducted to determine the dynamic structure of regio-regulated head-to-head HH-P4MeTz by differential scanning calorimetry (SDC) and NMR. The study synthesized regio-regulated polyheterocylic through dehalogenative organometallic poly...
Room-temperature-photoinduced magnetization (PIM) was observed in spinel ferrite Al0.2 Ru0.8 Fe2 O4 thin films with a spin-cluster-glass structure. Additionally, the films exhibited significant properties as spintronic materials, showing a low sat...
Satoshi Koide, Naoki Asakawa, Yoshio Inoue, Koji Yazawa
Macromolecular Chemistry and Physics 209 499-507 Mar 2008
A mechanism for the generation of the compositional gradient along the long axis for poly(ε-caprolactone) (PCL)/poly(ethylene oxide) (PEO) blend under uniaxial thermal gradient was proposed by observations of the convection of polymer using graphi...
Satoshi Koide, Koji Yazawa, Naoki Asakawa, Yoshio Inoue
Journal of Materials Chemistry 17 582-590 Feb 2007
Compositionally graded bulk materials of organic polymer blends were prepared by using non-equilibrium self-organization processes with a uniaxial thermal gradient (Bridgman method). The Bridgman method was firstly applied to prepare two kinds of ...
We have developed an instrument for dynamical imaging by NMR relaxation spectroscopy. We call "dynamical imaging" a imaging method for dynamical properties such as spectrum density function of local magnetic field fluctuation or the spatio-tempora...
To analyze the heterogeneous β-sheet structure of Samia cynthia ricini silk fiber in detail, structural analysis of alanine oligomers with either parallel(P) or anti-parallel(AP) β-sheet structures was performed using solid-state NMR. The T1 value...
Koji Yazawa, Naoki Asakawa, Takakazu Yamamoto, Yoshio Inoue
Polymer Preprints, Japan 55 730 Oct 2006
The molecular structure and dynamics of regioregulated poly(3- butylthiophene)(P3BT), poly(3-hexylthiophene) (P3HT), and poly(3- dodecylthiophene) (P3DDT) were investigated by Fourier transform infrared absorption (FTIR), solid state 13C nuclear m...
We have prepared compositionally graded polymeric blend materials by using non-equilibrium self-organized processes with uniaxial thermal gradient (Bridgman method). This technique is firstly applied to prepare polymeric functionally graded materi...
Nuclear magnetic resonance(NMR) spectroscopy under inhomogeneous magnetic field is one of promising nondestructive methods for investigating transport phenomena. In the poster presentation we describe a development of an NMR dynamical imaging spec...
Koji Yazawa, Yoshio Inoue, Takakazu Yamamoto, Naoki Asakawa
Physical Review B - Condensed Matter and Materials Physics 74 Oct 2006
The molecular structure and dynamics of regioregulated poly(3- butylthiophene) (P3BT), poly(3-hexylthiophene) (P3HT), and poly(3- dodecylthiophene) (P3DDT) were investigated using Fourier-transform infrared absorption (FTIR), solid-state C13 nucle...
New five-membered ring π-conjugated polymers composed of 2,2′-bithiophene and 4,4′-dialkyl-2,2′-bithiazole units were prepared. The polymers were soluble in 1,2-dichlorobenzene and showed a UV-vis peak at about 490 nm above 120 °C. Cooling the sol...
Tomonori Honma, Li Zhao, Naoki Asakawa, Yoshio Inoue
Macromolecular Bioscience 6 241-249 Mar 2006
Poly(ε-caprolactone) (PCL)/chitin and PCL/chitosan blend films with compositional gradients were successfully fabricated by a dissolution/diffusion method; that is, repeatedly pouring the PCL/chitin (or PCL/chitosan) blend solutions, with variable...
Bo Zhu, Yong He, Naoki Asakawa, Haruo Nishida, Yoshio Inoue
Macromolecules 39 194-203 Jan 2006
The crystalline structure of biodegradable poly(3-hydroxypropionate) (PHP) has been found to quite depend on the molecular weight (MW) and crystallization conditions. In particular, a new crystal form (the δ-form) has been successfully prepared by...
Dynamics of Yamamoto-type poly(p-phenylene) [PPP] was investigated by differential scanning calorimetry(DSC) and proton solid-state NMR relaxation spectroscopy. The DSC chart shows the baseline jump without latent heat at 295K, which is due to the...
Koji Yazawa, Naoki Asakawa, Takakazu Yamamoto, Yoshio Inoue
Polymer Preprints, Japan 54 3103-3104 Dec 2005
The molecular structure and dynamics of regioregular poly(3-alkylthiophene) (P3AT) were investigated. In DSC measurements,the endothermal peak was obtained around 60°C. The FTIR spectrum also showed the peak shift from 825cm -1 and 810cm-1 to 820c...
