The dielectric properties and phase transition behavior of BiFeO3 (BFO) ferroelectric thin films are explored using Landau-Ginzburg-Devonshire theory, accounting for polarization variation near the surfaces. The Euler-Lagrange (E-L) equation is numerically solved to model switching properties under an applied step electric field. Dielectric hysteresis loops are generated for various thicknesses and temperatures, revealing a critical thickness of 0.452 nm, revealing a critical thickness of 0.452 nm, which highlights BFO's potential for nanoscale applications. The electric susceptibility is computed for several film thicknesses, showing a high value (similar to 10(4)) near the transition temperature, even for a film thickness of 1 nm. At room temperature, the susceptibility increases as the film thickness decreases, reaching a value of 51.7 at 30 degrees C for the 1 nm film. These findings are consistent with experimental observations that report an average dielectric constant of approximately epsilon similar to 50 in a single BFO crystal. Additionally, at room temperature, the calculated average polarization for BFO films with thicknesses between 1 nm and 6 nm falls in the range 0.50-0.55 C/m(2), indicating a relatively high value compared with other ferroelectric materials.
(Ca,V) co-doping effects on the structural, optical, and magnetic properties of zinc oxide nanoparticles (NPs) were explored. The nanoparticles were synthesized via a modified sol-gel route. X-ray diffraction analysis confirms the hexagonal polycrystalline wurtzite phase. No segregated secondary phases or Ca/V-rich clusters were detected. Morphological observations were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). EDS analysis revealed the existence of all elements in all the regions of the sample. TEM images show an almost prismatic cylindrical shape of the nanoparticles. Optical studies carried out by UV-Vis spectroscopy indicated a decrease in the value of the band gap after (Ca,V) incorporation. Magnetic measurements reveal a clear hysteresis showing the ferromagnetic behavior of this kind of material. These results are very promising for many technological applications such as hyperthermia, gas sensors, and optoelectronics.
Nickel oxide (NiO) and silica (SiO2) nanoparticles were incorporated into a carbon nanoporous matrix based on a pyrogallol-formaldehyde (PF) matrix via the sol-gel method. Various characterization techniques were performed to investigate the PF matrix, PF:NiO and PF/SiO2:NiO nanocomposites. XRD patterns revealed broad peaks characteristic of amorphous SiO2 and carbon phases characteristic of both amorphous SiO(2 )and carbon phases along with three characteristic nickel (Ni) peaks in the two nanocomposites PF:NiO and PF/SiO2:NiO. SEM images showed a significant number of particles covering the PF matrix surface in the PF/SiO2:NiO nanocomposite. The TEM images confirmed the porous structure of the PF matrix, a uniform dispersion of Ni nanoparticles in the PF:NiO nanocomposite and notable nanoparticle agglomeration in the PF/SiO2:NiO nanocomposite. Electrochemical measurements demonstrated that the sensitivity of the non-enzymatic glucose sensor increases with decreasing specific surface area. The electrical conductivity of the materials was found to depend on pore volume, decreasing as pore volume increased. The PF/SiO2:NiO nanocomposite exhibited promising performance as a non-enzymatic glucose sensor with a sensitivity of 585 & micro;A & centerdot;mM(-1)& centerdot;cm(-2 )and a low electrical conductivity of approximately 10(-8) Omega(-1)& centerdot;cm(-1).
The effect of cobalt doping with a concentration of 3 at. % on the structural and optical properties of ZnO oxide nanoparticles (NPs) prepared via a modified sol-gel method was investigated. X-ray diffraction analysis using Rietveld refinement confirms the hexagonal wurtzite ZnO phase nanostructure belonging to P63mc space group. No segregated secondary phases or Co-rich clusters were detected. In the second step, the obtained powders were deposited on a Suprasil glass substrate by the pulsed laser deposition technique. X-ray diffraction with Rietveld refinement confirms that the thin film exhibits an intense (002) XRD peak, indicating that it has a c-axis-preferred orientation. Raman studies confirm the crystalline nature of Co-doped ZnO thin films and nanoparticles. The combination of these two synthesis techniques demonstrates the potential of the protocol for the deposition of thin layers with adjusted properties.
