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Abstract: Tungsten-trioxide (WO3) and lanthanum oxide (La2O3)-added WO3 nanoparticles were successfully prepared by sol–gel method. The structure and morphological characteristics of the nanopowders were studied by means of field-emission SEM (FE-SEM). The results showed that all the nanopowders of spherical shape with average size smaller than 40nm have good dispersivity. The effect of La2O3 on the gas response of the samples was investigated, especially the volatile organic compound (VOC) gases. The highest gas response of La2O3-added WO3 is found to shift to low temperature, compared to that of the pure WO3. Analysis with FE-SEM revealed that, compared with the pure WO3, La2O3-added WO3 has a smaller average grain size but greater surface area. Complex impedance spectroscopy analysis indicated an increase in grain boundary resistance. [Copyright &y& Elsevier]

Abstract: Nano-scaled tungsten-trioxide (WO3) powder has been synthesized by sol–gel process using tungsten powders. The effect of cerium oxide (CeO2) additive on the gas response of the samples was investigated, especially to the volatile organic compound (VOC) gases, and significant enhancement was achieved. The highest gas response of Ce-added WO3 samples was found to shift to lower temperatures, compared to the pure WO3 ones. The analysis with field-emission SEM reveals that grain boundary is pinned due to adding CeO2, which results in decrease in the average grain size of Ce-added WO3 and increase in the surface area, compared with the pure WO3 ones. Complex impedance spectroscopy analysis indicates that grain boundary resistance increases and grain boundary capacitance decreases with the increasing concentration of CeO2. It means that the Ce ions exist mainly in the WO3 grain boundaries and helps to improve the microstructure. [Copyright &y& Elsevier]

Constructing an all‐in‐one wearable electronic system integrated with an energy‐harvesting, an energy‐storing, and a working unit can fundamentally solve the problems of sustainable energy supply, miniaturization, and lightweight for further commercialization. Here, an all‐in‐one wearable system consisting of solar cell, cathode‐free zinc ion micro‐battery (ZIMB) and piezoresistive pressure sensor is proposed, achieving an ultralong and stable power supply. Under the action of photocurrent, this integrated system is stimulated to in situ generate MnO2 on the initial cathode‐free substrate, meanwhile converts into chemical energy for powering the sensor, which eliminates prepreparation and treatment of the cathode for energy storage units. The facial cathode‐free ZIMB combining the all‐in‐one design enhances matching degree between different units and improves the integration. The working mechanism of the cathode‐free ZIMB is analyzed systematically through multiple ex situ characterizations and density functional theory (DFT) simulation. And the integrated sensing system illuminating for 12.0 h realizes the ultralong energy supply of the pressure sensor up to 150 000 cycles. As a concept, the integrated wearable electronic is used to detect human physiological signals, showcasing potential applications in activity monitoring, intelligent robotics, human–computer interaction, and other related fields. [ABSTRACT FROM AUTHOR]

Polycrystalline CuCr1-xNixO2 is synthesized and its multiferrocity is characterized in order to enhance the ferromagnetism and ferroelectricity of CuCrO2-based multiferroics. At the optimized doping level x=0.05, we observe not only an enhancement of one order of magnitude in magnetization but also a remarkable increasing of polarization up to ∼50 μC/m2 from ∼35 μC/m2 of polycrystalline CuCrO2. It is argued that the Ni-doping may modulate the antiferromagnetic interactions between Cr3+ ions and probably induce the conical-like spin component responsible for the enhanced ferromagnetism. [ABSTRACT FROM AUTHOR]

Polycrystalline CuCr1-xNixO2 is synthesized and its multiferrocity is characterized in order to enhance the ferromagnetism and ferroelectricity of CuCrO2-based multiferroics. At the optimized doping level x=0.05, we observe not only an enhancement of one order of magnitude in magnetization but also a remarkable increasing of polarization up to ∼50 μC/m2 from ∼35 μC/m2 of polycrystalline CuCrO2. It is argued that the Ni-doping may modulate the antiferromagnetic interactions between Cr3+ ions and probably induce the conical-like spin component responsible for the enhanced ferromagnetism. [ABSTRACT FROM AUTHOR]

Abstract: We prepare polycrystalline CuCrO2 and CuCr0.98Ni0.02O2 samples by solid state reaction and investigate their multiferroicity. It is revealed that the Ni-doping can not only enhance slightly magnetization but also improve ferroelectricity. It is argued that the Ni3+-doping destabilizes the antiferromagnetic order of Cr3+ ions and modulates the spin configuration, leading to the weak ferromagnetism and enhanced ferroelectric polarization. The coupling between the magnetic order and ferroelectric order is also characterized. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Yttrium doped ZnO thin film transistors have exhibited the superior bias stress stability. • Yttrium doping has efficiently suppressed the formation of oxygen vacancies. • Optical band gap of ZnO film is increased with Yttrium doping concentration. Abstract In this paper, we have investigated the effects of yttrium (Y) doping on the electrical performance and stability of ZnO thin film transistors (TFTs). Here, Y-doped ZnO TFTs were fabricated by using radio frequency magnetron sputtering at 150 °C. As a result, the 1% Y-doped ZnO TFT exhibits a small threshold voltage shifts of 2.5 V under positive bias stress and −2.8 V under negative bias stress as well as desirable device performance with field effect mobility of 9.8 cm2/V s, a subthreshold swing of 320 mV/decade and on/off current ratio of 107, respectively. Based on the XPS analysis and electrical characterizations, the improvement in stability and electrical properties of ZnO TFTs were attributed to the appropriate Y doping concentration, which not only could control the carrier concentration and broaden the band gap of ZnO film, but also suppress the oxygen vacancy defects and passivate the trap density at the SiO 2 /ZnO interfaces. Consequently, the high stability and excellent electrical performances of Y-doped ZnO TFTs show great potential for use in flat panel displays. [ABSTRACT FROM AUTHOR]