Nuclear magnetic resonance(NMR) spectroscopy under inhomogeneous magnetic field is one of promising nondestructive methods for investigating transport phenomena. In solids the diffusion coefficient can often be small and a local internal MFG, whic...
Advanced Functional Materials 15 1630-1634 Oct 2005
A biodegradable, immiscible poly(butylenes adipate-co-butylenes terephthalate) [P(BA-co-BT)]/poly(ethylene oxide) (PEO) polymer blend film with compositional gradient in the film-thickness direction has been successfully prepared in the presence o...
Using wide-angle X-ray diffraction, high-resolution solid-state 13C NMR (SNMR), attenuated total reflection infrared (ATR/IR), and Fourier transform infrared (FTIR) spectrometry, we investigated the crystalline structure and morphology of melt-cry...
Lattice diffusion and internal local magnetic field gradients in solids are investigated by numerical simulation of nuclear mangetic resonance spin echo experiments. The Fourier-spectrum method is employed in order to solve the Bloch-Torrey equati...
A new crystal morphology (δ form) of poly(3-hydroxypropionate) (PHP) is found in cast and melt-crystallized PHPs with low molecular weight, in which the PHP chains possibly adopt a 21 helix rather than the trans conformation found in the β or γ fo...
This article describes the relationships between not only comonomer-unit compositions but also their distributions and structures as well as properties for bacterial copoly(hydroxyalkanoate)s, including poly(3hydroxybutyrate-co-3- hydroxyvalerate)...
Journal of Polymer Science, Part B: Polymer Physics 43 368-377 Feb 2005
Biodegradable poly(butylene succinate) (PBS)/poly(ethylene oxide) (PEO) polymer blend film with compositional gradient in the film thickness direction was prepared using a method of interdiffusion across the interface between the PBS and PEO layer...
Physical Review B - Condensed Matter and Materials Physics 71 Feb 2005
The dynamics of regioregulated poly(4-methylthiazole-2,5-diyl) (HH-P4MeTz) was investigated by solid-state1H,2D, and13C NMR spectroscopies, and differential scanning calorimetry (DSC) measurements. DSC,2D quadrupolar echo NMR,13C cross-polarizatio...
Journal of Applied Polymer Science 94 2466-2474 Dec 2004
The effect of lignin fine powder, as a new kind of nucleating agent, on the crystallization process of poly(3-hydroxybutyrate) (PHB) was studied. The kinetics of both isothermal and nonisothermal crystallization processes from the melt for both pu...
Journal of Polymer Science, Part B: Polymer Physics 42 2971-2982 Aug 2004
Miscibility and hydrogen bonding interaction have been investigated for the binary blends of poly(butylene adipate-co-44 mol % butylene terephthalate)[P(BA-co-BT)] with 4,4′-thiodiphenol (TDP) and polyethylene- oxide)(PEO) with TDP; and the ternar...
Bo Zhu, Yong He, Naoko Yoshie, Naoki Asakawa, Yoshio Inoue
Macromolecules 37 3257-3266 May 2004
The effect of intermolecular hydrogen bonding on the crystallization kinetics and the morphology of poly(e-caprolactone) (PCL)/4,4′- thiodiphenol (TDP) blends with TDP content 0-20 wt % has been investigated by differential scanning calorimetry, p...
Journal of Molecular Structure: THEOCHEM 675 29-35 Apr 2004
A novel method for accurate determination of small chemical shielding anisotropy (CSA) of the solid state nuclear magnetic resonance is described. The method is based on the adiabatically ramped spin-locking of transverse magnetization. The equati...
The comonomer-unit compositions and their distribution of as-produced bacterial copolyesters, including poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxy-butyrate-co-3-hydroxy propionate), poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) ...
Yang Ho Na, Yong He, Naoki Asakawa, Naoko Yoshie, Yoshio Inoue
Macromolecules 35 727-735 Jan 2002
The miscibility and phase behavior of poly(ethylene oxide) (PEO) blends with poly(3-hydroxybutyrate) (P(3HB)), poly(3-hydroxypropionate) (P(3HP)), and poly(3-hydroxybutyrate-co-3-hydroxypropionate)s (P(3HB-co-3HP)s) have been investigated by diffe...
Journal of Molecular Structure 602-603 455-461 Jan 2002
This paper describes two topics concerned with anisotropic molecular diffusion in a single crystal of stearic acid (SA) and measurements of local magnetic field gradient (MFG) in a powdered film of regio-regulated poly(4-methylthiazole-2,5-diyl)(H...
Y. Wang, S. Yamada, N. Asakawa, T. Yamane, N. Yoshie, Y. Inoue
Biomacromolecules 2 1315-1323 Dec 2001
The comonomer compositional distribution and thermal and morphological characteristics were investigated for five bacterially synthesized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] samples with 3HV content of 45, 49, 70, 80, and ...
