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The effects of Cr coating, deposited by chemical vapor deposition, on the creep properties of Zr-4 alloy and the results for its stability during long-time service were reported. Its microstructure was studied by scanning electron microscopy, electron probe microanalysis, and electron backscatter diffraction. Results show that the grains of the Zr-4 matrix were equiaxed, exhibiting 〈0001〉 texture parallel to the normal direction (〈0001〉//ND). Moreover, after the creep test, coated samples displayed a lower number of subgrain boundaries within their matrix compared with uncoated samples. Thus, the application of a Cr coating is instrumental in minimizing the stress on Zr-4, ultimately contributing to an enhancement in creep resistance of the coated samples. The Cr coating exhibits a high stability during long-term diffusion test. The coating cracks at a minimum stress of 157 MPa at 350 °C and 137 MPa at 400 °C. The Monkman–Grant relationship between the steady-state creep rate and creep fracture time was derived using a systematic summary of data pertaining to creep fracture.

E-skins, capable of responding to mechanical stimuli, hold significant potential in the field of robot haptics. However, it is a challenge to obtain e-skins with both high sensitivity and mechanical stability. Here, we present a bioinspired piezoresistive sensor with hierarchical structures based on polyaniline/polystyrene core–shell nanoparticles polymerized on air-laid paper. The combination of laser-etched reusable templates and sensitive materials that can be rapidly synthesized enables large-scale production. Benefiting from the substantially enlarged deformation of the hierarchical structure, the developed piezoresistive electronics exhibit a decent sensitivity of 21.67 kPa–1and a subtle detection limit of 3.4 Pa. Moreover, an isolation layer is introduced to enhance the interface stability of the e-skin, with a fracture limit of 66.34 N/m. Furthermore, the e-skin can be seamlessly integrated onto gloves without any detachment issues. With the assistance of deep learning, it achieves a 98% accuracy rate in object recognition. We anticipate that this strategy will render e-skin with more robust interfaces and heightened sensing capabilities, offering a favorable pathway for large-scale production.

In this article, a multifunctional polarization conversion metasurface (MPCM) has been proposed that can switch between seven different transmissive and reflective polarization conversion modes. The basic unit cell consists of three layers of split square rings (SSRs) separated by two substrates, and a P-I-N diode is embedded in the top SSR to dynamically control asymmetric transmission and reflection responses. The layer-by-layer design guideline is provided with the polarization conversion mechanism illustrated. A prototype made up of $20\times 20$ units was fabricated and measured. The measurement and simulation results demonstrate the versatile polarization conversions including copolarization reflection, cross-polarization transmission, and circular polarization reflection and transmission, depending on the incident $x$ - and $y$ -polarized waves forward and backward. Significantly, the performance of the MPCM keeps excellent in a large oblique angle range of 50°. The MPCM synthesized from the single SSR layers provides an idea for general transmissive and reflective metasurface design, which is expected to be applied in the fields of radar and wireless communications.

In order to satisfy the robotic personalized service requirements that can select exclusive items to perform inference and planning according to different service individuals, the service robots need to have the ability to independently obtain the ownership relationship between humans and their carrying items. In this work, we present a novel semantic learning strategy for item ownership. Firstly, a human-carrying-items detection network based on human posture estimation and object detection model is used. Then, the transferred convolutional neural network is used to extract the characteristics of the objects and the back-end classifier to recognize the object instance. At the same time, the face detection and recognition model are used to identify the service individual. Finally, on the basis of the former two, the active learning of ownership items is completed. The experimental results show that the proposed ownership semantic learning strategy can determine the ownership relationship of private goods accurately and efficiently. The solution of this problem can improve the intelligence level of robot life service.

When there are outliers or heavy-tailed distributions in the data, the traditional least squares with penalty function is no longer applicable. In addition, with the rapid development of science and technology, a lot of data, enjoying high dimension, strong correlation and redundancy, has been generated in real life. So it is necessary to find an effective variable selection method for dealing with collinearity based on the robust method. This paper proposes a penalized M-estimation method based on standard error adjusted adaptive elastic-net, which uses M-estimators and the corresponding standard errors as weights. The consistency and asymptotic normality of this method are proved theoretically. For the regularization in high-dimensional space, the authors use the multi-step adaptive elastic-net to reduce the dimension to a relatively large scale which is less than the sample size, and then use the proposed method to select variables and estimate parameters. Finally, the authors carry out simulation studies and two real data analysis to examine the finite sample performance of the proposed method. The results show that the proposed method has some advantages over other commonly used methods.

