Lithium batteries (LBs) have become increasingly important energy storage systems in our daily life. However, their practical applications are still severely plagued by the safety issues from liquid electrolyte, espec...Lithium batteries (LBs) have become increasingly important energy storage systems in our daily life. However, their practical applications are still severely plagued by the safety issues from liquid electrolyte, especially when the batteries are exposed to mechanical, thermal, or electrical abuse conditions. Gel polymer electrolytes (GPEs) are being considered as an effective solution to replace currently available organic liquid electrolyte for building safer LBs. This review provides recent advancements in GPEs applied for high-performance LBs. On the one hand, from the environmental and economic point of view, the skeletons of GPEs changed from traditional polymer to renewable and degradable polymer. On the other hand, in addition to being as a component with good electrochemical and physical characterizations, the GPEs also need to provide some functions for addressing the concerns of lithium (Li) dendrites, unstable cathode electrolyte interface, dissolution and migration of transition metal ions,"shuttle effect" of polysulfides, and so on. Finally, to synchronously meet the challenges from the advanced cathode and Li metal anode, the bio-based GPEs with multi-functionality are proposed to develop high-energy/powerdensity batteries in the future.展开更多
A breakthrough in advancing power density and stability of carbon-based supercapacitors is trapped by inefficient pore structures of electrode materials.Herein,an ultramicroporous carbon with ultrahigh integrated capa...A breakthrough in advancing power density and stability of carbon-based supercapacitors is trapped by inefficient pore structures of electrode materials.Herein,an ultramicroporous carbon with ultrahigh integrated capacitance fabricated via one-step carbonization/activation of dense bacterial cellulose(BC)precursor followed by nitrogen/sulfur dual doping is reported.The microporous carbon possesses highly concentrated micropores(~2 nm)and a considerable amount of sub-micropores(<1 nm).The unique porous structure provides high specific surface area(1554 m^2 g^-1)and packing density(1.18 g cm^-3).The synergistic effects from the particular porous structure and optimal doping effectively enhance ion storage and ion/electron transport.As a result,the remarkable specific capacitances,including ultrahigh gravimetric and volumetric capacitances(430 F g^-1 and 507 F cm^-3 at 0.5 A g^-1),and excellent cycling and rate stability even at a high current density of 10 A g^-1(327 F g^-1 and 385 F cm^-3)are realized.Via compositing the porous carbon and BC skeleton,a robust all-solid-state cellulose-based supercapacitor presents super high areal energy density(~0.77 mWh cm^-2),volumetric energy density(~17.8 W L^-1),and excellent cyclic stability.展开更多
Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather applications.In this paper,the energetic electron detection package(EEDP)de...Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather applications.In this paper,the energetic electron detection package(EEDP)deployed on three Chinese navigation satellites in medium Earth orbit(MEO)is reviewed.The instrument was developed by the space science payload team led by Peking University.The EEDP includes a pinhole medium-energy electron spectrometer(MES),a high-energy electron detector(HED)based onΔE-E telescope technology,and a deep dielectric charging monitor(DDCM).The MES measures the energy spectra of 50−600 keV electrons from nine directions with a 180°×30°field of view(FOV).The HED measures the energy spectrum of 0.5−3.0 MeV electrons from one direction with a 30°cone-angle FOV.The ground test and calibration results indicate that these three sensors exhibit excellent performance.Preliminary observations show that the electron spectra measured by the MES and HED are in good agreement with the results from the magnetic electron-ion spectrometer(MagEIS)of the Van Allen Probes spacecraft,with an average relative deviation of 27.3%for the energy spectra.The charging currents and voltages measured by the DDCM during storms are consistent with the highenergy electron observations of the HED,demonstrating the effectiveness of the DDCM.The observations of the EEDP on board the three MEO satellites can provide important support for theoretical research on the radiation belts and the applications related to space weather.展开更多
