In this paper,we consider the forced neutral advanced dynamic equations with positive and negative coeffcients[x(t)-R(t)x(t+r)]+P(t)x(t+τ)△Q(t)x(t+δ)= f(t),t≥t0 on a time scale T.Several suffcient conditions are o...In this paper,we consider the forced neutral advanced dynamic equations with positive and negative coeffcients[x(t)-R(t)x(t+r)]+P(t)x(t+τ)△Q(t)x(t+δ)= f(t),t≥t0 on a time scale T.Several suffcient conditions are obtained for the oscillation of the dynamic equations.The main result is illustrated by an example.展开更多
We discuss the relations among the best approximation En(f) and the Fourier coeffcients of a function, f(n) ∈ C,n = 0,±1,±2,..., under the conditions that {f (n)}∞n=0 ∈ MVBVS* and {f (n) + f(n)}∞n=0 ∈ M...We discuss the relations among the best approximation En(f) and the Fourier coeffcients of a function, f(n) ∈ C,n = 0,±1,±2,..., under the conditions that {f (n)}∞n=0 ∈ MVBVS* and {f (n) + f(n)}∞n=0 ∈ MVBVS*, where MVBVS* is the class of the so-called Strong Mean Value Bounded Variation Sequences.展开更多
The main purpose of this paper is to investigate the univalence of normalized polyharmonic mappings with bounded length distortions in the unit disk.We first establish the coefficient estimates for polyharmonic mappin...The main purpose of this paper is to investigate the univalence of normalized polyharmonic mappings with bounded length distortions in the unit disk.We first establish the coefficient estimates for polyharmonic mappings with bounded length distortions.Then,using these results,we establish five Landau-type theorems for subclasses of polyharmonic mappings F and L(F),where F has bounded length distortion and L is a differential operator.展开更多
A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes thr...A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes three elastic constants of single cubic crystal and ?ve texture coe?cients, accounts for the e?ects of the orientation distribution function (ODF) up to terms linear in the tex- ture coe?cients. Thus it is expected that our formula would be applicable to arbitrary aggregates with weak texture or to materials such as aluminum whose single crystal has weak anisotropy. Three examples are presented to compare predictions from our formula with those from Nishioka and Lothe’s formula and Synge’s contour integral through numerical integration. As an applica- tion of Green’s function, we brie?y describe the procedure of deriving the e?ective elastic sti?ness tensor for an orthorhombic aggregate of cubic crystallites. The comparison of the computational results given by the ?nite element method and our e?ective elastic sti?ness tensor is made by an example.展开更多
The stress-strain-resistance relations of the Fe-Mn-Si alloys with different Si content have been investigated by measuring strain (ε) and resistance (△ R/R) upon tension synchronously. The results show that the str...The stress-strain-resistance relations of the Fe-Mn-Si alloys with different Si content have been investigated by measuring strain (ε) and resistance (△ R/R) upon tension synchronously. The results show that the strum induced γ→ε martensitic transfor- mation increases the strain sensitivity coeffcient of resistance (K) for the Fe-Mn-Si alloys in plastic region. There is a critical strum where dσ/dε becomes a constant value. Si increases the critical strum. A correlation between the critical strain and shape memory effect (SME) in the Fe-Mn-Si alloys is suggested.展开更多
The parameter estimation and the coefficient of contamination for the regression models with repeated measures are studied when its response variables are contaminated by another random variable sequence.Under the sui...The parameter estimation and the coefficient of contamination for the regression models with repeated measures are studied when its response variables are contaminated by another random variable sequence.Under the suitable conditions it is proved that the estimators which are established in the paper are strongly consistent estimators.展开更多
The equilibrium solubilities,volumetric gas-liquid mass transfer coefficients kLa of H_2 and CO were measured as functions of temperature(298―513 K),pressure(1―3 MPa),superficial gas velocity(0.5―3 cm/s) and solid ...The equilibrium solubilities,volumetric gas-liquid mass transfer coefficients kLa of H_2 and CO were measured as functions of temperature(298―513 K),pressure(1―3 MPa),superficial gas velocity(0.5―3 cm/s) and solid volume fraction(5%―25%) in liquid paraffin/iron-based catalyst slurry bubble column reactor.The volumetric mass transfer coefficients kLa were obtained by measuring the dissolution rate of H_2 and CO.The influences of the operation conditions,such as pressure,temperature,superficial gas velocity and catalyst concentration on kLa,were investigated.Two empirical correlations were proposed to predict kLa values of H_2 and CO in liquid paraffin/solid particles slurry bubble column reactor.The results showed that the equilibrium solubilities of H-2 and CO increased with an increasing temperature and pressure,and the solubility of CO was greater than that for H_2.It was found that the equilibrium solubility can be expressed by Henry's law.The volumetric mass transfer coefficients of H_2 and CO were of the same order of magnitude,and increased with the increase of pressure,temperature and superficial gas velocity.The presence of solid particles decreased kLa values of both H_2 and CO.展开更多
