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Thermally-stable large strain in Bi(Mn0.5Ti0.5)O3 modified 0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3 ceramics
摘要： A N U S C RIP T (1-x)[0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3]-xBi(Mn0.5Ti0.5)O3 (x = 0 ~ 0.06, BNKMT100x) lead-free ferroelectric ceramics were prepared via solid state reaction method. Bi(Mn0.5Ti0.5)O3 induces a structure transition from rhombohedral-tetragonal morphotropic phases to pseudo-cubic phase. Moreover, the wide range of compositions within x = 0.03 ~ 0.055 exhibit large strain of 0.31% ~ 0.41% and electrostrictive coefficient of 0.027 ~ 0.041 m4/C2. Especially, at x = 0.04, the large strain and electrostrictive coefficient are nearly temperature-independent in the range of 25 ~ 100 °C. The impedance analysis shows the large strain and electrostrictive coefficient originate from polar nanoregions response due to the addition of Bi(Mn0.5Ti0.5)O3.
关键词： large strain,thermal stability,composition-insensitivity,lead-free,electric property
更新于2025-09-23 15:23:52
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High room-temperature pyroelectric property in lead-free BNT-BZT ferroelectric ceramics for thermal energy harvesting
摘要： Pyroelectrics are attracting increasing attention because they enable pyroelectric generators to extract energy from low-gradient-temperature heat for portable electronic devices. High pyroelectric coefficient around room temperature is essential for high-performance energy harvesters, which, unfortunately, is only commonly achieved in lead-based ferroelectrics. Herein we report a high room temperature pyroelectric response of 27.2 × 10-4 C m-2 K-1 in 0.94(Bi0.5Na0.5)TiO3-0.06Ba(Ti0.75Zr0.25)O3 lead-free ceramics by modulating the Zr4+/Ti4+ ratio to tune the ferroelectric-relaxor antiferroelectric-like phase transition point to around ambient temperature, whose pyroelectric response is one order of magnitude higher than that of the sample without Zr and even comparable to those of lead-containing pyroelectrics. The theoretical analysis revealed that introduced Zr4+ could incorporate into the TiO6 octahedral lattices and break the long-range translational symmetry of BaTiO3 lattices, resulting in the reduction of B-site ion displacement activation energy and transition point of ferroelectric-relaxor antiferroelectric-like phase, giving rise to a pronounced room-temperature pyroelectric effect in BNT-BZT.
关键词： BNT-BZT ceramics,Energy harvesting,Room temperature pyroelectric property,Phase transition
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 8th International Conference on Consumer Electronics - Berlin - Berlin, Germany (2018.9.2-2018.9.5)] 2018 IEEE 8th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) - Fast Rain Removal Using Rain Map and Temporal Filtering for Consumer Imaging Applications
摘要： This paper presents the severe weather image enhancement method using for consumer imaging systems. The proposed method performs the rain removal based on a rain map, which estimated by the difference among the adjacent frames. In the video frames, since the rain streaks can be regarded as the object moving in a constant direction, we can analyze the position of the rain streaks using the difference between the previous and next frames. In addition, we refine the rain map using the saturation channel in HSV color space and low-pass filtering. Experimental results show that the proposed method can provide better restored image at fast processing time compared with existing methods.
关键词： Deraining,Rain removal,Rain property
更新于2025-09-23 15:23:52
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Preparation and properties of duplex NI-P-TIO <sub/>2</sub> /NI nanocomposite coatings
摘要： Duplex Ni-P-TiO2/Ni coatings were deposited on the brass substrate by using two baths. Ni-P-TiO2 nanocomposite coatings were electroplated as the outer layer on the Ni-plated brass substrate by adding transparent TiO2 sol (0–50 mL/L) into the Ni-P plating solution. The microstructure, mechanical property and corrosion resistance of the duplex Ni-P-TiO2/Ni nanocomposite coatings were systemically investigated. The results show that the interface of duplex coating was uniform and the adhesion between two layers was extremely good. The microhardness of duplex Ni-P-12.5 mL/L TiO2 /Ni coating was ～616 HV50 compared to ～539 HV50 of Ni-P /Ni coating and ～307 HV50 of single Ni coating. Meanwhile, the wear resistance and the corrosion resistance of the duplex nanocomposite coating have also been improved remarkably compared with single Ni coating. However, adding excessive TiO2 sol (more than 12.5 mL/L) caused the agglomeration of TiO2 nanoparticles and led to a porous structure in the outer layer, resulting in the deterioration of coating properties.
