Reactions of α-trifluoromethyl-β-chloroethylsulfenyl chloride with phenols and their derivatives

In the absence of a catalyst, -trifluoromethyl--chloroethylsulfenyl chloride reacts electrophilically with ortho-para-substituted phenols bearing substituents of the first type. The reaction conditions are determined by the C-nucleophilic properties of the phenol, and the selectivity by solvent effects. These -trifluoromethyl--chloroethylthiolated phenols are shown to be highly prone to dehydrochlorination.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 832–837, April, 1990.     

Structure of metallic nanowires and nanoclusters formed in superfluid helium

It is shown that metallic nanowires (5–8 nm in diameter) that form during laser ablation of Ni, Pb, In, and Sn targets embedded in HeII contain extended single-crystal segments, while spherical clusters (about 2 μm in diameter) that form under these conditions have a regular shape and an atomically smooth surface. Such structures are explained by melting of metal ablation products under their coalescence in HeII. The short-term action of a low-intensity beam of electrons with an energy of 200 keV initiates the explosion in metallic spheres preserved in the vacuum chamber of a transmission electron microscope, which is accompanied with the formation of thousands of clusters with a diameter of a few nanometers. This effect is due to metastability of internal mechanical stresses produced upon sharp cooling of molten spheres by liquid helium. A mechanism of condensation of atoms and nanoparticles in quantized vortices of superfluid helium is proposed.     

A complex study of structural imperfections of the CdTe and CdTe: Cl crystals grown by the sublimation method

The structure of CdTe and CdTe: Cl crystals grown by the modified physical vapor transport method has been investigated using selective chemical etching, electron diffraction, and X-ray diffractometry. It has been established that the structural perfection is improved in the growth direction and from the periphery of the radial cross section toward the center of the crystal. It has been shown that the thermomechanical stresses generated by the adhesion of the crystals to the walls of the growth ampoule are the main source of the formation of dislocations and the factor responsible for their nonuniform distribution over the volume of ingots.     

Linear HgCdTe IR FPA 288×4 with bidirectional scanning

The long wavelength (8–12 μm) IR FPA 288×4 based on a hybrid assembly of n⁺-p diode photosensitive arrays (PA) of HgCdTe (MCT) MBE-grown structures and time delay integration (TDI) readout integrated circuits (ROIC) with bidirectional scanning have been developed, fabricated, and investigated. The p-type MCT structures were obtained by thermal annealing of as-grown n-type material in inert atmosphere. The MCT photosensitive layer with the composition 0.20–0.23 of mole fraction of CdTe was surrounded by the wide gap layers to decrease the recombination rate and surface leakage current. The diode arrays were fabricated by planar implantation of boron ions into p-MCT. The typical dark currents were about 4–7 nA at the reverse bias voltage of 150 mV. The differential resistance R was up to R₀ = 1.6×10⁷ Ω zero bias voltage, which corresponded to R₀A ～70 Ω ·cm² and to the maximal value R_max = 2.1 × 10⁸ Ω. The bidirectional TDI deselecting ROIC was developed and fabricated by 1.0-μm CMOS technology with two metallic and two polysilicon layers. The IR FPAs were free of defect channels and have the average values of responsivity S_λ = 2.27×10⁸ V/W, the detectivity D_λ ^* = 2.13 × 10¹¹ cm × Hz^1/2 × W^t1, and the noise equivalent temperature difference NETD = 9 mK.