Yanqing Zhang

Chitosan films have attracted increasing attention as biodegradable packaging materials; however, their relatively low stiffness and limited mechanical stability restrict their practical application. In this study, ramie elementary fiber-reinforced chitosan composite films were prepared using ramie elementary fiber suspensions at concentrations of 0, 0.5, 1.0, and 1.5 g/L. The mechanical properties, chemical interactions, crystalline structure, and surface morphology of the composite films were systematically investigated by tensile testing, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results showed that the incorporation of ramie elementary fibers significantly affected the mechanical behavior of chitosan films. Among the tested concentrations, the composite film with 0.5 g/L ramie elementary fibers exhibited the best overall performance, with the elastic modulus increasing by 130% from 67.46 MPa to 155.14 MPa compared with the pure chitosan film. FTIR analysis indicated that the formation of hydrogen-bonding between ramie elementary fibers and the chitosan matrix, while XRD results showed that the incorporation of ramie elementary fibers enhanced the structural ordering of the chitosan-based composite films without forming a new crystalline phase. SEM observations further confirmed that an appropriate fiber content promoted uniform dispersion and good interfacial bonding, whereas excessive fiber addition led to aggregation, surface roughening, and interfacial defects. These findings demonstrate that low-content ramie elementary fibers can effectively improve the stiffness and structural stability of chitosan composite films, providing a potential strategy for developing biodegradable fiber-reinforced packaging materials.

Accurate detection and segmentation of young ‘Yuluxiang’ pear fruits at the fruit thinning stage are crucial for the development of intelligent fruit thinning robots. To address the challenges in recognition and segmentation of young ‘Yuluxiang’ pears in natural environments characterized by occlusion, overlap, and small targets, this paper proposes an improved instance segmentation model based on YOLOv8n-seg, named YOLOv8n-DSW. Firstly, the C2f modules were optimized by introducing DualConv to construct C2f-Dual modules, which enhanced feature extraction capability while reducing the number of parameters. Secondly, a Spatial-Channel Synergistic Attention (SCSA) mechanism was embedded ahead of the small-object detection head to improve detection accuracy for small targets. Finally, the original CIoU loss function was replaced with the WIoU v3 loss function to accelerate model convergence and improve accuracy. Deployment on a Firefly ROC-RK3588S-PC development board confirmed the model’s suitability for edge devices. Experimental results demonstrated that YOLOv8n-DSW achieved excellent performance. The mAP₅₀, mAP₇₅, and mAP_50:95 for detection reached 95.6%, 83.2%, and 70.3%, respectively, and those for segmentation were 94.8%, 78.2%, and 65.3%. The proposed model outperformed its baseline, YOLOv8n-seg, as well as other classic models such as YOLOv5n-seg, YOLOv11n-seg, and YOLOv12n-seg. These results demonstrate that YOLOv8n-DSW provides accurate and efficient segmentation of young ‘Yuluxiang’ pear fruits.

A self-propelled multi-duct air-delivered sprayer was developed to address the challenges of dense canopies and low pesticide utilization in closed-canopy apple orchards. It featured an intelligently adjustable spray bar and formed a directional air curtain via a centrifugal fan and a duckbill air outlet to improve droplet penetration. Using CFD simulations, the air duct size and the air outlet distance were optimized, and the field orthogonal test was carried out with driving speed, nozzle pressure, and nozzle type as factors. The results showed that the optimal parameters were an air duct size of 230 × 110 mm, an air outlet distance of 350 mm, and a fan speed of 2160 r/min. Compared to liquid pump independent operation, liquid pump–fan cooperative operation significantly increased droplet deposition density (p < 0.05) and reduced the degree of dispersion. All three factors significantly influenced deposition density (p < 0.05), and nozzle type had the greatest influence on deposition density, followed by nozzle pressure, and then driving speed. Optimal performance was obtained at a 0.3 m/s driving speed, a 3 MPa nozzle pressure, and a 6502 nozzle type. Under the optimal combination of operating parameters, field verification tests demonstrated that cooperative operation achieved higher average coverage (60.54% vs. 48.30%) and average deposition density (71.34 vs. 60.54 droplets/cm²), with a more uniform coefficient of variation in droplet coverage on leaves (a range of 13.37–19.07% vs. 9.70–22.67%). These results indicate that the sprayer exhibits strong penetration and provides good uniform coverage, effectively increasing droplet deposition across different canopy heights.

