Search for asymptotic Balitsky–Fadin–Kuraev–Lipatov (BFKL) effects at CMS in dijet events with large rapidity separation between jets in proton-proton collisions at 7 TeV is presented. CMS data on ...cross-section ratios and azimuthal decorrelations for dijets with large rapidity separation between jets are compared with predictions by various Monte Carlo (MC) event generators based on Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) and BFKL evolutions. None of DGLAP-based generators can describe all measured observable by CMS at 7 TeV. NLL BFKL predictions are consistent with CMS data on dijet azimuthal decorrelations at 7 TeV. More data at higher LHC energies are needed to reveal possible effects.
The article gives methodical guidelines for calculating hourly and daily outputs of bucket chain dredges. The improved output determination procedure is a chain of calculations of dredge performance ...in correlation with strength characteristics of rocks and with their depth- and width-varied properties. It is proposed to group the mining time and to take into account the action time losses connected with face cutting, dredging within the placer limits, and with breaks for the auxiliary operations. The delays are included via the introduced face cutting factor. It is found how the technical capacity of dredge, the face cutting factor and the dredge utilization per day change as function of the face width at different thickness of placers. The authors put forward an empirical equation for the technical dredge capacity.
Polymineral aggregates of rounded shapes (“nodules”) composed of native and sulfide minerals of Cu, Ni, Fe, Ag, and other elements from vein magnetite–calcite–chrysotile rocks with jewelry demantoid ...in the Korkodinskoe hypermafic massif are described. A common feature of the six identified types of native sulfide nodules, composed of native copper, heazlewoodite, pentlandite, cuprite, and other native sulfide minerals, is their spheroidal shape, which makes them similar to individual grains of other gangue minerals (calcite, magnetite, etc.). In heazlewoodite–pentlandite nodules, specific symplectites of mercuric silver and nickel copper in heazlewoodite, as well as awaruite in Co–pentlandite, were found. The matching set of ore minerals in the host serpentinite vein mass (native copper, mercuric silver, heazlewoodite, pentlandite, awaruite) and nodules from the vein material indicates their genetic connection and the conjugation of demantoid mineralization with the evolving processes of serpentinization. It was established that the nodules formed at temperatures below 380°C under reducing conditions at very low sulfur fugacity values (10
–17
–10
–27
bar) and oxygen (10
–30
bar at 200°C to 10
–21
bar at 350°C). For heazlewoodite–pentlandite nodules, such conditions persisted throughout the entire time of their formation, while, for other nodules, the reducing conditions of early parageneses were replaced by oxidative conditions in late parageneses, which is recorded by the replacement of native copper with cuprite. It is assumed that the features of the morphology and structure of native sulfide nodules and the presence of symplectite intergrowths of ore minerals in them are associated with specific conditions created during the decompression of the crust-mantle mixture rising to the surface in the fault zone. The source of the metals was a deep, high-temperature fluid interacting with mafic and ultramafic rocks under reducing conditions at a low water-to-rock ratio.
This paper reviews and summarizes the available information on the composition of palladian gold with various contents and sets of isomorphic impurities (Ag, Cu, Hg) at 50 deposits and ore ...occurrences with Au-Pd mineralization. It is revealed that Palladian gold is represented by the systems Au–Pd, Au–Pd–Hg, Au–Pd–Cu, and Au–Pd–Ag–Hg, but more frequently corresponds to Au–Pd–Ag, Au–Pd–Ag–Cu, and Au–Pd–Ag–Cu–Hg. Objects with palladian gold belong to different types of gold deposits and to the deposits at which the main components of ores are PGE, Cr, Cu, Ni, V, and Ti. We propose a classification of the types of deposits with palladian gold: (1) PGE ore deposits related to mafic–ultramafic magmatic complexes (two subtypes—(a) low-sulfide-grade (less than 2%–5% sulfides) Alaskan, and (b) high-sulfide-grade (more than 5% sulfides) Norilsk); (2) orogenic gold deposits (OG); (3) epithermal (porphyry) gold–copper deposits (EPGC); (4) iron oxide copper gold deposits (IOCG); (5) ferruginous quartzite deposits; (6) volcanic exhalation; and (7) gold-PGE placers of five subtypes corresponding to the types of 1–5 primary sources. Physicochemical conditions of the formation of palladian gold at some deposits of type 1 cover two areas—magmatic high-temperature and hydrothermal low-temperature. At the majority of deposits of types 2–4, its formation proceeds with the participation of hydrothermal fluids (300–60 °C) of various salinities (0.2–30 wt.% NaCl eq.). Palladian gold is mainly high-fineness (910‰–990‰), is less frequently medium-fineness, and contains Ag and Cu, but does not contain Hg at the deposits of types 1, 3, and 4. The only exception is the Au-Pd-Hg Itchayvayam ore occurrence (Kamchatka, Russia), for which two varieties of Pd,Hg-bearing native gold (fineness 816‰–960‰ and 580‰–660‰) are determined. Low-fineness palladian gold with the major content of Ag is typical of OGD deposits. Medium-fineness palladian gold occurs at ferruginous quartzite deposits and in volcanic exhalations. Hg, Ag, Cu-bearing high-fineness palladian gold is present mainly in placer deposits (type 7). The most common minerals in association with palladian gold are arsenides, stibioarsenides, sulfides, stannides, bismuthides, tellurides, and selenides of Pd and Pt. These are typical of deposit types 1 and 7. The minerals of Au, Ag, and Cu (tetra-auricupride, aurostibite, chalcopyrite, bornite, chalcocite, eucairite, etc.) are in association with palladian gold at OG, EPGC, and IOCG deposits. Hg minerals (cinnabar, tiemannite, coloradoite, potarite) are at some deposits (types 1, 2, 7-1, 7-4). Cu, Fe, and Pd oxides (tenorite, hematite, magnetite, PdO, (Pd,Cu)O) and Fe and Pd hydroxides (goethite, (Fe,Pd)OOH) occur at the deposits of the 3, 4, and 7 groups and indicate the highly oxidizing conditions of ore formation. The most common minerals among host minerals are quartz and muscovite, including fuchsite (Cr-Ms), chlorite, albite, K-feldspar, hornblende, and carbonates (calcite, siderite, etc.). The fineness, content, and set of impurities in palladian gold and minerals in association with it reflect the mineralogy of Au-Pd ores and allow them to be used as indicators for the deposit types.
