277 research outputs found
Complex Permittivity Measurements at Variable Temperatures of Low Loss Dielectric Substrates Employing Split Post and Single Post Dielectric Resonators
A split post dielectric resonator in a copper enclosure and a single post
dielectric resonator in a cavity with superconducting end-plates have been
constructed and used for the complex permittivity measurements of single
crystal substrates. (La,Sr)(Al,Ta)O3, LaAlO3, MgO and quartz substrates have
been measured at temperatures from 20 K to 300 K in the split post resonator
and from 15 K to 80 K in the single post resonator. The TE01delta mode resonant
frequencies and unloaded Qo-factors of the empty resonators at temperature of
20 K were: 9.952 GHz and 25,000 for the split post resonator and 10.808 GHz and
240,000 for the single post resonator respectively.Comment: 4 pages, 8 figures, 1 tabl
Synthesis of Benzylidene and Azo Containing Polymers for Photophisical Application
In the present work, the polymers built with the use of the free radical polymerization of methacrylic monomers incorporating an azobenzene side-group and monomers with benzylidene fragments have been synthesized. The polymerization was carried out in DMF with AIBN as initiator. The products of polymerization were characterized by HNMR. The results of investigations of photochemical and optical activities of the corresponding polymers are presented
Reversible recording medium based on optical storage of information, method of reversible recording on such a medium.
A reversible recording medium based on optical storage of at least one item ofinformation within a support material, includes at least one layer of support material having: base molecules able to take, in a local zone, a first collective state of molecules able to generate a first signal of second harmonic characteristic of this first collective state of molecules when excited by electromagnetic reading radiation; the base molecules having the first collective state of molecules able to transform, at least in part, into transformed molecules so as to pass to a second collective state of molecules when excited by electromagnetic writing radiation, the molecules having the second collective state of molecules able to generate a second signal of second harmonic characteristic of this second collective state of molecules when excited by the electromagnetic reading radiation. The molecules exhibit a molecular structure based on a coumarin skeleton of Formula (I)
Reversible Two-Photon Optical Data Storage in Coumarin-Based Copolymers
A functionalized polymer film allowing for a complete and straightforward second-harmonic generation (SHG)-assisted high-contrast writing?reading?erasing?writing sequence is proposed. The whole process is supported by the reversible photoinduced dimerization of a coumarin chromophore and enables efficient optical data storage that can be detected only by SHG imaging
Synthesis, photophysical and photochemical properties of oxazolone derivatives
Acyloxyphenyl derivatives of oxazolone, which have tree photo active centers, were synthesized and their physicochemical properties are determined by NMR, absorption, fluorescence excitation and emission spectroscopies. The semi-empirical calculations carried out according with the theory of the PM3/Cl level has shown, that at an irradiating of their solutions by UV-light give no possibilities of the photo-Fries reaction. The calculated values are in a good accordance with the experimental ones
On a Order Reduction Theorem in the Lagrangian Formalism
We provide a new proof of a important theorem in the Lagrangian formalism
about necessary and sufficient conditions for a second-order variational system
of equations to follow from a first-order Lagrangian.Comment: 9 pages, LATEX, no figures; appear in Il Nuovo Cimento
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