The suppression of protein adsorption must be required for a surface of biomaterials to avoid undesirable biological reactions. Understanding the interactions between proteins and surfaces is necessary to construct new biomaterials that have ultimate nonbiofouling property. Protein adsorption causes in an aqueous medium, therefore, we focused on the hydration state at the interface of the aqueous medium with proteins and the contacting materials, and investigated the effects of hydration state on protein adsorption behavior towards the surface. We could successfully establish the method for evaluation of dynamics of water molecules in the vicinity of the surface by using proton nuclear magnetic resonance spectroscopy for the hydrated polymer brush layer-modified micro-silica beads. The zwitterionic and cationic polymer brush surfaces were used for the measurement. The results clearly indicated that the dynamics of water molecules determined protein adsorption onto the surfaces. Thus, the polymer brush surfaces with hydration layer and high-diffusion of water molecules in the layer, such as phosphorylcholine group-bearing polymer brush surface, were effective to inhibit protein adsorption.

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PEGylated calcium phosphate nanoparticles (CaPNPs) were prepared through the simple mixing of calcium and phosphate solutions in the presence of a PEG-block-poly(4-vinylbenzylphosphonate) (PEG-b-PVBP). The PEG-b-PVBP possesses the phosphonate side chains and the hydrophobic polystyrene segment which enhance the stability of the PEG brush layer on the CaPNP surface. The size of CaPNPs was controlled within the range of several tens of nanometer depending on the [PVBP unit]/[phosphate ion] feed-molar ratio upon the CaP coprecipitation reaction. The obtained CaPNPs showed excellent colloidal stability and it was sustained even after the lyophilization. In vitro cell cytotoxicity assay suggested that the CaPNPs do not induce serious cytotoxicity in the murine colon adenocarcinoma 26 (C-26) cells. Light scattering study revealed that the CaPNPs can be dissolved into the low Ca²⁺ condition ([Ca²⁺] = 0.1 mM). Since intracellular Ca²⁺ concentration is four orders of magnitude lower than the extracellular one, the Ca²⁺ concentration responsive dissolution behavior of CaPNPs is promising for the intracellular delivery of therapeutic materials.

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  In the present study, we have designed a polymer colloid from a multi-block polymer chain composed of a hydrophobic and a hydrophilic segment. The hydrophobic segment consisted of the amorphous polymer poly(trimethylene carbonate) (PTMC) and was synthesized by ring-opening polymerization (ROP) of trimethylene carbonate. The hydroxyl terminal on the PTMC was functionalized for subsequent living radical polymerization of two functional vinyl monomers: N-isopropylacrylamide (NIPAAm) and 2-methacryloyloxyethyl phosphorylcholine (MPC), where poly-NIPAAm (PNIPAAm) shows thermo-responsive behavior, and poly-MPC (PMPC) is highly biocompatible. In this way, functional polymers were obtained via a hybrid polymer synthesis technique. The chemical structure of the resulting polymer was determined by ¹H-NMR and IR, and its solution properties were evaluated by UV spectroscopy, fluorescence spectroscopy, and dynamic light scattering (DLS). It was confirmed that the resulting polymers spontaneously self-aggregated in water by the Tyndall phenomenon, where the hydrophilic PNIPAAm and PMPC presumably covered the hydrophobic and amorphous PTMC domain. From DLS, we found that the diameter of the aggregation was changeable in terms of polymer sequence. Aggregates of the tri-block copolymer in water showed a diameter of 460 nm at 25°C, while at 35°C, the particle size decreased to 370 nm as a result of the increased hydrophobicity of the NIPAAm unit on the polymer. The polymer colloid could encapsulate a fluorescent probe proving the existence of a hydrophobic domain in the aggregate.

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Biodegradable polymers can be used in living systems. One such biodegradable polymer that has attracted considerable attention in recent years is poly(trimethylene carbonate) (PTMC). In this study, poly(ethylene glycol) monomethyl ether (mPEG), which has hydrophilic properties, was used as the initiator for PTMC synthesis. The mPEG-PTMC block copolymer exhibits amphiphilicity and forms a very stable aggregation in a solvent. In our previous study, mPEG-PTMC aggregations that remained stable for two months in a methanol solvent were prepared. In the present study, the aggregation of this polymer could be maintained in a stable state for 1 year in ultrapure water owing to the hydrophilic segment of mPEG. Additionally, examination of the encapsulation properties of the aggregation was also performed using 8-anilino-1-naphthalenesulfonic acid. Encapsulation of the aggregation caused the intensity of the fluorescence to become high and the maximum fluorescence wavelength to shift to the short wavelength resion with increasing polymer concentration. The high stability and encapsulation property of this aggregation will facilitate application of this polymer to drug delivery systems.

