Role of aluminum on the physical and spectroscopic properties of chromium-doped strontium alumino borate glasses

2018 ◽  
Vol 32 (08) ◽  
pp. 1850095 ◽  
Author(s):  
Mohamed Raheem Ahmed ◽  
K. Chandra Sekhar ◽  
Abdul Hameed ◽  
M. Narasimha Chary ◽  
Md Shareefuddin
Keyword(s):  
Packing Density ◽  
Ion Pairs ◽  
Spectroscopic Properties ◽  
Band Frequency ◽  
Spectral Bands ◽  
Rhombic Symmetry ◽  
X Band ◽  
Prepared Glass ◽  
Racah Parameters ◽  
Quenching Method

The glass samples were prepared in accordance with the formula: (30-x)SrO–xAl2O3–69.8B2O3–0.2Cr2O3 (0 [Formula: see text]x [Formula: see text] 15 mol %) by melt quenching method. The absence of Bragg’s peaks confirmed the amorphous nature of the prepared glass samples. It was observed that the molar volume was increasing while the density is decreasing with increasing of Al2O3 content. Optical absorption study was performed to evaluate the optical bandgap, oxygen packing density, ionic packing density and Urbach energies. The Racah parameters (B and C) and D[Formula: see text]/B ratio have been calculated. Fourier transform infrared (FTIR) spectra recorded in the region from 400–1600 cm[Formula: see text] at room-temperature (RT) confirmed the formation of BO3, BO4 and AlO4 groups upon the addition of strontium oxide as modifier. The Raman spectra of all the glasses recorded over continuous spectral range 200–1600 cm[Formula: see text] exhibited different spectral bands. The EPR spectra recorded at 9.7 GHz (X-band frequency) have four resonance signals. The signal at g [Formula: see text] 5.33 is due to Cr[Formula: see text] ion sites of rhombic symmetry and signal at g [Formula: see text] 1.97 is due to contribution from Cr[Formula: see text] and Cr[Formula: see text] ion pairs.

scholarly journals Nanoparticles-decorated coal tar pitch-based carbon foam with enhanced electromagnetic radiation absorption capability

RSC Advances ◽  
2015 ◽  
Vol 5 (26) ◽  
pp. 20256-20264 ◽  
Author(s):  
Rajeev Kumar ◽  
Ashish Gupta ◽  
Sanjay R. Dhakate
Keyword(s):  
Electromagnetic Radiation ◽  
Coal Tar ◽  
Carbon Foam ◽  
Frequency Region ◽  
Radiation Absorption ◽  
Coal Tar Pitch ◽  
Band Frequency ◽  
X Band

Carbon foam decorated with magnetic and dielectric nanoparticles exhibited significantly improved EM radiation absorption in the X-band frequency region.

scholarly journals Investigation on the Dielectric Properties of Pulverized Oil Palm Frond and Pineapple Leaf Fiber for X-Band Microwave Absorber Application

2014 ◽  
Vol 893 ◽  
pp. 488-491 ◽  
Author(s):  
Elfarizanis Baharudin ◽  
Alyani Ismail ◽  
Adam Reda Hasan Alhawari ◽  
Edi Syams Zainudin ◽  
Dayang L.A. Majid ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Oil Palm ◽  
Microwave Absorber ◽  
Band Frequency ◽  
Pineapple Leaf Fiber ◽  
X Band ◽  
Oil Palm Frond ◽  
Palm Frond ◽  
Leaf Fiber

This paper presents the results on dielectric properties of pulverized material based on agricultural waste namely oil palm frond and pineapple leaf fiber for microwave absorber application in the X-band frequency range. The investigation is started by identifying the pulverized materials permittivities and loss tangents using coaxial probe technique, followed by density measurement comprising the determination of bulk and solid densities. Then, by using dielectric mixture model, the solid particle dielectric properties were determined. It is observed that the air properties give quite an effect on the permittivity and loss tangent of the pulverized materials. It is also found that the lower the material density the higher material dielectric constant will be. Furthermore, the results show that, both oil palm frond and pineapple leaf fiber are potential to be X-band absorber with average dielectric constant of 4.40 and 3.38 respectively. The loss tangents for both materials were observed to be more than 0.1 which mark them as lossy materials.

