Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial intelligence.However,great efforts have been devoted to explo...Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial intelligence.However,great efforts have been devoted to exploring biomimetic mechanisms of plasticity simulation in the last few years.Recent progress in various plasticity modulation techniques has pushed the research of synaptic electronics from static plasticity simulation to dynamic plasticity modulation,improving the accuracy of neuromorphic computing and providing strategies for implementing neuromorphic sensing functions.Herein,several fascinating strategies for synap-tic plasticity modulation through chemical techniques,device structure design,and physical signal sensing are reviewed.For chemical techniques,the underly-ing mechanisms for the modification of functional materials were clarified and its effect on the expression of synaptic plasticity was also highlighted.Based on device structure design,the reconfigurable operation of neuromorphic devices was well demonstrated to achieve programmable neuromorphic functions.Besides,integrating the sensory units with neuromorphic processing circuits paved a new way to achieve human-like intelligent perception under the modulation of physical signals such as light,strain,and temperature.Finally,considering that the relevant technology is still in the basic exploration stage,some prospects or development suggestions are put forward to promote the development of neuromorphic devices.展开更多
In endoscopic placement of multiple plastic biliary stents (PBSs),we sometimes experience proximal dislocation of the first PBS at the time of subsequent PBS insertion.We describe the case of a 79-year-old male with o...In endoscopic placement of multiple plastic biliary stents (PBSs),we sometimes experience proximal dislocation of the first PBS at the time of subsequent PBS insertion.We describe the case of a 79-year-old male with obstructive jaundice caused by cholangiocarcinoma who needed to receive multiple PBS placements for management of cholangitis.Although proximal dislocation of the first PBS was observed,we prevented the dislocation via our technique of using guidewire inserted from the distal end of the first PBS to the side hole as the anchor-wire.We could complete this technique only by inserting guidewire through the side hole of the first PBS during the process of releasing the first PBS and pulling out the guidewire and the inner sheath.It did not matter whether the anchor-wire went towards the third portion of the duodenum or the duodenal bulb.Here we introduce this "anchor-wire technique",which is useful for the prevention of PBS proximal dislocation in placing multiple PBSs.展开更多
Objective Tricuspid regurgitation is often associated in patients with congenital heart disease. Significant morbidity and mortality are related to tricuspid valve replacement. Tricuspid valve plasty is still a prefer...Objective Tricuspid regurgitation is often associated in patients with congenital heart disease. Significant morbidity and mortality are related to tricuspid valve replacement. Tricuspid valve plasty is still a preferred choice. This report deals with our surgical experience in using edge-to-edge valve plasty technique to correct severe展开更多
Combining the continuously distributed dislocation technique(DDT)and the von Mises yield criterion,new double-crack and multi-crack models were established.The influences of multi-segment kinked micro-cracks and group...Combining the continuously distributed dislocation technique(DDT)and the von Mises yield criterion,new double-crack and multi-crack models were established.The influences of multi-segment kinked micro-cracks and groups of kinked micro-cracks on the plastic behavior of the macro-crack were investigated.The results show that a smaller kinking angle of the micro-crack enhances its influence on the plastic deformation of the macro-crack,potentially leading to plastic zone fusion.Meanwhile,micro-cracks with smaller kinking angles exert a stronger attracting force on macro-crack growth,facilitating convergence between them.Furthermore,annularly distributed micro-crack groups demonstrate a more pronounced attraction on macro-crack propagation compared to linearly distributed micro-crack groups.The double-crack and multi-crack models established in this paper offer a theoretical framework for analyzing the plastic fracture behavior of metallic materials containing complex kinked cracks.展开更多