关键词： Nanocomposite coatings,mechanical property,corrosion resistance.
更新于2025-09-23 15:23:52
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Enhanced Photocatalytic Activity by the Combined Influence of Ferroelectric Domain and Au Nanoparticles for BaTiO <sub/>3</sub> Fibers
摘要： Ferroelectric particles have been applied in the photocatalytic field because the spontaneous polarization results in the internal electric field, which can accelerate the separation and migration of photogenerated carriers. In this study, the BaTiO3 (BT) fibers are synthesized by electrospinning. The BT fibers calcined above 800 °C exhibit a strong ferroelectric property, which is verified by a typical butterfly-shaped displacement-voltage loop. It is found that the BT fibers with the single-domain structure exhibit better photocatalytic performance than that with the multi-domain configuration. When the single-domain transforms into multi-domain, the integrated internal electric field correspondingly breaks up, inducing that the internal electric field might cancel each other out and diminish the separation of photogenerated carriers. Also, the Au nanoparticles can improve the photocatalytic activity further on account of the surface plasmon resonance. Therefore, it is suggested that Au nanoparticles decorated on ferroelectric BT nanomaterials are promising photocatalysts.
关键词： photocatalytic performance,Ferroelectric property,domain configuration,internal electric field
更新于2025-09-23 15:23:52
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Approach to Inversion Design of Dielectric Material Based on the First-Principle
摘要： The ?rst-principle is an e?ective method for the material property calculation. One inversion design idea of dielectric material based on the ?rst-principle was put forward. In this kind of material design thought, the speci?c demanded dielectric property of material is the starting point of the whole design course. The atomic structure characteristic of the material is solved using the inversion model based on the ?rst-principle. And the key issues needing researching were discussed, these problems were quantized structure of electromagnetic and optic ?eld, the quantized polarization theory of dielectric material, the uniform calculation method of dielectric property and the dielectric material inversion model.
关键词： Dielectric material,First-principle,Dielectric property,Inversion design
更新于2025-09-23 15:23:52
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Fabrication and enhanced photocatalytic property of TiO2-ZnO composite photocatalysts
摘要： TiO2 nanotube and TiO2-ZnO composite photocatalysts were fabricated by simple hydrothermal method, and the photocatalytic property of as-prepared samples were analyzed by the photo degradation of rhodamine B water solutions under visible light irradiation. The prepared TiO2-ZnO composite photocatalysts exhibited excellent property in photo degradation of rhodamine B water solution, which is better than that of P25. The enhancement photocatalytic property of target photocatalysts could be attributed to the reduced band gap energy, the enhanced-surface physic-chemical properties, the separation of photo induced electron-hole pairs and the decreased recombination rate. In addition, TiO2-ZnO composite photocatalysts showed good stability for rhodamine B photo degradation under visible light.
