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The pressure-induced chemical reaction of liquid butadiene was studied by Fourier transform infrared spectroscopy in a diamond anvil cell. Dimerization was found to occur above 0.7 gigapascal, giving vinylcyclohexene according to a cyclo-addiction reaction and only a trace amount of polybutadiene forms. By irradiating the high-pressure sample with a few(More)
and time between 15 and 60 minutes. Experimental data, i.e. treatment yield, chemical consumption, acid groups content and swelling measured by WRV are fitted to polynomial equations. The relationship between swelling and the chemical state of the wood is analysed. The evolution of swelling reaches maximum levels within the time period. The ionic content(More)
High-pressure methods are increasingly used to produce new dense materials with unusual properties. Increasing efforts to understand the reaction mechanisms at the microscopic level, to set up and optimize synthetic approaches, are currently directed at carbon-based solids. A fundamental, but still unsolved, question concerns how the electronic excited(More)
Two-photon excitation profiles and fluorescence spectra have been measured as a function of pressure in a diamond anvil cell up to 15.5 GPa in crystal phases I and II and in the glassy form of pyridine. The fluorescence emission intensity increases by about 6 orders of magnitude in going from the liquid to the crystalline phases at 3 GPa and further(More)
The high-pressure reactivity of isoprene has been studied at room temperature up to 2.6 GPa by using the diamond anvil cell technique in combination with Fourier transform infrared spectroscopy. Both dimerization and polymerization reactions take place above 1.1 GPa. At this pressure, the two processes are well separated in time, the dimerization being the(More)
Liquid water has a primary role in ruling life on Earth in a wide temperature and pressure range as well as a plethora of chemical, physical, geological, and environmental processes. Nevertheless, a full understanding of its dynamical and structural properties is still lacking. Water molecules are associated through hydrogen bonds, with the resulting(More)
The phase diagram of propene has been investigated at high pressure by using the diamond anvil cell technique and Fourier transform infrared spectroscopy. The pressure conditions necessary to induce a spontaneous reaction of the sample have been found at different temperatures, allowing the stability boundary of propene to be drawn. The reaction is(More)
During the years 1979-1982 we treated by argon laser photocoagulation 863 eyes of 551 patients affected by peripheral retinal degenerations and breaks. No case of progression to retinal detachment has been registered so far. In the same period, we treated 42 patients affected by retinal detachment of different topography (three posterior pole and 39(More)