This investigation presents a comprehensive electrical performance comparison between two high electron mobility transistor (HEMT) architectures: GaN/Al0.32Ga0.68N/GaN (structure A) and GaN/In0.17Al0.83N/GaN (structure B), utilizing Silvaco ATLAS device simulation software to incorporate both spontaneous and piezoelectric polarization effects through the self-consistent solution of the one-dimensional Poisson and Schrödinger equations. Analysis of current-voltage characteristics and transconductance measurements revealed that the GaN/In0.17Al0.83N/GaN HEMT demonstrates significantly superior electrical performance compared to its GaN/Al0.32Ga0.68N/GaN counterpart. Under operating conditions of zero gate bias and 12 V drain-source voltage, the maximum drain current reached approximately 0.19 mA for (structure A), while (structure B) achieved substantially higher performance with 130 mA. Transconductance analysis further supported these findings, showing peak values of 27.5 mS for the GaN/In0.17Al0.83N/GaN configuration versus 0.075 mS for the GaN/Al0.32Ga0.68N/GaN structure at gate-source voltage of –2.5 V and drain-source voltage of 5 V. Compared to Structure A, the optimized Structure B device achieves a 700-fold current increase and a 360-fold transconductance enhancement. The improved carrier density and modulation efficiency establish this structure as a robust candidate for high-power, high-frequency operations. The enhanced performance of (structure B) stems from its ability to generate higher sheet carrier densities through spontaneous polarization effects, making it a more effective solution for high-performance transistor applications compared to the conventional (structure A) design.
An experimental setup has been developed for the in situ optical diagnostics of the formation of submicron particles using the micronization method of rapid expansion of supercritical solutions (RESS). The particle sizes are controlled based on measurements of the Mie scattering indicatrix (in the angle range of 15°–160°) of probing laser radiation (λ = 450 nm). The paper describes a technique for modeling the scattering indicatrix of an ensemble of particles based on the solution of the Mie problem. Ibuprofen particles with sizes of 400–2000 nm were obtained and characterized at supercritical initial conditions of 130 bar and 310 K. A method is proposed to increase the efficiency of ibuprofen micronization in the RESS process based on explosive boiling of a subcritical CO2 + ibuprofen mixture at process parameters of 70 bar and 302 K. The predominance of submicron ibuprofen particles with a lognormal distribution and an average size of 540 ± 140 nm is shown.
Structural, electronic and magnetic properties of (TiXSb: X = Ir, Rh) half-Heusler and their Ti2RhIrSb2 double half-Heusler alloys have been explored, by utilizing ab-initio principles via the density functional theory, the generalized gradient Wu–Cohn approach and the full potential linearized augmented plane wave method. The gotten results from the electronic and magnetic computations reveal that the present compounds TiIrSb, TiRhSb and Ti2RhIrSb2 exhibit a non-magnetic semiconducting behavior; this is dominantly due to the strong hybridization between the d–d atomic orbitals. From the ground state results, we have found that these compounds are thermodynamically stable and could be synthetized experimentally. These outputs serve as a promising basic data for novel future research particularly for spintronic requests.
This study focuses on the synthesis of CuAl2O4 nanostructures by the sol-gel method under atmospheric air. The obtained sample underwent several experimental analysis and characterizations. The X-ray diffraction confirms the development of a pure spinel CuAl2O4 structure, with an average crystallite size of 24 nm. The microstrain shows that CuAl2O4 is subjected to compressive stress (ε < 0), with a slight deformation of the lattice. Furthermore, the fourier transform infrared spectroscopy confirmed the presence of Cu–O and Al–O bonds. Scanning electron microscopy (SEM) analysis showed irregular nanocubes randomly dispersed with sizes ranging from 0.14 to 0.30 µm. The diffuse reflectance revealed an energy gap of 1.98 eV, with a light absorption capacity in the visible region. Electrochemical measurements in Na2SO4 allowed the estimation of the flat band potential of CuAl2O4 (+0.23 V vs. SCE), Saturated Calomel Electrode (VCE). The photocatalytic activity of the spinel is tested on the degradation of tartrazine (E102) under visible light. A high efficiency in the removal of 95
Nanomaterial-assisted interfacial engineering offers a practical route to improve crystalline-silicon photovoltaic performance by facilitating charge extraction and suppressing recombination losses. In this work, a hybrid silicon/carbon-nanotube/zinc-oxide solar-cell architecture was developed in which a single-walled carbon-nanotube network serves as a conductive percolation scaffold for carrier collection, while a sol–gel-derived zinc-oxide layer serves as an electron-selective transport layer. The carbon-nanotube coating was chemically treated to improve dispersion and adhesion, the zinc-oxide layer was deposited by spin coating, and post-deposition annealing between 100 and 175°C was used to tune crystallinity and microstructure. Structural and morphological evolution was assessed by X-ray diffraction, scanning electron microscopy, and atomic force microscopy, and photovoltaic behavior was evaluated by current-voltage measurements under simulated solar illumination of 100 mW cm–2. Compared with the reference device, the optimized hybrid cell reached a power-conversion efficiency of 20.4
This study reinvestigates the potential of 2-amino-5-nitropyridinium cadmium chloride as a candidate material for nonlinear optical applications. The crystal and its molecular structure were reinvestigated using single crystal X-ray diffraction. The Ultraviolet spectroscopy were recorded, and the compositional ratio of the sample was examined through energy-dispersive X-ray analysis. A comprehensive analysis of the compound’s thermal stability was also conducted. Results show that the crystal belongs to the monoclinic system with a centrosymmetric group C2/C. Employing the Kurtz and Perry technique, the nonlinear optical behavior of the compound was found to slightly surpass that of potassium dihydrogen phosphate by a factor of 0.98. This enhancement in nonlinear optical response positions the compound as an intriguing candidate as a frequency-doubling material.
