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The solar cell is key photovoltaic (PV) device that converts light energy into electricity, and its surface defects are the main reason for the decrease in the efficiency of PV systems. Conventional solar cell defect detection methods are often interfered with by cell substrates and are difficult to detect under high reflection, especially the overlap of substrates and defects. A solar cell defect detection method based on Fourier single-pixel imaging (FSI) is proposed to distinguish periodic substrates and defects in reconstruction by projecting illumination patterns with Fourier fringes, in which the removal of substrates reaches 100%. Meanwhile, for the high reflection present on the solar cell surface, the solar cell is directly treated as a single-pixel detector, which is free from interference from ambient light. The experiment adopts the solar cell itself as an imaging device under highly reflective conditions and removes the interference of the cell substrate by a 4-step phase-shifted FSI reconstruction algorithm to achieve the extraction of four types of defects, each of which is located in a different position of the solar cell substrate, at 10%, 50%, and 100% sampling rates. The method described here complements existing solar cell defect detection approaches and may be applied to enhance photovoltaic testers that rely on real-time correlation measurements, with promising applications in chip inspection and medical cell imaging. • Fourier single-pixel imaging(FSI) method for solar cells defect detection. • By using the solar cell as a photodetector(PD) to avoid the interference of high reflections. • Periodic substrate removal by 4-step phase-shift-based FSI reaches 100% in four different types of defects. [ABSTRACT FROM AUTHOR]

Abstract NiFe 2 O 4 (NFO) with different morphologies were successfully synthesized via a facile hydrothermal method of different precipitants. Results showed that the NFO obtained using urea as precipitant (NFO-U) formed a nanosheet shape, while the powders prepared using CH 3 COONa (NFO-C) exhibited a nanoparticle structure. Both of the two NFO showed a good crystallinity. Conclusion was reached through the results of BET and electrochemical tests that layer structure would improve the properties through a larger specific surface area. Encouragingly, the specific capacitance of NFO-U could arrive 240.9 F/g at the current density of 1 A/g. It was worth noting that the cycle performance of NFO-U was excellent, of which the specific capacitance improved to 128% after 2000 cycles. In addition, an asymmetric supercapacitor (ASC) system was constructed utilizing NFO-U as positive electrode while activated carbon (AC) as negative electrode. The two-electrode system showed a good performance with energy density of 10.15 Wh/kg at a power density of 140 W/kg. Therefore, the construction of sheet-like structures greatly improved the electrochemical performance of NiFe 2 O 4 materials. [ABSTRACT FROM AUTHOR]

• The partial S-doping NiFe 2 O 4 was obtained through a facile hydrothermal method. • The d-spacing of NiFe 2 O 4 was expended caused by partial S-doping. • The impact of partial S-doping to NiFe 2 O 4 is exposed by VASP analysis. • The optimal electrode exhibited the highest specific capacitance of 284 F/g. Nickel ferrite exhibits many advantages as electrode materials in the application of supercapacitor, such as high energy capacity and excellent cycle stability. Whereas, compared with identical-metal sulfides, the specific capacitance of NiFe 2 O 4 is still insufficient. Hence, to combine the superiorities of oxides and sulfides, partial sulfur doping NiFe 2 O 4 is obtained through hydrothermal synthesis method. Analyzed by Vienna Ab-initio Simulation Package (VASP) software and high-resolution transmission electron microscopy, the lattice parameters of NiFe 2 O 4 are confirmed to be expanded by introducing sulfur atoms, which is beneficial to electrochemical performances. At a current density of 1 A/g, the specific capacitance of partial sulfur doping NiFe 2 O 4 is calculated to be 284 F/g, higher than that of the original NiFe 2 O 4 of 182.2 F/g. Moreover, a maximum energy density of 21.14 Wh/kg is achieved at a power density of 375 W/kg. This work shows that partial sulfur doping could improve the electrochemical performance of NiFe 2 O 4. To sum up, this work provides an effective way to enhance the poor electrochemical performance of oxides, greatly encouraging the application of oxides in energy storage field. [Display omitted] [ABSTRACT FROM AUTHOR]

In the recent years, MXenes (2D transition metal carbides, carbon nitrides and nitrides) and its precursor MAX phases have been widely investigated in electrochemical research. In this research, we successfully prepared a core-shell structured compound——Ti 3 C 2 @Ti 2 SnC/CNFs (MXene@TSC/C) as an anode material for lithium ion battery via electrospinning method. Results showed that this type of compound has a specific capacity of 288.9 mAh·g−1 at the current density of 0.4 A g−1 after 300 cycles, accompany with a retention rate of capacity of 105.4% in the rate performance test. These performances were benefit from the core-shell structured CNFs and Ti 3 C 2 MXenes. This work supported a novel way to improve the electrochemical property of MXene and MAX phases, which was expected to further explored. [ABSTRACT FROM AUTHOR]

