Separate Excitation Research Articles

A new type of dual-branch composite structure-based ultrasonic transducer for microelectronic interconnection and packaging

A new type of composite structure-based ultrasonic transducer was proposed and a complete set of design methods was systematically developed. The transducer adopts a cascaded structure of two tapered ultrasonic horns and a piezoelectric resonator which involves two groups of piezoceramic stacks. The performance test experiments show that the newly proposed transducer can provide dual-directional vibration output either in a separate excitation of one stack or in a simultaneous excitation of two stacks, depending on which it is expected to execute different bonding tasks in the meanwhile. Particularly in a simultaneous excitation pattern, the salient features in the energy superposition and power-sharing enable the transducer to cope with a higher power-required occasion without rising the input power of any branch transducer, avoiding the potential risk of performance deterioration caused by the excessive self-heating of the piezoceramic stack due to a long-term operation. The test results also show that the newly proposed transducer possesses a good deal of flexibility, manifesting the feasibility and effectiveness of the design idea, as well as the relevant design method, and giving the transducer a wider application prospect.

ANALYSIS OF SYNCHRONOUS GENERATOR ANGULAR STABILITY DEPENDING ON THE CHOICE OF THE EXCITATION SYSTEM

The paper elaborates on the mathematical model of the electric power system with several synchronous generators and in this model the generators are presented by a non-linear mathematical model. By applying such a model, the impact of the manner of supplying the excitation system on the generator’s angular stability was researched in the circumstances of occurrence of a short circuit in the network. The established model enables the analysis of the generator’s stability in the circumstances of extensive disruptions in the electric power system for the case of the generator with separate excitation and the generator with self-excitation. Research results can be useful when making the decision on the choice of the generator excitation type, when renewing the existing and building new generators.

Analytical stochastic framework for assessment of base- and mass-excited structures under equal input energy pertinent to multi-hazard engineering

ABSTRACT Analytical framework for probabilistic assessment of dynamical system under base- and mass- excitations with equal input energy is presented with reference to multi-hazard engineering. Closed-form solutions for equivalent undamped and damped dynamical systems under harmonic sinusoidal base- and mass- excitations are obtained. Uncertainties are considered in the excitation frequency and peak amplitude for sinusoidal base excitations, whereas for the mass excitations, the input forcing functions have variations in excitation frequency, mean speed, and fluctuating wind speeds. Dynamic response quantities (acceleration and displacement) are obtained under the suite of stochastic base and mass excitation forces. Structural failure under the independent excitations is determined as joint probability density functions and fragility surfaces. Under equal input energy from such separate dynamic excitations, dissimilar vulnerability is exhibited by the structure when exposed to two independent time-dependent excitations, base-induced earthquake and mass-induced wind forces. Moreover, the uncertainty in the input excitation parameters has significant influence on the probability of failure in the design life of structure under the non-simultaneous excitations.

Environmental friendly nano-star CdS coupled ZnS on bi-polymer matrix: Unravelling defects-rich nanoplatform for ultrahigh white light active direct S-scheme photodegradation of organic pollutants

Photocatalysis is a reliable technology to treat polluted wastewater. Herein, we report S-scheme photocatalyst namely ZnS/CdS nanocomposites (NCs) with S-vacancies and interstitial defect states, immobilised on the polymer matrix of cellulose and chitosan. It showed significant performance in photocatalytic degradation of Rhodamine B (RhB) dye. Defect sites present in ZnS facilitates charge separation and two-photon excitation concomitantly with a bandgap shift in ZnS/CdS NCs to 2.65 eV and promotes visible light harvesting. XRD analysis demonstrated the highly crystalline nature of the NCs. TEM and SEM were used to observe the crystal phases, particle morphology and defect sites. XPS and EDAX ensured the composition and purity of the synthesized NCs. FTIR displayed the peaks representing the bonds present in metal sulphides and chitosan/cellulose matrix. The photodegradation of RhB by ZnS/CdS NCs reached a maximum of 99.18% in 120 min which displayed 6.8 and 10.25 times higher rate than pure ZnS and CdS respectively. Further, ZnS/CdS NCs was able to achieve the TOC reduction of 86% after the photodegradation of RhB. Defect engineering played a vital role in enhancing the photocatalytic activity of NCs. PL spectra revealed the prolonged life time of photogenerated charge carriers and EIS analysis was used to investigate the charge mobility of the fabricated materials. Superoxide radical was found to be the major radical involved in photodegradation of RhB by NCs. The degradation pathway of RhB was elucidated based on GC-MS/MS analysis. The recyclability of NCs was tested for six consecutive cycles and remarkable stability was observed. The results of in vitro cytotoxicity assay, and cellular reactive oxygen species generation suggest that ZnS/CdS NCs are safety photocatalysts to environment and human being.

