With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rej...With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rejectioncontroller (ADRC) has been widely applied in various fields. However, in controlling plant protection unmannedaerial vehicles (UAVs), which are typically large and subject to significant disturbances, load disturbances andthe possibility of multiple actuator faults during pesticide spraying pose significant challenges. To address theseissues, this paper proposes a novel fault-tolerant control method that combines a radial basis function neuralnetwork (RBFNN) with a second-order ADRC and leverages a fractional gradient descent (FGD) algorithm.We integrate the plant protection UAV model’s uncertain parameters, load disturbance parameters, and actuatorfault parameters and utilize the RBFNN for system parameter identification. The resulting ADRC exhibits loaddisturbance suppression and fault tolerance capabilities, and our proposed active fault-tolerant control law hasLyapunov stability implications. Experimental results obtained using a multi-rotor fault-tolerant test platformdemonstrate that the proposed method outperforms other control strategies regarding load disturbance suppressionand fault-tolerant performance.展开更多
[Objectives]The paper was to study the effect of droplet drift on spray quality of plant protection UAV.[Methods]Based on the theory of multiphase flow and the method of particle kinematics,the force and motion trajec...[Objectives]The paper was to study the effect of droplet drift on spray quality of plant protection UAV.[Methods]Based on the theory of multiphase flow and the method of particle kinematics,the force and motion trajectory of droplet sprayed by plant protection UAV were theoretically analyzed and mathematically modeled.On the basis of the assumption of wind speed in the ground layer and the laminar sublayer,that is,it is assumed that the wind speed in the area of wind measurement was approximately a linear distribution,the coupling iterative solution of the equations was carried out.The influence of droplet diameter,flight height,flight speed of plant protection UAV,course angle,wind speed,wind direction,initial droplet velocity and direction of initial velocity on droplet drift were analyzed.The influence of the coupling effect of each factor on droplet drift was further discussed and the distribution of droplet drift concentration was obtained.[Results]The wind speed and direction had much influence on the drift distance of droplets,and the drift distance and the initial velocity angle show a quadratic function distribution.Under the given conditions,the drift distance was the closest when the initial velocity angle was about 20°.The droplet drift was mainly distributed scatteredly around the nozzle.[Conclusions]The study provides a reference for improving the spraying quality of plant protection UAV.展开更多
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. Visua...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.展开更多
Spray characteristics are the fundamental factors that affect droplet transportation downward,deposition,and drift.The downwash airflow field of the Unmanned Aviation Vehicle(UAV)primarily influences droplet depositio...Spray characteristics are the fundamental factors that affect droplet transportation downward,deposition,and drift.The downwash airflow field of the Unmanned Aviation Vehicle(UAV)primarily influences droplet deposition and drift by changing the spray characteristics.This study focused mainly on the effect of the downwash airflow field of the UAV and nozzle position on the droplet spatial distribution and velocity distribution,which are two factors of spray characteristics.To study the abovementioned characteristics,computational fluid dynamics based on the lattice Boltzmann method(LBM)was used to simulate the downwash airflow field of the DJI T30 six-rotor plant protection UAV at different rotor rotational speeds(1000-1800 r/min).A particle image velocimetry system(PIV)was utilized to record the spray field with the downwash airflow field at different rotational speeds of rotors(0-1800 r/min)or different nozzle positions(0,0.20 m,0.35 m,and 0.50 m from the motor).The simulation and experimental results showed that the rotor downwash airflow field exhibited the‘dispersion-shrinkage-redispersion’development rule.In the initial dispersion stage of rotor airflow,there were obvious high-vorticity and low-vorticity regions in the rotor downwash airflow field.Moreover,the low-vorticity region was primarily concentrated below the motor,and the high-vorticity region was mainly focused in the middle area of the rotors.Additionally,the Y-direction airflow velocity fluctuated at 0.4-1.2 m under the rotor.When the rotor airflow developed to 3.2 m below the rotor,the Y-direction airflow velocity showed a slight decrease.Above 3.2 m from the rotor,the Y-direction airflow velocity started to drastically decrease.Therefore,it is recommended that the DJI T30 plant protection UAV should not exceed 3.2 m in flight height during field spraying operations.The rotor downwash airflow field caused the nozzle atomization angle,droplet concentration,and spray field width to decrease while increasing the vortex scale in the spray field when the rotor system was activated.Moreover,the increase in rotor rotational speed promoted the abovementioned trend.When the nozzle was installed in various radial locations below the rotor,the droplet spatial distribution and velocity distribution were completely different.When the nozzle was installed directly below the motor,the droplet spatial distribution and velocity distribution were relatively symmetrical.When the nozzle was installed at 0.20 m and 0.35 m from the motor,the droplets clearly moved toward the right under the induction of stronger rotor vortices.This resulted in a higher droplet concentration in the right-half spray field.However,the droplet moved toward the left when the nozzle was installed in the rotor tip.For four nozzle positions,when the nozzle was installed at 0 or 0.20 m from the motor,the droplet average velocity was much higher.However,the droplet average velocity was slower when the nozzle was installed in the other two positions.Therefore,it is recommended that the nozzle is installed at 0 or 0.20 m from the motor.The research results could increase the understanding of the downwash airflow field distribution characteristics of the UAV and its influence on the droplet spatial distribution and velocity distribution characteristics.Meanwhile,the research results could provide some theoretical guidance for the choice of nozzle position below the rotor.展开更多
