The existing 2D settlement monitoring systems for utility tunnels are heavily reliant on manual interpretation of deformation data and empirical predictionmodels.Consequently,early anomalies(e.g.,minor cracks)are ofte...The existing 2D settlement monitoring systems for utility tunnels are heavily reliant on manual interpretation of deformation data and empirical predictionmodels.Consequently,early anomalies(e.g.,minor cracks)are often misjudged,and warnings lag by about 24 h without automated spatial localization.This study establishes a technical framework for requirements analysis,architectural design,and data-integration protocols.Revit parametric modelling is used to build a 3D tunnel model with structural elements,pipelines and 18 monitoring points(for displacement and joint width).Custom Revit API code integrated real-time sensor data into the BIM platform via an automated pipeline.The system achieved a spatial accuracy of±1 mm in locating deformation hotspots.Notifications are triggered within 10 s of anomaly detection,and the system renders 3D risk propagation paths in real-time.Realtime 3D visualization of risk propagation paths is also facilitated.The efficacy of the solution was validated in a Ningbo utility tunnel project,where it was demonstrated that it eliminates human-dependent judgment errors and reduces warning latency by 99.9%compared to conventional methods.The BIM-IoT integrated approach,which enables millimetre-level precision in risk identification and near-instantaneous response,establishes a new paradigm for intelligent infrastructure safety management.展开更多
Al/NH_(4)CoF_(3)-Φ(Φ=0.5,1.0,1.5,2.0,and 3.0)binary composites and Al-NH_(4)CoF_(3)@P(VDF-HFP)ternary composites are fabricated via ultrasonication-assisted blending and electrostatic spraying.The effect of equivale...Al/NH_(4)CoF_(3)-Φ(Φ=0.5,1.0,1.5,2.0,and 3.0)binary composites and Al-NH_(4)CoF_(3)@P(VDF-HFP)ternary composites are fabricated via ultrasonication-assisted blending and electrostatic spraying.The effect of equivalence ratio(Φ)on the reaction properties is systematically investigated in the binary Al/NH_(4)CoF_(3)system.For ternary systems,electrostatic spraying allows both components to be efficiently encapsulated by P(VDF-HFP)and to achieve structural stabilization and enhanced reactivity through synergistic interfacial interactions.Morphological analysis using SEM/TEM revealed that P(VDF-HFP)formed a protective layer on Al and NH_(4)CoF_(3)particles,improving dispersion,hydrophobicity(water contact angle increased by 80.5%compared to physically mixed composites),and corrosion resistance.Thermal decomposition of NH_(4)CoF_(3)occurred at 265℃,releasing NH_(3)and HF,which triggered exothermic reactions with Al.The ternary composites exhibited a narrowed main reaction temperature range and concentrated heat release,attributed to improved interfacial contact and polymer decomposition.Combustion tests demonstrated that Al-NH_(4)CoF_(3)@P(VDF-HFP)achieved self-sustaining combustion.In addition,a simple validation was done by replacing the Al component in the aluminium-containing propellant,demonstrating its potential application in the propellant field.This work establishes a novel strategy for designing stable,high-energy composites with potential applications in advanced propulsion systems.展开更多