This study reports the experimental determination of the solubility of three types of ion-exchange resins—Dowex sulfonic cation exchange resin, NWR AQUA mixed-type macroporous resin, and Waterlux B30 anion exchange resin—in supercritical carbon dioxide with acetone additives (0, 5, 10, and 15 wt
The reaction between glycine and ninhydrin, a classical colorimetric analyze for amino acids, peptides, and proteins, was investigated through detailed kinetic and thermodynamic analyses to elucidate its mechanistic features and optimize experimental conditions. The study demonstrates that the reaction predominantly follows pseudo-first-order kinetics when either glycine or ninhydrin is present in excess, with the reaction rate largely dependent on the concentration of the limiting reagent. Thermodynamic parameters reveal a moderate activation enthalpy (ΔH* = 65.06 kJ/mol) and activation energy (Ea = 67.57 kJ/mol), while the negative entropy of activation (ΔS* = –69.61 J/mol K) indicates the formation of a structured transition state, consistent with an association type rate determining step. Kinetic measurements across different pH values show that the reaction is highly pH-dependent, exhibiting minimal activity under strongly acidic conditions and maximal rates in the near neutral to mildly alkaline range (pH 6–8). At higher pH (pH 10), the reaction displays sigmoidal kinetics, suggesting altered mechanistic pathways due to extensive deprotonation and potential instability of intermediates. These findings provide comprehensive insights into the glycine ninhydrin system, offering guidance for precise control of experimental parameters, enhanced reproducibility, and improved analytical applications in amino acid and protein quantification.
This research article wants to explore the electronic-structure traits of transition metals of titanium (Ti) and chromium (Cr) doped-zinc oxide (ZnO) heterocluster through H2O molecule adsorption using first-principles studies. A detailed study was performed using “DFT” calculations at the “CAM-B3LYP-D3/6-311+G(d,p)” level to investigate how H2O is captured by a ZnO, Zn(Ti)O or Zn(Cr)O heterocluster. The weak signal strength observed near the parallel edge of the nanocluster sample could be because of the non-spherical arrangement of the ZnO, Zn(Ti)O or Zn(Cr)O heterocluster caused by H/OH binding. This hypothesis about energy absorption was supported by analyzing the density distributions of “TDOS, PDOS, OPDOS, LOL” for both the bare and water-coated ZnO, Zn(Ti)O and Zn(Cr)O heteroclusters. An isosurface map showed a larger area involved in H2O adsorption on the ZnO, Zn(Ti)O or Zn(Cr)O surface, leading to the formation of a hydrated ZnO–H2O, Zn(Ti)O-H2O and Zn(Cr)O- H2O complexes, with specific atoms labeled as “O1, Zn15/Ti15/Cr15, O27, H29, and H30.” Based on this, it could be said that the Zn/Ti/Cr in the cubic ZnO, Zn(Ti)O or Zn(Cr)O, respectively has a greater ability to accept electrons during H2O adsorption. It’s also important to note that when all the surface elements of ZnO, Zn(Ti)O or Zn(Cr)O are covered by “OH–/ H+” ions, the semiconducting treatment is restored. These findings suggest that the electronic properties can be adjusted by controlling the adsorption position on the ZnO, Zn(Ti)O or Zn(Cr)O surface. This study aims to explore methods for treating water and enhancing the effectiveness of titanium zinc oxide and chromium zinc oxide alloy photocatalysts in removing pollutants. The findings can potentially lead to the development of more efficient water purification processes through further research on photocatalysts.