In order to study the regularity of the vertical distribution of droplet deposition on rice plants during pesticide spraying operated by a low-flying multi-rotor plant protection unmanned aviation vehicle(UAV),water-s...In order to study the regularity of the vertical distribution of droplet deposition on rice plants during pesticide spraying operated by a low-flying multi-rotor plant protection unmanned aviation vehicle(UAV),water-sensitive spray cards were placed on the leaves at the top,in the middle,and at the bottom of rice plants to acquire data on droplet deposition.In this study,a suspension containing tricylazole and hexaconazole was used in the spraying.The water-sensitive spray cards were analyzed by the droplet deposition processing software iDAS to obtain the vertical distribution of the droplets sprayed by the plant protection UAV.The results showed that (1)significant variation was found in the coverage of the droplets in different vertical positions of the rice plants.Within the effective spray width,the best coverage of the droplets was found in the area just below the rotors,whereas the coverage of areas farther away from the rotors was poor.For the different vertical positions of the rice plants,the overall droplet coverage was 58.38%at the top,33.55%in the middle,and 11.34%at the bottom of the plants;(2)for all vertical positions,the average size of the droplets ranged between 110μm and 140μm,which was suitable for the control of plant diseases and insect pests.The highest droplet density was found at the top of the plants,and the distribution of the droplet density was similar in the middle and at the bottom of the rice plants;(3)the diffusion ratio at the top of the rice plants(0.84)was better than that in the middle(0.57)and at the bottom(0.37).The overall relative span could meet the requirements for the actual application.Except for the position in the middle of the plants,the relative span for the other positions of the plants was over 0.67,which is the standard value.This study demonstrated the distribution regularity of droplet deposition along with the vertical direction of rice plants during UAV-based spraying,which is of guiding significance for the use of UAVs in plant protection,the improvement of chemical utilization efficiency,and the reduction of pesticide and fertilizer pollution.展开更多
Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This...Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This study presents a comprehensive overview of current bird repellant approaches used in agricultural contexts,as well as potential new ways. The bird repellent techniques include Internet of Things technology,Deep Learning,Convolutional Neural Network,Unmanned Aerial Vehicles,Wireless Sensor Networks and Laser biotechnology. This study’s goal is to find and review about previous approach towards repellent of birds in the crop fields using various technologies.展开更多
In order to solve the problems of insufficient training equipment,relatively lack of curriculum resources and single teaching means in the teaching of UAV(unmanned aerial vehicle)applied technology major,this paper st...In order to solve the problems of insufficient training equipment,relatively lack of curriculum resources and single teaching means in the teaching of UAV(unmanned aerial vehicle)applied technology major,this paper studies the application of MR(Mixed Reality)in UAV applied technology major teaching,with the teaching of UAV agriculture&forestry plant protection curriculum as the carrier.The study will solve the pain points in teaching,improve the teaching ability and teaching information level,and increase the talent training quality of UAV,agriculture&forestry plant protection and related majors.Furthermore,it will create a protective,interactive,remote and scalable teaching experience for stu-dents,which can improve the teaching effect and reduce the teaching cost.展开更多
Taihang Mountains are situated between Shanxi Province and the North China Plain,spanning Beijing,Hebei,Shanxi,and Henan provinces and cities.The mountains extend from northeast to southwest for over 400 km,naturally ...Taihang Mountains are situated between Shanxi Province and the North China Plain,spanning Beijing,Hebei,Shanxi,and Henan provinces and cities.The mountains extend from northeast to southwest for over 400 km,naturally deviding the second step from the third one in China.The southeastern area of Taihang Mountains specifically refers to Changzhi City and Jincheng Administrative Region of Shanxi Province.Given Shanxi Province’s robust development plans for the southeast area of Taihang Mountains,the medicinal plant resources in this area will be affected.Therefore,it is imperative and urgent to conduct a comprehensive investigation and study on the medicinal plant resources in the southeast area of Taihang Mountains.By means of field investigation,literature review,and specimen identification,the plant resources and diversity of two counties in the southeast of Taihang Mountains were evaluated.The findings revealed 234 plants species across 172 genera in 70 families,primarily comprising angiosperms.The families with more species included Compositae,Leguminosae,Rosaceae,Labiatae,Ranunculaceae.Among the genera,those with more species were Cynanchum,Selaginella,Clematis,Thalictrum,and Rhamnus.A total of 114 medicinal plants were identified,constituting 48.72%of the total.Regarding medicinal parts,the concentration is in roots and rhizomes,followed by whole plants and fruits.On the basis of investigation and study,some suggestions on the development,utilization,and protection of medicinal plant resources in southeast Taihang Mountains were made.These suggestions provide valuable insights for the study on medicinal plant resources and vegetation in the southeast of Taihang Mountains,serving as a scientific basis for the protection and sustainable utilization of wild medicinal plant resources.展开更多
