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- periodic paperclip-shaped structure
- antenna array
- mutual coupling reduction
- Bessel Function
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- Fusion temperature and Elongation speed
- Electronic Science and Technology
- Physics
- UIN Suska Riau
- Xi'an University of the Science and Technology
- University of Riau
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Improvement of the Beam-Wave Interaction Efficiency Based on the Coupling-Slot Configuration in an Extended Interaction Oscillator
摘要： A method aimed at improving the beam-wave interaction efficiency by changing the coupling slot configuration has been proposed in the study of extended interaction oscillators (EIOs). The dispersion characteristics, coupling coefficient and interaction impedance of the high-frequency structure based on different types of coupling slots have been investigated. Four types of coupled cavity structures with different layouts of the coupling slots have been compared to improve the beam-wave interaction efficiency, so as to analyze the beam-wave interaction and practical applications. In order to determine the improvement of the coupling slot to a coupled cavity circuit in an EIO, we designed four nine-gap EIOs based on the coupled cavity structure with different coupling slot configurations. With different operating frequencies and voltages takes into consideration, beam voltages from 27 to 33 kV have been simulated to achieve the best beam-wave interaction efficiency so that the EIOs are able to work in the 2π mode. The influence of the Rb and the ds on the output power is also taken into consideration. The Rb is the radius of the electron beam, and the ds is the width of the coupling slot. The simulation results indicate that a single-slot-type EIO has the best beam-wave interaction efficiency. Its maximum output power is 2.8 kW and the efficiency is 18% when the operating voltage is 31 kV and electric current is 0.5 A. The output powers of these four EIOs that were designed for comparison are not less than 1.7 kW. The improved coupling-slot configurations enables the extended interaction oscillator to meet the different engineering requirements better.
关键词： Output power,Coupling slot configuration,Extended interaction oscillator,Beam-wave interaction efficiency
更新于2025-09-23 15:22:29
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Sequential activation of methane by Ir+: An IRMPD and theoretical investigation
摘要： The sequential activation of up to 4 CH4 molecules by Ir+ is investigated through a gas-phase infrared multiple photon dissociation (IRMPD) experiment and theoretical calculations. A molecular beam apparatus was used to generate Ir+ by laser ablation and expose it to controlled amounts of CH4. Product ions were irradiated with IR light from a free electron laser over the 500–1800 cm?1 spectral range and photodissociation was monitored using a time-of-flight mass spectrometer. Experimental spectra were obtained for five distinct species: [Ir,3C,8 H]+, [Ir,3C,10 H]+, [Ir,4C,10 H]+, [Ir,4C,12 H]+, and [Ir,O,3C,12 H]+. To identify these species, B3LYP/def2-TZVPPD geometry optimizations were performed on a variety of possible structures, with computed IR spectra compared to the experimental IRMPD spectra. This has led to the following assignments: [Ir,3C,8 H]+ = IrCH2(CH3)2+, [Ir,3C,10 H]+ = HIr(CH3)3+, [Ir,4C,10 H]+ = Ir(CH3)2(C2H4)+, [Ir,4C,12 H]+ = a mixture of HIr(CH3)(C2H4)+(CH4), HIr(CH3)2(C2H5)+, Ir(CH3)4+, and (H2)Ir(CH3)2(C2H4)+, and [Ir,O,3C,12 H]+ = (H2O)HIr(CH3)3+. Notably, evidence for C C coupling is observed upon reaction with a fourth methane. Mechanisms for the formation of the observed products were also explored computationally by examining the reaction coordinate pathways for the reactions of methane with HIrCH+, IrCH2+, Ir(CH3)2+, HIrCH2(CH3)+, HIr(CH3)3+, and IrCH2(CH3)2+.
