Wyniki wyszukiwania - Biblioteka Nauki

1

CREM in application to EPR dating technique

100%

Krzyminiewski R. , Frąckowiak M.

Geologos

|

2000

|

tom Vol. 5

65--75

EN

The paper illustrates the application of CREM (a method for enhancement of spectral resolution) to the EPR spectra of a sample of tooth enamel of a cave bear (J. Nietoperzowa = Bat Cave), mammoth bone (Halicz on the Dniester river) and calcite from cave dripstones (J. Czarna = Black Cave). The application of CREM enabled an accurate determination of positions of EPR spectra lines corresponding to paramagnetic centres. It was proved that the use of CREM enabled a determination of the influence of such physical processes as heating or irradiation, e.g. UV-irradiation, on the dynamics of the paramagnetic centres in a sample studied.

2

Bezpieczeństwo nowoczesnych elektrowni jądrowych

100%

Strupczewski A.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

|

2007

|

tom nr 132

275-285

PL

Elektrownie jądrowe z reaktorami PWR i BWR charakteryzują się wysokim poziomem bezpieczeństwa i nie powodują zagrożenia nawet przy największych awariach projektowych. Budowane obecnie elektrownie jądrowe III generacji, takie jak EPR i AP 1000, posiadają układy zaprojektowane tak, by nawet po ciężkich awariach ze stopieniem rdzenia elektrownia nie powodowała zagrożenia ani konieczności ewakuacji.

EN

Nuclear power plants with PWRs and BWRs are characterized by high safety level and do not raise hazards to population even in most demanding scenarios of design basis accidents. NPPs of III generation being presently built such as EPR or AP-1000 are provided with safety systems designed so that even after severe accidents with core melt there would be no radiological hazards and no necessity of evacuation of populations.

3

Procedury wyznaczania parametrów anizotropowego czynnika g dla centrów paramagnetycznych o spinie S = ½ zlokalizowanych w sieci krystalicznej

100%

Pawłowski M.

Materiały Elektroniczne

|

2011

|

tom T. 39, nr 4

31-38

PL

Elektronowy Rezonans Paramagnetyczny (EPR) jest użyteczną techniką badawczą służącą do określania natury i orientacji centrów magnetycznych (tj. obdarzonych spinem), które tworzą defekty punktowe w objętości badanego kryształu. Możliwość zebrania informacji o orientacji przestrzennej defektu stanowi o unikatowości spektroskopii EPR jako metody badawczej. Jednak aby z zarejestrowanego sygnału EPR wyciągnąć użyteczne informacje konieczna jest odpowiednia analiza zebranych danych. W niniejszej pracy przedstawione zostaną dwa sposoby podejścia do tego problemu.

EN

Electron Paramagnetic Resonance (EPR) is a useful research technique to determine the nature and orientation of the magnetic centers (ie with spin), which form point defects in the crystal volume. Oportunity to gather information about the spatial orientation of the defects determines the unique EPR spectroscopy as a method of research. However, to the registered EPR signal to get useful information it is essential to make correct analyze the collected date. In this paper will present two approaches to this problem.

4

Badanie nanocząstek magnetytu w pełnej krwi ludzkiej za pomocą elektronowego rezonansu paramagnetycznego

100%

Kubiak T. , Krzyminiewski R. , Dobosz B. , Schroeder G. , Kurczewska J. , Hałupka-Bryl M.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

|

2015

|

tom Vol. 21, nr 1

9--15

PL

Pomiary pokrytych PEG (poli(glikol etylenowy) nanocząstek magnetytu o średnicy rdzenia 10 nm wykonano metodą spektroskopii elektronowego rezonansu paramagnetycznego w zakresie temperatur 135–235 K. Badano nanocząstki znajdujące się w roztworze wodnym oraz w pełnej krwi ludzkiej. Przed dodaniem nanocząstek do krwi, zidentyfikowano naturalnie występujące w niej centra paramagnetyczne. Widmo EPR nanocząstek magnetytu miało postać szerokiej linii, której parametry silnie zależały od temperatury. W przypadku obu ośrodków zaobserwowano wzrost wartości współczynnika g wraz z obniżaniem temperatury środowiska. W przypadku nanocząstek w wodzie, schładzanie próbki do coraz niższych temperatur powodowało poszerzenie linii EPR, natomiast dla nanocząstek we krwi efekt ten był obserwowalny jedynie w przedziale temperatur od 190 do 235 K. Wartości parametrów linii EPR różniły się dla nanocząstek znajdujących się w dwóch ośrodkach (krwi i wodzie), co może wskazywać na wpływ środowiska na wzajemne interakcje nanocząstek.

