Electronic Oscillator Research Articles

Design ultrasonic power generators for welding machines using piezoelectric ceramic materials for welding on non-woven fabrics

This paper presents the design and manufacture of ultrasonic emitters for welding machines using piezoelectric ceramic materials for welding on non-woven fabrics. The ultrasonic vibrating membrane (UVB) used for the transducer is investigated to ensure that there are no cracks in the material structure. These parameters serve as the basis for evaluating the quality of the ultrasonic vibrating membrane in the fabrication of an oscillator for ultrasonic transducer welding (USTW). The ultrasonic power generator (USPG) is made of high-frequency components and power components to supply electrical oscillations to the UVB. This vibrating source must be compatible with the USTW to operate at maximum efficiency. Due to the influence of the manufacturing process and USTW usage environment, after operating for a long time, the resonant frequency (fr) will be changed. Therefore, the USPG needs to monitor the frequency of the USTW automatically. Matching the impedance of USTW and USPG is very important to get the most out of USPG power. The fabrication results show that the use of high-resolution timer to generate the control frequency for USPG achieves high accuracy, with the largest error of 0.006% at 18401.12 Hz when surveyed in the range of 18 to 22 kHz. The parameters of control signal delay between two phases and pulse width also give very good results. Impedance-matching (IM) networks also show good exploitation of USPG when compared to USPG without IM.

Plasmon‐enhanced FRET biosensor based on Tm3+/Er3+ co‐doped core‐shell upconversion nanoparticles for ultrasensitive virus detection

AbstractOutbreaks of infectious viruses offer a formidable challenge to public healthcare systems and early detection of viruses is essential for preventing virus propagation. In this work, an ultrasensitive plasmon‐enhanced fluorescence resonance energy transfer (FRET) biosensor based on core‐shell upconversion nanoparticle (csUCNP) and gold nanoparticle (AuNP) for accurate detection of SARS‐CoV‐2 viral RNA is presented. In this biodetection assay, the Tm3+/Er3+ co‐doped csUCNP NaGdF4:Yb/Tm@NaYF4:Yb/Er acts as an energy donor and AuNP serves as an energy acceptor. The upconversion emission of Tm3+ and the design of the core‐shell structure led to a simultaneous surface plasmon effect of AuNP. The localized surface plasmon resonance (LSPR) arising from collective oscillations of free electrons significantly enhanced FRET efficiency between Er3+ and AuNP. The as‐prepared biosensor obtained a limit of detection (LOD) as low as 750 am, indicating that the integration of FRET and surface plasmon into one biodetection assay significantly boosted the sensitivity of the biosensor. In addition, samples extracted from clinical samples are also utilized to validate the effectiveness of the biosensor. Therefore, this innovative plasmon‐enhanced FRET biosensor based on Tm3+/Er3+ co‐doped csUCNP may pave the way for rapid and accurate biodetection applications.

Fine-tunable ε′-negative response derived from low-frequency plasma oscillation in graphene/polyaniline metacomposites

Remarkable ε′-negative responses at radio-frequency endow metacomposites with revolutionary applications in electromagnetic (EM) fields. However, uncovering its regulation mechanism and subsequently achieving fine-tunable ε′-negative response remains challenging. Here, we meticulously designed graphene/polyaniline (GR/PANI) metacomposites above percolation, which directly enable tunable negative permittivity at an order of magnitude of −103. By rationally adjusting the three-dimensional GR network, we were able to form collective low-frequency plasma oscillation of free electrons in composites, which intrinsically contributes to the tunable ε′-negative response. Moreover, an ε′-near-zero (ENZ) response was surprisingly observed at ∼920 MHz due to the ineffectiveness of the plasmonic state at high frequencies. In addition, we carried out equivalent circuit analysis to demonstrate the phase relationship and electrical characteristics of these metacomposites. This work could contribute to a new category of polymer-matrix composites and enable exotic properties beyond their natural and bulk counterparts.