Multi-Component Electroacoustic Waves (Mceaw) In Piezo Crystalline Textures: Applied Opportunities

In this paper is shown, that in each sagittal plane of the piezoelectric texture, both the one-component elastic shear wave and the two-component elastic plane deformation wave can be accompanied by either oscillations of the transverse component of the electric field or oscillations of the plane electric field. Four such packets of multicomponent electroelastic waves are formed.Necessary and sufficient conditions are obtained that allow the formulation of a two-dimensional problem of electroelasticity in a vibrated sagittal plane of a piezocrystal, where separate excitation and propagation of a multicomponent quasistatic electroelastic wave is possible.

Controlling and monitoring of a solar-powered DC motor using a wireless sensor network

Due to the economic challenges of soaring oil costs and natural concerns, India faces an enormous growth in renewable energy resources. The solar photovoltaic technology, as a clean and green energy source, plays a critical role in addressing any country’s power shortage. Before mounting a PV system at any location, modeling, simulation, and analysis of solar photovoltaic (PV) generators is a critical phase that helps to understand the behavior and characteristics of the system in real-world climatic conditions. A solar panel, buck–boost converter, separately excited (S.E) DC motor, and controllers, such as Proportional Integral Derivative (PID), Fuzzy, fuzzy based on PID (FPID), and Artificial Neural Network (ANN) controllers are all included in the proposed system. Because compared to other controllers, the ANN controller produces better results. It was designed to deal with system non-linearity and system-related ambiguity. Wireless sensor network (WSN) and Data Dashboard for LabVIEW are used to monitor and control the system.

Time-resolved and temperature-dependent spectroscopy for blue luminescence of monoclinic YSiO2N:Ce3+ phosphor

The monoclinic YSiO2N activated with Ce3+ ions was synthesized, and its luminescence spectra were investigated to reveal the energy level structure of the Ce3+: 5d excited states. Depending on excitation wavelengths, two types of photoluminescence bands in violet and blue regions are observed, which differ in spectral shapes and thermal quenching behaviors. While one of them can easily be assigned to the Ce3+: 5d1 → 2F5/2, 2F7/2 transitions from the major sites, the other shows an anomalously broad weak luminescence band for the latter band. The time-resolved spectroscopy shows a luminescence lifetime distribution of 33–58 ns in the range of 440–540 nm that is also typical for the Ce3+: 5d1 levels. It is suggested that the broad luminescence bands and the distribution of Ce3+ luminescence lifetimes are due to various minor Ce3+ centers with slightly different coordination environments probably caused by intrinsic or anti-site anion defects. By analyzing the temperature dependence of decay curves for Ce3+: 5d luminescence, the activation energy for thermal quenching and the quenching temperature are estimated to be 0.272 eV and 422 K, respectively. The vacuum-UV spectroscopy found out the five separated 5d excitation levels, leading to the estimated centroid energy of 5d levels, 33112 cm−1.

Dual-Polarized Patch Antenna Excited Concurrently by a Dual-Mode Substrate Integrated Waveguide

In this work, we propose and demonstrate an integrated dual linearly polarized cavity-backed patch antenna, which is excited by a concurrent dual-mode substrate integrated waveguide (SIW) structure. For the first time, we have exploited the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> modes of a traveling wave in a dual-mode SIW configuration to excite the horizontal and vertical polarizations of the patch antenna. The proposed methodology yields a low-profile structure with a high interport isolation thanks to the inherent symmetry of the structure. Measurement results indicate an isolation performing better than 42 dB over a 600 MHz impedance bandwidth of the antenna. Moreover, a methodology is developed to implement transitions from the dual-mode SIW to the two different TEM transmission lines for separate but concurrent excitations of the device. Detailed field and impedance analyses are presented to explain the operation principle of the proposed antenna, which are supported by an excellent agreement between the obtained measurement and simulation results.

