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101.
《Current Applied Physics》2015,15(5):622-631
Lithium (Li) (0–5 wt%) doped V2O5 thin films were spray deposited at 450 °C onto ITO substrates. Structural analysis using X-ray diffraction and Raman spectroscopy revealed orthorhombic phase of the films. In addition to the V2O5 phase, presence of VO2 peaks due to high deposition temperature is also evident from structural and optical characterization. The non-stoichiometric nature of the films due to loss of the terminal O atom was confirmed from Raman spectroscopy. The direct band gap, indirect bandgap, and phonon energies were also calculated from optical studies. Different charge states of vanadium ions present in the film were identified from X-ray photoelectron spectroscopy study. Results from cyclic voltammetry experiments reflected significant differences between the undoped and Li doped V2O5 samples. Transport properties by Hall-effect measured at room temperature indicated significant increase in conductivity, carrier concentration and mobility of V2O5 thin films on doping with Li. A Dye Sensitized Solar Cell (DSSC) was fabricated using mobility enhanced 5 wt% Li doped V2O5 film as photoanode and its efficiency was found to be 2.7%. A simple electrochromic cell is fabricated using undoped V2O5 thin film to demonstrate the colour change. 相似文献
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THOMAS C. JEDREY EDGAR H. SATORIUS MARTIN J. AGAN 《International Journal of Satellite Communications and Networking》1996,14(3):191-200
This paper presents a new open-loop technique for estimating and correcting Doppler frequency shift in K/Ka-band communication systems with special reference to the advanced communications technology satellite (ACTS) mobile terminal (AMT) modem, which utilizes square-wave pulse-shaped, binary differential phase shift-keyed (DPSK) modulation. The novelty of this estimation scheme is that it exploits the Doppler-induced phase shift over a fraction of a symbol interval to provide an estimate of the Doppler offset, without requiring symbol synchronization. Furthermore, by utilizing time-differential detection (delay-and-multiply), the proposed technique can tolerate much larger frequency offsets than existing open- or closed-loop techniques. Analytical results are provided for the variance of the above estimator and the error probability performance of the AMT is evaluated in the presence of the Doppler correction. Practical design considerations are also discussed, including a method for modifying the front end, digital bandlimiting filter in such a way that Doppler bias effects in the new estimator are eliminated. Simulation results reveal that, in general, performance improves with increasing data rates, i.e., the new frequency offset estimation/compensation algorithm induces a degradation from ideal of approximately 1 dB at a 6 dB energy per data symbol (bit) and a 2⋅4 kbps data rate. However, there is no appreciable degradation when the data rate is increased to 9⋅6 or 19⋅2 kbps. 相似文献
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随着5G商用牌照的发放,5G基站建设如火如荼地开展,5G基站的基础配套的改造需求变得越来越紧迫.现有基站的配套能力如何满足5G建设的需要,成为亟需面对和解决的问题.通过分析三大运营商5G网络的特点和架构,同时考虑多家运营商共享情况,并根据5G网络建设实施情况分析5G基站的塔桅抱杆、电源和外电的配套改造方案. 相似文献
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微波技术在视频图像无线传输中的应用 总被引:3,自引:0,他引:3
电视监控在生活和工作中得到了广泛的应用,然而在某些环境中,由于成本或地形所限,有线电视监控无法实现.无线网络产品的快速发展和视频压缩标准的日渐完善对此提供了良好的解决方案.从工程的角度阐述了两种常用微波扩频技术的原理和特点,结合实际应用环境,对频点的选取、扩频技术的采用、天线的选择与调整提出了具体的方法. 相似文献
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Yoongook Park 《Molecular Crystals and Liquid Crystals》2020,705(1):135-140
AbstractOptically clear adhesives (OCAs) are widely used in optoelectronic displays because of their high outdoor visibility. Here, we develop new transparent adhesive films with wide-viewing-angle characteristics using poly(methyl methacrylate) (PMMA)/TiO2 core–shell micro/nanoparticles. TiO2 nanoparticles are embedded in the shell of PMMA microparticles, forming an organic–inorganic hybrid structure. To examine the optical transmittance of the films in the visible wavelength region, ultraviolet-visible spectroscopy is performed and light diffusion is evaluated. The TiO2 nanoparticles in the shell of the PMMA microparticles exhibit improved light scattering, and the new functional OCAs are expected to provide wide-viewing-angle characteristics for future flexible displays. 相似文献