THE STRUCTURAL STUDY OF Fe2O3–TeO2–B2O3–SrF2 GLASSES BY  EPR AND IR SPECTROSCOPIES

The local structure of Fe2O3–TeO2–B2O3–SrF2 glasses was studied by recording the EPR and IR absorption spectra. Structural changes and increasing glass stability were evidenced with the addition of Fe2O3 in the sample. The distribution of isolated paramagnetic ions in sites of strongly distorted octahedral symmetry was detected at low concentration (up to 3 mol% Fe2O3) by means of EPR measurements. For x>3 mol% Fe2O3, the clustered iron ions become progressively preponderent in the system. Mixed valence states of iron ions involved in dipole–dipole and superexchange type interactions were also evidenced. The IR spectra analysis revealed the BO3, BO4 and B2O6 units in the structure of tellurite investigated glasses. Among these structural units, those containing the threefold boron atoms are predominant.

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STRUCTURAL INVESTIGATIONS OF CuO–B2O3–Bi2O3 GLASSES BY MEANS OF EPR AND FT-IR SPECTROSCOPIES

Modern Physics Letters B ◽

10.1142/s0217984904007414 ◽

2004 ◽

Vol 18 (16) ◽

pp. 803-810 ◽

Cited By ~ 1

Author(s):

I. ARDELEAN ◽

SIMONA CORA ◽

RALUCA CICEO-LUCACEL

Keyword(s):

Local Structure ◽

Copper Content ◽

Copper Ions ◽

Glass Structure ◽

Mixed Valence ◽

Structural Investigations ◽

Valence States ◽

Distorted Octahedral ◽

Ft Ir ◽

Ft Ir Spectroscopy

EPR and FT-IR spectroscopy have been used to investigate the B 2 O 3– Bi 2 O 3 glass matrix containing CuO in order to obtain more information about the local structure of these glasses. The EPR absorption spectra revealed the presence in the glass structure of the Cu 2+ ions in axially distorted octahedral environments. No superexchange interaction of Cu 2+ was detected. In the samples with x≥5 mol%, mixed valence states of copper ions were revealed. The FT-IR measurements indicate the presence in the glass structure of the distorted [ BiO 6] polyhedra, tri- and tetra-borate units ( BO 3, BO 4) and its dependence by the copper content.

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EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF IRON IONS IN THE 3B2O3·KF GLASS MATRIX

International Journal of Modern Physics B ◽

10.1142/s0217979204024501 ◽

2004 ◽

Vol 18 (10n11) ◽

pp. 1525-1535 ◽

Cited By ~ 6

Author(s):

I. ARDELEAN ◽

P. PASCUTA

Keyword(s):

Magnetic Susceptibility ◽

Iron Content ◽

Glass Matrix ◽

Structural Changes ◽

Magnetic Measurement ◽

Measurement Data ◽

Ionic Species ◽

Iron Ions ◽

Simultaneous Presence ◽

Valence States

Glasses of the x Fe 2 O 3·(100–x)[3 B 2 O 3· KF ] system, with 0<x≤35 mol %, were investigated by means of EPR and magnetic susceptibility measurements. When increasing the iron content the EPR absorption spectra undergo modification reflecting structural changes of the glass matrix and also the distribution and valence states of iron ions. The magnetic measurement data pointed out the character of interaction involving iron ions as depending on concentration and the simultaneous presence of both Fe 3+ and Fe 2+ ionic species.

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Structural and Magnetic Investigations of Fe2O3-B2O3-CaF2 Glass System

International Journal of Modern Physics B ◽

10.1142/s0217979203018430 ◽

2003 ◽

Vol 17 (13) ◽

pp. 2633-2641 ◽

Cited By ~ 4

Author(s):

I. Ardelean ◽

P. Pǎşcuţǎ ◽

V. Ioncu

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Mixed Oxide ◽

Glass System ◽

Iron Ions ◽

Structural Units ◽

Valence States ◽

Structural And Magnetic Properties

The structural and magnetic properties of a mixed oxide-fluoride vitreous matrix 3B 2 O 3· CaF 2 containing iron ions were investigated. Information concerning the structural units involving iron ions, their valence states and the type of interactions between them were obtained using EPR and magnetic susceptibility measurements.

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EPR and Magnetic Susceptibility Studies of Iron Ions in 3B2O3·CaCl2 Glass Matrix

International Journal of Modern Physics B ◽

10.1142/s0217979203021885 ◽

2003 ◽

Vol 17 (21) ◽

pp. 3889-3897 ◽

Cited By ~ 3

Author(s):

I. Ardelean ◽

P. Păşcuţă

Keyword(s):

Magnetic Susceptibility ◽

Glass Matrix ◽

Iron Ions ◽

Structural Units ◽

Valence States

Glass matrix 3B 2 O 3· CaCl 2 doped with iron ions up to 50 mol% were obtained and investigated by means of EPR and magnetic susceptibility. Information concerning the structural units involving iron ions, valence states and the type of the interactions between these ions were discussed.

