Microwave Absorption Characteristic of ZnNd(x)Fe(2-x)O4 System

2020 ◽  
Vol 855 ◽  
pp. 280-285
Author(s):  
Mashadi ◽  
Andhika Ajiesastra ◽  
Yunasfi
Keyword(s):  
Microwave Absorption ◽  
Morphological Observation ◽  
Absorption Characteristic ◽  
X Ray Diffraction ◽  
High Frequencies ◽  
Detection Systems ◽  
Uniform Particles ◽  
X Band ◽  
Ion Substitution ◽  
Diffraction Patterns

The ZnNd(x)Fe(2-x)O4 (x = 0.0; 0.010; 0.020 and 0,030) systems were synthesized by solid reaction method from a mixture of ZnO2, Fe2O3 and Nd2O3 powders according to their mole ratio using mechanical milling techniques. In this mixture was added ethanol of 25 ml and then milled for 5 hours, after that sintered at a temperature of 1000 °C for 5 hours. X-ray diffraction patterns showed that the Nd3+ ion substitution in ZnFe2O4 with the concentration of x = 0.0 to 0.02 did not result in changes in ZnFe2O4 phase with cubic structure (space group of Fd-3m). However, the composition of x = 0.030 formed multiphases ZnFe2O4 and NdFeO3 phases. The morphological observation using Scanning Electron Microscope (SEM) showed spherical and uniform particles. Whereas the microwave absorption capability of the sample ZnNd(x)Fe(2-x)O4 system increased with the increasing concentration of x from 91.20% up to 97.80% with the highest absorption is found at a frequency of 10.24 GHz. The dielectric loss of this study is very small around 0.005 up to 0.05. It is hoped that the compound ZnNd0.02Fe1,98O4 can be applied to microwave absorbing agents at high frequencies (X-band range) in antiradar detection systems.

MICROWAVE ABSORPTION BEHAVIOR OF MESOPOROUS TRANSITION METAL OXIDE TEMPLATED FROM SBA-15 AND KIT-6

2014 ◽  
Vol 28 (10) ◽  
pp. 1450037 ◽  
Author(s):  
HONGJING WU ◽  
LIUDING WANG ◽  
YIMING WANG
Keyword(s):  
Electron Microscope ◽  
Microwave Absorption ◽  
Absorption Characteristic ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Hard Template ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Transmission Electron

In this paper, we have synthesized meso-oxides (i.e., Co 3 O 4 and NiO ) by using mesoporous silica as hard template. The microstructures and chemical compositions of the corresponding meso-oxides were characterized by the Transmission electron microscope-selected area electron diffusion (TEM-SAED), X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), respectively. And, their electromagnetic and microwave absorption properties were investigated in the frequency range of 2–18 GHz. The results indicate that meso-oxide templated from KIT-6 (i.e., meso-K– Co / Ni ) exhibit a dual absorption characteristic compared with those using SBA-15 as hard template. This phenomenon suggests that meso-oxides templated from SBA-15 and KIT-6 can exhibit different microwave absorption behaviors due to their respective microstructures.

Flash X-Ray Diffraction Systems

1972 ◽  
Vol 16 ◽  
pp. 229-241 ◽  
Author(s):  
Jonathan A. Dantzig ◽  
Robert E. Green
Keyword(s):  
Fiber Optic ◽  
Single Channel ◽  
Image Intensifier ◽  
Electron Beam Current ◽  
X Ray Diffraction ◽  
Output Window ◽  
Visible Image ◽  
X Ray ◽  
Detection Systems ◽  
Diffraction Patterns

AbstractIn order to develop an optimum system for flash x-ray diffraction, consideration must be given to both optimum x-ray generation and optimum x-ray detection in the correct wavelength regime suitable for diffraction. Historically, most workers have concentrated their efforts in either the generation area or detection area, but not both. As early as 1942, experimental recording of Laue diffraction patterns was reported using a pulsed x-ray generator and exposure times of milliseconds. Recently, successful x-ray diffraction experiments have been reported with exposure times less than 100 nanoseconds.The purpose of the present paper is to trace the development of generation and detection systems for flash x-ray diffraction and to summarize the present state-of-the-art for such systems. A comparative evaluation is presented for flash x-ray diffraction systems using generators which rely on increased electron beam current and those which rely on higher potential difference. Comparison is also made between detection systems incorporating film recording, scintillators fiber-optically coupled to photomultiplier tubes, and image-intensifier systems both lens and fiber-optically coupled to fluorescent screens.A detailed description of the most rapid flash x-ray diffraction system developed to date is given. This system uses a Field Emission Fexitron single channel 300 kilovolt pulsed x-ray generator incorporating an x-ray tube with a beryllium output window. A fluorescent screen converts the x-ray diffraction image into a visible one and this visible image is focused on the first stage photocathode of an image intensifier tube either by direct fiber-optic coupling or by using a coupling lens. The image intensifier tube used is a cascaded three-stage electrostatic focus type with fiber-optic input and output faceplates and inter-stage couplers. Using this system Laue transmission diffraction patterns of single crystals and powder patterns of polycrystalline aggregates have been obtained with exposure times of 30 nanoseconds.