Balluk Mountain is located between the Tianshan Mountains and the Altai Mountains in Xinjiang Province.Influenced by the humid air and diverse landforms of Lake Alacuri,the unique climate of Mount Baluk nourishes exce...Balluk Mountain is located between the Tianshan Mountains and the Altai Mountains in Xinjiang Province.Influenced by the humid air and diverse landforms of Lake Alacuri,the unique climate of Mount Baluk nourishes excellent pastures and supports numerous wildlife,making it rich in plant resources.The 9th Shenyang Pharmaceutical University Chinese Medicine Resources Scientific Expedition Team conducted field investigations,literature reviews,and specimen identification to study the plant resources and diversity of Balluk Mountain in Xinjiang Province.A total of 235 species of medicinal plants belonging to 59 families and 159 genera were collected during the period from July to August 2015 in this area.The dominant families observed were Asteraceae,Caryophyllaceae,Lamiaceae,Ranunculaceae,Rosaceae and Umbelliferae,with 35,11,14,12,27,and 13 species respectively.These families account for over 47.4%of the total species collected,though comprising only 10.2%of the total number of families.At the genus level,Artemisia was found to be the most dominant genus with eight species,contributing to 0.63%of the total genera,while representing 3.4%of the total species abundance.Overall,this study provides an updated analysis of the plant resources and diversity in Balluk Mountain.Several species have been identified to possess significant medicinal properties and hold potential for various research fields,including natural product chemistry and drug development.The study also offers practical and meaningful suggestions for strengthening the protection and utilization of plant resources in the area.By implementing these suggestions,we can better preserve the plant diversity in Balluk Mountain and ensure the sustainable use of these valuable resources.展开更多
Wuyi Mountain,located in the north of Fujian Province,China,is renowned for its abundant medicinal plant resources.In July 2014,the 8th(second team)of Shenyang Pharmaceutical University’s Chinese Medicine Resources S...Wuyi Mountain,located in the north of Fujian Province,China,is renowned for its abundant medicinal plant resources.In July 2014,the 8th(second team)of Shenyang Pharmaceutical University’s Chinese Medicine Resources Scientific Expedition Team conducted field investigation in the area.Through specimen collection and extensive literature review,the team identified and analyzed 223 vascular plant species from 175 genera and 85 families.The most dominant families were Compositae and Rosaceae,and perennial herbs were the predominant species,accounting for 44.39%of the total species identified.Notably,we documented five precious and rare medicinal plants unique to Wuyi Mountain.This study updates the database of plant resources and diversity in the region,providing a valuable reference for future studies.Finally,we put forward some suggestions to enhance the conservation and sustainable utilization of Wuyi Mountain’s plant resources.展开更多
DUS testing technique used for plant variety protection was reviewed in the paper, and somesuggestions were made on how to establish the appropriate technology system in China. Meanwhile, the poten-tial exploitation o...DUS testing technique used for plant variety protection was reviewed in the paper, and somesuggestions were made on how to establish the appropriate technology system in China. Meanwhile, the poten-tial exploitation of the technique was discussed.展开更多
In-situ study on eleven commercially important species viz; Adiantum capillus-veneris L, Bergenia ciliata (Haw) Sternb, Colchicum luteum Baker, Polygonum amplexicaule D.Den, Cuminum cyminum L, Dioscorea deltoidea Wall...In-situ study on eleven commercially important species viz; Adiantum capillus-veneris L, Bergenia ciliata (Haw) Sternb, Colchicum luteum Baker, Polygonum amplexicaule D.Den, Cuminum cyminum L, Dioscorea deltoidea Wall Kunth,L Morchella esculenta L, Paeonia emodi Wall ex H Kf, Podophyllum hexandrum (Royle) Chatt & Mukh, Valeriana wallichii DC and Viola serpens Wall ex Roxb was conducted in four locations viz; Malam (1 400 to 2 000?m),Bargin (1 700 to 2 300?m),Biakand (1 500 to 2 100?m) and Shinko (2 100 to 2 700?m).The data was recorded from both protected and unprotected sites of each site.Each site had 3 altitudinal sampling point.The density, herbage coverage and fresh biomass were determined in each locations for every species.All the investigated parameters generally showed an increase of 3 to 6 times over unprotected sites in each locations. Morchella esculenta,Dioscorea deltoidea,Colchicum luteum and Podophyllum hexandrum were absent in all unprotected sites while other species had low values in these sites.The investigated parameters of Colchicum luteum,Bergenia ciliata,Paeonioa emodi,Dioscorea deltoidea and Podophyllum hexandrum generally increased with the increasing elevation.Soil analysis,soil and air temperatures were recorded for each site.The air and soil temperature were slightly higher in open areas than in the protected site and showed decrease with increasing elevation.While the soil fertility was relatively high in protected sites as compared to unprotected area.The study shows that protection promotes the growth, distribution and occurrence of medicinal plants.It is possible with the participation of local communities to conserve these resources.展开更多
