Interconnection between parameters of rock samples electromagnetic signals and content of magnetite in the samples

The paper describes the results of studies of electromagnetic response parameters of samples of bearing strata and ore rocks from the Tashtagol mine on acoustic effects. Patterns of changes in amplitude-frequency parameters of electromagnetic signals for rock samples with different content of magnetite are experimentally found. The conducted research shows that the maximum amplitudes of electromagnetic signal spectral components increases in samples of the same mineral composition with the reduction of their ultimate strength. This is caused by heterogeneities, and defective areas which contribute to active transformation of mechanical energy into electromagnetic energy. For rocks, which contain magnetite, the emissivity depends not only on heterogeneities and defective areas, but on the quantity of high-conductivity minerals in their composition

Assemblathon 2: evaluating de novo methods of genome assembly in three vertebrate species

Background: The process of generating raw genome sequence data continues to become cheaper, faster, and more accurate. However, assembly of such data into high-quality, finished genome sequences remains challenging. Many genome assembly tools are available, but they differ greatly in terms of their performance (speed, scalability, hardware requirements, acceptance of newer read technologies) and in their final output (composition of assembled sequence). More importantly, it remains largely unclear how to best assess the quality of assembled genome sequences. The Assemblathon competitions are intended to assess current state-of-the-art methods in genome assembly. Results: In Assemblathon 2, we provided a variety of sequence data to be assembled for three vertebrate species (a bird, a fish, and snake). This resulted in a total of 43 submitted assemblies from 21 participating teams. We evaluated these assemblies using a combination of optical map data, Fosmid sequences, and several statistical methods. From over 100 different metrics, we chose ten key measures by which to assess the overall quality of the assemblies. Conclusions: Many current genome assemblers produced useful assemblies, containing a significant representation of their genes and overall genome structure. However, the high degree of variability between the entries suggests that there is still much room for improvement in the field of genome assembly and that approaches which work well in assembling the genome of one species may not necessarily work well for another

Proof-of-Principle Experiment for FEL-Based Coherent Electron Cooling,”

Abstract Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, highintensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC

Optical magnetic mirror

We report demonstration of an optical magnetic mirror achieved by nanostructuring a metal surface. In contrast to normal mirrors, it inflicts only small change to the phase of a reflected wave, offering intriguing applications

Magnetic mirror on optical frequency

We report demonstration of an optical magnetic mirror achieved by nanostructuring a metal surface. In contrast to normal mirrors, it inflicts only small change to the phase of a reflected wave, offering intriguing applications.<br/

A robust CoxMg1-xO catalyst for predominantly growing (6,5) single-walled carbon nanotubes

Chirality-controlled growth of single-walled carbon nanotubes (SWCNTs) by chemical vapor deposition (CVD) is one of the most challenging tasks in carbon nanotube synthesis field. During CVD growth, the catalyst plays crucial roles in governing SWCNT nucleation thermodynamics as well as growth kinetics. However, the performances of catalyst are generally sensitive to the metal loading amount in the catalyst and the reaction conditions, like the partial pressure of carbon source and the reaction time. In this work, we have systematically investigated a robust CoxMg1-xO solid solution, which can predominantly yield (6, 5) SWCNTs in a wide range of Co concentration, with a diversity of CO concentrations or a broad-ranging reaction time. Besides, the effect of reaction temperature on SWCNT chirality distribution is demonstrated, the mechanism of which is clarified with the assistance of environmental transmission electron microscopy. Finally, the chirality distribution of SWCNTs grown using CH4 as the carbon source is presented. The effects of carbon sources are discussed in view of SWCNT growth mode. (C) 2019 Elsevier Ltd. All rights reserved

Manufacturing of Metal&ndash;Diamond Composites with High-Strength CoCrCuxFeNi High-Entropy Alloy Used as a Binder

