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Abstract: Crystallization in amorphous Ge2Sb2Te5 films by irradiation with femtosecond laser was investigated. The reflectivity and X-ray diffraction measurements confirmed that the crystalline state has been achieved in amorphous Ge2Sb2Te5 films under the irradiation of femtosecond laser with an average power of 65 mW at a frequency of 1000 Hz and a pulsed width of 120 fs. The surface morphology before and after femtosecond laser irradiation was studied by scanning electron microscope; results showed that the surface of films with irradiation of femtosecond laser was composed of some the crystallized micro-region. [Copyright &y& Elsevier]

Abstract: Crystallization is achieved in amorphous Ge2Sb2Te5 films upon irradiation with a single femtosecond laser pulse. Transmission electron microscopy images evidence the morphology of the crystallized spot which depends on the fluence of the femtosecond laser pulse. Fine crystalline grains are induced at low fluence, and the coarse crystalline grains are obtained at high fluence. At the damage fluence, ablation of the films occurs. [Copyright &y& Elsevier]

Abstract: Structured light 3D vision inspection is a commonly used method for various 3D surface profiling techniques. In this paper, the mathematical model of the structured light stripe vision sensor is established. We propose a flexible new approach to easily determine all primitive parameters of a structured light stripe vision sensor. It is well suited for use without specialized knowledge of 3D geometry. The technique only requires the sensor to observe a planar target shown at a few (at least two) different orientations. Either the sensor or the planar target can be freely moved. The motion need not be known. A novel approach is proposed to generate sufficient non-collinear control points for structured light stripe vision sensor calibration. Real data has been used to test the proposed technique, and very good result has been obtained. Compared with classical techniques, which use expensive equipment such as two or three orthogonal planes, the proposed technique is easy to use and flexible. It advances structured light vision one step from laboratory environments to real engineering 3D metrology applications. [Copyright &y& Elsevier]

Carbon dioxide (CO2) gas analyzer can be widely used in many fields. A novel CO2 gas analyzer based on infrared ray (IR) absorption is presented sufficiently in this paper. Applying Lambert–Beer Law, a novel space-double-beam optical structure is established successfully. The optical structure includes an IR source, a gas cell, a bandpass filter with a transmission wavelength at 4.26 μm, another bandpass filter with a transmission wavelength at 3.9 μm, and two IR detectors. Based on Redial Basic Function (RBF) artificial neural network, the measuring model of IR CO2 analyzer is established with a high accuracy. A dynamic compensation filter is effectively designed to improve the dynamic characteristic of the IR CO2 analyzer without gas pump. The IR CO2 analyzer possesses the advantages of high accuracy and mechanical reliability with small volume, lightweight, and low-power consumption. Therefore, it can be used in such relevant fields as environmental protection, processing control, chemical analysis, medical diagnosis, and space environmental and control systems. [Copyright &y& Elsevier]

Crystallization in amorphous Sb-rich AgInSbTe films was induced by femtosecond laser with an average power 65 mW at a frequency of 1 kHz and a pulsed duration of 120 fs. The reflectivity and X-ray diffraction measurements confirmed the formation of the crystalline state in amorphous Sb-rich AgInSbTe films. Atom force microscopy (AFM) observed the characteristics of the surface morphology of amorphous, annealed and femtosecond laser-induced films. Results indicated the surface of Sb-rich AgInSbTe films induced by femtosecond laser is not smooth and contains many crystalline granules. [Copyright &y& Elsevier]

By using a polyacrylamide (PAAM)-coated silicon carbide (SiC) powder, at pH=5, homogeneous and stable suspensions of proper rheological property and low viscosity, containing 55 vol.% solids, were prepared. Stability, Zeta-potential and the rheological property of suspensions were studied. To further improve the solids content, two sizes of powders were mixed and graded. When 52 wt.% coarse and 48 wt.% PAAM-coated SiC powder were mixed, the solids content of suspensions was 65–70 vol.%, and the suspensions were of proper rheological property, homogeneity and stability. The results showed that rheological property of suspensions containing coarse particles were shear thinning at a low shear rate and thickening at a high shear rate when the solids content was between 60 and 65 vol.%. [Copyright &y& Elsevier]

It is an available way to coat the organic compound on the silicon carbide (SiC) powder surface during the investigation of preparing the highly concentrated SiC suspensions. In the paper, we suggest the technological methods of coating organic compound on the SiC powder surface and provide a new way to confirm the coating technological parameters and then to optimize them. Under the optimized technological parameters, we have obtained the polyacrylamide-coated SiC powder with the better property and prepared the low viscosity, homogeneity and stability suspensions with 50 vol.% solids content. [Copyright &y& Elsevier]

The calibration of camera distortion plays an important role in the field of industrial machine vision application. In this paper, a novel approach for calibrating camera radial distortion is presented based on cross-ratio invariability for perspective projection. Assumed to be with one-order radial distortion, the image coordinates and the cross-ratio of only four collinear points in space are needed in this approach. The cross-ratio, easily known from a calibration target, is identical with that of the four corresponding image points. This is called the cross-ratio invariability for perspective projection. A monadic two-order equation is built based on the cross-ratio invariability, which gives an accurate solution to radial distortion coefficients. A digital simulation and a practical image correction prove this approach to be simple, accurate, efficient and time saving. [Copyright &y& Elsevier]

3D double-vision inspection is very necessary. It has a larger field of view, and can solve the problem of "blind area" for 3D measurement, as proposed by 3D single-vision inspection. At the beginning of this paper, the principle of structured-light based 3D vision inspection is introduced. Then, a method of gaining calibration points for 3D doublevision inspection system is proposed in detail. In order to gain calibration points with high precision, a double-directional photoelectric aiming device is designed as well, and a method for compensating the position-setting error of the aiming device is described. The coordinates of all calibration points are precisely unified in a world coordinate system. The application of RBF (radial basis function) neural network in establishing the inspection model of structured-light based 3D vision is described in detail. Finally, with the use of the calibration points, the inspection model of 3D double-vision based on RBF neural network is successfully established. The model's training accuracy is 0.078 mm, and the testing accuracy is 0.084 mm. [ABSTRACT FROM AUTHOR]