关键词： Iridium,Carbon-carbon coupling,Methane activation,Dehydrogenation,Infrared multiple photon dissociation,Reaction coordinate pathway
更新于2025-09-23 15:22:29
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Sm-mediated dielectric characteristics and tunable magneto-electric coefficient of 0.5Bi1-xSmxFe0.95Mn0.05O3-0.5PbTiO3 composites
摘要： Magneto-electric multiferroic composites have gained a lot of interest these days mainly due to extensive potential of coupling between ferroelectric and magnetic orders. In this work, we present a series of 0.5Bi1-xSmxFe0.95Mn0.05O3 ? 0.5PbTiO3 (x = 0.00, 0.03, 0.06, 0.09, 0.12 and 0.15) composites, prepared by sol-gel auto-combustion and solid state reaction method to explore the tunability of magneto-electric coefficient. X-ray diffraction confirmed the rhombohedraly distorted cubic perovskite and tetragonal structures of BiFeO3 and PbTiO3, respectively. Ferroelectric loops showed that leakage current can be tuned and reduced by Sm-doping. Magnetic analysis showed switching of antiferromagnetic behaviour into weak ferromagnetic behaviour. Saturation and remanent magnetization were also calculated exhibiting an increasing trend with increasing Sm contents. Synthesized composites showed the non-linear frequency dependent dielectric response which was explained on the basis of Maxwell Wagner theory. Time varying conductivity was probed on the basis of polaron mechanism. The optimized composite reveal an enhanced magneto-electric coupling as compared to that of pure BiFeO3 which makes them feasible for the fabrication of multifunctional devices.
关键词： Magneto-electric coupling,Composites,Multiferroics
更新于2025-09-23 15:22:29
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Two dimensional topological insulators in bilayer BiB
摘要： With the help of ?rst-principles calculations, we propose a new type of two dimensional (2D) topological insulator BiB with bilayer hexagonal lattice. Its dynamic stability was con?rmed by the phonon spectrum. When spin-orbit coupling (SOC) e?ect is not considered, the low energy electronic states around the Fermi level show metallic characteristics. However, the SOC will induce a global band gap and turn this 2D material into topological insulators with nontrivial edge states. Surprisingly, two mechanisms, including crystal ?eld and strong SOC, induce two band inversions and manipulate the low energy electronic states simultaneously. The BiB provides a fertile platform for studying the interactions between the two di?erent mechanisms in the same topological insulator. Moreover, the sizable global nontrivial band gap indicates its high working temperature.
关键词： Topological insulator,Edge states,Z2,Spin-orbit coupling (SOC)
更新于2025-09-23 15:22:29
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Charged polariton luminescence from an organic semiconductor microcavity
摘要： Strong coupling light to polaron optical transitions in an organic semiconductor microcavity leads to an unusual class of polariton that possesses a net charge. This species may offer a range of technologically-useful optoelectronic properties but has thus far only been observed in passive reflectivity measurements. Here, we report room-temperature photoluminescence from both upper and lower branch polaron polariton states that originate from hole excitations in a p-doped 4,4’-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) microcavity. Our observations under non-resonant excitation are in good agreement with classical dipole emission modeling, which suggests that polariton states in this system are populated radiatively via fluorescence from the polaron excited state reservoir. These results constitute one of the first observations of polaron luminescence from an organic semiconductor thin film and are an important prerequisite for realizing a charged polariton condensate.
关键词： strong coupling,Polaron,fluorescence,cation
更新于2025-09-23 15:22:29
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Mimicking a hybrid-optomechanical system using an intrinsic quadratic coupling in conventional optomechanical system
摘要： We consider an optical and mechanical mode interacting through both linear and quadratic dispersive couplings in a general cavity-optomechanical set-up. The parity and strength of an intrinsic quadratic optomechanical coupling (QOC) provides an opportunity to control the optomechanical (OM) interaction. We quantify this interaction by studying normal-mode splitting (NMS) as a function of the QOC's strength. The proposed scheme exhibits NMS features equivalent to a hybrid-OM system containing either an optical parametric amplifier or a Kerr medium. Such a system in reality could offer an alternative platform for devising state-of-art quantum devices with requiring no extra degrees-of-freedom as in hybrid-OM systems.
