Design and Research of Efficient Adaptive Spray Plant Protection UAV

When the plant protection UAV is spraying on plants, the operator usually performs visual inspection on the vertical distance between the UAV and the plant to adjust the spray height to complete the application. Visual inspection by human eyes is easy to cause the error of spray deposition and deposition density. In order to improve the full utilization of drugs and the spraying efficiency of plant protection UAV, an efficient adaptive spray plant protection UAV was designed, and the vertical distance from the UAV to the plant was collected by ultrasonic wave. Meantime, the plant density was detected in real time, and the flight attitude of plant protection UAV and application rate of spray nozzle were automatically adjusted. The experimental results showed that the designed highly efficient adaptive spray plant protection UAV had fast response speed, precise spray location and less drug loss.

Analysis and Study on Characteristics and Detection Methods of Cotton Diseases and Insect Pests

[Objectives]The paper was to find the diseases and insect pests in the process of cotton growth quickly,effectively and timely.[Methods]The growth process of cotton was dynamically monitored by UAV aerial photography,and the aerial data map was converted into geotif image with longitude and latitude and then inputted into the detection system for preprocessing,mainly for image feature extraction and classification.Through deep learning of MATLAB software and BP neural network algorithm,the feature similarity of the images in the established characteristic database of cotton diseases and insect pests was compared.[Results]Through comparative analysis of characteristics of a large number of diseases and insect pests,it was found that deep learning method had high discrimination accuracy and good reliability.[Conclusions]The dynamic detection system using deep learning can well find cotton diseases and insect pests,and achieve early detection and early treatment,so as to effectively improve the yield and quality of cotton.

Bifunctional Silicon Quantum Dots for Antibacterial Application and Highly Sensitive Detection of Tetracycline

Silicon quantum dots(SiQDs)with high water-soluble and favorable photostability were prepared by a one-step hydrothermal method.The average diameter of SiQDs was 2.02 nm characterized by transmission electron microscope.It was to be noted that the as-prepared SiQDs showed eff ective antibacterial activity,which was attributed to electrostatic interaction and the generation of reactive oxygen species.The minimum inhibitory concentration of SiQDs against Escherichia coli and Staphylococcus aureus was 0.45 mg/mL and 0.38 mg/mL,respectively.Besides,based on the static quenching eff ect-induced fluorescence quenching mechanism,the SiQDs exhibited high sensitivity and selectivity for detecting tetracyclines(TC).A good linear relationship was obtained between the fluorescence intensity of SiQDs and the concentration of tetracycline(TC)in the range of 0–0.08μmol/L(R^(2)=0.9993)with a detection limit of 0.0176μmol/L.Furthermore,the TC content in the honey samples was determined using the SiQDs.All the results suggest that the as-prepared SiQDs can be a potential fluorescent probe for application in antibacterial and analysis.

Recommendations for control and prevention of infections for pediatric orthopedics during the epidemic period of COVID-19

The outbreak of Coronavirus Disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)emerged and spread rapidly throughout the world.As of February 29,2020,79389 cases of COVID-19 have been reported,and the outbreak is linked to 2838 deaths.The population is generally susceptible to the disease,and differences in incubation periods after infection exist among individuals.These two aspects of COVID-19 pose significant challenges to pediatric orthopedic diagnosis and treatment.As a dedicated center for managing pediatric cases of SARS-CoV-2 in Shanghai,our hospital has mobilized all branches and departments to undertake joint actions for scientific prevention and control,precise countermeasure and comprehensive anti-epidemic efforts.Combined with our experience,we have consulted the relevant national regulations and the latest research advances and have formulated the prevention and control measures of SARS-CoV-2 infection,including outpatient,emergency,inpatient and surgical cares,for clinical practices of pediatric orthopedics according to the physicochemical properties of SARS-CoV-2.It may serve as practical references and recommendations for managing SARS-CoV-2 infection in other pediatric specialties and in other hospitals.