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ZnS shows high photocatalytic activity, nevertheless the operating wavelength is limited to less than 330 nm. On the other hand, CdS can be used at wavelength up to 512 nm. However, CdS requires Pt as supporting catalyst. We have synthesized Pt-free ZnxCd1-xS particles with x varying between 0 and 1 by co-precipitation method and evaluated their photocatalytic activities. The highest photocatalytic activity was recorded for Zn0.67Cd0.33S particles. Then, ZnxCd1-xS solid solution films were prepared using the above particles by dip-coating method and their photocatalytic activities were evaluated. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Cadmium Sulfide semiconductor has comparatively small band gap and act as photocatalyst under irradiation of visible light. For practical use, it is convenient to fix the photocatalyst on a substrate as a thin film. In this study, we prepared CdS thin film on Ti substrate by Chemical Bath Deposition (CBD). To improve photocatalytic activity, CdS film was annealed and optimum thickness was investigated. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Mn0.67Zn0.33Fe2O4 nanoparticles with size ranging from 20 to 80 nm have been synthesized using the modified oxidation method. The Curie temperatures for all the samples are found to be within 630 ± 5 K suggesting that there is no size-dependent cation distribution. Mössbauer studies on the synthesized nanoparticles suggest that the critical particle size limit for superparamagnetism to be about 25 nm at 293 K. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The synthesis of Cu doped ZnS particles by ion-exchange method and the influence on workable wavelength of light is reported. The workable wavelength of Cu doped ZnS was extended from the same of ZnS (310 nm). The photocatalytic activity of Cu doped ZnS was measured by hydrogen generation experiment using solar simulator and the highest apparent quantum yield was about 11% given from 1% Cu doped ZnS. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Very fine diamond was synthesized under hydrothermal conditions, with new bond formation among diamond particles, in 10M-NaOH solution at 573K, 1GPa, for 24 hours. This new bonding material is formed by carbonization, from chlorinated hydrocarbon such as dichloromethane and 1,1,1-trichloroethane, under alkaline hydrothermal conditions. The carbonized material forms a new bond between diamond particles by the release of hydrogen-chloride using a hydrated diamond powder particle as the starting material. With pellet of compacted diamond, the platy materials were produced. These materials were diamond by micro-XRD analysis. New growth materials between compacted diamonds, and each diamond particles were bonded. Therefore, it is possible that compacted diamonds is sintered by carbon-bonds under hydrothermal synthesis. Hydrothermal hot-pressing is technic that materials as glass, calcium silicate and calcium carbonate is solidified. Compacted materials is deformed under hydrothermal conditions, and materials is solidified strongly by alterative materials. This technic can be applied to diamond sintering. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotube (SWCNT)/SiC composites were successfully prepared by direct thermal decomposition of polycarbosilane (PCS) precursor. The SWCNT/SiC composites were prepared by the hot-pressing the SWCNTs-PCS (7:3 mass%) mixture at temperatures of 1000, 1400 and 1800°C under a pressure of 120 MPa. The effects of SiC synthesis and processing temperatures on the mechanical properties of the resultant composites were investigated by comparing the experimental data obtained from the SWCNT/SiC composites and the binder-free SWCNT solids. The XRD and TEM-EDS analyses revealed that the β-SiC was successfully prepared through direct thermal decomposition of PCS precursor. The specific modulus and strength of the SWCNT/SiC composites were always about 8 GPa/Mg/m3 and 20 MPa/Mg/m3 higher than those of the binder-free SWCNT solid under identical processing temperatures. Such remarkable stiffening and strengthening by SiC synthesis may be due to the load-transfer efficiency of SWCNTs in the SWCNT/SiC composites. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Binder-free macroscopic single-walled carbon nanotube (SWCNT) solids were prepared by the hot-pressing and the spark plasma sintering (SPS) of purified SWCNTs at temperatures of 1000, 1400 and 1800°C under a pressure of 120 MPa. The effects of processing conditions of the SWCNT solids on mechanical properties and microstructures were investigated. The SPS method was useful to increase the Young’s modulus and fracture strength of the SWCNT solid with respect to the hot-pressing method. The mechanical properties of the SWCNT solids prepared by SPS were always higher than those of the SWCNT solids prepared by hot-pressing under the identical processing temperature. The maximum value for the average Young’s modulus and fracture strength were 25.1 GPa and 106.8 MPa, respectively. TEM observation revealed that the high temperature treatment has converted some part of the SWCNTs into graphite-like materials and the rest of the SWCNTs remained buried into the above structure. The mechanical properties of the SWCNT solids were increased with the increasing processing temperature, reflecting probably the improvement of interfacial strength between SWCNTs and graphite-like materials. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Single walled carbon nanotubes (SWCNTs) prepared by a contact-arc-discharge followed by a hydrothermal purification are analyzed in the mat-form samples with the use of UHV scanning tunneling microscopy and spectroscopy (STM/STS). The characteristic electronic states of individual tubes in a bundle are found to be specified to the bundle. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Mechanical strength of a nanotube bundle has been measured by using quartz glass enclosed-purified SWNTs as the specimen. These specimens were prepared by fast stretching quartz glass tube that contained purified nanotube bundles, at temperatures ranging from 900 to 1490 degrees Centigrade. The maximum average critical load was 42.3 kg/mm[sup 2] for the specimen prepared at 900 degrees Centrigrade. However, at temperatures higher than 900 degrees Centrigrade, the critical load value decreased and became almost equal to that of quartz glass at 1490 degrees Centigrade. It was believed that the decrease in the critical laod value at temperatures higher than 900 degrees Centigrade was due to the partial conversion of nanotubes into amorphous carbon. Since the cross-sectional area used in arriving at the critical load value was that of nanotube and the quartz glass, the cross-sectional area ratio of the quartz to that of the nanotube suggested that the mechanical strength of nanotube would be two orders of magnitude higher than the value reported here. [ABSTRACT FROM AUTHOR]

This paper describes the results of the synthesis of SWNTs in weak and strong DC magnetic fields. In weak magnetic fields with the maximum intensity of 0.5 T, SWNTs were synthesized only when the applied field was parallel to the current direction. These samples consisted of tubes with a diameter as small as about 0.9 nm. Furthermore, the metal particles were smaller compared to zero field case. On the other hand, at strong magnetic fields with the maximum intensity of 2 T, the yield decreased with increasing magnetic field strengths for the arc discharge current of 70 A. This was believed due to forced convection caused by the temperature rise in the anode resulting from higher current densities due to Lorentz force acting on charged particles non-parallel to the magnetic field direction. [ABSTRACT FROM AUTHOR]

In our earlier report, we have already proposed a novel purification method to obtain highly purified SWNTs. Considering the use of SWNTs for the industrial applications, automation of the proposed purification method is required to supply large quantifies of purified SWNTs. In this study, we designed the device to automate the purification process. [ABSTRACT FROM AUTHOR]