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Self-catalytic pyrolysis thermodynamics of waste printed circuit boards with co-existing metals

《环境科学与工程前沿(英文)》 2022年 第16卷 第11期 doi: 10.1007/s11783-022-1581-0

摘要:

● The co-existing metals in WPCBs has positive catalytic influence in pyrolysis.

关键词: Waste printed circuit board     Catalyst     Pyrolysis     Kinetics    

Non-toxic, high selectivity process for the extraction of precious metals from waste printed circuit

《环境科学与工程前沿(英文)》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1723-z

摘要:

● Au, Ag and Pd were recovered from WPCBs with high efficiencies.

关键词: Thiosulfate     Printed circuit boards     Precious metals     Leaching     Hydrometallurgy    

单边直线感应电机等效电路参数研究

徐伟,孙广生

《中国工程科学》 2008年 第10卷 第8期   页码 76-80

摘要:

单边直线感应电机(SLIM)相对于旋转感应电机(RIM)存在气隙大、边缘效应等,若采用RIM开路和短路试验方法,会给参数测量带来较大误差。文章提出的一种适合SLIM参数测定的新型方案,只需测量电机输入端的总功率、相电压、相电流和频率4个量,即可计算出初级电阻、初级漏感、次级电阻、次级漏感、气隙电感和铁损电阻。电机的特性分析表明,该方法真实有效,具有一定的参考价值。

关键词: 单边直线感应电机     开路试验     短路试验     参数测量     等效电路    

Equivalent circuit and characteristic simulation of a brushless electrically excited synchronous wind

Hao WANG, Fengge ZHANG, Tao GUAN, Siyang YU

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 420-426 doi: 10.1007/s11465-017-0439-9

摘要:

A brushless electrically excited synchronous generator (BEESG) with a hybrid rotor is a novel electrically excited synchronous generator. The BEESG proposed in this paper is composed of a conventional stator with two different sets of windings with different pole numbers, and a hybrid rotor with powerful coupling capacity. The pole number of the rotor is different from those of the stator windings. Thus, an analysis method different from that applied to conventional generators should be applied to the BEESG. In view of this problem, the equivalent circuit and electromagnetic torque expression of the BEESG are derived on the basis of electromagnetic relation of the proposed generator. The generator is simulated and tested experimentally using the established equivalent circuit model. The experimental and simulation data are then analyzed and compared. Results show the validity of the equivalent circuit model.

关键词: wind power     brushless electrically excited synchronous generator     hybrid rotor     equivalent circuit    

Copper recovery from waste printed circuit boards concentrated metal scraps by electrolysis

Xiaonan Liu, Qiuxia Tan, Yungui Li, Zhonghui Xu, Mengjun Chen

《环境科学与工程前沿(英文)》 2017年 第11卷 第5期 doi: 10.1007/s11783-017-0997-4

摘要: Copper recovery is the core of waste printed circuit boards (WPCBs) treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis and factors that affect copper recovery rate and purity, mainly CuSO ·5H O concentration, NaCl concentration, H SO concentration and current density, were discussed in detail. The results indicated that copper recovery rate increased first with the increase of CuSO ·5H O NaCl, H SO and current density and then decreased with further increasing these conditions. NaCl, H SO and current density also showed a similar impact on copper purity, which also increased first and then decreased. Copper purity increased with the increase of CuSO ·5H O. When the concentration of CuSO ·5H O, NaCl and H SO was respectively 90, 40 and 118 g/L and current density was 80 mA/cm , copper recovery rate and purity was up to 97.32% and 99.86%, respectively. Thus, electrolysis proposes a feasible and prospective approach for waste printed circuit boards recycle, even for e-waste, though more researches are needed for industrial application.

关键词: Waste printed circuit boards (WPCBs)     Copper     Recovery rate     Purity     Electrolysis    

Copper fractal growth during recycling from waste printed circuit boards by slurry electrolysis

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1405-7

摘要:

• Copper fractal growth was observed during WPCBs recycling by slurry electrolysis.

关键词: Dendritic copper     Fractal growth     WPCBs     Slurry electrolysis    

Multiobjective trajectory optimization of intelligent electro-hydraulic shovel

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0706-2

摘要: Multiobjective trajectory planning is still face challenges due to certain practical requirements and multiple contradicting objectives optimized simultaneously. In this paper, a multiobjective trajectory optimization approach that sets energy consumption, execution time, and excavation volume as the objective functions is presented for the electro-hydraulic shovel (EHS). The proposed cubic polynomial S-curve is employed to plan the crowd and hoist speed of EHS. Then, a novel hybrid constrained multiobjective evolutionary algorithm based on decomposition is proposed to deal with this constrained multiobjective optimization problem. The normalization of objectives is introduced to minimize the unfavorable effect of orders of magnitude. A novel hybrid constraint handling approach based on -constraint and the adaptive penalty function method is utilized to discover infeasible solution information and improve population diversity. Finally, the entropy weight technique for order preference by similarity to an ideal solution method is used to select the most satisfied solution from the Pareto optimal set. The performance of the proposed strategy is validated and analyzed by a series of simulation and experimental studies. Results show that the proposed approach can provide the high-quality Pareto optimal solutions and outperforms other trajectory optimization schemes investigated in this article.