Capturing Vector Light Field on Azo Molecular Glass Submicron Pillar Array for Polarization Recording and Creating Optical Functional Surfaces

AbstractVector light fields possessing spatial‐variant states of polarization (SOPs) have attracted great research interest for various emerging applications. In this work, the responses of submicron pillar arrays of an azo molecular glass (IA‐Chol) to vector light fields are systematically investigated by using laser beams with different topological charges. The spatial‐variant SOPs in the illuminated areas are recorded by directional pillar deformations along the local electric field oscillation directions, and uncovered by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The degrees of pillar deformations are proven to be correlated to the intensity distributions of the vector beams in the transverse planes. The pillar deformations caused by the vector beam irradiations generate several optical effects related to the surface structures, as revealed by optical microscopy, polarizing optical microscopy, and diffraction measurements. Based on the understanding, structural colors covering a wide spectral range are created for the pillar arrays after irradiated with the vector beams. The complex images with various structural colors are produced by the irradiations with vector beams through photomasks. These investigations reveal the unique correlations between the pillar deformations and transverse polarization morphologies of vector beams and demonstrate a promising approach to fabricate optical functional surfaces.

Intersubband Electronic Oscillations an Armchair Graphene Nanoribbon in the Presence of Bichromatic Light Waves

Intersubband Electronic Oscillations an Armchair Graphene Nanoribbon in the Presence of Bichromatic Light Waves

A Mechanism Underpinning the Bioenergetic Metabolism-Regulating Function of Gold Nanocatalysts.

Bioenergetic deficits are known to be significant contributors to neurodegenerative diseases. Nevertheless, identifying safe and effective means to address intracellular bioenergetic deficits remains a significant challenge. This work provides mechanistic insights into the energy metabolism-regulating function of colloidal Au nanocrystals, referred to as CNM-Au8, that are synthesized electrochemically in the absence of surface-capping organic ligands. When neurons are subjected to excitotoxic stressors or toxic peptides, treatment of neurons with CNM-Au8 results in dose-dependent neuronal survival and neurite network preservation across multiple neuronal subtypes. CNM-Au8 efficiently catalyzes the conversion of an energetic cofactor, nicotinamide adenine dinucleotide hydride (NADH), into its oxidized counterpart (NAD+ ), which promotes bioenergy production by regulating the intracellular level of adenosine triphosphate. Detailed kinetic measurements reveal that CNM-Au8-catalyzed NADH oxidation obeys Michaelis-Menten kinetics and exhibits pH-dependent kinetic profiles. Photoexcited charge carriers and photothermal effect, which result from optical excitations and decay of the plasmonic electron oscillations or the interband electronic transitions in CNM-Au8, are further harnessed as unique leverages to modulate reaction kinetics. As exemplified by this work, Au nanocrystals with deliberately tailored structures and surfactant-free clean surfaces hold great promise for developing next-generation therapeutic agents for neurodegenerative diseases.

MOF-derived ZrO2/C-polyvinylidene fluoride composite towards negative permittivity regulation mechanism

Composites featuring negative permittivity have garnered significant attention for their potential in novel capacitance designs, coil-less electrical inductors, and electromagnetic shielding applications. In this study, we prepared polyvinylidene fluoride (PVDF) matrix composites filled with ZrO2/C nanoparticles derived from metal-organic frameworks (MOFs) via a hot-pressing method. With an increase in the ZrO2/C content to 30 wt.%, electrical percolation was observed, accompanied by a transition mechanism from hopping conduction to metal-like conduction. This enabled the realization of ZrO2/C/PVDF composites with tailorable negative permittivity properties, attributed to the plasmonic oscillation of free electrons in the composites beyond the percolation threshold (30 wt.%). Furthermore, the permittivity transition along to a shift in the electrical behavior of the percolative composites from capacitive to inductive. We explored the regulatory mechanism behind the negative permittivity in this random composite system, and our findings highlight the potential of these tunable negative permittivity media as promising candidates for diverse electromagnetic applications.

