Synthesis of various magnetic nanostructures and the microwave characterizations 4

... and the wall of the chamber The larger particles of the product get retained at the periphery of the chamber by centrifugal force and the smaller particles exit from the central port of the chamber ... ball milling and jet milling routes Fig 4. 11 The relationship of electromagnetic parameters and frequency in the range of 0.1~18 GHz:(a) and (b) ar...

Ngày tải lên: 08/09/2015, 19:44

... between these two parameters can be reduced when the permeability of the magnetic materials is high 1. 1.3 Snoek’s law For soft magnetic bulk materials, the product of the intrinsic permeability μi and ... μi at microwave frequency band There is another expression of Snoek’s law for planar materials, which is given as[8] 1/ 2 H (μi − 1) fr = γ4πMs ( ) H ea (1. 11) whe...

Ngày tải lên: 08/09/2015, 19:41

... ZF2 12 Zn0 .29 0Fe2.710O4 28 20 ZF3 12 Zn0.387Fe2.613O4 28 20 ZF3 _26 .5 Zn0.38Fe2.62O4 28 20 ZF3_13.4 7 .2 3.6 Zn0.38Fe2.62O4 28 20 ZF4 12 Zn0.468Fe2.532O4 28 20 ZF5 12 10 Zn0. 522 Fe2.478O4 28 20 ... 20 ZF6 12 12 Zn0. 524 Fe2.476O4 28 20 ZF7 12 14 Zn0. 527 Fe2.472O4 28 20 Note: The particle sizes of samples ZF0 to ZF7 are all around 100nm, while the particle s...

Ngày tải lên: 08/09/2015, 19:42

... ratio of Fe to Si about 5.4 Fig 3. 2(e1, e2, e3 and e4) are elemental mappings of C, O, Fe and Si, respectively, as labeled in the images The carbon shown in both of the EDS spectrum and the mapping ... surface of Fe particles is also evidenced by the EDS spectrum and elemental mapping The chemical analysis from the EDS spectrum in Fig 3. 2d 47 Chapter Synthes...

Ngày tải lên: 08/09/2015, 19:43

... monitoring the change in the magnetic moment 74 Chapter Size controllable synthesis of octahedral Fe3O4 nanoparticles and the microwave absorbing properties of the reaction solution during the synthesis ... nm Fig 5. 5 TEM images of the as-obtained Fe3O4 nanoparticles by reducing the concentration of oleic acid: A) 0. 35, B) 0.19, C) 0.10 and D-E) 0.07 M 5....

Ngày tải lên: 08/09/2015, 19:44

... in the developed synthesis method That’s why we use 12 mmol of Fe precursor as the starting materials for the study on synthesis of Zn ferrites 6. 2.3 Microwave absorption performance of as-synthesized ... chapter 6. 2 Experimental results 6. 2.1 Synthesis and characterizations on large size Zn-ferrite nanoparticles 6. 2.1.1 Effect of the molar ratio of Zn pr...

Ngày tải lên: 08/09/2015, 19:45

... (c) 70 nm -Fe2O3 tubes and (d) 98 nm -Fe2O3 rod The scale bars for all the images stand for 200 nm 7. 2.1.3 Size controllable synthesis of -Fe2O3 rods For the synthesis of -Fe2O3 rods, the ... comparing the SEM images of sample E (Fig 7. 7a) and D (Fig 7. 5d), we could find that the usage of 5%H2/95%Ar gas made a great improvement on the surface morpholog...

Ngày tải lên: 08/09/2015, 19:46

... frequency band Compared to the spherical Fe/Al alloys, the Fe/Al flakes show two advantages on the microwave absorption The one is that the thickness of the flakes is rather smaller than the skin ... future, the use of jet milling for the synthesis of submicron Fe/Al flakes may be tried on other materials (2) The thermal decomposition method is adopted to synthes...

Ngày tải lên: 08/09/2015, 19:46

... illustration of a VSM system Fig 2.6 The effects of (a) the isomer shift; (b) the quadrupole splitting and (c) the magnetic splitting on the nuclear energy levels of 57 Fe The Mössbauer absorptions and the ... parameters and frequency in the range of 0.1~18 GHz:(a) and (b) are the real and imaginary part of measured complex permittivity, respectively; (...

Ngày tải lên: 08/09/2015, 19:47

... IONP@PC and IONP@mC-600 Insets of C and F: SAED patterns of IONP@PC and IONP@mC-600 95 Figure 6-4: Particle size distributions of (A) IONP@PC and (B) IONP@mC-600 96 Figure 6-5 TEM images of IONP@mC-600 ... iron oxides and lithium was in the 1980s.[51] However, the nature of the reaction was not clear until J M Tarascon and his coworkers reported the conversion reaction...

Ngày tải lên: 10/09/2015, 09:30

... charge transfer from the S lone pairs to the CO p* antibonding orbital Altogether, these interactions add up to a total stabilization energy of more than kcal mol1, the largest of any of the complexes ... p*(CO) interaction, as many of the other structures Another minimum, 0.2 kcal mol1 higher than the first, adds another pair of charge transfers, both into the SS...

Ngày tải lên: 16/12/2012, 15:21

... The growth process of the different 1D TiO2 nanostructures was monitored by SEM and TEM Fig 2(a–c) shows the SEM images of the samples S1–S3, respectively, which reveal that the reaction of TiO2 ... PEG-300, 1D nanostructures of different morphologies such as nanorods, nanowires and nanotubes with different diameters and lengths were formed To understand the format...

Ngày tải lên: 20/03/2014, 13:08

... growth of ZnO, and results in the morphology of ZnO changing from “wire” to “flower”, “urchin” and “wire” with the addition of different amounts of ammonia Due to the different surface areas of the ... urchin-like ZnO; (b) sparse urchin-like ZnO; (c) orderly ZnO nanowire; (d) flower-like ZnO; and (e) disorderly ZnO nanowire Table Photovoltaic parameters of micro-...

Ngày tải lên: 06/05/2014, 13:23

... non-toxic, and mass production route for the synthesis of other functional oxide materials Experimental Preparation of NiO Nanostructures In a typical synthesis, appropriate amount of nickel powder was ... plays an essential role in the precursor material transformation because the vapor pressure is much higher and the state of water at elevated temperatures i...

Ngày tải lên: 22/06/2014, 01:20

... spectra of titania nanostructures S1, S2, and S3 The onset of absorption for the three samples is 382, 405, and 415 nm for S1, S2, and S3, respectively To determine the nature of the band gap, ... NaCl (5.0 M), and NH4Cl (5.0 M) were employed for the synthesis A typical microwave oven (Whirlpool, 1200W) operating at a frequency of 2,450 MHz was used for the synthe...

Ngày tải lên: 22/06/2014, 01:20