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Discharges of plasma induced by hypervelocity impact on the solar array with different substrate structures1
摘要： The purpose of the paper is to investigate the discharge of the plasma generated by a projectile hypervelocity impact on solar array with three kinds of different substrates at the 60? incidence angle and the external applied voltage of 100 voltage. Four sets of experiments were performed to impact solar arrays with CFRP Aluminum honeycomb sandwich substrate, Aluminum honeycomb sandwich substrate and the aluminum substrate by using two-stage light gas gun loading system and discharge measurement system established. Experimental results showed that discharge voltage and discharge current of the solar array with CFRP Aluminum honeycomb sandwich substrate are the most strongest among the solar array with CFRP Aluminum honeycomb sandwich substrate, Aluminum honeycomb sandwich substrate and the aluminum substrate. This work will be helpful to improve the material and substrate’ structure of the solar arrays in spacecrafts.
关键词： Hypervelocity impact,solar array with different substrate,discharge voltage,plasma,discharge current
更新于2025-09-04 15:30:14
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Reconfigurable rectenna array design with mutual coupling analysis
摘要： This article introduces design of two frequency reconfigurable rectenna arrays, which are in direct current (DC) combining and in radio frequency (RF) combining configurations, respectively, with the mutual coupling analysis. We compare the performances in the conversion efficiency of the two arrays. For the mutual coupling analysis, the coupling coefficient matrix and the active DC patterns of the two rectenna arrays are calculated. By analyzing the mutual coupling, we find that the rectenna array in RF combining can achieve higher and more stable output DC power than that in DC combining. When the receiving antenna element spaces about 0.46λ0 and the rectifying circuit element spaces 0.17λ0, the proposed two-element reconfigurable rectenna array in RF combining configuration achieves measured conversion efficiencies of 69.1% and 64.2% at two operation frequency modes, while simulated efficiency in DC configuration achieves 70.3% and 53.2% when the rectenna element spaces 0.38λ0.
关键词： microwave power transmission,rectenna array,mutual coupling,DC combining,RF combining
更新于2025-09-04 15:30:14
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Medium- to long-term survival and functional examination of human iPSC-derived retinas in rat and primate models of retinal degeneration
摘要： Background: We have previously reported that xeno-transplanted human ESC-derived retinas are able to mature in the immunodeficient retinal degeneration rodent models, similar to allo-transplantations using mouse iPSC-derived retina. The photoreceptors in the latter developed outer segments and formed synapses with host bipolar cells, driving light responses of host retinal ganglion cells. In view of clinical application, here we further confirmed the competency of human iPSC-derived retina (hiPSC-retina) to mature in the degenerated retinas of rat and monkey models. Methods: Human iPSC-retinas were transplanted in rhodopsin mutant SD-Foxn1 Tg(S334ter)3LavRrrc nude rats and two monkeys with laser-induced photoreceptor degeneration. Graft maturation was studied by immunohistochemistry and its function was examined by multi-electrode array (MEA) recording in rat retinas and visually-guided saccade (VGS) in a monkey. Findings: A substantial amount of mature photoreceptors in hiPSC-retina graft survived well in the host retinas for at least 5 months (rat) to over 2 years (monkey). In 4 of 7 transplanted rat retinas, RGC light responses were detected at the grafted area. A mild recovery of light perception was also suggested by the VGS performance 1.5 years after transplantation in that monkey. Interpretation: Our results support the competency of hiPSC-derived retinas to be clinically applied for transplantation therapy in retinal degeneration, although the light responses observed in the present models were not conclusively distinguishable from residual functions of degenerating host retinas. The functional analysis may be further elaborated using other models with more advanced retinal degeneration.
关键词： Human iPSC,Retinal degeneration,Photoreceptor transplantation,Visually-guided saccades,Multi-electrode array
更新于2025-09-04 15:30:14
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Polymer conductive fabric grid array antenna with pliable feature for wearable application
摘要： A flexible microstrip grid array antenna designed on polydimethylsiloxane (PDMS) substrate and copper conductive fabric as the patch and ground plane is presented. The proposed geometry designed at 15 GHz is made of 19 cells with 22 radiating elements. The proposed antenna achieves almost 40% wideband characteristics at ?10 dB reflection coefficient from 11.10 GHz until 16.2 GHz with measured maximum gain of 14.0 dBi in normal state. Analysis on performance of antenna at bend state with various value of bend radius has been done. The measured reflection coefficient shows low sensitivity to bending effect where the antenna operates well at designed frequency which is at 15 GHz. Due to these criteria, it is a suitable candidate for wearable applications.
关键词： 5G,microstrip grid array antenna (MGAA),conductive fabric,PDMS
更新于2025-09-04 15:30:14
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[Advances in Intelligent Systems and Computing] Soft Computing for Problem Solving Volume 816 (SocProS 2017, Volume 1) || Detecting Image Forgery in Single-Sensor Multispectral Images
摘要： With the advancements in digital technology, multispectral images have found use in ?elds like forensics, remote sensing due to their ability to perceive things which were otherwise non-existent. They are used to obtain more information about terrains, land cover and in forensics as certain things like blood stains are not visible in visible spectrum. But with newly developed photo-editing softwares, they can be easily manipulated without leaving any visible clue of manipulation, but will destroy the underlying correlation between different bands. Newly developed digital cameras employ a single sensor along with multispectral ?lter array (MSFA) and then interpolate the data at other locations, hence introducing a correlation between bands. In this paper, we have proposed an algorithm that can identify the lack of correlation at tampered locations in a multispectral image and can thus help in establishing the authenticity of the given multispectral image. We show the ef?ciency of our approach with respect to the size of tampered regions in images interpolated with one the most common demosaicking algorithm—binary tree-based edge sensing (BTES).