Expressing the excess partial molar free energies and integral excess free energy as poly- nome of the composition,then the parameters in the expression of excess partial molar free energy of C were evaluated based on...Expressing the excess partial molar free energies and integral excess free energy as poly- nome of the composition,then the parameters in the expression of excess partial molar free energy of C were evaluated based on:the excess partial free energy of C in C-Fe bi- nary alloy:the integral excess free energy of Fe-X binary alloy:the C saturation curve and the iso-activity curve of C (α_c=0.025) in the ternary system.Then the activity coefficient of X was evaluated with the so-called “I-D” method,by which the component activities of every element in the whole molten ternary alloy can be evaluated,and the results are in good agreement with literature data based on experiment.展开更多
We define new integral operators on the Haydy space similar to Szeg<span style="white-space:nowrap;"><span style="white-space:nowrap;">ö<span style="font-family:Verdana...We define new integral operators on the Haydy space similar to Szeg<span style="white-space:nowrap;"><span style="white-space:nowrap;">ö<span style="font-family:Verdana;"> projection. We show that these operators map from <span style="font-family:Verdana;">H<sup><i style="white-space:normal;"><span style="font-family:Verdana;">p</sup><span style="font-family:Verdana;"> <span style="font-family:Verdana;">to <span style="font-family:Verdana;">H<span style="font-family:Verdana;"><sup><span style="white-space:normal;font-family:Verdana;">2 </sup><span style="font-family:Verdana;">for some 1 <span style="font-family:Verdana;">≤ <span style="font-family:Verdana;">p < <span style="font-family:Verdana;">2, where the range of <span style="font-family:Verdana;">p <span style="font-family:CMR10;"><span style="font-family:Verdana;">is depending on a growth condition. To prove that, we generalize the Hausdorff-Young Theorem to multi-dimensional case.展开更多
Tree allometric models based on height(H)and diameter(D)are the most commonly used method to estimate forest biomass.Environments and stand characteristics are recognized to affect tree allometries.However,few studies...Tree allometric models based on height(H)and diameter(D)are the most commonly used method to estimate forest biomass.Environments and stand characteristics are recognized to affect tree allometries.However,few studies have considered to incorporate these effects into allometric models,which restricts the use of these models in a wide domain.Adopting the power-law function Y=aG^(b) as a basic model where Y is either tree height or biomass and the corresponding G is tree diameter D at breast height or D^(2)H,we developed a two-step approximation procedure to quantify the effects of environments and stand characteristics on allometric coeffcients a and b for Cunninghamia lanceolata and Pinus forest in China.Results show that most of the allometric coeffcients are dependent on stand characteristics for C.lanceolata forest,and on mean annual temperature,stand age and latitude for Pinus forest.The allometric models via the two-step approximation Y=f(α+α_(j)x_(j))G^(f(β+βixi))(x_(j) or x_(i) are key drivers associated with environments and stand characteristics.α,αj,βandβi are regression coeffcients)considerably improved the accuracy of tree height and biomass estimation.Compared to the basic model,the second approximation models signifcantly reduced the mean absolute bias between the observed and computed values by 25%-34%for C.lanceolata and by 21%-26%for Pinus forest,respectively.Our results highlight the necessity of incorporating environments and stand characteristics into the allometric models and provide a universal method to accurately estimate H-D-based tree biomass across a wider domain.展开更多
Let X be a complex Banach space with norm · , B be the unit ball in X, Dn be the unit polydisc in Cn. In this paper, we introduce a class of holomorphic mappings Mg on B or Dn. Let f(x) be a normalized locally bi...Let X be a complex Banach space with norm · , B be the unit ball in X, Dn be the unit polydisc in Cn. In this paper, we introduce a class of holomorphic mappings Mg on B or Dn. Let f(x) be a normalized locally biholomorphic mapping on B such that (Df(x))-1f(x) ∈ Mg and f(x) - x has a zero of order k + 1 at x = 0. We obtain coeffcient estimates for f(x). These results unify and generalize many known results.展开更多