Layered lanthanum silver antimonide LaAgSb_(2)exhibits both charge density wave(CDW)order and Dirac-cone-like band structure at ambient pressure.Here,we systematically investigate the pressure evolution of structural ...Layered lanthanum silver antimonide LaAgSb_(2)exhibits both charge density wave(CDW)order and Dirac-cone-like band structure at ambient pressure.Here,we systematically investigate the pressure evolution of structural and electronic properties of LaAgSb_(2)single crystal.We show that the CDW order is destabilized under compression,as evidenced by the gradual suppression of magnetoresistance.At P_(C)~22 GPa,synchrotron x-ray diffraction and Raman scattering measurements reveal a structural modification at room-temperature.Meanwhile,the sign change of the Hall coefficient is observed at 5 K.Our results demonstrate the tunability of CDW order in the pressurized LaAgSb_(2)single crystal,which can be helpful for its potential applications in the next-generation devices.展开更多
The present-day Global Positioning System(GPS)velocity field shows that the Indian Plate is not a complete rigid block,as its northeastern corner has been torn off and clockwise rotating relative to the main part.With...The present-day Global Positioning System(GPS)velocity field shows that the Indian Plate is not a complete rigid block,as its northeastern corner has been torn off and clockwise rotating relative to the main part.With the updated GPS velocity data,the Euler vector of the northeastern corner of the Indian Plate relative to the stable main plate is deduced as(89.566±0.06°E,26.131±0.05°N,1.34±0.11°/Myr).The peak area of the present-day crustal deformation is located in the Chayu deformation belt with the compressional dilation strain rate over 160 nanostrain/yr.However,the Namche-Barwa Syntaxis with the massive crustal thickening and intense surface erosion is generally considered to be the previous locus of the strongest compressional stress in the Eastern Himalayan Syntaxis over long geological timescales.Thus,there is a discrepancy between the previous and present-day crustal deformation peak areas.We argue the migration of the crustal deformation peak area with a total distance of about 120 km and ascribe it to the variation of stress conditions caused by northeast India’s clockwise rotation.展开更多
Aiming at geological disaster monitoring and prevention work, a real-time monitoring and early warning system is proposed for low-power consumption of landslides to meet the needs of landslide monitoring in remote mou...Aiming at geological disaster monitoring and prevention work, a real-time monitoring and early warning system is proposed for low-power consumption of landslides to meet the needs of landslide monitoring in remote mountainous areas. The inclination angle of the mountain body was detected by a mechanical inclination sensor, and a plurality of inclination sensors were placed on each landslide body to form an array distribution. The landslide body was stereoscopically monitored. Each mesh node had a different node address, and different inclination thresholds were set in advance. When the sensor detection value reached the threshold, an alarm message was sent to the system main control end, and the main control end generated an audible and visual alarm, and an alarm message was sent at the same time. Compared with the current landslide warning system on the market, the system achieves expected results and its power consumption is extremely low. The sensor terminal of the mountain monitoring is powered by dry battery and can work for 6 years in the field without external power supply. It avoids the damages made by weather, livestock and human, and has broad application prospects.展开更多
van der Waals(vdW)semiconductors have gained significant attention due to their unique physical properties and promising applications,which are embedded within distinct crystallographic symmetries.Here,we report a pre...van der Waals(vdW)semiconductors have gained significant attention due to their unique physical properties and promising applications,which are embedded within distinct crystallographic symmetries.Here,we report a pressure-induced crystallineamorphization-recrystallization transition under compression in binary vdW semiconductor SiP.Upon compression to 52 GPa,bulk SiP undergoes a consecutive phase transition from pristine crystalline to amorphous phase,ultimately to recrystallized phase.By employing synchrotron X-ray diffraction experiments in conjunction with high-pressure crystal structure searching techniques,we reveal that the recrystallized Si P hosts a tetragonal structure(space group I4mm)and further transforms partially into a cubic phase(space group Fm3m).Consistently,electrical transport and alternating-current magnetic susceptibility measurements indicate the presence of three superconducting phases,which are embedded in separate crystallographic symmetries—the amorphous,tetragonal,and cubic structures.Furthermore,a high superconducting transition temperature of 12.3 K is observed in its recovered tetragonal phase during decompression.Our findings uncover a novel phase evolution path and elucidate a pressure-engineered structure-property relationship in vdW semiconductor SiP.These results not only offer a new platform to explore the transformation between different structures and functionalities,but also provide new opportunities for the design and exploration of advanced devices based on vdW materials.展开更多