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  New macromonomers based on poly(trimethylene carbonate) (PTMC) were designed and synthesized under precisely controlled conditions using conventional ring-opening polymerization (ROP) techniques. We found that PTMC was connected via the hydroxyl group of N-hydroxyethyl acrylamide (HEAA) or 2-hydroxyethyl acrylate (HEA). However, the preparation of the macromonomers was strongly affected by the concentration of the organic catalyst, inducing unfavorable side reactions. Optimized ROP could be performed by adjusting the concentration of the organic catalyst, 1,8-diazabicyclo[5.4.0]undec-7-ene. The polymerization degree of HEAA-PTMC and HEA-PTMC was maintained in the range of 10 to 50. The reaction was confirmed from the results of ¹H NMR. In this study, we focused on HEAA-PTMC macromonomers. We synthesized the amphiphilic graft copolymer using HEAA and optimal synthetic conditions were proposed.

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  Poly(ether ether ketone) (PEEK) is a kind of super engineering plastics, which has good mechanical properties and heat- and chemical-resistances. We have therefore attempted to use PEEK for cardiovascular devices. The cardiovascular devices require both mechanical properties and antithrombogenicity. We modified the PEEK surface by the photoinduced graft polymerization with 2-methacryloyloxyethyl phosphorylcholine (MPC) (PMPC-grafted PEEK) for obtaining antithrombogenicity. Polymerization was carried out on PEEK surface under ultraviolet ray (UV) irradiation and we controlled monomer concentrations, temperatures and UV intensities. With increased the polymer layer thickness, the amount of fibrinogen adsorption decreased. The fibrinogen is dominant protein to determine platelet adhesion and activation. When contacted with human platelet rich plasma, PMPC-grafted PEEK surface clearly showed inhibition of platelet adhesion and activation. Thus, the PMPC-grafted PEEK is significant method to obtain antithrombogenicity.

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A three dimensional (3D) matrices for cell culture is widely used in the cell engineering field. In the living organisms, the cells react to the extra cellular matrix such as collagen. Thus, the biological interaction between the extra cellular environment and cell function is required to be elucidated in order to design an ideal environment for cell culture. In this study, cytocompatible phospholipid polymer hydrogels were prepared to encapsulate cells and the physiochemical properties of the cell-encapsulated hydrogel were investigated. The hydrogels were prepared using poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate-co-p-vinylphenylboronic acid) (PMBV). Mixture of PMBV aq. solution and poly(vinyl alcohol) (PVA) aq. solution under the biological condition spontaneously forms the PMBV/PVA hydrogels. Storage modulus of the hydrogels was tuned through adjustment of the mixing ratio of the polymer solution. An epidermal cells were encapsulated in the PMBV/PVA hydrogels during preparation process and the encapsulated cell density was controlled when the solutions were mixed. The change of the number of encapsulated cells and the storage modulus of the polymer/cell complex were measured through three days of incubation. The proliferation of the encapsulated cells was influenced by the storage modulus of the PMBV/PVA hydrogel. From this result, it was considered that the dynamical changes of the cells and their environment were evaluated through the physical properties of polymer/cell complex. The PMBV/PVA hydrogel is a promising platform for 3D cell engineering.

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Ultrathin films of regularly adsorbed biological molecules have been fabricated by means of the modified Langmuir-Blodgett (LB) method using an organo-modified alminosilicate (montmorillonite). In this combined methods, clay LB films play a template role in the formation of the lysozyme thin layer. Monolayer behavior on the buffer solution containing lysozyme molecules monitored by pressure-area isotherms. Confirmation of chemisorption of biological molecules to the anionic montmorillonite surface is performed by comparison between IR spectra of multilayers of organo-clay and one chemisorbed lysozyme. The bands of N-H and C=O stretching vibration of lysozyme were clearly confirmed on the spectra of multilayers chemisorbed biomolecules. Surface morphology of these monolayers was observed by atomic force microscopy. The difference between height information of monolayers for only organo-modified alminosilicates and their adsorbed lysozyme indicates about 9 nm. This value is almost corresponded to twice for length of lysozyme along the long axis. Hence, formation of double layered structure of biomolecule on the montmorillonite surface was assumed in this system.

