轴向盖板型铝电解电容器的可靠性探讨

介绍了一种直卧两用的铝电解电容器,其特征是焊片盖板结构,轴向双向引出,容易散热,能够承受较大的电流冲击,稳定性好,可以提高铝电解电容器产品的可靠性。     

Longstaff利率下巨灾债券定价的一种FFT方法——基于广东省1989~2015台风数据的实证分析

传统的保险市场难以满足日益频发的巨灾风险分散需求,巨灾债券作为一种非传统金融创新工具提供了一种新的分散机制,而精准定价则对巨灾债券的成功发行与交易起着关键作用。本文基于风险中性测度技术,在Longstaff随机利率且巨灾风险累积损失服从复合泊松损失条件下,得到了零息票巨灾债券价格公式;进一步结合广东省1989~2015年台风风暴潮灾害损失数据进行实证分析;最后,针对定价公式复杂性,本文利用快速傅里叶变换方法进行数值求解,结果验证了本文所构模型的可行性。本文的研究是希望能为我国发行巨灾债券与风险测度提供一定的理论基础与技术支持。     

半导体激光器稳功率脉冲电源设计

根据半导体激光器的温度-驱动电流-光功率特性,通过脉冲驱动技术、功率控制技术和抗浪涌技术的综合应用,设计、制作了一种实用的半导体激光器脉冲驱动电源,解决了半导体激光器应用中常见的浪涌冲击问题和宽温度范围内脉冲驱动时的发光功率同步控制难题.     

机载电子设备直流电源输入端保护电路设计

为了减小瞬态电压、浪涌电压、输入电源极性反接、负载短路对机载电子设备造成的危害,针对当前航空直流+28 V电源系统的特点,提出了一种解决直流电源输入过压浪涌、输入欠压浪涌、输入电源极性反接、负载短路或过流导致设备损坏的方案。该方案以LTC4364和APL502 L为核心芯片。首先介绍了该电路的主要特点,接着分析了电路的工作原理和参数设计,最后对该电路进行了仿真分析和实验电路测试。实验结果表明,该电路各项性能指标良好,完全达到设计要求。该电路已成功应用于某电台中,且工作良好。     

Grid convergence studies for the prediction of hurricane storm surge

The focus of this paper is a systematic determination of the relationship between grid resolution and errors associated with computations of hurricane storm surge. A grid structure is sought that provides the spatial resolution necessary to capture pertinent storm surge physics and does not overdiscretize. A set of numerical experiments simulating storm surge generation over 14 grid discretizations of idealized domains examines the influence of grid spacing, shoreline detail, coastline resolution and characteristics of the meteorological forcing on storm surge computations. Errors associated with a given grid are estimated using a Richardson-based error estimator. Analysis of the magnitude and location of estimated errors indicates that underresolution on the continental shelf leads to significant overprediction of the primary storm surge. In deeper waters, underresolution causes smearing or damping of the inverted barometer forcing function, which in turn results in underprediction of the surge elevation. In order to maintain a specified error level throughout the duration of the storm, the highest grid resolution is required on the continental shelf and particularly in nearshore areas. The disparity of discretization requirements between deep waters and coastal regions is best met using a graded grid. Application of the graded gridding strategy to the hindcast of Hurricane Camille reinforces the necessity of using a grid that has high levels of resolution in nearshore regions and areas of complex coastal geometry. © 1998 John Wiley & Sons, Ltd.     

EMC试验中浪涌波形校验方法研究

分析了GB/T17626.5-2008/IEC61000-4-5:2005浪涌信号发生器的参数和波形,搭建了浪涌信号发生器输出端和耦合/去耦网络EUT端口的校验系统。通过在不同校验测试布置下的比对试验,研究分析了可能影响结果的因素,并提出了接地隔离和采用U形短路线等提高校验结果准确性的解决方案。     

IEC浪涌测试标准新发展

浪涌测试是衡量产品电磁兼容性能的重要实验项目,该文通过对新版IEC61000—4—577B／674MCD2012文稿的分析,总结了IEC浪涌标准在波形的定义、耦合去耦网络、测试方法、不确定度估算等方面的新情况。     

开关电源端口浪涌抗扰度抑制措施

针对某开关电源浪涌（冲击）抗扰度试验的失败案例,结合安规要求进行分析,提出了保护电源端口的整改方案,并详细介绍了如何正确选择压敏电阻（MOV）及负温度系数（NTC）热敏电阻。整改后,该产品的浪涌抗扰度测试结果符合标准要求。     

Digital signal propagation delay in a nano-circuit containing reactive and resistive elements

The transient switching delay in a micro/nano-scale circuit containing resistive and reactive elements are sternly affected by the surge in the resistance arising from sub-linear current-voltage (I-V) characteristics limited by the velocity and current saturation. The saturation arises due to the realignment of randomly oriented velocity vectors to the unidirectional streamlined ones in a high electric field when voltage applied across a resistor exceeds its decreasing critical value with reduced channel length. The frequency response f = 1/2πτ_t is affected by a transit time delay τ_t is lower than that predicted from the application of Ohm’s law. The resistance surge dramatically boosts the RC time constant and switching delay and attenuates the L/R time constant and switching delay.