Hemingway established a well-known literary theory - iceberg principle.He said he always attempted to create his literary works according to this principle.In his opinion,if a prose writer has a pretty clear idea of w...Hemingway established a well-known literary theory - iceberg principle.He said he always attempted to create his literary works according to this principle.In his opinion,if a prose writer has a pretty clear idea of what he writes about,then he can omit the things he knows,and the readers will strongly feel that what the writer has omitted seems to have been written as long as what he writes is authentic.Hemingway himself once said,"The dignity of movement of an iceberg is due to only one eighth of it being above water."Here,one eighth refers to the information given by the author,and the rest refers to the unwrit ten information that can be acquired in readers'imagination on the basis of the one eighth.The Killers is a good example of Hemingway's iceberg principle.This essay will analyse the characters in it to show how the principle was used in this short story.With no doubt the iceberg principle leaves a large space for the readers to imagine and better understand Hemingway's works.展开更多
By using the properties of w-distances and Gerstewitz＇s functions, we first give a vectorial Takahashi＇s nonconvex minimization theorem with a w-distance. From this, we deduce a general vectorial Ekeland＇s variatio...By using the properties of w-distances and Gerstewitz＇s functions, we first give a vectorial Takahashi＇s nonconvex minimization theorem with a w-distance. From this, we deduce a general vectorial Ekeland＇s variational principle, where the objective function is from a complete metric space into a pre-ordered topological vector space and the perturbation contains a w-distance and a non-decreasing function of the objective function value. From the general vectorial variational principle, we deduce a vectorial Caristfs fixed point theorem with a w-distance. Finally we show that the above three theorems are equivalent to each other. The related known results are generalized and improved. In particular, some conditions in the theorems of [Y. Araya, Ekeland＇s variational principle and its equivalent theorems in vector optimization, J. Math. Anal. Appl. 346（2008）, 9-16] are weakened or even completely relieved.展开更多
This paper summarized the recent development on Herglotz’s generalized variational principle and its symmetries and conserved quantities for nonconservative dynamical systems.Taking Lagrangian mechanics,Hamiltonian m...This paper summarized the recent development on Herglotz’s generalized variational principle and its symmetries and conserved quantities for nonconservative dynamical systems.Taking Lagrangian mechanics,Hamiltonian mechanics and Birkhoffian mechanics as three research frames,we introduce Herglotz’s generalized variational principle,dynamical equations of Herglotz type,Noether symmetry and conserved quantities,and their generalization to time-delay dynamics,fractional dynamics and time-scale dynamics,and put forward some problems as suggestions for future research.展开更多
The dynamical and physical behavior of a complex system can be more accurately described by using the fractional model.With the successful use of fractional calculus in many areas of science and engineering,it is nece...The dynamical and physical behavior of a complex system can be more accurately described by using the fractional model.With the successful use of fractional calculus in many areas of science and engineering,it is necessary to extend the classical theories and methods of analytical mechanics to the fractional dynamic system.Birkhoffian mechanics is a natural generalization of Hamiltonian mechanics,and its core is the Pfaff-Birkhoff principle and Birkhoff′s equations.The study on the Birkhoffian mechanics is an important developmental direction of modern analytical mechanics.Here,the fractional Pfaff-Birkhoff variational problem is presented and studied.The definitions of fractional derivatives,the formulae for integration by parts and some other preliminaries are firstly given.Secondly,the fractional Pfaff-Birkhoff principle and the fractional Birkhoff′s equations in terms of RieszRiemann-Liouville fractional derivatives and Riesz-Caputo fractional derivatives are presented respectively.Finally,an example is given to illustrate the application of the results.展开更多
In this paper, we introduce a concept of quasi C-lower semicontinuity for setvalued mapping and provide a vector version of Ekeland＇s theorem related to set-valued vector equilibrium problems. As applications, we der...In this paper, we introduce a concept of quasi C-lower semicontinuity for setvalued mapping and provide a vector version of Ekeland＇s theorem related to set-valued vector equilibrium problems. As applications, we derive an existence theorem of weakly efficient solution for set-valued vector equilibrium problems without the assumption of convexity of the constraint set and the assumptions of convexity and monotonicity of the set-valued mapping. We also obtain an existence theorem of ε-approximate solution for set-valued vector equilibrium problems without the assumptions of compactness and convexity of the constraint set.展开更多
This article obtains an explicit expression of the heat kernels on H-type groups and then follow the estimate of heat kernels to deduce the Hardy＇s uncertainty principle on the nilpotent Lie groups.
