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Effect of copper content on the pyrolysis process of organic components in waste printed circuit boards:Based on experimental and quantum chemical DFT simulations
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作者 Bin Li Biqin Shen +5 位作者 Ran Tao Chenwei Hu Yufeng Wu Haoran Yuan Jing Gu Yong Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第9期202-211,共10页
In recent years,scientists have become increasingly concerned in recycling electronic trash,particularly waste printed circuit boards(WPCBs).Previous research has indicated that the presence of Cu impacts the pyrolysi... In recent years,scientists have become increasingly concerned in recycling electronic trash,particularly waste printed circuit boards(WPCBs).Previous research has indicated that the presence of Cu impacts the pyrolysis of WPCBs.However,there may be errors in the experimental results,as printed circuit boards(PCBs)with copper and those without copper are produced differently.For this experiment,we blended copper powder with PCB nonmetallic resin powder in various ratios to create the samples.The apparent kinetics and pyrolysis properties of four resin powders with varying copper concentrations were compared using nonisothermal thermogravimetric analysis(TG)and thermal pyrolysis-gas chromatography mass spectrometry(Py-GC/MS).From the perspective of kinetics,the apparent activation energy of the resin powder in the pyrolysis reaction shows a rise(0.1<a<0.2)-stable(0.2<a<0.4)-accelerated increase(0.4<a<0.8)-decrease(0.8<a<0.9)process.After adding copper powder,the apparent activation energy changes more obviously when(0.2<a<0.4).In the early stage of the pyrolysis reaction(0.1<a<0.6),the apparent activation energy is reduced,but when a?0.8,it is much higher than that of the resin sample without copper.Additionally,it is discovered using thermogravimetric analysis and Py-GC/MS that copper shortens the temperature range of the primary pyrolysis reaction and prevents the creation of compounds containing bromine.This inhibition will raise the temperature at which compounds containing bromine first form,and it will keep rising as the copper level rises.The majority of the circuit board molecules have lower bond energies when copper is present,according to calculations performed using the Gaussian09 software,which promotes the pyrolysis reaction. 展开更多
关键词 Waste printed circuit boards COPPER PYROLYSIS Kinetic study Density functional theory(DFT)
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High power triboelectric nanogenerator based on printed circuit board (PCB) technology 被引量:11
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作者 Changbao Han Chi Zhang +2 位作者 Wei Tang Xiaohui Li Zhong Lin Wang 《Nano Research》 SCIE EI CAS CSCD 2015年第3期722-730,共9页
Harvesting mechanical energy from our surroundings to acquire a steady and high power output has attracted intensive interest due to the fast development of portable electronics. In this work the disk-structured tribo... Harvesting mechanical energy from our surroundings to acquire a steady and high power output has attracted intensive interest due to the fast development of portable electronics. In this work the disk-structured triboelectric nanogenerator (TENG) was prepared based on the mature printed drcuit board (PCB) technology and the composite structure for effectively improving the utilization in space. A narrow grating of 1~ was designed to produce high output. Operated at a rotation rate of 1,000 rpm, the TENG produces a high output power density of 267 mW/cm2 (total power output of 25.7 W) at a matched load of 0.93 MfZ After introducing a transformer, the output power can be managed so that it can be directly used to charge a battery for a smart phone. With the PCB production technology, fabrication of high performance TENG at low cost and large-scale becomes feasible. 展开更多
关键词 triboelectric nanogenerator(TENG) printed circuit board (pcb output power TRANSFORMER
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Modeling of Micropores Drilling Force for Printed Circuit Board Micro-holes Based on Energy Method
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作者 郑小虎 阮浩 +2 位作者 陈宏博 刘骁佳 刘正好 《Journal of Donghua University(English Edition)》 CAS 2023年第5期525-530,共6页
