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21.
22.
Kolker D. B. Sherstov I. V. Boiko A. A. Kostyukova N. Yu. Erushin E. Yu. Pavlyuk A. V. 《Journal of Applied Spectroscopy》2022,89(4):742-747
Journal of Applied Spectroscopy - The generation regimes of quantum-cascade lasers for optoacoustic sensors of methane and ammonia are examined, and the tuning and output characteristics of these... 相似文献
23.
M.?V.?LobanovEmail author E.?B.?Pomakhina A.?I.?Rebrov A.?L.?Krasovskiy A.?A.?Yaroslavov K.?A.?Shashkeev B.?Ph.?Pavlyuk 《Russian Journal of Applied Chemistry》2018,91(1):40-48
A simple method that was used to obtain stabilized ZnO nanoparticles and their dispersions in water is presented. It yields anisotropic (trigonal prismatic) nanocrystals with dimensions below 50 nm. The Partial Profile Relaxation (PPR) technique was applied in the analysis of X-ray diffraction data with complex anisotropic broadening. Ethylene diamine catalyzed silanization was utilized for the covalent surface functionalization, which allowed us to obtain stable waterborne dispersions when aminosilanes were used. The difference in the surface structure of ZnO nanoparticles for different variants of functionalization was investigated by 29Si NMR spectroscopy. The combination of X-ray diffraction and dynamic light scattering data indicates minimal degree of particle agglomeration in the dispersions. 相似文献
24.
EP Sheretov VS Gurov MV Dubkov OV Korneeva 《Rapid communications in mass spectrometry : RCM》1999,13(16):1699-1702
In this article we compare the classical monopole mass filter of von Zahn and the monopole mass filter with a hyperbolic V-shaped electrode. The experimental results and those of computer simulation for both mass spectrometers are presented. We show that the replacement of a conventional 90 degrees V-shaped electrode by an electrode with a hyperbolic profile substantially improves the peak shape of any given mass, and increases the mass resolution by a factor of 3-4 and the abundance sensitivity by a factor of 100. The potential of high analytical performance combined with electroforming techniques for electrode manufacture indicate future practical uses of such instruments. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
25.
Nazar Pavlyuk Grygoriy Dmytriv Alina Bondaruk Wojciech Ciesielski Volodymyr Pavlyuk 《Acta Crystallographica. Section C, Structural Chemistry》2024,80(5):159-165
The ternary germanide Mg5.57Ni16Ge7.43 (cubic, space group Fmm, cF116) belongs to the structural family based on the Th6Mn23-type. The Ge1 and Ge2 atoms fully occupy the 4a (mm symmetry) and 24d (m.mm) sites, respectively. The Ni1 and Ni2 atoms both fully occupy two 32f sites (.3m symmetry). The Mg/Ge statistical mixture occupies the 24e site with 4m.m symmetry. The structure of the title compound contains a three-core-shell cluster. At (0,0,0), there is a Ge1 atom which is surrounded by eight Ni atoms at the vertices of a cube and consequently six Mg atoms at the vertices of an octahedron. These surrounded eight Ni and six Mg atoms form a [Ge1Ni8(Mg/Ge)6] rhombic dodecahedron with a coordination number of 14. The [GeNi8(Mg/Ge)6] rhombic dodecahedron is encapsulated within the [Ni24] rhombicuboctahedron, which is again encapsulated within an [Ni32(Mg/Ge)24] pentacontatetrahedron; thus, the three-core-shell cluster [GeNi8(Mg/Ge)6@Ni24@Ni32(Mg/Ge)24] results. The pentacontatetrahedron is a new representative of Pavlyuk's polyhedra group based on pentagonal, tetragonal and trigonal faces. The dominance of the metallic type of bonding between atoms in the Mg5.57Ni16Ge7.43 structure is confirmed by the results of the electronic structure calculations. The hydrogen sorption capacity of this intermetallic at 570 K reaches 0.70 wt% H2. 相似文献
26.
