Regularization inversion uses constraints and a regularization factor to solve ill- posed inversion problems in geophysics. The choice of the regularization factor and of the initial model is critical in regularizatio...Regularization inversion uses constraints and a regularization factor to solve ill- posed inversion problems in geophysics. The choice of the regularization factor and of the initial model is critical in regularization inversion. To deal with these problems, we propose a multiobjective particle swarm inversion （MOPSOI） algorithm to simultaneously minimize the data misfit and model constraints, and obtain a multiobjective inversion solution set without the gradient information of the objective function and the regularization factor. We then choose the optimum solution from the solution set based on the trade-off between data misfit and constraints that substitute for the regularization factor. The inversion of synthetic two-dimensional magnetic data suggests that the MOPSOI algorithm can obtain as many feasible solutions as possible; thus, deeper insights of the inversion process can be gained and more reasonable solutions can be obtained by balancing the data misfit and constraints. The proposed MOPSOI algorithm can deal with the problems of choosing the right regularization factor and the initial model.展开更多
To get the quantitive value of abnormal biological tissues, an inverse algorithm about the Young＇s modulus based on the boundary extraction and the image registration technologies is proposed. With the known displace...To get the quantitive value of abnormal biological tissues, an inverse algorithm about the Young＇s modulus based on the boundary extraction and the image registration technologies is proposed. With the known displacements of boundary tissues and the force distribution, the Young＇s modulus is calculated by constructing the unit system and the inverse finite element method （IFEM）. Then a tough range of the modulus for the whole tissue is estimated referring the value obtained before. The improved particle swarm optimizer （PSO） method is adopted to calculate the whole Yong＇s modulus distribution. The presented algorithm overcomes some limitations in other Young＇s modulus reconstruction methods and relaxes the displacements and force boundary condition requirements. The repetitious numerical simulation shows that errors in boundary displacement are not very sensitive to the estimation of next process; a final feasible solution is obtained by the improved PSO method which is close to the theoretical values obtained during searching in an extensive range.展开更多
Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization （HDS） were synthesized by two different phosphorus sources, in which the surface of Ni2P catalysts were modified by air instead of b...Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization （HDS） were synthesized by two different phosphorus sources, in which the surface of Ni2P catalysts were modified by air instead of being passivated by O2/N2 mixture. In addition, the catalysts need not be activated with flowing H2 （30 ml·min^-1） at 500℃ for 2 h prior to reaction as traditional method. X-ray diffraction （XRD）, X-ray photoelectro spectroscopy （XPS）, N2-adsorption specific surface area measurements and CO chemisorption were used to characterize the resulting catalysts. The effect of modification with air on the surface of the catalysts for HDS performance was investigated. Results showed that the surface modification with air can promote the formation of smaller Ni2P particles and more active Ni sites on surface of catalysts. At 3.0 MPa and 613 K, the dibenzothiophene （DBT） conversion of the catalysts modified with air was 98.7%, which was 7.1% higher than that of catalyst passivated by O2/N2 mixture. The higher activities of Ni2P（x）/M41-O catalysts can be attributed to the smaller Ni2P particles sizes and the increased hydrogen dissociation activity due to the surface modification.展开更多
The recent progresses on the wobbling motion are briefly introduced.So far 17 wobbling candidates have been reported in odd-A and even-even nuclei that spread over A≈100,130,160 and 190 mass regions.The two-quasipart...The recent progresses on the wobbling motion are briefly introduced.So far 17 wobbling candidates have been reported in odd-A and even-even nuclei that spread over A≈100,130,160 and 190 mass regions.The two-quasiparticle configuration wobbling in ^(130)Ba and the wobbling motion in a triaxial rotor are taken as examples in this paper to show the wobbling motion in even-even nuclei.For the ^(130)Ba,the wobbling are investigated based on the combination of the covariant density functional theory(CDFT)and the particle rotor model(PRM).The CDFT provides crucial information on the configuration and deformation parameters of observed bands,serving as input for PRM calculations.The corresponding experimental energy spectra and electromagnetic transition probabilities are reproduced.An analysis of the angular momentum geometry reveals the enhanced stability of transverse wobbling of a two-quasiparticle configuration compared to a single-quasiparticle one.For the triaxial rotor,the time evolution of wobbling motion is explored through the solution of Euler equations.This investigation yields valuable insights into the evolution of orientation angles(φ and θ)and angular momentum components.Notably,the study reveals that low-energy states of a triaxial rotor predominantly exhibit wobbling motion around the intermediate axis.Moreover,an increase in excitation energy corresponds to a prolonged period of intermediate axis wobbling motion.Conversely,a contrasting trend is observed in the case of long axis wobbling,where an increase in excitation energy leads to a decrease in the wobbling period.展开更多
