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您的检索式：作者名="QINHongwei"
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| 1 | Effects of quenching speed and Joule heating on the magnetic properties of Nd_9Fe_(86)B_5 ribbons显示文摘The influences of quenching speed and current annealing on the magnetic properties of Nd9Fe86B5 ribbons were investigated. There is an optimum quenching speed (v ≈ 15 m/s) for preparing hard magnetic ribbons, where the remanence of 1.22 T, the intrinsic coercivity of 521 kA?m?1 and the energy products of 150 kJ?m?3 are obtained. After annealing ribbons prepared with v = 20 m/s at a dc current of 0.85 A, the remanence reaches a quite large value of 1.47 T, which attributes to the strong exchange coupling interactions between the fine grains of Nd2Fe14B and α-Fe. | ANKang HUJifan WANGDongling QINHongwei SUNGuangfei CHENJufang YUXiaojun LIBo | 2005 | Rare Metals2005，24，2： | 1 |
| 2 | Amorphization and magnetic properties of Fe_(62)Nb_(38) mechanically alloyed powders显示文摘The amorphization and magnetic properties of Fe62Nb38 mechanically alloyed powders were investigated. In the initial mechanical alloying processes, the lattice structure of pure Fe is destroyed due to the cold-welding and fracturing, accompanying the reduction of ferromagnetic properties. The Ms value of Fe62Nb38 powders with ball-milling time t = 6 h is only 48.1 A.m2/kg. With prolongating of mechanical alloying processes, a solid state amorphization reaction (SSAR) takes place and the Fe-Nb ferromagnetic amorphous phase is formed. With the milling time increasing from 6 to 18 h, the satura tion magnetization of Fe62NB38 powders increases with enhancement of the proportion of ferromagnetic amorphous phase in from dilute model. However, the Curie temperature of the Fe62Nb38 amorphous phase is only 206°C, which is much smaller than that of the pure Fe. This implies that the exchange interaction between Fe atoms in amorphous alloyed Fe62Nb38 becomes weak due to the Nb dilution. Investigation shows that the variation of magnetic properties of milled powders is one of important tools for describing the amorphization by mechanical alloying. | QINHongwei HUJifan YANGFuming | 2004 | Rare Metals2004，23，3： | 0 |
| 3 | Giant magnetoimpedance effect in Fe-Zr-Nb-Cu-B nanocrystalline ribbons显示文摘The giant magnetoimpedance effect of the nanocrystalline ribbon Fe84Zr2.08Nb1.92Cu1B11 (atom fraction in %) was investigated. There is an optimum annealing temperature (TA≈ 998 K) for obtaining the largest GMI (giant magneto impedance) effect in the ribbon Fes4Zr2.08Nb1.92Cu1B 11. The ribbon with longer ribbon length has stronger GMI effect, which may be connected with the demagnetization effect of samples. The frequencyfmax, where the maximum magnetoimpedance GMI(Z)max = [(Z(H) - Z(0))/Z(0)]max occurs, is near the intersecting frequency fi of the curves of GMI(R), GMI(X), and GMI(Z) versus frequency. The magnetoreactance GMI(X) decreases monotonically with increasing frequency, which may be due to the decrease of permeability. In contrast, with the AC (alternating current) frequency increasing, the magnetore sistance GMI(R) increases at first, undergoes a peak, and under then drops. The increase of the magnetoresistance may result from the enhancement of the skin effect with frequency. The maximum magnetoimpedance value GMI(Z)max under H = 7.2 kA/m is about -56.18% at f= 0.3 MHz for the nanocrystalline ribbon Fe84Zr2.08Nb1.92Cu1B11 with the annealing temperature TA= 998 K and the ribbon length L = 6 cm. | ANKang HUJifan QINHongwei HANTao WANGYizhong YUXiaojun LIBo | 2004 | Rare Metals2004，23，3： | 0 |
| 4 | Giant magneto-impedance and permeability in Fe_(89)Zr_6Hf_1B_4 ribbons显示文摘The giant magneto-impedance (GMI) effect associated with the variation of transverse permeability for the rib-bons Fe89Zr6Hf1B4 with different annealing temperatures TA = 793, 823, 893, 923, 993, and 1033 K was investigated. There is an optimum annealing temperature TA ≈ 993 K for obtaining the largest GMI effect for the ribbons Fe89Zr6Hf1B4. The magneto-impedance GMI (Z) = (Z(H) ? Z(0))/Z(0) for the ribbon with TA = 993 K can reach ?55.09% at a frequency f = 900 kHz under H = 7162 A/m. The relative changes of the real part of transverse permeability ?μ′/μ′0 = (μ′(H)? μ′(0))/μ′(0) under H = 7162 A?m?1 at f = 1 MHz are ?78.83%, ?89.98% and ?94.77 % for Fe89Zr6Hf1B4 ribbons with TA = 823, 893, and 993 K, respectively. The strong GMI effect is accompanied by the large change of transverse permeability. A large magnetoreactance GMI(X) = (X (H) ? X (0))/X (0) of ?81.09% can be obtained at f = 100 kHz under H = 7162 A/m for the ribbon with TA = 993 K. Meanwhile, this present result gave an experimental support to the previous concept / assumption that the positive peak in the field dependence of magneto-impedance is connected to the peak of transverse permeability with varying fields. | YUXiaojun HUJifan LIBo QINHongwei WANGDonglin LIWei | 2005 | Rare Metals2005，24，2： | 0 |
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