In this paper, we propose a compound algorithm for the image restoration. The algorithm is a convex combination of the ROF model and the LLT model with a parameter function 0. The numerical experiments demonstrate tha...In this paper, we propose a compound algorithm for the image restoration. The algorithm is a convex combination of the ROF model and the LLT model with a parameter function 0. The numerical experiments demonstrate that our compound algorithm is efficient and preserves the main advantages of the two models. In particular, the errors of the compound algorithm in L2 norm between the exact images and corresponding restored images are the smallest among the three models. For images with strong noises, the restored images of the compound algorithm are the best in the corresponding restored images. The proposed algorithm combines the fixed point method, an improved AMG method and the Krylov acceleration. It is found that the combination of these methods is efficient and robust in the image restoration.展开更多
Elliptic curve cryptography has been used in many security systems due to its small key size and high security compared with other cryptosystems. In many well-known security systems, a substitution box (S-box) is the ...Elliptic curve cryptography has been used in many security systems due to its small key size and high security compared with other cryptosystems. In many well-known security systems, a substitution box (S-box) is the only non-linear component. Recently, it has been shown that the security of a cryptosystem can be improved using dynamic S-boxes instead of a static S-box. This necessitates the construction of new secure S-boxes. We propose an efficient method to generate S-boxes that are based on a class of Mordell elliptic curves over prime fields and achieved by defining different total orders. The proposed scheme is devel-oped in such a way that for each input it outputs an S-box in linear time and constant space. Due to this property, our method takes less time and space than the existing S-box construction methods over elliptic curves. Computational results show that the pro-posed method is capable of generating cryptographically strong S-boxes with security comparable to some of the existing S-boxes constructed via different mathematical structures.展开更多
Neutron diffraction and total scattering are combined to investigate a series of single-phase 10-component compositionally complexfluorite-based oxides,[(Pr_(0.375)Nd_(0.375)Yb_(0.25))2(Ti_(0.5)Hf_(0.25)Zr_(0.25))_(2)O...Neutron diffraction and total scattering are combined to investigate a series of single-phase 10-component compositionally complexfluorite-based oxides,[(Pr_(0.375)Nd_(0.375)Yb_(0.25))2(Ti_(0.5)Hf_(0.25)Zr_(0.25))_(2)O_(7)]_(1-x)[(DyHoErNb)O_(7)]_(x),denoted as 10CCFBOxNb.A long-range order-disorder transition(ODT)occurs at x=0.81±0.01 from the ordered pyrochlore to disordered defectfluorite.In contrast to ternary oxides,this ODT occurs abruptly without an observable two-phase region;moreover,the phase stability in 10CCFBOs deviates from the well-established criteria for simpler oxides.Rietveld refinements of neutron diffraction patterns suggest that this ODT occurs via the migration of oxygen anions from the position 48f to 8a,with a smallfinal jump at the ODT;however,the 8a oxygen occupancy changes gradually(without an observable discontinuous jump).We further discover diffuse scattering in Nb-rich compositions,which suggests the presence of short-range order.Using small-box modelling,four compositions near ODT(x=0.75,0.8,0.85,and 1)can be betterfitted by C2221 weberite ordering for the local polyhedral structure at nanoscale.Interestingly,10CCFBO_(0.75)Nb and 10CCFBO_(0.8)Nb possess both long-range pyrochlore order and short-range weberite-type order,which can be understood from severe local distortion of the pyrochlore polyhedral structure.Thus,weberite-type short-range order emerges before the ODT,coexisting and interacting with long-range pyrochlore order.After the ODT,the long-range pyrochlore order vanishes but the short-range weberite-type order persists in the long-range disordered defectfluorite structure.Notably,a drop in the thermal conductivity coincides with emergence of the short-range order,instead of the long-range ODT.展开更多
In this paper,we propose a fast proximity point algorithm and apply it to total variation(TV)based image restoration.The novel method is derived from the idea of establishing a general proximity point operator framewo...In this paper,we propose a fast proximity point algorithm and apply it to total variation(TV)based image restoration.The novel method is derived from the idea of establishing a general proximity point operator framework based on which new first-order schemes for total variation(TV)based image restoration have been proposed.Many current algorithms for TV-based image restoration,such as Chambolle’s projection algorithm,the split Bregman algorithm,the Berm´udez-Moreno algorithm,the Jia-Zhao denoising algorithm,and the fixed point algorithm,can be viewed as special cases of the new first-order schemes.Moreover,the convergence of the new algorithm has been analyzed at length.Finally,we make comparisons with the split Bregman algorithm which is one of the best algorithms for solving TV-based image restoration at present.Numerical experiments illustrate the efficiency of the proposed algorithms.展开更多
