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The formability and sintering behavior of Ni60Nb15Ti20Zr5 metallic glass powder prepared by gas atomizing was investigated using precise hot press equipment. The structure of atomized metallic glass powder depended on its particle size, and only glassy phase was observed when the particle size was under 53μm. The glass transition temperature (Tg), crystallization temperature (Tx), and supercooled liquid region (ΔTx=Tx-Tg) of the Ni-based metallic glass powder was 838 K, 888 K and 50 K, respectively.The hot press sintering under the precise control of temperature and pressure was conducted. The densification behavior depended on only working temperature, and the Ni-based metallic glass powders were consolidated to nearly full density by hot press sintering with working temperature range 863-883 K. On the other hand, the crystallization behavior depended on working time as well as working temperature. In the experimental study this time, the hot press condition achieving both full densification and no crystallization was temperature of 868 K and pressure of 200 MPa. The sintered body of full densification and no crystallization exhibited high corrosion resistance nearly equal to Alloy C-276.

Metallic glasses are potentially applied for accurate micro parts because of their good formability and transferability as well as high mechanical properties and excellent magnetic properties. So the raw materials that the volume is precisely controlled are needed for a highly accurate processing. In this study, mono-sized spherical particles of Fe-Co-based metallic glass were prepared by Pulsated Orifice Ejection Method (POEM) and the capabilities of their micro-forming process in the glass transition temperature were investigated. Mono-sized spherical particles of Fe-Co-based metallic glass particles with 200-500 μm of diameter have been obtained by Pulsated Orifice Ejection Method (POEM). The XRD pattern of the particles shows only broad peaks without any crystalline peak. A bright field TEM image of the particles and the selected area diffraction patterns shows only halo patterns that indicate fully amorphous phase. DSC curve shows that supercooled liquid region was ΔT=48 K and a TTT curve can be constructed by isothermal DSC.

Preparation of high purity mono-sized silicon particles by Pulsated Orifice Ejection Method (POEM) was investigated. The results of simulation show that a large contact angle between silicon and orifice is necessary for particle formation on processing by POEM. Mono-sized silicon particles can be prepared with quartz orifice and tundish within in a wide variety by POEM. Analyses by Scanning Electron Microscope (SEM) and Orientation Image Microscope (OIM) show that the obtained silicon particles can be divided into two kinds according to their surface morphology and microstructure. One is grape-fruit type silicon particles, which are polycrystalline and consist of many grains mainly in random boundaries, and the other is lemon type, which consists of only two or three grains in twin boundaries with cross-sections sometimes found to be single crystal. Measurements of electrical resistivity on polycrystalline ingots formed in the same conditions as silicon particles show p-type behavior with a room-temperature electrical resistivity in the range 15∼60 Ωcm and carrier concentration less than 2×1016 cm−3 that are suitable for solar cell.

Hydrothermal growth of diamond particles and films was achieved during interaction of a liquid organic precursor (C2H3Cl3) and 10 M NaOH in the presence of diamond or cubic BN seeds at the temperature 300 °C and 1 GPa pressure. Synthesized diamond was thoroughly characterized by TG-DTA, SEM, EDX, TEM, Raman spectroscopy and had (220) preferable orientation according to XRD pattern in the case of the film.

A Co–V alloy and three kinds of PdNi–Cr–V alloys were designed for SiC joining. A wetting experiment was conducted with the sessile drop method. The interface reactions are discussed. Vanadium was found to be effective in controlling of the interface reaction.

Monosized germanium micro particles are prepared by a newly developed Pulsated Orifice Ejection Method (POEM). The obtained particles are categorized into two kinds of the microstructures as refined and coarse ones. The morphological difference is estimated to be determined by the undercooling level during nucleation. Actually, the increase in the temperature of the melt was effective in coarsening the microstructure, because the temperature of the melt intensely relates to the undercooling level. The transition temperature of coarse and refined microstructures is found to be 1300-1350K. Furthermore, a triggered nucleation could improve the crystallinity of the particles in the short separation.

This paper describes a fabrication process of Al/CNT composites and investigated their mechanical properties. CNT is a very useful reinforcement for composites since it has a very high strength and very high Young’s modulus. However, it is very difficult to distribute CNT in a metal matrix. Natural rubber was used as an elastomer and mixed with Al powder and CNT precursors to improve the distribution of the CNT in Al matrix. The resulting powder mixture was filled into Al alloy billets and encapsulated in vacuum atmosphere. The billets were then extruded with different extrusion ratios of 5, 10 and 20 at 673K. The composites were observed under optical microscope and FE-SEM, and the mechanical properties were evaluated by Vickers hardness and tensile tests. We succeeded in obtaining fully densified and finely extruded rod of Al/CNT composites of well distributed CNT by hot extrusion process. Observation of post extrusion micro structures revealed that CNT were not damaged by the hot extrusion process and their Vickers hardness and tensile strengths obtained were about twice compared to pure Al.

