In 1995,Yu et al.[1]first reported bulk-heterojunction(BHJ)solar cells with a conjugated polymer donor and a fullerene acceptor as the active materials.From then on,BHJ organic solar cells(OSCs)have attracted academic...In 1995,Yu et al.[1]first reported bulk-heterojunction(BHJ)solar cells with a conjugated polymer donor and a fullerene acceptor as the active materials.From then on,BHJ organic solar cells(OSCs)have attracted academic and industrial interests due to the advantages like lightweight,flexibility and roll-to-roll fabrication.Nowadays,17%power conversion efficiencies(PCEs)have been achieved in the state-of-the-art OSCs[2,3].The remarkable progress in OSCs relies on the continuously emerging new materials and device fabrication technologies,and the understanding on film morphology and device physics[4,5].展开更多
Nowadays,wide-bandgap(WBG)copolymers attract great attention in the field of organic photovoltaics[1].They are ideal electron-donating partners for low-bandgap small molecule acceptors[2-12].With good energy levels ma...Nowadays,wide-bandgap(WBG)copolymers attract great attention in the field of organic photovoltaics[1].They are ideal electron-donating partners for low-bandgap small molecule acceptors[2-12].With good energy levels matching,the blend of WBG copolymer donor and small molecule acceptor can harvest most of the sunlight and deliver high power conversion efficiencies(PCEs)in solar cells.PCEs higher than 16%have been achieved[13-15].WBG copolymers especially those with ultra-wide bandgaps(i.e.,optical bandgap(Eg opt)>2.07 eV,absorption onset<600 nm)can find applications in ternary solar cells[16]and tandem solar cells[17].Currently,ultra-WBG copolymer donors are less efficient,generally giving PCEs below 13%[18].Designing highly efficient ultra-WBG copolymers is needed.In this work,we use fluorine-and alkoxyl-substituted benzene(FAB)as the building block to construct ultra-WBG copolymer donors.展开更多
Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching （plastic film on sowing, as well as plastic film on flat soil and hole sowing） and chemicals （a drou...Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching （plastic film on sowing, as well as plastic film on flat soil and hole sowing） and chemicals （a drought resistant agent and a water- retaining agent） on growth, photosynthetic rate, yield, and water use efficiency （WUE） of spring millet （Setaria italica L.）. The experimental results showed that water-collecting and -retaining techniques can effectively increase soil moisture content, the leaf photosynthetic rate and crop growth. Due to increased soil moisture under the plastic-covered ridge and furrow water-collecting in July and August, dry matter and plant height had a increase at the booting stage （late growth advantage）. However, the plastic-covered flat soil and hole sowing reduced soil evaporation during early growth, the increase of dry matter and plant height appeared at the seedling stage （early growth advantage）. Plastic-covered ridge and furrow sowing supplemented with chemical reagents had significant positive effects on water collection and soil moisture retention. Improvement of soil moisture resulted into the increase of the photosynthetic rate, dry matter accumulation yield and WUE. The water-collecting and -retaining techniques can improve WUE and enhance crop yield. Correlation analysis demonstrated that the photosynthetic rate under the water-collecting and -retaining techniques was significantly associated with the soil moisture, but had no significant relationship with leaf chlorophyll content. Plastic- covered ridge and furrow sowing supplemented with chemical reagents increased the yield and WUE by 114% and 8.16 kg ha-1 mm-1, respectively, compared with the control; while without the chemical reagents the yield and WUE were 95% and 7.42 kg ha-1 mm-1 higher, respectively, than those of the control.展开更多
[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavo...[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavonoid glycosides were isolated and purified from the ethanol alcoholic extract of the roots of Liliaceae plant Chlorophytum comosum by silica gel column chromatography,macroporous resin column chromatography,Sephadex LH-20,and reverse column chromatography(ODS).The inhibitory activity of flavonoid glycosides on human nasopharyngeal carcinoma cells was analyzed by CCK-8 method,and the potential mechanism was preliminarily analyzed by molecular docking.[Results]Two flavonoid glycosides were identified as isovitexin 2″-0-rhamnoside and 7-2″-di-O-β-glucopyranosylisovitexin.Two flavonoid glycosides showed promising inhibitory effect on human nasopharyngeal carcinoma cell line 5-8F,with IC_(50) values of 24.8 and 27.5μmol/L,respectively.Molecular docking results showed that the potential targets of two flavonoid glycosides include CyclinD1,Bcl-2β-Catenin,ILK,TGF-β,in addition,two glycosides showed higher predicted binding affinity towards CyclinD1,which verifies the cytotoxicity of the two compounds on human nasopharyngeal carcinoma cell line 5-8F in vitro.[Conclusions]Two flavonoid glycosides are the active molecules in Chlorophytum comosum that can inhibit the proliferation of human nasopharyngeal carcinoma cells,and have the potential to be used in the research and development of anti nasopharyngeal carcinoma drugs.展开更多