The effectiveness,viability and feasibility of applying Fenton reactants in treating soil contaminated with automatic gas oil(AGO)was investigated ex-situ.Soil was simulated to achieve 10%contamination using AGO(diese...The effectiveness,viability and feasibility of applying Fenton reactants in treating soil contaminated with automatic gas oil(AGO)was investigated ex-situ.Soil was simulated to achieve 10%contamination using AGO(diesel)as the primary contaminant.Physicochemical properties and heavy metal contents were characterized using standard analytical methods,while total petroleum hydrocarbon(TPH)content was determined by molecular spectroscopy.An investigation of the soil physicochemical properties shows severe impact of the contaminant on pH,conductivity,phosphorus and(TPH)content.The optimum concentration of Fenton reactants determined from the optimization study was found to be 350,000 ppm H2O2 and 600 ppm FeSO4 at optimum room temperature range of 27e30C and optimum pH of 4.7.The highly exothermic Fenton oxidation treatment resulted in significant decrease in TPH content by 87.6%after 6 h of periodic monitoring;breaking down the hydrocarbons into non-toxic environmental friendly products.Kinetics analysis and evaluation shows pseudo-first order mechanism for the Fenton treatment with a calculated rate constant of 0.226 h-1 and half life of 3 h 4 min.The Fenton method is found to be very effective and efficient not only for the removal of the diesel contaminant,but also for the restoration of lost physicochemical properties occasioned by the effect of the contaminant.The environmental friendliness and fast response time towards effective clean up gives the technique a cutting edge advantage over other conventional methods.It therefore presents potentials for remediation experts in outright applications on real field challenges.展开更多
We proved that there exists a family of complete oriented minimal surfaces in R3 with finite total curvature-4nπ,each of which has 0 genus and two ends,and both of the ends have winding order n,where n ∈ N,and discu...We proved that there exists a family of complete oriented minimal surfaces in R3 with finite total curvature-4nπ,each of which has 0 genus and two ends,and both of the ends have winding order n,where n ∈ N,and discussed the symmetric property for special parameters.展开更多
In the present paper, we introduce Szasz-Durrmeyer-Bezier operators M.,.(f,x) , which generalize the Szasz-Durrmeyer operators. Here we obtain an estimate on the rate of convergence of Mn,a(f,x) for functions of bound...In the present paper, we introduce Szasz-Durrmeyer-Bezier operators M.,.(f,x) , which generalize the Szasz-Durrmeyer operators. Here we obtain an estimate on the rate of convergence of Mn,a(f,x) for functions of bounded variation. Our result extends and improves that of Sahai and Prasad and Gupta and Pant.展开更多
基金suppprt from NSFC of China,Singapore NTU project SUG 20/07,MOE Grant T207B2202NRF2007IDMIDM002-010
文摘In this paper, we propose a compound algorithm for the image restoration. The algorithm is a convex combination of the ROF model and the LLT model with a parameter function 0. The numerical experiments demonstrate that our compound algorithm is efficient and preserves the main advantages of the two models. In particular, the errors of the compound algorithm in L2 norm between the exact images and corresponding restored images are the smallest among the three models. For images with strong noises, the restored images of the compound algorithm are the best in the corresponding restored images. The proposed algorithm combines the fixed point method, an improved AMG method and the Krylov acceleration. It is found that the combination of these methods is efficient and robust in the image restoration.
基金Project supported by the JSPS KAKENHI(No.18J23484)
文摘Elliptic curve cryptography has been used in many security systems due to its small key size and high security compared with other cryptosystems. In many well-known security systems, a substitution box (S-box) is the only non-linear component. Recently, it has been shown that the security of a cryptosystem can be improved using dynamic S-boxes instead of a static S-box. This necessitates the construction of new secure S-boxes. We propose an efficient method to generate S-boxes that are based on a class of Mordell elliptic curves over prime fields and achieved by defining different total orders. The proposed scheme is devel-oped in such a way that for each input it outputs an S-box in linear time and constant space. Due to this property, our method takes less time and space than the existing S-box construction methods over elliptic curves. Computational results show that the pro-posed method is capable of generating cryptographically strong S-boxes with security comparable to some of the existing S-boxes constructed via different mathematical structures.
基金supported by the National Science Foundation(NSF)via Grant No.DMR-2026193.A portion of this research used resources at the Spallation Neutron Source,a DOE Office of Science User Facility operated by the ORNL.The STEM work was performed at the Irvine Materials Research Institute(IMRI).
