a-Si alloy three-stacked solar cells with high stabilized-efficiency

a-Si alloy three-stacked solar cells have been studied to improve the stabilized efficiency of a-Si: H based solar cells. Based on the analysis by the individual characterization method of the component cells in stacked type cells, the a-Si :H middle cell was replaced with an a-SiGe :H cell. Furthermore, the optical confinement technology was improved to obtain a high-output current with thin i-layer thickness in the a-SiGe :H bottom cell. By this device design, the initial conversion efficiency was improved up to 12.4% and more than a 10% stabilized efficiency was obtained in a-SiC :H/a-SiGe :H/a-SiGe :H three-stacked cells. These cell characteristics were confirmed by measurements at the JQA Organization (the former JMI Institute).     

Catalytic decomposition of HCFC22 (CHClF2)

The catalytic decomposition of CHClF₂ was studied over various acidic metal oxides in a fixed-bed reactor. The Cr₂O₃ZrO₂ exhibited the highest activity. The presence of water vapor in the reaction system suppresses the transformation of oxides to fluorides, progresses the formation of CO₂, and it improves the catalysts life.     

Hydrothermal upgrading of wood biomass: Influence of the addition of K2CO3 and cellulose/lignin ratio

The hydrothermal treatment of two different wood biomass samples such as cherry (hard wood) and cypress (soft wood), whose composition is different i.e. lignin, cellulose and hemicellulose were performed at 280 °C for 15 min with aq. K₂CO₃ with different concentrations (0–1 M). The soft wood biomass contains higher lignin content than hard wood biomass. The cellulose rich cherry wood biomass produced higher proportion of acetic acid than cypress. The lignin rich cypress produced the hydrocarbons with major portion of phenolic hydrocarbons and derivatives than cherry. The total oil yields from both cherry and cypress wood biomass produced 50 wt% of liquid hydrocarbons at 280 °C for 15 min with 0.5 M K₂CO₃ solution. The volatility distribution of liquid hydrocarbons showed the characteristic features of soft and hard wood biomasses.     

Redox properties of CeO2 and Pt-Rh/CeO2 studied by TAP method

Redox properties of CeO₂ and Pt-Rh/CeO₂ were studied by temporal analysis of products (TAP) method using alternative pulses of CO and O₂. A portion of pulsed CO was oxidized to CO₂ and a portion of CO was adsorbed on the surface. Pulsing ¹⁸O₂ onto the catalyst which has surface species derived from CO, evolved CO₂ contained no ¹⁸O suggesting that the surface species will be carbonate ions.     

Effect of platelet-activating factor on lipoprotein lipase and blood lipids

We investigated the effect of platelet-activating factor (PAF) and of the PAF specific antagonist CV-6209 on plasma lipid metabolism, and particularly on post-heparin plasma lipolytic activity in male Wistar rats. Lipoprotein lipase (LPL) activity was enhanced by intravenous injection of PAF before intravenous injection of heparin when the PAF dose was low (0.2 μg/kg). PAF activated hepatic triacylglycerol lipase (HTGL) activity dose-dependently. Plasma triacylglycerols (TG) significantly decreased with the activation of LPL and/or HTGL. Plasma total cholesterol (TC) and phospholipid (PL) levels decreased at a low dose of PAF (0.2 μg/kg), but increased when higher doses were used. The PAF antagonist CV-6209 partially reversed the PAF induced effects on HTGL, TC and PL. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Characterization of the Advanced Satellite for Cosmology and Astrophysics x-ray telescope: preflight calibration and ray tracing

The x-ray properties of multinested thin-foil mirror x-ray telescopes (XRT's) on board ASCA, the Advanced Satellite for Cosmology and Astrophysics, were fully evaluated with an x-ray pencil beam.Scanning over the telescope aperture of 35 cm in diameter with an x-ray pencil beam, we found the effective area of a set of XRT's to be 325, 200, and 113 cm(2) at energies of 1.5, 4.5, and 8.0 keV, respectively. We derive the point-spread functions (PSF's) of the XRT's by measuring the image profile at the focal plane with an x-ray CCD. The PSF is found to exhibit a sharp core concentrated within 30 arcsec and a broad wing extended to 3 arcmin in half-power diameter. We also evaluate the contribution of stray light, which is caused by the single reflection of x rays by primary or secondary mirrors and by the backside reflection of the mirrors. To obtain the characteristics of the XRT in the energy region of 0.5-10.0 keV, incorporated with the measurements at discrete energies, we develop a ray-tracing method with the telescope design parameter, the PSF, and optical constants. In particular, we obtain the optical constants around the gold-atom M shell (Au-M) absorption-edge energies by measuring the reflectivity of our mirror sample, with monochromatized x-rays in the energy range of 2.0-3.5 keV from synchrotron radiation. Taking into account the PSF's and optical constants, we find that our ray-tracing program can reproduce all these XRT performances.     

Fabrication of particle-free thin films by laser ablation combined with an electron beam

Particle-free silicon and nickel thin films were successfully fabricated by laser-ablating a melted section of their target surface, which gives a high evaporation pressure at the melting point. The influence of direct evaporation from a melted target was reduced negligibly by melting the target only locally with a focused electron beam (e-beam) and increasing the laser frequency. The silicon films fabricated by the present method, pulse laser deposition of a partially molten target, were able to firmly adhere to the substrates and withstood steel needle scratching, unlike e-beam-evaporated films.     

Decomposition of CCl2F2 over metal sulfate catalysts

Activity for hydrolysis of CCl₂F₂ (CFC12) on various metal sulfate was investigated. Zr(SO₄)₂ was found to be the most active while FeSO₄, Cr₂(SO₄)₃, Al₂(SO₄)₃, La₂(SO₄)₃ and Ce₂(SO₄)₃ had intermediate activity. MnSO₄, CoSO₄, and MgSO₄ showed low activity and SrSO₄, CaSO₄, and BaSO₄ had even less activity. The major carbon containing product was CO₂ and small amount of CClF₃ and CO were formed over several sulfates. The crystal structure of the sulfates was stable during decomposition of CCl₂F₂, and the conversion reached a steady state after initial decrease at 275 °C over Zr(SO₄)₂ catalyst. The concentration of surface hydroxyl was larger than that over AlPO₄-based catalysts and a reaction mechanism similar to that over AlPO₄-based catalysts was proposed.