Structured light 3D vision inspection is a commonly used method for various 3D surface profiling techniques. In this paper, a novel approach is proposed to generate the sufficient calibration points with high accuracy for structured light 3D vision. This approach is based on a flexible calibration target, composed of a photo-electrical aiming device and a 3D translation platform. An improved algorithm of back propagation (BP) neural network is also presented, and is successfully applied to the calibration of structured light 3D vision inspection. Finally, using the calibration points and the improved algorithm of BP neural network, the best network structure is established. The training accuracy for the best BP network structure is 0.083 mm, and its testing accuracy is 0.128 mm. [Copyright &y& Elsevier]

Micro-tubular solid oxide fuel cell (MT-SOFC) is considered as a promising choice for portable applications. In this work, we developed a novel metal supported MT-SOFC with porous 430 stainless steel support| 430 stainless steel-SSZ| SSZ| porous SSZ sandwich structure by dip coating and one-step co-sintering technology. The metal supported MT-SOFC showed good connection between each function layer and exhibited a significant maximum power density of 271 mW cm−2 at 800 °C. Although the power density showed about 19.6% off after 14 thermal cycles between 600 °C and 800 °C, and about 5% per 100 h degradation rate during the 200 h long-term stability test at 700 °C and 0.7 V, the structure of the single cell could be maintained well and no crack and Sr diffusion was observed. As the result, the ohmic resistance of the cell kept unchanged during the thermal cycling and long-term test. The relatively fast degradation was attributed to the Ni and LSM particles coarsening and agglomeration, which will be improved in the further work. This work presented a low-cost and simple way to fabricate the metal supported MT-SOFCs with good electrochemical performance. • Metal supported MT-SOFC with sandwich structure is successfully fabricated by dip-coating, co-sintering and impregnation. • The maximum peak power of 271 mW cm−2 is achieved at 800 °C. • The degradation mechanism was analyzed in detail. • The ohmic resistance remained constant after rapid thermal cycling, showing stability of cell structure. [ABSTRACT FROM AUTHOR]

• Considered the temperature rise of MTJ in parallel state and anti-parallel state. • Considered the TDDB model in parallel and anti-parallel states. • Considered self-heating effects in the TDDB model. Spin-transfer torque magnetic random access memory (STT-MRAM) is one of the most promising candidates for "universal memory" with the ultra-fast access speed, radiation resistance and theoretically unlimited endurance. However, there are many practical aspects that could degrade the life-time of STT-MRAM. In this paper, degradation on the life-time of the STT-MTJ device is observed experimentally, which is attributed to the so-called "self-heating effect" of the device. Simulation on the device is conducted on the self-heating effect to obtain the internal temperature inside the device. The self-heating effect of the STT-MTJ device is analyzed and its influence on the life-time degradation of the STT-MTJ is included in the time dependent dielectric breakdown model (TDDB, 1/E model). This inclusion should improve the accuracy of the estimation on the life-time. [ABSTRACT FROM AUTHOR]

Aircraft attitude has always been an important technical parameter during flights, especially for stages such as aircraft take-off and landing. This article presents a monocular off-board vision system for relative attitude measurement of fixed-wing aircraft. In this system, a zoom imaging subsystem is set up to track and shoot the aircraft over a large distance range. Image sequences and corresponding servo data are transmitted to the processing computer for vision algorithms. A model-based attitude tracking algorithm, which requires the computer-aided design model of the aircraft, is performed to measure the relative attitude of the aircraft with respect to the reference platform. A 2-D visual tracking algorithm and a target detection algorithm are also employed to control the vision system. The proposed attitude tracking algorithm achieves competitive results on a publicly available dataset. The full system is validated in a real-flight experiment. The results revealed that the proposed system can run in real time on 1920×1080@40 Hz videos with an accuracy better than 0.5 $^\circ$. [ABSTRACT FROM AUTHOR]

A series of perylene diimide (PDI) derivatives, TPP‐PDI, TPO‐PDI, and TPS‐PDI, are developed for nonfullerene polymer solar cells (NF‐PSCs) by flaking three PDI skeletons around 3D central cores with different configurations and electronic states, such as triphenylphosphine (TPP), triphenylphosphine monoxide (TPO), and triphenylphosphine sulfide (TPS). These small‐molecule acceptors have a "three‐wing propeller" structure due to their similar backbones. By changing the electron density of phosphorus atoms through oxidation and sulfuration, the "folding‐back" strength is decreased, resulting in a less twisted molecular conformation. The stronger electron‐withdrawing ability of the oxygen atom affords TPO‐PDI the least twisted conformation, which enhances the crystallinity of this complex. NF‐PSCs based on PTTEA:TPO‐PDI exhibit a high power conversion efficiency (PCE) of 8.65%. Ultimately, the joint "molecular lock" effect arising from OH⋅⋅⋅F and OH⋅⋅⋅OP supramolecular interactions is achieved by introducing 4,4′‐biphenol as an additive, which successfully promotes fibril‐like phase separation and blend morphology optimization to generate the highest PCE of 11.01%, which is currently the highest value recorded for NF‐PSCs based on PDI acceptors. [ABSTRACT FROM AUTHOR]