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  Bone-specific drug delivery is important for the treatment of osteoporosis and osseous metastases. Bisphosphonates are currently the major drugs used in this treatment. The clinical action of bisphosphonates on bone has been clarified and the molecular structure has been improved in order to obtain higher efficiency. By mimicking the chemical structure of bisphosphonate, we have synthesized polyphosphoester ionomers to modify the surface of phospholipid vesicles as novel bone-specific drug carriers. The ring-opening copolymerization of cyclic phosphoester monomers bearing ethoxy and benzyloxy groups was performed by using cholesterol as an initiator. The deprotection of benzyl groups from the copolymers results in the production of amphiphilic polyphosphoester ionomers (CH-PHE).
  Small unilamellar vesicles (SUVs) composed of 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) vesicles mixed with CH-PHE were prepared. The ζ-potential of the vesicles was decreased by immobilization of CH-PHE; the amount was influenced by the structure and fraction of CH-PHE. The release rate of 5-carboxyfluorescein from the vesicles could be controlled by changing the fraction of DOPC and CH-PHE.

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  The LaFeO_x (LFO) powder for pulsed laser deposition (PLD) target was prepared by Pechini method. The fired temperature was optimized at 800ºC to obtain small particle with dominantly 0.8 μm in diameter without any other phases. The target surface after PLD deposition was quite smooth, resulting in the constant growth rate of 0.0671 unis/sec with 135.4 units in film thickness. The intensity of the specular spot, using high-pressure reflection high energy electron diffraction (RHEED) equipment, showed oscillation until the end of the growth, indicating the layer-by-layer growth. The LFO film surface was step-terraces structure. Around LFO Bragg diffraction, Laue oscillation was clearly observed. All obtained results revealed that the LFO film was perfect using dense target, the powder of which was prepared by Pechini method.

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  In order to develop an anode without precious metal oxides for a polymer electrolyte water electrolysis, the oxygen evolution reaction (OER) on Zr compound film and Zr compound powder have been investigated in sulfuric acid. The Zr compounds film was prepared by the reactive sputtering under various partial pressure of oxygen and temperature of base material. The Zr compound powder was prepared from ZrC_0.5N_0.5 by the partial oxidation at 700 and 1000°C. The parameter of pseudo-current density which was related to the active area was defined as i^*(= i•Q_A^-1), where Q_A was the anodic electric charge calculated from cyclic voltammogram, and applied for the pseudo-OER specific activity. The Zr compound film prepared under 8.6 mPa of partial pressure of oxygen at the base temperature of 200°C during the sputtering had the largest i^* of Zr compounds in this study. From chronoamperometry measurements, the decrease rate of i^* on the Zr compound film of the best OER activity was smaller than that of IrO₂ powder. In addition, the Zr compound film was higher not only in OER activity but also in stability than the Zr compound powder in this study.

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Fe-doped SnO₂ thin films were deposited by the photochemical method. The SnO₂-deposition solution is an aqueous solution containing 10 mmol/L of SnSO₄. A small amount of the solutions was repeatedly dropped on the glass substrate and irradiated by the UV light. For the Fe doping, FeSO₄ was mixed in the SnO₂ deposition solution, or another solution for the Fe doping was prepared separately and alternately dropped and irradiated. The Auger electron spectroscopy measurement revealed that Fe was contained in the deposited thin films. The dependence of electrical properties of the films on annealing temperature was studied. The Fe-doped SnO₂ thin films showed enhanced electrical conductivity after 300 and 400°C annealing in a nitrogen atmosphere.

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Superlattice composed of alternative growth of 7 units CaFeOX (CFO) and 5 units BiFeO₃ (BFO) for 14 times was grown on 7 units grown LaFeO₃ (LFO) / SrTiO₃(001) substrate. The 7 units LFO was used as calibration layer for CFO/BFO superlattice because an intensity oscillation of a RHEED specular spot of LFO 135.4 units single layer maintained until the end of the growth, and the estimation thickness from initial RHEED oscillation period was consistent with the XRD result. Smooth surface and streaky RHEED pattern were observed in the superlattice. From the result of 2θ-θ XRD, we can clearly see the satellite peaks from -4 to +4, indicating the superstructure with smooth interface. Superstructure unit was calculated at 4.750 nm with an average lattice parameter of 0.3848 nm. Those values were consistent with the result of low angle x-ray reflection with the error less than 0.45%. The initial deposited LFO film thickness was 2.817 nm (7.10 units). Superstructure unit was composed of 2.564 nm (6.942 units) of CFO and 2.165 nm (5.319 units) of BFO, and totally 4.729 nm.

