Bionic flapping-wing micro air vehicles (FWMAVs) are promising for a variety of applications because of their flexibility and high mobility. This study reviews the state-of-the-art FWMAVs of various research institutes driven by electrical motor, mechanical transmission structure and “artificial muscle” material and then elaborates on the aerodynamic mechanism of micro-winged birds and insects. Owing to their low mass budget, FWMAVs require actuators with high power density from micrometer to centimeter scales. The selection and design of the mechanical transmission should be considered in parallel with the design of the power electronic interface required to drive it. Finally, power electronic topologies suitable for driving “artificial muscle” materials used in FWMAVs are stated.

Tunable diode laser absorption spectroscopy technology (TDLAS) has been widely applied in gaseous component analysis based on gas molecular absorption spectroscopy. When dealing with molecular absorption signals, the desired signal is usually interfered by various noises from electronic components and optical paths. This paper introduces TDLAS-specific signal processing issues and summarizes effective algorithms so solve these.

Spin-exchange relaxation-free (SERF) atomic magnetometers seem to be the state-of-the-art magnetic sensors today as they have achieved a sensitivity of femtotesla in the elimination of broadening contribution of spin-exchange collisions operated in the mode of SERF regime. In order to extend the practicability of SERF atomic magnetometry in superb performances in a movable platform, ensuring and testing the working status of alkali atoms are of great importance. Given the fact that in the premise of SERF regime, the linewidth of magnetic resonance would be narrowing down and the precession frequency would become a constant fractional value of the Larmor frequency for alkali atoms, we measure the gyromagnetic ratio of weakly polarized alkali-metal vapor by yielding the damped oscillating curves and fitting measured increments of frequency and magnetic field to identify the working regime of alkali atoms in a fast and straightforward manner. The experimental results have good agreements with theoretical analysis and simulation, and the whole measurement process lasts milliseconds with relatively measured error ± 1% in the temperature range of T = 156 °C-184 °C. To testify the validity of the innovation, magnetic resonance line is obtained in the same condition proffering the width comparative with the outcome from simulation, indicating the spin-exchange broadening has been eliminated, presenting the same conclusion with innovation, and providing systematic sensitivity 30 fT/Hz1/2.

For deep-sea natural gas hydrate exploration, highly sensitive detection of the dissolved gas in seawater near the seabed is significant because it requires the sensor system to be small in size, low in power consumption, and high in sensitivity. A mid-infrared sensor system was developed to detect dissolved carbon dioxide (CO₂) in sea-water, while employing a 4319 nm continuous-wave interband cascade laser (ICL) and a multi-pass gas cell (MPGC) with a 29.8 m optical path length. A compact rectilinear optical structure was proposed by using the free-space-emitting ICL and tunable laser absorption spectroscopy (TLAS). This leads to a minimized sensor size and a simple optical alignment for deep-sea operation. A strong CO₂ absorption line, located at 2315.19 cm⁻¹ and a weak 2315.28 cm⁻¹ line and at a low pressure of 40 Torr, was targeted for low- and high-concentration CO₂ detection within a concentration range of 0-1000 parts per billion by volume (ppbv) and 0-40 parts per million by volume (ppmv), respectively. The limit of detection (LoD) was assessed to be 0.72 ppbv at an averaging time of 2 s, and the response time was measured to be ~30 s at a flow rate of ~180 standard cubic centimeters per minute (sccm). Deployment of the CO₂ sensor combined with a gas-liquid separator was carried out for the CO₂ detection in the gas extracted from water, which validated the reported sensor system’s potential application for deep-sea natural gas hydrate exploration.

Cd/In-glycerate spheres are synthesized through a simple solvothermal method. After thermal treatment, these Cd/In-glycerates can be converted into CdIn₂O₄ spheres. Many characterization methods were performed to reveal the microstructure and morphology of the CdIn₂O₄. It was found that pure CdIn₂O₄ phase was obtained for the Cd/In starting materials at ratios of 1:1.6. The CdIn₂O₄ spheres are composed by a large number of nanoparticles subunits. The CdIn₂O₄ sphere-based sensor exhibited a low detection limit (1 ppm), high response (81.20 to 500 ppm n-butanol), fast response (4 s) and recovery (10 s) time, good selectivity, excellent repeatability, and stability at 280 °C. Our findings highlight the possibility to develop a novel gas sensor based on CdIn₂O₄ for application in n-butanol detection with high performance.

In this study, a micro converter for driving a piezoelectric actuator is designed and implemented. The converter can produce 100 V, 80 Hz AC voltage from 3.7 V DC voltage. With regard to the requirements of micro mobile robots, the main contributions of this study are the design and implementation of a circuit topology supplying power for micro mobile robots at low power and the miniaturization of this topology to make it suitable for driving a centimeter-level robot. The 91 mg mass (excluding printed circuit board mass), 14 × 12 × 4 mm size, and 84.6% efficiency of the converter indicate that this circuit could be applied in micro mobile robots driven by piezoelectric actuators.