A broadband piezo-electromagnetic hybrid energy harvester under combined vortex-induced and base excitations

Wind energy harvesting is a green and advanced technology to persistently prop up low-power devices employed in wireless applications. For enhancing the capacity of vortex-induced vibration energy harvester, a broadband piezo-electromagnetic hybrid energy harvester is proposed. The harvester consists of two working units, a piezoelectric unit, and an electromagnetic unit, to concurrently scavenge the vortex-induced and base excitation vibration energy. And magnetic force is the main factor for connecting the two units. The harvester is studied by the methods of theoretical analysis and experimental measurement. Through comparing the experimental results and theoretical analysis, the accuracy of theoretical modeling is proved. And the output characteristic comparisons between the two separate excitations are presented through the theoretical method. Under the combined excitation of vortex-induced and base excitations, the harvester can obtain 1242.86% higher output power and 400% wider operating band compared with the single vortex-induced vibration. The performances of the proposed wind energy harvester under concurrent base and vortex-induced excitations are significantly greater than those based on the single excitation, which provides a good prospect for further exploring the energy harvesting system with multiple excitation sources.

Shell-model study of titanium isotopic chain with chiral two- and three-body forces

The even-even Ti isotopic chain, from $A=42$ to 70, has been studied within the nuclear shell-model framework by employing an effective Hamiltonian which is derived by way of many-body perturbation theory from a chiral potential with two- and three-body forces, and includes three-body contributions which account for Pauli principle violations in nuclei with more than two valence particles. We consider $^{40}\mathrm{Ca}$ as a closed core and a model space spanned by the neutron and proton $0f1p$ orbitals with the addition of the $0{g}_{9/2}$ orbital for neutrons. Calculated two-neutron separation energies and excitation energies of the yrast ${2}^{+}$ states are reported and compared with the experimental data, which are available up to $^{62}\mathrm{Ti}$. The present study intends to investigate the effects of the adopted effective interactions on the evolution of the shell structure.

Studi Karakteristik Luar Dan Efisiensi Generator Dc Penguat Terpisah Terhadap Perubahan Beban Dengan Menggunakan Metode Fuzzy Logic

A DC generator is a dynamic electrical system that converts mechanical energy into electrical energy. A free and separate excitation type DC generator is a generator whose field winding can be connected to a DC source. The power source is independent of the engine. The DC voltage field coils mounted on the form of resistance Rf will generate currents If and cause flux on both poles. The induced voltage will be generated in the generator. The load characteristics of a DC generator show the relationship between the terminal voltage Vt and the field current If when the generator is loaded. When the generator is loaded, a load current will flow IL. In this study, the calculation method used is fuzzy logic, Mamdani. The results obtained when loaded with a field current of 1.2 Amp measured a clamping voltage of 123.5 Volt with a load of 100 watts. When 1.1 Amp lowered the current, the clamping voltage decreased to 120.6 Volt with a load of 100 watts. In comparison, the results of fuzzy logic in 1.2 Amp field current-induced voltage is 128 Volts with a load of 100 watts, so the average percentage difference is 6.74%. To calculate efficiency at a field current of 1.2 Amp load of 100 watts, the resulting efficiency is 44.22%, the greater the load, the smaller the efficiency value. While the efficiency results generated using fuzzy logic are 43.9% with a field current of 1.2 Amp and a load of 100 watts, the average value of the difference is 1.17%.&#x0D;

Z2 lattice gauge theories and Kitaev's toric code: A scheme for analog quantum simulation

Kitaev's toric code is an exactly solvable model with $\mathbb{Z}_2$-topological order, which has potential applications in quantum computation and error correction. However, a direct experimental realization remains an open challenge. Here, we propose a building block for $\mathbb{Z}_2$ lattice gauge theories coupled to dynamical matter and demonstrate how it allows for an implementation of the toric-code ground state and its topological excitations. This is achieved by introducing separate matter excitations on individual plaquettes, whose motion induce the required plaquette terms. The proposed building block is realized in the second-order coupling regime and is well suited for implementations with superconducting qubits. Furthermore, we propose a pathway to prepare topologically non-trivial initial states during which a large gap on the order of the underlying coupling strength is present. This is verified by both analytical arguments and numerical studies. Moreover, we outline experimental signatures of the ground-state wavefunction and introduce a minimal braiding protocol. Detecting a $\pi$-phase shift between Ramsey fringes in this protocol reveals the anyonic excitations of the toric-code Hamiltonian in a system with only three triangular plaquettes. Our work paves the way for realizing non-Abelian anyons in analog quantum simulators.