关键词： Cavity-optomechanics,quadratic optomechanical coupling,normal-mode splitting,resolved side-band regime
更新于2025-09-23 15:22:29
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All Passive Realization of Lossy Coupling Matrices Using Resistive Decomposition Technique
摘要： A complex coupling matrix has been extensively used in lossy filters and negative group delay devices. For the realization, conventional technique decomposes the complex coupling matrix into lossy resonators and complex inverters. Since the complex inverter does not follow the passivity in some cases, the resultant realization may be globally passive but locally active. This paper proposes a new decomposition technique to ensure the passivity everywhere. It decomposes the complex coupling matrix into a resistive connection matrix and a conventional real coupling matrix, which are both passively realizable. This technique provides a passive realization of the complex coupling matrix. Furthermore, a loss equalization technique is also proposed, to further achieve a uniform quality factor (Q) distribution among all the lossy resonators. Several illustrative examples and an experimental validation are finally provided.
关键词： Lossy filter,resistive connection,quality factor,decomposition,complex coupling matrix,complex inverter
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Low-Loss, High-Frequency and Large-Coupling SH SAW Resonators Based on SiN/LiNbO<inf>3</inf>/Si
摘要： Low-loss, high-frequency and large-coupling-coefficient SAW resonators based on SiN/LN/Si are demonstrated in this study. By bonding the high-velocity Si substrate to the sub-wavelength-thick LN layer, the shear-horizontal mode SAW resonator no longer couples with the bulk modes in substrate and the leaky component is effectively eliminated. As the propagation loss is no longer the main concern for the cut angle selection, the ultra-large cut angle can be used to achieve high coupling coefficient (κ2). By carefully designing the SiN/LN/Si structure, the high-frequency and large-κ2 SAW resonators with low loss are achieved. The fabricated SAW resonators show great potential for current and next generation front ends.
关键词： SiN/LN/Si,large coupling coefficient,high frequency,low loss,SAW resonators
更新于2025-09-23 15:22:29
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An Orbital Angular Momentum-Based Array for In-Band Full-Duplex Communications
摘要： A uniform circular array (UCA) with dual orbital angular momentum (OAM) modes is proposed for in-band full-duplex applications. The proposed scheme includes two concentric ring subarrays for transmitting and receiving, respectively, where all elements are operated under the same linear polarization. To suppress the self-interference resulting from the mutual coupling, an OAM mode-selection method related to the proposed configuration is discussed. Results indicate that good isolation performance between the transmitter and receiver can be achieved by using the proposed scheme. To validate the performance, a demonstrator with OAM modes of -1 and -2 at Ku-band is developed, fabricated, and measured. Measurements show a relative bandwidth of 21.3% from 13.5 to 16.7 GHz, referring to a 40-dB suppression level, is achieved and the desired radiations are found.
关键词： self-interference suppression,uniform circular array,full-duplex,mutual coupling,Orbital angular momentum
更新于2025-09-23 15:22:29
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Triple Gate Polycrystalline-Silicon-Based Ion-Sensitive Field-Effect Transistor for High-performance Aqueous Chemical Application
摘要： In this study, we developed a polycrystalline-silicon (poly-Si) thin-film transistor (TFT)-based, high-performance ion-sensitive field-effect transistor (ISFET) pH sensor that far surpasses the sensitivity of dual-gate pH sensors. A Triple gate structure on the same plane as the channel of the ISFET has been proposed to enhance the pH sensitivity. In a poly-Si TFT-based ISFET, a Triple gate is more advantageous than a bottom-gate for increasing capacitive coupling with the top-gate. As a result, the pH sensitivity by Triple gate (TG) mode detection using the Triple gate is much greater than single-gate (SG) mode detection using the top-gate, or dual-gate (DG) mode detection using the bottom-gate. The sensitivity of the TG mode greatly increased compared with the sensitivity of the conventional SG mode or DG mode. The measured pH sensitivity was 57.75 ± 0.77 mV/pH in the SG mode, 467.08 ± 9.92 mV/pH in the DG mode. In particular, the TG mode gives a maximum sensitivity of 1283.56 ± 45.54 mV/pH for a sensing membranes having a theoretical Nernstian pH response (59.15 mV/pH at 25 °C). Furthermore, we measured the hysteresis and drift characteristics, and found that the TG mode has improved non-ideal behavior compared to the SG and DG modes. Therefore, the poly-Si TFT-based TG ISFET pH sensor has the potential to become a promising biosensor application platform, with excellent sensitivity and stability.
关键词： ion-sensitive field effect transistor,Triple gate,capacitive coupling effect
更新于2025-09-23 15:22:29