This paper develops a cross-scale dual-heat-source coupled model to tackle the difficulty of forecasting nonlinear thermal effects in microbubble-enhanced high-intensity focused ultrasound, encompassing both microscopic single-bubble dynamics and macroscopic biological heat transfer. The model utilizes the Keller–Miksis equation, which includes liquid compressibility, to precisely measure the mechanical work produced by microbubble collapse. A novel approach is also developed to employ a dynamic nonlinear negative feedback mechanism that is triggered by tissue coagulative necrosis. This mechanism is called "acoustic attenuation jump" and "hardening-induced cavitation inhibition." The research indicates that the substantial mechanical work generated by extreme inertial collapse (temporary high temperature of around 5000 K) is the catalyst for the "thermal sting effect." The dynamic negative feedback quickly cuts off the cavitation heat source, keeping the peak temperature at about 81°C. This fixes the static model's serious error of overestimating the amount of damage caused by heat diffusion (by about 89.7%). Also, optimizing the parameters showed that the energy efficiency factor follows a nonlinear 'U-shaped' law, which means that the best duty cycle is about 42%. Two-dimensional acoustic field simulation validated that dynamic feedback efficiently mitigated hazardous axial thermal dispersion and target forward displacement. This study establishes a robust theoretical framework for accurate dose planning and the delineation of a safe operational range for microbubble-enhanced high-intensity focused ultrasound.
The ab initio study was performed using the generalized gradient approximations implemented in the CASTEP code to investigate the impact of vanadium doping on the electronic, optical, and magnetic properties of HgTe. The calculated lattice parameters of the compound under ambient conditions showed good agreement with experimental data. The pure HgTe compound is a semimetal, with the higher energy states of the valence band overlapping only the lower energy states of the conduction band. Doping with vanadium (V) induces ferromagnetism in the system, leading to a significant spin polarization of about 90% at the Fermi surface, making HgTe a potential candidate for spintronic applications. The Curie temperature (TC) was estimated using mean field theory for doping concentrations of 12% and 24%. The double exchange is suggested as the most responsible interaction of ferromagnetism in the system. Optical calculations indicate enhanced absorption in the visible and infrared regions, suggesting its viability for optoelectronic device applications. These findings pave the way for the design of transition-metal-doped HgTe for the technological advancement of spintronics and photonics in the future.
Understanding the oxidation state of sulphur in fine atmospheric particulate matter (PM2.5) is essential for constraining secondary aerosol formation, climate forcing, and health impacts. This study utilises comparison of sulphur K-edge X-ray absorption near-edge structure spectra, combined with linear combination fitting of reference spectra, to characterise sulphur speciation in PM2.5 from Kraków (Poland), Qingdao (China), and Atlanta (USA). Across all regions, sulphate species S(+6) dominate, confirming their role as the principal end product of atmospheric sulphur oxidation, but the distribution of intermediate and reduced sulphur forms varies systematically with emission sources and meteorological conditions. In Kraków, wintertime PM2.5 is richer in ammonium bisulphates relative to summer, consistent with enhanced solid-fuel combustion and more acidic aerosol conditions. In Qingdao, coarse particles contain detectable S(+4) species associated with gypsum and calcium sulphite, linked to interactions between anthropogenic sulphur and mineral dust, whereas fine particles are dominated by ammonium sulphate. In the Atlanta region, ammonium sulphate is prevalent at all sites, with additional contributions from gypsum and metal-containing sulphates that vary between urban, rural, and background locations. Based on literature data employing a consistent spectroscopic methodology for a specific region across three contrasting environments, this study identifies region-specific sulphur speciation fingerprints and demonstrates the capability of X-ray absorption near-edge structure to link emission inventories, atmospheric transformation processes, and policy-relevant indicators of aerosol composition.
