Defects have a significant impact on the performance of semiconductor devices.Using the first-principles combined with one-dimensional static coupling theory approach,we have calculated the variation of carrier captur...Defects have a significant impact on the performance of semiconductor devices.Using the first-principles combined with one-dimensional static coupling theory approach,we have calculated the variation of carrier capture coefficients with temperature for the interfacial defects P_(b0) and P_(b1) in amorphous-SiO_(2)/Si(100)interface.It is found that the geometrical shapes of P_(b0) and P_(b1) defects undergo large deformations after capturing carriers to form charged defects,especially for the Si atoms containing a dangling bond.The hole capture coefficients of neutral P_(b0) and P_(b1) defects are largest than the other capture coefficients,indicating that these defects have a higher probability of forming positively charged centres.Meanwhile,the calculated results of non-radiative recombination coefficient of these defects show that both P_(b0) and P_(b1) defects are the dominant non-radiative recombination centers in the interface of a-SiO_(2)/Si(100).展开更多
Motivated by inconveniences of present hybrid methods,a gradient-augmented hybrid interface capturing method(GAHM) is presented for incompressible two-phase flow.A front tracking method(FTM) is used as the skeleto...Motivated by inconveniences of present hybrid methods,a gradient-augmented hybrid interface capturing method(GAHM) is presented for incompressible two-phase flow.A front tracking method(FTM) is used as the skeleton of the GAHM for low mass loss and resources.Smooth eulerian level set values are calculated from the FTM interface,and are used for a local interface reconstruction.The reconstruction avoids marker particle redistribution and enables an automatic treatment of interfacial topology change.The cubic Hermit interpolation is employed in all steps of the GAHM to capture subgrid structures within a single spacial cell.The performance of the GAHM is carefully evaluated in a benchmark test.Results show significant improvements of mass loss,clear subgrid structures,highly accurate derivatives(normals and curvatures) and low cost.The GAHM is further coupled with an incompressible multiphase flow solver,Super CE/SE,for more complex and practical applications.The updated solver is evaluated through comparison with an early droplet research.展开更多
Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations wr...Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations written in a quasi conservative form, which is solved by a standard high resolution piecewise parabolic method (PPM) with multi fluid Riemann solver. The level set interface capturing method uses a narrow band ghost fluid method (GFM) with no numerical smearing. Several examples are presented and compared for one and two dimensions, which show the feasibility of the two methods applied to various multi fluid problems.展开更多
In this paper,we present a discontinuity and cusp capturing physicsinformed neural network(PINN)to solve Stokes equations with a piecewiseconstant viscosity and singular force along an interface.We first reformulate t...In this paper,we present a discontinuity and cusp capturing physicsinformed neural network(PINN)to solve Stokes equations with a piecewiseconstant viscosity and singular force along an interface.We first reformulate the governing equations in each fluid domain separately and replace the singular force effect with the traction balance equation between solutions in two sides along the interface.Since the pressure is discontinuous and the velocity has discontinuous derivatives across the interface,we hereby use a network consisting of two fully-connected sub-networks that approximate the pressure and velocity,respectively.The two sub-networks share the same primary coordinate input arguments but with different augmented feature inputs.These two augmented inputs provide the interface information,so we assume that a level set function is given and its zero level set indicates the position of the interface.The pressure sub-network uses an indicator function as an augmented input to capture the function discontinuity,while the velocity sub-network uses a cusp-enforced level set function to capture the derivative discontinuities via the traction balance equation.We perform a series of numerical experiments to solve two-and three-dimensional Stokes interface problems and perform an accuracy comparison with the augmented immersed interface methods in literature.Our results indicate that even a shallow network with a moderate number of neurons and sufficient training data points can achieve prediction accuracy comparable to that of immersed interface methods.展开更多
