Soil dynamic parameters,including dynamic shear modulus ratio and damping ratio,have important effects on the results of layered soil earthquake response. In this paper,the mean parameter values of silty clay in diffe...Soil dynamic parameters,including dynamic shear modulus ratio and damping ratio,have important effects on the results of layered soil earthquake response. In this paper,the mean parameter values of silty clay in different depths are obtained after statistical analysis of the experimental soil dynamic data from 20 recent site seismic safety evaluation reports in the Beijing area. Furthermore,based on two typical engineering sites,the influence of four different soil dynamic parameters,the statistic mean values,experimental values, values recommended by Yuan Xiaoming,and the values recommended in the code for seismic safety evaluation of engineering sites( DB001-94) are analyzed. The result shows that mean statistical values are applicable to seismic safety evaluation work in the Beijing area,especially for some inter-layered silty clays whose undisturbed soil samples are hard to obtain.展开更多
According to the Chinese GB50011-2001 code and the recommended provisions of FEMA-NEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site...According to the Chinese GB50011-2001 code and the recommended provisions of FEMA-NEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site on the Yantai seacoast. The site seismic ground motion effect is analyzed and the influence of the coastal soil on design ground motion parameters is discussed. The results show that the brief site classification can not represent the real conditions of a soft soil site; the soft soil on the coast has a remarkable impact on the magnitude and spectrum of ground motion acceleration. The magnification on peak acceleration is bigger, however, due to the nonlinear deformation of the soil. The magnification is reduced nonlinearly with the increase of input ground motion; the spectrum is broadened and the characteristic period elongated on the soft soil site.展开更多
Conventional transcutaneous electrical nerve stimulation(cTENS),which uses a modulated square waveform as stimuli,has been generally used in testing and eliciting artificial tactile perception in forearm amputees.Howe...Conventional transcutaneous electrical nerve stimulation(cTENS),which uses a modulated square waveform as stimuli,has been generally used in testing and eliciting artificial tactile perception in forearm amputees.However,a novel neuromorphic TENS(nTENS)model based on neural signals has been largely ignored.In this study,we further explore the effect of nTENS patterns to elicit tactile perception in forearm amputees.Four forearm amputees were recruited to test discriminate tactile perception elicited by different TENS patterns with electroencephalography(EEG)recording at the following four stimulated sites:the index finger and the little finger on both phantom and real sides.Finally,we compared the results of cortical networks in six frequency bands at different stimulated sites between forearm amputees and able-bodied subjects.Behavioral results suggested that n TENS patterns required a lower electric charge at each stimulated site than cTENS patterns.And forearm amputees required a higher intensity in each TENS pattern than able-bodied subjects.Moreover,amputees showed a lower clustering coefficient(aCP),global efficiency(aEG),local efficiency(aEL),and a longer path length(aLP)than able-bodied subjects in all six frequency bands when stimulation was accessed.Specifically,the SMU pattern showed a higher functional network efficiency in real fingers than at phantom sites in theta,alpha,and high gamma bands.This study highlighted the characteristics of n TENS patterns in eliciting tactile perception among forearm amputees,which provided insights into evaluating the neural mechanism of tactile information processing in forearm amputees and building tactile perceptual systems for sensory rehabilitation.展开更多
TiN,platinum (Pt) black and iridium oxide are introduced to the stimulating sites to improve the performance of the flexible electrode.Low temperature process is used to fabricate the modifying films.TiN is coated on ...TiN,platinum (Pt) black and iridium oxide are introduced to the stimulating sites to improve the performance of the flexible electrode.Low temperature process is used to fabricate the modifying films.TiN is coated on the gold sites by magnetron sputtering while platinum black and iridium oxide are coated by electroplating and electrodeposition,respectively.The im-pedance of the electrode decreases dramatically after modification.The combined analysis of surface morphology and cyclic voltammograms (CV) in phosphate buffer saline (PBS) solution indicates that the modified electrode sites have larger elec-trode-electrolyte capacitance and smaller faradic resistance than unmodified sites,thus they have smaller electrochemical im-pedances.展开更多
Silicon-based planar neuroprobes are composed of silicon substrate,conducting layer,and insulation layers of SiO 2 or SiN membrane.The insulation layer is very important because it affects many key parameters of neupr...Silicon-based planar neuroprobes are composed of silicon substrate,conducting layer,and insulation layers of SiO 2 or SiN membrane.The insulation layer is very important because it affects many key parameters of neuprobes,like impedance,SNR(signal noise ratio),reliability,etc.Monolayer membrane of SiO 2 or SiN are not good choices for insulation layer,since defects and residual stress in these layers can induce bad passivation.In this paper a composite insulation structure is studied,with thermal SiO 2 as the lower insulation layer and with multilayer membrane composed of PECVD SiO 2 and SiN as the upper insulation layer.This structure not only solves the problem of residual stress but also ensures a good probe passivation.So it's a good choice for insulation layer of neuroprobes.展开更多
基金sponsored jointly by the Research Grants from Institute of Crustal Dynamics,CEA(NO. ZDJ2007-7)the 2007 Special Research Project 8-50 of the Department of Finance
文摘Soil dynamic parameters,including dynamic shear modulus ratio and damping ratio,have important effects on the results of layered soil earthquake response. In this paper,the mean parameter values of silty clay in different depths are obtained after statistical analysis of the experimental soil dynamic data from 20 recent site seismic safety evaluation reports in the Beijing area. Furthermore,based on two typical engineering sites,the influence of four different soil dynamic parameters,the statistic mean values,experimental values, values recommended by Yuan Xiaoming,and the values recommended in the code for seismic safety evaluation of engineering sites( DB001-94) are analyzed. The result shows that mean statistical values are applicable to seismic safety evaluation work in the Beijing area,especially for some inter-layered silty clays whose undisturbed soil samples are hard to obtain.
