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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.

To improve the mechanical properties of carbon/carbon (C/C) composites, in-situ synthetized single-crystalline hafnium carbide nanowires (HfCnws) were introduced into the carbon fiber preforms by electrophoresis-thermal evaporation method. The Multi-walled carbon nanotubes (MWCNTs) were utilized as the carbon source and templates for forming HfCnws. The microstructure, chemical composition and mechanical properties of the HfCnws modified carbon/carbon (HfCnws-C/C) composites were characterized. Results reveal that HfC is produced preferentially in the inner nodular parts and end parts of MWCNTs. The raising heat-treatment temperature would influence the diffusion rate of Hf atoms and then the number of nucleation sites, which further changed the aspect ratio and morphology of HfCnws. The HfCnws have refined the grain size of pyrolytic carbon (PyC), and significantly improve the flexural strength of C/C composites by 79.3%.

This paper is concerned with the exponential stabilization of switched linear systems subject to actuator saturation with both stabilizable subsystems and unstabilizable subsystems for continuous-time case and discrete-time case, respectively. Sufficient conditions for the exponential stabilization under dwell time switching under the cases of continuous-time and discrete-time are established by using a novel class of multiple time-varying Lyapunov function. The existence conditions for stabilizing controllers are presented in terms of linear matrix inequalities (LMIs) for the continuous-time case and the discrete-time case, respectively. Two optimization problems are proposed for obtaining the maximal attraction region. The problem of exponential stabilization for switched system subject to actuator saturation with asynchronous switching controller is also studied. Several numerical examples are presented to prove the validity of the obtained results.

In this article, a sensorless field-oriented vector control strategy combined with an improved adaptive sliding mode observer and a back electromotive force (back EMF) observer is presented for a surface permanent magnet synchronous motor. First, based on a sliding mode, a current adaptive observer with estimation of back EMF is proposed to obtain the error of the back EMF, which can reduce system chattering. Then, a back EMF observer based on the back EMF error is constructed to adaptively track the rotor speed and position, which avoids complicated computation. Moreover, the stability of two observers is proved by using the Lyapunov stability theory. Finally, some simulations and experiments are given to show that the proposed method can track the changes of rotor speed and position with good characters, such as fast convergence, little chattering, and good robustness.

A constitutive model that can describe the damage evolution of anisotropic metal sheets during the complex forming processes which experience wide stress triaxiality history is essential to accurately predict the deformation and rupture behaviors of the processes. In this study, a modified Lemaitre damage criterion which couples with the anisotropic Barlat 89 yield function is established. The effects of stress triaxiality, Lode parameter and shear stress on damage accumulation are considered in the constitutive model. The model is numerically implemented and applied to fracture prediction in tensile tests with different stress triaxialities and a complex deformation process with wide stress triaxiality history. The good consistency of predictions and experiments indicates that the modified Lemaitre damage model has excellent fracture prediction ability. Finally, the accuracy of the model is analyzed and discussed.

Flow forming is a promising technique to manufacture thin-walled tubular parts with cross inner ribs (longitudinal and transverse inner ribs, LTIRs) which are highly demanded in aerospace field. However, the nature of local loading results in complicated material flow and consequently affects the formation of inner ribs by die filling. Therefore, flow forming experiment along with finite element (FE) simulation was carried out to study the material flowing behavior in the flow forming of stiffened parts, thus to reveal the die filling mechanism. The results showed that varied rib height occurred after flow forming on account of the different die filling mechanisms of longitudinal inner ribs (LIRs) and transverse inner ribs (TIRs). Namely, the axial tensile strain results in a low LIR, while it is a nearly plane strain state for TIR and the radial tensile strain in the inner layer of TIR is in charge of the larger TIR height. In order to improve the rib height, large wall thickness reduction and feed ratio should be used. The law of die filling in flow forming of thin-walled tubular parts with LTIRs will provide guidance for the integrated manufacture of stiffened thin-walled tubular parts in a high quality.

To incorporate spintronics functionalities into two-dimensional devices, it is strongly desired to get two-dimensional electron gases (2DEGs) with high spin polarization. Unfortunately, the magnetic characteristics of the typical 2DEG at the LaAlO

A hybrid numerical method for heat conduction of functionally graded plate with the variable gradient parameters under the H(t) heat source was studied. A weighted residual equation of heat conduct...

Moving shadow elimination plays an important role in the field of moving object detection. However, the accuracy of shadow elimination is an open question, due to illumination and complex texture. Furthermore, the problem of misclassification of moving object caused by shadow has also become increasingly serious. To address this problem, this paper presents a moving shadow elimination algorithm based on the fusion of multi-feature pattern, which can enhance the accuracy of moving object detection system. In this approach, a dual-channel HSV color space feature and a uniform extended scale invariant local ternary pattern (UESILTP) texture feature are synthesized to elimination shadow. It greatly overcomes the misjudgment of dark object by color feature and the false detection caused by inconspicuous texture characteristics of moving object. Meantime, a method of region growth is adopted to fill the existing cavities in the color space. Finally, qualitative and quantitative comparisons with state-of-the-art methods show that the algorithm is effective.

The immersion ultrasonic C-scan ((IUCT) test was conducted for evaluating the bonded ratio of the TC4 diffusion bonded joints. The signal characteristics reflected by the typical bonding states of the joint, gap, kissing bond, microvoids and sound bond were investigated in the time and frequency domain. Moreover, as for the bonding state of microvoids, its local bonded ratio exhibited a linear relationship with the relative amplitude of its echo signal in the time domain. Based on the echo signal characteristics and the linear relationship about microvoids, a MATLAB algorithm program was developed to calculate the global bonded ratio of bonding interface directly from echo signal of IUCT. The results demonstrated that joint bonded ratio and mechanical properties, especially the tensile strength, could be quantitively evaluated by the combination of IUCT test and the developed MATLAB program.

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.