Reversible solid oxide fuel cells (RSOCs) are advanced energy conversion and storage devices, allowing for the flexible interconversion of electricity and chemical energy in fuels like hydrogen or syngas. However, the pores structure of RSOCs prepared by conventional methods is not conducive to fuel gas diffusion, resulting in severe concentration polarization. In this work, a novel cell structure with 3 mol% Y 2 O 3 stabilized ZrO 2 (3YSZ) | NiO-Sc 2 O 3 stabilized ZrO 2 (SSZ) bilayer finger-like porous structure with favorable strength is successfully prepared by the phase-inversion tape casting method. The peak power density of the cell is reached 0.97 W cm−2 at 800 °C in the fuel cell (FC) mode and no notable degradation is observed after undergoing 30 thermal cycles at 0.75 V. Furthermore, the cell demonstrates a current density of 1.00 A cm−2 when operated in electrolysis cell (EC) mode with 90% H 2 O at 800 °C and 1.3 V, and no obvious degradation is observed on the cell alternating between FC mode and EC mode alternately for 80 h. These results show the improvement of mechanical strength and mass transfer, and strengthen the application ability of 3YSZ | NiO-SSZ bilayer finger-like porous structure in RSOCs. • The cell with 3YSZ.| NiO-SSZ finger-like porous structure is successfully prepared. • Bilayer structure exhibits excellent mechanical strength and gas diffusion capacity. • The cell shows good thermal stability in FC mode. • No obvious degradation was observed in both FC and EC mode on the cell. [ABSTRACT FROM AUTHOR]

Autonomous aerial refueling (AAR) can improve the aircraft’s combat effectiveness, and drogue visual tracking is one of the key technologies for the success of AAR. Target tracking is challenging as high-speed drogue often undergo abrupt motions, leaving the vision field, and significant hollow background variation over time. To address these challenges, a tracker based on multiparameter adaptive adjustment is proposed. First, we propose a background awareness module to perceive the hollow background of the drogue, which contributes to fully utilize background information. Second, the parameter and feature adaptation module is proposed to optimize the parameters and features by combining the information of drogue motion and the changing background. Finally, the tracking result is determined by the designed adaptive fusion module that conduces to the elevation of the tracking accuracy. The three modules are effectively merged, allowing our system to track the hollow object robustly and leading to superior results on the drogue videos experiment in the sky compared with state-of-the-art trackers. [ABSTRACT FROM AUTHOR]

Two novel perylene diimide (PDI)–based derivatives, Alq3‐PDI and Alq3‐PDI2, are synthesized by flanking a 3D tri(8‐hydroxyquinoline)aluminum(III) (Alq3) core with PDI and a helical PDI dimer (PDI2) to construct high‐performance small molecular nonfullerene acceptors (SMAs). The 3D Alq3 core significantly suppresses the molecular aggregation of the resulting SMAs, leading to a well‐mixed blend with a PTTEA donor polymer and weak phase separation. Compared with Alq3‐PDI, the extended π‐conjugation of Alq3‐PDI2 results in higher‐order molecular packing, which improves the absorption and phase separation behavior. Thus, the Alq3‐PDI2 devices have higher Jsc and FF values and better device performance, which are further enhanced by a small amount of 4,4′‐bipyridine (Bipy) as an additive. The coordination between Bipy and the Alq3 core promotes molecular packing and phase separation, which lower charge recombination and enhanced charge collection in the resulting devices. Therefore, a largely improved Jsc of 15.74 mA cm−2 and very high FF of 71.27% are obtained in the Alq3‐PDI2 devices, resulting in a power conversion efficiency of 9.54%, which is the best value reported for PDI‐based polymer solar cells. The coordination can also serve as a "molecular lock," which prevents molecular motion and thus improves device stability. [ABSTRACT FROM AUTHOR]

The estrogen inhibits colonic smooth muscle contractions, which may lead to constipation. However, the mechanisms of inhibition are poorly understood. Therefore, the present study examined the effect of estrogen on rat colonic smooth muscle contractions and its potential association with the large-conductance Ca2+-activated K+ channels β1 (BKβ1) subunit. Twenty-four female Sprague Dawley rats were randomly assigned to 4 groups. After 2 weeks of intervention, the contraction activity of isolated colonic smooth muscle and the expression of BKβ1 in colonic smooth muscle of rats were detected. Additionally, in order to investigate the effects of estrogen on BKβ1 expression and calcium mobilization, in vitro experiments were conducted using rat and human colonic smooth muscle cells (SMCs). BKβ1 shRNA was used to investigate whether calcium mobilization is affected by BKβ1 in colonic SMCs. To explore the relationship between ERβ and BKβ1, serial deletions, site-directed mutagenesis, a dual-luciferase reporter assay, and chromatin immunoprecipitation assays were employed. In response to E2, colonic smooth muscle strips showed a decrease in tension, while IBTX exposure transiently increased tension. Furthermore, in these muscle tissues, BKβ1 and α-SMA were found to be co-expressed. The E2 group showed significantly higher BKβ1 expression. In cultured colonic SMCs, the expression of BKβ1 was found to increase in the presence of E2 or DPN. E2 treatment reduced Ca2+ concentrations, while BKβ1 shRNA treatment increased Ca2+ concentrations relative to the control. ERβ-initiated BKβ1 expression appears to occur via binding to the BKβ1 promoter. These results indicated that E2 may upregulate BKβ1 expression via ERβ and inhibit colonic smooth muscle contraction through ERβ by directly targeting BKβ1. [ABSTRACT FROM AUTHOR]

Unlike the traditional star pattern recognition algorithms that extract star features as a vector to be matched in a database, in this article, a spider-web image is constructed and a hierarchical convolution neural network (CNN) model is proposed to recognize this spider-web image. Stars are linked with different color lines based on the angle distance to enhance the discrimination of the spider-web images. A training dataset and testing dataset are constructed based on spider-web images for CNN model training. A hierarchical CNN model with two stages, which are designed to perform first step identification and recognize similar spider-web images, respectively, is proposed. Experiment results show that, compared with other algorithms, the proposed algorithm is more robust toward the position noise, magnitude noise, small numbers of stars in the field of view, and the presence of false stars. [ABSTRACT FROM AUTHOR]

