Trimethylamine-sensing mechanism of TiO2-based sensors 2. Effects of catalytic activity of TiO2-based specimens on their trimethylamine-sensing properties

The effects of metal additives on the catalytic of TiO₂ for trimethylamine (TMA) oxidation have been investigated in relation to their TMA-sensing properties. The catalytic activity is more or less enhanced by adding a small amount of Ru, In or Au, the behaviour being in good agreement with the fact that these metals are effective in promoting the TMA sensitivity. In contrast, it is found that too great an enhancement in the catalytic activity induced by the addition of Pd, Pt or Rh results in deterioration of the sensitivity. Referring to the relationship between the catalytic activity and the TMA-sensing property, a possible mechanism is discussed.     

Fracture mechanical properties and neutron irradiation effects of fuel compacts for the HTTR

To simulate the nuclear fuel for High Temperature Engineering Testing Reactor (HTTR), fuel compact models using SiC-kernel coated particles instead of UO₂-kernel coated particles were prepared under the same conditions as those for the real fuel compact. The mechanical and fracture mechanics properties were studied at room temperature. The thermal shock resistance and fracture toughness for thermal stresses of the fuel compact were experimentally assessed by means of arc discharge heating applied at a central area of the disk specimens. These model specimens were then neutron irradiated in the Japan Material Testing Reactor (JMTR) for fluences up to 1.7 × 10²¹n/cm² (E ·> 29 fJ) at 900°C ± 50°C. The effects of irradiation on a series of fracture mechanical properties were evaluated and compared with the cases of graphite IG-110 used as the core materials in the HTTR.     

Characterization of long-periodic layered structures by X-ray diffraction II: Lattice distortion of Langmuir-Blodgett films of lead stearate

X-ray 00l reflections from three kinds of 25-layer Langmuir-Blodgett films of lead stearate were measured, using a high resolution reflection Kratky camera system. The accurate thicknesses of a bilayer were evaluated by the modified Bragg law. According to the microstrain, the paracrystalline and the Wilson models, line breadths of the reflections were separated into broadening due to crystallite size and lattice distortion. The crystallite sizes thus obtained agree well with those calculated from the thickness and number of bilayers. Regardless of which distorion model is used, gaussian profiles always give a larger lattice distortion than Cauchy profiles. To describe the lattice distortion of the present specimens, the microstrain and the Wilson models are more favourable than the paracrystalline model. The lattice distortion has been proven to be very sensitive to preparation conditions such as surface pressure and surface treatment of the substrate.     

Performance of Pr-doped fluoride fibre amplifier for multichannel AM-VSB transmission

The system performance of a Pr-doped fluoride fibre amplifier was examined for multichannel AM-VSB video signal transmission for the first time. For a CNR of 51 dB, a loss budget of 15.1 dB was obtained with the amplifier, and for a CNR of 46 dB, the loss budget was expanded to 20.1 dB.<>     

Alpha particle emission from platinum and its influence on DRAM operation

Ferroelectrics such as SrTiO/sub 3/ have been studied as DRAM capacitor insulators. Platinum is commonly used as their electrode material. However, platinum contains the isotope Pt/sup 190/, emitting alpha particles which cause soft errors. The authors measured the alpha particle emissivity of platinum coated silicon wafers. The resultant emissivity is consistent with the calculation. The impact on DRAM operation was estimated.<>     

Coal gasification using a molten iron bath

A coal gasification process using a molten iron bath as reactor has been developed by Sumitomo Metals. Pulverized coal is blown onto this molten iron together with oxygen and steam as gasification agents. Tests using a pilot plant having a capacity of 60 t (coal) day^?1, has shown that a sulphur-free carbon monoxide and hydrogen-rich gas can be generated at high coal conversion efficiency.     

Pleasantness-unpleasantness of environmental sounds and gender difference in evaluation

The present experiment examined emotional evaluation of 40 environmental sounds which were presented to 388 college students in a lecture room. Students were required to rate pleasantness-unpleasantness, to identify the sounds, and to rate their confidence about their identifications. Analysis showed that the pleasant sounds were natural and musical sounds and that the unpleasant sounds were sounds of a belch, of a dentist's drill, and of scratching on a blackboard. It is interesting that for pleasant sounds confidence was always high, which suggested that emotional evaluation of the environmental sounds was closely related to the confidence of observers in their identifications of the sounds. Gender differences were noted on the ratings on pleasantness-unpleasantness of environmental sounds, that is, women evaluated the pleasant sounds as more pleasant than men, and men evaluated the unpleasant sounds as not so unpleasant as did women.