Resonant Excitation Research Articles

Photoelectron spectroscopy of deprotonated benzonitrile.

The recent discovery of cyano-substituted aromatic and two-ring polycyclic aromatic hydrocarbon molecules in Taurus Molecular Cloud-1 has prompted questions on how the electronic structure and excited-state dynamics of these molecules are linked with their existence and abundance. Here, we report a photodetachment and frequency- and angle-resolved photoelectron spectroscopy study of jet-cooled para-deprotonated benzonitrile (p-[Bzn-H]-). The adiabatic detachment energy was determined as 1.70 ± 0.01eV, in good agreement with CCSD(T)/aug-cc-pVTZ calculations. The spectra across the first few electron-volts above threshold are dominated by prompt autodetachment processes associated with excitation of at least five short-lived (tens of femtoseconds) temporary anion shaped resonances since excitation cross sections are several orders of magnitude larger than direct photodetachment cross sections. The photoexcitation vibronic profile is dominated by a ≈640 cm-1 ring deformation mode. [Bzn-H]- lacks a valence-localized excited state situated below the detachment threshold and does not exhibit thermionic emission following excitation of the temporary anion resonances. Thus, [Bzn-H]- is unlikely to be stable in many interstellar environments.

Pushing the Limits of Photoconductivity via Hot Electrons in Deep Trap States in Plasmonic Architectures.

Although extensive research on the mechanisms of photoconductivity enhancement in plasmonic Schottky structures has been conducted, the photoconductive interplay between hot electrons and trapping states remains elusive. In this study, we explored the photoconductive relationship between plasmonic hot-carriers and defect sites present in plasmonic architectures consisting of N-face n-GaN and Au nanoprisms. Our experimental results clearly verified that the plasmonic hot-electrons generated by interband transitions preferentially occupied deep trap levels in n-GaN, thereby considerably enhancing the photoconductivity through the combination of photogating and photovoltaic effects. Our quantitative evaluation demonstrated that a mere 63% increase in hot-electron trapping leads to a 1.7-fold increased photocurrent under localized surface plasmon resonance (LSPR) excitation compared to the figure of photocurrent under non-LSPR stimulus. Our findings provide novel insights into the mechanisms of photoconductive enhancement for advanced plasmonic applications.

Magnetic field enhanced terahertz emission from metallic nanostructures with response to laser spatial profile distribution

This communication proposes an analytical model that exhibits terahertz (THz) radiation generation from spatially corrugated noble-metal spherical and cylindrical nanoparticles (NPs) placed under the influence of an externally applied static magnetic field. This scheme involves the resonant excitation of THz radiation through the beat-wave of two lasers in the presence of ponderomotive nonlinearities. Effect of magnetic field as well as laser intensity profiles, which include super, cosh, flat-top and ring-shaped Gaussian profiles, have been investigated. The incorporation of the magnetic field induces substantially more dynamic laser-metal coupling and influences the surface plasmon resonance condition associated with electrons of the NPs, thereby leading to stronger THz emission. Our results also demonstrate that the spatial profile of the laser affects the THz output, as it impacts the excitation and dynamics of the NPs. Additionally, we find that both the shape, size and interparticle-separation of NPs play crucial roles in enhancing THz generation. Furthermore, we explore the effects of varying other parameters like electric field strength and beam waist of incident lasers. These findings provide valuable insights for the design and optimization of THz sources based on NP systems, offering new avenues for applications in spectroscopy, imaging, communication and biomedical sciences.

Multiphoton Resonance Meets Tunneling Ionization: High-Efficient Photoexcitation in Strong-Field-Dressed Ions.

