The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase ...The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.展开更多
利用反向Taylor杆撞击实验和数值模拟方法研究了30CrMnSiNi2A钢在高应变率冲击下的动态特性。首先,在Taylor杆冲击实验的基础上,采用Johnson-Cook本构模型和失效模型,对30CrMnSiNi2A钢的反向Taylor杆撞击进行了数值模拟,并将数值模拟结...利用反向Taylor杆撞击实验和数值模拟方法研究了30CrMnSiNi2A钢在高应变率冲击下的动态特性。首先,在Taylor杆冲击实验的基础上,采用Johnson-Cook本构模型和失效模型,对30CrMnSiNi2A钢的反向Taylor杆撞击进行了数值模拟,并将数值模拟结果与实验得到的杆件自由面速度曲线进行对比验证,两者吻合良好。然后,研究了不同长径比的30CrMnSiNi2A钢杆件对反向Taylor杆撞击实验中任意反射面激光干涉测速技术(velocity interferometer system for any reflector,VISAR)测试结果的影响,得到了适用于VISAR测试的Taylor杆长径比范围。最后,运用应力三轴度及损伤度分析了Taylor杆的断裂破坏机理和变形模式,得到了镦粗、蘑菇状变形、花瓣状开裂3种变形模式,并分析了杆件断裂破坏的原因。结果表明:Taylor杆撞击端中心破坏是由于材料受压引起,而撞击端边缘开裂是由于材料处于拉伸状态造成的,且断裂先从边缘开始。展开更多
针对现有大型语言模型在经过剪枝算法处理后在Zero-shot Performance中PPL(困惑度)高、文本生成精度低、模型推理速度慢等问题,提出了一种基于损失联合量级为核心的剪枝度量算法(Loss And Magnitude,LAM)。在对权重重要性估计过程中,将...针对现有大型语言模型在经过剪枝算法处理后在Zero-shot Performance中PPL(困惑度)高、文本生成精度低、模型推理速度慢等问题,提出了一种基于损失联合量级为核心的剪枝度量算法(Loss And Magnitude,LAM)。在对权重重要性估计过程中,将损失函数信息、权重激活信息进行信息融合,使用LAM算法消除在权重重要性评估过程中对梯度信息进行Taylor展开时为提高计算效率省略二阶导数所造成的局限性,提高模型剪枝过程的准确率和鲁棒性,增强剪枝算法的泛用性。在建立耦合结构时,提出单向耦合结构,选择激活Transformer块中的多层感知机(MLP)中的神经元作为初始触发器,只需考虑向注意力层,查询向量、键向量、值向量层方向激活神经元建立耦合结构,从而降低了识别耦合结构组所需的参数量,提高剪枝速度和吞吐量。在WikiText2数据集和PTB数据集进行的Zero-shot Performance实验表明:在剪枝率为25%时对LLaMA-7B进行剪枝处理,其PPL分数分别为20.24和36.05,显著低于其他剪枝算法,在对Vicuna-7B剪枝后的PPL分数为21.24与85.81,也优于其他剪枝算法,表现出更高的泛用性和准确性。展开更多
建立一维格子Boltzmann模型的演化方程,运用Taylor展开和Chapman-Enskog多尺度分析技术,推导出能够恢复一类非线性耦合的NLS-KDV方程的平衡态分布函数和修正函数。最后,数值算例验证出该方法的计算结果与给出的精确解有很好的一致性。Th...建立一维格子Boltzmann模型的演化方程,运用Taylor展开和Chapman-Enskog多尺度分析技术,推导出能够恢复一类非线性耦合的NLS-KDV方程的平衡态分布函数和修正函数。最后,数值算例验证出该方法的计算结果与给出的精确解有很好的一致性。The evolution equations of the one-dimensional lattice Boltzmann model are established, and the equilibrium distribution function and the correction function that can recover a class of nonlinearly coupled NLS-KDV equations are derived by using Taylor expansion and Chapman-Enskog multiscale analysis techniques. Finally, numerical examples verify that the computational results of the method are in good agreement with the given exact solutions.展开更多
Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter IL...Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter ILET restricts its use in space missions.To optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)emission.The CILET can self-organize multiple Taylor cones simultaneously.The cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental system.The emission can be divided into two stable states and one unstable state based on the flow and current characteristics.The current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the voltage.The number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage conditions.The variation law of the number of cones can be explained with the self-organization theory.The variation in the current exhibits a good correlation with the number of cones.This study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.展开更多