The widespread use of polymer materials and their improper disposal have resulted in significant environmental pollution and wastage of resources. Therefore, the design of chemically recyclable, environmentally compatible, and applicable polymers represents a new approach for a green and circular polymer economy, and it has become a major focus worldwide. Herein, we efficiently synthesized a seven-membered ether lactone, 3,4-dihydro-2H-benzo[b][1,4]dioxepin-2-one (BDXO), through a one-step reaction and successfully realized its controlled ring-opening polymerization (ROP). The ROP of BDXO in bulk and solvent conditions catalyzed by Sn(Oct)2was investigated systematically, and the thermodynamic parameters obtained were ΔSP0= −30.90 J·mol–1·K–1and ΔHP0= −14.52 kJ·mol–1. The PBDXO polymer exhibits excellent thermal properties, applicable mechanical properties, excellent biocompatibility, and complete hydrolytic degradability. Notably, not only was the direct chemical recycling of PBDXO to BDXO monomer realized with high efficiency through bulk thermal depolymerization with a yield greater than 92% and a purity of up to 96% but also the regenerated PBDXO with almost the same structure and properties as the initial PBDXO was obtained through repolymerization of the recycled BDXO, establishing a polymer–monomer–polymer closed-loop life cycle.

Advanced flexible electronic devices make urgent demand for wearing comfort and data accuracy. Piezoelectric composites exhibit great potential, but mutually constrained mechanical strength and electrical output limit their further applications. Here, we design a gradient PMN-PT/PVDF nanocomposite viaa non-equilibrium process integrated with a modified electrospinning and hot-pressing process to modulate the piezoelectric output and mechanical strength. The enhanced piezoelectric output together with the mechanical strength of the gradient structure are verified from both the experimental and simulation results. Ascribed to a unique three-dimensional gradient distribution, the prepared PMN-PT/PVDF nanocomposite exhibits an excellent mechanical strength (830 MPa) and piezoelectric performance (1.08 V), which are substantially higher than those of a randomly dispersed nanocomposite. The enhancement mechanism is revealed in terms of polarization, stress and crystallinity. These results of the gradient structure offer new opportunities to understand the structure-related mechanical and electrical behaviors of a nanocomposite, and support the design of a nanocomposite with overall performance.

As an important extension of the varying-coefficient model, the partially linear varying-coefficient model has been widely studied in the literature. It is vital that how to simultaneously eliminate the redundant covariates and separate the varying and nonzero constant coefficients for varying-coefficient models. In this paper, we consider the penalized composite quantile regression to explore the model structure of ultra-high-dimensional varying-coefficient models. Under some regularity conditions, we study the convergence rate and asymptotic normality of the oracle estimator and prove that, with probability approaching one, the oracle estimator is a local solution of the nonconvex penalized composite quantile regression. Simulation studies indicate that the novel method as well as the oracle method performs in both low dimension and high dimension cases. An environmental data application is also analyzed by utilizing the proposed procedure.

Graphical Abstract:

Effective tuning of nanoscale domain structures provides fundamental basis for controlling and engineering of various functionalities in ferroelectric materials. In this work, we demonstrate the precise patterning of nanoscopic domain structures in as-grown epitaxial PbTiO3(PTO) films by merely introducing an ultrathin pre-patterned doping layer (e.g., Fe-doped PTO). The doping layer can effectively reverse the interfacial built-in bias, consequent to a reversed initial polarization reorientation in the as-grown film, which makes it possible to transfer the nano-patterns in the doping layer into the domain structure of ferroelectric films. For instance, we have successfully fabricated large area ordered array of nanoscale cylindrical domains (downward polarization) embedded in the matrix domain with opposite polarization (upward polarization) in PTO film. These nanoscale cylinder domains also allow deterministic and reversible erasure and creation induced by biased tip scanning. The results provide an effective pathway for on-demand patterning of large area nanoscale domains in the as-grown films, which may find applications in a wide range of nanoelectronic devices.

Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains (H5-Re11 and H5-Re12) used in China. In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production. The vaccine strain H5-Re13 contains the hemagglutinin (HA) and neuraminidase (NA) genes of an H5N6 virus that bears the clade 2.3.4.4h HA gene, H5-Re14 contains the HA and NA genes of an H5N8 virus that bears the clade 2.3.4.4b HA gene, and H7-Re4 contains the HA and NA genes of H7N9 virus detected in 2021. We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese. The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested. Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses (an H5N1 virus, an H5N6 virus, and an H5N8 virus) bearing the clade 2.3.4.4b HA gene, an H5N6 virus bearing the clade 2.3.4.4h HA gene, and an H7N9 virus. All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses. Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4h or 2.3.4.4b HA gene was observed in ducks and geese. Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7N9 viruses that are currently circulating in nature.

Flexoelectric and photo-flexoelectricity are scientifically intriguing and hold considerable potential for various applications such as soft strain sensing, photovoltaics, energy harvesting, etc.Among flexoelectric materials, freestanding ferroelectric thin films are believed to have huge flexoelectricity and tunability due to their excellent lattice regulatory freedom and sustainability to larger strain gradients. In this work, we demonstrated a freestanding BiFeO3(BFO) thin film-based soft strain sensor and explored their flexoelectric coefficient and flexoelectric photovoltaic effect under different strain gradients. Under different bending scales, the photocurrent of the thin film exhibits a step-like variation, indicating that the sensor can measure strain gradient with high sensitivity. These results show the potential application of freestanding ferroelectric films in flexible devices.

Zinc oxide (ZnO), as a typical piezoelectric semiconductor, has gained significant attention in the field of wearable electromechanical coupling. However, the presence of an intrinsic screening effect becomes a bottleneck in developing high-performance ZnO-based piezoelectric devices. To address this limitation, we propose the formation of p-n homojunction by La doping in ZnO nanorods (NRs) as well as discrete structural design to improve their electrical output and flexibility. The enhanced performance and the mechanism behind it are explored and revealed in terms of morphology, structure, built-in electric field, depletion layer width, and junction capacitance, respectively. Benefitting from the excellent electromechanical coupling performance of the developed devices, different human motions can be recognized and classified with the aid of machine learning. These findings provide a new insight into the impact of doping on the output performance of piezoelectric semiconductor devices, thus facilitating advancements in piezoelectric device design and application exploration.

In the past decade, there has been extensive global surveillance for highly pathogenic avian influenza (HPAI) infection in both animals and humans, however, few studies on epidemiology of avian influenza in Democratic People's Republic of Korea (DPRK) were published. During the period 2013–2014, HPAI H5N1 viruses were detected with outbreaks in domestic poultry in DPRK. Phylogenetic analysis revealed that the hemagglutinin gene of all samples belonged to clade 2.3.2.1c with high homology. The HPAI H5N1 virus found in ducks at the Tudan Duck Farm in 2013 was might introduced by migratory birds and then led to the outbreaks on neighboring chicken farms in 2014. These data provide direct evidence for the transmission of avian influenza viruses from wild birds to waterfowl to terrestrial birds. Therefore, the monitoring and control of influenza virus in ducks must be given top priority, which are essential components to prevent and control HPAI.

In order to improve the plasticity of the Al–Mg alloy, which fabricated by continuous casting and rolling, the alloy was heat treated at 370 °C, 400 °C, 430 °C and 460 °C for 2 hours and cooled with the furnace. The microstructure and mechanical properties of heat-treated Al–Mg alloy under different heat treatment temperatures were analyzed. The results show that the columnar grains begin to disappear at heat treatment temperature of 460 °C. The size of equiaxed grains begins to increase as the heat treatment temperature increases. The tensile strength of the alloy decreases with the increase of heat treatment temperature and the Brinell hardness increases when the heat treatment temperature is between 370-430 °C. At heat treatment of 430 °C, the elongation and the Brinell hardness of the alloy reached to 42.91% and 70.5 HB, respectively.

Recently, there is a surge of research interest in configurable ferroelectric conductive domain walls which have been considered as possible fundamental building blocks for future electronic devices. In this work, by using piezoresponse force microscopy and conductive atomic force microscopy, we demonstrated the controlled manipulation of various conductive domain walls in epitaxial BiFeO3thin films, e.g.neutral domain walls (NDW) and charged domain walls (CDWs). More interestingly, a specific type of nanoscale domains was also identified, which are surrounded by highly conductive circular CWDs. Similar nanoscale domains can also be controlled created and erasured by applying local field via conductive probe, which allow nondestructive current readout of different domain states with a large on/off resistance ratio up to 102. The results indicate the potential to design and develop high-density non-volatile ferroelectric memories by utilizing these programable conductive nanoscale domain walls.