In recent years, finite element analyses have increasingly been utilized for slope stability problems. In comparison to limit equilibrium methods, numerical analyses do not require any definition of the failure mechan...In recent years, finite element analyses have increasingly been utilized for slope stability problems. In comparison to limit equilibrium methods, numerical analyses do not require any definition of the failure mechanism a priori and enable the determination of the safety level more accurately. The paper compares the performances of strength reduction finite element analysis(SRFEA) with finite element limit analysis(FELA), whereby the focus is related to non-associated plasticity. Displacement-based finite element analyses using a strength reduction technique suffer from numerical instabilities when using non-associated plasticity, especially when dealing with high friction angles but moderate dilatancy angles. The FELA on the other hand provides rigorous upper and lower bounds of the factor of safety(FoS) but is restricted to associated flow rules. Suggestions to overcome this problem, proposed by Davis(1968), lead to conservative FoSs; therefore, an enhanced procedure has been investigated. When using the modified approach, both the SRFEA and the FELA provide very similar results. Further studies highlight the advantages of using an adaptive mesh refinement to determine FoSs. Additionally, it is shown that the initial stress field does not affect the FoS when using a Mohr-Coulomb failure criterion.展开更多
Based on Illiushin's two hypotheses, a new plastic constitutive equation of integral type is proposed. The deviatoric stress induced by a strain path consists of two parts which vary according to different laws. C...Based on Illiushin's two hypotheses, a new plastic constitutive equation of integral type is proposed. The deviatoric stress induced by a strain path consists of two parts which vary according to different laws. Comparison of theoretical calculation with recent experiments is satisfactory. The present theory is not an endochronic theory.展开更多
This paper analyzes mechnasim of casing failure and collapse by salt formation,discusses cementing techniques of salt zone about casing programme, casing design, preparation of well condition, mud and slurry propertie...This paper analyzes mechnasim of casing failure and collapse by salt formation,discusses cementing techniques of salt zone about casing programme, casing design, preparation of well condition, mud and slurry properties required, cementing technology, and puts forward the measures for solving problems posed when cementing through salt sequences, and illustrates with examples.展开更多
The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three di...The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.展开更多
At first glance, it may appear that martial arts and surgery do not relate to each other at all. However, martial arts and surgery are all one on the path of knowledge and self discovery. Innovations are constantly be...At first glance, it may appear that martial arts and surgery do not relate to each other at all. However, martial arts and surgery are all one on the path of knowledge and self discovery. Innovations are constantly being developed;some techniques stand the test of time while others are relegated to history. Martial arts and surgery have also branched out for example boxing, taekwondo, jujitsu and wrestling for martial arts whereas surgery has branched out to orthopaedics, paediatrics, cardiothoracic and neurosurgery to name a few. Some choose to specialize while others choose to be a generalist. Learning methodologies in martial arts and plastic surgery are similar. Martial arts students are the equivalent of surgical residents, and both have to enroll in a school that prepares them to be practitioners of their respective arts. In the last century, formal martial arts academies and surgical residency training programs have sprung up. The standards and entrance requirements vary from school to school as do training methodology and philosophical concepts. In this article, we seek to analyze Bruce Lee’s martial arts’ philosophy of Jeet Kune Do (JKD) and that how we can apply it to our personal path in Plastic & Reconstructive Surgery.展开更多
目的基于贝叶斯网状Meta分析系统评价不同血管化骨瓣在下颌骨缺损修复重建中的存活率。方法计算机检索PubMed、EBSCO、Scopus、Web of Science、Cochrane Library、WanFang Data和CNKI数据库,搜集与研究目的相关的临床研究,检索时限均...目的基于贝叶斯网状Meta分析系统评价不同血管化骨瓣在下颌骨缺损修复重建中的存活率。方法计算机检索PubMed、EBSCO、Scopus、Web of Science、Cochrane Library、WanFang Data和CNKI数据库,搜集与研究目的相关的临床研究,检索时限均从建库至2024年2月。由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用R软件进行贝叶斯网状Meta分析。结果共纳入24项研究,包括1615名患者。Meta分析结果显示腓骨游离瓣、旋髂深动脉髂骨瓣、肩胛骨瓣及携带桡骨的前臂桡侧皮瓣用于下颌骨重建的术后存活率分别为95.62%、94.09%、98.16%和93.75%。网状Meta分析结果显示各组织瓣术后存活率之间的差异均无统计学意义。结论当前证据表明,不同血管化骨瓣在下颌骨缺损修复重建中的存活率相似。受纳入研究数量和质量的限制,上述结论尚待更多高质量研究予以验证。展开更多
