一种具有脉冲宽度甄别的多道分析器

多道分析器剔除脉冲信号中干扰峰的方法一般是采取滤波电路,这不仅增加成本而且增加了电路设计的复杂性。论文提出了一种基于混合信号单片机的具有脉冲宽度甄别功能的多道分析器,利用脉冲宽度甄别技术可以直接剔除脉冲信号中的干扰峰,实现了滤波处理。通过软件与硬件设计实现了具有脉冲宽度甄别的多道分析器,并通过实验结果的比对说明脉冲宽度甄别在脉冲信号处理方面具有的实用意义。     

基于共振的激光脉冲飞行时间测距时刻探测技术

提出了一种基于共振的激光脉冲飞行时间测距时刻探测技术.通过理论分析了单极性准高斯脉冲通过RLC振荡电路后成形的双极性脉冲特性,结果表明,成型后的双极性脉冲信号的过零点与输入信号的幅值无关,因而消除了信号幅度变化对定时精度的影响.介绍了脉冲激光飞行时间探测电路设计,测量了双极性脉冲波形和经过时刻甄别电路后的输出波形,其单次时间测量精度优于67 ps,能够满足高精度脉冲激光测距的要求.     

高功率脉冲微波细胞生物效应中脉冲个数与效应的关系研究

研究了不同脉冲个数的2.71 GHz和9.33 GHz脉冲微波作用于IAR20鼠肝细胞和L-02人肝细胞所导致细胞增殖变化的生物效应,并对实验结果进行分析,通过拟合得到了脉冲个数与脉冲微波非热生物效应之间的剂量效应关系。在本实验范围内,脉冲微波辐照细胞后,细胞增殖率随脉冲个数的增加而呈近似e指数衰减规律,并且在脉冲个数达到一定值时,趋向饱和。     

脉冲强磁体中应力的有限元分析

提高脉冲磁场强度的主要障碍是磁体中巨大的应力,而脉冲磁体中应力的产生和作用过程比较复杂,要准确地计算出来很困难。采用有限元法对脉冲磁体中的应力进行分析,计算中全面考虑了预应力、电磁力、热应力等情况。通过计算,得出了,一些设计脉冲磁体的基本原则。     

双脉冲法精确测量PMT脉冲线性电流的实验设计

PMT脉冲线性电流是PMT在脉冲工作方式下的重要参数,它直接关系到实验结果的可靠性。本文对比各种测量PMT脉冲线性电流方法的优缺点,从提高测量精度方面考虑,设计了基于双脉冲法的测量PMT脉冲线性电流的实验,通过挑选稳定性高的LED作为光源,利用DG2020信号发生器给LED灯供电,采用通道循环功能加长信号时间间隔,使用分路输出到两台示波器接收信号,应用示波器多次采集自动取平均的功能等方法在实验细节上进行设计,提高测量精度。通过实验测到了PMT脉冲输出电流偏离线性直线1%处的电流,并获得了PMT脉冲输出的mA级至A级电流全曲线。     

统一混沌系统的脉冲控制与同步

对统一混沌系统的脉冲控制稳定性与同步问题进行了理论分析，利用脉冲微分方程理论给出了脉冲控制稳定与同步的充分条件，并对脉冲控制时间间隔的范围作了估计。最后，通过仿真进行了验证。     

脉冲慢正电子束流的检测

本工作设计了一种通过测量脉冲慢正电子湮没辐射在闪烁探测器的积分效应进行测量和标定脉冲正电子束流强度的方法.通过对探测器的刻度,定量测量了北京慢正电子强束流项目中慢正电子束流的流强和能谱发布,为脉冲正电子束流的直流化设计提供了依据.     

