Monolayer formation and behavior on a water surface of chromoionophore I (ETH 5294), a lipophilic isologue of oxazine-dye Nile Blue, were studied on the basis of surface pressure-molecular area (π-A) isotherms. Chromoionophore I formed a Langmuir-Blodgett film, and the stability of the monolayer appears to depend on the subphase pH as well as the degree of protonation in the chromoionophore I molecule. The chromoionophore I monolayers on the surface of subphase which was slightly basic showed favorite relaxation profiles, while it appeared to be hard and fragile on the acidic subphase. Adsorption experiment with ferritin has demonstrated the utility of chromoionophore I monolayer as a potential template although parameters which dictate the suitable conditions have to be further optimized to obtain a highly densely packed protein array.
The resistivity and high-frequency permeability of FeNiSiO/SiO2 multilayer granular magnetic films have been investigated to fabricate a magnetic film with high resistivity suitable for high-frequency micromagnetic devices. High resistivity is obtained by improving the electrical insulation of SiO2 associated with high-temperature deposition and concurrently by optimizing the microstructure, for example, the grain size of granular Fe-Ni metals and the thickness of SiO2 layers, which are independently controllable by an alternate sputtering deposition of FeNiSiO granular and SiO2. The high-frequency permeability are strongly affected by the Fe-Ni grain size as well as the Ni content, due to the influence of super-paramagnetism; the composition of the Fe-Ni grains primarily determines an anisotropy magnetic field (Hk), which is competitive with super-paramagnetism and is a key parameter that affects the high-frequency permeability. The permeability obtained in FeNiSiO/SiO2 films with a resistivity of 1.1 Ωcm is 460 at 100 MHz.
Recently, there has been considerable interest in the dielectric properties of the cubic perovskite CaCu3Ti4O12. The material has shown to have relatively high temperature independent dielectric permittivity over a wide temperature range from 100 K to 600 K. Below ～ 100 K the permittivity drops by almost three orders of magnitude, but is not accompanied by a structural phase transition. We studied CaCu3Ti4O12 hoping to find signatures of local structural distortions that may explain the observe anomalies in the dielectric properties. Experiments were carried out using synchrotron radiation at several temperatures between room temperature and 10 K. Reconsideration is necessary for interpreting a huge permittivity by the local disorder model.
Pb(In1/2Nb1/2)O3 (PIN) can be antiferroelectric (AFE), ferroelectric (FE) or a relaxor depending upon the perovskite B-site randomness. This is characterized by measurements of dielectric response, which shows behavior that is usually clearly in one of those three classes. In contrast, x-ray scattering studies suggest the presence of AFE correlation in the relaxor state and FE in AFE state. Weak phonon softening at zone boundary in relaxor state shows that the AFE correlation intrinsically exists in PIN, as does the corresponding elastic scattering at (h/2 k/2 0), while weak diffuse scattering around 333 Bragg reflection appears in AFE state suggesting FE correlation. These results will support our previous speculation that the AFE and FE correlations coexist in PIN (K. Ohwada et al., Phys, Rev. B77 094136 (2008)). Such a coexistence or competition is widely seen in the perovskite relaxor and the coexistence of FE and AFE correlations is essential for generating relaxor state.
PbTiO3 nanoislands were epitaxially grown on Pt/SrTiO3(100) by self-assembly using metalorganic chemical vapor deposition. The width and height of PbTiO3 nanoislands ranged from 30 to 200nm, and from 2 to 30nm, respectively. Piezoelectric constant (d33,PFM) measured by piezoresponse force microscopy (PFM) rapidly decreased with the height when the height was less than 10nm, suggesting intrinsic size effects. PFM also revealed that the domain configuration was dependent on the width of nanoislands. The critical width for single domain was found to be 50nm.