This paper describes a fabrication process of Al/CNT composites and measurement of their mechanical properties. It is a very useful reinforcement for composites since CNT has very high strength and very high Young's modulus. However, it is very difficult to distribute CNT in the metal matrix. Natural rubber, Al powder and CNT precursors were used to improve the distribution of the CNT in Al matrix. CNT distributed mixture with Al powder were obtained using the precursors produced by heat treatment in N2 atmosphere. The Al/CNT mixed powder filled up into Al alloy billets were encapsulated in vacuum atmosphere. Then, the billets were extruded with different extrusion ratios of 5, 10 and 20 at 673K. The composites were observed by optical microscope and FE-SEM. The mechanical properties were evaluated by Vickers hardness and tensile tests. We succeeded in achieving fully densified and finely extruded rod of Al/CNT composites by hot extrusion process. Observation of micro structures after hot extrusion revealed that CNT aligned along the extrusion direction. Vickers hardness and tensile strength obtained were about twice compared to pure Al.

Mono-sized silicon particles were effectively fabricated by a novel way named pulsated orifice ejection method (POEM). The particles are with very narrow particles size distribution and very small standard deviation of mean particle size. There are two different types spherical silicon particles were found. One consists of many grains mainly in random boundaries. The other consists of two or three grains with only twin orientation relationships, even single crystal in cross-section was also found within this type spherical silicon particles.

Gas release behavior from aluminum and Al 7075 alloy powders during heating in argon was investigated by in-situ gas chromatography. Water vapor, hydrogen, carbon mono-oxide were detected as individual evolution spectra against heating temperature and time. The mechanisms of water and hydrogen evolutions were studied in detail for the determination of effective degassing condition. The adsorbed water and aluminum hydrate on the particle surfaces were considered to be the sources for the released water. Hydrogen peaks were formed from released gases through the reaction of aluminum and magnesium with adsorbed and hydrated water, and from liberated hydrogen that would have been excessively occluded during atomization. For the alloy powder magnesium was found to lower the hydrogen evolution temperature to enhance overall hydrogen release.

International audience; We fabricated a uniformly dispersed and aligned multi-walled carbon nanotube reinforced aluminum matrix (Al–MWCNT) composite with minimal work hardening and without interfacial chemical compounds. In this paper, the direct load-bearing contribution of MWCNTs on the Al–MWCNT composite was investigated in detail for various volume fractions of MWCNTs. For up to 0.6 vol% of MWCNTs, the ultimate tensile strength (UTS) of the Al–MWCNT composite increased with the conservation of the remarkable failure elongation of Al. These UTS values are consistent with shear lag model. We also observed an uncommon multi-wall-type failure of MWCNTs during the hot extrusion process. However, owing to the agglomeration of MWCNTs in the Al matrix, the UTS deviated significantly from the shear lag model and the remarkable failure elongation of Al decreased. The possibility of strengthening, without degrading ductility, was demonstrated by exploiting directly the load-bearing ability of individually and uniformly dispersed aligned MWCNTs.

International audience; The microstructure of graphite flake (GF) reinforced aluminum (Al) matrix (Al–GF) composites was observed in detail. Due to thermal mismatch between Al and GF, an inner structure of GF was damaged in proximity to the Al/GF interface, while the unique bridging of the sticky graphite sheets barely connected the Al matrix and GF. This result suggests that the GF interlaminar strength is weaker than the Al/GF interfacial strength; the GF interlaminar strength is thus the dominant determinant of the thermomechanical and mechanical properties of the Al–GF composite. Whereas the thermal conductivity of the Al–GF composite was consistent with that theoretically predicted, the outstanding thermal expansion coefficient (TEC) of the graphite was not reflected in the produced Al–GF composites. The damaged inner structure of GF in proximity to the Al/GF interface contributes to heat transfer but does not bear the load resulting from thermal stress.

Materials that have strong resistance to both beam impact (or shock-wave) and radiation damage are required for the beam target of an intense accelerator and space applications. Recently, Futakawa et al. found in their experiments that Kolsterising specimens have a stronger resistance to pitting than SS316 CW. A similar effect can be expected for other hardening treatments, and new material development is hopeful. Accordingly, we have started the development of high-performance materials by organizing the project team from KEK, JAEA and universities. In this paper, the scope of the project is introduced. Recent topics involve the development of intergranular crack (IGC)-resistant austenitic stainless-steel, AlN–TiN ceramics and cladding techniques of thin tantalum or CrN film on a tungsten target by means of a molten-salt method and ion-beam-enhanced deposition. New observations on corrosion resistance are presented.

