We extend a theorem of Ivanev and Saff to show that for the Hermite-Pade interpolant at the roots of unity to a function meromorphic in the unit disc, its leading coefficients vanish if and only if the corresponding i...We extend a theorem of Ivanev and Saff to show that for the Hermite-Pade interpolant at the roots of unity to a function meromorphic in the unit disc, its leading coefficients vanish if and only if the corresponding interpolani to a related function vanishes at given points outside the unit disc. The result is then extended to simultaneous Hermite-Pade interpolation to a finite set of functions.展开更多
Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s modulus.However,the extent to which and how these biomechanical properties of herbaceou...Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s modulus.However,the extent to which and how these biomechanical properties of herbaceous roots are influenced remain unknown.To better understand the behavior of roots in tension under different conditions and to illustrate these behaviors,uniaxial tensile tests were conducted on the Poa araratica roots as the gauge length increased from 20 mm to 80 mm.Subsequently,ANOVA was used to test the impact of the significant influences of gauge length on the biomechanical properties,nonlinear regression was applied to establish the variation in the biomechanical properties with gauge length to answer the question of the extent to which the biomechanical properties are influenced,and Weibull models were subsequently introduced to illustrate how the biomechanical properties are influenced by gauge length.The results reveal that(1)the variation in biomechanical properties with root diameter depends on both the gauge length and the properties themselves;(2)the gauge length significantly impacts most of the biomechanical properties;(3)the tensile resistance,tensile strength,and tensile strain at cracks decrease as the gauge length increases,with values decreasing by 20%-300%,while Young’s modulus exhibits the opposite trend,with a corresponding increase of 30%;and(4)the Weibull distribution is suitable for describing the probability distribution of these biomechanical properties;the Weibull modulus for both tensile resistance and tensile strain at cracks linearly decrease with gauge length,whereas those for tensile strength and Young’s modulus exhibit the opposite trend.The tensile resistance,tensile strength,and tensile strain at the cracks linearly decrease with increasing gauge length,while the tensile strength and Young’s modulus linearly increase with increasing gauge length.展开更多
The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica,a member of family Ebenaceae. TEM an...The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica,a member of family Ebenaceae. TEM analysis revealed the average diameter of Ag NPs around 8 nm which is in good agreement with the average crystallite size（10 nm）calculated from X-ray Diffraction（XRD）analysis. Further the study has been extended to the antimicrobial activity against test pathogenic Gram（＋）ve,Gram（-）ve bacterial and fungal strains. The bioinspired Ag-NP showed promising activity against all the tested bacterial strains and the activity was enhanced with increased dosage levels展开更多
Root pullout performance of plants is an important mechanical basis for soil reinforcement by plant roots in the semi-arid areas.Studies have shown that it is affected by plant factors(species,ages,root geometry,etc.)...Root pullout performance of plants is an important mechanical basis for soil reinforcement by plant roots in the semi-arid areas.Studies have shown that it is affected by plant factors(species,ages,root geometry,etc.)and soil factors(soil types,soil moisture,soil bulk densities,etc.).However,the effects of loading rates on root pullout performance are not well studied.To explore the mechanical interactions under different loading rates,we conducted pullout tests on Medicago sativa L.and Hippophae rhamnoides L.roots under five loading rates,i.e.,5,50,100,150,and 200 mm/min.In addition,tensile tests were conducted on the roots in diameters of 0.5-2.0 mm to compare the relationship between root tensile properties and root pullout properties.Results showed that two root failure modes,slippage and breakage,were observed during root pullout tests.All M.sativa roots were pulled out,while 72.2%of H.rhamnoides roots were broken.The maximum fracture diameter and fracture root length of H.rhamnoides were 1.22 mm and 7.44 cm under 100 mm/min loading rate,respectively.Root displacement values were 4.63%(±0.43%)and 8.91%(±0.52%)of the total root length for M.sativa and H.rhamnoides,respectively.The