关键词: trajectory planning     electro-hydraulic shovel     cubic polynomial S-curve     multiobjective optimization     entropy weight technique    

Enhancement of open circuit voltage in organic solar cells by doping a fluorescent red dye

Qing LI, Junsheng YU, Yue ZANG, Nana WANG, Yadong JIANG

《能源前沿(英文)》 2012年 第6卷 第2期   页码 179-183 doi: 10.1007/s11708-012-0177-y

摘要: The open circuit voltage ( ) of small-molecule organic solar cells (OSCs) could be improved by doping suitable fluorescent dyes into the donor layers. In this paper, 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) was used as a dopant, and the performance of the OSCs with different DCJTB concentration in copper phthalocyanine (CuPc) was studied. The results showed that the of the OSC with 50% of DCJTB in CuPc increased by 15%, compared with that of the standard CuPc/fullerene (C ) device. The enhancement of the was attributed to the lower highest occupied molecular orbital (HOMO) level in the DCJTB than that in the CuPc. Also, the light absorption intensity is enhanced between 400 and 550 nm, where CuPc and C have low absorbance, leading to a broad absorption spectrum.

关键词: organic solar cells (OSCs)     open circuit voltage     fluorescent dye doping     4-(dicyanomethylene)-2-t-butyl-6-(1     1     7     7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB)    

Effects of slip length and hydraulic diameter on hydraulic entrance length of microchannels with superhydrophobic

Wenchi GONG, Jun SHEN, Wei DAI, Zeng DENG, Xueqiang DONG, Maoqiong GONG

《能源前沿(英文)》 2020年 第14卷 第1期   页码 127-138 doi: 10.1007/s11708-020-0661-8

摘要: This paper investigated effects of slip length and hydraulic diameter on the hydraulic entrance length of laminar flow in superhydrophobic microchannels. Numerical investigations were performed for square microchannels with Re ranging between 0.1 and 1000. It is found that superhydrophobic microchannels have a longer hydraulic entrance length than that of conventional ones by nearly 26.62% at a low Re. The dimensionless hydraulic entrance length slightly increases with the increasing slip length at approximately Re<10, and does not vary with the hydraulic diameter. A new correlation to predict the entrance length in square microchannels with different slip lengths was developed, which has a satisfying predictive performance with a mean absolute relative deviation of 5.69%. The results not only ascertain the flow characteristics of superhydrophobic microchannels, but also suggest that super hydrophobic microchannels have more significant advantages for heat transfer enhancement at a low Re.

关键词: laminar flow     hydraulic entrance length     super hydrophobic surface     slip length     hydraulic diameter    

Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom

《环境科学与工程前沿(英文)》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1564-1

摘要:

● A new model for bloom control in open land scape water was constructed.

关键词: Reclaimed water landscape     Algal bloom     Nitrogen and phosphorus     Hydraulic retention time     Threshold     Control model    

A critical review on the recycling of copper and precious metals from waste printed circuit boards using

Zebing Wu, Wenyi Yuan, Jinhui Li, Xiaoyan Wang, Lili Liu, Jingwei Wang

《环境科学与工程前沿(英文)》 2017年 第11卷 第5期 doi: 10.1007/s11783-017-0995-6

摘要: Currently, increasing amounts of end-of-life (EoL) electronic products are being generated due to their reduced life spans and the unavailability of suitable recycling technologies. In particular, waste printed circuit boards (PCBs) have become of global concern with regard to environmental issues because of their high metal and toxic material contents, which are pollutants. There are many environmental threats owed to the disposal of electronic waste; off-gasses, such as dioxins, furans, polybrominated organic pollutants, and polycyclic aromatic hydrocarbons, can be generated during thermal treatments, which can cause serious health problems if effective off-gas cleaning systems are not developed and improved. Moreover, heavy metals will dissolve, and release into the ground water from the landfill sites. Such waste PCBs contain precious metals which are of monetary value. Therefore, it is beneficial to recover the metal content and protect the environment from pollution. Hydrometallurgy is a successful technique used worldwide for the recovery of precious metals (especially gold and silver) from ores, concentrates, and waste materials. It is generally preferred over other methods because it can offer high recovery rates at a relatively low cost. This article reviews the recent trends and developments with regard to the recycling of precious metals from waste PCBs through hydrometallurgical techniques, such as leaching and recovery.

关键词: Waste PCBs     Precious metals     Hydrometallurgy     Recycling     Leaching     Recovery    

Proportional directional valve based automatic steering system for tractors Project supported by the Synergistic Innovation Center of Modern Agricultural Equipment and Technology, China (No. NZXT01201401)

Jin-yi LIU,Jing-quan TAN,En-rong MAO,Zheng-he SONG,Zhong-xiang ZHU

《信息与电子工程前沿(英文)》 2016年 第17卷 第5期   页码 458-464 doi: 10.1631/FITEE.1500172

摘要: Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3- position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressurecompensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative (PID) running on a 51-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoidal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods.

