The size dependence of the melting point of Si nanoparticles is investigated using molecular dynamics and thermodynamic simulation based on the Thomson’s formula. The atomistic modeling data obtained ...using the Stillinger–Weber potential agree with the results reported by other authors and thermodynamic-simulation data and predict a decrease in the melting point
T
m
of Si nanoparticles with an increase in their reciprocal radius
R
–1
according to linear law. The available experimental data predict lower
T
m
values, including the limiting value
, which corresponds to the linear extrapolation of experimental points to
R
–1
→ 0 (to the radius
R
→ ∞); the underestimation is 200–300 K as compared with the reference melting point of silicon (1688 K). It is concluded that the molecular-dynamics data on
T
m
(
R
–1
) obtained using the Stillinger–Weber potential are more adequate than the available experimental data.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Frequent acquisition of Synthetic Aperture Radar (SAR) data by the European Sentinel-1 satellites provides an opportunity for monitoring the dynamics of worldwide glaciers. We present a ...fully-automated processing system for producing multi-dimensional time series of glacier flow. We then use this fully-automated processing system to investigate the dynamics of Muldrow Glacier, located in the Denali National Park and Preserve (Alaska, AK, USA) during the October 2014—November 2021 period. We compute north, east, and vertical Surface-Parallel-Flow (SPF) and non-Surface-Parallel-Flow (nSPF) components of flow velocity and displacement with an average temporal resolution of 9 days and grid spacing of 100 m. During this period, we observe a glacier surge, a manifold increase in glacier flow velocity, that started as early as 2017 and continues until the present; however, the near completion of this surge is apparent. This glacier previously surged in 1906–1912 (the exact date is unknown) and in 1956–1957. We present our results in different ways to emphasize various aspects of the observed surge and demonstrate the full capability of our processing system. As the availability of SAR data improves, we expect that the fully-automated processing systems, similar to the one presented here, will play an increasingly dominant role and soon entirely replace manual processing.
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Experimental details are discussed and millimeter wave measurements presented of a W-band gyrotron traveling-wave tube (gyro-TWT) that uses a helically corrugated interac-tion waveguide operating at ...the second electron cyclotron har-monic. A method for increasing the gain by using an interaction circuit with two sections separated by a long sub-cutoff drift sec-tion has been experimentally verified. A 10-mW driving source was sufficient to enable an amplified signal output power of 3 kWs. The continuous-wave (CW) operation with a single-stage depressed collector and deposited beam power of about 20 kW is believed to be the first demonstration of its kind for a W-band gyro-TWT.
In this study, we describe a novel method for one-step cloning and targeted duplication of P. ananatis chromosomal fragments. According to this method, the chromosomal region of interest is subcloned ...in vivo via λ Red recombination into the short synthetic non-replicable DNA fragment containing the excisable antibiotic-resistance marker gene and φ80 att-P site. The resulting circular non-replicating DNA molecule was immediately inserted into an alternative chromosomal locus due to φ80-integrase activity. To this end, the specially designed helper plasmid pONI, which can provide both the λ Red recombineering and φ80-integrase-mediated insertion, was constructed. In the described method, PCR amplification of the cloning fragment is unnecessary, making it convenient for manipulation of long-length DNA. Additionally, the possibility of spontaneous mutations occurring is completely precluded. This method was effectively used for the targeted chromosomal integration of additional copies of individual genes and operons up to 16 kb in size.
