- 标题
- 摘要
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- 实验方案
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A novel spectral-spatial classification technique for multispectral images using extended multi-attribute profiles and sparse autoencoder
摘要： Image classification is a prominent topic and a challenging task in the field of remote sensing. Recently many various classification methods have been proposed for satellite images specifically the frameworks based on spectral-spatial feature extraction techniques. In this paper, a feature extraction strategy of multispectral data is taken into account in order to develop a new classification framework by combining Extended Multi-Attribute Profiles (EMAP) and Sparse Autoencoder (SAE). Extended Multi-Attribute Profiles is employed to extract the spatial information, then it is joined to the original spectral information to describe the spectral-spatial property of the multispectral images. The obtained features are fed into a Sparse Autoencoder as input. Finally, the learned spectral-spatial features are embedded into the Support Vector Machine (SVM) for classification. Experiments are conducted on two multispectral (MS) images such as we construct the ground truth maps of the corresponding images. Our approach based on EMAP and deep learning (DL), proves its huge potential to achieve a high classification accuracy in reasonable running time and outperforms traditional classifiers and others classification approaches.
关键词： Remote sensing,image classification,Extended Multi-Attribute Profiles,spectral-spatial feature extraction,Sparse Autoencoder,Support Vector Machine
更新于2025-09-23 15:21:01
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Effect of Dye Extraction Solvent on the Photovoltaic Performance of Tecoma stans-Sensitized Solar Cells
摘要： The use of natural dyes as photosensitizers has several advantages including their easy extraction and their biodegradable, nontoxic, and environmentally friendly nature, which makes them vital for application in dye-sensitized solar cells (DSSC). In the present work, we study the effects of extraction solvent on the photovoltaic performance of a natural dye sensitizer for TiO2-based DSSC. Extracts of Tecoma stans flowers in two different solvents, ethanol and ethanol–water mixture, were used as the dye sensitizer for extending the spectral sensitivity of TiO2. The optical properties of the dye extracts were studied by their UV–visible absorption spectra. Fourier transform infrared spectra revealed the presence of anchoring groups and coloring pigments, and nuclear magnetic resonance spectroscopy and mass spectrometry were used to characterize the main constituents of the dye extract. The photovoltaic characteristics of these dye extracts coated on TiO2 were investigated by employing them as DSSC photoanodes. With the dye extracted in ethanol and coated on TiO2, an open-circuit voltage (Voc) of 0.293 V, short-circuit photocurrent density (Jsc) of 0.790 mA/cm2, fill factor (FF) of 0.46, and conversion efficiency (g) of 0.13% were obtained, whereas dye extracted in the ethanol–water mixture revealed Voc of 0.285 V, Jsc of 0.735 mA/cm2, FF of 0.37, and g of 0.09%. The photovoltaic performance of the dye extracts in the two cases underlines the greater effectiveness of ethanol as dye extraction solvent.
关键词： natural dye,DSSC,rutin and zeaxanthin,Tecoma stans flower,TiO2,extraction solvent
更新于2025-09-23 15:21:01
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The application of image analysis technology in the extraction of human body feature parameters
摘要： With the improvement of living standards, personalized clothing customization has become a trend of people’s apparel demand. The key factor in personalized clothing customization is a three-dimensional human modeling. With the development of image analysis technology, it is possible to use image analysis technology to extract human characteristics. In this paper, two-dimensional human feature regions and characteristic parameter extraction methods of images are used. The backpropagation neural network (BP neural network) is used to curve the three-dimensional human characteristics, and the neck, chest, waist, and buttocks of 22 subjects are verified. The results show that the use of this method can well achieve the extraction of human characteristic parameters.
