A capacitively-loaded passive RFID temperature sensor tag working at UHF band is designed and tested. A cavity backed slot antenna is designed as the tag antenna. In order to realize high temperature sensitivity, the ...
详细信息
A capacitively-loaded passive RFID temperature sensor tag working at UHF band is designed and tested. A cavity backed slot antenna is designed as the tag antenna. In order to realize high temperature sensitivity, the Polytetrafluoroethylene (PTFE) material which has a large thermal expansion of 140ppm/°C is used as the temperature sensing material. A copper coated PTFE post is placed at the center of the cavity, which is in close proximity to the cavity ceiling. Thus, a loaded capacitor is generated between the PTFE surface and the cavity ceiling. As the temperature increases, the PTFE will approach to the cavity ceiling due to the thermal expansion, and thus change the loaded capacitance; therefore, the resonant frequency of the slot antenna will change accordingly. By distinguishing the resonant frequency of the antenna, the temperature information is obtained. The simulation results show that this design provides a frequency shift of 30MHz/10°C and a read range of 10.5m.
We demonstrate the integration of GaAs thin-film solar cells with low-cost plastic mini-compound parabolic concentrators (CPC) by combing a non-destructive epitaxial lift-off (ND-ELO) technique and a vacuum-assisted t...
详细信息
ISBN:
(纸本)9781479943975
We demonstrate the integration of GaAs thin-film solar cells with low-cost plastic mini-compound parabolic concentrators (CPC) by combing a non-destructive epitaxial lift-off (ND-ELO) technique and a vacuum-assisted thermoforming process. To simplify the thin film III-V active layer transfer and to eliminate the use of adhesives of the epi to the secondary plastic substrate, we employ cold-weld bonding. The integration of thin film GaAs photovoltaic cells with a low-cost plastic mini CPC that can track solar radiation increases energy harvesting by a factor of 2. The Combination of cost effective concentrators with previously demonstrated non-destructive wafer recycling utilizing epitaxial protection layers provides the potential for a dramatic cost reduction in the production of III-V semiconductor photovoltaic cells.
engineering research may provide tools to the individual as well as to the public in general, to effectively monitor welness and health patterns, such as metabolic rate and weight control. Ketone bodies and acetone ga...
详细信息
engineering research may provide tools to the individual as well as to the public in general, to effectively monitor welness and health patterns, such as metabolic rate and weight control. Ketone bodies and acetone gas emissions in exhaled breath and skin, in particular, may be used as biomarkers of fatty acid metabolism and may be used in diet control. Two types of technologies, resistive chemosensors and chemomechanical actuators are outlined here as examples of such tools currently under development and of great promise.
Confocal photoluminescence scans of monocrystalline CdTe/MgCdTe double heterostructures epitaxially grown on lattice-matched InSb substrates reveal very low twin defect density, below 1 × 10 5 cm -2 . Room-tempe...
详细信息
Confocal photoluminescence scans of monocrystalline CdTe/MgCdTe double heterostructures epitaxially grown on lattice-matched InSb substrates reveal very low twin defect density, below 1 × 10 5 cm -2 . Room-temperature Shockley-Read-Hall (SRH) lifetimes of these samples are determined in the range of 35 ns to 86 ns using time-resolved photoluminescence (TRPL) measurements. Temperature-dependent TRPL measurements show that the carrier lifetime reaches a peak of 910 ns at 200 K. Excitation-dependent PL measurements reveal the radiative recombination coefficient of CdTe to be 4.3 × 10 -9 cm 3 ·s -1 .
Correction for ‘Fibrous and flexible supercapacitors comprising hierarchical nanostructures with carbon spheres and graphene oxide nanosheets’ by Xiong Zhang et al., J. Mater. Chem. A, 2015, DOI: 10.1039/c5ta03252k.
Correction for ‘Fibrous and flexible supercapacitors comprising hierarchical nanostructures with carbon spheres and graphene oxide nanosheets’ by Xiong Zhang et al., J. Mater. Chem. A, 2015, DOI: 10.1039/c5ta03252k.
We measured the lifetime of optically created valley polarization in single-layer WS2 using transient absorption spectroscopy. The electron valley relaxation is very short (<1 ps). However, the hole valley lifetime...
We measured the lifetime of optically created valley polarization in single-layer WS2 using transient absorption spectroscopy. The electron valley relaxation is very short (<1 ps). However, the hole valley lifetime is at least two orders of magnitude longer and exhibits a temperature dependence that cannot be explained by single-carrier spin/valley relaxation mechanisms. Our theoretical analysis suggests that a collective contribution of two potential processes may explain the valley relaxation in single-layer WS2. One process involves direct scattering of excitons from K to K′ valleys with a spin flip-flop interaction. The other mechanism involves scattering through the spin-degenerate Γ valley. This second process is thermally activated with an Arrhenius behavior due to the energy barrier between the Γ and K valleys.
We report an in situ experimental characterization method of nanoelectrochemical systems (NECSs). Experiments were performed using nanorobotic manipulation inside a transmission electron microscope together with an el...
详细信息
We report an in situ experimental characterization method of nanoelectrochemical systems (NECSs). Experiments were performed using nanorobotic manipulation inside a transmission electron microscope together with an electrochemical work station. The electrochemical behavior of an Mg-MgO-MoS 2 heterostructure demonstrated the potential application of Mg as an anode for an ion-battery. Due to the abundant amount of magnesium on the earth, the investigation promises a low-cost anode material for a new generation of batteries. The application of 2D layered MoS 2 crystals also provides a solution of using layered nanostructures as high-capacity cathodes. Several key techniques for in situ nanoelectrochemical investigations were also presented in this report.
Nickel germanide formed on amorphous and crystalline germanium is investigated for material and electrical properties. The crystal quality of films formed is poorer for the germanides formed on amorphous germanium wit...
详细信息
Nickel germanide formed on amorphous and crystalline germanium is investigated for material and electrical properties. The crystal quality of films formed is poorer for the germanides formed on amorphous germanium with a slight increase in sheet resistance. The grains of NiGe formed on amorphous germanium show a growth that is hexagonal like, extending into the substrate further than germanides grains formed on crystalline germanium. The NiGe formed on crystalline germanium has a much more uniform thickness and uniform grain size and shape. Hollow cone illumination shows that some recrystallisation of the amorphised region of germanium does occur.
暂无评论