Rice dry-direct-seeding technology is a time-saving,cost-saving and efficient rice cultivation technique that increases the efficiency of seeding.In order to implement the specialization,light simplicity and scale of ...Rice dry-direct-seeding technology is a time-saving,cost-saving and efficient rice cultivation technique that increases the efficiency of seeding.In order to implement the specialization,light simplicity and scale of rice production,improve the level of mechanization of the whole rice production process,and solve the problems of uneven seed furrows,uneven number of seeds sown,shallow mulching and uncompact repression that occur during the promotion and application of dry-direct-seeding for rice in the cold region of northeast China.In this paper,a planting unit for rice dry-direct-seeding planter is designed.The working principles and structural parameters of the furrow opening components,the seeding apparatus and the soil covering-pressing device are described.The mechanical model of the key components of the seeding unit was established,and the forward speed,roller diameter and compacting strength were selected as the test factors.A three-factor,five-level quadratic rotation orthogonal combination test was conducted with the seed breakage rate,seeding depth qualification rate,seeding uniformity coefficient of variation and hole grain count qualification rate as the evaluation indexes.Field performance test and test results show that:at a forward speed of 4 km/h,a roller diameter of 427 mm and a compacting strength of 48.45 kPa,the seed breakage rate was 1.31%,the sowing depth qualification rate was 9.95%,the coefficient of variation of sowing uniformity was 3.75%and the number of holes was 86.75%.This accords with the agronomic requirements of dry-directseeding for rice and implements a combination of superior agronomy and modern farm machinery.展开更多
Since the low seed filling speed of mechanical seed metering devices reduces the low qualified rate of seed spacing during high-speed practices,it is significant to design agitated seed metering devices with horizonta...Since the low seed filling speed of mechanical seed metering devices reduces the low qualified rate of seed spacing during high-speed practices,it is significant to design agitated seed metering devices with horizontal seed filling that are suitable for high-speed practices.The combination of horizontal seed filling and agitated seed filling can accelerate the seed filling of mechanical seed metering devices,and improve the qualified rate of seed spacing during high-speed practices.In this study,theoretical analysis,discrete element method-based simulation and indoor bench test verification were conducted to investigate how key parameters of the agitated seed metering device with horizontal seed filling(angles,installation position and number of agitating plates,diameters of convex spoons)would affect the characteristics of soybean seed movement,seed number and seeding performance(qualified index,multiple index,missing seeding index)under different working speeds.Computer-based simulation,test design and regression analysis were combined to analyze the population moving rules and optimize the design parameters of seed metering devices.Based on the test scheme as designed,simulations were conducted on Fluent EDEM,and the optimal angle of the agitating plates was determined by analyzing the population migrating rules.Regression equations were established through the regression of test results,and used to find out the optimal design parameters(diameter of convex spoon,positions and number of agitating plates)of seed metering devices.Then the optimal parameter combination among different working conditions was determined that the angle,position and number of agitating plates were 30°,24.4 mm,and 13,respectively,and the diameter of convex spoon was 11.0 mm.With the optimal parameter combination and at the seeding speed of 12 km/h,the qualified index,multiple index and missing seeding index were 93.1%,2.1%and 4.8%,respectively.Under high-speed practices,the new seed metering device was not significantly different from the pneumatic seed metering device,but significantly outperformed the mechanical seed metering device.展开更多