The quality of printed circuit board(PCB)micro-hole processing directly determines the stability of the inner and outer circuit connections.Micro-hole drilling technology is a typical method for PCB micro-hole process... The quality of printed circuit board(PCB)micro-hole processing directly determines the stability of the inner and outer circuit connections.Micro-hole drilling technology is a typical method for PCB micro-hole processing.The problem of optimal control of its drilling force is one of the main factors affecting the quality of micro-hole machining.To address this problem,the thrust forces and torques in PCB drilling were first modeled and analyzed,and the corresponding prediction models were established.The drilling force analysis was carried out through the micro-hole drilling experiment,the specific cutting energy under different feed rates was calculated,the influence of the size effect was clarified,and the accuracy of the prediction model was verified.The result shows that during the drilling of glass fiber cloth,changes in the material removal mechanism are induced as the feed per revolution is varied.When the feed per revolution is less than the tool edge radius,the glass fiber is not cut by the main cutting edge,but is crushed and broken.When the feed per revolution is greater than the radius of the tool edge,the glass fiber is cut by the main cutting edge.At the same time,the established analytical model can accurately reflect the influence of the size effect on the drilling torque in PCB micro-hole drilling,and the error is within 10%.This method has certain practical application value in controlling PCB micro hole processing quality. 展开更多
关键词 printed circuit board(pcb) micro-hole drilling predictive model size effect multi-layer material
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Detection Algorithm of Surface Defect Word on Printed Circuit Board
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作者 Min Zhang Haixu Xi 《Computer Systems Science & Engineering》 SCIE EI 2023年第9期3911-3923,共13页
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 ... 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 detectionmethods.In order to furthermeet the requirements of high detection accuracy,real-time and interactivity required by the PCB industry in actual production life.In the current work,we improve the Youonly-look-once(YOLOv4)defect detection method to train and detect six types of PCB small target defects.Firstly,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 process.Then,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 defects.Finally,the improved YOLOv4 defect detection model is compared and analyzed on PCB dataset with multi-class algorithms.The 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. 展开更多
关键词 printed circuit board defect detection small target
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Optimization of low-temperature alkaline smelting process of crushed metal enrichment originated from waste printed circuit boards 被引量:5
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作者 郭学益 刘静欣 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1643-1650,共8页
A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used t... A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters,in which mass ratio of Na OH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and3 D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of Na OH-to-CME of4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process. 展开更多
关键词 low-temperature alkaline smelting waste printed circuit board amphoteric metals central composite design conversion
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Crushing performance and resource characteristicof printed circuit board scrap 被引量:7
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作者 王晖 顾帼华 戚云峰 《Journal of Central South University of Technology》 EI 2005年第5期552-555,共4页
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, especial... 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. 展开更多
关键词 electronic scrap printed circuit board CRUSHING RECYCLING
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Pyrolysis kinetics and TG-FTIR analysis of waste epoxy printed circuit boards 被引量:4
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作者 湛志华 丘克强 《Journal of Central South University》 SCIE EI CAS 2011年第2期331-336,共6页
Thermal decomposition of waste epoxy PCBs was performed in different atmospheres (nitrogen, argon, air and vacuum) at a heating rate of 10 ℃/rain by DSC-TGA, and the pyrolysis characteristic was analyzed. The gases... Thermal decomposition of waste epoxy PCBs was performed in different atmospheres (nitrogen, argon, air and vacuum) at a heating rate of 10 ℃/rain by DSC-TGA, and the pyrolysis characteristic was analyzed. The gases volatilized from the experiment were qualitatively analyzed by TG-FTIR. Kinetics study shows that pyrolysis reaction takes place between 300 and 400℃, and the activation energies are 256, 212 and 186.2 kJ/mol in nitrogen, argon and vacuum, respectively. There are two mass-loss processes in the decomposition under air atmosphere. In the first mass-loss process, the decomposition is the main reaction, and in the second process, the oxidation is the main reaction. The activation energy of the second mass-loss process is 99.6 kJ/mol by isothermal heat-treatments. TG-FTIR analysis shows carbon dioxide, carbon monoxide, hydrogen bromide, phenol and substituent phenol are given off during the pyrolysis of waste epoxy PCBs. 展开更多
关键词 PYROLYSIS KINETICS WASTE printed circuit boards