Effects of agglomerates on the densification behavior and microstructural evolution during solid-state sintering of a cube of copper particles have been studied with discrete element method (DEM).It is found that the ...Effects of agglomerates on the densification behavior and microstructural evolution during solid-state sintering of a cube of copper particles have been studied with discrete element method (DEM).It is found that the densification of the sintering system decreases as the volume fraction of agglomerates increases.At a given volume fraction of agglomerates,the smaller the size of agglomerates,the poorer the densification and more inhomogeneous the compact is.The morphology and distribution of agglomerates have negligible effects on the densification,especially for the case with a low volume fraction of agglomerates.Agglomerates with a smaller average coordination number would have more restriction on the densification of sintering bodies.To our best knowledge,it is the first time to study the effect of agglomerates on sintering behavior using DEM.This study should be useful for further investigations of the effect of various inhomogeneities of microstructure on the complex sintering process by DEM.展开更多
In this paper,we study the effect of spontaneously generated coherence(SGC) on transient evolution of gain without inversion(GWI) in a Doppler broadened quasi Λ-type four-level atomic system.It is shown that transien...In this paper,we study the effect of spontaneously generated coherence(SGC) on transient evolution of gain without inversion(GWI) in a Doppler broadened quasi Λ-type four-level atomic system.It is shown that transient evolution of GWI is very sensitive to the variation of SGC strength,and the transient maximum value and steady value of GWI both increase with SGC strength increasing.The transient and steady values of GWI with SGC are much larger than those without SGC.When Doppler broadening is present,the transient maximum value and steady value of GWI first increase and then decrease with Doppler broadening width(D) increasing,and the value of D which corresponds to the maximum transient GWI is different from that corresponding to the maximum steady GWI.The time needed for reaching the steady GWI increases with D increasing.The steady GWI,which is larger than that without Doppler broadening(D = 0),can be obtained by choosing appropriate D and SGC strength.展开更多
We investigate the time evolution of quantum correlations of a hybrid qubit-qutrit system under the classical Ornstein-Uhlenbeck(OU) noise. Here we consider two different one-parameter families of qubit-qutrit states ...We investigate the time evolution of quantum correlations of a hybrid qubit-qutrit system under the classical Ornstein-Uhlenbeck(OU) noise. Here we consider two different one-parameter families of qubit-qutrit states which independently interact with the non-Markovian reservoirs. A comparison with the Markovian dynamics reveals that for the same set of initial condition parameters, the non-Markovian behavior of the environment plays an important role in the enhancement of the survival time of quantum correlations. In addition, it is observed that the non-Markovian strength(γ/Γ) has a positive impact on the correlations time. For the initial separable states it is found that there is a finite time interval in which the geometric quantum discord is frozen despite the presence of a noisy environment and that interval can be further prolonged by using the non-Markovian property. Moreover, its decay can be significantly delayed.展开更多
基金supported by the Natural Science Foundation of China(No.61273179)Department of Education,Science and Technology Research Project of Hubei Province of China(No.D20131206,No.20141304)
文摘Regularization inversion uses constraints and a regularization factor to solve ill- posed inversion problems in geophysics. The choice of the regularization factor and of the initial model is critical in regularization inversion. To deal with these problems, we propose a multiobjective particle swarm inversion （MOPSOI） algorithm to simultaneously minimize the data misfit and model constraints, and obtain a multiobjective inversion solution set without the gradient information of the objective function and the regularization factor. We then choose the optimum solution from the solution set based on the trade-off between data misfit and constraints that substitute for the regularization factor. The inversion of synthetic two-dimensional magnetic data suggests that the MOPSOI algorithm can obtain as many feasible solutions as possible; thus, deeper insights of the inversion process can be gained and more reasonable solutions can be obtained by balancing the data misfit and constraints. The proposed MOPSOI algorithm can deal with the problems of choosing the right regularization factor and the initial model.
文摘To get the quantitive value of abnormal biological tissues, an inverse algorithm about the Young＇s modulus based on the boundary extraction and the image registration technologies is proposed. With the known displacements of boundary tissues and the force distribution, the Young＇s modulus is calculated by constructing the unit system and the inverse finite element method （IFEM）. Then a tough range of the modulus for the whole tissue is estimated referring the value obtained before. The improved particle swarm optimizer （PSO） method is adopted to calculate the whole Yong＇s modulus distribution. The presented algorithm overcomes some limitations in other Young＇s modulus reconstruction methods and relaxes the displacements and force boundary condition requirements. The repetitious numerical simulation shows that errors in boundary displacement are not very sensitive to the estimation of next process; a final feasible solution is obtained by the improved PSO method which is close to the theoretical values obtained during searching in an extensive range.