The real-time monitoring of wheel size is important technology in ensuring the normal and safe operation of railways. Meanwhile, online dynamic measurement equipment based on structured-light sensors is becoming increasingly available. However, such equipment only has an “artificial” measurement mode, collects minimal data, has low reliability, and cannot be used in an on-site complex environment. In this regard, we propose a measurement system based on multisensor data fusion. When a wheel to be measured passes through a rail, two groups of wheel cross-profile acquisition sensors are arranged. Then, two profiles of the measured wheel are reconstructed, aligned together, and segmentation parameterized for a complete profile. On the one hand, they can compensate each other to overcome the data missing in wheel profile. On the other hand, it improves measurement accuracy by resisting error noise data induces. With the complete wheel cross-profile, the reliable and accurate wheel size parameters are obtained. Furthermore, the feasibility of this method is verified by analyzing possible influencing factors. Real experiments demonstrate the robustness and dynamic measurement accuracy. In conclusion, this measurement system is simple and highly robust for an on-site complex environment and has a promising application value. [ABSTRACT FROM AUTHOR]

A good on-line contact, characterized by high-precision measurement, between the pantograph and catenary (PAC) ensures the safety of PAC and subsequently high-speed train operation. Currently, image processing is the mainstream measurement method for detecting contact points, in which the contact point’s real-time tracking in the image sequences with complex background is the method’s core difficulty. In this paper, a contact point surveillant method that can run during the actual operation of the railway is proposed. This surveillant method can be initialized by the global robust detection method and can do real-time tracking by means of kernelized correlation filters, which has high stability in regional tracking. With the help of result refinement and result confidential evaluation methods, this surveillant method can stably and independently obtain real-time and accurate results, which further gives the state analysis based on 3-D positions. The proposed method is tested on image data sets collected from a high-speed train running at 200 km/h, and results corroborate that a high-speed, high-precision, and stable contact point tracking is achievable, which ensures the state measurement’s feasibility by means of the contact point trajectory. [ABSTRACT FROM AUTHOR]

This study provides an on-board image processing algorithm for a spacecraft optical navigation sensor system. We propose a high-precision planetary center localization algorithm that provides effective information for subsequent spacecraft navigation measurement considering the geometric properties and special texture features of the planetary image. First, we combine a morphological opening with a minimum spanning circle method to preprocess an image. Second, a gradient direction partial area effect method in the edge region of interest is proposed for high-precision subpixel edge extraction. This study combines the law of edge energy distribution with a gradient direction partial area effect on planetary edge detection. A nonlocal filtering method is proposed to improve the results under complex conditions. Finally, the center coordinates of the planet are obtained by fitting the circular arc edges using least squares. The simulated and real images show that our algorithm can obtain high-precision subpixel edges and center coordinates for regular planetary images, with strong robustness to planetary images with noise, complex background, and rich texture. • Image preprocessing extracts the circular arc edges of the planet. • Gradient direction partial area effect can achieve high precision edge extraction. • Nonlocal filtering method improves the results under high noise. [ABSTRACT FROM AUTHOR]

A new two-dimensional phonon crystal structure was designed and studied deeply by finite element method and equivalent model method. It is found that the structure has good low-frequency sound absorption performance. Through theoretical derivation and simulation calculation, it is found that the structure has a complete four band gap within 0 ~ 800 Hz under the condition of lattice constant of 21 mm. The lower limit of the first band gap is as low as 40. 28 Hz, and the bandwidth is approximately 93 Hz. Sound transmission loss calculation shows that the structure has a good acoustic insulation effect in the low frequency domain, and the maximum sound insulation amount can reach 87. 31 dB. After analyzing the multiple vibration modes of the structure, the corresponding equivalent model is established, and the influence of different factors on the band gap is explored based on the equivalent model. The general regularities of the new two-dimensional phonon crystal are summarized. The results show that increasing the scatterer density and reducing the matrix density can increase the bandwidth, and increasing the filling rate and properly opening the scatterer can improve the band gap characteristics. The research may provide some ideas for solving low-frequency noise control problems in engineering application. [ABSTRACT FROM AUTHOR]

Highlights • Local intensity moments are used to estimate the affine distortion. • Affine invariant sampling pattern is proposed for binary descriptor. • Sequence order constrain is utilized to sort matched features into local groups. • Local geometric consistency check is applied in mismatch removal. • The speed, recall, and affine invariant ability are improved. Abstract Robust feature matcher is usually inapplicable to real time computer vision applications as its high computational complexity, while fast feature matcher is short of robustness to geometric transformations. By studying the sampling pattern of binary descriptor and local geometric statistics of features, this paper proposes a fast and robust feature matching method with binary affine invariant descriptor and local geometric consistency check (BALG). The sampling pattern is adaptively adjusted according local affine transformation that can be effectively estimated from the local intensity moments. The affine sampling pattern improves the affine invariance of binary descriptor while enable fast processing. Furthermore, candidate matches are sorted into local groups along different orientations with sequence order constraint, and then followed by local geometric consistency check. False matches are efficiently filtered out with high recall. Extensive experiments on four publicly benchmark datasets prove the proposed method to be an alternative for time critical feature matcher. [ABSTRACT FROM AUTHOR]

