Abstract: AlN powders were synthesized by gas-reduction- nitridation of γ-Al2O3 powders using
NH3 and C3H8 as reactant gases. AlN was identified from the products that synthesized at
1100-1400 oC for 120 min in the NH3-C3H8 gas flow, and it was confirmed that AlN can be easily
fabricated by the gas-reduction-nitridation of γ-Al2O3. The products synthesized at 1100oC for
120min contained unreacted γ-Al2O3. By the 27A1 MAS NMR spectra, Al-N bonding in the product
increased with an increase in the nitridation ratio of the tetrahedral AlO4 shoulder which decreased
prior to that of the octahedral AlO6 shoulder. It seems that γ-Al2O3 was preferentially nitrided from
AlO4 rather than AlO6. AlN nano particles were easily converted directly from γ -Al2O3 at a low
temperature because the AlO4 within γ-Al2O3was preferentially nitrided.
Abstract: The influence of reaction temperature on phase evolution of iron oxide hollow
nanoparticles during chemical vapor condensation (CVC) process using iron acetylacetonate was
investigated. X-ray diffraction (XRD) analyses revealed that three iron oxide phases (α-Fe2O3,
γ-Fe2O3, and Fe3O4) and a mixture of β-Fe2O3 and small amount of γ-Fe2O3 were synthesized at
700oC and 900oC, respectively. TEM observation disclosed that the iron oxide particles are almost
composed of hollow structured nanoparticles of 10~20 nm in size and 3~5 nm in shell thickness. This
result implies that reaction temperature determining various reaction parameters plays an important
role for the phase- and structural evolutions of iron oxide hollow nanoparticles. Especially, the
present investigation attempted to explain temperature dependence of the phase evolution of β-Fe2O3
hollow nanoparticles in association with the decomposition of iron acetylacetonate.
Abstract: Nano-sized MWO4 and MMoO4 (M = Ca, Ni) powders, which have scheelite and
wolframite type structure, were successfully synthesized at low temperatures by a modified citrate
complex method assisted by microwave irradiation. The citrate complex precursors were heattreated
at temperatures from 300 to 600 °C for 3 h. Crystallization of the MWO4 and MMoO4
precursors was detected at 400 °C and completed at a temperature of 500 °C. Most of the MWO4
and MMoO4 powders heat-treated between 300 and 600 °C showed primarily spherical and
homogeneous morphology. The average crystallite sizes of MWO4 (M = Ca, Ni) were between 22
and 39 nm, and those for MMoO4 (M = Ca, Ni) were between 19 and 35 nm respectively, showing
an ordinary tendency to grow with temperature.
Abstract: TiO2-SiO2 nanoparticles have been synthesized using a reverse micelle
technique combined with metal alkoxide hydrolysis and condensation. The size of the
particles can be controlled by manipulating the relative rates of the hydrolysis and
condensation reaction of tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TIP)
within the micro-emulsion. The average size of synthesized TiO2-SiO2 nanoparticles was
about in the size range of 20-100 nm. The effects of synthesis parameters, such as the
molar ratio of water to precursor and the molar ratio of water to surfactant, are discussed.
Abstract: Nano-sized metal particles have recently attracted considerable interest owing to their
application potential. Such particles can be synthesized using physical and chemical methods. In
this study, nano-sized noble metals were synthesized through the reaction of metal oxides by
ultrasonic. This means that the chemical reactions which take place under conventional conditions
can be accelerated by ultrasonic cavitations. In general, the chemical effects of ultrasonic
irradiation fall into three areas: homogeneous sonochemical efffects of liquids, heterogeneous
sonochemical effects of liquid-liquid or liquid-solid systems, and sonocatalytic effects. It has been
proposed that liquid-liquid systems are used for the fabrication of nano-metal particles in the past.