基金Supported by the National Natural Science Foundation of China(21276048)the Project of Education Department of Heilongjiang Province,China(12541060)the Graduate Innovation Project of Northeast Petroleum University,China(YJSCX2016-019NEPU)
文摘Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization （HDS） were synthesized by two different phosphorus sources, in which the surface of Ni2P catalysts were modified by air instead of being passivated by O2/N2 mixture. In addition, the catalysts need not be activated with flowing H2 （30 ml·min^-1） at 500℃ for 2 h prior to reaction as traditional method. X-ray diffraction （XRD）, X-ray photoelectro spectroscopy （XPS）, N2-adsorption specific surface area measurements and CO chemisorption were used to characterize the resulting catalysts. The effect of modification with air on the surface of the catalysts for HDS performance was investigated. Results showed that the surface modification with air can promote the formation of smaller Ni2P particles and more active Ni sites on surface of catalysts. At 3.0 MPa and 613 K, the dibenzothiophene （DBT） conversion of the catalysts modified with air was 98.7%, which was 7.1% higher than that of catalyst passivated by O2/N2 mixture. The higher activities of Ni2P（x）/M41-O catalysts can be attributed to the smaller Ni2P particles sizes and the increased hydrogen dissociation activity due to the surface modification.
文摘The recent progresses on the wobbling motion are briefly introduced.So far 17 wobbling candidates have been reported in odd-A and even-even nuclei that spread over A≈100,130,160 and 190 mass regions.The two-quasiparticle configuration wobbling in ^(130)Ba and the wobbling motion in a triaxial rotor are taken as examples in this paper to show the wobbling motion in even-even nuclei.For the ^(130)Ba,the wobbling are investigated based on the combination of the covariant density functional theory(CDFT)and the particle rotor model(PRM).The CDFT provides crucial information on the configuration and deformation parameters of observed bands,serving as input for PRM calculations.The corresponding experimental energy spectra and electromagnetic transition probabilities are reproduced.An analysis of the angular momentum geometry reveals the enhanced stability of transverse wobbling of a two-quasiparticle configuration compared to a single-quasiparticle one.For the triaxial rotor,the time evolution of wobbling motion is explored through the solution of Euler equations.This investigation yields valuable insights into the evolution of orientation angles(φ and θ)and angular momentum components.Notably,the study reveals that low-energy states of a triaxial rotor predominantly exhibit wobbling motion around the intermediate axis.Moreover,an increase in excitation energy corresponds to a prolonged period of intermediate axis wobbling motion.Conversely,a contrasting trend is observed in the case of long axis wobbling,where an increase in excitation energy leads to a decrease in the wobbling period.
基金supported by the National Natural Science Foundation of China (Grant Nos.10972220,11021262 and 11125211)the National Basic Research Program of China (Grant No.2012CB937500)
文摘Effects of agglomerates on the densification behavior and microstructural evolution during solid-state sintering of a cube of copper particles have been studied with discrete element method (DEM).It is found that the densification of the sintering system decreases as the volume fraction of agglomerates increases.At a given volume fraction of agglomerates,the smaller the size of agglomerates,the poorer the densification and more inhomogeneous the compact is.The morphology and distribution of agglomerates have negligible effects on the densification,especially for the case with a low volume fraction of agglomerates.Agglomerates with a smaller average coordination number would have more restriction on the densification of sintering bodies.To our best knowledge,it is the first time to study the effect of agglomerates on sintering behavior using DEM.This study should be useful for further investigations of the effect of various inhomogeneities of microstructure on the complex sintering process by DEM.
基金supported by the National Natural Science Foundation of China (No.11175105)
文摘In this paper,we study the effect of spontaneously generated coherence(SGC) on transient evolution of gain without inversion(GWI) in a Doppler broadened quasi Λ-type four-level atomic system.It is shown that transient evolution of GWI is very sensitive to the variation of SGC strength,and the transient maximum value and steady value of GWI both increase with SGC strength increasing.The transient and steady values of GWI with SGC are much larger than those without SGC.When Doppler broadening is present,the transient maximum value and steady value of GWI first increase and then decrease with Doppler broadening width(D) increasing,and the value of D which corresponds to the maximum transient GWI is different from that corresponding to the maximum steady GWI.The time needed for reaching the steady GWI increases with D increasing.The steady GWI,which is larger than that without Doppler broadening(D = 0),can be obtained by choosing appropriate D and SGC strength.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11274132 and 11550110180
文摘We investigate the time evolution of quantum correlations of a hybrid qubit-qutrit system under the classical Ornstein-Uhlenbeck(OU) noise. Here we consider two different one-parameter families of qubit-qutrit states which independently interact with the non-Markovian reservoirs. A comparison with the Markovian dynamics reveals that for the same set of initial condition parameters, the non-Markovian behavior of the environment plays an important role in the enhancement of the survival time of quantum correlations. In addition, it is observed that the non-Markovian strength(γ/Γ) has a positive impact on the correlations time. For the initial separable states it is found that there is a finite time interval in which the geometric quantum discord is frozen despite the presence of a noisy environment and that interval can be further prolonged by using the non-Markovian property. Moreover, its decay can be significantly delayed.
