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[Display omitted] • M-N-C/MoS 2 heterostructures exhibit good structural stability, excellent electrical conductivity, and improved stiffness. • The anchored Ir-N-C, Rh-N-C, and Co-N-C are identified as eligible bifunctional ORR/OER electrocatalysts. • The optimal binding strength with the oxygenated intermediates endow anchored M-N-C good catalytic performance. The development of highly-efficient bifunctional oxygen electrocatalysts is essential to the large-scale commercialization of energy-related conversion and storage technologies. In this work, using first-principle computations, we systematically investigated the catalytic activities of a variety of metal-N-C/MoS 2 heterostructures (M-N-C/MoS 2 , M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Os, Ir, and Pt) towards the oxygen reduction/evolution reactions (ORR/OER). Our result revealed that these M-N-C/MoS 2 heterostructures exhibit good structural stability, excellent electrical conductivity, and improved stiffness. Furthermore, the anchored Ir-N-C was identified as the best bifunctional ORR/OER electrocatalyst due to its lowest overpotentials (0.28/0.38 V) among all candidates, which were well rationalized by its optimal binding strength with the oxygenated intermediates. Thus, by combining M-N-C and MoS 2 monolayer, the highly-efficient bifunctional ORR/OER electrocatalysts can be achieved, which offers a new strategy to further explore heterostructures-based materials for other electrochemical processes. [ABSTRACT FROM AUTHOR]

Image segmentation is an essential step in medical image analysis, as its results directly affect the quality of the follow-up analysis. Because of the high calculation speed and the good performance of the segmentation algorithms based on neural networks (NNs), image segmentation has been extensively researched and developed in clinical analysis and applications. However, the existing NN-based image segmentation methods only consider the pixel information of the image that needs to be segmented, and they cannot guarantee the continuity and smoothness of the segmented edge. Consequently, we propose the model and data-driven hybrid approach, namely, the model-data-driven hybrid-fusion network for medical image segmentation. We consider the attention mechanism and the high-low features, and embed the traditional curvature regularisation segmentation model into the NN in the form of a loss function. Moreover, our model considers not only the semantic information of the segmented image but also the boundary length information of the ROI and the target region information. These can ensure the smoothness of the edge of the medical image segmentation results. We conduct intensive experiments on several benchmark datasets to evaluate the effectiveness of our method in dealing with complex backgrounds and noise. Experimental results demonstrate that the proposed model outperforms other state-of-the-art segmentation methods. • We propose a loss function that combines contour length and region information and adds an elastic energy term to it, which tackles the problem of the unsmooth borders caused by purely network training. • We introduce a curvature based regularization function into the segmentation model to regularize the contour length term and improve the over-fitting phenomenon in network training. • We use a new network of a dual-path feature extraction module (DP-FEM) with channel attention and a high-level and low-level feature fusion module (HLFFM) with spatial attention, which improves the accuracy of training. • The results of the proposed fusion network segmentation are analysed with multiple existing models. The results prove that our proposed model can obtain reasonable image segmentation results on datasets, such as remote projection and fundus colour images. [ABSTRACT FROM AUTHOR]

Channeled spectropolarimetry is a snapshot scheme for the full polarization spectra measurement. It has the advantages of static, compact, lightweight, and easy to implement. However, while the broadband polarization spectra can be precisely reconstructed using the regular methods, such as the method based on the Fourier transform, the reconstruction of narrowband polarization spectra always suffers from errors caused by the crosstalk among channels in the optical path difference domain. We present an efficient narrowband full polarization spectra reconstruction method for channeled spectropolarimetry. The line shape of the intensity spectrum is estimated by the envelop curve of the measured high frequency modulated spectrum. The full polarization spectra can be reconstructed by the least-square method under the assumption that polarization states change slowly with wavelength for narrowband polarization spectra. The feasibility of the reconstruction method has been verified by the simulation and experimental results. [ABSTRACT FROM AUTHOR]