We present the behaviors of 90° and 180° domain walls under applying an electric field along the c axis in monoclinic Bi4Ti3O12 crystals. Piezoresponse force microscope investigations taking into account the two spontaneous polarization (Ps) components along the a (Ps(a)) and c (Ps(c)) axes reveal that 90° domain walls composed of the Ps(a) component impede the switching of the Ps(c) domains, leading to a lower remanent polarization along the c axis. 180° domain walls are found to be transformed from a curved configuration into a faceted configuration. These behaviors of Ps(a) domain walls raise the possibility of achieving material design using domain engineering for piezoelectric and optical applications of Bi4Ti3O12
Crystal growth at a high Po2 (oxygen pressure) is developed for Bi0.5Na0.5TiO3 single crystals based on defect chemistry at high temperatures. Bi0.5Na0.5TiO3 crystals grown at Po2 = 1 MPa show a saturated remanent polarization of 44 μC/cm2 along cubic, suggesting a spontaneous polarization of 54 μC/cm2 along cubic (polar direction) of rhombohedral Bi0.5Na0.5TiO3. High-Po2 heat treatments are demonstrated to be suitable for fabricating high-quality and high-performance ferroelectric and piezoelectric devices using Bi0.5Na0.5TiO3 crystals
Dynamical properties of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3 (x= 0.05, 0.08) are investigated by the broadband inelastic light scattering and the dielectric measurements. The dielectric constant shows a maximum at Tm (the maximum temperature of a dielectric constant) where rhombohedral and tetragonal phases coexist. A central peak (CP) is clearly observed around Tm by the inelastic light scattering measurements, and it indicates that the polarization relaxation plays a key role for the maximum of the dielectric constant. We consider that the broad one is attributed to the overdamped soft phonon, while the narrow one is related to the relaxation of the local polarizatio. We suggest two possible origins of the local polarization relaxation.
Effects of isovalent substitutions in the Mn(Cr)- and Bi-sublattices of BiMnO3 and BiCrO3 on the magnetic, structural, and chemical properties have been studied. Phase diagrams in the whole compositional range were constructed for BiMn1-xScxO3, BiMn1-xCrxO3, and Bi1-xRxMO3 (R = Y and La, M = Cr and Mn). BiMn1-xScxO3 and BiMn1-xCrxO3 keep the monoclinic C2/c structure at RT for all x values; a spin-glass transition was found for x ≥ 0.4 in BiMn1-xScxO3 and at x = 0.4 and 0.5 in BiMn1-xCrxO3. Magnetic phase diagrams of BiMn1-xScxO3 and BiMn1-xCrxO3 are similar to each other for x ≤ 0.5. In Bi1-xRxMO3, the Pnma modification is stabilized very fast with x; the Pnma phases show antiferromagnetic transitions with weak ferromagnetism.
Epitaxial thin films of Bi1-xBaxFeO3 have been deposited by sputtering on LaAlO3 and SrTiO3 substrates with and without conducting buffer layers of paramagnetic LaNiO3 and ferromagnetic La0.7Sr0.3MnO3, and their structural, magnetic and ferroelectric properties have been investigated. It has been shown from magnetic and ferroelectric characterization that Bi1-xBaxFeO3 epitaxial films in a thickness of 300 nm exhibited reasonable multiferroic properties at room temperature. Spin-filter junctions consisting of a La0.7Sr0.3MnO3/ Bi1-xBaxFeO3/LaNiO3 epitaxial heterostructure have been fabricated using photolithography and ion milling. The junctions with a Bi1-xBaxFeO3 layer thickness of 4 nm exhibited nonlinear current-voltage (I-V) characteristics with the barrier height of 0.37 eV, and MR effect at 4.2 K, indicating that the Bi1-xBaxFeO3 ultrathin layers serves as ferromagnetic tunnel barriers in spin-filter junctions.
Nano-sized domain structures in the cubic phase of (1-x)BiFeO3-xBaTiO3 with 0.33＜x＜0.60 were investigated by the transmission electron microscopy (TEM). From high-resolution TEM observation, it is revealed that the cubic phase in the x=0.35 and 0.50 compounds is characterized as nano-scaled coexisting state of the polar rhombohedral structure and the non-polar cubic one, which should be regarded as the psudo-cubic phase. On the other hand, both P-E hysteresis measurements and the TEM experiments revealed that the cubic phase without any distortion due to the coexisting state appears in the x=0.60 compound at room temperature. These results indicate the presence of the phase boundary between the psudo-cubic phase and the cubic one in 0.50＜x＜0.60.