In the present work, p-type organic field-effect transistors based on poly (3-hexylthiophene) (P3HT) enriched by gallium doped-zinc oxide (GZO) nanoparticlethin films as the active layerwere fabricated using the sol-gel technique coupled with spin-coating method and characterized using varioustechniques. The morphology of the thin films was analyzed using atomic force microscopy (AFM) and scanning electronmicroscopy (SEM) techniques, and their optical properties were investigated using the UV-Vis-IR spectroscopy technique. In order to investigate the effect of Ga doping concentrationon the electrical performances of the organic thin-film transistors (OTFTs) based on P3HT:GZO thin films, the current-voltage (I-V) measurements were carried outin the dark and in daylight using a Keithley 2612B Source Meter. The results demonstrate the ability to control both threshold voltage (V-th)and hysteresis by adjusting the Ga doping concentration within the active layer of the transistor devices. Moreover, the fabricated OTFT-P3HT:GZO devices exhibited significantly high performance, achieving a current ratio (I-on/I-off)of 3.5 & times; 10 & sup3; with 1% Ga loading and demonstrating a 100-fold enhancement in field-effect saturation mobility (mu(sat)) with 3% Ga loading, thereby showcasing their promising potential in a variety of practical applications, including cost-effective photodetectors and sensors
The goal of this study is to synthesize and characterize manganese-doped Dy2O3(Dy2O3/Mn) nanostructures for catalytic applications. To create materials with optimized morphological and structural properties, a low-cost hydrothermal route was used. Before being characterized, Dy2O3/Mn nanostructures were annealed at 500 degrees C. XRD measurements revealed that sample has a cubic phase structure, with a crystallite size of 37.7 nm. SEM and EDS techniques were used to examine the morphology and chemical composition, and the efficiency of the synthesis route was confirmed. Diffuse reflectance spectroscopy confirmed our samples' absorption in the visible region, and the band gap energy was found to be around 2.87 eV. Methylene blue (MB) dye was used to investigate the photocatalytic activity of Dy2O3/Mn nanostructures under visible light. Over six hours, a significant degradation efficiency was observed, with a degradation rate over 80%.
This study examines the crystallization of sputtered amorphous silicon (a-Si) thin films in contact with aluminum thin films on Corning glass substrates under continuous-wave (CW) laser irradiation. The study reveals key factors that affect the transition from amorphous to polysilicon by varying laser power densities and exposure durations. The crystallinity was assessed by Raman spectroscopy, while the surface morphology and structural alterations were examined using scanning electron microscopy (SEM). The results demonstrate that crystallization occurs beyond a certain threshold power density, with the creation of polysilicon being enhanced by increased laser intensity and longer exposure time. The results also show that the stacking order of silicon and aluminum layers directly affects crystallization behavior. This aspect has not been previously explored. These results improve understanding of laser-induced aluminum-mediated crystallization, which has implications for optoelectronic applications and thinfilm technologies.
A sample of calcium-doped zinc oxide (CZO) thin films of varying thicknesses were prepared by the pulsed laser deposition technique (PLD) on glass substrates. The film samples were grown at constant oxygen pressure. The pulsed laser deposition target used was Ca-doped zinc oxide 3 at. % nanopowder synthesised by a modified sol-gel process. The structural, morphological and optical properties of the CZO thin film were studied. From the X-ray diffraction analysis, the orientation of Ca-doped zinc oxide thin films was found to be along the c-axis, displaying only a (002) diffraction peak. The X-ray diffraction spectra revealed that the crystalline quality of the film was enhanced and grain size grew by increasing the film thickness. Cross-sectional microscopy images show the formation of columnar structure in the obtained thin film with low surface roughness when the film thickness increases. CZO thin film is highly transparent in the visible wavelength region with a transmittance higher than 90% for the lowest thickness. The calculated optical band gap is approximately 3.4 eV. The obtained results revealed that our samples are promising as transparent conducting oxide layers in many technological applications.
The elemental abundances of neon isotopes provide valuable insights into stellar evolution and nucleosynthesis. In this study, we calculate the abundances of the isotopes Ne-18, Ne-19, Ne-20, Ne-21, and Ne-22 across the five principal evolutionary phases of the Sun: hydrogen burning, lively old age, onset of rapid growth and red giant, helium-burning, and helium-exhaustion. The calculations were carried out using the open-source NucNet Tools package, developed by the Webnucleo Group at Clemson University. Initial isotope abundances were adopted from standard proto-solar compositions. Their evolution was computed under static hydrostatic burning conditions, assuming constant temperature and density within each phase. The results show that the stable isotopes Ne-20 and Ne-22 remain dominant throughout the Sun's lifetime, whereas the short-lived isotopes Ne-18 and Ne-19 decay rapidly during or shortly after the hydrogen-burning phase. The predictions obtained for the helium burning and exhaustion phases provide quantitative neon-isotope abundances that are not extensively reported in the existing literature. These results offer valuable reference values for future studies of solar and stellar evolution, nucleosynthetic pathways, and isotopic modeling.