• We propose a scheme to measure spectrum, image, and full polarization of targets using polarization modulation array, which offers us a novel method for polarization modulation-demodulation. • The principle and the detection mode of the scheme has been demonstrated. It has no slit and internal moving elements, which makes the system high throughput, robust and compact. • The feasibility of the system has been verified by simulation and experiment. The systematic errors and the sensitivity to noise of the system has been analyzed. • With specified optical designs, this system can be applied in many fields such as remote sensing, biomedical diagnosis, and target identification. In this paper, we propose an instrument concept based on a polarization modulation array for the simultaneous measurement of the irradiance, spectrum, and polarization states of the target of interest. Using a group of retarders and polarizers oriented in specific directions, the full set of Stokes parameters can be determined directly without internal moving parts or extensive calculations. The polarization array consists of two retarders and four linear polarizers located at the incident aperture, so that the incident light is divided into four separate modulation channels. To measure the modulated spectra, we include an interference spectrometer based on the Savart polariscope principle in the system and retrieve the polarization spectra by Fourier transform. We apply a tempo-spatially modulation mode in the scheme to extract the multi-dimensional data of each point in the field of view. The system's performance, especially the capability for Stokes spectra measurement, is verified through both computer simulation and laboratory experiments. Possible sources of error are also analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcined Ge-UTL encountered structural degradation under pure water solution at RT. • A simply ultrasonic treatment caused random arrangement of the formed cfi layers. • The stacking faults of cfi layers generated abundant intracrystal mesopores. • An excellent styrene epoxidation activity (TOF = 403 h−1) is achieved on Co-Meso-UTL. Co-zeolites with hierarchical porous are significantly desirable for the liquid-phase selective epoxidation of styrene that required relatively open reaction spaces. A typical UTL germanosilicate with the absence of organic structure-directing agent molecules inside pore channels suffered from severe structural collapse after ultrasonic treatment under pure water medium, originating from the unstable germanium-rich double four ring subunits. The simple strategy cleaved the weak linkage Ge-O bands and caused the irregular location of silicon-rich cfi layers. Subsequently, Co activity centers was incorporated into the framework through reacting with the abundant silanol groups located in the hydroxyl nests at room temperature. The random arrangement of mono- or multi- cfi layers induced the stacking faults and generated a large amount of intracrystal mesopores after calcination. The resultant Co-Meso-UTL catalysts favored the molecules diffusion of large-sized styrene and target products, improving the accessibility of Co active sites and exhibiting excellent catalytic performance in the styrene epoxidation reaction with single hydrogen peroxide (H 2 O 2) oxidant. Especially, high styrene oxide product selectivity was also obtained through controlling appropriate H 2 O 2 -added content as well as reaction time, which possessed a highest turnover frequency value of 403 h−1 among the reported catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcined *CTH experienced structural collapse and reconstruction by HNO3 treatment. • Sn-*CTH were post-synthesized via the structural rearrangement and Sn incorporation. • Sn-*CTH exhibited a high catalytic activity in the Baeyer-Villiger oxidation. • High ε-caprolactone selectivity was obtained through controlling reaction parameters. Germanium-rich *CTH zeolite without organic molecules located inside pore channels experienced only partial structural collapse and subsequently repaired to high-silica structure analogous to the original topology in a short time. The surprise acid-hydrolysis process has caused a large amount of framework Ge ions were removed, giving rise to abundant hydroxyl nests. Benefiting from the unexpected variation of framework structure and chemical composition, stannosilicates Sn-*CTH with extra-large pores and various Sn loadings (Si/Sn molar ratio in the range of 30-∞) were post-prepared depending on the reaction between the added (NH 4) 2 SnCl 6 species and the formed silanol groups in the hydroxyl nests. The resultant Sn-*CTH zeolites were able to release significantly the diffusion limitations encountered by the bulky substrates and oxidants, exhibiting promising activities to catalyze the Baeyer-Villiger (B-V) oxidation of ketones with single oxidant either hydrogen peroxide (H 2 O 2) or large-sized tert-butyl hydroperoxide (TBHP). Especially, high ε-caprolactone product selectivity was also obtained in the B-V oxidation of cyclohexanone using H 2 O 2 oxidant through reducing the H 2 O 2 /cyclohexanone molar ratio as well as controlling appropriate reaction time, which was more efficient than the traditional Sn-Beta-F catalyst. [ABSTRACT FROM AUTHOR]

