The determination of time since death or the postmortem interval(PMI)is one of the most important and frequently asked questions in forensic medicine.Medicolegal scholars and forensic pathologists around the world hav...The determination of time since death or the postmortem interval(PMI)is one of the most important and frequently asked questions in forensic medicine.Medicolegal scholars and forensic pathologists around the world have studied the estimation of PMI extensively in the past,and many novel methods and advanced technologies have now been applied in the field.For several centuries,Chinese forensic examiners have also worked on the estimation of the PMI,and there are a large number of excellent studies published in Chinese rather than in English,and these are not easily accessible or known internationally.Therefore we have conducted a review of relevant studies published by Chinese forensic scholars in the last few decades.The scope of this review is to provide a concise summary of the current progress in the estimation of PMI by Chinese forensic researchers using molecular biology,spectroscopic technology,entomological methods,energy changes,thanatochemistry and other methods.展开更多
Uncertainty is extensively involved in the rotor systems of rotating machinery, which may cause an unstable vibrational response. To take the uncertainty into consideration for the uncertain rotor-bearing system, an i...Uncertainty is extensively involved in the rotor systems of rotating machinery, which may cause an unstable vibrational response. To take the uncertainty into consideration for the uncertain rotor-bearing system, an improved unified interval analysis method based on the Chebyshev expansion is established in this paper. Firstly, the Chebyshev Interval Method(CIM) to calculate not only the critical speeds but also the dynamic response of rotor with uncertain parameters is introduced. Then, the numerical investigation is carried out based on the developed double disk rotor model and computation procedure, and the results demonstrate the validity. But when the uncertainty is sufficiently large to influence critical speeds, the upper and lower bounds are far from the actual bounds. In order to overcome the defects, a Bound Correction Interval analysis Method(BCIM) is proposed based on the Chebyshev expansion and the modal superposition. In use of the improved method, the bounds of the interval responses, especially the upper bound,are corrected, and the comparison with other methods demonstrates that the higher accuracy and a wider application range.展开更多
The frequency domain analysis of systems is an important topic in control theory. Powerful graphical tools exist in classic control, such as the Nyquist plot, Bode plots, and Nichols chart. These methods have been wid...The frequency domain analysis of systems is an important topic in control theory. Powerful graphical tools exist in classic control, such as the Nyquist plot, Bode plots, and Nichols chart. These methods have been widely used to evaluate the frequency domain behavior of system. A literature survey shows that various approaches are available for the computation of the frequency response of control systems under different types of parametric dependencies, such as affine, multi-linear, polynomial, etc. However, there is a lack of tools in the literature to construct the Bode envelopes for the general nonlinear type of parametric dependencies. In this paper, we address the problem of computation of the envelope of Bode frequency response of a non-rational transfer function with nonlinear parametric uncertainties varying over a box. We propose two techniques to compute the Bode envelopes：first, based on the natural interval extensions （NIE） combined with uniform subdivision and second, based on the existing Taylor model combined with subdivision strategy. We also propose the algorithms to further speed up both methods through extrapolation techniques.展开更多
目的探讨冲刺间歇训练时两种恢复方式(积极性恢复vs.消极性恢复)对士兵运动能力和训练效果的影响。方法选取18名男性武警士兵完成6组冲刺间歇训练(30 s Wingate全力蹬车试验),间歇期(4 min)分别进行消极性恢复(即在功率自行车上休息)和...目的探讨冲刺间歇训练时两种恢复方式(积极性恢复vs.消极性恢复)对士兵运动能力和训练效果的影响。方法选取18名男性武警士兵完成6组冲刺间歇训练(30 s Wingate全力蹬车试验),间歇期(4 min)分别进行消极性恢复(即在功率自行车上休息)和积极性恢复(以1.1 W/kg负荷继续蹬车),每次Wingate试验时(不包括间歇期)记录峰值功率(PP)、平均功率(MP)、疲劳指数(FI)、总做功(TW)和心率(HR)等参数。结果与消极性恢复比较,积极性恢复PP在第2次Wingate试验时降低(P<0.05),MP和HR在第4~6次Wingate试验时升高,差异均有统计学意义(P<0.05),FI和TW差异无统计学意义(P>0.05)。结论积极性恢复可提高冲刺间歇训练后期的训练效果,士兵应根据训练方案选择合理的恢复方式。展开更多
基金supported by National Sciences Foundation of China(NSFC)[grant numbers 81601645,81671869,81072509,81273339 and 81273335]the Science and Technology Commission of Shanghai Municipality[grant number 14DZ2270800].