Tunneling ionization, a fascinating quantum phenomenon, has played the key role in the development of attosecond physics. Upon absorption of a few tens of photons, tunneling ionization creates ions in different excited states and even enables the formation of population inversion between ionic states. However, the underlying physics is still being debated. Here, we demonstrate a significant enhancement in the efficiency of multiphoton excitation when ionization of neutral molecules and resonant excitation of ions coexist in strong laser fields. It facilitates the dramatic increase in population inversion and lasing radiation in N_{2}^{+} around 1000nm pump wavelength. Utilizing the ionization-coupling theory, we discover that the synergistic interplay between tunneling ionization and multiphoton excitation enables the ionic coherence to be maximized by phase locking of the periodically created ionic dipoles and consistently maintain an optimal phase for the follow-up photoexcitation. This Letter provides new insights into the photoexcitation mechanism of ions in strong laser fields and opens up a route for optimizing ionic lasing radiations.

Trembling Motion of Exciton Polaritons Close to the Rashba-Dresselhaus Regime.

We report the experimental observation of trembling quantum motion, or Zitterbewegung, of exciton polaritons in a perovskite microcavity at room temperature. By introducing liquid-crystal molecules into the microcavity, we achieve spinor states with synthetic Rashba-Dresselhaus spin-orbit coupling and tunable energy splitting. Under a resonant excitation, the polariton fluid exhibits clear trembling motion perpendicular to its flowing direction, accompanied by a unique spin pattern resembling interlocked fingers. Furthermore, leveraging the sizable tunability of energy gaps by external electrical voltages, we observe the continuous transition of polariton Zitterbewegung from relativistic (small gaps) to nonrelativistic (large gaps) regimes. Our findings pave the way for using exciton polaritons in the emulation of relativistic quantum physics.

Damage assessment in composite plates using extended non-destructive self-heating based vibrothermography technique

Self-heating based vibrothermography (SHVT) is a promising non-destructive technique for inspecting polymer-matrix composites (PMCs) in circumstances with limited external heating feasibility, functioning under the resonant frequency excitation. This study broadened the applicability of SHVT technique for two-dimensional (2D) PMCs by examining its sensitivity and effectiveness in detecting and quantifying damage within 2D laminated composites across nine different scenarios. Atwo-step algorithm based on the concepts of the boundary of effective thermograms, and the maximal temperature ratio was proposed to methodically choose the optimal raw thermogram from a large set of registered thermograms for each scenario. The issues linked to blurred damage signatures in the raw infrared (IR) images adversely affected the overall sensitivity and accuracy of SHVT. Implementing the algorithm based on central moments improved the overall damage detectability using this technique. Additionally, the introduced hit/miss metric enabled the damage identification and quantification for all scenarios.

Ultra-low-thickness, highly sensitive, and perfect-absorption THz refractive index and temperature sensors based on Tamm plasmon polaritons and Fabry-Perot resonators

In this paper, an ultra-low thickness with high sensitivity and perfect absorption based on the excitation of Tamm plasmon polaritons and Fabry-Perot resonance for sensing applications is presented. The sensor comprises a graphene sheet, a spacer layer, an analyte region, and a one-dimensional periodic stack of the dielectric and metal layers. The sensor’s performance is evaluated using the transfer matrix method under different conditions, including the presence of the graphene sheet and metallic layers of the periodic stack, a change in the chemical potential of the graphene sheet, the thickness of the layers, as well as the incident polarization and angle. The simulation results show that the presence of the graphene sheet causes stimulation of Tamm plasmon polaritons, and the presence of metal layers simultaneously increases the absorption and decreases the thickness of the sensor. The sensitivity of the sensor is 0.9667 THz/RIU (equivalent to 305 μm/RIU) with an absorption peak of 99.99 %. The use of silicon as the analyte allows the proposed structure to perform as a temperature sensor in the range of 1 THz, which results in a temperature sensitivity of 0.055 THz/°C (equivalent to 16.45 nm/°C). The proposed sensor has the advantages of extremely thin thickness, perfect absorption, high sensitivity, tunability, and fabrication-friendly structure. The proposed sensor has high potential for use in various sensing applications.

Stretchable Metamaterials with Tunable Infrared Emissivity for Dynamic Thermal Management.