Given the technical problems of low maize stubble breaking efficiency,large cutting torque and high power consumption faced during springtime no-till planting in Northeast China,we designed a high-performance coupling...Given the technical problems of low maize stubble breaking efficiency,large cutting torque and high power consumption faced during springtime no-till planting in Northeast China,we designed a high-performance coupling bionic stubble cutting device capable by integrating the structure(multi-segment and serrate)and cutting mode(isokinetic and symmetrical)of locust mouthparts.Methods of bionic construction,mechanism design,theoretical analysis,parameter optimization,Arduino systems and intelligent control were combined to design a planetary gear mechanism and an intelligent speed control system.In particular,the bionic cutting blade could reconstruct the multi-segment and serrate structure of locust mouthparts,while the planetary gear mechanism and the intelligent speed control system jointly comprised the bionic drive system,which could simulate the isokinetic and symmetrical cutting mode,thereby bionically coupling morphological structures and movement patterns.Analysis of comparative tests showed the coupling bionic cutting device could reduce the cutting torque by 26.6%-31.6%and the power consumption by 21.9%-26.1%.This work confirmed that coupling bionic method can significantly improve the stubble cutting efficiency,which was a valuable contribution to the design of stubble cutting device for no-till planter.展开更多
In cold and arid regions,soil moisture content and accumulated temperature were seriously insufficient during spring sowing,which made it difficult for soybean seedling to emerge.Based on the principle of earthworm op...In cold and arid regions,soil moisture content and accumulated temperature were seriously insufficient during spring sowing,which made it difficult for soybean seedling to emerge.Based on the principle of earthworm optimization and improvement of soil structure,this study innovatively designed a biomimetic earthworm dynamic soil looser through bionic design and theoretical calculation.By highly reducing the movement path and mode of earthworm in the soil,the mechanism could improve the soil temperature(ST)and soil moisture content(SMC),and thus greatly improve the soybean emergence rate(SER).In this study,the effects of biomimetic earthworm dynamic soil looser and its design parameters on soil temperature(ST),soil moisture content(SMC)and soybean emergence rate(SER)were investigated by two-factor test,analysis of variance(ANOVA)and Least significant Difference(LSD).Regression analysis was used to establish the mathematical model between design parameters and soybean emergence rate.MATLAB software was used to optimize the model,and the optimal design parameter combination was obtained.The contrast experiments showed that the biomimetic earthworm dynamic soil looser could construct the soil structure more suitable for the cold and arid regions.Compared with rotary blade(RB)and notched disc harrow(DH),biomimetic earthworm dynamic soil looser could increase soil moisture content by 41.30%and 27.50%,respectively.Compared with the notched disc harrow,the soil temperature could be increased by 7.97%.There was no significant difference between the effect of rotary blade on soil temperature(p>0.05).The soybean emergence rate was increased by 25.40%and 20.70%,respectively,compared with that of notched disc harrow and rotary blade.展开更多
In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,i...In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,in this study,bionic mole forelimb intelligent row cleaners comprising of a cleaning device and a depth intelligent control system were designed.Via theoretical analysis,computer-based simulation,and test optimized design,the mechanism of bionic cleaners that possessed the forelimb motion morphology and the front claw toe structural morphology of moles was studied,the effects of structural parameters of bionic cleaners on the cleaning quality were clarified.Based on a pressure sensor,a depth intelligent control system was designed,which enhanced the depth stability of the cleaning devices.The types of bionic cleaners were identified by simulation on EDEM software.Then regression equations between different parameters and operation evaluation indices were established,and the optimal parameter combination was identified on Design-Expert software with a rotation radius of 150 mm and a motion deflection angle of 15.8°,at which the cleaning rate was 91.3%.Field tests under the optimal parameter combination showed that bionic cleaners outperformed normal planar cleaners,and the depth intelligent control system could efficiently improve the performance of the row cleaners.The straw cleaning rate of the bionic mole forelimb intelligent row cleaners under total straw mulching fields was 90.9%,which was 21.3%higher than that of normal cleaners,and the ground surfaces after operation satisfied the agricultural requirements of maize no-tillage sowing.展开更多