A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion trajectories.The effective boundary laye...A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion trajectories.The effective boundary layer for inclusion removal was proposed by a statistical method.It is noticed that the capture of inclusions by steel-slag interface is not only dependent on the diameter of inclusions but also related to the local turbulent conditions.In high turbulent flow fields,the transport of inclusions is mainly dominated by the turbulent flow,and thus,the effective boundary layer thickness is mainly affected by the level of turbulent kinetic energy and is almost independent of the inclusion diameter.The inertia of inclusions gradually takes over the stochastic effect of turbulent flow,and the effect of inclusion diameter on effective boundary layer thickness becomes more noticeable with the decrease in the level of turbulent kinetic energy.Besides,the effective boundary layer thickness is more susceptible to the inclusion diameter for larger inclusions due to its greater inertia under the same turbulent condition while it principally depends on the level of turbulent kinetic energy for smaller inclusions.As the characteristic velocity increases,the time for inclusions transport and interaction with steel-slag interface decreases,and thus,the effective boundary layer thickness decreases.Moreover,the graphical user interface was developed by using the cubic spline interpolation for ease of coupling the current boundary layer model with the macro-scale model of a turbulent fluid flow in the metallurgical vessel.展开更多
SMAC method is adopted to solve Navier-Stokes equations, by using fifth-order WENO scheme and TVD R-K scheme, LevelSet methods are used to capture moving interfaces with improved Ghost techniques. Some examples, e.g. ...SMAC method is adopted to solve Navier-Stokes equations, by using fifth-order WENO scheme and TVD R-K scheme, LevelSet methods are used to capture moving interfaces with improved Ghost techniques. Some examples, e.g. the incompressible inviscid flame interfaces of one and two dimensions and the rising-merging of oil bubbles in water, are computed and the comparison with the result of commercial CFD software Fluent has been done. The rationality of LevelSet methods with Ghost technique in capturing moving interfaces with jump conditions is affirmed. It is shown that Level Set method can capture interfaces sharply without complicated reconstruction and can be easily programmed.展开更多
基于网络状碳纳米管(carbon nanotube,CNT)薄膜制备了网络状碳纳米管薄膜场效应晶体管(carbon nanotube thin film field effect transistor,CNT-TFT),研究了温度为100~300 K时,CNT-TFT的电学特性,并对关键电学参数,如开态电流I_(on)、...基于网络状碳纳米管(carbon nanotube,CNT)薄膜制备了网络状碳纳米管薄膜场效应晶体管(carbon nanotube thin film field effect transistor,CNT-TFT),研究了温度为100~300 K时,CNT-TFT的电学特性,并对关键电学参数,如开态电流I_(on)、跨导G_(m)、阈值电压V_(th)和亚阈值摆幅S_(S)等,进行了深入分析。研究结果表明,随着温度的降低,G_(m)出现了下降,V_(th)向左漂移;在G_(m)和V_(th)共同作用下,I_(on)显著下降。通过对电学参数随温度演化机制的深入分析,发现器件G_(m)的降低不仅与CNT内的散射及CNT-金属接触电阻相关,而且与交叠的碳纳米管间的结电阻密切相关。同时,研究还表明,低温下,界面俘获中心对电子俘获概率的减小是引起器件V_(th)和S_(S)变化的主要因素。展开更多
The capture of circulating tumor cells(CTCs)is of great significance in reducing cancer mortality and complications.However,the nonspecific binding of proteins and white blood cells(WBCs)weakens the targeting capabili...The capture of circulating tumor cells(CTCs)is of great significance in reducing cancer mortality and complications.However,the nonspecific binding of proteins and white blood cells(WBCs)weakens the targeting capabilities of the capture surfaces,which critically hampers the efficiency and purity of the captured CTCs.Herein,we propose a liquid-like interface design strategy that consists of liquid-like polymer chains and anti-EpCAM modification processes for high-purity and high-efficiency capture of CTCs.The dynamic flexible feature of the liquid-like chains endows the modified surfaces with excellent antiadhesion property for proteins and blood cells.The liquid-like surfaces can capture the target CTCs and show high cell viability due to the environmentfriendly surface modification processes.When liquid-like surface designs were introduced in the deterministic lateral displacement(DLD)-patterned microfluidic chip,the nonspecific adhesion rate of WBCs was reduced by more than fivefold compared to that in the DLD chip without liquid-like interface design,while maintaining comparable capture efficiency.Overall,this strategy provides a novel perspective on surface design for achieving high purity and efficient capture of CTCs.展开更多
A new technique for accurate determination of the electron and hole capture cross-sections of interface states at the insulator-semiconductor interface has been developed through measuring the initial time variation i...A new technique for accurate determination of the electron and hole capture cross-sections of interface states at the insulator-semiconductor interface has been developed through measuring the initial time variation in the carrier filling capacitance transient, and full consideration is given to the charge-potential feedback effect on carrier capture process. A simplified calculation of the effect is also given. The interface states have been investigated with this technique at the Si-SiO_2 interface in an n-type Si MOS diode. The results show that the electron capture cross-section strongly depends on both temperature and energy.展开更多
基金Project supported by the Science Challenge Project(Grant No.TZ2016003-1-105)Tianjin Natural Science Fundation(Grant No.20JCZDJC00750)the Fundamental Research Funds for the Central Universities,Nankai University(Grant Nos.63211107 and 63201182).
