In order to correct the monitoring data of the miniature air quality detector, an air quality prediction model fusing Principal Component Regression (PCR), Support Vector Regression (SVR) machine, ...and Autoregressive Moving Average (ARMA) model was proposed to improve the prediction accuracy of the six types of pollutants in the air. First, the main information of factors affecting air quality is extracted by principal component analysis, and then principal component regression is used to give the predicted values of six types of pollutants. Second, the support vector regression machine is used to regress the predicted value of principal component regression and various influencing factors. Finally, the autoregressive moving average model is used to correct the residual items, and finally the predicted values of six types of pollutants are obtained. The experimental results showed that the proposed combination prediction model of PCR-SVR-ARMA had a better prediction effect than the artificial neural network, the standard support vector regression machine, the principal component regression, and PCR-SVR method. The Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and relative Mean Absolute Percent Error (MAPE) are used as evaluation indicators to evaluate the PCR-SVR-ARMA model. This model can increase the accuracy of self-built points by 72.6% to 93.2%, and the model has excellent prediction effects in the training set and detection set, indicating that the model has good generalization ability. This model can play an active role scientific arrangement and promotion of miniature air quality detectors and grid-based monitoring of the concentration of various pollutants.
In this paper, high-performance bottom-gate thin-film transistors (TFTs) with transparent zinc oxide (ZnO) channels have been developed. The ZnO film for active channels was deposited by RF magnetron ...sputtering. The crystallinity of the ZnO film drastically improved when it was deposited on a doublelayer SiO x /SiN x gate insulator. In order to achieve a ZnO TFT back-plane for liquid-crystal display (LCD) with the required pattern accuracy, dry etching of the ZnO film in an Ar and CH 4 chemistry has been developed. The etching rate and tapered profile of the ZnO film could be controlled by the Ar content in the etching gases of Ar and CH 4 . The saturation mobility (mu sat ) of the ZnO TFT strongly depended on a gate voltage. A mu sat of 5.2 & cm 2 .(V .s) -1 at V GS = 40 V and V DS = 10 V, and an on/off-current ratio of 2.7 x 10 7 were obtained. A drain-current uniformity of plusmn7% was achieved within a radius of 20 mm from the substrate center. A 1.46 -in diagonal LCD with 61 600 pixels has been driven by the ZnO-TFT back-plane. A moving picture image was available on fabricated LCD driven by the ZnO TFTs.
Anatase TiO2 films fabricated by a novel mist chemical vapor deposition method work as efficient photocatalyst.
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•The novel mist CVD method was applied to deposit pure anatase phase ...TiO2 thin films.•The ratio of water-to-methanol was investigated during the deposition.•The growth of {001} facets of TiO2 thin films were dependent on the water-to-methanol ratio.•The enhanced photodegradation of methyl red was obtained from the TiO2 films synthesized with solvent of pure methanol.
The mist chemical vapor deposition method was used to synthesize pure anatase phase titanium dioxide thin films on glass substrates. The effects of water-to-methanol ratio on the structural, optical and photocatalytic properties of titanium dioxide thin films were investigated. Titanium dioxide films deposited by mist chemical vapor deposition were always anatase phase independent of the various water-to-methanol ratios investigated. From the GIXRD results, it was found that with the decrease of the water-to-methanol ratio, the growth of {001} facets was enhanced. The uniformity of the synthesized titanium dioxide thin films was characterized by field emission scanning electron microscopy and atomic force microscope. The highest surface roughness and surface area was obtained with a water-to-methanol of 0 %, corresponding to undiluted 100 % methanol. The transmittance of all anatase titanium dioxide films was higher than 70 % in the visible region. By decreasing the water-to-methanol ratio, the photocatalytic efficiency of the anatase titanium dioxide films exhibited an increasing trend. Due to the highest ratio of {001} facets and maximized surface area, the titanium dioxide films deposited with a water-to-methanol of 0 % have the optimum photocatalytic efficiency, with a high potential for photocatalyst applications.
Pure anatase-phase titanium dioxide films stable up to high temperatures were successfully fabricated by the mist chemical vapor deposition method. A post-annealing treatment of the synthesized films ...was carried out in oxygen atmosphere in the temperature range from 600 to 1100 °C and no anatase to rutile transformation was observed up to 1000 °C. Based on the grazing incidence X-ray diffraction data, the average crystallite size of the titanium dioxide films increased gradually with increasing annealing temperature. The structural analysis revealed that the high thermal stability of the anatase phase can be attributed to the small crystallite size and a sheet-like grain structure. An incomplete anatase to rutile transformation was observed after annealing at 1100 °C.