•A method for one-step cloning of P. ananatis chromosomal fragments was developed.•This method includes PCR-free in vivo cloning of long DNA fragments of interest.•This recombineering-based method includes targeted integration into chromosome.•Targeted integration is provided by recombination system of the phage φ80.•This method was used for targeted duplication of DNA fragments up to 16 kb in size.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Investigation of properties of nuclear matter at extremely high temperature and/or extremely high baryon densities under laboratory conditions is one of the fundamental lines of research in ...high-energy physics. Throughout the past decades, such investigations have been performed in collisions of ultrarelativistic heavy ions in several experiments at modern accelerator complexes, including the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL, USA) and the Large Hadron Collider (LHC) at CERN (Switzerland). In the near future, it is also planned to launch investigations of this kind at the FAIR (Facility for Antiproton and Ion Research at Gesellschaft für Schwerionenforschung (GSI), Darmstadt, Germany) and NICA (Nuclotron-based Ion Collider fAcility at Joint Institute for Nuclear Research (JINR), Dubna, Russia) accelerators. In order to implement such investigations, it is necessary to create sophisticated detector systems that are able to record events featuring high-multiplicity product particles and to measure reliably their properties. The present article gives a brief survey of all detector systems that have already been created and are being developed at Laboratory of Relativistic Nuclear Physics at Petersburg Nuclear Physics Institute (National Research Center Kurchatov Institute) for the PHENIX (BNL, USA), ALICE (CERN, Switzerland), and CBM (GSI, Germany) experiments aimed at studying nuclear matter under extreme conditions.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A complex approach based on thermodynamic and atomistic simulations is used to predict segregation in binary metal nanoparticles of Cu–Ni and Ag–Au. The results of thermodynamic simulation within the ...model of limited source of segregating component agree with those of the atomistic simulation, and both predict the surface segregation of Cu atoms in the Cu–Ni nanoalloys and the segregation of Ag atoms at the surface of the binary Ag–Au nanoparticles.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Fluctuations of energy egr;E in the canonical ensemble and of temperature egr;T in the micro-canonical one have been evaluated theoretically as well as employing the isothermal and adiabatic ...molecular dynamics (MD), respectively. MD experiments were performed on Au NPs in the size range from 1.0 to 15.0 nm. As secondary results, MD data on the temperature dependence of the heat capacity of Au NPs are also obtained and analyzed. Theoretical evaluations of egr;E and egr;T satisfactory or, in some cases, very well agree with our MD results on Au NPs. We have found that egr;T is by about two orders of magnitude higher than egr;E. However, even for very small NPs (nanoclusters) consisting of 55 atoms egr;T is of order of 10 % only. So, a conclusion is made on applicability of both the Gibbs ensemble method and the notion of temperature in its conventional sense to NPs.
La Palma, Canary Islands, underwent volcanic unrest which culminated in its largest historical eruption. We study this unrest along 2021 using Interferometric Synthetic Aperture Radar (InSAR) and a ...new improved interpretation methodology, comparing achieved results with the crustal structure. We reproduce the final phase of La Palma volcanic unrest, highligthing a shallow magma accumulation which begins about 3.5 months before the eruption in a crustal volume charactherized by low density and fractured rocks. Our modeling, together with our improved pictures of the crustal structure, allows us to explain the location and characteristics of the eruption and to detect failed eruption paths. These can be used to explain post-eruptive phenomena and hazards to the local population, such as detected gases anomalies in La Bombilla and Puerto Naos. Our results have implications for understanding volcanic activity in the Canaries and volcano monitoring elsewhere, helping to support decision-making and providing significant insights into urban and infrastructure planning in volcanic areas.
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La Palma island is one of the highest potential risks in the volcanic archipelago of the Canaries and therefore it is important to carry out an in-depth study to define its state of unrest. This has ...been accomplished through the use of satellite radar observations and an original state-of-the-art interpretation technique. Here we show the detection of the onset of volcanic unrest on La Palma island, most likely decades before a potential eruption. We study its current evolution seeing the spatial and temporal changing nature of activity at this potentially dangerous volcano at unprecedented spatial resolutions and long time scales, providing insights into the dynamic nature of the associated volcanic hazard. The geodetic techniques employed here allow tracking of the fluid migration induced by magma injection at depth and identifying the existence of dislocation sources below Cumbre Vieja volcano which could be associated with a future flank failure. Therefore they should continue being monitored using these and other techniques. The results have implications for the monitoring of steep-sided volcanoes at oceanic islands.
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