The low frequency motions of solvated Mn(ii) and Ni(ii) ions and their halide complexes

2014 ◽  
Vol 16 (45) ◽  
pp. 25101-25110 ◽  
Author(s):  
Vinay Sharma ◽  
Fabian Böhm ◽  
Gerhard Schwaab ◽  
Martina Havenith
Keyword(s):  
Low Frequency ◽  
Hydration Water ◽  
P Concentration ◽  
Halide Complexes ◽  
Absorption Measurements

Concentration dependent THz/FIR absorption measurements allow determination of individual solvated ion resonances and their influence on the hydration water spectrum.

Magnetic Permeability and Relaxation Frequency in High Frequency Magnetic Materials.

2001 ◽  
Vol 674 ◽  
Author(s):  
M.I. Rosales ◽  
H. Montiel ◽  
R. Valenzuela
Keyword(s):  
High Frequency ◽  
Domain Walls ◽  
Magnetocrystalline Anisotropy ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Anisotropy Constant ◽  
Relaxation Frequency ◽  
Resonance Relaxation ◽  
Frequency Behavior

ABSTRACTAn investigation of the frequency behavior of polycrystalline ferrites is presented. It is shown that the low frequency dispersion (f < 10 MHz) of permeability is associated with the bulging of pinned domain walls, and has a mixed resonance-relaxation character, closer to the latter. It is also shown that there is a linear relationship between the magnetocrystalline anisotropy constant, K1, and the relaxation frequency. The slope of this correlation depends on the grain size. Such a relationship could allow the determination of this basic parameter from polycrystalline samples.

Fast Determination of Phosphorus Concentration in Phosphogypsum Waste Using Calibration-Free LIBS in Air and Helium

2021 ◽  
Author(s):  
Khaled Elsayed ◽  
Walid Tawfik ◽  
Ashraf E M Khater ◽  
Tarek S Kayed ◽  
Mohamed Fikry
Keyword(s):  
Complete Analysis ◽  
Phosphorus Concentration ◽  
Stark Broadening ◽  
Breakdown Spectroscopy ◽  
P Concentration ◽  
Characteristic Lines ◽  
Laser Induced Breakdown ◽  
Novel Method ◽  
Calibration Free

Abstract This work represents a novel method to determine phosphorus (P) concentration in phosphogypsum (PG) waste samples using calibration-free laser-induced breakdown spectroscopy (LIBS). A 50 mJ Q-switched Nd: YAG laser has generated the PG LIBS spectrum. Spectroscopic analysis of plasma evolution has been characterized by electron density Ne and electron temperature Te using the emission intensity and stark broadening for P I characteristic lines 213.61, 214.91, and 215.40 nm under non-purged (air) and purged (helium) conditions. It was found that both Te and Ne have significant changes linearly with P concentrations 4195, 5288, 6293, and 6905 ppm. The values of plasma Te and Ne increased from about 6900 to 10000 K and 1.1×1017 to 3.4×1017 cm− 3, respectively, for the non-purged PG. On the other hand, Te and Ne ranged from 8200 to 11000 K and 1.4×1017 to 3.5×1017 cm− 3, respectively, for the PG purged with helium. It is concluded that Te and Ne values represent a fingerprint plasma characterization for a given P concentration in PG samples, which can be used to identify P concentration without a PG's complete analysis. These results demonstrate a new achievement in the field of spectrochemical analysis of environmental applications.