关键词: Automatic steering system     Hydraulic circuit     Proportional directional valve     Proportional-integral-derivative (PID) control    

Hydromechanical model for hydraulic fractures using XFEM

Bo HE

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 240-249 doi: 10.1007/s11709-018-0490-6

摘要: In this study, a hydromechanical model for fluid flow in fractured porous media is presented. We assume viscous fluids and the coupling equations are derived from the mass and momentum balance equations for saturated porous media. The fluid flow through discrete cracks will be modelled by the extended finite element method and an implicit time integration scheme. We also present a consistent linearization of the underlying non-linear discrete equations. They are solved by the Newton-Raphson iteration procedure in combination with a line search. Furthermore, the model is extended to includes crack propagation. Finally, examples are presented to demonstrate the versatility and efficiency of this two-scale hydromechanical model. The results suggest that the presence of the fracture in a deforming, porous media has great impact on the fluid flow and deformation patterns.

关键词: multi-phase medium     porous     fracture     multi-scale method    

Review of fluid and control technology of hydraulic wind turbines

Maolin CAI, Yixuan WANG, Zongxia JIAO, Yan SHI

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 312-320 doi: 10.1007/s11465-017-0433-2

摘要:

This study examines the development of the fluid and control technology of hydraulic wind turbines. The current state of hydraulic wind turbines as a new technology is described, and its basic fluid model and typical control method are expounded by comparing various study results. Finally, the advantages of hydraulic wind turbines are enumerated. Hydraulic wind turbines are expected to become the main development direction of wind turbines.

关键词: wind turbine     hydraulic system     fluid model     control technology    

current measurement of the thickness of top Cu film of the multilayer interconnects in the integrated circuit

Zilian QU,Yonggang MENG,Qian ZHAO

《机械工程前沿(英文)》 2015年 第10卷 第1期   页码 1-6 doi: 10.1007/s11465-015-0325-2

摘要:

This paper proposes a new eddy current method, named equivalent unit method (EUM), for the thickness measurement of the top copper film of multilayer interconnects in the chemical mechanical polishing (CMP) process, which is an important step in the integrated circuit (IC) manufacturing. The influence of the underneath circuit layers on the eddy current is modeled and treated as an equivalent film thickness. By subtracting this equivalent film component, the accuracy of the thickness measurement of the top copper layer with an eddy current sensor is improved and the absolute error is 3 nm for sampler measurement.

关键词: CMP     eddy current     multilayer wafer     Cu interconnects     equivalent unit    

标题 作者 时间 类型 操作

Self-catalytic pyrolysis thermodynamics of waste printed circuit boards with co-existing metals

期刊论文

Non-toxic, high selectivity process for the extraction of precious metals from waste printed circuit

期刊论文

单边直线感应电机等效电路参数研究

徐伟,孙广生

期刊论文

Equivalent circuit and characteristic simulation of a brushless electrically excited synchronous wind

Hao WANG, Fengge ZHANG, Tao GUAN, Siyang YU

期刊论文

Copper recovery from waste printed circuit boards concentrated metal scraps by electrolysis

Xiaonan Liu, Qiuxia Tan, Yungui Li, Zhonghui Xu, Mengjun Chen

期刊论文

Copper fractal growth during recycling from waste printed circuit boards by slurry electrolysis

期刊论文

Multiobjective trajectory optimization of intelligent electro-hydraulic shovel

期刊论文

Enhancement of open circuit voltage in organic solar cells by doping a fluorescent red dye

Qing LI, Junsheng YU, Yue ZANG, Nana WANG, Yadong JIANG

期刊论文

Effects of slip length and hydraulic diameter on hydraulic entrance length of microchannels with superhydrophobic

Wenchi GONG, Jun SHEN, Wei DAI, Zeng DENG, Xueqiang DONG, Maoqiong GONG

期刊论文

Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom

期刊论文

A critical review on the recycling of copper and precious metals from waste printed circuit boards using

Zebing Wu, Wenyi Yuan, Jinhui Li, Xiaoyan Wang, Lili Liu, Jingwei Wang

期刊论文

Proportional directional valve based automatic steering system for tractors Project supported by the Synergistic Innovation Center of Modern Agricultural Equipment and Technology, China (No. NZXT01201401)

Jin-yi LIU,Jing-quan TAN,En-rong MAO,Zheng-he SONG,Zhong-xiang ZHU

期刊论文

Hydromechanical model for hydraulic fractures using XFEM

Bo HE

期刊论文

Review of fluid and control technology of hydraulic wind turbines

Maolin CAI, Yixuan WANG, Zongxia JIAO, Yan SHI

期刊论文

current measurement of the thickness of top Cu film of the multilayer interconnects in the integrated circuit

Zilian QU,Yonggang MENG,Qian ZHAO

期刊论文