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PRIMA subretinal wireless photovoltaic microchip implantation in non-human primate and feline models
摘要： Purpose To evaluate the surgical technique for subretinal implantation of two sizes of PRIMA photovoltaic wireless microchip in two animal models, and refine these surgical procedures for human trials. Methods Cats and Macaca fascicularis primates with healthy retina underwent vitrectomy surgery and were implanted with subretinal wireless photovoltaic microchip at the macula/central retina. The 1.5mm PRIMA chip was initially studied in feline eyes. PRIMA implant (2mm,1.5mm sizes) arrays were studied in primates. Feasibility of subretinal chip implantation was evaluated with a newly-developed surgical technique, with surgical complications and adverse events recorded. Results The 1.5mm implant was placed in the central retina of 11 feline eyes, with implantation duration 43–106 days. The 1.5mm implant was correctly positioned into central macula of 11 primate eyes, with follow-up periods of minimum 6 weeks (n = 11), 2 years (n = 2), and one eye for 3 years. One primate eye underwent multi-chip 1.5mm implantation using two 1.5mm chips. The 2mm implant was delivered to 4 primate eyes. Optical coherence tomography confirmed correct surgical placement of photovoltaic arrays in the subretinal space in all 26 eyes. Intraoperative complications in primate eyes included retinal tear, macular hole, retinal detachment, and vitreous hemorrhage that resolved spontaneously. Postoperatively, there was no case of significant ocular inflammation in the 1.5mm implant group. Conclusions We report subretinal implantation of 1.5mm and 2mm photovoltaic arrays in the central retina of feline and central macula of primate eyes with a low rate of device-related complications. The in vivo PRIMA implantation technique has been developed and refined for use for a 2mm PRIMA implant in ongoing human trials.
关键词： photovoltaic microchip,primate model,PRIMA,feline model,surgical technique,subretinal implantation
更新于2025-09-19 17:13:59
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Facile synthesis, structure analysis and optical performance of manganese oxide-doped PVA nanocomposite for optoelectronic and optical cut-off laser devices
摘要： In the present work, successful manganese oxide (Mn2O3) nanoparticles (NPs) were synthesized by a combustion technique, while the casting process was employed for the manufacturing of polymer nanocomposites with various weights of Mn2O3 based on Poly(Vinyl Alcohol), PVA. Multiple methods such as X-ray diffraction (XRD), HR-TEM, EDAX, EDS, SEM, FT-IR, DTA analysis, optical spectroscopy from UV to IR regions, and optical reduction (CUT-OFF) setup were used to characterize the structural, elemental chemical analysis, morphological, optical properties, and cut-off laser characteristic of nanocomposite samples. Mn2O3 nanoparticles have a crystallite size of 22.08 nm as calculated using the Debye–Scherer formula from XRD, while the HR-TEM shows a spherical particle of size 30–38 nm range. EDAX spectra and EDS mapping were used to detect the elemental particles of the nanocomposite. The external morphology of the films by SEM images shows an increase in the agglomeration size of the cluster with the percentage of Mn2O3 nanoparticles in PVA. FT-IR spectra show excellent incorporation between the matrix of polymer and the Mn2O3 via the hydroxyl group. Moreover, with increasing the doping rate of nanoparticles, the thermal stability of PVA increased. A significant change of optical transmittance, absorption edge, Urbach energy, and transition bandgap have been observed due to the influence of Mn2O3. The comparison between the bandgap values that have been estimated from Tauc’s relation and thus resulting from optical dielectric loss indicates a direct allowed transition of electrons in the nanocomposites. The light is entirely UV–Vis absorbed by PVA with a high percentage of Mn2O3 nanoparticles. Moreover, the efficiency of the films to decrease the power of two laser beams (635 nm and 533 nm) has been observed. The flexible films of PVA with an elevated rate of Mn2O3 are considered a successful option for low-cost technologies of optical limiting.
关键词： Casting process,Combustion technique,PVA nanocomposite,Optoelectronic,Manganese oxide,Optical cut-off laser devices
更新于2025-09-19 17:13:59
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Effects of inhomogeneous laser field in time and space on the generation of broad spectral continuum and ultrashort attosecond pulse
摘要： The inhomogeneous effects of laser field in time and space on the generations of high-order harmonic spectra and attosecond pulses from He atom have been investigated with the assistance of the frequency-chirping technique and the metallic nanostructure. We find that in different combinations of chirps and spatial inhomogeneous effects, not only can the harmonic cutoff be extended, but the single harmonic emission peak (HEP) can also be selected to contribute to the spectral continuum. In detail, with the combinations of (i) symmetric chirp in frequency and positive inhomogeneous effect in space or (ii) asymmetric down chirp in frequency and negative inhomogeneous effect in space, two broad spectral continua with bandwidths of 496 eV and 480 eV can be obtained. Further, by properly adding IR or UV controlling pulse, the harmonic emission efficiency can be enhanced by several orders of magnitude. The enhancement of harmonic yield from adding UV pulse is higher than that from adding IR pulse. Moreover, the difference of harmonic enhancement between UV combined field and IR combined field is much more obvious at lower controlling laser intensity. Through analyzing the ionization probability, we find that the higher enhancement of harmonic yield from UV combined field is because of UV-resonance-enhancement-ionization between the ground state and the excited state of He atom. Finally, by properly superposing some harmonics, a number of attosecond pulses with pulse durations of 45 as can be obtained.
