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- 实验方案
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Improved Charge Pump Design and $Ex\ Vivo$ Experimental Validation of CMOS 256-Pixel Photovoltaic-Powered Subretinal Prosthetic Chip
摘要： An improved design of a 256-pixel photovoltaic-powered implantable chip for subretinal prostheses is presented. In the proposed subretinal chip, a high-efficiency fully-integrated 4× charge pump is designed and integrated with on-chip photovoltaic (PV) cells and a 256-pixel array with active pixel sensors (APS) for image light sensing, biphasic constant current stimulators, and electrodes. Thus the PV voltage generated by infrared (IR) light can be boosted to above 1V so that the charge injection is increased. The proposed chip adopts the 32-phase divisional power supply scheme (DPSS) to reduce the required supply current and thus the required area of the PV cells. The proposed chip is designed and fabricated in 180-nm CMOS technology and post-processed with image sensor biocompatible IrOx electrodes and silicone packaging. From the electrical measurement results, the measured stimulation frequency is 28.3 Hz under the equivalent electrode impedance load. The measured maximum output stimulation current is 7.1 μA and the amount of injected charges per pixel is 7.36 nC under image light intensity of 3200 lux and IR light intensity of 100 mW/cm2. The function of the proposed chip has been further validated successfully with the ex vivo experimental results by recording the electrophysiological responses of retinal ganglion cells (RGCs) of retinas from retinal degeneration (rd1) mice with a multi-electrode array (MEA). The measured average threshold injected charge is about 3.97 nC which is consistent with that obtained from the patch clamp recording on retinas from wild type (C57BL/6) mice with a single electrode pair.
关键词： biocompatible package,divisional power supply scheme,multi-electrode array,charge pump,photovoltaic cell
更新于2025-09-11 14:15:04
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Design scheme for fast charging station for electric vehicles with distributed photovoltaic power generation
摘要： The demand for fast charging is increasing owing to the rapid expansion of the market for electric vehicles. In addition, the power generation technology for distributed photovoltaic has matured. This paper presents a design scheme for a fast charging station for electric vehicles equipped with distributed photovoltaic power generation system taking the area with certain conditions in Beijing as an example construction site. The technical indexes and equipment lectotype covering the general framework and subsystems of the charging station are determined by analyzing the charging service demand of fast charging stations. In this study, the layout of the station is developed and the operation benefits of the station is analyzed. The design scheme realizes the design objective of “rationalization, modularization and intelligentization” of the fast charging station and can be used as reference for the construction of a fast charging network in urban area.
关键词： Design scheme,Electric vehicle,Charging demand,Distributed photovoltaic,Fast charging station
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing ADVANCES IN BASIC SCIENCE (ICABS 2019) - Bahal, India (7–9 February 2019)] ADVANCES IN BASIC SCIENCE (ICABS 2019) - Profit analysis of a uni-directional and non revertible 1+1 protection switching scheme in optical communication process
摘要： The present paper examines availability and profit analysis of a system comprising four optical lines out of which two are operative (working paths) and the other two are hot-standby (protection paths). Each working line has its own hot standby. On the failure of the working path, signal is received from its own protection path and the failed unit is gone under repair immediately by a repairman. If a working path and its corresponding protection path both get failed then system is said to be failed. The system is analyzed by making use of regenerative point technique. Various measures of system effectiveness as well as expression for finding the profit have been obtained.
关键词： 1+1 Protection Scheme,availability,reliability,profit analysis
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - The Photonic Guitar Pickup: A High-Sensitivity, High-Bandwidth Fiber Strain Sensor
摘要： The photonic guitar pickup: a high-sensitivity, high-bandwidth fiber strain sensor. Fiber-strain sensors have found numerous applications from structural health monitoring for vibrations, to pressure and temperature sensing. Many of these sensors exploit the strain-sensitivity of the reflection wavelength of fiber-bragg gratings, (cid:83)-shifted gratings or other waveguide devices. The strain is typically inferred from a change of reflected or transmitted light intensity. Light intensity measurements are not very robust and have an inherently limited accuracy. We propose that a frequency-based strain measurements using fiber Fabry-Perot (FFP) cavities provide not only superior sensitivity but also retain a very high measurement bandwidth. Here, we present a fiber optic vibration sensor based on an FFP cavity, which consists of a matched pair of 23 dB fiber Bragg gratings coupled to a custom-built signal processing circuit. The wavelength of a laser diode is locked to one of the many cavity resonances using the Pound–Drever–Hall scheme. We demonstrate that such a strain sensor has an ultrawide dynamic sensing range, from less than 1 Hz to clinical ultrasound frequencies near 6 MHz. Its linear sensitivity range extends from below 1 n(cid:72) to 2 (cid:80)(cid:72), and its dynamic response limit is as high as 12 m(cid:72)/s. To demonstrate the high fidelity of the strain measurements we attached the FFP cavity sensor to the top plate of an acoustic guitar and recorded several melodies. As expected the sensor system was largely immune to noise arising from optical intensity fluctuations. We made distortion-free audio recordings of musical pieces from infrasound (~8 Hz) to 30 kHz with a 50 dB dynamic range in acoustic power. The remaining noise in our measurements arises from electronic sources and not optical sources, giving hope that future developments may be able to further increase the dynamic range of the measurements, if needed. In separate experiments the same sensor was affixed to the rim of a wineglass and to the side of a steel cantilever to monitor the (photo-)acoustic response of these mechanical resonators to periodic photo-excitation. We found, for example, that the limit of detection for orthophosphate through the photoacoustic excitation of the respective molybdenum-blue complex was below 2 ppm. Finally, the sensor was embedded in tissue phantoms to validate that it accurately responds to low frequencies (heart beat) and high frequencies (ultrasound pulse). In its most recent version the laser driver and the PDH circuit are addressed through a Raspberry-Pi microcontroller, making the sensor system very compact and relatively inexpensive. We propose that sensor systems based on PDH-interrogated FFP-sensor heads are robust and versatile for a large variety of monitoring applications.