Monogamy properties of quantum correlations in neutrino oscillations

The monogamy relation of quantum states has limited the shareability properties of quantum resources in multiparty quantum systems. It plays a vital role in information distribution and transformation over many sites in quantum communications. Here, we focus on the monogamy relations of quantum correlations in the context of three-flavor neutrino oscillations, related to the squared entanglement of formation, the squared of quantum discord and its geometric variant. The monogamy relations in terms of the squared entanglement of formation work for the electron and muon antineutrino oscillations, suggesting that the bipartite entanglement measured by squared entanglement of formation of the three-flavor neutrino system set a limitation to the sum of pairwise squared entanglement of formation. Furthermore, we found that the squared quantum discord is also monogamous in three-flavor neutrino system. As a comparison, we test the monogamy of the quantum discord in neutrino oscillations with the result that the quantum discord is not monogamous. In addition, it is found that the bipartite geometric quantum discord of three-flavor systems is equal to the sum of the pairwise geometric quantum discord, i.e., the monogamy relation for geometric quantum discord is saturated for three-flavor neutrino system. These monogamy relations of quantum correlations provide a way for studying the distribution of quantum resources in neutrino oscillations, which is of significance to explore the further applications of neutrino oscillations in quantum communications.

Nonlocal Soft Plasmonics in Planar Homogeneous Multilayers

Plasmonics is the study of resonant oscillations of free electrons in metals caused by incident electromagnetic radiation. Surface plasmons can focus and steer light on the subwavelength scale. Apart from metals, plasmonic phenomena can be observed in soft matter systems such as electrolytes which we study here. Resonant charge oscillations can be induced for ions in solution, however, due to their larger mass, they are plasmon-active in a lower frequency regime and on a larger wavelength scale. Our investigation focuses on spatial confinement which allows increasingly strong charge interactions and gives rise to nonlocality or spatial dispersion effects. We derive and discuss the nonlocal optical response of ionic plasmons using a hydrodynamic two-fluid model in a planar homogeneous three-layer system with electrolyte-dielectric interfaces. As in metals, we observe the emergence of additional longitudinal propagation modes in electrolytes which causes plasmonic broadening. Studying such systems enables us to identify and understand plasmonic phenomena in biological and chemical systems.

Broadside radiation antenna based on tightly coupled spoof surface plasmon polaritons

A spoof surface plasmon polariton (SSPP) is a hybrid mode of a surface wave in the air and electron oscillation within artificial electromagnetic (EM) media, with the dispersion curve lying below the light line, giving rise to many unique EM properties. In this paper, we investigate the EM properties of tightly coupled SSPP (TC-SSPP) modes and propose a slender broadside antenna based on the TC-SSPP. With the comb structure (CS), dispersion properties of different SSPP modes are firstly analyzed under plane wave illumination, and then we introduce a modified SSPP structure, the broadside-coupled (BC)-CS, to excite and guide TC-SSPP modes. Since TC-SSPP modes can be confined tightly around the slender BC-CS, EM waves can be manipulated within a much more compact space, which is favorable for miniaturization, compactness and the light weight of microwave devices. To demonstrate this, we propose a slender broadside radiation antenna based on the TC-SSPP, using a probe as the feed and a finite-length BC-CS as the radiator. Due to near-field magnetic coupling, the SSPP wave can be excited on the BC-CS. By varying the geometric parameters, the antenna can radiate in the broadside direction. A prototype was designed, fabricated and measured. Both the simulated and measured results verify our design.

Determination of the Dependence of the Oscillation of Transverse Electrical Conductivity and Magnetoresistance on Temperature in Heterostructures Based on Quantum Wells

In this work, the influence of two-dimensional state density on oscillations of transverse electrical conductivity in heterostructures with rectangular quantum wells is investigated. A new analytical expression is derived for calculating the temperature dependence of the transverse electrical conductivity oscillation and the magnetoresistance of a quantum well. For the first time, a mechanism has been developed for oscillating the transverse electrical conductivity and magnetoresistance of a quantum well from the first-order derivative of the magnetic field (differential) at low temperatures and weak magnetic fields. The oscillations of electrical conductivity and magnetoresistance of a narrow-band quantum well with a non-parabolic dispersion law are investigated. The proposed theory investigated the results of experiments of a narrow-band quantum well (InxGa1-xSb).

