基于PMT模块的供电电路及信号调理电路的设计与实现

本文介绍的是基于光电倍增管(PMT)模块的供电电路及信号调理电路的设计,用于浮游植物粒径检测系统中微弱荧光信号的检测。设计的供电电路将开关电源输出的12V电压转换为低噪声、低纹波、稳定性好的±5V的电压供光电倍增管模块及其信号调理电路使用,实现了一个电源多种应用的目的,并为PMT模块的输出信号设计了信号调理电路,减小了光电检测电路的噪声,提高了检测精度。     

光电倍增管工作特性简述

在光谱分析等领域中,光电倍增管的工作特性至关重要。因为目前使用的管子型号繁多(单美国就生产约550个),而引起这些管子工作特性改变的因素又多种多样,所以在工作中我们应对光电倍增管的工作特性予以高度重视。本文试对常见的光电倍增管工作特性作一简要叙述,供大家参考。一、光谱特性光电倍增管的光谱特性主要由阴极材料、窗口材料决定,同时也受温度,磁场和时间的影响,甚至和入射辐射照射的光电阴极的部位也有关。表1给出了部分美国S系列光阴极材料和窗口材料。图1给出了部分S系列光阴极的光谱响应曲线,图2给出了部分非S系列的     

气囊对光电倍增管水下内爆影响试验研究

江门中微子试验中使用的光电倍增管需要长时间承受高静水压力作用,由于光电倍增管外壳使用膨化硅玻璃制造,受自身结构微观缺陷影响不可避免的有发生碎裂的可能,并引发光电倍增管的水下内爆(Implosion),对其周围设施造成危害。在可加压密封罐中进行带有气囊的光电倍增管水下内爆试验,使用高速摄像和压力传感器记录实验过程数据。并将试验结果与无气囊条件下的光电倍增管水下内爆相关数据进行对比,探究了使用气囊进行光电倍增管水下内爆防护的可行性,为光电倍增管的水下内爆防护提供新的思路。     

光电倍增管在全息光盘条形码阅读器中的应用

光电倍增管（ｐｈｏｔｏｍｕｌｔｉｐｌｉｅｒｔｕｂｅ）的应用已有几十年的历史，尽管六十年代固体器件的出现，使光电倍增管一度面临激烈的竞争，但光电倍增管仍以其灵敏度高、时间响应度好、增益高及噪声低等一系列优点，依然应用于要求较严格的场合，如微弱信号处理等。本文就是介绍其在一种微弱信号探测（全息光盘条形码阅读器）中的应用。     

核测量用光电倍增管性能测试方法

从测试的目的、原则、内容、方法、以及测试数据的处理方法5个方面,论述了核测量用光电倍增管的性能测试方法,对多种光电倍增管的性能测试结果表明,这些内容完全满足核测井仪器研制与生产的需要,在分析光电倍增管坪特性影响因素的基础上,结合了射线强度测量的具体特点,提出了改进光电倍增管性能和使用效果的一些建议。     

真空紫外微通道板光电倍增管的研制

主要讨论了真空紫外微通道板光电倍增管的工作原理及设计考虑。介绍了这种新型弱光探测器研制过程中的主要关键技术以及该器件所具有的良好性能和广阔的应用前景     

真空紫外微通道板光电倍增管的研制

主要讨论了真空紫外微通道板光电倍增管的工作原理及设计考虑，介绍了这种新型弱光探测器研制过程中的主要关键技术以及该器件所具有良好性能和广阔的应用前景。     

介质阻挡放电光电检测装置研究

采用光电倍增管(PMT)研制一种探测介质阻挡放电(dielectric barrier discharge,DBD)微弱光信号的光电检测装置。根据DBD微弱光信号的特点,进行光电检测装置设计,通过光纤排、光电转换电路、示波器放大并采集微弱光信号。使用新装置进行大气压下DBD的检测试验,验证该新型装置较传统的DBD检测装置具有灵敏度高、响应速度快、可有效区分放电与干扰信号、可同时采集多点信号等特点,为DBD的试验研究提供可靠的探测方法。     

水下中空结构物内爆试验方法研究

通过对直径3 m、长5 m的钢制压力罐内水域上方空气加压,进行0.5 MPa水域环境下的光电倍增管内爆试验。在压力罐内壁粘贴声阻抗较小的橡胶层,能有效减小钢制壁面反射冲击波对内爆试验结果的影响,通过压力罐视窗提供的大功率灯光,为高速摄像机提供光源。在压力罐中进行0.5 MPa水域环境下光电倍增管内爆试验得到了和理论研究一致的冲击波压力时域曲线,拍摄到清晰的光电倍增管内爆过程,该研究内容为水下中空结构物内爆提供了一种较好的试验方法。     

