Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This...Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This collaborative optimization problem is formulated as the integer programming,which aims at minimizing the total truck travel distance.And decision variables are the berthing positions for visiting ships and the storage positions for export containers.Meanwhile,this paper demonstrates the complexity of the problem in theory.And the hybrid tabu genetic algorithm is designed to solve the problem to obtain the optimal berth allocation position and export container storage position.For this algorithm,the rule is applied to generate the initial feasible solutions,and the crossover and mutation operation are simultaneously applied to optimize the initial solutions.Finally,this paper discusses two different scenes:the same berth scene and the same ship scene.The influence of two different scenes on truck travel distance is analyzed by different numerical examples.Numerical examples’results show that the collaborative optimization of berth allocation and yard storage can effectively shorten the truck travel distance and improve the efficiency of terminal operation,which provides the decision support for terminal operators.展开更多
Steric tuning of the aryl ortho-positions and backbone of an α-diimine pro-ligand significantly impacts Ni(Ⅱ)and Pd(Ⅱ)-catalyzed olefin(co)polymerization.Herein,dual steric enhancement in the ortho-positions and ba...Steric tuning of the aryl ortho-positions and backbone of an α-diimine pro-ligand significantly impacts Ni(Ⅱ)and Pd(Ⅱ)-catalyzed olefin(co)polymerization.Herein,dual steric enhancement in the ortho-positions and backbone was achieved through the combination of a bulky vicinal t-butylated dearomatized acenaphthyl backbone and bulky ortho substituents(i-Pr or CHAr_(2)).Single-crystal X-ray analysis showed that this combination shielded the back and axial spaces of the metal center.In the ortho-diisopropyl(i-Pr)substituted system,compared to Ni1 and Pd1 with the acenaphthyl backbone,Ni2 and Pd2 with the bulky dearomatized acenaphthyl backbone showed improved catalytic activity and generated a polymer with a higher molecular weight and slightly changed branching density.In the ortho-diarylmethyl(CHAr_(2))substituted system,the opposite trend that the bulky dearomatized acenaphthyl backbone led to lower catalytic activity and polymer molecular weight was observed,which may be attributed to the slow propagation rate caused by the excessively high and rigid steric effects in these catalysts.In contrast to ortho-diarylmethyl substituted Ni(Ⅱ)catalysts,the branching density of the polymer generated by the Pd(Ⅱ)analogues decreased when the more bulky dearomatized acenaphthyl backbone was employed.The non-dependence of the branching density on polymerization temperature in catalysts with a dearomatized acenaphthyl backbone(Ni4 and Pd4)was also observed in comparison with catalysts with the acenaphthyl backbone(Ni3 and Pd3),suggesting the disruption of the π-π interaction between the diarylmethyl moiety and the acenaphthene aromatic plane in Ni4 and Pd4.Particularly,the dearomatized acenaphthyl backbone promoted the incorporation of polar monomers(methyl acrylate(MA)and ethylene-acrylic acid(AA))in ethylene-polar monomer copolymerization.展开更多
Metal-organic frameworks(MOFs)have shown excellent adsorption and degradation performance towards different kinds of dyes but suffer problems in the desorption process,where adsorbates cannot be completely removed and...Metal-organic frameworks(MOFs)have shown excellent adsorption and degradation performance towards different kinds of dyes but suffer problems in the desorption process,where adsorbates cannot be completely removed and may cause energy waste or secondary pollution by the repeated washing with eluent,as well as their relatively weak stability in aqueous solutions.Thus,it is very attractive to integrate MOFs with active ingredients to prepare MOF-based composites with dye adsorption and degradation ability.The reported fabrication method of MOF@TiO_(2) usually involves high crystallization temperature or contains acid or base additives,which are unfriendly to MOF structures.Here,we report the design of MOF@TiO_(2) core-shell nanostructures via a surfactant-free amorphous TiO_(2) coating followed by water-assisted crystallization at a low temperature(100℃)below the decomposition temperature of most MOFs.Owing to the mild crystallization conditions,MOF cores are maintained and TiO_(2) shells crystallize to an active anatase phase.The obtained MOF@TiO_(2) core-shell nanostructures showed excellent dye removal efficiency and stability for anionic dyes,which can remove 98% dye after five adsorption and photodegradation cycles due to the synergistic effect of MOF cores and TiO_(2) shells.The design concept and synthetic strategy via the water-assisted crystallization method for labile MOF materials encapsulated in functional TiO_(2) shells may be used to construct other multifunctional MOF core-shell nanostructures,broadening their applications in diverse fields.展开更多
This paper considers the ship routing optimization problem in a hub-and-spoke network. A routing optimization model for multi-type containerships with time deadlines is established, and the target is to minimize the t...This paper considers the ship routing optimization problem in a hub-and-spoke network. A routing optimization model for multi-type containerships with time deadlines is established, and the target is to minimize the total cost, which consists of the total travelling cost, total service cost and total waiting cost. The model is set up through an improved genetic algorithm. The study data are from the Pearl River Delta region of China, which include i hub port and 29 feeder ports and have a population of 30 million. Result shows that when the iteration time reaches 190, the total cost comes to 521 thousand yuan near the optimal value. There are 6 routes, including 3 containerships of 100 TEU, 2 containerships of 150 TEU and 1 containership of 200 TEU. At the same time, in the single-type containerships case, there are 7 routes, and when the iteration time reaches 120, the total cost comes to 573 thousand yuan, which is close to the optimal value. Comparing the two cases, it shows that the model for multi-type containerships with time deadlines is reasonable, and the algorithm is practicable. In the last, three factors, which may affect the total cost to carry out sensitivity analysis are chosen. It shows that time deadline, eontainership capacity and cargo handling capacity of each port have significant influence on the total cost. It is also shown that the total cost for multi-type containerships is always less than that for the single-type containerships.展开更多
文摘Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This collaborative optimization problem is formulated as the integer programming,which aims at minimizing the total truck travel distance.And decision variables are the berthing positions for visiting ships and the storage positions for export containers.Meanwhile,this paper demonstrates the complexity of the problem in theory.And the hybrid tabu genetic algorithm is designed to solve the problem to obtain the optimal berth allocation position and export container storage position.For this algorithm,the rule is applied to generate the initial feasible solutions,and the crossover and mutation operation are simultaneously applied to optimize the initial solutions.Finally,this paper discusses two different scenes:the same berth scene and the same ship scene.The influence of two different scenes on truck travel distance is analyzed by different numerical examples.Numerical examples’results show that the collaborative optimization of berth allocation and yard storage can effectively shorten the truck travel distance and improve the efficiency of terminal operation,which provides the decision support for terminal operators.