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The magnetoelectric Cr₂O₃ films were deposited on r- and c-cut sapphire substrates. From the results of surface roughness Ra, the substrate temperature of 580°C and the O₂ / Ar ratio of 0.25 was optimized condition. The Ra of c-oriented Cr₂O₃ film was much better, one-tenth than that of r-oriented film. In the reciprocal space mapping (RSM) around {10-110} and {1-1010} planes of the c-oriented film, substrate peak appeared rotating every 120 degrees along the □ direction with the rotation axis of the [001] direction, however, film peak appeared every 60 degrees. In the meantime, both of peaks of substrate and film were observed in the RSM around (2-2010), while no peaks appeared in the RSM around (2-208) in the r-oriented film. From those of the RSM results, the c-oriented film grew with twin crystal structure, but r-oriented film grew without twin.

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  The microstructure and elemental distribution of gadolinium-doped ceria (GDC) thin film electrolyte, Ni-GDC cermet anode and the interface between them were characterized by high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX) operated in scanning TEM (STEM) mode. HR-TEM and SAED results demonstrate inhomogeneous microstructures formation, i.e. nano-domain and superstructures, at interfacial region. STEM-EDX mapping and line scan analyses illustrate that not only can Ni diffuse into GDC grains as previously reported, but also Ce and Gd cations can diffuse into metallic Ni particles with equal diffusion length as that of Ni diffusion. Therefore, the mutual diffusion and related microstructural evolutions are elucidated to be the dominating factors that lead to the interfacial layer formation between anode and electrolyte, which is identified to have considerable influence on the ionic conductivity behavior in intermediate temperature solid oxide fuel cells.

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  To design the new proton conductor, the relationship between the proton conductivity in Ba₂In_2-x(Zn_1/2Zr_1/2)_xO₅ compounds and the crystallographic parameters (i.e. lattice constant, unit cell volume, phase transformation temperature between brownmillerite phase and perovskite phase) was investigated. Ba₂In_2-x(Zn_1/2Zr_1/2)_xO₅ (0.4≦x≦2.0) consisted of single phase of cubic perovskite-type cubic structure. And single phase of orthorhombic brownmillerite-type structure was obtained in the composition range of Ba₂In_2-x(Zn_1/2Zr_1/2)_xO₅ (0.0≦x≦0.3). The temperature dependence of electrical conductivity observed for Ba₂In_1.7(Zn_1/2Zr_1/2)_0.3O₅ which consists of single orthorhombic phase corresponded to the temperature dependence ofelectrical conductivity observed for Ba₂In₂O₅ which is high temperature form of Ba₂In₂O₅. The phase analysis by means of high temperature XRD analysis indicates that the aforementioned temperature dependence of electrical conductivity observed for Ba₂In_1.7(Zn_1/2Zr_1/2)_0.3O₅ was attributable to the conducing behavior in tetragonal Ba₂In_1.7(Zn_1/2Zr_1/2)_0.3O₅ sample which phase was observed above 800K. Also, the proton conductivity in Ba₂In_1.7(Zn_1/2Zr_1/2)_0.3O₅ sample was observed in humidified condition below 723K. Based on all experimental data, it is concluded that co-doping of Zr cation and Zn cation into In site of Ba₂In₂O₅ is effective for design of high quality oxide proton conductor.

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The intermetallic compounds which are mainly used for the thermoelectric power generation system are unstable at high temperature. Therefore, we studied thermoelectric property of ZnO doped with group 3B elements periodic table, which can be expected to be a good candidate of thermoelectric material with high performance. The electrical conductivity (σ) and See beck coefficient (S) were evaluated under He atmosphere from 673 to 1073K. Although the electrical conductivity was showed maximum value for sample with r_av. = 0.054 nm, the Seebeck coefficient did not change for all samples. This fact was considered that the increase in electrical conductivity was caused by improvement of carrier mobility, and the improvement of carrier mobility may be ascribed to the decrease in lattice distortion which caused by co-doping. Power factor (S²σ) of Zn_9.993Ga_0.0023In_0.0047O showed higher value than that of Zn_9.993A_0.007O (A = Ga, In). Thus, the co-doping was effective for the improvement of power factor.

