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Preparation of a permanent magnetic hypercrosslinked resin and assessment of its ability to remove organic

Wei WANG,Yan MA,Qing ZHOU,Chendong SHUANG,Mancheng ZHANG,Aimin LI

《环境科学与工程前沿（英文）》 2015年第9卷第1期页码 96-104 doi: 10.1007/s11783-014-0724-3

摘要： A rapid and effective method based on a novel permanent magnetic hypercrosslinked resin W150 was proposed for the removal of organic micropollutants in drinking water. W150 was prepared by suspension and post-crosslinking reaction and found to possess a high specific surface area of 1149.7 m ·g , a small particle size of 50 μm to 100 μm, and a saturation magnetization as high as 8 emu·g . W150 was used to eliminate nitrofurazone (NFZ) and oxytetracycline (OTC) from drinking water compared with commercial adsorbents XAD-4 and F400D. The adsorption kinetics of NFZ and OTC onto the three adsorbents well fitted the pseudo-second-order equation ( >0.972), and the adsorption isotherms were all well described by the Freundlich equation ( >0.851). Results showed that the reduction in adsorbent size and the enlargement in sorbent pores both accelerated adsorption. Moreover, the effect of particle size on adsorption was more significant than that of pore width. Given that the smallest particle size and the highest specific surface area were possessed by W150, it had the fastest adsorption kinetics and largest adsorption capacity for NFZ (180 mg·g ) and OTC (200 mg·g ). For the adsorbents with dominant micropores, the sorption of large-sized adsorbates decreased because of the inaccessible micropores. The solution pH and ionic strength also influenced adsorption.

关键词： permanent magnetic resin organic micropollutant pore size molecular size adsorption

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Design method and magnetic field analysis of axial-magnetized permanent magnet micromotor

YANG Jiewei, WU Yihui, JIA Hongguang, ZHANG Ping, WANG Shurong

《机械工程前沿（英文）》 2007年第2卷第3期页码 318-322 doi: 10.1007/s11465-007-0056-0

摘要： To investigate the impact of size on its performance in designing an axial-magnetized permanent magnet micro motor, the finite element method is adopted to simulate the magnetic field of the dual rotor motor, and the flux density wave form distributed in the airgap is obtained. The influence of the external dimensions, pole numbers and magnet thicknesses of the rotor, and the airgap distances on the flux density, are analyzed and analytical results are given. With the increase of the airgap distance, the flux density under more poles reduces more quickly than under fewer poles. With the increase of the magnet thickness, the flux density is a rising curve, and after the magnet thickness attains a certain point, the flux density is almost a constant. While reducing the diameter of the rotor, the decrease of the flux density slows down as magnet thickness is reduced. To avoid having a seriously distorted waveform, the distance between inner and outer radii of the rotor must be larger than 1.5 millimeter. Results of the magnetic field analysis can guide a microminiaturization of the motor. Moreover, the results are analyzed theoretically and the simulated values are almost consistent with the experimental values.

关键词： axial-magnetized permanent diameter constant certain magnetic

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Structure optimization for magnetic equipment of permanent magnet retarder

Bingfeng JIAO, Desheng LI, Yunkang SUI, Lezhi YE

《机械工程前沿（英文）》 2010年第5卷第4期页码 442-445 doi: 10.1007/s11465-010-0112-z

摘要： The main purpose of this research is to perform a magnetic analysis on the magnetic equipment of permanent magnet retarder (PMR) and optimize the structure of magnetic equipment with the commercial FEM software ANSYS and its design optimization module. The FEM model is built as an axisymmetric model according to the characteristics of the structure of magnetic equipment. Using this model, the magnetic field distribution and magnetic force are calculated by ANSYS. The mathematical model of structure optimization is also built. The design variables are structural parameters including the dimensions of permanent magnets and magnetic yoke, and the objective function is the magnetic force. The unconstrained optimization model takes the maximum value of magnetic force as the objective. A first-order optimization method is used to determine the optimum design of this problem. The optimization process works entirely with the ANSYS parametric design language (APDL). The design tools are used to understand design space and the behavior of the dependent variables. It is shown that designing a structure with the ANSYS optimization module and its design tools is an effective means to improve the structure.