EN

The measurements of PEG-coated magnetite nanoparticles (PEG – polyethyleneglicol) with a core diameter of 10 nm, were done by means of Electron Paramagnetic Resonance spectroscopy at the temperature range 135–235 K. Nanoparticles were examined in aqueous solution and in whole human blood. Paramagnetic centers naturally occurring in the blood were identified prior to the addition of nanoparticles. The EPR spectrum of magnetite nanoparticles has a form of a broad line, which parameters strongly depend on temperature. The increase in g-factor value was observed in case of both media, when the measurement temperature was being decreased. Gradual cooling of the sample of nanoparticles in water resulted in the broadening of the EPR line, whereas for nanoparticles in the blood this effect was only observed in the temperature range 190 to 235 K. The values of EPR line parameters were different for nanoparticles in two mentioned media (water and blood), which may indicate the influence of the environment on the interactions between nanoparticles.

5

EPR study of paramagnetic defects in clay minerals

100%

Babińska J. , Dyrek K. , Wyszomirski P.

Mineralogia

|

2007

|

tom Vol. 38, iss. 2

125--138

EN

Radiation induced defects (RID-s) and transition metal ion impurities were revealed by EPR (Electron Paramagnetic Resonance) spectroscopy in kaolinites from a number of Polish deposits. Arelationship between the intensity of the EPR signals of the RID-s and quantity of radioactive elements was defined in these minerals. In one of the deposits of kaolinites (Wyszonowice) the EPR signal intensity depends on grain size. Other clay minerals studied (illites, montmorillonites) only show weak signals of the RID type.

PL

Punktowe defekty strukturalne typu RID-s były badane metodą elektronowego rezonansu paramagnetycznego (EPR) w próbkach kaolinitu pochodzących z różnych złóż Polski. Stwierdzono w nich zależność między ilością defektów strukturalnych a zawartością pierwiastków promieniotwórczych. W przypadku kaolinitu pochodzącego z jednego ze złóż (Wyszonowice) sygnał EPR zależy też od uziarnienia minerału. Pozostałe badane minerały ilaste (illit, montmorillonit) ujawniają jedynie słabe sygnały typu RID.

6

O protokóle Ekerta w kryptografii kwantowej

100%

Czajkowski R. , Nowakowski W.

Elektronika : konstrukcje, technologie, zastosowania

|

2010

|

tom Vol. 51, nr 3

126-127

PL

W artykule podano ogólne informacje o zastosowaniu zjawiska EPR w kryptografii kwantowej (protokół Ekerta).

EN

General information about EPR and Ekert algorithm application in quantum cryptography is given.

7

Univalent iron monoazaetioporphyrin complexes studied by Mössbauer spectroscopy

94%

Kaczmarzyk T. , Dziliński K. , Sinyakov G. , Egorova G.

Nukleonika

|

2003

|

tom Vol. 48,suppl.1

31-34

EN

Results of Mössbauer and EPR studies of univalent-iron monoazaetioporphyrin complexes [Fe(I)(MAEP)] are presented in this paper. Fe(I)(MAEP) were generated using the chemical reduction method. Three forms of the univalent-iron monoazaetioporphyrin complexes were observed: (I) typical Fe(I)(MAEP), (II) with an additional electron on the porphyrin ligand [Fe(I)(MAEP•)]- and (III) the Fe(I)(MAEPh) phlorin structure. Electron configuration of Fe(I) ions in these complexes is (dxy)2(dxz ,dyz)4(dz 2)1. The [Fe(I)(MAEP•)]- structure is stable only in solution and it is transferred into Fe(I)(MAEP) in the solid state. Mössbauer parameters for all products of the reduction reaction are given.

8

Characterization and EPR studies of TiC and TiN ceramics at room temperature

94%

Bodziony T. , Guskos N. , Biedunkiewicz A. , Typek J. , Wróbel R. , Maryniak M.