We have investigated the physical properties and local atomic structure of LuFe2O4, a material belonging to the multiferroic system RFe2O4 (R: rare earths) which shows the new type of ferroelectricity owing to the charge ordering of Fe ions. Magnetic measurements showed the ferromagnetic ordering of Fe spins at ～230 K, as reported previously. From dielectric measurements, the dielectric constant (ε') of ～10000 was obtained at around room temperature. In addition, a peak of ε' was observed near the charge-ordering temperature (～330 K). The peak temperature was insensitive to the frequency of AC electric field; this behavior is different from that found in a previous study. The pair-distribution function analysis on a high-energy X-ray diffraction pattern revealed that LuFe2O4 has the systematic modulation of the local atomic displacement.
Ferromagnetic (FM) domain structures in double-exchange manganites La1-xSrxMnO3 (x=0.175, 0.30) were investigated by low-temperature Lorentz transmission electron microscopy (TEM). It was found that the rhombohedral-to-orthorhombic transition around 185 K in La0.825Sr0.175MnO3 accompanies drastic change from large FM domains with the 1 μm size to the 100 nm sized FM one with the stripe pattern. By partial substitution of non-magnetic Al ion for Mn one, the FM domain structures with the straightforward stripe pattern in the orthorhombic phase of La0.825Sr0.175MnO3 changed into the FM domains with the wavy stripe pattern and, in addition, some defects such as the dislocation were often observed. On the other hand, no changes of the FM domain structures were found by partial substitution in the rhombohedral phase of La0.7Sr0.3MnO3.
Epitaxial NbN/ferromagnetic material (Co and Co2MnGe) multilayers have been grown on MgO (100) substrate and the spin polarization of the ferromagnetic materials has been investigated by using the multilayer junctions. The Co2MnGe layers have been deposited on MgO//NbN and the inverted structure (NbN layers on Co2MnGe films) has been also made. The epitaxial relationship between NbN and Co2MnGe layers with an in-plane 45°rotation was confirmed for the two types of multilayer structures. Andreev reflection measurements on these junctions and the modified Blonder-Tinkham-Klapwijk (BTK) analysis have shown that the spin polarization values of Co and Co2MnGe are 0.38 and 0.51, respectively. These values are in good agreement with previous data obtained by using the point-contact Andreev reflection (PCAR) technique. The results suggest the potential of the epitaxial NbN junction method as a measurement technique of spin polarization.
(100)-oriented epitaxial Fe3Si films grown (100) Si substrates with an epitaxial magnesia (MgO) buffer layer by rf-magnetron sputtering. X-ray pole figure measurements revealed that the Fe3Si layer is epitaxially grown on MgO buffer layer with an orientation relationship of Fe3Si(100) // MgO(100) with Fe3Si // MgO. The coercive forces (Hc) of epitaxial films was approximately 60 Oe, and the saturation magnetizations (Ms) was 750 emu/cm3.
Composite thin films containing PVDF and TiO2 have been prepared by using spin coating technique. The highest pyroelectric activity as measured by quasi static method is shown by the composite thin films containing 20 wt% of TiO2. The doping of TiO2 in PVDF thin films has reduced the optimum poling electric field needed to be applied in order to observe pyroelectric activity in the composite thin films. Plasma treated composite thin films with Argon (Ar) gas has further increased the pyroelectric coefficient from 33 μCm-2K-1 to 83 μCm-2K-1. The investigation on the surface morphology and the phases of the composite thin film indicate that the change in the lamella structure and also the existence of the β-phase have contributed to the increase in the pyroelectric activity of the PVDF/TiO2 composite thin film.
Since austenite shows paramagnetic properties and ferrite and martensite do ferromagnetic ones, magnetic evaluation can be a good candidate for detecting phase transition. However, hence coercive force cannot distinguish ferrite from martensite under external magnetic field, magnetic measurement has not been used for quench hardening evaluation. By contrast, ferromagnetic specimens have inverse-magnetostriction properties, which can cause spontaneous magnetization under phase-transition stress during quenching process. Therefore, in this study, we have tried to develop a technique for quench hardening distribution analysis by sensing spontaneous magnetization caused from inverse-magnetostriction. From the results of the experiments, large spontaneous magnetizations were appeared in the specimen, which indicates partial martensite transformation in that area. However, residual magnetizations were observed in whole martensite or ferrite phase. Especially, high magnetic intensity was obtained in the area of multiple phases with residual austenite and martensite. The residual stress caused from the different molar volume between fcc austenite and bct martensite phase has an influence to the inverse magnetostriction phenomena emerging high spontaneous magnetization after quenching.