Composite water samples taken from Owena Multi-purpose Dam in six sampling campaigns covering the wet and dry seasons were analyzed for physico-chemical and microbial characteristics using standard methods for the exa...Composite water samples taken from Owena Multi-purpose Dam in six sampling campaigns covering the wet and dry seasons were analyzed for physico-chemical and microbial characteristics using standard methods for the examination of water and wastewater jointly published by the American Public Health Association, American Water Works Association and Water Pollution Control Federation. Results showed significant (p < 0.05) seasonal variations in most measured parameters with few showing significant spatial variation. The characteristics of the water from the dam lake revealed an acceptable quality for most measured parameters with low chemical pollutants burden when compared with drinking water standards and water quality for aquaculture. However, high values of turbidity, colour, iron, manganese and microbial load were recorded compared with drinking water standards, which call for proper treatment of the water before distribution for public consumption.展开更多
Designing of a multi-purpose plant as one of the well-known manufacturing systems is more challenging than other manufacturing systems. This paper applies a stochastic colored Petri net (CPN) to design and analyze mul...Designing of a multi-purpose plant as one of the well-known manufacturing systems is more challenging than other manufacturing systems. This paper applies a stochastic colored Petri net (CPN) to design and analyze multi-purpose plants. A simple approach is proposed to determine the utilization of shared resources and to reduce the equipment’s idle times. Three scenarios are presented to describe the proposed model. Generally, according to desire of a decision maker, different scenarios can be considered in the model to achieve to the expected design or plant configuration. The main characteristics of the proposed model are flexibility, the easiness of practical application and the simulation of the model in an easy way.展开更多
The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The...The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The radial and poloidal electric fields （Sr, Ep） and ion saturation current （Is） are measured by multi-purpose probe （MPP）. This probe is fabricated and constructed for the first time in the IR-T1 tokamak. The most advantage of this probe is that the variations of Er and Ep can be measured in different radii at the single shot. Thus the information of different radii can be compared with high precision. The bias voltage is fixed at Vbias = 200 V and it has been applied with the limiter bias that is fixed in r/a = 0.9. Moreover, the phase difference between radial and poloidal electric fields, and temporal evolution of the RS .spectrum detected by MPP are calculated. RS magnitude on the edge （r/a = 0.9） is more than its value in the SOL （r/a = 1.02）. With the applied bias 200 V, ItS and the magnitude of the phase difference between Er and Ep are increased, while the radial turbulent transport is decreased simultaneously. Thus it can be concluded that RS affects radial turbulence. Temporal evolution of the RS spectrum shows that the frequency of RS is increased and reaches its highest value at r/a=0.9 in the presence of bias.展开更多
Aimed at current deficiencies of multi-purpose guided missile kill probability model against gunship, the concept of the important coefficient of vulnerability blade unit is proposed in this paper. Laser fuze actuatio...Aimed at current deficiencies of multi-purpose guided missile kill probability model against gunship, the concept of the important coefficient of vulnerability blade unit is proposed in this paper. Laser fuze actuation model and warhead condition kill probability model of rotor blades are established by Monte Carlo method and kinetics theory with new ideas. Based on limited data, armor thickness of gunship is estimated, and a complete multi-purpose guided missile kill probability mathematical model is established, which provides necessary mathematical tool for the accurate and objective analysis of multi-purpose guided missile kill probability against gunship. Based on the establishment of the model, sensitivity analysis and optimal design of the main factors of multi-purpose guided missile kill probability are conducted, and the results show that the single multi-purpose guided missile lethality performance can be improved significantly by sensitivity analysis and optimization.展开更多
