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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • MPPT
  • photovoltaic (PV) power systems
  • Induction motor
  • three-phase four switch inverter
  • two-inductor boost converter
应用领域
  • Electrical Engineering and Automation
机构单位
  • Sree Buddha College of Engineering
149 条数据
?? 中文（中国） ▾

  • Laser-triggered gas switch with subnanosecond jitter and breakdown delay tunable over a??0.1a??10 ns governed by the spark gap ignition angle

    摘要： We created a practical air-filled switch triggered by a ～ 109 W picosecond laser beam with a slightly variable breakdown delay and low jitter. The switch relies on the spark gap with a coaxial geometry, which is ignited by a focused laser beam directed at a certain angle to the gap axis. The switch is integrated with a high-voltage cable generator operating at a constant negative voltage of up to 50 kV. We demonstrate that, by just varying the ignition angle of the spark gap, one can achieve variable breakdown delay tunable within ～ 0.1–10 ns with <～ 1 ns jitter. Empirical dependences of switching characteristics of the developed device on the ignition angle are obtained. We demonstrate that, combined with variation of the ignition beam energy and charging voltage, variation of the spark gap ignition angle provides superior control over the gap switching characteristics without complicating the switch design. The proposed approach to driving the switching characteristics appears highly promising for designing compact Laser-Triggered Gas Switches with variable temporal characteristics and achieving precise synchronization between high-voltage and measuring equipment.

    关键词： atmospheric discharge,high current electronics,spark switch,laser triggering

    更新于2025-09-23 15:19:57

  • Reversible and tunable photochemical switch based on plasmonic structure

    摘要： For the first time, pyranine (8-hydroxypyrene-1,3,6-trisulfonate, HPTS) is studied for realizing active plasmonic control, which is attracted considerable attention owing to its unique photophysical and photochemical properties. We have used this photoacid (HPTS) as an active surrounding medium that can be optically controlled and used for modulating plasmon resonances. In this paper, the fabrication of 2D-plasmonic grating coated by thin film of HPTS exposed to UV irradiation is reported. By switching the UV light on and off, the HPTS thin film maintains an excited-state proton transfer (ESPT) process followed by green fluorescence resulting in a plasmonic redshift caused by the variation of the refractive index. Furthermore, this photochemical active medium has also played another important role in plasmonic sensing, in which the emission-based response of HPTS thin film in 2D-plasmonic grating to water vapor upon photoexcitation is demonstrated, for both s and p polarizations. This tunable, flexible and reversible light-driven system will enhance the development of active plasmonic structures and will have a great influence on many fields such as, biochemical optical sensors and all-optical plasmonic circuits.

    关键词： photochemical switch,UV irradiation,plasmonic sensing,plasmonic structure,HPTS

    更新于2025-09-23 15:19:57

  • Laser-diode dual-end-pumped electro-optic Q-switched slab Tm:YAP laser

    摘要： A high-repetition-rate and double-end pumped electro-optic Q-switched Tm:YAlO3 (Tm:YAP) laser is reported. The Tm:YAP slab crystal cut by c-axis is used as the laser gain medium, and the RbTiOPO4(RTP) crystal is selected as the electro-optic Q-switched crystal. Choosing volume Bragg gratings (VBG) as the input mirror to narrow the output line width. When the pump power is 79.2 W, at a repetition rate of 10 kHz, maximum average-output-power of 21.96 W is achieved, with the pulse width of 20.64 ns and output energy of 2.20 mJ. The output peak power is 107.3 kW and the slope efficiency is 29.2%. The center wavelength is 1937.87 nm and the line width is 0.73 nm. The beam quality in the x direction is 1.48, and in the y direction is 1.50.