关键词： frequency-chirping technique,High-order harmonic generation,two-color field,inhomogeneous effect in space,ultrashort attosecond pulse
更新于2025-09-19 17:13:59
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Determination of Laser Tracker Angle Encoder Errors
摘要： Errors in the angle encoders of a laser tracker may potentially produce large errors in long range coordinate measurements. To determine the azimuth angle encoder errors and verify their values stored in the tracker’s internal error map, several methodologies were evaluated, differing in complexity, measurement time and the need for specialised measuring equipment. These methodologies are: an artefact-based technique developed by NIST; a multi-target network technique developed by NPL; and the classical precision angular indexing table technique. It is shown that the three methodologies agree within their respective measurement uncertainties and that the NPL technique has the advantages of a short measurement time and no reliance on specialised measurement equipment or artefacts.
关键词： Precision Angular Indexing Table,NIST technique,NPL network technique,Angle Encoder Errors,Laser Tracker
更新于2025-09-16 10:30:52
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[IEEE 2019 4th World Conference on Complex Systems (WCCS) - Ouarzazate, Morocco (2019.4.22-2019.4.25)] 2019 4th World Conference on Complex Systems (WCCS) - An Accurate Photovoltaic Source Emulator with High-Bandwidth Using a Backstepping Controller
摘要： This paper presents the design and development of a photovoltaic (PV) source emulator able to behave similarly as an actual PV module irrespective of environmental conditions change, it consists basically of a switch mode power supply (SMPS) controlled by a backstepping technique with a control strategy of referencing. The backstepping strategy is used to guaranty more accuracy and stability of the system and ensure a high bandwidth in order to track faithfully the Current-Voltage (I-V) characteristic of a desired PV module. Simulation results are given and discussed so as to validate the functioning of the proposed PV emulator as well as evaluate the performances of the suggested control technique in terms of accuracy, speed, and robustness against load and weather parameters variation.
关键词： Backstepping technique,control strategy,PV array emulator,buck converter
更新于2025-09-16 10:30:52
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Electro-Hydrodynamic Design of an Intelligent Balloon Water Gate Controlled by an Efficient Maximum-Power-Seeking Controller for a Solar Generation System
摘要： The intelligent balloon water gate (IBWG) invention is a hydraulic gate model made of reinforced plastic that controls the water level (WL) downstream or upstream of a barrage. The IBWG automatically in?ates and de?ates by compressed air to close and open the water passage, respectively. The whole design consists of a balloon, a waterway, sensors, an air compressor, a control panel, an electrical circuit and a photovoltaic generation (PVG) system. The Tyass barrage in Iraq was considered as a case study. The Tyass barrage was built with concrete and four sliding steel water gates and redesigned using the IBWG. The originality of the current research resides in the combination of the IBWG mechanism with an ef?cient maximum power point (MPP) seeking controller for a photovoltaic generation system, which is one of the most promising sources of renewable energy in the world. To the best of our knowledge, in this ?eld, this scenario has not yet been discussed in detail. Upper and lower water sensors are used to control the IBWG. The upper sensor sends a signal to the control panel when the downstream water level reaches its maximum value to open the air inlet valve and close the outlet valve, in?ating 14 IBWGs with a volume of 3.5 m3 under 122 psi of pressure and closing the water passage. When the WL decreases below the minimum level, the lower sensor initiates the opposite procedure. The air compressor automatically ?lls the air tank to 181 psi and is supplied by a 24 VDC AGM rechargeable battery with a capacity of 40-60 Ah, which is charged by four solar panels connected in parallel and exposed to an average of 8.8 hrs/day of sunshine. The proposed MPP-seeking controller was implemented by a backstepping design coupled with the grey wolf mechanism. The solar irradiance data were observed 39 years ago. The proposed controller is capable of following the MPP with minimum oscillations under an external irradiance variation. The IBWG system is veri?ed at night or during the early morning when the sun is not active. Nevertheless, it is possible to store compressed air in an auxiliary tank to avoid emergencies such as partial shading conditions.
关键词： PVG system,backstepping technique,lyapunov stability,grey wolf optimization,Electro-hydrodynamic rubber water gate
更新于2025-09-16 10:30:52
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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) - Thermal Analysis of New Ionic Liquids by EZ-Scan Technique
摘要： Many organic materials have been developed and studied aiming photonic aplications. Ionic liquids (IL) are organic materials in the class of molten salts and they presents many interesting physicochemical properties. IL are used in batteries, they are good stabilizers for colloidal suspensions and also green solvents for chemical reactions and processes [1]. Two new ionic liquids synthetized, BMIOMe.NTf2 and BMIOMe.N(CN)2, evidenced an alteration in the electrical conductivity when illuminated with a Xe-lamp. One hypothesis of this change of conductivity is related to the increase of carrier density. An increase of charger mobility due to thermal effects could also coperate with this modification. Besides the usual fast electronic nonlinearity, we characterize the thermal response for both IL synthetized by EZ-scan technique [2,3] in order to verify how strong is the linear absorption converted in nonradioative decay and change of sample temperature.
