Existence regions of regimes with anomalously high rates of plasma generation in grid plasma switch elements

Results are presented from a systematic investigation of the conditions under which anomalously high rates of plasma generation are observed in the anode region of a low-voltage Knudsen arc in grid plasma switch elements. The phenomenon develops over a wide range of currents and switched voltages under conditions for which the plasma density in the cathode-grid region is noticeably higher than the density in the anode region. and its onset is characterized by a pronounced pressure threshold of ∼2×10⁻² Torr. The results are analyzed from the standpoint of the possible mechanisms for anomalous plasma generation — collisional nonresonance diffusion of electrons in velocity space, leading to enrichment of the distribution function in fast particles, and the collapse of Langmuir waves in the gap at the high energies of the beam produced when the wires of the grid are bridged by the quenching pulse and and the current is blocked. Zh. Tekh. Fiz. 67, 15–21 (June 1997)     

New palladium nanoclusters. Synthesis,structure, and catalytic properties

The reduction of palladium(ii) carboxylates Pd₃(OCOR)₆ (R = Me, Et, CHMe₂, CMe₃) with hydrogen in alcohol solutions containing 1,10-phenanthroline (phen) and subsequent oxidation with oxygen gave new palladium nanoclusters, mainly particles with a nearly spherical metal core and an average size of 18 . Based on elemental analysis, NMR, X-ray photoelectron spectroscopy, and EXAFS, nanoclusters were described by the idealized formula Pd₁₄₇phen₃₂O₆₀(OCOR)₃₀. The specimens contained up to 25% smaller 55-atomic Pd clusters with a 10 metal core. New nanoclusters catalyze hydrogenation of alkynes and alkenes, reduction of nitriles with formic acid, oxidation of aliphatic and benzylic alcohols, oxidative esterification of ethylene and propylene, and disproportionation of benzyl alcohol into toluene and benzaldehyde.     

Dual linear connections on fitted manifolds of a space with projective connection

This paper presents an investigation of dual linear connections (projective and affine), induced by different fittings of a space with a projective connection P_n,n, a regular hypersurface V_n-1P _n,n , and a regular hyperbandH _m P _n,n .Translated from Itogi Nauki i Tekhniki. Problemy Geometrii, Vol. 8, pp. 25–46, 1977.     

Grid control over high currents in a cesium discharge with a cathode spot

We report on the results of investigation of a plasma switch with complete grid control in a discharge with a cathode spot on the liquid-metal cesium cathode without grid diaphragming. The retention of the working area of the grid relative to the anode area leads to an order-of-magnitude increase in the switching anode current (up to 20 A/cm² over the anode area) and a substantial (up to 100 V and higher) increase in the switching voltages. The use of the cathode jet makes it possible to reduce the working pressures of cesium vapor (down to 10^–3 Torr). We discuss the results of analysis of peculiarities of grid discharge quenching in such a switch, which make it possible to determine possible reasons for limitation of the working parameters of the switch and the ways of their further increase.     

Structures of the products of condensation of phthalazone hydrazones with mesityl oxide

It was established on the basis of data from the UV and PMR spectra, the dipole moments, and the synthesis of fixed structures that the products of the condensation of phthalazone hydrazones with mesityl oxide have the structures of mixed phthalazone azines and mesityl oxide rather than the phthalazinylhydrazone structure that was previously assumed for them.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 678–683, May, 1981.     

Effect of the nature of carboxylate anion on the features of intramolecular hydrogen bonding in [Pd(Hdmpz)<Subscript>4</Subscript>](OOCR)<Subscript>2</Subscript> (R = Me,Bu<Superscript>t</Superscript>, Ph)

We discovered that reactions of [Pd(OOCMe)₂] _n and Pd₃(μ-OOCMe) with 3,5-dimethylpyrazole (Hdmpz) yield mononuclear complex [Pd(Hdmpz)₄](OOCMe)₂, in which acetate anions can exchange for pivalate or benzoate anions in reactions with proper acids. The specifics of intramolecular hydrogen bonding in the complexes prepared are discussed as dependent on the nature of the carboxylate anion using X-ray crystallography data.