The insufficient accumulated temperature of the plow layer during spring tillage in Northeast China severely restricts soybean root growth and whole-plant development.High regional soil viscosity further complicates t...The insufficient accumulated temperature of the plow layer during spring tillage in Northeast China severely restricts soybean root growth and whole-plant development.High regional soil viscosity further complicates tilling-sowing.In order to seek a solution to these problems,field comparative tests were conducted to investigate the effects of shallow-loosening(SL)and reshaping ridge(RR)on soil temperature and soybean root growth.Compared with conventional tillage(CT),SL and RR significantly increased the soil temperatures within 0-25 cm(p<0.05)and 0-15 cm(p<0.05),respectively.In particular,higher soil temperature within 15-25 cm was established after SL than after RR(p<0.05).Additionally,SL promoted substantially more vigorous soybean development(seedling height)than RR(p<0.05),which in turn led to a significant outperformance over CT(p<0.05).Further,bionics,reverse engineering,and curve fitting were combined to design a hare claw toe bionic shallow-loosening shovel and a pangolin scale bionic ridging shovel with anti-drag functions.Field verification tests confirmed that these two bionic tillage devices outperformed the conventional tillage device in reducing tractive drag by 13%-19%.Based on the results of these tests,a 2BGD-6(110)bionic wide-ridge soybean tilling-sowing machine was designed,which was capable of shallow-loosening,reshaping ridge and sowing.The new machine significantly reduced the tractive drag,efficiently loosened the soil,increased soil temperature,and accelerated soybean root growth.This study can provide a theoretical and practical reference for soybean production in Northeast China.展开更多
In order to improve soil fertility and fertilizer utilization,a subsoiling variable rate fertilization machine based on conservation tillage and precision agriculture was designed and tested.The relationship between s...In order to improve soil fertility and fertilizer utilization,a subsoiling variable rate fertilization machine based on conservation tillage and precision agriculture was designed and tested.The relationship between suspension parameters and penetrating distance was analyzed,and a matching model between fertilizing quantity and penetrating distance was established.The variable rate fertilization control machine was developed based on an Advantech PCM-9363 industrial control mainboard.The machine operates under two patterns:DGPS-based positioning and straight-line path positioning based on a planar coordinate system.This machine can perform on-demand fertilization according to the spatial differences in soil nutrients and the prescription maps pre-set before the operation.Field experiments showed the machine has a subsoiling stability of 92.5%,a soil breaking rate of 61.1%,a maximum positioning relative error of 2.68%and a maximum variable rate fertilization error of 3.89%.The subsoiling performance and variable rate fertilization indices of this machine satisfy the requirements of GB/T24675.2-2009.The tested indices meet the national and industrial standards and satisfy the design requirements.The findings of the research can be used as the structural design of the subsoiling variable rate fertilization machine.展开更多
Under the conditions of straw returning operation,there are three major technical bottlenecks in the Phaeozem region of northeast China,namely low stubble breaking rate,poor tillage depth consistency,and high fuel con...Under the conditions of straw returning operation,there are three major technical bottlenecks in the Phaeozem region of northeast China,namely low stubble breaking rate,poor tillage depth consistency,and high fuel consumption.In this research,a bionic stubble-deep loosening combined tillage machine(BSD)was designed through bionic prototype analysis,coupled bionic analysis,coupled bionic design,theoretical analysis and application of intelligent control techniques.It consists of a bionic stubble breaking device and a bionic self-excited vibratory deep loosening device.Based on the unique biting pattern of locust mouthparts on maize rootstocks,the bionic stubble breaking device adopted a new multi-segment serrated bionic structure and a symmetrical rotational motion,which could significantly increase the stubble breaking rate(p<0.05)and reduce the resistance to stubble breaking operations(p<0.05).Based on the unique biology of the hare’s paws,toes and nails,the bionic self-excited vibration deep loosening device adopted a new series-parallel composite bionic elastic system and an intelligent tilling depth control system with a fuzzy algorithm,which significantly improved the tilling depth consistency(p<0.05).The operational performance of the BSD was verified at different operating speeds through comparative experiments and reveals the mechanism of its excellent performance through theoretical analysis.The final experiment results showed that,at the same operating speed,the BSD improved the stubble breaking rate by 9.62%and 10.67%,reduced the stubble breaking torque by 28 N·m and 33 N·m,reduced the tillage depth coefficient of variation by 12.73%and 13.48%,and reduced the specific fuel consumption by 36 g/km·h and 40 g/km·h compared to the two most common models.The operating performance of the three kinds of machines will decrease with the increase of operating speed,and the BSD has the least decrease.展开更多