The effect of the ratio of two retarders for the demodulation in the intensity modulation spectropolarimeter is proposed. The five-channel autocorrelation function is introduced for the first time, its forming conditions and the principle of spectrum reconstruction are analyzed. From the analysis of the spectropolarimeter based on the interference spectrometer, we can conclude that the spectral resolution of some Stokes parameters reconstructed by the five-channel interferogram is improved compared with the seven-channel interferogram. The simulation experiment of spectrum recovery of five-channel autocorrelation function is carried out. The simulation results are in good agreement with the theory, and the results show that the scheme of the five-channel is feasible, which provides a good theoretical basis and reference for the optimization design of the spectropolarimeter. [ABSTRACT FROM AUTHOR]

The basic principle of Fourier-transform imaging spectrometer (FTIS) based on Savart interferometer is outlined. The un-identical distribution of the optical path difference which leads to the wavelength drift of each row of the interferogram is analyzed. Two typical methods for wavelength calibration of the presented system are described. The first method unifies different spectral intervals and maximum spectral frequencies of each row by a reference monochromatic light with known wavelength, and the dispersion compensation of Savart interferometer is also involved. The second approach is based on the least square fitting which builds the functional relation between recovered wavelength, row number and calibrated wavelength by concise equations. The effectiveness of the two methods is experimentally demonstrated with monochromatic lights and mixed light source across the detecting band of the system, and the results indicate that the first method has higher precision and the mean root-mean-square error of the recovered wavelengths is significantly reduced from 19.896 nm to 1.353 nm, while the second method is more convenient to implement and also has good precision of 2.709 nm. [ABSTRACT FROM AUTHOR]

The theoretical operation and experimental demonstration of a Fourier-transform linear imaging spectropolarimeter are presented. It is composed of a rotating Glan-Taylor prism and a Fourier-transform spectrometer based on Savart polariscope. The polarized light enters the spectrometer to create three sets of interferograms, where the spectral linear Stokes parameters can be calculated and acquired. Compared with previous instruments, the significant advantages of the described sensor are that there are no spatial aliasing in the polarized spectra and it can be used in wider spectral coverage with low cost, ultra-compact size and a simpler common-path configuration. Another static linearly Stokes imaging spectropolarimeter based on the field of view division technique and SPIIS is conceptually described. The spectral dependence of linear Stokes parameters can be recovered with Fourier transformation. Since there is no rotating or moving parts, the system is relatively robust. [ABSTRACT FROM AUTHOR]