关键词： optimization ANSYS permanent magnet retarder numerical simulation

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稀土永磁体的前景与展望 Review

J.M.D. Coey

《工程（英文）》 2020年第6卷第2期页码 118-130 doi: 10.1016/j.eng.2018.11.034

摘要：

稀土永磁是一项成熟的技术，但2011年稀土危机的冲击导致人们重新考量20世纪80年代和90年代的许多关于几乎不含稀土（或重稀土）的新型硬磁材料的想法。Nd-Fe-B永磁通过精心巧妙的优化，适用于需要以合理成本获得高性能的广泛应用领域。当需要高温稳定性时，Sm-Co是首选材料，而某些应用也逐渐开始使用Sm-Fe-N磁体。对这些基本材料的元素替代改进的范围已经进行了相当深入的探讨，同时制备技术对微观结构和磁滞现象的影响也已深入了解。上一代的一个很宏大的想法，即制备交换耦合硬/软纳米复合的各向异性磁体，来显著提高创纪录的磁能积。然而，事实证明这很难实现。尽管如此，该领域已取得发展，而其他领域的创新也在不断蓬勃发展。例如，电动私人交通已经从电动自行车发展到电驱动的汽车和卡车成为主流，并且由此可见，电动运输很有可能结束内燃机的主导地位。随着越来越清晰地了解特定永磁体的局限性，人们开始围绕它进行具有独创性和想象力的设计，并最有效地利用了可用的稀土资源混合物。此外，机器人技术正在吸引着巨大的新市场，而且人们才刚刚开始探索增材制造所提供的机会。提高磁体高温稳定性的新方法也正在开发中，并且具有其他有用特性的硬磁体的集成多功能性也正在设想中。这些研究课题将在本文中通过各种示例进行详细说明。

关键词：稀土永磁体，磁各向异性，矫顽力，能积，磁性复合材料，增材制造

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Statics of levitated vehicle model with hybrid magnets

Desheng LI, Zhiyuan LU, Tianwu DONG

《机械工程前沿（英文）》 2009年第4卷第1期页码 35-39 doi: 10.1007/s11465-009-0002-4

摘要： By studying the special characteristics of permanent and electronic magnets, a levitated vehicle model with hybrid magnets is established. The mathematical model of the vehicle is built based on its dynamics equation by studying its machine structure and working principle. Based on the model, the basic characteristics and the effect between the excluding forces from permanent magnets in three different spatial directions are analyzed, statics characteristics of the interference forces in three different spatial directions are studied, and self-adjusting equilibrium characteristics and stabilization are analyzed. Based on the structure above, the vehicle can levitate steadily by control system adjustment.

关键词： magnetic levitation permanent magnet modeling equilibrium

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无轴承永磁同步电机转子磁场定向控制系统研究

朱熀秋,巫亮,周阳,张腾超,邓建明

《中国工程科学》 2006年第8卷第6期页码 35-40

摘要：

无轴承永磁同步电机是具有磁悬浮轴承优点的一种新型电机；在阐述了无轴承永磁同步电机工作原理基础上，采用转子磁场定向控制策略，推导了无轴承永磁同步电机径向悬浮力和电机旋转部分数学模型；根据无轴承电机解耦控制的要求设计了无轴承永磁同步电机转子磁场定向矢量控制系统，并以数字信号处理器TMS320LF2407为核心，研制了矢量控制系统的硬件和软件。实验结果表明：电机工作在0～3000r/min范围内，转子悬浮稳定且电机转速连续可调。

关键词：无轴承永磁同步电机解耦控制数字信号处理器数字控制

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Control strategies for disinfection byproducts by ion exchange resin, nanofiltration and their sequential

《环境科学与工程前沿（英文）》 2023年第17卷第10期 doi: 10.1007/s11783-023-1725-x

摘要：

● Effects of AER adsorption and NF on DBP precursors, DBPs, and TOX were examined.