Structural and functional biomimicking of the active site of [NiFe]-hydrogenases can provide helpful hints for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptak...Structural and functional biomimicking of the active site of [NiFe]-hydrogenases can provide helpful hints for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptake.Treatment of dianion [Ni(phma)]2-[H4 phma=N,N’-1,2-phenylenebis(2-mercaptoacetamide)] with [NiCl2(dppp)](dppp=bis(diphenylphosphino)propane) yielded a dinickel product[Ni(phma)(μ-S,S’)Ni(dppp)](1) as the model complex relevant to the active site of [NiFe]-H2 ases.The structure of complex 1 has been characterized by single-crystal X-ray analysis.From cyclic voltammetry and controlled potential electrolysis studies,complex 1 was found to be a moderate electrocatalyst for the H2-evoluting reaction using ClCH2COOH as the proton source.展开更多
An online detection device that used the capacitance method to detect the moisture content of rice in a combine harvester was designed and found a low detection accuracy because of the high impurity content of the sam...An online detection device that used the capacitance method to detect the moisture content of rice in a combine harvester was designed and found a low detection accuracy because of the high impurity content of the samples.To solve this problem,a screening and impurity removal device was designed in this study,and the structural parameter range of the screw conveyor was the focus of the design.To determine the best structural parameters and operating parameters of the device,models of rice grains and short stems were established by the discrete element method.The Discrete Element Method(DEM)simulation test was carried out according to the Box-Behnken response surface method.When the rotating speed was 300 r/min,the diameter of spiral blade was 146 mm,the pitch was 80 mm,the diameter of rotating shaft was 30.6 mm,and the minimum impurity content was 0.27%.The density distributions and movement characteristics of the rice grains and short stems in the optimized screening and impurity removal device were studied.An experiment was carried out to compare data for the moisture content of rice measured by the online moisture content detection device before and after the installation of the screening and impurity removal device and the results of the 105°C drying method.The results showed that the impurity content of rice ranged from 0.26%to 0.37%,and the maximum effective screening rate was 90.99%after screening.The screening and impurity removal device significantly reduced the error in the moisture content measured by the online detection device,the error range was 0.12%-2.55%.This study provides a method for accurate online detection of moisture content and provides a reference for the design and simulation of related screening devices.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52075215 and 52275250 and 52105300)Key Research and Development Program of Changchun,China(Grant No.21ZGN22)and the Science and Technology Research Project of Jilin Provincial Education Department(No.JJKH20221021KJ).
文摘Rice dry-direct-seeding technology is a time-saving,cost-saving and efficient rice cultivation technique that increases the efficiency of seeding.In order to implement the specialization,light simplicity and scale of rice production,improve the level of mechanization of the whole rice production process,and solve the problems of uneven seed furrows,uneven number of seeds sown,shallow mulching and uncompact repression that occur during the promotion and application of dry-direct-seeding for rice in the cold region of northeast China.In this paper,a planting unit for rice dry-direct-seeding planter is designed.The working principles and structural parameters of the furrow opening components,the seeding apparatus and the soil covering-pressing device are described.The mechanical model of the key components of the seeding unit was established,and the forward speed,roller diameter and compacting strength were selected as the test factors.A three-factor,five-level quadratic rotation orthogonal combination test was conducted with the seed breakage rate,seeding depth qualification rate,seeding uniformity coefficient of variation and hole grain count qualification rate as the evaluation indexes.Field performance test and test results show that:at a forward speed of 4 km/h,a roller diameter of 427 mm and a compacting strength of 48.45 kPa,the seed breakage rate was 1.31%,the sowing depth qualification rate was 9.95%,the coefficient of variation of sowing uniformity was 3.75%and the number of holes was 86.75%.This accords with the agronomic requirements of dry-directseeding for rice and implements a combination of superior agronomy and modern farm machinery.
基金supported by the 13th Five-Year Plan for National Science and Technology(Grant No.2016YFD0700302)National Natural Science Foundation of China(51705194)(JJKH20170811KJ).
