利用大型有限元分析软件ANSYS分析了国际热核实验反应堆(ITER)Side校正场线圈(CC)端部三维大圆弧模压成形及释放模具后导体的回弹效应,研究了不同半径成形时导体内外表面的应力、应变的分布及释放模具后导体的回弹规律。设计了1套模压...利用大型有限元分析软件ANSYS分析了国际热核实验反应堆(ITER)Side校正场线圈(CC)端部三维大圆弧模压成形及释放模具后导体的回弹效应,研究了不同半径成形时导体内外表面的应力、应变的分布及释放模具后导体的回弹规律。设计了1套模压成形模具,通过修模的方式在该套成形模具上进行了不同半径成形试验,测得了不同成形半径时模压成形后的回弹量值。试验结果验证了所建立的有限元分析模型的正确性。有限元分析和试验结果表明:ITERSideCC端部三维大圆弧可通过模压成形达到所需的大半径要求,为ITER Side CC端部三维大圆弧成形提供了一种可行方案。展开更多
A hybrid method for synthesizing antenna＇s three dimensional （3D） pattern is proposed to obtain the low sidelobe feature of truncated cone conformal phased arrays. In this method, the elements of truncated cone con...A hybrid method for synthesizing antenna＇s three dimensional （3D） pattern is proposed to obtain the low sidelobe feature of truncated cone conformal phased arrays. In this method, the elements of truncated cone conformal phased arrays are projected to the tangent plane in one generatrix of the truncated cone. Then two dimensional （2D） Chebyshev amplitude distribution optimization is respectively used in two mutual vertical directions of the tangent plane. According to the location of the elements, the excitation current amplitude distribution of each element on the conformal structure is derived reversely, then the excitation current amplitude is further optimized by using the genetic algorithm （GA）. A truncated cone problem with 8x8 elements on it, and a 3D pattern desired side lobe level （SLL） up to 35 dB, is studied. By using the hybrid method, the optimal goal is accomplished with acceptable CPU time, which indicates that this hybrid method for the low sidelobe synthesis is feasible.展开更多
An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem （ECC）, an efficient fractional width-w NAF （FWNA...An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem （ECC）, an efficient fractional width-w NAF （FWNAF） algorithm is proposed to secure ECC scalar multiplication from these attacks. This algorithm adopts the fractional window method and probabilistic SPA scheme to reconfigure the pre-computed table, and it allows designers to make a dynamic configuration on pre-computed table. And then, it is enhanced to resist SPA, DPA, RPA and ZPA attacks by using the random masking method. Compared with the WBRIP and EBRIP methods, our proposals has the lowest total computation cost and reduce the shake phenomenon due to sharp fluctuation on computation performance.展开更多
The automatic platform gates system (APG) and platform screen doors system (PSD) have been applied in the subways in some cities because of its security. As for the two methods,sometimes,it is difficult to decide whic...The automatic platform gates system (APG) and platform screen doors system (PSD) have been applied in the subways in some cities because of its security. As for the two methods,sometimes,it is difficult to decide which one is better for a certain project. The influence of the train-induced air on subway station and the comfort level of subway station in dynamic and transient conditions was analysized based on experimental data. The comfort level,content of inspiratory particles and noise level show that the environment of subway station with APG can satisfy the requirement of the standard. The air conditioning (A/C) cooling load and ventilation energy consumption of the two kinds of subway stations was predicted with the EnergyPlus program. Because electricity consumption by ventilation equipment increases notably when PSD is used,particularly the electricity consumption by the under platform exhaust (UPE) fan,and thus,ultimately,little difference exists in the overall energy consumption with and without PSD. The APG system is economical for the subway stations of the north cities. And it can satisfy the comfort of passengers for whistle stop. It can be concluded that in north cities APG system is better than PSD system.展开更多
Numerical methods for Differential-Algebraic systems with discontinuous right-hand sides is discussed. A class of continuous Rosenbrock methods are constructed, and numerical experiments show that the continuous Rosen...Numerical methods for Differential-Algebraic systems with discontinuous right-hand sides is discussed. A class of continuous Rosenbrock methods are constructed, and numerical experiments show that the continuous Rosenbrock methods are effective. Applying the methods, a fast and high-precision numerical algorithm is given to deal with typical discontinuous parts, which occur frequently in differential-algebraic systems(DAS).展开更多
An adaptive current compensation control for a single-sided linear induction motor(SLIM) with nonlinear disturbance observer was developed. First, to maintain t-axis secondary component flux constant with consideratio...An adaptive current compensation control for a single-sided linear induction motor(SLIM) with nonlinear disturbance observer was developed. First, to maintain t-axis secondary component flux constant with consideration of the specially dynamic eddy-effect(DEE) of the SLIM, a instantaneously tracing compensation of m-axis current component was analyzed. Second,adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer(NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.展开更多