文摘Defects have a significant impact on the performance of semiconductor devices.Using the first-principles combined with one-dimensional static coupling theory approach,we have calculated the variation of carrier capture coefficients with temperature for the interfacial defects P_(b0) and P_(b1) in amorphous-SiO_(2)/Si(100)interface.It is found that the geometrical shapes of P_(b0) and P_(b1) defects undergo large deformations after capturing carriers to form charged defects,especially for the Si atoms containing a dangling bond.The hole capture coefficients of neutral P_(b0) and P_(b1) defects are largest than the other capture coefficients,indicating that these defects have a higher probability of forming positively charged centres.Meanwhile,the calculated results of non-radiative recombination coefficient of these defects show that both P_(b0) and P_(b1) defects are the dominant non-radiative recombination centers in the interface of a-SiO_(2)/Si(100).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10972010,11028206,11371069,11372052,11402029,and 11472060)the Science and Technology Development Foundation of China Academy of Engineering Physics(CAEP),China(Grant No.2014B0201030)the Defense Industrial Technology Development Program of China(Grant No.B1520132012)
文摘Motivated by inconveniences of present hybrid methods,a gradient-augmented hybrid interface capturing method(GAHM) is presented for incompressible two-phase flow.A front tracking method(FTM) is used as the skeleton of the GAHM for low mass loss and resources.Smooth eulerian level set values are calculated from the FTM interface,and are used for a local interface reconstruction.The reconstruction avoids marker particle redistribution and enables an automatic treatment of interfacial topology change.The cubic Hermit interpolation is employed in all steps of the GAHM to capture subgrid structures within a single spacial cell.The performance of the GAHM is carefully evaluated in a benchmark test.Results show significant improvements of mass loss,clear subgrid structures,highly accurate derivatives(normals and curvatures) and low cost.The GAHM is further coupled with an incompressible multiphase flow solver,Super CE/SE,for more complex and practical applications.The updated solver is evaluated through comparison with an early droplet research.
文摘Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations written in a quasi conservative form, which is solved by a standard high resolution piecewise parabolic method (PPM) with multi fluid Riemann solver. The level set interface capturing method uses a narrow band ghost fluid method (GFM) with no numerical smearing. Several examples are presented and compared for one and two dimensions, which show the feasibility of the two methods applied to various multi fluid problems.
基金supports by National Science and Technology Council,Taiwan,under research grants 111-2115-M-390-002 and 110-2115-M-A49-011-MY3,respectively.
文摘In this paper,we present a discontinuity and cusp capturing physicsinformed neural network(PINN)to solve Stokes equations with a piecewiseconstant viscosity and singular force along an interface.We first reformulate the governing equations in each fluid domain separately and replace the singular force effect with the traction balance equation between solutions in two sides along the interface.Since the pressure is discontinuous and the velocity has discontinuous derivatives across the interface,we hereby use a network consisting of two fully-connected sub-networks that approximate the pressure and velocity,respectively.The two sub-networks share the same primary coordinate input arguments but with different augmented feature inputs.These two augmented inputs provide the interface information,so we assume that a level set function is given and its zero level set indicates the position of the interface.The pressure sub-network uses an indicator function as an augmented input to capture the function discontinuity,while the velocity sub-network uses a cusp-enforced level set function to capture the derivative discontinuities via the traction balance equation.We perform a series of numerical experiments to solve two-and three-dimensional Stokes interface problems and perform an accuracy comparison with the augmented immersed interface methods in literature.Our results indicate that even a shallow network with a moderate number of neurons and sufficient training data points can achieve prediction accuracy comparable to that of immersed interface methods.
基金the National Natural Science Foundation of China(Grant Nos.51904025 and U22A20171)the Fundamental Research Funds for the Central Universities(Grant No.FRF-IDRY-20-011)+1 种基金National Postdoctoral Program for Innovative Talents(Grant No.BX20190030)the High Steel Center(HSC)at North China University of Technology and University of Science and Technology Beijing,China.
