EPR Investigation of Defects in Boron Nitride thin Films

1992 ◽  
Vol 242 ◽  
Author(s):  
M. Fanciulli ◽  
T. D. Moustakas
Keyword(s):  
Thin Films ◽  
Nitrogen Vacancy ◽  
Carbon Doping ◽  
Carbon Incorporation ◽  
Paramagnetic Resonance ◽  
Nitrogen Incorporation ◽  
Argon Discharge ◽  
Epr Signal ◽  
Cubic Structure ◽  
Electron Paramagnetic

ABSTRACTDefects in BN thin films, produced by reactive sputtering, were investigated by Electron Paramagnetic Resonance (EPR) measurements. The EPR signals of films produced with up to 10% N2 in the argon discharge are consistent with films having a cubic structure, and becoming more ordered with nitrogen incorporation in the films. The concentration of spins is in the order of 1019 spins/g and they are attributed to nitrogen vacancies with an electron trapped in. Carbon incorporation changes the EPR signal and increases the concentration of spins significantly. This result is consistent with the notion that carbon doping stabilizes the electron in a nitrogen vacancy.

Room Temperature Electron Paramagnetic Resonance (EPR) Signal Storage

1969 ◽  
Author(s):  
D.A. Bozanic ◽  
D.C. Buck ◽  
F.H. Harris ◽  
R.E. Huber ◽  
D. Mergerian ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Epr Signal ◽  
Electron Paramagnetic

Evaluation of systemic blood NO dynamics by EPR spectroscopy: HbNO as an endogenous index of NO

2003 ◽  
Vol 285 (2) ◽  
pp. H589-H596 ◽  
Author(s):  
Kazuyoshi Kirima ◽  
Koichiro Tsuchiya ◽  
Hiroyoshi Sei ◽  
Toyoshi Hasegawa ◽  
Michiyo Shikishima ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Whole Blood ◽  
Computer Assisted ◽  
Subtraction Method ◽  
Epr Spectrum ◽  
Systemic Blood ◽  
Paramagnetic Resonance ◽  
Species Overlap ◽  
Epr Signal ◽  
Electron Paramagnetic

The measurement of hemoglobin-nitric oxide (NO) adduct (HbNO) in whole blood by the electron paramagnetic resonance (EPR) method seems relevant for the assessment of systemic NO levels. However, ceruloplasmin and unknown radical species overlap the same magnetic field as that of HbNO. To reveal the EPR spectrum of HbNO, we then introduced the EPR signal subtraction method, which is based on the computer-assisted subtraction of the digitized EPR spectrum of HbNO-depleted blood from that of sample blood using the software. Rats were treated with Nω-nitro-l-arginine methyl ester (l-NAME; 120 mg · kg–1 · day–1) for 1 wk to obtain HbNO-depleted blood. When this method was applied to the analysis of untreated fresh whole blood, the five-coordinate state of HbNO was observed. HbNO concentration in pentobarbital-anesthetized rats was augmented (change in [HbNO] = 1.6–5.5 μM) by infusion of l-arginine (0.2–0.6 g/kg) but not d-arginine. Using this method, we attempted to evaluate the effects of temocapril on HbNO dynamics in an l-NAME-induced rat endothelial dysfunction model. The oral administration of l-NAME for 2 wk induced a serious hypertension, and the HbNO concentration was reduced (change in [HbNO] = 5.7 μM). Coadministration of temocapril dose dependently improved both changes in blood pressure and the systemic HbNO concentration. In this study, we succeeded in measuring the blood HbNO level as an index of NO by the EPR HbNO signal subtraction method. We also demonstrated that temocapril improves abnormalities of NO dynamics in l-NAME-induced endothelial dysfunction rats using the EPR HbNO signal subtraction method.

Quantification of mobilized copper(II) levels in micronized copper-treated wood by electron paramagnetic resonance (EPR) spectroscopy

Holzforschung ◽  
2013 ◽  
Vol 67 (7) ◽  
pp. 815-823 ◽  
Author(s):  
Wei Xue ◽  
Pierre Kennepohl ◽  
John N.R. Ruddick
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectroscopy ◽  
Treated Wood ◽  
Spectral Parameters ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Acid Reaction ◽  
Epr Signal ◽  
Electron Paramagnetic ◽  
Reference Samples

