EPR INVESTIGATIONS OF CuO-B2O3-PbO-Ag2O GLASSES

2009 ◽  
Vol 23 (05) ◽  
pp. 747-753
Author(s):  
VIOREL TIMAR ◽  
RALUCA CICEO-LUCÃCEL ◽  
OCTAVIA HULPUŞ ◽  
IOAN ARDELEAN
Keyword(s):  
Copper Content ◽  
Structural Modification ◽  
Magnetic Interactions ◽  
Paramagnetic Resonance ◽  
Distorted Octahedral ◽  
Structural Details ◽  
Paramagnetic Probes ◽  
Parallel Band ◽  
Electron Paramagnetic ◽  
Epr Experiments

Glasses of the x CuO · (100 - x)[3 B 2 O 3· 0.9 PbO · 0.1 Ag 2 O ] system, with 0.5 ≤ x ≤ 10 mol %, were prepared and investigated by means of electron paramagnetic resonance (EPR) measurements. Structural details of different diamagnetic vitreous systems may be revealed by the Cu 2+ ions, frequently used as paramagnetic probes in EPR experiments. The shape and the intensity of the recorded EPR lines are dependent on the CuO content. The EPR spectra are asymmetric, with characteristics for Cu 2+ (3d9) ions in axially-distorted octahedral symmetric sites. Due to the interaction of the unpaired electron spin (s = 1/2) with the nuclear one (I = 3/2) of Cu 2+ ions, the characteristic hyperfine structure (hfs) is visible for small concentrations of CuO in both spectra bands (parallel and perpendicular). The increasing of copper content in the samples generates the EPR absorption spectra modification, the hfs being resolved in the parallel band of the spectra in whole compositional range, while in the perpendicular band, hfs disappear for x > 3 mol %. This fact indicates the structural modification in Cu 2+ vicinity and possible magnetic interactions.

scholarly journals Intracellular Hypoxia of Tumor Tissue Estimated by Noninvasive Electron Paramagnetic Resonance Oximetry Technique Using Paramagnetic Probes

2011 ◽  
Vol 34 (1) ◽  
pp. 142-145 ◽  
Author(s):  
Atsuko Matsumoto ◽  
Ken-ichiro Matsumoto ◽  
Shingo Matsumoto ◽  
Fuminori Hyodo ◽  
Anastasia L. Sowers ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Tumor Tissue ◽  
Paramagnetic Resonance ◽  
Paramagnetic Probes ◽  
Electron Paramagnetic

scholarly journals Electron paramagnetic resonance monitoring of ischemia-induced myocardial oxygen depletion and acidosis in isolated rat hearts using soluble paramagnetic probes

2011 ◽  
Vol 68 (2) ◽  
pp. 649-655 ◽  
Author(s):  
Denis A. Komarov ◽  
Ilirian Dhimitruka ◽  
Igor A. Kirilyuk ◽  
Dmitrii G. Trofimiov ◽  
Igor A. Grigor'ev ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Oxygen Depletion ◽  
Paramagnetic Resonance ◽  
Rat Hearts ◽  
Paramagnetic Probes ◽  
Electron Paramagnetic ◽  
Isolated Rat

Growth and EPR properties of KSm(WO4)2 and KEr(WO4)2 single crystals

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Grzegorz Leniec ◽  
Tomasz Skibiński ◽  
Slawomir Kaczmarek ◽  
Przemyslaw Iwanowski ◽  
Marek Berkowski
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Structure ◽  
Single Crystals ◽  
Angular Dependence ◽  
Growth Conditions ◽  
Magnetic Interactions ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Temperature Dependences ◽  
Electron Paramagnetic

AbstractGrowth conditions and electron paramagnetic resonance investigations of two well oriented KSm(WO4)2 and KEr(WO4)2 single crystals have been presented and discussed. Hyperfine structure of Sm3+ ion was detected and analyzed for angular and temperature dependences. EPR spectra of KEr(WO4)2 and its angular dependence showed the presence of 5 magnetically nonequivalent Er centers in the crystal. A change in the type of magnetic interactions was analyzed using mixed (Gaussian and Lorentzian) fits of the EPR spectra.