Lanthania (La2O3) and zirconia (ZrO2) powders in ethanol based suspension were mechanochemically treated in a planetary ball mill for 12 hours at 200 rpm, dried and sintered at various temperatures from 400 to 1500. Particles in nanometer sizes are produced after milling. X-ray diffractometry results show the formation of single phase lanthanum zirconate on subsequent heat treatment for 1h at 1500. Phase evolution based on the intensities of the XRD plots and BET surface area analysis indicates three stages of crystallization: below 800, between 800 and ~1100, and above 1100 where reflections of La2Zr2O7 with pyrochlore structure are increased with further heating. Only endothermic energy peaks are observed in the differential thermal analysis (DTA) curve of the milled powders, which could be attributed to the reactions involving dehydroxylation, decarboxylation and complete disintegration of ethanol. This indicates that probably, lanthanum zirconate has grown on sintering at high temperatures from the very fine particles produced by mechanochemical activation during milling. Thermogravimetric analysis has recorded a total weight loss of ~9% from the original weight of the milled powder on sintering at 1500. The values of the surface area of the powders are found to decrease while the crystallite size of La2Zr2O7 are increased with increasing temperature.

Carbon nanotubes (CNT) have superior mechanical properties and high thermal conductivity. For such reasons, the development of CNT-metal matrix composite is gaining wide research attention. In this study, Al/CNT composite was fabricated by powder metallurgy employing the slurry mixing process and Spark Plasma Sintering (SPS) to overcome fabrication problems like agglomeration, which leads to the decrease in thermal conductivity and density.Slurry precursors with homogeneously dispersed CNT were obtained by hetero-aggregation, with optimum amount of ethanol. By sintering these precursors, the composites densified up to more than 99% in relative density. Dispersion and orientation of CNTs were verified by FE-SEM observation of microstructure. The thermal conductivity of the composites decreased with increasing CNT content, and the corresponding thermal anisotropies are indicated. The thermal properties are improved by extending the holding time during sintering.

A pulsated orifice ejection method (POEM) has attained mass-production of monosized spherical micro particles of solder. In this method, the micro droplet melts are emitted from a small orifice by applying both mechanical pulses and constant gas pressure to the melt. This paper reports further development of this method for alternative monosized copper spherical particles with a size in the order of 100 mm. The possibility of the droplet formation was strongly determined by the wettability of orifice material to the melt. Droplets of molten copper could be stably formed at a particularly high contact angle. Using an orifice with the low wettability, monosized copper particles are obtained in a wide range of process parameters such as the rod displacement and gas pressure. Their particle size was also clarified to vary with changes in the two parameters. Especially, the gas pressure may linearly control the particle size from 75 to 120 mm, which is equivalent to 75 to 120% of the orifice diameter. All monosized particles produced by the POEM have an excellent mono-dispersivity less than 2.0 in standard deviation.

A pulsated orifice ejection method (POEM) has attained mass-production of monosized spherical micro particles of solder. In this method, the micro droplet melts are emitted from a small orifice by applying both mechanical pulses and constant gas pressure to the melt. This paper reports further development of this method for alternative monosized copper spherical particles with a size in the order of 100 μm. The possibility of the droplet formation was strongly determined by the wettability of orifice material to the melt. Droplets of molten copper could be stably formed at a particularly high contact angle. Using an orifice with the low wettability, monosized copper particles are obtained in a wide range of process parameters such as the rod displacement and gas pressure. Their particle size was also clarified to vary with changes in the two parameters. Especially, the gas pressure may linearly control the particle size from 75 to 120 μm, which is equivalent to 75 to 120% of the orifice diameter. All monosized particles produced by the POEM have an excellent mono-dispersivity less than 2.0 in standard deviation.

Multiwall carbon nanotube (MWNT) materials are attractive because they possess excellent thermal conductivity and mechanical properties. However, few reports exist that focus on improving the thermal conductivity of MWNT by combining it with a metal matrix. Thus to improve the thermal conductivity, a nickel-matrix composite with MWNT was prepared by slurry mixing process using ethanol as a solvent. Using spark plasma sintering (SPS), MWNT/Nickel nanocomposites were fabricated and the fabrication conditions were investigated. The sintered relative densities of the composites containing up to 5 vol% of MWNT were above 99%. The thermal and electrical behaviors of the MWNT/Nickel composites were determined using the laser flash and van der Pauw methods, respectively, and were found to be anisotropic. The thermal conductivity was found to increase by 10% for the composition with 3 vol% MWNT.

