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1

Synthesis of Conductive Cocoon Silk Composites

Kaitsuka Y., Goto H.

Fibres & Textiles in Eastern Europe

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2017

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Vol. 25, no. 1 (121)

17--23

EN

Herein we report on the preparation of polyaniline (PANI) composite using a cocoon by in situ chemical oxidative polymerisation. The composites thus prepared were characterised by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), infrared (IR), and electron spin resonance (ESR) spectroscopy. We confirmed the PANI/cocoon composite and subsequent carbonisation allowed the formation of micro-sized wafer-shaped carbon. The polymerisation reaction occurs in a chiral reaction field of the silk surface, which can be referred to as bio-interface polymerisation.

PL

W artykule opisano przygotowanie polianilinowych (PANI) kompozytów przy zastosowaniu kokonów i przeprowadzeniu in situ chemicznej utleniającej polimeryzacji. Wytworzone kompozyty zostały scharakteryzowane za pomocą skaningowego mikroskopu elektronowego (SEM), analizy termograwimetrycznej (TGA), spektrofotometrii w podczerwieni (IR) oraz elektronowego rezonansu spinowego (ESR). Potwierdzono, że otrzymane kompozyty, a następnie ich karbonizacja umożliwiły powstawanie mikroskopijnej wielkości płytek węglowych.

2

Electron spin resonance (ESR) spectra of butylated hydroxytoluene (BHT) as evidence of free radical formation in electrostatic discharge (ESD) damaged lubricating oils

Duchowski J. K.

Tribologia

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2014

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nr 4

43--52

EN

Electrostatic discharges were generated in typical ISO VG 46 cSt turbine lubricating oil by passing the oil through a glass fibre filter element at a hydraulic load of 0.06 L*min-1*cm-2. The oil exhibited electrical conductivity of 8 pS*m-1 at 25°C. The experiment was performed at room temperature. The maximum amplitude of ESD arcing events recorded was approximately –500 V. The magnitude of these arcing events was sufficient to generate a free radical formation of the BHT antioxidant additive generally employed as an antioxidant in typical turbine lubricating oil formulations. The free radical formation was evidenced by a clearly observable ESR signal corresponding to the BHT radical as recorded on an X-Band MiniScope MS100 spectrometer with a resonant frequency of 9.43 GHz and a maximum field sweep of 400 mT. These results indicate that ESD can well be responsible for initiating the free radical polymerization process postulated to result in varnish formation in turbine lubricating oils.

PL

Wyładowania elektrostatyczne zostały wygenerowane w typowym oleju ISO VG 46 cSt stosowanym jako olej smarny w turbinach gazowych w trakcie przepływu oleju przez element filtracyjny na bazie włókien szklanych przy obciążeniu hydraulicznym wynoszącym 0,06 L*min-1*cm-2. Przewodowość oleju wynosiła 8 pS*m-1 przy temperaturze 25°C. Eksperyment został przeprowadzony w temperaturze pokojowej. Maksymalna amplituda wyładowań elektrostatycznych osiągnęła –500 V. Amplituda wyładowań była wystarczająca, by doprowadzić do powstawania wolnych rodników BHT stosowanym jako antyutleniacz w typowych formulacjach turbinowych olejów smarnych. Obecność wolnego rodnika BHT została zarejestrowana za pomocą X-Band MiniScope MS100 spektrometru z częstotliwością rezonasową 9,43 GHz o maksymalnym zasięgu pola magnetycznego 400 mT. Zarejestrowane wyniki wskazują, że ESD może być źródłem powstawania wolnych rodników i prowadzić do wolnorodnikowych procesów polimeryzacyjnych odpowiedzialnych za tworzenie się zanieczyszczeń osadowych w turbinowych olejach smarnych.

3

Zastosowanie elektronowego rezonansu spinowego (ESR) do określania politypu kryształów SiC

Pawłowski M.

Materiały Elektroniczne

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2008

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T. 36, nr 1

70-86

PL

W pracy przedstawiono widma elektronowego rezonansu spinowego (ESR) dla atomów azotu występujących w różnych politypach monokryształów SiC. Określono wartości czynnika rozszczepienia spektroskopowego g oraz wartości parametru A, charakteryzującego wielkość rozszczepienia wywołanego oddziaływaniem nadsubtelnym. Przeprowadzono identyfikację politypu oraz oszacowano zawartość azotu. Stwierdzono możliwość określania politypu monokryształów SiC na podstawie pomiaru linii ESR dla atomów azotu.