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  For solar cell application open circuit voltage and short circuit current influence the solar efficiency directly. Carrier concentration, width of the depletion layer and other some related parameters influence on the amount of the open circuit voltage and short circuit current. Some equations can give the idea to improving the solar cell efficiency of a homo or heterojunction. For this a relation among the width of the depletion layer, carrier concentration and static electric potential of a step heterojunction has derived by the help of Gauss law.

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Block copolymer free-standing membrane with hexagonally packed and penetrated cylinders is fabricated in 5 cm × 5 cm of area and 1.2 µm of thickness by using a sacrificial layer of indium-tin oxide (ITO) layer which can be dissolved with a dilute hydrochloric acid (HCl) solution immediately. Photocross-linkable liquid crystalline block copolymer consisting of poly(ethylene oxide) and liquid crystalline poly(methacrylate) with chalcone mesogens as photocross-linkable unite, PEO-b-PMA(rChal), was utilized in this report since this film affords hexagonally packed and normally aligned PEO cylinders in long range ordering. Photocross-linking in chalcone mesogens and dissolution process of the sacrificial layer using aqueous solution play the dominant role in the large-area fabrication of the free-standing membrane without any defects. The orientation of PEO cylinders in the membrane with ～0.8-17 µm thickness was investigated based on GISAXS measurement. The perpendicularly oriented PEO cylinders were observed in the membrane with up to 1.2 µm of thickness

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A series of poly(3-decylthiophene)s (P3DT) having allyl, phenylethynyl, or pentynyl as the end-groups were synthesized by catalyst-transfer polycondensation reaction, to give the regioregular polymer with well-controlled molecular weights and narrow polydispersities. Although the amphiphilic diblock copolymers of P3DT and poly(ethylene oxide) (PEO) as a hydrophobic and a hydrophilic segment was synthesized via Click reaction, the introduction yields of PEO at the end of P3DT chain was low of 4-34 %, which might be attributable to the aggregation of end-functionalized P3DT and/or PEO segments in the reaction mixture.

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The polystyrene-b-poly(vinyl methylsiloxane) (PS-b-PVMS) main chain was synthesized via the anionic polymerization of styrene and cyclotrisioxane momomer consecutively. The catalytic hydrosililation of vinyl groups with the hydrodisiloxane tethered by liquid crystalline stilbene mesogen unit afforded a diblock copolymer PS-b-PMS(Stb) with the narrow polydispersity (M_N = 52100, M_W/M_N = 1.25). This diblock copolymer exhibited liquid crystalline phase, and gave a lamellae-like nanostructure in the thin film thermally annealed at higher temperature than the isotropic-to-LC transition point.

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Silica (SiO₂) nanopillar array was fabricated using microphase-separated block copolymer (PEO_m-b-PMA(Az)_n) thin film as a nano-template. Sol-gel precursor was selectively introduced into perpendicularly oriented poly(ethylene oxide) (PEO) nanocylindrical microdomains on a SiO₂ sol derived adhesive layer/Si wafer. The PEO cylindrical microdomains could give perpendicular orientation to the SiO₂ adhesive layer. The SiO₂ adhesive layer would support controlling the perpendicular orientation of SiO₂ nanopillar array due to increasing attachment area and forming Si-O-Si networks between SiO₂ nanopillar array and the SiO₂ adhesive layer during calcination process.

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The phase-separated structures of the mixed Langmuir–Blodgett (LB) films of behenic acid and hybrid carboxylic acid (FmHnA: C_mF_2m+1C_nH_2nCOOH) are investigated by focusing on the effects of the chemical structures of the hydrophobic part of FmHnA and the subphase temperature on the size and shape of the domains. Domains at the micrometer length scale and at the nanometer length scale form when m+n ≤ 16 and m+n ≥ 18, respectively. This is explained by considering the effect of the chemical structures of FmHnA on the line tension. With an increase in subphase temperature the size of the domains increases irrespective of the size of the domains. The size of the domains affects the manner in which the domain shape changes.

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Zn_1-(x+y)Ga_xIn_yO (x+y=0.005, 0.007 and 0.009) compounds which consist of single phase of hexagonal ZnO were prepared using solid state reaction method. To develop the design paradigm for fabrication of high quality thermoelectric ZnO based materials, the relationship between the average ionic radius of dopants in Zn site of samples and ZT values was examined. The experimental results indicated that the ZT value was improved by using concept of average ionic radius of dopants for development of high quality thermoelectric ZnO based materials.