Magnetoplasmonic crystals consisted of the combination of noble and ferromagnetic thin films deposited on diffraction gratings represent a special class of nanostructures that can utilize the ...magneto-optical Kerr effect enhanced by surface plasmon-polaritons excitation for the probing of an external DC magnetic field. Optical and magneto-optical properties of a magnetoplasmonic crystal are formed by magnetic behavior. This article represents ways to manipulate optical, magneto-optical and magnetic properties of nickel-based magnetoplasmonic crystals by the variation of the substrate parameters, the composition of magnetoplasmonic crystals as well as the compressive mechanical stresses on the surface of a ferromagnetic layer.
Research results of a influence spot diameter and laser radiation transversal oscillation amplitude on the quality formation of the built-up layers at the direct laser deposition is described in the ...publication. Productivity of the direct laser deposition and quality formation thin wall were increased using research results.
Miniature magnetic sensors based on magnetoplasmonic crystals (MPlCs) exhibit high sensitivity and high spatial resolution, which can be obtained by the excitation of surface plasmon polaritons. A ...field dependence of surface plasmon polaritons' enhanced magneto-optical response strongly correlates with magnetic properties of MPlCs that can be tuned by changing spatial parameters, such as the period and height of diffraction gratings and thicknesses of functional layers. This work compares the magnetic properties of MPlCs based on Ni80Fe20 (permalloy) obtained from local (longitudinal magneto-optical Kerr effect) and bulk (vibrating-sample magnetometry) measurements and demonstrates an ability to control sensors' performance through changing the magnetic properties of the MPlCs. The influence of the substrate's geometry (planar or sinusoidal and trapezoidal diffraction grating profiles) and the thickness of the surface layer is examined.
We studied powder samples of europium titanates Eu1−x2+Eux3+TiO3+x/2 prepared by sol-gel and coprecipitation methods with subsequent thermal treatment of precursors at different conditions (reducing ...or oxidizing atmosphere, temperature, exposure time). We have revealed a radical rearrangement in the local, electronic and crystal structure of europium titanates depending on synthesis conditions. The combination of synchrotron X-ray diffraction (s-XRD), X-ray absorption (XANES and EXAFS), infrared and Raman spectroscopies supplemented by photoluminescence and simultaneous thermal analysis was used in our study. It is shown that the combined XANES and thermogravimetric analysis gives clear evidence of a change in the oxidation state of europium cations from Eu2+ to Eu3+. The comparison of s-XRD, XANES, and EXAFS data allowed us to explain the local structure rearrangement during the phase transition from cubic perovskite Eu2+TiO3 (space group Pm3¯m) to pyrochlore phase Eu23+Ti2O7 (space group Fd3¯m) through intermediate layered perovskite Eu23+Ti2O7 with monoclinic structure (space group P21) under annealing in oxidizing atmosphere. The Raman spectroscopy study pointed to significant changes in the local structure of the anionic sublattice upon the observed phase transitions. The analysis of luminescence spectra has shown that Eu3+ cations occupy positions with low local site symmetry in all synthesized compounds regardless of the type of the crystal structure.
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•Local, electronic and crystal structure rearrangement in Eu titanates was studied.•s-XRD, XAFS, IR, Raman spectroscopy, TGA and PL methods were used.•XANES and TGA are effective tools for determining the Eu2+/Eu3+ cations ratio.•Eu3+ cations occupy low local site symmetry positions in synthesized compounds.
The deflection of a 1-GeV proton beam by a bent silicon crystal 1 mm long by an angle of (3.0 ± 0.1) mrad with an efficiency of (32 ± 3)% for end-face capture into the channeling regime has been ...observed for the first time in the presented experiment. The developed crystal deflector makes it possible to increase the beam deflection angle and can be used to produce low-intensity beams at intermediate energies.
Micro/mesoporous materials with different contribution of micro- and mesoporosity were prepared by recrystallization of zeolite BEA in alkaline solution in the presence of cethyltrimethylammonium ...bromide. The materials were characterized by XRD, nitrogen adsorption–desorption and IR spectroscopy of adsorbed probe molecules. It has been demonstrated that the degree of recrystallization can be adjusted by variation of concentration of NaOH in solution. Recrystallization in mild conditions did not significantly affect the amount and strength of acid sites but resulted in the improvement of their accessibility for bulky probe molecules due to the creation of mesopores. The increase of the degree of recrystallization led first to partial and then to complete transformation of BEA into MCM-41 followed by a gradual decrease of the amount and strength of Brønsted sites and the increase of the contribution of Lewis sites to the total amount of sites.
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