Deep-blue metal halide perovskite light-emitting diodes (PeLEDs) (450–470 nm) still fall behind their green and red counterparts in terms of efficiency, luminance, and lifetime, badly suffering from excess intrinsic surface defects of metal halide perovskites. Herein, we presented a liquid nitrogen passivation (LNP) strategy to effectually restrain the defects of surface Br vacancy (VBr) for high-quality deep-blue MAPbBr3quantum dots (QDs). This liquid nitrogen (LN) provides a low-temperature environment to reduce the size of MAPbBr3QDs for the green-to-deep-blue emission transformation and impel NH4Br to firmly anchor surface Br ions for VBrpassivation. These irreversible deep-blue MAPbBr3QDs remarkably feature the high photoluminescence quantum yield of 97.64% and the strong stability of 91% remaining photoluminescence intensity against ultraviolet irradiation after 120 min, which are comparable to those of red/green counterparts. Based on these findings, we developed deep-blue PeLEDs with the electroluminescence emission of 455 nm, which is in line with the standard of the National Television Standards Committee (NTSC). Evidently, this LNP strategy may open a way to transform the emission spectra and achieve high-quality deep-blue perovskite QDs, promoting the commercial development of deep-blue PeLEDs.

Aiming to better understand the physiochemical properties of lignite, we select Zhaotong lignite as object and adopt simulation and experiment data to construct its molecular structure. Firstly, the important parameters including carbon skeleton, valence state and functional group of the sample are obtained by ultimate analysis, 13C NMR, XPS and Py-GC/MS. Results indicate that the ratio of aromatic carbon and aromatic bridge carbon to surrounding carbon of the sample are 40.32% and 0.14, respectively. Such results imply that the aromatic structure of the sample is dominated by benzene and naphthalene. Moreover, the ratio of aliphatic carbon is 51.55%, and the aliphatic structure is mainly comprised by methyl, methylene, quaternary carbon and oxygen-aliphatic carbon. Oxygen atoms principally exist in ether, carbonyl and carboxyl groups, of which ether accounts for 70.2%. Additionally, the contents of pyridine, pyrrole and quaternary nitrogen are 25.2%, 46.3% and 13.0%, respectively. Based on the aforementioned results, the molecular structure model of Zhaotong lignite is constructed by the method of computer-aided molecular design. Subsequently, the molecular formula of Zhaotong lignite is calculated as C183H211O55N4. Finally, in order to verify the reasonability of the constructed model, the 13C NMR of the molecular structure model is simulated by employing the basis set of GIAO/6–31G at the Gaussian 09 computing platform. These simulated results agree well with the experimental ones, which suggests that the molecular structure model of Zhaotong lignite is accurate and reasonable.

The conversion of COxinto value-added green aromatics is considered as a promising route to achieve the world's decarbonization due to its considerable thermodynamic driving force and atomic economy where low H/C ratio aromatics are chosen as a product. It is enabled by bifunctional nano-catalysts composed of metal oxides with abundant oxygen vacancies and acid zeolites, thus realizing superior selectivity in hydrocarbons at the single pass of COxconversion. In this mini-review, we mainly provide some thought-provoking insights at the nanoscale of this complicated process including the proximity of active sites, reaction mechanism, asymmetric desorption behavior of intermediates and final products and overall thermodynamic analysis. The facile surface diffusion of intermediates owing to the proximity of active sites stimulates the reaction, which follows an autocatalytic process. This positive feedback attributed to the autocatalytic cycle accelerates the transformation of energy and materials in the thermodynamically optimal direction, making the reaction highly selective towards the final products. This complicated coupling process, like a nano-maze constituted by these micro-environment factors, is complicated in terms of the reaction pathway but highly selective to a fixed direction guided by overall thermodynamics. Deep understanding of such an autocatalytic cycle at the nanoscale paves the way for the rational design of next-generation high-performance catalysts.

