We developed a multinomial-logit-based stochastic user equilibrium(MNL SUE)model incorporating time value of cargo to investigate future proportions of cargo flow through the Northeast Passage(NEP)and the Suez Canal R...We developed a multinomial-logit-based stochastic user equilibrium(MNL SUE)model incorporating time value of cargo to investigate future proportions of cargo flow through the Northeast Passage(NEP)and the Suez Canal Route between representative ports.We studied navigation during the ice-free and ice-covered seasons using sea ice projections for 2070 based on 1991–2021 NEP ice data.Sailing distance and time between selected ports are lower via the NEP than the Suez Canal Route.Under the scenario of year-round operation of the NEP,the proportion of cargo flow through the NEP is estimated to be 68.5%,which represents considerable commercial potential.Proportions are higher for the ice-free season and for ports at high latitudes.We also assessed flow under different scenarios.Under the scenario of fuel price increase,proportion of flow through the NEP in the ice-covered season is expected to increase.If time value is ignored,flow through the NEP is expected to increase all year round.If shippers become more cost-conscious,flow through the NEP is also expected to increase.展开更多
SHIV-CN97001 played an important role in assessing the immune effect and strategy of the AIDS vaccine which included genes of the predominant prevalent HIV-1 strain in China. In this study, SHIV-CN97001 was in vivo pa...SHIV-CN97001 played an important role in assessing the immune effect and strategy of the AIDS vaccine which included genes of the predominant prevalent HIV-1 strain in China. In this study, SHIV-CN97001 was in vivo passaged serially to construct pathogenic SHIV-CN97001/rhesus macaques model. To identify variation in the gp120 region of SHIV-CN97001 during passage, the fragments of gp120 gene were amplified by RT-PCR from the plasma of SHIV-CN97001 infected animals at the peak viral load time point and the gene distances (divergence, diversity) were calculated using DISTANCE. The analysis revealed that the genetic distances of SHIV-CN97001 in the third passage animals were the highest during in vivo passage. It had a relationship between viral divergence from the founder strain and viral replication ability. The nucleic acid sequence of the V3 region was highly conservative. All of the SHIV-CN97001 strains had V3 loop central motif (GPGQ) and were predicted to be using CCR5 co-receptor on the basis of the critical amino acids within V3 loop. These results show that there was no significant increase in the genetic distance during serial passage, and SHIV-CN97001 gp120 gene evolved toward ancestral states upon transmission to a new host. This could partly explain why there was no pathogenic viral strain obtained during in vivo passage.展开更多
In this paper, a numerical method for correlation sensitivity analysis of a nonlinear random vibration system is presented. Based on the first passage failure model, the probability perturbation method is employed to ...In this paper, a numerical method for correlation sensitivity analysis of a nonlinear random vibration system is presented. Based on the first passage failure model, the probability perturbation method is employed to determine the statistical characteristics of failure modes and the correlation between them. The sensitivity of correlation between failure modes with respect to random parameters characterizing the uncertainty of the hysteretic loop is discussed. In a numerical example, a two-DOF shear structure with uncertain hysteretic restoring force is considered. The statistical characteristics of response, failure modes and the sensitivity of random hysteretic loop parameters are provided, and also compared with a Monte Carlo simulation.展开更多
The effects ofincoherency and wave-passage on the nonlinear responses of concrete arch dams are investigated in this study. A double curvature arch dam is selected as a numerical example. The reservoir is modeled as a...The effects ofincoherency and wave-passage on the nonlinear responses of concrete arch dams are investigated in this study. A double curvature arch dam is selected as a numerical example. The reservoir is modeled as a compressible material and the foundation is modeled as a massless medium. Ground motion time-histories are artificially generated using the Monte Carlo simulation approach. Four different finite element models （FEM） are considered： uniform excitation; incoherence effect; wave passage effect; and both incoherence and wave passage effects. It was revealed that modeling multiple-supports excitation could have a significant impact on the structural response of the dam by inducing a pseudo-static effect. Also, it was concluded that the coherency effect overshadows the wave passage effect and the results obtained from non-uniform excitation of FEM, including the wave passage effect, is close to the results of the FEM when it is uniformly excited.展开更多