Electromagnetically induced transparency(EIT)is a coherent optical process that provides a narrow transparent peak within a broad absorption line in an atomic medium.All-dielectric metasurface analogues of EIT have en...Electromagnetically induced transparency(EIT)is a coherent optical process that provides a narrow transparent peak within a broad absorption line in an atomic medium.All-dielectric metasurface analogues of EIT have enabled new developments in the nanophotonics field for obtaining smaller,more effective slow-light devices and highly sensitive detectors without a quantum approach.However,the dynamic control of the EIT response of all-dielectric metasurfaces has been rarely reported hitherto for the near-infrared(N-IR)region,although a broader range of applications will be enabled by a reconfigurable EIT system.In this study,we realise a chalcogenide(germanium antimony telluride,GST)metasurface,which possesses a dynamically tunable EIT response by optically driving the amorphous-crystalline phase change in the GST medium.Only a few tens of nanometres thick,the nanostructured GST film exhibits Mie resonances that are spectrally modified via laser-induced phase transitions,offering a high relative modulation contrast of 80%in the N-IR region.Moreover,an extreme dispersion that results in the‘slow light’behaviour is observed within this transparency‘window’.Furthermore,the group delay of the N-IR beam switches reversibly under the phase transition.The measurement is consistent with both numerical simulation results and phenomenological modelling.Our work facilitates the development of new types of compact ultrafast N-IR holograms,filtering,and ultrasensitive detectors.展开更多
A facile method to fabricate tough and highly stretchable polyacrylamide （PAM） nanocomposite physical hydrogel （NCP gel） was proposed. The hydrogels are dually crosslinked single network with the PAM grafted vinyl...A facile method to fabricate tough and highly stretchable polyacrylamide （PAM） nanocomposite physical hydrogel （NCP gel） was proposed. The hydrogels are dually crosslinked single network with the PAM grafted vinyl hybrid silica nanoparticles （VSNPs） as the analogous covalent crosslinking points and the reversible hydrogen bonds among the PAM chains as the physical crosslinking points. In order to further elucidate the toughening mechanism of the PAM NCP gel, especially to understand the role of the dual crosslinking points, the PAM hybrid hydrogels （H gels） and a series of poly（acrylamide-co-dimethylacrylamide） （P（AM-co-DMAA）） NCP gels were designed and fabricated. Their mechanical properties were compared with those of the PAM NCP gels. The PAM H gels are prepared by simply mixing the PAM chains with bare silica nanoparticles （SNPs）. Relative to the poor mechanical properties of the PAM H gel, the PAM NCP gel is remarkably tough and stretchable and also generates large number of micro-cracks to stop notch propagation, indicating the important role of PAM grafted VSNPs in toughening the NCP gel. In the P（AM-co-DMAA） NCP gels, the P（AM-co- DMAA） chains are grafted on VSNPs and the polydimethylacrylamide （PDMAA） only forms very weak hydrogen bonds between themselves. It is found that mechanical properties of the PAM NCP gel, such as the tensile strength and the elongation at break, are enhanced significantly, but those of the P（AM-co-DMAA） NCP gels decreased rapidly with decreasing AM content. This result reveals the role of the hydrogen bonds among the grafted polymer chains as the physical crosslinking points in toughening the NCP gel.展开更多