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Poly(ethylene oxide) graft copolyamides (PA-g-PEO and PA-g-PEOC) were prepared by a macromonomer method, and the effect of the PEO segment lengths or the polar end group of the graft copolymers on the CO₂ permselectivity was investigated. In addition, poly(ethylene oxide) and polydimethylsiloxane randomly graft copolyamide (PA-g-SEr) were prepared by a macromonomer method, and the effect of copolymer composition on the gas permeability was also investigated. The obtained polymers were soluble in aprotic polar solvents, such as DMF, NMP and DMSO. Then, the tough and flexible membranes could be prepared by solvent-casting method using NMP as solvent. The CO₂ permselectivity of the polymer membranes was evaluated. The CO₂ permeability coefficient of PA-g-PEO membrane containing the longer PEO segment was 32.6 Barrer, and the selectivity of CO₂/N₂ was nearly 50. It was also found that the moderate introduction of polydimethylsiloxane side chain was effective to increase the CO₂ permeability coefficient to 39.2 Barrer while maintaining the selectivity of CO₂/N₂. On the other hand, the introduction of the polar diethylcarbamoyl group into PEO chain end caused the decrease of the CO₂ permeability coefficient to 5.96 Barrer.

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  The gas diffusion coefficients of H₂, O₂, N₂, CO₂, and CH₄ at 308 K of a polydimethylsiloxane (PDMS) dense membrane with a focus on the free volume morphology were investigated based on molecular dynamics simulation. Using the constructed amorphous cell of PDMS, the density and glass transition temperature were determined. The fractional accessible volume (FAV) which can be determined by given radius prove size decreased dramatically from 0.46 to 0.17 with increasing probe radius. FAV at a probe radius of 1.74 Å, which was the same as the oxygen molecule radius (1.73 Å) based on kinetic diameter, was found to correspond to the fractional free volume (FFV) calculated using a group contribution method of Van Krevelen. The simulated values of the gas diffusion coefficients were consistent with the experimental values, and differed by 36% from the experimental ones. These simulated values decreased with increasing molecular size, such as the gas critical volume (H₂ ＞ O₂ ＞ N₂ ＞ CO₂ ＞ CH₄). This trend was the same as that in the experiment. We found that the interesting trend between FAV and gas diffusivity in PDMS. As the calculated values of FAV at each radius size of the gas molecules increased, the gas diffusion coefficients increased lineally, except for that of CO₂. Because CO₂ is higher value of critical temperature compared with the other gases, we considered that the reason for this deviation for CO₂ could be related to the gas condensability. Hence, FAV can be proved to be a more effective parameter than FFV in investigation for gas diffusion in polymer membranes.

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LiNbO₃ (LNO) nano-particles with the diameter of about 15 nm were prepared by mechanical milling using planetary ball mill from the commercial LNO powder. Rotation speeds of ball mill were 0 to 400 rpm, where the milling time was kept at 15 minutes. Magnetization was measured by SQUID magnetometer. The 400 rpm milled sample showed a tenth larger saturation magnetization than that of BaTiO₃ with vacancies.

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CrO₂ is a ferromagnetic half metal with 100% polarization of conduction electrons, and MgO has been known as to be good barrier for TMR. We prepared the granular junctions from the mixture of CrO₂ and MgO. The field dependent resistivity of (MgO)_x(CrO₂)_1-x showed that the magneto-resistance ratio becomes maximum at x=0.6.

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Polysilanes having some kinds of 2-substituted ethynyl group directly connected to the polymer backbone were synthesized. The effects of π-conjugation system in the side chain on the optical properties of the polysilanes were studied. The polysilanes having ethynyl moiety showed no typical absorption peak arising from polysilane backbone. It was suggested that polysilanes having ethynyl moiety were random coil forms because of sterically unoccupied silicon atom. Polysilane having o-tolylethynyl group, which would show the most steric hindrance in this study, exhibited the longest wavelength of absorption peak (292 nm). We attempted to stabilize polysilane by means of assist from the π-conjugation system, which was extended by curing the cast film of the polysilane at 300°C for 20 min considering UV-Vis absorption spectra, although the chemical structure was not reveal in detail.

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Recently, from a point of environmental problems, oxygen gas sensors attract attention of controlling the exhaust gas. The Ga₂O₃ has an oxygen detection characteristic at more than 900℃, so this material attracts much attention as an oxygen sensor at high temperature. The β-Ga₂O₃ films were prepared by the RF magnetron sputtering method. The effect of two kinds of substrates namely Si (100) and quartz on the oxygen detection characteristics were compared. As a result, it was found that the oxygen gas sensor fabricated on a quartz substrate had superior oxygen detection characteristics.