EN

This work presents ESR spectra for nitrogen atoms in various polytypes of SiC crystals. The values of the spectroscopy splitting factor g, as well as of the parameter A describing the amount of splitting induced by hyperfine interaction were determined. The polytype identification was done and nitrogen content was estimated. The possibility of the SiC polytype identification on the grounds of nitrogen related ESR lines measurement was shown.

4

Magnetisation and Electron Spin Resonance of the colossal magnetoresistive La0.67Ca0.33Mn1-x FexO3

Zając T., Folcik L., Chmist J., Kołodziejczyk A., Drulis H., Krop K., Gritzner G.

Materials Science Poland

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2006

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Vol. 24, No. 3

795--801

EN

We report magnetisation and electron spin resonance (ESR) measurements on colossal magnetoresistive manganites La0.67Ca0.33Mn1-x FexO3 with x = 0, 0.01, 0.03, 0.06, 0.10 and 0.15 in the vicinity of the magnetic (TC) and metal- insulator (TMI) transition temperatures. Above TC the resonance lines with g?2 are caused by the ferromagnetic metallic clusters exhibiting the double exchange interaction between Mn3+-Mn4+ ions. The lines were observed with cooling far below both TC and TMI and were fitted by Dysonian line-shape. Temperature dependences of the linewidths exhibited a minimum value at Tmin?1.25 TC followed by an increase of the width with further cooling toward TC. The anomalous behaviour of the line-width below Tmin is due to an appearance of a ferromagnetic metallic phase within the paramagnetic matrix. The role of phase segregation in which the compounds are phase - separated into a mixture of ferromagnetic and paramagnetic regions is discussed.

5

Magnetic ordering processes in manganese(II) di(hydrogen malonate) dihydrate complex studied by ESR spectroscopy

Marczyński S., Typek J., Grech E., Kołodziej B.

Materials Science Poland

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2006

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Vol. 24, No. 4

1139--1144

EN

A new manganese complex of malonic acid CH2(COOH) 2źMnCO3źH2O was synthesized. Temperature dependence of the electron spin resonance (ESR) spectrum of Mn(II) was investigated in the 4.2-295 K. temperature range. The obtained ESR spectra were successfully fitted by using a Lorentzian-shape function. The fitting revealed existence of about 2% of a spurious phase of the manganese(II) complex. Strong magnetic interactions have been observed in the investigated temperature range with expected magnetic phase transition at TN approximately equals 2.5 K. The integrated intensity, linewidth and resonance field of the ESR spectrum have shown that the spin dynamical fluctuations essentially influence the magnetic system. An anomalous behaviour of the ESR resonance field parameter has been observed below 100 K. and with decreasing temperature the resonance field shifted to higher magnetic fields.

6

ESR study of spin dynamics in (Er0.5Y0.5)2Cu2O5 solid solution

Typek J., Guskos N.

Materials Science Poland

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2006

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Vol. 24, No. 4

901--912

EN

Powder samples of (Er0.5Y0.5)2Cu 2O5 have been synthesized by a solid state reaction method. Electron spin resonance (ESR) measurements have been carried out on a Broker E 500 X-band spectrometer in the 4-300 K temperature range. A single, almost Lorentzian-shaped resonance line has been recorded for the whole investigated temperature range and its ESR parameters (integrated intensity, linewidth and resonance field) displayed a strong temperature dependence. The integrated intensity of the resonance line showed a pronounced maximum in low-temperature range and vanished at the transition to the antiferromagnetic ordering at TN = 11 K. The temperature at which the ESR integrated intensity reaches its maximum is different for the heating and cooling runs. Below 40 K, on approach to TN, the linewidth exhibited a divergent behaviour due to the onset of three-dimensional magnetic order. At higher temperatures (about 220 K), variations in ESR magnetic susceptibility suggest the presence of dynamical processes in copper-oxygen chains leading to the formation of copper dirners. The observed changes of the ESR parameters are interpreted in terms of 2D magnetism of the copper-oxygen system in the (Er 0.5Y0.5)2Cu2O5 solid solution.

7

Electron spin resonance study of copper(II) hydrogenmalonate dihydrate complex

Marczyński S., Typek J., Guskos N., Grech E., Kołodziej B.

