Studies above ambient pressure

Polymeric liquid crystals have been extensively studied at ambient pressure because of their potential applications for electro-optical switching or storage effects. " However, high-pressure studies are very scarceAt least five different relaxation processes are observed two of them above the glass transition (a and 6) and... 

Similar to studies reported by Litwinienko and co-workers discussed above, a recent report (Dunn, 2006b) demonstrated that non-isothermal (conventional) DSC, static mode P-DSC and dynamic mode P-DSC may be employed to study kinetics of the oxidation of SME. OT results obtained at ambient pressure for DSC and P = 2000kPa for P-DSC and with varying p = 1-20 °C/ min were analyzed by the Ozawa-Flynn-Wall method to calculate activation energies and rate constants. This work concluded that rates of the oxidation reaction could be calculated at any temperature based on accurate measurement of kinetic parameters from analysis of non-isothermal dynamic mode P-DSC scans. 

Among the [M(dmit)2]-based superconductors, a-[EDT-TTF][Ni(dmit)2] is also of DA type and has two outstanding features it is the oiJy one to contain a 1 1 molar ratio of donor and acceptor units and to exhibit superconductivity at ambient pressure. The phase is superconductive below 1.3 K under ambient pressure (Figure 4.24). a-[EDT-TTF] [Ni(dmit)2] exhibits a unique metallic behaviour with a characteristic resistivity peak at around 14 K. Magnetoresistance studies shown that the conduction mainly takes place along the Ni(dmit)2 stacks below 10 K, while both [Ni(dmit)2] and [EDT-TTF] stacks are involved above... 

Webster and Drickamer [255] studied the Dj Fj emission of Eu + (4f ) doped at several concentrations in LajOjS as a function of pressure. The energy level diagram of Eu + is shown in Fig. 19. Emission spectra were measured upon excitation into the charge transfer state. At ambient pressure, emission occurs from the Dq 12 states to several of the Fj states. Upon increasing pressure up to 110 kbar, the emission intensity from the i states was observed to decrease steadily. On the contrary, emission intensity from the D2 state increased between 0 kbar and 20 kbar, remained approximately constant between 20 kbar and 80 kbar, and decreased above 80 kbar. The decrease in D2 intensity coincided with the onset of new emission from the state. In addition to intensities, Webster and Drickamer also measured the emission Hfetimes from the Di 2,3 states. The values of the lifetimes depended on the Eu + concentration, but the trends with pressure were uniform. The emission lifetime remained nearly constant with pressure while the D2 emission Hfetime increased between 0 kbar and 20 kbar and remained constant above 20 kbar. The D3 lifetime could be measured above 70 kbar and was observed to increase up to 110 kbar. 

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