In this study,for the first time a suitable pesticide residue detection system for dandelion(Taraxacum officinale L.)was established based on electronic nose to determine and study the concentration of pesticide resid...In this study,for the first time a suitable pesticide residue detection system for dandelion(Taraxacum officinale L.)was established based on electronic nose to determine and study the concentration of pesticide residue in dandelion.Dandelions were sprayed with different concentrations of pesticides(avermectin,trichlorfon,deltamethrin,and acetamiprid),respectively.Data collection was performed by application of an electronic nose equipped with 12 metal oxide semiconductor(MOS)sensors.Data analysis was conducted using different methods including BP neural network and random forest(RF)as well as the support vector machine(SVM).The results showed the superior effectiveness of SVM in discrimination and classification of non-exceeding maximum residue limits(MRLs)and exceeding MRLs standards.Moreover,the model trained by SVM has the best performance for the classification of pesticide categories in dandelion,and the classification accuracy was 91.7%.The results of this study can provide reference for further development and construction of efficient detection technology of pesticide residues based on electronic nose for agricultural products.展开更多
For the enhancement of heat transfer efficiency,a novel turbulator inspired by the morphology of barchan dunes,called the mimetic barchan dune(MBD)turbulator,is designed and evaluated in the simplified gas turbine tra...For the enhancement of heat transfer efficiency,a novel turbulator inspired by the morphology of barchan dunes,called the mimetic barchan dune(MBD)turbulator,is designed and evaluated in the simplified gas turbine transition section.By using computational fluid dynamics(CFD),the numerical simulations for comparison have been carried out,concluding the smooth thermal surface,a thermal surface with riblet-shaped turbulator and a thermal surface with MBD turbulator.Then,two indicators are investigated for evaluating the coolant performance which are the heat transfer efficiency(η)on the outlet and the pressure loss(ΔP)in the coolant chamber.The numerical results show that the coolant has the best heat transfer efficiency with less pressure loss in the coolant chamber with the MBD turbulator.Then,the effect of the MBD turbulator sizes on heat transfer efficiency is investigated.When the height of the MBD turbulator(h)is set at 8 mm,the maximum amount of heat that could be transfered by the coolant is up to566.2 K and the corresponding heat transfer efficiency is 26.62%.The detail flows have been shown to elucidate the function of the MBD surface which may greatly arouse more design for solving harsh circumstance.展开更多
基金supported by the National Natural Science Found of China(Grant No.51875245)the Science-Technology Development Plan Project of Jilin Province(Grant No.20210203099SF+4 种基金No.20210203004SF)the“13th Five-Year Plan”Scientific Research Foundation of the Education Department of Jilin Province(Grant No.JJKH20200871KJNo.JJKH20200870KJNo.JJKH20200334KJNo.JJKH20210338KJ).
文摘In this study,for the first time a suitable pesticide residue detection system for dandelion(Taraxacum officinale L.)was established based on electronic nose to determine and study the concentration of pesticide residue in dandelion.Dandelions were sprayed with different concentrations of pesticides(avermectin,trichlorfon,deltamethrin,and acetamiprid),respectively.Data collection was performed by application of an electronic nose equipped with 12 metal oxide semiconductor(MOS)sensors.Data analysis was conducted using different methods including BP neural network and random forest(RF)as well as the support vector machine(SVM).The results showed the superior effectiveness of SVM in discrimination and classification of non-exceeding maximum residue limits(MRLs)and exceeding MRLs standards.Moreover,the model trained by SVM has the best performance for the classification of pesticide categories in dandelion,and the classification accuracy was 91.7%.The results of this study can provide reference for further development and construction of efficient detection technology of pesticide residues based on electronic nose for agricultural products.
基金supported by the National Key R&D Program of China (No.2018YFB1105100)the National Natural Science Foundation of China (No.51975246)+2 种基金the Advanced Manufacturing Project of Provincial School Construction of Jilin Province (No. SXGJSF2017-2)the Program for JLU Science and Technology Innovative Research Team (2019TD-34)the China Postdoctoral Science Foundation Funded Project (No. 2016M590256)
文摘For the enhancement of heat transfer efficiency,a novel turbulator inspired by the morphology of barchan dunes,called the mimetic barchan dune(MBD)turbulator,is designed and evaluated in the simplified gas turbine transition section.By using computational fluid dynamics(CFD),the numerical simulations for comparison have been carried out,concluding the smooth thermal surface,a thermal surface with riblet-shaped turbulator and a thermal surface with MBD turbulator.Then,two indicators are investigated for evaluating the coolant performance which are the heat transfer efficiency(η)on the outlet and the pressure loss(ΔP)in the coolant chamber.The numerical results show that the coolant has the best heat transfer efficiency with less pressure loss in the coolant chamber with the MBD turbulator.Then,the effect of the MBD turbulator sizes on heat transfer efficiency is investigated.When the height of the MBD turbulator(h)is set at 8 mm,the maximum amount of heat that could be transfered by the coolant is up to566.2 K and the corresponding heat transfer efficiency is 26.62%.The detail flows have been shown to elucidate the function of the MBD surface which may greatly arouse more design for solving harsh circumstance.
