There was an earthquake swarm of two major events of MS6.3 and MS5.8 on the Xianshuihe fault in November, 2014. The two major earthquakes are both strike-slip events with aftershock zone along NW direction.We have ana...There was an earthquake swarm of two major events of MS6.3 and MS5.8 on the Xianshuihe fault in November, 2014. The two major earthquakes are both strike-slip events with aftershock zone along NW direction.We have analyzed the characteristics of this earthquake sequence. The b value and the h value show the significant variations in different periods before and after the MS5.8earthquake. Based on the data of historical earthquakes, we also illustrated the moderate-strong seismic activity on the Xianshuihe fault. The Kangding earthquake swarm manifests the seismic activity on Xianshuihe fault may be in the late seismic active period. The occurrence of the Kangding earthquake may be an adjustment of the strong earthquakes on the Xianshuihe fault. The Coulomb failure stress changes caused by the historical earthquakes were also given in this article. The results indicate that the earthquake swarm was encouraged by the historical earthquakes since1893, especially by the MS7.5 Kangding earthquake in1955. The Coulomb failure stress changes also shows the subsequent MS5.8 earthquake was triggered by the MS6.3earthquake.展开更多
Objective To explore the influence of stress induced increased sympathetic nerve activity on cardiomyocyte apoptosis and on the development of congestive heart failure. Methods 45 male, 16 week old spontaneously hy...Objective To explore the influence of stress induced increased sympathetic nerve activity on cardiomyocyte apoptosis and on the development of congestive heart failure. Methods 45 male, 16 week old spontaneously hypertensive rats (SHRs) were studied, in which 6 as controls. After the 6 controlled SHRs were examined by echocardiography, they were anesthetized and killed by decapitation. The other 39 were divided into the stress group (n=20) and the control group (n=19), and both groups were observed from 16 week old to 36 week old. In the stress group, binding-stress model was used. Till 36 week, all animals were echocardiographied, weighed and killed as described above. Cardiac bcl 2 and bax protein were quantified by western blot. Circulating catecholamine and angiotensin II (Ang II) were detected by radioimmunoasssy. Results Left ventricular volume (P< 0.05), left ventricular mass (P< 0.05) and the ratio of ventricular mass to body weight were higher in 36 week than those of the 16 week SHRs, whereas the volumes of eject fraction (EF) manifested the trend of decline, P< 0.05, binding stress for 20 weeks made this trend significantly, P< 0.05. With the increase of age, the serum norepinephrine (NE), epinephrine (E) and Ang II increased, suggesting that the binding-stress triggered the activity of central sympathetic nerve system. The cardiac bcl 2 protein was higher in 36 week than 16 week, P >0.05, whereas the bax protein increased significantly with the increase of age, P< 0.05, and so was the ratio of bax to bcl 2, P< 0.05. Conclusions The model of binding stress can effectively activate central sympathetic system, thus and mimic the neuroendocrine states. From 16 to 36 week, the process of cardiac apoptosis aggravated and the increased sympathetic activity would exacerbate rather than relieve this trend.展开更多
Trapdoor stability has been widely studied by many researchers in the field of tunneling engineering.A general question being fre-quently asked is that why most sinkholes have a near-perfect circular shape on the grou...Trapdoor stability has been widely studied by many researchers in the field of tunneling engineering.A general question being fre-quently asked is that why most sinkholes have a near-perfect circular shape on the ground surface.This could be possibly explained by the current numerical study using finite element limit analysis under axisymmetric condition,where upper and lower bound solutions of active circular trapdoors are determined.The failure study of sinkholes and the associated failure mechanisms in this paper are for non-homogeneous clay with a linear increase of strength with depth under various cover depth ratios and dimensionless strength gra-dients.A design equation for predicting the stability solutions is also developed based on the novel three dimensional solutions using axisymmetry.展开更多
Several environmental changes can induce an underground hole,leading to failures of non-ground infrastructure,such as pavements.Under a continued overload of traffic action on the pavement,the hole can potentially col...Several environmental changes can induce an underground hole,leading to failures of non-ground infrastructure,such as pavements.Under a continued overload of traffic action on the pavement,the hole can potentially collapse,leading to creation of potholes.This phenomenon is commonly known as a trapdoor problem.Even though there are several previous works considering this problem,the stability solutions of trapdoors in two-layered soils have not yet been studied.To estimate the undrained stability of active trapdoors in two-layered clays under plane strain conditions,numerical solutions based on the finite element method have been developed.The influence parameters include the coverage depth of the trapdoor,and the thickness and undrained shear strength of the clay layers.The effects of these parameters on the stability of active trapdoors as well as their associated failure mechanisms are examined and discussed in this paper.The solutions are presented in the form of dimensionless charts that can be used for the design of trapdoor systems in two-layered clays with different thicknesses and undrained shear strengths.展开更多
基金supported by Spark Program of Earthquake Science of China under Grant No.XH15047YNational Natural Science Foundation of China under Grant No.41274062
文摘There was an earthquake swarm of two major events of MS6.3 and MS5.8 on the Xianshuihe fault in November, 2014. The two major earthquakes are both strike-slip events with aftershock zone along NW direction.We have analyzed the characteristics of this earthquake sequence. The b value and the h value show the significant variations in different periods before and after the MS5.8earthquake. Based on the data of historical earthquakes, we also illustrated the moderate-strong seismic activity on the Xianshuihe fault. The Kangding earthquake swarm manifests the seismic activity on Xianshuihe fault may be in the late seismic active period. The occurrence of the Kangding earthquake may be an adjustment of the strong earthquakes on the Xianshuihe fault. The Coulomb failure stress changes caused by the historical earthquakes were also given in this article. The results indicate that the earthquake swarm was encouraged by the historical earthquakes since1893, especially by the MS7.5 Kangding earthquake in1955. The Coulomb failure stress changes also shows the subsequent MS5.8 earthquake was triggered by the MS6.3earthquake.