To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conduct...To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.展开更多
To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying ...To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method.The morphology,structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS),infrared spectroscopy(FT-IR),and simultaneous thermal analyzer(TG-DSC).Additionally,the combustion process of the samples was tested using a high-speed camera.The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size.The Si/NC/CL-20 composite explosive has better and more uniform sphericity,with an average particle size of 73.4 nm,compared to the NC/CL-20 composite explosive.The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method,achieves physically uniform distribution of the components including NC,CL-20,Si.The addition of Si promotes the thermal decomposition of CL-20.In comparison to the NC/CL-20 composite explosive,the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78 kJ/mol,and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12 K and 2.61 K,respectively.Furthermore,Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive,which shows that Si can improve the combustion performance of CL-20.展开更多
The spraying robot for building exterior walls is an innovative technology in the field of modern construction.This paper discusses its design structure,application cases,technical benefits,and industrial impacts.Rese...The spraying robot for building exterior walls is an innovative technology in the field of modern construction.This paper discusses its design structure,application cases,technical benefits,and industrial impacts.Research shows that this type of robot improves the efficiency and quality of exterior wall construction.Its intelligent design enhances operation accuracy and safety,reduces costs and risks,and strengthens application ability in complex environments,showing broad application prospects and symbolizing the development trend of intelligence and automation in the industry.In the future,it is necessary to strengthen its intelligence and adaptive ability further,explore multi-function design,promote automation technology,and ensure construction safety and economic benefits.展开更多
AlCoCrFeNi and AlCoCrFeNiSi high entropy alloy(HEA)coatings have been prepared by high velocity oxygen fuel spraying,and the microstructure,mechanical properties as well as wear behaviors of the two HEA coatings were ...AlCoCrFeNi and AlCoCrFeNiSi high entropy alloy(HEA)coatings have been prepared by high velocity oxygen fuel spraying,and the microstructure,mechanical properties as well as wear behaviors of the two HEA coatings were studied.With Si element addition,the surface and cross-sectional microstructure of HEA coating are refined,and it was found that both HEA coatings have a body-centered cubic structure,and the X-ray diffraction peaks of AlCoCrFeNiSi HEA coating deviate to the right.The microhardness,bonding strength nanohardness and elastic modulus of AlCoCrFeNi HEA coating increased with addition of Si element due to the fact that Si promotes uniformly distribution of other elements.In terms of wear properties,coefficient of friction and the wear rate were reduced with Si element addition,and the two HEA coatings have similar wear mechanism at the same loads.And at lower loads,the wear mechanism is abrasive wear,adhesive and slight oxidative wear,it is turn to oxidative wear and severe abrasive wear while the load is increased.The AlCoCrFeNiSi HEA coating has a higher corrosion potential and a lower corrosion current density,indicating improved corrosion resistance.This enhancement is attributed to the presence of Si,which reduces interatomic spacing and results in a more compact atomic arrangement.Consequently,element migration and chemical reactions are reduced,leading to the formation of a denser and more uniform passivation film.展开更多
