Formation of polarity-sensitive input <Emphasis Type="Italic">I-V</Emphasis> characteristics of a bidirectional triode thyristor

A family of input I-V characteristics of a planar diffused bidirectional triode thyristor (triac) is obtained. The formation of an N-shaped portion in the input characteristic is explained. It is shown that the input N-shaped characteristic may form in various input circuits of a triac depending on the voltage polarity across power electrodes.     

Non-linear ramsey resonance in the optical region

The interaction of gas particles with three separated light fields has been considered. It has been shown that a resonance with the width equal to the reciprocal transit time appears in such a system. The resonance is due to coherence conservation and change of distribution of a number of particles by nonlinear interaction with the fields. Its properties are close to the Ramsey resonance in the microwave range. This new type of resonance may have a relative width of 10⁻¹¹ to 10⁻¹².     

Influence of field on the lamb dip centre shift with account of recoil effect

The use of a nematic liquid crystal cell under a magnetic field is described for successive subtraction holography.     

Role of structural noise in aircraft pressure cockpit from vibration action of new-generation engines

The evolution of new-generation aircraft engines is transitioning from a bypass ratio of 4–6 to an increased ratio of 8–12. This is leading to substantial broadening of the vibration spectrum of engines with a shift to the low-frequency range due to decreased rotation speed of the fan rotor, in turn requiring new solutions to decrease structural noise from engine vibrations to ensure comfort in the cockpits and cabins of aircraft.     

New nonlinear resonances in a gas in the presence of a strong optical field

The present paper offers the solution to the probe of the nonlinear interaction of a weak standing wave with a two-level gas in the field of a strong travelling wave. It turns out that a number of new nonlinear resonances with a homogeneous width arise on the background of linear absorption.     

Synthesis of Perfluorinated Dioxo Esters from Dimethyl Perfluoroadipate

Russian Journal of Organic Chemistry -     

Electrical transport and magnetic ordering in R 2Ti3Ge4 (R=Dy, Ho and Er) compounds

New R ₂Ti₃Ge₄ (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize in the parent, Sm₅Ge₄-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series. The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects.     

Reaction of trimethylchlorosilane in spin-on Silicalite-1 zeolite film

We present a study on the hydrophobization of spin-on Silicalite-1 zeolite films through silylation with trimethylchlorosilane. Microporous and micro-mesoporous Silicalite-1 films were synthesized by spin coating of suspensions of Silicalite-1 nanozeolite crystallized for different times. Ellipsometric porosimetry with toluene and water adsorbates reveals that silylation decreases the porosity and makes the films hydrophobic. The decrease in porosity depends on the exposed surface area in the pores. Water contact angle measurements confirm the hydrophobicity. Fourier transform infrared spectroscopy reveals that the trimethylsilyl groups are chemisorbed selectively on isolated silanols and less on geminal and vicinal silanols due to steric limitations. Time-of-flight secondary-ion mass spectroscopy and in situ ellipsometry analysis of the reaction kinetics show that the silylation is a bulk process occurring in the absence of diffusion limitation. Electrical current leakage on films decreases upon silylation. Silylation with trimethylchlorosilane is shown to be an effective hydrophobization method for spin-on Silicalite-1 zeolite films.     

Freezing of low energy excitations in charge density wave glasses

Thermally stimulated discharge current measurements were performed to study slow relaxation processes in two canonical charge density wave systems K(0.3)MoO(3) and o-TaS(3). Two relaxation processes were observed and characterized in each system, corroborating the results of dielectric spectroscopy. Our results are consistent with the scenario of the glass transition on the charge density wave superstructure level. In particular, the results directly prove the previously proposed criterion of charge density wave freezing based on the interplay of charge density wave pinning by impurities and screening by free carriers. In addition, we obtained new information on distribution of relaxation parameters, as well as on nonlinear dielectric response both below and above the threshold field for charge density wave sliding.