Size-controlled magnetite nanoparticles (MNP) with several dozen to several hundred of nanometers (nm) were prepared for hyperthermia of cancer. Nanoparticles of single-phase magnetite, as revealed by X-ray diffraction and magnetic property measurement, were synthesized by mean of an oxidation-precipitation method with iron (II) chloride as starting materials, which was oxidized to ferric salts by sodium nitrate (NaNO3) in an N2-deaerated sodium hydroxide (NaOH) aqueous solution. The particles size was controlled by adjusting the concentration of the reactant and the addition order of NaNO3. The resulting MNP had an average diameter ranging from 24 nm to 413 nm and their in vitro heat generations were measured in agar phantom under an alternating magnetic field (100 kHz, 23.9 kAm-1). Temperature rise in the agar phantom for MNP 24 nm in size was ΔT =55 ℃ in 30 second at a MNP concentration of 58 mg Fe ml-1. For MNP larger than 24 nm, heat generation decreased as particle size increased. Hysteresis loss mainly contributed the heat-generating mechanism. It is believed that MNP 24 nm in size is useful for in situ hyperthermia treatment of cancer.
Beta-tricalcium phosphate (β-TCP) precursors were prepared by chelation of calcium ions with phosphonic acid using calcium nitrate tetrahydrate (Ca(NO3)2 4H2O) and 2-phosphonobutane-1.2.4-tricarboxylic acid (C7H11PO9; PBTA) in distilled water in the temperature range of 60-130 ℃. β-TCP powder was then synthesized by heating the precursors at various temperatures. β-TCP precursors were gelled in three reactions. First, calcium ions were chelated with carboxyl groups in PBTA. Second, chelation of calcium ions with phosphonic acid and/or the dehydrated condensation of carboxyl groups with phosphonic acid, finally, dehydrated condensation of carboxyl groups occurred in the range of 100-130 ℃. Powder obtained after heating the β-TCP precursor prepared at 130 ℃ had a single crystalline alpha-TCP phase at 600 ℃, following by a single β-TCP phase at 800 and 1000 ℃. In addition, the crystallinity of the powder improved with an increase in the preparation temperature of β-TCP precursors, which accelerated gelation. The powder obtained at 600 ℃ was formed layers with submicrometer pores among particles, and the powder obtained after heating at and above 800 ℃, the particles formed a specific three-dimensional network. The particle sizes increased with an increase in the heating temperatures.
Bioactive ceramics are used for bone-repairing owing to attractive features such as direct bone-bonding in living body, because they have the ability to bond directly to bone. However, there is limitation on clinical applications due to their inappropriate mechanical properties performances such as higher brittleness and lower fracture toughness than natural bone. Organic-inorganic hybrids consisting of organic polymer and the apatite would be attractive as novel bioactive bone substitutes with mechanical performances analogous to those of natural bone. We attempted preparation of apatite-polymer hybrids from hyaluronic acid. It has been attractive for bone- and cartilage-repairing materials due to high biological compatibility. The hydroxyl groups in side chains of the hyaluronic acid were bridged by divinylsulfone. Dense films were obtained after drying at ambient pressure, whereas porous specimens were formed by freeze-drying. They were treated with 1 M-CaCl2 aqueous solution for 24 h. Ability of apatite formation on the specimens was examined in vitro using simulated body fluid (SBF, Kokubo solution). The specimens formed the apatite in SBF within 7 d, when they were previously treated with CaCl2 solution.
Improvement of bone integration ability of metallic biomaterials is needed for long-term stable fixation to bone tissues. Essential prerequisite for materials to show bone-integrating bioactivity is formation of apatite layer on their surfaces in body environments. Several functional groups have potential to trigger the apatite nucleation. In the present study, we attempted fabrication of bioactive titania layer which provides Ti-OH groups effective for the apatite formation on bioinert metals such as stainless steel and Co-Cr-Mo alloys by electrodeposition. Their bioactivity was evaluated in vitro in simulated body fluid (SBF). Bioactive titania layer was fabricated on both metals after heat treatment at appropriate temperature. Co-Cr-Mo alloys showed a tendency to form larger amount of the apatite than the stainless steel at the same temperature of heat treatment. This phenomenon was attributed to intergranular corrosion on the stainless steel and apatite depostion on the heat-treated stainless steels without the titania coating.
