Electric field induced nucleation is introduced as a possible mechanism to realize a metallic phase of hydrogen. Analytical expressions are derived for the nucleation probabilities of both thermal ...and quantum nucleation in terms of material parameters, temperature, and the applied field. Our results show that the insulator-metal transition can be driven by an electric field within a reasonable temperature range and at much lower pressures than the current paradigm of P > 400 GPa. Both static and oscillating fields are considered and practical implementations are discussed.
We present a theory of second phase conductive filaments in phase transformable systems; applications include threshold switches, phase change memory, and shunting in thin film structures. We show ...that the average filament parameters can be described thermodynamically. In agreement with the published data, the predicted filament current voltage characteristics exhibit negative differential resistance vanishing at high currents where the current density becomes a bulk material property. Our description is extendible to filament transients and allows for efficient numerical simulation.
•Mock-ups of the ITER tungsten divertor plate were tested with the combination of thermocyclic electron beam tests of up to 40 MW/m2 and subsequently with steady-state plasma of 0.5–1 MW/m2 in the ...PLM plasma device.•The tests led to erosion, cracking, and nanostructured “fuzz” growth on the tungsten surface.•The “fuzz” layer on tungsten surface was tested with the e-beam.
Mock-ups of the ITER divertor plate are tested with the combination of steady-state plasma and e-beam loads: (1) thermocyclic tests with powerful electron beam load of up to 49 MW/m2 in the e-beam facility; and then (2) subsequent testing in the PLM plasma device with steady-state plasma loads of 0.5–1 MW/m2 and more. Such tests simulate the variable load on divertor plates in the ITER. Tungsten samples are irradiated with helium plasma in experiments on the PLM plasma device with discharge duration of up to 200 min. The tests of ITER-grade tungsten VM-P with the combination of steady-state plasma and thermocyclic e-beam loads led to erosion, cracking, and nanostructured “fuzz” structure growth on the material surface. Post-mortem scanning electron microscopy revealed a stochastic nanostructured surface with dimension of structural elements less than 100 nm. The growth of a nanostructured surface with a “fuzz”-type structure and high porosity is observed. The results of such tests are of interest to estimate the erosion of tungsten in fusion reactors, including ITER, fusion neutron source FNS and DEMO.
Nuclear physics midterm plan at LNS De Filippo, E.; Nania, R.; Pizzone, R. G. ...
European physical journal plus,
11/2023, Letnik:
138, Številka:
11
Journal Article
Recenzirano
Odprti dostop
The next years will see the completion of several new facilities at Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud (LNS) opening up new possibilities in the fields of nuclear ...structure, nuclear dynamics, nuclear astrophysics and applications. These include a new line for high-intensity cyclotron beams, a new facility for in-flight production of radioactive ion beams, the PANDORA plasma trap for multidisciplinary studies and a high-power laser for basic science and applied physics. The nuclear physics community has organized a workshop to discuss the new physics opportunities that will be possible in the middle term (5–7 years) by employing state-of-the-art detection systems. A detailed discussion of the outcome from the workshop is presented in this report.
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•Surface reaction-driven current observed for decomposition of H2O2 on Pt and TiO2.•Surface phenomenon crucial in generation of H2O2 decomposition-induced current.•Conversion ...efficiency of 10−3 electrons generated per available H2O2 molecule observed.•Titanium oxidation state change generates electrons to diffuse through the metal oxide.
We report on conversion of energy released due to chemical reactions into current for the decomposition of aqueous hydrogen peroxide solution on single phases Pt and TiO2, in addition to Pt and TiO2 simultaneously. We observe that H2O2 decomposition-induced current on TiO2 drastically overshadows the current generated by H2O2 decomposition on Pt. Photo-effects avoided, H2O2 decomposition was found to yield a conversion efficiency of 10−3 electrons generated per H2O2 molecule. Further understanding of chemical reaction-induced current shows promise as a metric with which the surface reaction may be monitored and could be greatly extended into the field of analytical chemistry.
Electron beam induced effects in CdTe photovoltaics Harju, R.; Karpov, V.G.; Grecu, D. ...
Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036),
2000
Conference Proceeding
The authors used a SEM technique to measure in situ EBIC decay in CdTe photovoltaic cells. They have observed: (i) EBIC signal shows a considerable, continuous decay depending on the electron-beam ...current, scan area, energy, and sample treatment; (ii) the characteristic decay time differs considerably between samples of different recipes, some of them showing remarkable stability; and (iii) the decay rate fluctuates between different spots on the same sample. Their phenomenological model relates the observed decay to defects caused by radiation in semiconductor absorber layer.
A single-phase fcc high-entropy alloy (HEA) of 20%Cr-40%Fe-20%Mn-20%Ni composition and its strength with yttrium and zirconium oxides version was irradiated with 1.4 MeV Ar ions at room temperature ...and mid-range doses from 0.1 to 10 displacements per atom (dpa). Transmission electron microscopy (TEM), scanning transmission electron microscopy with energy dispersive X-ray spectrometry (STEM/EDS) and X-ray diffraction (XRD) were used to characterise the radiation defects and microstructural changes. Nanoindentation was used to measure the ion irradiation effect on hardening. In order to understand the irradiation effects in HEAs and to demonstrate their potential advantages, a comparison was performed with hardening behaviour of 316 austenitic stainless steel irradiated under an identical condition. It was shown that hardness increases with irradiation dose for all the materials studied, but this increase is lower in high-entropy alloys than in stainless steel.
This paper reports results from a study of two new genetic types of diamond discovered in Kamchatka. These diamonds were formed under extra-mantle conditions, as can be inferred from the fact that ...there is no indication of post-crystallization annealing with the formation of aggregated nitrogen defects in them. The first of these types is defined by us as volcanic-atmoelectrogenic. This is formed directly in a volcanic ash-gas cloud due to deep-seated methane released by atmospheric electric discharges. The second genetic type of diamonds is formed at depth within a magmatic-pneumatolytic-hydrothermal ore deposit, and can be defined as the explosive-tuffisite type. The industrial potential of these types enables us to assert the discovery of a new diamondiferous province, i.e., the Kamchatka Province.
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