Variational principles are constructed using the semi-inverse method for two kinds of extended Korteweg-de Vries （KdV） equations, which can be regarded as simple models of the nonlinear oceanic internal waves and at...Variational principles are constructed using the semi-inverse method for two kinds of extended Korteweg-de Vries （KdV） equations, which can be regarded as simple models of the nonlinear oceanic internal waves and atmospheric long waves, respectively. The obtained variational principles have also been proved to be correct.展开更多
The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the...The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the studies the alkali metals were treated as dopants. Several recent studies have showed that the alkali metals may not only act as dopants but also form secondary phases in the absorber layer or on the surfaces of the films. Using the first-principles calculations, we screened out the most probable secondary phases of Na and K in CIGS and CZTSSe, and studied their electronic structures and optical properties. We found that all these alkali chalcogenide compounds have larger band gaps and lower VBM levels than CIGS and CZTSSe, because the existence of strong p-d coupling in CIS and CZTS pushes the valence band maximum （VBM） level up and reduces the band-gaps, while there is no such p-d coupling in these alkali chalcogenides. This band alignment repels the photo-generated holes from the secondary phases and prevents the electron-hole recombination. Moreover, the study on the optical properties of the secondary phases showed that the absorption coefficients of these alkali chalcogenides are much lower than those of CIGS and CZTSSe in the energy range of 0-3.4eV, which means that the alkali chalcogenides may not influence the absorption of solar light. Since the alkali metal dopants can passivate the grain boundaries and increase the hole carrier concentration, and meanwhile their related secondary phases have innocuous effect on the optical absorption and band alignment, we can understand why the alkali metal dopants can improve the CIGS and CZTSSe solar cell performance.展开更多
The structural,electronic,mechanical properties,and frequency-dependent refractive indexes of GaSe1-xSx（x=0,0.25,and 1） are studied by using the first-principles pseudopotential method within density functional theo...The structural,electronic,mechanical properties,and frequency-dependent refractive indexes of GaSe1-xSx（x=0,0.25,and 1） are studied by using the first-principles pseudopotential method within density functional theory.The calculated results demonstrate the relationships between intralayer structure and elastic modulus in GaSe1-xSx（x=0,0.25,and 1）.Doping of ε-GaSe with S strengthens the Ga-X bonds and increases its elastic moduli of C（11） and C（66）.Born effective charge analysis provides an explanation for the modification of cleavage properties about the doping of e-GaSe with S.The calculated results of band gaps suggest that the distance between intralayer atom and substitution of S（Se）,rather than interlayer force,is a key factor influencing the electronic exciton energy of the layer semiconductor.The calculated refractive indexes indicate that the doping of ε-GaSe with S reduces its refractive index and increases its birefringence.展开更多
Eugene O’Neill,one of the essential writers of the 20th century,was hailed as the“American Shakespeare.”He enjoyed a high reputation in America owing to his special writing techniques.Long Day’s Journey into Night...Eugene O’Neill,one of the essential writers of the 20th century,was hailed as the“American Shakespeare.”He enjoyed a high reputation in America owing to his special writing techniques.Long Day’s Journey into Night was his last play,which was an autobiographical play to some extent,and founded on his own authentic experience.The play told the story of an Irish immigrant family’s daily life from day to night.Among the studies at home and abroad,many discuss this play from a psychological perspective and Feminist perspective.The article,instead,gives an interpretation of this play according to Cooperative Principle.Through the analysis of their conversations,it points out what principles their communications violated so as to understand the implied meaning of their conversations.The thesis tries to study the conversations between Mary and other family members,and then demonstrate that Mary is the most tragic person in the family.展开更多
This paper discusses a class of vertex-transitive digraphs.It is shown that these digraphs are rational and can be decomposed into Hamiltonian dicycles.
This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dyn...This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and E1-Nabulsi-Hamilton＇s canoni- cal equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of E1-Nabulsi-Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of E1-Nabulsi-Hamilton action under the infinitesimal transformations of the group. Fi- nally, Noether＇s theorems for the non-conservative Hamilton system under the E1-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system.展开更多
In this paper, we present the fractional Hamilton＇s canonical equations and the fractional non-Noether symmetry of Hamilton systems by the conformable fractional derivative. First/y, the exchanging relationship betwe...In this paper, we present the fractional Hamilton＇s canonical equations and the fractional non-Noether symmetry of Hamilton systems by the conformable fractional derivative. First/y, the exchanging relationship between isochronous variation and fractional derivatives, and the fractional Hamilton principle of the system under this fractional derivative are proposed. Secondly, the fractional Hamilton＇s canonical equations of Hamilton systems based on the Hamilton principle are established. Thirdly, the fractional non-Noether symmetries, non-Noether theorem and non-Noether conserved quantities for the Hamilton systems with the conformable fractional derivatives are obtained. Finally, an example is given to illustrate the results.展开更多
文摘Hemingway established a well-known literary theory - iceberg principle.He said he always attempted to create his literary works according to this principle.In his opinion,if a prose writer has a pretty clear idea of what he writes about,then he can omit the things he knows,and the readers will strongly feel that what the writer has omitted seems to have been written as long as what he writes is authentic.Hemingway himself once said,"The dignity of movement of an iceberg is due to only one eighth of it being above water."Here,one eighth refers to the information given by the author,and the rest refers to the unwrit ten information that can be acquired in readers'imagination on the basis of the one eighth.The Killers is a good example of Hemingway's iceberg principle.This essay will analyse the characters in it to show how the principle was used in this short story.With no doubt the iceberg principle leaves a large space for the readers to imagine and better understand Hemingway's works.