关键词： Ionic liquids,EZ-scan technique,thermal analysis,photonic applications
更新于2025-09-16 10:30:52
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[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Fabrication of Cavity-Sealed Optical Interferometric Surface Stress Biosensor by thin Film Transfer Technique
摘要： We developed a surface stress sensor based on a MEMS Fabry-Perot interferometer with cavity-sealed structure by technique of nanometer-thick parylene sheet for highly sensitive label-free biosensing. The proposed MEMS interferometer can measure the membrane deflection caused by target molecule adsorption as the spectral shift. The proposed cavity-sealed optical interferometer can prevent physical adsorption to the backside of membrane and refractive index drift in the cavity, leading to improvement of sensitivity. We successfully obtained the spectral shift of 77 nm in 10 minutes with the color change associated with the antigen-antibody reaction with a concentration of 1 ng/ml, which improved by 16.7-fold compared with the conventional sensor.
关键词： MEMS biosensor,Surface stress sensor,label-free biosensing,film transfer technique,Fabry-Perot interferometer
更新于2025-09-16 10:30:52
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Novel Gd3+-doped silica-based optical fiber material for dosimetry in proton therapy
摘要： Optical fibers hold promise for accurate dosimetry in small field proton therapy due to their superior spatial resolution and the lack of significant Cerenkov contamination in proton beams. One known drawback for most scintillation detectors is signal quenching in areas of high linear energy transfer, as is the case in the Bragg peak region of a proton beam. In this study, we investigated the potential of innovative optical fiber bulk materials using the sol-gel technique for dosimetry in proton therapy. This type of glass is made of amorphous silica (SiO2) and is doped with Gd3+ ions and possesses very interesting light emission properties with a luminescence band around 314 nm when exposed to protons. The fibers were manufactured at the University of Lille and tested at the TRIUMF Proton Therapy facility with 8.2–62.9 MeV protons and 2–6 nA of extracted beam current. Dose-rate dependence and quenching were measured and compared to other silica-based fibers also made by sol-gel techniques and doped with Ce3+ and Cu+. The three fibers present strong luminescence in the UV (Gd) or visible (Cu,Ce) under irradiation, with the emission intensities related directly to the proton flux. In addition, the 0.5 mm diameter Gd3+-doped fiber shows superior resolution of the Bragg peak, indicating significantly reduced quenching in comparison to the Ce3+ and Cu+ fibers with a Birks’ constant, kB, of (0.0162 ± 0.0003) cm/MeV in comparison to (0.0333 ± 0.0006) cm/MeV and (0.0352 ± 0.0003) cm/MeV, respectively. To our knowledge, this is the first report of such an interesting kB for a silica-based optical fiber material, showing clearly that this fiber presents lower quenching than common plastic scintillators. This result demonstrates the high potential of this inorganic fiber material for proton therapy dosimetry.
关键词： Bragg peak,dosimetry,Gd3+-doped silica,optical fibers,quenching,sol-gel technique,proton therapy
更新于2025-09-16 10:30:52
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[IEEE 2019 6th International Conference on Space Science and Communication (IconSpace) - Johor Bahru, Malaysia (2019.7.28-2019.7.30)] 2019 6th International Conference on Space Science and Communication (IconSpace) - Integration of NiO Layer as Hole Transport Material in Perovskite Solar Cells
摘要： A successful integration of inorganic hole transporting material (HTM) for perovskite become one of the major concerns due to the instability issue with organic HTM. Inorganic NiO films as an efficient HTM for the inverted perovskite solar cell has been deposited by electron beam vapor deposition (EBPVD) technique instated of solution process. The X-Ray diffraction (XRD) peak of as-deposited substrate corresponding to (1 1 1) and (2 0 0) plane are dominating. The non-stoichiometry (1 1 1) in NiO thin film formation at influence its charge transfer characteristics. The FESEM confirms the successful non-stoichiometric deposition of NiO on FTO glass in an elemental wt% of O2 (15.82) and Ni (23.62). The perovskite structure of solar cells are fabricated Glass/TCO/NiO/Perovskite/PCBM/BCP/Ag. The deposited perovskite solar cells show higher power conversion efficiency (PCE) 10.80% with short circuit current density (Jsc) of 15.13 (mA cm-2), open circuit voltage (Voc) of 0.967 (V), field factor (FF) of 73.83 (%) which also allows thinking of an alternative HTL other than organic HTL for realistic commercial purpose.
关键词： Perovskite solar cell,hole transporting materials,nickel oxide,vapor deposition technique,power conversion efficiency
更新于2025-09-16 10:30:52