Carbon nanotube (CNT) has excellent feature like low density, high strength, and high thermal conductivity. The metal-based CNT composite is expected as a light and high strength material or the heat radiation material for the application to automobile and aircraft parts, etc. Such that the development of CNT-metal matrix composite is gaining wide research attention. Since CNTs are easy to agglomerate, however, it is difficult to disperse them into a metal matrix homogeneously. To overcome these problems, in this study, CNT-Nickel matrix composite was fabricated by using hetero aggregation and spark plasma sintering method. Slurry precursors with homogeneously dispersed CNT were obtained, with optimum in amount of ethanol. The composites were densified up to more than 99% of relative density by sintering these precursors. Additionally, dispersion and orientation of CNTs were verified by FE-SEM observation of microstructure. The thermal conductivity of the composite was increased by about 10% or less at room temperature. Thermal anisotropy were indicated.

Application of FGM concept for thermal barrier coatings (TBC) provides a superior thermal stress relaxation over homogeneous or duplex coatings. It was demonstrated that FGM TBC have better oxidation resistance and longer lifetime during test conditions. In this work, new FGM TBC system was designed using high-velocity oxygen flame (HVOF) coating process. After coatings optimisation, coating layer was subjected to a hot burner test for thermal fatigue cycling with increasing heat load. It was found that FGM TBC has successfully withstood thermal cycling and prevented visible delamination or transverse cracks. New coating design may give an opportunity to develop a cost-effective FGM TBC system for gas turbine applications.

We estimated the zinc (Zn) and copper (Cu) balance in Japanese farmland soil in 1997. Zinc and Cu uptake by crops amounted to 563 Mg and 108 Mg, respectively, while Zn and Cu doses from chemical fertilizer were 297 Mg and 63 Mg, respectively. Zinc and Cu contents of livestock excreta were estimated to be 2,863 Mg and 713 Mg, and 1,551 Mg and 337 Mg of this was applied to farmland soil. As a result, there was an excess of 1,285 Mg of Zn and 292 Mg of Cu in farmland soil. This excess corresponded to 0.379% of the amount of total Zn and 0.270% of the amount of total Cu in farmland soil. Even if all excess Zn and Cu was accumulated in farmland soil, it would take more than 190 years to reach the permissible upper level of Zn, based on the average Zn concentration in non-polluted farmland soil. However, the promotion of the use of livestock excreta, especially pig excreta that contain high levels of Zn and Cu, may shorten the time required to reach the level. Although there are some guidelines, the recommended...

A bulk SiC/C functionally graded material (FGM) having a compositional gradient from carbon (C) to silicon carbide (SiC) was obtained by powder metallurgy method with SiC, B and amorphous C powders as starting materials. The average graphite ratio of C was 66% higher than ordinary graphite. Compared with CVI and CVD SiC/C FGM and SiC coating, hot-pressed SiC/C FGM has high effective thermal conductivity while the thickness of SiC layer is 1 mm or so. Under cyclic high-temperature heat flow conditions, SiC/C FGM did not suffer cracking and was shown to be superior in resistance to thermal fatigue. The plasma-relevant performance indicated that it has excellent high-temperature erosion resistance.

The objective of this research was to study heat insulation performance and fracture behavior of thermal barrier-type functionally graded material (FGM) coatings under high heat flux. The FGM coatings with thicknesses varying from 0.75 to 2.1 mm were designed and deposited onto a steel substrate by plasma spraying. With the high heat flux of 0.68 MW m−2, the thickest specimen exhibits a high surface temperature of 1690 °C and the corresponding temperature difference between the top surface and the bottom surface of the coating is high up to 760 °C. The results of thermal cycling test with a surface temperature of 1400 °C (during heating) showed that there existed a great difference in fracture location between different specimens. Fracture behavior of the coatings at surface temperatures of 1500, 1600 and 1700 °C was also investigated. The coating thickness and surface temperature were found to influence the number and the length of cracks. The specimen with the coating thickness of 1.1 mm is the most susceptible to local spallation at the top ceramic coat, while the thickest FGM coating is the most susceptible to cracking at the interface close to the bond coat. Heating time also had an effect on cracking behavior. These results provided some necessary information for appropriate design of FGM coatings to sustain higher temperatures and gradients than those in today's applications.

Powder mixtures with nominal compositions of 75 mol% SiC and 25 mol% AlN as well as 50 mol% SiC and 50 mol% AlN were prepared by ball milling for 1-300 h and subsequently sintered to full density by hot isostatic pressing (HIPing) at 1850°C under a pressure of 200 MPa. Microstructures and properties of the HIP-sintered SiC-AlN powder mixtures were investigated with special attention to the effect of ball milling on the formation of SiC-AlN solid solutions. Extensive ball milling facilitated effectively the formation of solid solutions by improvement in mixing homogeneity and pulverization of the SiC and AlN powders. Thermal conductivity of the HIP-sintered SiC-AlN powder mixtures decreased remarkably with ball-milling time, mainly because of the enhanced formation of solid solutions. Mechanical properties-such as strength, fracture toughness, and microhardness-were dependent on the microstructural homogeneity and the grain refinement resulting from the formation of solid solutions.

