In this study, the aerodynamic characteristics of tall buildings with corner modifications (e.g., local wind force coefficients, mean pressure distributions, normalized power spectrum density, and extreme local pressu...In this study, the aerodynamic characteristics of tall buildings with corner modifications (e.g., local wind force coefficients, mean pressure distributions, normalized power spectrum density, and extreme local pressure) were examined. Wind tunnel experiments were conducted to measure the wind pressures on building models with different heights and recessed corners of different ratios. At a wind direction of a = 0° (i.e., wind blowing on the front of a building), corner modifications effectively reduced wind forces in all cases. Specifically, small corner modification ratios reduced wind forces more effectively than their larger counterparts. However, corner modifications resulted in extreme local pressure on building surfaces. In addition, for small corner modification ratios, the probability of extreme local pressure occurring at a = 0° was high. This probability was also high for large corner modification ratios at a = 15° (i.e., wind blowing slightly obliquely on the front of a building) because wind blowing obliquely creates substantial vortex shedding on one side surface and extreme negative pressure over one building side surface. Results of computational fluid dynamic modeling were adopted to determine details of the aerodynamic characteristics of tall buildings with corner modifications.展开更多
The numerical simulation results utilizing the Peridynamics(PD)method reveal that the initial crack and crack propagation of the tunnel concrete lining structure agree with the experimental data compared to the Japane...The numerical simulation results utilizing the Peridynamics(PD)method reveal that the initial crack and crack propagation of the tunnel concrete lining structure agree with the experimental data compared to the Japanese prototype lining test.The load structure model takes into account the cracking process and distribution of the lining segment under the influence of local bias pressure and lining thickness.In addition,the influence of preset cracks and lining section formon the crack propagation of the concrete lining model is studied.This study evaluates the stability and sustainability of tunnel structure by the Peridynamics method,which provides a reference for the analysis of the causes of lining cracks,and also lays a foundation for the prevention,reinforcement and repair of tunnel lining cracks.展开更多
The first way to identify the needle in relation to the peripheral nerve W. Halsted and R. Hall in 1884 performed the first regional blockade (using direct visualization). However, Vassily von Anrep was a few months e...The first way to identify the needle in relation to the peripheral nerve W. Halsted and R. Hall in 1884 performed the first regional blockade (using direct visualization). However, Vassily von Anrep was a few months earlier described the blockade of the peripheral nerve by anatomical landmarks. In 1912, the blockade of the brachial plexus was first performed using electrical stimulation, but this technique has been widely used only since 1962. The most popular way to identify the needle relative to the nerve at the moment remains US guidance. A promising direction may be optical coherence tomography. But this method is under development. In the last decade, a method for determining the pressure of a local anesthetic has been introduced into practice to determine the position of the needle relative to the nerve.展开更多
In this paper,local unstable metric entropy,local unstable topological entropy and local unstable pressure for partially hyperbolic endomorphisms are introduced and investigated.Specially,two variational principles co...In this paper,local unstable metric entropy,local unstable topological entropy and local unstable pressure for partially hyperbolic endomorphisms are introduced and investigated.Specially,two variational principles concerning relationships among the above mentioned numbers are formulated.展开更多
基金This work was supported by Korea Research Fellowship Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT。
文摘In this study, the aerodynamic characteristics of tall buildings with corner modifications (e.g., local wind force coefficients, mean pressure distributions, normalized power spectrum density, and extreme local pressure) were examined. Wind tunnel experiments were conducted to measure the wind pressures on building models with different heights and recessed corners of different ratios. At a wind direction of a = 0° (i.e., wind blowing on the front of a building), corner modifications effectively reduced wind forces in all cases. Specifically, small corner modification ratios reduced wind forces more effectively than their larger counterparts. However, corner modifications resulted in extreme local pressure on building surfaces. In addition, for small corner modification ratios, the probability of extreme local pressure occurring at a = 0° was high. This probability was also high for large corner modification ratios at a = 15° (i.e., wind blowing slightly obliquely on the front of a building) because wind blowing obliquely creates substantial vortex shedding on one side surface and extreme negative pressure over one building side surface. Results of computational fluid dynamic modeling were adopted to determine details of the aerodynamic characteristics of tall buildings with corner modifications.
基金supported by the National Natural Science Foundation of China (52079128).
文摘The numerical simulation results utilizing the Peridynamics(PD)method reveal that the initial crack and crack propagation of the tunnel concrete lining structure agree with the experimental data compared to the Japanese prototype lining test.The load structure model takes into account the cracking process and distribution of the lining segment under the influence of local bias pressure and lining thickness.In addition,the influence of preset cracks and lining section formon the crack propagation of the concrete lining model is studied.This study evaluates the stability and sustainability of tunnel structure by the Peridynamics method,which provides a reference for the analysis of the causes of lining cracks,and also lays a foundation for the prevention,reinforcement and repair of tunnel lining cracks.
文摘The first way to identify the needle in relation to the peripheral nerve W. Halsted and R. Hall in 1884 performed the first regional blockade (using direct visualization). However, Vassily von Anrep was a few months earlier described the blockade of the peripheral nerve by anatomical landmarks. In 1912, the blockade of the brachial plexus was first performed using electrical stimulation, but this technique has been widely used only since 1962. The most popular way to identify the needle relative to the nerve at the moment remains US guidance. A promising direction may be optical coherence tomography. But this method is under development. In the last decade, a method for determining the pressure of a local anesthetic has been introduced into practice to determine the position of the needle relative to the nerve.
基金supported by the National Natural Science Foundation of China (Nos. 11771118,11801336, 12171400)the Innovation Fund Designated for Graduate Students of Hebei Province (No.CXZZBS2018101)+1 种基金China Scholarship Council (CSC for short)China Postdoctoral Science Foundation (No. 2021M691889).
文摘In this paper,local unstable metric entropy,local unstable topological entropy and local unstable pressure for partially hyperbolic endomorphisms are introduced and investigated.Specially,two variational principles concerning relationships among the above mentioned numbers are formulated.