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Low-field NMR micro coils based on printed circuit board technology

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Science China(Technological Sciences) 2014年第10期57卷 2082-2088页

作者： WU WeiPing LU RongSheng ZHOU XinLong ZHANG YunYi NI ZhongHua Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments Southeast University School of Mechanical Engineering Southeast University

Radiofrequency coil is one of the most important components for a nuclear magnetic resonance(NMR)*** this article,some planar micro coils with an inner diameter of 2 mm and number of turns that varied from 1 to 11 were investigated based on the printed circuit board(PCB)*** electrical characterization of micro coils show that self-resonant frequencies are larger than 200 ***,an NMR measurement platform with a static magnetic field of 0.66 T was constructed and the signal to noise ratio(SNR)values of the NMR were *** was found that the SNR is optimal when the turn number of the micro coils is six and the excitation time of a 90°pulse is 0.8?***,we used the micro coil with six turns to study the transverse relaxation rate of copper sulfate pentahydrate aqueous solution with different *** was found that the transverse relaxation rate is proportional to the solution *** from the micro coil were verified by measurements using a Bruker Minispec MQ60.

关键词： printed circuit board planar micro coil low-field nuclear magnetic resonance signal to noise ratio transverse relaxation rate

Stress Analysis of printed circuit board with Different Thickness and Composite Materials Under Shock Loading

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Computer Modeling in Engineering & Sciences 2020年第2期122卷 661-674页

作者： Kuan-Ting Liu Chun-Lin Lu Nyan-Hwa Tai Meng-Kao Yeh Department of Power Mechanical Engineering National Tsing Hua UniversityHsinchu30013Taiwan. Department of Materials Science and Engineering National Tsing Hua UniversityHsinchu30013Taiwan.

In this study,the deformation and stress distribution of printed circuit board(PCB)with different thickness and composite materials under a shock loading were analyzed by the finite element *** standard 8-layer PCB subjected to a shock loading 1500 g was evaluated ***,the finite element models of the PCB with different thickness by stacking various number of layers were *** addition to changing thickness,the core material of PCB was replaced from woven E-glass/epoxy to woven carbon fiber/epoxy for structural *** non-linear material property of copper foil was considered in the *** results indicated that a thicker PCB has lower stress in the copper foil in PCBs under the shock *** stress difference between the thicker PCB(2.6 mm)and thinner PCB(0.6 mm)is around 5%.Using woven carbon fiber/epoxy as core material could lower the stress of copper foil around 6.6%under the shock loading 1500 g for the PCB with 0.6 mm *** the other hand,the stress level is under the failure strength of PCBs with carbon fiber/epoxy core layers and thickness 2.6 mm when the peak acceleration changes from 1500 g to 5000 *** study could provide a reference for the design and proper applications of the PCB with different thickness and composite materials.

关键词： Stress analysis printed circuit board composite material finite element analysis shock loading.

Crushing performance and resource characteristicof printed circuit board scrap

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Journal of Central South University of Technology 2005年第5期12卷 552-555页

作者：王晖顾帼华戚云峰 School of Chemistry and Chemical Engineering Central South University Changsha 410083China School of Minerals Processing and Bioengineering Central South University Changsha 410083 China

The crushing performance of printed circuit board (PCB) was studied on several crushers. The results show that PCB is a material which is difficult to crush. The crushing performance of PCB with disk crusher, especially vibration grinding, which has cut or impact action, excels that of jaw crusher or roller crusher. The PCB scrap is worthwhile to recycle using variety of modern characterization methods. When compared with natural resources, this material stream remains a rich precious metal and nonferrous metals. In PCB scrap, metals account for 47% of the total material composition, in which there exists 19.66% copper, 11.47% iron, 3.93% lead, 300 g/t gold and 510 kg/t silver, etc. In addition, the PCB scrap contains 27% of plastics and 26% of refractory oxides.

关键词： electronic scrap printed circuit board crushing recycling

Surface Breakdown of printed circuit board under Magnetic Field with Reduced Pressure

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Transactions of Tianjin University 2010年第1期16卷 6-10页

作者：杜伯学朱晓辉高宇卢欣 Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin Electrical Power Science Research Institute

Epoxy resin laminate onto which a pair of copper foil was printed was employed as test *** samples were placed in an artificial atmospheric chamber, which was vacuumed by a rotary pump from 100 kPa to 5 *** magnetic field was produced by permanent magnets that were assembled to make E×B drift away from, into and parallel to the sample surface, *** flux density was adjusted at 120 mT, 180 mT and 240 mT *** applying a negative bias voltage between the electrodes, the ...

关键词： printed circuit board surface breakdown magnetic field ambient pressure

An Improved Randomized Circle Detection Algorithm Using in printed circuit board Locating Mark

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Applied Mathematics 2019年第10期10卷 848-861页

作者： Jingkun Liu Qi Fan Chengyi University College Jimei UniversityXiamenChina Xiamen Sinic-Tek Intelligent Technology Co. Ltd.XiamenChina

This paper presents an improved Randomized Circle Detection (RCD) algorithm with the characteristic of circularity to detect randomized circle in images with complex background, which is not based on the Hough Transform. The experimental results denote that this algorithm can locate the circular mark of printed circuit board (PCB).

关键词： Circle Detection Randomized Algorithm Characteristic of Circularity printed circuit board

Study on Pyrolysis Process for Recycling Waste printed circuit board

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Study on Pyrolysis Process for Recycling Waste Printed Circu...