Materials Science Poland

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2006

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Vol. 24, No. 4

1077--1085

EN

Copper(II) hydrogenmalonate dihydrate complex has been studied by using the electron spin resonance (ESR) method. Numerically deconvoluted ESR spectra of Cu(II) ions have been investigated at 4.2-295 K temperature range. The powder ESR spectrum has been described by three g-factors and additionally 1.5% of the existing spurious phases of a copper(II) complex has been revealed. The temperature dependence of the integrated ESR intensity has shown a Curic-Weiss type behaviour, consisting of two terms with different Curie-Weiss temperatures. The observed ferromagnetic interactions suggest the presence of two different paramagnetic species. It is proposed that the [Cu(H2O) 4][Cu(mal)2(H2O)2] copper(II) dimer complex is responsible for the low-temperature (T less than or equal 50 K) behaviour of the investigated sample.

8

Effects of thermal treatment on magnetic properties of Ni2FeV3O11-.delta compound

Guskos N., Typek J., Żołnierkiewicz G., Błońska-Tabero A., Los S., Kempiński W.

Materials Science Poland

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2006

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Vol. 24, No. 4

983--990

EN

Ni2FeV3O11-.delat samples have been synthesized by the solid-state reaction method using two different heat treatment processes (samples of the type A and B). The XRD measurements have shown the same diffraction patterns for both types of samples. The temperature dependences of the electron paramagnetic resonance (EPR) spectra have been recorded for the two types of thermal annealing processes of Ni 2FeV3O11-.delta. Strong differences have been observed in the EPR spectra of both types of Ni2FeV3O 11-.delta. An intense EPR line has been recorded at high temperatures; it is suggested that the line is associated with oxygen-vanadium clusters (ferromagnetic ordering). The linewidth, resonance field and integrated intensity of the EPR spectra have shown a strong temperature dependence down to 200 K. Additionally, in one sample a very broad EPR line of Fe3+ ions appeared at low temperatures while at high temperatures this line was overlapped by the other line. The temperature dependence of the integrated intensity of this broad line has shown the Curie-Weiss behaviour. In the vanadate oxide materials with two strong magnetic ions in the structure (iron(III) and nickel(II)), the spectrum of the Fe3+ ions is not observed. Different oxygen deficiency processes could explain the differences in the EPR spectra of both types of Ni2FeV3O 11-.delta compounds.

9

PBT chain mobility from the ESR saturation spectra studies

Lembicz F.

Polimery

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2003

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T. 48, nr 7-8

557-564

EN

Temperature and microwave power dependence of ESR spectra of the spin probes in PBT has been studied. The observed changes of ESR signal allowed to determine the long correlation times (tau approximate to 10(-4)-10(-5) s) as well as other parameters characterizing the saturation processes and involved relaxation processes. It was established that at low temperature range (approximate to 120-200 K) the rotational mobility of used nitroxide radicals was related to local relaxation processes of the methylene sequences (3-4 CH2 groups) in an amorphous region of PBT. The obtained results show the possibility of that type of investigation also for other polymers. Determination of polymer properties via analysis of parameters obtained in saturation experiments is also raised.

PL

Zbadano zależność od temperatury oraz stosowanych mocy mikrofalowych widm ESR sondy spinowej (TEMPO) wprowadzonej do PBT. Rejestrowane zmiany sygnału ESR pozwoliły na wyznaczenie długich czasów korelacji (T~ 10 -10" s), a także innych parametrów charakteryzujących zjawiska nasy-ceniowe oraz związanie ich procesami relaksacyjnymi w PBT. Ustalono, że w niskiej temperaturze (120-200 K) ruchliwość rotacyjna użytych rodników nitroksylowych może być związana z lokalnymi procesami relaksacyjnymi. Wskazano na możliwość charakteryzowania właściwości polimerów w wyniku analizowania parametrów stosowanych głównie w badaniach nasyceniowych (rys. 2 i 3).

10

Radiation-induced paramagnetic centers in Bioglass(R).

Padlyak B., Szarska S., Jungner H.

Optica Applicata

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2000

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Vol. 30, nr 4

709-717

EN

The X-band (v=9.4 GHz) electron spin resonance (ESR) and thermally stimulated luminescence (TSL) spectra of the UV-, X-, and gamma -irradiated Bioglass(R) samples of different composition (Bioglass(R) I and Bioglass(R) II) have been investigated. The efficiency of generation of electron and hole centers strongly depends on basic Bioglass(R) composition and is almost independent of ionizing radiation type and presence of Fe/sup 3+/ non-controlled impurity in the glass network. The spin Hamiltonian parameters (g and a values) and thermal stability of the radiation-induced centers have been evaluated. The results of TSL measurements show good agreement with ESR data. The energetic structure, formation peculiarities and specific models of the radiation-induced paramagnetic centers in the Bioglass(R) network are discussed.