A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source di...A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source disturbances are addressed according to their specific characteristics as follows:(A)an MTN data-driven model,which is used for uncertainty description,is designed accompanied with the mechanism model to represent the unmanned systems;(B)an adaptive MTN filter is used to remove the influence of the internal disturbance;(C)an MTN disturbance observer is constructed to estimate and compensate for the influence of the external disturbance;(D)the Extended Kalman Filter(EKF)algorithm is utilized as the learning mechanism for MTNs.Second,to address the time-delay effect,a recursiveτstep-ahead MTN predictive model is designed utilizing recursive technology,aiming to mitigate the impact of time-delay,and the EKF algorithm is employed as its learning mechanism.Then,the MTN predictive control law is designed based on the quadratic performance index.By implementing the proposed composite controller to unmanned systems,simultaneous feedforward compensation and feedback suppression to the multi-source disturbances are conducted.Finally,the convergence of the MTN and the stability of the closed-loop system are established utilizing the Lyapunov theorem.Two exemplary applications of unmanned systems involving unmanned vehicle and rigid spacecraft are presented to validate the effectiveness of the proposed approach.展开更多
Taylor Swift是美国著名创作歌手,擅长在歌词中运用隐喻,尤其在表达爱情主题时。爱情隐喻是认知语言学的重要研究课题。文章在认知语言学视域下以文本细读的方法考察Taylor Swift 11张录音室专辑(共194首歌曲)中的爱情隐喻,发现它们的...Taylor Swift是美国著名创作歌手,擅长在歌词中运用隐喻,尤其在表达爱情主题时。爱情隐喻是认知语言学的重要研究课题。文章在认知语言学视域下以文本细读的方法考察Taylor Swift 11张录音室专辑(共194首歌曲)中的爱情隐喻,发现它们的数量、频率逐年递增、源域类型不断拓展,反映了Taylor对爱情理解的不断深入和多元化。文章重点分析了“爱是战争/斗”“爱是旅程”“爱/恨是火”以及“爱是幽灵”等高频出现的爱情隐喻,相关研究发现可为英语学习者提供参考,也为我国的歌曲创作者提供了借鉴。展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12074399,12204500,and 12004403)the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(No.2021YFE0116700)+1 种基金the Shanghai Natural Science Foundation(No.20ZR1464400)the Shanghai Sailing Program(No.22YF1455300).
文摘The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.
文摘利用反向Taylor杆撞击实验和数值模拟方法研究了30CrMnSiNi2A钢在高应变率冲击下的动态特性。首先,在Taylor杆冲击实验的基础上,采用Johnson-Cook本构模型和失效模型,对30CrMnSiNi2A钢的反向Taylor杆撞击进行了数值模拟,并将数值模拟结果与实验得到的杆件自由面速度曲线进行对比验证,两者吻合良好。然后,研究了不同长径比的30CrMnSiNi2A钢杆件对反向Taylor杆撞击实验中任意反射面激光干涉测速技术(velocity interferometer system for any reflector,VISAR)测试结果的影响,得到了适用于VISAR测试的Taylor杆长径比范围。最后,运用应力三轴度及损伤度分析了Taylor杆的断裂破坏机理和变形模式,得到了镦粗、蘑菇状变形、花瓣状开裂3种变形模式,并分析了杆件断裂破坏的原因。结果表明:Taylor杆撞击端中心破坏是由于材料受压引起,而撞击端边缘开裂是由于材料处于拉伸状态造成的,且断裂先从边缘开始。
文摘针对现有大型语言模型在经过剪枝算法处理后在Zero-shot Performance中PPL(困惑度)高、文本生成精度低、模型推理速度慢等问题,提出了一种基于损失联合量级为核心的剪枝度量算法(Loss And Magnitude,LAM)。在对权重重要性估计过程中,将损失函数信息、权重激活信息进行信息融合,使用LAM算法消除在权重重要性评估过程中对梯度信息进行Taylor展开时为提高计算效率省略二阶导数所造成的局限性,提高模型剪枝过程的准确率和鲁棒性,增强剪枝算法的泛用性。在建立耦合结构时,提出单向耦合结构,选择激活Transformer块中的多层感知机(MLP)中的神经元作为初始触发器,只需考虑向注意力层,查询向量、键向量、值向量层方向激活神经元建立耦合结构,从而降低了识别耦合结构组所需的参数量,提高剪枝速度和吞吐量。在WikiText2数据集和PTB数据集进行的Zero-shot Performance实验表明:在剪枝率为25%时对LLaMA-7B进行剪枝处理,其PPL分数分别为20.24和36.05,显著低于其他剪枝算法,在对Vicuna-7B剪枝后的PPL分数为21.24与85.81,也优于其他剪枝算法,表现出更高的泛用性和准确性。