文摘Neutron diffraction and total scattering are combined to investigate a series of single-phase 10-component compositionally complexfluorite-based oxides,[(Pr_(0.375)Nd_(0.375)Yb_(0.25))2(Ti_(0.5)Hf_(0.25)Zr_(0.25))_(2)O_(7)]_(1-x)[(DyHoErNb)O_(7)]_(x),denoted as 10CCFBOxNb.A long-range order-disorder transition(ODT)occurs at x=0.81±0.01 from the ordered pyrochlore to disordered defectfluorite.In contrast to ternary oxides,this ODT occurs abruptly without an observable two-phase region;moreover,the phase stability in 10CCFBOs deviates from the well-established criteria for simpler oxides.Rietveld refinements of neutron diffraction patterns suggest that this ODT occurs via the migration of oxygen anions from the position 48f to 8a,with a smallfinal jump at the ODT;however,the 8a oxygen occupancy changes gradually(without an observable discontinuous jump).We further discover diffuse scattering in Nb-rich compositions,which suggests the presence of short-range order.Using small-box modelling,four compositions near ODT(x=0.75,0.8,0.85,and 1)can be betterfitted by C2221 weberite ordering for the local polyhedral structure at nanoscale.Interestingly,10CCFBO_(0.75)Nb and 10CCFBO_(0.8)Nb possess both long-range pyrochlore order and short-range weberite-type order,which can be understood from severe local distortion of the pyrochlore polyhedral structure.Thus,weberite-type short-range order emerges before the ODT,coexisting and interacting with long-range pyrochlore order.After the ODT,the long-range pyrochlore order vanishes but the short-range weberite-type order persists in the long-range disordered defectfluorite structure.Notably,a drop in the thermal conductivity coincides with emergence of the short-range order,instead of the long-range ODT.
基金the National Science Foundation of China under grants(No.61271014)Specialized Research Fund for the Doctoral Program of Higher Education(20124301110003)the Graduated Students Innovation Fund of Hunan Province(CX2012B238).
文摘In this paper,we propose a fast proximity point algorithm and apply it to total variation(TV)based image restoration.The novel method is derived from the idea of establishing a general proximity point operator framework based on which new first-order schemes for total variation(TV)based image restoration have been proposed.Many current algorithms for TV-based image restoration,such as Chambolle’s projection algorithm,the split Bregman algorithm,the Berm´udez-Moreno algorithm,the Jia-Zhao denoising algorithm,and the fixed point algorithm,can be viewed as special cases of the new first-order schemes.Moreover,the convergence of the new algorithm has been analyzed at length.Finally,we make comparisons with the split Bregman algorithm which is one of the best algorithms for solving TV-based image restoration at present.Numerical experiments illustrate the efficiency of the proposed algorithms.
文摘The effectiveness,viability and feasibility of applying Fenton reactants in treating soil contaminated with automatic gas oil(AGO)was investigated ex-situ.Soil was simulated to achieve 10%contamination using AGO(diesel)as the primary contaminant.Physicochemical properties and heavy metal contents were characterized using standard analytical methods,while total petroleum hydrocarbon(TPH)content was determined by molecular spectroscopy.An investigation of the soil physicochemical properties shows severe impact of the contaminant on pH,conductivity,phosphorus and(TPH)content.The optimum concentration of Fenton reactants determined from the optimization study was found to be 350,000 ppm H2O2 and 600 ppm FeSO4 at optimum room temperature range of 27e30C and optimum pH of 4.7.The highly exothermic Fenton oxidation treatment resulted in significant decrease in TPH content by 87.6%after 6 h of periodic monitoring;breaking down the hydrocarbons into non-toxic environmental friendly products.Kinetics analysis and evaluation shows pseudo-first order mechanism for the Fenton treatment with a calculated rate constant of 0.226 h-1 and half life of 3 h 4 min.The Fenton method is found to be very effective and efficient not only for the removal of the diesel contaminant,but also for the restoration of lost physicochemical properties occasioned by the effect of the contaminant.The environmental friendliness and fast response time towards effective clean up gives the technique a cutting edge advantage over other conventional methods.It therefore presents potentials for remediation experts in outright applications on real field challenges.
基金Supported by the Specific Research Fund of the Doctoral Program of Higher Education of China (Grant No.20050141011)the MATH+X Project offered by Dalian University of Technology (Grant No.MXDUT073005)the Science Fund of Dalian University of Technology
文摘We proved that there exists a family of complete oriented minimal surfaces in R3 with finite total curvature-4nπ,each of which has 0 genus and two ends,and both of the ends have winding order n,where n ∈ N,and discussed the symmetric property for special parameters.
文摘In the present paper, we introduce Szasz-Durrmeyer-Bezier operators M.,.(f,x) , which generalize the Szasz-Durrmeyer operators. Here we obtain an estimate on the rate of convergence of Mn,a(f,x) for functions of bounded variation. Our result extends and improves that of Sahai and Prasad and Gupta and Pant.