This paper concerns the reconstruction of a scalar coefficient of a second-order elliptic equation in divergence form posed on a bounded domain from internal data.This problem finds applications in multi-wave imaging,...This paper concerns the reconstruction of a scalar coefficient of a second-order elliptic equation in divergence form posed on a bounded domain from internal data.This problem finds applications in multi-wave imaging,greedy methods to approximate parameter-dependent elliptic problems,and image treatment with partial differential equations.We first show that the inverse problem for smooth coefficients can be rewritten as a linear transport equation.Assuming that the coefficient is known near the boundary,we study the well-posedness of associated transport equation as well as its numerical resolution using discontinuous Galerkin method.We propose a regularized transport equation that allow us to derive rigorous convergence rates of the numerical method in terms of the order of the polynomial approximation as well as the regularization parameter.We finally provide numerical examples for the inversion assuming a lower regularity of the coefficient,and using synthetic data.展开更多
A dynamical statistical model is used to analyze the experimental shape isomer yields data in the reaction d＋240Pu at E=20–29 MeV.The possibility of determining the nuclear dissipation is discussed.Comparison of the...A dynamical statistical model is used to analyze the experimental shape isomer yields data in the reaction d＋240Pu at E=20–29 MeV.The possibility of determining the nuclear dissipation is discussed.Comparison of the experimental data with the calculations leads to a value of the reduced dissipation coeffcient β=0.45×1021 s-1 for the Am isotopes.展开更多
Ethanol-water binary mixtures with 7 different mole fractions of ethanol ranging from 0 to 1 were adopted as testing liquids in the experiment. The vertical heating tube was inserted in porous matrix composed of five ...Ethanol-water binary mixtures with 7 different mole fractions of ethanol ranging from 0 to 1 were adopted as testing liquids in the experiment. The vertical heating tube was inserted in porous matrix composed of five well sorted glass beads whose diameters range from 0.5 to 4.3 mm. Due to the effect of composition, the trend of combination of vapor bubbles was reduced, resulting in the increase of peak heat flux of binary mixture. With the increase of ethanol mole fraction, 0.5 mm diameter bead had lower value of peak heat flux, while for pure liquid the critical state is difficult to appear. With given diameter of glass bead, there existed an optimum value of mole fraction of ethanol, which was decreased with the increase of bead diameter. A dimensionless heat transfer coefficient was predicted through the introduction of a dimensionless parameter of porous matrix, which agreed with the experimental results satisfactorily.展开更多
基金Supported by the the NNSF of China（60404022 60604004） Supported by the Special Projects in Mathematics Funded by Natural Science Foundation of Hebei Province（07M005）
文摘In this paper,we consider the forced neutral advanced dynamic equations with positive and negative coeffcients[x(t)-R(t)x(t+r)]+P(t)x(t+τ)△Q(t)x(t+δ)= f(t),t≥t0 on a time scale T.Several suffcient conditions are obtained for the oscillation of the dynamic equations.The main result is illustrated by an example.
基金NSERC RCD grant and AARMS of Canada (Yu D S)by NSERC of Canada(Zhou P)+2 种基金by the National Natural Science Foundation of China (Grant No. 10471130)the Open Fund(Grant No. PLN0613) of State Key Laboratory of OilGas Reservoir Geology and Exploitation (Southwest Petroleum University) (Zhou S P)
文摘We discuss the relations among the best approximation En(f) and the Fourier coeffcients of a function, f(n) ∈ C,n = 0,±1,±2,..., under the conditions that {f (n)}∞n=0 ∈ MVBVS* and {f (n) + f(n)}∞n=0 ∈ MVBVS*, where MVBVS* is the class of the so-called Strong Mean Value Bounded Variation Sequences.
基金supported by the Natural Science Foundation of Guangdong Province(2021A1515010058)supported by the Youth Innovation Foundation of Shenzhen Polytechnic University(6024310023K)。
文摘The main purpose of this paper is to investigate the univalence of normalized polyharmonic mappings with bounded length distortions in the unit disk.We first establish the coefficient estimates for polyharmonic mappings with bounded length distortions.Then,using these results,we establish five Landau-type theorems for subclasses of polyharmonic mappings F and L(F),where F has bounded length distortion and L is a differential operator.