Along with the rapid development of flexible and wearable electronic devices,there have been a strong demand for flexible power sources,which has in turn triggered considerable efforts on the research and development ...Along with the rapid development of flexible and wearable electronic devices,there have been a strong demand for flexible power sources,which has in turn triggered considerable efforts on the research and development of flexible batteries.An ideal flexible battery would have not only just high electrochemical performance but also excellent mechanical deformabilities.Therefore,battery constituent components,chemistry systems,device configurations,and practical applications are all pivotal aspects that should be thoroughly considered.Herein,we systematically and comprehensively review the fundamentals and recent progresses of flexible batteries in terms of these important aspects.Specifically,we first discuss the requirements for constituent components,including the current collector,electrolyte,and separator,in flexible batteries.We then elucidate battery chemistry systems that have been studied for various flexible batteries,including lithium-ion batteries,non-lithium-ion batteries,and high-energy metal batteries.This is followed by discussions on the device configurations for flexible batteries,including onedimensional fiber-shaped,two-dimensional film-shaped,and three-dimensional structural batteries.Finally,we summarize recent efforts in exploring practical applications for flexible batteries.Current challenges and future opportunities for the research and development of flexible batteries are also discussed.展开更多
Natural bone is a composite tissue made of organic and inorganic components,showing piezoelectricity.Whitlockite(WH),which is a natural magnesium-containing calcium phosphate,has attracted great attention in bone form...Natural bone is a composite tissue made of organic and inorganic components,showing piezoelectricity.Whitlockite(WH),which is a natural magnesium-containing calcium phosphate,has attracted great attention in bone formation recently due to its unique piezoelectric property after sintering treatment and sustained release of magnesium ion(Mg^(2+)).Herein,a composite scaffold(denoted as PWH scaffold)composed of piezoelectric WH(PWH)and poly(ε-caprolactone)(PCL)was 3D printed to meet the physiological demands for the regeneration of neuro-vascularized bone tissue,namely,providing endogenous electric field at the defect site.The sustained release of Mg^(2+)from the PWH scaffold,displaying multiple biological activities,and thus exhibits a strong synergistic effect with the piezoelectricity on inhibiting osteoclast activation,promoting the neurogenic,angiogenic,and osteogenic differentiation of bone marrow mesenchymal stromal cells(BMSCs)in vitro.In a rat calvarial defect model,this PWH scaffold is remarkably conducive to efficient neo-bone formation with rich neurogenic and angiogenic expressions.Overall,this study presents the first example of biomimetic piezoelectric scaffold with sustained Mg^(2+)release for promoting the regeneration of neuro-vascularized bone tissue in vivo,which offers new insights for regenerative medicine.展开更多
The irregular shape,varying internal compositions,and uneven distributions of maize seeds can degrade the metering performance of maize seeders.This study investigates the effect of irregular maize on the performance ...The irregular shape,varying internal compositions,and uneven distributions of maize seeds can degrade the metering performance of maize seeders.This study investigates the effect of irregular maize on the performance of a high-filling-rate seed metering device using DEM.The results show that the seed population in the seed box formed large and small cycles of seed transport due to the disturbances caused by the three wheels.The increasing angular speed of the three wheels reduced the rate of seed filling in the seed filling regions by gravity and disturbances.In addition,an analysis of the repose angle formed by the dropped seed indicated that the angular speed of the taking seed wheel has a certain effect.The large angular speed reduced the coefficient of variation of the seed drop location.The repose angle of the horse tooth seed was greater than those of the other.Meanwhile,the irregular maize seed can also reduce the coefficient of variation of the seed drop location.A comparison between the simulation and experiment results indicates the number of metering seed were basically the same.展开更多