文摘Since the low seed filling speed of mechanical seed metering devices reduces the low qualified rate of seed spacing during high-speed practices,it is significant to design agitated seed metering devices with horizontal seed filling that are suitable for high-speed practices.The combination of horizontal seed filling and agitated seed filling can accelerate the seed filling of mechanical seed metering devices,and improve the qualified rate of seed spacing during high-speed practices.In this study,theoretical analysis,discrete element method-based simulation and indoor bench test verification were conducted to investigate how key parameters of the agitated seed metering device with horizontal seed filling(angles,installation position and number of agitating plates,diameters of convex spoons)would affect the characteristics of soybean seed movement,seed number and seeding performance(qualified index,multiple index,missing seeding index)under different working speeds.Computer-based simulation,test design and regression analysis were combined to analyze the population moving rules and optimize the design parameters of seed metering devices.Based on the test scheme as designed,simulations were conducted on Fluent EDEM,and the optimal angle of the agitating plates was determined by analyzing the population migrating rules.Regression equations were established through the regression of test results,and used to find out the optimal design parameters(diameter of convex spoon,positions and number of agitating plates)of seed metering devices.Then the optimal parameter combination among different working conditions was determined that the angle,position and number of agitating plates were 30°,24.4 mm,and 13,respectively,and the diameter of convex spoon was 11.0 mm.With the optimal parameter combination and at the seeding speed of 12 km/h,the qualified index,multiple index and missing seeding index were 93.1%,2.1%and 4.8%,respectively.Under high-speed practices,the new seed metering device was not significantly different from the pneumatic seed metering device,but significantly outperformed the mechanical seed metering device.
基金This work was supported by the project of National Key R&D Program of China(No.2018YFA0703300)and the National Natural Science Foundation of China(Grant no.51705194)+1 种基金and Science and Technology Project of Jilin(20190301023NY)and National Natural Science Foundation of Jilin(20180101090JC).
文摘Given the technical problems of low maize stubble breaking efficiency,large cutting torque and high power consumption faced during springtime no-till planting in Northeast China,we designed a high-performance coupling bionic stubble cutting device capable by integrating the structure(multi-segment and serrate)and cutting mode(isokinetic and symmetrical)of locust mouthparts.Methods of bionic construction,mechanism design,theoretical analysis,parameter optimization,Arduino systems and intelligent control were combined to design a planetary gear mechanism and an intelligent speed control system.In particular,the bionic cutting blade could reconstruct the multi-segment and serrate structure of locust mouthparts,while the planetary gear mechanism and the intelligent speed control system jointly comprised the bionic drive system,which could simulate the isokinetic and symmetrical cutting mode,thereby bionically coupling morphological structures and movement patterns.Analysis of comparative tests showed the coupling bionic cutting device could reduce the cutting torque by 26.6%-31.6%and the power consumption by 21.9%-26.1%.This work confirmed that coupling bionic method can significantly improve the stubble cutting efficiency,which was a valuable contribution to the design of stubble cutting device for no-till planter.
基金The authors acknowledge that the research was financially supported by the Natural Science Foundation of China(Grant No.52075215)National Key Research and Development Program of China(Grant No.2017YFD0700701)+1 种基金Science and Technology Development Plan Project of Jilin Province(Grant No.20190301023NY and 20190701055GH and 20200404008YY)China Postdoctoral Science Foundation(Grant No.2020M67085).
文摘In cold and arid regions,soil moisture content and accumulated temperature were seriously insufficient during spring sowing,which made it difficult for soybean seedling to emerge.Based on the principle of earthworm optimization and improvement of soil structure,this study innovatively designed a biomimetic earthworm dynamic soil looser through bionic design and theoretical calculation.By highly reducing the movement path and mode of earthworm in the soil,the mechanism could improve the soil temperature(ST)and soil moisture content(SMC),and thus greatly improve the soybean emergence rate(SER).In this study,the effects of biomimetic earthworm dynamic soil looser and its design parameters on soil temperature(ST),soil moisture content(SMC)and soybean emergence rate(SER)were investigated by two-factor test,analysis of variance(ANOVA)and Least significant Difference(LSD).Regression analysis was used to establish the mathematical model between design parameters and soybean emergence rate.MATLAB software was used to optimize the model,and the optimal design parameter combination was obtained.The contrast experiments showed that the biomimetic earthworm dynamic soil looser could construct the soil structure more suitable for the cold and arid regions.Compared with rotary blade(RB)and notched disc harrow(DH),biomimetic earthworm dynamic soil looser could increase soil moisture content by 41.30%and 27.50%,respectively.Compared with the notched disc harrow,the soil temperature could be increased by 7.97%.There was no significant difference between the effect of rotary blade on soil temperature(p>0.05).The soybean emergence rate was increased by 25.40%and 20.70%,respectively,compared with that of notched disc harrow and rotary blade.
