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Video foreground detection (VFD), as one of the basic pre-processing tasks, is very essential for subsequent target tracking and recognition. However, due to the interference of shadow, dynamic background, and camera jitter, constructing a suitable detection network is still challenging. Recently, convolution neural networks have proved its reliability in many fields with their powerful feature extraction ability. Therefore, an interactive spatio-temporal feature learning network (ISFLN) for VFD is proposed in this paper. First, we obtain the deep and shallow spatio-temporal information of two paths with multi-level and multi-scale. The deep feature is conducive to enhancing feature identification capabilities, while the shallow feature is dedicated to fine boundary segmentation. Specifically, an interactive multi-scale feature extraction module (IMFEM) is designed to facilitate the information transmission between different types of features. Then, a multi-level feature enhancement module (MFEM), which provides precise object knowledge for decoder, is proposed to guide the coding information of each layer by the fusion spatio-temporal difference characteristic. Experimental results on LASIESTA, CDnet2014, INO, and AICD datasets demonstrate that the proposed ISFLN is more effective than the existing advanced methods.

Nature Communications, 13 (1), ISSN:2041-1723

In order to solve the problem of environmental pollution caused by construction waste, one typical waste of red bricks was selected as raw materials in recycled concrete. This study presented recycled concrete by substitution some natural aggregates with treated red brick aggregates to study and analyze the mechanism degradation law of recycled brick aggregates concrete in the cold region. Total fifteen categories specimens and three experimental parameters were considered, which included numbers of freeze-thaw cycles (0, 50, and 100), steel fiber admixtures (0%, 1%, and 2%), and brick aggregate substitution rates (0%, 25%, 50%, 75%, and 100%), respectively. The quick freeze-thaw test method was selected to investigate the degradation law of mass loss rate and relative dynamic elastic modulus of recycled concrete under various freeze-thaw cycles. The digital microscope and SEM were used to observe the internal microstructural changes of the specimens under different freeze-thaw times. In addition, the microscopic damage morphology and damage mechanism of the specimens were analyzed. Finally, the flexural strength of the frost-damaged specimens was tested to analyze the mechanical deterioration of the recycled concrete, and the numerical model corresponding to steel fiber dosing and recycled aggregate replacement rate was presented. The gray correlation analysis was used to quantify the influence of each experimental variable on the corresponding experimental indexes under various freeze-thaw cycles. Results showed that the specimen's mass decreased after freeze-thaw cycles, and the mass loss exerted the most serious for the specimens at 50% and 75% brick substitution rates. In addition, the specimens showed the best relative dynamic modulus and the maximum flexural strength when the steel fiber doping was 1%. The numerical model agreed with experimental data and effectively predicted the specimens' mass loss rate, relative dynamic modulus, and flexural strength after freeze-thaw cycles. The gray correlation analysis showed that the steel fiber contents had a maximum correlation with the flexural strength, the brick substitution rates for the relative dynamic modulus, and mass loss controls the freeze-thaw cycles.

Moving object detection (MOD) is a crucial research topic in the field of computer vision, but it faces some challenges such as shadows, illumination, and dynamic background in practical application. In the past few years, the rise of deep learning (DL) has provided fresh ideas to conquer these issues. Inspired by the existing successful deep learning framework, we design a novel pyramid attention-based architecture for MOD. On the one hand, we propose a pyramid attention module to get pivotal target information, and link different layers of knowledge through skip connections. On the other hand, the dilated convolution block (DCB) is dedicated to obtain multi-scale features, which provides sufficient semantic information and geometric details for the network. In this way, contextual resources are closely linked and get more valuable clues. It helps to obtain a precise foreground in the end. Compared with the existing conventional techniques and DL approaches on the benchmark dataset (CDnet2014), the experiments indicate that the performance of our algorithm is better than previous methods.

Both the first and the second derivatives of the chemical potential with respect to the temperature, for any system of noninteracting bosons, are shown to be negative. For noninteracting fermions, these derivatives can be either negative or positive, but for generic spectra they are both negative at higher temperatures.

BackgroundRisk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA.MethodsA retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic grade of PFOA and tibiofemoral osteoarthritis (TFOA), lateral and medial trochlear inclination angle, sulcus angle, and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG) and patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters, and the relationships between each of these measures and the severity of PFOA were investigated.ResultsBy studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P< 0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle; and type I patella was 8.80 (p= 0.043), 16.51 (P< 0.001), 0.04 (P< 0.001), and 0.18 (p= 0.048) respectively.ConclusionsExtreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.