关键词： Human characteristics,BP neural network,Image analysis,Feature extraction,Computer-aided design (CAD)
更新于2025-09-23 15:21:01
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Experimental and clinical study of simultaneous dual-wavelength laser action in energetic cataract surgery
摘要： A new technique of energy cataract surgery with the simultaneous use of two wave-length of laser emission acting as high-intensity laser—endodissector (Nd:YAG, wave-length λ = 1.44? μm) and a low-intensity laser—endobiostimulator (He–Ne, wavelength λ = 0.632? μm) is represented. The surgical technique is bimanual. The radiation of high-intensity laser ensures the destruction of cataract lens of any density level without addi-tional assistance of ultrasound and without manual fragmentation. The laser tip, which contacts the eye tissues, does not heat up. In the process of high-intensity laser action split-ting and spalling of the eye lens core occurs. Laser energy does not go beyond the lens capsule as it is almost completely absorbed by the liquid of the anterior chamber (water) at less than 1?mm from the distal end of the laser tip. Simultaneous exposure to radiation of high-intensity and low-intensity lasers delivered to the eye lens via one laser tip provide to prevent the progression of posttraumatic inflammatory process in the eye at the initial stage of the start of pathophysiological intracellular changes. This ensures high efficiency and safety of simultaneous dual-wavelength laser cataract extraction (DW LCE).
关键词： 0.632?μm He–Ne laser,Phacoemulsification,1.44?μm Nd:YAG laser,Dual-wavelength laser cataract extraction,Intraoperative endoocular bio-stimulation
更新于2025-09-23 15:21:01
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Holographic Fabrication and Optical Property of Graded Photonic Super-Crystals with a Rectangular Unit Super-Cell
摘要： Recently developed graded photonic super-crystals show an enhanced light absorption and light extraction efficiency if they are integrated with a solar cell and an organic light emitting device, respectively. In this paper, we present the holographic fabrication of a graded photonic super-crystal with a rectangular unit super-cell. The spatial light modulator-based pixel-by-pixel phase engineering of the incident laser beam provides a high resolution phase pattern for interference lithography. This also provides a flexible design for the graded photonic super-crystals with a different ratio of length over the width of the rectangular unit super-cell. The light extraction efficiency is simulated for the organic light emitting device, where the cathode is patterned with the graded photonic super-crystal. The high extraction efficiency is maintained for different exposure thresholds during the interference lithography. The desired polarization effects are observed for certain exposure thresholds. The extraction efficiency reaches as high as 75% in the glass substrate.
关键词： spatial light modulator,holographic lithography,organic light emitting device,photonic crystals,graded photonic super-crystals,extraction efficiency
更新于2025-09-23 15:21:01
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Building Extraction from High-Resolution Remotely Sensed Imagery Based on Multi-subgraph Matching
摘要： Building extraction is still a dif?cult issue in the ?eld of remote sensing. In order to extract the buildings with similar structures ef?ciently, an algorithm based on multi-subgraph matching is proposed using only the panchromatic high-resolution remotely sensed imagery (RSI). Firstly, scale-invariant feature transform feature is detected within both RSI and building template, and the corresponding graphs are constructed. Then, binary matching rules are de?ned to reconstruct the graphs to reduce the complexity. At last, according to the homogeneity of the building top, disconnected subgraphs are isolated from the reconstructed graphs. To improve the algorithm accuracy, the matched subgraphs are optimized on the basis of the differences in the structure and size. For verifying the validity of the proposed method, nine representatives are chosen from GF-2 images covering Guangzhou, China. Experimental results show that the precision and recall of the proposed method are 97.73% and 87.16%, respectively, and its overall performance F1 is higher than the three other similar methods.
关键词： Building extraction,Remotely sensed imagery,Multi-subgraph matching,Graph segmentation,SIFT
更新于2025-09-23 15:21:01
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Synergistic Cascade Carrier Extraction via Dual Interfacial Positioning of Ambipolar Black Phosphorene for Higha??Efficiency Perovskite Solar Cells
摘要： 2D black phosphorene (BP) carries a stellar set of physical properties such as conveniently tunable bandgap and extremely high ambipolar carrier mobility for optoelectronic devices. Herein, the judicious design and positioning of BP with tailored thickness as dual-functional nanomaterials to concurrently enhance carrier extraction at both electron transport layer/perovskite and perovskite/hole transport layer interfaces for high-efficiency and stable perovskite solar cells is reported. The synergy of favorable band energy alignment and concerted cascade interfacial carrier extraction, rendered by concurrent positioning of BP, delivered a progressively enhanced power conversion efficiency of 19.83% from 16.95% (BP-free). Investigation into interfacial engineering further reveals enhanced light absorption and reduced trap density for improved photovoltaic performance with BP incorporation. This work demonstrates the appealing characteristic of rational implementation of BP as dual-functional transport material for a diversity of optoelectronic devices, including photodetectors, sensors, light-emitting diodes, etc.