A sol-gel method was employed for the synthesis of new High-entropy boride (HEB) powders, (Hf 0.2 Nb 0.2 Cr 0.2 Ta 0.2 Mo 0.2)B 2 , with nanoscale. The as-synthesized powders were obtained at a relatively low temperature of 1650 °C, and had small average particle size of 62.09 nm. X-ray diffraction confirmed that the (Hf 0.2 Nb 0.2 Cr 0.2 Ta 0.2 Mo 0.2)B 2 powders were hexagonal single-phase without any oxide impurities. In particular, electrochemical performance of the (Hf 0.2 Nb 0.2 Cr 0.2 Ta 0.2 Mo 0.2)B 2 powders with multiphase and high-entropy single phase were investigated using a three-electrode system. The improved electrochemical performance of the HEB powders is realized, with 27% higher in specific capacitance compared to the powders with multiphase. The HEB powders electrode exhibits a high capacitance retention of 97.03% after 5000 cycles. [ABSTRACT FROM AUTHOR]

• This paper proposes an approach that uses single pixel imaging to obtain images with light interference removed for improving OCR recognition rate without image post-processing. • It is the first time that single pixel imaging is proposed to remove light interference for improving the character recognition rate to the best of the authors' knowledge. • When the character recognition rate of the picture obtained by traditional imaging is 0% by adding a serious interference pattern, the counterpart by single pixel imaging is 95.45%. Optical Character Recognition (OCR), which is generally based on figure recognition, is mainly effective for extracting text from pictures. However, it is a challenge to maintain a high recognition rate without being affected by light interference in a complicated environment. To reduce the light interference for improving the OCR recognition rate, this article proposes a method utilizing single-pixel imaging to obtain images without light interference for character recognition. Unlike the traditional CCD/CMOS-based imaging relying on image post-processing to eliminate interference, the method proposed without the need of any image post-processing which is a cumbersome process and often leads to a deterioration in the quality of the obtained images. Theoretical analysis shows that single-pixel imaging can eliminate the light interference in certain conditions completely. The verification experiments demonstrate that single-pixel imaging can only image the target and ignore an introduced highlighted stripe, whereas traditional CCD/CMOS-based imaging can not eliminate the effects of the stripe without image post-processing. Comparison experiments in contrast with the character recognition rate of the picture obtained from traditional imaging demonstrate the counterpart obtained from single-pixel imaging increased from 88.64% to 97.73%. The evaluation index of correlation and image quality illustrates that the picture obtained by single-pixel imaging has a higher correlation with the target picture and better image quality than the counterpart of the picture obtained from traditional imaging. When the character recognition rate of the picture obtained by traditional imaging is 0% by adding a serious interference pattern from a projector, the counterpart by single-pixel imaging is 95.45%. This approach provides a welcome boost to the development of the application of single-pixel imaging in character recognition by reducing the light interference, which provides a potential direction for the development of OCR to obtain higher recognition success rate under a complex environment. [ABSTRACT FROM AUTHOR]

Morphology of transition metal oxide largely affects its electrochemical energy storage properties. This also applies to its composites. In this paper, NiFe 2 O 4 /Graphene nanosheets composites (NFO/GNSs) are successfully prepared by a facile hydrothermal method. NiFe 2 O 4 (NFO) in the sample exhibits a unique nanosheet morphology, vertically arranging on the graphene nanosheets (GNSs). Microscopically, NFO nanosheets interpenetrate on the surface of graphene to form a continuous network structure. The sample exhibits excellent specific capacitance and rate performance. It is worth mentioning that the specific capacitance increases to 140% after 5000 cycles, showing superior cycle stability. This may be due to the conductive network formed by NFO nanosheets and GNSs. Excellent electrochemical performance indicates excellent application prospects of materials in supercapacitor electrodes. Image 1 • Unique NiFe 2 O 4 nanosheets structure with graphene nanosheets was successfully prepared by a hydrothermal method. • NiFe 2 O 4 nanosheets/graphene performed a better specific capacitance, arriving at 464.15 F/g at current density of 1 A/g. • The network structure formed between NiFe 2 O 4 nanosheets and graphene nanosheets provides excellent cycle performance. [ABSTRACT FROM AUTHOR]

