Two kinds of corner effects existing in double-gate （DG） and gate-all-around （GAA） MOSFETs have been investigated by three-dimensional （3D） and two-dimensional （2D） simulations. It is found that the corner eff...Two kinds of corner effects existing in double-gate （DG） and gate-all-around （GAA） MOSFETs have been investigated by three-dimensional （3D） and two-dimensional （2D） simulations. It is found that the corner effect caused by conterminous gates, which is usually deemed to deteriorate the transistor performance, does not always play a negative role in GAA transistors. It can suppress the leakage current of transistors with low channel doping, though it will enhance the leakage current at high channel doping. The study of another kind of corner effect, which exists in the corner at the bottom of the silicon pillar of DG/GAA vertical MOSFETs, indicates that the D-top structure with drain on the top of the device pillar of vertical transistor shows great advantage due to lower leakage current and better DIBL （drain induced barrier lowering） effect immunity than the S-top structure with source on the top of the device pillar. Therefore the D-top structure is more suitable when the requirement in leakage current and short channel character is critical.展开更多
This paper draws lessons learnt from a comprehensive case study in overconsolidated clay. Apart from the introduction of the case study, including field measurements, the paper draws on the observations and a three-di...This paper draws lessons learnt from a comprehensive case study in overconsolidated clay. Apart from the introduction of the case study, including field measurements, the paper draws on the observations and a three-dimensional（3 D） numerical analysis to discuss the implications of observations in the application of the observational method（OM） in the context of the requirements of EUROCODE 7（EC7）.In particular, we focus on corner effects and time-dependent movements and provide initial guidance on how these could be considered. Additionally, we present the validation of a new set of parameters to check that it provides a satisfactory compliance with EC7 as a set of design parameters. All these findings and recommendations are particularly important for those who want to use the OM in similar future projects.展开更多
A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed w...A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.展开更多
The improvement of the characteristics of grooved-gate MOSFETs compared to the planar devices is attributed to the corner effect of the surface potential along the channel. In this paper we propose an analytical model...The improvement of the characteristics of grooved-gate MOSFETs compared to the planar devices is attributed to the corner effect of the surface potential along the channel. In this paper we propose an analytical model of the surface potential distribution based on the solution of two-dimensional Poisson equation in cylindrical coordinates utilizing the cylinder approximation and the structure parameters such as the concave corner θ0. The relationship between the minimum surface potential and the structure parameters is theoretically analysed. Results confirm that the bigger the concave corner, the more obvious the corner effect. The corner effect increases the threshold voltage of the grooved-gate MOSFETs, so the better is the short channel effect （SCE） immunity.展开更多
Many natural creatures have demonstrated unique abilities in directional liquid transport(DLT)for better adapting to the local environment,which,for a long time,have inspired the material fabrication for applications ...Many natural creatures have demonstrated unique abilities in directional liquid transport(DLT)for better adapting to the local environment,which,for a long time,have inspired the material fabrication for applications in microfluidics,self-cleaning,water collection,etc.Recently,DLTs aroused by the corner effect have been witnessed in various natural organisms,where liquid transports/spreads spontaneously along the corner structures in microgrooves,wedges or conical structures driven by micro-/nano-scaled capillary forces without external energy input.Particularly,these DLTs show advantages of ultrahigh speed,continuous proceeding,and/or external controllability.Here,we reviewed recent research advances on the bioinspired DLTs induced by the corner effect,as well as the involved mechanisms and the artificial counterpart materials with various applications.We also introduced some bioinspired materials that are capable of stimulus-responsive DLT under external fields.Finally,we suggested perspectives of the bioinspired DLTs in liquid manipulations.展开更多
This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical modeling.Laboratory tests were conducted to determine the soil parameters used in the modified Cam...This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical modeling.Laboratory tests were conducted to determine the soil parameters used in the modified Cam–Clay(MCC)model.Intelligent field monitoring means were adopted and a three-dimensional model was established.Spatial and temporal effects induced by the excavation are investigated for the deep-large foundation pit in soft soil.Deformation characteristics of the enclosure structure and the surrounding environment throughout the excavation process are presented.The behaviors of diaphragm walls,columns,the maximum wall deflection rate,ground surface settlement,and utility pipelines were focused on and investigated during the whole excavation process.Besides,the axial forces of the internal supports are analyzed.Based on the measured and simulated data,the following main conclusions were obtained:the numerical simulation results are in good agreement with the measured values,which proves the accuracy of the model parameters;the wall and the ground surface showed the maximum displacement increment at stage 9,which was a coupled product of the"creep effect"of the soft soil in Nanjing,China and the"depth effect"of the excavation;as the excavation progressed,the ground settlement changed from a"rising"to a"spoon-shaped"trend,dvm was measured betweenδ_(vm)=0.0686%H andδ_(vm)=0.1488%H;the rebound deformation curve of the pit bottom was corrugated,and the depth of disturbance of the pit bottom after the completion of soil unloading was 2–3 times the excavation depth;the closer the pipeline is to the corner of the pit,the less the excavation process will affect the settlement of the pipeline and the less the obvious pit corner effect will occur;the support strength of the buttress and the longest corner brace should be strengthened during the actual construction process to ensure the stability of the foundation deformation.展开更多
基金Project supported by State Key Fundamental Research Project of China （Grant No 2000036501） and the National Natural Science Foundation of China （Grant No 90207004）.