基金This work was financially supported by the National Key R&D Plan project(Grant No.2016YFD070030201)the Jilin Science and Technology Development Plan(20160309001NY)。
文摘In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,in this study,bionic mole forelimb intelligent row cleaners comprising of a cleaning device and a depth intelligent control system were designed.Via theoretical analysis,computer-based simulation,and test optimized design,the mechanism of bionic cleaners that possessed the forelimb motion morphology and the front claw toe structural morphology of moles was studied,the effects of structural parameters of bionic cleaners on the cleaning quality were clarified.Based on a pressure sensor,a depth intelligent control system was designed,which enhanced the depth stability of the cleaning devices.The types of bionic cleaners were identified by simulation on EDEM software.Then regression equations between different parameters and operation evaluation indices were established,and the optimal parameter combination was identified on Design-Expert software with a rotation radius of 150 mm and a motion deflection angle of 15.8°,at which the cleaning rate was 91.3%.Field tests under the optimal parameter combination showed that bionic cleaners outperformed normal planar cleaners,and the depth intelligent control system could efficiently improve the performance of the row cleaners.The straw cleaning rate of the bionic mole forelimb intelligent row cleaners under total straw mulching fields was 90.9%,which was 21.3%higher than that of normal cleaners,and the ground surfaces after operation satisfied the agricultural requirements of maize no-tillage sowing.
基金We acknowledge that this work was financially supported by Key Project Supported by the 13th Five-Year Plan for National Science and Technology(2016YFD0700302)National Natural Science Foundation of China(51705194)technology development project of Jilin province(20160309001NY,20190301023NY).
文摘The insufficient accumulated temperature of the plow layer during spring tillage in Northeast China severely restricts soybean root growth and whole-plant development.High regional soil viscosity further complicates tilling-sowing.In order to seek a solution to these problems,field comparative tests were conducted to investigate the effects of shallow-loosening(SL)and reshaping ridge(RR)on soil temperature and soybean root growth.Compared with conventional tillage(CT),SL and RR significantly increased the soil temperatures within 0-25 cm(p<0.05)and 0-15 cm(p<0.05),respectively.In particular,higher soil temperature within 15-25 cm was established after SL than after RR(p<0.05).Additionally,SL promoted substantially more vigorous soybean development(seedling height)than RR(p<0.05),which in turn led to a significant outperformance over CT(p<0.05).Further,bionics,reverse engineering,and curve fitting were combined to design a hare claw toe bionic shallow-loosening shovel and a pangolin scale bionic ridging shovel with anti-drag functions.Field verification tests confirmed that these two bionic tillage devices outperformed the conventional tillage device in reducing tractive drag by 13%-19%.Based on the results of these tests,a 2BGD-6(110)bionic wide-ridge soybean tilling-sowing machine was designed,which was capable of shallow-loosening,reshaping ridge and sowing.The new machine significantly reduced the tractive drag,efficiently loosened the soil,increased soil temperature,and accelerated soybean root growth.This study can provide a theoretical and practical reference for soybean production in Northeast China.
基金The authors acknowledge that this work was financially supported by the National Natural Science Foundation of China(No.31401284)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2014BAD06B03).
文摘In order to improve soil fertility and fertilizer utilization,a subsoiling variable rate fertilization machine based on conservation tillage and precision agriculture was designed and tested.The relationship between suspension parameters and penetrating distance was analyzed,and a matching model between fertilizing quantity and penetrating distance was established.The variable rate fertilization control machine was developed based on an Advantech PCM-9363 industrial control mainboard.The machine operates under two patterns:DGPS-based positioning and straight-line path positioning based on a planar coordinate system.This machine can perform on-demand fertilization according to the spatial differences in soil nutrients and the prescription maps pre-set before the operation.Field experiments showed the machine has a subsoiling stability of 92.5%,a soil breaking rate of 61.1%,a maximum positioning relative error of 2.68%and a maximum variable rate fertilization error of 3.89%.The subsoiling performance and variable rate fertilization indices of this machine satisfy the requirements of GB/T24675.2-2009.The tested indices meet the national and industrial standards and satisfy the design requirements.The findings of the research can be used as the structural design of the subsoiling variable rate fertilization machine.