Binary descriptors are drawing increasing interest as they enable faster processing in a lower memory footprint, which are suitable to large-scale and real-time vision applications. However, the performance of most existing binary descriptors tends to be inferior to those of the competing floating-point descriptors. In this paper, by considering each bit might contribute differently to the robustness and distinctiveness, a novel binary descriptor based on binary weights learning is proposed, referred to as a robust weighted binary descriptor (RWBD). Technically, each bit of RWBD is built upon difference tests of pairwise complementary information sampling with varying Gaussian kernels, leading to a more informative and robust description. Furthermore, RWBD imposes different emphases on all bits utilizing the learned binary weights, which can significantly improve the discriminative power and preserve the fast matching advantage. Extensive experiments on the publicly challenging benchmarks, including image matching and object recognition data sets, clearly demonstrate the effectiveness and efficiency of the proposed approach. [ABSTRACT FROM AUTHOR]

Robotic wire and arc additive manufacturing (WAAM) systems are required to provide predictable and efficient operations to fabricate solid metallic parts with high morphological fidelity and geometric accuracy. Since the metallic parts are fabricated based on a layer-by-layer principle, the interactions between the neighboring beads and layers strongly influence the geometric accuracy of the fabricated part. The layers-overlapping process has been studied and a traditional layers-overlapping model (T-LOM) has been published in the literature. This paper proposes a layers-overlapping strategy (LOS), based on which a revised layers-overlapping model (R-LOM) was proposed for the fabrication of multi-layer multi-bead (MLMB) components with homogeneous layers. A mathematical model for layers-overlapping is presented, which considers the material shortage areas at the edges of the layers. This is important since the material shortage areas result in a situation that the component width is smaller than the expected value. In addition, they will be accumulated when multiple layers are overlapped through normal unidirectional parallel (NUP) paths. The proposed LOS addresses two aspects: (i) the deposition amount of the first bead and the last bead in the lap layers should be increased and (ii) the deposition position of the first bead and the last bead in the lap layers should be moved towards the edges with a given offset distance. Validation experiments were designed and conducted to test the proposed concepts and models. The experimental results indicated that (i) the R-LOM enables the MLMB components to achieve the expected width and (ii) for components deposited with NUP paths, the R-LOM eliminates the effect of accumulation of material shortage areas on the first bead and increases the surface flatness. [ABSTRACT FROM AUTHOR]

Wire and arc additive manufacturing (WAAM) is a competitive technology for fabricating metallic parts with complex structure and geometry. It enables the fabrication of multi-layer multi-bead (MLMB) parts. The basis of planning the deposition paths is the beads overlapping model (BOM). The existing overlapping models consider only the geometric area of adjacent beads, but ignore the spreading of the melted weld beads. The objective of the research was to develop an enhanced BOM (E.BOM) for WAAM, which takes the spreading of the weld beads into consideration. A deposited bead spreads to the already deposited neighboring bead and as a consequence, its center point deviates from the center point of the fed (to be melted) wire. Experiments were designed to explore the relationships between the geometries of the beads, and the offset distance between the center of a weld bead and the center of the fed wire. An artificial neural network was used to predict the offset distance of a certain weld bead based on the results of the experiments. In addition, a reasoning algorithm was implemented to calculate the optimal distance between the centers of adjacent deposition paths in order to achieve a planned center distance between adjacent beads. This enables the control of the actual center distance of the adjacent beads according to an expected value. The E.BOM has been tested by validation experiments. On the one hand, it improves the surface flatness of layers of MLMB parts produced by WAAM. On the other hand, it prevents formation of defects inside the parts. [ABSTRACT FROM AUTHOR]

For low-frequency noise control problems, a Helmholtz-type phononic crystal with an adjustable chamber was constructed. The inner chamber of the structure is divided into upper and lower chambers by a diaphragm connected by a movable telescopic screw. Meanwhile, an arch-shaped opening channel is adopted. Characteristics of bandgap and sound insulation of the structure are analyzed by finite element method, and equivalent models of the structure at the starting frequency and cut-off frequency of the bandgap are constructed by "acoustic-force analogy" method. The results show that the designed structure can generate six complete bandgaps within 500 Hz, and the lowest bandgap frequency can reach 31. 34 Hz. At the same time, it shows good sound insulation performance in each bandgap frequency band, and the maximum sound insulation is up to 111. 95 dB. Finally, by adjusting the telescopic screw and changing the cavity structure layout, multiple resonant bandgaps can be connected to form a wide bandgap, and achieve the purpose of adjusting the sound insulation band. This design provides a new idea for the sound insulation performance of Helmholtz type phononic crystals. [ABSTRACT FROM AUTHOR]

The oxygen electrode-supported reversible solid oxide cell (RSOC) has demonstrated distinguishing advantages of fuel flexibility, shorter gas diffusion path and more choices for fuel electrode materials. However, there are serious drawbacks including the difficulty of co-firing the oxygen electrode and electrolyte, and the inefficient electrochemical performance. In this study, a (La 0.8 Sr 0.2) 0.95 MnO 3-δ (LSM) supported RSOC with the configuration of La 0.6 Sr 0.4 Fe 0.9 Sc 0.1 O 3-δ (LSFSc)-YSZ/YSZ/CuNi–CeO 2 -YSZ is fabricated by tape casting, co-sintering and impregnation technologies. The single cell is evaluated at both fuel cell (FC) and electrolysis cell (EC) mode. Significant maximum power density of 436.0 and 377 mW cm−2 is obtained at 750 °C in H 2 and CH 4 fuel atmospheres, respectively. At electrolysis voltage of 1.3 V and 50% steam content, current density of −0.718, −0.397, −0.198 and −0.081 A cm−2 is obtained at 750, 700, 650 and 600 °C respectively. Much higher electrolysis performance than FC mode is exhibited probably due to the optimized electrodes with increased triple phase boundary (TPB) area and faster gas diffusion (oxygen and steam) and electrochemical reactions for water splitting. Additionally, the short-term stability of single cell in H 2 and CH 4 are also studied. • A LSM oxygen-electrode-supported RSOC is fabricated by tape casting, co-sintering and impregnation techniques. • Significant power density of 436.0 and 377 mW/cm−2 is obtained at 750 °C using H 2 and CH 4 as fuel respectively. • Good electrolysis performance of −0.718 A cm−2 at 1.3 V with 50% H 2 O is achieved at 750 °C. • Short-term stability of single cell in H 2 and CH 4 fuel is evaluated at 600 °C. [ABSTRACT FROM AUTHOR]