关键词： Microstructure,TiO2-ZnO,Photocatalytic property,Hydrothermal method,Composite materials
更新于2025-09-23 15:23:52
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An Eco-friendly Flexible Piezoelectric Energy Harvester That Delivers High Output Performance is Based on Lead-Free MASnI3 Films and MASnI3-PVDF Composite Films
摘要： An environmentally-friendly lead-free methylammonium tin iodide (MASnI3) perovskite is successfully synthesized using a facile approach of an antisolvent-assisted collision technique under room ambient conditions, which results stability within 24 h under ambient room conditions. The phase transition of MASnI3 from tetragonal to cubic is first observed at ~ 30 °C. Polycrystalline MASnI3 films reveal a high dielectric constant of ~ 65 at 100 kHz, a low-leakage current density of 7 × 10-7 A cm-2 at 50 kV cm-1, well-developed P-E hysteresis loops, and a high piezoelectric coefficient (d33) of 20.8 pm V-1. The MASnI3 piezoelectric energy nanogenerator (PENG) shows an output voltage of ~ 3.8 V and an output current density of 0.35 μA cm-2. To enhance the piezoelectric output performance, the MASnI3 films are composited with an environmentally friendly PVDF polymer that had a porous structure. The PVDF-MASnI3 composite based-PENG reveals a maximum output voltage of ~ 12.0 V and current density of ~ 4.0 μA cm-2. A green light-emitting diode (LED) using the PVDF-MASnI3 PENGs is instantly lighted without need of a storage device, and long-term stability of the composite PENGs is validated for 90 days. This simple and cost-effective solution process is feasible for the fabrication of large-scale, high-performance, and environmental-friendly PENGs based on lead-free organic-inorganic perovskites to extensively implicate in medical and biomechanical applications.
关键词： Dielectric property,Lead-free MASnI3,PVDF-MASnI3 composite PENGs,Piezoelectric energy,Antisolvent-assisted collision technique
更新于2025-09-23 15:23:52
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Synthesis and photocatalytic properties of biomimetic morphology silicon carbide
摘要： Silicon carbide materials with bionic morphology are prepared by impregnation-calcination method using the template of leaf vein. The microstructure, element composition, and band gap of biomimetic morphology silicon carbide are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy(XPS). Photocatalytic property of biomimetic morphology silicon carbide has been measured by the dye decolorization reaction. The results demonstrate that calcination temperature has the important effect on the formation of silicon carbide. The morphology of silicon carbide can keep the original biomimetic shape of leaf vein template, and there is meosporous structure with a diameter of 2-4 nm on the interior of material. The average gain size of materials is about 16.9 nm and the specific surface area of materials is about 84.7 m2/g. After calculation, the band gap of material is 3.02 eV. For performance testing, the degradation rate of silicon carbide is 92.86% for the first time, and after the fourth repetition, the degradation rate decreased to 86.74%.
关键词： Biological Template,Silicon Carbide,Biomimetic Morphology,Photocatalytic Property
更新于2025-09-23 15:23:52
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Effect of potassium and magnesium codoping on the dielectric properties of BST powders
摘要： K and Mg codoped BST powders were prepared by a sol-gel method, and the effect of doped concentration on the dielectric performances was studied. For comparison, pure, Mg doped and K doped BST powders were studied. XRD shows all powders reveal complete diffraction peaks and ABO3 cubic perovskite polycrystalline structures. Compared to the pure BST powder, Mg doped BST powder shows a little weaker crystallization, 5%～15% K doped BST powders exhibit stronger crystallization, and the crystallization is getting stronger with increasing K doped concentrations from 2% to 15%. BST powder shows lattice parameter of 3.963 ?A, Mg doping corresponds to 3.963 ?A, 2%～20% K doping correspond to 3.963 ?A～3.967 ?A, and Mg and K codoping make lattice parameters increase from 3.967 ?A to 3.974 ?A. Mg2+ ion and K+ ion show acceptor doped mechanisms, Mg doping makes grains refine, and K doping makes grains grow. Pure BST powder and Mg doped BST powder show uniform grains with unclear grain boundaries, K doped BST powders can obtain uniform and dispersive grains with clear grain boundaries, but Mg and K codoping makes the uniformity and dispersity of the powders getting worse. Compared to pure BST powder, Mg doped BST powder shows smaller but more stable dielectric constant and dielectric loss, K doped powders tend to reveal larger and less stable dielectric constants and dielectric losses. Mg and K codoped BST powders show less than 35 dielectric constants, and lower than 0.02 dielectric losses. Dielectric properties are strongly dependent on the crystallization, doped mechanism and morphology. Mg doped and 2% Mg 2% K and 2% Mg 5% K codoped BST powders show low and stable dielectric constants and dielectric losses, thus can meet the requirements for tunable microwave applications and other applications.
关键词： dielectric property,codoping,Mg,K,BST powder
更新于2025-09-23 15:23:52