基于PRONY模型的谐波检测

信号的去噪问题一直是信号检测的一大难题,而要检测的信号往往却存在不同的随机噪声。在分析周期信号的基础上,提出了一种基于PRONY模型的周期信号分析法。经过对周期短(窄)脉冲信号的实验,这种直接构造的PRONY算法在周期信号中能达到有效、准确的分析结果。     

用CR－39固体径迹探测器测定重带电粒子的Bragg峰位

采用ＣＲ－３９固体径迹探测器，根据辐射损伤密度沿粒子的径迹分布规律，测定了经３、４ｃｍ空气降能和φ１ｍｍ孔准直的α粒子（５．１５ＭｅＶ）的Ｂｒａｇｇ峰位。对于通过３ｃｍ空气后能量降至～１２ＭｅＶ的α粒子，在ＣＲ－３９中的Ｂｒａｇｇ峰位大约在７μｍ深度处，理论计算值在６．１４μｍ，实验值与理论值符合得较好。     

Study on characteristics of Ni-W-B composites containing CeO2 nano-particles prepared by pulse electrodeposition

Ni-W-B composites containing CeO2 nano-particles on the surface of 45 steel were prepared by pulse electrodeposition,and the in-fluence of pulse frequency,pulse duty circle and heat treatment temperature on the structures and properties were investigated.The results in-dicated that the pulse co-deposition of Ni,W,B and CeO2 nano-particles led to Ni-W-B/CeO2 composites possessing higher microhardness and better wear resistance when heat-treated at 400 oC for 1 h.The microhardness of 636 HV and the deposition rate of 0.0281 mm/h of the as-deposited alloy were the highest at pulse frequency of 1000 Hz,pulse duty circle of 10% and pulse average current density of 10 A/dm2.The composites were mainly in the amorphous state and were partially crystallized as-deposited,and the crystallization trend was strength-ened when heat-treated at 400 oC.Decreasing pulse duty cycle from 75% to 10% was favorable to the refinement in grain structures and im-provement of microstructures.The crystal sizes of the composites were smaller by means of pulse electrodeposition.     

热释光探测器在脉冲硬X射线能谱测量中的应用

介绍了TLD－3500热释光读出器和GR－100M型热释光剂量片构成的探测器在脉冲硬X射线辐射参数测量中的应用。详细论述了采用滤波荧光法与热释光探测器相结合测量10－10keV的硬X射线能谱的物理思想，在综合考虑了测量环境的具体情况下，设计研制了硬X射线测量系统，建立了热释光探测器对硬X射线绝对能量响应的标定方法。该方法已成功用于脉冲辐射装置“强光1号”的测量，并得到了实测数据。     

基于提升静态小波包变换的自适应消噪方法

基于离散小波变换(DWT)的自适应消噪方法为雷达信号的滤波提供了一种可行的方法.但DWT不具有平移不变性,若不用相同的小波对滤波后的信号进行重构,则会带来较大的重构误差.针对这一现象,提出了一种基于提升静态小波包变换的自适应消噪方法,它推导了静态小波包的提升实现方法,并设计出适合该系统的确定最优小波包分解树的相应步骤,利用引入更多动量因子的权系数迭代公式对各子带进行自适应匹配,并将匹配结果二次自适应,得到拟合的原信号.仿真结果表明,该方法可在计算量增加不大的前提下,进一步改善系统的滤波性能.     

重力注水过程流动不稳定现象关键影响因素研究

重力驱动注水过程中由于流量较小以及蒸汽的积聚可能导致流动不稳定现象的发生,对核反应堆安全运行具有重要的影响。通过实验研究的方法,搭建了重力注水模拟实验装置,研究了不同蒸汽出口形阻、高位储水箱水位和加热棒初始温度下流动不稳定现象的变化规律。结果表明,重力驱动注水过程流动不稳定现象包含冷却水初次注入阶段、注入水逐出阶段和冷却水再注入阶段等。在一定冷却水初始温度、冷却水入口形阻以及系统压力下,蒸汽排出速度以及实验本体内筒顶部的聚集情况取决于蒸汽出口形阻,减小蒸汽出口形阻可加快蒸汽排放速度,压力峰峰值降低、振荡周期变长,有利于系统稳定;提高高位储水箱水位加快了冷却水注入速率,增加了加热棒被淹没率,降低了流动不稳定现象的发生次数和持续时间;随加热棒初始温度的升高,冷却水流量出现了波动向停滞的转变,流动不稳定现象发生的次数增加且持续时间加长。     

Enhancement of optical emission generated from femtosecond double-pulse laser-induced glass plasma at different sample temperatures in air

In double-pulse laser-induced breakdown spectroscopy(DP-LIBS), the collinear femtosecond double-pulse laser configuration is experimentally investigated with different initial sample temperatures using a Ti:sapphire laser. The glass sample is ablated to produce the plasma spectroscopy. During the experiment, the detected spectral lines include two Na(I) lines(589.0 nm and 589.6 nm) and one Ca(I) line at the wavelength of 585.7 nm. The emission lines are measured at room temperature(22 ℃) and three higher initial sample temperatures(T_s?=?100 ℃, 200 ℃, and 250 ℃). The inter-pulse delay time ranges from-250 ps to 250 ps.The inter-pulse delay time and the sample temperature strongly influence the spectral intensity,and the spectral intensity can be significantly enhanced by increasing the sample temperature and selecting the optimized inter-pulse time. For the same inter-pulse time of 0 ps(single-pulse LIBS), the enhancement ratio is approximately 2.5 at T_s?=?200 ℃ compared with that obtained at T_s?=?22 ℃. For the same inter-pulse time of 150 ps, the enhancement ratio can be up to 4 at T_s?=?200 ℃ compared with that obtained at T_s?=?22 ℃. The combined enhancement effects of the different initial sample temperatures and the double-pulse configuration in femtosecond LIBS are much stronger than that of the different initial sample temperatures or the double-pulse configuration only.     

30.4 nm Si/C多层膜反射镜的制备与测量

采用离子束溅射镀膜装置制备了一种新的材料组合Si/C多层膜 ,用于 30 4nm波段的正入射多层膜反射镜。并用软X射线反射率计测得其反射比最大值为 0 14。有效地抑制了 15 0nm处的二级衍射峰。     

矩形波冲击时瓦楞纸板衬垫破损边界曲线的研究

根据瓦楞纸板平压静态模型,建立了动力学方程.通过数值计算方法,研究瓦楞纸板在矩形波激励下的冲击响应,并讨论各参数对瓦楞纸板包装系统的冲击谱和破损边界的影响规律.     

Temperature of the Limiter Surface Measured by IR Camera in HT-7 Tokamak

Temperature measurement by IR （infrared） camera was performed oll HT-T tokamak. particularly during long pulse discharges, during which the temperature of the hot spots on the belt limiter exceeded 1000℃. The heat load on the surface of the movable limiter could be obtained through ANSYS with the temperature measured by IR-camera. This work could be important for the temperature measurement and heat load study on the first wall of EAST device.