基金Project supported by the Natural Science Foundation of Jiangxi Province (No. 0450035).
文摘A closed but approximate formula of Green’s function for an arbitrary aggregate of cubic crystallites is given to derive the e?ective elastic sti?ness tensor of the polycrystal. This formula, which includes three elastic constants of single cubic crystal and ?ve texture coe?cients, accounts for the e?ects of the orientation distribution function (ODF) up to terms linear in the tex- ture coe?cients. Thus it is expected that our formula would be applicable to arbitrary aggregates with weak texture or to materials such as aluminum whose single crystal has weak anisotropy. Three examples are presented to compare predictions from our formula with those from Nishioka and Lothe’s formula and Synge’s contour integral through numerical integration. As an applica- tion of Green’s function, we brie?y describe the procedure of deriving the e?ective elastic sti?ness tensor for an orthorhombic aggregate of cubic crystallites. The comparison of the computational results given by the ?nite element method and our e?ective elastic sti?ness tensor is made by an example.
文摘The stress-strain-resistance relations of the Fe-Mn-Si alloys with different Si content have been investigated by measuring strain (ε) and resistance (△ R/R) upon tension synchronously. The results show that the strum induced γ→ε martensitic transfor- mation increases the strain sensitivity coeffcient of resistance (K) for the Fe-Mn-Si alloys in plastic region. There is a critical strum where dσ/dε becomes a constant value. Si increases the critical strum. A correlation between the critical strain and shape memory effect (SME) in the Fe-Mn-Si alloys is suggested.
文摘The parameter estimation and the coefficient of contamination for the regression models with repeated measures are studied when its response variables are contaminated by another random variable sequence.Under the suitable conditions it is proved that the estimators which are established in the paper are strongly consistent estimators.
基金financial supported by the National High Technology Research and Development Program of China (863 Program 2011AA05A204)
文摘The equilibrium solubilities,volumetric gas-liquid mass transfer coefficients kLa of H_2 and CO were measured as functions of temperature(298―513 K),pressure(1―3 MPa),superficial gas velocity(0.5―3 cm/s) and solid volume fraction(5%―25%) in liquid paraffin/iron-based catalyst slurry bubble column reactor.The volumetric mass transfer coefficients kLa were obtained by measuring the dissolution rate of H_2 and CO.The influences of the operation conditions,such as pressure,temperature,superficial gas velocity and catalyst concentration on kLa,were investigated.Two empirical correlations were proposed to predict kLa values of H_2 and CO in liquid paraffin/solid particles slurry bubble column reactor.The results showed that the equilibrium solubilities of H-2 and CO increased with an increasing temperature and pressure,and the solubility of CO was greater than that for H_2.It was found that the equilibrium solubility can be expressed by Henry's law.The volumetric mass transfer coefficients of H_2 and CO were of the same order of magnitude,and increased with the increase of pressure,temperature and superficial gas velocity.The presence of solid particles decreased kLa values of both H_2 and CO.
文摘Expressing the excess partial molar free energies and integral excess free energy as poly- nome of the composition,then the parameters in the expression of excess partial molar free energy of C were evaluated based on:the excess partial free energy of C in C-Fe bi- nary alloy:the integral excess free energy of Fe-X binary alloy:the C saturation curve and the iso-activity curve of C (α_c=0.025) in the ternary system.Then the activity coefficient of X was evaluated with the so-called “I-D” method,by which the component activities of every element in the whole molten ternary alloy can be evaluated,and the results are in good agreement with literature data based on experiment.
文摘We define new integral operators on the Haydy space similar to Szeg<span style="white-space:nowrap;"><span style="white-space:nowrap;">ö<span style="font-family:Verdana;"> projection. We show that these operators map from <span style="font-family:Verdana;">H<sup><i style="white-space:normal;"><span style="font-family:Verdana;">p</sup><span style="font-family:Verdana;"> <span style="font-family:Verdana;">to <span style="font-family:Verdana;">H<span style="font-family:Verdana;"><sup><span style="white-space:normal;font-family:Verdana;">2 </sup><span style="font-family:Verdana;">for some 1 <span style="font-family:Verdana;">≤ <span style="font-family:Verdana;">p < <span style="font-family:Verdana;">2, where the range of <span style="font-family:Verdana;">p <span style="font-family:CMR10;"><span style="font-family:Verdana;">is depending on a growth condition. To prove that, we generalize the Hausdorff-Young Theorem to multi-dimensional case.