针对玉米杂草识别过程中因光照变化导致识别精确度低及漏检问题,该研究以幼苗期玉米及其伴生杂草为研究对象,设计一种基于WEED-YOLOv10的玉米杂草检测方法。首先,通过无人机快速采集田间高分辨率图像构建了玉米杂草数据集;其次,以YOLOv...针对玉米杂草识别过程中因光照变化导致识别精确度低及漏检问题,该研究以幼苗期玉米及其伴生杂草为研究对象,设计一种基于WEED-YOLOv10的玉米杂草检测方法。首先,通过无人机快速采集田间高分辨率图像构建了玉米杂草数据集;其次,以YOLOv10n为基线网络,将骨干网络替换为ConvNeXtV2以增强特征提取能力;继而,为避免因模块拼接可能带来的信息冗余或丢失问题提升对光照干扰的鲁棒性,嵌入CBAM注意力机制;然后,引入SlimNeck结构优化网络计算效率,有效平衡了模型计算资源消耗与特征表征能力;最后,使用Focaler-EIoU损失函数进一步提高模型定位精度。试验结果表明,WEED-YOLOv10在精确率、召回率、mAP@50、mAP@50:95和F1分数上分别达到85.4%、88.1%、90.9%、48.5%和86.7%,较基准模型分别提升了2.4、2.9、3.5、7.0、2.6个百分点,各项精度指标均优于其他对比模型,部署在NVIDIA Jetson orin NX上的图片推理速度达到28.7帧/s,实现了检测速度与精度的平衡。进一步地,基于WEED-YOLOv10开发对靶喷药系统,该系统实时捕捉并解析来自模型的识别信号,实现对除草喷施装置的精准调控。田间试验结果显示,对靶喷药系统施药准确率为93.7%,喷洒覆盖率为90.5%,对靶偏差为1.45cm,杂草实时检测速度为20.1帧/s,实现了自动化的玉米田间除草作业。该研究为复杂光照场景下农田杂草治理提供了可靠的技术方案,对推动农业智能化作业具有重要意义。展开更多
针对复杂果园环境下实时动态差分(real-time kinematic,RTK)信号易丢失以及传统激光同步定位与建图(simultaneous localization and mapping,SLAM)方法在复杂果园中因几何特征离散不稳定及局部环境相似度高导致的定位精度偏低的问题,该...针对复杂果园环境下实时动态差分(real-time kinematic,RTK)信号易丢失以及传统激光同步定位与建图(simultaneous localization and mapping,SLAM)方法在复杂果园中因几何特征离散不稳定及局部环境相似度高导致的定位精度偏低的问题,该研究提出了一种融合树干几何特征与改进回环描述子的果园喷雾机器人高精度激光惯性定位与建图方法。该方法引入树干几何特征提取算法,利用树干表面的高稳定性构建高置信度的点面约束,强化前端配准精度;后端利用果园树木空间分布特征,设计基于树干拓扑结构的回环描述子与双重判别机制,有效检测回环并消除累积误差。在BotanicGarden公有数据集和自制苗圃.数据集上的试验表明,该方法在复杂果园场景下的定位精度较FAST-LIO2和SC-LIO-SAM分别提升约42.4%和48.3%,可为果园喷雾机器人高精度自主作业提供可靠的定位支持。展开更多
针对当前无人机喷药喷施不均匀、雾滴飘移、肥药有效利用率低和浪费污染严重等问题,设计了一种基于果树冠层识别的植保无人机可变角度变量喷施装置。该装置通过摄像头采集果树冠层图像并传输至Jetson Orin Nano,利用ROI选取与子区间线...针对当前无人机喷药喷施不均匀、雾滴飘移、肥药有效利用率低和浪费污染严重等问题,设计了一种基于果树冠层识别的植保无人机可变角度变量喷施装置。该装置通过摄像头采集果树冠层图像并传输至Jetson Orin Nano,利用ROI选取与子区间线扫方法实现冠层边界与果树行宽度识别,识别结果传至STM32控制器,其中冠层边界信息用于调节喷头角度,像素占比信息用于调控喷头流量,流量计与磁编码器反馈信号经模糊PID算法处理,实现喷头角度与喷施量双闭环控制。经试验验证,果树冠层边界算法离线识别率为91.58%。台架试验结果表明,该方法在果树行宽度识别中平均误差为7.32%,线性拟合R^(2)=0.91;在喷雾验证中,当喷施角度大于靶区时,调节后可使靶区外沉积数量平均降低26.61个/cm^(2),雾滴沉积数量降低51.94%。当喷施角度小于靶区时,调节后可使靶区内外部雾滴沉积数量平均提升25.37个/cm^(2),雾滴沉积数量提高54.8%。核密度估计曲线更平滑,有效改善沉积分布均匀性。田间试验结果显示:统计检验结果为t=3.29、P=0.03,达到P<0.05的统计显著水平,装置开启状态下沉积效果更优,该方法实现了基于果树行宽度可变角度变量喷施控制,可有效提高雾滴利用率,为无人机果园精准施药提供技术支持。展开更多
基金supported by the Scientific Research Projects of the Education Department of Zhejiang Province(Grant No.Y202454744)the Ningbo Public Welfare Science and Technology Project(Grant No.2024S077)+1 种基金International Sci-tech Cooperation Projects under the“Innovation Yongjiang 2035”Key R&D Programme(No.2024H019)the Ningbo Key R&D Program(Grant No.2024Z287).
文摘The existing 2D settlement monitoring systems for utility tunnels are heavily reliant on manual interpretation of deformation data and empirical predictionmodels.Consequently,early anomalies(e.g.,minor cracks)are often misjudged,and warnings lag by about 24 h without automated spatial localization.This study establishes a technical framework for requirements analysis,architectural design,and data-integration protocols.Revit parametric modelling is used to build a 3D tunnel model with structural elements,pipelines and 18 monitoring points(for displacement and joint width).Custom Revit API code integrated real-time sensor data into the BIM platform via an automated pipeline.The system achieved a spatial accuracy of±1 mm in locating deformation hotspots.Notifications are triggered within 10 s of anomaly detection,and the system renders 3D risk propagation paths in real-time.Realtime 3D visualization of risk propagation paths is also facilitated.The efficacy of the solution was validated in a Ningbo utility tunnel project,where it was demonstrated that it eliminates human-dependent judgment errors and reduces warning latency by 99.9%compared to conventional methods.The BIM-IoT integrated approach,which enables millimetre-level precision in risk identification and near-instantaneous response,establishes a new paradigm for intelligent infrastructure safety management.
