A formulation based on the uniform theory of diffraction (UTD) for the analysis of the multiple-diffraction of a spherical sound wave caused by a series of wedges or knife-edges is hereby presented. The receiver location has to be considered at the same height as the preceding obstacles and at the same inter-obstacle distance from the last wedge. The solution, which is based on a UTD-physical optics formulation for radio-wave multiple-diffraction and has been validated through comparison with a geometrical theory of diffraction acoustic model, is computationally more efficient than other existing methods thanks to the fact that only single diffractions are involved in the calculations (high-order diffraction terms are not considered in the diffraction coefficients), thus allowing for the consideration of a great number of obstacles. In such a way, the proposed solution overcomes the limitations of previous works when multiple acoustic diffraction caused by an array of elements of equal height is to be analyzed. Therefore, the results can be applied in the study of sound propagation in scenarios where multiple-diffraction over a series of edges of equal height and periodical spacing has to be considered, such as the typical audience seating of a concert hall.
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Sci Rep
December 2024
College of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming, 650500, China.
Drug-drug co-amorphous systems are a promising approach to improve the aqueous solubility of poorly water-soluble drugs. This study explores the combination of breviscapine (BRE) and matrine (MAT) form an amorphous salt, aiming to synergistically enhance the solubility and dissolution of BRE. In silico analysis of electrostatic potential and local ionization energy were conducted on BRE-MAT complex to predict the intermolecular interactions, and solvent-free energies were calculated using thermodynamic integration and density functional theory.
View Article and Find Full Text PDFMar Drugs
December 2024
Shandong Laboratory of Yantai Drug Discovery, Bohai Rim Advanced Research Institute for Drug Discovery, Yantai 264117, China.
Two new cembrane-derived tricyclic diterpenes belonging to the sarcophytin family, namely 4-hydroxy-chatancin () and sarcotoroid (), together with two known related ones ( and ), were isolated from the soft coral collected off Ximao Island in the South China Sea. The structures of the new compounds were elucidated by extensive spectroscopic analysis, a quantum mechanical nuclear magnetic resonance (QM-NMR) method, a time-dependent density functional theory electronic circular dichroism (TDDFT-ECD) calculation, X-ray diffraction analysis, and comparison with the reported data in the literature. A plausible biosynthetic pathway of compounds - was proposed, involving undergoing a transannular Diels-Alder cycloaddition.
View Article and Find Full Text PDFChem Sci
December 2024
Frontier Institute of Science and Technology, State Key Laboratory of Electrical Insulation and Power Equipment, MOE Key Laboratory for Nonequilibrium Synthesis of Condensed Matter, Xi'an Key Laboratory of Electronic Devices and Materials Chemistry and School of Chemistry, Xi'an Jiaotong University 99 Yanxiang Road Xi'an Shaanxi 710054 P. R. China
The benzene tetraanion-bridged rare earth inverse arene amidinate complexes [{Ln(κ:η-Piso)}(μ-η:η-CH)] (2-Ln, Ln = Gd, Tb, Dy, Y; Piso = {(NDipp)C Bu}, Dipp = CH Pr-2,6) were prepared by the reduction of parent Ln(iii) bis-amidinate halide precursors [Ln(Piso)X] (Ln = Tb, Dy; X = Cl, I) or [Ln(Piso)I] (Ln = Gd, Y) with 3 eq. KC in benzene, or by the reaction of the homoleptic Ln(ii) complexes [Ln(Piso)] (Ln = Tb, Dy) with 2 eq. KC in benzene.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China.
The exploration of main group compounds with multiple bonds has significantly enhanced our understanding of chemical bonding and expanded transition-metal-free bond activation and catalysis. Diborynes, characterized by a boron-boron triple bond (B≡B), represent a particularly challenging area due to boron's limited valence electrons. Here, we report the synthesis and characterization of a silylene-stabilized diboryne (), expanding the frontier of diboryne stabilization.
View Article and Find Full Text PDFJASA Express Lett
December 2024
Applied Research Laboratories, The University of Texas at Austin, Austin, Texas 78766-9767, USA.
Analytical solutions for acoustic vortex beams radiated by sources with uniform circular amplitude distributions are derived in the paraxial approximation. Evaluation of the Fresnel diffraction integral in the far field of an unfocused source and in the focal plane of a focused source leads to solutions in terms of an infinite series of Bessel functions for orbital numbers ℓ>-2. These solutions are reduced to closed forms for 0≤ℓ≤4, which correspond to orbital numbers commonly used in experiments.
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