基金Natural Science Foundation of Shandong Province(ZR2022MB038)the Young Talents Invitation Program of Shandong Provincial CollegesUniversities and the Young Mentor Visiting Program for support.
文摘Steric tuning of the aryl ortho-positions and backbone of an α-diimine pro-ligand significantly impacts Ni(Ⅱ)and Pd(Ⅱ)-catalyzed olefin(co)polymerization.Herein,dual steric enhancement in the ortho-positions and backbone was achieved through the combination of a bulky vicinal t-butylated dearomatized acenaphthyl backbone and bulky ortho substituents(i-Pr or CHAr_(2)).Single-crystal X-ray analysis showed that this combination shielded the back and axial spaces of the metal center.In the ortho-diisopropyl(i-Pr)substituted system,compared to Ni1 and Pd1 with the acenaphthyl backbone,Ni2 and Pd2 with the bulky dearomatized acenaphthyl backbone showed improved catalytic activity and generated a polymer with a higher molecular weight and slightly changed branching density.In the ortho-diarylmethyl(CHAr_(2))substituted system,the opposite trend that the bulky dearomatized acenaphthyl backbone led to lower catalytic activity and polymer molecular weight was observed,which may be attributed to the slow propagation rate caused by the excessively high and rigid steric effects in these catalysts.In contrast to ortho-diarylmethyl substituted Ni(Ⅱ)catalysts,the branching density of the polymer generated by the Pd(Ⅱ)analogues decreased when the more bulky dearomatized acenaphthyl backbone was employed.The non-dependence of the branching density on polymerization temperature in catalysts with a dearomatized acenaphthyl backbone(Ni4 and Pd4)was also observed in comparison with catalysts with the acenaphthyl backbone(Ni3 and Pd3),suggesting the disruption of the π-π interaction between the diarylmethyl moiety and the acenaphthene aromatic plane in Ni4 and Pd4.Particularly,the dearomatized acenaphthyl backbone promoted the incorporation of polar monomers(methyl acrylate(MA)and ethylene-acrylic acid(AA))in ethylene-polar monomer copolymerization.
基金the National Natural Science Foundation of China(grants 21920102005,21871104,and 22172058)the 111 Project of China(B17020)for supporting this work.
文摘Metal-organic frameworks(MOFs)have shown excellent adsorption and degradation performance towards different kinds of dyes but suffer problems in the desorption process,where adsorbates cannot be completely removed and may cause energy waste or secondary pollution by the repeated washing with eluent,as well as their relatively weak stability in aqueous solutions.Thus,it is very attractive to integrate MOFs with active ingredients to prepare MOF-based composites with dye adsorption and degradation ability.The reported fabrication method of MOF@TiO_(2) usually involves high crystallization temperature or contains acid or base additives,which are unfriendly to MOF structures.Here,we report the design of MOF@TiO_(2) core-shell nanostructures via a surfactant-free amorphous TiO_(2) coating followed by water-assisted crystallization at a low temperature(100℃)below the decomposition temperature of most MOFs.Owing to the mild crystallization conditions,MOF cores are maintained and TiO_(2) shells crystallize to an active anatase phase.The obtained MOF@TiO_(2) core-shell nanostructures showed excellent dye removal efficiency and stability for anionic dyes,which can remove 98% dye after five adsorption and photodegradation cycles due to the synergistic effect of MOF cores and TiO_(2) shells.The design concept and synthetic strategy via the water-assisted crystallization method for labile MOF materials encapsulated in functional TiO_(2) shells may be used to construct other multifunctional MOF core-shell nanostructures,broadening their applications in diverse fields.
基金supported by the National Nature Science Foundation of China(71072081)the Key Project of National Social Science Fund(14ZDB131)
文摘This paper considers the ship routing optimization problem in a hub-and-spoke network. A routing optimization model for multi-type containerships with time deadlines is established, and the target is to minimize the total cost, which consists of the total travelling cost, total service cost and total waiting cost. The model is set up through an improved genetic algorithm. The study data are from the Pearl River Delta region of China, which include i hub port and 29 feeder ports and have a population of 30 million. Result shows that when the iteration time reaches 190, the total cost comes to 521 thousand yuan near the optimal value. There are 6 routes, including 3 containerships of 100 TEU, 2 containerships of 150 TEU and 1 containership of 200 TEU. At the same time, in the single-type containerships case, there are 7 routes, and when the iteration time reaches 120, the total cost comes to 573 thousand yuan, which is close to the optimal value. Comparing the two cases, it shows that the model for multi-type containerships with time deadlines is reasonable, and the algorithm is practicable. In the last, three factors, which may affect the total cost to carry out sensitivity analysis are chosen. It shows that time deadline, eontainership capacity and cargo handling capacity of each port have significant influence on the total cost. It is also shown that the total cost for multi-type containerships is always less than that for the single-type containerships.