The slow oxygen reduction process at the cathode and the scarcity of platinum-based metals lead to limited applications in fuel cells and metal-air cells.Recently,transition metal and nitrogen co-doped carbon-based ca...The slow oxygen reduction process at the cathode and the scarcity of platinum-based metals lead to limited applications in fuel cells and metal-air cells.Recently,transition metal and nitrogen co-doped carbon-based catalysts(M–N–C)are regarded as the most prospective non-precious metal catalysts for future fuel cell applications.It is verified theoretically and experimentally that the metal and nitrogen coordination structure is the main catalytic activity center of oxygen reduction reaction(ORR),so constructing M–N–C materials with high available surface area and structural stability is an effective way to accelerate ORR.Herein,we deliberately synthesize a one-dimensional ZIF structure to fabricate one-dimensional porous Fe–N–C nanostick via two-step pyrolysis.Excitingly,the as-synthesized exhibited an outstanding ORR activity in alkaline medium(E_(1/2)of 0.928 V),as well as superior stability(only changed 7 mV after 10,000 cycles in alkaline medium).Our results show that the reduction of electrocatalyst dimensionality can promote mass transport and increase the accessibility of active sites,thus optimizing their performance in ORR.This work is a good demonstration of the importance of a rational design of catalyst structure for efficient ORR.展开更多
Sustainable acquisition of bioactive compounds from biomass-based platform molecules is a green alternative for existing CO_(2)-emitting fossil-fuel technologies.Herein,a core–shell magnetic biocarbon catalyst functi...Sustainable acquisition of bioactive compounds from biomass-based platform molecules is a green alternative for existing CO_(2)-emitting fossil-fuel technologies.Herein,a core–shell magnetic biocarbon catalyst functionalized with sulfonic acid(Fe3O4@SiO_(2)@chitosan-SO_(3)H,MBC-SO_(3)H)was prepared to be efficient for the synthesis of various N-substituted pyrroles(up to 99% yield)from bio-based hexanedione and amines under mild conditions.The abundance of Bronsted acid sites in the MBC-SO_(3)H ensured smooth condensation of 2,5-hexanedione with a variety of amines to produce N-substituted pyrroles.The reaction was illustrated to follow the conventional Pall-Knorr coupling pathway,which includes three cascade reaction steps:amination,loop closure and dehydration.The prepared MBC-SO_(3)H catalyst could effectively activate 2,5-hexanedione,thus weakening the dependence of the overall conversion process on the amine nucleophilicity.The influence of different factors(e.g.,reaction temperature,time,amount of catalyst,molar ratio of substrates,and solvent type)on the reaction activity and selectivity were investigated comprehensively.Moreover,the MBC-SO_(3)H possessed excellent thermochemical stability,reusability,and easy separation due to the presence of magnetic core-shell structures.Notably,there was no activity attenuation after 5 consecutive catalytic experiments.This work demonstrates a wide range of potential applications of developing functionalized core-shell magnetic materials to construct bioactive backbones from biomass-based platform molecules.展开更多
Aiming to solve problems in organic rice weeding a type of post-seat weeding machine was designed for rice paddies.The differences in the strengths and lengths of the root systems between the rice seedlings and the we...Aiming to solve problems in organic rice weeding a type of post-seat weeding machine was designed for rice paddies.The differences in the strengths and lengths of the root systems between the rice seedlings and the weeds were studied,and the motion track of the weeding wheel was analyzed to obtain the structural parameters of the weeding wheel.Then,the structural model of the weeding wheel was designed.The interaction process between the weeding wheel and soil in the paddy fields was simulated and analyzed based on the discrete element method,so as to investigate the working resistance change tendency of the weeding wheel and the orderliness of the soil disturbances.An orthogonal test was designed in this study,with three factors:the hoeing depth,the rotation rate of the weeding wheel,and the forward speed of the device.The influences of different operation parameters of the weeding machine on the weeding torque and soil disturbance speed were obtained based on a variance analysis of the test results.A multi-index comprehensive weighted scoring method was used to evaluate the simulation results.A soil bin test was conducted to verify the simulation results.Field experiments were carried out to test the working performance of the weeding machine.The comprehensive scoring results indicated that a better working performance of the weeding operation could be obtained when the hoeing depth was 50 mm,the rotation rate of the weeding wheel was 240 r/min,and the forward speed was 0.6 m/s.The results of the soil bin test were consistent with the simulation results.The results of the field experiment revealed that the weeding machine met the requirements for organic rice weeding.These results can provide a reference for the design of weeding machines for paddy fields.展开更多
基金the National Key Research and Development Program of China (2017YFA0206600)the National Natural Science Foundation of China (51773045, 21572041, 21772030 and 51922032)the Youth Association for Promoting Innovation (CAS) for financial support.
