Materials with low thermal conductivity are applied extensively in energy management,and breaking the amorphous limits of thermal conductivity to solids has attracted widespread attention from scientists.Doping is a c...Materials with low thermal conductivity are applied extensively in energy management,and breaking the amorphous limits of thermal conductivity to solids has attracted widespread attention from scientists.Doping is a common strategy for achieving low thermal conductivity that can offer abundant scattering centers in which heavier dopants always result in lower phonon group velocities and lower thermal conductivities.However,the amount of equivalent heavyatom single dopant available is limited.Unfortunately,nonequivalent heavy dopants have finite solubility because of charge imbalance.Here,we propose a charge balance strategy for SnS by substituting Sn2+with Ag^(+)and heavy Bi^(3+),improving the doping limit of Ag from 2%to 3%.Ag and Bi codoping increases the point defect concentration and introduces abundant boundaries simultaneously,scattering the phonons at both the atomic scale and nanoscale.The thermal conductivity of Ag0.03Bi0.03Sn0.94S decreased to 0.535 W·m^(−1)·K^(−1)at room temperature and 0.388 W·m^(−1)·K^(−1)at 275°C,which is below the amorphous limit of 0.450 W·m^(−1)·K^(−1)for SnS.This strategy offers a simple way to enhance the doping limit and achieve ultralow thermal conductivity in solids below the amorphous limit without precise structural modification.展开更多
An algorithm for partitioning arbitrary simple polygons into a number of convex parts was presented. The concave vertices were determined first, and then they were moved by using the method connecting the concave vert...An algorithm for partitioning arbitrary simple polygons into a number of convex parts was presented. The concave vertices were determined first, and then they were moved by using the method connecting the concave vertices with the vertices of falling into its region B,so that the primary polygon could be partitioned into two subpolygons. Finally, this method was applied recursively to the subpolygons until all the concave vertices were removed. This algorithm partitions the polygon into O(l) convex parts, its time complexity is max(O(n),O(l 2)) multiplications, where n is the number of vertices of the polygon and l is the number of the concave vertices.展开更多
In this paper, the fixed-point Theorem i s used to estimate an asymptotic solution of boundary value problems for a class o f third order quasilinear differential equation and the uniformly valid asymptot ic expansio...In this paper, the fixed-point Theorem i s used to estimate an asymptotic solution of boundary value problems for a class o f third order quasilinear differential equation and the uniformly valid asymptot ic expansion of solution of any orders including boundary layer is obtained.展开更多
The self-incompatibility ( S) loci from the Solanaceae, Rosaceae and Scrophulariaceae encode a class of ribonucleases, known as S RNases, which have been shown to control the pistil expression of self-incompatible rea...The self-incompatibility ( S) loci from the Solanaceae, Rosaceae and Scrophulariaceae encode a class of ribonucleases, known as S RNases, which have been shown to control the pistil expression of self-incompatible reaction. In the former two families, the S loci have been shown to be located near centromere. However, the chromosomal location of the S locus in Antirrhinum, a species of the Scrophulariaceae, is not known. To determine its chromosomal location and genomic organization, an S-2 RNase gene and its corresponding 63 kb BAC clone were separately used for fluorescence in situ hybridization (FISH) of mitotic metaphase chromosomes of a self-incompatible Antirrhinum line Of S2S5. The results showed that the S-2 RNase detected a doublet signal near the centromere of the smallest chromosome (2n = 16). Two separate doublet signals of the tested BAC sequence were shown on both sides of the centromeres of all eight pairs of the chromosomes, suggesting that the Antirrhinum S locus is located in a pericentromeric region. Furthermore, a retrotransposon, named RIS1 (retrotransposon in the S locus), which has not been identified yet in. Antirrhinum, was found next to S-2 RNase. Taken together, the centromeric location of the S locus from the three S-RNase-based self-incompatible families provides a further support on a common origin of their evolution as well as suppressed recombination.展开更多
The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming（SPIF） was studied. The flange is produced in four stages starting from 45° ...The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming（SPIF） was studied. The flange is produced in four stages starting from 45° to 90° and employing aluminum as the test material. It is shown that the hole size has significant effects on the stress/strain distribution on the cylindrical flange. The magnitude of hoop strains increases and the flange thickness increases as the hole size increases. Likewise, the von Mises stress reduces with the increasing of hole size. Further, there is a threshold value of hole size（i.e., 80 mm） below which severe stresses occur, which lead to sheet fracturing thus failing the successful forming of cylindrical flange. Moreover, the formability reduces as the hole size is increased above the threshold size. Finally, it is concluded that 80 mm is the threshold size of hole for maximizing the formability of aluminum sheet in incremental hole flanging.展开更多
By applying fixed point theorem, the existence of positive solution is considered for superlinear semipositone singular m-point boundary value problem -（Lφ）（x）=（p（x）φ′（x））′＋q（x）φ（x） and ξi ∈ （0,...By applying fixed point theorem, the existence of positive solution is considered for superlinear semipositone singular m-point boundary value problem -（Lφ）（x）=（p（x）φ′（x））′＋q（x）φ（x） and ξi ∈ （0,1）with 0〈ξ1〈ξ2……〈ξm-2〈1,αi ∈ R^＋,f ∈C[（0,1）×R^＋,R^＋],f（x,φ） may be singular at x=0 and x=1,g（x）：（0,1）→R is Lebesgue measurable, g may tend to negative infinity and have finitely many singularities.展开更多
基金supported by the CAS Project for Young Scientists in Basic Research(YSBR-070)the National Natural Science Foundation of China(21925110,21890750,U2032161,12147105)+8 种基金the USTC Research Funds of the Double First-Class Initiative(YD2060002004)the National Key Research and Development Program of China(2022YFA1203600,2022YFA1203601,2022YFA1203602)the Natural Science Foundation of China-Anhui Joint Fund(U23A20121)the Outstanding Youth Foundation of Anhui Province(2208085J14)the Anhui Provincial Key Research and Development Project(202004a050200760)the Key R&D Program of Shandong Province(2021CXGC010302)the Users with Excellence Project of Hefei Science Center CAS(2021HSC-UE004)the Fellowship of the China Postdoctoral Science Foundation(2022M710141)the open foundation of the Key Laboratory of the Engineering Research Center of Building Energy Efficiency Control and Evaluation,Ministry of Education(AHJZNX-2023-04).
