A logarithmic expression is proposed to describe relaxation of the polar order in side chain polymers, together with a new way of plotting temperature dependent relaxation data. This results in a straight line extendi...A logarithmic expression is proposed to describe relaxation of the polar order in side chain polymers, together with a new way of plotting temperature dependent relaxation data. This results in a straight line extending even below the glass transition temperature in the case of poled nonlinear optics (NLO) side chain polymers. A simple procedure to determine the rotational diffusion constant D-r is given and D-r values of several polymer systems have been evaluated and compared with each other. It appears that, starting from the conventional and well known poled polymer system currently applied, a further lowering of D-r by about 3 orders of magnitude is necessary in order to reach an acceptable orientational stability or lifetime of poled polymers for practical applications. Attempts have been made to introduce electron push-pull substituents into high thermostable molecular frameworks and results of preliminary measurements are reported.展开更多
Equilibrium constants for the binding of azide to ferri-cytochrome c at temperature range of 305—325 K were determined at pH=7 by using ~1H double resonance method.Thermodynamic values(⊿H^o=-34.5 kJ/mol,⊿S^o=-100 J...Equilibrium constants for the binding of azide to ferri-cytochrome c at temperature range of 305—325 K were determined at pH=7 by using ~1H double resonance method.Thermodynamic values(⊿H^o=-34.5 kJ/mol,⊿S^o=-100 J/mol)were obtained from van't Hoff's relation and were compared with those for azide binding to other ferric hemeproteins.The reason of lower affinity of cytochrome c for azide was discussed.展开更多
文摘A logarithmic expression is proposed to describe relaxation of the polar order in side chain polymers, together with a new way of plotting temperature dependent relaxation data. This results in a straight line extending even below the glass transition temperature in the case of poled nonlinear optics (NLO) side chain polymers. A simple procedure to determine the rotational diffusion constant D-r is given and D-r values of several polymer systems have been evaluated and compared with each other. It appears that, starting from the conventional and well known poled polymer system currently applied, a further lowering of D-r by about 3 orders of magnitude is necessary in order to reach an acceptable orientational stability or lifetime of poled polymers for practical applications. Attempts have been made to introduce electron push-pull substituents into high thermostable molecular frameworks and results of preliminary measurements are reported.
文摘Equilibrium constants for the binding of azide to ferri-cytochrome c at temperature range of 305—325 K were determined at pH=7 by using ~1H double resonance method.Thermodynamic values(⊿H^o=-34.5 kJ/mol,⊿S^o=-100 J/mol)were obtained from van't Hoff's relation and were compared with those for azide binding to other ferric hemeproteins.The reason of lower affinity of cytochrome c for azide was discussed.