As living standards increase, the energy consumption in refrigeration, such as air-conditioning and refrigerators, tremendously increases and intensifies global warming. As an alternative for the conventional vapor compression technique, solid state refrigeration based on magnetocaloric effect shows significant potential due to energy-saving and environmental-friendly properties. However, hysteresis loss is a longstanding problem seriously harming refrigeration efficiency. Here, we report novel enhancement of refrigeration efficiency controlled by strain memory effect in FeRh films grown on (011)-PMN-PT substrates. Utilizing nonvolatile strain triggered by a pulse electric field to engineer magnetization process of FeRh film, a nonvolatile large reduction of hysteresis loss, ∼56%, is achieved, consequently effective refrigeration capacity increases to ∼86%. The hysteresis loss can be expected to be eliminated and even turned out to be inverse through enhancing the strain memory effect. As a result, effective refrigeration capacity (RCeffe) can increase to a new height through introducing external mechanical work in a magnetic refrigeration cycle, and the ideal COP (coefficient-of-performance) would break through Carnot limit if only hysteresis loss and the contribution of mechanical work were considered.

Compensated ferrimagnetic thulium iron garnet ceramics were prepared by the sol-gel method, which is significantly better than conventional solid-state reactions. Saturation magnetization yielded a maximum of 16.7 emu/g for specimens sintered at 900 °C. Subsequently, using the TmIG bulk as the target, an epitaxial film was grown by pulsed laser deposition. Furthermore, the spin transport properties of film with an attached 5 nm-thick platinum layer were studied in terms of longitudinal spin Seebeck effect (LSSE) and spin Hall magnetoresistance (SMR). The LSSE coefficient was as high as 0.38 μV/K and the SMR was 0.0072%. These results indicated that the bulk material and thin film presented excellent qualities, which are extremely important for the fundamental investigation of novel spin transport behaviour in compensated ferrimagnetic insulators. These results also provide more alternatives for spintronic materials.

With the help of the two-dimensional electron gas (2DEG) at the LaAlO3–SrTiO3 interface, spin and charge currents can be interconverted. However, the conversion efficiency has been strongly depressed by LaAlO3, which blocks spin transmission. It is therefore highly desired to explore 2DEGs sandwiched between ferromagnetic insulators that are transparent for magnons. By constructing epitaxial heterostructure with ferromagnetic EuO, which is conducting for spin current but insulating for electric current, and KTaO3, we successfully obtained the 2DEGs, which can receive thermally injected spin current directly from EuO and convert the spin current to charge current via inverse Edelstein effect of the interface. Strong dependence of the spin Seebeck coefficient on the layer thickness of EuO is further observed and the propagation length for non-equilibrium magnons in EuO has been determined. The present work demonstrates the great potential of the 2DEGs formed by ferromagnetic oxides for spin caloritronics.

Simulation techniques have been increasingly applied to building performance evaluation and building environmental design. However, uncertain and random factors, such as occupant behaviour, can generate a performance gap between the results from computer simulations and real buildings. This study involved a longitudinal questionnaire survey conducted for one year, along with a continuous recording of environmental parameters and behaviour state changes, in ten offices located in the severe cold region of north-east China. The offices varied from private rooms to open-plan spaces. The thermal comfort experiences of the office workers and their environmental control behaviours were tracked and analysed during summer and winter seasons. The interaction of the thermal comfort experiences of the occupants and behaviour changes were analysed, and window-opening behaviour patterns were defined by applying data mining techniques. The results also generated window-opening behaviour working profiles to link to building performance simulation software. The aim was to apply these profiles to further study the discrepancies between simulation and monitored results that arise from real-world occupant behaviour patterns.

Controlling electronic processes in low-dimension electron systems is centrally important for both fundamental and applied researches. While most of the previous works focused on SrTiO3-based two-dimensional electron gases (2DEGs), here we report on a comprehensive investigation in this regard for amorphous-LaAlO3/KTaO3 2DEGs with the Fermi energy ranging from ∼13 meV to ∼488 meV. The most important observation is the dramatic variation of the Rashba spin–orbit coupling (SOC) as Fermi energy sweeps through 313 meV: The SOC effective field first jumps and then drops, leading to a cusp of ∼2.6 T. Above 313 meV, an additional species of mobile electrons emerges, with a 50-fold enhanced Hall mobility. A relationship between spin relaxation distance and the degree of band filling has been established in a wide range. It indicates that the maximal spin precession length is ∼70.1 nm and the maximal Rashba spin splitting energy is ∼30 meV. Both values are much larger than the previously reported ones. As evidence...

To improve the corrosion resistance of the carbon fiber reinforced magnesium matrix composites (Cf/Mg composites), ZrO2 and ZrB2-SiC/ZrO2 composite coatings were prepared by supersonic atmospheric plasma spraying (SAPS) on Cf/Mg composites. The microstructure and phase composition of the coatings before and after the corrosion test were investigated. Open circuit potential and potentiodynamic polarization tests were measured at room temperature. Results revealed that the corrosion current density ( i corr ) of the ZrO2 coated Cf/Mg composites decreased by one order while the ZrB2-SiC/ZrO2 coated Cf/Mg composites reduced by two orders. Compared with Cf/Mg composites, the corrosion potential ( E corr ) of the ZrO2 and ZrB2-SiC/ZrO2 coated Cf/Mg composites increased by 220.5 mV and 1021.8 mV respectively, indicating that the ZrB2-SiC/ZrO2 composite coatings greatly improve the corrosion resistance of Cf/Mg composites. The uniform distribution of the SiC particles with small grain size in ZrB2 is responsible for the densification of the coating. The ZrB2-SiC/ZrO2 composite coatings provide a barrier for the substrate to impede the entry of Cl- in the corrosion solution, thus exhibiting a better corrosion resistance than the ZrO2 coating.