Impact of Silicon Ion Irradiation on Aluminum Nitride‐Transduced Microelectromechanical Resonators

AbstractMicroelectromechanical systems (MEMS) resonators use is widespread, from electronic filters and oscillators to physical sensors such as accelerometers and gyroscopes. These devices' ubiquity, small size, and low power consumption make them ideal for use in systems such as CubeSats, micro aerial vehicles, autonomous underwater vehicles, and micro‐robots operating in radiation environments. Radiation's interaction with materials manifests as atomic displacement and ionization, resulting in mechanical and electronic property changes, photocurrents, and charge buildup. This study examines silicon (Si) ion irradiation's interaction with piezoelectrically transduced MEMS resonators. Furthermore, the effect of adding a dielectric silicon oxide (SiO2) thin film is unveiled. Aluminum nitride on silicon (AlN‐on‐Si) and AlN‐SiO2‐Si bulk acoustic wave (BAW) resonators are designed and fabricated. The devices are irradiated using 2 MeV Si+ ions at various fluxes up to a total fluence of 5 × 1014 cm−2. A time anneal is conducted to characterize device recovery. Scattering (S‐) parameters are measured in situ. Specific damage coefficients are derived to describe the radiation effect on resonant frequency (fr), quality factor (Q), motional resistance (Rm), and electromechanical coupling factor (). Furthermore, the damage coefficients for the bulk material properties of elastic modulus (E) and the piezoelectric coefficient (d31) are found.

(Invited) Multiscale Interfacial Heterogeneity Explored by Advanced Spectroscopy and Imaging for Batteries Beyond Lithium-Ion

Keywords: solid-liquid interface, solid-state battery, surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS), neutron tomography, sulfide solid-state electrolyte, Raman imagingThe ever-growing needs for energy storage systems require batteries with even higher power and energy density with extended life and enhanced safety beyond the current Li-ion battery technologies. Fulfilling these needs requires new battery chemistries, including high-energy-density electrode materials, solid-state electrolytes, and efficient interphases to mitigate the side reactions between the electrodes and the electrolytes.Charge transport across the electrode and electrolyte interface is believed to be one of the charge/discharge rate-limiting steps. Although the composition, morphology, and structure of solid-electrolyte interphase (SEI) have been extensively studied, probing its evolution at the nanoscale is challenging to a large extent. Plasmon-enhanced Raman spectroscopy (PERS) is promising to solve this challenge. PERS is the resonant oscillation of conduction electrons at the interface between negative and positive permittivity molecules stimulated by incident light. It includes surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS). In the first part of this talk, I will show that gap-mode SERS is ideal to probe salt solvation structure in the immediate vicinity (< 20 nm) of the electrode/electrolyte interface. SERS lacks the nanoscale resolution in the sample plane. This can be compensated by TERS. TERS analysis on cycled high-energy silicon anodes indicates that the nanometer scale SEI "islands" are unevenly distributed. Even for the same SEI "island", the composition is different from point to point with inter-point distance smaller than 10 nm.All-solid-state lithium metal batteries (SSBs) promise specific energy >500 Wh/kg. A solid-state electrolyte (SSE) plays an irreplaceable role in reaching such an energy-density goal. Sulfide-based SSEs have emerged as a prominent class of soft ionic conductors that have comparable room-temperature ionic conductivity to their liquid electrolyte counterparts. However, when paring with a high voltage cathode, such as lithium nickel manganese cobalt oxide (NMC), the (electro)chemical instability of the sulfide SSE at the electrode/SSE interfaces becomes a major challenge. The interfacial instability can result in >50% initial capacity loss in a Li/sulfide SSE/NMC battery, thereby keeping the sulfide SSEs from commercialization. In the second part of this talk, I will show how we synergistically use neutron computed tomography and in situ Raman imaging, with clustering analysis to track lithium displacement at the interface of a sulfide-based SSB. Acknowledgment This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is supported by Asst. Secretary, Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (VTO) through the Advanced Battery Materials Research (BMR) Program. This research used resources at High Flux Isotope Reactor, a DOE Office of Science User Facilities operated by the Oak Ridge National Laboratory.