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We attempted to synthesize the polysilarylenesiloxanes, PSAS, with sulfur atom or ketone group in order to investigate effects of the introductions of them on thermal properties. PSAS having diphenyl sulfide moiety was successfully synthesized via the catalytic dehydro-coupling polymerization using palladium complex as a catalyst, which showed glass transition temperature, T_g, of 18°C and 5% weight loss temperature, T_5d, of 465°C in N₂. PSAS having acetal moiety was also successfully prepared via the same manner. Its T_g and T_5d are 42°C and 392°C, respectively. Additionally, this polymer exhibited a crystalline phase of melting point of 184°C, while a transformation from acetal into ketone group partially succeeded.

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In this research, the effect of heat treatment time on the performance recovery of Ti-Ni shape memory alloy (SMA) is investigated. The chemical composition of specimen is Ti-50.4 at%Ni, and cold working ratio is 30 %. At first, the specimen is heat-treated at 673 K for 3.6 ks. And then, the specimen is heat-treated for recovery of function after isothermal 1000 times loading-unloading test under constant strain. The heat-treatment temperature for performance recovery is 573 K, and heat-treatment time is varied from 0.6 to 3.6 ks. The functional deterioration process of specimens heat-treated for performance recovery is investigated by the isothermal loading-unloading tests under constant strain.
  Recovery strain and critical stress for inducing martensite increase with increasing heat-treatment time, and are saturated when heat-treatment time is more than 1.8 ks. Moreover, the number of cycle to failure increases with increasing heat-treatment time up to 1.8 ks, has a maximum at 1.8 ks, and then followed by a decrease. These tendencies are caused by a variation of the dislocation density owing to the variation of the heat-treatment condition. From these results, the optimal heat-treatment time for performance recovery is 1.8 ks when heat-treatment temperature is 573K.

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In this research, the effect of heat-treatment under constrained condition on shape memory properties of Ti-Ni shape memory alloy was investigated. The chemical composition of the alloy is Ti-50.4 at%Ni. The specimen shape is wire with 1 mm diameter and 20 mm gage length. Tensile strain at single heat-treatment is varied from 4 to 8 %, and the total tensile strain by several times heat-treatment is 40 %. The heat-treatment condition is 773 K for 18 ks.
The flexibility and expansibility of stent decrease with increasing tensile strain. In contrast, decrements of flexibility and expansibility during cyclic loading-unloading tests decrease with increasing tensile strain. These tendencies are caused by the difference of dislocation density due to the difference of the condition of the heat-treatment for expansion.

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Organic nanoparticles of violanthrone 78, a violanthrone derivative, were prepared by a reprecipitation method. The nanoparticles were annealed at 60°C and the nanoparticles were changed to J-aggregates. UV/visible spectra, fluorescence spectra, and fluorescence lifetimes of the nanoparticles prepared were measured. UV/visible spectra shows that the wavelength of main absorption band shifted from 610 nm to 630 nm after annealing, and the absorbance of the band increased by more than twice, and sharpening of the main band was also observed. Nanoparticles without annealing were not fluorescent. After annealing, fluorescence of the nanoparticles with a small Stokes shift was observed at 650 nm. From these results, it was suggested that the J-aggregates phase transition occurred by annealing. Fluorescence lifetime of the annealed nanoparticles was as short as 20 ps.

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The orthorhombic Pmnb phase of Li₂MnSiO₄ has been prepared by solid state reaction of Li₂CO₃, Mn(CH₃COO)₂⋅4H₂O, and highly dispersed SiO₂ at 800 °C and the subsequent slow cooling in Ar gas stream. The crystal structure was refined by the Rietveld method based on the model structure without disorder in the site occupancies, although some anomaly was observed for Mn sites. The DTA curve shows peaks at around 680 and 770 °C on heating and at around 510 °C on cooling indicating a reversible structural phase transition. From the in-situ XRD patterns at high temperature, the first order phase transition from Pmnb to a distorted orthorhombic wurzite-type structure with the random arrangement of Li, Si, and Mn.

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Act of exchange from conventional refrigerant like 1,1,1,2-tetrafluoroethane to moderate molecular showing low global warming potential (GWP) is going on. Substituted refrigerants with low GWP are designed to readily decompose in atmosphere. It is, therefore, feared that the life shortening of the refrigerant is accelerated in the presence of mechanical parts of vehicle air conditioner including metal(s). In order to evaluate the stability in the short term, refrigerants including 2,3,3,3-tetrafluoropropylene with low GWP was contacted many times with highly dispersed metal on carrier in the closed circulating system. Finally, the evaluation of relative stability of refrigerants was successfully achieved within ca. 1.5 hours. Thus the evaluation term was able to shorten dramatically compared to the conventional method.