Synchrotron radiation facilities offer intense and tunable X-ray beams, enabling time-efficient acquisition of X-ray absorption spectra, such as X-ray absorption near-edge structure and extended X-ray absorption fine structure, with temporal resolution comparable to the characteristic timescales of structural transformations, including crystallization processes in glasses. In this work, we present the design and implementation of a high-temperature sample holder developed for the ASTRA beamline at the SOLARIS Synchrotron in Kraków, Poland. The holder supports in situ and operando X-ray absorption spectroscopy experiments in both transmission and fluorescence detection modes at temperatures up to 500°C. Its performance was validated through temperature-dependent X-ray absorption spectroscopy measurements of binary vanadate–phosphate glasses undergoing crystallization. The preliminary results confirm the stability, reliability, and applicability of the setup for tracking thermally induced structural changes in solid-state materials using absorption spectroscopy.
This article presents the initial results of in-situ high-temperature X-ray absorption spectroscopy measurements using hard X-ray radiation of oxygen electrodes of solid oxide cells. The ability to perform in-situ measurements, i.e., under conditions close to those of real operation, enables the acquisition of unique information on the behaviour of the material, providing a deeper understanding of the operating mechanisms of the electrodes, which can guide their further development. Praseodymium oxide (PrOx) was selected as a promising material with potential applications in low-temperature solid oxide cells. The average oxidation state of praseodymium in a 100 nm PrOx film has been shown to decrease from 3.49+ at room temperature to 3.06+ at 400°C. These results emphasise the importance of using thin films and highlight the processes occurring at the interface between the electrolyte (ionic conductor) and the oxygen electrode. The studies presented here lay the groundwork for further development in this area of high-temperature measurements, with the goal of establishing operando measurement methodology.
This study establishes a comprehensive, sequential multimodal workflow for archaeometric analysis of medieval ceramics, integrating seven measurement techniques to characterize elemental, crystalline, amorphous, microstructural, structural, and chemical-state properties of the material, while preserving artefact integrity. Therefore, (i) X-ray fluorescence establishes baseline major (Si, Al, Fe, Ca, K, Na) and trace (Cr, Mn, Zr) profiles for paste discrimination; (ii) X-ray diffraction identifies kaliophilite/oligoclase phases (~ 800–900°C firing); (iii) Fourier transform infrared resolves amorphous networks (Si–O–Si 950–1100 cm-1); (iv) Raman spectroscopy detects microscale oxide impurities (anatase TiO2 lattice modes at 110–160 cm-1, ZrO2, Al2O3 corundum M–O stretching modes at 440–465 cm-1) and lattice defects, revealing heavy mineral tempers (rutile sands) and refractory phases undetectable by bulk diffraction analysis or the broad spectral envelopes of infrared spectroscopy; (v) scanning electron microscope with energy dispersive spectroscopy quantifies temper distributions; (vi) X-ray computed tomography reveals 3D void networks, and (vii) X-ray absorption near-edge structure constrains speciation of Fe2+/Fe3+, Ca carbonate–silicates, and K-feldspars. This standardized framework enables precise reconstruction of provenance, fluxing strategies, pyrotechnology, and post-firing alterations, beyond the limitations of single- and dual-technique approaches, providing a reproducible protocol for heritage science.
The present paper provides a short review of the magnetocaloric effect and selected magnetocaloric materials, such as Gd-based alloys, MnCoGe alloys, and La(Fe, Si)13-type alloys. The magnetocaloric effect is a fundamental environmentally friendly technique for lowering temperature, which is nowadays highly developed due to its potential application in domestic refrigerators or heat pumps. This article delivers information on the theory of the magnetocaloric effect. Moreover, it reviews the structure and thermomagnetic properties of selected materials suitable for active magnetic regenerators working at close to room temperature.
Perovskite materials with the general formula ABX3 have attracted considerable interest due to their broad potential in applications such as optoelectronics, solar energy conversion, and catalysis. In this study, the fluoroperovskite compound TlSrF3 is theoretically investigated for its suitability for scintillation detector applications. A comprehensive analysis of its structural, electronic, optical, and thermodynamic properties was conducted using density functional theory. The results reveal that TlSrF3 confirms a stable cubic perovskite phase with the space group Pm-3m (no. 221). The calculated electronic band structure and density of states reveal a direct, wide band gap of approximately 4.40 eV at a high-symmetry point in the Brillouin zone, indicative of strong insulating behavior. Optical properties analyzed over the photon energy range of 0–14 eV show high isotropy between the εxx and εzz components, significant ultraviolet absorption, and excellent transparency in the visible region — key features for scintillation detection. Thermodynamic stability across wide temperature and pressure ranges is confirmed via the GIBBS2 code calculations. In the absence of experimental data, these theoretical insights offer a reliable foundation for future experimental validation and device-level integration. This work confirms the potential of fluoroperovskites as functional materials in advanced detection and energy technologies.