关键词： Fabry-Perot cavity,vibration sensor,dynamic range,Pound–Drever–Hall scheme,fiber strain sensor
更新于2025-09-11 14:15:04
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[IEEE 2019 28th Wireless and Optical Communications Conference (WOCC) - Beijing, China (2019.5.9-2019.5.10)] 2019 28th Wireless and Optical Communications Conference (WOCC) - Secrecy Performance Analysis for Hybrid Satellite Terrestrial Relay Networks with Multiple Eavesdroppers
摘要： In this paper, we investigate the secrecy performance of hybrid satellite terrestrial relay networks (HSTRN) with multiple eavesdroppers, particularly, all nodes in the networks are equipped with single antenna, respectively. In addition, we propose two selection schemes in the networks, namely, Case I, which means choosing the larger secrecy capacity among Satellite-Relay and Relay-Destination ; Case II, which is choosing the lower secrecy capacity among Satellite-Relay and Relay-Destination. Furthermore, we derive the closed-form expressions for the secrecy outage probability (SOP) of the HSTRN based on the proposed two selection schemes, which provide a fast means to evaluate the impact of system parameters and selection schemes on the secrecy system performance. In order to study the impact of system parameters and selection schemes at high SNRs, we obtain the asymptotic expressions of the SOP of the HSTRN. Finally, in order to verify the accuracy of the analysis described in this paper, simulation results are given.
关键词： joint eavesdropping scheme,secrecy outage probability (SOP),Hybrid Satellite Terrestrial Relay Networks (HSTRN)
更新于2025-09-11 14:15:04
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Theoretical study on the low-lying electronic excited states and laser cooling feasibility of AuH molecule
摘要： To evaluate characteristics of the low-lying electronic states and the feasibility of the laser cooling of the AuH molecule, we investigate the potential energy curves (PECs), the vibrational and rotational characteristics of the ground and low-lying excited electronic states based on ab initio calculations. The PECs of the X1Σ+, A1Σ+, B1Σ+, a3Σ+, b3Σ+, e3Σ+, C1П, D1П, c3П and d3П states and the transition dipole moments among these states are calculated with the multi-reference configuration interaction method with Davidson correction and all-electron basis sets. Based on the obtained PECs, the Schr?dinger equations of nuclear movement are solved to obtain the rotational and vibrational energy levels of the electronic states. The spectroscopic parameters are obtained by fitting the obtained rotational and vibrational levels with Dunham series expansion. The matrices of the Franck-Condon factors (FCFs) dependent on the vibrational quantum numbers are obtained. The feasibility of laser cooling is explored. The FCF of the D1П (v′ = 0) ? X1Σ+ (v″ = 0) transition is 0.9862, which implies that the AuH molecule is feasible but not the much better ones for laser cooling and more pumping lasers are needed. The optical laser cooling scheme is suggested and the Einstein coefficient and the recoil temperature are calculated to evaluate the effect of the cooling scheme.