文摘According to the Chinese GB50011-2001 code and the recommended provisions of FEMA-NEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site on the Yantai seacoast. The site seismic ground motion effect is analyzed and the influence of the coastal soil on design ground motion parameters is discussed. The results show that the brief site classification can not represent the real conditions of a soft soil site; the soft soil on the coast has a remarkable impact on the magnitude and spectrum of ground motion acceleration. The magnification on peak acceleration is bigger, however, due to the nonlinear deformation of the soil. The magnification is reduced nonlinearly with the increase of input ground motion; the spectrum is broadened and the characteristic period elongated on the soft soil site.
基金supported by the National Key R&D Program of China(Grant No.2018YFB1307301)。
文摘Conventional transcutaneous electrical nerve stimulation(cTENS),which uses a modulated square waveform as stimuli,has been generally used in testing and eliciting artificial tactile perception in forearm amputees.However,a novel neuromorphic TENS(nTENS)model based on neural signals has been largely ignored.In this study,we further explore the effect of nTENS patterns to elicit tactile perception in forearm amputees.Four forearm amputees were recruited to test discriminate tactile perception elicited by different TENS patterns with electroencephalography(EEG)recording at the following four stimulated sites:the index finger and the little finger on both phantom and real sides.Finally,we compared the results of cortical networks in six frequency bands at different stimulated sites between forearm amputees and able-bodied subjects.Behavioral results suggested that n TENS patterns required a lower electric charge at each stimulated site than cTENS patterns.And forearm amputees required a higher intensity in each TENS pattern than able-bodied subjects.Moreover,amputees showed a lower clustering coefficient(aCP),global efficiency(aEG),local efficiency(aEL),and a longer path length(aLP)than able-bodied subjects in all six frequency bands when stimulation was accessed.Specifically,the SMU pattern showed a higher functional network efficiency in real fingers than at phantom sites in theta,alpha,and high gamma bands.This study highlighted the characteristics of n TENS patterns in eliciting tactile perception among forearm amputees,which provided insights into evaluating the neural mechanism of tactile information processing in forearm amputees and building tactile perceptual systems for sensory rehabilitation.
基金supported by the Major National Scientific Research Plan (Grant Nos. 2011CB933203, 2011CB933102)National Natural Science Foundation of China (Grant Nos. 61036002, 60877035, 31070965)
文摘TiN,platinum (Pt) black and iridium oxide are introduced to the stimulating sites to improve the performance of the flexible electrode.Low temperature process is used to fabricate the modifying films.TiN is coated on the gold sites by magnetron sputtering while platinum black and iridium oxide are coated by electroplating and electrodeposition,respectively.The im-pedance of the electrode decreases dramatically after modification.The combined analysis of surface morphology and cyclic voltammograms (CV) in phosphate buffer saline (PBS) solution indicates that the modified electrode sites have larger elec-trode-electrolyte capacitance and smaller faradic resistance than unmodified sites,thus they have smaller electrochemical im-pedances.
文摘Silicon-based planar neuroprobes are composed of silicon substrate,conducting layer,and insulation layers of SiO 2 or SiN membrane.The insulation layer is very important because it affects many key parameters of neuprobes,like impedance,SNR(signal noise ratio),reliability,etc.Monolayer membrane of SiO 2 or SiN are not good choices for insulation layer,since defects and residual stress in these layers can induce bad passivation.In this paper a composite insulation structure is studied,with thermal SiO 2 as the lower insulation layer and with multilayer membrane composed of PECVD SiO 2 and SiN as the upper insulation layer.This structure not only solves the problem of residual stress but also ensures a good probe passivation.So it's a good choice for insulation layer of neuroprobes.