[Objective] The aim was to study the current situation and protection countermeasures of wild plant resources in Xishuangbanna National Nature Reserve. [Method] The current situation of wild plant resources in Xishuan...[Objective] The aim was to study the current situation and protection countermeasures of wild plant resources in Xishuangbanna National Nature Reserve. [Method] The current situation of wild plant resources in Xishuangbanna National Nature Reserve was researched by means of route survey, sample plot survey and literature survey, and then the main impact factors of wild plant resources were analyzed by using participatory rural appraisal and problem tree analysis, finally protection countermeasures were put forward according to current situation and main impact factors. [Result] There were 2 779 species of vascular plants belonging to 214 families and 1 012 genera (including subfamilies and varieties) in Xishuangbanna National Nature Reserve, among them, there existed 261 species of pteridophyte belonging to 41 families and 91 genera, 14 species of gymnosperm belonging to 6 families and 6 genera, and 2 504 species of angiosperm belonging to 167 families and 915 genera. Wild plant resources in reserve were mainly affected by planting under forest, habitat fragmentation, cutting trees, collection and utilization of no-timber products, development of animal husbandry, insufficient recognition of community residents to reserve management establishment and lots of floating population. In the future, wild plant resources in reserve could be protected through strengthening propaganda, education and management, enforcing the law strictly and other countermeasures. [Conclusion] The study could provide theoretical foundation for the protection of wild plant resources in Xishuangbanna National Nature Reserve.展开更多
Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early stream...Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early streamer emission lightning rod,lifting lightning rod and mobile lightning rod. Additionally,lightning protection methods and measures of landfill with large receiving area of lightning strike and landfill gas and incineration plant with irregular landfill cell are explored.展开更多
Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway(Tongjiang to Sanya) in Heilongjiang Province,China.The root lengths w...Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway(Tongjiang to Sanya) in Heilongjiang Province,China.The root lengths were divided into five root orders according to Pregizter sequence classification method.Results show that sea buckthorn roots are dominated by coarse roots in the horizontal growth,while L.bicolor has a large proportion of fine roots in vertical conical growth and A.fruticosa is in depth growth.Root length density of L.bicolor in all the root sequences is higher than that of sea buckthorn and A.fruticosa.On the basis of the root structure,it is inferred that L.bicolor roots mainly absorb the surface soil moisture for its normal growth;in contrast,A.fruticosa has good uptake ability to deep soil water.The root structure of sea buckthorn implies that it has a strong drought resistance.展开更多
DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails,it will seriously affect the normal production of nuclear power plant,causing great losses. So it ...DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails,it will seriously affect the normal production of nuclear power plant,causing great losses. So it is very important to take perfect lightning protection measures on DCS of the nuclear power plant. In this paper,according to the actual situation of DCS in a nuclear power plant,by controlling lightning point,securely booting lightning into the ground network,improving low-resistance ground network,eliminating ground loops,determining the safety space,surge protection of power and signal,a set of complete lightning protection design scheme was systematically put forward. Some specific lightning protection measures were highlighted,such as the DCS grounding,equipotential bonds and shields,and some specific considerations were put forward. All of these could offer reference in the practical application.展开更多
China is one of the countries in the world that is severely damaged by crop diseases,pests,and weeds.There are more than 1 700 species of agricultural pests occurring annually,53 of which are on the list of the 100 wo...China is one of the countries in the world that is severely damaged by crop diseases,pests,and weeds.There are more than 1 700 species of agricultural pests occurring annually,53 of which are on the list of the 100 worst pests in the world(Chen and Wang 2014;Wu 2018).Currently,China is still greatly challenged by a growing problem of agricultural pests that th reate n the economy and health and pose ecological risks underthe conditions of global climate change,economic integration,crop structure adjustment and so on.Plant protect!on agai nst crop diseases,in sect pests and noxious weeds is necessary to ensure high-quality crop production and food safety.However,traditional strategies of plant protect!on have mainly involved chemical pesticides.展开更多
Deicing agent is always applied to alleviate urban traffic pressure after snowing in winter,however,such a snow melting agent is extremely harmful for landscape plants.To eliminate or avoid such damages,we have been a...Deicing agent is always applied to alleviate urban traffic pressure after snowing in winter,however,such a snow melting agent is extremely harmful for landscape plants.To eliminate or avoid such damages,we have been actively exploring protection and treatment means.By analyzing the protection of landscape plants before using the deicing agent and the treatment after being damaged by the salt,the paper described how landscaping industry of Beijing handled extreme weather and influence of certain urban environment on landscape plants in a high-efficiency and low-cost way,and then figured out the balance point of normal social life and healthy development of ecological environment.展开更多
This paper studies farmers'privilege under the protection of new plant varieties,and points out that farmers'privilege is given to balance interests of plant breeders and relevant public.Based on this,it analy...This paper studies farmers'privilege under the protection of new plant varieties,and points out that farmers'privilege is given to balance interests of plant breeders and relevant public.Based on this,it analyzes shortcomings of farmers'privilege regulations,and puts forward that it is required to improve farmers'privilege regulations in subjects,objects and contents of rights on the basis of learning from advanced legislation experience of foreign countries,and build the interest sharing mechanism between breeders and farmers.展开更多
基金the 2021 Key Project of Natural Science and Technology of Yangzhou Polytechnic Institute,Active Disturbance Rejection and Fault-Tolerant Control of Multi-Rotor Plant ProtectionUAV Based on QBall-X4(Grant Number 2021xjzk002).