Double Layer Microwave Absorption Characteristics of Barium Hexaferrite/Silica Composite for X-Band Frequencies

2018 ◽  
Vol 929 ◽  
pp. 109-115 ◽  
Author(s):  
Erfan Handoko ◽  
Iwan Sugihartono ◽  
Mangasi Alion Marpaung ◽  
Maulana Randa ◽  
Mudrik Alaydrus ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Double Layer ◽  
Reflection Loss ◽  
Barium Hexaferrite ◽  
Complex Permeability ◽  
X Ray Diffraction ◽  
Silica Composite ◽  
X Band ◽  
Line Theory ◽  
Absorption Characteristics

Microwave absorption characteristics of double layer of barium hexaferrite attached on the silica to from a composite on the basis of wave propagation theory have been investigated. Barium hexaferrite, BaFe12O19, was synthesized through ceramic method from stoichiometric mixtures of BaCO3 and Fe2O3 as precursors. The mixture was pelletized under the pressure of 10 MPa and sintered at 1100 °C for 5 hours. Silica in the forms of powder was purified by using HCl. The crystal structure of the samples was characterized using X-ray diffraction (XRD), microstructure was examined using scanning electron microscope (SEM), hysteresis curves recorded by PERMAGRAPH techniques, whereas the microwave absorbing properties for X-band was recorded using a vector network analyzer (VNA). Relative complex permeability and permittivity, and reflection loss values were calculated at given thickness according to transmittance line theory within the range 8.2–12.4 GHz. Based on this study, the layer dimension and frequency that results in low reflection loss can be estimated from the material properties of the barium hexaferrite/silica composite material.

EFFECT OF Ni ON THE ELECTRICAL AND MICROSTRUCTURAL PROPERTIES OF NANOCRYSTALLITES Fe2O3/TiO2 SYSTEM

2006 ◽  
Vol 13 (04) ◽  
pp. 479-484 ◽  
Author(s):  
MAGED S. SOBHY
Keyword(s):  
Electrical Resistivity ◽  
Spinel Ferrite ◽  
Average Crystalline Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Value ◽  
Semiconductor Behavior ◽  
Ion Substitution ◽  
Diffraction Patterns ◽  
Increasing Temperature

Nominal compositions of Ni x Ti 1-x Fe 2 O 5-δ (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared by a solid state reaction using stoichiometric amounts of Fe 2 O 3/ TiO 2 system and NiO as a dopant. The effects of small substitution of Ni ions on the electrical and structural properties were studied for the above system. The X-ray diffraction patterns revealed that the ferroelectric phase of iron titanate and the spinel ferrite phase of Ni -ferrite having a single phase at x = 0 and 1, respectively. The substitution of Ni ions increases the average value of lattice constant aav. Solid–solid interaction took place between the ternary oxides at 1200°C for 4 h yielding a new phase of NiTiO 3. The presence of the three phases was confirmed by X-ray diffraction technique. The resultant compositions have nanocrystallites with average crystalline size "D av " in the range 100–300 nm. The DC electrical resistivity ρ, Curie temperature TC and activation energies for electric conduction around TC region increase as Ni ion substitution increases. The ferrite samples have a semiconductor behavior where electrical resistivity ρ decreases on increasing temperature. The activation energy for electrical conduction was affected by both the ratio "ferroelectric/ferrite" and the position of the Curie temperatures in the compositions depending on the ( Ni , Ti ) to Fe ratio.