Dielectric evolution of permittivity transition from positive to negative induced by percolation in ceramic composites

Ceramic composites made up of well-selected components have enriched the varieties of the metamaterials with negative electromagnetic parameters. In this work, TiN/BaTiO3 ceramic composites were prepared with a simple dry-pressing and pressureless sintering process. Percolation was eventually determined to be the key inducements which caused the permittivity of the ceramic composites changing from positive to negative. Essentially, negative permittivity was closely related to the plasma oscillations of free electrons in percolation networks. Meanwhile, conduction mechanism of the composites varied owing to the changes in microstructure, where the percolation networks brought out pathways for electron migration and achieved high conductivity. In addition, ac impedance behavior with changes of the sign for reactance were also discussed, thus the transition from electrical capacitive to inductive for the percolative ceramic composites has been demonstrated. This work clarified the influence of percolation on the conductivity, impedance, and permittivity of ceramic composites altogether. The obtained negative permittivity composites have enormous potential in various electronic devices and electromagnetic apparatus.

EFFECT OF ELECTRON COLLISIONS WITH RESIDUAL NEUTRAL GAS ON CHARACTERISTIC OSCILLATION FREQUENCIES IN SYSTEMS OF ELECTRON FLOWS WITH A VIRTUAL CATHODE

A system of the hydrodynamic equations describing the electron flows in a diode with a virtual cathode is considered. Collisions are considered by introducing the corresponding braking force into the equations of motion. The stationary states of the electron flows are described. In a linear approximation, formulas are obtained for the frequencies of electron oscillations in a diode with a virtual cathode, considering the effective frequency of electron collisions. The expression for the decrement of oscillations due to the presence of collisions is obtained.

Exploration of Coumarin Derivative: Experimental and Computational Modeling for Dipole Moment Estimation and Thermal Sensing Application.

The Optical properties of the FBTC (1-((4-((5-chlorobenzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-3H-benzo[f]chromen-3-one) molecule were studied experimentally and theoretically. The spectra of absorption and fluorescence were recorded in various solvents to explore their Solvatochromic behavior and dipole moment at room temperature. To determine the ground and excited state of dipole moment experimentally and theoretically, we employed different Solvatochromic techniques, including microscopic solvent polarity functions developed by Lippert, Bakhshiev, Kawaski-Chamma-Viallet, and Reichardt's, as well as density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The stability of the excited state dipole moment in FBTC is higher. Using prime functional, FBTC was optimized in its ground state, and its HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital), energies were estimated. These values were then compared with those obtained through cyclic voltammetry. Based on the HOMO and LUMO values given, we calculated the global reactivity parameter and energy gap, which was found to be low at 3.77eV. This study also includes an estimation of electron absorption energies and oscillator strength. Natural population analysis (NPA), Milliken atomic charge, and molecular electrostatic potential (MESP) map are correlated. In addition, FBTC exhibited exceptional physiological temperature sensing behaviour from 20°C -65°C with high relative sensitivity and firm stability. Hence these results confirm that FBTC is a potential candidate for photonic devices and it's also applicable in optical temperature sensing.

DNA and histones impair the mechanical stability and lytic susceptibility of fibrin formed by staphylocoagulase.

