Morphology and Distribution of in Al-Fe Alloy under an Alternating Magnetic Field

2007 ◽  
Vol 546-549 ◽  
pp. 933-936
Author(s):  
Yi Han ◽  
Chun Yan Ban ◽  
Shi Jie Guo ◽  
Qi Xian Ba ◽  
Jian Zhong Cui
Keyword(s):  
Magnetic Field ◽  
Cooling Rate ◽  
Lorentz Force ◽  
Low Frequency ◽  
Alternating Magnetic Field ◽  
Al Matrix

The aim of this work is to study the effect of a low frequency alternating magnetic field on morphology and distribution of A3F2 in the Al-2.89 wt.% Fe alloy. At the cooling rate of 0.05 °C/s, only Al3Fe phase was observed in the iron-containing intermetallics. It was noteworthy that, compared with the conventional solidification, the primary Al3Fe phase was refined and accumulated towards the center of the sample by applying the alternating magnetic field. This phenomenon is considered as the result of the larger Lorentz force acting on the Al3Fe phase than the Al matrix.

Extremely low frequency alternating magnetic field–triggered and MRI–traced drug delivery by optimized magnetic zeolitic imidazolate framework-90 nanoparticles

Nanoscale ◽  
2016 ◽  
Vol 8 (6) ◽  
pp. 3259-3263 ◽  
Author(s):  
Jie Fang ◽  
Yong Yang ◽  
Wen Xiao ◽  
Bingwen Zheng ◽  
Yun-Bo Lv ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Drug Release ◽  
Low Frequency ◽  
Alternating Magnetic Field ◽  
Zeolitic Imidazolate Framework ◽  
Extremely Low Frequency

An extremely low frequency alternating magnetic field of 20 Hz was proved to be able to remarkably accelerate the drug release from optimized ZIF-90 nanospheres with incorporated Fe3O4 nanoparticles acting as actuator.

scholarly journals A Rapid Thermal Nanoimprint Apparatus through Induction Heating of Nickel Mold

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 334 ◽  
Author(s):  
Xinxin Fu ◽  
Qian Chen ◽  
Xinyu Chen ◽  
Liang Zhang ◽  
Aibin Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cooling Rate ◽  
Induction Heating ◽  
Nanoimprint Lithography ◽  
High Speed ◽  
Eddy Currents ◽  
Magnetic Hysteresis ◽  
Alternating Magnetic Field ◽  
Polymer Materials ◽  
Heating And Cooling

Thermal nanoimprint lithography is playing a vital role in fabricating micro/nanostructures on polymer materials by the advantages of low cost, high throughput, and high resolution. However, a typical thermal nanoimprint process usually takes tens of minutes due to the relatively low heating and cooling rate in the thermal imprint cycle. In this study, we developed an induction heating apparatus for the thermal imprint with a mold made of ferromagnetic material, nickel. By applying an external high-frequency alternating magnetic field, heat was generated by the eddy currents and magnetic hysteresis losses of the ferromagnetic nickel mold at high speed. Once the external alternating magnetic field was cut off, the system would cool down fast owe to the small thermal capacity of the nickel mold; thus, providing a high heating and cooling rate for the thermal nanoimprint process. In this paper, nanostructures were successfully replicated onto polymer sheets with the scale of 4-inch diameter within 5 min.

scholarly journals Heating ability of elongated magnetic nanoparticles

2021 ◽  
Vol 12 ◽  
pp. 1404-1412
Author(s):  
Elizaveta M Gubanova ◽  
Nikolai A Usov ◽  
Vladimir A Oleinikov
Keyword(s):  
Magnetic Field ◽  
Magnetite Nanoparticles ◽  
Volume Fraction ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Dipole Interaction ◽  
Alternating Magnetic Field ◽  
Particle Sizes ◽  
Order Of Magnitude ◽  
Elongated Nanoparticles

Low-frequency hysteresis loops and specific absorption rate (SAR) of various assemblies of elongated spheroidal magnetite nanoparticles have been calculated for a range of particle semiaxis ratios a/b = 1.0–3.0. The SAR of a dilute randomly oriented assembly of magnetite nanoparticles in an alternating magnetic field of moderate frequency, f = 300 kHz, and amplitude H0 = 100–200 Oe is shown to decrease significantly with an increase in the aspect ratio of nanoparticles. In addition, there is a narrowing and shift of the intervals of optimal particle diameters towards smaller particle sizes. However, the orientation of a dilute assembly of elongated nanoparticles in a magnetic field leads to an almost twofold increase in SAR at the same frequency and amplitude of the alternating magnetic field, the range of optimal particle diameters remaining unchanged. The effect of the magneto-dipole interaction on the SAR of a dilute assembly of oriented clusters of elongated magnetite nanoparticles has also been investigated depending on the volume fraction of nanoparticles in a cluster. It has been found that the SAR of the assembly of oriented clusters decreases by approximately an order of magnitude with an increase in the volume fraction of nanoparticles in a cluster in the range of 0.04–0.2.

scholarly journals Study on magnetorheological nano-polishing using low-frequency alternating magnetic field

2020 ◽  
Vol 12 (1) ◽  
pp. 168781401990072
Author(s):  
Jinzhong Wu ◽  
Shaohui Yin ◽  
Shengjie Yang ◽  
Yuanfan Guo
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
High Efficiency ◽  
Rotation Speed ◽  
Low Frequency ◽  
Alternating Magnetic Field ◽  
Improvement Rate ◽  
Current Frequency ◽  
Magnetorheological Polishing ◽  
K9 Glass

With the development of electronics and optical industry, the high-efficiency ultra-precision polishing technologies of flat and curved surfaces are in high demand. The traditional magnetorheological polishing technology, using flexible polishing head, has the disadvantages of low polishing efficiency and small processing area. In this study, a novel tray-type magnetorheological polishing process using low-frequency alternating magnetic field excitation was developed to improve the efficiency of magnetorheological polishing for large surfaces and to make polishing magnetorheological cluster generate a cyclical fluctuation up and down, and then improve the cross-cutting effects of abrasives. With the developed excitation system, a large bowl-shaped varying magnetic field was generated in the working area, and the effects of current frequency, working gap, trough rotation speed, and workpiece rotation speed on the improvement rate of surface roughness and material removal rate were systematically investigated. A series of experiments were conducted on K9 glass specimens to verify the polishing performance. Experimental results show that the surface roughness of K9 glass was improved from 567.08 to 9.63 nm in 120 min.

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