Two kinds of NiCuZn ferrites were prepared through the multilayer process using doctor blade method and the conventional dry pressing method. These have a difference only in a molding process, relationship of the bulk density and the sintering temperature showed almost the same tendency. However, these had large differences in microstructure. The mechanical properties and the magnetic properties of these ferrites were investigated, the results show that the mechanical properties depend on pore sizes and that the magnetic properties depend on grain size distribution.
We deposited the TiO2 films at various oxygen ion accelerating voltages under oblique incidence by using OIARE method and investigated the relationships between their structures and photocatalytic performances. The films deposited at 350 ℃, the accelerating voltage of 200 eV, and substrate tilt angle of 35 degree had excellent photocatalytic performance of 17.7 [μmol・l-1・min-1] for the decomposition of metylene-blue. The film has anatase structure with mean surface roughness Ra of 11.4 nm and mean crystallite size of 18.0 nm. The photocatalytic performance takes a maximum value around 200 eV and decreases monotonically with further increase of the accelerating voltage. The mean crystallite size of the film was decreased from 20.8 nm to 14.3 nm by the increase of the oxygen ion accelerating voltage from 0 to 1000 eV, which suggests that the high energy oxygen ion bombardment to the film surface will produce damages in the film and degrading the performance of the film. These results indicate that control of the energy of oxygen ions incident to the film surface is important to obtain a film with excellent photocatalytic properties.
Silica, silica/polymethylmethacrylate (PMMA) hybrid, and silica-particle blend silica films were successfully prepared on polybutylene terephtalate (PBT) substrate by dip coating using perhydropolysilazane (PHPS) as a silica source. The effect of thermal treatment on conversion from PHPS to silica was investigated in detail by scanning electron microscopy and Fourier transform infrared spectroscopy. Mechanical properties of silica and silica/PMMA hybrid thin films also were examined by the pencil scratch hardness test.
Porous Ni0.5Zn0.5ferrite ceramic was prepared using wood template. The wood specimen was treated with ammonia and infiltrated by slurry of nickel nitrate, zinc nitrate and iron (III) and sintered. The products contained mainly ferrite and hematite. The single phase of ferrite formed at 1200℃ for 8h, at 1300℃ for 6h, at 1400℃ for 2h and at 1500℃ for 1 h. The shrinkage of specimen size was obvious when sintered at higher temperature. SEM images confirmed that the sintering at higher temperature promotes the grain growth and at the same time causes the pore size to contract. The microstructure of wood retained.
Phase transitions in (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-xPT) under the zero-field heating (ZFH) after the field cooling (FC) were investigated. It was confirmed that a sharp phase transition below the diffuse phase transition region in PZN under ZFH after FC appears at 114℃. Sharp phase transitions in PZN-xPT mixed crystals under ZFH after FC were also found near the morphotropic phase boundary (MPB). We concluded that these sharp phase transitions in PZN-xPT correspond to the one between the tetragonal and rhombohedral phases.
(111)-oriented PZT(30/70) (PZT30) thin films were deposited on Pt/Ti/SiO2/Si substrate by Chemical Solution Deposition (CSD). The part of the Si substrates of 500 μm thickness were etched from back side by a wet chemical etching process. The depth of the back-etching was controlled by changing the etching time (residual Si; 25-180 μm). Dielectric and ferroelectric properties for the PZT30 thin films were measured at the back-etched and the un-etched part to clarify the effect of the residual stress on the electrical properties. (XRD).
We have fabricated the porous ceramics by gelcasting using agar and different surfactant. The effects of kind of the surfactants on structure of the porous ceramics and sound absorption were investigated. The structure of the porous ceramics including pore size and pore distribution, were easily controlled by changing surfactant. Fabricated porous ceramics performed good sound absorption properties. Moreover, each sample had a high sound absorption between 2000 Hz and 4000 Hz which is most strongly earshot in the audible range of the person.
Several types of Ag powder were used as electrode paste for a multilayer ceramic substrate. The shrinkage behavior of the silver powders was investigated during the sintering. Bending and cracking were frequently observed on the substrate when coarse powders that show a broad size distribution and aggregation were used. The shrinkage curve of the Ag paste obtained by spray pyrolysis agreed well with that of the substrate. Furthermore, the electrical properties of the Ag paste were also determined. The resistivity of a silver electrode sintered at 900℃ was about 2.00×10-6 Ω･cm.