Two novel wide bandgap copolymers based on quinoxalino[6,5-f]quinoxaline (NQx) acceptor block, PBDT-NQx and PBDTS-NQx, are successfully synthesized for efficient nonfullerene polymer solar cells (PSCs). The attached conjugated side chains on both benzodithiophene (BDT) and NQx endow the resulting copolymers with low-lying highest occupied molecular orbital (HOMO) levels. The sulfur atom insertion further reduces the HOMO level of PBDTS-NQx to −5.31 eV, contributing to a high open-circuit voltage, Voc, of 0.91 V. Conjugated n-octylthienyl side chains attached on the NQx skeletons also significantly improve the π-π* transitions and optical absorptions of the copolymers in the region of short wavelengths, which induce a good complementary absorption when blending with the low bandgap small molecular acceptor of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene. The wide absorption range makes the active blends absorb more photons, giving rise to a high short-circuit current density, Jsc, value of 15.62 mA cm−2. The sulfur atom insertion also enhances the crystallinity of PBDTS-NQx and presents its blend film with a favorable nanophase separation, resulting in improved Jsc and fill factor (FF) values with a high power conversion efficiency of 11.47%. This work not only provides a new fused ring acceptor block (NQx) for constructing high-performance wide bandgap copolymers but also provides the NQx-based copolymers for achieving highly efficient nonfullerene PSCs. [ABSTRACT FROM AUTHOR]

The surface temperature of the thin-walled parts deposited by gas metal arc welding (GMAW)- and double-electrode gas meal arc welding (DE-GMAW)-based additive manufacturing (AM) techniques was captured through the infrared thermography technique. The dimensions of the molten pool in the deposition process including length, depth, and width were reduced in different degrees by the bypass arc during the DE-GMAW-based AM. The volume of the molten pool can decrease by about 30% in DE-GMAW under the same deposition rate. The volume of the high-temperature metal for the deposited parts during DE-GMAW-based AM was smaller than that during GMAW-based AM when depositing the high layer. The mean temperature of the deposited parts after the cooling process in DE-GMAW-based AM was lower under the same condition. The bypass arc in DE-GMAW-based AM is conducive to the reduction of the heat accumulation in the deposited thin-walled parts without a corresponding decrease in the deposition rate. [ABSTRACT FROM AUTHOR]

An infrared camera after calibration test was used to capture the surface temperature of the deposited thin-wall parts for investigating the thermal behavior of gas metal arc welding (GMAW) based additive manufacturing (AM). The temperature field cloud pictures indicated that as the deposition height increased, the heat accumulation of the deposited parts became serious. Through extending the inter-layer cooling time, the high temperature area and the mean temperature of the thin-wall part decreased while the temperature gradient and cooling rate of the deposited part increased. But excessive inter-layer cooling time cannot reduce heat accumulation of the deposited parts effectively and will make the deposition process time-consuming. The comparison of the final parts in forming appearance with different inter-layer cooling time indicated that the moderate prolongation of inter-layer cooling time contributed to improvement of the surface quality and reduction of the total height difference. Using the alternate inter-layer cooling time can improve the forming quality of the thin-wall part distinctly with a little increase of the deposition time in GMAW based AM. [ABSTRACT FROM AUTHOR]

3D point cloud registration is a fundamental and critical issue in 3D reconstruction and object recognition. Most of the existing methods are based on local shape descriptor. In this paper, we propose a discriminative and robust local shape descriptor-Regional Curvature Map (RCM). The keypoint and its neighboring points are firstly projected onto a 2D plane according to a robust mapping against normal errors. Then, the projection points are quantized into corresponding bins of the 2D support region and their weighted curvatures are encoded into a curvature distribution image. Based on the RCM, an efficient and accurate 3D point cloud registration method is presented. We firstly find 3D point correspondences by a RCM searching and matching strategy based on the sub-regions of the RCM. Then, a coarse registration can be achieved with geometrically consistent point correspondences, followed by a fine registration based on a modified iterative closest point (ICP) algorithm. The experimental results demonstrate that the RCM is distinctive and robust against normal errors and varying point cloud density. The corresponding registration method can achieve a higher registration precision and efficiency compared with two existing registration methods. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of the welded joints of 6252 armor steel and Q550D high-strength low-alloy (HSLA) steel welded by MIG welding were studied. ER70S-G and ER140S-G were used as fillers to obtain welded joints with good formation and no faults. The joint microstructure (OM) analysis showed that a large Widmanstätten structure was observed at the fusion line on the Q550D side, and the apparent grain sizes changed on the 6252 side. Cylindrical ferrite growth along the bainite grain boundary was observed in the ER70S-G filler weld zone, while the ER140S-G filler weld zone was occupied by lower bainite structures. The XRD phase analysis showed that more Fe-Ni-Cr compounds and less ferrite were formed in the ER140S-G filler weld. The hardness test showed that the hardness of the HAZ on the 6252 side was significantly higher than that of the BM and the WZ, and the welded joint obtained by the ER140S-G filler had a higher hardness. The tensile strength test showed that WZ (>772 MPa) had a higher strength than Q550D BM, and the tensile fracture (SEM) was primarily a ductile fracture. The impact test results showed that the welded joint had better impact resistance at room temperature, but the impact absorption energy of the weld and the heat-affected zone was strongly affected by changes in temperature, and brittle fracture occurred easily at low temperatures. [ABSTRACT FROM AUTHOR]