NOISE INDUCED PHENOMENA IN ELECTRON PARAMAGNETIC RESONANCE SYSTEMS

1992 ◽  
Vol 06 (04) ◽  
pp. 197-201 ◽  
Author(s):  
L. GAMMAITONI ◽  
M. MARTINELLI ◽  
L. PARDI ◽  
S. SANTUCCI
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Stochastic Resonance ◽  
Cooperative Effect ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Epr Experiments

Evidence of noise induced effects in electron-paramagnetic-resonance (EPR) experiments is reported. The phenomenon of Stochastic Resonance is presented and discussed as a cooperative effect between the noise and an external periodic driving, due to the bistable character of the EPR system.

Reacted copper(II) concentrations in earlywood and latewood of micronized copper-treated Canadian softwood species

Holzforschung ◽  
2015 ◽  
Vol 69 (4) ◽  
pp. 509-512 ◽  
Author(s):  
Wei Xue ◽  
Pierre Kennepohl ◽  
John N.R. Ruddick
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Fluorescence Spectroscopy ◽  
Copper Content ◽  
Red Pine ◽  
Western Hemlock ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Total Copper ◽  
Electron Paramagnetic ◽  
Softwood Species

Abstract Electron paramagnetic resonance was used in conjunction with X-ray fluorescence spectroscopy to quantify total copper and reacted copper retentions in MCQ and MCA treated Canadian red pine sapwood and western hemlock heartwood. Total copper retentions were distinctly different between earlywood and latewood of both softwood species examined. Earlywood of red pine sapwood had higher total copper content than the latewood, while western hemlock heartwood had higher total copper contents in latewood than earlywood. The reacted copper concentrations were similar in earlywood and latewood, reflecting a similar capacity of each to solubilize and complex the reacted copper.

scholarly journals Extending electron paramagnetic resonance to nanoliter volume protein single crystals using a self-resonant microhelix

2019 ◽  
Vol 5 (10) ◽  
pp. eaay1394 ◽  
Author(s):  
Jason W. Sidabras ◽  
Jifu Duan ◽  
Martin Winkler ◽  
Thomas Happe ◽  
Rana Hussein ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Active Site ◽  
Measured Signal ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
X Ray Crystallography ◽  
X Band ◽  
Electron Paramagnetic ◽  
Epr Experiments

Electron paramagnetic resonance (EPR) spectroscopy on protein single crystals is the ultimate method for determining the electronic structure of paramagnetic intermediates at the active site of an enzyme and relating the magnetic tensor to a molecular structure. However, crystals of dimensions typical for protein crystallography (0.05 to 0.3mm) provide insufficient signal intensity. In this work, we present a microwave self-resonant microhelix for nanoliter samples that can be implemented in a commercial X-band (9.5 GHz) EPR spectrometer. The self-resonant microhelix provides a measured signal-to-noise improvement up to a factor of 28 with respect to commercial EPR resonators. This work opens up the possibility to use advanced EPR techniques for studying protein single crystals of dimensions typical for x-ray crystallography. The technique is demonstrated by EPR experiments on single crystal [FeFe]-hydrogenase (Clostridium pasteurianum; CpI) with dimensions of 0.3 mm by 0.1 mm by 0.1 mm, yielding a proposed g-tensor orientation of the Hox state.

scholarly journals High temperature EPR study of the M3Fe4V6O24 (M = Cu, Zn, Mg and Mn)

2016 ◽  
Vol 34 (3) ◽  
pp. 517-522 ◽  
Author(s):  
Niko Guskos ◽  
Grzegorz Zolnierkiewicz ◽  
Janusz Typek ◽  
Malwina Pilarska ◽  
Constantinos Aidinis ◽  
...  
Keyword(s):  
High Temperature ◽  
Resonance Field ◽  
Spin Systems ◽  
Magnetic Interactions ◽  
Paramagnetic Resonance ◽  
Integrated Intensity ◽  
Epr Parameters ◽  
Magnetic Ions ◽  
Electron Paramagnetic

AbstractElectron paramagnetic resonance (EPR) spectra of M3Fe4V6O24 (M = Cu, Zn, Mg and Mn) compounds in high temperature range (293 K to 493 K) have been investigated. The role of magnetic (Cu, Mn) and non-magnetic (Zn, Mg) ions in M3Fe4V6O24 structure in formation of magnetic resonance spectra was studied. Temperature dependence of EPR parameters: resonance field, linewidth and integrated intensity were examined. Similarities and differences in temperature behavior of these parameters has been discussed in terms of different relaxation mechanisms and magnetic interactions in the spin systems. An important role of additional magnetic ions (M = Mn or Cu) in the M3Fe4V6O24 structure has been identified and its consequences considered.

Sign in / Sign up

Export Citation Format

Share Document