文摘With the increasing prevalence of high-order systems in engineering applications, these systems often exhibitsignificant disturbances and can be challenging to model accurately. As a result, the active disturbance rejectioncontroller (ADRC) has been widely applied in various fields. However, in controlling plant protection unmannedaerial vehicles (UAVs), which are typically large and subject to significant disturbances, load disturbances andthe possibility of multiple actuator faults during pesticide spraying pose significant challenges. To address theseissues, this paper proposes a novel fault-tolerant control method that combines a radial basis function neuralnetwork (RBFNN) with a second-order ADRC and leverages a fractional gradient descent (FGD) algorithm.We integrate the plant protection UAV model’s uncertain parameters, load disturbance parameters, and actuatorfault parameters and utilize the RBFNN for system parameter identification. The resulting ADRC exhibits loaddisturbance suppression and fault tolerance capabilities, and our proposed active fault-tolerant control law hasLyapunov stability implications. Experimental results obtained using a multi-rotor fault-tolerant test platformdemonstrate that the proposed method outperforms other control strategies regarding load disturbance suppressionand fault-tolerant performance.
基金Natural Science Foundation of Liaoning Province(20170540711).
文摘[Objectives]The paper was to study the effect of droplet drift on spray quality of plant protection UAV.[Methods]Based on the theory of multiphase flow and the method of particle kinematics,the force and motion trajectory of droplet sprayed by plant protection UAV were theoretically analyzed and mathematically modeled.On the basis of the assumption of wind speed in the ground layer and the laminar sublayer,that is,it is assumed that the wind speed in the area of wind measurement was approximately a linear distribution,the coupling iterative solution of the equations was carried out.The influence of droplet diameter,flight height,flight speed of plant protection UAV,course angle,wind speed,wind direction,initial droplet velocity and direction of initial velocity on droplet drift were analyzed.The influence of the coupling effect of each factor on droplet drift was further discussed and the distribution of droplet drift concentration was obtained.[Results]The wind speed and direction had much influence on the drift distance of droplets,and the drift distance and the initial velocity angle show a quadratic function distribution.Under the given conditions,the drift distance was the closest when the initial velocity angle was about 20°.The droplet drift was mainly distributed scatteredly around the nozzle.[Conclusions]The study provides a reference for improving the spraying quality of plant protection UAV.
基金Supported by Natural Science Foundation of Uygur Autonomous Region in 2020(2020D01C003)。
文摘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.
基金financially supported by the 111 Project(Grant No.D18019)Laboratory of Lingnan Modern Agriculture Project(Grant No.NT2021009)+4 种基金the Leading Talents of Guangdong Province Program(Grant No.2016LJ06G689)the National Natural Science Foundation of China(Grant No.32271985)the Natural Science Foundation of Guangdong Province(Grant No.2022A 1515011008No.2022A1515011535)Liaoning Provincial Education Department Key Research Project(Grant No.LSNZD 202005).
文摘Spray characteristics are the fundamental factors that affect droplet transportation downward,deposition,and drift.The downwash airflow field of the Unmanned Aviation Vehicle(UAV)primarily influences droplet deposition and drift by changing the spray characteristics.This study focused mainly on the effect of the downwash airflow field of the UAV and nozzle position on the droplet spatial distribution and velocity distribution,which are two factors of spray characteristics.To study the abovementioned characteristics,computational fluid dynamics based on the lattice Boltzmann method(LBM)was used to simulate the downwash airflow field of the DJI T30 six-rotor plant protection UAV at different rotor rotational speeds(1000-1800 r/min).A particle image velocimetry system(PIV)was utilized to record the spray field with the downwash airflow field at different rotational speeds of rotors(0-1800 r/min)or different nozzle positions(0,0.20 m,0.35 m,and 0.50 m from the motor).The simulation and experimental results showed that the rotor downwash airflow field exhibited the‘dispersion-shrinkage-redispersion’development rule.In the initial dispersion stage of rotor airflow,there were obvious high-vorticity and low-vorticity regions in the rotor downwash airflow field.Moreover,the low-vorticity region was primarily concentrated below the motor,and the high-vorticity region was mainly focused in the middle area of the rotors.Additionally,the Y-direction airflow velocity fluctuated at 0.4-1.2 m under the rotor.When the rotor airflow developed to 3.2 m below the rotor,the Y-direction airflow velocity showed a slight decrease.Above 3.2 m from the rotor,the Y-direction airflow velocity started to drastically decrease.Therefore,it is recommended that the DJI T30 plant protection UAV should not exceed 3.2 m in flight height during field spraying operations.The rotor downwash airflow field caused the nozzle atomization angle,droplet concentration,and spray field width to decrease while increasing the vortex scale in the spray field when the rotor system was activated.Moreover,the increase in rotor rotational speed promoted the abovementioned trend.When the nozzle was installed in various radial locations below the rotor,the droplet spatial distribution and velocity distribution were completely different.When the nozzle was installed directly below the motor,the droplet spatial distribution and velocity distribution were relatively symmetrical.When the nozzle was installed at 0.20 m and 0.35 m from the motor,the droplets clearly moved toward the right under the induction of stronger rotor vortices.This resulted in a higher droplet concentration in the right-half spray field.However,the droplet moved toward the left when the nozzle was installed in the rotor tip.For four nozzle positions,when the nozzle was installed at 0 or 0.20 m from the motor,the droplet average velocity was much higher.However,the droplet average velocity was slower when the nozzle was installed in the other two positions.Therefore,it is recommended that the nozzle is installed at 0 or 0.20 m from the motor.The research results could increase the understanding of the downwash airflow field distribution characteristics of the UAV and its influence on the droplet spatial distribution and velocity distribution characteristics.Meanwhile,the research results could provide some theoretical guidance for the choice of nozzle position below the rotor.