[Objectives] This study was conducted to improve the nutritional value of soybean milk, enrich the variety and taste of soybean milk, and find healthy food that is more conducive to people s nutritional needs. [Method...[Objectives] This study was conducted to improve the nutritional value of soybean milk, enrich the variety and taste of soybean milk, and find healthy food that is more conducive to people s nutritional needs. [Methods] Whole soybean milk was prepared by grinding with a grinding wheel at a low concentration (low-concentration grinding) and a stainless steel mill at a high concentration (high-concentration grinding). The sensory, physical and chemical characteristics and anti-nutritional factors of whole soybean milk produced by different grinding methods were studied. [Results] Compared with low-concentration grinding, the protein content in soybean milk prepared by high-concentration grinding increased by 24%, and the dietary fiber content increased by 74.7%. Before and after high-pressure homogenization, the particle size D(4, 3) of soybean milk prepared by low-concentration grinding was 212.1 and 93.59 μm, respectively, and the particle size D(4, 3) of soybean milk prepared by high-concentration grinding was 134.0 and 64.64 μm, respectively. The trypsin inhibitor activity and phytic acid content of soybean milk prepared by high-concentration grinding were significantly lower than those of soybean milk prepared by low-concentration grinding. [Conclusions] This study improves the diet structure of the broad masses of people, strengthens people s physique, and provides a new idea for the implementation and development of China s "Soybean Action Programme".展开更多
基金financial support from the National Natural Science Foundation of China (No. 51873011 and U1664251)the Fundamental Research Fund for the Central Universities (No. JC1504)
文摘Lithium batteries (LBs) have become increasingly important energy storage systems in our daily life. However, their practical applications are still severely plagued by the safety issues from liquid electrolyte, especially when the batteries are exposed to mechanical, thermal, or electrical abuse conditions. Gel polymer electrolytes (GPEs) are being considered as an effective solution to replace currently available organic liquid electrolyte for building safer LBs. This review provides recent advancements in GPEs applied for high-performance LBs. On the one hand, from the environmental and economic point of view, the skeletons of GPEs changed from traditional polymer to renewable and degradable polymer. On the other hand, in addition to being as a component with good electrochemical and physical characterizations, the GPEs also need to provide some functions for addressing the concerns of lithium (Li) dendrites, unstable cathode electrolyte interface, dissolution and migration of transition metal ions,"shuttle effect" of polysulfides, and so on. Finally, to synchronously meet the challenges from the advanced cathode and Li metal anode, the bio-based GPEs with multi-functionality are proposed to develop high-energy/powerdensity batteries in the future.
文摘A breakthrough in advancing power density and stability of carbon-based supercapacitors is trapped by inefficient pore structures of electrode materials.Herein,an ultramicroporous carbon with ultrahigh integrated capacitance fabricated via one-step carbonization/activation of dense bacterial cellulose(BC)precursor followed by nitrogen/sulfur dual doping is reported.The microporous carbon possesses highly concentrated micropores(~2 nm)and a considerable amount of sub-micropores(<1 nm).The unique porous structure provides high specific surface area(1554 m^2 g^-1)and packing density(1.18 g cm^-3).The synergistic effects from the particular porous structure and optimal doping effectively enhance ion storage and ion/electron transport.As a result,the remarkable specific capacitances,including ultrahigh gravimetric and volumetric capacitances(430 F g^-1 and 507 F cm^-3 at 0.5 A g^-1),and excellent cycling and rate stability even at a high current density of 10 A g^-1(327 F g^-1 and 385 F cm^-3)are realized.Via compositing the porous carbon and BC skeleton,a robust all-solid-state cellulose-based supercapacitor presents super high areal energy density(~0.77 mWh cm^-2),volumetric energy density(~17.8 W L^-1),and excellent cyclic stability.