文摘In 1995,Yu et al.[1]first reported bulk-heterojunction(BHJ)solar cells with a conjugated polymer donor and a fullerene acceptor as the active materials.From then on,BHJ organic solar cells(OSCs)have attracted academic and industrial interests due to the advantages like lightweight,flexibility and roll-to-roll fabrication.Nowadays,17%power conversion efficiencies(PCEs)have been achieved in the state-of-the-art OSCs[2,3].The remarkable progress in OSCs relies on the continuously emerging new materials and device fabrication technologies,and the understanding on film morphology and device physics[4,5].
基金the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21572041,21772030 and 51922032)the Youth Association for Promoting Innovation(CAS)for financial support
文摘Nowadays,wide-bandgap(WBG)copolymers attract great attention in the field of organic photovoltaics[1].They are ideal electron-donating partners for low-bandgap small molecule acceptors[2-12].With good energy levels matching,the blend of WBG copolymer donor and small molecule acceptor can harvest most of the sunlight and deliver high power conversion efficiencies(PCEs)in solar cells.PCEs higher than 16%have been achieved[13-15].WBG copolymers especially those with ultra-wide bandgaps(i.e.,optical bandgap(Eg opt)>2.07 eV,absorption onset<600 nm)can find applications in ternary solar cells[16]and tandem solar cells[17].Currently,ultra-WBG copolymer donors are less efficient,generally giving PCEs below 13%[18].Designing highly efficient ultra-WBG copolymers is needed.In this work,we use fluorine-and alkoxyl-substituted benzene(FAB)as the building block to construct ultra-WBG copolymer donors.
基金the National Natural Science Foundation of China (30300213 and 30070439)the Program for New Century Excellent Talents in University, China (NCET-07-0700)
文摘Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching （plastic film on sowing, as well as plastic film on flat soil and hole sowing） and chemicals （a drought resistant agent and a water- retaining agent） on growth, photosynthetic rate, yield, and water use efficiency （WUE） of spring millet （Setaria italica L.）. The experimental results showed that water-collecting and -retaining techniques can effectively increase soil moisture content, the leaf photosynthetic rate and crop growth. Due to increased soil moisture under the plastic-covered ridge and furrow water-collecting in July and August, dry matter and plant height had a increase at the booting stage （late growth advantage）. However, the plastic-covered flat soil and hole sowing reduced soil evaporation during early growth, the increase of dry matter and plant height appeared at the seedling stage （early growth advantage）. Plastic-covered ridge and furrow sowing supplemented with chemical reagents had significant positive effects on water collection and soil moisture retention. Improvement of soil moisture resulted into the increase of the photosynthetic rate, dry matter accumulation yield and WUE. The water-collecting and -retaining techniques can improve WUE and enhance crop yield. Correlation analysis demonstrated that the photosynthetic rate under the water-collecting and -retaining techniques was significantly associated with the soil moisture, but had no significant relationship with leaf chlorophyll content. Plastic- covered ridge and furrow sowing supplemented with chemical reagents increased the yield and WUE by 114% and 8.16 kg ha-1 mm-1, respectively, compared with the control; while without the chemical reagents the yield and WUE were 95% and 7.42 kg ha-1 mm-1 higher, respectively, than those of the control.
基金Supported by Youth Fund Project of Zhaoqing University(QZ202235)Zhaoqing Science and Technology Plan Project(2022040311011).