Spin and charge excitations in the correlated multiband metal Ca3Ru2O7

We use Ru $L_3$-edge resonant inelastic x-ray scattering (RIXS) to study the full range of excitations in Ca$_3$Ru$_2$O$_7$ from meV-scale magnetic dynamics through to the eV-scale interband transitions. This bilayer $4d$-electron correlated metal expresses a rich phase diagram, displaying long range magnetic order below 56 K followed by a concomitant structural, magnetic and electronic transition at 48 K. In the low temperature phase we observe a magnetic excitation with a bandwidth of $\sim$30 meV and a gap of $\sim$8 meV at the zone center, in excellent agreement with inelastic neutron scattering data. The dispersion can be modeled using a Heisenberg Hamiltonian for a bilayer $\mathrm{S}=1$ system with single ion anisotropy terms. At a higher energy loss, $dd$-type excitations show heavy damping in the presence of itinerant electrons, giving rise to a fluorescence-like signal appearing between the $t_{2g}$ and $e_g$ bands. At the same time, we observe a resonance originating from localized $t_{2g}$ excitations, in analogy to the structurally related Mott-insulator Ca$_2$RuO$_4$. But whereas Ca$_2$RuO$_4$ shows sharp separate spin-orbit excitations and Hund's-rule driven spin-state transitions, here we identify only a single broad asymmetric feature. These results indicate that local intra-ionic interactions underlie the correlated physics in Ca$_3$Ru$_2$O$_7$, even as the excitations become strongly mixed in the presence of itinerant electrons.

Bifurcation analysis of the influence of generator excitation forms on system voltage stability

Based on a typical power system model, this paper simulates the scenario of the increase of active power output of a proximal generator around certain bus node and applies bifurcation theory to study the influence of different excitation forms on system voltage stability after reaching generator excitation saturation. With numerical bifurcation analysis software MATCONT, the simulation analysis results show that the smaller the excitation output upper limit value is, the earlier the bus voltage reaches the Hopf bifurcation with the increase of active power output. In the case of self-shunt excitation, the output of the excitation upper limit value is constrained by the generator terminal voltage. Therefore, the bifurcation point in this case occurs earlier than that in the case of separate excitation.

Switching resonance character within merocyanine stacks and its impact on excited-state dynamics

Summary In this study, the optical properties and excited-state dynamics of the unique self-assembled donor-acceptor (DA) merocyanine dye stacks from dimer up to octamer, prepared via dipole-dipole interactions, are reported in terms of coherent exciton dynamics and formation of an excimer-like state. Our findings are based on the steady-state absorption/emission, time-resolved fluorescence, and transient absorption (anisotropy) measurements, including wavepacket analysis and quantum mechanical calculations. Coherent exciton of torsional motions-restricted dye stacks rapidly localizes into the weakly emissive excimer-like state, by shortening the inter-moiety distance and changing the bond-length alternation pattern. The inner merocyanine moiety, having two neighboring units, has a reversed resonance character (non-polar (N) Z) in the ground state. This difference has led to two conclusions: (1) tetramers and octamers exhibit different features of excimer-like state than the dimer, and (2) octamers exhibit slower localization dynamics due to the enhanced homogeneity (six inner-moieties) compared with tetramers (two inner moieties).

Anomalous Spin-Charge Separation in a Driven Hubbard System.

Spin-charge separation (SCS) is a striking manifestation of strong correlations in low-dimensional quantum systems, whereby a fermion splits into separate spin and charge excitations that travel at different speeds. Here, we demonstrate that periodic driving enables control over SCS in a Hubbard system near half filling. In one dimension, we predict analytically an exotic regime where charge travels slower than spin and can even become "frozen," in agreement with numerical calculations. In two dimensions, the driving slows both charge and spin and leads to complex interferences between single-particle and pair-hopping processes.