Nanostructured Fe90Sb10 (wt.%) alloys were synthesized by mechanically alloying pure iron and antimony powders in a high-energy planetary ball mill. The milling duration was optimized to achieve a nanostructured mixture and form a supersaturated solid solution of alpha-Fe(Sb). Subsequently, thin films were fabricated through thermal evaporation (physical vapor deposition) under a vacuum of 2.1 & times; 10(-5) mbar, utilizing an electrically heated tungsten boat and the supersaturated solid solution alpha-Fe(Sb) powder obtained via mechanical alloying. The films were deposited on glass substrates. This study investigates the influence of milling time and film thickness on the structural and magnetic properties of Fe(90)Sb(10 )powders and thin films. Structural and magnetic characterizations were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The Fe(Sb) solid solution phase was identified after 12 hours of milling, with a particle size of approximately 18.16 nm with microstrain increasing to 0.19% after 36 hours. SEM analysis revealed a more homogeneous particle distribution as milling time increased. Furthermore, as the film thickness increased from 16 nm to 90 nm, a steady decrease was observed in the lattice parameter, accompanied by an increase in the average crystallite size from 5.9 nm to 16.8 nm and a slight increase in microstrain. In parallel, the coercive field dropped from 6.64 Oe to 3.05 Oe, suggesting improved magnetic softness in thicker films.
Abstract: Graphite nuclear properties, such as moderating power and absorption cross-section, are not as good as those of heavy water. However, graphite can be prepared in a pure form. Its structural and thermal properties are good, and it has a high thermal conductivity. The thermal neutron in graphite performs an average of 1200 scattering collisions before it is absorbed. This very low absorption cross-section makes graphite an ideal material for applications in nuclear reactors. In the current research, graphite is assumed as a diffusive medium due to its low absorption cross-section (0.0035 barn) and its atomic mass being close to that of the neutron. In this medium, the neutron absorbers boron (10B), cadmium (113Cd), samarium (149Sm), europium (151Eu), hafnium (177Hf), and gadolinium (157Gd) are considered individually. The aim of this paper is to obtain the solitary waveform of the reaction rate in a graphite diffusive medium using these neutron absorbers. This work shows that hafnium has the longest transition time among the materials examined in this research. This means that, for a constant transition length, hafnium requires more time to reach a steady state. The efficiency of hafnium as a neutron absorber is determined not only by the magnitude of its thermal neutron absorption cross-section, but also by its exceptional capacity to absorb higher-energy neutrons over the energy range of their deceleration.
In this paper, we present cross-section calculations for negative ion formation (ion-pair formation) in hydrogen-hydrogen atom collisions based on the classical trajectory and quasi-classical trajectory Monte Carlo models. By comparing our results with available experimental data and theoretical predictions, we find that the QCTMC calculations align well with previous studies. However, the negative ion formation cross-sections obtained using the CTMC model underestimate all previously reported theoretical and experimental values. Nonetheless, the CTMC results show good agreement with the Q-, P-series approximation in the energy range of 1–10 keV. We present negative ion formation cross-sections for impact energies ranging from 1 keV to 100 keV, which are relevant to applications in astronomy, atmospheric sciences, plasma laboratories, and fusion research.
Proton radiography (PR) is a new imaging method that allows direct measurement of the proton energy dissipation in different tissues. Proton radiography enables fast and effective high-precision lateral alignment of the proton beam and target volume in human irradiation experiments with limited dose exposure. The benefits of PR can be summarized as: 1) high image resolution, 2) the complete field of view can be measured with one short proton spill, 3) short data acquisition time, and 4) simple data processing. Enhancing image contrast can be achieved by substituting cuts on the scattering angle with the use of a magnetic lens (ML) system, resulting in optimal images of objects. The current study is primarily focusing on proton acceleration via target normal sheath acceleration (TNSA) using nanowire-coated foils as targets, followed by an investigation of the LET, range, and dose of protons. In this work, simplified physical models of proton transport, including Bethe-Bloch energy loss, energy straggling, and multiple Coulomb scattering (MCS), are used in the 0-300 MeV energy range of interest to analytically quantify the tradeoffs and scaling relationships between dose, spatial resolution, density resolution, and voxel size. We found that dose (D) is directly influenced by the size of voxel alpha and the necessary density resolution delta, which highlights a very strong dependence on voxel size. Our work shows that the average dose increases with increasing number of protons, while the average dose decreases with increasing proton beam energy, which is in good agreement with the other references. These studies demonstrate that the dose D of water, breast, brain, lung, and eye tissues is directly influenced by the size of voxel alpha and the necessary density resolution delta, adhering to the relationship D (SIC)alpha(-5)delta(-2), which highlights a very strong dependence on voxel size.