Journal of Applied Polymer Science 82 640-649 Oct 2001
The effects of low molecular weight compounds with hydroxyl groups on the properties of poly(L-lactic acid) (PLLA) were investigated. The specific interaction between PLLA and 4,4′-thiodiphenol (TDP) was investigated by Fourier transform IR spectr...
FTIR spectra were obtained for several different states of trehalose including dihydrate crystal, anhydrous form II (designated by Gil, A. M.; Belton, P. S.; Felix V. Spectrochim. Acta 1996, A52, 1649-1659), anhydrate crystal, dried melt, amorphou...
Journal of Applied Polymer Science 81 754-761 Aug 2001
Maleinization followed by silylation of low molecular weight guayule rubber was accomplished for the first time via a two-step process. Maleinization was first effected by grafting maleic anhydride onto guayule rubber under the influence of benzoy...
Yang Ho Na, Yousuke Arai, Naoki Asakawa, Naoko Yoshie, Yoshio Inoue
Macromolecules 34 4834-4841 Jul 2001
Bacterially synthesized poly(3-hydroxybutyrate-co-3-hydroxypropionate) [P(3HB-co-3HP)] samples were compositionally fractionated using solvent/nonsolvent fractionation techniques. Binary blends between these compositionally fractionated P(3HB-co-3...
K. Ohno, N. Kamiya, N. Asakawa, Y. Inoue, M. Sakurai
Chemical Physics Letters 341 387-392 Jun 2001
We propose an integrated MOZYME+DFT method for calculation of the pKa values of ionizable residues in a protein. The method is applied to two protein systems, bacteriorhodopsin (bR) and ribonuclease T1. It is shown that the present method reproduc...
Shino Yamada, Yi Wang, Naoki Asakawa, Naoko Yoshie, Yoshio Inoue
Macromolecules 34 4659-4661 Jun 2001
The crystalline structural changes of bacterial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with narrow compositional distribution were investigated. The investigations were performed using differential scanning calorimetry (DSC) and wide-angle X...
Macromolecular Chemistry and Physics 202 1035-1043 May 2001
The formation of the inter-associated hydrogen bond between poly(ε-caprolactone (PCL) and 4,4′-thiodiphenol (TDP) was investigated as a function of composition and temperature by temperature variable Fourier transform infrared spectroscopy. It was...
The specific interactions between several low-molecular-weight diamino compounds and poly (ε-caprolactone) (PCL) have been investigated by FT-IR. It was found that PCL and 3,3′-diaminodiphenylmethane (3,3′-DADPM) interact through strong intermolec...
The miscibility of high molecular weight poly(ethylene oxide) blends with poly(3-hydroxypropionic acid) and poly(3-hydroxybutyric acid) (P(3HB)) has been investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis ...
Journal of Polymer Science, Part B: Polymer Physics 38 2891-2900 Nov 2000
The specific interaction between poly(3-hydroxybutyrate) [P(3HB)] and 4,4′-thiodiphenol (TDP) and between poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and TDP was investigated by Fourier transform infrared (FTIR) spectroscopy. Interassociat...
The solid-phase structure and biodegradability were investigated for a series of binary blends of bacterial poly(3-hydroxybutyrate) with chemosynthetic poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate-co-ε-caprolacto...
Journal of Polymer Science, Part B: Polymer Physics 38 1848-1859 Jul 2000
The effects of several low molecular weight compounds with hydroxyl groups on the physical properties of poly(ε-caprolactone) (PCL) were investigated by Fourier transform infrared (FTIR) spectroscopy and high-resolution solid-state 13C NMR. PCL an...
Journal of Physical Chemistry A 104 2716-2723 Jan 2000
Local structure of phospholipid/amine polyion complexes in lyophilized powders of dipalmitoylphosphatidic acid(DPPA)/poly-L-lysine(pLYS) and DPPA/poly-L-arginine(pARG) is investigated by solid-state nuclear magnetic resonance spectroscopy. The int...
The chromophores of rhodopsin and bacteriorhodopsin are 11-cis-and all-trans-retinal Schiff bases, respectively. Upon binding to the proteins, their unsaturated carbons show anomalous13C chemical shifts compared with those of corresponding model c...
Magnetic Resonance in Chemistry 37 303-311 Apr 1999
Analyses of13C chemical shielding tensors for powder samples of α-helix-rich poly-L-alanine (pALA) and the mechanically stretched β-sheet pALA films were performed by solid-state two-dimensional spin-echo (2DSE) NMR spectroscopy. From the iterativ...
Solid structures of the compositionally fractionated bacterial poly(3-hydroxybutyric acid-co-3-hydroxypropionic acid)s [P(3HB-co-3HP)], bearing much narrower comonomer compositional distributions, were studied by high-resolution solid-state13C n.m...
