外文資料翻譯--tphfe3o4磁性復合微球的制備以及寬頻微波吸收性質(zhì)的研究（英文）

1、The preparation and wide frequency microwave absorbing properties of tri-substituted-bisphthalonitrile/Fe3O4 magnetic hybrid microspheresShihua Dong, Mingzhen Xu, Junji Wei, Xulin Yang, Xiaobo Liu nResearch Branch of Fun

2、ctional Materials, Institute of Microelectronic the magnetic losswas enhanced obviously with the increasing amount of TPH. Additionally, the microwave absorptionproperties were detected, and the results demonstrated tha

3、t the strong reflection loss (RL) andmultimodal bands appeared in the wide frequency for the TPH/Fe3O4 magnetic hybrid microspheres.When the matching thickness was 5.0 mm, the effective RL values of ?31 dB, ?33 dB and ?3

4、7 dB wereobtained in the wide microwave frequency range from 2 GHz to 16 GHz by adjusting the content of TPH.The wide frequency microwave absorption properties, together with the regular sphere and excellentmagnetism, en

5、able TPH/Fe3O4 magnetic hybrid microspheres to be further applied in the areas offunctional materials.& 2013 Elsevier B.V. All rights reserved.1. IntroductionMagnetic hybrid microspheres are a new class of functional

6、 materials made of macromolecular organic matter and magnetite (Fe3O4), which possess the magnetic properties as well as proper- ties of organic matter. Its new functions shown by the combination of the organic and inorg

7、anic matters have attracted more and more attention. Widely researches and application have been implemented in the fields of biotechnology, chemical, military stealth material, environmental remediation and so on [1–4].

8、 In recent years, various methods have been successfully adopted in preparing Fe3O4 microspheres, such as core–shell processes, emulsion polymerization, miniemulsion polymeriza- tion, dispersion polymerization, suspensio

9、n polymerization, and cross-linking, etc. However, of all these methods, the structure and performance of the prepared magnetic hybrid microspheres showits pros and cons [5–9]. The process of tedious and time- consuming

10、preparation, broad size distribution and no-uniform magnetite fraction are now the new challenges to develop mag- netic composites. In addition, to obtain ideal absorbing materials with thin thickness and low density as

11、well as broad band microwave absorption, further researches are still essential. Recently, a facile one-step solvent-thermal crystallization route to prepare Fe3O4 microspheres has been developed in our lab [10,11]. The

12、results indicated that the Fe3O4 hybrid microspheres exhibited uniform particle size, stable magnetism and special strong microwave absorption properties, which efficiently solved the above problems and was widely applie

13、d in multi-functional magnetic materials. According to the literature, in the formation process of poly- mer/Fe3O4 magnetic hybrid microspheres, the microspheres prop- erties depend on the type and molecular structure of

14、 the organic species. Different kinds of the polymer combined with Fe3O4 will possess different structure and morphology, resulting in the distinguishable microwave absorption properties. As reported, the phthalocyanine-

15、based polymer/Fe3O4 magnetic hybrids canContents lists available at ScienceDirectjournal homepage: www.elsevier.com/locate/jmmmJournal of Magnetism and Magnetic Materials0304-8853/$ - see front matter & 2013 Elsevier

16、 B.V. All rights reserved.http://dx.doi.org/10.1016/j.jmmm.2013.08.038n Corresponding author. Tel./fax: þ86 028 83207326.E-mail address: Liuxb@uestc.edu.cn (X. Liu).Journal of Magnetism and Magnetic Materials 349 (2

17、014) 15–203.2. Magnetic propertiesThe hysteresis loops for TPH/Fe3O4 magnetic hybrid micro- spheres with various content of TPH are investigated at room temperature using a vibrating sample magnetometer (VSM), as shown i

18、n Fig. 4. The saturation magnetization and the coercivity values of the three samples are summarized in Table 1. The samples demonstrate better magnetic properties than those reported in literatures [17]: the saturation

19、magnetization values decrease along with the increasing amount of TPH, but still reach 58.16 emu g?1. The reason should be the existence of the organic matter in the Fe3O4 particles and the lower crystallization of magne

20、tite in the hybrid microspheres [17]. And S-3 has lower saturation magnetization than the other two samples (S-1, S-2), which is given rise to the biggest spin unordered degree and the increasing surface area of the magn

21、etic hybrid microspheres. It can be seen from the table that the coercivity increases along with the increasing amount of TPH. S-1 has the lowest coercivity, which can be attributed to the increased interparticle dipolar

22、 interaction from the decreased nanoparticle space distance for the single domain nanoparticles [14].3.3. Microwave electromagnetic propertiesIt is well known that dielectric constant and permeability are the intrinsic p

23、arameters of electromagnetic property for wave-absorbingmaterial. Both dielectric constant and permeability can be used in the plural under alternating magnetic [18]. In Fig. 5(a), the dielectric loss can be expressed as

24、 the ratio of the imaginary part (ε″) and the real part (ε′) of complex permittivity. The range of the dielectric loss is between 0.01 and 0.16. When the frequency is lower than 7 GHz, the dielectric loss curves of the s

25、amples are all small and similar. And the dielectric loss maximums of S-1, S-2 and S-3 appear at about 17 GHz,Fig. 2. FTIR spectra of S-1, S-2 and S-3.Fig. 1. SEM images of (a) pure Fe3O4, (b) S-1, (c) S-2 and (d) S-3.S.