In-situ ZrC nanowires (ZrCNWs) has been successfully synthesized on carbon cloth by precursor pyrolysis. The morphology, microstructure and chemical composition of the ZrCNWs were characterized by SEM, TEM, EDS and XRD. The results show that the ZrCNWs are single crystal structures with diameters of approximately 500–1000 nm and an aspect ratio of up to 100. A growth model based on SLS (Solid-Liquid-Solid) mechanism is proposed to explain the growth of ZrCNWs, which reveals that the reason for the formation of ZrCNWs was the auxiliary action of the catalyst. The pyrolytic carbon (PyC) has high texture (HT) whose extinction angle is 18–20° and the growth mode of PyC is cone-shaped in ZrCNWs modified C/C composites. The toughening mechanism in ZrCNWs modified carbon/carbon (C/C) composites can be realized by the bridging of ZrCNWs, cracks deflecting, and the enhancement of interfacial bond strength between matrix and fiber. The flexural strength of C/C composites is increased by 163.2% after the introduction of ZrCNWs.

Two-dimensional (2D) van der Waals (vdW) magnets have recently attracted increasing attention, as they provide a novel system for exploring 2D magnetism. However, intrinsic ferromagnetism in 2D systems has almost exclusively been observed at low temperatures, limiting their technological relevance. ${\mathrm{Fe}}_{\mathrm{N}}{\mathrm{Ge}\mathrm{Te}}_{2}$ ($N=3$, 4, and 5) systems are currently becoming the most attractive 2D vdW materials due to their relatively high Curie temperatures and large saturation magnetization. However, the nature of their complex yet intriguing magnetic behaviors is still unclear, in part due to the multiple inequivalent iron sites and iron vacancies. Here, we show evolution of magnetic ordering transitions in ${\mathrm{Fe}}_{5\ensuremath{-}x}{\mathrm{Ge}\mathrm{Te}}_{2}$ with high Curie temperature and a strong saturation magnetization using photoemission electron microscopy and transport measurements. At 275 K, the ferromagnet transitions to a ferrimagnet, and below 110 K transitions to a state with glassy clusters. These are evidenced from temperature-dependent magnetic stripe domain evolution and anisotropic magnetoresistance measurements. Our findings show a clear magnetic ground state of ${\mathrm{Fe}}_{5\ensuremath{-}x}{\mathrm{Ge}\mathrm{Te}}_{2}$ at room temperature which signals that ${\mathrm{Fe}}_{5\ensuremath{-}x}{\mathrm{Ge}\mathrm{Te}}_{2}$ system is a very promising candidate for spintronic devices and provides a material design pathway to further increase the Curie temperature and saturation moments in vdW ferromagnets.

This study investigates the problem of finite-time reduced order synchronization of chaotic systems with uncertainties. Firstly, assume that the unknown parameters and uncertainties are norm-bounded, and then an adaptive scheme is introduced to estimate unknown parameters and uncertainties. Secondly, by employing the finite-time stability, an adaptive controller is constructed to realize the chaos synchronization in order to conquer the problem of nonlinear input of the controller. Finally, an example demonstrates the validity of the proposed controller.

Soft, stimulus-responsive 3D structures created from crosslinked poly(ionic liquid)s (PILs) have been fabricated at unprecedented sub-micron resolution by direct laser writing (DLW). These structures absorb considerable quantities of solvent ( e.g., water, alcohol, and acetone) to produce PIL hydrogels that exhibit stimulus-responsive behavior. Due to their flexibility and soft, responsive nature, these structures are much more akin to biological systems than the conventional, highly crosslinked, rigid structures typically produced using 2-photon polymerization (2-PP). These PIL gels expand/contract due to solvent uptake/release, and, by exploiting inherited properties of the ionic liquid monomer (ILM), thermo-responsive gels that exhibit reversible area change (30 ± 3%, n = 40) when the temperature is raised from 20 °C to 70 °C can be created. The effect is very rapid, with the response indistinguishable from the microcontroller heating rate of 7.4 °C s −1 . The presence of an endoskeleton-like framework within these structures influences movement arising from expansion/contraction and assists the retention of structural integrity during actuation cycling.

Epitaxial strain imposed in complex oxide ultrathin films is recognized as a powerful tool for controlling the ground state of correlated electron system. Here, we achieved simultaneous control of oxygen vacancies, orbital occupancy and magnetic ordering through the facile application of epitaxial strain, both tensile and compressive, in SrCoO3−δ oxygen “sponge” material rather than the ordinary manganites. The oxygen vacancies are enhanced greatly as the strain changes from smaller tensile 1.0% to larger tensile 2.0%, then to moderate compressive −1.0% in SrCoO3−δ films, associated with 3 − δ varying from ∼2.90 to ∼2.835, then to ∼2.72. Highest saturated magnetization is found in the thin films in small tension on La0.3Sr0.7Al0.65Ta0.35O3 substrate and lower values are found in larger tension on SrTiO3 and lowest values in moderate compression on LaAlO3. Meanwhile, electrons prefer to occupy the in-plan oriented orbitals for the tensile strain, in contrast to the preferential out-of-plane orbital occupancy for the compressive state associated with coupled intermediate spin-Co4+ (t2g4eg1)/high spin-Co3+ (t2g4eg2) in different proportions depending on strain states. Such controllable spin and orbital configurations lead to more robust magnetization in tensile strained SrCoO3−δ films than in its compressive counterpart. Our findings provide a nostrum for tailoring and controlling new magnetic, electronic and ionically active properties with strain engineering and further enrich orbital physics in cobaltites.

Respiratory viral infections threaten human life and inflict an enormous healthcare burden worldwide. Frequent monitoring of viral antibodies and viral load can effectively help to control the spread of the virus and make timely interventions. However, current methods for detecting viral load require dedicated personnel and are time-consuming. Additionally, COVID-19 detection is generally relied on an automated PCR analyzer, which is highly instrument-dependent and expensive. As such, emerging technologies in the development of respiratory viral load assays for point-of-care (POC) testing are urgently needed for viral screening. Recent advances in loop-mediated isothermal amplification (LAMP), biosensors, nanotechnology-based paper strips and microfluidics offer new strategies to develop a rapid, low-cost, and user-friendly respiratory viral monitoring platform. In this review, we summarized the traditional methods in respiratory virus detection and present the state-of-art technologies in the monitoring of respiratory virus at POC.