Detection Algorithm of Surface Defect Word on printed circuit board

第八届东亚资源再生技术国际会议

作者： J. Guan M.X. Lu W.G Dong W.J. Tian and L. Zhou Institute of Chemical and Environmental Engineering China University of Mining and Technology (Beijing) Beijing 100083

＜正＞The pyrolysis process as an alternative method for recycling waste printed circuit board （PCB） has been studied. The properties of solid residue, liquid and gas in the process were investigated. Results show that this process is effective to recover valuable products and energy from PCB, and the layered residue can be easily liberated for metal recovery.

关键词： printed circuit board electronic scrap pyrolysis.

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Computer Systems Science & Engineering 2023年第9期46卷 3911-3923页

作者： Min Zhang Haixu Xi School of Computer Engineering Jiangsu University of TechnologyChangzhou213001China

For printed circuit board(PCB)surface defect detection,traditional detection methods mostly focus on template matching-based reference method and manual detections,which have the disadvantages of low defect detection efficiency,large errors in defect identification and localization,and low versatility of *** order to furthermeet the requirements of high detection accuracy,real-time and interactivity required by the PCB industry in actual production *** the current work,we improve the Youonly-look-once(YOLOv4)defect detection method to train and detect six types of PCB small target ***,the original Cross Stage Partial Darknet53(CSPDarknet53)backbone network is preserved for PCB defect feature information extraction,and secondly,the original multi-layer cascade fusion method is changed to a single-layer feature layer structure to greatly avoid the problem of uneven distribution of priori anchor boxes size in PCB defect detection ***,the K-means++clustering method is used to accurately cluster the anchor boxes to obtain the required size requirements for the defect detection,which further improves the recognition and localization of small PCB ***,the improved YOLOv4 defect detection model is compared and analyzed on PCB dataset with multi-class *** experimental results show that the average detection accuracy value of the improved defect detection model reaches 99.34%,which has better detection capability,lower leakage rate and false detection rate for PCB defects in comparison with similar defect detection algorithms.

关键词： printed circuit board defect detection small target

Uncertain process-based data integration and residual lifetime evaluation of PCB in airborne equipment with ADT and field data

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Chinese Journal of Aeronautics 2024年第8期37卷 233-245页

作者： Yu WANG Rui KANG Linhan GUO Xiaoyang LI Zhe LIU Xiaohui WANG Weifang ZHANG Schoool of Reliability and Systems Engineering Beihang UniversityBeijing 100191China

Accurately evaluating the lifespan of the printed circuit board(PCB)in airborne equipment is an essential issue for aircraft design and operation in the marine atmospheric *** paper presents a novel evaluation method by fusing Accelerated Degradation Testing(ADT)data,degradation data,and life data of small samples based on the uncertainty degradation *** uncertain life model of PCB in airborne equipment is constructed by employing the uncertain distribution that considers the accelerated factor of multiple environmental conditions such as temperature,humidity,and *** addition,a degradation process model of PCB in airborne equipment is constructed by employing the uncertain process of fusing ADT data and field data,in which the performance characteristics of dynamic cumulative change are *** on minimizing the pth sample moments,an integrated method for parameter estimation of the PCB in airborne equipment is proposed by fusing the multi-source data of life,degradation,and *** engineering case illustrates the effectiveness and advantage of the proposed method.

关键词： printed circuit board Degradation Data integration Field environment Accelerated degradation testing Parameter estimate

A Single-board Integrated Millimeter-Wave Asymmetric Full-Digital Beamforming Array for B5G/6G Applications

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Engineering 2024年第10期41卷 35-50页

作者： Qingqing Lin Jun Xu Kai Chen Long Wang Wei Li Zhiqiang Yu Guangqi Yang Jianyi Zhou Zhe Chen Jixin Chen Xiaowei Zhu Wei Hong State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast UniversityNanjing 210096China Purple Mountain Laboratories Nanjing 211111China Frontiers Science Center for Mobile Information Communication and Security Southeast UniversityNanjing 210096China

In this article,a single-board integrated millimeter-wave(mm-Wave)asymmetric full-digital beamforming(AFDBF)array is developed for beyond-fifth-generation(B5G)and sixth-generation(6G)*** proposed integrated array effectively addresses the challenge of arranging a large number of ports in a full-digital array by designing vertical connections in a three-dimensional space and successfully integrating full-digital transmitting(Tx)and receiving(Rx)arrays independently in a single *** the traditional symmetric array,the proposed asymmetric array is composed of an 8×8 Tx array arranged in a square shape and an 8+8 Rx array arranged in an L *** center-to-center distance between two adjacent elements is 0.54k0 for both the Tx and Rx arrays,where k0 is the free-space wavelength at 27 *** proposed AFDBF array possesses a more compact structure and lower system hardware cost and power consumption compared with conventional brick-type full-digital *** addition,the energy efficiency of the proposed AFDBF array outperforms that of a hybrid beamforming *** measurement results indicate that the operating frequency band of the proposed array is 24.25–29.50 *** eight-element linear array within the Tx array can achieve a scanning angle ranging from-47°to+47°in both the azimuth and the elevation planes,and the measured scanning range of each eight-element Rx array is–45°to+45°.The measured maximum effective isotropic radiated power(EIRP)of the eight-element Tx array is 43.2 dBm at 28.0 GHz(considering the saturation point).Furthermore,the measured error vector magnitude(EVM)is less than 3%when 64-quadrature amplitude modulation(QAM)waveforms are used.

关键词： Full-digital beamforming array Asymmetric structure Single-board integrated Beyond fifth-generation and sixthgeneration Millimeter-wave communication Complex modulation printed circuit board Vertical connection