The uplift processes of the Qinghai–Tibetan Plateau is of great significance for understanding the tectonic dynamics and monsoons in East Asia. In this study, the spatiotemporal characteristics of ...the tectonic uplift along the northeastern margin of the Qinghai–Tibetan Plateau are discussed from a basin–orogen coupling perspective on the basis of detailed analyses of stratigraphy and sedimentology of the Qaidam Basin and comparisons with those of the Xining, Lanzhou, Linxia, Guide–Xunhua, and Jiuquan basins. The asynchronous tectonosedimentary events characterized by alluvial conglomerates at the Early Jurassic–Cretaceous, ~53 Ma, ~40 Ma, ~22 Ma, ~15 Ma, and <2.5 Ma have been preserved in wells at different locations. Consistently, the deposition rates indicate three episodes of accelerated deposition at ~40 Ma, ~20 Ma, and ≤5 Ma in the Cenozoic. Therefore, we believe that the orogenic uplift along the northeastern margin of the Qinghai–Tibetan Plateau can be divided into four stages: Jurassic–Cretaceous, ~40–20 Ma, ~20–5 Ma, and <5 Ma. During the Jurassic–Cretaceous, tectonic activation and uplift occurred in the ancient Qilian orogenic belt, which formed in the Early Paleozoic. By ~40 Ma, the deformation due to the growth of the “proto-Tibetan Plateau” had propagated to the Qiman Tagh Shan–East Kunlun Shan–Ela Shan–West Qinling Mountain chain. Controlled by the tectonic thrusting of the eastern Kunlun Mountains, the Qaidam Basin entered a stage of comprehensive development. At ~20 Ma, the deformation front of the Qinghai–Tibetan Plateau reached the Qilian Shan. The unified Paleogene compressional basin in the northern West Qinling Mountains split into secondary basins, such as the Xining, Lanzhou, Linxia, Guide–Xunhua, and Gonghe basins, which evolved independently. At ~5 Ma, the entire Qinghai–Tibetan Plateau entered a rapid uplift stage, and the large lacustrine basins in and around the plateau shrank and disappeared.
•Sedimentology of drilling wells in the Qaidam Basin is detailed analyzed.•Basin-orogen coupling process was analyzed around the Qaidam Basin.•Four tectonic stages were identified along northeast Qinghai–Tibetan Plateau.
Metamaterials have attracted much attention due to their subwavelength characteristics, especially in the field of unlabeled refractive index sensing. Because biomolecular molecules have special ...biological fingerprint spectra in terahertz band, high sensitivity sensor components can be realized by using the special electromagnetic response of metamaterials. In this paper, a novel biosensor based on electromagnetic induced reflection is designed. We find that the asymmetrically fractured double-ring resonator can effectively enhance the fano-resonance of electromagnetic induction reflection, where the resonance position occurs at 1.57 THz. Oscillating Lorentz model shows that when the resonant detuning continues to increase, the bright mode and the dark mode are strongly coupled. When the light mode decreases, the radiation loss also decreases, which induces the decrease of resonance ability. The sensitivity of pure ethanol solution (analyte) under 5μm coating thickness is 103.7 GHz/RIU, 107.1 GHz/RIU and 112.05 GHz/RIU, respectively. The sensitivity and full width at half maximum (FWHM) of the sensor are studied from the perspectives of analyte concentration, thickness, and proportion, respectively. The results show the great potential of electromagnetic metamaterials as sensitive sensors in biological solution detection.
•We design a new biosensor with asymmetric double-ring resonator to realize the electromagnetic induced resonance.•The mechanism of EIR-like phenomena is explained by the Lorentz model, in which the light mode and the dark mode generate coupling interference.•We evaluate the performance of the proposed refractive index sensor. The sensitivity of pure ethanol solution is 103.7 GHz/RIU, 107.1 GHz/RIU and 112.05 GHz/RIU, respectively.•This work shows the great potential of metamaterials as sensitive sensors in biological solution detection.
Zinc oxide nanorods were grown on an aluminum-doped zinc oxide seeds layer using the chemical bath deposition method. The effects of growth reaction time on the structural, optical, and ...photocatalytic properties of zinc oxide nanorods were investigated. It was clearly observed that the growth direction of zinc oxide nanorods were dependent on the crystallinity of the as-deposited aluminum-doped zinc oxide seed layer. The crystallinity of the obtained zinc oxide nanorods was improved with the increase in reaction times during the chemical bath deposition process. The mechanism of zinc oxide nanorod growth revealed that the growth rate of nanorods was influenced by the reaction times. With increasing reaction times, there were much more formed zinc oxide crystalline stacked growth along the c-axis orientation resulting in an increase in the length of nanorods. The longest nanorods and the high crystallinity were obtained from the zinc oxide nanorods grown within 5 h. The optical transmittance of all zinc oxide nanorods was greater than 70% in the visible region. Zinc oxide nanorods grown for 5 h showed the highest degradation efficiency of methyl red under ultraviolet light and had a high first-order degradation rate of 0.0051 min
. The photocatalytic mechanism was revealed as well.
There has been little investigation for the automatic extraction of power lines from aerial images due to the low resolution of aerial images in the past decades. With increasing aerial ...photogrammetric technology and sensor technology, it is possible for photogrammetrists to monitor the status of power lines. This letter analyzes the property of imaged power lines and presents an algorithm to automatically extract the power line from aerial images acquired by an aerial digital camera onboard a helicopter. This algorithm first uses a Radon transform to extract line segments of the power line, then uses the grouping method to link each segment, and finally applies the Kalman filter technology to connect the segments into an entire line. We compared our algorithm with the line mask detector method and the ratio line detector, and evaluated their performances. The experimental results demonstrated that our algorithm can successfully extract the power lines from aerial images regardless of background complexity. This presented method has successfully been applied in China National 863 project for power line surveillance, 3-D reconstruction, and modeling.
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