To solve the problem of large sowing amount and poor sowing uniformity for millet, according to the physical characteristics of the millet seed and its sowing agronomic requirements, an electromagnetic vibration type fine and small-amount seeder was designed, and the main technical parameters of the seeder were determined, in order to realize the functions of furrow opening, electronically controlled seed metering, soil covering and pressing. Based on the principle of electromagnetic vibration, an electromagnetic vibration type seed metering device was designed to achieve uniform seeding of the millet seed with a small sowing amount; a seeding amount electronic control device was designed using an STM32 microcontroller, which realized the switching to sowing agronomic mode and the adjustment of the seeding amount with sowing operation speed; a vibration experimental bench was set up to simulate the vibration state of field operation, and studies on the seeding performance and vibration damping of the seed metering device by the isolation spring were carried out, as well as field sowing tests for verification. When the working voltage of the seed metering device is 80–160 V, the coefficients of variation for seeding uniformity per row and for total seeding uniformity are not greater than 3.57% and 2.39%, respectively, and the seed damage rate is less than 0.5%. The installation of isolation springs can increase the maximum vibration acceleration of the seed metering device by 10.61–28.20%, significantly reducing the impact of external vibrations on the seed metering device. Within the range of suitable sowing operation speeds, the electronic control device can meet the seeding amounts along with sowing operation speed in the 6, 7.5 and 9 kg/hm² sowing agronomic modes, and the coefficient of variation for seeding uniformity per row, for total seeding uniformity and for sowing uniformity are not greater than 4.63%, 2.48% and 23.38%, respectively. This study provides a reference for the development of sowing machinery for millet crop.

Mechanized harvesting is a crucial step in the agricultural production of foxtail millet (Setaria italica), as its peduncles are susceptible to bending and breaking during the harvesting process, leading to yield losses and deterioration in grain quality. To evaluate the suitability of foxtail millet for mechanical harvesting, this study comprehensively analyzed the biomechanical properties of the peduncles and related biological morphological characteristics of 116 foxtail millet accessions, establishing a system for indicator screening and comprehensive evaluation. Using partial correlation analysis and R-type cluster analysis, four biomechanical and seven related morphological indices of the peduncle were screened from 22 candidate indicators, with their coefficient of variation ranging from 6% to 80%. The entropy method was used to assign weights to the selected indices, with biomechanical factors contributing 47.4%, peduncle morphology 20.2%, spike morphology 27.6%, and plant height 4.8%. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Rank-Sum Ratio (RSR) methods were applied to rank and grade the classification of the 116 foxtail millet varieties into four performance groups: Excellent (8 varieties), Good (50 varieties), Moderate (51 varieties), and Poor (7 varieties). This study provides a scientific basis for the selection and evaluation of foxtail millet varieties.

To determine the patterns and influencing factors of the mechanical properties of millet stems from different varieties during the maturity period, this study employed a complete block experiment method and conducted shearing and bending tests on millet stems using the INSTRON5544 electronic universal material testing machine. The research investigated the variation in the shear strength, specific shear energy, bending strength, elastic modulus, and bending stiffness at different internode positions of the stems of Changza 466, Zhangza 16, and Jingu 21 during their maturity period. The results indicated that the variety had a significant impact on the mechanical properties of millet stems: from largest to smallest, the order of shear and bending forces was Jingu 21, Zhangza 16, and Changza 466. The shear strength and bending strength of Jingu 21 were the greatest among the three stem samples. The internode position significantly affected the shear mechanical properties of the millet stems, showing a general trend of decreasing shear strength with ascending internode position. The effect of the internode position on the bending stiffness was highly significant, whereas its impact on the bending strength and elastic modulus was not significant. The shear strength of the millet stems ranged from 3.866 ± 1.086 to 6.953 ± 2.208 MPa, significantly lower than the bending strength, which ranged from 18.934 ± 4.374 to 34.286 ± 6.875 MPa. The lowest shear strength and specific shearing energy, recorded at the fifth internode, were 4.028 ± 1.918 MPa and 15.097 ± 12.633 MJ/mm², respectively. Jingu 21 and Changza 466 exhibit better lodging resistance than Zhangza 16. It is recommended to use a cutting-type platform for harvesting millet stems, with the cutting height set at the fifth internode position. This study provides a theoretical basis for the design of millet harvesting machinery and the selection of harvest parameters.