单边短初级长次级直线感应电机己普遍应用于低速磁悬浮的驱动系统。由于在动态纵向边端效应影响下等效电路不对称，单边直线感应电机（single-sided linear inductionmotor，SLIM）的一些参数非线性变化。传统的应用于旋转电机的无速度...单边短初级长次级直线感应电机己普遍应用于低速磁悬浮的驱动系统。由于在动态纵向边端效应影响下等效电路不对称，单边直线感应电机（single-sided linear inductionmotor，SLIM）的一些参数非线性变化。传统的应用于旋转电机的无速度传感器方法不再适用。首先分析了SLIM的M／T轴等效电路，选择次级磁链作为速度观测器状态变量。根据李雅普诺夫系统稳定性判据，推导出适用于SLIM的无速度传感器辨识；然后，采用反馈广义积分观测器控制稳态辨识速度的双幅脉振幅值；引入虚拟期望变量（virtualdesiredvariable，VDV）法，利用估算速度参与SLIM的恒滑差频率矢量控制。仿真与实验对所提控制算法的有效性和实用性进行了验证，所得结论可为磁悬浮的无速度传感器控制提供参考。展开更多
文摘利用大型有限元分析软件ANSYS分析了国际热核实验反应堆(ITER)Side校正场线圈(CC)端部三维大圆弧模压成形及释放模具后导体的回弹效应,研究了不同半径成形时导体内外表面的应力、应变的分布及释放模具后导体的回弹规律。设计了1套模压成形模具,通过修模的方式在该套成形模具上进行了不同半径成形试验,测得了不同成形半径时模压成形后的回弹量值。试验结果验证了所建立的有限元分析模型的正确性。有限元分析和试验结果表明:ITERSideCC端部三维大圆弧可通过模压成形达到所需的大半径要求,为ITER Side CC端部三维大圆弧成形提供了一种可行方案。
基金supported by the Fundamental Research Funds for the Central Universities(YWF-13D2-XX-13)the National High-tech Research and Development Program(863 Program)(2008AA121802)
文摘A hybrid method for synthesizing antenna＇s three dimensional （3D） pattern is proposed to obtain the low sidelobe feature of truncated cone conformal phased arrays. In this method, the elements of truncated cone conformal phased arrays are projected to the tangent plane in one generatrix of the truncated cone. Then two dimensional （2D） Chebyshev amplitude distribution optimization is respectively used in two mutual vertical directions of the tangent plane. According to the location of the elements, the excitation current amplitude distribution of each element on the conformal structure is derived reversely, then the excitation current amplitude is further optimized by using the genetic algorithm （GA）. A truncated cone problem with 8x8 elements on it, and a 3D pattern desired side lobe level （SLL） up to 35 dB, is studied. By using the hybrid method, the optimal goal is accomplished with acceptable CPU time, which indicates that this hybrid method for the low sidelobe synthesis is feasible.
基金supported by the National Natural Science Foundation of China(60373109)Ministry of Science and Technologyof China and the National Commercial Cryptography Application Technology Architecture and Application DemonstrationProject(2008BAA22B02).
文摘An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem （ECC）, an efficient fractional width-w NAF （FWNAF） algorithm is proposed to secure ECC scalar multiplication from these attacks. This algorithm adopts the fractional window method and probabilistic SPA scheme to reconfigure the pre-computed table, and it allows designers to make a dynamic configuration on pre-computed table. And then, it is enhanced to resist SPA, DPA, RPA and ZPA attacks by using the random masking method. Compared with the WBRIP and EBRIP methods, our proposals has the lowest total computation cost and reduce the shake phenomenon due to sharp fluctuation on computation performance.
基金Project(033112911) supported by Tiangjin Science and Technology Committee,China
文摘The automatic platform gates system (APG) and platform screen doors system (PSD) have been applied in the subways in some cities because of its security. As for the two methods,sometimes,it is difficult to decide which one is better for a certain project. The influence of the train-induced air on subway station and the comfort level of subway station in dynamic and transient conditions was analysized based on experimental data. The comfort level,content of inspiratory particles and noise level show that the environment of subway station with APG can satisfy the requirement of the standard. The air conditioning (A/C) cooling load and ventilation energy consumption of the two kinds of subway stations was predicted with the EnergyPlus program. Because electricity consumption by ventilation equipment increases notably when PSD is used,particularly the electricity consumption by the under platform exhaust (UPE) fan,and thus,ultimately,little difference exists in the overall energy consumption with and without PSD. The APG system is economical for the subway stations of the north cities. And it can satisfy the comfort of passengers for whistle stop. It can be concluded that in north cities APG system is better than PSD system.
文摘Numerical methods for Differential-Algebraic systems with discontinuous right-hand sides is discussed. A class of continuous Rosenbrock methods are constructed, and numerical experiments show that the continuous Rosenbrock methods are effective. Applying the methods, a fast and high-precision numerical algorithm is given to deal with typical discontinuous parts, which occur frequently in differential-algebraic systems(DAS).
基金Project(114601034)supported by the Scholarship Award for Excellent Doctoral Students Granted by the Ministry of Education of ChinaProject(61273158)supported by the National Natural Science Foundation of China
文摘An adaptive current compensation control for a single-sided linear induction motor(SLIM) with nonlinear disturbance observer was developed. First, to maintain t-axis secondary component flux constant with consideration of the specially dynamic eddy-effect(DEE) of the SLIM, a instantaneously tracing compensation of m-axis current component was analyzed. Second,adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer(NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.
文摘单边短初级长次级直线感应电机己普遍应用于低速磁悬浮的驱动系统。由于在动态纵向边端效应影响下等效电路不对称，单边直线感应电机（single-sided linear inductionmotor，SLIM）的一些参数非线性变化。传统的应用于旋转电机的无速度传感器方法不再适用。首先分析了SLIM的M／T轴等效电路，选择次级磁链作为速度观测器状态变量。根据李雅普诺夫系统稳定性判据，推导出适用于SLIM的无速度传感器辨识；然后，采用反馈广义积分观测器控制稳态辨识速度的双幅脉振幅值；引入虚拟期望变量（virtualdesiredvariable，VDV）法，利用估算速度参与SLIM的恒滑差频率矢量控制。仿真与实验对所提控制算法的有效性和实用性进行了验证，所得结论可为磁悬浮的无速度传感器控制提供参考。