This paper underlines the need to improve SRR cell design parameters to achieve both a negative refractive index and optimal impedance matching for advanced metamaterial applications. Metamaterials have unique light manipulation characteristics because of their negative refractive index and excellent impedance matching. This paper looks at numerous split-ring resonator (SRR) cell designs to find the best combinations. Square SRR cells consistently achieved a negative refractive index and excellent impedance matching throughout simulations, outperforming alternative forms such as circular SRRs. Increasing strip width often improves the negative refractive index, although it may create dispersion. Optimal separation distance resulted in a negative refractive index and perfect impedance for particular SRR forms (SSRR, HSRR, and OSRR); however, CSRR designs degraded with greater separations. All SRR forms produced satisfactory results, however CSRR designs had a somewhat poorer performance. Notably, a greater outer side (a = 22mm) SSSR cells resulted in a much higher negative refractive index throughout varying strip widths and separation distances.
This article introduces a modified version of the Lorentz transformation equations that transform spacetime coordinates between two inertial frames when the relative motion between them occurs along the X-, Y-, and Z-directions, and represents an extension of the one-dimensional Lorentz transformation equations to three spatial dimensions. Making use of the invariance of the spacetime interval, the paper demonstrates that an event in the spacetime continuum can be represented by six coordinates, of which the first three represent the spatial coordinates, and the remaining three represent the time coordinates. By employing the notion of a position six-vector, the correct matrix form of the Lorentz transformation equations of order 6 x 6 has been thoroughly developed. In addition, the D'Alembert operator, the basic ingredient of the wave equation, is shown to be form-invariant under the modified Lorentz transformation equations. Furthermore, the relativistic velocity addition formulas, as well as the Lorentz transformations of linear momentum and energy, have been theoretically analyzed on the basis of the extended Lorentz transformations. Finally, the particular purpose of this work is to present equal and opposite relativistic spacetime coordinate transformation equations between inertial frames, which properly allow for the formulation of the correct matrix form of the Lorentz transformation equations in terms of the position six-vector.
Copper silica (CuSi) plasma was generated under atmospheric pressure using argon gas by immersing a piece of (Si) metal in the prepared nano-Cu liquid for periods of 6 and 8 min. Then, a spectroscopic diagnosis of the generated plasma was performed at a constant applied voltage of 11 kV and a frequency of 50 kHz under direct-current conditions, with the argon flow rate varied between 0.5 and 2 L/min. Changing the duration of immersion within the nano-Cu liquid and the flow rate of argon affected the intensity of the resulting spectral peaks. The generated plasma had the following parameters: Te values of 3.732-4.981 eV and 1.220-1.396 eV, and ne values of 2.700 x 10(18 )- 3.588 x 10(18) cm(3) and 1.290 x 10(18)-2.074 x 10(18) cm(3) for the two times used. When CuSi nanoparticles (NPs) were synthesized under the same laboratory conditions, with the argon flow rate fixed at 2 L/min, the energy gap was 3.74 eV, prepared by Si for 6 min in Cu-liquid for 6 min, and 3.62 eV, prepared of Si for 6 min in Cu-liquid for 8 min. The results showed that the Cu-liquid increased the electrical conductivity in the CuSi cold jet plasma system, which affected the values of the plasma parameters and the synthesis of CuSi NPs as a result of increased energy gain, which accelerated and increased the electron process and ultimately increased the ionisation process.
This study assessed the radioactivity levels in soil samples from Anambra and Imo States, two regions affected by the Nigerian Civil War. Using a thallium-activated sodium iodide detector, a total of 80 stratified, randomly collected soil samples were analyzed. The detected radionuclides included non-serial K-40 and decay series of U-238 and Th-232, as well as trace levels of the anthropogenic Cs-137. Their spatial variability and associated health implications were also evaluated. The average activity concentrations in Anambra State were 835.91 f 7.40 Bq kg(-1) for 40K, 21.05 f 3.65 Bq kg(-1) for 238U, 12.99 f 0.85 Bq kg(-1) for 232Th, and 3.88 f 0.10 Bq kg(-1) for 137Cs. In Imo State, the respective values were 761.29 f 6.63, 19.19 f 2.97, 9.29 f 1.52, and 5.39 f 0.25 Bq kg(-1). The estimated mean absorbed dose rates were 52.65 nGyh(-1) for Anambra and 46.38 nGyh-1 for Imo, corresponding to annual effective dose equivalents of 0.06 mSvy-1 for both states, a value well below the global safety thresholds. Spatial analysis revealed that 40K levels were influenced by potassium-rich soils and intensive agricultural practices, while geological formations governed the distribution of 238U and 232Th. This study confirms that current soil usage poses no immediate radiological risks. However, proactive monitoring is recommended to mitigate potential long-term radiological impacts.