基金supported by the National Natural Science Foundation of China(No.51706105)。
文摘Al/NH_(4)CoF_(3)-Φ(Φ=0.5,1.0,1.5,2.0,and 3.0)binary composites and Al-NH_(4)CoF_(3)@P(VDF-HFP)ternary composites are fabricated via ultrasonication-assisted blending and electrostatic spraying.The effect of equivalence ratio(Φ)on the reaction properties is systematically investigated in the binary Al/NH_(4)CoF_(3)system.For ternary systems,electrostatic spraying allows both components to be efficiently encapsulated by P(VDF-HFP)and to achieve structural stabilization and enhanced reactivity through synergistic interfacial interactions.Morphological analysis using SEM/TEM revealed that P(VDF-HFP)formed a protective layer on Al and NH_(4)CoF_(3)particles,improving dispersion,hydrophobicity(water contact angle increased by 80.5%compared to physically mixed composites),and corrosion resistance.Thermal decomposition of NH_(4)CoF_(3)occurred at 265℃,releasing NH_(3)and HF,which triggered exothermic reactions with Al.The ternary composites exhibited a narrowed main reaction temperature range and concentrated heat release,attributed to improved interfacial contact and polymer decomposition.Combustion tests demonstrated that Al-NH_(4)CoF_(3)@P(VDF-HFP)achieved self-sustaining combustion.In addition,a simple validation was done by replacing the Al component in the aluminium-containing propellant,demonstrating its potential application in the propellant field.This work establishes a novel strategy for designing stable,high-energy composites with potential applications in advanced propulsion systems.
文摘Composite water samples taken from Owena Multi-purpose Dam in six sampling campaigns covering the wet and dry seasons were analyzed for physico-chemical and microbial characteristics using standard methods for the examination of water and wastewater jointly published by the American Public Health Association, American Water Works Association and Water Pollution Control Federation. Results showed significant (p < 0.05) seasonal variations in most measured parameters with few showing significant spatial variation. The characteristics of the water from the dam lake revealed an acceptable quality for most measured parameters with low chemical pollutants burden when compared with drinking water standards and water quality for aquaculture. However, high values of turbidity, colour, iron, manganese and microbial load were recorded compared with drinking water standards, which call for proper treatment of the water before distribution for public consumption.
文摘Designing of a multi-purpose plant as one of the well-known manufacturing systems is more challenging than other manufacturing systems. This paper applies a stochastic colored Petri net (CPN) to design and analyze multi-purpose plants. A simple approach is proposed to determine the utilization of shared resources and to reduce the equipment’s idle times. Three scenarios are presented to describe the proposed model. Generally, according to desire of a decision maker, different scenarios can be considered in the model to achieve to the expected design or plant configuration. The main characteristics of the proposed model are flexibility, the easiness of practical application and the simulation of the model in an easy way.
文摘The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The radial and poloidal electric fields （Sr, Ep） and ion saturation current （Is） are measured by multi-purpose probe （MPP）. This probe is fabricated and constructed for the first time in the IR-T1 tokamak. The most advantage of this probe is that the variations of Er and Ep can be measured in different radii at the single shot. Thus the information of different radii can be compared with high precision. The bias voltage is fixed at Vbias = 200 V and it has been applied with the limiter bias that is fixed in r/a = 0.9. Moreover, the phase difference between radial and poloidal electric fields, and temporal evolution of the RS .spectrum detected by MPP are calculated. RS magnitude on the edge （r/a = 0.9） is more than its value in the SOL （r/a = 1.02）. With the applied bias 200 V, ItS and the magnitude of the phase difference between Er and Ep are increased, while the radial turbulent transport is decreased simultaneously. Thus it can be concluded that RS affects radial turbulence. Temporal evolution of the RS spectrum shows that the frequency of RS is increased and reaches its highest value at r/a=0.9 in the presence of bias.