文摘Two kinds of corner effects existing in double-gate （DG） and gate-all-around （GAA） MOSFETs have been investigated by three-dimensional （3D） and two-dimensional （2D） simulations. It is found that the corner effect caused by conterminous gates, which is usually deemed to deteriorate the transistor performance, does not always play a negative role in GAA transistors. It can suppress the leakage current of transistors with low channel doping, though it will enhance the leakage current at high channel doping. The study of another kind of corner effect, which exists in the corner at the bottom of the silicon pillar of DG/GAA vertical MOSFETs, indicates that the D-top structure with drain on the top of the device pillar of vertical transistor shows great advantage due to lower leakage current and better DIBL （drain induced barrier lowering） effect immunity than the S-top structure with source on the top of the device pillar. Therefore the D-top structure is more suitable when the requirement in leakage current and short channel character is critical.
基金the EPSRC for their funding to undertake this research
文摘This paper draws lessons learnt from a comprehensive case study in overconsolidated clay. Apart from the introduction of the case study, including field measurements, the paper draws on the observations and a three-dimensional（3 D） numerical analysis to discuss the implications of observations in the application of the observational method（OM） in the context of the requirements of EUROCODE 7（EC7）.In particular, we focus on corner effects and time-dependent movements and provide initial guidance on how these could be considered. Additionally, we present the validation of a new set of parameters to check that it provides a satisfactory compliance with EC7 as a set of design parameters. All these findings and recommendations are particularly important for those who want to use the OM in similar future projects.
基金Foundation item： Project（2009-K3-2） supported by the Ministry of Housing and Urban-Rural Development of China
文摘A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.
基金Project supported by the National Natural Science Foundation of China （Grant No 603776024）.
文摘The improvement of the characteristics of grooved-gate MOSFETs compared to the planar devices is attributed to the corner effect of the surface potential along the channel. In this paper we propose an analytical model of the surface potential distribution based on the solution of two-dimensional Poisson equation in cylindrical coordinates utilizing the cylinder approximation and the structure parameters such as the concave corner θ0. The relationship between the minimum surface potential and the structure parameters is theoretically analysed. Results confirm that the bigger the concave corner, the more obvious the corner effect. The corner effect increases the threshold voltage of the grooved-gate MOSFETs, so the better is the short channel effect （SCE） immunity.
基金supported by the National Key R&D Program of China(No.2018YFA0704801)the National Natural Science Foundation of China for Distinguished Young Scholar(No.22125201)the National Natural Science Foundation of China(Nos.21872002 and 22105013).
文摘Many natural creatures have demonstrated unique abilities in directional liquid transport(DLT)for better adapting to the local environment,which,for a long time,have inspired the material fabrication for applications in microfluidics,self-cleaning,water collection,etc.Recently,DLTs aroused by the corner effect have been witnessed in various natural organisms,where liquid transports/spreads spontaneously along the corner structures in microgrooves,wedges or conical structures driven by micro-/nano-scaled capillary forces without external energy input.Particularly,these DLTs show advantages of ultrahigh speed,continuous proceeding,and/or external controllability.Here,we reviewed recent research advances on the bioinspired DLTs induced by the corner effect,as well as the involved mechanisms and the artificial counterpart materials with various applications.We also introduced some bioinspired materials that are capable of stimulus-responsive DLT under external fields.Finally,we suggested perspectives of the bioinspired DLTs in liquid manipulations.
基金financial support provided by Beijing Natural Science Foundation(Grant No.8222005)the National Natural Science Foundation of China(Grant No.51978018)Science and Technology Funding Scheme for Three Companies of China Construction Bureau Ⅱ(No.CSCEC2b3c-2021-K-65).
文摘This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical modeling.Laboratory tests were conducted to determine the soil parameters used in the modified Cam–Clay(MCC)model.Intelligent field monitoring means were adopted and a three-dimensional model was established.Spatial and temporal effects induced by the excavation are investigated for the deep-large foundation pit in soft soil.Deformation characteristics of the enclosure structure and the surrounding environment throughout the excavation process are presented.The behaviors of diaphragm walls,columns,the maximum wall deflection rate,ground surface settlement,and utility pipelines were focused on and investigated during the whole excavation process.Besides,the axial forces of the internal supports are analyzed.Based on the measured and simulated data,the following main conclusions were obtained:the numerical simulation results are in good agreement with the measured values,which proves the accuracy of the model parameters;the wall and the ground surface showed the maximum displacement increment at stage 9,which was a coupled product of the"creep effect"of the soft soil in Nanjing,China and the"depth effect"of the excavation;as the excavation progressed,the ground settlement changed from a"rising"to a"spoon-shaped"trend,dvm was measured betweenδ_(vm)=0.0686%H andδ_(vm)=0.1488%H;the rebound deformation curve of the pit bottom was corrugated,and the depth of disturbance of the pit bottom after the completion of soil unloading was 2–3 times the excavation depth;the closer the pipeline is to the corner of the pit,the less the excavation process will affect the settlement of the pipeline and the less the obvious pit corner effect will occur;the support strength of the buttress and the longest corner brace should be strengthened during the actual construction process to ensure the stability of the foundation deformation.