M. M. Monchak A. V. Pavlyuk V. V. Kinzhibalo M. G. Mys’kiv 《Russian Journal of Coordination Chemistry》2009,35(6):405-410
The alkylation of ethylenediamine with allyl bromide in the presence of a fourfold (with respect to ethylenediamine) molar
amount of NaHCO3 in acetone with an ethanol admixture (15: 1) affords LBr2 · 2H2O (I), where L2+ is the N,N,N,N′,N′,N′-hexaallylethylenediaminium cation. Single crystals of complexes L[CuII(Br0.45Cl3.55)] (II), L[Cu4I(Br4.55Cl1.45)] (III), and L[Cu4IBr6] (IV) are prepared by ac electrochemical synthesis from an ethanolic solution of LBr2 · 2H2O, CuCl2 · 2H2O (or CuBr2) at copper wire electrodes. The crystal structures of compounds I–IV are determined by X-ray diffraction analysis. The crystals of complex I are monoclinic: space group P21/n, a = 8.544(3), b = 10.404(3), c = 13.350(4) ?, β = 97.29(3)°, V = 1177.2(6) ?3, Z = 2. The bromine anions in compound I are bonded to the L2+ cations and water molecules through hydrogen contacts (E)H…Br (E = O, C) of 2.57(3)–2.86(3) ?. The crystals of compounds
II–IV are triclinic: space group P
. For II: a = 8.762(4), b = 9.163(4), c = 16.500(6) ?, α = 95.62(4)°, β = 96.39(4)°, γ = 111.46(4)°, V = 1211.4(9) ?3, Z = 2; for III: a = 9.074(4), b = 9.435(4), c = 9.829(5) ?, α = 116.12(4)°, β = 104.14(4)°, γ = 100.22(4)°, V = 692.3(6) ?3, Z = 1; for IV isostructural III: a = 9.084(4), b = 9.404(4), c = 9.869(4) ?, α = 116.31(3)°, β = 104.00(3)°, γ = 100.37(3)°, V = 692.1(5) ?3, Z = 1. Unlike the isolated tetrahedral CuX42− anion in structure II, an original chain anion (Cu4X62−)
n
is observed in the structures of π complexes III and IV.
Original Russian Text ? M.M. Monchak, A.V. Pavlyuk, V.V. Kinzhibalo, M.G. Mys’kiv, 2009, published in Koordinatsionnaya Khimiya,
2009, Vol. 35, No. 6, pp. 414–419. 相似文献
27.
Igor Oshchapovsky Volodymyr Pavlyuk Grygoriy Dmytriv Alexandra Griffin 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(6):i37-i40
The structure of lanthanum tetrazinc, LaZn4, has been determined from single‐crystal X‐ray diffraction data for the first time, approximately 70 years after its discovery. The compound exhibits a new structure type in the space group Cmcm, with one La atom and two Zn atoms occupying sites with m2m symmetry, and one Zn atom occupying a site with 2.. symmetry. The structure is closely related to the BaAl4, La3Al11, BaNi2Si2 and CaCu5 structure types, which can be presented as close‐packed arrangements of 18‐vertex clusters, in this case LaZn18. The kindred structure types contain related 18‐vertex clusters around atoms of the rare earth or alkaline earth metal. 相似文献
28.
Enantiomerically enriched cyclopropanes and products of C–H insertion reactions were obtained in excellent combined yields and enantioselectivities as a consequence of rhodium-catalyzed decomposition of vinyl diazoacetate in the presence of tert-butoxycarbonyl-(Boc)-protected amines as trapping agents. A series of enantiomerically enriched six- to eight-membered nitrogen-containing heterocycles were subsequently prepared via ring-closing metathesis of the dienes catalyzed by ruthenium benzylidene complex. 相似文献
29.
Solokha P De Negri S Skrobanska M Saccone A Pavlyuk V Proserpio DM 《Inorganic chemistry》2012,51(1):207-214
The synthesis, structural characterization, and chemical-bonding peculiarities of the two new polar lanthanum-magnesium germanides La(4)Mg(5)Ge(6) and La(4)Mg(7)Ge(6) are reported. The crystal structures of these intermetallics were determined by single-crystal X-ray diffraction analysis. The La(4)Mg(5)Ge(6) phase crystallizes in the orthorhombic Gd(4)Zn(5)Ge(6) structure type [Cmc2(1), oS60, Z = 4, a = 4.5030(7) ?, b = 20.085(3) ?, c = 16.207(3) ?, wR2 = 0.0451, 1470 F(2) values, 93 variables]. The La(4)Mg(7)Ge(6) phase represents a new structure type with a monoclinic unit cell [C2/m, mS34, Z = 2, a = 16.878(3) ?, b = 4.4702(9) ?, c = 12.660(3) ?, β = 122.25(3)°, wR2 = 0.0375, 1466 F(2) values, 54 variables]. Crystallographic analysis together with linear muffin-tin orbital band structure calculations reveals the presence of strongly bonded 3D polyanionic [Mg-Ge] networks balanced by positively charged La atoms in both stoichiometric compounds. The La(4)Mg(5)Ge(6) compound is related to Zintl phases, showing a prominent density of states pseudogap at the Fermi level. A distinctive feature of the La(4)Mg(5)Ge(6) structure is the presence of Ge-Ge covalent dumbbells; in La(4)Mg(7)Ge(6), the higher Mg content generates a polyanionic network consisting exclusively of Mg-Ge heterocontacts. Nevertheless, the frameworks of the two phases are structurally similar, as is highlighted in this work. 相似文献
30.
International Applied Mechanics - The problem of analysis of creep strains in thin-walled tubular elements made of linearly viscoelastic materials under uniaxial tension, pure torsion, and combined... 相似文献