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Hybrid collector which produces both electric and thermal energy is very effective system for heightening efficiency of solar energy collector. In order to obtain the fundamental characteristics of these systems, two liquid type flat plate thermal collectors with selective surface have been modified by attaching 3'' diameter silicon solar cells. The measured cell array efficiencies were 8.84% and 9.20% at 28°C, AM 1.15. The maximum thermal efficiencies of these hybrid systems were 72% and 77% using water as coolant.

Steam reforming of glycerin on Ni-loaded catalyst was performed using a ZrO 2 -based support material. The addition of CaO to ZrO 2 improved the catalyst performance, and NiO/CaO-ZrO 2 afforded glycerin conversion of 88.9% with an H 2 yield of 75.3% at 600°C. Carbon formation decreased from 4.2 to 2.0% with CaOadded catalyst. Solid solution was formed with the addition of CaO to ZrO 2 , and it exhibited basic characteristics. Further reduction of carbon formation during the reforming reaction was achieved by using a quaternary complex oxide catalyst NiO-CeO 2 /CaO-ZrO 2 , where glycerin conversion of 96.1% and a H 2 yield of 83.7% were achieved with carbon formation of 0.7% at 600°C.

Amounts of D and H atoms, produced by y-radiolysis of D2-n-H2( 1 mol %) mixtures, were measured at 4.2 or 1.9 K by ESR. The amounts of D atoms decay upon storage of the irradiated sample at 4.2 K up to 114 h, while those of H atoms are nearly constant. The results were interpreted in terms of competition of a tunneling reaction n-H2 + D -H + HD with combination reactions of D and H atoms. Similar decay behaviors of D and H atoms were also observed in D2-pH2(1 mol 96) mixtures at 4.2 K and D2-n-Hz( 1 mol %) mixtures at 4.5 K. The rate constant for the tunneling reaction n-H2 + D + H + HD was estimated from a kinetic treatment of the decay behavior. It was found that the rate constant is expressed by two ranges of values: 2.7 X 10-'-4.9 X 10-' cm3 mol-' S-I and 3.9 X 10-4-2.6 X lC3 cm3 mol-' s-'. The different values of the rate anstant arc related probably to internal rearrangements of reactive spbcies in solid hydrogen at ultralow temperature.The experimental rate constant for the tunneling reaction n-Hz + D -H + HD was compared with the theoretical ones reported previously.

The significant isotope effect on hydrogen elimination reaction from 2,3-dimethylbutane (h-DMB) cations was studied by ESR at 77 K. When a h-DMB-SFa(0.6 mol %I) mixture is y-irradiated at 70 K, h-DMB+ ions in addition to h-DMB radicals are produced. When the irradiated mixture is stored at 77 K for 10 min, tetramethylethylene (TME) cations are produced by HZ elimination from h-DMB+ ions. The rate constant for the HZ elimination reaction was measured as 1.1 x s-l at 77 K. When a 2,3-dimethylbutane-2,3-d~ (d-DMB)-SF6 (0.6 mol%) mixture is y-irradiated at 70 K and then stored at 77 K, TME+ ions are scarcely produced upon the storage of the irradiated mixture at 77 K even for 5 days. The rate constant for the DZ elimination reaction from d-DMB+ ions was measured as 6.5 x s-l, which is much smaller than the rate constant for the HZ elimination reaction. The significant isotope effect on the reactions was explained in terms of a model of the tunneling elimination of a hydrogen molecule from a DMB+ ion.