Optical Properties of Polyethylene Filled with Bi2Te3 Nanocrystallites

Semiconductors - Composite mixtures with various component concentrations are fabricated by the thermal pressing of low-density polyethylene and Bi2Te3 in the powder-like state with a nanocrystal...     

Determination of Some Photoluminescence Parameters of Ca(AlxGa1 –x)2S4:Eu2+

Technical Physics Letters - We synthesized a solid solution of Ca(AlxGa1 – x)2S4 activated with europium ions Eu2+. The photoluminescence spectra and photoluminescence excitation spectra of...     

Conversion of gas condensate on zinc-containing Ultrasil type high-silica zeolite

The catalytic properties of zinc-modified, Ultrasil type high-silica zeolite in thermal catalytic conversion of gas condensate to produce olefins and aromatic hydrocarbons have been studied. Methods for controlling the product composition by varying zinc concentration and by steaming the modified zeolite have been proposed. It has been shown that the treatment of Zn–H-Ultrasil leads to the formation of Brønsted type weakly acidic OH group having an absorption band at 3670 cm^–1, which reduces the contribution of hydrogen redistribution reactions and enhances selectivity for lower C₂–C₄ olefins.     

Optimizing depth resolution in confocal Raman microscopy: a comparison of metallurgical, dry corrected, and oil immersion objectives

Spherical aberration is probably the most important factor limiting the practical performance of a confocal Raman microscope. This paper suggests some simple samples that can be readily fabricated in any laboratory to test the performance of a confocal Raman microscope under realistic operating conditions (i.e., a deeply buried interface, rather than the often-selected alternative of a bare silicon wafer or a thin film in air). The samples chosen were silicon wafers buried beneath transparent polymeric or glass overlayers, and a polymer laminate buried beneath a cover glass. These samples were used to compare the performance of three types of objectives (metallurgical, oil immersion, and dry corrected) in terms of depth resolution and signal throughput. The oil immersion objective gave the best depth resolution and intensity, followed by a dry corrected (60x, 0.9 numerical aperture) objective. The 100x metallurgical objective was the worst choice, with degradations of approximately 5x and 8x in the depth resolution and signal from a silicon wafer, comparing a bare wafer with one buried under a 150 microm cover glass. In particular, the high signal level obtained makes the immersion objective an attractive choice. Results from the buried laminate were even more impressive; a 30x improvement in spectral contrast was obtained using the oil immersion objective to analyze a thin (19 microm) coating on a PET substrate, buried beneath a 150 microm cover glass, compared with the metallurgical objective.     

Thermoelectric properties of TlIn<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Eu<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Te<Subscript>2</Subscript> crystals

The thermoelectric properties of TlIn_{1 ? x} Eu _x Te₂ (0 < x ≤ 0.09) solid solutions have been studied at temperatures from 300 to 500 K. The results indicate that the thermoelectric figure of merit of the alloys increases with temperature and europium content.     

New Efficient Dielectric and Antistatic Materials Based on Oligoaminophenols

New polyconjugated oligomers—oligoaminophenols—have been prepared by the oxidative polycondensation reaction of aminophenols (APs) in the presence of oxidants (H₂O₂, NaOCl, KOH plus O₂). It has been established that the reactivity of AP increases with the series of m- < o- < p-isomers in this reaction. The oligoaminophenols synthesized show a high reactivity in electron-exchange processes and in reactions with the oxirane ring of epichlorohydrin and epoxy resins. They are highly efficient antioxidants and antistatic agents. © 1997 SCI     

A fiber-optic unit for measuring absolute distances and displacements with a nanometer resolution

A fiber-optic unit for measuring small absolute distances, namely, the base of the Fabry-Perot interferometer, formed by the fiber end and the reflecting surface from 30 to 250 μm with a resolution of no worse than 50 nm is described. The foundation for operation of the unit is the spectral method of the fiberoptic low-coherence interferometry.     

p-Hg0.8Cd0.2Te based large area fast photoresistor

The design and manufacturing technology of large area fast photoresistors by drawing additional electrodes on their back side are described. The measurement of the modernized p-Hg_0.8Cd_0.2Te based pho-toresistornal has shown that its operation speed increases inversely proportional to the reduction of the distance between adjacent electrodes.