Water is one of the important factors affecting pork quality. In this study, near-infrared (NIR) spatially resolved (SR) spectroscopy was used to detect the water content of pork. The SR spectra of 150 pork samples were collected within the light source–detector (LS-D) distance range of 4–20 mm (distance interval 1 mm). Models were established based on single-point SR spectra of 17 different LS-D distances and combination SR spectra. The results indicated that combination SR spectra achieved better model performance than the single-point SR spectra, and the LS-D distance significantly affected the model accuracy. The optimal LS-D distance combination of 5, 7, 10, and 12 mm provided the best detection model with the calibration determination coefficient (R²_C) of 0.915 and prediction determination coefficient (R²_P) of 0.878. Using the competitive adaptive reweighted sampling (CARS) algorithm, 24 characteristic wavelengths were selected. The model built with the characteristic wavelengths also exhibited good detection accuracy, with a R²_C of 0.909 and a R²_P of 0.867, and the number of wavelengths was greatly reduced compared to the full-wavelength model. This study demonstrated that SR spectroscopy combined with the optimized LS-D distances and screened characteristic wavelengths can be a powerful tool for detecting the water content of pork.

Edible coatings have attracted the attention of researchers in recent years due to their degradability, safety, non-toxicity, low cost, good preservation effect, and other advantages. To prepare a new edible film with good mechanical and barrier properties, carboxymethyl chitosan (CMCS) and gelatin (GL) were selected as the film-forming matrix in this experiment, and glycerol, CaCl₂, Tween-20, and ascorbic acid (AA) have been added as plasticizers, crosslinking agents, surfactants, and antioxidants. Crosslinking agents and antioxidants first, the film was prepared by the casting method, and single factor tests were used to compare the effects of different CMCS: GL (w:w), glycerol, CaCl₂, Tween-20, and AA on mechanical properties (Tensile Strength (TS), Elongation at break (EAB)) and barrier properties (Water Vapor Permeability (WVP), Oxygen Permeability (OP)). Then, the weighting of each performance index is determined by a combination of principal component analysis and the comprehensive membership evaluation method. The formula for calculating the overall rating of edible film performance was determined. Finally, the manufacturing process of edible film with better performance was optimized by a response surface test. The results showed that the influence of each factor on the performance of the edible film was as follows: Glycerol addition > CaCl₂ addition > CMCS:GL, Tween-20, and AA had no significant influence on the performance of the edible film. When calculating the overall edible film property score, the weights of TS, EAB, WVP, and OP were 0.251, 0.068, 0.334, and 0.347, respectively. The optimal formulation for an edible film based on CMCS-GL with better properties than pure CMCS and GL film was CMCS:GL = 2:1, with the addition of 1% glycerol, 2% CaCl₂, 0.1% Tween-20, and 2% AA. The TS, EAB, OP, and WVP of the film obtained with this formula were: 16.28 MPa, 71.46%, 1.39 × 10⁻¹² g·cm/(cm²·s·Pa), 5.10 × 10⁻¹¹ cm³·cm/(m²·s·Pa), respectively. This study suggests that CMCS-GL-based edible coatings can be used as a new food packaging material.

To prepare an edible coating with a good preservative effect on sweet cherries, carboxymethyl chitosan (CMCS) and gelatin (GL) were selected as the film-forming matrix in this experiment, and CaCl2 and ascorbic acid (AA) were added as crosslinking agents and antioxidants, respectively. First, the film was prepared by the casting method, and the film formula with better mechanical and barrier performance was filtered out by one-factor and response surface optimization test, and the differences in the preservation effect of different film formulations (CMCS-GL, CaCl2- CMCS-GL, AA -CaCl2- CMCS-GL) on sweet cherries were compared. and then the different film formulations were compared. The difference in film formulation on the preservation effect of sweet cherries was investigated. The results showed that the optimal formulation for an edible film based on CMCS-GL with good performance was CMCS: GL (w:w)=2:1, with the additional amount of 1% glycerol, 2% CaCl2, 0.1% Tween-20, 2% AA, the tensile strength, elongation at break, oxygen permeability and water vapor permeability of the film obtained with this formula were: 16.28 MPa, 71.46%, 1.39×10-12 g- cm/(cm2-s-Pa), 5.10×10-11 cm3-cm/(m2-s-Pa), respectively. In the preservation of sweet cherries, all three film formulations effectively reduced the rotting rate and weight loss during storage while preserving the high hardness and skin color of the fruit. Among them, the formulation AA -CaCl2- CMCS-GL showed the best preservation effect and can be used as a new method for postharvest preservation of sweet cherries.