关键词： ambipolar carrier mobility,cascade interfacial carrier extraction,black phosphorene,perovskite solar cells,band energy alignment
更新于2025-09-23 15:21:01
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Unraveling the roles of mesoporous TiO2 framework in CH3NH3PbI3 perovskite solar cells; ????-?TiO2????????¨CH3NH3PbI3é??é??????¤aé?3è????μ?±???-????????¨;
摘要： Both of planar and mesoporous architectures prevail for perovskite solar cells (PSCs). However, it is still an open question how the architecture affects the performance of PSCs. The inconsistent results in the references often create confusion. In particular, the specific roles of mesoporous frameworks are yet to be well elaborated and require further clarification. In this study, we carefully compared the properties of perovskite films and the device performances for both architectures to unravel the roles of mesoporous TiO2 frameworks in CH3NH3PbI3 PSCs. The detailed characterizations of structural, microscopic, optical and electrical properties revealed that the presence of mesoporous TiO2 framework contributed to enlarged perovskite crystal sizes, enhanced light harvesting, efficient electron extration and suppressed charge recombination. As a result, compared with the planar device, the mesoporous device yielded an improved power conversion efficiency of 18.18%, coupled with a reduced hystersis. This study reveals the benefits of mesoporous TiO2 framework in PSCs and provides the guidance for the design and optimization of architectures for high-performance devices.
关键词： device architecture,electron transporting layer,electron extraction,CH3NH3PbI3,perovskite solar cells
更新于2025-09-23 15:21:01
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Modeling and parameters extraction of photovoltaic cell and modules using the genetic algorithms with lambert W-function as objective function
摘要： In this paper, a method based on genetic algorithms is proposed for improving the accuracy of solar cell parameters extracted using novel technique. We propose a computational based binary-coded genetic algorithm (GA) to extract the parameters (I0, Iph, n, Rs and Rsh) for a single diode model of solar cell from its current-voltage (I–V) characteristic. The algorithm was implemented using Matlab as a programming tool and validated by applying it to the I–V curve synthesized from the literature using reported values. The characterization, current-voltage data used was generated by simulating a one-diode solar cell model of speci?ed parameters. The new approach is based on formulating I–V equation of solar cell, with Lambert function, the parameter extraction as a search and optimization problem. Compared with other optimization techniques in literatures, the approach proposed for the determination of parameters are in good agreement.
关键词： Photovoltaic solar cell,genetic algorithm,optimization,parameter extraction,Lambert function
更新于2025-09-23 15:21:01
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Combination of sequential cloud point extraction and hydride generation atomic fluorescence spectrometry for preconcentration and determination of inorganic and methyl mercury in water samples
摘要： A sequential cloud point extraction method was established for the determination of trace mercury species in water samples by hydride generation atomic fluorescence spectrometry (HGAFS). The proposed extraction system consisted of two chief steps: isolation of inorganic mercury (Hg2+) by chelating with potassium?iodide and methyl green, and then isolation of methyl mercury (CH3Hg+) by chelating with ammonium pyrrolidinedithiocarbamate. The nonionic surfactant Triton X?114 was chosen as the extractant, while the brominating agent was applied to convert extracted CH3Hg+ into Hg2+. Before HGAFS detection, the two surfactant?rich phases obtained in the sequential process were separately diluted to 3 mL with 5% (v/v) HCl after the addition of antifoam (0.4 mL). The effects of experimental conditions, including pH and concentration of surfactant and chelating agents, on cloud point extraction were optimized. Under the optimum conditions, the limits of detection for Hg2+ and CH3Hg+ were 0.007 and 0.018 μg/L with the enrichment factors of 15.1 and 11.2, respectively. The proposed method was successfully used for the determination of trace Hg2+ and CH3Hg+ in water samples with satisfactory recoveries of 95?104%.
关键词： Hydride generation atomic fluorescence spectrometry,Non?chromatographic mercury speciation,Cloud point extraction
更新于2025-09-23 15:21:01