Potassium-calcium-ammonium nitrate samples were obtained by varying the amounts of dolomite mineral (DM) and potassium chloride (KCl) from 0.5 to 25 g per 100 g of ammonium nitrate (AN) melt. The carbonate-chloride-nitrate melt was granulated by the prilling method. At 170 °C, the nitrate melt activated the dolomite mineral, converting CaO and MgO into plant-available forms. The simultaneous addition of DM and KCl significantly improved the mechanical strength of the fertilizer granules while reducing caking, porosity, and diesel fuel absorbency by a factor of 2–3 compared with AN granules containing magnesite. The optimal composition (AN:DM:KCl=100:12:12) was characterized by EDS, SEM, and DTA analyses, which confirmed its favorable structural and physicochemical properties. These findings demonstrate the potential of NKCaMg as a mechanically stable and agronomically effective fertilizer formulation.
Single crystals of the organic–inorganic hybrid bis((pyridin-1-ium-3-yl)methanaminium) hexachlorostannate(IV) dichloride, ([3-PyCH2NH3]2[SnCl6]Cl2), were grown and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes as a centrosymmetric structure comprising discrete octahedral [SnCl6]2– anions linked to protonated organic cations through charge-assisted N–H···Cl hydrogen bonds, forming a stable supramolecular framework. Bond valence sum calculations confirm the + 4 oxidation state of tin, supporting the structural model. Diffuse reflectance spectroscopy reveals a wide optical bandgap of 4.28 eV, indicating insulating behavior typical of chloride-based hybrids. Photoluminescence measurements show near-ultraviolet emission at room temperature, attributed to ligand-centered electronic transitions within the organic component. Third-order non-linear optical measurements demonstrate a measurable χ(3) value on the order of 10–11 esu, suggesting significant electronic polarization despite the centrosymmetric lattice. Dielectric analysis indicates strong frequency and temperature-dependent behavior, with higher dielectric constants at low frequencies due to interfacial and space-charge polarization, followed by stabilization at higher frequencies. AC conductivity studies suggest a transition from polarization-dominated transport to thermally activated hopping conduction. Hirshfeld surface analysis confirms that N–H···Cl hydrogen bonding dominates crystal packing. These results demonstrate the key role of hydrogen-bond-driven organization in determining the optical and dielectric properties of this hybrid material.
NiO/CuO/Co3O4 ternary nanocomposites (TNCs) were synergistically designed via hydrothermal method to enhance interfacial charge transfer and redox activity for high-efficiency supercapacitor applications. The structural analysis using XRD confirmed the coexistence of cubic NiO, monoclinic CuO and spinal Co3O4 phases with an average crystallite size of 21 nm, indicating the formation of a well-defined ternary system. XPS analysis verified the presence of Ni2+/ Ni3+, Cu2+ and Co2+/Co3+ oxidation states along with oxygen vacancies. FESEM and HRTEM studies revealed a hexagonal plate-like morphology with well-defined lattice fringes and polycrystalline nature of the prepared material. BET analysis showed a high specific surface area of 131 m2g− 1 with mesoporous structure ( 1.93 nm pore size), facilitating efficient electrolyte access and charge transport. Electrochemical measurements demonstrated excellent pseudocapacitive behaviour with a high specific capacitance of 1523 F g− 1 at 10 mV s− 1 scan rate and 1160 F g− 1 at 2 A g− 1 current density from CV and GCD curves, respectively. The electrode exhibited superior cyclic stability with 97.8
An organic single crystal of 2-aminobenzylaminium picrate (ABAP) was grown by the slow-evaporation solution method and structurally characterized to investigate proton-transfer-driven supramolecular organization and its influence on optical properties. Single-crystal X-ray diffraction confirms the formation of a charge-assisted hydrogen-bonded ionic framework composed of protonated 2-aminobenzylaminium cations and picrate anions. The crystal packing is stabilized by cyclic N–H•••O hydrogen-bond motifs and π•••π stacking interactions that promote cooperative donor–acceptor coupling within the lattice. Vibrational analysis shows good agreement between experimental and calculated spectra, supporting the optimized molecular geometry. UV–diffuse reflectance spectroscopy reveals an optical band gap of 2.80 eV, indicating semiconducting behaviour, while TD-DFT calculations confirm intramolecular charge-transfer transitions. Frontier molecular orbital analysis gives a HOMO–LUMO gap of 3.756 eV and demonstrates spatial separation of donor and acceptor regions. The results establish a clear correlation between proton-transfer-induced polarization, supramolecular organization and optical response, highlighting ABAP as a useful model system for structure–property relationship studies in hydrogen-bonded organic optoelectronic materials.
Numerical integration of definite integrals is important in fundamental and applied sciences. The error of approximate integral calculations depends on the initial data and specific requirements, which leads to the imposition of various conditions on the obtained calculations. In this paper, we consider the problem of constructing an optimal quadrature formula for the approximate calculation of Fourier integrals using the φ -function method. The error of the quadrature formula is estimated from above using the integral of the square of the function φ from the Hilbert space. Next, a function φ is chosen for which the integral of the square of the function on this interval takes the smallest value. The coefficients of the optimal quadrature formula are calculated using the obtained φ function. The optimal quadrature formula is exact for the functions e^σ x and e^ - σ x , where σ is a nonzero real parameter.