文摘Objective To explore the influence of stress induced increased sympathetic nerve activity on cardiomyocyte apoptosis and on the development of congestive heart failure. Methods 45 male, 16 week old spontaneously hypertensive rats (SHRs) were studied, in which 6 as controls. After the 6 controlled SHRs were examined by echocardiography, they were anesthetized and killed by decapitation. The other 39 were divided into the stress group (n=20) and the control group (n=19), and both groups were observed from 16 week old to 36 week old. In the stress group, binding-stress model was used. Till 36 week, all animals were echocardiographied, weighed and killed as described above. Cardiac bcl 2 and bax protein were quantified by western blot. Circulating catecholamine and angiotensin II (Ang II) were detected by radioimmunoasssy. Results Left ventricular volume (P< 0.05), left ventricular mass (P< 0.05) and the ratio of ventricular mass to body weight were higher in 36 week than those of the 16 week SHRs, whereas the volumes of eject fraction (EF) manifested the trend of decline, P< 0.05, binding stress for 20 weeks made this trend significantly, P< 0.05. With the increase of age, the serum norepinephrine (NE), epinephrine (E) and Ang II increased, suggesting that the binding-stress triggered the activity of central sympathetic nerve system. The cardiac bcl 2 protein was higher in 36 week than 16 week, P >0.05, whereas the bax protein increased significantly with the increase of age, P< 0.05, and so was the ratio of bax to bcl 2, P< 0.05. Conclusions The model of binding stress can effectively activate central sympathetic system, thus and mimic the neuroendocrine states. From 16 to 36 week, the process of cardiac apoptosis aggravated and the increased sympathetic activity would exacerbate rather than relieve this trend.
文摘Trapdoor stability has been widely studied by many researchers in the field of tunneling engineering.A general question being fre-quently asked is that why most sinkholes have a near-perfect circular shape on the ground surface.This could be possibly explained by the current numerical study using finite element limit analysis under axisymmetric condition,where upper and lower bound solutions of active circular trapdoors are determined.The failure study of sinkholes and the associated failure mechanisms in this paper are for non-homogeneous clay with a linear increase of strength with depth under various cover depth ratios and dimensionless strength gra-dients.A design equation for predicting the stability solutions is also developed based on the novel three dimensional solutions using axisymmetry.
基金supported by the Thailand Research Fund[Grant no.DBG-6180004]the Ratchadapisek Sompoch Endowment Fund(2020),Chulalongkorn University[763014 Climate Change and Disaster Management Cluster].
文摘Several environmental changes can induce an underground hole,leading to failures of non-ground infrastructure,such as pavements.Under a continued overload of traffic action on the pavement,the hole can potentially collapse,leading to creation of potholes.This phenomenon is commonly known as a trapdoor problem.Even though there are several previous works considering this problem,the stability solutions of trapdoors in two-layered soils have not yet been studied.To estimate the undrained stability of active trapdoors in two-layered clays under plane strain conditions,numerical solutions based on the finite element method have been developed.The influence parameters include the coverage depth of the trapdoor,and the thickness and undrained shear strength of the clay layers.The effects of these parameters on the stability of active trapdoors as well as their associated failure mechanisms are examined and discussed in this paper.The solutions are presented in the form of dimensionless charts that can be used for the design of trapdoor systems in two-layered clays with different thicknesses and undrained shear strengths.