This paper focuses on the study of the structure and mechanical properties of CoCrCuxFeNi high-entropy alloys and their adhesion to single diamond crystals. CoCrCuxFeNi alloys were manufactured by the powder metallurgy route, specifically via mechanical alloying of elemental powders, followed by hot pressing. The addition of copper led to the formation of a dual-phase FCC + FCC2 structure. The CoCrCu0.5FeNi alloy exhibited the highest ultimate tensile strength (1080 MPa). Reductions in the ductility of the CoCrCuxFeNi HEAs and the tendency for brittle fracture behavior were observed at high copper concentrations. The equiatomic alloys CoCrFeNi and CoCrCuFeNi demonstrated high adhesion strength to single diamond crystals. The diamond surface at the fracture of the composites having the CoCrFeNi matrix had chromium-rich metal matrix regions, thus indicating that chromium carbide, responsible for adhesion, was formed at the composite&ndash;diamond interface. Copper-rich areas were detected on the diamond surface within the composites having the CoCrCuFeNi matrix due to the predominant precipitation of the FCC2 phase at the interfaces or the crack propagation along the FCC/FCC2 interface, resulting in the exposure of the Cu-rich FCC2 phase on the surface

Manufacturing of Metal–Diamond Composites with High-Strength CoCrCu_xFeNi High-Entropy Alloy Used as a Binder

This paper focuses on the study of the structure and mechanical properties of CoCrCuxFeNi high-entropy alloys and their adhesion to single diamond crystals. CoCrCuxFeNi alloys were manufactured by the powder metallurgy route, specifically via mechanical alloying of elemental powders, followed by hot pressing. The addition of copper led to the formation of a dual-phase FCC + FCC2 structure. The CoCrCu0.5FeNi alloy exhibited the highest ultimate tensile strength (1080 MPa). Reductions in the ductility of the CoCrCuxFeNi HEAs and the tendency for brittle fracture behavior were observed at high copper concentrations. The equiatomic alloys CoCrFeNi and CoCrCuFeNi demonstrated high adhesion strength to single diamond crystals. The diamond surface at the fracture of the composites having the CoCrFeNi matrix had chromium-rich metal matrix regions, thus indicating that chromium carbide, responsible for adhesion, was formed at the composite–diamond interface. Copper-rich areas were detected on the diamond surface within the composites having the CoCrCuFeNi matrix due to the predominant precipitation of the FCC2 phase at the interfaces or the crack propagation along the FCC/FCC2 interface, resulting in the exposure of the Cu-rich FCC2 phase on the surface

Magnetic nanoribbons with embedded cobalt grown inside single-walled carbon nanotubes

Molecular magnetism and specifically magnetic molecules have recently gained plenty of attention as key elements for quantum technologies, information processing, and spintronics. Transition to the nanoscale and implementation of ordered structures with defined parameters is crucial for advanced applications. Single-walled carbon nanotubes (SWCNTs) provide natural one-dimensional confinement that can be implemented for encapsulation, nanosynthesis, and polymerization of molecules into nanoribbons. Recently, the formation of atomically precise graphene nanoribbons inside SWCNTs has been reported. However, there have been only a limited amount of approaches to form ordered magnetic structures inside the nanotube channels and the creation of magnetic nanoribbons is still lacking. In this work we synthesize and reveal the properties of cobalt-phthalocyanine based nanoribbons (CoPcNRs) encapsulated in SWCNTs. Raman spectroscopy, transmission electron microscopy, absorption spectroscopy, and density functional theory calculations allowed us to confirm the encapsulation and to reveal the specific fingerprints of CoPcNRs. The magnetic properties were studied by transverse magnetooptical Kerr effect measurements, which indicated a strong difference in comparison with the pristine unfilled SWCNTs due to the impact of Co incorporated atoms. We anticipate that this approach of polymerization of encapsulated magnetic molecules inside SWCNTs will result in a diverse class of protected low-dimensional ordered magnetic materials for various applications