    关键词： Electro-optic Q-switch,High repetition rate,Tm:YAP laser,RTP

    更新于2025-09-23 15:19:57

  • Optimal configuration of hybrid-energy microgrid considering the correlation and randomness of the wind power and photovoltaic power

    摘要： Despite rapid advances in the study of brain–computer interfaces (BCIs) in recent decades, two fundamental challenges, namely, improvement of target detection performance and multidimensional control, continue to be major barriers for further development and applications. In this paper, we review the recent progress in multimodal BCIs (also called hybrid BCIs), which may provide potential solutions for addressing these challenges. In particular, improved target detection can be achieved by developing multimodal BCIs that utilize multiple brain patterns, multimodal signals, or multisensory stimuli. Furthermore, multidimensional object control can be accomplished by generating multiple control signals from different brain patterns or signal modalities. Here, we highlight several representative multimodal BCI systems by analyzing their paradigm designs, detection/control methods, and experimental results. To demonstrate their practicality, we report several initial clinical applications of these multimodal BCI systems, including awareness evaluation/detection in patients with disorder of consciousness (DOC). As an evolving research area, the study of multimodal BCIs is increasingly requiring more synergetic efforts from multiple disciplines for the exploration of the underlying brain mechanisms, the design of new effective paradigms and means of neurofeedback, and the expansion of the clinical applications of these systems.

    关键词： brain switch,multimodal brain–computer interface (BCI),awareness evaluation,Audiovisual BCI,cursor control

    更新于2025-09-23 15:19:57

  • Four-channel THz wave routing switch based on magneto photonic crystals

    摘要： A four-channel routing switch based on a square lattice 2-D silicon photonic crystal with four point defects and five line defects is proposed. In this scheme, the properties that magnetic permeability of the ferrite material changing with external magnetic field and the coupling characteristics between line defect and point defect are used. The proposed device is theoretically analyzed and numerically investigated by using plane wave method (PWM) and finite-difference time-domain (FDTD). The results show that the four-channel routing switch can be realized by applying different intensity of magnetic fields. The extinction ratios of the four channels are all more than 13dB, the transmittance rates are higher than 93%, the insertion losses are lower than 0.288dB, and steady times are less than 50 ps. The proposed THz routing switch has potential applications in terahertz wave integrated circuit fields in the future.

    关键词： THz wave；routing switch；magneto photonic crystal

    更新于2025-09-23 15:19:57

  • Mechanically Induced Switching of Molecular Layers

    摘要： Within the field of switchable surfaces, azobenzenes are an extensively studied group of molecules, known for reversibly changing conformation upon illumination with light of different wavelengths. Relying on the ability of the molecules to change properties and structure as a response to external stimuli, they have been incorporated in various devices, such as molecular switches and motors. In contrast to the well-documented switching by light irradiation, we report the discovery of mechanically triggered switching of self-assembled azobenzene monolayers, resulting in changes of surface wettability, adhesion, and friction. This mechanically induced cis?trans isomerization is triggered either locally and selectively by AFM or macroscopically by particle impact. The process is optically reversible, enabling consecutive switching cycles. Collective switching behavior was also observed, propagating from the original point of impact in a domino-like manner. Finally, local force application facilitated nondestructive and erasable nanopatterning, the cis?trans nanolithography.

    关键词： Molecular switch,self-assembled monolayers,mechanical switching,nanolithography,azobenzene

    更新于2025-09-19 17:15:36

  • A scheme for the development of a trinary logic unit (TLU) using polarization-based optical switches

    摘要： Frequency-encoded optical processors based on multivalued logic (MVL) will play a significant role in future all-optical networks. In this work, basic optical logic gates are designed using a modified trinary system, exploiting the switching action of semiconductor optical amplifiers (SOAs) based on the principle of the nonlinear rotation of the polarization of a probe beam in the presence of a pump beam. A control unit capable of performing OR, AND, and XOR logic operations depending on the frequency of the control signal is then developed. Finally, a trinary logic unit is designed to execute 27 different logic operations. The feasibility of these proposals is confirmed by simulation results. In this approach, each trinary bit, i.e., 'trit,' is represented by a unique frequency, which in turn helps to address the noise margin problem that arises in intensity-encoded MVL systems. This scheme can therefore play an important role in errorless optical computing and processing.