Information on the location of ancient production sites plays a crucial role in reconstructing the historical and cultural landscape and in analyzing past settlement patterns. Pottery is one of the main types of production, but our knowledge of the past is limited by the availability of sources. Regarding the development of production in northwestern Colchis, we have no written sources and can rely only on archaeological data. However, despite nearly a century and a half of archaeological research, which has provided compelling evidence of extensive pottery production in this area, we have very little understanding of the production centers themselves, which, like any other production, are tied to corresponding mineral sources. This study aims to determine the resource base, identify existing trends, and create predictive models for the location of production centers through the study of natural clays and finished ceramic products, using a combination of modern physicochemical and technological methods. This paper analyzes the results of studies of 23 clay samples and 63 plinth samples. The set of research methods was determined by both the available material and the objectives of the study. Technological traditions of ceramic production were studied using A.A. Bobrinsky’s method. The production sites were determined based on the elemental and mineral composition of clays and ceramic products obtained while using X-ray fluorescence (XRF), X-ray diffraction (XRD), and Mössbauer spectroscopy. A combination of these methods provides the most comprehensive information on the composition of natural materials. Spatial analysis was performed using a GIS. The study revealed differences in the technological traditions of plinth production in the western and eastern parts of the Colchis region. It has been established that the iron content in clays and plinths is the marker of the place of production and is associated with the rivers originating in the slopes of the Greater Caucasus Range. The availability of comprehensive studies of the elemental and phase composition of materials allows for the collection of objective information on the production relationship between annealedproducts and natural raw materials.
We present a study on the equilibrium atomic volume and thermodynamic properties of α-U using first-principles calculations, along with harmonic and quasi-harmonic approximations. Our spin-polarized calculation of the equilibrium atomic volume of α-U shows good agreement with experimental results. However, there are discrepancies in the isochoric heat capacity of α-U obtained through the harmonic approximation, which agrees with experimental measurements below 150 K but deviates significantly above this temperature. On the other hand, the quasi-harmonic approximation yields result consistent with experimental measurements below 150 K, but shows substantial discrepancies above this temperature. We have also taken into account the calculated thermal expansion coefficient of α-U and have identified the absence of higher-order force constants as a significant factor contributing to the discrepancies between the calculated and experimental values of both isochoric and isobaric heat capacities above 150 K. This should be taken into consideration in future calculations.
In this work, nanocomposite films based on a polyethylene oxide : methylcellulose (50 : 50) blend were synthesized and reinforced with graphene nanoplatelets at varying concentrations (0–20 wt
In order to explain the life evolution mechanisms at the Earth and understand adaptive mechanisms developed by living organisms for survival, in this study we consider the influence of various external physical factors on the viability of living systems, and changes in the structure and composition of these systems in order to increase the likelihood of survival. To do this, we consider the physical, chemical, and biological processes that occur in living systems at both the molecular and cellular levels. This article is the second part of the review, where we discuss the impact of various types of energy exposure on living organisms and their possible evolutionary paths. This article discusses the mechanisms by which UV and VUV photons, high-energy ultrasound, and microwave radiation affect various biomolecules, such as DNA, proteins, and their constituent amino acids and nucleotides. It also examines the destructive effects of ultrasound on living cells and organs in humans and animals at various frequencies and powers.
This paper systematically investigates the synergistic etching behavior and mechanism of diamond particles using a binary Fe–CuO system at 900°C. XRD analysis indicated that a solid-state reaction occurred between Fe and CuO, generating FeO, Cu, and trace amounts of CuFe2O4, with FeO and Fe constituting the active etching medium. SEM observations revealed a distinct crystallographic dependence of the etching effects: the 100 surfaces exhibited regularly arranged square or rectangular etch pits with boundaries aligned along crystallographic directions, showing highly uniform morphologies; while the 111 surfaces displayed numerous ring-shaped etch pits, whose size and density varied significantly with the CuO content. The study demonstrated that CuO content played a key role in modulating the etching behavior: an appropriate addition significantly enhanced etching, particularly on the 111 surfaces and grain boundaries, whereas excessive addition led to weakened etching. Mechanistically, the exothermic Fe–CuO reaction provided localized high temperatures and highly active interfaces; the Fe–FeO synergy established a dynamic redox cycle enabling sustained etching; and CuO facilitated the initial reaction stage through auxiliary reduction and nano-effects.