The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solv...The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solving the damage structure analysis of hardened and softened nonlinear material.展开更多
A study is presented for the large deflection dynamic response of rigid- plastic circular plate resting on potential fluid under a rectangular pressure pulse load. By virtue of Hankel integral transform technique,this...A study is presented for the large deflection dynamic response of rigid- plastic circular plate resting on potential fluid under a rectangular pressure pulse load. By virtue of Hankel integral transform technique,this interaction problem is reduced to a problem of dynamic plastic response of the plate in vacuum.The closed-form solutions are derived for both middle and high pressure loads by solving the equations of motion with the large deflection in the range where both bending moments and membrane forces are important.Some numerical results are given.展开更多
Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated....Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated. New modified multi-parameter techniques, developed fromCrisfield's multi-parameter methods, are utilized to solve these nonlinear equations. The numericalperformance of these techniques is compared with the standard Newton-Raphson method (sN-R),Crisfield's single parameter method (C1), Crisfield's two parameter method (C2) and Crisfield'sthree parameter method (C3). The new techniques do not involve additional residual force calculationand require little extra computational effort. In addition, they are more robust and efficient thanother existing acceleration techniques.展开更多
In this paper,the mutual influence of plastic behaviors between kinked macro-crack and kinked micro-crack is analyzed based on the distributed dislocation technique and the dislocation-free zone model.A novel theoreti...In this paper,the mutual influence of plastic behaviors between kinked macro-crack and kinked micro-crack is analyzed based on the distributed dislocation technique and the dislocation-free zone model.A novel theoretical model for the size of the plastic zone is proposed,where the length of the dislocation array calculated in a specific direction is utilized to characterize the size of the plastic zone at the crack tip.The results demonstrate that,compared with the length of the dislocation array distributed along the crack direction,the length of the dislocation array distributed at a certain specific angle can more accurately characterize the plastic zone at the crack tip.When compared with the results of finite element analysis,the relative error is within 0.2%.Within the theoretical framework of this paper,it is considered that when the dislocation array is set at the crack tip and forms an angle of approximately 25°with respect to the horizontal direction,the calculated length of the dislocation array can effectively characterize the size of the plastic zone.The dislocation density increases with the decrease of the kinking angle of the crack.These results are conducive to predicting the plastic and fracture behaviors of materials containing kinked cracks.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.62104017 and 52072204)Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘Manipulating the expression of synaptic plasticity of neuromorphic devices provides fascinating opportunities to develop hardware platforms for artifi-cial intelligence.However,great efforts have been devoted to exploring biomimetic mechanisms of plasticity simulation in the last few years.Recent progress in various plasticity modulation techniques has pushed the research of synaptic electronics from static plasticity simulation to dynamic plasticity modulation,improving the accuracy of neuromorphic computing and providing strategies for implementing neuromorphic sensing functions.Herein,several fascinating strategies for synap-tic plasticity modulation through chemical techniques,device structure design,and physical signal sensing are reviewed.For chemical techniques,the underly-ing mechanisms for the modification of functional materials were clarified and its effect on the expression of synaptic plasticity was also highlighted.Based on device structure design,the reconfigurable operation of neuromorphic devices was well demonstrated to achieve programmable neuromorphic functions.Besides,integrating the sensory units with neuromorphic processing circuits paved a new way to achieve human-like intelligent perception under the modulation of physical signals such as light,strain,and temperature.Finally,considering that the relevant technology is still in the basic exploration stage,some prospects or development suggestions are put forward to promote the development of neuromorphic devices.
