Target system for the CC-series сyclotrons designed and manufactured in NIIEFA

A prototype of the target system for the CC-series cyclotrons for production of PET radionuclides C-11 and F-18 has been designed, manufactured and tested in the Efremov Institute. The target system will produce radionuclides sufficient to ensure the needs of a standard PET-center.У НДІЕФА ім. Д.В. Єфремова розроблений, виготовлений і випробуваний дослідний зразок мішеневого комплексу циклотронів серії СС для виробництва ПЕТ-радіонуклідів вуглець-11 і фтор-18. За продуктивностю напрацювання радіонуклідів комплекс забезпечить потреби типового ПЕТ-центру.В НИИЭФА им. Д.В. Ефремова разработан, изготовлен и испытан опытный образец мишенного комплекса циклотронов серии СС для производства ПЭТ-радионуклидов углерод-11 и фтор-18. По производительности наработки радионуклидов комплекс обеспечит потребности типового ПЭТ-центра

Search for electroweak production of single top quarks in ppˉp\bar{p} collisions.

We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb. (arXiv

Helicity of the W Boson in Lepton+Jets ttbar Events

We examine properties of ttbar candidates events in lepton+jets final states to establish the helicities of the W bosons in t->W+b decays. Our analysis is based on a direct calculation of a probability that each event corresponds to a ttbar final state, as a function of the helicity of the W boson. We use the 125 events/pb sample of data collected by the DO experiment during Run I of the Fermilab Tevatron collider at sqrt{s}=1.8 TeV, and obtain a longitudinal helicity fraction of F_0=0.56+/-0.31, which is consistent with the prediction of F_0=0.70 from the standard model

Hard Single Diffraction in pbarp Collisions at root-s = 630 and 1800 GeV

Using the D0 detector, we have studied events produced in proton-antiproton collisions that contain large forward regions with very little energy deposition (``rapidity gaps'') and concurrent jet production at center-of-mass energies of root-s = 630 and 1800 Gev. The fractions of forward and central jet events associated with such rapidity gaps are measured and compared to predictions from Monte Carlo models. For hard diffractive candidate events, we use the calorimeter to extract the fractional momentum loss of the scattered protons.Comment: 11 pages 4 figures. submitted to PR

2,3,4,5-Tetraiodopyrrole as a building block for halogen bonding: Formation of supramolecular hybrids with organic iodide salts in solid state

Reactions of tri(n-propyl)ammonium (1) or 1,3,5-trimethylpyridinium (2) iodides with 2,3,4,5-tetraiodopyrrole (TIP) results in formation of hybrids CatI•TIP•xEtOH (X = 0.5 (1) and 0.33 (2), respectively) which feature strong halogen bonding (XB) between I atoms of TIP and iodide anions. DFT calculations reveal that XB energies are up to 4.3 kcal/mol

Heteroleptic Zn(II) 3,5-diiodosalicylates: Structures, luminescence and features of non-covalent interactions in solid state

Heteroleptic Zn(II) 3,5-iodosalicylate (DISA) complexes of general formula [Py2ZnDISA2] (Py = 3-methyl (1), 4-methyl (2), 3,5-dimethyl (3), 3,4-dimethyl (4) and 3-bromopyridine (5), respectively) were prepared and characterized by X-ray diffractometry and thermogravimetric analysis. All complexes demonstrate luminescence in blue region with quantum yields varying in 1.45–2.6% range

New oxidovanadium(IV) complexes with 2,2′-bipyridine and 1,10-phenathroline ligands: Synthesis, structure and high catalytic activity in oxidations of alkanes and alcohols with peroxides

Reactions of [VCl 3 (thf) 3 ] or VBr 3 with 2,2′-bipyridine (bpy) or 1,10‐-phenanthroline (phen) in a 1:1 molar ratio in air under solventothermal conditions has afforded polymeric oxidovanadium(IV) four complexes 1‒4 of a general formula [VO(L)X 2 ] n (L = bpy, phen and X = Cl, Br). Monomeric complex [VO(DMF)(phen)Br 2 ] (4a) has been obtained by the treatment of compound 4 with DMF. The complexes were characterized by IR spectroscopy and elemental analysis. The crystal structures of 3 and 4a were determined by an X‐-ray diffraction (XRD) analysis. The {VOBr 2 (bpy)} fragments in 3 form infinite chains due to the V = O…V interactions. The vanadium atom has a distorted octahedral coordination environment. Complexes 1‒4 have been tested as catalysts in the homogeneous oxidation of alkanes (to produce corresponding alkyl hydroperoxides which can be easily reduced to alcohols by PPh 3 ) and alcohols (to corresponding ketones) with H 2 O 2 or tert‐-butyl hydroperoxide in MeCN. Compound 1 exhibited the highest activity. The mechanism of alkane oxidation was established using experimental selectivity and kinetic data and theoretical DFT calculations. The mechanism is of the Fenton type involving the generation of HO • radicals. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Formation of bulk nanostructure metals under dynamic loading

Structural changes observed in samples of technical-purity titanium, copper, and aluminum alloy AMts (Al–Mn) after severe plastic deformation were studied and results of this investigation are presented. In experiments, materials were loaded with the help of a gun. Samples were accelerated up to the velocity of about 100–400 m/s and then directed into a special matrix consisting of two channels located at 90° to one another. These samples were deformed with the strain rate of ~ 105 s−1; the stagnation pressure in the channel ranged from 2 to 5 GPa. Consideration is given to the relation between loading conditions and the specific nature of structure formation in materials. Under dynamic loading, the coarse-grained structure of the grain in the aluminum alloy becomes ~ 400 nm, and the sub-grain structure with the size of 50–100 nm is formed in copper. Microhardness of materials increases 1.5–2 times