The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation meth...The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation method and the Extended Negative Factor Counter method at ab initio level. The result indicated that: (1) Amino acid residues, the molecular orbitals of which composed the main components of frontier orbitals of protein chain L (M), are located at the random coil areas of chain L (alpha helix areas of chain M). Since the random coil is flexible and more easy to change its conformation in the electron transfer process and to reduce the energy of the system, and the structure of the alpha helix is reletively stable, this difference might be one of the causes for the electron transfer in photosynthetic reaction center (PRC) only takes place along the L branch. (2) The His residues which axially coordinated to the 'special pair' P and accessory chlorophyll molecules (ABChls) are essentially important for the E-LUMO levels of P and ABChl. But, the corresponding molecular orbitals of these His residues do not appear in the composition of frontier orbitals of protein chains. It means that the interaction between pigment molecules and protein chains do not influence the contribution to the frontier orbitals of protein chains explicitly, but influences the corresponding E-LUMO levels significantly.展开更多
Most source number estimation methods based on the eigenvalues are decomposed by covariance matrix in MUSIC algorithm. To develop the source number estimation method which has lower signal to noise ratio and is suitab...Most source number estimation methods based on the eigenvalues are decomposed by covariance matrix in MUSIC algorithm. To develop the source number estimation method which has lower signal to noise ratio and is suitable to both correlated and uncorrelated impinging signals, a new source number estimation method called beam eigenvalue method (BEM) is proposed in this paper. Through analyzing the space power spectrum and the correlation of the line array, the covariance matrix is constructed in a new way, which is decided by the line array shape when the signal frequency is given. Both of the theory analysis and the simulation results show that the BEM method can estimate the source number for correlated signals and can be more effective at lower signal to noise ratios than the normal source number estimation methods.展开更多
Using the coordinate transformation method, we study the polynomial solutions of the Schr6dinger equation with position-dependent mass （PDM）. The explicit expressions for the potentials, energy eigenvalues, and eige...Using the coordinate transformation method, we study the polynomial solutions of the Schr6dinger equation with position-dependent mass （PDM）. The explicit expressions for the potentials, energy eigenvalues, and eigenfunctions of the systems are given. The issues related to normalization of the wavefunetions and Hermiticity of the Hamiltonian are also analyzed.展开更多
Based on an iterative method for solving the groundstate of Schrodinger equation, it is found that a kind of generalized Sombrero-shaped potentials in N-dimensional space has groundstates with zero eigenvalue. The res...Based on an iterative method for solving the groundstate of Schrodinger equation, it is found that a kind of generalized Sombrero-shaped potentials in N-dimensional space has groundstates with zero eigenvalue. The restrictions on the parameters in the potential are discussed.展开更多
The complete band representations(BRs)have been constructed in the work of topological quantum chemistry.Each BR is expressed by either a localized orbital at a Wyckoff site in real space,or by a set of irreducible re...The complete band representations(BRs)have been constructed in the work of topological quantum chemistry.Each BR is expressed by either a localized orbital at a Wyckoff site in real space,or by a set of irreducible representations in momentum space.In this work,we define unconventional materials with a common feature of the mismatch between average electronic centers and atomic positions.They can be effectively diagnosed as whose occupied bands can be expressed as a sum of elementary BRs(eBRs),but not a sum of atomic-orbital-induced BRs(aBRs).The existence of an essential BR at an empty site is described by nonzero real-space invariants(RSIs).The"valence"states can be derived by the aBR decomposition,and unconventional materials are supposed to have an uncompensated total"valence"state.The high-throughput screening for unconventional materials has been performed through the first-principles calculations.We have discovered 423 unconventional compounds,including thermoelectronic materials,higher-order topological insulators,electrides,hydrogen storage materials,hydrogen evolution reaction electrocatalysts,electrodes,and superconductors.The diversity of these interesting properties and applications would be widely studied in the future.展开更多
文摘The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation method and the Extended Negative Factor Counter method at ab initio level. The result indicated that: (1) Amino acid residues, the molecular orbitals of which composed the main components of frontier orbitals of protein chain L (M), are located at the random coil areas of chain L (alpha helix areas of chain M). Since the random coil is flexible and more easy to change its conformation in the electron transfer process and to reduce the energy of the system, and the structure of the alpha helix is reletively stable, this difference might be one of the causes for the electron transfer in photosynthetic reaction center (PRC) only takes place along the L branch. (2) The His residues which axially coordinated to the 'special pair' P and accessory chlorophyll molecules (ABChls) are essentially important for the E-LUMO levels of P and ABChl. But, the corresponding molecular orbitals of these His residues do not appear in the composition of frontier orbitals of protein chains. It means that the interaction between pigment molecules and protein chains do not influence the contribution to the frontier orbitals of protein chains explicitly, but influences the corresponding E-LUMO levels significantly.
文摘Most source number estimation methods based on the eigenvalues are decomposed by covariance matrix in MUSIC algorithm. To develop the source number estimation method which has lower signal to noise ratio and is suitable to both correlated and uncorrelated impinging signals, a new source number estimation method called beam eigenvalue method (BEM) is proposed in this paper. Through analyzing the space power spectrum and the correlation of the line array, the covariance matrix is constructed in a new way, which is decided by the line array shape when the signal frequency is given. Both of the theory analysis and the simulation results show that the BEM method can estimate the source number for correlated signals and can be more effective at lower signal to noise ratios than the normal source number estimation methods.
文摘Using the coordinate transformation method, we study the polynomial solutions of the Schr6dinger equation with position-dependent mass （PDM）. The explicit expressions for the potentials, energy eigenvalues, and eigenfunctions of the systems are given. The issues related to normalization of the wavefunetions and Hermiticity of the Hamiltonian are also analyzed.
文摘Based on an iterative method for solving the groundstate of Schrodinger equation, it is found that a kind of generalized Sombrero-shaped potentials in N-dimensional space has groundstates with zero eigenvalue. The restrictions on the parameters in the potential are discussed.
基金supported by the National Natural Science Foundation of China(11974395 and 12188101)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB33000000)+6 种基金the Center for Materials Genomesupport from the Ministry of Science and Technology of China under Grant Nos.2016YFA0300600 and 2018YFA0305700the Chinese Academy of Sciences under Grant No.XDB28000000the Science Challenge Project(TZ2016004)the K.C.Wong Education Foundation(GJTD-2018-01)Beijing Municipal Science&Technology Commission(Z181100004218001)Beijing Natural Science Foundation(Z180008)。
文摘The complete band representations(BRs)have been constructed in the work of topological quantum chemistry.Each BR is expressed by either a localized orbital at a Wyckoff site in real space,or by a set of irreducible representations in momentum space.In this work,we define unconventional materials with a common feature of the mismatch between average electronic centers and atomic positions.They can be effectively diagnosed as whose occupied bands can be expressed as a sum of elementary BRs(eBRs),but not a sum of atomic-orbital-induced BRs(aBRs).The existence of an essential BR at an empty site is described by nonzero real-space invariants(RSIs).The"valence"states can be derived by the aBR decomposition,and unconventional materials are supposed to have an uncompensated total"valence"state.The high-throughput screening for unconventional materials has been performed through the first-principles calculations.We have discovered 423 unconventional compounds,including thermoelectronic materials,higher-order topological insulators,electrides,hydrogen storage materials,hydrogen evolution reaction electrocatalysts,electrodes,and superconductors.The diversity of these interesting properties and applications would be widely studied in the future.