关键词： Multispectral ?lter array (MSFA),Interpolation,MSFA demosaicking,EM algorithm,Multispectral image forgery
更新于2025-09-04 15:30:14
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[IEEE 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro) - Bento Gon?alves, Brazil (2018.8.27-2018.8.31)] 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro) - Non uniformity correction in a Long Wave Infrared Focal Plane Array as a function of the higher calibration temperature
摘要： It is well known that every detector in a Focal Plane Array (FPA) has a different responsivity and offset. These variations result in a specific kind of noise, the Fixed Pattern Noise (FPN) or spatial noise. During the image processing, those pixels who has a large deviation in responsivity are considered a bad pixel, and has its value removed of FPA. Knowing the answer of in a FPA all those pixels are the first test procedure characterization. However, during the bad pixels analysis it is necessary to choose two reference temperatures, calibration points, and those temperature affects important parameters such as Uniformity, Noise Equivalent Temperature Difference (NETD) and Signal Transfer Function (SiTF). This work will study the influence of higher calibration temperature on the Non-Uniformity Correction (NUC) quality.
关键词： Focal Plane Array,Uniformity,Signal Transfer Function,Noise Equivalent Temperature Difference,Long Wave Infrared
更新于2025-09-04 15:30:14
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Facile Synthesis of ZnO Nanorods/GO Composite and Its Optical Performance
摘要： The ZnO nanorods/GO composite was fabricated by facilely covering monolayer or few-layer graphene oxide (GO) film on the uniformly distributed ZnO nanorods, which was synthesized on Si substrate using a solution method. The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), as well as X-ray diffraction (XRD). The photoluminescence (PL) measurement indicates that the ZnO nanorods have a strong ultraviolet (UV) emission centered at ～391 nm attributed to the recombination of free excitons and a defect-related visible emission centered at ～530 nm. After the nanorods were covered with GO film, the PL intensity of the composite is quenched compared to that of the bare one at the same excitation condition. The fluorescence quenching mechanism suggests that there is an interfacial charge-transfer process between the excited ZnO and the GO film, and the composite fabricated in this experiment be possible to improve the photocatalysis performance.
关键词： Photocatalyst,Nanorod Array,Zinc Oxide,Graphene Oxide,Fluorescence Quenching
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - SIW Based Antenna Array with Power Equalization in Elevation Plane for 5G Base Stations
摘要： In this paper, we present a 5G base station phased array antenna concept based on the power flux equalization in the elevation plane. We designed an aperture- coupled microstrip patch sub-array fed by a substrate integrated waveguide to produce a cosecant radiation pattern in the elevation plane. The antenna is designed to be operational at frequencies around 28.5GHz, targeting a candidate 5G mm-wave frequency band. The dimensions of the cosecant antenna sub-array support wide-angle scanning of the final phased array antenna in the horizontal plane. The antenna exhibits good impedance and radiation properties in the scanning range +/- 45deg.
关键词： cosecant radiation pattern,microstrip patch antenna,substrate integrated waveguide,phased array antenna,5G base station
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Multi-Polarization Planar Dipole Array Surface for Electromagnetic Energy Harvesting and Wireless Power Transfer
摘要： We present a design of a multi-polarization electromagnetic energy harvesting surface inspired by a multi-layer unit cell of printed asymmetrical metallic dipolar elements. The harvesting array features two layers that collectively capture the incident energy from various incident angles. The harvester was ?rst analyzed for maximizing radiation to AC absorption where each dipole was terminated by a resistor across its energy-collecting gap. The simulation results show an average ef?ciency of 90% for the radiation to AC conversion at various incident angles. As a proof of concept, a multi-layer array consisting of 3x3 asymmetrical dipolar elements of the de?ned multi-layer unit cell was fabricated and measured experimentally. The experimental results yielded an overall radiation to DC harvesting ef?ciency of 70% for multiple incident polarizations.
关键词： dipole array,electromagnetic absorber,wireless power transfer,rectennas,Energy harvesting,recti?cation
更新于2025-09-04 15:30:14
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Effect of drain current on appearance probability and amplitude of random telegraph noise in low-noise CMOS image sensors
摘要： Random telegraph noise (RTN), which occurs in in-pixel source follower (SF) transistors, has become one of the most critical problems in high-sensitivity CMOS image sensors (CIS) because it is a limiting factor of dark random noise. In this paper, the behaviors of RTN toward changes in SF drain current conditions were analyzed using a low-noise array test circuit measurement system with a ?oor noise of 35 μVrms. In addition to statistical analysis by measuring a large number of transistors (18048 transistors), we also analyzed the behaviors of RTN parameters such as amplitude and time constants in the individual transistors. It is demonstrated that the appearance probability of RTN becomes small under a small drain current condition, although large-amplitude RTN tends to appear in a very small number of cells.
关键词： source follower (SF) transistors,drain current,CMOS image sensors (CIS),Random telegraph noise (RTN),low-noise array test circuit
更新于2025-09-04 15:30:14