The weakly nonlinear propagation of a random surface wave over a water region of varying depth h is considered. A random, stationary Gaussian process describing perturbations in the volume of the liquid is assumed at infinite depth. The characteristics of the nonlinear random wave are evaluated as the wave propagates into shallow coastal waters. It is found that the mean amplitude of the fundamental harmonic of the wave is proportional to h7/8, while its variance is proportional to h7/4 as the wave approaches the coastal zone. The mean amplitude of the second harmonic is proportional to h-1/4. Manifestation of nonlinear effects becomes abrupt when the water depth falls below a certain critical value. This behavior occurs for relatively small energy densities of the perturbation at infinite depth, as specified in the study. For larger energy densities, nonlinear effects increase gradually.
Cryo-electron microscopy has emerged as a transformative technique in structural biology, enabling the high-resolution structural determination of large and heterogeneous biological assemblies. This review highlights recent advances in understanding the structural and functional diversity of protein cages, ribonucleic acid molecules and complexes, as well as enzyme complexes, as revealed by cryo-electron microscopy. We discuss how cryo-electron microscopy provides unique insights into the architecture, dynamics, and mechanisms of action of these essential biological components.
In this work, we investigate the magnetic properties of the Fe/GaAs superlattice for various thicknesses of the iron magnetic layer. The study was performed within the framework of the Heisenberg model. The excitation spectrum and the magnetization per spin were calculated using the retarded Green function method. We have highlighted that the excitation spectrum splits into two sub-bands of different characteristics, which we have attributed to surface and bulk magnons. Comparison between the calculations and the experimental measurements of magnetization per spin allowed us to obtain a very satisfactory estimation of the exchange integrals. The combined effects of surface anisotropy and dipolar interaction were also investigated through numerical analysis.
The Jagiellonian positron emission tomograph (J-PET) is a novel technology employed to detect multiple photons from positronium annihilation. It employs plastic scintillator strips optimized for the detection of photons in the sub-MeV energy range. The experimental setup consists of a positron-emitting source surrounded by chambers coated with porous materials to facilitate positronium formation. Owing to its large geometrical acceptance and high angular resolution, J-PET enables the reconstruction of various kinematic configurations of positronium annihilations, allowing for precise measurements of angular correlations in ortho-positronium decays. The detector has already demonstrated high sensitivity in charge–parity and charge–parity–time symmetry tests based on such correlations. In the present work, we report a systematic study of the effects of non-uniformity in porous materials used for positronium production in the J-PET setup, performed in the context of a charge–parity–time symmetry test. The systematic uncertainty obtained from this study is 0.59 x 10-5, and contributes negligibly to the total uncertainty of the charge–parity–time symmetry test.
Mn-based zero-dimensional metal halide perovskites have attracted much attention in the field of lead-free optical materials due to their rich manganese reserves, environmental friendliness, and the unique d–d transition characteristics of Mn2+. However, the poor water and oxygen stability and single luminous color of the intrinsic material severely limit the practical applications. In this paper, high-quality all-inorganic zero-dimensional perovskite Cs3MnCl5 single crystals were successfully prepared by the vacuum solid-state reaction method, and the regulation mechanism of heterovalent ions (Ag+, Ce3+, Sb3+) on the stability and luminescence properties of the materials was studied by B-site doping. X-ray diffraction and X-ray photoelectron spectroscopy analysis confirm that the doped ions successfully enter the Cs3MnCl5 lattice and occupy the Mn2+ sites, resulting in lattice expansion. Optical characterization shows that the intrinsic Cs3MnCl5 exhibits a bright green emission at 520 nm derived from the 4T1–6A1 transition of the Mn2+ tetrahedral coordination. Ag+ doping significantly improves the environmental stability of the material, and the maintenance time of green fluorescence in a high-humidity environment increases by more than ten times compared with the intrinsic material. Ce3+ doping induces the dual luminescence of violet (≈ 420 nm) derived from the Ce3+ 5d–4f transition and green emission from Mn2+, and the dual intensity ratio can be flexibly adjusted by excitation wavelength to achieve cold white light emission at 365 nm excitation. Sb3+ doping introduces orange emission (≈ 585 nm), derived from the Sb3+ 3P1–1S0 transition, resulting in yellow–green fluorescence. This work provides a new design idea for the application of Mn-based zero-dimensional halides.