It is well known that yeast cells survive environmental stresses such as desiccation and freezing and there is evidence that these phenomena may be related to the presence of trehalose in the cells. However, the molecular mechanism by which trehal...
The conformation around the Cε - Cε′, bond of the alkyl spacer of α,ω-bis[(4,4′-cyanobiphenylyl)oxy] decane (CBA-10) was evaluated in the solid and liquid crystalline states through the detection of the dipolar interaction between Cδ and Cδ′. CBA-...
Journal of Physical Chemistry B 102 3073-3076 Apr 1998
A solid-state nuclear magnetic resonance (NMR) study for the structural elucidation of acidic phospholipid- basic polypeptide complex powder samples is presented.13C cross-polarization magic angle spinning (CP/ MAS) experiments of poly(L-lysine)/d...
Journal of the American Chemical Society 120 2047-2058 Mar 1998
Stacking of poly(3-alkylthiophene)s P3RThs and poly(4-alkylthiazole)s P4RTzs has been studied. Light scattering analysis indicates that head-to- tail (HT) type HT-P3HexTh (R = n-C6H13)gives a degree of depolarization (ρ(v)) of 0.26 in CHCl13, whic...
Journal of Molecular Structure 441 213-230 Jan 1998
It is reviewed that through the observation of solid-state13C NMR chemcial shift, the main-chain conformation and hydrogen-bonded structure of peptides and proteins in the solid state have been successfully elucidated, and the combination of solid...
While31P solid-state NMR experiments are being carried out for DPPC vesicles mixed with trehalose, the spectra exhibit sudden changes, implying that during dehydration the trehalose molecules bind to the head groups of lipids.
Two different aliphatic polyesters, bacterially synthesized polyester poly(3-hydroxybutyric acid) [P(3HB)] and chemically synthesized poly(3-hydoxypropionc acid) [P(3HP)], were blended via solvent casting. By differential scanning calorimetry, pol...
Journal of the American Chemical Society 118 8904-8915 Sep 1996
The ab initio shielding calculations are carried out to investigate the conformation dependence of13C chemical shifts for conjugated compounds like the chromophore of a visual pigment rhodopsin (Rh). First, the calculations are applied systematica...
The compositional distribution has been investigated for poly(3-hydroxybutyrate-co-3-hydroxypropionate) [P(3HB-co-3HP)]s, which were microbially synthesized by Alcaligenes latus with 3-hydroxypropionic acid, sucrose or 3-hydroxybutyric acid as the...
Macromolecular Chemistry and Physics 197 2467-2480 Jan 1996
The solid-state structure of a bacterially synthesized copolyester, poly(3-hydroxybutyrate-co-3-hydroxypropionate), P(3HB-co-3HP), with the '3HP content ranging from 0 to 37 mol-%, was analyzed by13C solid-state high-resolution NMR, X-ray diffract...
Journal of Molecular Structure 350 233-240 May 1995
13C cross polarization-magic angle spinning NMR spectra were measured for a series of peptides containing l-valine, l-leucine and l-aspartic acid residues, for which the crystal structures were already determined by X-ray diffraction, in order to ...
Journal of Molecular Structure 323 279-285 Jul 1994
The correlation between the chemical shifts and the main-chain dihedral angles of peptides containing l-alanine residues are estimated by carrying out chemical shielding calculations using the coupled Hartree-Fock method with the gauge invariant a...
Journal of Molecular Structure 317 119-129 Jan 1994
From the observation of solid-state13C NMR chemical shifts of l-alanine residues which are contained in some peptides, and the13C chemical shift calculations employing the coupled-Hartree-Fock method with gauge-invariant-atomic-orbital, it was fou...
Journal of the American Chemical Society 114 3261-3265 Apr 1992
In order to investigate the relationship between hydrogen-bond length and 13C NMR chemical shifts of L-alanine carbonyl carbons in peptides in the solid state, 13C CP-MAS NMR spectra were measured for a series of peptides containing L-alanine resi...
CP-MAS and CP-static15N NMR spectra were measured for a variety of solid oligopeptides containing the glycine residue, the crystal structures of which had already been determined by X-ray diffraction. From the results of the observed15N chemical s...
JOURNAL OF PHYSICS D-APPLIED PHYSICS 47(36) 365402 2014
Spatio-Temporal Fluctualions in Binary Mixture of Polymer Thin Films
Ryota Maruyama and Naoki Asakawa
Proceedings of The 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications and The 7th International Conference on Advanced Micro-Device Engineering 8-35 2015
Noise-driven electronic device using polymer transistors
Yoshiharu Suzuki, Teruo KANKI, Hidekazu TANAKA, and Naoki ASAKAWA
