Fe–Pt nanoparticles fabricated by the polyol process have been reported as a possible alternative material for use in catalytic electrodes for polymer electrolyte fuel cells (PEFCs). Catalytic Fe–Pt alloys suffer from a problem where Fe dissolves from the alloy. Here, we examined the dissolution of Fe into the electrolyte for various composition ratios of Fe to Pt. We have also described the characteristics of Fe–Pt nanoparticles on the basis of XRD, XRF, TEM-EDX and electrochemical measurements and have discussed the rinse effect of Fe–Pt nanoparticles in acid solutions and the annealing effect of Fe–Pt caused by structural phase transitions from disordered fcc to ordered fct phase structures.

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Novel, bulk multiwall carbon nanotubes (MWCNTs) sintered with polycarbosilane (PCS) as a binder agent were fabricated by spark plasma sintering (SPS), and their microstructure and properties were investigated. Sintering was done with 20-60MPa pressure at 1200°C. SEM and TEM observations showed that the nanosized tube microstructure was preserved even after sintering, and tubes adhered to each other with the nanosized nodules of SiC pyrolyzed form PCS as revealed by X-ray diffraction. Bulk density and Vickers hardness were found to increase, whereas the specific surface area decreased, as PCS content and sintering pressure increased. Through animal experiments, the inflammatory reaction of CNTs/PCS material was found to be slightly increased with increasing PCS content. In conclusion, sintered CNTs had physical and mechanical properties close to bone, and their good biocompatibility based on tissue response served to pave their way as a suitable implant material in the future.

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Partially ordered L1₀-FePt nanoparticles synthesized in tetraethylene glycol by using polyol process is mostly polycrystalline in nature. In this paper, we attempted the preparation of single crystal L1₀-FePt nanoparticles by introducing nucleating and complexing agents during the synthesis. Though the synthesis of L1₀-FePt particles with constant physical properties was possible by using hexachloroplatinate (H₂PtCl₆) as the nucleating agent, particles remained polycrystalline in nature. However, when carboxylic acid was used along with H₂PtCl₆ FePt nanoparticles with more than 50 % ordering was realized under the optimum experimental conditions of Fe:Pt initial mole ratio of 52.5:47.5, 1 at% H₂PtCl₆ and five equivalent weight of Fe of carboxylic acid. The superlattice reflection lines of (001) and (110) in XRD pattern and the sextets from the Mossbauer spectroscopy at room temperature confirmed the presence of L1₀ phase. The coercivity and anisotropy field of these particles were 5. 6 kOe and more than 40 kOe, respectively.

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To clarify the effect of micro/nanosizing of materials onto biological organism, the particle size dependence of reaction of cells and tissue as investigated by both biochemical cell functional test and animal implantation test. Especially for nanoparticles the behavior of invasion and internal diffusion inside body was visualized using an XSAM (X-ray Scanning Analytical Microscope). The increase of specific surface area is usually counted as nanosizing effect which causes the enhancement of chemical reactivity and therefore toxicity of materials such as carcinogenicity found in 500 nm Ni particles for the long term implantation in the soft tissue of rat. Even biocompatible materials such as Ti and TiO₂ shows stimulus with the decrease of particle size. They cause phagocytosis to cells and inflammation to tissue when the size of particles is below 3 μm. For the size below 50 nm, they may invade into the internal body through the respiratory or digestive system and diffuse inside body. After compulsory exposure test of 30 nm TiO₂ particles through the respiratory system, the Ti mapping by XSAM showed the internal diffusion inside the whole body. Nanoparticles injected from caudal vein diffused with time course to lung, liver and spleen. The uptake of 30 nm TiO₂ particles through the digestive system and diffusion into these organs was also confirmed. These phenomena observed in biocompatible or bioinert materials are the nonspecific, physical particle and shape effects which occur independent of materials. Nanoparticles might be the objects whose existence has not been assumed by the living body defense system.

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We have succeeded in synthesizing ZnS films on substrates such as glass or Si wafer by using CBD (chemical bath deposition) method. These semiconductor films were photocatalytic and showed high productivity of hydrogen gas from the solution containing HS⁻ ions. From observation of SEM/TEM, it was found that the cluster film consisted of 100 nm sized agglomerated particles composed of nano-crystals. The result of EDS analysis for the cross-section of the film prepared by using FIB showed the presence of small amounts of oxygen along with zinc and sulfur. The information of the local quantum structures obtained from EXAFS/XANES analysis suggested that the cluster film has unique atomic-distribution and metastable electronic state different from bulk ZnS and ZnO. Based on the results of the above analysis, the relation between local quantum structures and properties was proposed.

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Biological reactions of nano/micro materials are discussed. Nanomaterials are biointeractive in the sense that their size and existence themselves possess the nature to induce the bioreaction to cells and tissue. They are also bioreactive, since they induce the intrinsic functions of biological organism in a generalized sense of both merit (bioactive) and demerit (toxic) for human beings. The bilateral nature of the potentiality for both high functional performance (nanotechnology) and unintentionally occurring biohazard (nanotoxicology) is the essential properties of nano/micro materials.