Bioelectricity is defined as endogenous electrical signaling mediated by the dynamic distribution of charged molecules. Recently, increasing evidence has revealed that cellular bioelectric signaling is critical for regulating embryonic development, regeneration, and congenital diseases. However, systematic real-time in vivo dynamic electrical activity monitoring of whole organisms has been limited, mainly due to the lack of a suitable model system and voltage measurement tools for in vivo biology. Here, we addressed this gap by utilizing a genetically stable zebrafish line, Tg (ubiquitin: ASAP1), and ASAP1 (Accelerated sensor of action potentials 1), a genetically encoded voltage indicator (GEVI). With light-sheet microscopy, we systematically investigated cell membrane potential (Vm) signals during different embryonic stages. We found cells of zebrafish embryos showed local membrane hyperpolarization at the cleavage furrows during the cleavage period of embryogenesis. This signal appeared before cytokinesis and fluctuated as it progressed. In contrast, whole-cell transient hyperpolarization was observed during the blastula and gastrula stages. These signals were generally limited to the superficial blastomere, but they could be detected within the deeper cells during the gastrulation period. Moreover, the zebrafish embryos exhibit tissue-level cell Vm signals during the segmentation period. Middle-aged somites had strong and dynamic Vm fluctuations starting at about the 12-somite stage. These embryonic stage-specific characteristic cellular bioelectric signals suggest that they might play a diverse role in zebrafish embryogenesis that could underlie human congenital diseases. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is one of the most frequent gastrointestinal cancers. MicroRNAs (miRNAs) have been proved to be unusually expressed in CRC progression and thus alter multiple pathological processes in CRC cells. However, the specific roles and mechanisms of miR-22 in CRC have not been clearly reported. MicroRNA-22 (miR-22) and MYC-associated factor X (MAX) expressions were determined by RT-qPCR in CRC tissues and cells. The targeted regulatory effects of miR-22 and MAX were confirmed by luciferase reporter and coimmunoprecipitation assays. Also, gain- and loss-of-function and rescue experiments were used to elucidate the function and mechanism of miR-22 and MAX in CRC cells and the mouse xenograft model. We discovered that miR-22 was hypermethylated and downregulated, while MAX was upregulated in CRC. miR-22 markedly inhibited migration, invasion, glycolysis, and cancer stem cell transcription factors in CRC cells. In addition, it was found that miR-22 can directly target MAX. Additional functional experiments confirmed that MAX overexpression can rescue the effects of miR-22 on the behavior of CRC cells. This study suggested that miR-22, as a cancer suppressor, participates in CRC progression by targeting MAX, which might provide basic information for therapeutic targets for CRC. [ABSTRACT FROM AUTHOR]

High porosity has been one of the main issues that limit the application of high-strength aluminum alloys produced by wire and arc additive manufacturing. This study attempts to reduce pores in 2219 aluminum alloys fabricated using double-electrode gas metal arc additive manufacturing (DE-GMA-AM). The effects of bypass current ratio on layer dimension, remelting area, and the number of pores were studied based on single-layer tests. Moreover, the influences of bypass current ratio on mean diameter, mean area, area percentage, radius ratio, and the number of porosities were investigated via depositing thin-walled parts. As the bypass current ratio increases, the layer height increases, and the layer width, the remelted area, and the number of the pores decrease. Pores are mainly distributed in the vicinity of the strips, and the quantity and area percentage in the middle region decrease first and then increase as the bypass current ratio increases. By increasing the bypass current ratio from 0 to 70%, the number of the pores and the area percentage in the middle region decrease by 68.6% and 72.6%, respectively. Porosity in the aluminum alloy parts fabricated using DE-GMA-AM can be significantly alleviated within a certain bypass current range. [ABSTRACT FROM AUTHOR]

Star tracker is an important instrument of measuring a spacecraft’s attitude; it measures a spacecraft’s attitude by matching the stars captured by a camera and those stored in a star database, the directions of which are known. Attitude accuracy of star tracker is mainly determined by star centroiding accuracy, which is guaranteed by complete star segmentation. Current algorithms of star segmentation cannot suppress different interferences in star images and cannot segment stars completely because of these interferences. To solve this problem, a new star target segmentation algorithm is proposed on the basis of mathematical morphology. The proposed algorithm utilizes the margin structuring element to detect small targets and the opening operation to suppress noises, and a modified top-hat transform is defined to extract stars. A combination of three different structuring elements is utilized to define a new star segmentation algorithm, and the influence of three different structural elements on the star segmentation results is analyzed. Experimental results show that the proposed algorithm can suppress different interferences and segment stars completely, thus providing high star centroiding accuracy. [ABSTRACT FROM AUTHOR]

A novel additive manufacturing (AM) system using double electrode gas metal arc welding (DE-GMAW) was developed to fabricate metallic products. The width of the deposited multi-layer parts decreased with the increasing of the bypass current and the deposited height increased in proportion to the bypass current under the same deposition rate. The height difference between arc striking point and arc extinguishing point in the deposited parts was reduced by the bypass arc. The coefficient of materials utilization increased more than 10% using DE-GMAW for depositing thin-wall parts within a certain range of bypass current. The DE-GMAW based AM shows promise to fabricate narrower thin-wall components with high deposition rate and has higher deposition efficiency, compared with the normal GMAW based AM. [ABSTRACT FROM AUTHOR]

Double-sided arc horizontal welding is a new process for high-strength steel thick plate. This study aims at studying thermal cycle and microstructure of backing weld. The special heating cycle with two peaks in double-sided double-arc welding is beneficial to the generation of microstructure with good strength and toughness, due to the effect of preheating and postheating. The microstructure was a mixture of ferrite and lath martensite. The heat-affected zone (HAZ) in the root area was overheated, owing to the shape of groove in the horizontal welding, resulting in meshes in the grain boundary. The meshes were analyzed to be the tempered martensite. Hardness tests showed that there were some softened regions in the HAZ on account of high-temperature tempering. [ABSTRACT FROM AUTHOR]