基金supported by the National Natural Science Foundation of China (grant numbers 42071063, 32371872)。
文摘Tree allometric models based on height(H)and diameter(D)are the most commonly used method to estimate forest biomass.Environments and stand characteristics are recognized to affect tree allometries.However,few studies have considered to incorporate these effects into allometric models,which restricts the use of these models in a wide domain.Adopting the power-law function Y=aG^(b) as a basic model where Y is either tree height or biomass and the corresponding G is tree diameter D at breast height or D^(2)H,we developed a two-step approximation procedure to quantify the effects of environments and stand characteristics on allometric coeffcients a and b for Cunninghamia lanceolata and Pinus forest in China.Results show that most of the allometric coeffcients are dependent on stand characteristics for C.lanceolata forest,and on mean annual temperature,stand age and latitude for Pinus forest.The allometric models via the two-step approximation Y=f(α+α_(j)x_(j))G^(f(β+βixi))(x_(j) or x_(i) are key drivers associated with environments and stand characteristics.α,αj,βandβi are regression coeffcients)considerably improved the accuracy of tree height and biomass estimation.Compared to the basic model,the second approximation models signifcantly reduced the mean absolute bias between the observed and computed values by 25%-34%for C.lanceolata and by 21%-26%for Pinus forest,respectively.Our results highlight the necessity of incorporating environments and stand characteristics into the allometric models and provide a universal method to accurately estimate H-D-based tree biomass across a wider domain.
基金supported by National Natural Science Foundation of China (Grant No. 10571164)Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20050358052)+1 种基金the Jiangxi Provincial Natural Science Foundation of China (Grant No. 2007GZS0177)Specialized Research Fund for the Doctoral Program of Jiangxi Normal University
文摘Let X be a complex Banach space with norm · , B be the unit ball in X, Dn be the unit polydisc in Cn. In this paper, we introduce a class of holomorphic mappings Mg on B or Dn. Let f(x) be a normalized locally biholomorphic mapping on B such that (Df(x))-1f(x) ∈ Mg and f(x) - x has a zero of order k + 1 at x = 0. We obtain coeffcient estimates for f(x). These results unify and generalize many known results.
基金ANR-17-CE40-0029 of the French National Research Agency ANR(project MultiOnde).
文摘This paper concerns the reconstruction of a scalar coefficient of a second-order elliptic equation in divergence form posed on a bounded domain from internal data.This problem finds applications in multi-wave imaging,greedy methods to approximate parameter-dependent elliptic problems,and image treatment with partial differential equations.We first show that the inverse problem for smooth coefficients can be rewritten as a linear transport equation.Assuming that the coefficient is known near the boundary,we study the well-posedness of associated transport equation as well as its numerical resolution using discontinuous Galerkin method.We propose a regularized transport equation that allow us to derive rigorous convergence rates of the numerical method in terms of the order of the polynomial approximation as well as the regularization parameter.We finally provide numerical examples for the inversion assuming a lower regularity of the coefficient,and using synthetic data.
文摘A dynamical statistical model is used to analyze the experimental shape isomer yields data in the reaction d＋240Pu at E=20–29 MeV.The possibility of determining the nuclear dissipation is discussed.Comparison of the experimental data with the calculations leads to a value of the reduced dissipation coeffcient β=0.45×1021 s-1 for the Am isotopes.
文摘Ethanol-water binary mixtures with 7 different mole fractions of ethanol ranging from 0 to 1 were adopted as testing liquids in the experiment. The vertical heating tube was inserted in porous matrix composed of five well sorted glass beads whose diameters range from 0.5 to 4.3 mm. Due to the effect of composition, the trend of combination of vapor bubbles was reduced, resulting in the increase of peak heat flux of binary mixture. With the increase of ethanol mole fraction, 0.5 mm diameter bead had lower value of peak heat flux, while for pure liquid the critical state is difficult to appear. With given diameter of glass bead, there existed an optimum value of mole fraction of ethanol, which was decreased with the increase of bead diameter. A dimensionless heat transfer coefficient was predicted through the introduction of a dimensionless parameter of porous matrix, which agreed with the experimental results satisfactorily.