A photonic crystal is an artificial crystal with a periodic array of dielectric material. Such a crystal possesses a band gap for an electromagnetic wave with wavelengths corresponding to a lattice period. In this study, the photonic crystal with the spherical lattice of hundreds of micrometer-order corresponding to wavelengths of terahertz wave was fabricated by a template method. Monosized spherical copper particles were self-assembled into f.c.c. structure and sintered to form necks between adjacent particles. The array was impregnated with the resin whose dielectric constant was controlled. Subsequently to cure the resin, only the copper particles lattice was etched away by chemical dissolve. The obtained resin-inversed crystals were confirmed to exhibit a photonic stopgap along ‹111› direction by a terahertz wave spectroscopy. The frequency and gap width of measured gaps well agreed with the calculated ones by the plane wave expansion method.

症例は58歳, 男性. 1975年より症候性てんかんのため, 抗てんかん薬による治療を受けており, 最近はフェニトインを服用していた. 2002年6月上旬より悪心・嘔吐, ふらつき感が出現し増悪するため, 当科緊急入院となった. 入院後, 眼振, 複視, 舌のもつれ, 歩行障害, 傾眠傾向が出現したため, フェニトイン中毒を疑った. フェニトインの血中濃度を測定したところ45.8μg/mLと著明に上昇していたため, フェニトイン中毒と診断した. そこで, フェニトインを中止し, 強制利尿, 下剤の投薬を行ったが症状は改善しなかったため, 治療開始8時間後, 活性炭血液灌流療法を施行した. フェニトイン血中濃度は治療前45.6μg/mLから治療後26.0μg/mLに低下し, 速やかに症状は改善した. その後, 後遺症を認めなかったため, 10日後に退院した. 症候性てんかんの患者に発症したフェニトイン中毒について文献的考察を加えて報告する.

Porous NiTi alloy with several different porosities was processed by spark plasma sintering. The compression behavior of the porous NiTi was examined with the aim of using it possibly as a high energy absorbing material. A model for the macroscopic compression behavior of porous shape memory alloy (SMA) is presented in this work, where Eshelby’s inhomogeneous inclusion method is used to predict the effective elastic and superelastic behavior of a porous SMA based on the assumption of stress–strain curve. The analytical results are compared with experimental data for porous NiTi with 13% porosity, resulting in a reasonably good agreement.

Modified Small Punch (MSP) test techniques have been used to evaluate the strength of Mo/PSZ (partially stabilized zirconia) composites from room temperature to 1573 K. The dependence of deformation, strength and fracturebehavior of the composites on temperature, composition and microstructure is discussed in detail. The results show that the high temperature strength, which depends on the composition as well as the microstructure, can be simply measured by the MSP tests. Linear relationship is obtained between the MSP strengths and 4-point bending strengths.

Powders of La 2 O 3 and ZrO 2 in ethanol based suspension were planetary ball milled at 200 rpm for 12 hours, dried and then heat treated at 1500°C for one hour to synthesize single phase of La 2 Zr 2 O 7 which is a very promising thermal barrier coating material. Planetary milling results to particle diminution together with an increase in surface area with increasing milling time as investigated by FE-SEM, particle size analyses and BET method. The formation of single phase La 2 Zr 2 O 7 with pytochlore structure was confirmed by X-ray diffraction and TEM analyses. DSC investigation on the milled powders revealed the dehydroxylation reaction at around 320°C and complete disintegration of ethanol including decarboxylation at around 500°C. The absence of these peaks in the thermal plot for the single phase material confirms its thermal stability at 1500°C sintering temperature.

Single-phase lead lanthanum zirconate titanate (PLZT) solid solution powder was synthesized from the constituent oxides at ambient temperature through a mechanical alloying (MA) process and was then densified to fine-grained ceramics by sintering and hot-pressing. The anomalous photovoltaic effect (APV) and photoinduced strain of the resultant PLZT ceramics were investigated and analyzed in association with the influence of grain size. It was found that a photoinduced voltage up to 6000 V·cm−1 can be obtained as the grain size is reduced to 0.42 μm. This is extremely high and about three times that achievable in normal micrometer-grained PLZT ceramics. The maximum photoinduced strain of the PLZT ceramics with an average grain diameter of 0.54 μm reached 0.01%, which is equivalent to electric-field-induced strain of common piezoelectric materials.

Germanium spherical particles were prepared by pulsed orifice ejection method. The apparatus was divised for ejecting molten droplet from a small orifice by a reciprocating action of a rod given by piezoelectric actuator. Germanium particles with diameter of several hundreds micrometer could be formed by optimizing process parameters of feeder cross-section area, rod position, supplied pressure and rod displacement. The obtained particles were polycrystal and had microstructure derived either from dendritic growth at a high undercooling or lateral growth at a low undercooling. The latter particles exhibited smaller number of grains than the former ones, and these grain boundaries were twin planes. Finally, solidification mechanisms for the particles were estimated.