文摘[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavonoid glycosides were isolated and purified from the ethanol alcoholic extract of the roots of Liliaceae plant Chlorophytum comosum by silica gel column chromatography,macroporous resin column chromatography,Sephadex LH-20,and reverse column chromatography(ODS).The inhibitory activity of flavonoid glycosides on human nasopharyngeal carcinoma cells was analyzed by CCK-8 method,and the potential mechanism was preliminarily analyzed by molecular docking.[Results]Two flavonoid glycosides were identified as isovitexin 2″-0-rhamnoside and 7-2″-di-O-β-glucopyranosylisovitexin.Two flavonoid glycosides showed promising inhibitory effect on human nasopharyngeal carcinoma cell line 5-8F,with IC_(50) values of 24.8 and 27.5μmol/L,respectively.Molecular docking results showed that the potential targets of two flavonoid glycosides include CyclinD1,Bcl-2β-Catenin,ILK,TGF-β,in addition,two glycosides showed higher predicted binding affinity towards CyclinD1,which verifies the cytotoxicity of the two compounds on human nasopharyngeal carcinoma cell line 5-8F in vitro.[Conclusions]Two flavonoid glycosides are the active molecules in Chlorophytum comosum that can inhibit the proliferation of human nasopharyngeal carcinoma cells,and have the potential to be used in the research and development of anti nasopharyngeal carcinoma drugs.
基金T.C.acknowledges support from the National Key Research and Development Program of China(2020YFA0714504,2019YFA0709100).
文摘Electromagnetically induced transparency(EIT)is a coherent optical process that provides a narrow transparent peak within a broad absorption line in an atomic medium.All-dielectric metasurface analogues of EIT have enabled new developments in the nanophotonics field for obtaining smaller,more effective slow-light devices and highly sensitive detectors without a quantum approach.However,the dynamic control of the EIT response of all-dielectric metasurfaces has been rarely reported hitherto for the near-infrared(N-IR)region,although a broader range of applications will be enabled by a reconfigurable EIT system.In this study,we realise a chalcogenide(germanium antimony telluride,GST)metasurface,which possesses a dynamically tunable EIT response by optically driving the amorphous-crystalline phase change in the GST medium.Only a few tens of nanometres thick,the nanostructured GST film exhibits Mie resonances that are spectrally modified via laser-induced phase transitions,offering a high relative modulation contrast of 80%in the N-IR region.Moreover,an extreme dispersion that results in the‘slow light’behaviour is observed within this transparency‘window’.Furthermore,the group delay of the N-IR beam switches reversibly under the phase transition.The measurement is consistent with both numerical simulation results and phenomenological modelling.Our work facilitates the development of new types of compact ultrafast N-IR holograms,filtering,and ultrasensitive detectors.
基金financially supported by the National Natural Science Foundation of China(Nos.21474058 and 51633003)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(No.LK1404)+1 种基金Tsinghua University Scientific Research Project(No.2014Z22069)State Key Laboratory of Organic-Inorganic Composites,Beijing University of Chemical Technology(No.OIC-201601006)
文摘A facile method to fabricate tough and highly stretchable polyacrylamide （PAM） nanocomposite physical hydrogel （NCP gel） was proposed. The hydrogels are dually crosslinked single network with the PAM grafted vinyl hybrid silica nanoparticles （VSNPs） as the analogous covalent crosslinking points and the reversible hydrogen bonds among the PAM chains as the physical crosslinking points. In order to further elucidate the toughening mechanism of the PAM NCP gel, especially to understand the role of the dual crosslinking points, the PAM hybrid hydrogels （H gels） and a series of poly（acrylamide-co-dimethylacrylamide） （P（AM-co-DMAA）） NCP gels were designed and fabricated. Their mechanical properties were compared with those of the PAM NCP gels. The PAM H gels are prepared by simply mixing the PAM chains with bare silica nanoparticles （SNPs）. Relative to the poor mechanical properties of the PAM H gel, the PAM NCP gel is remarkably tough and stretchable and also generates large number of micro-cracks to stop notch propagation, indicating the important role of PAM grafted VSNPs in toughening the NCP gel. In the P（AM-co-DMAA） NCP gels, the P（AM-co- DMAA） chains are grafted on VSNPs and the polydimethylacrylamide （PDMAA） only forms very weak hydrogen bonds between themselves. It is found that mechanical properties of the PAM NCP gel, such as the tensile strength and the elongation at break, are enhanced significantly, but those of the P（AM-co-DMAA） NCP gels decreased rapidly with decreasing AM content. This result reveals the role of the hydrogen bonds among the grafted polymer chains as the physical crosslinking points in toughening the NCP gel.
基金the National Natural Science Foundation of China(22071202,21931009,and 21721001).