基金Supported by the National Natural Science Foundation of China(10871141)
文摘By using the properties of w-distances and Gerstewitz＇s functions, we first give a vectorial Takahashi＇s nonconvex minimization theorem with a w-distance. From this, we deduce a general vectorial Ekeland＇s variational principle, where the objective function is from a complete metric space into a pre-ordered topological vector space and the perturbation contains a w-distance and a non-decreasing function of the objective function value. From the general vectorial variational principle, we deduce a vectorial Caristfs fixed point theorem with a w-distance. Finally we show that the above three theorems are equivalent to each other. The related known results are generalized and improved. In particular, some conditions in the theorems of [Y. Araya, Ekeland＇s variational principle and its equivalent theorems in vector optimization, J. Math. Anal. Appl. 346（2008）, 9-16] are weakened or even completely relieved.
基金supported by the National Natural Science Foundations of China (Nos. 11972241,11572212,11272227)the Natural Science Foundation of Jiangsu Province(No. BK20191454).
文摘This paper summarized the recent development on Herglotz’s generalized variational principle and its symmetries and conserved quantities for nonconservative dynamical systems.Taking Lagrangian mechanics,Hamiltonian mechanics and Birkhoffian mechanics as three research frames,we introduce Herglotz’s generalized variational principle,dynamical equations of Herglotz type,Noether symmetry and conserved quantities,and their generalization to time-delay dynamics,fractional dynamics and time-scale dynamics,and put forward some problems as suggestions for future research.
基金Supported by the National Natural Science Foundation of China(10972151,11272227)the Innovation Program for Postgraduate in Higher Education Institutions of Jiangsu Province(CXZZ11_0949)the Innovation Program for Postgraduate of Suzhou University of Science and Technology(SKCX11S_050)
文摘The dynamical and physical behavior of a complex system can be more accurately described by using the fractional model.With the successful use of fractional calculus in many areas of science and engineering,it is necessary to extend the classical theories and methods of analytical mechanics to the fractional dynamic system.Birkhoffian mechanics is a natural generalization of Hamiltonian mechanics,and its core is the Pfaff-Birkhoff principle and Birkhoff′s equations.The study on the Birkhoffian mechanics is an important developmental direction of modern analytical mechanics.Here,the fractional Pfaff-Birkhoff variational problem is presented and studied.The definitions of fractional derivatives,the formulae for integration by parts and some other preliminaries are firstly given.Secondly,the fractional Pfaff-Birkhoff principle and the fractional Birkhoff′s equations in terms of RieszRiemann-Liouville fractional derivatives and Riesz-Caputo fractional derivatives are presented respectively.Finally,an example is given to illustrate the application of the results.
基金supported by the National Natural Science Foundation of China (11061023)
文摘In this paper, we introduce a concept of quasi C-lower semicontinuity for setvalued mapping and provide a vector version of Ekeland＇s theorem related to set-valued vector equilibrium problems. As applications, we derive an existence theorem of weakly efficient solution for set-valued vector equilibrium problems without the assumption of convexity of the constraint set and the assumptions of convexity and monotonicity of the set-valued mapping. We also obtain an existence theorem of ε-approximate solution for set-valued vector equilibrium problems without the assumptions of compactness and convexity of the constraint set.
基金supported by National Science Foundation of China (10571044)
文摘This article obtains an explicit expression of the heat kernels on H-type groups and then follow the estimate of heat kernels to deduce the Hardy＇s uncertainty principle on the nilpotent Lie groups.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61070041 and 40775064)
文摘Variational principles are constructed using the semi-inverse method for two kinds of extended Korteweg-de Vries （KdV） equations, which can be regarded as simple models of the nonlinear oceanic internal waves and atmospheric long waves, respectively. The obtained variational principles have also been proved to be correct.
