An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designe...An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.展开更多
In this article, we study the structures of the pseudoscalar mesons π, K and the scalar diquarks U^a, D^a, Sa in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with t...In this article, we study the structures of the pseudoscalar mesons π, K and the scalar diquarks U^a, D^a, Sa in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with the confining effective potential. The u, d, s quarks have small current masses, and the renormalization is very large, the mass poles in the timelike region are absent which implements confinement naturally. The Bethe-Salpeter wavefunctions of the pseudoscalar mesons π, K, and the scalar diquarks U^a, D^a, S^a have the same type （Gaussian type） momentum dependence, center around zero momentum and extend to the energy scale about q^2 = 1 GeV^2, which happens to be the energy scale for the chiral symmetry breaking, the strong interactions in the infrargd region result in bound （or quasl-bound） states. The numerical results for the masses and decay constants of the π and K mesons can reproduce the experimental values, and the ground state masses of the scalar diquarks U^a, D^a, S^a are consistent with the existing theoretical calculations. We suggest a new Lagrangian which may explain the uncertainty of the masses of the scalar diauarks.展开更多
Lead-free double perovskite nanocrystals(NCs),such as Cs2AgInCl6,have attracted considerable attention as stable and non-toxic alternatives to lead-based perovskites.However,the low photoluminescence(PL)intensity of p...Lead-free double perovskite nanocrystals(NCs),such as Cs2AgInCl6,have attracted considerable attention as stable and non-toxic alternatives to lead-based perovskites.However,the low photoluminescence(PL)intensity of pristine Cs_(2)AgInCl_(6)limits its practical applications.In this study,a series of Cs_(2)AgIn_(1−γ−x)Bi_(x)La_(γ)Cl_(6)NCs were synthesized to break the parity-forbidden transition and modify the associated optical functionalities.A broadband bright warm-white emission in the visible region was achieved,with an excellent PL quantum yield of 60%.The dynamic mechanism,involving ultrafast transient absorption,suggests that high-efficiency PL is induced by triplet self-trapping exciton emission.The incorporation of La^(3+)-Bi^(3)+facilitated the singlet–triplet transition by increasing the lifetime and quickening the intersystem crossing process.This finding provides a reliable method for optimizing the optical properties of emerging lead-free halide perovskite NCs.展开更多
文摘An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.
基金The project supported by National Natural Science Foundation of China under Grant No. 10405009 The authors are indebted to Dr： J. He （IHEP）, Dr. X.B. nuang （PKU） and Dr. L. Li （GSCAS） for numerous help. Without them, the work would not be finished. The authors would also like to thank Prof. C.D. Roberts for providing us some important literatures.
文摘In this article, we study the structures of the pseudoscalar mesons π, K and the scalar diquarks U^a, D^a, Sa in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with the confining effective potential. The u, d, s quarks have small current masses, and the renormalization is very large, the mass poles in the timelike region are absent which implements confinement naturally. The Bethe-Salpeter wavefunctions of the pseudoscalar mesons π, K, and the scalar diquarks U^a, D^a, S^a have the same type （Gaussian type） momentum dependence, center around zero momentum and extend to the energy scale about q^2 = 1 GeV^2, which happens to be the energy scale for the chiral symmetry breaking, the strong interactions in the infrargd region result in bound （or quasl-bound） states. The numerical results for the masses and decay constants of the π and K mesons can reproduce the experimental values, and the ground state masses of the scalar diquarks U^a, D^a, S^a are consistent with the existing theoretical calculations. We suggest a new Lagrangian which may explain the uncertainty of the masses of the scalar diauarks.
基金the National Key Research and Development Program of China(2017YFA0204800)the National Natural Science Foundation of China(21833009,21533010,and 21525315)+2 种基金the Scientific Instrument Developing Project of the Chinese Academy of Sciences(YJKYYQ20190003)Liaoning Revitalization Talents Program(XLYC1802126)Dalian City Foundation for Science and Technology Innovation(2019J12GX031).
文摘Lead-free double perovskite nanocrystals(NCs),such as Cs2AgInCl6,have attracted considerable attention as stable and non-toxic alternatives to lead-based perovskites.However,the low photoluminescence(PL)intensity of pristine Cs_(2)AgInCl_(6)limits its practical applications.In this study,a series of Cs_(2)AgIn_(1−γ−x)Bi_(x)La_(γ)Cl_(6)NCs were synthesized to break the parity-forbidden transition and modify the associated optical functionalities.A broadband bright warm-white emission in the visible region was achieved,with an excellent PL quantum yield of 60%.The dynamic mechanism,involving ultrafast transient absorption,suggests that high-efficiency PL is induced by triplet self-trapping exciton emission.The incorporation of La^(3+)-Bi^(3)+facilitated the singlet–triplet transition by increasing the lifetime and quickening the intersystem crossing process.This finding provides a reliable method for optimizing the optical properties of emerging lead-free halide perovskite NCs.
