The film thickness dependent thermal stability of Al2O3:Ag thin films as high-temperature solar selective absorbers

The monolayer Al2O3:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 degrees C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al2O3:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 degrees C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al2O3:Ag thin films as high-temperature solar selective absorbers.</p

Intra and Inter-PON ONU to ONU Virtual Private Networking using OFDMA in a Ring Topology

Abstract—In this paper, we propose a novel WDM-PON architecture to support efficient and bandwidth-scalable virtual private network (VPN) emulation over both inter-PON and intra- PON. The virtual ring link for the VPN communications among ONUs is realized by using additionally low-cost optical passive components and OFDMA technology. Moreover, the downstream traffic wavelength is reused for the upstream traffic signal by using re-modulation technology. We report on a successful transmission of 10.7 Gbps OOK upstream and 10.7 Gbps DPSK downstream, together with 1.25 Gbps 16-QAM OFDM VPN traffic, over 20 km no-zero dispersion shifted fiber (NZDSF). In this paper, we propose a novel WDM-PON architecture to support efficient and bandwidth-scalable virtual private network (VPN) emulation over both inter-PON and intra-PON. The virtual ring link for the VPN communications among ONUs is realized by using additionally low-cost optical passive components and OFDMA technology. Moreover, the downstream traffic wavelength is reused for the upstream traffic signal by using re-modulation technology. We report on a successful transmission of 10.7 Gbps OOK upstream and 10.7 Gbps DPSK downstream, together with 1.25 Gbps 16-QAM OFDM VPN traffic, over 20 km no-zero dispersion shifted fiber (NZDSF)

Methylation-mediated silencing of PTPRD induces pulmonary hypertension by promoting pulmonary arterial smooth muscle cell migration via the PDGFRB/PLCγ1 axis

OBJECTIVE: Pulmonary hypertension is a lethal disease characterized by pulmonary vascular remodeling and is mediated by abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). Platelet-derived growth factor BB (PDGF-BB) is the most potent mitogen for PASMCs and is involved in vascular remodeling in pulmonary hypertension development. Therefore, the objective of our study is to identify novel mechanisms underlying vascular remodeling in pulmonary hypertension. METHODS: We explored the effects and mechanisms of PTPRD downregulation in PASMCs and PTPRD knockdown rats in pulmonary hypertension induced by hypoxia. RESULTS: We demonstrated that PTPRD is dramatically downregulated in PDGF-BB-treated PASMCs, pulmonary arteries from pulmonary hypertension rats, and blood and pulmonary arteries from lung specimens of patients with hypoxic pulmonary arterial hypertension (HPAH) and idiopathic PAH (iPAH). Subsequently, we found that PTPRD was downregulated by promoter methylation via DNMT1. Moreover, we found that PTPRD knockdown altered cell morphology and migration in PASMCs via modulating focal adhesion and cell cytoskeleton. We have demonstrated that the increase in cell migration is mediated by the PDGFRB/PLCγ1 pathway. Furthermore, under hypoxic condition, we observed significant pulmonary arterial remodeling and exacerbation of pulmonary hypertension in heterozygous PTPRD knock-out rats compared with the wild-type group. We also demonstrated that HET group treated with chronic hypoxia have higher expression and activity of PLCγ1 in the pulmonary arteries compared with wild-type group. CONCLUSION: We propose that PTPRD likely plays an important role in the process of pulmonary vascular remodeling and development of pulmonary hypertension in vivo

2x2 MIMO-OFDM Gigabit fiber-wireless access system based on polarization division multiplexed WDM-PON

We propose a spectral efficient radio over wavelength division multiplexed passive optical network (WDM-PON) system by combining optical polarization division multiplexing (PDM) and wireless multiple input multiple output (MIMO) spatial multiplexing techniques. In our experiment, a training-based zero forcing (ZF) channel estimation algorithm is designed to compensate the polarization rotation and wireless multipath fading. A 797 Mb/s net data rate QPSK-OFDM signal with error free ( We propose a spectral efficient radio over wavelength division multiplexed passive optical network (WDM-PON) system by combining optical polarization division multiplexing (PDM) and wireless multiple input multiple output (MIMO) spatial multiplexing techniques. In our experiment, a training-based zero forcing (ZF) channel estimation algorithm is designed to compensate the polarization rotation and wireless multipath fading. A 797 Mb/s net data rate QPSK-OFDM signal with error free (&lt;1 × 10−5) performance and a 1.59 Gb/s net data rate 16QAM-OFDM signal with BER performance of 1.2 × 10−2 are achieved after transmission of 22.8 km single mode fiber followed by 3 m and 1 m air distances, respectively