Self-regulating heating and self-powered flexibility are pivotal for future wearable devices.However,the low energy-conversion rate of wearable devices at low temperatures limits their application in plateaus and othe...Self-regulating heating and self-powered flexibility are pivotal for future wearable devices.However,the low energy-conversion rate of wearable devices at low temperatures limits their application in plateaus and other environments.This study introduces an azopolymer with remarkable semicrystallinity and reversible photoinduced solid-liquid transition ability that is obtained through copolymerization of azoben-zene(Azo)monomers and styrene.A composite of one such copolymer with an Azo:styrene molar ratio of 9:1(copolymer is denoted as PAzo9:1-co-polystyrene(PS))and nylon fabrics(NFs)is prepared(composite is denoted as PAzo9:1-co-PS@NF).PAzo9:1-co-PS@NF exhibits hydrophobicity and high wear resistance.Moreover,it shows good responsiveness(0.624 s^(−1))during isomerization under solid ultraviolet(UV)light(365 nm)with an energy density of 70.6 kJ kg^(−1).In addition,the open-circuit voltage,short-circuit current and quantity values of PAzo9:1-co-PS@NF exhibit small variations in a temperature range of−20℃ to 25℃ and remain at 170 V,5 μA,and 62 nC,respectively.Notably,the involved NFs were cut and sewn into gloves to be worn on a human hand model.When the model was exposed to both UV radiation and friction,the temperature of the finger coated with PAzo9:1-co-PS was approximately 6.0°C higher than that of the other parts.Therefore,developing triboelectric nanogenerators based on the in situ photothermal cycles of Azo in wearable devices is important to develop low-temperature self-regulating heating and self-powered flexible devices for extreme environments.展开更多
目的天然气加臭是保障天然气泄漏迅速识别和安全使用的重要手段,为保证加臭剂质量浓度符合标准规范且避免过量加臭,建立一种准确高效的分析方法对天然气中加臭剂进行检测。方法采用光离子化气相色谱法(gas chromatography with photoion...目的天然气加臭是保障天然气泄漏迅速识别和安全使用的重要手段,为保证加臭剂质量浓度符合标准规范且避免过量加臭,建立一种准确高效的分析方法对天然气中加臭剂进行检测。方法采用光离子化气相色谱法(gas chromatography with photoionization detection,GC-PID),设置操作流程,优选分析参数,通过实验室评价和现场应用,系统考察GC-PID法的有效性、抗干扰性、检出限、重复性、准确性和现场适用性,验证其对四氢噻吩和无硫加臭剂的检测能力。结果建立的方法对加臭剂具有高选择性,定量准确性高,在2.00~150.00 mg/m^(3)范围内,对四氢噻吩的相对标准偏差<1.5%,检出限为0.40 mg/m^(3)。GC-PID法具有良好的现场适用性,具有良好的数据准确性和稳定性。结论基于GC-PID法开发的该天然气中四氢噻吩和无硫加臭剂的检测方法,为加臭剂质量浓度的在线监测和便携检测提供了新途径,具有实际应用价值与推广前景。展开更多
Aiming to solve the steering instability and hysteresis of agricultural robots in the process of movement,a fusion PID control method of particle swarm optimization(PSO)and genetic algorithm(GA)was proposed.The fusion...Aiming to solve the steering instability and hysteresis of agricultural robots in the process of movement,a fusion PID control method of particle swarm optimization(PSO)and genetic algorithm(GA)was proposed.The fusion algorithm took advantage of the fast optimization ability of PSO to optimize the population screening link of GA.The Simulink simulation results showed that the convergence of the fitness function of the fusion algorithm was accelerated,the system response adjustment time was reduced,and the overshoot was almost zero.Then the algorithm was applied to the steering test of agricultural robot in various scenes.After modeling the steering system of agricultural robot,the steering test results in the unloaded suspended state showed that the PID control based on fusion algorithm reduced the rise time,response adjustment time and overshoot of the system,and improved the response speed and stability of the system,compared with the artificial trial and error PID control and the PID control based on GA.The actual road steering test results showed that the PID control response rise time based on the fusion algorithm was the shortest,about 4.43 s.When the target pulse number was set to 100,the actual mean value in the steady-state regulation stage was about 102.9,which was the closest to the target value among the three control methods,and the overshoot was reduced at the same time.The steering test results under various scene states showed that the PID control based on the proposed fusion algorithm had good anti-interference ability,it can adapt to the changes of environment and load and improve the performance of the control system.It was effective in the steering control of agricultural robot.This method can provide a reference for the precise steering control of other robots.展开更多
基金supported by the China Postdoctoral Science Foundation(No.2023M732344)the National Natural Science Foundation of China(Nos.51973119,52327802,52173078)+4 种基金Shenzhen Key Laboratory of Photonics and Biophotonics(ZDSYS20210623092006020)Shenzhen Key Laboratory for Low-carbon Natural Science Foundation of Guangdong Province(No.2024A1515010639)Construction Material and Technology(No.ZDSYS20220606100406016)National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment(Shenzhen)(No.868-000003010103)Joint Funds of Ministry of Education(No.8091B022225).
