The Haicheng earthquake （Ms 7.3） occurred in Liaoning Province （39°N-43°N, 120°E-126°E ）, China on February 4, 1975. The mortality rate was only 0.02% owing to the first timely and accurate pre...The Haicheng earthquake （Ms 7.3） occurred in Liaoning Province （39°N-43°N, 120°E-126°E ）, China on February 4, 1975. The mortality rate was only 0.02% owing to the first timely and accurate prediction, although the area affected by the earthquake was 9200 km^2 and covered cities with a population density of 1000 p/km^2. In this study, the double- difference （DD） tomography method was used to obtain high-resolution three-dimensional （3D） P- and S-wave velocity （Vp and Vs） structures and Vp/Vs as well as the earthquake locations. Tomography results suggest that velocity structure at shallow depth coincides well with topography and sediment thickness. The earthquake locations form a northwest-striking zone associated with the Jinzhou（JZ） Fault and a northeast-striking zone associated with the Haichenghe-Dayanghe （HD） Fault, and suggest that the JZ Fault consists of three faults and the Ms 7.3 Haicheng earthquake originated at the intersection of the JZ and the Faults. Low- velocity zones （LVZs） with low Vp/Vs are observed at 15-20 km depth beneath the Haicheng （HC） region. We interpret the LVZs in the middle crust as regions of fluids, suggesting rock dehydration at high temperatures. The LVZs and low Vp/Vs in the upper crust are attributed to groundwater-filled cracks and pores. We believe that large crustal earthquakes in this area are caused by the combination of faulting and fluid movement in the middle crust.展开更多
For non-catalytic gas-solid reaction, it is desirable to match the mean residence time （MRT） of particles and complete conversion time （tc） in a fluidized bed. In this study, the MRT differences （MRT ratios） bet...For non-catalytic gas-solid reaction, it is desirable to match the mean residence time （MRT） of particles and complete conversion time （tc） in a fluidized bed. In this study, the MRT differences （MRT ratios） between the coarse particles and the fine particles were investigated in a continuous fluidized bed with a side exit by varying the superficial gas velocity, feed composition and particle size ratio, The results show that the MRT ratio increases firstly and then decreases with increasing the gas velocity. By controlling the gas velocity and the feed composi tion of coarse particles, the MRT ratio can be modulated from 1.8 to 10.5 at the gas velocity of 1.0 m-s -1 for the binary mixture with the size ratio of 2.2. The MRT ratio can reach to - 12 at the gas velocity of 1.2 m. s for the particle size ratio of 3.3. The present study has endeavored to obtain fundamental data for an effective plant operation to meet the need of synchronously complete conversion of particles with different sizes during the film diffusion controlling reaction.展开更多
This research focused on a prediction of compressive strength in porous concrete based on the ratio of air-entrained agents in the concrete slab using nondestructive testing methods such as the Impact Echo （IE） meth...This research focused on a prediction of compressive strength in porous concrete based on the ratio of air-entrained agents in the concrete slab using nondestructive testing methods such as the Impact Echo （IE） method, Spectral Analysis of Surface Wave （SASW） method and Free-Free Resonance （FFR） test. The method that best predicts the strength of the concrete slab can be derived from a relationship between compressive strengths and stress wave velocities. Concrete slab specimens of varying air content, were formed with a mix ratio of air-entrained agent of 0%, 0.15%, 0.3%, 0.7% and 1.5% by weight. These slabs were tested and analyzed to measure the stress wave velocities in order to develop a correlation with compressive strengths. The plot between the stress waves and compressive strengths showed a stiffslope up to an air ratio of 4% with a less steep slope beyond this point. In the process of predicting the compressive strength of concrete slab specimens, the prediction of compressive strength based on the compression wave velocity caused an average error of 4.9% in the compression wave velocity, and the prediction of compressive strength based on the surface wave velocity caused an average error of 2.2% in the surface wave velocity.展开更多
基金supported by the National Natural Science Foundation of China(Grants Nos.41430322 and 41474030)the National Key Research and Development Project of China(Grants No.2016YFC0600301)
文摘The Haicheng earthquake （Ms 7.3） occurred in Liaoning Province （39°N-43°N, 120°E-126°E ）, China on February 4, 1975. The mortality rate was only 0.02% owing to the first timely and accurate prediction, although the area affected by the earthquake was 9200 km^2 and covered cities with a population density of 1000 p/km^2. In this study, the double- difference （DD） tomography method was used to obtain high-resolution three-dimensional （3D） P- and S-wave velocity （Vp and Vs） structures and Vp/Vs as well as the earthquake locations. Tomography results suggest that velocity structure at shallow depth coincides well with topography and sediment thickness. The earthquake locations form a northwest-striking zone associated with the Jinzhou（JZ） Fault and a northeast-striking zone associated with the Haichenghe-Dayanghe （HD） Fault, and suggest that the JZ Fault consists of three faults and the Ms 7.3 Haicheng earthquake originated at the intersection of the JZ and the Faults. Low- velocity zones （LVZs） with low Vp/Vs are observed at 15-20 km depth beneath the Haicheng （HC） region. We interpret the LVZs in the middle crust as regions of fluids, suggesting rock dehydration at high temperatures. The LVZs and low Vp/Vs in the upper crust are attributed to groundwater-filled cracks and pores. We believe that large crustal earthquakes in this area are caused by the combination of faulting and fluid movement in the middle crust.
基金Supported by the China National Funds for Distinguished Young Scientists(21325628)National Natural Science Foundation of China(91334108)the State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences(MPCS-2012-A-02 and MPCS-2014-A-03)
文摘For non-catalytic gas-solid reaction, it is desirable to match the mean residence time （MRT） of particles and complete conversion time （tc） in a fluidized bed. In this study, the MRT differences （MRT ratios） between the coarse particles and the fine particles were investigated in a continuous fluidized bed with a side exit by varying the superficial gas velocity, feed composition and particle size ratio, The results show that the MRT ratio increases firstly and then decreases with increasing the gas velocity. By controlling the gas velocity and the feed composi tion of coarse particles, the MRT ratio can be modulated from 1.8 to 10.5 at the gas velocity of 1.0 m-s -1 for the binary mixture with the size ratio of 2.2. The MRT ratio can reach to - 12 at the gas velocity of 1.2 m. s for the particle size ratio of 3.3. The present study has endeavored to obtain fundamental data for an effective plant operation to meet the need of synchronously complete conversion of particles with different sizes during the film diffusion controlling reaction.
文摘This research focused on a prediction of compressive strength in porous concrete based on the ratio of air-entrained agents in the concrete slab using nondestructive testing methods such as the Impact Echo （IE） method, Spectral Analysis of Surface Wave （SASW） method and Free-Free Resonance （FFR） test. The method that best predicts the strength of the concrete slab can be derived from a relationship between compressive strengths and stress wave velocities. Concrete slab specimens of varying air content, were formed with a mix ratio of air-entrained agent of 0%, 0.15%, 0.3%, 0.7% and 1.5% by weight. These slabs were tested and analyzed to measure the stress wave velocities in order to develop a correlation with compressive strengths. The plot between the stress waves and compressive strengths showed a stiffslope up to an air ratio of 4% with a less steep slope beyond this point. In the process of predicting the compressive strength of concrete slab specimens, the prediction of compressive strength based on the compression wave velocity caused an average error of 4.9% in the compression wave velocity, and the prediction of compressive strength based on the surface wave velocity caused an average error of 2.2% in the surface wave velocity.
