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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) - A Fast Computational Algorithm to Evaluate Large Transmit-arrays
摘要： Transmit-arrays (TAs) have become popular solutions for point-to-point communications due to their low-profile and high-efficiency. However, simulation of these large and detailed structures demands a great amount of memory and time. Here, we propose a fast algorithm to estimate the performance of a beam-steering TA to accelerate its design optimization process. The results and the required resources of the algorithm are compared with the ones of Ansys HFSS. It is shown that this algorithm can fairly evaluate the key factors of the performance of a TA within couple of minutes with memory resource of only 1 GB.
关键词： computational method,transmit-arrays,Array antenna,reflect-arrays
更新于2025-09-04 15:30:14
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Porous TiO <sub/>2</sub> Nanotube Arrays for Drug Loading and Their Elution Sensing
摘要： Porous TiO2 nanotube arrays have been attracting much attention as optical sensing layers and surface layers of dental implants because they are stable in acid and biocompatible. To use them as the optical sensing layers, TiO2 nanotube arrays with various structures were fabricated and obtained an optimized microstructure at 50 V, 50 min and 0.5 wt% of NH4F, 7.4 vol% deionized water in ethylene glycol. TiO2 nanotube arrays which had diameters of ～73.54 nm and lengths of ～3.39 μm showed the best sensing performance. A Ti implant was also anodized at 60 V for 4 hr in an ethylene glycol electrolyte and TiO2 nanotube arrays showed the pore diameter of 156.01 nm and the thickness of 6.87 μm. Recombinant human bone morphogenetic protein-2 (rhBMP-2), isobutylphenyl propionic acid, and sodium alendronate were loaded into the TiO2 nanotube arrays on the surface of the Ti implant. For elution of these drugs, optical thickness changes of 2.4 nm, 3.5 nm and 3.1 nm were respectively observed for about 2.2 hr, 3.6 hr and 3.1 hr. The TiO2 nanotube arrays were useful for drug loading and their elution interferometric sensing.
关键词： Dental Implant,Porous TiO2 Nanotube Arrays,Interferometric Sensor,Isobutylphenyl Propionic Acid,Drug Delivery,rhBMP-2,Sodium Alendronate
更新于2025-09-04 15:30:14
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Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays
摘要： A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array.
关键词： three-dimensional sensing,arrays,three-dimensional image acquisition,three-dimensional image processing,thin film devices and applications,optical sensing and sensors
更新于2025-09-04 15:30:14
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Solar-charged pseudocapacitors: Simultaneous conversion and storage of solar energy in ZnO@NiO nanorod arrays
摘要： In this paper, bias-free solar-driven pseudocapacitors based on ZnO@NiO nanorod arrays had been reported, which enable the synergistic coupling of light harvesting and electrochemical storage within one single electrode. When solar-charging, ZnO/NiO PN junction served as a driving force to separate the excitons and induce electron-injection through the interface to counter electrode forming charging bias. At this bias, the OH- trapped by photoexcited holes can make redox reaction with NiO and produce electrons. As expected, under a 1-sun illumination and no external electric bias, this ZnO/NiO composite exhibits a good specific capacitance of 44.5 F g?1 at current densities of 0.5 A g?1 as well as a good cycling performance (99% capacity retention after 50 cycles). Additionally, the capacitance equation was derived to account for the boosted capacitance as the increased solar-charging time. These findings here suggest the potential of further developing light-induced electrical energy storage and release on demand by a one-component light-charged capacitors.
关键词： solar energy conversion,ZnO@NiO nanorod arrays,photo-capacitor,pseudocapacitance
更新于2025-09-04 15:30:14
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Regulation of osteoblast differentiation by osteocytes cultured on sclerostin antibody conjugated TiO2 nanotube array
摘要： Sclerostin is a negative regulator of the Wnt signaling pathway for osteoblast differentiation. In this study, osteoblasts were co-cultured with osteocytes (MLO-Y4 cells) on the surface of sclerostin antibody-conjugated TiO2 nanotube arrays (TNTs-scl). Field emission scanning electron microscopy (SEM), contact angle measurement and confocal laser scanning microscope (CLSM) were employed to characterize the conjugation of sclerostin antibody onto the surface of TiO2 nanotube arrays. The cellular viability and morphology results displayed TNTs-scl (TNT30-scl and TNT70-scl) were beneficial to the growth of MLO-Y4 cells. There was no apparent change in sclerostin gene expression between MLO-Y4 cells grown on TNTs and TNTs-scl. However, TNTs-scl significantly reduced the amount of sclerostin in the medium. In comparison with the control groups, osteoblasts displayed higher differentiation capability when co-cultured with MLO-Y4 cells on the surface TNTs-scl, which was indicated by the ALP activity, mineralization capability as well as expression levels of key proteins in Wnt signaling. This study provides a simple strategy to engineer titanium surface for bone fracture recovery, especially in osteoporotic conditions.
关键词： TiO2 nanotube arrays,osteocytes,osteogenic differentiation,Sclerostin antibody
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland, New Zealand (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Tunable Low-Frequency Broadband Dual-Polarized Rasorber
摘要： In this paper, a tunable low-frequency broadband metamaterial (MM) dual-polarized rasorber based on slot arrays has been proposed. The structure consists of one air gap sandwiched between top lossy FSS layer and bottom lossless FSS layer, which exhibits a transmission window at 1.70GHz and a -10dB broadband absorption from 0.75GHz to 3.30GHz while the thickness is less than 10% of the free space wavelength at the lowest operating frequency. A switch between absorber and rasorber can be achieved by turning PIN diodes on/off, respectively. We think the proposed rasorber can be applied in low-frequency band stealth technology. The proposed design could also be easily scaled to other frequencies if necessary.