Abstract Sapwood sawdust from southern pine was treated with micronized copper (MC) under various conditions and the mobilized copper(II) (Cumob) concentrations were determined in the treated wood by electron paramagnetic resonance (EPR) spectroscopy. The spectral parameters for the copper sulfate (CuSO4)-treated sapwood and those of the MC-treated sapwood were very similar. A linear correlation was found between the intensities of copper (Cu) EPR spectra and those of Cu energy-dispersive X-ray fluorescence spectroscopy in a series of CuSO4-treated sapwood reference samples. Thus, the EPR signal intensities could be reliably correlated to the mass of reacted Cu present using this calibration curve. The amount of the Cumob in sawdust treated by MC suspensions increased during the first 2–3 days after the initial treatment and then reached a maximum during the 7-day monitoring period. In the case of the treatment with MC alone or MC azole, an increased MC concentration led to an elevated amount of Cu (to a maximum of ∼0.23% Cu) solubilized by the sapwood. If the wood was treated with MC quat, the Cumob initially increased, but at higher concentrations the Cumob content decreased, due to the interference by the quat cobiocide on the acid reaction between the wood and the basic Cu carbonate. An examination of commercially-treated wood confirmed the laboratory observations.

Nitrogen Centers in Nanodiamonds: EPR Studies

2010 ◽  
Vol 645-648 ◽  
pp. 1239-1242 ◽  
Author(s):  
Alexandra A. Soltamova ◽  
P.G. Baranov ◽  
Ivan V. Ilyin ◽  
A.Y. Vul' ◽  
S.V. Kidalov ◽  
...  
Keyword(s):  
Spin Echo ◽  
Natural Diamond ◽  
Electron Spin Echo ◽  
Atomic Nitrogen ◽  
Paramagnetic Resonance ◽  
W Band ◽  
High Pressure High Temperature ◽  
X Band ◽  
Epr Signal ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) and electron spin echo (ESE) at X-band (9.4 GHz) and W-band (94 GHz) have been used to study defects in natural diamond nanocrystals, detonation nanodiamond (ND) with a size of  4.5 nm and detonation ND after high-pressure high-temperature (HTHP) sintering with a size of  8.5 nm. Based on identification of atomic nitrogen centers N0 and nitrogen pairs N2+ detected by means of the high frequency EPR and ESE in natural diamond nanocrystals, atomic nitrogen centers N0 have been discovered in nanodiamond core in detonation ND and detonation ND after sintering. In addition EPR signal of multi-vacancy centers with spin 3/2 seems to be observed in diamond core of detonation ND.

scholarly journals DEPENDENCE OF ELECTRON PARAMAGNETIC RESONANCE (EPR) SPECTRUM PARAMETERS ON THE KIND OF MEAT AND FISH TREATED BY IONIZING RADIATION

2018 ◽  
Vol 97 (9) ◽  
pp. 873-876
Author(s):  
R. T. Timakova ◽  
Sergei L. Tikhonov ◽  
O. V. Evdokimova ◽  
I. V. Butenko
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ionizing Radiation ◽  
Bone Tissue ◽  
Radiation Treatment ◽  
Raw Materials ◽  
Food Products ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Epr Signal ◽  
Electron Paramagnetic

Regulation of the use of ionizing radiation for treating food products and agricultural raw materials in Russia in 2017 suggests a wide dissemination of radiation technologies in the food industry, but manufacturers of food products processed by ionizing radiation do not indicate on the label the relevant information. Because of this, the identification of the domestic consumer market of food products processed by ionizing radiation will reduce the number of violations of requirements of state standard State standards (GOST) 33800-2016 “Production of food irradiated. General labeling requirements”. To determine whether irradiation of food raw materials and foodstuff, used the method of electron paramagnetic resonance (EPR), with each of the food products treated by ionizing radiation has its own characteristic EPR spectrum. In this regard, the aim of the research is to identify the dependence of the parameters of the EPR spectrum from meat, fish and poultry treated with ionizing radiation. Samples of bone tissue (SBT) meat, fish and poultry were subjected to radiation treatment with a linear electron accelerator model UELR-10-10С2 with energies up to 10 MeV. Studies of samples were carried out on the portable automated EPR spectrometer brand Labrador Expert X-band. Found that despite treatment samples of bone tissue with the same dose of ionizing radiation (12 kGy), the EPR signal depends on the type of vertebrates, the structure of the tissue sample, and other factors. Bone samples of beef and pork have a higher sensitivity to irradiation. Recorded a steady correlation between increasing the area of the EPR signal parameters: amplitude is of 0.99, the width of the peak signal, respectively 0,979 (the degree of strength of statistical relationships Chedoke very high). Processing of the obtained results of the EPR spectrum provides a high degree of confidence (p≤0.05) to identify how previously non-irradiated and radiation-processed various meats, fish and poultry.

