Formation of ZrO<Subscript>2</Subscript> cubic phase microcrystals during crystallization of amorphous films deposited by laser ablation of Zr in an oxygen atmosphere

The structure and phase transformations during annealing of zirconium dioxide films grown by pulsed laser sputtering of a Zr target in an oxygen atmosphere have been studied by transmission electron microscopy and electron diffraction methods. The conditions of the formation of both amorphous and cubic ZrO₂ phases have been determined. The electron beam impact on the amorphous film in vacuum is accompanied by the formation of zirconium dioxide microcrystals with fcc lattice. The average grain size in the crystallized film is ～0.5 μm. The phase transformation is accompanied by film material densification. The relative change in the density during ZrO₂ crystallization is 10.27 ± 2.14%.     

Preferential protonation and methylation site of thiopyrimidine derivatives in solution: NMR data

Protonation (alkylation) sites of several thiopyrimidine derivatives were directly determined by 1H-15N (1H-13C) heteronuclear single quantum coherence/heteronuclear multiple bond correlation methods, and it was found that in all compounds, protonation (methylation) occurred at the N1 nitrogen. GIAO DFT chemical shifts were in full agreement with the determined tautomeric structures. According to ab initio calculations, the stability of the different protonated forms and methylated derivatives was favored due to thermodynamic control and not kinetic control.     

Extraction of titanium with phenol-formaldehyde resol oligomer Yarresin B from peroxide solutions

Extraction of titanium by nitrogen-containing phenol-formaldehyde oligomer Yarresin B from peroxide sulfate solutions was studied. Molecular dynamic (MD), molecular mechanic (MM), ZINDO/1 semiempirical (single-point calculations; program package HyperChem, Release 7.52, Hypercube Inc.) calculations, and the Cambridge Structure Database (ConQuest 1.8) were used to solve the structure of the extracted complex [Ti(O)₂OR(OH)₂]₂SO₄.     

Hybrid structures based on quantum dots and graphene nanobelts

Optics and Spectroscopy - Luminescence and photoelectric properties of hybrid structures based on CdSe/ZnS quantum dots (QDs) and multilayer graphene have been investigated. A correlation between...     

The Role of Physical Models in the Description of Luminescence Kinetics of Hybrid Nanowires

Optics and Spectroscopy - The luminescence photodynamics of an array of InP/InAsP/InP nanowires formed via molecular beam epitaxy onto a Si(III) substrate is investigated in this work. Using...     

Nonlinear vibrations of buried landmines

The seismo-acoustic method is one of the most promising emerging techniques for the detection of landmines. Numerous field tests have demonstrated that buried landmines manifest themselves at the surface through linear and nonlinear responses to acoustic/seismic excitation. The present paper describes modeling of the nonlinear response in the framework of the mass-spring model of the soil-mine system. The perturbation method used in the model allows for the derivation of an analytical solution describing both quadratic and cubic acoustic interactions at the soil-mine interface. This solution has been compared with actual field measurements to obtain nonlinear parameters of the buried mines. These parameters have been analyzed with respect to mine types and burial depths. It was found that the cubic nonlinearity could be a significant contributor to the nonlinear response. This effect has led to the development of a new intermodulation detection algorithm based on dual-frequency excitation. Both quadratic and intermodulation nonlinear algorithms were evaluated at the U.S. Army outdoor testing facilities. The algorithms appear to complement each other in improving the overall detection performance.     

Detecting vacuum entanglement in a linear ion trap

We propose and study a method for detecting ground-state entanglement in a chain of trapped ions. We show that the entanglement between single ions or groups of ions can be swapped to the internal levels of two ions by sending laser pulses that couple the internal and motional degrees of freedom. This allows us to entangle two ions without actually performing gate operations. A proof of principle of the effect can be realized with two trapped ions and is feasible with current technology.     

Reaction of the sodium salts of some hydroxypyrimidines with α,ω-dihaloalkanes Communication 4. Synthesis of N-(ω-haloalkyl)uracils

Conclusions A method has been developed for the preparation of 1,3-bis(-haloalkyl)uracils with methylene chains of different lengths in the -haloalkyl radicals in the N¹ and N³ positions of the pyrimidine ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1173–1177, May, 1986.