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Original approaches using plasma processing technology have been performed in order to develop fullerene- and nanotube-based materials with new functions, where various kinds of plasma sources are devised: pair-ion plasma, alkali-fullerene plasma, and radio-frequency reactive plasma. As a result of the process control of these plasmas we have succeeded in creating novel structured nano carbons such as fullerene dimers, alkali-metal encapsulated fullerenes, individually-aligned pristine single-walled carbon nanotubes, and alkali-metal and/or fullerene encapsulated single-walled carbon nanotubes.

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Stratified materials are defined as materials with nano-sized stratification that have been artificially controlled and designed. They are exemplified as a thin layer or stacked layers formed on surface of semiconductors. The present research is aiming at formation of controlled and designed stratification on surface of fine particles, leading to improvement of properties of fine particles which has been difficult to accomplish through the conventional particles engineering, and to development of novel properties created by the stratification.
Here, we describe the method of the development of the nano-size CdS catalyst with stratified structure that efficiently separates electron and hole during photolysis, especially, to produce hydrogen gas from hydrogen sulfide, H₂S. Furthermore, as an approach for the development of the practical use photocatalyst, ZnS-carbon nanotube complex was also made and examined. In a way, the stratified structure is considered to enable the production of a reaction system which simulates function in biological cells. Using this catalyst in the solution mixed with various materials such as, calcium hydroxide, seawater and H₂S, we succeeded in producing about 7.5l/h m² of hydrogen gas under the sunlight.

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Microstructure and pore-size distribution of the porous CaZrO₃/MgO in situ composites were modified by the addition of SiC. A porous composite with bimodal pore-size distribution (peaks at -1 μm and-17μm, porosity Vp=59%) was obtained by the pressureless reactive sintering of CaMg(CO₃)₂ (dolomite), ZrO₂ and SiC mixtures with a small amount of LiF in air. In an oxidative sintering atmosphere, SiC presumably acted as a "precursor" of SiO₂ at elevated temperatures, and contributed to the "partial" liquid phase sintering in the powder compact.

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The particles in magnetic fluid relaxes in the field direction through either Neel or Brownian relaxation. The relaxation mechanism is very much influenced by the anisotropy constant of the particle. In this paper, the relaxation mechanism under various states and conditions for magnetite and cobalt ferrite magnetic fluid in the temperature range of 83-293K is discussed by measuring the initial susceptibility of the system. Our results suggest that the magnetite magnetic fluid contains a mixture of non-superparamagnetic and superparamagnetic particles, whereas, the cobalt ferrite magnetic fluid contains exclusively of nonsuperparamagnetic particles. The results of local structure analysis on coprecipitated magnetite was comparable to that of Kamaishi magnetite except the distance between Fe and 0 atoms which was shorter. This suggests the possible vacancies in the octahedral sites in co-precipitated magnetite. In the case of coprecipitated cobalt ferrite, the Co and Fe atoms are well dispersed in the structure. The distance of the second nearest neighbor peak at Fe K-edge shows a decrease and at the same time at Co K-edge shows an increase meaning a slight difference in the cation distribution compared to cobalt ferrite produced by ceramic method.

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In order to improve bio compatibility and biological function of carbon nanotubes (CNTs), the surface of CNTs was modified by precipitating calcium phosphate compounds in a calcifying solution. To accelerate calcification process and efficacy of modification, a solution containing 6-times higher concentration of calcium and phosphate ions than that of physiological body fluid was used (the 6-times solution). Precipitation of calcium phosphate (Ca-P) upon CNTs was investigated, concerning the incubation time, influence of concentration of CNTs, elemental analyses of products and protein adsorption on the chromatographic column. Time-dependent observation of the reaction products by SEM indicates that the moss-like precipitation of Ca-P at first, then the granular bodies appeared at the beginning of incubation. These moss-like bodies seemed to be replaced gradually by granular bodies, and later, cotton fiber-shaped structures appeared. After 24 hr of incubation, the aggregation of spheroid bodies, composed of hydroxyapatite and CNTs, became the dominant constitute of the products. Ca and P were detected by EDS even when there were no precipitations in SEM image, giving the evidence that the surface CNTs was slightly covered by calcium and phosphate compounds from very early stage. This was further strengthened by a chromatographic result that the chromatography of slightly modified CNTs clearly showed the greater affinity for an acidic protein (albumin) than the unmodified CNT column. Combining with the evidence by EDS for Ca and P contents, this chromatographic result clearly indicates that the presence of calcium phosphates on the surface of CNTs, even though the observation by SEM could not detect it. The improvement of biocompatibility and the functionalization of CNTs could be done using calcification solution and the possible applications were suggested for the adsorption and release of various growth factors and medicines.