Manipulation of infrared emissivity, which is closely related to surface structure and optical parameters of materials, is a crucial approach for realizing dynamic thermal management. In this study, we design a metamaterial consisting of an array of aluminum disks embedded on a surface of a stretchable elastomeric substrate. Mechanical stretching-induced deformation allows dynamic modification of the surface structure and equivalent optical parameters, thus enabling dynamic control of the emissivity. By utilizing the elastomer polydimethylsiloxane (PDMS) as the substrate, the microstructure interdisk gap can be altered by stretching the PDMS. Through theoretical calculations, the plausibility of this approach is explained by the excitation of plasmon resonance and the variation in the exposed area of highly absorbent PDMS, and the optimal structures for tuning the infrared emissivity are revealed to be 6 μm in diameter and 100 nm in height. Based on this design, we prepare samples with periods of 7 and 7.9 μm and experimentally demonstrate that a change in the period can cause a change in the emissivity and thus tunability in thermal control performance. The temperature difference between the two samples reaches 44.1 °C at a heating power of 0.28 W/cm2 for both samples. Furthermore, we construct a stretching platform that enables in situ mechanical stretching to realize dynamic changes in emissivity. The integral infrared emissivity of the sample increases from 0.32 to 0.5 at a biaxial tensile strain of 13%, achieving a 56% modulation rate of the integral infrared emissivity. The material is expected to enable dynamic thermal management.

Metallic nanoentities: Bio-engineered silver, gold, and silver/gold bimetallic nanoparticles for biomedical applications

This present study reports the biogenic synthesis of silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) and Ag/Au bimetallic nanoparticles (BNPs) using bark extract of plant Tamarix aphylla (T.A). The bark extract contained total polyphenolic compounds and total flavonoids as 0.0362 mg/mg and 0.2928 mg/mg of the dried bark extract respectively. Silver nitrate (AgNO3) and hydrogen tetra chloroaurate trihydrate (HAuCl4.3H2O) were used as precursors while deionised water and methanol (CH3OH) were used as solvents. Synthesized nanoparticles were characterized through UV–visible spectroscopy, SEM (scanning electron microscopy), TEM (transmission electron microscopy) and FTIR (Fourier transform infrared) for their morphology, structure, and identification of different functional groups. The UV–visible spectra of AgNPs, AuNPs and Ag/Au BNPs showed peaks at 436, 532 and 527 nm respectively due to the excitation of Surface Plasmon Resonance. SEM and TEM images showed spherical and well distributed nanoparticles (NPs) with particle size as 29 nm (AgNPs), 13 nm (AuNPs) and 26 nm (Ag/Au BNPs). The synthesized NPs are significantly active against inhibition of free radicals, α-amylase, α-glucosidase and have anti inflammatory potential with AgNPs having the highest percent activity at 400 μg/ml, followed by Ag/Au BNPs. The same trend (AgNPs > Ag/AuBNPs > AuNPs) has been observed at all concentrations i.e. 100 μg/ml, 200 μg/ml and 400 μg/ml. AuNPs have shown lowest activity at all concentrations. So the current study strongly confirms use of T.A bark extract as reducing agent for synthesis of metal NPs and opens up a new possibility of using these green synthesized NPs as biomedicines. We also suggest further in vivo investigation to report any side effects if present.

Green Synthesis of CuO Nanoparticles Mediated Rhazya Stricta Plant Leaves Extract Characterization and Evaluation of their Antibacterial and Anticancer Activity (in vitro Study)