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Ruthenium based industrial catalysts have been manufactured exclusively using ruthenium chloride as RuCl₃･nH₂O which shows water soluble properties. Activation process, usually hydrogenation, is required to remove chlorine and obtain low oxidation state of ruthenium species which gives excellent activity and selectivity. Recently, for instance, small packaged co-generation system equipped with a PEM-FC (polymer electrode membrane - fuel cell) has been noticeable technology, therefore, the way to obtain instantly active state of catalyst at startup stage in the co-generation system becomes important. In this study, when the precursor of Ru/SiO₂ catalyst obtained by conventional impregnation was soaked in the diluted aqueous ammonia, the hydrogenation of 1,3-butadiene rapidly proceeded on the catalyst abbreviating reduction procedure. The conversion of 1,3-butadiene on the catalyst was closely related to the existence of the deeply reduced ruthenium species on carrier such as silica. Thus the catalyst treated with aqueous ammonia gave ruthenium species with low oxidation state despite having abbreviated reduction procedure.

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Cone-shaped graphitic whiskers (CGWs) are highly ordered turbostratic carbons with stacked hexagonal carbon layers that are conically distorted. These whiskers are produced by vapor phase carbonization with β-SiC crystal additive serving as the seed. CGWs can be generated from wood using the pyrolysis gas produced by wood, and the CGWs grow in the wood cell lumen that serves as the reaction field.
In this study, sulfuric acid intercalation of whole wood block char encapsulated with CGWs was investigated. For intercalation, the wood block char encapsulated with CGWs was used as the anode of an electrochemical oxidation “cell” under a constant electrical current in sulfuric acid. Evidence for the intercalation of both wood cell char and CGWs was obtained by Raman microspectroscopy. Exfoliation of the CGWs was observed by electron microscopy with the delamination of stacked hexagonal carbon layers owing to gasification of the sulfonate ions remaining between the hexagonal carbon layers as a result of electron irradiation. Thus, this as-is whole block treatment enabled the exfoliation of the CGWs encapsulated in the wood without the need for separation from the wood cell char.

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Crystallized mesoporous carbon (CMC) prepared by carbonization of softwood (S) and hardwood (H) with 2 wt % nickel and 3 wt % iron were washed with acid, mixed with cornstarch as matrix, and then molded into disk specimens for evaluating electro- conductivity. H-derived CMC had higher filler ability than the corresponding S-derived one irrespective of metal species. This can be understood by higher mesoporosity with probably better dispersion in the matrix for the former. CMC derived from iron-loaded H was comparable to Ketjenblack, excellent conductive carbon in the filler ability. Thus combination of H with iron was the most favorable for this purpose.

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A film sample is prepared for poly(cyanobiphenyl ethylacrylate), abbreviated to PCB2A, to investigate transparent/opaque change in response to thermal history. PCB2A is thermotropic type liquid crystal, the distance is not far between glass transition temperature (T_g) and the nematic–isotropic transition temperature (T_N-I). The kinetics from isotropic to nematic phase strongly depend on the molecular weight(M_w) If M_w is high, the transition becomes slow dynamics; for example, it takes more than 60min from isotropic to nematic phase by the temperature jump. This large time lag enables us to control the transparency of PCB2A film by means of a simple thermal treatment slightly below T_N-I. The results of the measurement of transmitted light volume for films prepared from samples of different M_w can be interpreted in terms of the kinetics of isotropic-nematic phase transition.

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FeSi_x films were deposited on Si (100) substrates by RF-sputtering method using an FeSi₄ target. Post-annealing was carried out at temperatures in the range of 400-900°C for 10 min in Ar gas. The surface of FeSi_x films was observed by optical microscope and crystal quality of the films was analyzed by X-ray diffraction (XRD) measurement. Sheet resistance of the deposited films was measured by four-point probe method. The films deposited using an FeSi₄ target were completely transformed to β-FeSi₂ after annealing over 500°C and Si (111) XRD peak was observed at 28.4° in the films annealed over 800°C. Cracks were not observed on the surface of the films annealed at as high as 900°C when deposited using an FeSi₄ target, although the films deposited using an FeSi₃ target had cracks on the surfaces after annealing over 700°C.

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