文摘The determination of time since death or the postmortem interval(PMI)is one of the most important and frequently asked questions in forensic medicine.Medicolegal scholars and forensic pathologists around the world have studied the estimation of PMI extensively in the past,and many novel methods and advanced technologies have now been applied in the field.For several centuries,Chinese forensic examiners have also worked on the estimation of the PMI,and there are a large number of excellent studies published in Chinese rather than in English,and these are not easily accessible or known internationally.Therefore we have conducted a review of relevant studies published by Chinese forensic scholars in the last few decades.The scope of this review is to provide a concise summary of the current progress in the estimation of PMI by Chinese forensic researchers using molecular biology,spectroscopic technology,entomological methods,energy changes,thanatochemistry and other methods.
文摘Uncertainty is extensively involved in the rotor systems of rotating machinery, which may cause an unstable vibrational response. To take the uncertainty into consideration for the uncertain rotor-bearing system, an improved unified interval analysis method based on the Chebyshev expansion is established in this paper. Firstly, the Chebyshev Interval Method(CIM) to calculate not only the critical speeds but also the dynamic response of rotor with uncertain parameters is introduced. Then, the numerical investigation is carried out based on the developed double disk rotor model and computation procedure, and the results demonstrate the validity. But when the uncertainty is sufficiently large to influence critical speeds, the upper and lower bounds are far from the actual bounds. In order to overcome the defects, a Bound Correction Interval analysis Method(BCIM) is proposed based on the Chebyshev expansion and the modal superposition. In use of the improved method, the bounds of the interval responses, especially the upper bound,are corrected, and the comparison with other methods demonstrates that the higher accuracy and a wider application range.
文摘The frequency domain analysis of systems is an important topic in control theory. Powerful graphical tools exist in classic control, such as the Nyquist plot, Bode plots, and Nichols chart. These methods have been widely used to evaluate the frequency domain behavior of system. A literature survey shows that various approaches are available for the computation of the frequency response of control systems under different types of parametric dependencies, such as affine, multi-linear, polynomial, etc. However, there is a lack of tools in the literature to construct the Bode envelopes for the general nonlinear type of parametric dependencies. In this paper, we address the problem of computation of the envelope of Bode frequency response of a non-rational transfer function with nonlinear parametric uncertainties varying over a box. We propose two techniques to compute the Bode envelopes：first, based on the natural interval extensions （NIE） combined with uniform subdivision and second, based on the existing Taylor model combined with subdivision strategy. We also propose the algorithms to further speed up both methods through extrapolation techniques.
文摘目的探讨冲刺间歇训练时两种恢复方式(积极性恢复vs.消极性恢复)对士兵运动能力和训练效果的影响。方法选取18名男性武警士兵完成6组冲刺间歇训练(30 s Wingate全力蹬车试验),间歇期(4 min)分别进行消极性恢复(即在功率自行车上休息)和积极性恢复(以1.1 W/kg负荷继续蹬车),每次Wingate试验时(不包括间歇期)记录峰值功率(PP)、平均功率(MP)、疲劳指数(FI)、总做功(TW)和心率(HR)等参数。结果与消极性恢复比较,积极性恢复PP在第2次Wingate试验时降低(P<0.05),MP和HR在第4~6次Wingate试验时升高,差异均有统计学意义(P<0.05),FI和TW差异无统计学意义(P>0.05)。结论积极性恢复可提高冲刺间歇训练后期的训练效果,士兵应根据训练方案选择合理的恢复方式。