Materials Science Poland

|

2005

|

tom Vol. 23, No. 4

899--907

EN

Four samples, namely TiC/C, TiN/C, (TiC + FexCy + Fe)/C and TiN/amorphous carbon, have been prepared and investigated. In the former three samples titanium compounds were placed in a carbon matrix, while in the fourth one TiN was surrounded by an amorphous carbon. The samples have been characterized by XRD, SEM, and electron diffraction spectroscopy. The crystallite sizes and lattice parameters of TiC and TiN have been determined by the X-ray diffraction method. XRD measurements have shown that the lattice constants of nanosized samples were smaller than those of microsized samples. An essential influence of the carbon matrix during the crystallization process on the lattice parameters and grain size was observed. Electron paramagnetic resonance (EPR) measurements of the samples were carried out at room temperature. A narrow EPR absorption line has been recorded for the TiC/C, TiN/C, and TiN/amorphous carbon samples, whereas for the (TiC + FexCy + Fe)/C sample a ferromagnetic resonance spectrum, mainly of ?-Fe and cementite Fe3C, has been recorded. The narrow resonance EPR line is explained by carrier motion - free electrons in the case of the TiN/C sample and holes (carbon vacancies) in the case of TiC/C and TiN/amorphous carbon samples - which could lead to the creation of the pseudogap state in TiCx or TiNx compounds.

9

Some implications of the nonlinear properties of SASD crystals

94%

Lipiński I. E. , Kuriata J.

Materials Science Poland

|

2005

|

tom Vol. 23, No. 4

1023--1027

EN

The paper deals with the results of optical and EPR measurements performed on single-crystallineand powdered samples of sodium ammonium sulphate dihydrate (SASD) and sodium ammonium selenate dihydrate (SASeD) doped with Cr3+ and irradiated with X-rays. It is shown that for samples doped with Cr3+ one detects in the optical spectrum, apart from the existence of two broad transmission bands, yet another narrow band, corresponding to the 4A2g(F) › 4T1g(F) transition, which suggests that such samples can potentially exhibit laser action. The EPR spectra of X-ray irradiated pure samples of SASD crystals indicate that a variety of paramagnetic centres (NH4- , SO4-n ) are easily induced by irradiation. The concentrations of these centres are in close relation with the dose of irradiation. The observed relation can be used for dosimetry purposes.

10

Magnetic resonance study of M3Fe4V6O24 (M = Mg, Zn, Mn, Cu, Co) compounds

94%

Guskos N. , Typek J. , Zolnierkiewicz G. , Blonska-Tabero A. , Kurzawa M. , Bosacka M.

Materials Science Poland

|

2005

|

tom Vol. 23, No. 4

923--928

EN

Multicomponent vanadates, M3Fe4V6O24 (M = Mg(II), Mn(II), Zn(II), Co(II) and Cu(II)), have been synthesized by the solid-state reaction method using a stoichiometric mixture of MO, Fe2O3, and V2O5 oxides. They crystallize in the triclinic space ace group P1 and have a complicated structure with two metal ion subsystems. Electron paramagnetic resonance (EPR) measurements have been performed at room temperature and an intense, almost symmetric EPR lines were recorded for all investigated samples except Co3Fe4V6O24. The integral intensity and linewidth of this line essentially depends on the kind of M(II) metal ion in the crystalline matrix. The EPR line intensity for the sample Co3Fe4V6O24 is over one order of magnitude smaller than for all other investigated compounds, and the position of its resonance line is shifted towards lower magnetic fields. The difference in linewidths and intensities are due to the various magnetic interactions between magnetic ions in the lattice, especially for systems containing two different magnetic ions.

11

Electronic properties of M2InV3O11 (M(II) = Zn(II) and Co(II)) compounds

94%

Guskos N. , Glenis S. , Karkas K. , Zolnierkiewicz G. , Bosacka M.

Materials Science Poland

|

2013

|

tom Vol. 31, No. 1

25-28

EN

The electronic properties of multicomponent vanadate oxides M2InV3O11 (M(II) = Zn(II) and Co(II)) were investigated by electrical resistivity and electron paramagnetic resonance (EPR) measurements. Replacement of non-magnetic Zn(II) cations with magnetic Co(II) ions resulted in a significant drop in the electrical conductivity and an increase in the activation energy. The EPR spectroscopy revealed the presence of VO2+ vanadyl ions in both compounds, while the presence of divalent cobalt ions was identified in the Co2InV3O11 oxide at low temperatures. The concentration of VO2+ vanadyl ions was found to be about one order higher for the vanadate oxide without magnetic ions. It is suggested that the increased concentration of VO2+ ions could be responsible for the enhanced conductivity of Zn2InV3O11.

12

Dyson line and modified Dyson line in the EPR measurements

94%

Popovych V. , Bester M. , Stefaniuk I. , Kuzma M.