An experimental study on active flow control over an elliptic airfoil is performed using an alternating-current dielectric-barrier-discharge (AC-DBD) plasma actuator combined with the duty-cycled technique. This study aims to eliminate or decrease the nonlinearities of the lift curves within a range of small angles of attack at low Reynolds numbers. The results of plasma actuator characterization in the quiescent air show that the duty-cycled plasma actuation can generate periodic sustained vortices with strengthened vorticity and streamwise momentum in comparison of steady-on mode. The wind tunnel test results show that the baseline airfoil exhibits the clearer nonlinear behavior at small AOA for lower Reynolds numbers. With duty-cycled plasma actuation, a rigidly linear proportional control of the lift that varies with the AOA is achieved with the reduced frequency f + = 1 . The surface oil-flow measurement shows the plasma actuator can delay the separation and result in an enhanced lift when the laminar boundary layer separation occurs without reattachment. When the long laminar separation bubble appears in the trailing edge region, the plasma actuator can eliminate the bubble. In this case, the extra lift supplied by the bubble is eliminated, leading to a reduced airfoil lift. The linear proportional control of the lift can be achieved by the appropriate enhanced and reduced lift changes which can be supplied by the duty-cycled plasma actuation. [ABSTRACT FROM AUTHOR]

An experimental study of flow control over conical body by nanosecond pulse dielectric barrier discharge (NS-DBD) plasma actuation at Re D = 3.09 \times 10^{5} ( v = 42 m/s) is presented. First, the fundamental characteristics and control mechanisms of the plasma actuator were studied in the quiescent atmosphere. NS-DBD plasma actuator is an economical effective device because of its high discharge voltage/frequency ( \sim 20 kV/20 kHz), but short pulse duration time ( \sim 20 ns). Plasma actuators with different geometries were studied using the Schlieren technique. On the microsecond time scale, combination compression waves that consisted of a hemisphere wave and a planar wave were generated by rapid gas heating. The propagation velocity produced during the initial stage (10–40 \mu \texts ) can potentially reach the sonic level ( \sim 350 m/s). On the millisecond time scale, two starting vortices rolled up from two opposite directions, and then developed into one perturbation downstream. NS-DBD plasma actuation influences the flow by rapid localized heating and transferring energy to the near-wall gas. In the wind tunnel experiment, a pair of NS-DBD plasma actuators mounted symmetrically on the surface of the model apex were applied to control the asymmetric vortex flow field. Actuators were, respectively, aligned along the line of azimuth angles of \theta = \pm 80^\circ , ±90°, and ±100°, under positive and negative discharges. The test results include the pressure distribution sampled over the measurement station and the calculated lateral force coefficient. The efficacy of NS-DBD plasma actuation for controlling the asymmetric vortex over conical body was demonstrated with arrangements \theta = \pm 80^\circ and \theta = \pm 90^\circ . The results suggest that the actuator should be set before the suction peak point. When the flow started to accelerate and separate, the small perturbation created by NS-DBD could hardly control the flow. Pressure distributions under plasma actuation with different discharge directions indicate that the control power of NS-DBD is directional and is located along the discharge direction. The actuation with positive discharge delays the separation, whereas the actuation with negative discharge fixed separates the flow. [ABSTRACT FROM AUTHOR]

[Display omitted] • The InGaSnO thin film transistors after in-situ Ar plasma treatment enhanced the electrical performance and stability. • In-situ Ar plasma processing is simple, time-saving, and does not depend on other external equipment, reducing the thermal budget. • In-situ Ar plasma treatment reduces oxygen vacancy and interfacial defect density, reduces surface roughness, and improves film quality. High-performance InGaSnO thin film transistors are successfully fabricated with a reduced thermal budget by an in-situ Ar plasma treatment process. This process does not require external equipment for plasma treatment of the deposited film, which ensures the original vacuum environment and uses plasma energy for weak treatment. The atomic force microscope measurement shows that the surface roughness of the InGaSnO thin film decreased from 0.472 nm to 0.266 nm after treatment. The reduction of oxygen vacancy defect states is verified by the O 1s spectrum of X-ray photoelectron spectroscopy, and its interfacial defect density is also significantly reduced. The stabilities of InGaSnO TFTs are also considerably improved, with the threshold voltage shift under the negative bias stress test reduced to 0.39 V, better than annealing at 300 °C. Ar plasma treatment improves film quality and enhances device performance, which exhibits high field-effect mobility (30.8 cm2/Vs), a small sub-threshold swing (0.32 V/decade), and a low threshold voltage (−0.54 V). Overall, in-situ Ar plasma treatment not only reduces the thermal budget but also simplifies the process, enabling the utility of long-term high-temperature annealing, showing its potential in flexible display applications. [ABSTRACT FROM AUTHOR]