The Hamiltonian of an exciton in a thin layer of WS2-transition metal dichalcogenide (TMD) was solved by the 1/N expansion method, and the corresponding exciton bound-state energies were obtained. The Hamiltonian describes an electron-hole particle system interacting through an attractive Rytova-Keldysh potential (8 & Euml;& Auml;) in a sheet of WS2, which is presented in an external uniform magnetic field applied perpendicular to the material sheet plane. We used the computed eigenenergies to calculate the partition function, which depends on the temperature and magnetic field. We calculated the magnetic and thermal quantities of WS2 TMD material sheet for various values of magnetic field strength and temperature range. The comparisons show that the calculated exciton energy spectra against experimental and theoretical corresponding results are in very good agreement. We have displayed the dependence of magnetization, susceptibility, entropy, and heat capacity as a function of magnetic field and temperature. The paramagnetic behavior of materials over a wide range of magnetic fields was considered. In addition, the density of states (DOS) of TMD-WS2 material was calculated, and the resulting DOS plot shows an oscillator peak behavior for various ranges of the magnetic field strengths.
Proton therapy is one of the most promising treatments for several types of tumors, such as those of the eye, brain, and breast, as it benefits from a sharp Bragg peak as well as a spread-out Bragg peak (SOBP) in the tumor region. The Bragg peak helps to deliver the maximum dose to the tumor and the minimum dose to the sensitive organs near the tumor. It has been shown that the addition of nanoparticles to the tumor can improve the treatment gain in radiation therapy. In this study, the microscopic dose enhancement ratio as well as the DNA damage frequency caused by 62.8 MeV protons with the presence of 3000 ppm (i.e., 30 mg/g) Au, Pt, C, B-11, and Fe3O4 nanoparticles were investigated using the Geant4-DNA Monte Carlo toolkit. In addition, the cell survival curves were obtained and compared for the condition with and without nanoparticles. All simulations were performed at different locations along the proton range: at the beginning, in the middle, and at the end of the SOBP. The highest dose enhancement in the fibroblast cell was observed for Pt nanoparticles (up to 4%), followed by Au nanoparticles (up to 2.4%), while the lowest dose enhancement was observed for C nanoparticles (up to 0.32%). At the end of the proton range, higher levels of DNA damage were observed than at the beginning of the path and at the center of the SOBP. Unlike some previous studies, this work simulated more realistic clinical conditions, and the obtained results are in good agreement with some experimental results reported in the literature. In conclusion, the combination of Au and Pt nanoparticles with proton therapy has a superiority over C,B- 11, and Fe3O4 nanoparticles.
The photothermal conversion characteristics of black, composite, and selective coatings were investigated. ZrO2 and Fe particles were incorporated into the heat-resistant black paint (HRP) to improve the conversion capability of the coating. The coatings and the particles were applied onto aluminium substrates using the direct spraying method. This resulted in layers having thicknesses of 323.5 mu m and 837 mu m for the ZrO2 -and Fe-containing coatings. The addition of these powders led to a decrease in the coating density from 1.67 g/cm(3) to 0.31 g/cm(3) and 0.5 g/cm(3) for the ZrO2 /HRP and Fe/HRP coatings, respectively. The addition of the particles was found to improve the solar-to-thermal conversion of the primary paint significantly. Maximum absorbance of 97.81% and a substrate temperature of 382.65 K after 40 minutes of radiation exposure were achieved using the Fe/HRP system. The photothermal conversion characteristics were analyzed based on the structural, compositional, and physical properties of the composite coatings. The absorption spectra in the UV-Vis range of the Fe/HRP coating showed higher peaks than those exhibited by the ZrO2 /HRP coating, emphasizing the higher photo-thermal conversion of the Fe/HRP coating. Owing to their ease of application and high conversion performance, the developed coatings are superior to many existing coating systems for flat-plate collectors.
