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Zou Z.Y.,Donghua University | de Zhu Y.,Ningbo Yunsheng Co. | Hua Z.H.,Donghua University | Wang Y.,Donghua University | Cheng D.L.,Donghua University
Textile Research Journal | Year: 2010

A dynamic model of the infinitesimal element of the flexible fiber is proposed, which describes the flexible fiber trajectory in the condensing zone of compact spinning with lattice apron. Based on the flow simulation in the condensing zone, the flexible fiber trajectory is simulated by a specially designed Matlab program routine. The trajectories of the fibers of different initial positions can explain the pneumatic condensing mechanism in the condensing zone. The results show that fiber trajectories of different initial positions in the condensing zone gradually converge, and the condensing process of the fiber bundle is divided into three parts: the rapid condensing region, the adjustive condensing region and the steady condensing region. The fibers of different initial positions will be interlaced for position change in yarn cross-section, caused by the airflow in the condensing zone. Moreover, fibers will gradually close the surface of the lattice apron when fibers are delivered from the rapid condensing region to the steady condensing region. © The Author(s), 2010.

Guo J.,Xinjiang University | Guo J.,Ningbo Institute of Materials Technology and Engineering | Dong Y.,Ningbo Institute of Materials Technology and Engineering | Man Q.,Ningbo Institute of Materials Technology and Engineering | And 5 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2016

Fe-based amorphous magnetic alloy powders with a composition of (Fe0.76Si0.09B0.1P0.05)99Nb1 were first prepared by water atomization, and then amorphous magnetic powder cores were produced from a mixture of the amorphous alloy powders with diameters of below 75 μm and different volume of insulation and bonding materials by mold compacting with a compact pressure of 2200 MPa at room temperature. The amorphous magnetic cores exhibit superior DC-bias properties and excellent soft magnetic properties after appropriate heating treatment. The DC-bias properties of the present amorphous magnetic cores just decrease 15% as the external field increases to 100 Oe. Meanwhile, it also exhibits a high permeability of 56 at 1 MHz and a low core loss of 451 W/kg at Bm=0.1 T and f=100 kHz. The present Fe-based amorphous magnetic powder cores with superior DC-bias properties are a potential candidate for a variety of industrial applications. © 2015 Elsevier B.V. All rights reserved.

Dong Y.,Ningbo Institute of Materials Technology and Engineering | Man Q.,Ningbo Institute of Materials Technology and Engineering | Zhang J.,Ningbo Institute of Materials Technology and Engineering | Zhang J.,Xinjiang University | And 4 more authors.
IEEE Transactions on Magnetics | Year: 2015

Glassy Fe77P7B13Nb2Cr1 alloy powders with the particle size below 100μm were synthesized by water atomization using industrial raw materials. The glassy powders were consolidated into bulk forms through sintering them at different temperatures by hot pressing. The resulting glassy core sintered at 771 K, which between the supercooled liquid region, has a high relative density of 91% compared with the master alloy. It also exhibits good soft magnetic properties, i.e., high saturation magnetic flux density Bs of 1.13 T, low coercive force Hc of 50 A/m, relatively high effective permeability μe of 1200 at 1 kHz under a field of 1 A/m, low core loss P of 1393 mW/cm3 at 50 kHz under the maximum magnetic flux density of 0.1 T. The synthesis of Fe-based glassy cores with good soft magnetic properties is encouraging for future applications as functional materials. © 2015 IEEE.

Ningbo Yunsheng Co., High-Tech, Ningbo Yunsheng Special Metal Material Co. and Baotou Yunsheng Strong Magnetic Material Co. | Date: 2014-11-14

A method for preparing a NdFeB-based sintered magnet. The method includes: 1) providing a master alloy and an auxiliary alloy, the master alloy being a NdFeB alloy ingot or cast strip, the auxiliary alloy being a heavy rare earth alloy; 2) breaking up the master alloy using a hydrogen decrepitation process to yield a crude powder, conducting hydrogen absorption treatment on the auxiliary alloy and breaking up the hydrogenated auxiliary alloy to yield hydride particles; 3) uniformly mixing and stirring the crude powder of the master alloy and the hydride particles of the auxiliary alloy to yield a mixture; 4) milling the mixture obtained in step 3) to yield powders; 5) uniformly stirring the powders obtained in step 4) and conducting orientation forming treatment on the powders, to yield a raw body of a NdFeB based magnet; and 6) sintering the raw body of the NdFeB based magnet.

Zhu Y.-D.,Ningbo Yunsheng Co. | Wu J.-M.,Ningbo Yunsheng Co.
Journal of Donghua University (English Edition) | Year: 2010

In compact spinning with pneumatic groove, the computational fluid dynamic model, computed with parallel technologies & Fluent 6.3, is developed to simulate the flow field in condensing zone with 3D computational fluid dynamic (CFD) technology. Flowing state, distribution rules of static pressure, and velocity in condensing zone are characterized and analyzed. The results show that the fiber bundle in compact spinning with pneumatic groove is compacted by airflow and the shape of the pneumatic groove, and the static pressure in condensing zone is negative, as well as the velocity of airflow in condensing zone is not zero. The fluctuation frequencies of the static pressure and velocity near the bottom of the pneumatic groove are relatively higher, and the number of the fluctuation is equal to that of the round holes in condensing zone. Copyright © 2010 Editorial Department of Journal of Donghua University.

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