文摘Materials with low thermal conductivity are applied extensively in energy management,and breaking the amorphous limits of thermal conductivity to solids has attracted widespread attention from scientists.Doping is a common strategy for achieving low thermal conductivity that can offer abundant scattering centers in which heavier dopants always result in lower phonon group velocities and lower thermal conductivities.However,the amount of equivalent heavyatom single dopant available is limited.Unfortunately,nonequivalent heavy dopants have finite solubility because of charge imbalance.Here,we propose a charge balance strategy for SnS by substituting Sn2+with Ag^(+)and heavy Bi^(3+),improving the doping limit of Ag from 2%to 3%.Ag and Bi codoping increases the point defect concentration and introduces abundant boundaries simultaneously,scattering the phonons at both the atomic scale and nanoscale.The thermal conductivity of Ag0.03Bi0.03Sn0.94S decreased to 0.535 W·m^(−1)·K^(−1)at room temperature and 0.388 W·m^(−1)·K^(−1)at 275°C,which is below the amorphous limit of 0.450 W·m^(−1)·K^(−1)for SnS.This strategy offers a simple way to enhance the doping limit and achieve ultralow thermal conductivity in solids below the amorphous limit without precise structural modification.
文摘An algorithm for partitioning arbitrary simple polygons into a number of convex parts was presented. The concave vertices were determined first, and then they were moved by using the method connecting the concave vertices with the vertices of falling into its region B,so that the primary polygon could be partitioned into two subpolygons. Finally, this method was applied recursively to the subpolygons until all the concave vertices were removed. This algorithm partitions the polygon into O(l) convex parts, its time complexity is max(O(n),O(l 2)) multiplications, where n is the number of vertices of the polygon and l is the number of the concave vertices.
文摘In this paper, the fixed-point Theorem i s used to estimate an asymptotic solution of boundary value problems for a class o f third order quasilinear differential equation and the uniformly valid asymptot ic expansion of solution of any orders including boundary layer is obtained.
文摘The self-incompatibility ( S) loci from the Solanaceae, Rosaceae and Scrophulariaceae encode a class of ribonucleases, known as S RNases, which have been shown to control the pistil expression of self-incompatible reaction. In the former two families, the S loci have been shown to be located near centromere. However, the chromosomal location of the S locus in Antirrhinum, a species of the Scrophulariaceae, is not known. To determine its chromosomal location and genomic organization, an S-2 RNase gene and its corresponding 63 kb BAC clone were separately used for fluorescence in situ hybridization (FISH) of mitotic metaphase chromosomes of a self-incompatible Antirrhinum line Of S2S5. The results showed that the S-2 RNase detected a doublet signal near the centromere of the smallest chromosome (2n = 16). Two separate doublet signals of the tested BAC sequence were shown on both sides of the centromeres of all eight pairs of the chromosomes, suggesting that the Antirrhinum S locus is located in a pericentromeric region. Furthermore, a retrotransposon, named RIS1 (retrotransposon in the S locus), which has not been identified yet in. Antirrhinum, was found next to S-2 RNase. Taken together, the centromeric location of the S locus from the three S-RNase-based self-incompatible families provides a further support on a common origin of their evolution as well as suppressed recombination.
文摘The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming（SPIF） was studied. The flange is produced in four stages starting from 45° to 90° and employing aluminum as the test material. It is shown that the hole size has significant effects on the stress/strain distribution on the cylindrical flange. The magnitude of hoop strains increases and the flange thickness increases as the hole size increases. Likewise, the von Mises stress reduces with the increasing of hole size. Further, there is a threshold value of hole size（i.e., 80 mm） below which severe stresses occur, which lead to sheet fracturing thus failing the successful forming of cylindrical flange. Moreover, the formability reduces as the hole size is increased above the threshold size. Finally, it is concluded that 80 mm is the threshold size of hole for maximizing the formability of aluminum sheet in incremental hole flanging.
基金Foundation item： Supported by the National Natural Science Foundation of China（10671167） Supported by the Research Foundation of Liaocheng University（31805）
文摘By applying fixed point theorem, the existence of positive solution is considered for superlinear semipositone singular m-point boundary value problem -（Lφ）（x）=（p（x）φ′（x））′＋q（x）φ（x） and ξi ∈ （0,1）with 0〈ξ1〈ξ2……〈ξm-2〈1,αi ∈ R^＋,f ∈C[（0,1）×R^＋,R^＋],f（x,φ） may be singular at x=0 and x=1,g（x）：（0,1）→R is Lebesgue measurable, g may tend to negative infinity and have finitely many singularities.