关键词： Disinfection byproducts Control Anion exchange resin Nanofiltration Cytotoxicity

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各向异性热压稀土永磁体的热变形机制及微磁结构研究

李卫,朱明刚

《中国工程科学》 2011年第13卷第10期页码 4-12

摘要：

重点研究制备工艺对各向异性热压稀土永磁体性能的影响，探讨了热压永磁体的热变形机理和数学描述模型，并尝试从微磁结构的角度研究各向异性纳米晶Nd-Fe-B磁体，揭示纳米晶粒之间的静磁和交换耦合相互作用、磁化和反磁化、热退磁等微观机制。获得了最佳磁性能为：Hcj=1 157 kA/m，Br=1.465 T，(BH)max=426 kJ/m³纳米晶Nd-Fe-B磁体。

关键词：纳米晶Nd-Fe-B辐向环热压－热变形各向异性微磁结构

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面向21世纪的稀土工业

杨遇春

《中国工程科学》 2000年第2卷第9期页码 91-100

摘要：

中国拥有世界上最丰富的稀土资源。1998年中国稀土氧化物（REO)的生产能力已达到20000 t,几乎为世界需求的2倍，严重依赖出口，出口童占生产童的2/3。文章论述了稀土在冶金、永磁、储氢合金、催化剂、固体氧化物燃料电池和激光材料等方面的应用进展；指出我国未来稀土工业的方向是开发髙技术含童和高附加值的产品，拓宽国内和国际市场。

关键词：稀土氧化物永磁材料储氢合金催化剂燃料电池激光材料

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Removal of dissolved oxygen from water using a Pd-resin based catalytic reactor

Wenxin SHI, Chongwei CUI, Liye ZHAO, Shuili YU, Xia YUN

《化学科学与工程前沿（英文）》 2009年第3卷第1期页码 107-111 doi: 10.1007/s11705-009-0154-0

摘要： The removal of dissolved oxygen (DO) from water was studied experimentally in a Pd-resin base catalyst reactor using purified hydrogen gas as a reducing agent. The effects of various operating conditions, such as hydrogen and water flow rates, height of the catalytic resin bed, temperature, pH value and run time, on the removal of DO, had been studied extensively. The results shows that DO could be removed by the reactor from ppm to ppb levels at ambient temperature. Increases of temperature, H gas rate and the height of the catalytic resin were helpful to improve the DO removal rate. The change of pH value from 4 to 12 resulted in no effect on DO removal. Reaction time was the key factor to control the DO removal efficiency. Only when the reaction time was longer than 2.3 minutes under the experimental conditions, could a very low DO level be achieved.

关键词： dissolved oxygen palladium catalytic reactor hydrogen resin

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Modeling and analysis of magnetic dipoles in weak magnetic field

WANG Zhaoxia, ZHANG Weimin, LIU Hongguang

《机械工程前沿（英文）》 2008年第3卷第2期页码 222-225 doi: 10.1007/s11465-008-0028-z

摘要： The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and locate the defect.

关键词： geomagnetic theory important criterion magnetic leakage normal component

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Three-dimensional electromagnetic analysis and design of permanent magnet retarder

Lezhi YE, Desheng LI, Bingfeng JIAO

《机械工程前沿（英文）》 2010年第5卷第4期页码 438-441 doi: 10.1007/s11465-010-0111-0

摘要： An eddy current retarder for vehicles generates much heat when it works continuously, which leads to serious decline in braking torque. This paper proposes a novel permanent magnet retarder (PMR) for vehicles, whose cooling system connects with engine cooling-water. A three-dimensional finite element model is developed to model the electromagnetic behavior of a permanent magnet retarder under a constant speed. The magnetic field and eddy current field in PMR are numerically solved by a finite element method. By accounting for the nonlinear permeability of the rotor and the weakened effect in the magnetic field that is generated by the eddy current magnetic field, the calculation accuracy of air-gap magnetic field is enhanced. Experiment shows that the temperature of the retarder is less than 150°C, and the braking torque keeps the hard characteristics curve. The calculated air-gap magnetic flux density is fairly good agreement with the measured one.