文摘In endoscopic placement of multiple plastic biliary stents (PBSs),we sometimes experience proximal dislocation of the first PBS at the time of subsequent PBS insertion.We describe the case of a 79-year-old male with obstructive jaundice caused by cholangiocarcinoma who needed to receive multiple PBS placements for management of cholangitis.Although proximal dislocation of the first PBS was observed,we prevented the dislocation via our technique of using guidewire inserted from the distal end of the first PBS to the side hole as the anchor-wire.We could complete this technique only by inserting guidewire through the side hole of the first PBS during the process of releasing the first PBS and pulling out the guidewire and the inner sheath.It did not matter whether the anchor-wire went towards the third portion of the duodenum or the duodenal bulb.Here we introduce this "anchor-wire technique",which is useful for the prevention of PBS proximal dislocation in placing multiple PBSs.
文摘Objective Tricuspid regurgitation is often associated in patients with congenital heart disease. Significant morbidity and mortality are related to tricuspid valve replacement. Tricuspid valve plasty is still a preferred choice. This report deals with our surgical experience in using edge-to-edge valve plasty technique to correct severe
基金supported by the National Natural Science Foundation of China(Grant No.12393782).
文摘Combining the continuously distributed dislocation technique(DDT)and the von Mises yield criterion,new double-crack and multi-crack models were established.The influences of multi-segment kinked micro-cracks and groups of kinked micro-cracks on the plastic behavior of the macro-crack were investigated.The results show that a smaller kinking angle of the micro-crack enhances its influence on the plastic deformation of the macro-crack,potentially leading to plastic zone fusion.Meanwhile,micro-cracks with smaller kinking angles exert a stronger attracting force on macro-crack growth,facilitating convergence between them.Furthermore,annularly distributed micro-crack groups demonstrate a more pronounced attraction on macro-crack propagation compared to linearly distributed micro-crack groups.The double-crack and multi-crack models established in this paper offer a theoretical framework for analyzing the plastic fracture behavior of metallic materials containing complex kinked cracks.
文摘In recent years, finite element analyses have increasingly been utilized for slope stability problems. In comparison to limit equilibrium methods, numerical analyses do not require any definition of the failure mechanism a priori and enable the determination of the safety level more accurately. The paper compares the performances of strength reduction finite element analysis(SRFEA) with finite element limit analysis(FELA), whereby the focus is related to non-associated plasticity. Displacement-based finite element analyses using a strength reduction technique suffer from numerical instabilities when using non-associated plasticity, especially when dealing with high friction angles but moderate dilatancy angles. The FELA on the other hand provides rigorous upper and lower bounds of the factor of safety(FoS) but is restricted to associated flow rules. Suggestions to overcome this problem, proposed by Davis(1968), lead to conservative FoSs; therefore, an enhanced procedure has been investigated. When using the modified approach, both the SRFEA and the FELA provide very similar results. Further studies highlight the advantages of using an adaptive mesh refinement to determine FoSs. Additionally, it is shown that the initial stress field does not affect the FoS when using a Mohr-Coulomb failure criterion.
文摘Based on Illiushin's two hypotheses, a new plastic constitutive equation of integral type is proposed. The deviatoric stress induced by a strain path consists of two parts which vary according to different laws. Comparison of theoretical calculation with recent experiments is satisfactory. The present theory is not an endochronic theory.
文摘This paper analyzes mechnasim of casing failure and collapse by salt formation,discusses cementing techniques of salt zone about casing programme, casing design, preparation of well condition, mud and slurry properties required, cementing technology, and puts forward the measures for solving problems posed when cementing through salt sequences, and illustrates with examples.
文摘The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.
