We develop a dynamic structural model of consumers' choices and producers' pricing in an oligopolistic market for newly introduced durable products with network externalities. The model is then applied to empirically analyze the de facto standardization of the VHS format in the U.S. home VCR market during 1981-1988. We find: (i) the network advantage of VHS explains at least 70.3% to 86.8% of (the logarithm of) relative sales of VHS to Betamax in each year; (ii) an increase in the network advantage of VHS was an engine of tipping toward the VHS format; and (iii) in the early 1980s, the network advantage of VHS was mainly due to its expected growth advantage. © 2004 President and Fellows of Harvard College and the Massachusetts Institute of Technology.

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Simultaneous photoreduction of Pt(IV) ions and photooxidative polymerization of phenol on the surface of titanium(IV) oxide (TiO2) under ultraviolet light irradiation induced the formation of a composite, Pt-loaded TiO2 covered with a layer of phenolic polymer. Subsequent carbonization of the polymer layer and removal of TiO2 core particles yielded hollow carbon incorporated with platinum nanoparticles (nPt@hC). By varying the photoirradiation time, appreciable changes in density and porosity of the polymer layer and the carbon shell in nPt@hC were observed: prolonged irradiation induced a densification of the carbon matrix, resulting in a decrease in pore volume. Mainly due to the modulation of active surface of Pt nanoparticles, the densification of carbon was found to influence catalytic activity for hydrogenation of normal olefins.

Previous research has indicated that viewing 3D displays may induce greater visual fatigue than viewing 2D displays. Whether viewing 3D displays can evoke measureable emotional responses, however, is uncertain. In the present study, we examined autonomic nervous system responses in subjects viewing 2D or 3D displays. Autonomic responses were quantified in each subject by heart rate, galvanic skin response, and skin temperature. Viewers of both 2D and 3D displays showed strong positive correlations with heart rate, which indicated little differences between groups. In contrast, galvanic skin response and skin temperature showed weak positive correlations with average difference between viewing 2D and 3D. We suggest that galvanic skin response and skin temperature can be used to measure and compare autonomic nervous responses in subjects viewing 2D and 3D displays.

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