Degradation of imaging quality due to noise sources is one of the most essential problems for single-pixel imaging (SPI). This paper presents a method that separates, identifies, and reduces noise from the 1-D signal of the SPI before reconstructing the image. The proposed method raises the quality of the picture significantly, for example, PSNR from 9.14 dB to 30.29 dB and SSIM from 5.55% to 91.99% when SNR is -15 dB in simulation. This method has a strong robustness to a variety of noise types compared to the traditional filtering methods. The experimental results verified the proposed method's feasibility and improved the image's quality from a chaotic state to an acceptable stage. The method proposed in this paper can separate, identify and remove the noise component from the sources in SPI, which may open a branch by removing noise from sources rather than post-processing. • A method to separate, identify, and reduce noise in single-pixel imaging. • Robust to a variety of noise types compared to the traditional filtering methods. • Enhance the imaging quality and expand application of SPI in noisy conditions. [ABSTRACT FROM AUTHOR]

• A deep-hole imaging method by using MMF is proposed. • Wavelet polarization fusion is applied to deep-hole image reconstruction. • The method achieves reconstruction with a maximum spatial resolution of 3.18 lp/mm. Conventional deep hole imaging uses a camera array as the imaging device, with the lens entering the deep hole to obtain spatial light information for reconstruction. The lens often determines the size of the imaging aperture and it is hard to adapt to different sizes of deep holes, especially elongated ones. This paper proposes a method of the multimode fiber(MMF) deep hole imaging based on wavelet polarization fusion, completed with fiber single-pixel imaging(FSPI) and fiber polarization single-pixel imaging(FPSPI). The system completes three different sizes of deep holes imaging, respectively 8mm × 8mm, 5mm × 5mm, 3mm × 3mm. In addition, the information entropy of each 32 pixels image increases 12.26 % and 11.78 % relative to the original image, which is higher than that of 64 pixels images of the same class, with the spatial resolution of 3.18 lp/mm. The proposed deep hole imaging method based MMF is expected to be applied in pipeline sidewall imaging and deep hole 3D imaging. [ABSTRACT FROM AUTHOR]

In this study, Zn 8 B 3 H 3 O 14 nanosheets were synthesized through a one-step coprecipitation process and employed as both a boron source and substrate templates for the fabrication of boron nitride nanosheets (BNNSs), which were synthesized efficiently at low temperatures by the borate nitration method using ammonia as the nitrogen source. The thickness of the synthesized BNNSs ranged from 3 to 10 nm with a flake dimension of about 2.56 μm. The prepared BNNSs using this method realized 98.8% boron source utilization and single batch yields up to gram level. In addition, BNNSs/SiO 2 microwave-transparent composites were prepared to investigate the potential for large-scale applications of the BNNSs produced by using this method. The composites demonstrated a remarkable increase in bending strength and fracture toughness, reaching 122.02 MPa and 2.31 MPa·m1/2, respectively, with the addition of only 0.5 wt% BNNSs. Compared with SiO 2 without BNNSs, the fracture toughness of the composites is increased by 106%. A novel crack plugging strong toughening mechanism of BNNSs is proposed. Simultaneously, the composites exhibit exceptional microwave-transparent properties, with dielectric constants below 4 in the real part and below 0.03 in the imaginary part. Therefore, this study has successfully achieved the low-temperature and efficient synthesis of micron-scale BNNSs, laying the groundwork for their large-scale application. [Display omitted] • Zn 8 B 3 H 3 O 14 nanosheets were used as substrate templates for the synthesis of BNNSs. • BNNSs were synthesized with high efficiency at low temperatures (900 °C). • The single batch yield of BNNSs reached up to the gram level. • The BNNSs/SiO 2 wave-transparent composites with ultrahigh toughness were obtained. • A novel mechanism for strengthening and toughening (BNNSs plugging) is proposed. [ABSTRACT FROM AUTHOR]

Core-shell hierarchical structured composites have demonstrated great advantages in numerous energy storage devices. In particular, structured composites with rationally structural components and controllable morphology are the most effective in enhancing electrochemical properties. In this work, MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC (carbon cloth) core-shell hierarchical structured composites were designed and successfully synthesized via electrospinning followed by a two-step hydrothermal reaction. The Ti 3 SiC 2 /CC nanofibers and core-shell nanoarrays were able to improve the specific capacitance and cycling stability. In the three-electrode system, the specific capacitance of MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC was observed as 1938.2 F/g at a current density of 1 A/g, while the rate capability retention was observed as 81.7% between 1 and 10 A/g. Furthermore, a superior cycling stability was observed following 5000 cycles with a specific capacitance retention rate of 55.4%. Employing MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC as the all solid-state supercapacitor positive electrode exhibited a high energy density of 58.0 W h/kg at the power density of 800 W/kg. Results demonstrate the potential of the MnO 2 @NiCo 2 O 4 @Ti 3 SiC 2 /CC as an electrode material with phenomenal electrochemical properties for supercapacitors. [ABSTRACT FROM AUTHOR]