We present a uniform analytical formulation for electromagnetic scattering by a circular aperture in an infinite perfectly electrically conducting plane. The formulation extends the boundary diffraction wave theory by incorporating both incident and reflected field contributions into a single analytical framework. A detour parameter combined with Fresnel uniformization is used to obtain a continuous edge-integral representation through the light–shadow transition. The resulting formulation reduces the aperture problem to a one-dimensional rim contribution and provides a compact analytical description of circular-aperture diffraction from a conducting screen over the considered angular range. Numerical evaluations based on the derived expressions illustrate the smooth behavior of the angular field, the symmetry associated with the conducting boundaries, and the edge-enhanced oscillatory features arising from the combined incident, reflected, and diffracted contributions. The main contribution of the study is a detour-enhanced uniform boundary diffraction wave formulation that provides a compact analytical representation of conductive circular-aperture diffraction and establishes a structured basis for future comparison with full-wave numerical and experimental benchmarks.
The paper presents selected results of the assessment of straightening processes of steel sheets and plates in terms of monitoring changes in mechanical residual stresses. For the stress investigation, a method based on magnetic Barkhausen noise measurements was applied, and the custom measuring set-up was used. The study examined two different technological processes of leveling, based on tension for thin metal sheets and three-point overbending of thicker plates. The results are presented graphically in the form of directional diagrams of Barkhausen noise, as well as vectors representing orthogonal principal stresses in the cross-section plane. In general, an unfavorable stress state was observed on the opposite sides of the investigated sheets in the initial condition. The applied straightening operations resulted in a significant redistribution of residual stresses, in terms of both magnitude and sign.
The most popular loss model for electrical steel sheets is the three-component model, which divides the specific total loss into hysteresis, classical eddy current, and excess components. The latter component is defined as the difference between the measured loss and the loss calculated using Maxwell's equations. The origin of the excess component has been a subject of debate for many years. Initially, it was associated with hysteresis loss and later with micro-eddy currents. Furthermore, the interdependence of the components complicates their modeling. This paper presents the results of research and analysis of loss components for the three-component model, taking into account the phenomenon of magnetic anisotropy. The studies were conducted on samples of conventional grain-oriented electrical steel sheet for several selected magnetization directions. The results indicate a correlation between the hysteresis and excess components for different magnetization directions. The paper proposes combining both components in a loss model for electrical sheets.
The paper concerns the construction of a system for automatic measurement of the magnetic field distribution on the surface of magnetic materials during their magnetization. Knowledge of this distribution allows one to assess whether a given element has major structural defects, such as cracks, holes, or foreign material inclusions. This is crucial information that determines the suitability of a given element.
The paper presents measurements and analysis of the magnetic properties of VITROVAC 6030 amorphous ribbons. Hysteresis loops were measured at a frequency of 1 kHz for standardized (sinusoidal) excitations and non-standard operating conditions, i.e., under harmonic flux density waveforms and in the presence of tensile stress. The effect of such operating conditions on the magnetic parameters was analysed.
This experimental study investigates welding operation on two magnetic shielding materials (80Ni-Fe and 50Ni-Fe), and the results indicate that, especially at lower excitation amplitude and frequency (50 Hz), the permeability of the welded joints can be significantly lower, i.e., reduced by up to 80% from the original value. At a higher frequency (400 Hz), the apparent degradation is not as severe, mostly because the apparent permeability is significantly lower due to global eddy currents. If welds constitute only a small proportion of the overall volume of the shield, the equivalent permeability is affected proportionally to the reluctance of each part. Recommended annealing is unable to fully recover the initial permeability measured at lower frequencies, but it is beneficial in improving the permeability.