The evolution of the East Asian monsoon (EAM) in the geologic time is of great importance to our understanding of the global climate system. However, variations in the monsoon rainfall and the upper ocean thermal gradient are not well understood in the South China Sea (SCS) during the middle to late Miocene. Here, we present δ18O and Mg/Ca-derived temperature records of the surface and subsurface waters from International Ocean Discovery Program (IODP) Site U1501, and use them to reconstruct the upper ocean thermal structure, which reflects changes in the East Asian summer monsoon (EASM) in the SCS over 13.6–7.3 Ma. The differences between the surface and thermocline records (Δδ18Osurface-thermocline and ΔTsurface-thermocline) indicate a shallower thermocline and increased thermal gradient between the surface and subsurface waters, implying that upper water mixing was weaker during 9.4–7.3 Ma, which may relate to an increased EASM rainfall. Changes in the local seawater δ18Oseawater (δ18OSW) of U1501 also suggest a decrease in the intensity of the EASM rainfall during 13.6–10.2 Ma and an increase during 10.2–7.3 Ma. From the perspectives of moisture supply and general circulation, the initial formation of the western Pacific warm pool (WPWP) and uplift of Tibetan Plateau essentially influenced the variations in the EASM during the middle to late Miocene.

Modulating transport behaviors of two-dimensional electron gases are of critical importance for applications of the next-generation multifunctional oxide electronics. In this study, transport behaviors of LaAlO3/SrTiO3 heterointerfaces modified through the Ni dopant and the light irradiation have been investigated. Through the Ni dopant, the resistances increase significantly and a resistance upturn phenomenon due to the Kondo effect is observed at T < 40 K. Under a 360 nm light irradiation, the interfaces exhibit a persistent photoconductivity and a suppressed Kondo effect at low temperature due to the increased mobility measured through the photo-Hall method. Moreover, the relative changes in resistance of interfaces induced by light are increased from 800 to 6600% at T = 12 K with increasing the substitution of Ni, which is discussed by the band bending and the lattice effect due to the Ni dopant. This work paves the way for better controlling the emerging properties of complex oxide heterointerfaces a...

Two-dimensional electron gas (2DEG) at the perovskite oxide interface exhibits a lot of exotic properties, presenting a promising platform for the exploration of emergent phenomena. While most of the previous works focused on SrTiO3-based 2DEG, here we report on the fabrication of high-quality 2DEGs by growing an amorphous LaAlO3 layer on a (001)-orientated KTaO3 substrate, which is a 5d metal oxide with a polar surface, at a high temperature that is usually adopted for crystalline LaAlO3. Metallic 2DEGs with a Hall mobility as high as ∼2150 cm2/(V s) and a sheet carrier density as low as 2 × 1012 cm–2 are obtained. For the first time, the gating effect on the transport process is studied, and its influence on spin relaxation and inelastic and elastic scattering is determined. Remarkably, the spin relaxation time can be strongly tuned by a back gate. It is reduced by a factor of ∼69 while the gate voltage is swept from −25 to +100 V. The mechanism that dominates the spin relaxation is elucidated.

LiMn0·75Fe0·25PO4/C powders were prepared by a facile hydrothermal and ball-milling method, and then calcined. X-ray diffraction and scanning electron microscopy revealed that the calcination temperature had a strong effect on the structure and morphology of the as-prepared powder, and thus, on the subsequent electrochemical performance of the material. When the calcination temperature was increased from 550 to 700°C, the grain size of LiMn0·75Fe0·25PO4/C increased greatly. The electronic conductivities of the carbon coatings, which were obtained from sucrose and calcined at 550 and 700°C, were investigated. The discharge capacities of LiMn0·75Fe0·25PO4/C decreased with increasing calcination temperature, but electrochemical impedance spectroscopy showed that the charge-transfer resistances of LiMn0·75Fe0·25PO4/C electrodes decreased owing to the increase in the electronic conductivity of the carbon coating. Grain growth played a more important role than the electronic conductivity of the carbon c...

Artificial engineering of an interfacial spin structure of complex oxides with strongly coupled spin, orbital, charge and lattice degrees of freedom is crucially important for the exploration of novel effects associated with magnetic tunneling, exchange biasing, and spin injecting/manipulating, which are the central issues of spintronics. Here we demonstrate the presence of a distinct interlayer coupling between LaMnO3 (LMO) and LaCoO3 (LCO) and the resulting dramatic effect on the spin structure. We found that the LCO layer in (LMO/LCO)5 superlattices exhibits not only an antiferromagnetic coupling with a neighboring LMO layer but also a long-range magnetic order with substantially reduced magnetization. As suggested by density functional theory calculations, interlayer coupling can induce a spatial oscillation of magnetic moment within the LCO layer, resulting in low magnetization.

Being able to tune magnetic anisotropy (MA) by an electric field is crucial for the development of low-power magnetoelectric devices. The authors present an approach for tuning the MA of a manganite film by modulating the crystal phase of a cobaltite cap layer. By driving the cap layer to switch between SrCoO${}_{2.5}$ and SrCoO${}_{3\ensuremath{-}\ensuremath{\delta}}$ structures, reversible tuning of MA between two crystal directions was achieved for the manganite layer, accompanying a change in Mn $3d$ orbital occupancy. This work demonstrates indirect tuning of the magnetic easy axis of this highly spin-polarized manganite, providing guidance for constructing electrically tunable magnetoelectric devices.