基金supported by the Key R&D Program of Liaoning Province(2020JH2/10200038)the National Key R&D Program of China(2016YFD0200700).
文摘In order to study the regularity of the vertical distribution of droplet deposition on rice plants during pesticide spraying operated by a low-flying multi-rotor plant protection unmanned aviation vehicle(UAV),water-sensitive spray cards were placed on the leaves at the top,in the middle,and at the bottom of rice plants to acquire data on droplet deposition.In this study,a suspension containing tricylazole and hexaconazole was used in the spraying.The water-sensitive spray cards were analyzed by the droplet deposition processing software iDAS to obtain the vertical distribution of the droplets sprayed by the plant protection UAV.The results showed that (1)significant variation was found in the coverage of the droplets in different vertical positions of the rice plants.Within the effective spray width,the best coverage of the droplets was found in the area just below the rotors,whereas the coverage of areas farther away from the rotors was poor.For the different vertical positions of the rice plants,the overall droplet coverage was 58.38%at the top,33.55%in the middle,and 11.34%at the bottom of the plants;(2)for all vertical positions,the average size of the droplets ranged between 110μm and 140μm,which was suitable for the control of plant diseases and insect pests.The highest droplet density was found at the top of the plants,and the distribution of the droplet density was similar in the middle and at the bottom of the rice plants;(3)the diffusion ratio at the top of the rice plants(0.84)was better than that in the middle(0.57)and at the bottom(0.37).The overall relative span could meet the requirements for the actual application.Except for the position in the middle of the plants,the relative span for the other positions of the plants was over 0.67,which is the standard value.This study demonstrated the distribution regularity of droplet deposition along with the vertical direction of rice plants during UAV-based spraying,which is of guiding significance for the use of UAVs in plant protection,the improvement of chemical utilization efficiency,and the reduction of pesticide and fertilizer pollution.
文摘Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This study presents a comprehensive overview of current bird repellant approaches used in agricultural contexts,as well as potential new ways. The bird repellent techniques include Internet of Things technology,Deep Learning,Convolutional Neural Network,Unmanned Aerial Vehicles,Wireless Sensor Networks and Laser biotechnology. This study’s goal is to find and review about previous approach towards repellent of birds in the crop fields using various technologies.
基金Supported by Vocational Education Reform and Innovation Project of Ministry of Education(HBKC217166,HBKC217168)Teaching Reform Project of Agricultural Specialty Teaching Steering Committee of Higher Vocational Education in Guangdong Province(YNYJZW2019YB09)+1 种基金Special Higher Vocational Enrollment Expansion Project of Teaching Reform Research and Practice Pro-ject in Guangdong Province(JGGZKZ2020141)Special Fund for Rural Revitalization Strategy of Huizhou in 2021(2021SC010502002)
文摘In order to solve the problems of insufficient training equipment,relatively lack of curriculum resources and single teaching means in the teaching of UAV(unmanned aerial vehicle)applied technology major,this paper studies the application of MR(Mixed Reality)in UAV applied technology major teaching,with the teaching of UAV agriculture&forestry plant protection curriculum as the carrier.The study will solve the pain points in teaching,improve the teaching ability and teaching information level,and increase the talent training quality of UAV,agriculture&forestry plant protection and related majors.Furthermore,it will create a protective,interactive,remote and scalable teaching experience for stu-dents,which can improve the teaching effect and reduce the teaching cost.
