This paper investigates a simple memristor emulator consisting of a diode bridge and a capacitor. It exhibits pinched hysteresis loops, and what is more striking is the higher frequency, as it operates up to greater than 5 MHz. Based on the proposed memristor, a higher-frequency Colpitts circuit was established. According to the mathematical model of the system, the system only possesses one unstable equilibrium point. Period doubling bifurcation, reverse periodic doubling bifurcation, different types of periodic and chaotic orbits, transient chaos, coexisting bifurcations and offset boosting are depicted. More interestingly, it has coexisting multiple attractors with different topologies, such as a chaotic attractor accompanied with periodic orbits, period-1 orbits with bicuspid structure and periodic-2 orbits with tridentate structure. Moreover, a hardware circuit using discrete components was fabricated and experimental measurements were consistent with the MATLAB numerical results, further confirming the real feasibility of the proposed circuit.

During the flowering period of mango trees, pests often hide in the inflorescences to suck sap, affecting fruit formation. By accurately detecting the number and location of mango inflorescences in the early stages, it can help target-specific spraying equipment to perform precise pesticide application. This study focuses on mango panicles and addresses challenges such as high crop planting density, poor image quality, and complex backgrounds. A series of improvements were made to the YOLOv8 model to enhance performance for this type of detection task. Firstly, a mango panicle dataset was constructed by selecting, augmenting, and correcting samples based on actual agricultural conditions. Second, the backbone network of YOLOv8 was replaced with FasterNet. Although this led to a slight decrease in accuracy, it significantly improved inference speed and reduced model parameters, demonstrating that FasterNet effectively reduced computational complexity while optimizing accuracy. Further, the GAM (Global Attention Module) attention mechanism was introduced as an attention module in the backbone network to enhance feature extraction capabilities. Experimental results indicated that the addition of GAM improved the average precision by 2.2 percentage points, outperforming other attention mechanisms such as SE, CA, and CBAM. Finally, the model’s bounding box localization ability was enhanced by replacing the loss function with WIoU, which also accelerated model convergence and improved the mAP@.5 metric by 1.1 percentage points. Our approach demonstrates a discrepancy of less than 10% compared to manual counted results.

A theoretical model of a gain-switched Fe:ZnSe laser pumped by a pulsed 2.8 μm fiber laser is established. The numerical simulation is carried out based on the finite difference method. The effects of parameters such as pump pulse waveform, pump pulse width, pump power, crystal temperature, and doping concentration on the pulse shape, pulse width, and peak power of the gain-switched laser pulses are simulated and studied. The generation and splitting evolution of a laser pulse under weak and strong pumping powers are analyzed, and the law of the influence of relevant parameters on the laser pulses is obtained. The numerical results show that the dynamic gain and loss in the laser resonator cavity affect the time required for the establishment of a dynamic balance of the photons, while the pump power, repetition rate, and coupling rate affect the time required for a stable laser pulses output. Under a same pumping pulse energy, the Gaussian pulse pumping generates laser pulse with a higher peak power and a narrower pulse width, and the generation of laser pulses is ealier. At a low temperature (77 K), the gain-switched Fe:ZnSe laser can generate laser pulses with high peak power and single peak waveform under appropriate doping concentration and pump power conditions. At low pumping power, there is an optimized concentration, not the greater the better. To obtain the same frequency of laser pulse output, it is necessary to consider the excited-state absorption and crystal length at high concentrations, comprehensively.