Perpendicular magnetic anisotropy (PMA) of magnetic materials has received much attention because of its potential application to spintronics devices. In general, the tensely strained $(001)\text{\ensuremath{-}}\mathrm{L}{\mathrm{a}}_{2/3}\mathrm{S}{\mathrm{r}}_{1/3}\mathrm{Mn}{\mathrm{O}}_{3}$ (LSMO) layer is easy plane. Here we demonstrate that the tensile LSMO layer will exhibit an out-of-plane magnetic anisotropy if it is sandwiched between two $\mathrm{L}{\mathrm{a}}_{1\ensuremath{-}x}\mathrm{S}{\mathrm{r}}_{x}\mathrm{Co}{\mathrm{O}}_{2.5+\ensuremath{\delta}}$ (LSCO) layers. The most remarkable observation is that the PMA enhances with the increase of the Sr content in LSCO. It is $\ensuremath{\sim}2.7\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.16em}{0ex}}\mathrm{erg}/\mathrm{c}{\mathrm{m}}^{3}$ for $x=0.05$ and $\ensuremath{\sim}4.3\ifmmode\times\else\texttimes\fi{}{10}^{6}\phantom{\rule{0.16em}{0ex}}\mathrm{erg}/\mathrm{c}{\mathrm{m}}^{3}$ for $x=0.5$. This value is two orders of magnitude greater than that obtained by compressively straining the LSMO film $(\ensuremath{\sim}{10}^{4}\phantom{\rule{0.16em}{0ex}}\mathrm{erg}/\mathrm{c}{\mathrm{m}}^{3})$. Analysis of high resolution lattice image shows the formation of perovskite/brownmillerite-type interfaces in the multilayers: Brownmillerite-like lattice structure forms in the interfacial layers of LSCO, resulting in a coherent tilting of adjacent $\mathrm{Mn}{\mathrm{O}}_{6}$ octahedra. This in turn leads to, as evidenced by the analysis of x-ray linear dichroism, selective orbital occupation thus spin reorientation. There is evidence that the brownmillerite-structured LSCO is more easily formed when $x$ is high, which explains the growth of anisotropy constant with the increase of Sr content.

Manipulation of oxygen vacancies via electric-field-controlled ionic liquid gating has been reported in many model systems within the emergent fields of oxide electronics and iontronics. It is then significant to investigate the oxygen vacancy formation/annihilation and migration across an additional ferroelectric layer with ionic liquid gating. Here, we report that via a combination of ionic liquid and ferroelectric gating, the remote control of oxygen vacancies and magnetic phase transition can be achieved in SrCoO

The force required to detach a single fibroblast cell in contact with the conducting polymer, polypyrrole doped with dodecylbenzene, was quantified using the Atomic Force Microscope-based technique, Single Cell Force Spectroscopy. The de-adhesion force for a single cell was 0.64 ± 0.03 nN and predominately due to unbinding of α5β1 integrin complexes with surface adsorbed fibronectin, as confirmed by blocking experiments using antibodies. Monophasic pulsed stimulation (50 μs pulse duration) superimposed on either an applied oxidation (+500) or reduction (−500 mV) constant voltage caused a significant decrease in the de-adhesion force by 30%–45% to values ranging from 0.34 to 0.43 nN (±0.02 nN). The electrical stimulation caused a reduction in the molecular-level jump and plateau interactions, while an opposing increase in nonspecific interactions was observed during the cell de-adhesion process. Due to the monophasic pulsed stimulation, there is an apparent change or weakening of the cell membrane properties, which is suggested to play a role in reducing the cell de-adhesion. Based on this study, pulsed stimulation with optimized threshold parameters represents a possible approach to tune cell interactions and adhesion on conducting polymers.The force required to detach a single fibroblast cell in contact with the conducting polymer, polypyrrole doped with dodecylbenzene, was quantified using the Atomic Force Microscope-based technique, Single Cell Force Spectroscopy. The de-adhesion force for a single cell was 0.64 ± 0.03 nN and predominately due to unbinding of α5β1 integrin complexes with surface adsorbed fibronectin, as confirmed by blocking experiments using antibodies. Monophasic pulsed stimulation (50 μs pulse duration) superimposed on either an applied oxidation (+500) or reduction (−500 mV) constant voltage caused a significant decrease in the de-adhesion force by 30%–45% to values ranging from 0.34 to 0.43 nN (±0.02 nN). The electrical stimulation caused a reduction in the molecular-level jump and plateau interactions, while an opposing increase in nonspecific interactions was observed during the cell de-adhesion process. Due to the monophasic pulsed stimulation, there is an apparent change or weakening of the cell membrane properti...

The metallic interface between two oxide insulators, such as LaAlO3/SrTiO3 (LAO/STO), provides new opportunities for electronics and spintronics. However, due to the presence of multiple orbital populations, tailoring the interfacial properties such as the ground state and metal-insulator transitions remains challenging. Here, we report an unforeseen tunability of the phase diagram of LAO/STO by alloying LAO with a ferromagnetic LaMnO3 insulator without forming lattice disorder and at the same time without changing the polarity of the system. By increasing the Mn-doping level, x, of LaAl1-xMnxO3/STO, the interface undergoes a Lifshitz transition at x = 0.225 across a critical carrier density of nc= 2.8E13 cm-2, where a peak TSC =255 mK of superconducting transition temperature is observed. Moreover, the LaAl1-xMnxO3 turns ferromagnetic at x >=0.25. Remarkably, at x = 0.3, where the metallic interface is populated by only dxy electrons and just before it becomes insulating, we achieve reproducibly a same device with both signatures of superconductivity and clear anomalous Hall effect. This provides a unique and effective way to tailor oxide interfaces for designing on-demand electronic and spintronic devices., 18 pages and 6 figures

Spin-orbit torques (SOTs) that arise from materials with large spin-orbit coupling offer a new pathway for energy-efficient and fast magnetic information storage. SOTs in conventional heavy metals and topological insulators are explored extensively, while 5d transition metal oxides, which also host ions with strong spin-orbit coupling, are a relatively new territory in the field of spintronics. An all-oxide, SrTiO3 (STO)//La0.7 Sr0.3 MnO3 (LSMO)/SrIrO3 (SIO) heterostructure with lattice-matched crystal structure is synthesized, exhibiting an epitaxial and atomically sharp interface between the ferromagnetic LSMO and the high spin-orbit-coupled metal SIO. Spin-torque ferromagnetic resonance (ST-FMR) is used to probe the effective magnetization and the SOT efficiency in LSMO/SIO heterostructures grown on STO substrates. Remarkably, epitaxial LSMO/SIO exhibits a large SOT efficiency, ξ|| = 1, while retaining a reasonably low shunting factor and increasing the effective magnetization of LSMO by ≈50%. The findings highlight the significance of epitaxy as a powerful tool to achieve a high SOT efficiency, explore the rich physics at the epitaxial interface, and open up a new pathway for designing next-generation energy-efficient spintronic devices.

