为研究分离式Hopkinson压杆（SHPB）试验中不同加载升时试件应力平衡时间对波阻抗比变化的敏感性，将矩形波、梯形波、坡形波等典型的入射加载波形统一表达为具有不同前沿升时的梯形波形式。利用一维应力波理论，分析入射加载弹性应力波在试件中的传播过程，推导出具有任意前沿升时的梯形波入射加载情况下试件内沿加载方向应力分布的相关计算公式。计算得出不同试件-压杆波阻抗比的试件，在不同前沿升时的梯形波入射加载情况下，试件应力平衡时间变化曲线和应力均匀性变化时程曲线，分析入射加载的前沿升时和试件-压杆波阻抗比等有关参数对试件应力平衡时间和应力均匀性的影响规律，得到了一些较为有益的结论，为指导SHPB试验的方案设计和进行有关分析提供理论依据。

Rectangular wave,trapezoidal wave and sloping wave were expressed as trapezoidal wave with different rising times to analyze the sensitivity of time for stress equilibrium to wave impedance ratio in split Hopkinson pressure bar(SHPB) tests. Based on one-dimensional stress wave theory,propagation of incident stress wave in specimen,was analyzed and related calculation formulas for stress distribution along loading direction were obtained under trapezoidal wave with different rising times. Variation curves of time for stress equilibrium and stress uniformity were calculated under trapezoidal wave with different rising times and different specimen-bar wave impedance ratios. Several trapezoidal wave parameters affecting time for stress equilibrium and stress uniformity,such as rising time and specimen-bar wave impedance ratio,were studied;and some useful conclusions were also obtained. Research results can provide a theoretical basis for SHPB experimental designs and related analyses.

基于大涡模拟,结合五阶加权基本无振荡格式以及沉浸边界法对平面入射激波与两种SF_6梯形重气柱的相互作用过程进行了数值模拟,数值结果清晰地显示了激波诱导Richtmyer-Meshkov不稳定性所导致的两种梯形重气柱的变形过程,详细分析了入射激波在两种梯形重气柱界面发生反射、折射、绕射以及折射激波与透射激波在气柱内部来回反射的过程,并研究了该过程中所产生的复杂波系结构,对两种梯形气柱变形过程中与周围空气的混合过程进行了分析;通过记录气柱界面四个特征尺寸随时间的变化对两种梯形气柱界面的不同演化过程进行了定量分析。

Based on the large eddy simulation, combined with the 5th order weighted essentially non-oscillatory scheme and the immersed boundary method, the interaction between planar shock wave and two isosceles trapezoid SF6 cylinders is numerically simulated. Our numerical results clearly show that the deformations of isosceles trapezoid cylinders are induced by the Richtmyer-Meshkov instability due to the interaction of shock wave with them. The reflecting, refracting and diffracting process of incident shock are discussed in detail, and the complex wave structures induced during these processes are revealed. In addition, the mixing mechanism of SF6 gas and air is expatiated. Furthermore, the efforts are made to understand the difference in the evolution of the interface between these two isosceles trapezoid cylinders by analyzing the variation of four characteristic scales.

本文针对一种具有144°平顶梯形波的五相容错永磁无刷直流(BLDC)电机提出了基于转矩等效的容错控制策略。在保证输出转矩相等的基础上,推导了故障条件下的BLDC电机容错式BLAC控制策略。仿真和试验结果表明,该容错控制策略可以保证五相DLDC电机在故障条件下保持正常运行时的转矩性能。

In this paper , a new fault-tolerant control strategy was proposed for remedial operation of a five-phase permanent-magnet brushless DC (BLDC) motor, which had 144°trapsoidal back-EMF.In order to maintain the average torque under normal condition , a remedial brushless AC ( BLAC) mode was proposed for this faulty BLDC motor.Both simulation and experimental results were given , verifying that the new con-trol strategy can enhance the torque performance of faulty operation.

本文介绍了基于LabVIEW的核信号数字滤波器的设计与测试。该数字滤波器实现了3种核信号的数字滤波成形方法---基于小波分析技术的高斯滤波成形、匹配滤波成形和梯形滤波成形。为验证该滤波器的性能，利用计算机产生的数字化核脉冲信号作为信号源，对各种滤波成形算法的效果进行了测试。测试结果表明，该数字滤波器的性能良好，参数调节方便，适用于对核信号进行数字滤波成形。

The design and test of a digital filter to nuclear signals based on LabVIEW were described .Three methods of digital shaping filter to nuclear signals ,which include Gaussian shape filtering based on wavelet analysis technology ,matched shape filtering , and trapezoidal shape filtering were achieved .To verify the performance of the filter ,a digital nuclear signal generator was designed as signal source .The test results of the effect of shaping filter algorithm were studied by altering the filtering parameter .The results show that the digital filter has good performance .

为了探究开尔文源格林函数的快速数值计算方法，从精度与效率两方面对其近场扰动项N和远场波动项W常用的求解算法开展对比分析。 N项的计算方法主要有：制表法、切比雪夫多项式拟合法、有理函数法及改进的梯形法。 W项的计算方法主要有：Bessel函数法和变量代换法。对这些算法的数值分析表明：采用切比雪夫多项式拟合法及制表法计算N项、采用“变量代换法”计算W项的精度与效率较高；两者结合计算Kelvin源格林函数的算法可用于船舶静水航行兴波流场的分析。

This paper discusses numerical methods to evaluate the potential of a near?field disturbance term N and the potential of a Kelvin wavelike disturbance term W, which are two components of the Kelvin source Green''s func?tion. Numerical methods to calculate term N include: table interpolation, Chebyshev polynomials approximations, single integrals of elementary functions and the improved trapezoidal integration rule. And, methods for evaluating term W are:complementary Neumann?series expansions method and variable substitution method. Numerical results prove that:table interpolation and Chebyshev polynomials approximations for term N, variable substitution for term W can provide an effective and accurate solution to the Kelvin source Green’ s function. Thus, the method combing them can be applied to calculate wave?making problem of a ship advancing in calm water.