3-Amino-1,2,4-triazolium salts as NHC-proligands: synthesis and postmodification of a new type of amino-functionalized Pd/NHC complexes

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Effect of hydrostatic pressure on self-diffusion in metal nanoparticles

The thermodynamics approach has been developed to describe the self-diffusion in nano-sized solids. It has been established that identical homologous temperatures of metal nanoparticles with their fixed characteristic size give the identical coefficients of diffusion under different pressures. The dependence of the activation enthalpy of diffusion on pressure and on the characteristic size of nanoparticles is first obtained.     

Application of the gradient heat flux sensor to study pulsed processes in a shock tube

The surface temperature of a model body of revolution placed in a pulsed supersonic nitrogen flow is measured with the help of a gradient heat flux sensor. From the measured temperature, a heat flux toward the surface of the body is determined. The steady flow of a viscous transcalent gas about the body is numerically calculated. The results of the numerical calculation and measuring data are in good agreement.     

Adjustment of the burning rate of a composite propellant with regard to its temperature sensitivity

Systematic multifactor experiments aimed at studying the regularities of the adjustment of the burning rate of composite propellants, especially its temperature sensitivity, were performed. It was established that, in contrast to the pressure dependence of the burning rate, which is largely determined by the properties of the base subsystem of components, its temperature sensitivity is influenced by the flame characteristics as well, more specifically, by the properties of the filler particles dispersed into the gas phase, a slowly burning component.     

Synthesis and reduction of 9-(α-nitrophenacylidene)-4-azafluorene

Reaction of 9-phenacylidene-4-azafluorene with acetyl nitrate produces a mixture of geometric isomers of 9-(-nitrophenacylidene)-4-azafluorene. The nitro group splits off upon reduction of the product in the system zinc-ammonia and zinc-acetic acid and on Raney nickel. Proceeding of the Henry retro-reaction has been pointed out.Russian Peoples' Friendship University, Moscow 117918, RussiaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 342–347, March, 1999.     

Vibrational equations of variable mass layers and membranes

Vibrations of layers and membranes, consisting of variable mass particles [1, 2], are considered. Adjacent and separated particles are classified. Differential equations and natural boundary conditions of vibrations of variable mass layers and membranes are derived. Two examples for vibrations are integrated by means of separation of variables.Translated from Zhurnal Prikladnoi Mekbaniki i Tekhnicheskoi Fiziki, No. 5, pp. 138–143, September–October, 1973.     

Local structure of Tm<Superscript>2+</Superscript> and Yb<Superscript>3+</Superscript> impurity centers in <Emphasis Type="Italic">Me</Emphasis>F<Subscript>2</Subscript> (<Emphasis Type="Italic">Me</Emphasis> = Ca,Sr, Ba) fluoride crystals

The local structure of Tm²⁺ and Yb³⁺ cubic impurity centers in MeF₂: Tm²⁺ and MeF₂: Yb³⁺ (Me = Ca, Sr, Ba) fluoride crystals, as well as Yb³⁺ trigonal and tetragonal impurity centers in MeF₂: Yb ³⁺ crystals, is calculated within the shell model in the pair potential approximation.     

The formation of the superheavy hydrogen isotope <Superscript>6</Superscript>H in the absorption of stopped π<Superscript>−</Superscript>-mesons by nuclei

An experimental search for the superheavy hydrogen isotope ⁶H was conducted through studying the absorption of stopped π^?-mesons by ⁹Be and ¹¹B nuclei. A structure in the missing mass spectrum caused by the resonance states of ⁶H was observed in three reaction channels, namely, ⁹Be(π^?, pd)X, ¹¹B(π^?, d³He)X, and ¹¹B(π^?, p⁴He)X. The parameters of the lowest state E_r=6.6±0.7 MeV and Γ=5.5±2.0 MeV (E_r is the resonance energy with respect to the disintegration into the triton and three neutrons) are evidence that ⁶H is a more weakly bound system than ⁴H and ⁵H. Three excited states of ⁶H were observed. Their resonance levels (E_1r=10.7±0.7 MeV, Γ_1r=4±2 MeV, E_2r=15.3±0.7 MeV, Γ _2r=3±2 MeV, and E_3r=21.3±0.4 MeV, Γ_3r=3.5±1.0 MeV) are energetically capable of disintegrating into six free nucleons.     

Alkoxylation of 1,2-Bis(methylchlorosilyl)ethylenes and -Acetylenes

Reactions of a series of 1,2-bis(methylchlorosilyl)ethylenes and -acetylenes Me_nCl_{3 - n}Si-Z-SiCl_{3 - n}Me_n (Z = CH = CH, CC; n = 0-2) with ethanol and acetoxime were studied. Novel alkoxy- and isopropylideneaminooxysilanes were obtained and characterized. A relation was found between the activity of Si-Cl bonds in the reactions studied and the structure of the carbon-carbon bridge.