超快速MCP-PMT的时间特性测试方法研究

超快速时间特性的光电倍增管的时间特性研究,对进一步研制国产超快时间响应的微通道板光电倍增管(FPMT)具有重要的指导作用。本文基于高能物理通用的VME测试方案,设计装置采用皮秒激光器的单光子脉冲工作模式,最终实现系统误差为25 ps的FPMT高精度时间测试系统。通过优化FPMT阳极信号读出方式、优化分压器结构及分压比例,对多款FPMT的时间特性进行测试研究。并提出在非单光子工作模式下表征FPMT时间分辨特性的本征时间下限值,用以对比分析各种不同工作状态的FPMT的时间分辨好坏。在对多款FPMT读出方式完成优化结构设计和对比测试后,研究结果表明,目前实验室来自不同生产单位的样管中,最佳的本征时间分辨下限值为30 ps。     

Proposals for producing novel periodic structures by ion bombardment sputtering

It is proposed, and confirmed analytically that if multiple ion fluxes are incident simultaneously, all at the same oblique polar angle but at different azimuthal angles, on to a target then the individual ripple patterns generated by sputtering are superimposed to produce novel surface structures. It is also shown that single focused ion fluxes incident on to rotating targets can produce circular ripple patterns.     

Ripple compensation for torque sensors built into harmonic drives

Harmonic drives include a mechanically flexible component which transmits load torque, and therefore, a torque sensor can be built into harmonic drives by cementing strain gages on a flexible component of the gear. However, a periodic sensing error called ripple is generated by deformation of a flexible component during the gear operation. The ripple signal cannot be sufficiently compensated by pairs of strain gages that produce opposite phase signals, because the strain gages cannot be exactly positioned on the desired locations. In this paper, we present a method to compensate the ripple by a new approach of tuning the ripple amplitudes for separate strain gages. The ripple, caused by positioning errors of the strain gages, can be perfectly compensated, and, therefore, the requirement for accurate strain gage positioning is reduced. The method does not need any online calculations, and consequently, the torque signal is not delayed. The minimum number of strain gages needed to compensate a given number of frequency components of a ripple is derived. Some experimental results are shown     

Does the ripple effect influence the bullwhip effect? An integrated analysis of structural and operational dynamics in the supply chain†

The ripple effect refers to structural dynamics and describes a downstream propagation of the downscaling in demand fulfilment in the supply chain (SC) as a result of a severe disruption. The bullwhip effect refers to operational dynamics and amplifies in the upstream direction as ordering oscillations. Being interested in uncovering if the ripple effect can be a driver of the bullwhip effect, we performed a simulation-based study to investigate the interrelations of the structural and operational dynamics in the SC. The results advance our knowledge about both ripple and bullwhip effects and reveal, for the first time, that the ripple effect can be a bullwhip-effect driver, while the latter can be launched by a severe disruption even in the downstream direction. The findings show that the ripple effect influences the bullwhip effect through backlog accumulation over the disruption time as a consequence of non-coordinated ordering and production planning policies. To cope with this effect, a contingent production-inventory control policy is proposed that provides results in favour of information coordination in SC disruption management to mitigate both ripple and bullwhip effects. The SC managers need to take into account the risk of bullwhip effect during the capacity disruption and recovery periods.     

单相串励电动机转矩波动抑制方法研究

单相串励电动机工作时存在转矩波动,导致了明显的振动和噪声,限制了其应用范围,为此提出了一种基于振动波叠加抵消的单相串励电动机转矩波动抑制方法,即在原有单相串励电动机转矩波动的基础上,叠加另外一个幅值相同、相位错开180°电角度的振动波。通过对单相串励电动机的工作机理的剖析,得到了转矩波动抑制方法的实现条件。最后通过实验对叠加振动波后电动机的转矩波动进行了测试,结果表明其转矩波动可以得到有效的消减,由此验证了所提出的转矩波动抑制方法的可行性。     

Ripple effect modelling of supplier disruption: integrated Markov chain and dynamic Bayesian network approach