关键词： auxiliary brake permanent magnet retarder water-cooling finite element method

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三峡永久船闸高边坡工程的实践及验证

张超然

《中国工程科学》 2001年第3卷第5期页码 22-27

摘要：

三峡工程永久船闸高边坡工程系从左岸山体内开挖形成，两侧高边坡最大开挖深度达170 m，其下部为68 m高的直立墙，是三峡工程建设的重大技术难题。文章对三峡永久船闸高边坡设计原则和轮廓，施工程序，防渗及排水系统，高边坡加固支护措施，高边坡稳定分析以及永久船闸高边坡变形预测和高边坡监测资料验证等的研究结论和工程的重大科技成就做了介绍。

关键词：三峡永久船闸高边坡

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Impregnation of thermoplastic resin in jute fiber mat

LIU Xiaoye, DAI Gance

《化学科学与工程前沿（英文）》 2008年第2卷第2期页码 145-149 doi: 10.1007/s11705-008-0030-3

摘要： Impregnation rate of thermoplastic resin (polypropylene) in jute fiber mat and influence of relative factors on impregnation were studied, aiming to develop the continuous melt impregnation technique and to investigate the effect of impregnation rate and temperature on processing conditions and mechanical properties of natural fiber mat-reinforced thermoplastics. Influence of pressure on porosity of fiber mat and effect of melt viscosity on impregnation rate were also investigated. The modified capillary rheometer was used as apparatus and experimental data were analyzed based on the one-dimension Darcy’s law. Results showed that at a given pressure, the impregnation rate is inversely proportional to melt viscosity and jute fiber mat has higher porosity than glass fiber mat. The architecture, compressibility, permeability and fiber diameter of jute fiber mat were compared with those of glass fiber mat and their effects on impregnation were discussed further. It could be seen that the average diameter of jute fiber is much bigger; the porosity of jute fiber mat is significantly higher and inner bundle impregnation does not exist in jute fiber mat. Therefore, it is not difficult to understand why the impregnation rate in jute fiber mat is 3.5 times higher and permeability is 14 times greater. Kozeny constants of jute and glass fiber mats calculated based on the capillary model are 2950 and 442, respectively.

关键词： polypropylene diameter influence proportional impregnation

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Experimental study on flexural behavior of ECC/RC composite beams with U-shaped ECC permanent formwork

Zhi QIAO, Zuanfeng PAN, Weichen XUE, Shaoping MENG

《结构与土木工程前沿（英文）》 2019年第13卷第5期页码 1271-1287 doi: 10.1007/s11709-019-0556-0

摘要： To enhance the durability of a reinforced concrete structure, engineered cementitious composite (ECC), which exhibits high tensile ductility and good crack control ability, is considered a promising alternative to conventional concrete. However, broad application of ECC is hindered by its high cost. This paper presents a new means to address this issue by introducing a composite beam with a U-shaped ECC permanent formwork and infill concrete. The flexural performance of the ECC/RC composite beam has been investigated experimentally with eight specimens. According to the test results, the failure of a composite beam with a U-shaped ECC formwork is initiated by the crushing of compressive concrete rather than debonding, even if the surface between the ECC and the concrete is smooth as-finished. Under the same reinforcement configurations, ECC/RC composite beams exhibit increases in flexural performance in terms of ductility, load-carrying capacity, and damage tolerance compared with the counterpart ordinary RC beam. Furthermore, a theoretical model based on the strip method is proposed to predict the moment-curvature responses of ECC/RC composite beams, and a simplified method based on the equivalent rectangular stress distribution approach has also evolved. The theoretical results are found to be in good agreement with the test data.

关键词： engineered cementitious composite (ECC) durability ECC/RC composite beam permanent formwork flexural performance theoretical method