values of maximum pullout force were 14.6(±0.7)and 17.7(±1.8)N under 100 mm/min for M.sativa and H.rhamnoides,respectively.Values of the maximum pullout strength for M.sativa and H.rhamnoides were 38.38(±5.48)MPa under 150 mm/min and 12.47(±1.43)MPa under 100 mm/min,respectively.Root-soil friction coefficient under 100 mm/min was significantly larger than those under other loading rates for both the two species.Values of the maximum root pullout energy for M.sativa and H.rhamnoides were 87.83(±21.55)mm•N under 100 mm/min and 173.53(±38.53)mm•N under 200 mm/min,respectively.Root pullout force was significantly related to root diameter(P<0.01).Peak root pullout force was significantly affected by loading rates when the effect of root diameter was included(P<0.01),and vice versa.Except for the failure mode and peak pullout force,other pullout parameters,including root pullout strength,root displacement,root-soil friction coefficient,and root pullout energy were not significantly affected by loading rates(P>0.05).Root pullout strength was greater than root tensile strength for the two species.The results suggested that there was no need to deliberately control loading rate in root pullout tests in the semi-arid soil,and root pullout force and pullout strength could be better parameters for root reinforcement model compared with root tensile strength as root pullout force and pullout strength could more realistically reflect the working state of roots in the semi-arid soil.展开更多
Soil erosion and shallow landslides in the upper reaches of the Yellow River,China,are increasing due to extreme climate events and human disturbances.The biomechanical properties of vegetation roots play an important...Soil erosion and shallow landslides in the upper reaches of the Yellow River,China,are increasing due to extreme climate events and human disturbances.The biomechanical properties of vegetation roots play an important role in soil stabilization and fixation,as they resist soil erosion and shallow landslides in this area.However,the biomechanical properties of the roots of dominant herbs and their influencing factors in this area remain poorly understood.Therefore,we selected two dominant herbs in this area,Stipa aliena Keng and Poa crymophila Keng,and carried out a series of uniaxial tensile tests on the roots of the two herbs under different treatments.Meanwhile,the effects of root diameter,plant species,gauge length,root water content,and loading rate on the biomechanical properties of the two herbs'roots were analyzed.The results showed that root diameter was the most significant factor affecting the root biomechanical properties(P<0.010),and root tensile force displayed a positive power law relationship with root diameter,whereas root tensile strength and Young's modulus followed negative power law correlations with root diameter,and fracture strain increased linearly with root diameter.Root tensile force,tensile strength,and fracture strain of S.aliena were significantly greater than those of P.crymophila(P<0.001),which was mainly due to the higher lignin content and lignin:cellulose ratio of S.aliena roots.During uniaxial tensile process,hydrated roots exhibited elastic-plastic-brittle behavior,whereas dried roots exhibited elastic-brittle behavior.Root fracture strain of the two herbs was significantly lower under 100 mm gauge length than under 50 mm gauge length(P<0.001),and the Young's modulus was significantly greater(P<0.050).Tensile strength and fracture strain of hydrated roots of the two herbs were significantly greater than those of dried roots(P<0.050),whereas the Young's modulus was significantly lower(P<0.001).Root tensile force,tensile strength,and fracture strain of S.aliena were significantly greater under 20 mm/min loading rate than under 200 mm/min loading rate(P<0.050),whereas loading rate had no significant effect on the root biomechanical properties of P.crymophila(P>0.050).Fibrous roots of the two herbs were well developed,with relatively high tensile strengths and Young's moduli of 78.498 and 837.901 MPa for S.aliena,and 67.541 and 901.184 MPa for P.crymophila,respectively.The two herbs can stabilize soil and prevent soil erosion and can be used as pioneer species for ecological restoration in the upper reaches of the Yellow River.These results provide a theoretical basis for soil erosion and shallow landslide control in the giant landslide area of the upper reaches of the Yellow River.展开更多
We discuss the general solutions of polynomial systems in complex domain and prove the existence of global general solutions by applying the generalized Strong Rooted Theorem of complex polynomial systems.