空气脉冲混合澄清槽放大设计的研究

本文通过对空气脉冲混合澄清槽的实验研究,提出了purex过程空气脉冲混合澄清槽混合室的放大设计准则是(P/V)b~(0.52)=0.73,澄清室可按比澄清速度不变放大设计,最大比澄清速度为3.5ml/cm~2·min;说明了脉冲操作条件的选取应首先根据混合液深度确定脉冲振幅,再由脉冲输入能量、脉冲管径等参数确定脉冲频率;另外还推荐了空气脉冲混合澄清槽可采用较两管脉冲搅拌更为优越的四管脉冲搅拌。空气脉冲混合澄清槽采用多管脉冲搅拌,输入能量可进一步增大,这为空气脉冲混合澄清槽的放大应用提供了新的途径。     

α、β粒子在钝化注入平面硅探测器中的脉冲形状分析

利用钝化注入平面硅探测器(PIPS)测量α、β时,某些情况下只通过能量甄别无法区分这两种粒子,而通过脉冲形状甄别的方法可以很好地解决这一问题.通过研究α、β粒子在PIPS中脉冲形状不同的机制,分析了脉冲形状的特征；测量分析了一款PIPS探测器的电压脉冲上升时间及其随偏压的变化；分析得出了对PIPS探测器进行脉冲形状甄别...     

MHz重复频率双脉冲高压实验研究

介绍了在小型电子直线感应加速器（Mini-LIA）平台上利用两套相同的单脉冲高压功率系统通过脉冲汇流装置获得MHz重复频率双脉冲高压的实验结果。实验结果表明双脉冲高压间隔百纳秒至微秒可调,验证了通过汇流装置可获得百纳秒间隔多脉冲高压。     

软X射线喷射冲量的解析计算

基于X射线能量沉积的分配原则,给出了一种脉冲软X射线喷射冲量的解析计算方法,并在“强光一号”加速器上实验测量了软X射线辐照产生的喷射冲量。该解析计算方法的计算结果与BBAY公式计算结果一致,也与实验结果符合较好。本解析计算方法可应用于工程上对X射线喷射冲量的估算。     

Life test research of a high specific impulse Hall thruster HEP-140MF

In this study, a high specific impulse Hall thruster, HEP-140MF, having a high discharge voltage, was used to accelerate ions. We aimed to obtain a high specific impulse and an acceleration zone moving downstream toward the channel exit to reduce wall sputtering erosion of the walls of the discharge channel, hence ensuring an enhanced lifetime. To study the lifetime characteristics of the high specific impulse Hall thruster, a life test was performed on the HEP- 140MF thruster for the first time, and performance parameters, such as thrust, specific impulse, and efficiency, were measured. Changes in the performance parameters and evolutions in the surface profiles of the discharge channel wall were summarized. The reasons contributing to these changes during the life test were analyzed. Moreover, the accelerated life test method was validated on the HEP-140MF.     

Micro-impulse and plasma plume produced by irradiating aluminum target with nanosecond laser pulses in double-pulse scheme

The micro-impulse generated by ablating an aluminum target in double-pulse laser bursts with different interpulse delays was investigated using a torsion pendulum. The plasma plume was simultaneously visualized using high-speed photography to analyze the coupling mechanism of the ablation impulse. The experiment was carried out using a pulsed laser with a pulse width of 8 ns and a wavelength of 1064 nm. The experimental results show that an impulse with an interpulse delay of 60 ns is roughly 60% higher than that with no delay between the two pulses, when the energy of both laser pulses is 50 mJ. Therefore, double-pulse schemes could enhance the ablation impulse under certain conditions. This is because the ablation of the first laser pulse changes the optical properties of the aluminum target surface, increasing the absorptivity. However, the ablation impulse is reduced with a time delay of 20 ns when the energy of both laser pulses is 100 mJ or 150 mJ. It can be concluded that the plasma produced by ablating the aluminum with the first pulse shields the second laser pulse. To summarize, the experimental results show that different delay times in a double-pulse scheme have a significant effect on the ablation impulse. The study provides a reference for the optimization of the parameters when laser ablation propulsion with a double-pulse scheme is applied in the fields of space debris removal, laser ablation thrusters, and so on.     

Insulation characteristics of triple mixtures of c-C4F8/N2/CO2 under lightning impulse voltage

This paper has researched the insulation characteristics of 10%c-C₄F₈/N₂/CO₂ mixtures under lightning impulse voltage by experiment. It is shown that the positive and negative lightning impulse breakdown voltages of 10%c-C₄F₈/N₂/CO₂ gas mixtures rise linearly as the electrode gap distance and gas pressure increase and under the same conditions, the positive lightning impulse breakdown voltage of the gas mixtures is always higher than the negative lightning impulse breakdown voltage. As the gas mixtures have a little higher liquefied temperature than SF₆ and the comprehensive GWP is about 5% of SF₆ , and the positive and negative lightning impulse breakdown voltages can both reach 60% of SF₆ , 10%c-C₄F₈/N₂/CO₂ gas mixtures can be applied as insulation gas in electrical equipment such as C-GIS, GIT, GIL and so on.     