The ceramic composites consisting of titanium nitride and aluminium nitride were prepared by mechanical alloying (MA) of AlN, Ti and ammonium carbonate. Comparing with conventional way, which used AIN and TiN powders as the initial materials, in this study, nearly full densification can be achieved by hot pressing or by spark plasma sintering at much lower temperatures. XRD analysis indicated that besides AlN and TiN, Al 2 O 3 is also present after sintering. SEM observations showed that the average grain size of the sintered compacts is lower than 0.5 μm. The sample which had been subjected to MA using steel grinding medium for 52 h exhibited Vickers hardness of 18.9 GPa, which is comparable to the value that reported by other researchers.

Powders of La 2 O 3 and ZrO 2 in ethanol based suspension were used as precursor materials for the wet mechanochemical (MC) synthesis of single phase La 2 Zr 2 O 7 , a promising thermal barrier coating (TBC) material. Lanthania powder was first preheated at 1200'C prior to MC treatment in a planetary ball mill at 200, 300 and 400 revolutions per minute (rpm) milling speeds for 12, 18, and 24 hours using zirconia pot and balls. The slurries were then dried at 110°C for 24 hours in an oven followed by heat treatment at 1500°C for 1 hour. X-ray diffraction results showed that single phase La 2 Zr 2 O 7 was produced using 5 mm ball at 200 rpm milling for 12 hours and using 10 mm balls at 400 rpm for 24 hours. Smaller grinding balls and slower milling speed allowed more homogeneous mixing during wet mechanochemical treatment in a 250 mL milling pot. The average particle size of the products is lower than 1.8 μm. The yield of powder is greater than 98%.

The electrical, thermal and mechanical properties of functionally graded materials vary with microstructure and composition. Consequently it is very important to know quantitatively the properties of composites for the design of functionally graded materials. However, few methods of quantitative and theoretical evaluation for material properties on wide compositional range have been established. In this research, a method that estimates the material properties of composites directly from their microstructure assisted with finite element analysis was investigated. As an example of the estimation of material properties, the thermal conductivity of Mo fiber-Cu matrix composites has been evaluated. Calculated results of thermal conductivity are well in agreement with the experimental data measured by using a laser flash apparatus and the smallest deviation is 1.9%. The finite element analysis using a metallographic model is a very accurate method for estimation of composite properties.

Samples of water and suspended solids (SS) collected from the Hinuma river system over one year were analyzed by PIXE (Particle Induced X-ray Emission) to determine elemental concentrations.The average SS concentrations at the 11 sampling sites ranged from 1.4 to 12.7mg·l-1 during ordinary water discharge. The SS concentrations were the highest in the upstream reaches of the Hinuma River, but were lower from the middle to downstream reaches, suggesting that the SS may have settled to the riverbed. All of the SS samples contained relatively high concentrations of Al, Fe, Ca, K and Mg, suggesting that the SS consist of particles from the earth's crust. Variations in elemental ratios to Al of Na, Mg, K, Ca and Cu in the SS among the sampling sites may have been due to differences in geology, land use, drainage from quarries, or brackishness of the water. Moreover the highest Fe: Al ratio was observed at a site where a large microbial mat had developed; the Cu: Al ratio was remarkably high at another site where intensive pig farming was practiced.

Functionally graded metal/ceramic coatings with thicknesses varying from 0.75mm to 2.1mm were designed and deposited onto a steel substrate by plasma spraying. The heat insulation performance of these coatings were studied. It was found that, at a given heat flux, the thicker specimens exhibited higher surface temperature (Ts), greater temperature difference (ΔT) and higher effective thermal conductivity (λeff). The thermal cycling test with a surface temperature of 1400°C (during heating) was also conducted for the study of fracture mode of the specimens. Furthermore, the fracture behavior of the coatings at high surface temperatures between 1500°C and 1700°C was investigated. The coating thickness and surface temperature were found to influence the number and the length of cracks. The results showed that thinner coatings were susceptible to local spallation at the top coat, and while, the thicker FGM coatings were susceptible to cracking at the interface close to the bond coat.

High thermal conductivity and small thermal expansion coefficient are property requirements for heat sink materials, and Cu-Mo composite is an attractive one. Owing to the thermal property of Cu-Mo composite which varies much when the microstructure is changing, the composition and microstructure should be carefully designed to achieve appropriate combination of properties. Consequently it is very important to quantitatively evaluate properties of the composite. In this research, a method that estimates the thermal conductivity of composites directly from their microstructure assisted with Finite Element Analysis (PEA) and Digital Image Based (DIB) technique was investigated. The effective thermal conductivities of rolled anisotropic Cu-Mo composite plates were evaluated parallel to and perpendicular to the rolling direction. The calculated thermal conductivities perpendicular to the rolling direction were compared with experimental data and found they are in good agreement. Hence, the FEA combined with DIB technique is a very helpful method for estimation of effective thermal conductivity of anisotropic composite materials.