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Effect of Magnesium Oxide Nanoparticles on Water Glass Structure

Archives of Foundry Engineering ◽

10.2478/v10266-012-0073-2 ◽

2012 ◽

Vol 12 (3) ◽

pp. 9-12 ◽

Cited By ~ 5

Author(s):

A. Bobrowski ◽

A. Kmita ◽

M. Starowicz ◽

B. Hutera ◽

B. Stypuła

Keyword(s):

Magnesium Oxide ◽

Water Glass ◽

Structural Changes ◽

Glass Structure ◽

Colloidal Suspensions ◽

Ir Absorption ◽

Structure Of Water ◽

Magnesium Oxide Nanoparticles ◽

Ir Absorption Spectra ◽

Ft Ir

Abstract An attempt has been made to determine the effect of an addition of colloidal suspensions of the nanoparticles of magnesium oxide on the structure of water glass, which is a binder for moulding and core sands. Nanoparticles of magnesium oxide MgO in propanol and ethanol were introduced in the same mass content (5wt.%) and structural changes were determined by measurement of the FT-IR absorption spectra.

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EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF B2O3–SrO–Fe2O3 GLASSES

Modern Physics Letters B ◽

10.1142/s0217984999000993 ◽

1999 ◽

Vol 13 (22n23) ◽

pp. 801-808 ◽

Cited By ~ 22

Author(s):

I. ARDELEAN ◽

G. SALVAN ◽

M. PETEANU ◽

V. SIMON ◽

C. HIMCINSCHI ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Magnetic Properties ◽

Magnetic Susceptibility ◽

Iron Ions ◽

Structural Units ◽

Paramagnetic Resonance ◽

Valence States ◽

Structural And Magnetic Properties ◽

Electron Paramagnetic ◽

Controlled Doping

Structural and magnetic properties of B 2 O 3– SrO – Fe 2 O 3 glasses were explored by a controlled doping of 2B 2 O 3· SrO vitreous matrix with iron oxide. The information concerning the structural units involving iron ions, their valence states and the types of interactions between them, was obtained using electron paramagnetic resonance (EPR) spectroscopy and magnetic susceptibility measurements.

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Near-IR Absorption Spectra for the Buckminsterfullerene Anions: An Experimental and Theoretical Study

10.21236/ada250532 ◽

1992 ◽

Author(s):

Del R. Lawson ◽

Daniel L. Feldheim ◽

Colby A. Foss ◽

Peter K. Dorhoug ◽

C. M. Elliott

Keyword(s):

Absorption Spectra ◽

Theoretical Study ◽

Ir Absorption ◽

Near Ir ◽

Ir Absorption Spectra

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Detection of Metal Toxicity Using Natural Phytoplankton as Test Organisms in the Great Lakes

Water Quality Research Journal ◽

10.2166/wqrj.1993.008 ◽

1993 ◽

Vol 28 (1) ◽

pp. 155-176

Author(s):

Mohiddin Munawari ◽

Milos Legner

Keyword(s):

Great Lakes ◽

Metal Toxicity ◽

Structural Changes ◽

System Response ◽

Turnover Rates ◽

High Turnover ◽

Spectra Analysis ◽

Test Organisms ◽

Future Potential ◽

Natural Phytoplankton

Abstract This paper presents an overview of techniques utilizing natural phytoplankton for the detection of metal-Induced stress in the Great Lakes. Both field and laboratory procedures are designed to evaluate either structural changes or functional response of test organisms. This up-to-date compendium provides a choice of techniques, which permits a holistic assessment of the stress caused by toxic metals. Recently introduced techniques, such as normalized size spectra analysis, flow cytometry, and the evaluation of a continuous-flow system response to metal toxicity, are discussed in more detail to explore their future potential. Owing to their key position in the food web, high turnover rates, abundance, and sensitivity to environmental perturbation, phytoplankton serve as reliable early warning indicators of ecosystem deterioration and its restoration.

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Cerium oxide nanomaterial with dual antioxidative scavenging potential: Synthesis and characterization

Journal of Biomaterials Applications ◽

10.1177/08853282211013451 ◽

2021 ◽

pp. 088532822110134

Author(s):

Sushant Singh ◽

Udit Kumar ◽

David Gittess ◽

Tamil S Sakthivel ◽

Balaashwin Babu ◽

...

Keyword(s):

Cerium Oxide ◽

Biological Systems ◽

Mixed Valence ◽

Stable Solution ◽

Ability To Act ◽

Valence States ◽

Transmission Electron ◽

Efficient Reduction ◽

Rich Media

Many studies have linked reactive oxygen species (ROS) to various diseases. Biomedical research has therefore sought a way to control and regulate ROS produced in biological systems. In recent years, cerium oxide nanoparticles (nanoceria, CNPs) have been pursued due to their ability to act as regenerative ROS scavengers. In particular, they are shown to have either superoxide dismutase (SOD) or catalase mimetic (CAT) potential depending on the ratio of Ce3+/Ce4+ valence states. Moreover, it has been demonstrated that SOD mimetic activity can be diminished by the presence of phosphate, which can be a problem given that many biological systems operate in a phosphate-rich environment. Herein, we report a CNP formulation with both SOD and catalase mimetic activity that is preserved in a phosphate-rich media. Characterization demonstrated a highly dispersed, stable solution of uniform-sized, spherical-elliptical shaped CNP of 12 ± 2 nm, as determined through dynamic light scattering, zeta potential, and transmission electron microscopy. Mixed valence states of Ce ions were observed via UV/Visible spectroscopy and XPS (Ce3+/Ce4+ > 1) (Ce3+∼ 62%). X-ray diffraction and XPS confirmed the presence of oxygen-deficient cerium oxide (CeO2-x) particles. Finally, the CNP demonstrated very good biocompatibility and efficient reduction of hydrogen peroxide under in-vitro conditions.

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