Silver nanoparticles produced with a solid-phase thermal decomposition method were used for the preparation of a conductive paste supporting curing at low temperatures. The conducting paste was prepared by blending fine spherical silver powder and silver nanoparticles with a diameter of 20nm in order to reduce the electric resistivity of the electrodes. Although the viscosity of the conducting paste increased by about 25% after 60 days, it exhibited superior stability to dispersion in comparison to commercial paste. The electric resistivity of the electrode was of the order of 10-6Ωcm at a curing temperature of 200℃. Using this conducting paste, it is possible to print at widths of 20μm. The resistivity was further reduced by 1% in the high temperature test at 120℃, by 5% in the high humidity and high temperature test, and by 5% during the thermal shock test at temperatures ranging from -45 to 80℃.
LiMn0.9M0.1O2 (M=Mn, Ni, Zn, Cu) precursor powders were successfully prepared by ultrasonic spray pyrolysis. The main crystal phases of the powders calcined at 800 ℃ in argon atmosphere were found to exhibit orthorhombic structure. These powders showed a spherical morphology with the average particle size of 1.4 μm. The results of electrochemical measurements revealed that the discharge capacity of LiMnO2 increases by doping foreign metal such as Cu, Ni, and Zn. The discharge capacity of LiMn0.9Cu0.1O2 powders was found to be 220 mAh/g after 15 recharge cycles at the charging rate of 0.01C.
Pt thin films were exposed to Ar ion shower. The lattice spacing of Pt (111) increased with the duration of the ion shower treatment. The surface morphology was also modulated by the ion shower: the grain size was minimized when exposed to the ion shower for 8 min. The changes in the lattice spacing and surface morphology of the Pt layer resulted in changes in the structure and magnetic properties of Co-Pt nanopillars grown on its surface. The lattice spacing of Co-Pt (00.2) increased with the lattice spacing of Pt (111). Correlations were found between the magnetic properties of Co-Pt nanopillars and the structural properties of Pt underlayers and Co-Pt nanopillars. Coercivity increased with the lattice spacing of Co-Pt (00.2). Squareness increased with a decrease in the roughness of the Pt underlayer.
Transition metal (TM=V, Fe,Ni and Cu) doped rutile-type SnO2 were prepared by mechanical milling (MM). XRD results showed that the particle diameter d of host SnO2 powder was 16 nm after MM. The MM for the mixtures of TM oxide and SnO2 at 500 rpm for 15 minutes realized the 10 mol % TM doped SnO2 nano powders. Magnetization measurement showed that saturated magnetization Ms at 300K was 6.4×10-2 - 7.4×10-1, 5.1×10-4 and 5.6×10-4μB/TM-ion for TM=Fe, Ni and Cu. Thus the diluted ferromagnetic semiconductor powder of (TM)0.1Sn0.9O2 with Tc higher than room temperature were successfully prepared by MM, except for V0.1Sn0.9O2.
In this study, the syntheses of indolo[3,2-b]carbazole (INC) derivatives have been investigated, which possessed the planer and conjugated structure and showed the strong blue fluorescence by the irradiation of UV light. In order to improve the solubility of INC, N-alkylated INC derivatives were prepared by the reaction of INC with NaH followed by the addition of alkyl halides, the carbon numbers of which were C1 - C10. The obtained alkylated INCs were soluble in some solvents, and the unique thermal properties were observed for the alkylated INCs with a long alkyl chain, which became amorphous after melting and showed the mesomorphic-like transitions. According to the fluorescence spectroscopy, these alkylated INC derivatives exhibited the strong emission, the quantum yield of which was about 0.50. On the other hand, the INC derivative containing an octyl group and a p-vinylbenzyl group at N-positions was prepared as a monomer compound to obtain polystyrene-type polymer with INC moiety by a radical polymerization. It was found that the polymer was a glassy polymer and the coating film was easily prepared. In addition, the obtained polymer exhibited a high thermal stability, which maintained the high emission property of INC moiety.