Nukleonika

|

2015

|

tom 60

|

nr 3

385-388

EN

The difficulty in determining the electron paramagnetic resonance (EPR) line parameters of ferromagnetic semiconductors has been addressed. For these materials, the resonance line is very broad and lies at low resonance field, so that only a part of the line can be detected experimentally. Moreover, the line is of asymmetric (Dysonian) shape as described by the line shape parameter α. We have compared values of line parameters derived by computer fitting of the whole experimental EPR line to the Dyson function (or modified Dyson function) with the values obtained by applying this procedure to the left and the right half of the line.

13

Effect of microwave power on EPR spectra of natural and synthetic dental biocompatible materials

94%

Adamczyk J. , Ramos P. , Pilawa B.

Nukleonika

|

2015

|

tom 60

|

nr 3

449-453

EN

Paramagnetic centers in the two exemplary synthetic and natural dental biocompatible materials applied in implantology were examined by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra were measured in the range of microwave power 2.2–70 mW. The aims of this work were to compare paramagnetic centers concentrations in different dental biocompatible materials and to determine the effect of microwave power on parameters of their EPR spectra. It is the very first and innovatory examination of paramagnetic centers in these materials. It was pointed out that paramagnetic centers existed in both natural (~1018 spin/g) and synthetic (~1019 spin/g) dental biocompatible materials, but the lower free radical concentration characterized the natural sample. Continuous microwave saturation of EPR spectra indicated that faster spin-lattice relaxation processes existed in synthetic dental biocompatible materials than in natural material. Linewidths (ΔBpp) of the EPR spectra of the natural dental material slightly increased for the higher microwave powers. Such effect was not observed for the synthetic material. The broad EPR lines (ΔBpp): 2.4 mT, 3.9 mT, were measured for the natural and synthetic dental materials, respectively. Probably strong dipolar interactions between paramagnetic centers in the studied samples may be responsible for their line broadening. EPR spectroscopy is the useful experimental method in the examination of paramagnetic centers in dental biocompatible materials.

14

Growth and EPR properties of ErVO4single crystals

94%

Leniec G. , Kaczmarek S. M. , Berkowski M. , Głowacki M. , Skibiński T. , Bojanowski B.

Nukleonika

|

2015

|

tom 60

|

nr 3

405-410

EN

Single crystals of ErVO4 were grown by the Czochralski method under ambient pressure in a nitrogen atmosphere. Obtained crystals were transparent with strong pink coloring. Electron paramagnetic resonance (EPR) spectra were recorded as a function of the applied magnetic field. Temperature and angular dependences of the EPR spectra of the samples in the 3–300 K temperature range were analyzed applying both Lorentzian––Gauss approximation for diluted medium and Dyson for dense magnetic medium. EPR-NMR program was done to find local symmetry and spin Hamiltonian parameters of erbium ions.

15

Druga rewolucja kwantowa: dziedzictwo Johna S. Bella

94%

Pabjan T.

Zagadnienia Filozoficzne w Nauce

|

2011

|

nr 49

123-137

PL

The history of quantum mechanics is divided into two periods which are labeled as the ﬁrst and the second quantum revolutions. During the ﬁrst of these periods mathematical formalism of quantum theory was formulated and interpreted, during the second – new quantum technologies were developed. It turns out that conceptual revolution of the ﬁrst period enabled technological revolution of the second. In this article it is argued, that Irish physicist, John S. Bell, played an important role in the process of triggering the second quantum revolution. His work on quantum entanglement of the EPR particles made possible elaborating some new methods and theoretical approaches clarifying the quantum description of single objects. These methods and approaches became the core of new scientiﬁc domains which are hybrids of quantum mechanics and some classical sciences. The quantum cryptography and the quantum computation are examples of such domains and in the paper special attention is paid to them. It is showed that theoretical analyses of John S. Bell provide a conceptual background for these disciplines and this is why it’s not improper to call this physicist – as Alain Aspect did – a prophet of the second quantum revolution.

16

The Synthesis and Spectroscopic Study of Novel Binuclear Chromium(III) Complex with Pipemidic Acid

94%

Skrzypek D. , Kovala-Demertzi D. , Szymanska-Niewiadomska B. , Kourkoumelis N. , Staninska M.