基金supported by the National Natural Science Foundation of China(No.41374167,41421003,41474140)China's National Basic Research and Development Program(No.2012CB825603).
文摘Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather applications.In this paper,the energetic electron detection package(EEDP)deployed on three Chinese navigation satellites in medium Earth orbit(MEO)is reviewed.The instrument was developed by the space science payload team led by Peking University.The EEDP includes a pinhole medium-energy electron spectrometer(MES),a high-energy electron detector(HED)based onΔE-E telescope technology,and a deep dielectric charging monitor(DDCM).The MES measures the energy spectra of 50−600 keV electrons from nine directions with a 180°×30°field of view(FOV).The HED measures the energy spectrum of 0.5−3.0 MeV electrons from one direction with a 30°cone-angle FOV.The ground test and calibration results indicate that these three sensors exhibit excellent performance.Preliminary observations show that the electron spectra measured by the MES and HED are in good agreement with the results from the magnetic electron-ion spectrometer(MagEIS)of the Van Allen Probes spacecraft,with an average relative deviation of 27.3%for the energy spectra.The charging currents and voltages measured by the DDCM during storms are consistent with the highenergy electron observations of the HED,demonstrating the effectiveness of the DDCM.The observations of the EEDP on board the three MEO satellites can provide important support for theoretical research on the radiation belts and the applications related to space weather.
基金the National Key Research and Development Program of China(Grant Nos.2018YFA0305700,2017YFA0403600,and2016YFA0401804)the National Natural Science Foundation of China(Grant Nos.U1632275,U19A2093,U1932152,U1632162,12004004,11874362,11804344,11704387,and 11674325)+4 种基金the Natural Science Foundation of Anhui Province,China(Grant Nos.1908085QA18,2008085QA40,and1808085MA06)the Users with Excellence Project of Hefei Science Center CAS(Grant Nos.2018HSC-UE012,2020HSC-CIP014,2020HSC-UE015,and2021HSC-UE008)the Major Program of Development Foundation of Hefei Center for Physical Science and Technology(Grant No.2018ZYFX002)supported by the High Magnetic Field Laboratory of Anhui Province(Grant No.AHHM-FX-2020-02)supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2020443)。
文摘Layered lanthanum silver antimonide LaAgSb_(2)exhibits both charge density wave(CDW)order and Dirac-cone-like band structure at ambient pressure.Here,we systematically investigate the pressure evolution of structural and electronic properties of LaAgSb_(2)single crystal.We show that the CDW order is destabilized under compression,as evidenced by the gradual suppression of magnetoresistance.At P_(C)~22 GPa,synchrotron x-ray diffraction and Raman scattering measurements reveal a structural modification at room-temperature.Meanwhile,the sign change of the Hall coefficient is observed at 5 K.Our results demonstrate the tunability of CDW order in the pressurized LaAgSb_(2)single crystal,which can be helpful for its potential applications in the next-generation devices.
基金Fundings were provided by the special project for China Earthquake Industry(Grant No.201508024-2)the National Natural Science Foundation of China(Grant No.41490615)the National Natural Science Foundation of China(Grant No.41604078)。
文摘The present-day Global Positioning System(GPS)velocity field shows that the Indian Plate is not a complete rigid block,as its northeastern corner has been torn off and clockwise rotating relative to the main part.With the updated GPS velocity data,the Euler vector of the northeastern corner of the Indian Plate relative to the stable main plate is deduced as(89.566±0.06°E,26.131±0.05°N,1.34±0.11°/Myr).The peak area of the present-day crustal deformation is located in the Chayu deformation belt with the compressional dilation strain rate over 160 nanostrain/yr.However,the Namche-Barwa Syntaxis with the massive crustal thickening and intense surface erosion is generally considered to be the previous locus of the strongest compressional stress in the Eastern Himalayan Syntaxis over long geological timescales.Thus,there is a discrepancy between the previous and present-day crustal deformation peak areas.We argue the migration of the crustal deformation peak area with a total distance of about 120 km and ascribe it to the variation of stress conditions caused by northeast India’s clockwise rotation.
