Latitudinal features of Total Electron Content over the African and European longitude sector following the St. Patrick’s day storm of 2015

GNSS TEC values have been obtained from 18 stations distributed from the magnetic equator to nearly 80°N magnetic dip in the African and west-European longitude sector corresponding to the March 17–18, 2015 geomagnetic storm. Significantly depleted ionosphere have been observed at stations north of 50°N geographic on March 18, 2015 following the above storm over a longitude swath 11.9°–21°E covering the Eastern Africa and Western European longitude sector. High ROTI values were noted on March 17^th at locations around 80°N magnetic dip. Two prominent peaks in PCN were noted around 09:00 UT and 14:00 UT on March 17, 2015 and around 15:00 UT on March 18, 2015. Daytime thermospheric (O/N₂) ratio was markedly less on March 18th at latitudes above 60°N geographic which is suggested to be the major driver behind depleted high latitude ionosphere during the recovery phase of the storm on March 18, 2015.     

航空发动机脉动式装配生产线工艺仿真关键技术研究

面向国内民用航空发动机总装批产能力建设的需求,对标国内外先进脉动式装配生产线的研发进度和实施状态,在建设规划阶段,提出了脉动式总装生产线的工艺仿真方案。阐述了脉动式总装生产线工艺仿真的主要技术内容和关键技术方向,重点对关键技术的解决方案和实施途径进行规划,包括装配网络图建模及优化、车间工艺布局及生产仿真、基于二三维关联集成仿真的虚拟产品制造,最后对脉动式生产线数字孪生体进行了展望。     

精密“光机—光电”位移传感器的研究与设计

提出了一种在普通扭簧比较仪上增加光学传动元件和新颖光电传感元件的精密“光机光电”位移传感器的设计新思路。这种传感器具有很高的灵敏度和分辨力，有较高的线性度和示值稳定性。     

On Truncation Error Bounds for Sampling Representations of Band-Limited Signals

All sampling representations of band-limited signals involve infinite sums. The truncation error associated with a given representation is defined as the difference between the signal and an approximating sum utilizing a finite number of terms. In this paper truncation error is expressed as a contour integral for Lagrange interpolation, general Hermite interpolation, the Shannon series (cardinal series), the Fogel derivative series, and multidimensional sampling expansions. Truncation error bounds are obtained under various constraints on the signal magnitude, spectral smoothness, and energy content.     

工装用标准限用方法

介绍了南飞公司多年来对工装用标准限用的一些原则和做法。     

水下转台系统的一种实验建模方法

针对非线性摩擦特性对伺服系统建模的影响问题,通过适当的实验设计,利用优化方法来得到系统非线性摩擦模型以及系统模型参数.实验结果表明,利用该方法可以得到与实际系统模型参数较为接近的对象模型参数.     

民用飞机飞行操作程序的开发和验证

飞行操作程序的开发和验证是一项庞大而复杂的长期工作,需要考虑的因素和问题很多。在实际型号程序开发经验和对大量资料研究的基础上,系统地提出了一种民用飞机飞行操作程序开发和评估的基本方法,对相关工作的指导性原则、设计方法、内容要求、关键要素和表现形式等进行了较为详细的说明。该方法主要着眼于程序设计本身,是这方面工程经验和实践的再总结和提炼,并力求对飞行操作程序开发工作起到有效指导作用。     

工程常见塔间距下大型冷却塔的双塔干扰效应

针对工程常见塔间距下冷却塔双塔干扰效应采用风洞试验方法进行研究,通过增加模型表面粗糙度来补偿模型试验的雷诺数效应,变化塔间距和风向角进行125种工况的风洞试验,进行基于有限元的风致响应计算,获得不同风向角和塔间距下的整体风荷载和风致响应,并以此进行双塔的干扰效应研究。研究发现双塔并行放置时,由于"狭缝效应"的存在使得顺风向塔底剪力的干扰系数大于1,此时塔间距越小,干扰效应越显著;本文研究的塔间距下基于多组风荷载和风致响应指标的干扰系数最大值约为1.15;顺风向塔底剪力和弯矩的干扰系数最大值大约出现在67.5°风向,基于风致响应指标的最大值出现在90°≤θ≤150°之间的风向。