Local zincblende coordination in heteroepitaxial wurtzite Zn1−xMgxO:Mn thin films with 0.01 ≤ x ≤ 0.04 identified by electron paramagnetic resonance

2015 ◽  
Vol 3 (45) ◽  
pp. 11918-11929 ◽  
Author(s):  
Rolf Böttcher ◽  
Michael Lorenz ◽  
Andreas Pöppl ◽  
Daniel Spemann ◽  
Marius Grundmann
Keyword(s):  
Thin Films ◽  
Electron Paramagnetic Resonance ◽  
Stacking Faults ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

Heteroepitaxial Zn1−xMgxO:Mn thin films show already atx= 0.01 a local cubic zincblende coordination attributed to stacking faults.

Nitrite is an alternative source of NO in vivo

2005 ◽  
Vol 288 (5) ◽  
pp. H2163-H2170 ◽  
Author(s):  
Koichiro Tsuchiya ◽  
Yasuhisa Kanematsu ◽  
Masanori Yoshizumi ◽  
Hideki Ohnishi ◽  
Kazuyoshi Kirima ◽  
...  
Keyword(s):  
Dependent Manner ◽  
Alternative Source ◽  
Paramagnetic Resonance ◽  
Induced Hypertension ◽  
Epr Signal ◽  
Nitrite Nitrate ◽  
Electron Paramagnetic ◽  
Dose Dependent ◽  
Peak Blood

In this study, we investigated whether orally administered nitrite is changed to NO and whether nitrite attenuates hypertension in a dose-dependent manner. We utilized a stable isotope of [15N]nitrite (15NO2−) as a source of nitrite to distinguish between endogenous nitrite and that exogenously administered and measured hemoglobin (Hb)-NO as an index of circulating NO in whole blood using electron paramagnetic resonance (EPR) spectroscopy. When 1 mg/kg Na15NO2 was orally administered to rats, an apparent EPR signal derived from Hb15NO ( AZ = 23.4 gauss) appeared in the blood. The peak blood HbNO concentration occurred at the first measurement after intake (5 min) for treatment with 1 and 3 mg/kg (HbNO: 4.93 ± 0.52 and 10.58 ± 0.40 μM, respectively) and at 15 min with 10 mg/kg (HbNO: 38.27 ± 9.23 μM). In addition, coadministration of nitrite (100 mg/l drinking water) with Nω-nitro-l-arginine methyl ester (l-NAME; 1 g/l) for 3 wk significantly attenuated the l-NAME-induced hypertension (149 ± 10 mmHg) compared with l-NAME alone (170 ± 13 mmHg). Furthermore, this phenomenon was associated with an increase in circulating HbNO. Our findings clearly indicate that orally ingested nitrite can be an alternative to l-arginine as a source of NO in vivo and may explain, at least in part, the mechanism of the nitrite/nitrate-rich Dietary Approaches to Stop Hypertension diet-induced hypotensive effects.

Electron Paramagnetic Resonance Study of Ion-Implanted Photorefractive Crystals

1997 ◽  
Vol 504 ◽  
Author(s):  
A. Darwish ◽  
D. Ila ◽  
E. K. Willams ◽  
D. B. Poker ◽  
D. K. Hensley
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ion Implantation ◽  
Room Temperature ◽  
Electron Paramagnetic Resonance Study ◽  
Paramagnetic Resonance ◽  
Photorefractive Crystals ◽  
Laser Illumination ◽  
Epr Signal ◽  
Electron Paramagnetic

ABSTRACTThe effect of the ion implantation (Fe) on LiNbO3, MgO, and A12O3 crystals is studied using electron paramagnetic resonance (EPR). EPR measurements on these crystals were performed as a function of fluence at room temperature. The fluence was 1 × 1014 and 1 × 1016 ions/cm2. The unpaired carrier concentration increases with increasing fluence. The photosensitivity of these crystals was determined by observing in situ the effect of the laser illumination on the EPR signal and measuring the decay and the growth of the EPR signal. The EPR signal of Fe3+ was found to decrease in both MgO, and Al2O3; and was found to increase in LiNbO3. This indicated that in case of MgO, and A12O3 Fe3+ will transfer into Fe2+/Fe4+, but in case of LiNbO3 Fe2+/ Fe4+ will transfer into Fe3+; increasing the EPR signal. This was found primary due to some Fe2+ and Fe4+ ions, which is not intentionally doped on the LiNbO3 crystal but exist as a defect on the crystal.

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