Polish Journal of Chemistry

|

2009

|

tom Vol. 83, nr 3

363-371

EN

The interaction of Cr(III) with pipemidic acid, Hpipem, afforded the complex [Cr(pipem)(HO)2(H2O)]2 Cr2O3. The new complex has been characterized by elemental analysis, infrared, XRD and EPR spectroscopy. The EPR spectra of the complex have been recorded down to T = 3 K. The temperature dependence of EPR spectrum demonstrates that spectrum originates from septet transitions at a room temperature and from quintet state for lower temperatures for exchange coupled chromium pairs. The dimer characterizes antiferromagnetic interaction with J = -32 cm-1. The monoanion, pipem, exhibits obligation through the carbonyl and carboxylatooxygen atoms. Six-coordinate dimer distorted octahedral configuration has been proposed for [Cr(pipem)(HO)2(H2O)]2.

17

EPR and ESEEM study of silver clusters in ZK-4 molecular sieves

94%

Sadło J. , Michalik J. , Kevan L.

Nukleonika

|

2006

|

tom Vol. 51,suppl.1

49-54

EN

Silver clusters generated by g-irradiation in ZK-4 zeolites – isostructural with Linde type A (LTA) zeolite, have been studied by electron paramagnetic resonance (EPR) spectroscopy. It was shown that even a small decrease of cation capacity resulting from a lower Si/Al ratio in the framework affects distinctly silver agglomeration. In dehydrated ZK-4 with Si/Al = 1.2 and 2.4 only silver dimers are stabilized, whereas in Linde 4A silver hexamers were trapped. In ZK-4 exposed to H2O and CH3OH, silver tetramers Ag43+ efficiently are formed. The results of electron spin echo envelope modulation (ESEEM) showed that the adsorbate molecules are in close vicinity to the clusters. It was postulated that in zeolites with low cation capacity the adsorbate molecules make difficult Ag0 migration promoting the reactions with Ag+ cations located in the same sodalite cage.

18

Dyson line and modified Dyson line in the EPR measurements

94%

Popovych V. , Bester M. , Stefaniuk I. , Kuzma M.

Nukleonika

|

2015

|

tom Vol. 60, No. 3, part 1

385--388

EN

The difficulty in determining the electron paramagnetic resonance (EPR) line parameters of ferromagnetic semiconductors has been addressed. For these materials, the resonance line is very broad and lies at low resonance fi eld, so that only a part of the line can be detected experimentally. Moreover, the line is of asymmetric (Dysonian) shape as described by the line shape parameter α. We have compared values of line parameters derived by computer fi tting of the whole experimental EPR line to the Dyson function (or modified Dyson function) with the values obtained by applying this procedure to the left and the right half of the line.

19

Functionalization of polymer surfaces by radiation-induced grafting

94%

Przybytniak G. , Kornacka E. M. , Mirkowski K. , Walo M. , Zimek Z.

Nukleonika

|

2008

|

tom Vol. 53, No. 3

89-95

EN

The mutual radiation grafting of acrylic acid (AAc) onto polyethylene (PE), polypropylene (PP) and polystyrene (PS) films was performed. At first stage of investigations, the influence of ionizing radiation on the trunk polymers was studied, i.e. the level of radicals stable at room temperature and radiation yield of evolved hydrogen were estimated for each polymer. The measurements were carried out using electron paramagnetic resonance (EPR) spectroscopy and gas chromatography (GC), respectively. Radiation yields of radicals as well as hydrogen emission increased in the following order PS < PP < PE. Under comparable conditions, the same relationship was found for the yield of radiation-induced grafting of AAc. A distinct correlation between content of radicals generated by ionizing radiation in polymeric matrices and grafting degree was confirmed for the studied materials. The effect of monomer and inhibitor concentrations on the efficiency of processes were studied as well.

20

Security of Electronic Patient Record using Imperceptible DCT-SVD based Audio Watermarking Technique

94%

Kanhe A. , Gnanasekaran A.

International Journal of Electronics and Telecommunications

|

2019

|

tom Vol. 65, No. 1

19--24

EN

A robust and highly imperceptible audio watermarking technique is presented to secure the electronic patient record of Parkinson’s Disease (PD) affected patient. The proposed DCT-SVD based watermarking technique introduces minimal changes in speech such that the accuracy in classification of PD affected person’s speech and healthy person’s speech is retained. To achieve high imperceptibility the voiced part of the speech is considered for embedding the watermark. It is shown that the proposed watermarking technique is robust to common signal processing attacks. The practicability of the proposed technique is tested: by creating an android application to record & watermark the speech signal. The classification of PD affected speech is done using Support Vector Machine (SVM) classifier in cloud server.