文摘建立一维格子Boltzmann模型的演化方程,运用Taylor展开和Chapman-Enskog多尺度分析技术,推导出能够恢复一类非线性耦合的NLS-KDV方程的平衡态分布函数和修正函数。最后,数值算例验证出该方法的计算结果与给出的精确解有很好的一致性。The evolution equations of the one-dimensional lattice Boltzmann model are established, and the equilibrium distribution function and the correction function that can recover a class of nonlinearly coupled NLS-KDV equations are derived by using Taylor expansion and Chapman-Enskog multiscale analysis techniques. Finally, numerical examples verify that the computational results of the method are in good agreement with the given exact solutions.
基金co-supported by the National Key R&D Program of China(No.2020YFC2201001)the Shenzhen Science and Technology Program,China(No.20210623091808026)。
文摘Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter ILET restricts its use in space missions.To optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)emission.The CILET can self-organize multiple Taylor cones simultaneously.The cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental system.The emission can be divided into two stable states and one unstable state based on the flow and current characteristics.The current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the voltage.The number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage conditions.The variation law of the number of cones can be explained with the self-organization theory.The variation in the current exhibits a good correlation with the number of cones.This study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.
基金co-supported by the National Key R&D Program of China(No.2023YFB4704400)the Zhejiang Provincial Natural Science Foundation of China(No.LQ24F030012)the National Natural Science Foundation of China General Project(No.62373033)。
文摘A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source disturbances are addressed according to their specific characteristics as follows:(A)an MTN data-driven model,which is used for uncertainty description,is designed accompanied with the mechanism model to represent the unmanned systems;(B)an adaptive MTN filter is used to remove the influence of the internal disturbance;(C)an MTN disturbance observer is constructed to estimate and compensate for the influence of the external disturbance;(D)the Extended Kalman Filter(EKF)algorithm is utilized as the learning mechanism for MTNs.Second,to address the time-delay effect,a recursiveτstep-ahead MTN predictive model is designed utilizing recursive technology,aiming to mitigate the impact of time-delay,and the EKF algorithm is employed as its learning mechanism.Then,the MTN predictive control law is designed based on the quadratic performance index.By implementing the proposed composite controller to unmanned systems,simultaneous feedforward compensation and feedback suppression to the multi-source disturbances are conducted.Finally,the convergence of the MTN and the stability of the closed-loop system are established utilizing the Lyapunov theorem.Two exemplary applications of unmanned systems involving unmanned vehicle and rigid spacecraft are presented to validate the effectiveness of the proposed approach.
文摘Taylor Swift是美国著名创作歌手,擅长在歌词中运用隐喻,尤其在表达爱情主题时。爱情隐喻是认知语言学的重要研究课题。文章在认知语言学视域下以文本细读的方法考察Taylor Swift 11张录音室专辑(共194首歌曲)中的爱情隐喻,发现它们的数量、频率逐年递增、源域类型不断拓展,反映了Taylor对爱情理解的不断深入和多元化。文章重点分析了“爱是战争/斗”“爱是旅程”“爱/恨是火”以及“爱是幽灵”等高频出现的爱情隐喻,相关研究发现可为英语学习者提供参考,也为我国的歌曲创作者提供了借鉴。