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A micro-chip exploding foil initiator based on printed circuit board technology 被引量:4
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作者 Zhi Yang Peng Zhu +4 位作者 Qing-yun Chu Qiu Zhang Ke Wang Hao-tian Jian Rui-qi Shen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第8期1435-1444,共10页
Conventional exploding foil initiator (EFI) in ignition or detonation applications hosts many performance advantages, but was hindered by the bulky, inaccurate, inefficient and expensive shortcomings. We highlight a n... Conventional exploding foil initiator (EFI) in ignition or detonation applications hosts many performance advantages, but was hindered by the bulky, inaccurate, inefficient and expensive shortcomings. We highlight a novel micro-chip exploding foil initiator (McEFI) using printed circuit board (PCB) technology. The structural parameters were determined based on energy coupling relationship at the component interfaces. Next, the prototype McEFI has been batch-fabricated using PCB technology, with a monolithic structure of 7.0 mm (l) × 4.5 mm (w) × 4.0 mm (δ). As expected, this PCB-McEFI illustrated the successful firing validations for explosives pellets. This paper has addressed the cost problem in both military munitions and civil markets wherever reliable, insensitive and timing-dependent ignition or detonation are involved. 展开更多
关键词 Exploding foil initiator printed circuit board Monolithic structure Firing validations
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Efficient recovery of valuable metals from waste printed circuit boards by microwave pyrolysis 被引量:4
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作者 Yubo Liu Jialiang Zhang +3 位作者 Xu Yang Wenguang Yang Yongqiang Chen Chengyan Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第12期262-268,共7页
The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals ... The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals Cu, Sn and Pb were recovered from the pyrolyzed WPCBs. The effect of pyrolysis temperature and time on the recovery efficiency of valuable metals was investigated. Additionally, the characterization for morphology and surface elemental distribution of pyrolysis residues was carried out to investigate the pyrolysis mechanism. The plastic fiber boards turned into black carbides, and they can be easily separated from the metals by manual. The results indicate that 91.2%, 96.1% and 94.4% of Cu, Sn and Pb can be recovered after microwave pyrolysis at 700 °C for 60 minutes. After pyrolysis, about 79.8%(mass)solid products, 11.9%(mass) oil and 8.3%(mass) gas were produced. These gas and oil can be used as fuel and raw materials of organic chemicals, respectively. This process provides an efficient and energy-saving technology for recovering valuable metals from WPCBs. 展开更多
关键词 RECOVERY Waste printed circuit boards(Wpcbs) Microwave pyrolysis Valuable metals Waste treatment
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Study on High-power LED Heat Dissipation Based on Printed Circuit Board 被引量:2
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作者 WANG Yiwei ZHANG Jianxin +1 位作者 NIU Pingjuan LI Jingyi 《Semiconductor Photonics and Technology》 CAS 2010年第2期121-125,共5页
In order to study the role of printed circuit board(PCB)in high-power LED heat dissipation,a simple model of high-power LED lamp was designed.According to this lamp model,some thermal performances such as thermal resi... In order to study the role of printed circuit board(PCB)in high-power LED heat dissipation,a simple model of high-power LED lamp was designed.According to this lamp model,some thermal performances such as thermal resistances of four types of PCB and the changes of LED junction temperature were tested under three different working currents.The obtained results indicate that LED junction temperature can not be lowered significantly with the decreasing thermal resistance of PCB.However,PCB with low thermal resistance can be matched with smaller volume heat sink,so it is hopeful to reduce the size,weight and cost of LED lamp. 展开更多
关键词 high-power LED printed circuit board(pcb) substrate of heat dissipation thermal resistance junction temperature
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Pyrolysis behaviour and combustion kinetics of waste printed circuit boards 被引量:2
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作者 Kang Yan Chongwei Liu +6 位作者 Liping Liu Min Xiong Jiongtong Chen Zhongtang Zhang Shuiping Zhong Zhifeng Xu Jindi Huang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2022年第9期1722-1732,共11页
