55,250 research outputs found
New resonant behavior in the spin resolved photoionization of the rare gas atoms Kr 3d and Xe 4p
No full textKhalil T. New resonant behavior in the spin resolved photoionization of the rare gas atoms Kr 3d and Xe 4p. Bielefeld (Germany): Bielefeld University; 2002.In the first part of this thesis, the transferred spin polarization of resonantly excited Auger electrons of Kr 3d-1 5p photoionized by circularly polarized light was measured. The transferred spin polarization is related to the orientation A10 (and alignment A20) of core holes induced by the primary photoionization process, and to the intrinsic parameters [xi]1 which characterizes the transferred spin polarization of Auger electrons and [alpha]2, the anisotropy parameter which characterizes the angular intensity distribution of Auger electrons. Due to the selection rules of dipole excitation of Kr 3d-1 5p atoms i.e. Ji=1, A10 and A20 are known, [alpha]2 was calculated and measured by Kitajima et al. The calculation of [xi]1 was performed by N. M. Kabachnik and S. Fritzsche.
In the second part of this thesis, the spin polarization of Xe 4p near the ionization threshold was measured to examine the calculations of Cherepkov of contribution of the lowest order nondipole term; the electric-dipole-electric-quadrupole interference terms to the spin polarization of Xe np photoelectrons. The quadrupol matrix elements of the np->[epsilon]f transitions in Xe calculated in RPAE have strong maxima near the ionization threshold. This behaviour is similar to the well-known maxima in the dipole nd->[epsilon]f transitions. These dipole nd->[epsilon]f transitions are responsible for the so-called giant resonances in the total photoionization cross section. They are attributed to the double-well shape of the effective potential for the dipole [epsilon]f partial waves. Both the RPAE non-relativistic calculation from Cherepkov and the relativistic IPA adapted calculation from Derevianko agree qualitatively with the measured nondipole component of electron spin polarization
Surface treatment of Ti-6Al-4V alloy by rf plasma nitriding
No full textThe Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N(2) gas was introduced to establish a treatment pressure of 8.0-8.4 x 10(-2) mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma- processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 mu m(2) s(-1) at a plasma-processing time of 25 min was achieved. The formation of the hard phases TiN, Ti(2)N, and Ti( N) in the Ti-6Al-4V surfaces are found to be the reason for the increased microhardness. Surface energy, yield strength and Young's modulus for the nitrided Ti-6Al-4V alloy were calculated from the Vickers microhardness data
Role of Sumac (Rhus coriaria L.) in the management of metabolic syndrome and related disorders: Focus on NAFLD-atherosclerosis interplay
No full textSumac (Rhus coriaria L.) is a commonly used spice in the Mediterranean region and considered as healthy food ingredients. The beneficial value of sumac is well documented in folk medicine. Accumulating data explored the phytochemical, nutritional and therapeutic proprieties suggesting sumac as a potential functional food. Here, we discuss the general and scientific aspects of sumac. Sumac is rich in different polyphenolic compounds such as flavonoids, tannins, and phenolic acids. The potential therapeutic effects of sumac have been studied in various cellular and animal models, as well as in human. These reports suggest that Sumac has potential effect against oxidative stress, inflammation, obesity, hyperglycemia, hypercholesterolemia, and hyperlipidemia, which represent key pathogenic mechanisms contributing to cardio-metabolic, liver, and cancer diseases. Clinical studies using sumac or its major compounds, suggest that this herbal product may represent a useful therapeutic tool in the management of metabolic-related conditions such as liver-atherosclerosis complications
Influence of rf-power on the plasma carbonitriding of titanium
No full textThe present work reports on the effect of input plasma processing power in the range of 350-650W on the microstructure and mechanical properties of plasma nitrided Ti. The plasma processing time was 20 min and a gas mixture of 15% C2H2 and 85% N-2 was used. The characteristics of the carbonitrided layer have been investigated by microhardness measurements, surface roughness measurements, optical microscopy, and X-ray diffraction. The measured surface hardness values of the compound layer shows a maximum of 2050 HV0.1 for the sample treated at a plasma power of 550W. The thickness of the carbonitrided layer continuously increases as the plasma power increases. Moreover, the highest carbonitriding rate of 3.52 mu m(2)/s was observed when the input plasma power was adjusted at 600 W. This high carbonitriding rate of treated titanium samples is ascribed to the high concentration of active carbon and nitrogen species in the plasma atmosphere and the formed microcracks in the near surface of the sample during the plasma processing. (C) 2007 Elsevier B.V. All rights reserved
Some Fixed Point Theorems in Fuzzy n-Normed Spaces
No full textThe main purpose of this paper is to study the existence of a fixed points in fuzzy n-normed spaces. we proved our main results, a fixed point theorem for a self mapping and a common fixed point theorem for a pair of weakly compatible mappings on fuzzy n-normed spaces. Also we gave some remarks on fuzzy n-normed spaces
Complete characterization of the atomic Auger decay
No full textDrescher M, Schmidtke B, Khalil T, Müller N, Heinzmann U. Complete characterization of the atomic Auger decay. BESSY Highlights. 2002;2001:30-30
Informetrics on M. N. Srinivas
No full textM. N. Srinivas, the well known sociologist is widely recognised as architect of modern Indian sociology and social anthropology. His publications have been analysed by year, domain, authorship pattern, channels of communication used. Keywords, etc. The results indicate that the papers published by him are of a nature that qualify him to be a 'role model' for the younger generations to emulate.
