Parsivel雨滴谱仪与多普勒天气雷达观测结果对比分析

利用收集到的降水雨滴谱资料与多普勒雷达的观测资料,将Parsivel激光降水粒子谱仪计算的回波强度与雷达观测的回波强度作以比较,结果表明：两者具有较好的一致性,雷达观测到的回波强度有低估的现象,并且降水强度越强,回波强度越大,雷达低估的现象越为明显。经过回波修正后,用统计的Z-I关系式估算的降水量与Parsivel测得的降水量更为接近,可以提高雷达定量估算降水的准确性。     

襄阳新一代天气雷达Z-R关系本地化修正分析

文章利用襄阳市2016年1～12月223个区域站的降水与雷达数据资料,采用最优化Z-R关系,再一次进行降水回波分类,得到适用于不同降水回波类型的Z-R关系,选取几次降水过程中的利用OUP78号产品进行降水估计产品验证,默认Z-R关系比对实际降水有30%以上提升,且层状云降水估计结果优于其它降水回波类型,为新一代天气雷达本地化进一步奠定了基础。     

婺源短时强降水雷达拼图回波分类与特征分析

为了掌握婺源短时强降水的回波分类与特征,文章利用江西WebGIS雷达拼图资料和婺源国家站气象观测数据,采用要素分析、数据统计和图像对比等分析方法,对婺源2015—2020年17次短时强降水的雷达回波特征进行了分析。文章具体介绍了资料来源及短时强降水概况,分析了影响婺源的短时强降水雷达拼图回波系统:絮状回波带、回波短带、单体回波带和雷暴回波带4种类型的特征,同时对婺源的雨量进行了分析。这些分析结果为做好婺源短时强降水天气的预警预报和气象服务奠定了基础。     

X波段双线偏振雷达电磁波衰减订正效果评估

文章以山东省首部X波段全固态双线偏振多普勒天气雷达(724XSP型)的2次强对流天气过程观测资料为例,与济南CINRAD/SA型多普勒天气雷达观测的同一降水系统的回波强度对比,利用差分相移(φDP)订正反射率因子来验证XSP型雷达衰减订正的效果。结果表明:通过对对流云的对比观测,724XSP型天气雷达对45dBz以上强回波的探测能力稍差,当探测到冰雹云时与S波段雷达探测的云体结构差别较大。XSP型雷达经过衰减订正后,与济南SA型雷达的回波强度一致性得到了提高,说明通过差分相移进行电磁波衰减订正是一种有效的订正方法。     

邵阳天气雷达波束遮挡订正方法研究

针对邵阳市天气雷达波束遮挡问题，文章选取了2021—2022年多个降水过程雷达数据，采用平均垂直廓线算法对遮挡区域进行订正，并结合地面雨量数据对比分析订正效果。结果表明：经过订正后，层状云和对流云回波数据连续性均较好，层状云回波的相关性高于对流云回波，雷达回波降水估测能力均有提升，对流云回波较层状云回波降水估测更接近自动气象站实测降水。     

毫米波云雷达数据衰减研究与应用

文章通过分析2021-08-19的1次持续时间长、雨量级小的层状云降水过程，以微雨雷达底层数据作为参考进行系统偏差订正，随后运用逐库法对毫米波云雷达回波进行订正，将订正后的结果与微雨雷达整层回波进行对比，验证订正效果，可为提高天气预报准确度及设计人工影响天气作业方案提供有效的数据支撑。     

“2013.6.27~29”鹰潭市连续性暴雨过程分析

使用常规天气、WebGIS雷达拼图、风廓线雷达和自动气象站等资料,采用物理描述、统计和对比分析等方法,对2013年6月27~29日鹰潭市出现的连续性大暴雨过程,就其对流性降水和持续性降水阶段的环流背景、中尺度系统、雷达回波特征、风廓线雷达特征,以及强降水特征进行分析,结果表明:27~29日的降水分为3个阶段,27日的强对流阶段中,热力、水汽条件均为最高,抬升条件较弱,强降水点分布零散,单点短时降水雨强大;28、29日热力条件近似,短时强降水点较多,区域平均降水量大;宜春风廓线雷达显示,西南急流的加强对鹰潭一带下游降水回波的加强有1~2h的提前预示作用,若同时有低压环流向下游移动,则预示作用更明显;大气低层的切变线和地面辐合线相交处,有利于对流单体生成和发展,良好的热力和水汽条件以及较大的垂直风切变有利于回波强度维持和发展。     

多普勒天气雷达径向干扰回波的识别与消除

多普勒天气雷达在探测气象目标物同时,除了目标物的回波外,一些非目标物的同频电磁波有时也会被散射进入雷达接收系统形成杂波,被称为径向干扰回波。径向干扰回波是污染雷达回波资料的重要因素之一,严重影响雷达资料的定量应用。文章介绍了如何对径向干扰回波进行识别,并给出3种订正方法,即插值法、中值滤波法和多功能插值法,并对这3种方法进行了对比,分析了各种订正方法的优点和局限。实例分析表明通过以上对基数据的处理方法能够对径向干扰回波进行有效的识别和订正,从而获取更准确的雷达基产品及后期导出的二次雷达产品。     

2022-05-29武宁大暴雨天气过程复盘

为了监测预警武宁大暴雨天气，文章利用MICAPS常规天气数据、地面自动气象站气象数据、雷达拼图回波数据等资料，采用天气学原理、雷达气象学原理等技术方法，对2022-05-29武宁一次大暴雨天气过程进行分析，对此次过程中的预报服务进行复盘，结果表明：2022-05-29武宁大暴雨，伴随≥30 mm/h的短时强降水；降水时空分布不均，大暴雨集中分布在武宁县中部一带，强降水主要出现在08:00—14:00,雨量量级与回波强度变化一致；大暴雨主要受高空槽、低层切变线和西南急流共同影响；强降水时段主要受短带回波上反复经过的强单体影响，回波强度为45～55 dBZ;强降水发生前风暴跟踪信息具有密集指向区平行于带状回波的特征，降水持续时间长，有利于发生短时强降水，对临近预报具有很好的指示意义。监测预警、预报服务和实况检验为今后类似天气的预报服务提供宝贵经验。     

风廓线雷达对一次强降水过程的探测研究

文章利用位于北京房山地区的边界层风廓线雷达,对发生在2014-09-01~02的一次强降水过程进行了探测实验研究,结果表明:风廓线雷达可以较好地描述降水期间的水平风场变化,能够清楚地显示出锋前暖区降水、锋面降水过程中低层和高层的典型风场特征;谱参数、回波强度及其谱密度分布在融化区内的变化特征呈现出降水粒子由固态向液态的转化,可以清楚显示出融化层的位置,约2 900~3 900m;谱参数、回波强度及其谱密度分布随时间的变化趋势与降水有较好的对应关系,反映了降水强度的变化;降水期间C2n随时间的变化趋势反映了在该时段内的降水变化,C2n随时间的增大、减小与降水的发生、发展和结束有较好相关性。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.