The effective recycling of waste printed circuit boards(WPCBs)can conserve resources and reduce environmental pollution.This study explores the pyrolysis and combustion characteristics of WPCBs in various atmospheres ... The effective recycling of waste printed circuit boards(WPCBs)can conserve resources and reduce environmental pollution.This study explores the pyrolysis and combustion characteristics of WPCBs in various atmospheres through thermogravimetric and Gaussian fitting analyses.Furthermore,this study analyses the pyrolysis products and combustion processes of WPCBs through thermogravimetric and Fourier transform infrared analyses(TG-FTIR)and thermogravimetry-mass spectrometry(TG-MS).Results show that the pyrolysis and combustion processes of WPCBs do not constitute a single reaction,but rather an overlap of multiple reactions.The pyrolysis and combustion process of WPCBs is divided into multiple reactions by Gaussian peak fitting.The kinetic parameters of each reaction are obtained by the Coats-Redfern method.In an argon atmosphere,pyrolysis consists of the overlap of the preliminary pyrolysis of epoxy resin,pyrolysis of small organic molecules,and pyrolysis of brominated flame retardants.The thermal decomposition process in the O_(2) atmosphere is mainly divided into two reactions:brominated flame retardant combustion and epoxy combustion.This study provided the theoretical basis for pollution control,process optimization,and reactor design of WPCBs pyrolysis. 展开更多
关键词 waste printed circuit board pyrolysis mechanism COMBUSTION GAUSS peak fitting
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Recovery of Gold, Silver, Copper and Niobium from Printed Circuit Boards Using Leaching Column Technique 被引量:3
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作者 Ricardo Montero Alicia Guevara Ernesto de la Torre 《Journal of Earth Science and Engineering》 2012年第10期590-595,共6页
Nowadays, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc.. After the use-phase, the electronic devices become electronic was... Nowadays, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc.. After the use-phase, the electronic devices become electronic waste (e-waste); consequently it is important to consider e-waste as a secondary supply for the recovery of these metals. This paper presents the recovery ofAu, Ag, Cu and Nb from PCBs (printed circuit boards) of discarded computers using leaching column technique. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm, Then, it was leached with a sodium cyanide solution in a glass column using the following conditions: sodium cyanide concentration 4 g/L, flux 20 L/d kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained: Au 46.6%, Ag 51.3%, Nb 47.2% and Cu 62.3%. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of USS155,639, considering the recovered metals from the loaded carbon. The internal rate of return for a 10 years period IRR (internal rate of return) and NPV (net present value) estimated are 27% and US$105,926 respectively. 展开更多
关键词 printed circuit boards RECOVERY precious metals niobium.
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Study on Metals Recovery from -0.074 mm Printed Circuit Boards by Enhanced Gravity Separation 被引量:9
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作者 赵跃民 温雪峰 +2 位作者 施红霞 焦红光 陶有俊 《过程工程学报》 EI CAS CSCD 北大核心 2006年第2期201-204,共4页
Nowadays study on reutilization of discarded printed circuit boards (PCBs) has great significance for achieving secondary resources recycling and preventing environmental pollution. Physical methods show great potenti... Nowadays study on reutilization of discarded printed circuit boards (PCBs) has great significance for achieving secondary resources recycling and preventing environmental pollution. Physical methods show great potential and advantages on discarded PCBs reutilization, compared with chemical and biological methods. However for the particles of 0.074 mm PCBs, little work has been done in the past because of lower separation efficiency and recovery. In this work, the conundrum of 0.074 mm PCBs reutilization was resolved successfully with the help of Falcon concentrator. Separation mechanism for fine particles with different mass densities in a Falcon centrifugal concentrator was analyzed. The main factors such as magnitude of rotation frequency (centrifugal acceleration), anti-charge water pressure and feeding concentration were studied, and interaction of different factors was analyzed using DesignExpert software. The experimental results show that metals grade of 0.074 mm PCBs and integration efficiency were obtained as 76.89% and 80.77% respectively when feeding concentration was 40 g/L with water pressure of 0.01 MPa and rotation frequency of 50 Hz. 展开更多
关键词 印刷电路板 重力分离 选矿 综合利用
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Supergravity separation of Pb and Sn from waste printed circuit boards at different temperatures 被引量:4
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作者 Long Meng Zhe Wang +2 位作者 Yi-wei Zhong Kui-yuan Chen Zhan-cheng Guo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第2期173-180,共8页