11

Morphology of sulfonated polyimide ionomers from ESR spectra of paramagnetic transition metal cations and nitroxide spin probes

Motyakin M. V., Cornet N., Gebel G., Schlick S.

Bulletin of the Polish Academy of Sciences. Chemistry

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2000

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Vol. 48, No. 4

273-292

EN

We present a study of sulfonated polyimide block ionomer membranes (SPIs) in the dry state, and swollen by water, methanol, ethanol, and dioxane. The ionomers are based on a naphthalenic dianhydride and differ in the ionic exchange capacity and the type of diamine in the hydrophobic block. The ionomers were studied by electron spin resonance (ESR) spectroscopy of the paramagnetic transition metal cations Cu "*" and VO "*", and of two nitroxide spin probes. The results indicated the existence of separate hydrophobic and hydrophilic domains in the dry and in the swollen membranes. Water clusters with a diameter < 40 A were detected in the water-swollen membranes, but the water has glassy properties and a much lower enthalpy of fusion compared to bulk water. No evidence for the presence of solvent clusters was obtained for the membranes swollen by methanol and ethanol. An ESR signal was observed in all neat SPI ionomers, and its intensity and line shape varied with ionomer structure and preparation method. The ESR intensity of this signal is higher in the membranes in acid form compared to membranes fully,.neutralized by Li* or K*. The irreversible increase of the signal intensity upon heating of the dry membranes above 360 K suggests the formation of reactive intermediates that may be involved in ionomer degradation processes.

12

Hydration and order in different aggregates of a poly(ethylene oxide) alkyl ether in aqueous solution. An ESR spin probe study

Caldararu H., Caragheorgheopol A., Schlick S.

Bulletin of the Polish Academy of Sciences. Chemistry

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2000

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Vol. 48, No. 4

367-383

EN

The local parameters (hydration, order, viscosity) in different aggregates (mi-celle, hexagonal and lamellar liquid crystals) in the phase diagram of poly(oxyethylene) [5]-dodecylether (C12E5) in water have been measured by EPR with two series of spin probes: x-DSA, (x == 5, 7, 10, 12 and 16) and CAT n (11. == 4, 8, 11 and 16). A rather complete map of hydration ([H20]/[Ea]) along the PEa chains has been determined. It shows that the hydration of the PEa regions is very low near the PEO/hydrocarbon interface in all phases a.nd increases towards the outer region of the PEO shell with a gradient which becomes steeper in micellar phase in comparison with the lamellar phase. Temperature increase reduces the hydration levels at all measured sites. The order of the chains decreases by dilution from the lamellar to the micellar phase, but it is preserved within the frame of the la,mellar pha.se a.t two different concentrations. The ol'der degree, 5, d.ecreases in the series .5- > 7- > 10- > 12- > 16-doxyl, irrespective of tern perature, in all t)'"pes of aggrega.tes. This trend, together with decreasing hydration values, points to the insertion of the stearic acid chain in the aggregates along the normal to the interface. In samples quenched in liquid nitrogen, however, bending of the stearic acid chain was observed in a number of cases.

13

ESR study of monolayer vanadium oxide catalysts supported of different supports in relation to catalytic oxidation of methanol

Haber J., Nowak P., Serwicka E. M., Wachs I. E.

Bulletin of the Polish Academy of Sciences. Chemistry

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2000

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Vol. 48, No. 4

337-346

EN

Vanadia monolayers deposited on various oxide supports (Zr02, Nb(2)O(5), TiO2, Al(2)O(3) and Si0(2) have been investigated with the aid of electron spin resonance. The results show that the electronic structure of reduced vanadyl species generated during methanol chemisorption depends on the nature of the supporting matrix. This is shown by changes of theBeta(2) bonding coefficient calculated from the experimentally determined ESR parameters. I t is demonstrated that the catalytic activity in methanol oxidation, ex-pressed in terms of turnover frequency (TOF), can be correlated with the latter parameter and increases with the ionicity of the vanadyl in-plane Pi-bonding system.