In this study, the fabrication of nano-metal particles and supported composites was investigated for
the liquid-solid system from a viewpoint of economy and ecology. By choosing suitable
conditions, it is reasonable to expect that these simple ultrasonic processes can be extended to
obtain nano-sized metal particles. Thus applications by using these reactions were investigated to
prepare the nano-sized metal particle supported materials, and mechanisms were investigated.
Abstract: Au coated γ-Fe2O3 nanoparticles were prepared by the changing of surface charge of Au
and γ-Fe2O3 nanoparticles with pH. Well Au coated γ-Fe2O3 nanocomposite particles developed in
the range between isoelectric point of Au and that of γ-Fe2O3 nanoparticles. Immobilization of
glutathione (GSH), crystalline polypeptide containing mercapto group, was successfully performed
on the well Au coated γ-Fe2O3 nanocomposite particles. Properties of nanoparticles and GSH
immobilized Au/γ-Fe2O3 were characterized by UV-vis, LPA, XRD, and TEM.
Abstract: Accumulative roll-bonding (ARB) process was applied to an oxygen free copper for
improvement of the mechanical properties via ultra grain refinement to nanometer order level.
Two copper sheets 1mm thick, 30mm wide and 300mm long are degreased and wire-brushed for
sound bonding. The sheets are then stacked to each other, and cold-roll-bonded by 50%
reduction rolling. The sheet is then cut to the two pieces of same length and the same procedure
was repeated to the sheets. The ARB process up to eight cycles (an equivalent thickness strain of
6.4) is successfully performed at ambient temperature. TEM observation reveals that ultrafine
grains, hardly containing the dislocation interior, begin to develop at the third cycle, and after
the sixth cycle they cover most of regions of samples. The morphology of ultrafine grains
formed is different from that of aluminum alloys. Tensile strength of the ARB-processed copper
increases with the equivalent strain up to a strain of ~3.2, in which it reached 390 MPa, ~2.1
times higher than the initial value. However, the strength hardly changed at the strain above ~3.2.
Abstract: Via the direct hydrothermal processing using natural rutile as a starting material, long
titanate nanofibers (typically 10-500 μm in length and 20-50 nm in diameter) have been successfully
synthesized in high yield Transmission electron microscopy (TEM), energy dispersive X-ray
spectroscopy (EDS), electron diffraction, and UV-Vis spectroscopy demonstrated that the
as-synthesized nanofibers presumably consisted of sodium hydrogen trititanate ((Na,H)2Ti3O7, e.g.,
Na0.4H1.6Ti3O7) including some hexatitanate-type defects ((Na,H)2Ti6O13). The direct hydrothermal
treatment for natural rutile will be a promising low-cost processing for 1-D nanomaterials, which can
act not only as the reaction step but also as the purification.
Abstract: In this study, the synthesis of nanotubular titanate was attempted though heat-treatment
in an oil bath (non-hydrothermal treatment), heat-treatment with stirring in an oil bath
(non-hydrothermal treatment), or hydrothermal treatment for metal Ti in NaOH aqueous solution
systems. Obtained products were characterized by various methods, such as X-ray diffraction
(XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD
results suggested that products obtained by both hydrothermal treatment and heat-treatment in an oil
bath with and without stirring could be identified as H2Ti4O9H2O. From TEM observations,
however, various morphologies for products obtained by these treatments were confirmed.
Therefore, it was considered that morphologies of these products strongly depended on synthesis
Abstract: We have investigated a synthesis of metal (Nb, V, Cr, Mn, Co) -doped titania nanotubes
using a solution chemical processing in order to control optical and electrical properties. Titania
nanotubes doped with a small amount of cations up to 1 wt% exhibited similar morphology and
XRD pattern as the pure titania nanotubes, however, color of nanotubes was changed depending on
the dopants. It was found that Cr, Mn and Co doped titania nanotubes formed new absorption bands
in UV spectra. On the other hand, electrical resistivity of doped titania nanotubes was lower than
that of pure titania nanotubes.