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1.
Gabriela Ionita Petre Ionita Victor EM. Sahini Constantin Luca 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):269-271
The kinetics of oxidation of amino acids (Arg, His, Lys, Phe, Thr and Tyr), a dipeptide (Gly-His), and BSA (bovine serum albumin) by two persistent water soluble free radicals of the hydrazyl type has been studied.The rate decreases in the order Arg>Lys>Tyr>Thr>HisBSAPheGly-His with bothfree radicals. Addition to the reaction mixture of - and -cyclodextrin decreases the oxidation rate, probably due to amino acidencapsulation in the cyclodextrin cavity. -Cyclodextrin protects more efficiently against oxidation than -cyclodextrin. 相似文献
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We have used a variety of microscopic techniques to reveal the structure and motion of flux line arrangements, when the flux
lines in low T
c type II superconductors are caused to move by a transport current. Using small-angle neutron scattering by the flux line
lattice (FLL), we are able to demonstrate directly the alignment by motion of the nearest-neighbor FLL direction. This tends
to be parallel to the direction of flux line motion, as had been suspected from two-dimensional simulations. We also see the
destruction of the ordered FLL by plastic flow and the bending of flux lines. Another technique that our collaboration has
employed is the direct measurement of flux line motion, using the ultra-high-resolution spectroscopy of the neutron spin-echo
technique to observe the energy change of neutrons diffracted by moving flux lines. The muon spin rotation (μSR) technique gives the distribution of values of magnetic field within the FLL. We have recently succeeded in performing
μSR measurements while the FLL is moving. Such measurements give complementary information about the local speed and orientation
of the FLL motion. We conclude by discussing the possible application of this technique to thin film superconductors. 相似文献
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KM Clauwaert Van Bocxlaer JF HJ Major JA Claereboudt WE Lambert Van den Eeckhout EM Van Peteghem CH De Leenheer AP 《Rapid communications in mass spectrometry : RCM》1999,13(14):1540-1545
This paper describes the investigation of the potential of a quadrupole orthogonal acceleration time-of-flight mass spectrometer (Q-TOF) equipped with an atmospheric pressure ionisation interface for quantitative measurements of small molecules separated by reversed phase liquid chromatography. To this end, the detection limits and linear dynamic range in particular were studied in an LC/MS/MS experiment using 3,4-methylenedioxymethamphetamine standards and 3,4-methylenedioxyethylamphetamine for internal standardisation. In a second phase, the experiment was repeated with real biological extracts (whole blood, serum, and vitreous humour). A calibration for 3,4-methylenedioxymethamphetamine and its metabolite 3,4-methylenedioxyamphetamine was prepared in each of these matrices again using 3,4-methylenedioxyethylamphetamine as internal standard. The resulting quantitative data were compared with those obtained by liquid chromatography with fluorescence detection for the same extracts. The Q-TOF results revealed excellent sensitivity and a linear dynamic range of nearly four decades (2-10 000 pg on-column, r(2) = 0.9998, 1/x weighting). Furthermore, all the calibration curves prepared in biological material were superimposable, LC/MS/MS and LC-fluorescence, and the quantitative results for actual samples compared very favourably. It was concluded that the Q-TOF achieves a linear dynamic range for quantitative LC/MS/MS work exceeding that of fluorescence detection and at much better absolute sensitivity. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
6.
N. A. Davidenko S. V. Dekhtyarenko A. V. Kozinets A. S. Lobach E. V. Mokrinskaya V. A. Skryshevsky N. G. Spitsyna S. L. Studzinsky O. V. Tretyak L. S. Tonkopieva 《Technical Physics》2011,56(2):259-263
The subject of investigation is poly-N-epoxypropylcarbazole and poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene-vinylene] films with zinc 2,3,9,10,16,17,23,24-octabutylphthalocyanine
additives. The photoconducive and photodielectric properties of these heterostructures are studied in the absorption range
of the metal complex. The photosensitivity of the structures depends on the triplet state of photogenerated electron-hole
pairs, their dissociation in an external electric field, and charge carrier trapping. The increased photosensitivity of the
heterostructures compared with that of constituent films is explained by a higher efficiency of dissociation of the photogenerated
electron-hole pairs and a reduced influence of non-equilibrium carrier traps at the interfaces. 相似文献
7.