In a seminal work, Gozar et al. reported on the high-temperature interface superconductivity in bilayers of insulating La2CuO4 and metallic La2−xSrxCuO4 (x=0.45). An interesting question to address is how general and robust this interface superconductivity is. In the past, the cuprate bilayers were grown in a unique atomic-layer molecular beam epitaxy system, with a Sr doping range of x≤0.47, and the atomically flat interface was thought to be indispensable. Here, we have fabricated bilayers of La2CuO4 and La2−xSrxCuO4 by pulsed laser deposition. We have tried to extend the nominal doping range of Sr from the previous maximum of 0.47 to the present 1.70 (the nominal Sr content in the targets). X-ray diffraction result indicates that our La2−xSrxCuO4 films with x≤0.60 have very high crystalline quality; but the film crystalline structure degrades gradually with further increasing x, and finally the structure is fully lost when x reaches 1.40 and higher. Although the film quality scatters dramatically, our experiments show that there exists superconductivity for bilayers in nearly the entire over-doped Sr range, except for a non-superconducting region at x∼0.80. These observations demonstrate that the interface superconductivity in copper oxides is very general and robust.

Modern collisional orogens represent the natural laboratory for the study of metallogeny in continental collision zones. The Pyrenees, Alps, Zagros and Himalaya are all associated with Neo-Tethyan subduction and represent the youngest collisional orogens on Earth. Here, we compare these four orogens in terms of their composition, architecture, tectonic evolution, and metallogenic systems. The four orogens can be divided into simple and composite types. Simple orogens are represented by the Pyrenees and the Alps, and are characterized by narrow linear shapes in plain view and symmetric structures in cross-section, are free of arc magmatism, and are associated with the Mississippi Valley Valley-type Pb-Zn and orogenic gold deposits. The mineral deposits that form in these simple collisional orogens are generally related to processes that occur in the middle and upper crust. In contrast, composite orogens, as exemplified by the Zagros-Iranian and Himalayan-Tibetan Plateaus, are associated with broad orogenic plateaus in plain view and asymmetrical structures in cross-section, record extensive arc magmatism in continental margins, and are associated with a variety of deposit types including carbonatite-related rare earth element (REE), porphyry Cu-Mo, orogenic Au, Mississippi Valley type Pb-Zn, and detachment-fault-related polymetallic deposits. Although the subduction of Neo-Tethys oceanic crust occurred before the creation of simple collisional orogens in the Pyrenees and the Alps, these areas do not show the record of continental arc magmatism. In contrast, the composite collisional orogens are associated with the development of huge continental margin arcs prior to continental subduction, and the subduction was followed by reactivation of the subduction-modified arc lithospheric material, generating the ore-forming systems in these regions.

Grouping different transition metal oxides together by interface engineering is an important route toward emergent phenomenon. While most of the previous works focused on the interface effects in perovskite/perovskite heterostructures, here we reported on a symmetry mismatch-driven spin reorientation toward perpendicular magnetic anisotropy in perovskite/brownmillerite heterostructures, which is scarcely seen in tensile perovskite/perovskite heterostructures. We show that alternately stacking perovskite La2/3Sr1/3MnO3 and brownmillerite LaCoO2.5 causes a strong interface reconstruction due to symmetry discontinuity at interface: neighboring MnO6 octahedra and CoO4 tetrahedra at the perovskite/brownmillerite interface cooperatively relax in a manner that is unavailable for perovskite/perovskite interface, leading to distinct orbital reconstructions and thus the perpendicular magnetic anisotropy. Moreover, the perpendicular magnetic anisotropy is robust, with an anisotropy constant two orders of magnitude greater than the in-plane anisotropy of the perovskite/perovskite interface. The present work demonstrates the great potential of symmetry engineering in designing artificial materials on demand., Complex oxide heterostructures exhibit multifunctional behaviour that could be used in a range of device applications. Here, the authors observe that reconstruction at oxide perovskite/brownmillerite interfaces leads to perpendicular magnetic spin orientation, with potential use in spintronic devices.

