The general relativistic frame dragging effect on the properties,such as the moments of inertia and the radiiof gyration of fast rotating neutron stars with a uniform strong magnetic field,is calculated accurate to th...The general relativistic frame dragging effect on the properties,such as the moments of inertia and the radiiof gyration of fast rotating neutron stars with a uniform strong magnetic field,is calculated accurate to the first orderin the uniform angular velocity.The results show that compared with the corresponding non-rotating static sphericalsymmetric neutron star with a weaker magnetic field,a fast rotating neutron star(millisecond pulsar)with a strongermagnetic field has a relative smaller moment of inertia and radius of gyration.展开更多
To evaluate the importance of the canyon topography effects on large structures, based on a rigid frame bridge across a 137-m-deep and 600-m-wide canyon, the seismic response of the canyon site is analyzed using a two...To evaluate the importance of the canyon topography effects on large structures, based on a rigid frame bridge across a 137-m-deep and 600-m-wide canyon, the seismic response of the canyon site is analyzed using a two-dimensional finite element model under different seismic SV waves with the assumptions of vertical incidence and oblique incidence to obtain the ground motions, which are used as the excitation input on the pier foundations of the bridge with improved large mass method. The results indicate that canyon topography has significant influences on the ground motions in terms of inci- dent angle. The peak ground acceleration values vary greatly from the bottom of the canyon to the upper comers. Under ver- tical incident SV waves, at the upper comers of canyon the peak ground accelerations greatly increase; whereas the peak ground accelerations diminish at the bottom comers of canyon. Under oblique incident SV waves, the shaking of the canyon slope perpendicular to the incidence direction is much more severe than that of the opposite side of canyon. And the ground surface has been characterized by larger deformations in the case of oblique incident waves. It is also concluded that the low piers and frame of the continuous rigid frame bridge ape more sensitive to the multi-support seismic excitations than the flexible high piers. The canyon topography as well as the oblique incidence of the waves brings the continuous rigid frame bridge severe responses, which should be taken into account in bridge design.展开更多
Seismic ground motions of two neighboring mountains and the free surface between them are calculated under the SV seismic waves with three different incident angles. The results are then taken as the inputs of multi-p...Seismic ground motions of two neighboring mountains and the free surface between them are calculated under the SV seismic waves with three different incident angles. The results are then taken as the inputs of multi-point seismic excitations for the foundation of a long-span bridge built over the valley in the analysis considering the integrated influence of traveling wave and topography. On the basis of a dynamic analytical method, a finite element model is created for the seismic responses of a four-span rigid-frame bridge of 440 m. The pier-top displacement and the pier-bottom internal force of the bridge are calculated. Then the results are compared with those considering traveling-wave effect only. The conclusions can serve as a seismic design reference for the structures located on the complex mountain topography.展开更多
在煤矿技术致因事故率逐年下降、人因事故率却高居不下的背景下,煤矿安全标识作为安全信息的重要载体,如何影响矿工的安全认知和决策过程成为信息时代重要的研究内容。为探索安全标识有效性影响机理,降低煤矿安全事故发生概率,结合框架...在煤矿技术致因事故率逐年下降、人因事故率却高居不下的背景下,煤矿安全标识作为安全信息的重要载体,如何影响矿工的安全认知和决策过程成为信息时代重要的研究内容。为探索安全标识有效性影响机理,降低煤矿安全事故发生概率,结合框架效应,借助ErgoLAB Experiment平台和Tobii Pro Nano眼动仪收集了30名被试的试验数据,研究在不同作业情境(高风险或低风险)下,不同损益框架的煤矿安全标识对矿工再认记忆任务和眼动行为的影响。结果表明:高风险作业情境及使用损失框架展示的安全标识能显著提高被试的再认记忆正确率;在低风险作业情境的安全标识设计中,可以突出潜在风险和损失,以吸引矿工有限的安全注意力。研究结果可为安全标识优化设计提供证据和参考,有助于提高煤矿的安全生产水平。展开更多
基金National Natural Science Foundation of China under Grant Nos.10647116 and 10575140the China Postdoctoral Science Foundation under Grant No.2005037175
文摘The general relativistic frame dragging effect on the properties,such as the moments of inertia and the radiiof gyration of fast rotating neutron stars with a uniform strong magnetic field,is calculated accurate to the first orderin the uniform angular velocity.The results show that compared with the corresponding non-rotating static sphericalsymmetric neutron star with a weaker magnetic field,a fast rotating neutron star(millisecond pulsar)with a strongermagnetic field has a relative smaller moment of inertia and radius of gyration.
基金supported by National Natural Science Foundation of China (No. 50708100)National Science and Technology Support Project of China (No. 2006BAC13B02)partially by Basic Research Program of Institute of Mechanics Engineering, China Earthquake Administration (No. 2007B02)
文摘To evaluate the importance of the canyon topography effects on large structures, based on a rigid frame bridge across a 137-m-deep and 600-m-wide canyon, the seismic response of the canyon site is analyzed using a two-dimensional finite element model under different seismic SV waves with the assumptions of vertical incidence and oblique incidence to obtain the ground motions, which are used as the excitation input on the pier foundations of the bridge with improved large mass method. The results indicate that canyon topography has significant influences on the ground motions in terms of inci- dent angle. The peak ground acceleration values vary greatly from the bottom of the canyon to the upper comers. Under ver- tical incident SV waves, at the upper comers of canyon the peak ground accelerations greatly increase; whereas the peak ground accelerations diminish at the bottom comers of canyon. Under oblique incident SV waves, the shaking of the canyon slope perpendicular to the incidence direction is much more severe than that of the opposite side of canyon. And the ground surface has been characterized by larger deformations in the case of oblique incident waves. It is also concluded that the low piers and frame of the continuous rigid frame bridge ape more sensitive to the multi-support seismic excitations than the flexible high piers. The canyon topography as well as the oblique incidence of the waves brings the continuous rigid frame bridge severe responses, which should be taken into account in bridge design.
基金Key Project of Scientific and Technological Development Planning of Beijing Education Commission (kz200710009005)National Natural Science Foundation of China (50678001)
文摘Seismic ground motions of two neighboring mountains and the free surface between them are calculated under the SV seismic waves with three different incident angles. The results are then taken as the inputs of multi-point seismic excitations for the foundation of a long-span bridge built over the valley in the analysis considering the integrated influence of traveling wave and topography. On the basis of a dynamic analytical method, a finite element model is created for the seismic responses of a four-span rigid-frame bridge of 440 m. The pier-top displacement and the pier-bottom internal force of the bridge are calculated. Then the results are compared with those considering traveling-wave effect only. The conclusions can serve as a seismic design reference for the structures located on the complex mountain topography.
文摘在煤矿技术致因事故率逐年下降、人因事故率却高居不下的背景下,煤矿安全标识作为安全信息的重要载体,如何影响矿工的安全认知和决策过程成为信息时代重要的研究内容。为探索安全标识有效性影响机理,降低煤矿安全事故发生概率,结合框架效应,借助ErgoLAB Experiment平台和Tobii Pro Nano眼动仪收集了30名被试的试验数据,研究在不同作业情境(高风险或低风险)下,不同损益框架的煤矿安全标识对矿工再认记忆任务和眼动行为的影响。结果表明:高风险作业情境及使用损失框架展示的安全标识能显著提高被试的再认记忆正确率;在低风险作业情境的安全标识设计中,可以突出潜在风险和损失,以吸引矿工有限的安全注意力。研究结果可为安全标识优化设计提供证据和参考,有助于提高煤矿的安全生产水平。