EM Kozinets O Koniev OA Filippov JC Daran R Poli ES Shubina NV Belkova E Manoury 《Dalton transactions (Cambridge, England : 2003)》2012,41(38):11849-11859
Complexes [RhCl(diene)(P,SR)] with chiral ferrocenyl phosphine-thioethers ligands (diene = norbornadiene, NBD, 1(R), or 1,5-cyclooctadiene, COD, 3(R); P,SR = CpFe(1,2-η(5)-C(5)H(3)(PPh(2))(CH(2)SR); R = tBu, Ph, Bz, Et) and the corresponding [Rh(diene)(P,SR)][BF(4)] (diene = NBD, 2(R); COD, 4(R)) have been synthesized from [RhCl(diene)](2) and the appropriate P,SR ligand. The molecular structure of the cationic complexes 2(tBu), 4(Ph) and 4(Bz), determined by single-crystal X-ray diffraction, shows the expected slightly distorted square planar geometry. For the neutral chloride complexes, a combination of experimental IR and computational DFT investigations points to an equally four coordinate square planar geometry with the diene ligand, the chlorine and the phosphorus atoms in the coordination sphere and with a dangling thioether function. However, a second isomeric form featuring a 5-coordinated square planar geometry with the thioether function placed in the axial position is easily accessible in some cases. 相似文献
8.
N. A. Davidenko A. A. Ishchenko A. V. Kozinets L. I. Kostenko I. V. Kurdyukova E. V. Mokrinskaya S. L. Studzinskii N. G. Chuprina 《Journal of Applied Spectroscopy》2011,78(1):129-133
We have studied the photoconducting properties of films of ferrocene-containing oligomer with additives of squarylium and
merocyanine dyes based on ferrocene and tetranitrofluorene in the dye absorption region. We have studied the characteristic
features of the effect of an external magnetic field on the photocurrents. After the magnetic field is turned on, the photocurrent
increases in the samples with squarylium dye and decreases in the samples with merocyanine dye. We discuss the hypothesis
that in the first case, as a result of an internal photoelectric effect, predominantly triplet charge pairs are formed, while
in the second case predominantly singlet charge pairs are formed. The latter may be one of the reasons for the higher photoconductivity
of films with squarylium dye compared with merocyanine dye. 相似文献
9.
E. M. Kozinets G. A. Silantyev N. V. Belkova E. S. Shubina R. Poli E. Manoury 《Russian Chemical Bulletin》2013,62(3):751-757
Rhodium complexes with the planar chiral phosphinoferrocenyl thioether ligands [Rh(P,SR)(diene)X] (R = Me, But, Ph, Bn, diene is cyclooctadiene (COD) or norbornadiene (NBD), X = Cl, BF4) catalyze hydrogenation of ketones, imines, and heteroaromatic compounds; in the case of acetophenone, the enantioselectivity reached 60% ee. Similar iridium complexes demonstrate a good activity in the hydrogenation of imines, the maximal enantioselectivity in the case of N-phenyl-N-(1-phenylethylidene)amine was about 40% ee. 相似文献
10.
N. A. Davidenko S. V. Dekhtyarenko V. N. Kokozei A. V. Kozinets V. G. Makhan’kova V. A. Skryshevskii S. L. Studzinskii O. V. Tretyak E. N. Chigorin 《High Energy Chemistry》2010,44(5):423-425
The specific features of electric conductivity and photoconductivity in films of composites based on poly(vinyl alcohol) doped
with the complex [Fe(bipy)3][Zn(NCS)4] (where bipy is 2,2′-bipyridyl) and the effect of magnetic field on these properties were studied. It was found that photocurrent
decreases with an increase in the magnetic field strength up to 5.5 kOe. It was assumed that the photoconductivity of these
composites and its dependence on magnetic field are affected by paramagnetic iron(III) complex particles produced as a result
of internal photoelectric effect. The effect of magnetic field on the photoconductivity is associated with the spin-dependent
recombination of photogenerated charge pairs. 相似文献