关键词： slot arrays,metamaterial,low-frequency,broadband,rasorber,PIN diodes,tunable,FSS,dual-polarized
更新于2025-09-04 15:30:14
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Diffusive-Probabilistic Model for Inter-Pixel Crosstalk in HgCdTe Focal Plane Arrays
摘要： A closed-form probabilistic model for inter-pixel crosstalk in planar HgCdTe focal plane arrays is presented, providing simple expressions of crosstalk as function of device parameters like the pixel pitch, the absorber thickness, and the extension of the carrier depleted region. The method is effective in particular for performing parameter sensitivity studies on inter-pixel crosstalk, as an alternative to large-scale numerical simulations. The model is validated against three-dimensional combined optical and electrical numerical simulations, considering realistic, non-monochromatic illumination.
关键词： infrared detectors,crosstalk,non-monochromatic simulations,Focal plane arrays
更新于2025-09-04 15:30:14
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Electrolyte Factors Influencing Separated Pore Growth of Anodic TiO2 Nanotube Arrays
摘要： This work presents an investigation of electrolyte properties in relation to the growth of TiO2 nanotube array films, particularly concerning the measurement of conductivity in the diethylene glycol-hydrofluoric-water electrolyte system. The work aims to elucidate the behavior of ions in the anodized electrolytes with a better insight into the relation between molar conductivity and concentration of the additives. Differing solvation of the fluoride ion in various composition of water in the DEG-H2O mixture is attributed to the major factor determining the capability of proton transfer, controlling the ionic mobilities and the molar conductivities. Applying the feature of the two-factorial experiment has demonstrated a clear interaction of electrolyte parameters and titanium concentration dissolving into the electrolyte, which is believed to be a combination effect on pore widening and separating of nanotubes. A proposed schematic drawing has been demonstrated, summarizing how the nanotube arrays are constructed as a consequence of varying electrolyte type and composition.
关键词： electrochemical anodization,tube separation,TiO2 nanotube arrays,electrolyte conductivity
更新于2025-09-04 15:30:14
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - A Scalable Dual-Polarized 256-Element Ku-Band SATCOM Phased-Array Transmitter with 36.5 dBW EIRP Per Polarization
摘要： This paper presents a Ku-band dual-polarized transmit phased-array with 256-elements spaced λ/2 apart at 14 GHz in the x and y directions. The design is based on 64 silicon quad-core transmit chips with 8 channels, and these chips are used to feed a 2x2 quad antennas with dual polarizations. The output P1dB per channel is 12 dBm at 14 GHz. The silicon core-chips are flipped directly on a 12-layer low-cost printed circuit board (PCB) with stacked patch antennas and Wilkinson dividers. The 256-element phased-array results in a measured EIRP of 64.5 dBm and 66.5 dBm at P1dB and Psat, respectively, at normal incidence, per polarization. Measured patterns show a scan region of ±60° in E- and H-planes with low sidelobes and near-ideal patterns. The design achieves a cross polarization level < -27 dB up to ±45° and < -23 dB at ±60° scan angle, in both planes. The array is scalable to allow the construction of large-scale phased-arrays (1024 elements or more). To our knowledge, this represents state-of-the-art in Ku-band transmit phased-arrays in terms of integration level making it suitable for a low-cost mobile Ku-band SATCOM terminal.
关键词： silicon,phased arrays,transmit,SATCOM,antenna,beamforming,Ku-Band,PCB,14 GHz,SiGe,flip-chip
更新于2025-09-04 15:30:14
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3D heterostructured Ti-based Bi2MoO6/Pd/TiO2 Photocatalysts for High-Efficiency Solar Light Driven Photoelectrocatalytic Hydrogen Generation
摘要： Hydrogen fuel generation using solar light via photoelectrochemical (PEC) methods can help meet growing global energy demands and decrease environmental pollution. The key to efficient PEC hydrogen production is the synthesis of solar light driven photoelectrodes with efficient charge carrier separation. Here, we designed and prepared a ternary Bi2MoO6/Pd/TiO2 photoelectrode composed of Bi2MoO6 nanosheets, Pd nanoparticles (NPs) and TiO2 nanotube arrays (NTAs) on a Ti substrate using electrochemical methods. This novel photoelectrode had good visible light absorbance and significantly improved PEC hydrogen production rates (~5 and > 15 times higher under UV-vis and visible light irradiation, respectively, compared with TiO2 NTAs). The interfacial charge transfer mechanism of Bi2MoO6/Pd/TiO2 NTAs was comprehensively studied by comparing its PEC and photoelectrocatalytic performance with other TiO2 NTAs (i.e. Pd/TiO2 NTAs, Bi2MoO6/TiO2 NTAs and Pd/Bi2MoO6/TiO2 NTAs). For Bi2MoO6/Pd/TiO2 NTAs, Pd NPs homogeneously dispersed across the inside and outside of TiO2 nanotube walls helped to tightly anchor Bi2MoO6 nanosheets onto the TiO2 surface, forming a ternary 3D heterostructure. This structure facilitated interfacial electron injection from Bi2MoO6 to TiO2, accelerating the separation of the photogenerated electron-hole pairs. And significantly enhanced the photocurrent response and hydrogen production rate were achieved compared with other TiO2 NTAs. This 3D ternary semiconductor/metal/semiconductor heterojunction provides a viable approach for designing and synthesizing highly efficient novel photocatalysts that can effectively utilize solar energy.
关键词： TiO2 nanotube arrays,Pd nanoparticles,Bi2MoO6 nanosheets,Photoelectrocatalytic hydrogen production,Ternary photocatalyst
更新于2025-09-04 15:30:14