文摘Aimed at current deficiencies of multi-purpose guided missile kill probability model against gunship, the concept of the important coefficient of vulnerability blade unit is proposed in this paper. Laser fuze actuation model and warhead condition kill probability model of rotor blades are established by Monte Carlo method and kinetics theory with new ideas. Based on limited data, armor thickness of gunship is estimated, and a complete multi-purpose guided missile kill probability mathematical model is established, which provides necessary mathematical tool for the accurate and objective analysis of multi-purpose guided missile kill probability against gunship. Based on the establishment of the model, sensitivity analysis and optimal design of the main factors of multi-purpose guided missile kill probability are conducted, and the results show that the single multi-purpose guided missile lethality performance can be improved significantly by sensitivity analysis and optimization.
文摘To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.
基金National Natural Science Foundation of China(No.22275150)。
文摘To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20),NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method.The morphology,structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS),infrared spectroscopy(FT-IR),and simultaneous thermal analyzer(TG-DSC).Additionally,the combustion process of the samples was tested using a high-speed camera.The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size.The Si/NC/CL-20 composite explosive has better and more uniform sphericity,with an average particle size of 73.4 nm,compared to the NC/CL-20 composite explosive.The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method,achieves physically uniform distribution of the components including NC,CL-20,Si.The addition of Si promotes the thermal decomposition of CL-20.In comparison to the NC/CL-20 composite explosive,the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78 kJ/mol,and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12 K and 2.61 K,respectively.Furthermore,Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive,which shows that Si can improve the combustion performance of CL-20.
基金Design and Research of Intelligent Construction Device for the“Water-in-Sand”Process of High-Rise Building Exterior Wall(Project No.2022KQNCX189)。
文摘The spraying robot for building exterior walls is an innovative technology in the field of modern construction.This paper discusses its design structure,application cases,technical benefits,and industrial impacts.Research shows that this type of robot improves the efficiency and quality of exterior wall construction.Its intelligent design enhances operation accuracy and safety,reduces costs and risks,and strengthens application ability in complex environments,showing broad application prospects and symbolizing the development trend of intelligence and automation in the industry.In the future,it is necessary to strengthen its intelligence and adaptive ability further,explore multi-function design,promote automation technology,and ensure construction safety and economic benefits.
基金supported by the National Natural Science Foundation of China(Nos.52175196 and 52275218)the National Key R&D Program of China(No.2022YFB3706600).
文摘AlCoCrFeNi and AlCoCrFeNiSi high entropy alloy(HEA)coatings have been prepared by high velocity oxygen fuel spraying,and the microstructure,mechanical properties as well as wear behaviors of the two HEA coatings were studied.With Si element addition,the surface and cross-sectional microstructure of HEA coating are refined,and it was found that both HEA coatings have a body-centered cubic structure,and the X-ray diffraction peaks of AlCoCrFeNiSi HEA coating deviate to the right.The microhardness,bonding strength nanohardness and elastic modulus of AlCoCrFeNi HEA coating increased with addition of Si element due to the fact that Si promotes uniformly distribution of other elements.In terms of wear properties,coefficient of friction and the wear rate were reduced with Si element addition,and the two HEA coatings have similar wear mechanism at the same loads.And at lower loads,the wear mechanism is abrasive wear,adhesive and slight oxidative wear,it is turn to oxidative wear and severe abrasive wear while the load is increased.The AlCoCrFeNiSi HEA coating has a higher corrosion potential and a lower corrosion current density,indicating improved corrosion resistance.This enhancement is attributed to the presence of Si,which reduces interatomic spacing and results in a more compact atomic arrangement.Consequently,element migration and chemical reactions are reduced,leading to the formation of a denser and more uniform passivation film.