This study presents a robust motion deblurring method in which an adaptive prediction is used to extract the informative regions for kernel estimation. The prediction not only sharpens the blurry edges, but also adaptively predicts the large scale structure for kernel estimation. It allows to only use the alternating minimisation with a computationally efficient Gaussian prior for both the image and kernel while without employing thoughtful attention such as multi‐scale scheme or kernel refinement. Extensive experiments were carried out to validate the proposed method and to compare it with some previous approaches. The experiment results demonstrated that the approach achieves, if not better than, state‐of‐the‐art results for uniformly blurred images. [ABSTRACT FROM AUTHOR]

Iron and steel processing is a complicated system in which various processing units and environmental boundaries exist. Mass and energy metabolize on those environmental boundaries. The morphology of an environmental boundary can shape how mass and energy interact in an iron and steel industrial system. Environmental boundaries in these situations couple all subsystems together to constitute an integrating system in the form of a hierarchical model. The metabolic behaviours are simulated and optimized by using the genetic algorithm of NSGA-II based on the energy intensity indicator under the conservation law of mass and energy. The hierarchical morphology and coupling styles of environmental boundaries in an iron and steel industrial system are fully demonstrated through the characterization of the metabolic behaviours of mass and energy. This study is based on a comparison of the computed values of metabolic behaviours with actual data from an iron and steel company located in the East of China. This investigation shows that the morphological and coupling model of environmental boundary is valid for a complex iron and steel industrial system. This will lead to better resource allocation and more environmental benefits. [ABSTRACT FROM AUTHOR]

An autonomous star identification algorithm is described in this study. This algorithm iteratively determines a catalog star, the distances of which to its neighbors are similar to those of a given sensor star and its neighboring stars, until a unique match is found. In each iteration, only the catalog stars that receive sufficient votes are used in the subsequent steps. We also develop a useful probabilistic model for performance prediction and evaluation. Analysis indicates that spurious star pairings are decreased exponentially after each iteration. The simulation and real sky image results show that the proposed approach is more robust than conventional algorithms and requires fewer resources. [ABSTRACT FROM AUTHOR]

This work presents a no-reference sharpness metric for Gaussian blurred image. The metric is based on the notion of relative blur. The key concept is that the judgement on the sharpness closely relates to the degree of convenience for recognizing image objects on a certain scale. Based on this concept, the proposed metric is defined as relative blur with respect to certain object scale using an absolute blur measure. The object scale is characterized by a granularity analysis of image content. And the absolute blur is built on an analysis of edge local gray level distribution. The performance of the metric is tested and compared with some outstanding existing metrics in this field on three widely used databases. The experiment results show that the proposed metric can predict the sharpness of images in varying databases with high accuracy and reliability. [ABSTRACT FROM AUTHOR]

• Crucial heat treatment is employed to SS308L manufactured by DW-GTA-AM. • δ ferrite is fewer in heat-treated SS308L than in as-deposited SS308L. • Corrosion resistance of SS308L increases along with the heat-treated temperature. Heat treatment is a critical approach to improve the microstructure and properties of SS308L fabricated in double wire gas tungsten arc additive manufacturing (DW-GTA-AM). The influence of heat treatment on the microstructure and corrosion properties of SS308L was studied. The microstructures of the samples heat treated at 1000, 1050 and, 1100 ℃ for one hour consist of δ ferrite and austenite, and δ ferrite spheroidizes gradually. Compared with the as-deposited sample, the amount of δ ferrite is negatively correlated with the heat-treated temperature. Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) measurements indicate that the corrosion resistance increases along with the heat-treated temperature, which can be attributed to that a higher heat-treated temperature results in a thicker and more compact passive film, dissolution of more δ ferrite, and better element diffusion. The corrosion resistance of SS308L is mainly affected by the secondary phase and element distribution. [ABSTRACT FROM AUTHOR]

This paper introduces a high-speed all-hardware scale-invariant feature transform (SIFT) architecture with parallel and pipeline technology for real-time extraction of image features. The task-level parallel and pipeline structure are exploited between the hardware blocks, and the data-level parallel and pipeline architecture are exploited inside each block. Two identical random access memories are adopted with ping-pong operation to execute the key point detection module and the descriptor generation module in task-level parallelism. With speeding up the key point detection module of SIFT, the descriptor generation module has become the bottleneck of the system's performance; therefore, this paper proposes an optimized descriptor generation algorithm. A novel window-dividing method is proposed with square subregions arranged in 16 directions, and the descriptors are generated by reordering the histogram instead of window rotation. Therefore, the main orientation detection block and descriptor generation block run in parallel instead of interactively. With the optimized algorithm cooperating with pipeline structure inside each block, we not only improve the parallelism of the algorithm, but also avoid floating data calculation to save hardware consumption. Thus, the descriptor generation module leads the speed almost 15 times faster than a recent solution. The proposed system was implemented on field programmable gate array and the overall time to extract SIFT features for an image having \(512\times 512\) pixels is only 6.55 ms (sufficient for real-time applications), and the number of feature points can reach up to 2900. [ABSTRACT FROM PUBLISHER]

Highlights: [•] It only needs a LRF and a planar object. [•] It is well suited for on-site calibration in large spatial environments. [•] The relative distance error is 0.3‰ when the distance between cameras is 4m. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new spectral multivariate calibration method is proposed for non-linearity. [•] In quantitative analysis, the proposed method shows the best prediction performance. [•] The proposed method explicitly exhibits the type and amount of the non-linearity. [•] The proposed method has distinct adaptability for the complex spectra model. [•] The good performance by the proposed method for biochemical analysis can be expanded. [Copyright &y& Elsevier]