The basic principle of channeled Fourier-transform imaging spectropolarimeter (CFTISP) is outlined. The two mainstream techniques existing for performing polarization state demodulation are analyzed, which show uncertainty that may not be suitable for CFTISP based on lateral shear interferometer. A modified demodulation method for Stokes parameters is described. The method separate the phase of the sign and the high-order retarders’ retardations from the total phase acquired from the fast Fourier transform of the interferogram, which will not cause the amplitude error from the reference beam. Furthermore, the retardations and the residual phase error in each band introduced by instrument can be seen directly in this method. The effectiveness of this method is experimentally demonstrated with four known input states of polarization, and the results are satisfactory. The RMS error of each Stokes parameters is also presented, which demonstrates that the low spectral signal-to-noise ratio can increase the RMS error by nearly a factor of 2–5 for the individual Stokes parameters. The comparison of reconstructed results by four methods further demonstrates the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The basic principle of the near-infrared static wind imaging interferometer (NIR-SWINDII) is expounded. The instrument can simultaneously detect the atmospheric wind speed, temperature, and ozone concentration in the middle and lower thermosphere (25–110 km). According to the optical transmission principle, the exact expression of the ideal and actual optical throughput of the NIR-SWINDII is obtained. To analyze and discuss the influence of the field of view, wavelength, and refractive index systematically, we select a high refractive index and a low refractive index glass matching schemes according to the "full compensation" principle of the wide-field Michelson interferometer, the simulation of NIR-SWINDII's optical throughput is carried out. For the high refractive index matching scheme, the results show that when the field of view is within 3 degrees, the transmittance of the NIR-SWINDII can reach 23.38%, and the optical throughput of the entire system is about 0.1024 cm2 ⋅ sr. Comparing with the parameters of other instruments, it is found that our instrument's optical throughput performance is comparable to other instruments. This research provides the theoretical basis and practical guidance for the throughput optimization of the NIR-SWINDII. [ABSTRACT FROM AUTHOR]

In this paper, we present a coded aperture snapshot linear-Stokes imaging spectropolarimeter (CASSIS) based on a combination of coded aperture spectral imager and a division-of-focal-plane polarization camera. The CASSIS achieves aperture coding with a digital micromirror device (DMD) first, and then encodes polarization state using the polarization camera. Finally, the camera gets the coded polarization spatio-spectral image at a single snapshot. Linear-Stokes spectral images are estimated with sparsity-constrained optimization from the acquired image. The principle and feasibility are validated with simulations. It is noted that a modest peak-signal-to-noise ratio (PSNR) is recovered with a single snapshot, and higher PSNR is obtained with multiple snapshots. [ABSTRACT FROM AUTHOR]

• Plate-like BaFe 12 O 19 @ZnFe 2 O 4 /MWCNTs nanocomposites were successfully fabricated via a facile method. • MWCNTs formed conductive networks in the ternary hybrids. • The exchange coupling between BaFe 12 O 19 and ZnFe 2 O 4 could widen the absorption band. • RL min reaches to −42.3 dB at 8.2 GHz and −10 dB bandwidth reaches 3.6 GHz. In order to reduce the radiation and interference of electromagnetic waves, rational assembly of dielectric materials and magnetic materials is becoming a promising strategy to produce highly efficient microwave absorbers. Herein, a novel kind of ternary nanocomposites, multi-wall carbon nanotubes decorated plate-like BaFe 12 O 19 @ZnFe 2 O 4 (BaFe 12 O 19 @ZnFe 2 O 4 /MWCNTs), was fabricated via a two-step method. Plate-like BaFe 12 O 19 was prepared firstly as a template for the growth of ZnFe 2 O 4 layer, forming a core-shell structure. MWCNTs dispersed between BaFe 12 O 19 @ZnFe 2 O 4 particles and ZnFe 2 O 4 microspheres, forming three-dimensional (3D) conductive networks. The careful design of the structure and the combination of the dielectric material with the hard-soft magnetic material caused excellent impedance matching and multiple loss mechanisms, which endow the ternary hybrids with remarkable microwave absorption performance. The minimum reflection loss reaches −42.3 dB at 8.2 GHz with a layer thickness of 2.5 mm, and the effective bandwidth is 3.6 GHz (from 12.5 GHz to 16.1 GHz) with a layer thickness of 1.5 mm. [ABSTRACT FROM AUTHOR]