Graft copolyamides containing amphiphilic components in the side chains, alternately grafted aromatic polyamides containing polydimethylsiloxane (PDMS) and poly(ethylene oxide) (PEO) segments (PA-g-SEa), were prepared by a macromonomer method, which exhibited the high permeability of PDMS segment and the biocompatibility derived from the amphiphilic components. PA-g-SEa membranes were prepared by solvent casting method, and the gas permeability, the pervaporation property, the surface property and the biocompatibility of the obtained polymer membranes were investigated. From the results of permeation examinations of gases and aqueous ethanol solutions, PA-g-SEa membranes indicated the high permeability for most gases and liquids. In addition, the organic permselectivity was enhanced with the increase of PDMS segment length of these polymers. Furthermore, the amount of adhered platelets on PA- g-SEa membranes was much smaller than that on only PDMS grafted aromatic polyamide (PA-g-PDMS) membranes, which would be due to the effect of amphiphilic side chains.
Recently, manufacturing of high tolerance with promoting downsizing of various electronic components is required for lighter, thinner, shorter, and smaller communication equipments and electronics products using cellular phone and digital camera. In these circumstances, new type mirror polishing technology has been developed in order to polish nm-order for surface of ceramics, metal, and plastics. This technology can be polished high accuracy as follows: (1) acrylic resin of irregularity shape, (2) acrylic resin of film. This paper describes the possibility of the surface treatment of acrylic resin of the three dimensional nano-level polishing using MCF(magnetic compound fluid).
Quaternarization of poly(4-vinylpyridine) (1: Mn = 8.8 × 104, Mw/Mn = 1.98) or poly(4-vinylpyridine-co-styrene) (2: Mn = 1.3 × 105, Mw/Mn = 1.92, styrene content: 10%) with iodoethane was performed in DMF at 60 ℃ for 20 h to give partially quaternarized polymer supports (3 or 4, respectively). The content of pyridinium unit in 3 or 4 was estimated from 1H NMR spectra. The structure of the polymer supports was found to influence the catalytic activity. When the Heck reaction of 4-iodotoluene with styrene was carried out in 1.5 mol·L-1 KOH aqueous solution using 4b (pyridinium unit content: 40%) as a polymer support, coupling product was obtained in 81% yield. The effect of base on the reaction and recycling of polymer supported palladium catalyst were thoroughly investigated.
Alumina-based composite containing 1vol%NiAl has been fabricated to study the toughening mechanism due to the oxidation-derived metamorphic layer on the surface. The development of the network structure substituting the boundary of the matrix-Al2O3 with the oxidation product NiAl2O4 induces enhanced crack deflection to improve the fracture toughness and strength from 3.6MPa･m1/2 and 539MPa (as-sintered) to 6.4 MPa･m1/2 and 701MPa at the oxidation time of 5h. However, excess oxidation causes the diffusion of the surface oxidation products into the bulk. The disappearance of the network structure results in the decrease of the toughness and strength.
In the present study, we report on the synthesis of iodic acid (IO3-)-doped TiO2 by solid state dispersion method using iodic acid as the precursor. The resulting material was extensively characterized by various sophisticated techniques such as XRD, UV-vis, SEM-EDX and XPS analysis. We explored the photocatalytic activity of IO3--doped TiO2 for the degradation of monocrotophos (MCP) in aqueous solution. The experimental results demonstrated that the presence of iodic acid in TiO2 could enhance degradation as well as mineralization of MCP in aqueous suspension. The possible explanation for the enhanced activity is discussed based on the formation of brookite phase. The brookite phase has been formed upon iodic acid loading with decrease in the percentage of anatase and rutile phases. In the present study, we conclude that the presence of all three phases of TiO2 with small particle size could be important for the enhanced photocatalytic activity.
By using the paper-casting process, Al2O3 filled paper was prepared, and sintered at 1500℃ to 1600℃. The tensile strength of Al2O3 filled paper had about 12MPa, which was almost the same as common cardboards. The Al2O3 paper ceramics sintered 1600℃ indicated the flexural strength of about 100MPa. The porosities were controlled by varying the amount of pulp fibers added during the papermaking process. The structure was characterized by bimodal pores.
Figure 7 in original paper (Yusuke Hiramitsu, Kiyotaka Hirose, Kenji Kobayashi and Hori, Influence of Water Transport Properties through Gas Diffusion Layer on Flooding in PEFC) which appeared in Transactions of the Materials Research Society of Japan, 33  1113-1117 (2008) was in error. The corrected Figure 7 is shown in this page. Specifically the value of limiting current density of 060-12 in Fig.7 is corrected in new version of the figure.