The eight Taihang passages are important cultural routes in the northern region,and a large number of traditional settlements with northern residential characteristics are distributed along the passages.Traditional se...The eight Taihang passages are important cultural routes in the northern region,and a large number of traditional settlements with northern residential characteristics are distributed along the passages.Traditional settlements along the Feihu passage are studied in the paper,and the temporal and spatial distribution of traditional settlements is sorted out via ArcGIS platform,to explore its historical evolution in time and distribution rule in space.展开更多
基金supported by the Ministry of Education of People’s Republic of China(Grant no.20JHQ016)the National Social Science Fund of China(Grant no.17BGJ059)。
文摘We developed a multinomial-logit-based stochastic user equilibrium(MNL SUE)model incorporating time value of cargo to investigate future proportions of cargo flow through the Northeast Passage(NEP)and the Suez Canal Route between representative ports.We studied navigation during the ice-free and ice-covered seasons using sea ice projections for 2070 based on 1991–2021 NEP ice data.Sailing distance and time between selected ports are lower via the NEP than the Suez Canal Route.Under the scenario of year-round operation of the NEP,the proportion of cargo flow through the NEP is estimated to be 68.5%,which represents considerable commercial potential.Proportions are higher for the ice-free season and for ports at high latitudes.We also assessed flow under different scenarios.Under the scenario of fuel price increase,proportion of flow through the NEP in the ice-covered season is expected to increase.If time value is ignored,flow through the NEP is expected to increase all year round.If shippers become more cost-conscious,flow through the NEP is also expected to increase.
文摘SHIV-CN97001 played an important role in assessing the immune effect and strategy of the AIDS vaccine which included genes of the predominant prevalent HIV-1 strain in China. In this study, SHIV-CN97001 was in vivo passaged serially to construct pathogenic SHIV-CN97001/rhesus macaques model. To identify variation in the gp120 region of SHIV-CN97001 during passage, the fragments of gp120 gene were amplified by RT-PCR from the plasma of SHIV-CN97001 infected animals at the peak viral load time point and the gene distances (divergence, diversity) were calculated using DISTANCE. The analysis revealed that the genetic distances of SHIV-CN97001 in the third passage animals were the highest during in vivo passage. It had a relationship between viral divergence from the founder strain and viral replication ability. The nucleic acid sequence of the V3 region was highly conservative. All of the SHIV-CN97001 strains had V3 loop central motif (GPGQ) and were predicted to be using CCR5 co-receptor on the basis of the critical amino acids within V3 loop. These results show that there was no significant increase in the genetic distance during serial passage, and SHIV-CN97001 gp120 gene evolved toward ancestral states upon transmission to a new host. This could partly explain why there was no pathogenic viral strain obtained during in vivo passage.
基金National Natural Science Foundation of ChinaUnder Grant No: 50535010
文摘In this paper, a numerical method for correlation sensitivity analysis of a nonlinear random vibration system is presented. Based on the first passage failure model, the probability perturbation method is employed to determine the statistical characteristics of failure modes and the correlation between them. The sensitivity of correlation between failure modes with respect to random parameters characterizing the uncertainty of the hysteretic loop is discussed. In a numerical example, a two-DOF shear structure with uncertain hysteretic restoring force is considered. The statistical characteristics of response, failure modes and the sensitivity of random hysteretic loop parameters are provided, and also compared with a Monte Carlo simulation.
文摘The effects ofincoherency and wave-passage on the nonlinear responses of concrete arch dams are investigated in this study. A double curvature arch dam is selected as a numerical example. The reservoir is modeled as a compressible material and the foundation is modeled as a massless medium. Ground motion time-histories are artificially generated using the Monte Carlo simulation approach. Four different finite element models （FEM） are considered： uniform excitation; incoherence effect; wave passage effect; and both incoherence and wave passage effects. It was revealed that modeling multiple-supports excitation could have a significant impact on the structural response of the dam by inducing a pseudo-static effect. Also, it was concluded that the coherency effect overshadows the wave passage effect and the results obtained from non-uniform excitation of FEM, including the wave passage effect, is close to the results of the FEM when it is uniformly excited.
基金Sponsored by National Natural Science Foundation of China (51608007)。
文摘The eight Taihang passages are important cultural routes in the northern region,and a large number of traditional settlements with northern residential characteristics are distributed along the passages.Traditional settlements along the Feihu passage are studied in the paper,and the temporal and spatial distribution of traditional settlements is sorted out via ArcGIS platform,to explore its historical evolution in time and distribution rule in space.
