We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfex...We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfexchanges with the rate kernels Kl（k,j） = K1kj and K2（h,j） = K2kj, respectively. The actions of the population and asset aggregations on the aggregation evolution of resource aggregates are described by the population-catalyzed monomer death of resource aggregates and asset-catalyzed monomer birth of resource aggregates with the rate kerne/s J1（k,j）=J1k and J2（k,j） = J2k, respectively. Meanwhile, the asset and resource aggregates conjunctly catalyze the monomer birth of population aggregates with the rate kernel I1 （k,i,j） = I1ki^μjη, and population and resource aggregates conjunctly catalyze the monomer birth of asset aggregates with the rate kernel /2（k, i, j） = I2ki^νj^η. The kinetic behaviors of species A, B, and C are investigated by means of the mean-field rate equation approach. The effects of the population-catalyzed death and asset-catalyzed birth on the evolution of resource aggregates based on the self-exchanges of population and asset appear in effective forms. The coefficients of the effective population-catalyzed death and the asset-catalyzed birth are expressed as J1e = J1/K1 and J2e= J2/K2, respectively. The aggregate size distribution of C species is found to be crucially dominated by the competition between the effective death and the effective birth. It satisfies the conventional scaling form, generalized scaling form, and modified scaling form in the cases of J1e〈J2e, J1e=J2e, and J1e〉J2e, respectively. Meanwhile, we also find the aggregate size distributions of populations and assets both fall into two distinct categories for different parameters μ,ν, and η： （i） When μ=ν=η=0 and μ=ν=η=1, the population and asset aggregates obey the generalized scaling forms; and （ii） When μ=ν=1,η=0, and μ=ν=η=1, the population and asset aggregates experience gelation transitions at finite times and the scaling forms break down.展开更多
Concrete footbridges, due to their mass, stiffness and damping, are perceived as strucaires more resistant to vibration caused by dynamic action of the users. In order to verify the dynamic behaviour of concrete footb...Concrete footbridges, due to their mass, stiffness and damping, are perceived as strucaires more resistant to vibration caused by dynamic action of the users. In order to verify the dynamic behaviour of concrete footbridges, a series of field tests and numerical analyses have been carried out. In the paper, the results of the dynamic field tests of three medium span concrete footbridges with different structural systems （frame, beam and arch footbridges） and their dynamic characteristics （mass, stiffness and damping） are presented. The field tests were carried out for different types of vibration excitation caused by walking, running and jumping persons. Furthermore, the vibrational comfort criteria for footbridges are shortly described and verified for examined structures. The study were supplemented by numerical calculation of natural mode shapes and frequencies of the structures using the 3D FEA （finite element analysis） models with elastic supports elements in order to ensure the compatibility of the calculated and measured mode shapes of the footbridges.展开更多
The rational design of urban public space has more and more attention of the community; in the end, people need public spaces of an active exploration and attempt. Through human experience of urban public space, the d...The rational design of urban public space has more and more attention of the community; in the end, people need public spaces of an active exploration and attempt. Through human experience of urban public space, the design of public space in the city questioned the rationality, emphasized the human behavior activities on public space design requirements, and emphasized the place of people, human behavior activities, and the activities of the Trinity design ideas. By comparing the two public spaces Analysis of Chongqing, it further emphasized the left of human activity, human stories and spirit; public space has lost its significance.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10775104, 10275048, and 10305009the Zhejiang Provincial Natural Science Foundation of China under Grant No. 102067
文摘We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfexchanges with the rate kernels Kl（k,j） = K1kj and K2（h,j） = K2kj, respectively. The actions of the population and asset aggregations on the aggregation evolution of resource aggregates are described by the population-catalyzed monomer death of resource aggregates and asset-catalyzed monomer birth of resource aggregates with the rate kerne/s J1（k,j）=J1k and J2（k,j） = J2k, respectively. Meanwhile, the asset and resource aggregates conjunctly catalyze the monomer birth of population aggregates with the rate kernel I1 （k,i,j） = I1ki^μjη, and population and resource aggregates conjunctly catalyze the monomer birth of asset aggregates with the rate kernel /2（k, i, j） = I2ki^νj^η. The kinetic behaviors of species A, B, and C are investigated by means of the mean-field rate equation approach. The effects of the population-catalyzed death and asset-catalyzed birth on the evolution of resource aggregates based on the self-exchanges of population and asset appear in effective forms. The coefficients of the effective population-catalyzed death and the asset-catalyzed birth are expressed as J1e = J1/K1 and J2e= J2/K2, respectively. The aggregate size distribution of C species is found to be crucially dominated by the competition between the effective death and the effective birth. It satisfies the conventional scaling form, generalized scaling form, and modified scaling form in the cases of J1e〈J2e, J1e=J2e, and J1e〉J2e, respectively. Meanwhile, we also find the aggregate size distributions of populations and assets both fall into two distinct categories for different parameters μ,ν, and η： （i） When μ=ν=η=0 and μ=ν=η=1, the population and asset aggregates obey the generalized scaling forms; and （ii） When μ=ν=1,η=0, and μ=ν=η=1, the population and asset aggregates experience gelation transitions at finite times and the scaling forms break down.
文摘Concrete footbridges, due to their mass, stiffness and damping, are perceived as strucaires more resistant to vibration caused by dynamic action of the users. In order to verify the dynamic behaviour of concrete footbridges, a series of field tests and numerical analyses have been carried out. In the paper, the results of the dynamic field tests of three medium span concrete footbridges with different structural systems （frame, beam and arch footbridges） and their dynamic characteristics （mass, stiffness and damping） are presented. The field tests were carried out for different types of vibration excitation caused by walking, running and jumping persons. Furthermore, the vibrational comfort criteria for footbridges are shortly described and verified for examined structures. The study were supplemented by numerical calculation of natural mode shapes and frequencies of the structures using the 3D FEA （finite element analysis） models with elastic supports elements in order to ensure the compatibility of the calculated and measured mode shapes of the footbridges.
文摘The rational design of urban public space has more and more attention of the community; in the end, people need public spaces of an active exploration and attempt. Through human experience of urban public space, the design of public space in the city questioned the rationality, emphasized the human behavior activities on public space design requirements, and emphasized the place of people, human behavior activities, and the activities of the Trinity design ideas. By comparing the two public spaces Analysis of Chongqing, it further emphasized the left of human activity, human stories and spirit; public space has lost its significance.