Printed circuit boards(PCBs) contain many toxic substances as well as valuable metals, e.g., lead(Pb) and tin(Sn). In this study, a novel technology, named supergravity, was used to separate different mass ratio... Printed circuit boards(PCBs) contain many toxic substances as well as valuable metals, e.g., lead(Pb) and tin(Sn). In this study, a novel technology, named supergravity, was used to separate different mass ratios of Pb and Sn from Pb–Sn alloys in PCBs. In a supergravity field, the liquid metal phase can permeate from solid particles. Hence, temperatures of 200, 280, and 400°C were chosen to separate Pb and Sn from PCBs. The results depicted that gravity coefficient only affected the recovery rates of Pb and Sn, whereas it had little effect on the mass ratios of Pb and Sn in the obtained alloys. With an increase in gravity coefficient, the recovery values of Pb and Sn in each step of the separation process increased. In the single-step separation process, the mass ratios of Pb and Sn in Pb–Sn alloys were 0.55, 0.40, and 0.64 at 200, 280, and 400°C, respectively. In the two-step separation process, the mass ratios were 0.12 and 0.55 at 280 and 400°C, respectively. Further, the mass ratio was observed to be 0.76 at 400°C in the three-step separation process. This process provides an innovative approach to the recycling mechanism of Pb and Sn from PCBs. 展开更多
关键词 printed circuit boards supergravity separation recovery Pb–Sn alloy gravity coefficient
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Metals Recovery from Fine Printed Circuit Boards Using Falcon SB Concentrator 被引量:2
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作者 WEN Xue-feng ZHAO Yue-min +3 位作者 PAN Yan-jun HE Ya-qun SONG Shu-lei WANG Zhuo-ya 《Journal of China University of Mining and Technology》 EI 2005年第4期322-328,共7页
Physical methods show great potential and advantages on comprehensive reutilization of waste printed circuit boards (PCBs) because of lower investment and operation cost, higher efficiency and environment friendliness... Physical methods show great potential and advantages on comprehensive reutilization of waste printed circuit boards (PCBs) because of lower investment and operation cost, higher efficiency and environment friendliness. However, metals contained in fine fraction of PCBs cannot be recovered effectively by conventional equipments such as high tension electrostatic separator or shaking table. In the paper, this conundrum was resolved successfully with the enhanced Falcon SB concentrator. The separation mechanism of Falcon SB concentrator was analyzed and main factors affecting separation efficiency such as magnitude of rotation frequency of bowl, water counter pressure and slurry concentration of feed were studied and interaction of factors above also were investigated using Design-Expert software. Experiment results show that complete liberation degree and great difference of density between metals and nonmetals are suitable to recover metals from -74 μm PCBs using enhanced Falcon SB concentrator and 80.77 % integration efficiency can be achieved when slurry concentration of feed is 40 g/L with the water counter pressure of 0.01 MPa and rotation frequency of 50 Hz. 展开更多
关键词 Falcon concentrator centrifugal separation waste printed circuit boards integration efficiency
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Fabrication of integrated resistors in printed circuit boards 被引量:1
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作者 王守国 陈清远 《Journal of Central South University》 SCIE EI CAS 2011年第3期739-743,共5页
In order to utilize integrated passive technology in printed circuit boards (PCBs), manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmeg... In order to utilize integrated passive technology in printed circuit boards (PCBs), manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmega technologies in the experiment were 1 408 pieces per panel with four different patterns A, B, C and D and four resistance values of 25, 50, 75 and 100 fL Six panel per batch and four batches were performed totally. The testing was done for 960 pieces of integrated resistors randomly selected with the same size. The value distribution ranges and the relative standard deviation (RSD) show that the scatter degree of the resistance decreases with the resistor size increasing and/or with the resistance increasing. Patterns D with resistance of 75 and 100% for four patterns have the resistance value variances less than 10%. Patterns C and D with resistance of 100 Ω have the manufacturing tolerance less than 10%. The process capabilities are from about 0.6 to 1.6 for the designed testing patterns, which shows that the integrated resistors fabricated have the potential to be used in multilayer PCBs in the future. 展开更多
关键词 integrated resistors lamination method printed circuit boards integrated passive technology
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10 Gb/s Optical Interconnection on Flexible Optical Waveguide in Electronic Printed Circuit Board 被引量:2