The development of myoblasts is regulated by various growth factors as well as by intrinsic muscle-specific transcriptional factors. In this study, we analyzed the roles for STAT3 in the growth and differentiation of myoblasts in terms of cell cycle regulation and interaction with MyoD using C2C12 cells. Here we found that STAT3 inhibited myogenic differentiation induced by low serum or MyoD as efficiently as the Ras/mitogen-activated protein kinase cascade. As for this mechanism, we found that STAT3 not only promoted cell cycle progression through the induction of c-myc but also inhibited MyoD activities through direct interaction. STAT3 inhibited not only DNA binding activities of MyoD but also its transcriptional activities. However, the inhibited transcriptional activities were restored by the supplement of p300/CBP and PCAF, suggesting that STAT3 might deprive MyoD of these transcriptional cofactors. In addition, we found that MyoD inhibited DNA binding activities of STAT3, thereby inhibiting STAT3-dependent cell growth and survival of Ba/F3 cells. These results suggest that the development of muscle cells is regulated by the coordination of cytokine signals and intrinsic transcription factors.

For the development of tantalum-clad tungsten targets for spallation neutron sources, the bonding strength of tantalum–tungsten interface was investigated by means of an easy-to-use and miniaturized small punch (SP) test, in which a punching load is vertically applied to the center of a jointed disk. Cracks initiated and propagated in the tungsten side for all the samples hot-isostatically pressed (HIPed) at temperatures from 1673 to 2073 K, whereas no crack and debonding were observed in the interface, indicating that the jointed interface is strongly bonded. The recrystallization of tungsten occurs and results in its strength reduction, consequently the crack-initiating load decreases with HIPing temperature. The finite element analysis of the measured SP testing results shows that the maximum bonding strength can exceed 1000 MPa. The present study shows that SP test is suitable for the strength evaluation of jointed tantalum–tungsten interfaces.

Promyelocytic leukemia protein PML acts as a tumor suppressor, whereas its chimeric mutant promyelocytic leukemia/retinoic acid receptor alpha (PML/RAR alpha) causes acute promyelocytic leukemia (APL). Because PML has been shown to form transcription-regulatory complexes with various molecules, we speculated that PML and/or PML/RAR alpha might affect signal transducer and activator of transcription 3 (STAT3) activity, which plays a crucial role in granulocyte colony-stimulating factor (G-CSF)-induced growth and survival of myeloid cells. In luciferase assays, PML inhibited STAT3 activity in NIH3T3, 293T, HepG2, and 32D cells. PML formed a complex with STAT3 through B-box and COOH terminal regions in vitro and in vivo, thereby inhibiting its DNA binding activity. Although PML/RAR alpha did not interact with STAT3, it dissociated PML from STAT3 and restored its activity suppressed by PML. To assess the biologic significance of these findings, we introduced PML and PML/RAR alpha into interleukin-3 (IL-3)-dependent Ba/F3 cells expressing the chimeric receptor composed of extracellular domain of G-CSF-R and cytoplasmic domain of gp130, in which gp130-mediated growth is essentially dependent on STAT3 activity. Neither PML nor PML/RAR alpha affected IL-3-dependent growth of these clones. By contrast, gp130-mediated growth was abrogated by PML, whereas it was enhanced by PML/RAR alpha. These results reveal new functions of PML and PML/RAR alpha and suggest that dysregulated STAT3 activity by PML/RAR alpha may participate in the pathogenesis of APL.

Hairy cell leukemia (HCL) is a rare type of chronic B-cell leukemia characterized by the hairy morphology of the leukemia cells. All of 5 HCL samples and an HCL-derived cell line, BNBH-I, showed serrated edges and hairlike projections in May-Grünwald Giemsa stain and protruding actin spikes and lamellipodia in phalloidin stain. These structures were hardly detected on B-cell chronic lymphocytic leukemia (B-CLL) and precursor B-cell acute lymphocytic leukemia (B-ALL) cells. Because Rho guanosine triphosphatases (GTPases) regulate the formation of these structures, we examined the expression levels and activation states of Rho GTPases in HCL cells. RhoA, Rac1, and Cdc42 were overexpressed and constitutively activated in HCL samples and BNBH-I cells but not in B-CLL or precursor B-ALL cells. Next we overexpressed dominant-negative (DN)-RhoA, DN-Rac1, and DN-Cdc42 in BNBH-I. As a result, each DN mutant repressed the growth of BNBH-I cells by more than 50% and inhibited actin spike formation, but only DN-Racl suppressed lamellipodia formation. We also found that enforced expression of constitutively active-RhoA, Rac, or Cdc42 in the proB-cell line Ba/F3 was sufficient to induce actin spike formation, whereas none of these molecules produced lamellipodia. These results indicated that constitutively activated Rho GTPases regulate the growth and unique morphology of HCL cells.