Staphylocoagulase (SCG) is a virulence factor of Staphylococcus aureus, one of the most lethal pathogens of our times. The complex of SCG with prothrombin (SCG/ProT) can clot fibrinogen, and SCG/ProT-induced fibrin and plasma clots have been described to show decreased mechanical and lytic resistance, which may contribute to septic emboli from infected cardiac vegetations. At infection sites, neutrophils can release DNA and histones, as parts of neutrophil extracellular traps (NETs), which in turn favor thrombosis, inhibit fibrinolysis and strengthen clot structure. To characterize the combined effects of major NET-components (DNA, histone H1 and H3) on SCG/ProT-induced clot structure, mechanical and lytic stability. Recombinant SCG was used to clot purified fibrinogen and plasma. The kinetics of formation and lysis of fibrin and plasma clots containing H1 or core histones+/-DNA were followed by turbidimetry. Fibrin structure and mechanical stability were characterized with scanning electron microscopy, pressure-driven permeation, and oscillation rheometry. Histones and DNA favored the formation of thicker fibrin fibers and a more heterogeneous clot structure including high porosity with H1 histone, whereas low porosity with core histones and DNA. As opposed to previous observations with thrombin-induced clots, SCG/ProT-induced fibrin was not mechanically stabilized by histones. Similarly to thrombin-induced clots, the DNA-histone complexes prolonged fibrinolysis with tissue-type plasminogen activator (up to 2-fold). The anti-fibrinolytic effect of the DNA and DNA-H3 complex was observed in plasma clots too. Heparin (low molecular weight) accelerated the lysis of SCG/ProT-clots from plasma, even if DNA and histones were also present. In the interplay of NETs and fibrin formed by SCG, DNA and histones promote structural heterogeneity in the clots, and fail to stabilize them against mechanical stress. The DNA-histone complexes render the SCG-fibrin more resistant to lysis and thereby less prone to embolization.

Simulation of temperature dependence of oscillations of longitudinal magnetoresistance in nanoelectronic semiconductor materials

In this work, the influence of two-dimensional state density on oscillations of transverse electrical conductivity in heterostructures with rectangular quantum wells is investigated. A new analytical expression is derived for calculating the temperature dependence of the transverse electrical conductivity oscillation and the magnetoresistance of a quantum well. For the first time, a mechanism has been developed for oscillating the transverse electrical conductivity and magnetoresistance of a quantum well from the first-order derivative of the magnetic field (differential) ∂(ρ⊥2d(E,B,T,d))∂B at low temperatures and weak magnetic fields. The oscillations of electrical conductivity and magnetoresistance of a narrow-band quantum well with a non-parabolic dispersion law are investigated. The proposed theory investigated the results of experiments of a narrow-band quantum well (InxGa1-xSb).

Laser-driven electrodynamic implosion of fast ions in a thin shell

Collision of laser-driven subrelativistic high-density ion flows provides a way to create extremely compressed ion conglomerates and study their properties. This paper presents a theoretical study of the electrodynamic implosion of ions inside a hollow spherical or cylindrical shell irradiated by femtosecond petawatt laser pulses. We propose to apply a very effective mechanism for ion acceleration in a self-consistent field with strong charge separation, based on the oscillation of laser-accelerated fast electrons in this field near the thin shell. Fast electrons are generated on the outer side of the shell under irradiation by the intense laser pulses. It is shown that ions, in particular protons, may be accelerated at the implosion stage to energies of tens and hundreds of MeV when a sub-micrometer shell is irradiated by femtosecond laser pulses with an intensity of 1021–1023 W cm−2.

Coherent-Phonon-Driven Intervalley Scattering and Rabi Oscillation in Multivalley 2D Materials.

Resolving the complete electron scattering dynamics mediated by coherent phonons is crucial for understanding electron-phonon couplings beyond equilibrium. Here we present a time-resolved theoretical investigation on strongly coupled ultrafast electron and phonon dynamics in monolayer WSe_{2}, with a focus on the intervalley scattering from the optically "bright" K state to "dark" Q state. We find that the strong coherent lattice vibration along the longitudinal acoustic phonon mode [LA(M)] can drastically promote K-to-Q transition on a timescale of ∼400 fs, comparable with previous experimental observation on thermal-phonon-mediated electron dynamics. Further, this coherent-phonon-driven intervalley scattering occurs in an unconventional steplike manner and further induces an electronic Rabi oscillation. By constructing a two-level model and quantitatively comparing with abinitio dynamic simulations, we uncover the critical role of nonadiabatic coupling effects. Finally, a new strategy is proposed to effectively tune the intervalley scattering rates by varying the coherent phonon amplitude, which could be realized via light-induced nonlinear phononics that we hope will spark experimental investigation.