关键词： Franck-Condon factor,recoil temperature,laser cooling scheme,transition dipole moment,low-lying excited states
更新于2025-09-11 14:15:04
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<i>In situ</i> fabrication of a direct <i>Z</i> -scheme photocatalyst by immobilizing CdS quantum dots in the channels of graphene-hybridized and supported mesoporous titanium nanocrystals for high photocatalytic performance under visible light
摘要： We report the considerable advantages of direct Z-scheme photocatalysts by immobilizing high-quality CdS quantum dots (QDs) in the channels of graphene-hybridized and supported mesoporous titania (GMT) nanocrystals (CdS@GMT/GR) under facile hydrothermal conditions. The photocatalysts have been characterized by XRD, PL, XPS, SEM, DRS, TEM, EIS, and N2 adsorption. CdS QDs primarily serve as photosensitizers with a unique pore-embedded structure for the e?ective utilization of the light source. This direct Z-scheme CdS@GMT/GR exhibits higher photocatalytic activity than CdS/GR, GMT/GR, or CdS@MT. In addition, the rate constant of CdS@GMT/GR-2 is approximately twice the sum of those of CdS@MT and GMT/GR, because GR played the role of hole-transporting and collection layer as well as the hybridization level formation in terms of hybridizing MT and serving as a support. Therefore, the GR content tunes the energy band, a?ects the surface area, and controls the interfacial hole transfer and collection rate of the direct Z-scheme system. Furthermore, CdS@GMT/GR retains its high performance in repeated photocatalytic processes. This can be attributed to the fact that GR prevents QDs from photocorrosion by means of the hole-transporting and collection e?ect. A possible reaction mechanism is proposed. This work provides a promising strategy for the construction of highly e?cient visible-light-driven photocatalysts to reduce the growing menace of environmental pollution.
关键词： environmental pollution,visible-light-driven photocatalysts,graphene-hybridized mesoporous titania,direct Z-scheme photocatalysts,CdS quantum dots
更新于2025-09-11 14:15:04
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Control and Optimization of Residential Photovoltaic Power Generation System With High Efficiency Isolated Bidirectional DC–DC Converter
摘要： Currently, residential photovoltaic power generation system is increasingly used worldwide. In this paper, an optimized structure of residential photovoltaic (PV) power generation system with 1500V DC bus is proposed. It includes PV panels, a three-level boost converter, a high efficiency isolated bidirectional DC-DC converter, battery and three-phase five-level DC-AC converter that can work under islanding mode or grid-connected mode. The higher DC bus voltage greatly reduces line loss and improves efficiency of the system. An energy management scheme used for the system is proposed in this paper to guarantee the stability of the system and to increase its economic benefits. Besides, the optimized method for the structure of the bidirectional dc-dc converter is proposed. This structure can achieve higher DC voltage gain and higher efficiency. Furthermore, for low voltage battery application in the residential system, LLC and CLLC under DC transformer (DCX) mode are evaluated and the LLC is selected as the isolated bidirectional DC-DC converter. The optimized designed method of bidirectional LLC is proposed. Finally, experiments are carried out to verify the performance of the optimized converters and the system.
关键词： high efficiency,Energy management scheme,isolated bidirectional DC-DC converter,residential photovoltaic power generation system,LLC converter
更新于2025-09-11 14:15:04
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One-Step Leapfrog ADI-FDTD Method Using the Complex-Conjugate Pole-Residue Pairs Dispersion Model
摘要： A novel one-step leapfrog alternating-direction-implicit finite-difference time-domain method for the modeling of dispersive media described by the complex-conjugate pole-residue pairs model is proposed. The efficiency of the technique is demonstrated in benchmark numerical examples.
关键词： finite-difference time-domain (FDTD) method,leapfrog alternating-direction-implicit (LADI) scheme,Dispersive media
更新于2025-09-11 14:15:04
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TiO2-Au-Cu2O Photocathodes: Au-Mediated Z-Scheme Charge Transfer for Efficient Solar-Driven Photoelectrochemical Reduction
摘要： An Au-mediated Cu2O-based Z-scheme heterostructure system is demonstrated for use as efficient photocathodes in photoelectrochemical (PEC) reduction. The samples are prepared by electrodepositing a Cu2O layer on the surface of Au particle-coated TiO2 nanorods. For TiO2-Au-Cu2O, the embedded Au particles function as a charge transfer mediator to enhance the electron transportation from the conduction band of TiO2 to the valence band of Cu2O. Such a vectorial charge transfer leads to the concentration of electrons at the conduction band of Cu2O and the collection of holes at the valence band of TiO2, providing TiO2-Au-Cu2O with substantially high redox abilities for reduction applications. Time-resolved photoluminescence spectra and electrochemical impedance spectroscopy analysis suggest that interfacial charge transfer is significantly improved because of the Au-mediated Z-scheme charge transfer mechanism. By virtue of the high redox ability and improved interfacial charge transfer, TiO2-Au-Cu2O performs much better as a photocathode in H2 production and CO2 reduction than pure Cu2O and binary TiO2-supported Cu2O do. Remarkably, the photocurrent density of TiO2-Au-Cu2O toward PEC CO2 reduction can reach as high as -1.82 mA/cm2 at +0.11 V vs. RHE. The incident photon-to-current conversion efficiency data manifest that TiO2-Au-Cu2O surpasses both pure Cu2O and binary TiO2-supported Cu2O in PEC reduction across the whole photoactive region. The current study paves a valuable approach of devising Z-scheme photocathode for the construction of sophisticated artificial photosynthesis systems capable of solar-to-fuel conversion.
关键词： Au-mediated,photoelectrochemical reduction,Z-scheme,photocathode,Cu2O
更新于2025-09-11 14:15:04