The ripple effect can occur when a supplier base disruption cannot be localised and consequently propagates downstream the supply chain (SC), adversely affecting performance. While stress-testing of SC designs and assessment of their vulnerability to disruptions in a single-echelon-single-event setting is desirable and indeed critical for some firms, modelling the ripple effect impact in multi-echelon-correlated-events systems is becoming increasingly important. Notably, ripple effect assessment in multi-stage SCs is particularly challenged by the need to consider both vulnerability and recoverability capabilities at individual firms in the network. We construct a new model based on integration of Discrete-Time Markov Chain (DTMC) and a Dynamic Bayesian Network (DBN) to quantify the ripple effect. We use the DTMC to model the recovery and vulnerability of suppliers. The proposed DTMC model is then equalised with a DBN model in order to simulate the propagation behaviour of supplier disruption in the SC. Finally, we propose a metric that quantifies the ripple effect of supplier disruption on manufacturers in terms of total expected utility and service level. This ripple effect metric is applied to two case studies and analysed. The findings suggest that our model can be of value in uncovering latent high-risk paths in the SC, analysing the performance impact of both a disruption and its propagation, and prioritising contingency and recovery policies.     

The impact of digital technology and Industry 4.0 on the ripple effect and supply chain risk analytics

The impact of digitalisation and Industry 4.0 on the ripple effect and disruption risk control analytics in the supply chain (SC) is studied. The research framework combines the results from two isolated areas, i.e. the impact of digitalisation on SC management (SCM) and the impact of SCM on the ripple effect control. To the best of our knowledge, this is the first study that connects business, information, engineering and analytics perspectives on digitalisation and SC risks. This paper does not pretend to be encyclopedic, but rather analyses recent literature and case-studies seeking to bring the discussion further with the help of a conceptual framework for researching the relationships between digitalisation and SC disruptions risks. In addition, it emerges with an SC risk analytics framework. It analyses perspectives and future transformations that can be expected in transition towards cyber-physical SCs. With these two frameworks, this study contributes to the literature by answering the questions of (1) what relations exist between big data analytics, Industry 4.0, additive manufacturing, advanced trace & tracking systems and SC disruption risks; (2) how digitalisation can contribute to enhancing ripple effect control; and (3) what digital technology-based extensions can trigger the developments towards SC risk analytics.     

A study of the early stages of erosion of 1100 aluminum using a mechanical properties microprobe

The incubation period during erosion of 1100 Al has been studied by monitoring the changes occurring in the immediate subsurface layers using a mechanical properties microprobe. The results show that the very near surface regions reach maximum hardness well before steady state, concurrent with the development of a characteristic surface ripple structure. This is interpreted as support for models of material removal in steady state based on some form of critical strain criteria rather than a fracture flow stress. It is also observed that material under valleys in the ripple structure is hardened to shallower depths. The significance of this result is not yet clear but appears to be linked to the development of the ripple structure.     

Infrared spectroscopy of a silicon surface bombarded by nitrogen ions

Transmission Fourier-transform infrared spectroscopy was used to study the formation of a ripple topology on a silicon surface bombarded by nitrogen ions, together with the formation of silicon nitride, the evolution of its composition and structure. For the first time, an attempt is made to study the evolution of the formation of a ripple topology on the surface of silicon by analyzing the main spectral characteristics (amplitude, position, and profile) of the infrared absorption bands. It is shown that the change in the profile of the characteristic absorption band and the position of its peak correlate with the characteristics of formation of the ripples on the silicon surface. It is demonstrated that infrared transmission spectroscopy can be used to study surface structuring processes for semiconductors bombarded by ions of chemically active elements. Pis’ma Zh. Tekh. Fiz. 24, 18–23 (March 26, 1998)     

Proposals for producing novel periodic structures on silicon by ion bombardment sputtering

It is proposed, and confirmed analytically, that if multiple ion fluxes are incident simultaneously, at different oblique polar angles but at the same Azimuthal angle, on to a target, then the individual ripple patterns generated by sputtering are superimposed to produce novel surface structures. It is also shown that multiple focused ion fluxes incident on to rotating targets can produce circular novel patterns.     

Resonant conversion of plasmons in a rippled metal-insulator structure

The propagation of long-range plasmons on a rippled metal film embedded in an insulator is studied. It is shown that the ripple of the film leads to the appearance of additional dissipative losses of these plasmons. It is established that these additional losses are caused by resonant coupling between long-range and short-range plasmons produced by the ripple of the film. Pis’ma Zh. Tekh. Fiz. 24, 22–29 (September 26, 1998)