Buildings made of snow and ice in severely cold areas can provide people with tourist experiences. Utilizing natural resources in an appropriate manner such as constructing energy efficient residential buildings that are suited to local climate conditions is important for maintaining indoor thermal comfort, creating ecologically living spaces, and reducing energy consumption. In this study, an igloo was built in the traditional manner at Harbin Institute of Technology to detect the heat transfer mechanism of ice and snow, and indoor thermal comfort in an extremely cold region of China. The thermal benefits of the igloo were investigated based on field measurements. Periodic heat transfer theory was applied to study the heat transfer mechanism in the igloo wall and human thermal comfort was analyzed in the chamber and under ambient conditions. The results showed the following. (1) The air temperature and relative humidity were higher and more stable in the chamber without any heating measures. (2) The air temperature was about 4 °C higher in the chamber than the ambient temperature. (3) The maximum snow depth where the ambient temperature affected the chamber temperature was 200 mm. (4) The igloo provided a more comfortable thermal environment compared with the outdoor conditions. These findings may provide the basis for understanding the thermal benefit of igloos based on the utilization of natural resources. Theoretically and practically, our results may provide an experimental basis for studying the heat transfer mechanism to facilitate the establishment of design and construction standards for snow and ice buildings.

Manipulating topotactic phase transformations via orderly ion transfer in complex oxides ABOx is ubiquitous in advanced applications such as ionotronics, ion-batteries and catalysts. Most of such ion-mediated transformations are accomplished by the transfer of oxygen or A-site ions. However, implementing the transformation via the transfer of B-site ions, despite the great challenge to overcome a large cohesive energy, has unique advantage since they host most functional properties of materials. Here, we present a tri-state phase transformation from perovskite (P) to brownmillerite (BM) and to single-layered perovskite (SL) structure via the concerted migration of oxygen and B-site Co-ions in La0.7Sr0.3CoO3 thin films. Ac-STEM, XPS, XAS, PNR, magnetic and electric measurements demonstrated that presented B-site Co-cation transfer is along the CoO4 tetrahedral sub-layer of the BM film, which leads to the reconfiguration of 3d-electrons and spin state in remanent Co ions and causes tremendous changes in magnetic and electric properties: from canted-antiferromagnetic insulator in BM phase to ferromagnetic insulator in SL phase. First-principles calculations revealed that the La3+-doping at A-site largely reduces the cohesive energy of Co-ions in CoO4 and destabilize the CoO4 tetrahedron of BM phase, which explains the formation of Co-ions transfer channel in the CoO4 tetrahedral sub-layer. The present study highlights the effectiveness of regulating topotactic transformation via B-site ions transfer and provides a new pathway for manipulating the topotactic transformation with diverse functionalities.

Structural and magnetic properties of the LaCoO3/SrTiO3 (LCO/STO) multilayers (MLs) with a fixed STO layer of 4 nm but varied LCO layer thicknesses have been systematically studied. The MLs grown on Sr0.7La0.3Al0.65Ta0.35O3 (LSAT) and SrTiO3 (STO) exhibit the in-plane lattice constant of the substrates, but those on LaAlO3 (LAO) show the in-plane lattice constant between those of the first two kinds of MLs. Compared with the LCO single layer (SL), the magnetic order of the MLs is significantly enhanced, as demonstrated by a very slow decrease, which is fast for the SL, of the Curie temperature and the saturation magnetization as the LCO layer thickness decreases. For example, clear ferromagnetic order is observed in the ML with the LCO layer of ∼1.5 nm, whereas it vanishes below ∼6 nm for the LCO SL. This result is consistent with the observation that the dark stripes, which are believed to be closely related to the magnetic order, remain clear in the MLs while they are vague in the corresponding LCO SL. The present work suggests a novel route to tune the magnetism of perovskite oxide films.

Cd 1-x Ni x O ceramics were synthesized by the conventional solid state reaction method and the effect of Ni doping on the thermoelectric performance of CdO was investigated. The introduction of Ni led to dramatic changes in the electrical transport behaviors of CdO ceramics and thus an improvement in power factor, which were suggested to be related to the widening of the band gap as well as the formation of an impurity level in the band gap of CdO after the substitution of Ni 2+ for Cd 2+ . Doping of Ni also had a significant influence on the microstructure of CdO along with the development of NiO second phase when the Ni concentration exceeded 1%, which effectively suppressed the heat transfer by enhanced phonon scattering. Benefiting from the improved power factor and the reduced thermal conductivity, a high ZT of 0.43 was achieved in the Cd 0.99 Ni 0.01 O sample at about 1000 K.

Conductive colloidal probe Atomic Force-Scanning Electrochemical Microscopy (AFM-SECM) is a new approach, which employs electrically insulated AFM probes except for a gold-coated colloid located at the end of the cantilever. Hence, force measurements can be performed while biasing the conductive colloid under physiological conditions. Moreover, such colloids can be modified by electrochemical polymerization resulting, e.g. in conductive polymer-coated spheres, which in addition may be loaded with specific dopants. In contrast to other AFM-based single cell force spectroscopy measurements, these probes allow adhesion measurements at the cell–biomaterial interface on multiple cells in a rapid manner while the properties of the polymer can be changed by applying a bias. In addition, spatially resolved electrochemical information e.g., oxygen reduction can be obtained simultaneously. Conductive colloid AFM-SECM probes modified with poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) are used for single cell force measurements in mouse fibroblasts and single cell interactions are investigated as a function of the applied potential.