Design of a Fast-Sweeping C-X band Frequency Source Based on DDS and Frequency Multiplying Chain

2021 ◽  
Author(s):  
Yuwei Zhang ◽  
Awei Zhang ◽  
Chenkai He ◽  
Chunya Hou ◽  
Jinping Xu
Keyword(s):  
Band Frequency ◽  
X Band ◽  
Fast Sweeping ◽  
Frequency Source

Anion-cation interactions in a series of salts with substituted Hphen, Hbpy and H2bpy cations and [W(CN)8]4- anion: polymer with a “super-short” N-H···N hydrogen bridges containing exclusively anions and H+

2021 ◽  
Author(s):  
Anna Jurowska ◽  
Maciej Hodorowicz ◽  
Krzysztof Kruczała ◽  
Janusz Szklarzewicz
Keyword(s):  
Ion Pairs ◽  
Spectroscopic Properties

The 10 ion-pairs of [W(CN)8]4- with the substituted Hphen and Hnbpyn+ (where phen = 1,10-phenantroline, bpy = 2,2’-bipyridine, n = 1 or 2) were isolated and the spectroscopic properties of...

scholarly journals Complex Permittivity and Permeability Measurements and Numerical Simulation of carbonyl iron rubber in X-Band frequency

2014 ◽  
Vol 30 (2) ◽  
pp. 419-425 ◽  
Author(s):  
Adriano Luiz de Paula ◽  
Marcelo Bender Perotoni ◽  
Adriana Medeiros Gama ◽  
Luiz Alberto de Andrade
Keyword(s):  
Numerical Simulation ◽  
Complex Permittivity ◽  
Carbonyl Iron ◽  
Band Frequency ◽  
X Band ◽  
Permittivity And Permeability

scholarly journals Synthesis, Structural and Optical Investigations of (Pb, Bi)TiO3 Borosilicate Glasses

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chandkiram Gautam
Keyword(s):  
Spectroscopic Techniques ◽  
Borosilicate Glasses ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Spectral Bands ◽  
Prepared Glass ◽  
Infrared And Raman Spectroscopy ◽  
Uv Visible ◽  
Diffraction Patterns ◽  
Spectral Patterns

A new series of lead bismuth titanate borosilicate glasses with addition of one percent lanthanum oxide have been synthesized using melt-quench technique. X-ray diffraction patterns have been recorded to confirm the amorphous nature of the prepared glass samples. The synthesized glasses have been characterized by using various spectroscopic techniques such as UV-visible, infrared, and Raman spectroscopy. UV-visible measurements were recorded in the wavelength range from 200 to 1100 nm whereas IR and Raman spectroscopic measurements were recorded over a continuous wavenumber range from 400 to 5000 cm−1 and 1000 to 2000 cm−1 respectively. The different absorption peaks/bands were formed in IR spectral patterns. The spectral bands appear towards the lower wavenumber sides due to the Bi and Pb, content while the bands appear towards the higher wavenumber sides due to the formation of diborate and triborate network units.

scholarly journals Adaptive and High-Resolution Estimation of Specific Differential Phase for Polarimetric X-Band Weather Radars

2018 ◽  
Vol 35 (3) ◽  
pp. 555-573 ◽  
Author(s):  
Ricardo Reinoso-Rondinel ◽  
Christine Unal ◽  
Herman Russchenberg
Keyword(s):  
Standard Deviation ◽  
Spatial Variability ◽  
Heavy Rain ◽  
Storm Events ◽  
Band Frequency ◽  
Adaptive Approach ◽  
Range Resolution ◽  
Differential Phase ◽  
Weather Radars ◽  
X Band

ABSTRACTOne of the most beneficial polarimetric variables may be the specific differential phase KDP because of its independence from power attenuation and radar miscalibration. However, conventional KDP estimation requires a substantial amount of range smoothing as a result of the noisy characteristic of the measured differential phase ΨDP. In addition, the backscatter differential phase δhv component of ΨDP, significant at C- and X-band frequency, may lead to inaccurate KDP estimates. In this work, an adaptive approach is proposed to obtain accurate KDP estimates in rain from noisy ΨDP, whose δhv is of significance, at range resolution scales. This approach uses existing relations between polarimetric variables in rain to filter δhv from ΨDP while maintaining its spatial variability. In addition, the standard deviation of the proposed KDP estimator is mathematically formulated for quality control. The adaptive approach is assessed using four storm events, associated with light and heavy rain, observed by a polarimetric X-band weather radar in the Netherlands. It is shown that this approach is able to retain the spatial variability of the storms at scales of the range resolution. Moreover, the performance of the proposed approach is compared with two different methods. The results of this comparison show that the proposed approach outperforms the other two methods in terms of the correlation between KDP and reflectivity, and KDP standard deviation reduction.

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