基金The authors acknowledge that the research was financially supported by the National Key Research and Development Project of China(Grant No.2017YFD0700701)the Natural Science Foundation of China(Grant No.52075215)+1 种基金the Science and Technology Development Plan Project of Jilin Province(Grant No.20190301023NY,20190701055GH and 20200404008YY)China Postdoctoral Science Foundation(Grant No.2020M67085).
文摘Under the conditions of straw returning operation,there are three major technical bottlenecks in the Phaeozem region of northeast China,namely low stubble breaking rate,poor tillage depth consistency,and high fuel consumption.In this research,a bionic stubble-deep loosening combined tillage machine(BSD)was designed through bionic prototype analysis,coupled bionic analysis,coupled bionic design,theoretical analysis and application of intelligent control techniques.It consists of a bionic stubble breaking device and a bionic self-excited vibratory deep loosening device.Based on the unique biting pattern of locust mouthparts on maize rootstocks,the bionic stubble breaking device adopted a new multi-segment serrated bionic structure and a symmetrical rotational motion,which could significantly increase the stubble breaking rate(p<0.05)and reduce the resistance to stubble breaking operations(p<0.05).Based on the unique biology of the hare’s paws,toes and nails,the bionic self-excited vibration deep loosening device adopted a new series-parallel composite bionic elastic system and an intelligent tilling depth control system with a fuzzy algorithm,which significantly improved the tilling depth consistency(p<0.05).The operational performance of the BSD was verified at different operating speeds through comparative experiments and reveals the mechanism of its excellent performance through theoretical analysis.The final experiment results showed that,at the same operating speed,the BSD improved the stubble breaking rate by 9.62%and 10.67%,reduced the stubble breaking torque by 28 N·m and 33 N·m,reduced the tillage depth coefficient of variation by 12.73%and 13.48%,and reduced the specific fuel consumption by 36 g/km·h and 40 g/km·h compared to the two most common models.The operating performance of the three kinds of machines will decrease with the increase of operating speed,and the BSD has the least decrease.
基金supported by National Natural Science Foundation of China(Nos.21773184,21671158 and 21601164)Natural Science Foundation of Henan(No.162300410052)Key Science and Technology Project of Henan(No.172102310137)。
文摘Structural and functional biomimicking of the active site of [NiFe]-hydrogenases can provide helpful hints for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptake.Treatment of dianion [Ni(phma)]2-[H4 phma=N,N’-1,2-phenylenebis(2-mercaptoacetamide)] with [NiCl2(dppp)](dppp=bis(diphenylphosphino)propane) yielded a dinickel product[Ni(phma)(μ-S,S’)Ni(dppp)](1) as the model complex relevant to the active site of [NiFe]-H2 ases.The structure of complex 1 has been characterized by single-crystal X-ray analysis.From cyclic voltammetry and controlled potential electrolysis studies,complex 1 was found to be a moderate electrocatalyst for the H2-evoluting reaction using ClCH2COOH as the proton source.
基金supported by the Program on Industrial Technology System of National Rice(CN)(CARS-01-48).
文摘An online detection device that used the capacitance method to detect the moisture content of rice in a combine harvester was designed and found a low detection accuracy because of the high impurity content of the samples.To solve this problem,a screening and impurity removal device was designed in this study,and the structural parameter range of the screw conveyor was the focus of the design.To determine the best structural parameters and operating parameters of the device,models of rice grains and short stems were established by the discrete element method.The Discrete Element Method(DEM)simulation test was carried out according to the Box-Behnken response surface method.When the rotating speed was 300 r/min,the diameter of spiral blade was 146 mm,the pitch was 80 mm,the diameter of rotating shaft was 30.6 mm,and the minimum impurity content was 0.27%.The density distributions and movement characteristics of the rice grains and short stems in the optimized screening and impurity removal device were studied.An experiment was carried out to compare data for the moisture content of rice measured by the online moisture content detection device before and after the installation of the screening and impurity removal device and the results of the 105°C drying method.The results showed that the impurity content of rice ranged from 0.26%to 0.37%,and the maximum effective screening rate was 90.99%after screening.The screening and impurity removal device significantly reduced the error in the moisture content measured by the online detection device,the error range was 0.12%-2.55%.This study provides a method for accurate online detection of moisture content and provides a reference for the design and simulation of related screening devices.