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作者 Shih-Hsiang Hsu Chih-Yuan Tsou +1 位作者 Chih-Ming Wang Sheng-Chieh Tseng 《Optics and Photonics Journal》 2013年第2期252-255,共4页
In this paper, we proposed 10 Gb/s transmission using 4-channel polymer waveguides on the optical electronic printed circuit board. It was simulated by the ray tracing method for tolerance study of optical interconnec... In this paper, we proposed 10 Gb/s transmission using 4-channel polymer waveguides on the optical electronic printed circuit board. It was simulated by the ray tracing method for tolerance study of optical interconnection and fabrication. In order for easy fabrication and high position accuracy, the polymer waveguides were forming silver coated 45° reflective mirrors by dicing method and e-beam deposition for 90° light beam turning. The coupling loss was demonstrated in different polishing grit sizes. The optical interconnection in board-embed 4-channel flexible waveguides was demonstrated with a low propagation loss of 0.1 dB/cm and a clear eye diagram at 2.5 Gb/s data rate per channel. 展开更多
关键词 FLEXIBLE WAVEGUIDE Optical ELECTRONIC printed circuit board
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Numerical Analysis of Printed Circuit Board with Thermal Vias: Heat Transfer Characteristics under Nonisothermal Boundary Conditions 被引量:1
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作者 Yasushi Koito Yoshihiro Kubo Toshio Tomimura 《Journal of Electronics Cooling and Thermal Control》 2013年第4期136-143,共8页
A thermal via has been used to enhance the heat transfer through the printed circuit board (PCB). Because the thermal conductivity of a dielectric material is very low, the array of metal vias is placed to make therma... A thermal via has been used to enhance the heat transfer through the printed circuit board (PCB). Because the thermal conductivity of a dielectric material is very low, the array of metal vias is placed to make thermal paths in the PCB. This paper describes the numerical analysis of the PCB having metal vias and focuses on the heat transfer characteristics under the nonisothermal boundary conditions. The mathematical model of the PCB has the metal vias between two metal sheets. Under 2nd and 3rd kinds of boundary conditions, the temperature distribution is obtained numerically by changing the design parameters. The discussion is also made on the effective thermal conductivity of the PCB. In industry, the use of effective thermal conductivity is convenient for thermal engineers because it simplifies the calculation process, that is, the composite board can be modeled as a homogeneous medium. From the numerical results, it is confirmed that the placement of metal sheets and the population of metal vias are important factors to dominate the heat transfer characteristics of the PCB. It is also shown that although the nonisothermal boundary conditions are applied at the boundary surface, the temperature difference between the heated and the cooled section is almost uniform when the metal vias are populated densely with the metal sheets. In this case, the effective thermal conductivity of the PCB is found to be the same irrespective of the boundary conditions, that is, whether the isothermal or the nonisothermal boundary conditions are applied. 展开更多
关键词 THERMAL Management printed circuit board THERMAL Via Effective THERMAL CONDUCTIVITY NONISOTHERMAL Boundary Condition
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An Improved Randomized Circle Detection Algorithm Using in Printed Circuit Board Locating Mark 被引量:2
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作者 Jingkun Liu Qi Fan 《Applied Mathematics》 2019年第10期848-861,共14页
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 Transfo... 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). 展开更多
关键词 Circle Detection Randomized Algorithm Characteristic of Circularity printed circuit board
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Recycling process assessment of mechanical recycling of printed circuit board
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作者 潘君齐 刘志峰 +2 位作者 刘光复 王淑旺 黄海鸿 《Journal of Central South University》 SCIE EI CAS 2005年第S2期157-161,共5页
A comprehensive assessment index system was established. The mechanical recycling process of printed circuit board was evaluated according to the comprehensive evaluation index system using the fuzzy analytic hierarch... A comprehensive assessment index system was established. The mechanical recycling process of printed circuit board was evaluated according to the comprehensive evaluation index system using the fuzzy analytic hierarchy process. A process assessment software system of mechanical recycling was established to evaluate different recycling technologies. And the software system was developed in the environment of VB6.0 and Access2000. 展开更多
关键词 printed circuit board mechanical RECYCLING PROCESS ASSESSMENT fuzzy ANALYTIC HIERARCHY PROCESS
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