Abstract Bimetallic carbides with high activity and stability are promising potential materials for energy-storage application. However, the researches about Fe 2 MoC as electrode material on supercapacitors are comparatively weak, and the processing methods of Fe 2 MoC were also relatively few. Herein, a simple hydrothermal method, combining with carbothermic treatment at 900 °C, is explored to fabricate molybdenum iron carbon (Fe 2 MoC) successfully. Chitosan is not only a carbon source, but also a chelating agent to form bimetallic carbide rather than two separated monometallic carbide during the high-temperature treatment. Fe 2 MoC nanoparticles possessing large specific surface, high activity, stability and small resistance were the promising candidate for electrode material. Systematic electrochemical characterizations have verified the Fe 2 MoC (chitosan as carbon source) possesses a specific capacitance (97.7 F/g at a current density of 0.5 A/g), high rate capability (97.0% capacitance retention from 0.5 to 10 A/g) and cycling stability (83.9% capacitance retention after 1000 cycles) in 1 M KOH. In addition, it offers the energy density of 6.74 Wh/kg at a power density of 21 kW/kg. In view of the low-cost and excellent performance, Fe 2 MoC will hold great promise in energy-storage field for supercapacitors. [ABSTRACT FROM AUTHOR]

• We propose a single-pixel superposition compound eye (SPSCE) that deploys a photodetector which has no spatial resolution and imitates the rhabdom in natural organisms to deliver super-resolution imaging signal, which creates a new branch for the compound eyes. • SPSCE has the capacity to improve the imaging resolution two orders of magnitude than the number of ommatidia without subsequent image processing. • SPSCE has the unique super-robust character to capture whole acceptable images even if almost one-third of ommatidia are not working, and obtain images beyond the actual visual field of the target without observing directly. Deep understanding of biological superposition compound eye provides great opportunities in developing imaging systems with features beyond current planar detector array based imaging devices. However, artificial superposition compound eyes are designed on the basis of a planar detector array and that subsequently leads to the complex optical design and degradation of imaging quality inevitably. We propose a single-pixel superposition compound eye (SPSCE), whose imaging resolution has been improved two orders of magnitude than the number of ommatidia without subsequent image processing. SPSCE has the ability to capture the whole acceptable image of objects even if almost one-third of ommatidia at random positions are not working, which makes it possible to operate reliably even in the damaged state. SPSCE has the capacity to image beyond the actual visual field of the target without observing directly. With only one lateral sub-eye working and deviating from the visual field of the target by 20. 41 ∘ , SPSCE obtains the complete and recognizable image of the target independently through the diffuse reflection optical information of the surrounding environment. The unique super-robust character of SPSCE with its super-resolution property contributes to developing anti-interference artificial compound eyes, unlocking the limit toward development of much higher imaging resolution artificial superposition compound eyes. [ABSTRACT FROM AUTHOR]

Bimetallic carbides have aroused wide attention for energy-storage applications recently. In this work, one-dimensional Fe 2 MoC/CNFs (Fe 2 MoC/C nanofibers) are successfully synthesized via a facile electrospinning method for the first time. To obtain the most integrated structure between the Fe 2 MoC nanoparticles and carbon nanofibers, we explore the optimal heating rate during the carbonization treatment. Fe 2 MoC/CNFs exhibits an integrated one-dimensional structure under 800 °C with a heating rate of 5 °C/min. As revealed in the experimental results, Fe 2 MoC/CNFs possesses a high specific surface area of 196.9 m2/g, a high specific capacitance of 347.8 F/g at the current density of 1 A/g, an excellent rate capability of 91% capacitance retention from 1 A/g to 40 A/g, and shows superior cycling stability with the capacitance retention of about 85.6% and Coulombic efficiency of about 100% after 5000 cycles. An asymmetric supercapacitor coin-cell device using Fe 2 MoC/CNFs as the positive electrode displays an energy density of 14.5 Wh/kg at a power density of 300 W/kg and an outstanding cycling life of 93% retention after 5000 cycles. The impressive electrochemical performance indicates that the Fe 2 MoC/CNFs composite is a promising material for efficient supercapacitors. Image 1 • Fe 2 MoC nanofibers can be prepared via a facile electrospinning method. • Fe 2 MoC/CNFs-5 exhibits a superior rate capability and cycle stability. • ASC coin-cell device shows a promising energy and power density. [ABSTRACT FROM AUTHOR]