    关键词： Modified trinary number,Multivalued logic,Semiconductor optical amplifier,Trinary logic unit,Polarization switch

    更新于2025-09-19 17:15:36

  • Novel multi-responsive fluorescence switch for Hg2+ and UV/vis lights based on diarylethene-rhodamine derivative

    摘要： A new multi-responsive fluorescent switch DTE-Pip-Rho 1O has been designed and synthesized in this study. For this molecule, the reactive site of spirolactam ring is far away from the diarylethene unit through the intramolecular piperazine. It exhibited high selectivity and sensitivity to Hg2+ in addition to obvious color change (colorless-pink) and fluorescence “off-on” (dark-orange) during this process. It is believed that the color change is due to Hg2+-assisted hydrolysis of rhodamine hydrazide. Therefore, the new molecule can be used as colorimetric and fluorescent chemosensor for Hg2+ with high selectivity. The detection limits of absorbance and fluorescence for Hg2+ were calculated to be 1.15 μM and 1.16 μM, respectively. The resulting DTE-Pip-Rho 1O-Hg2+ could also function as a reversible fluorescence photo-switch in response to UV/vis light owing to FRET mechanism. Moreover, it has been demonstrated that the photo-switchable system displayed excellent fatigue resistance and remarkable anti-photobleaching capability.

    关键词： Multi-responsive,Fluorescent switch,Diarylethene,FRET mechanism,Sensor,Rhodamine

    更新于2025-09-19 17:15:36

  • Rhodamine-naphthalimide demonstrated a distinct aggregation-induced emission mechanism: elimination of dark-states <i>via</i> dimer interactions (EDDI)

    摘要： Rhodamine B-naphthalimide (RhB-Naph) demonstrated a distinct aggregation-induced emission (AIE) mechanism, different from the restriction of intramolecular rotations or vibrations as in traditional AIE molecules. The monomers of RhB-Naph were non-emissive, due to the presence of a dark S1 state. Upon molecular aggregation, intermolecular interactions significantly altered the electronic properties of RhB-Naph, leading to the formation of a bright S1 state and endowing RhB-Naph with notable AIE properties. Besides, we demonstrated that RhB-Naph enabled the development of a solid-state three-color fluorescent switch upon multi-external stimuli.

    关键词： fluorescent switch,dark state,dimer interactions,rhodamine-naphthalimide,aggregation-induced emission

    更新于2025-09-19 17:15:36

  • Experimental demonstration of an ultra-low latency control plane for optical packet switching in data center networks

    摘要： Optical interconnection networks have the potential to reduce latency and power consumption while increasing the bisection bandwidth of data center networks compared to electrical network architectures. Optical circuit-switched networking has been proposed but it is reconfigurable in milliseconds. Although switches operating on nanosecond timescales have been demonstrated, centrally scheduling such switching architectures is considered to be of high complexity, incurring significant delay penalties on the total switching latency. In this paper we present a high-speed control plane design based on a central switch scheduler for nanosecond optical switching which significantly reduces the end-to-end latency in the network compared to using the best electronic switches. We discuss the implementation of our control plane on field-programmable gate array (FPGA) boards and quantify its delay components. We focus on the output-port allocation circuit design which limits the scheduling delay and the end-to-end latency. Using our FPGA-implemented control plane, for a 32 × 32 switch, we experimentally demonstrate rack-scale optical packet switching with a minimum end-to-end head-to-tail latency of 71.0 ns, outperforming current state-of-the-art electronic switches. The effect of asynchronous control plane operation on the switch performance is evaluated experimentally. Finally, a new parallel allocation circuit design is presented decreasing the scheduling delay by 42.7% and the minimum end-to-end latency to 54.6 ns. More importantly, it enables scaling to a switch double the size (64 × 64) with a minimum end-to-end latency less than 71.0 ns. In a developed cycle-accurate network emulator we demonstrate nanosecond switching up to 60% of port capacity and average end-to-end latency less than 10 μs at full capacity while maintaining zero packet loss across all traffic loads.

    关键词： Optical interconnects,Optical crossbar switch scheduling,Physical-layer control plane design,Optical packet switching

    更新于2025-09-19 17:15:36