文摘Self-regulating heating and self-powered flexibility are pivotal for future wearable devices.However,the low energy-conversion rate of wearable devices at low temperatures limits their application in plateaus and other environments.This study introduces an azopolymer with remarkable semicrystallinity and reversible photoinduced solid-liquid transition ability that is obtained through copolymerization of azoben-zene(Azo)monomers and styrene.A composite of one such copolymer with an Azo:styrene molar ratio of 9:1(copolymer is denoted as PAzo9:1-co-polystyrene(PS))and nylon fabrics(NFs)is prepared(composite is denoted as PAzo9:1-co-PS@NF).PAzo9:1-co-PS@NF exhibits hydrophobicity and high wear resistance.Moreover,it shows good responsiveness(0.624 s^(−1))during isomerization under solid ultraviolet(UV)light(365 nm)with an energy density of 70.6 kJ kg^(−1).In addition,the open-circuit voltage,short-circuit current and quantity values of PAzo9:1-co-PS@NF exhibit small variations in a temperature range of−20℃ to 25℃ and remain at 170 V,5 μA,and 62 nC,respectively.Notably,the involved NFs were cut and sewn into gloves to be worn on a human hand model.When the model was exposed to both UV radiation and friction,the temperature of the finger coated with PAzo9:1-co-PS was approximately 6.0°C higher than that of the other parts.Therefore,developing triboelectric nanogenerators based on the in situ photothermal cycles of Azo in wearable devices is important to develop low-temperature self-regulating heating and self-powered flexible devices for extreme environments.
文摘Aiming to solve the steering instability and hysteresis of agricultural robots in the process of movement,a fusion PID control method of particle swarm optimization(PSO)and genetic algorithm(GA)was proposed.The fusion algorithm took advantage of the fast optimization ability of PSO to optimize the population screening link of GA.The Simulink simulation results showed that the convergence of the fitness function of the fusion algorithm was accelerated,the system response adjustment time was reduced,and the overshoot was almost zero.Then the algorithm was applied to the steering test of agricultural robot in various scenes.After modeling the steering system of agricultural robot,the steering test results in the unloaded suspended state showed that the PID control based on fusion algorithm reduced the rise time,response adjustment time and overshoot of the system,and improved the response speed and stability of the system,compared with the artificial trial and error PID control and the PID control based on GA.The actual road steering test results showed that the PID control response rise time based on the fusion algorithm was the shortest,about 4.43 s.When the target pulse number was set to 100,the actual mean value in the steady-state regulation stage was about 102.9,which was the closest to the target value among the three control methods,and the overshoot was reduced at the same time.The steering test results under various scene states showed that the PID control based on the proposed fusion algorithm had good anti-interference ability,it can adapt to the changes of environment and load and improve the performance of the control system.It was effective in the steering control of agricultural robot.This method can provide a reference for the precise steering control of other robots.