文摘Taihang Mountains are situated between Shanxi Province and the North China Plain,spanning Beijing,Hebei,Shanxi,and Henan provinces and cities.The mountains extend from northeast to southwest for over 400 km,naturally deviding the second step from the third one in China.The southeastern area of Taihang Mountains specifically refers to Changzhi City and Jincheng Administrative Region of Shanxi Province.Given Shanxi Province’s robust development plans for the southeast area of Taihang Mountains,the medicinal plant resources in this area will be affected.Therefore,it is imperative and urgent to conduct a comprehensive investigation and study on the medicinal plant resources in the southeast area of Taihang Mountains.By means of field investigation,literature review,and specimen identification,the plant resources and diversity of two counties in the southeast of Taihang Mountains were evaluated.The findings revealed 234 plants species across 172 genera in 70 families,primarily comprising angiosperms.The families with more species included Compositae,Leguminosae,Rosaceae,Labiatae,Ranunculaceae.Among the genera,those with more species were Cynanchum,Selaginella,Clematis,Thalictrum,and Rhamnus.A total of 114 medicinal plants were identified,constituting 48.72%of the total.Regarding medicinal parts,the concentration is in roots and rhizomes,followed by whole plants and fruits.On the basis of investigation and study,some suggestions on the development,utilization,and protection of medicinal plant resources in southeast Taihang Mountains were made.These suggestions provide valuable insights for the study on medicinal plant resources and vegetation in the southeast of Taihang Mountains,serving as a scientific basis for the protection and sustainable utilization of wild medicinal plant resources.
文摘Balluk Mountain is located between the Tianshan Mountains and the Altai Mountains in Xinjiang Province.Influenced by the humid air and diverse landforms of Lake Alacuri,the unique climate of Mount Baluk nourishes excellent pastures and supports numerous wildlife,making it rich in plant resources.The 9th Shenyang Pharmaceutical University Chinese Medicine Resources Scientific Expedition Team conducted field investigations,literature reviews,and specimen identification to study the plant resources and diversity of Balluk Mountain in Xinjiang Province.A total of 235 species of medicinal plants belonging to 59 families and 159 genera were collected during the period from July to August 2015 in this area.The dominant families observed were Asteraceae,Caryophyllaceae,Lamiaceae,Ranunculaceae,Rosaceae and Umbelliferae,with 35,11,14,12,27,and 13 species respectively.These families account for over 47.4%of the total species collected,though comprising only 10.2%of the total number of families.At the genus level,Artemisia was found to be the most dominant genus with eight species,contributing to 0.63%of the total genera,while representing 3.4%of the total species abundance.Overall,this study provides an updated analysis of the plant resources and diversity in Balluk Mountain.Several species have been identified to possess significant medicinal properties and hold potential for various research fields,including natural product chemistry and drug development.The study also offers practical and meaningful suggestions for strengthening the protection and utilization of plant resources in the area.By implementing these suggestions,we can better preserve the plant diversity in Balluk Mountain and ensure the sustainable use of these valuable resources.
文摘Wuyi Mountain,located in the north of Fujian Province,China,is renowned for its abundant medicinal plant resources.In July 2014,the 8th(second team)of Shenyang Pharmaceutical University’s Chinese Medicine Resources Scientific Expedition Team conducted field investigation in the area.Through specimen collection and extensive literature review,the team identified and analyzed 223 vascular plant species from 175 genera and 85 families.The most dominant families were Compositae and Rosaceae,and perennial herbs were the predominant species,accounting for 44.39%of the total species identified.Notably,we documented five precious and rare medicinal plants unique to Wuyi Mountain.This study updates the database of plant resources and diversity in the region,providing a valuable reference for future studies.Finally,we put forward some suggestions to enhance the conservation and sustainable utilization of Wuyi Mountain’s plant resources.
文摘DUS testing technique used for plant variety protection was reviewed in the paper, and somesuggestions were made on how to establish the appropriate technology system in China. Meanwhile, the poten-tial exploitation of the technique was discussed.
文摘In-situ study on eleven commercially important species viz; Adiantum capillus-veneris L, Bergenia ciliata (Haw) Sternb, Colchicum luteum Baker, Polygonum amplexicaule D.Den, Cuminum cyminum L, Dioscorea deltoidea Wall Kunth,L Morchella esculenta L, Paeonia emodi Wall ex H Kf, Podophyllum hexandrum (Royle) Chatt & Mukh, Valeriana wallichii DC and Viola serpens Wall ex Roxb was conducted in four locations viz; Malam (1 400 to 2 000?m),Bargin (1 700 to 2 300?m),Biakand (1 500 to 2 100?m) and Shinko (2 100 to 2 700?m).The data was recorded from both protected and unprotected sites of each site.Each site had 3 altitudinal sampling point.The density, herbage coverage and fresh biomass were determined in each locations for every species.All the investigated parameters generally showed an increase of 3 to 6 times over unprotected sites in each locations. Morchella esculenta,Dioscorea deltoidea,Colchicum luteum and Podophyllum hexandrum were absent in all unprotected sites while other species had low values in these sites.The investigated parameters of Colchicum luteum,Bergenia ciliata,Paeonioa emodi,Dioscorea deltoidea and Podophyllum hexandrum generally increased with the increasing elevation.Soil analysis,soil and air temperatures were recorded for each site.The air and soil temperature were slightly higher in open areas than in the protected site and showed decrease with increasing elevation.While the soil fertility was relatively high in protected sites as compared to unprotected area.The study shows that protection promotes the growth, distribution and occurrence of medicinal plants.It is possible with the participation of local communities to conserve these resources.