By the end of 1995, Srinivas had to his credit 144 papers which, included 33 broad papers in sociology and anthropology; 18 papers in social change; 28 papers in village studies; 12 papers on religion; 17 papers on caste and 36 papers of general popular interest. The periods 1958-61 and 1974-77, when Srinivas was 38-41 and 58-61 years old. were his most productive periods with highest publication activity
Photochemistry of some cyclopentadienyl carbonyl complexes of chromium, molybdenum, tungsten, iron and ruthenium isolated in frozen gas matrices at 12K
No full textPhotochemical processes of a variety of cyclopentadienyl transition metal carbonyl complexes of general formula (η5-C5H5)M(CO)nR(n = 3, M = Cr, Mo, W; n = 2, M = Fe, Ru; R = alkyl), (η5-C5H5)M(CO)nX (n = 3, M = Mo, W; X = Cl, AsR2, SbR2; n = 2, M = Fe, Ru: X = Cl) and (η5-C5H5)2Fe2(CO)4have been studied for the first time at 12K using primarily infrared spectroscopy together with 13CO labelling.Photoejection of CO from (η5-C5H5)M(CO)3R complexes (M = Cr, Mo, W; R = CH3, CF3, COCF3) results in the formation of the 16-electron species (η5-C5H5)M(CO)2R. Evidence is also found for α-H and α-F elimination in the complexes (η5-C5H5)Cr(CO)3CH3 and (η5-C5H5)Mo(CO)3CF3 respectively, and for the fluoroalkyl migration to the metal in the complex (η5-C5H5)Mo(CO)3COCF3.Photolysis of (η5-C5H5)M(CO)3H complexes (M = Cr, Mo, W) in Ar and CH4 matrices generates the16-electron species (η5-C5H5)M(CO)2H. The reactivity of these species is apparent in their reactions with N2and C2H4 to produce (η5-C5H5)M(CO)2(N2)H and (η5-C5H5)M(CO)2(C2H4)H derivatives. In CO matrices the observation of the radicals (η5-C5H5)M(CO)3͘ and HCȮ is indicative of photo-induced metal-hydrogen bond cleavage. Irradiation of trans-(η5-C5H5) W(C0)2(C2H4)H in CH4 matrices causes trans ⇌ cis isomerisation, followed by insertion of C2H4 into the W-H bond to generate the 16-electron species (η5-C5H5)W(CO)2C2H5.Irradiation of (η5-C5R5̍)M(CO)3 alkyl complexes (M = Mo, W; R' = H, CH3) results in the formation of the 16-electron intermediates (η5-C5R5̍)M(CO)2alkyl. For alkyl complexes with β-hydrogens, thermal and photochemical 6-elimination reactions led to the conversion of (η5-C5R5̍)M(CO)2 alkyl species into the olefin-hydrides (η5-C5R5̍)M(CO)2(olefin)H. Photolysis of the (η5-C5H5)W(CO)3(η1-R) complexes (R = C3H5, CH2C6H5), led to CO dissociation and η1 ⇌ η3 isomerisation.Direct evidence for CO dissociation as a primary photoprocess for (η5-C5H5)M(CO)2R complexes (M = Fe, Ru; R = CH3, C5H5) was afforded by trapping the 16-electron species (η5-C5H5)Ru(CO)CH3 in a CH4 matrix. Photolysis of (η5-C5H5)M(CO)2C2H5 complexes in CH4 matrices afforded (η5-C5H5)Fe(CO)2H and (η5-C5H5)Ru(CO)2H together with(η5-C5H5)Ru(CO)(C2H4)H, i.e. β-elimination. In CO matrices ring-slippage products, (η3-C5H5)M(CO)3R, were formed.</p
The influence of rf plasma time on the carbonitriding treatment of titanium
No full textInductively coupled radio frequency plasma surface treatment was applied to commercially pure titanium sheets. The goal was to increase the efficiency of the carbonitriding process, i.e., to decrease the plasma treatment time to a few tens of minutes instead of several hours. The effects of different plasma-processing times on the microstructure and mechanical properties of plasma-carbonitrided Ti were examined. The characteristics of the carbonitrided layer were investigated by microhardness testing, surface roughness measurements, optical microscopy and X-ray diffraction. The surface microhardness and the thickness of the compound layer of carbonitrided Ti increase with the plasma-processing time. Surface energy, yield strength and Young's modulus for carbonitrided titanium were calculated from the Vickers microhardness data. An attempt was made to interpret the high carbonitriding rate and the high microhardness values of carbonitrided titanium with respect to previously published results
Spin polarization transfer in the resonant Auger decay following Kr 3d(-1)5p photoexcitation
No full textDrescher M, Khalil T, Müller N, Fritzsche S, Kabachnik NM, Heinzmann U. Spin polarization transfer in the resonant Auger decay following Kr 3d(-1)5p photoexcitation. JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 2003;36(15):3337-3347.Spin polarization of the resonant Auger electrons is measured following the decay of Kr 3d(-1)5p states resonantly excited by circularly polarized light. A large polarization transfer is found in particular for all strong transitions to the 4s(-1)4p(-1)5p and 4s(-2)5p states. The experimental results are in excellent agreement with calculations carried out by means of the multiconfiguration Dirac-Fock method
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