文摘We extend a theorem of Ivanev and Saff to show that for the Hermite-Pade interpolant at the roots of unity to a function meromorphic in the unit disc, its leading coefficients vanish if and only if the corresponding interpolani to a related function vanishes at given points outside the unit disc. The result is then extended to simultaneous Hermite-Pade interpolation to a finite set of functions.
基金financially supported by the Key R&D Program of Shaanxi Province(2023-YBSF-324)Shaanxi Provincial Department of Education Services Local Special Plan Project(23JC019)National Natural Science of Foundation of China(42267024).
文摘Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s modulus.However,the extent to which and how these biomechanical properties of herbaceous roots are influenced remain unknown.To better understand the behavior of roots in tension under different conditions and to illustrate these behaviors,uniaxial tensile tests were conducted on the Poa araratica roots as the gauge length increased from 20 mm to 80 mm.Subsequently,ANOVA was used to test the impact of the significant influences of gauge length on the biomechanical properties,nonlinear regression was applied to establish the variation in the biomechanical properties with gauge length to answer the question of the extent to which the biomechanical properties are influenced,and Weibull models were subsequently introduced to illustrate how the biomechanical properties are influenced by gauge length.The results reveal that(1)the variation in biomechanical properties with root diameter depends on both the gauge length and the properties themselves;(2)the gauge length significantly impacts most of the biomechanical properties;(3)the tensile resistance,tensile strength,and tensile strain at cracks decrease as the gauge length increases,with values decreasing by 20%-300%,while Young’s modulus exhibits the opposite trend,with a corresponding increase of 30%;and(4)the Weibull distribution is suitable for describing the probability distribution of these biomechanical properties;the Weibull modulus for both tensile resistance and tensile strain at cracks linearly decrease with gauge length,whereas those for tensile strength and Young’s modulus exhibit the opposite trend.The tensile resistance,tensile strength,and tensile strain at the cracks linearly decrease with increasing gauge length,while the tensile strength and Young’s modulus linearly increase with increasing gauge length.
基金the BK 21 PLUS programme for Post Doctoral Fellowship and DST-PURSE Programme No.SR/S9/2-23-2015 for the financial assistance and Advanced Analytical Laboratory,Andhra University
文摘The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica,a member of family Ebenaceae. TEM analysis revealed the average diameter of Ag NPs around 8 nm which is in good agreement with the average crystallite size（10 nm）calculated from X-ray Diffraction（XRD）analysis. Further the study has been extended to the antimicrobial activity against test pathogenic Gram（＋）ve,Gram（-）ve bacterial and fungal strains. The bioinspired Ag-NP showed promising activity against all the tested bacterial strains and the activity was enhanced with increased dosage levels
基金supported by the Natural Science Foundation of Shanxi Province of China(20210302123105)the Shanxi Scholarship Council of China(2020-054)the Changjiang River Scientific Research Institute(CRSRI)Open Research Program(CKWV20221006/KY).