文摘Aiming at geological disaster monitoring and prevention work, a real-time monitoring and early warning system is proposed for low-power consumption of landslides to meet the needs of landslide monitoring in remote mountainous areas. The inclination angle of the mountain body was detected by a mechanical inclination sensor, and a plurality of inclination sensors were placed on each landslide body to form an array distribution. The landslide body was stereoscopically monitored. Each mesh node had a different node address, and different inclination thresholds were set in advance. When the sensor detection value reached the threshold, an alarm message was sent to the system main control end, and the main control end generated an audible and visual alarm, and an alarm message was sent at the same time. Compared with the current landslide warning system on the market, the system achieves expected results and its power consumption is extremely low. The sensor terminal of the mountain monitoring is powered by dry battery and can work for 6 years in the field without external power supply. It avoids the damages made by weather, livestock and human, and has broad application prospects.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406102,and 2022YFA1602603)the National Natural Science Foundation of China(Grant Nos.12374049,12174397,12204420,12204004,12174395,U19A2093,and 12004004)+3 种基金the Natural Science Foundation of Anhui Province(Grant Nos.2308085MA16,and 2308085QA18)the Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures(Grant No.JZHKYPT-2021-08)supported by the Youth Innovation Promotion Association CAS(Grant No.2020443)supported by the High Magnetic Field Laboratory of Anhui Province under Contract No.AHHM-FX-2021-03。
文摘van der Waals(vdW)semiconductors have gained significant attention due to their unique physical properties and promising applications,which are embedded within distinct crystallographic symmetries.Here,we report a pressure-induced crystallineamorphization-recrystallization transition under compression in binary vdW semiconductor SiP.Upon compression to 52 GPa,bulk SiP undergoes a consecutive phase transition from pristine crystalline to amorphous phase,ultimately to recrystallized phase.By employing synchrotron X-ray diffraction experiments in conjunction with high-pressure crystal structure searching techniques,we reveal that the recrystallized Si P hosts a tetragonal structure(space group I4mm)and further transforms partially into a cubic phase(space group Fm3m).Consistently,electrical transport and alternating-current magnetic susceptibility measurements indicate the presence of three superconducting phases,which are embedded in separate crystallographic symmetries—the amorphous,tetragonal,and cubic structures.Furthermore,a high superconducting transition temperature of 12.3 K is observed in its recovered tetragonal phase during decompression.Our findings uncover a novel phase evolution path and elucidate a pressure-engineered structure-property relationship in vdW semiconductor SiP.These results not only offer a new platform to explore the transformation between different structures and functionalities,but also provide new opportunities for the design and exploration of advanced devices based on vdW materials.
基金financial support from The Special Significant Science and Technology Program of Yunnan Province(No.2016HE001-2016HE002).
文摘Along with the rapid development of flexible and wearable electronic devices,there have been a strong demand for flexible power sources,which has in turn triggered considerable efforts on the research and development of flexible batteries.An ideal flexible battery would have not only just high electrochemical performance but also excellent mechanical deformabilities.Therefore,battery constituent components,chemistry systems,device configurations,and practical applications are all pivotal aspects that should be thoroughly considered.Herein,we systematically and comprehensively review the fundamentals and recent progresses of flexible batteries in terms of these important aspects.Specifically,we first discuss the requirements for constituent components,including the current collector,electrolyte,and separator,in flexible batteries.We then elucidate battery chemistry systems that have been studied for various flexible batteries,including lithium-ion batteries,non-lithium-ion batteries,and high-energy metal batteries.This is followed by discussions on the device configurations for flexible batteries,including onedimensional fiber-shaped,two-dimensional film-shaped,and three-dimensional structural batteries.Finally,we summarize recent efforts in exploring practical applications for flexible batteries.Current challenges and future opportunities for the research and development of flexible batteries are also discussed.