In this study, a straightforward, expeditious, and environmentally friendly approach to synthesize copper oxide nanoparticles (CuONPs) utilizing an aqueous extract of Rhazya Stricta (R. stricta) leaves was employed. The CuONPs underwent various analytical techniques for characterization, including X-ray diffractometer (XRD), field emission scan electron microscope (FESEM), energy dispersive X-ray (EDX) analyses, UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and zeta potential. The XRD analysis authenticated the monoclinic crystal nature, revealing an average crystallite size of 15.6 nm. FESEM images depicted semi-spherical and cubic shapes, with particle sizes ranging from 56.64 to 86.95 nm. The formation of CuONPs was initially confirmed by the observable change in colour, attributed to the excitation of surface Plasmon resonance at 280 nm in the UV-Vis spectra. FTIR analysis affirmed the presence of functional groups in the R. Stricta leaves extract, serving as both reducing and stabilizing agents, facilitating the formation of CuONPs. Zeta potential measurements indicated substantial stability with a value of 46.6 mV. The biosynthesized CuONPs were further evaluated for their antibacterial properties against Klebsiella Pneumoniae (K. pneumoniae) and Staphylococcus aureus (S. aureus), yielding inhibition zones of 21 mm and 30 mm, respectively. Additionally, the cytotoxicity assessment of CuONPs against A549 cell lines revealed higher cytotoxicity of 81.47 ± 1.517 at a CuONP concentration of 100 μg/ml. This work is the first attempt at R. stricta-facilitated synthesis of CuONPs as antibacterial and anticancer agents. It can subsequently be exploited as a potential candidate for these agents and might be utilized further in vivo studies.

Elevating electron energy gain and betatron x-ray emission in proton-driven wakefield acceleration

The long proton beams present at CERN have the potential to evolve into a train of microbunches through the self-modulation instability process. The resonant wakefield generated by a periodic train of proton microbunches can establish a high acceleration field within the plasma, facilitating electron acceleration. This paper investigates the impact of plasma density on resonant wakefield excitation, thus influencing the acceleration of a witness electron bunch and its corresponding betatron radiation within the wakefield. Various scenarios involving different plasma densities are explored through particle-in-cell simulations. The peak wakefield in each scenario is calculated by considering a long pre-modulated proton driver with a fixed peak current. Subsequently, the study delves into the witness beam acceleration in the peak wakefield and its radiation emission. Elevated plasma density increases both the number of microbunches and the accelerating gradient of each microbunch, consequently resulting in heightened resonant wakefield. Nevertheless, the scaling is disrupted by the saturation of the resonant wakefield due to the nonlinearities. The simulation results reveal that at high plasma densities, an intense and broadband radiation spectrum extending into the domain of the hard x-rays and gamma rays is generated. Furthermore, in such instances, the energy gain of the witness beam is significantly enhanced. The impact of wakefield on the witness energy gain and the corresponding radiation spectrum is clearly evident at elevated densities.

Broadband light trapping in perovskite solar cells: Optimization and enhancement through exploiting multi-resonant Mie resonators

We present multi-resonant Mie resonators comprising dielectric nanopyramid arrays (DNPAs) for efficient broadband light trapping (LT) in perovskite solar cells (PSCs). Absorption in a 100 nm-thick active layer is significantly enhanced over a broad range of wavelengths through the simultaneous resonant excitation of electric and magnetic moments. Through optimization, a PSC integrated with a front-located DNPA LT structure having a base edge of 320 nm and a spacing of 180 nm at an aspect ratio of 1.5 yields a short-circuit current density (Jsc) of 18.13 mA/cm2, which is about 29 % higher than that of a planar PSC. Multipole resonance contributions and radiation patterns of DNPs are also investigated. The spectral overlap of the multipole resonances of the DNPAs can be easily tuned, thereby providing performance enhancements in diverse applications, such as nanoantennas, metasurfaces, photodiodes, and other solar cells.

Topological Optical Waveguiding of Exciton‐Polariton Condensates

Abstract1D models with topological non‐trivial band structures are a simple and effective way to study novel and exciting concepts in topological photonics. In this work, the propagation of light‐matter quasi‐particles, so‐called exciton‐polaritons, is studied in waveguide arrays. Specifically, topological states are being investigated at the interface between dimer chains, characterized by a non‐zero winding number. In order to exercise precise control over the polariton propagation, non‐resonant laser excitation, as well as resonant excitation, are studied in transmission geometry. The results highlight a new platform for the study of quantum fluids of light and non‐linear optical propagation effects in coupled semiconductor waveguides.