The global push for sustainable energy has intensified the need for efficient, reliable energy storage, exposing the limitations of lithium-ion batteries (LIBs) due to lithium scarcity and cost. Sodium-ion batteries (SIBs) have emerged as a promising, cost-effective alternative for large-scale stationary storage, especially to support intermittent renewable sources. SIBs rely on reversible sodium-ion intercalation between anodes and cathodes, with electrolytes critically influencing ion transport, electrochemical stability, and overall performance. Electrolytes can be liquid, quasi-solid, solid, or hybrid, each balancing ionic conductivity, mechanical strength, and safety. Key factors include ionic conductivity, cation transference number, electrochemical stability, interfacial resistance, and formation of stable solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) layers, which govern charge/discharge kinetics, cycle life, and power density. Liquid electrolytes, often carbonate- or ether-based, remain dominant due to high ionic mobility and compatibility, while emerging hybrid systems aim to combine liquid-like conductivity with solid-state stability, suppressing dendrites and enhancing safety. Optimizing electrolyte properties is central to advancing scalable, high-performance SIBs.
Based on the investigation of spectral-brightness characteristics of chemiluminescence arising from the interaction in the Ru(bpy)3Cl2·6H2O-aluminum alkyl-oxygen system (bpy is 2,2'-bipyridyl), a new quantitative method for determining ruthenium in organic solvents is proposed. Triethylaluminum, triisobutylaluminum, and diisobutylaluminum hydride are taken as aluminum alkyls. The emitter of red glow is the triplet-excited cation Ru( bpy)_3^2 + * in the Ru(bpy)3Cl2 complex with aluminum alkyl. Linear dependences of the chemiluminescence intensity on the concentration of aluminum alkyl and ruthenium (in the range of [Ru] = 10–7 to 5 × 10–5 mol/L) were established. The obtained linear dependences can be used as calibration for the quantitative determination of ruthenium. Verification measurements of the ruthenium concentration in standard aqueous solutions with the subsequent transfer of ruthenium into the organic phase were carried out, which confirms the practical applicability of the method for the analysis of ruthenium compounds in aqueous media.
We conducted Stopping and Range of Ions in Matter (SRIM) Monte Carlo simulations to investigate how 1.25 MeV cobalt (Co) ions implant into different SnO2-based thin-film structures on silicon (Si) substrates. Three basic configurations were modeled that consisted of pure Si, a bilayer SnO2/Si structure, and a Pt-doped SnO2:Pt/Si heterostructure. Each model was developed according to the unique layer thicknesses, atomic compositions, and densities that were established from experimental and literature sources. The average depth of Co ion scattering during bombardment at 1.25 MeV achieved a projected range of approximately 4667 Å, which correlated with a straggle of 1666 Å. The Co ion distribution was slightly skewed, with a skewness of approximately –0.71, indicating non-uniform scattering that had occurred due to a combination of the two oxides and Si interfaces. Inclusion of platinum into the SnO2 layer generally modified the bonding environment, increased the stability of this lattice structure, and altered the disposition of the Co ions as well. The Si substrate, in contrast, influenced both backscattering and recoil behavior which lead to significantly different defect development and energy loss characteristics for the three sample configurations. These outcomes offer evidence that the SnO2:Pt/Si heterostructure has tunable defect engineering capabilities, where platinum doping in combination with the silicon heterostructure interface allows for stable structures with controlled vacancy charge concentrations. These properties are especially important for gas sensor applications, in which dopant active sites and surface vacancy play an important role in improving sensing selectivity and sensitivity.
Anodic aluminum oxide has been successfully prepared using different acid concentrations in the electrolyte, anodization voltages, and current densities. F+ spin centers were detected in all samples. The photoluminescence (PL) band at λ1 = 465 nm represents PL from F+. The PL band at λ2 = 635 nm is due to radiative recombination of photoexcited electrons in nonparamagnetic centers. The obtained samples are promising for the creation of optical sensors for biomarkers.
This work investigates the broadband dielectric response of solution-cast poly (ethylene oxide)/methyl cellulose blend films reinforced with graphene oxide (0–20 wt
The characteristics of charged particles generated by an electric current pulse passing through an aqueous sodium bicarbonate solution were studied. Polyethylene terephthalate film, DVD discs, or Kodak black-and-white photographic film with a sensitivity of 100 units were used as particle detectors. Dotted traces of complex shapes and traces of varying intensity but absolutely identical in shape were detected on solid-state detectors. When a particle impacted the photographic film, a loop-shaped trace of metallic silver 0.343 mm wide and 3.22 cm long was formed on it, rounded at the location of a permanent neodymium magnet. A model of the structure of an energetic charged particle is proposed, which is considered as an electric capacitor in the form of a multiply charged water cluster. It was found that the electric field energy of such a cluster can exceed 10–3 J. Based on this, the charge, size, and mass of the cluster were calculated. Analysis of a section of the cluster’s trajectory in a 2 T magnetic field allowed us to calculate the cluster’s velocity along the film surface (6.2 cm/s). It was shown that ions produced during cluster disintegration can be accelerated in the cluster’s electric field to an energy of 3.56 × 105 eV.