文摘Root pullout performance of plants is an important mechanical basis for soil reinforcement by plant roots in the semi-arid areas.Studies have shown that it is affected by plant factors(species,ages,root geometry,etc.)and soil factors(soil types,soil moisture,soil bulk densities,etc.).However,the effects of loading rates on root pullout performance are not well studied.To explore the mechanical interactions under different loading rates,we conducted pullout tests on Medicago sativa L.and Hippophae rhamnoides L.roots under five loading rates,i.e.,5,50,100,150,and 200 mm/min.In addition,tensile tests were conducted on the roots in diameters of 0.5-2.0 mm to compare the relationship between root tensile properties and root pullout properties.Results showed that two root failure modes,slippage and breakage,were observed during root pullout tests.All M.sativa roots were pulled out,while 72.2%of H.rhamnoides roots were broken.The maximum fracture diameter and fracture root length of H.rhamnoides were 1.22 mm and 7.44 cm under 100 mm/min loading rate,respectively.Root displacement values were 4.63%(±0.43%)and 8.91%(±0.52%)of the total root length for M.sativa and H.rhamnoides,respectively.The values of maximum pullout force were 14.6(±0.7)and 17.7(±1.8)N under 100 mm/min for M.sativa and H.rhamnoides,respectively.Values of the maximum pullout strength for M.sativa and H.rhamnoides were 38.38(±5.48)MPa under 150 mm/min and 12.47(±1.43)MPa under 100 mm/min,respectively.Root-soil friction coefficient under 100 mm/min was significantly larger than those under other loading rates for both the two species.Values of the maximum root pullout energy for M.sativa and H.rhamnoides were 87.83(±21.55)mm•N under 100 mm/min and 173.53(±38.53)mm•N under 200 mm/min,respectively.Root pullout force was significantly related to root diameter(P<0.01).Peak root pullout force was significantly affected by loading rates when the effect of root diameter was included(P<0.01),and vice versa.Except for the failure mode and peak pullout force,other pullout parameters,including root pullout strength,root displacement,root-soil friction coefficient,and root pullout energy were not significantly affected by loading rates(P>0.05).Root pullout strength was greater than root tensile strength for the two species.The results suggested that there was no need to deliberately control loading rate in root pullout tests in the semi-arid soil,and root pullout force and pullout strength could be better parameters for root reinforcement model compared with root tensile strength as root pullout force and pullout strength could more realistically reflect the working state of roots in the semi-arid soil.
基金funded by the National Natural Science Foundation of China(42267024,42041006)the Youth Research Fund Project of Qinghai University,China(2023-QGY-10).
文摘Soil erosion and shallow landslides in the upper reaches of the Yellow River,China,are increasing due to extreme climate events and human disturbances.The biomechanical properties of vegetation roots play an important role in soil stabilization and fixation,as they resist soil erosion and shallow landslides in this area.However,the biomechanical properties of the roots of dominant herbs and their influencing factors in this area remain poorly understood.Therefore,we selected two dominant herbs in this area,Stipa aliena Keng and Poa crymophila Keng,and carried out a series of uniaxial tensile tests on the roots of the two herbs under different treatments.Meanwhile,the effects of root diameter,plant species,gauge length,root water content,and loading rate on the biomechanical properties of the two herbs'roots were analyzed.The results showed that root diameter was the most significant factor affecting the root biomechanical properties(P<0.010),and root tensile force displayed a positive power law relationship with root diameter,whereas root tensile strength and Young's modulus followed negative power law correlations with root diameter,and fracture strain increased linearly with root diameter.Root tensile force,tensile strength,and fracture strain of S.aliena were significantly greater than those of P.crymophila(P<0.001),which was mainly due to the higher lignin content and lignin:cellulose ratio of S.aliena roots.During uniaxial tensile process,hydrated roots exhibited elastic-plastic-brittle behavior,whereas dried roots exhibited elastic-brittle behavior.Root fracture strain of the two herbs was significantly lower under 100 mm gauge length than under 50 mm gauge length(P<0.001),and the Young's modulus was significantly greater(P<0.050).Tensile strength and fracture strain of hydrated roots of the two herbs were significantly greater than those of dried roots(P<0.050),whereas the Young's modulus was significantly lower(P<0.001).Root tensile force,tensile strength,and fracture strain of S.aliena were significantly greater under 20 mm/min loading rate than under 200 mm/min loading rate(P<0.050),whereas loading rate had no significant effect on the root biomechanical properties of P.crymophila(P>0.050).Fibrous roots of the two herbs were well developed,with relatively high tensile strengths and Young's moduli of 78.498 and 837.901 MPa for S.aliena,and 67.541 and 901.184 MPa for P.crymophila,respectively.The two herbs can stabilize soil and prevent soil erosion and can be used as pioneer species for ecological restoration in the upper reaches of the Yellow River.These results provide a theoretical basis for soil erosion and shallow landslide control in the giant landslide area of the upper reaches of the Yellow River.
文摘We discuss the general solutions of polynomial systems in complex domain and prove the existence of global general solutions by applying the generalized Strong Rooted Theorem of complex polynomial systems.