Development of an Earth-Field Nuclear Magnetic Resonance Spectrometer: Paving the Way for AI-Enhanced Low-Field Nuclear Magnetic Resonance Technology.

Today, it is difficult to have a high-field nuclear magnetic resonance (NMR) device due to the high cost of its acquisition and maintenance. These high-end machines require significant space and specialist personnel for operation and offer exceptional quality in the acquisition, processing, and other advanced functions associated with detected signals. However, alternative devices are low-field nuclear magnetic resonance devices. They benefit from the elimination of high-tech components that generate static magnetic fields and advanced instruments. Instead, they used magnetic fields induced by ordinary conductors. Another category of spectrometers uses the Earth's magnetic field, which is simple and economical but limited in use. These devices are called Earth-Field Nuclear Magnetic Resonance (EFNMR) devices. This device is ideal for educational purposes, especially for engineers and those who study nuclear magnetic resonance, such as chemistry or other experimental sciences. Students can observe their internal workings and conduct experiments that complement their education without worrying about damaging equipment. This article provides a detailed explanation of the design and construction of electrical technology devices for the excitation of atomic spin resonance using Earth's magnetic fields. It covers all necessary stages, from research to analysis, including simulation, assembly, construction of each component, and the development of comprehensive software for spectrometer control.

Enhanced light confinement in nonlocal resonant metasurfaces with weak multipolar scatterers

Stronger light confinement can be enabled by nanoantennas in the nanostructure and result in efficient control of the directionality of the scattering. We report on an observation of the well-pronounced multipolar resonances from nickel nanoantennas originating from collective effects. We show that the collective coupling of multipolar modes from weak scatterers can substantially enhance the electric dipole and quadrupole resonances. We also demonstrate the generalized lattice Kerker effect in this nanoantenna array. Resonant multipolar excitations within nickel nanoantenna arrays can significantly enhance phenomena such as magneto-optical effects, indicating promising potential for advanced applications in the field of nanophotonics and sensing.

Enhanced intrinsic chiroptical response of resonant metallic metasurfaces.

The physics of resonant metasurfaces underpins many electromagnetic functionalities with enhanced performance by virtue of resonant excitations. Resonances originating from bound states in the continuum (BICs) were recently recognized in photonics for their superior optical properties, strong local field enhancement, and suppression of radiative losses. Very recently, a concept of intrinsically chiral dielectric BIC metasurfaces was proposed that combines strong narrowband resonant features with the polarization control of scattered light. Here, we design a resonant chiral metallic metasurface supporting a BIC resonance in the microwave wavelength range. In our structure, the metasurface units (meta-atoms) are characterized with rotational and mirror spatial symmetries. We numerically characterize metasurface mode properties in eigenmode calculations and scattering spectra for linearly polarized excitation under oblique incidence. Then, we investigate intrinsic chiroptical effects for transmission of normally propagating excitation beams by breaking the meta-atom in-plane mirror symmetries. We predict that the intrinsic circular dichroism in such structures may exceed 0.74.

Dynamical phase-field model of cavity electromagnonic systems

Cavity electromagnonic system, which simultaneously consists of cavities for photons, magnons (quanta of spin waves), and acoustic phonons, provides an exciting platform to achieve coherent energy transduction among different physical systems down to single quantum level. Here we report a dynamical phase-field model that allows simulating the coupled dynamics of the electromagnetic waves, magnetization, and strain in 3D multiphase systems. As examples of application, we computationally demonstrate the excitation of hybrid magnon-photon modes (magnon polaritons), Floquet-induced magnonic Aulter-Townes splitting, dynamical energy exchange (Rabi oscillation) and relative phase control (Ramsey interference) between the two magnon polariton modes. The simulation results are consistent with analytical calculations based on Floquet Hamiltonian theory. Simulations are also performed to design a cavity electro-magno-mechanical system that enables the triple phonon-magnon-photon resonance, where the resonant excitation of a chiral, fundamental (n = 1) transverse acoustic phonon mode by magnon polaritons is demonstrated. With the capability to predict coupling strength, dissipation rates, and temporal evolution of photon/magnon/phonon mode profiles using fundamental materials parameters as the inputs, the present dynamical phase-field model represents a valuable computational tool to guide the fabrication of the cavity electromagnonic system and the design of operating conditions for applications in quantum sensing, transduction, and communication.

