Cuixian Luo

Low-frequency and wideband vibration energy harvester with flexible frame and interdigital structure

As an alternative to traditional cantilever beam structures and their evolutions, a flexible beam based, interdigital structure, vibration energy harvester has been presented and investigated. The proposed interdigital-shaped oscillator consists of a rectangular flexible frame and series of cantilever beams interdigitally bonded to it. In order to achieve low frequency and wide-bandwidth harvesting, Young’s modulus of materials, frame size and the amount of the cantilevers have been studied systematically. The measured frequency responses of the designed device (PDMS frame, quintuple piezoelectric cantilever beams) show a 460% increase in bandwidth below 80Hz. When excited at an acceleration of 1.0 g, the energy harvester achieves to a maximum open-circuit voltage of 65V, and the maximum output power 4.5 mW.

Facile synthesis of ring-like α-Fe2O3 assembly composed of small hematite particles for highly efficient photocatalysis

A new-type of ring-like α-Fe2O3 assembly were prepared via facile top-down etching method from hematite saucer-like nanocrystals composed of small α-Fe2O3 particles. HRTEM and BET results demonstrated that the ring-like α-Fe2O3 assembly has zigzag edge and high specific surface area, which leads to higher efficient visible-light photocatalytic performance on the degradation of cationic dye Rhodamine B (RhB). UV–Vis diffuse reflectance spectra and photocurrent responses demonstrated a narrow bandgap and higher photocurrent response of ring-like α-Fe2O3 assembly, which were helpful for absorbing photons and restraint of recombination for photogenerated charges. These characters make them the promising candidates for photocatalysis.

Linear multi-degree-of-freedom low-frequency piezoelectric vibration energy harvester

ABSTRACT A linear multi-degree-of-freedom piezoelectric energy harvester has been designed in this paper. The proposed energy harvester was comprised by multi-order transmission beams and traditional single cantilever beam. As the transmission beam order increases, the resonant frequencies of this kind of harvester could be tuned and reduced efficiently. The first three modes of the three-degree-of-freedom harvester occur within the range of 0-100 Hz, reaching a fair agreement with the simulation. The operating bandwidth expands to 15 Hz, 375% of the conventional piezoelectric cantilever beam, which made this designed harvester a good candidate for energy scavenging in multi-sources and wide-frequency vibration environment.

Cu2O concave hexapod microcrystals: selective facet etching and highly improved photocatalytic performance

In this work, a unique Cu2O hexapod microcrystal with {100} facets etched concave structure has been successfully synthesized by a facile oxide etching method. Air and chloride ion were employed as etchant and shape controller agent, respectively. For the facet-selective adsorption of chloride ions on {110} and {111} planes, the oxide molecules may prefer to act on {100} facets and induced the concave structure formation, along the [100] zone axis. The {100} facets selectively etched Cu2O concave hexapod microcrystal exhibited highly improved photocatalytic activities (2.2 times) than that of basic structure, and displayed facet-dependent characteristics, which made them promising candidates for photocatalysts and sensing materials.

Concave structure of Cu2O truncated microcubes: PVP assisted {100} facet etching and improved facet-dependent photocatalytic properties

In this work, a concave structure of Cu2O truncated microcubes with {100} facet erosion has been successfully synthesized by a facile top-down etching method. Air and PVP were employed as an etchant and a shape controller agent, respectively. For the facet-selective capping of PVP on Cu2O {111} planes, the traditional relatively low energy {100} facets of Cu2O truncated microcubes would be selectively etched along their [100] zone axis in a top-down manner. The {100} facet etched Cu2O concave truncated microcubes exhibited highly improved photocatalytic activities (2.15 and 1.21 times, respectively) compared to that of the basic structure and the {111} facet etched samples on the degradation of Congo red (CR), displaying distinct facet-dependent photocatalytic characteristics, excellent stability and reusability. This work not only builds an efficient photocatalyst, but also provides a novel method to fabricate a variety of architectures with low energy facets etched and highly active crystal planes exposed, which is extremely important for the improvement of catalytic activities.

A Multiple Vibration Modes Separation Technique Based on 3*5 Element Energy Harvester Array: Frequency, Bandwidth Adjustment, and Electrical Characterization

A neat 3*5 element energy harvester array exploiting multiple vibration modes separation technique, has been designed, fabricated, and characterized. A considerable wideband of 15.6 Hz at simulation and 13 Hz at experiment has been gained in a very low frequency range (below 50 Hz), with the acceleration of 1g. Experimental results show that the adjusted harvester could generate the output power of about 2.1 mW at an 8 Hz resonant frequency with the optimum load resistance 350

Effect of sintered temperature on structural and piezoelectric properties of barium titanate ceramic prepared by nano-scale precursors

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Unsymmetrical, interdigital vibration energy harvester: Bandwidth adjustment based on mode separation technique

. Meanwhile, the half-power (1.05 mW) bandwidth could reach up to 15.3 Hz. These results enable the designed device to improve viability for power supply of low power micro electron devices in some special low frequency vibration environment, such as large engineering applications, bridge monitoring, and wildlife monitoring.