文摘The slow oxygen reduction process at the cathode and the scarcity of platinum-based metals lead to limited applications in fuel cells and metal-air cells.Recently,transition metal and nitrogen co-doped carbon-based catalysts(M–N–C)are regarded as the most prospective non-precious metal catalysts for future fuel cell applications.It is verified theoretically and experimentally that the metal and nitrogen coordination structure is the main catalytic activity center of oxygen reduction reaction(ORR),so constructing M–N–C materials with high available surface area and structural stability is an effective way to accelerate ORR.Herein,we deliberately synthesize a one-dimensional ZIF structure to fabricate one-dimensional porous Fe–N–C nanostick via two-step pyrolysis.Excitingly,the as-synthesized exhibited an outstanding ORR activity in alkaline medium(E_(1/2)of 0.928 V),as well as superior stability(only changed 7 mV after 10,000 cycles in alkaline medium).Our results show that the reduction of electrocatalyst dimensionality can promote mass transport and increase the accessibility of active sites,thus optimizing their performance in ORR.This work is a good demonstration of the importance of a rational design of catalyst structure for efficient ORR.
基金funded by the Guizhou Provincial S&T Project(ZK[2022]011)Guizhou Natural Science Foundation(20201Y182)College Students’Innovation and Entrepreneurship Training Program(S202110657036).
文摘Sustainable acquisition of bioactive compounds from biomass-based platform molecules is a green alternative for existing CO_(2)-emitting fossil-fuel technologies.Herein,a core–shell magnetic biocarbon catalyst functionalized with sulfonic acid(Fe3O4@SiO_(2)@chitosan-SO_(3)H,MBC-SO_(3)H)was prepared to be efficient for the synthesis of various N-substituted pyrroles(up to 99% yield)from bio-based hexanedione and amines under mild conditions.The abundance of Bronsted acid sites in the MBC-SO_(3)H ensured smooth condensation of 2,5-hexanedione with a variety of amines to produce N-substituted pyrroles.The reaction was illustrated to follow the conventional Pall-Knorr coupling pathway,which includes three cascade reaction steps:amination,loop closure and dehydration.The prepared MBC-SO_(3)H catalyst could effectively activate 2,5-hexanedione,thus weakening the dependence of the overall conversion process on the amine nucleophilicity.The influence of different factors(e.g.,reaction temperature,time,amount of catalyst,molar ratio of substrates,and solvent type)on the reaction activity and selectivity were investigated comprehensively.Moreover,the MBC-SO_(3)H possessed excellent thermochemical stability,reusability,and easy separation due to the presence of magnetic core-shell structures.Notably,there was no activity attenuation after 5 consecutive catalytic experiments.This work demonstrates a wide range of potential applications of developing functionalized core-shell magnetic materials to construct bioactive backbones from biomass-based platform molecules.
基金The project was supported by the National Natural Science Foundation of China(Grant No.51475002)the Major Science and Technology projects of Anhui Province(Grant No.17030701046)the Natural Science Foundation of Anhui Province(Grant No.2008085QE270,1808085QE171).
文摘Aiming to solve problems in organic rice weeding a type of post-seat weeding machine was designed for rice paddies.The differences in the strengths and lengths of the root systems between the rice seedlings and the weeds were studied,and the motion track of the weeding wheel was analyzed to obtain the structural parameters of the weeding wheel.Then,the structural model of the weeding wheel was designed.The interaction process between the weeding wheel and soil in the paddy fields was simulated and analyzed based on the discrete element method,so as to investigate the working resistance change tendency of the weeding wheel and the orderliness of the soil disturbances.An orthogonal test was designed in this study,with three factors:the hoeing depth,the rotation rate of the weeding wheel,and the forward speed of the device.The influences of different operation parameters of the weeding machine on the weeding torque and soil disturbance speed were obtained based on a variance analysis of the test results.A multi-index comprehensive weighted scoring method was used to evaluate the simulation results.A soil bin test was conducted to verify the simulation results.Field experiments were carried out to test the working performance of the weeding machine.The comprehensive scoring results indicated that a better working performance of the weeding operation could be obtained when the hoeing depth was 50 mm,the rotation rate of the weeding wheel was 240 r/min,and the forward speed was 0.6 m/s.The results of the soil bin test were consistent with the simulation results.The results of the field experiment revealed that the weeding machine met the requirements for organic rice weeding.These results can provide a reference for the design of weeding machines for paddy fields.