Complex Permittivity, Permeability and Microwave Absorption Studies of Double Layer Magnetic Absorbers Based on BaFe12O19 and BaFe10CoZnO19

2019 ◽  
Vol 966 ◽  
pp. 302-307
Author(s):  
Erfan Handoko ◽  
Iwan Sugihartono ◽  
Mangasi Alion Marpaung ◽  
Ucu Cahyana ◽  
Sovian Aritonang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Double Layer ◽  
Complex Permittivity ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Matching Layer ◽  
X Band ◽  
Absorption Studies

Microwave absorption properties of double layer magnetic absorbers based on BaFe12O19 (BFO) and BaFe10CoZnO19 (BFCZO) have been investigated in X-band (8.2–12.4 GHz) frequencies. The BFO and BFCZO were prepared by using a solid state reaction process. The crystalline structures were investigated by X-ray diffraction (XRD), The complex permittivity and permeability are determined using Vector Network Analyzer (VNA) in a range from 8.2 GHz to 12.4 GHz. The double layer magnetic absorbers, composed of the BFO as matching layer and the BFCZO as absorption layer, with a total thickness of 5 mm, showed an effective reflection loss (RL) an effective absorbing bandwidth below –5 dB.

scholarly journals MAGNETIC AND MICROWAVE ABSORPTION PROPERTIES OF NEODYMIUM DOPED NICKEL FERRITE USING MILLING TECHNIQUE

2019 ◽  
Vol 81 (4) ◽  
Author(s):  
Yunasfi Yunasfi ◽  
Mashadi Mashadi ◽  
Ade Mulyawan
Keyword(s):  
Nickel Ferrite ◽  
Magnetic Measurement ◽  
Spinel Ferrite ◽  
Solid State Reaction Method ◽  
High Energy ◽  
Morphological Observation ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Diffraction Patterns ◽  
Compound Materials

Nickel ferrite doped by neodymium in the form of (Ni(1-x)NdxFe2O4) with (x =  0.0 ; 0.2 and 0.4) have been synthesized using solid state reaction method with milling technique from NiO, Nd2O3 and Fe2O3 powder. The mixture of those compound materials was milled using High Energy Milling (HEM) machine for 10 hours and then sintered at 1000 °C for 5 h. X-ray diffraction patterns showed that a single phase of spinel ferrite has been formed in all of the compositions. The result of morphological observation using Scanning Electron Microscope (SEM) exhibited a homogeneous structure has been formed with particle size about 200 nm. The magnetic measurement using vibrating sample magnetometer (VSM) showed that the sample exhibited a ferromagnetic behavior, where the Ms value decrease (around of 58.4 to 39.40 emu/g) and value of Hc increased (around of 116-170 Oe) along with the addition of the Nd3+ ion (x values) content. While the ability of microwaves absorption measured by using Vector Network Analyzer (VNA) indicates that the maximum value of Reflection Loss (RL) obtained at the composition of x = 0.4 up to -29 dB at a frequency of 10.81 GHz. It means the Ni0,6Nd0,4Fe2O4 sample can absorb microwave up to ~ 96.5% at a frequency of 10.81 GHz.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Quantitative Electron Microscope with imaging plate

1994 ◽  
Vol 52 ◽  
pp. 408-409
Author(s):  
D. Shindo
Keyword(s):  
Electron Microscope ◽  
Dynamic Range ◽  
Processing System ◽  
Digital Data ◽  
Imaging Plate ◽  
Crystal Thickness ◽  
X Ray Diffraction ◽  
Resolution Electron ◽  
Electron Intensity ◽  
Diffraction Patterns

Imaging plate has good properties, i.e., a wide dynamic range and good linearity for the electron intensity. Thus the digital data (2048x1536 pixels, 4096 gray levels in log scale) obtained with the imaging plate can be used for quantification in electron microscopy. By using the image processing system (PIXsysTEM) combined with a main frame (ACOS3900), quantitative analysis of electron diffraction patterns and high-resolution electron microscope (HREM) images has been successfully carried out.In the analysis of HREM images observed with the imaging plate, quantitative comparison between observed intensity and calculated intensity can be carried out by taking into account the experimental parameters such as crystal thickness and defocus value. An example of HREM images of quenched Tl2Ba2Cu1Oy (Tc = 70K) observed with the imaging plate is shown in Figs. 1(b) - (d) comparing with a structure model proposed by x-ray diffraction study of Fig. 1 (a). The image was observed with a JEM-4000EX electron microscope (Cs =1.0 mm).

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