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Cutting edge preparation of microdrills by shear thickening polishing for improved hole quality in electronic PCBs

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Frontiers of Mechanical Engineering 2024年第2期19卷 99-107页

作者： Jiahuan wang Mingfeng KE Jiepei LIAO Yu ZHOU Saurav GOEL Jaya VERMA Xu wang Weigang GUO Julong YUAN binghai LYU College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310000China Ultra-precision Machining Center Key Laboratory of Special Purpose Equipment and Advanced Manufacturing TechnologyZhejiang University of TechnologyHangzhou 310000China School of Engineering London South Bank UniversityLondon SE10AAUK Shenzhen Jinzhou Precision Technology Corporation Shenzhen 518116China Department of Mechanical Engineering University of Petroleum and Energy StudiesDehradun 248007India Special Equipment Institute Hangzhou Vocational&Technical CollegeHangzhou 310018China

Printed circuit boards(PCBs)are representative composite materials,and their high-quality drilling machining remains a persistent challenge in the *** finishing of the cutting edge of a microdrill is crucial to drill performance in machining fine-quality holes with a prolonged tool *** miniature size involving submicron scale geometric dimensions,a complex flute shape,and low fracture toughness makes the cutting edge of microdrills susceptible to breakage and has been the primary limiting factor in edge preparation for *** this study,a newly developed cutting edge preparation method for microdrills was tested experimentally on electronic printed circuit *** proposed method,namely,shear thickening polishing,limited the cutting edge burrs and chipping on the cutting edge,and this in turn transformed the cutting edge’s radius from being sharp to ***,the edge–edge radius could be regulated by adjusting the processing *** drilling experiments were conducted to investigate the influence of different cutting edge radii on wear,hole position accuracy,nail head value,and hole wall *** proposed approach showed 20%enhancement in hole position accuracy,33%reduction in the nail head value,and 19%reduction in hole wall roughness compared with the original ***,a threshold is needed;without it,excessive shear thickening polishing will result in a blunt edge,which may accelerate the wear of the *** was identified as the primary factor that reduced hole *** study indicates that in printed circuit board machining,microdrills should effectively eliminate grinding defects and maintain the sharpness of the cutting edge as much as possible to obtain excellent drilling ***,shear thickening polishing is a promising method for cutting edge preparation of *** research and optimization can lead to additional improvements in microdrill performance and contribute to the conti

关键词： microdrill shear thickening polishing cutting edge preparation electronic printed circuit boards hole quality

Facile synthesis of thiazole cation functionalized core/shell magnetic microspheres for isolation of hemoglobin

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Facile synthesis of thiazole cation functionalized core/shel...

中国化学会第十九届全国有机分析及生物分析学术研讨会

作者： Juanqiang wang binghai wang Quan Li Yun Wei State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

＜正＞The selective separation of protein targets from complex biological samples is currently a hot topic in key life science disciplines（e.g.,diagnostics,proteomics,and protein purification）.Among these existing protocols,magnetic composite micro-（nano）spheres have attracted extensive attention due to their unique magnetic

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基于PPP的动对动定位技术与精度分析

测绘信息与工程 2009年第1期34卷 14-15页

作者：匡团结王兵海铁道第三勘察设计院集团有限公司天津市中山路10号300251

介绍了GPS精密单点定位和动对动实时差分定位技术,提出了基于GPS精密单点定位的动对动定位方法,实现了分米级的定位精度。

关键词：全球定位系统精密单点定位动对动定位

高速铁路自由测站三角高程测量代替CPⅢ精密水准测量的适用性分析

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铁道勘察 2018年第4期44卷 10-12页

作者：王兵海中国铁路设计集团有限公司天津300142

为分析CPⅢ自由测站三角高程测量代替精密水准测量的适用性,对比某高速铁路建设期水准测量成果及运营期CPⅢ自由测站三角高程测量和水准测量等三组数据的高程成果,结果表明,该项目中除有明显位移的CPⅢ点以外,相同CPⅢ点运营期与建设期... 详细信息

为分析CPⅢ自由测站三角高程测量代替精密水准测量的适用性,对比某高速铁路建设期水准测量成果及运营期CPⅢ自由测站三角高程测量和水准测量等三组数据的高程成果,结果表明,该项目中除有明显位移的CPⅢ点以外,相同CPⅢ点运营期与建设期精密水准成果之间的差值不超过10 mm;而运营期的三角高程成果与精密水准成果的差值为0~3 cm,由此判断自由测站三角高程测量成果在该试验项目中存在较大的误差。使用CPⅢ自由测站三角高程测量成果代替精密水准测量成果还需增加复核检测,不能完全代替精密水准测量作为高速铁路线上工程施工测量的高程基准。

关键词： CPⅢ 三角高程精密水准测量适用性分析

基于PointNet的地铁盾构隧道点云典型要素分割

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铁道建筑技术 2022年第12期 159-163页

作者：王兵海中铁第五勘察设计院集团有限公司北京102600

本文针对盾构隧道三维激光点云数据,利用PointNet点云识别算法,构建隧道要素分割的深度神经网络模型。基于各要素样本数据与隧道壁背景数据存在类别不平衡情况,首先通过InstanceHardnessThreshold算法对隧道壁数据进行采样,平衡类别比例... 详细信息

本文针对盾构隧道三维激光点云数据,利用PointNet点云识别算法,构建隧道要素分割的深度神经网络模型。基于各要素样本数据与隧道壁背景数据存在类别不平衡情况,首先通过InstanceHardnessThreshold算法对隧道壁数据进行采样,平衡类别比例,同时借助focal loss函数对PointNet网络进行优化,使其更加着重于样本数目较少要素类别的学习,以提升分割效果。结果表明,本文研究方法能有效分割出横向施工缝、环向施工缝、螺栓孔等盾构隧道典型要素,可为隧道可视化和模型分析提供重要支撑。

关键词：盾构隧道要素分割 PointNet focal loss InstanceHardnessThreshold采样

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高寒地区高铁长大隧道洞内控制测量

工程勘察 2022年第6期50卷 63-67页

作者：王兵海中铁第五勘察设计院集团有限公司北京102600

高寒地区隧道内外温差大,在冬季尤为明显,气温对导线网距离观测值影响显著,自由测站边角交会网的边长相对常规导线网较短,可降低温差对距离的影响。本文综合分析了新版《铁路工程测量规范》对普速铁路无砟轨道隧道洞内CPⅡ自由测站边角... 详细信息

高寒地区隧道内外温差大,在冬季尤为明显,气温对导线网距离观测值影响显著,自由测站边角交会网的边长相对常规导线网较短,可降低温差对距离的影响。本文综合分析了新版《铁路工程测量规范》对普速铁路无砟轨道隧道洞内CPⅡ自由测站边角交会网和洞内导线测量的技术要求,结合高寒地区高速铁路隧道工程建设洞内控制测量的实际需求,研究提出了使用CPⅡ自由测站边角交会网测量方法进行洞内控制测量的主要技术要求的建议。应用项目CPⅡ网满足建议的技术要求后,利用该CPⅡ网起算的CPⅢ网平差成果精度能满足现行《高速铁路工程测量规范》中CPⅢ点位中误差小于2mm等相关技术指标要求,测量成果表明自由测站边角交会网适用于高寒地区高铁长大隧道的洞内控制测量。

关键词： CPⅡ 自由测站边角交会网 CPⅢ 平面控制测量