Development of both-side junction silicon space solar cells

This paper reports the recent results of improving the radiation hardness of silicon solar cells, which is SHARP and NASDA's project since 1998 (Tonomura et al., Second World Conference on Photovoltaic Solar Energy, 1998, pp. 3511–3514). Newly developed 2×2 cm² Si solar cells with ultrathin substrates and both-side junction (BJ) structure showed 72.0 mW (13.3% efficiency) maximum output power at AM0, 28°C after 1 MeV electron irradiation up to 1×10¹⁵ e/cm² and the best cell showed 72.5 mW (13.4%) maximum output power. These solar cells have p–n junctions at both front and rear surfaces and showed less radiation degradation and better remaining factor than previous solar cells.     

Influence of primary structure on thermal oxidative degradation of polypropylene impact copolymer

Summary Thermal oxidative degradation was carried out using four kinds of polypropylene impact copolymers, and the relationship between primary structure and degradation behavior was investigated by the results of ¹³C-NMR, TEM, GPC and the determination of hydroperoxide value (HPO) and number of chain scission (NCS). The degradation behavior mainly depended on the ethylene content and on the tacticity. The thermal degradation was found to be controllable by the primary structure.     

电子纸的过去、现在和未来

电子纸显示技术已经在越来越多的产品和设备上得到应用。从这项技术的现状出发,分析了阻碍其发展的因素,并对其前景作出了展望。     

Phase Diagram of the BaO(BaCO3)-CaO-CuO System

The phase diagram of the BaO(BaCO₃)-CaO-CuO system, especially in the barium-rich region at 900°C in air, was studied. Two new different oxycarbonates were observed: Ba₈Ca_16/15Cu_64/15O_11.20(CO₃)_2.66and a solid-solution series with a chemical composition of Ba₂Ca _{x + y} Cu_{1+( x /2)- y} O_2+delta(CO₃)_{1- z} (where 0 ≤ to x ≤ to 2/39 and 0 ≤ to y ≤ to 16 x /5). The oxycarbonate solid solution was formed in a region of the compositional triangle Ba:Ca:Cu (in moles) = (2:0:1)-(39:1:20)-(65:7:28). The solid-solution structure had P 4/ mmm symmetry, with lattice parameters a similar/congruent a _pand c similar/congruent 2 a _p, where a _prepresents the perovskite cell. The Ba₈Ca_16/15Cu_64/15O_11.20(CO₃)_2.66compound, which had Pm 3 m symmetry with a lattice parameter a = 0.8116(2) nm, had no chemical-solubility range.     

Oil-water interfacial activation of lipase for interesterification of triglyceride and fatty acid

Lipase usually has little interesterification activity in organic solvents, probably owing to the absence of an oil-water interface. Lipases were processed in a two-phase hydrocarbon-water system that had an oil-water interface. Crude lipase (from Rhizopus japonicus) in a buffer and a small volume of aliphatic hydrocarbon as an oil phase were mixed and then lyophilized to remove the aqueous and oil phases. The interfacially processed lipase has a remarkable interesterification activity in n-hexane compared to crude native lipases. We postulate that this activation is caused by the oil-water interface, i.e., the interface between hydrocarbon and water makes the lipase lid open and enables the lipase to work effectively in n-hexane. Several different hydrocarbons were investigated as an oil phase, and n-tetradecane was found to be the best for interesterification. Activated lipase was successfully inactivated in a water suspension without an oil-water interface, and the inactivated lipase could be reactivated. We demonstrated that the oil (hydrocarbon)-water interface induced reversible activation to lipase for interesterification. This work was presented at the Biocatalysis Symposium in April 2000, held at the 91st Annual Meeting and Expo of the American Oil Chemists’ Society, San Diego, CA     

Equal-channel angular pressing of commercial aluminum alloys: Grain refinement, thermal stability and tensile properties

Using equal-channel angular (ECA) pressing at room temperature, the grain sizes of six different commercial aluminum-based alloys (1100, 2024, 3004, 5083, 6061, and 7075) were reduced to within the submicrometer range. These grains were reasonably stable up to annealing temperatures of ∼200 °C and the submicrometer grains were retained in the 2024 and 7075 alloys to annealing temperatures of 300 °C. Tensile testing after ECA pressing through a single pass, equivalent to the introduction of a strain of ∼1, showed there is a significant increase in the values of the 0.2 pct proof stress and the ultimate tensile stress (UTS) for each alloy with a corresponding reduction in the elongations to failure. It is demonstrated that the magnitudes of these stresses scale with the square root of the Mg content in each alloy. Similar values for the proof stresses and the UTS were attained at the same equivalent strains in samples subjected to cold rolling, but the elongations to failure were higher after ECA pressing to equivalent strains >1 because of the introduction of a very small grain size. Detailed results for the 1100 and 3004 alloys show good agreement with the standard Hall-Petch relationship.     

A study of high-rate shearing of commercially pure aluminum sheet

The effect of shearing speed on the quality of shape and edge-face of the sheared-off products is studied. The tested material is a commercially pure aluminum. The maximum shearing speed is 10 m/s. It is evidenced that the shape quality of the sheared-off parts is better when a smaller clearance and a higher rate of shearing are applied. A thin ring of almost complete rectangular cross-section, i.e. 1.5 mm in width and 10 mm in height, whose edge-face is glossy, is successfully produced by the high-rate shearing process using a constraint tool set at the outer periphery of the sheet blank. It is demonstrated clearly by the pictures of microstructure that the material flow is concentrated within a very narrow band, showing even a recrystallized structure. A theoretical analysis proves that the band is the so-called adiabatic shear band (ASB), and that even melting of material takes place within it. In the shearing process, first an ASB evolves, followed by melting in the early stage of shearing. The major stroke of the punch is occupied by an easy simple shearing in a melted state.     

Detection of Phase Separation by FTIR in a Liquid-Crystal-Display Substrate Aluminoborosilicate Glass

The effect of heat treatment on the Fourier transform infrared spectrometry (FTIR) reflection peak position of the Si–O structural band near 1087 cm⁻¹ of a liquid-crystal-display substrate glass was investigated. The FTIR peak position shifted more slowly with heat-treatment time, and to a greater extent than expected, for the fictive temperature change. The isochronal shift of the FTIR peak as a function of the heat-treatment temperature exhibited a good correlation with the change of chemical durability in an HCl solution, suggesting that the infrared peak shift was the result of the phase separation induced by the heat treatment. The separated phase, with spherical particles ∼50 nm in diameter, was observed by scanning electron microscopy in a glass sample heat-treated at 750°C for 2500 h. The FTIR peak shift measurement appears to be a sensitive method for detecting the early stage of the glass-in-glass phase separation for borosilicate glasses.