The indoor robots are expected to complete metric navigation tasks safely and efficiently in complex environments, which is the essential prerequisite for accomplishing other high-level operation tasks. 2D occupancy grid maps are sufficient to support the robots in avoiding all obstacles in the environments during navigation. However, the maps based on normal laser scans only reflect a horizontal slice of the environment, which may cause the problem of some obstacles missing or misinterpreting their exact boundaries, thereby threatening the safety and efficiency of robot navigation. This paper presents a 2D mapping method based on virtual laser scans to provide a more comprehensive representation of obstacles for indoor robot navigation. The resulting maps can accurately represent the top-down projected contours of all obstacles no matter where their vertical positions are. The virtual laser scans are initially generated from raw data of an RGB-D camera based on the filtering, projection, and polar-coordinate scanning. The scans are fed directly to the laser-based simultaneous localization and mapping (SLAM) algorithms to update the current map and robot position. Two auxiliary strategies are proposed to further improve the quality of maps by reducing the impact of the narrow field of view and the blind zone of the RGB-D camera on the observations. In this paper, the improved virtual laser generation method makes the extracted 2D observations fit the laser-based SLAM algorithms, and two auxiliary strategies are novel ways to improve map quality. The generated maps can reflect the comprehensive obstacle information in indoor environments with good accuracy. The comparative experiments are carried out based on four simulation scenarios and three real-world scenarios to prove the effectiveness of our 2D mapping method.

The naturally microstructure-bioinspired piezoresistive sensor for human–machine interaction and human health monitoring represents an attractive opportunity for wearable bioelectronics. However, due to the trade-off between sensitivity and linear detection range, obtaining piezoresistive sensors with both a wide pressure monitoring range and a high sensitivity is still a great challenge. Herein, we design a hierarchically microstructure-bioinspired flexible piezoresistive sensor consisting of a hierarchical polyaniline/polyvinylidene fluoride nanofiber (HPPNF) film sandwiched between two interlocking electrodes with microdome structure. Ascribed to the substantially enlarged 3D deformation rates, these bioelectronics exhibit an ultrahigh sensitivity of 53 kPa–1, a pressure detection range from 58.4 to 960 Pa, a fast response time of 38 ms, and excellent cycle stability over 50 000 cycles. Furthermore, this conformally skin-adhered sensor successfully demonstrates the monitoring of human physiological signals and movement states, such as wrist pulse, throat activity, spinal posture, and gait recognition. Evidently, this hierarchically microstructure-bioinspired and amplified sensitivity piezoresistive sensor provides a promising strategy for the rapid development of next-generation wearable bioelectronics.

The limitation of commercial single-crystal substrates and the lack of continuous strain tunability preclude the ability to take full advantage of strain engineering for further exploring novel properties and exhaustively studying fundamental physics in complex oxides. Here, we report an approach for imposing continuously tunable epitaxial strain in oxide heterostructures beyond substrate limitations by inserting an interface layer through tailoring of its gradual strain relaxation. Taking BiFeO3as a model system, we demonstrate the introduction of an ultrathin interface layer that allows the creation of desired strain states that can induce phase transition and stabilize a super-tetragonal phase as well as morphotropic phase boundaries, overcoming substrate limitations. Continuously tunable strain from tension to compression can be generated by precisely adjusting the interface layer thickness, enabling the achievement of continuous orthorhombic–rhombohedral-like–tetragonal-like phase transition. This proposed route could be extended to other oxide heterostructures, providing a platform for creating exotic phases and emergent phenomena.

Two multidrug-resistant (MDR) mcr-1-harboring Klebsiella pneumoniaeisolates from patients with urinary tract infections and one MDR Klebsiella quasipneumoniaeisolate from a patient with bloodstream infection were identified to carry tmexCD1-toprJ1. The addition of the efflux pump inhibitor reduced the tigecycline MIC against all three isolates by 8- to 16-fold. pKQBSI104-1 was transferred from K. quasipneumoniaeto Escherichia coliJ53 via conjugation.

Aeromonas dhakensisis an important ubiquitous Gram-negative and freshwater bacterium detected in different reservoirs. It can cause invasive diseases in humans. Herein, we report the first case in Mainland China of a fulminant death of a 29-year-old man as a result of a new, unexpected association between septicemic A. dhakensisand hepatitis B viral infection (HBV). Herein, the patient died from multiple organ failure 5 d postadmission after the ingestion of Snakehead Fish meal. The isolated bacterium was initially misidentified as Aeromonas hydrophilausing VITEK-2, while whole-genome sequencing (WGS) revealed that the isolate is A. dhakensis. WGS revealed the occurrence of three antimicrobial genes of resistance: imiH, cphA2, and blaOXA-12; besides, major virulence factors were detected. In silico, multilocus sequence typing (MLST) showed that our A. dhakensis17FW001 belonged to a novel sequence type (ST557). A comparative genomic analysis of our isolate with nine selected Aeromonasspecies was done, which elucidated the pathogenicity of our A. dhakensis. In conclusion, we reported for the first time the association between A. dhakensisand HBV in Mainland China. We revealed that septicemic A. dhakensiscould result in severe adverse clinical outcomes that end up with unexpected fulminant death especially when it is accompanied with HBV and sheds light on the virulence of A. dhakensisand the high rate of its misdiagnosis that requires to urgently consider screening of all cases of A. dhakensisfor HBV in the future. Besides, caution should be taken while dealing with snakeheads which act as a vector for A. dhakensis.