Numerous Au-rich deposits in the western South China Block, SW China, provide insights into the gold enrichment process at a lithospheric scale. Zhenyuan is a giant gold deposit in the western South China Block, but its genesis remains controversial with competing hypotheses of magmatic–hydrothermal and metamorphic–hydrothermal development. Here, we present new petrographic, major and trace element, and zircon U–Pb age data for quartz porphyry from the Zhenyuan deposit to evaluate the specific gold enrichment process. Zircon SHRIMP and LA–ICP–MS results demonstrate that the Zhenyuan quartz porphyries crystallized at ca. 255–247 Ma. This age is broadly consistent with the Re–Os age of gold-bearing pyrite measured in previous studies. The porphyries are characterized by high-K calc-alkaline compositions and exhibit significant enrichment in LILEs and LREEs, and strong depletion in HFSEs. They share the same source (Au-rich lower crust) with Cenozoic Au-bearing intrusions. The initial melts had a weak oxidation state (ΔFMQ = –0.15–0.55), which favored Au accumulation and migration. However, the gold was precipitated with the crystallization of Ti–Fe oxides in the middle crust, resulting in the emplacement of Au-poor magma in the upper crust. The gold orebodies in the Zhenyuan deposit formed due to Cenozoic hydrothermal processes, as evidenced by our observations of ore-bearing pyrite and Ar–Ar ages of phlogopite measured in previous studies. Combined with regional mineralization data, we propose lithosphere-scale processes for gold accumulation, migration, and precipitation from the Neoproterozoic to Cenozoic. Specifically, we predict an Au-rich middle crust beneath the western South China Block.

The interface reconstruction in perovskite heterostructures caused by interfacial octahedral tilt/rotation and its effects on the spin, charge, and orbital degrees of freedom is a very attractive topic for correlated oxides. Here, we present a systematic investigation on tensely strained (110)-LaCoO3/La2/3Sr1/3MnO3/LaCoO3 trilayers, focusing on orbital reconstruction and accompanied effects. The most remarkable finding is the reordering of the energy levels of Mn-3d orbitals at the interface: the low-lying orbital becomes dx2-y2 for sandwiched La2/3Sr1/3MnO3 rather than d3z2-r2 as expected for a bare La2/3Sr1/3MnO3 film. Interlayer charge transfer via dx2-y2 orbitals is further detected as a driving force of orbital reconstruction. Due to spin–orbit coupling, the charge/orbital reconstruction produces a chain effect on the spin degree of freedom of the La2/3Sr1/3MnO3 layer, resulting in a dramatic spin reorientation by 90° in a film plane. The present work demonstrates how to tune macroscopic properties of correlated oxides via mutual coupling between different degrees of freedom.

The adaptive behaviour and thermal responses of building occupants can be responsible for significant uncertainties when comparing monitored and modelled building energy performance. A better understanding of the interaction of occupants and their buildings is necessary for managing this uncertainty and reducing discrepancies between predicted and actual energy use (commonly known as ‘the performance gap’). This paper presents the results from a longitudinal study during a summer season of ten mixed-mode offices located in Harbin, a city in northern China, which experiences severe winters and warm summers. The study collected data from on-line daily surveys, field measurements of the local environment, occupants' experiences and adaptive control behaviours. Occupant-building interactions were analysed through observing adaptive behaviour, perceived thermal sensations in the physical environment, architectural geometric variables and personnel characteristics. The driving mechanisms for behaviours and feelings were also studied. The results showed a high probability of window opening for both day and night, and a high frequency of the use of a mix of cooling options, including fans and air conditioning, accompanied by natural ventilation in the summer season. The active interaction of the offices' internal environments with the outdoor environment motivated more connections of occupant thermal feelings with the outdoor physical variables. Relative humidity levels were potential key predictors for window opening, and the geometric parameters of offices, occupants' fan use and perceived thermal feelings also showed a level of predictive ability. Evaluating the nature of occupant feelings and behaviours interactions may inform and improve results from building performance-based design.

Two-dimensional electron gases (2DEGs) at oxide interfaces, which provide unique playgrounds for emergent phenomena, have attracted increasing attention in recent years. While most of the previous works focused on the 2DEGs at ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ interfaces, here we report on a new kind of 2DEGs formed between a magnetic insulator EuO and a high-$k$ perovskite ${\mathrm{KTaO}}_{3}$. The 2DEGs are not only highly conducting, with a maximal Hall mobility of $111.6\text{ }\text{ }{\mathrm{cm}}^{2}/\mathrm{V}\text{ }\mathrm{s}$ at 2 K, but also well spin polarized, showing strongly hysteretic magnetoresistance up to 25 K and well-defined anomalous Hall effect up to 70 K. Moreover, unambiguous correspondences between the hysteretic behaviors of 2DEGs and the EuO layer are captured, suggesting the proximity effect of the latter on the former. This is confirmed by the results of density-functional theory calculations: Through interlayer exchange, EuO drives the neighboring ${\mathrm{TaO}}_{2}$ layer into a ferromagnetic state. The present work opens new avenues for the exploration for high performance spin-polarized 2DEGs at oxide interfaces.

