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11.
Berta Perlmutter-Hayman 《Israel journal of chemistry》1971,9(3):377-384
Instances of temperature-dependent apparent energies of activation EA, observed for hydrolysis reactions, are briefly reviewed, as are recent calculations according to which the presence of a reactant in two forms which are in mobile equilibrium may lead to a temperature-dependent EA. These calculations are extended to a consideration of the temperature-dependence of the specific heat of activation, and to the possibility of more than two forms being in equilibrium. It is shown in some detail how the equilibrium between broken and intact hydrogen bonds in water may be responsible for observed effects. 相似文献
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13.
Francesco Bellotti Riccardo Berta Alessandro De Gloria Massimiliano Margarone 《Personal and Ubiquitous Computing》2002,6(3):155-163
Future generation cars will be characterized by a wide range of Information Technology (IT) services providing safety and
infotainment. This makes the car an information intensive environment where the visual channel is overloaded, putting the
safety of drivers and passengers in jeopardy. We propose the use of a 3D auditory display to provide information from the
Advanced Driver Assistance Systems. This reduces the eye-off-road time, exploiting the human capability to associate sounds
with positions in space. Preliminary lab tests reveal the suitability of this approach. The system still has to be carefully
tuned and personalized to achieve usability and reliability, but we think that it provides a complementary channel that is
specially useful in low visibility conditions. 相似文献
14.
Paulo S. André António L. Teixeira Armando N. Pinto Lara P. Pellegrino Berta B. Neto José F. Rocha Joäo L. Pinto Paulo N. Monteiro 《ETRI Journal》2006,28(2):257-259
In this letter, we will evaluate the performance degradation of a 40 km high‐speed (40 Gb/s) optical system, induced by optical fiber variations of the chromatic dispersion induced by temperature changes. The chromatic dispersion temperature sensitivity will be estimated based on the signal quality parameters. 相似文献
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The relation between shear holding power and pressure-sensitive adhesive (PSA) rheological properties is investigated. Two constitutive models of PSA rheology, i.e., Newtonian and Power Law, are considered and experimentally tested for their ability to predict shear holding power. A Power Law model is found to be suitable for this purpose and is used to predict shear holding power with dynamic viscosity and steady shear viscosity measured by means of a transient creep experiment. Dynamic viscosity is shown to fail in predicting shear adhesion of high-viscosity PSA, whereas steady shear produces good agreement. It is demonstrated that the Cox-Merz rule does not hold for high-viscosity PSAs, explaining the need for steady shear viscosity data in modeling shear holding power. 相似文献
17.
Dr. Matthias Hauf Dr. Florian Richter Tobias Schneider Thomas Faidt Dr. Berta M. Martins Dr. Tobias Baumann Dr. Patrick Durkin Prof. Dr. Holger Dobbek Prof. Dr. Karin Jacobs Prof. Dr. Andreas Möglich Prof. Dr. Nediljko Budisa 《Chembiochem : a European journal of chemical biology》2017,18(18):1771-1771
18.
Hugo M. Santos Bruno Pedras Abel Tamayo Jaume Casabó Lluis Escriche Berta Covelo José Luis Capelo Carlos Lodeiro 《Inorganic chemistry communications》2009,12(11):1128-1134
Two new emissive chemosensors based on coumarin-343 have been synthesized, and their photophysical studies conducted. L1 contains an aza-thio macrocycle ring as the chelating unit, which has great affinity for soft metal ions, whereas L2 is a parent species without macrocyclic unit. Both compounds were separated by column chromatography and characterized by elemental analysis, 1H,13C NMR, UV–vis and FAB mass spectroscopy. The X-ray structures of L1 and L2 and the supramolecular interactions in the solid state are discussed. Preliminary results on the metal–ion sensing effects of the ligands are presented. Titrations with Ag+, Pd2+ and Ni2+ have been studied by UV–vis absorption and fluorescence spectroscopy. 相似文献
19.
Berta Gonçalves Ana Paula Silva José Moutinho-Pereira Eunice Bacelar Eduardo Rosa Anne S. Meyer 《Food chemistry》2007,103(3):976-984
The relationship between colour parameters and anthocyanins of four sweet cherry cultivars, Burlat, Saco, Summit and Van was studied. The colour (L∗, a∗, b∗, chroma and hue angle parameters) and anthocyanins were analysed during two different years at two different ripening stages (partially ripe, and ripe, respectively). The cherries were analysed at harvest and after storage at 1.5 ± 0.5 °C and 15 ± 5 °C for 30 and 6 days, respectively. The colour was measured by tristimulus colourimetry (CIELAB system) directly on the fruits, while anthocyanins were quantified by HPLC-DAD analysis on methanolic extracts of freeze-dried samples of the fresh cherries and on the differently stored cherries. L∗, chroma, and hue angle values were always lower for the ripe than for the partially ripe cherries. All of the cultivars were found to contain cyanidin-3-rutinoside and cyanidin-3-glucoside as the major anthocyanins. The total anthocyanin content in fruits of the different cultivars varied in the order Burlat > Saco > Van > Summit. The concentration of anthocyanins increased at both temperatures of storage in both ripe and partially ripe cherries, but the extent of increase varied among cultivars. Cherries stored at 15 ± 5 °C showed higher reduction of L∗, chroma and hue angle than fruits stored at 1.5 ± 0.5 °C. L∗, a∗, b∗, chroma and hue angle correlated negatively (P < 0.001) with the total anthocyanins levels, but not with the total phenols. These results show that chromatic functions of chroma and hue correlate closely with the evolution of colour and anthocyanins levels during storage of sweet cherries and indicate that colour measurements can be used to monitor pigment evolution and anthocyanin contents of cherries (and vice versa). 相似文献
20.
Fernandez J. Hidalgo S. Paredes J. Berta F. Rebollo J. Millan J. Serra-Mestres F. 《Electron Device Letters, IEEE》1989,10(5):212-215
An analytical ON-resistance expression for different designs of VDMOS (vertically diffused metal-oxide-semiconductor) devices which takes into consideration the two-dimensional (2-D) nature of the current flow is obtained. This expression differs from other models that overestimate this resistance for large cell spacings. This formulation is in close agreement with experimental points obtained from the interdigitated fabricated structures and with 2-D simulations. Moreover, the effect of a two-level oxide thickness on the ON resistance has been investigated for the interdigitated case 相似文献