Gold (Au) nanoparticles were introduced into thin films of layered cobaltites to decrease the sheet resistance and improve the transparent conducting performance of the films. c-axis-oriented Bi2Sr2Co2O8 thin films dispersed with Au particles with diameters of about 5–10 nm were obtained by pulsed laser ablation of a Bi2Sr2Co2O8 ceramic target on which a piece of fan-shaped Au foil was attached. The resulting Bi2Sr2Co2O8/Au composite thin films, with the Au concentration of about 1.6 at.%, showed a very low resistivity of about 3.0 mΩ cm at room temperature and a reasonable optical transmittance of about 48 % in the visible range, resulting in a high figure of merit of about 2270 MΩ−1. This value is comparable to those reported for the state-of-the-art p-type transparent conducting oxides and is about 1.7-fold higher than that of the pure Bi2Sr2Co2O8 thin films.

Reported here is a water-soluble ligand, N-(sulfoethyl)-iminodiacetic acid (H3SEIDA), used for the complexation of uranyl ions. A coordination compound composed of uranyl cation and N-(sulfonatoethyl)-ammoniodiacetate (SEADA2−) zwitterion was synthesized from an acidic aqueous solution. This compound features a 2D undulating fes (4.82) coordination layer that is stacked and linked by hydrogen-bonding interaction to form a 3D supramolecular framework with a 1D larger-cycle channel. Thermal analysis demonstrates the relatively weak bonding between uranyl cation and SEADA2− zwitterion. The monomeric uranyl-based fluorescence emission is red-shifted by about 5 nm compared to that of uranyl nitrate hexahydrate. The hydrothermal synthesis of this uranyl compound was successfully applied to the sequestration of uranyl ions.

Platinum metal, being nonmagnetic and with a strong spin-orbit coupling interaction, has been deposited on weak ferromagnetic Bi0.9La0.1FeO3 thin films. The Hall effect is studied as a function of the polarization direction of multiferroic Bi0.9La0.1FeO3 thin films, as well as magnetic field (H) and temperature (T). For the two polarization directions, besides the obvious difference of the anomalous Hall resistance RAH, it increases sharply with decreasing temperature and even changes sign, thus violating the conventional expression. This observations indicate local magnetic moments in Pt caused by the local electric fields at the interface of Bi0.9La0.1FeO3 films. Also, possible proximity effects and induced magnetic ordering in Pt on weak ferromagnetic Bi0.9La0.1FeO3 thin films of both upward and downward polarization states may exist and their contribution to the spin-related measurements should not be neglected.

Abnormal percolative transport in inhomogeneous systems has drawn increasing interests due to its deviation from the conventional percolation picture. However, its nature is still ambiguous partly due to the difficulty in obtaining controllable abnormal percolative transport behaviors. Here, we report the first observation of electric-field-controlled abnormal percolative transport in (011)-Pr(0.7)(Ca(0.6)Sr(0.4))(0.3)MnO3/0.7Pb(Mg(1/3)Nb(2/3))O3-0.3PbTiO3 heterostructure. By introducing an electric-field-induced in-plane anisotropic strain-field in a phase separated PCSMO film, we stimulate a significant inverse thermal hysteresis (~ -17.5 K) and positive colossal electroresistance (~11460%), which is found to be crucially orientation-dependent and completely inconsistent with the well accepted conventional percolation picture. Further investigations reveal that such abnormal inverse hysteresis is strongly related to the preferential formation of ferromagnetic metallic domains caused by in-plane anisotropic strain-field. Meanwhile, it is found that the positive colossal electroresistance should be ascribed to the coactions between the anisotropic strain and the polarization effect from the poling of the substrate which leads to orientation and bias-polarity dependencies for the colossal electroresistance. This work unambiguously evidences the indispensable role of the anisotropic strain-field in driving the abnormal percolative transport and provides a new perspective for well understanding the percolation mechanism in inhomogeneous systems.

Experiments were carried.out in Chongging-a city seriously damaged by acid precipitation in southwest China — to explore chemical compositions of open bulk precipitation, throughfall and stemflow in a Masson pine (Pinus massoniana) forest. The results showed that annual mean pH values of and annual ion depositions in the three types of rain water were 4.47 and 50.6 g m−2, 3.82 and 69.7 g m−2, and 2.92 and 0.215 g m−2 respectively. pH values demonstrated an obvious seasonal variation; they were lower in winter than in the rest of the year. Ca2+ and NH inf4 sup+ together made up more than 80% of the total cation, while SO in4 sup2− alone contributed over 90% to the total anion. This high level of SO in4 sup2− in rain water in Chongqing, which outran those found in other cities in China, was closely related to the combustion of locally produced coal that contains 3 to 5% sulphur. Thus, acid precipitation in Chongqing is of a typical sulphuric-acid type.