Marked particle size and support effect of Pd catalysts upon the direct decomposition of nitric oxide

The catalytic behavior of beryllia-supported Pd catalyst for the direct decomposition of NO was compared with that of silica supported one. The TOF of NO decomposition was one order of magnitude larger in the case of Pd/BeO. Over Pd/SiO₂, the TOF was increased with the increase of the Pd particle size. On the contrary, over Pd/BeO smaller Pd particles exhibited higher TOF for NO decomposition suggesting some strong electronic or structural interaction between Pd and beryllia. TPD spectra of NO(a) over reduced catalysts indicated that NO was adsorbed on Pd/SiO₂ more strongly than on Pd/BeO, and dissociation of NO(a) was easier on the former catalyst. FT-IR spectra of adsorbed NO at room temperature followed by the evacuation at elevated temperatures confirmed this. TPD spectra of O₂ desorbed from oxidized surface indicated that adsorption strength of O(a) is one of the most important factors to determine the catalytic activity of NO decomposition over supported Pd catalysts.     

Mechanism of formation of C2-oxygenated compounds from CO + H2 reaction over SiO2-supported Rh catalysts

The mechanism of acetaldehyde and ethanol formation from the CO + H₂ reaction below atmospheric pressure has been investigated by combining infrared spectroscopic measurement and ¹³CO and C¹⁸O isotopic tracer studies with reaction kinetics. The rates of acetaldehyde and ethanol formation are markedly dependent on the nature of metal precursors employed. The addition of sodium cations depresses the total catalytic activity, while the selectivity for ethanol is increased by the addition of manganese cations. From the behavior of surface species under reaction conditions, it is concluded that acetaldehyde is formed through the following two steps: (i) CO insertion into C₁ species which are reaction intermediates for not only hydrocarbons but also for the methyl group in acetaldehyde, and (ii) subsequent formation of acetate ions whose one oxygen atom is supplied from the support, finally producing acetaldehyde. Differences in ¹⁸O distribution in acetaldehyde and ethanol during the C¹⁸O + H₂ reaction indicate that ethanol is not produced via direct hydrogenation of acetaldehyde.     

Development of a 275-kV liquid cooling-type gas-insulated transformer

Construction of 275-kV and 500-kV substations in densely populated areas is thought to be necessary in the future to maintain a stable supply of electricity. The use of gas-insulated transformers is now considered for substations because such transformers are non-flammable and nonexplosive. Since the completion of the 77-kV gas-insulated transformer in 1979, we have continued research to develop gas-insulated transformers applicable to a higher voltage level up to 500 kV. As the results of the research, 275-kV, 300-MVA a liquid cooling-type gas-insulated transformer has been developed.     

Computer-controlled microcirculatory support system for endothelial cell culture and shearing

Endothelial cells (ECs) lining the inner lumen of blood vessels are continuously subjected to hemodynamic shear stress, which is known to modify EC morphology and biological activity. This paper describes a self-contained microcirculatory EC culture system that efficiently studies such effects of shear stress on EC alignment and elongation in vitro. The culture system is composed of elastomeric microfluidic cell shearing chambers interfaced with computer-controlled movement of piezoelectric pins on a refreshable Braille display. The flow rate is varied by design of channels that allow for movement of different volumes of fluid per variable-speed pump stroke. The integrated microfluidic valving and pumping system allowed primary EC seeding and differential shearing in multiple compartments to be performed on a single chip. The microfluidic flows caused ECs to align and elongate significantly in the direction of flow according to their exposed levels of shear stress. This microfluidic system overcomes the small flow rates and the inefficiencies of previously described microfluidic and macroscopic systems respectively to conveniently perform parallel studies of EC response to shear stress.     

Development of a frequency-detuned interferometer as a prototype experiment for next-generation gravitational-wave detectors

We report on our prototype experiment that uses a 4-m detuned resonant sideband extraction interferometer with suspended mirrors, which has almost the same configuration as the next-generation, gravitational-wave detectors. We have developed a new control scheme and have succeeded in the operation of such an interferometer with suspended mirrors for the first time ever as far as we know. We believe that this is the first such instrument that can see the radiation pressure signal enhancement, which can improve the sensitivity of next-generation gravitational-wave detectors.     

Photo-induced electron transfer of a chlorophyll—liquid crystal electrode to water

A platinum plate was coated with a thin layer of chlorophyll and liquid crystal in order to make it photo-excitable. The chlorophyll—liquid crystal electrode immersed in water was found to shift its electrode potential to a more positive value on light irradiation. Furthermore light irradiation increased cathodic current. Liquid crystals such as N-(p-methoxybenzylidene)-p′-butylaniline markedly enhanced a photo-response in electrode potential and current. A prominent photo-response of the electrode appeared in an acidic solution around pH 4. A possibility of a direct electron transfer from a photo-excited chlorophyll—liquid crystal electrode to water, ie, photo-decomposition of water, is suggested.