Scaling laws for contained explosions

Assessment of structural integrity under postulated accident conditions in fast reactors has been based, in the past, on results of scale model tests conducted with chemical explosives. Though emphasis has currently shifted to the development and use of elaborate computational models to determine structural response in the postulated accident, idealised scale model experiments still serve the useful purpose of providing by extrapolation estimates of pressure, impulse and deformation without much expense or loss of time. However, the choice of appropriate scaling laws is important in performing the extrapolation. The results of experiments carried out for the case of a charge of high explosives set off in open waterfilled cylindrical vessels are presented and compared with earlier work by others. Measured shock overpressures at the vessel wall are reported as also impulse values derived by determining the area under the pressure-time traces. Deviations from free-field scaling laws have been observed which are significant for wall pressures and less so for impulse received by the vessel wall.     

强流ns同轴分流器及其强度分析

文章叙述了一个金属箔同轴分流器的结构和设计方法,刻度表明,该分流器的上升时间约2ns。从动力学的角度出发,推导出了同轴分流器的一个新的强度公式,它比Park公式更符合于实验结果。     

Behavior of viscoplastic circular plates under Gaussian impulse

The dynamic plastic behavior of viscoplastic circular plates subjected to impulse loading is presented. The impulse is assumed to impart a transverse axisymmetric velocity with a spatial Gaussian distribution. The combined influence of membrane forces, bending moments and strain-rate sensitivity is considered in predicting the deformation. Numerical results are presented to show this influence on the rate of growth of plastic regimes, the deflection configuration and the total time of response. It is concluded that the spatial distribution of impulse has a considerable effect on the deformation response of the plate, and relatively small effect on the total time of response; furthermore, the simple bending theory is inadequate to reliably predict the response.     

A Novel Crowbar Impulse Current Circuit for Testing the Switch-Type SPD

A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main discharging switch, and a crowbar pseudospark switch. The active trigger technology was studied in the crowbar impulse current circuit. The circuit monitors the main discharging current and generates a trigger signal at a proper time for the crowbar pseudospark switch operation. The trigger characteristics of the main discharge switch and the crowbar pseu- dospark switch were investigated. By monitoring the preset applied capacitor voltage, the gap distance of the main discharging switch could be adjusted to ensure a discharging delay time less than 2 μs. Equipped with a surface ttashover trigger device made of high relative perimittivity dielectric material BaTiO3 （εr = 3460）, the discharge delay time of the crowbar pseudospark switch is less than 85 ns, and the minimum operating voltage is less than 1% of its self-breakdown voltage. With a storage capacitor of 9 μF , an inductor of 18 μH and a crowbar pseudospark switch, a load of 30 mΩ and an applied capacitor voltage of 40 kV, an impulse current waveform of maximum 25 kA was generated with a rise time and time to half peak value of 17.2 μs and 336μs respectively.     

Effect of Implantation Machine Parameters on N^＋ ion Implantation for Upland Cotton（Gossypium hirsutum L.）Pollen

Effect of parameters of ion implantation machine, including ion energy, total dose, dose rate, impulse energy and implantation interval on the pollen grains of upland cotton implanted with nitrogen ion beam were studied. The best parameters were screened out. The results also showed that the vacuum condition before the nitrogen ion implantation does not affect the pollen viability.     

Application of wavelet transform de-noising in pole identification of a system

Due to the multiscale character of wavelet transform, the method of wavelet transform de-noising (WTDN) is introduced. The WTDN method neither requires extra limit of frequency range for the processed signal,nor needs a prior estimate of impulse response for an identified system, so it is especially suitable to de-noise the wide-band signal and the impulse response of a blind system. The numerical simulation results indicate that the WTDN method is reliable, The WTDN method was used to process the sampled data from a preamplifier coupled to a gas detector. The experimental results also show that the WTDN method can effectively improve the SNR of sampled data and enhance the accuracy in pole identification of the system,