文摘At first glance, it may appear that martial arts and surgery do not relate to each other at all. However, martial arts and surgery are all one on the path of knowledge and self discovery. Innovations are constantly being developed;some techniques stand the test of time while others are relegated to history. Martial arts and surgery have also branched out for example boxing, taekwondo, jujitsu and wrestling for martial arts whereas surgery has branched out to orthopaedics, paediatrics, cardiothoracic and neurosurgery to name a few. Some choose to specialize while others choose to be a generalist. Learning methodologies in martial arts and plastic surgery are similar. Martial arts students are the equivalent of surgical residents, and both have to enroll in a school that prepares them to be practitioners of their respective arts. In the last century, formal martial arts academies and surgical residency training programs have sprung up. The standards and entrance requirements vary from school to school as do training methodology and philosophical concepts. In this article, we seek to analyze Bruce Lee’s martial arts’ philosophy of Jeet Kune Do (JKD) and that how we can apply it to our personal path in Plastic & Reconstructive Surgery.
文摘目的基于贝叶斯网状Meta分析系统评价不同血管化骨瓣在下颌骨缺损修复重建中的存活率。方法计算机检索PubMed、EBSCO、Scopus、Web of Science、Cochrane Library、WanFang Data和CNKI数据库,搜集与研究目的相关的临床研究,检索时限均从建库至2024年2月。由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用R软件进行贝叶斯网状Meta分析。结果共纳入24项研究,包括1615名患者。Meta分析结果显示腓骨游离瓣、旋髂深动脉髂骨瓣、肩胛骨瓣及携带桡骨的前臂桡侧皮瓣用于下颌骨重建的术后存活率分别为95.62%、94.09%、98.16%和93.75%。网状Meta分析结果显示各组织瓣术后存活率之间的差异均无统计学意义。结论当前证据表明,不同血管化骨瓣在下颌骨缺损修复重建中的存活率相似。受纳入研究数量和质量的限制,上述结论尚待更多高质量研究予以验证。
文摘The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solving the damage structure analysis of hardened and softened nonlinear material.
基金The study is supported by National Natural Science Foundation of China.
文摘A study is presented for the large deflection dynamic response of rigid- plastic circular plate resting on potential fluid under a rectangular pressure pulse load. By virtue of Hankel integral transform technique,this interaction problem is reduced to a problem of dynamic plastic response of the plate in vacuum.The closed-form solutions are derived for both middle and high pressure loads by solving the equations of motion with the large deflection in the range where both bending moments and membrane forces are important.Some numerical results are given.
文摘Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated. New modified multi-parameter techniques, developed fromCrisfield's multi-parameter methods, are utilized to solve these nonlinear equations. The numericalperformance of these techniques is compared with the standard Newton-Raphson method (sN-R),Crisfield's single parameter method (C1), Crisfield's two parameter method (C2) and Crisfield'sthree parameter method (C3). The new techniques do not involve additional residual force calculationand require little extra computational effort. In addition, they are more robust and efficient thanother existing acceleration techniques.
基金supported by the National Natural Science Foundation of China(Grant No.12393782).
文摘In this paper,the mutual influence of plastic behaviors between kinked macro-crack and kinked micro-crack is analyzed based on the distributed dislocation technique and the dislocation-free zone model.A novel theoretical model for the size of the plastic zone is proposed,where the length of the dislocation array calculated in a specific direction is utilized to characterize the size of the plastic zone at the crack tip.The results demonstrate that,compared with the length of the dislocation array distributed along the crack direction,the length of the dislocation array distributed at a certain specific angle can more accurately characterize the plastic zone at the crack tip.When compared with the results of finite element analysis,the relative error is within 0.2%.Within the theoretical framework of this paper,it is considered that when the dislocation array is set at the crack tip and forms an angle of approximately 25°with respect to the horizontal direction,the calculated length of the dislocation array can effectively characterize the size of the plastic zone.The dislocation density increases with the decrease of the kinking angle of the crack.These results are conducive to predicting the plastic and fracture behaviors of materials containing kinked cracks.