文摘针对玉米杂草识别过程中因光照变化导致识别精确度低及漏检问题,该研究以幼苗期玉米及其伴生杂草为研究对象,设计一种基于WEED-YOLOv10的玉米杂草检测方法。首先,通过无人机快速采集田间高分辨率图像构建了玉米杂草数据集;其次,以YOLOv10n为基线网络,将骨干网络替换为ConvNeXtV2以增强特征提取能力;继而,为避免因模块拼接可能带来的信息冗余或丢失问题提升对光照干扰的鲁棒性,嵌入CBAM注意力机制;然后,引入SlimNeck结构优化网络计算效率,有效平衡了模型计算资源消耗与特征表征能力;最后,使用Focaler-EIoU损失函数进一步提高模型定位精度。试验结果表明,WEED-YOLOv10在精确率、召回率、mAP@50、mAP@50:95和F1分数上分别达到85.4%、88.1%、90.9%、48.5%和86.7%,较基准模型分别提升了2.4、2.9、3.5、7.0、2.6个百分点,各项精度指标均优于其他对比模型,部署在NVIDIA Jetson orin NX上的图片推理速度达到28.7帧/s,实现了检测速度与精度的平衡。进一步地,基于WEED-YOLOv10开发对靶喷药系统,该系统实时捕捉并解析来自模型的识别信号,实现对除草喷施装置的精准调控。田间试验结果显示,对靶喷药系统施药准确率为93.7%,喷洒覆盖率为90.5%,对靶偏差为1.45cm,杂草实时检测速度为20.1帧/s,实现了自动化的玉米田间除草作业。该研究为复杂光照场景下农田杂草治理提供了可靠的技术方案,对推动农业智能化作业具有重要意义。
文摘针对复杂果园环境下实时动态差分(real-time kinematic,RTK)信号易丢失以及传统激光同步定位与建图(simultaneous localization and mapping,SLAM)方法在复杂果园中因几何特征离散不稳定及局部环境相似度高导致的定位精度偏低的问题,该研究提出了一种融合树干几何特征与改进回环描述子的果园喷雾机器人高精度激光惯性定位与建图方法。该方法引入树干几何特征提取算法,利用树干表面的高稳定性构建高置信度的点面约束,强化前端配准精度;后端利用果园树木空间分布特征,设计基于树干拓扑结构的回环描述子与双重判别机制,有效检测回环并消除累积误差。在BotanicGarden公有数据集和自制苗圃.数据集上的试验表明,该方法在复杂果园场景下的定位精度较FAST-LIO2和SC-LIO-SAM分别提升约42.4%和48.3%,可为果园喷雾机器人高精度自主作业提供可靠的定位支持。
文摘针对当前无人机喷药喷施不均匀、雾滴飘移、肥药有效利用率低和浪费污染严重等问题,设计了一种基于果树冠层识别的植保无人机可变角度变量喷施装置。该装置通过摄像头采集果树冠层图像并传输至Jetson Orin Nano,利用ROI选取与子区间线扫方法实现冠层边界与果树行宽度识别,识别结果传至STM32控制器,其中冠层边界信息用于调节喷头角度,像素占比信息用于调控喷头流量,流量计与磁编码器反馈信号经模糊PID算法处理,实现喷头角度与喷施量双闭环控制。经试验验证,果树冠层边界算法离线识别率为91.58%。台架试验结果表明,该方法在果树行宽度识别中平均误差为7.32%,线性拟合R^(2)=0.91;在喷雾验证中,当喷施角度大于靶区时,调节后可使靶区外沉积数量平均降低26.61个/cm^(2),雾滴沉积数量降低51.94%。当喷施角度小于靶区时,调节后可使靶区内外部雾滴沉积数量平均提升25.37个/cm^(2),雾滴沉积数量提高54.8%。核密度估计曲线更平滑,有效改善沉积分布均匀性。田间试验结果显示:统计检验结果为t=3.29、P=0.03,达到P<0.05的统计显著水平,装置开启状态下沉积效果更优,该方法实现了基于果树行宽度可变角度变量喷施控制,可有效提高雾滴利用率,为无人机果园精准施药提供技术支持。
