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In this study, the effect of annealing atmosphere on the electrical properties, optical properties, microstructure and defects of ZnO∶Al films was investigated in detail. The crystallization, surface and fracture morphologies, electrical properties, resistivity, transmittance, Raman vibration and photoluminescence of ZnO∶Al films were characterized by SEM, XRD, Hall effect test instruments, ultraviolet-visible spectrophotometer, Raman spectra and PL spectra. The results show that after annealing in air atmosphere, the carrier concentration of AZO films decreases from 1.63 × 1020 cm−3 to 7.1 × 1018 cm−3, the optical band gap varies from 3.51 eV to 3.37 eV, the transmittance in NIR increased and the band edge emission in PL spectrum shifted from 3.49 eV to 3.34 eV. On the other hand, while the carrier concentration of AZO films annealing in H2 atmosphere was 5.3 × 1020 cm-3, the optical band gap increases to 3.78 eV, the transmittance in NIR decreases remarkably, the emission intensity of the band edge increases by more than 10 times and the band edge emission in PL spectrum shifts to 3.57 eV. Furthermore, the 4 order LO phonons are observed in ZnO:Al films annealed in air.

A graph is a widely used and effective data structure in many applications; it describes the relationships among nodes or entities. Currently, most semi-supervised or unsupervised graph neural network models are trained based on a very basic operation called negative sampling. Usually, the purpose of the learning objective is to maximize the similarity between neighboring nodes while minimizing the similarity between nodes that are not close to each other. Negative sampling can reduce the time complexity by sampling a small fraction of the negative nodes instead of using all of the negative nodes when optimizing the objective. However, sampling of the negative nodes may fail to deliver stable model performance due to the uncertainty in the sampling procedure. To avoid such disadvantages, we provide an efficient Non-Sampling Graph Neural Network (NS-GNN) framework. The main idea is to use all the negative samples when optimizing the learning objective to avoid the sampling process. Of course, directly using all of the negative samples may cause a large increase in the model training time. To mitigate this problem, we rearrange the origin loss function into a linear form and take advantage of meticulous mathematical derivation to reduce the complexity of the loss function. Experiments on benchmark datasets show that our framework can provide better efficiency at the same level of prediction accuracy compared with existing negative sampling-based models. [ABSTRACT FROM AUTHOR]

Noise-interference suppression and data-processing acceleration are crucial to aeroacoustic measurements with phased array in wind tunnels. In this paper, we develop a "multi-window" beamforming algorithm that recursively processes data based on an array-acquisition model. This spatial filtering algorithm is derived from the Kalman filter theory for signal processing. The simulated results show that by using recursive operations, accurate signal estimation is acquired with incoherent and coherent background noise removed in the presence of both channel noise and phase noise. The convergence rate of this recursive algorithm is faster than the existing algorithms. As a result, considerable storage space and computational resources are saved, while testing defects in wind tunnel measurement are revealed and corrected immediately on-site. It has a great potential for real-time localization of sound sources in a noisy environment. [ABSTRACT FROM AUTHOR]

A hybrid multiuser detection (MUD) using code mapping and a wrong code recognition based on relevance vector machine (RVM) for direct sequence ultra wide band (DS-UWB) system is developed to cope with the multiple access interference (MAI) and the computational efficiency. A new MAI suppression mechanism is studied in the following steps: firstly, code mapping, an optimal decision function, is constructed and the output candidate code of the matched filter is mapped to a feature space by the function. In the feature space, simulation results show that the error codes caused by MAI and the single user mapped codes can be classified by a threshold which is related to SNR of the receiver. Then, on the base of code mapping, use RVM to distinguish the wrong codes from the right ones and finally correct them. Compared with the traditional MUD approaches, the proposed method can considerably improve the bit error ratio (BER) performance due to its special MAI suppression mechanism. Simulation results also show that the proposed method can approximately achieve the BER performance of optimal multiuser detection (OMD) and the computational complexity approximately equals the matched filter. Moreover, the proposed method is less sensitive to the number of users. [ABSTRACT FROM AUTHOR]

Zinc-doped indium oxide (IZO) film, as an important transparent conductive oxide, has attracted increasing attention in various scientific and engineering areas. In the present work, discharge-voltage and reactive-oxygen controlled IZO films were grown by magnetron sputtering and studied systematically. The microstructure, element distribution and chemical bonding of IZO films were investigated by X-Ray diffraction (XRD), transmission electron microscope (TEM), Energy Dispersive X-Ray Spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The optical and electrical properties of IZO films were studied by controlled oxygen and discharge voltage. The typical microstructure of IZO films with optimal optical and electric properties has been characterized. High discharge voltage and matched oxygen vacancies could promote the low resistivity of IZO films, which could be determined by the electronic concentration and mobility. • IZO films were grown at room temperature by two strategies of oxygen and discharge voltage. •Oxygen supply promotes the decreases of oxygen vacancies and Zn content. •More oxygen promotes IZO film with higher transparency and larger bandgap. •Both high discharge voltage and matched oxygen content bring IZO film the superior carrier concentration and mobility. [ABSTRACT FROM AUTHOR]