基金This work was supported by the National Natural Science Foundation of China(U22A20159,52003161)the Central Universities(buctrc202220),and the SINOPEC project(421029).
文摘Natural bone is a composite tissue made of organic and inorganic components,showing piezoelectricity.Whitlockite(WH),which is a natural magnesium-containing calcium phosphate,has attracted great attention in bone formation recently due to its unique piezoelectric property after sintering treatment and sustained release of magnesium ion(Mg^(2+)).Herein,a composite scaffold(denoted as PWH scaffold)composed of piezoelectric WH(PWH)and poly(ε-caprolactone)(PCL)was 3D printed to meet the physiological demands for the regeneration of neuro-vascularized bone tissue,namely,providing endogenous electric field at the defect site.The sustained release of Mg^(2+)from the PWH scaffold,displaying multiple biological activities,and thus exhibits a strong synergistic effect with the piezoelectricity on inhibiting osteoclast activation,promoting the neurogenic,angiogenic,and osteogenic differentiation of bone marrow mesenchymal stromal cells(BMSCs)in vitro.In a rat calvarial defect model,this PWH scaffold is remarkably conducive to efficient neo-bone formation with rich neurogenic and angiogenic expressions.Overall,this study presents the first example of biomimetic piezoelectric scaffold with sustained Mg^(2+)release for promoting the regeneration of neuro-vascularized bone tissue in vivo,which offers new insights for regenerative medicine.
基金supported by the National Natural Science Foundation of China(Grant No.52065004,52165028)Special Talent of Gansu Agricultural University(Grant No.GAU-KYQD-2020-15,GAU-KYQD-2020-33).
文摘The irregular shape,varying internal compositions,and uneven distributions of maize seeds can degrade the metering performance of maize seeders.This study investigates the effect of irregular maize on the performance of a high-filling-rate seed metering device using DEM.The results show that the seed population in the seed box formed large and small cycles of seed transport due to the disturbances caused by the three wheels.The increasing angular speed of the three wheels reduced the rate of seed filling in the seed filling regions by gravity and disturbances.In addition,an analysis of the repose angle formed by the dropped seed indicated that the angular speed of the taking seed wheel has a certain effect.The large angular speed reduced the coefficient of variation of the seed drop location.The repose angle of the horse tooth seed was greater than those of the other.Meanwhile,the irregular maize seed can also reduce the coefficient of variation of the seed drop location.A comparison between the simulation and experiment results indicates the number of metering seed were basically the same.
基金Supported by the Scientific Research Fund of Hunan Provincial Education Department(21A048)Graduate Student Research Innovation Project of Shaoyang University(CX2022SY080)Transverse project of Shaoyang University(2023HX37,2023HX43)。
文摘[Objectives] This study was conducted to improve the nutritional value of soybean milk, enrich the variety and taste of soybean milk, and find healthy food that is more conducive to people s nutritional needs. [Methods] Whole soybean milk was prepared by grinding with a grinding wheel at a low concentration (low-concentration grinding) and a stainless steel mill at a high concentration (high-concentration grinding). The sensory, physical and chemical characteristics and anti-nutritional factors of whole soybean milk produced by different grinding methods were studied. [Results] Compared with low-concentration grinding, the protein content in soybean milk prepared by high-concentration grinding increased by 24%, and the dietary fiber content increased by 74.7%. Before and after high-pressure homogenization, the particle size D(4, 3) of soybean milk prepared by low-concentration grinding was 212.1 and 93.59 μm, respectively, and the particle size D(4, 3) of soybean milk prepared by high-concentration grinding was 134.0 and 64.64 μm, respectively. The trypsin inhibitor activity and phytic acid content of soybean milk prepared by high-concentration grinding were significantly lower than those of soybean milk prepared by low-concentration grinding. [Conclusions] This study improves the diet structure of the broad masses of people, strengthens people s physique, and provides a new idea for the implementation and development of China s "Soybean Action Programme".