基金supported by the National Natural Science Foundation of China(NSFC)under grant nos.61574059 and 61722402the National Key Research and Development Program of China(2016YFB0700700)+1 种基金Shu-Guang program(15SG20)CC of ECNU
文摘The beneficial effect of the alkali metals such as Na and K on the Cu（In.Ga）Se2 （CIGS） and Cu2ZnSn（S,Se）4 （CZTSSe） solar cells has been extensively investigated in the past two decades, however, in most of the studies the alkali metals were treated as dopants. Several recent studies have showed that the alkali metals may not only act as dopants but also form secondary phases in the absorber layer or on the surfaces of the films. Using the first-principles calculations, we screened out the most probable secondary phases of Na and K in CIGS and CZTSSe, and studied their electronic structures and optical properties. We found that all these alkali chalcogenide compounds have larger band gaps and lower VBM levels than CIGS and CZTSSe, because the existence of strong p-d coupling in CIS and CZTS pushes the valence band maximum （VBM） level up and reduces the band-gaps, while there is no such p-d coupling in these alkali chalcogenides. This band alignment repels the photo-generated holes from the secondary phases and prevents the electron-hole recombination. Moreover, the study on the optical properties of the secondary phases showed that the absorption coefficients of these alkali chalcogenides are much lower than those of CIGS and CZTSSe in the energy range of 0-3.4eV, which means that the alkali chalcogenides may not influence the absorption of solar light. Since the alkali metal dopants can passivate the grain boundaries and increase the hole carrier concentration, and meanwhile their related secondary phases have innocuous effect on the optical absorption and band alignment, we can understand why the alkali metal dopants can improve the CIGS and CZTSSe solar cell performance.
基金supported by the National Natural Science Foundation of China(Grant No.51202250)
文摘The structural,electronic,mechanical properties,and frequency-dependent refractive indexes of GaSe1-xSx（x=0,0.25,and 1） are studied by using the first-principles pseudopotential method within density functional theory.The calculated results demonstrate the relationships between intralayer structure and elastic modulus in GaSe1-xSx（x=0,0.25,and 1）.Doping of ε-GaSe with S strengthens the Ga-X bonds and increases its elastic moduli of C（11） and C（66）.Born effective charge analysis provides an explanation for the modification of cleavage properties about the doping of e-GaSe with S.The calculated results of band gaps suggest that the distance between intralayer atom and substitution of S（Se）,rather than interlayer force,is a key factor influencing the electronic exciton energy of the layer semiconductor.The calculated refractive indexes indicate that the doping of ε-GaSe with S reduces its refractive index and increases its birefringence.
文摘Eugene O’Neill,one of the essential writers of the 20th century,was hailed as the“American Shakespeare.”He enjoyed a high reputation in America owing to his special writing techniques.Long Day’s Journey into Night was his last play,which was an autobiographical play to some extent,and founded on his own authentic experience.The play told the story of an Irish immigrant family’s daily life from day to night.Among the studies at home and abroad,many discuss this play from a psychological perspective and Feminist perspective.The article,instead,gives an interpretation of this play according to Cooperative Principle.Through the analysis of their conversations,it points out what principles their communications violated so as to understand the implied meaning of their conversations.The thesis tries to study the conversations between Mary and other family members,and then demonstrate that Mary is the most tragic person in the family.
文摘This paper discusses a class of vertex-transitive digraphs.It is shown that these digraphs are rational and can be decomposed into Hamiltonian dicycles.
基金supported by the National Natural Science Foundation of China(Grant Nos.10972151 and 11272227)the Innovation Program for Postgraduate in Higher Education Institutions of Jiangsu Province,China(Grant No.CXLX11_0961)
文摘This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and E1-Nabulsi-Hamilton＇s canoni- cal equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of E1-Nabulsi-Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of E1-Nabulsi-Hamilton action under the infinitesimal transformations of the group. Fi- nally, Noether＇s theorems for the non-conservative Hamilton system under the E1-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system.
基金supported by the National Natural Science Foundation of China(Grant Nos.11272287 and 11472247)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT13097)the Key Science and Technology Innovation Team Project of Zhejiang Province,China(Grant No.2013TD18)
文摘In this paper, we present the fractional Hamilton＇s canonical equations and the fractional non-Noether symmetry of Hamilton systems by the conformable fractional derivative. First/y, the exchanging relationship between isochronous variation and fractional derivatives, and the fractional Hamilton principle of the system under this fractional derivative are proposed. Secondly, the fractional Hamilton＇s canonical equations of Hamilton systems based on the Hamilton principle are established. Thirdly, the fractional non-Noether symmetries, non-Noether theorem and non-Noether conserved quantities for the Hamilton systems with the conformable fractional derivatives are obtained. Finally, an example is given to illustrate the results.