文摘A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion trajectories.The effective boundary layer for inclusion removal was proposed by a statistical method.It is noticed that the capture of inclusions by steel-slag interface is not only dependent on the diameter of inclusions but also related to the local turbulent conditions.In high turbulent flow fields,the transport of inclusions is mainly dominated by the turbulent flow,and thus,the effective boundary layer thickness is mainly affected by the level of turbulent kinetic energy and is almost independent of the inclusion diameter.The inertia of inclusions gradually takes over the stochastic effect of turbulent flow,and the effect of inclusion diameter on effective boundary layer thickness becomes more noticeable with the decrease in the level of turbulent kinetic energy.Besides,the effective boundary layer thickness is more susceptible to the inclusion diameter for larger inclusions due to its greater inertia under the same turbulent condition while it principally depends on the level of turbulent kinetic energy for smaller inclusions.As the characteristic velocity increases,the time for inclusions transport and interaction with steel-slag interface decreases,and thus,the effective boundary layer thickness decreases.Moreover,the graphical user interface was developed by using the cubic spline interpolation for ease of coupling the current boundary layer model with the macro-scale model of a turbulent fluid flow in the metallurgical vessel.
基金The authors wish to express their gratitude to CAS&973 Project for sponsoring the research,Proj No:KZCX2-YW-302National Natural Science Foundation of China,Proj No:40501017
文摘SMAC method is adopted to solve Navier-Stokes equations, by using fifth-order WENO scheme and TVD R-K scheme, LevelSet methods are used to capture moving interfaces with improved Ghost techniques. Some examples, e.g. the incompressible inviscid flame interfaces of one and two dimensions and the rising-merging of oil bubbles in water, are computed and the comparison with the result of commercial CFD software Fluent has been done. The rationality of LevelSet methods with Ghost technique in capturing moving interfaces with jump conditions is affirmed. It is shown that Level Set method can capture interfaces sharply without complicated reconstruction and can be easily programmed.
文摘基于网络状碳纳米管(carbon nanotube,CNT)薄膜制备了网络状碳纳米管薄膜场效应晶体管(carbon nanotube thin film field effect transistor,CNT-TFT),研究了温度为100~300 K时,CNT-TFT的电学特性,并对关键电学参数,如开态电流I_(on)、跨导G_(m)、阈值电压V_(th)和亚阈值摆幅S_(S)等,进行了深入分析。研究结果表明,随着温度的降低,G_(m)出现了下降,V_(th)向左漂移;在G_(m)和V_(th)共同作用下,I_(on)显著下降。通过对电学参数随温度演化机制的深入分析,发现器件G_(m)的降低不仅与CNT内的散射及CNT-金属接触电阻相关,而且与交叠的碳纳米管间的结电阻密切相关。同时,研究还表明,低温下,界面俘获中心对电子俘获概率的减小是引起器件V_(th)和S_(S)变化的主要因素。
基金supported by the National Natural Science Foundation of China(grant nos.52025132,21975209,22275156,21621091,22021001,22005255,and T2241022)the National Science Foundation of Fujian Province of China(grant no.2022J02059)+4 种基金the Fundamental Research Funds for the Central Universities of China(grant nos.20720220019 and 20720220085)the 111 Project(grant nos.B17027 and B16029)the Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(grant no.RD2022070601)the State Key Laboratory of Bio-Fibers and Eco-Textiles(Qingdao University)(grant no.KFKT202221)the Tencent Foundation(The XPLORER PRIZE).
文摘The capture of circulating tumor cells(CTCs)is of great significance in reducing cancer mortality and complications.However,the nonspecific binding of proteins and white blood cells(WBCs)weakens the targeting capabilities of the capture surfaces,which critically hampers the efficiency and purity of the captured CTCs.Herein,we propose a liquid-like interface design strategy that consists of liquid-like polymer chains and anti-EpCAM modification processes for high-purity and high-efficiency capture of CTCs.The dynamic flexible feature of the liquid-like chains endows the modified surfaces with excellent antiadhesion property for proteins and blood cells.The liquid-like surfaces can capture the target CTCs and show high cell viability due to the environmentfriendly surface modification processes.When liquid-like surface designs were introduced in the deterministic lateral displacement(DLD)-patterned microfluidic chip,the nonspecific adhesion rate of WBCs was reduced by more than fivefold compared to that in the DLD chip without liquid-like interface design,while maintaining comparable capture efficiency.Overall,this strategy provides a novel perspective on surface design for achieving high purity and efficient capture of CTCs.
文摘A new technique for accurate determination of the electron and hole capture cross-sections of interface states at the insulator-semiconductor interface has been developed through measuring the initial time variation in the carrier filling capacitance transient, and full consideration is given to the charge-potential feedback effect on carrier capture process. A simplified calculation of the effect is also given. The interface states have been investigated with this technique at the Si-SiO_2 interface in an n-type Si MOS diode. The results show that the electron capture cross-section strongly depends on both temperature and energy.