Highlights • Highly porous carbon decorated with Co nanoparticles were synthesized. • The rambutan-like composites exhibite excellent microwave absorption property. • The pyrolysis temperature is the main factor for the composites. Abstract Nanoporous carbon (NPC) composites embedded with magnetic nanoparticles have been widely studied for applications in microwave absorption. Herein, highly porous rambutan-like carbon composites decorated with controllable carbon nanotubes (CNTs) and Co nanoparticles were synthesized through a thermal decomposition of Co-doped zeolitic imidazolate frameworks-8 (ZIF-8) under different temperatures. The MOF-derived carbon nanocomposites with the cobalt content accounting for 30% of the total mass of cobalt and zinc, carbonized at 700 °C, exhibited excellent microwave absorption property of −30.2 dB. Characterizations exhibit that the in-situ generated Co nanoparticles are uniformly embedded into NPC matrix, which are surrounded by highly graphitized CNTs. The research presents a facile and promising route for rapid mass production of metal-doped NPC/CNTs composites for high-efficiency microwave absorption. [ABSTRACT FROM AUTHOR]

This article investigated the interaction mechanism between carbon monoxide (CO) and lignite organic matter in lignite liquefaction systems. The study found that a CO atmosphere can facilitate lignite conversion, but its hydrogen supply capacity is poor, resulting in lower liquefaction effects compared to an H 2 atmosphere. Increasing the initial reaction pressure and CO content can enhance the conversion of lignite to low molecular compounds. In-situ studies on lignite pyrolysis in CO and N 2 atmospheres show that CO plays an effective role in promoting the fracture of multiple hydrogen bonds present in lignite, which is linked to the water-gas shift reaction that CO takes part. Additionally, CO can also facilitate the breaking of oxygen-containing ether bonds in lignite, thereby eliminating oxygen and producing CO 2 in the gaseous phase. Density functional theory (DFT) calculations demonstrate that CO reacts with the group after the ether bond breaks, which reduces the formation energy of the product and promotes the ether bond breaking. In summary, CO in syngas may benefit the breaking of ether and hydrogen bonds in lignite during liquefaction, thus promoting lignite conversion. [Display omitted] • The interaction mechanism between CO and lignite organic matter in liquefaction was studied. • CO in syngas may be beneficial to the breaking of ether bond and hydrogen bond in lignite. • CO can promote the conversion of lignite to low molecular compounds during liquefaction. [ABSTRACT FROM AUTHOR]

In a static wind imaging Michelson interferometer (SWIMI) developed by us, two-arm glasses are used to achieve the achromatic thermally compensation. The arm glass is cemented with the beam splitter. The tilt of the arm glass would cause a change to the optical path difference (OPD), thereby reducing the visibility of the interferogram and introducing phase error to the SWIMI system, which eventually responsible for errors in the inversion of temperature and wind velocity. In this paper, we present the principle of static wind imaging interferometer and derivate the variation of OPD caused by the two-dimensional tilt of arm glass in detail. By considering a rectangle incident beam, we analyze the effect of arm glass tilt on wind speed and temperature inversion. The results show that in order to realize the wind velocity error less than 3 m/s, the temperature error less than 3 K, and the instrument visibility greater than 0.8, the two-dimensional tilted angle of arm glass should be less than 1". The tolerance of tilted angle can expand by adjusting the refractive index of the medium on both two sides of the arm glass or by adjusting the reflector mirror of the interferometer precisely. The results would be helpful for the cement of arm glass, beam splitter of SWIMI, and provide a reference for the design of a field-widened wind imaging interferometer. [ABSTRACT FROM AUTHOR]

A tempo-spatially mixed modulation Fourier transform imaging spectropolarimeter based on polarization modulation array (PMAFTISP) without internal moving parts was presented, which can obtain the image, spectrum, and full-stokes parameters of the target at the same time. The principle and feasibility were validated with simulations. The system was simulated and the influence of retarder error on the recovery of the full-Stokes parameters was mainly analyzed. Compared with channeled interference imaging spectropolarimetry (CIISP), the system separated four fringe patterns in space, without channel crosstalk as well as simplifying the data processing. Additionally, the advantages of the Fourier transform spectrometer are maintained, such as high throughput (Jacquinot) and multiplex (Fellgett) advantages. [ABSTRACT FROM AUTHOR]