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With the increasing popularity of hybrid vehicles (HVs) and electric vehicles (EVs), the time required for their mass scrapping is also increasing. Therefore, attempts have been made to use storage batteries acquired from scrapped vehicles as fixed storage batteries; however, these batteries have not been widely used because of their lack of versatility and poor cost-effectiveness. In this study, we developed a versatile control program and hardware to use all vehicle-mounted storage batteries as stationary storage batteries regardless of the vehicle type, using the entire vehicle-mounted storage battery and parts. As a result, we realized batteries with a more stable system whose selling price was lower than that of new batteries. Moreover, attempts are in progress to develop a high-performance energy storage system that is not possible using fixed batteries by developing a system that integrates high-power (e.g., in HVs) and standard-power (e.g., in EVs) storage batteries. To use vehicle-mounted storage batteries from HVs and other vehicles as fixed storage batteries, we analyzed their charge/discharge control signal data to construct a basic algorithm for the control program, and we further succeeded in developing an original hardware design for incorporating the storage batteries into the system.

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カーボンナノチューブ（CNTs）にアモルファスホウ素を添加し，プラズマ焼結法で固化することで，炭化ホウ素（B₄C）を析出させて強化したCNTs中の未反応アモルファスホウ素と析出したB₄Cの化学的分離定量法を検討した．B₄Cは無機酸には溶解しないが，アモルファスホウ素は溶解することから，析出強化したCNTsを7 N硝酸で処理することでアモルファスホウ素を溶解し，析出したB₄Cは未溶解残さとしてろ過分離した．ろ過分離したB₄Cは，ホウ素の揮散を防止するために水酸化カルシウム水溶液で湿らせた後に灰化し，炭酸ナトリウムで融解することで溶解した．ろ液および未溶解残さ中のホウ素量をICP－発光分光分析法でそれぞれ定量して，アモルファスホウ素とB₄Cに相当するホウ素濃度を求めた．

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A new method to synthesize fullerene and sulfur compounds, C₆₀S₁₆ and C₇₀S₁₆ compounds of about 1 mm length, has been developed. The C₆₀S₁₆ crystal is a C-centered monoclinic structure of a=2.0874(1) nm, b=2.1139(1) nm, c=1.05690(6) nm and β=111.9 degree. The C₇₀S₁₆ compound has a primitive monoclinic structure of a=1.5271(2) nm, b=1.49971(7) nm, c=2.18024(9) nm and β=109.791(1) degree. The crystalline structure of these compounds is constructed by fullerene and S₈-rings. A very small amount of charge-transfer between fullerenes and sulfur rings are expected by first-principle calculation.

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Synthesis of nanometer size core-shell structured NiCo particles via the modified polyol process is described. Cobalt particles of about 20 nm with hcp crystal structure was synthesized by the use of appropriate type of glycol, hydroxyl ions, adsorbing ions, nucleating agents and other reaction conditions, which otherwise were few microns in diameter and fcc in structure. It is proposed that the suitable control of those factors permitted the enhancement of the metal forming reaction rate. The room temperature (RT) saturation magnetization (M₅) and coercivity (H_c) of the fcc-cobalt particles of few hundred nanometer in diameter ranged from 135 to 150emu/g and 35 to161 Oe, respectively. However, the 20 nm hcp-Co particles reported a M₅ of 67 emu/g and H_c, 535 Oe. On the other hand, the nickel metal particles of few tens of nanometer in diameter were synthesized by modifying the ethylene glycol EG-Ni(II) solution chemistry, which otherwise were sub micron in size and had plate-like morphology. The nickel particles were polycrystalline with fcc structure. The M₅ and H_c at RT ranged from 38 to 55 emu/g and 100 to 170 Oe, respectively. Though nickel was reduced easily than the cobalt in the absence of hydroxyl ions in EG, the reaction kinetics was reversed in the presence of hydroxyl ions. Thus, the unconstrained control of the reaction kinetics through the manipulation of the reaction parameters permitted the co-reduction of Ni and Co ions and facilitated the synthesis of nanocrystalline core-shell structured NiCo particles. The TEM-EDX analysis revealed that the core was rich in Co and the shell was rich in Ni. The magnetic properties of the particles depended on the Ni to Co ratio and the M, of these particles ranged between 50 and 150emu/g.

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We introduce biological applications and toxicity of carbon nanoutbes and carbon nanohorns, and discuss the interaction of these materials with the biological systems in vivo.

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In situ development of barium hexaferrite, BaFe₁₂O₁₉, particles in 3-mol%-yttria-doped zirconia (3Y-TZP) matrix was studied for the pressureless reactive sintering of 3Y-TZP, BaCO3, and y-Fe₂O₃ powders at 1250°-1400 °C for 2h. Fine-grained BaFe₁₂O₁₉ particles were homogeneously distributed in fine TZP matrix. Changing sintering temperatures could easily control the size of in-situ-developed BaFe12O19 particles. Submicrometer-sized BaFe₁₂O₁₉ particles were obtained at 1250°-1300 °C, allowing BaFe₁₂O₁₉ particles to be single magnetic domain structure. The 3Y-TZP/20-wt%-BaFe₁₂O₁₉ composite sintered at 1300 °C showed high magnetization and coercivity values, despite the low concentration of ferromagnetic phase. The composite also indicated moderately good mechanical properties.

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