文摘[Objective] The aim was to study the current situation and protection countermeasures of wild plant resources in Xishuangbanna National Nature Reserve. [Method] The current situation of wild plant resources in Xishuangbanna National Nature Reserve was researched by means of route survey, sample plot survey and literature survey, and then the main impact factors of wild plant resources were analyzed by using participatory rural appraisal and problem tree analysis, finally protection countermeasures were put forward according to current situation and main impact factors. [Result] There were 2 779 species of vascular plants belonging to 214 families and 1 012 genera (including subfamilies and varieties) in Xishuangbanna National Nature Reserve, among them, there existed 261 species of pteridophyte belonging to 41 families and 91 genera, 14 species of gymnosperm belonging to 6 families and 6 genera, and 2 504 species of angiosperm belonging to 167 families and 915 genera. Wild plant resources in reserve were mainly affected by planting under forest, habitat fragmentation, cutting trees, collection and utilization of no-timber products, development of animal husbandry, insufficient recognition of community residents to reserve management establishment and lots of floating population. In the future, wild plant resources in reserve could be protected through strengthening propaganda, education and management, enforcing the law strictly and other countermeasures. [Conclusion] The study could provide theoretical foundation for the protection of wild plant resources in Xishuangbanna National Nature Reserve.
文摘Taking lightning-protection engineering of Wuhan Changshankou landfill and incineration plants for the example,in this article,we have discussed the integrated technology of direct lightning protection by early streamer emission lightning rod,lifting lightning rod and mobile lightning rod. Additionally,lightning protection methods and measures of landfill with large receiving area of lightning strike and landfill gas and incineration plant with irregular landfill cell are explored.
基金supported by Natural Science Fund Project of Heilongjiang Province (41309602)
文摘Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway(Tongjiang to Sanya) in Heilongjiang Province,China.The root lengths were divided into five root orders according to Pregizter sequence classification method.Results show that sea buckthorn roots are dominated by coarse roots in the horizontal growth,while L.bicolor has a large proportion of fine roots in vertical conical growth and A.fruticosa is in depth growth.Root length density of L.bicolor in all the root sequences is higher than that of sea buckthorn and A.fruticosa.On the basis of the root structure,it is inferred that L.bicolor roots mainly absorb the surface soil moisture for its normal growth;in contrast,A.fruticosa has good uptake ability to deep soil water.The root structure of sea buckthorn implies that it has a strong drought resistance.
基金Research Fund for Youth in Jiangsu Provincial Meteorological Bureau,China(Q201007)
文摘DCS (distributed control system) plays a decisive role in the overall operation of a nuclear power plant. If DCS fails,it will seriously affect the normal production of nuclear power plant,causing great losses. So it is very important to take perfect lightning protection measures on DCS of the nuclear power plant. In this paper,according to the actual situation of DCS in a nuclear power plant,by controlling lightning point,securely booting lightning into the ground network,improving low-resistance ground network,eliminating ground loops,determining the safety space,surge protection of power and signal,a set of complete lightning protection design scheme was systematically put forward. Some specific lightning protection measures were highlighted,such as the DCS grounding,equipotential bonds and shields,and some specific considerations were put forward. All of these could offer reference in the practical application.
文摘China is one of the countries in the world that is severely damaged by crop diseases,pests,and weeds.There are more than 1 700 species of agricultural pests occurring annually,53 of which are on the list of the 100 worst pests in the world(Chen and Wang 2014;Wu 2018).Currently,China is still greatly challenged by a growing problem of agricultural pests that th reate n the economy and health and pose ecological risks underthe conditions of global climate change,economic integration,crop structure adjustment and so on.Plant protect!on agai nst crop diseases,in sect pests and noxious weeds is necessary to ensure high-quality crop production and food safety.However,traditional strategies of plant protect!on have mainly involved chemical pesticides.
文摘Deicing agent is always applied to alleviate urban traffic pressure after snowing in winter,however,such a snow melting agent is extremely harmful for landscape plants.To eliminate or avoid such damages,we have been actively exploring protection and treatment means.By analyzing the protection of landscape plants before using the deicing agent and the treatment after being damaged by the salt,the paper described how landscaping industry of Beijing handled extreme weather and influence of certain urban environment on landscape plants in a high-efficiency and low-cost way,and then figured out the balance point of normal social life and healthy development of ecological environment.
文摘This paper studies farmers'privilege under the protection of new plant varieties,and points out that farmers'privilege is given to balance interests of plant breeders and relevant public.Based on this,it analyzes shortcomings of farmers'privilege regulations,and puts forward that it is required to improve farmers'privilege regulations in subjects,objects and contents of rights on the basis of learning from advanced legislation experience of foreign countries,and build the interest sharing mechanism between breeders and farmers.