Coherent control of rare earth 4f shell wavefunctions in the quantum spin liquid Tb2Ti2O7

The resonant excitation of electronic transitions with coherent laser sources creates quantum coherent superpositions of the involved electronic states. Most time-resolved studies have focused on gases or isolated subsystems embedded in insulating solids, aiming for applications in quantum information. Here, we focus on the coherent control of orbital wavefunctions in the correlated quantum material Tb2Ti2O7, which forms an interacting spin liquid ground state. We show that resonant excitation with a strong THz pulse creates a coherent superposition of the lowest energy Tb 4f states. The coherence manifests itself as a macroscopic oscillating magnetic dipole, which is detected by ultrafast resonant x-ray diffraction. We envision the coherent control of orbital wavefunctions demonstrated here to become a new tool for the ultrafast manipulation and investigation of quantum materials.

Amplitude analysis and branching fraction measurement of B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} decays

The decays of the B+ meson to the final state D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb−1. The ratio of branching fractions of the B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} and B0→D∗−Ds+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^0\ o {D}^{\\ast -}{D}_s^{+} $$\\end{document} decays is measured to be 0.173 ± 0.006 ± 0.010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed Ds∗+→Ds+γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{\\ast +}\ o {D}_s^{+}\\gamma $$\\end{document} and Ds+π0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{+}{\\pi}^0 $$\\end{document} decays, the ratio of branching fractions between the B+→D∗−Ds∗+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{\\ast +}{\\pi}^{+} $$\\end{document} and B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} decays is determined as 1.31 ± 0.07 ± 0.14. An amplitude analysis of the B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D*−π+ final state. No significant evidence of exotic contributions in the Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{+}{\\pi}^{+} $$\\end{document} or D∗−Ds+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}^{\\ast -}{D}_s^{+} $$\\end{document} channels is found. The fit fraction of the scalar state Tcs¯0∗2900++\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {T}_{c\\overline{s}0}^{\\ast }{(2900)}^{++} $$\\end{document} observed in the B+→D−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{-}{D}_s^{+}{\\pi}^{+} $$\\end{document} decay is determined to be less than 2.3% at a 90% confidence level.

The Vibration Characteristics Analysis of Fiber-Reinforced Thin-Walled Conical–Cylindrical Composite Shells with Artificial Spring Technique

In this paper, the vibration characteristics (free vibration and forced vibration) of fiber-reinforced thin-walled conical–cylindrical composite shells (FTCCS) are analyzed by combining theory and experiment. Based on the classical shell theory and Kirchhoff–Love assumption, the overall structure of the FTCCS is theoretically modeled. The artificial spring technology is used to simulate the arbitrary boundary conditions at the joint, which is divided into a main spring and a secondary spring. At the same time, the displacement functions of the two sub-structure shells of the FTCCS are established by the orthogonal polynomial method, and the energy function of the FTCCS is constructed according to the continuity condition of the bolt joint. Then, the vibration characteristics of the FTCCS are solved using the Rayleigh–Ritz method and the modal superposition method. Finally, the TC300/epoxy resin-based fiber-reinforced thin-walled conical–cylindrical composite shells are selected as the research object, and the rationality of the mathematical model is verified by pulse, frequency sweeping and resonance excitation tests. The experimental results show that the errors between the natural frequency and the resonance displacement calculated by the theory and the experimental results are 1.75–4.76% and 3.79–9.28%, which confirms the rationality of the proposed model. By changing the length of the shell, the lamination angle and the semi-cone angle of the conical shell, the vibration characteristics parameters under different conditions are calculated to evaluate the influence of three physical parameters on the vibration characteristics of the FTCCS.