Aza-BODIPY Probe-Decorated Mesoporous Black TiO2 Nanoplatform for the Highly Efficient Synergistic Phototherapy

As an important noninvasive tumor treatment method, phototherapy has drawn extensive research interest. However, the requirements of separate excitation wavelengths, high degree of electron-hole recombination, and low reactive oxygen species (ROS) production capability are still the major barriers. This work reports the construction of a novel nanoplatform: design and synthesis of an aza-BODIPY (AB) probe-decorated mesoporous black titanium dioxide (TiO2) (MT) nanoparticles (NPs) for enhanced photodynamic therapy and photothermal therapy under single-wavelength near-infrared (NIR) laser irradiation for the first time. AB probe-decorated MT NPs (abbreviated as MTAB) were synthesized through the Al reduction of mesoporous anatase TiO2 NPs and subsequent adsorption of the AB probe. The mesoporous structure of MT ensured AB loading capacity and avoided the complicated modification and synthesis processes. Heterogeneous MTAB, which possessed staggered energy levels, were assessed for their capability for effective separation of photogenerated electrons and holes for the first time. Upon NIR laser light irradiation, MTAB exhibited sufficient ROS generation, resulting in distinct tumor cell killing and tumor tissue elimination. This unique heterogeneous nanoplatform with staggered energy levels provides a new strategy to enhance ROS generation and improve the therapeutic efficacy.

Design of Hyperthermia Applicator to Heat Multi-Brain Tumors Simultaneously Based on Adaptive Beamforming Technique

Recently, hyperthermia therapy is considered as one of the key treatment principles due to its importance and effectiveness in healing the deep-seated tumors. However, for brain tumors, it is difficult to heat due to high perfusion and thermal conductivity of the head. Therefore, in this research, the technique of non-invasive heat focalization in multiple tumors, simultaneously, without affecting healthy tissue based on adaptive beamforming was investigated and presented. It is done by controlling the feeding of the antenna array surrounding the brain using a modified hybrid version of gravitational search algorithm and particle swarm optimization (MGSA-PSO). An antenna system in the form of a head helmet was designed and evaluated with 48 antenna elements each of them has a separate excitation that controls the field intensity and beamforming direction towards the tumors. Many scenarios considering a single tumor in different positions with different volumes or multiple tumors are studied to evaluate the performance of the applicator. The helmet was tested on the challenging scenario of a very mature and dense brain with realistic thermal and dielectric properties. The results confirmed the ability of the helmet technology and the proposed antenna system to use a microwave power of 65 W to lift the neoplasm temperature to over 42 °C while keeping healthy tissue safe at 37 degrees with none hot spots. Furthermore, the results showed the capability of the proposed model to treat multiple tumors simultaneously.

Pd/ZnO/Ni photoelectrochemical ethanol sensor

In this paper, by using hexagonal prism nanometer zinc oxide absorbing UV-light photoinduced charge separation excitation electrode. The separation of excitation source and detection source reduces the interference of background noise and effectively improves the sensitivity of the electrode. At the same time, the surface of the electrode was modified by metal particles to increase the surface area of the electrode, improve the adsorption capacity of the electrode to ethanol, and inhibit electron hole recombination improves the sensitivity of the electrode. We have engineered a kind of Pd/ZnO/Ni photochemical ethanol electrode, which by hydrothermal method using nickel foam as the base to grow Hexagonal prism nanometer zinc oxide and by electrochemical deposition on the surface of ZnO/Ni electrode were deposited palladium particles. The electrode has been verified by the experiment can detect 0.02 μM the change of ethanol. The electrode surface morphology of the electrode was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Energy dispersive spectrum (EDS), and the performance of the electrode was tested by Cyclic Voltammetry (CV) and Chronoamperometry (CA). The test results showed that the electrode had favorable sensitivity and linear relationship to ethanol. Compared with traditional electrochemical sensors, the sensitivity of Pd/ZnO/Ni has been improved greatly. It provides an effective solution to improve the detection accuracy of ethanol sensor in industrial and medicine and fruit and vegetable storage.

Plasmon excitations in chemically heterogeneous nanoarrays

The capability of collective excitations, such as localized surface plasmon resonances, to produce a versatile spectrum of optical phenomena is governed by the interactions within the collective and single-particle responses in the finite system. In many practical instances, plasmonic metallic nanoparticles and arrays are either topologically or chemically heterogeneous, which affects both the constituent transitions and their interactions. Here, the formation of collective excitations in weakly Cu- and Pd-doped Au nanoarrays is described using time-dependent density functional theory. The additional impurity-induced modes in the optical response can be thought to result from intricate interactions between separated excitations or transitions. We investigate the heterogeneity at the impurity level, the symmetry aspects related to the impurity position, and the influence of the impurity position on the confinement phenomena. The chemically rich and symmetry-dependent quantum mechanical effects are analyzed with transition contribution maps demonstrating the possibility to develop nanostructures with more controlled collective properties.