PIXE (Particle Induced X-Ray Emission) 分析法は, ごく微量の試料量を用いた高感度の多元素同時分析が可能である。本研究では, 河川水を分析対象として, PIXE分析における必要な試料量と分析精度, PIXE分析法とICP-AESおよびICP-MS分析法との相互比較, ならびにPIXE分析法の有効性と限界性を明らかにした。PIXE分析法で河川水標準試料の溶存物質中のMg, K, Ca, Cr, Cu, Se, Pbが, 認証値とほぼ一致する結果が得られた。PIXE分析法による茨城県涸沼川流域の河川水から分離した懸濁物質の元素分析では, ほとんどの試料において10元素以上が定量可能であった。PIXE分析法による懸濁物質の測定値と, ICP-AESまたはICP-MS分析法による全分解試料の測定値を比較したところ, Na, Mg, Al, K, Ca, Ti, Mn, Fe, Cuは両者の値に高い相関があった。そして, PIXE分析法による懸濁物質の元素分析は, X線の自己吸収の補正を用いるなどにより, 試料の酸分解操作を行わずに, Na, Mg, Al, Si, S, K, Ca, Ti, Mn, Fe, Cu, Br, Sr, を迅速に同時定量できることが示唆された

The strontium isotope ratio (87Sr / 86Sr) of brown rice (Oryza sativa L.) was determined by multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in order to evaluate the values of 87Sr / 86Sr for use in the estimation of the area of rice production. Sample solutions were prepared from 5 g of rice samples using the acid (HNO3-HClO4-HF) digestion method. Removal of rubidium from the sample solutions was performed using ion-exchange resin (Dowex 50W X8). The Sr isotope ratios were determined with a precision of < 0.01% (RSD, repetitions = 60) by MC-ICP-MS. Typical analysis time for a single sample was about 15 min, reflecting the high sample throughput. The Sr isotope ratios of the Japanese rice samples ranged from 0.706 to 0.709. The Sr isotope ratios of the Chinese and Vietnamese rice samples (0.710 to 0.711) were slightly higher than those of almost all the Japanese samples. Australian rice showed the highest Sr isotope ratio (0.715 to 0.717) among all the rice samples exam...

Thermal fracture behavior of metal/ceramic functionally graded materials (FGMs) was evaluated by a well controlled burner heating method using a H2/O2 combustion flame, which simulated real environment. Partially stabilized zirconia (PSZ)/IN100 FGMs having finely mixed microstructures and PSZ/Inco718 FGMs having rather coarse microstructures were prepared by a slurry dipping and HIP sintering process. Also, three types of functionally graded thermal barrier coatings (TBCs) as well as duplex coatings, each designed to have the same thermal resistance, were fabricated by an air plasma spraying process. The fracture mechanism has been discussed on the basis of the crack morphology, the analysis of acoustic emissions and the variation of effective thermal conductivity. The thermal shock fracture behavior is discussed on PSZ/In100 FGMs and PSZ/Inco718 FGMs, while the cyclic fracture behavior is discussed on plasma sprayed coatings. The cyclic fracture behavior is found to be: orthogonal crack formation on the top surface during cooling, then transverse crack formation in the graded layer during heating, and subsequent growth of transverse cracks and their coalescence which eventually causes the ceramic coat to spall. Compared to duplex coatings, it has been revealed that functionally graded TBCs possess the desirable effect for improvement of spallation life under cyclic thermal loads. The dependence of spallation life on composition profile in functionally graded coatings has been discussed.

4Plasma flows in a 100-kWe-class, steady-state, self-field magnetoplasmadynamic (MPD) thruster were simulated by a plasma flow solver coupled with an electrode sheath model, which enables us to evaluate electrode fall voltages quantitatively. In this paper, influences of the coupling with the electrode sheath model on discharge pattern are discussed as well as dependences of thruster performances on the propellant mass flow rate and the discharge current. By the coupling, it is shown that a thrust is not significantly affected while a discharge voltage is increased attributed to a cathode fall voltage comparable with a potential fall just in the bulk plasma. The thrust and discharge voltage evaluated with the electrode sheath roughly agree with existing experimental results. For an argon mass flow rate of 2.0 g/s and a discharge current of 8 kA, the average cathode fall voltage was estimated to be 7.1 V, which is comparable with the average bulk fall voltage (7.1 V). Thus, it can be said that energy consumption within the cathode sheath is a significant loss factor of the MPD thruster.