Catalytic epoxidation of olefins in the presence of a vanadyl porphyrin complex

It was found that vanadyl porphyrin complexes synthesized from petroleum metal porphyrin concentrates stimulated epoxidation during the olefin oxygenation process. The yields of obtained oxiranes turned out to be 38–75%, depending on the olefin structure. An epoxidation mechanism that suggests the formation of a protonated dioxygen adduct as an intermediate during oxygenation of olefins in the presence of vanadyl porphyrin complexes was proposed. An analogy is drawn between the epoxide formation reaction upon the catalytic oxygenation of olefins and the Prilezhaev reaction.     

Electrical and photoelectric properties of electrochemically fabricated SnO2/Cd0.4Zn0.6S/CdTe solar cells

Solar cells based on SnO₂/Cd_0.4Zn_0.6S/CdTe heterostructures are fabricated by electrochemical deposition, and the dependences of their electrical and photoelectric properties on the thermal annealing conditions are studied. It is shown that thermal annealing reduces the tunnel currents by almost two orders of magnitude. The best conditions of thermal annealing are determined (t = 300°C and τ = 9 min). These conditions provide the highest photosensitivity of the heterostructures under study (I _sc ≈ 21.2 mA/cm², U _oc ≈ 813 mV, and η = 14.7%).     

A fiber optic phase modulator with an optical frequency shift of up to 20 GHz

A fiber optic phase modulator is described in which the phase of a light wave traveling in an optical fiber is modulated by a composite electromechanical resonator with Q≌1000. The instantaneous frequency of the wave at the modulator output varies according to a harmonic law. The interval of tuning of the instantaneous light wave frequency achieved in the experiment is 20 GHz, which corresponds to a modulation index of ≌10⁶. It is demonstrated that a maximum value of the frequency tuning range is determined by the elastic limit of the resonator material.     

Electroplating of Lead Coatings Containing Small Amount of Tellurium

Plating conditions and some physicochemical properties of lead-tellurium coatings from a fluoboric acid bath are studied. The electroplates exhibit high microhardness, and a corrosion resistance in sulfuric acid media of 2–3 times that of pure electrolytic lead.     

Utilizing Radiant Nanoparticles in Silicon for Balanced White Color Adapters

Silicon - This work fully depends on the silicon nanoparticles. It is represented as SiNPs. This depends on the transparent LEDs color converters. The spectrum obtained is fully white, so it is...     

Stochastic Cellular Automata Solutions to the Density Classification Problem

In the density classification problem, a binary cellular automaton (CA) should decide whether an initial configuration contains more 0s or more 1s. The answer is given when all cells of the CA agree on a given state. This problem is known for having no exact solution in the case of binary deterministic one-dimensional CA. We investigate how randomness in CA may help us solve the problem. We analyse the behaviour of stochastic CA rules that perform the density classification task. We show that describing stochastic rules as a “blend” of deterministic rules allows us to derive quantitative results on the classification time and the classification time of previously studied rules. We introduce a new rule whose effect is to spread defects and to wash them out. This stochastic rule solves the problem with an arbitrary precision, that is, its quality of classification can be made arbitrarily high, though at the price of an increase of the convergence time. We experimentally demonstrate that this rule exhibits good scaling properties and that it attains qualities of classification never reached so far.     

Experimental reprocessing of waste cast-iron chips to the powder form

We have studied the possibility of producing powders from gray cast-iron chips formed during the production of home air conditioners. The particle morphology, structure, physicotechnical, mechanical, and antifriction properties of the cast iron powder are studied and compared to those of powdered iron. It is shown that the sample obtained from the cast-iron powder have worse mechanical properties than the samples prepared from iron but they have better antifriction properties than the latter.Bakkonditsioner Scientific-Industrial Complex. Translated from Poroshkovaya Metallurgiya, No. 2(362), pp. 93–98, February, 1993.     

Thermal-conductivity coefficients of six liquid aromatic hydrocarbons

Using experimental and data, equations are developed for six aromatic hydrocarbons which describe within the limits of experimental accuracy over the temperature range 298–573°K at pressures up to 500 bar.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 3, pp. 465–469, March, 1978.