Methyl Isocyanide: The Low-Frequency Bands ν8 and ν7, and a Determination of the Rotational Constant A0

1995 ◽  
Vol 173 (2) ◽  
pp. 423-430 ◽  
Author(s):  
J. Pliva ◽  
L.D. Le ◽  
J.W.C. Johns ◽  
Z. Lu ◽  
R.A. Bernheim
Keyword(s):  
Low Frequency ◽  
Rotational Constant ◽  
Frequency Bands ◽  
Methyl Isocyanide

Determination of Electric and Magnetic Properties of Commercial LTCC Soft Ferrite Material

2011 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nelu Blaž ◽  
Andrea Marić ◽  
Goran Radosavljević ◽  
Nebojša Mitrović ◽  
Ibrahim Atassi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Frequency Range ◽  
Dispersion Parameters ◽  
Simple Method ◽  
Component Design ◽  
Microwave Engineering ◽  
Characterization Procedure

This paper offers an effective, accurate, and simple method for permittivity and permeability determination of an LTCC (low temperature cofired ceramic) ferrite sample. The presented research can be of importance in the fields of ferrite component design and application, as well as for RF and microwave engineering. The characterization sample is a stack of LTCC tapes forming a toroid. Commercially available ferrite tape ESL 40012 was used and standard LTCC processing was applied for the sample fabrication. For the first time, the electrical properties of a ferrite toroid sample of ESL 40012 LTCC ferrite tape is presented at various frequencies. The electrical properties of LTCC ferrite materials, permittivity and specific resistivity, are shown in a frequency range from 10 kHz to 1 MHz using the capacitive method. The hysteresis properties of this material are also determined. B-H hysteresis loops were measured applying a maximum excitation of 2 kA/m and frequencies of 50 Hz, 500 Hz, and 1000 Hz. Permeability is determined in the frequency range from 10 kHz to 1 GHz and a characterization procedure is divided in two segments, for low and high frequencies. Low frequency measurements (from 10 kHz to 1 MHz) are performed using LCZ meter and discrete turns of wire, while a short coaxial sample holder and vector network analyzer were used for the higher frequency range (from 300 kHz to 1 GHz). In addition, another important factor required for the practical design of devices is presented, the temperature variation of the permeability dispersion parameters.

scholarly journals Polymorphisms in Brucella Carbonic anhydrase II mediate CO2 dependence and fitness in vivo

2019 ◽  
Author(s):  
JM García-Lobo ◽  
Y Ortiz ◽  
C González-Riancho ◽  
A Seoane ◽  
B Arellano-Reynoso ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Primary Cultures ◽  
Low Frequency ◽  
Carbonic Anhydrase Ii ◽  
Carbonic Anhydrases ◽  
Significant Difference ◽  
Dependent Strain

AbstractSome Brucella isolates are known to require an increased concentration of CO2 for growth, especially in the case of primary cultures obtained directly from infected animals. Moreover, the different Brucella species and biovars show a characteristic pattern of CO2 requirement, and this trait has been included among the routine typing tests used for species and biovar differentiation. By comparing the differences in gene content among different CO2-dependent and CO2-independent Brucella strains we have confirmed that carbonic anhydrase II (CA II), is the enzyme responsible for this phenotype in all the Brucella strains tested. Brucella species contain two carbonic anhydrases of the β family, CA I and CA II; genetic polymorphisms exist for both of them in different isolates, but only those putatively affecting the activity of CA II correlate with the CO2 requirement of the corresponding isolate. Analysis of these polymorphisms does not allow the determination of CA I functionality, while the polymorphisms in CA II consist of small deletions that cause a frameshift that changes the C-terminus of the protein, probably affecting its dimerization status, essential for the activity.CO2-independent mutants arise easily in vitro, although with a low frequency ranging from 10−6 to 10−10 depending on the strain. These mutants carry compensatory mutations that produce a full length CA II. At the same time, no change was observed in the sequence coding for CA I. A competitive index assay designed to evaluate the fitness of a CO2-dependent strain compared to its corresponding CO2-independent strain revealed that while there is no significant difference when the bacteria are grown in culture plates, growth in vivo in a mouse model of infection provides a significant advantage to the CO2-dependent strain. This could explain why some Brucella isolates are CO2-dependent in primary isolation. The polymorphism described here also allows the in silico determination of the CO2 requirement status of any Brucella strain.

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