Percutaneous liver biopsy (LB) has been considered the reference standard in distinguishing the degree of liver disease, but there has been no definitive systematic review to assess complication rates or potential risk factors for them. In this study, we searched the PubMed, Embase, Web of Science, and Scopus databases for studies appraising complication rates after percutaneous ultrasound (US)‐guided LB published until October 11, 2018. The safety and efficacy of US‐guided LB were estimated according to major and minor complications. Subgroups including the biopsy style, needle styles, mean number of needle insertions, study period, and specific complication items were analyzed. Among 12,481 patients from 51 studies, pooled results showed a low rate (0; 95% confidence interval, 0–0) of major and minor complications. The subgroup analysis indicated that US‐guided LB had a low major complication rate of 0 (0–0) for both fine‐needle aspiration and core biopsy, with rates of 0.016 (0–0.032) for 14‐gauge, 0.010 (0.003–0.017) for 15‐gauge, 0.002 (–0.001–0.005) for 20‐gauge, and 0 (0–0) for 16‐, 17‐, 18‐, 21‐, and 22‐gauge needles, and low minor complication rates of 0 (0–0) for fine‐needle aspiration and 0.001 (0–0.002) for core biopsy, with rates of 0.164 (0.137–0.191) for 15‐gauge, 0.316 (0.113–0.519) for 16‐gauge, and 0 (0–0) for 14‐, 17‐, 18‐, 20‐, 21‐, and 22‐gauge needles. Furthermore, specific complication rates of bleeding, pain, pneumothorax, vasovagal reactions, and death were all 0 (0–0). These findings suggest that it is possible to safely perform percutaneous US‐guided LB.

The potential screening effect of one-dimensional ZnO nanorods from carriers has been theoretically proved to severely limit its piezoelectricity, but its exact mechanism needs to be further revealed in experiments to guide the design of piezoelectric semiconductors. Here, a discretely structured design was proposed to prevent the free carriers from tunneling among adjacent ZnO nanorods for suppressing the screening effect. Piezoresponse force microscope and finite element analysis were employed in combination to uncover the underlying mechanism in experiment. Further, the output voltage of this discretely structured device was 1.62 times higher than that of the nondesigned device, which clearly authenticates this suppression behavior. Besides, this design prompts an unexpected improvement in flexibility, where the flexural modulus of this piezo-film was reduced by 35.74%. Notably, this work opens a new way to understand the potential screening effect, as expected, and to advance the development of piezo-electronics toward better piezoelectricity and more excellent flexibility.

When zirconium alloy is corroded, an oxide film is formed on the surface, which hinders the ion transfer during the corrosion process. Therefore, the analysis of the oxide film is an important part of the research on the corrosion resistance of zirconium alloys. In this paper, two kinds of Zr-Sn-Nb alloys were corroded in 400 °C/10.3 MPa pure steam and 500 °C/10.3 MPa pure steam in autoclave to obtain samples with oxide thickness of 14 um and 18 um respectively. Then they were annealed at 800 °C at a pressure of 10-4 Pa for 18 h. XRD and WDS studies were used to analyze the structure and oxygen content of the oxide film after annealing. The results indicate that the oxide films of alloys change from zirconium dioxide to zirconium after annealing. The oxygen diffuses into the substrate and its content decreases continuously with increasing diffusion distance. Combined with the SEM analysis of cross-section samples, it is found that the annealed samples are composed of several layers. An oxygen-saturated zirconium layer, a transitional layer with micro-cracks, an oxygen-dissolved α-Zr layer and a β-Zr layer are identified. Based on these results, the mechanism of the ion transfer in the oxide film during annealing is analyzed deeply. It is proposed that space charges in the oxide film have a major impact on deoxidation kinetics. This study provides a new research method for the corrosion mechanism of zirconium alloys.