Cell adhesion on conducting polymers is important in organic bioelectronics, including applications such as electronically switchable surfaces and electrochemical transistors. There is a fundamental interest in understanding the conducting polymer–cellular interface though as yet no direct measurements to quantify the cell adhesion forces and energies, particularly at the molecular level, have been undertaken. Here, the authors apply electrochemical-single cell force spectroscopy (EC-SCFS) to directly quantify the de-adhesion forces between single L929 fibroblast cells and polypyrrole doped with dodecylbenzene sulfonate (PPy–DBSA) under electrical stimulation. The EC-SCFS reveals single cell de-adhesion forces of 0.65 nN on PPy–DBSA films with adsorbed fibronectin (FN) protein. Blocking experiments by introducing antibodies show that cell de-adhesion is largely due to the binding (∼60% of interactions) of cell-surface α5β1 integrin receptors. Electrochemical oxidation and reduction of PPy–DBSA during initial adsorption of fibronectin cause a significant decrease in the single cell de-adhesion forces to ∼0.4 nN, which is suggested to relate to electrical stimulation effects on reducing FN adsorption on the polymer. In contrast, when electrical stimulation is applied after protein adsorption is established and during the EC-SCFS measurements, the single cell de-adhesion is significantly enhanced on the oxidized polymer compared to the reduced and nonbiased polymer. The study highlights the use of EC-SCFS to directly quantify cell adhesion on electrode surfaces, as well as the ability to probe molecular-level interactions such as integrin receptor–FN complexes with forces of ∼50–100 pN.

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.

Spin-polarized two-dimensional electron gas (2DEG) at the interface of two insulating perovskite oxides has been a focus of intensive studies in recent years. So far all attempts to construct magnetic 2DEG are based on the selection of an appropriate buffer layer or cap layer in $\mathrm{SrTi}{\mathrm{O}}_{3}$-based heterostructures, and the magnetic effect thus produced on 2DEG is indirect and weak. Here, we fabricated the 2DEG based on Fe-doped $\mathrm{SrTi}{\mathrm{O}}_{3}$ that is superparamagnetic rather than diamagnetic like $\mathrm{SrTi}{\mathrm{O}}_{3}$. In addition to good metallicity, considerable Kondo effect, and negative magnetoresistance, the most striking observation of the present work is the occurrence of the anomalous Hall effect up to room temperature. This is transport evidence for the existence of spin-polarized 2DEG at high temperatures. As suggested by the monotonic increase of Curie temperature with carrier density, the magnetic exchange between magnetic ions could be mediated by the itinerant electrons of the 2DEG. The present work opens an avenue for the exploration of spin-polarized 2DEG.

Topological crystalline insulator (TCI) is a recently-discovered topological phase of matter. It possesses multiple Dirac surface states, which are protected by the crystal symmetry. This is in contrast to the time reversal symmetry that is operative in the well-known topological insulators. In the presence of a Zeeman field and/or strain, the multiple Dirac surface states are gapped. The high-Chern-number quantum anomalous Hall (QAH) state is predicted to emerge if the chemical potential resides in all the Zeeman gaps. Here, we use molecular beam epitaxy to grow 12 double layer (DL) pure and Cr-doped SnTe (111) thin film on heat-treated SrTiO3 (111) substrate using a quintuple layer of insulating (Bi0.2Sb0.8)2Te3 topological insulator as a buffer film. The Hall traces of Cr-doped SnTe film at low temperatures display square hysteresis loops indicating long-range ferromagnetic order with perpendicular anisotropy. The Curie temperature of the 12DL Sn0.9Cr0.1Te film is ~ 110 K. Due to the chemical potential crossing the bulk valence bands, the anomalous Hall resistance of 12DL Sn0.9Cr0.1Te film is substantially lower than the predicted quantized value (~1/4 h/e2). It is possible that with systematic tuning the chemical potential via chemical doping and electrical gating, the high-Chern-number QAH state can be realized in the Cr-doped SnTe (111) thin film., 20 pages, 5 figures, accepted by Phys. Rev. B

Chemical redox reaction can lead to a two-dimensional electron gas (2DEG) at the interface between a TiO2-terminated SrTiO3 (STO) substrate and an amorphous LaAlO3 (a-LAO) capping layer. When replacing the STO substrate with rutile and anatase TiO2 substrates, considerable differences in interfacial conduction are observed. Based on X-ray photoelectron spectroscopy (XPS) and transport measurements, we conclude that the interfacial conduction comes from redox reactions, and that the differences among the materials systems result mainly from variations in the activation energies for the diffusion of oxygen vacancies at substrate surfaces.

The tunability of topological surface states and controllable opening of the Dirac gap are of great importance to the application of topological materials. In topological crystalline insulators (TCIs), crystal symmetry and topology of electronic bands intertwine to create topological surface states and thus the Dirac gap can be modulated by symmetry breaking structural changes of lattice. By transport measurement on heterostructures composed of p-type topological crystalline insulator SnTe and n-type conventional semiconductor PbTe, here we show a giant linear magnetoresistance (up to 2150% under 14 T at 2 K) induced by the Dirac Fermions at the PbTe/SnTe interface. In contrast, PbTe/SnTe samples grown at elevated temperature exhibit a cubic-to-rhombohedral structural phase transition of SnTe lattice below 100 K and weak antilocalization effect. Such distinctive magneto-resistance behavior is attributed to the broken mirror symmetry and gapping of topological surface states. Our work provides a promising application for future magneto-electronics and spintronics based on TCI heterostructures., Comment: 16 pages of text including four figures

This paper aims to develop an artificial neural network (ANN) to predict the energy consumption and cost of cross laminated timber (CLT) office buildings in severe cold regions during the early stage of architectural design. Eleven variables were selected as input variables including building form and construction variables, and the values of input variables were determined by local building standards and surveys. ANNs were trained by the simulation data and Latin hypercube sampling (LHS) method was used to select training datasets for the ANN training. The best ANN was obtained by analyzing the output variables and the number of hidden layer neurons. The results showed that the ANN with multiple outputs presented better prediction performance than the ANN with single output. Moreover, the number of hidden layer neurons in ANN should be greater than five and preferably 10, and the best mean square error (MSE) value was 1.957 × 103. In addition, it was found that the time of predicting building energy consumption and cost by ANN was 80% shorter than that of traditional building energy consumption simulation and cost calculation method.