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排序方式: 共有244条查询结果,搜索用时 234 毫秒
121.
D. D. DiJulio J. Cederkall C. Fahlander A. Ekström P. Golubev K. Mattsson D. Rudolph G. de Angelis S. Aydin A. Y. Deo E. Farnea G. Farrelly K. Geibel C. He J. Iwanicki R. Kempley N. Marginean R. Menegazzo D. Mengoni R. Orlandi Z. Podolyak F. Recchia P. Reiter E. Sahin J. Smith P. A. Söderström D. A. Torres G. M. Tveten C. A. Ur J. J. Valiente-Dobón A. Wendt M. Zielińska 《The European Physical Journal A - Hadrons and Nuclei》2011,47(2):1-7
122.
Layiq Zia G. Hassnain Jaffari Jamil Ur Rahman Soonil Lee S. Ismat Shah 《Physics letters. A》2019,383(26):125835
The effect of thermal quenching on physical properties of morphotropic phase boundary BiFeO3-0.35PbTiO3 composition, composed of Pnma, R3c and P4mm phases, has been investigated in detail. We detected and quantified role of quenching through investigation of magnetic, dielectric and ferroelectric anomalies. Quenching significantly i) enhances the tetragonal phase percentage (hence affects domain structure), ii) reduces domain wall clamping with a large increase in electrical polarization, iii) increases magnetization at the structural phase transition temperature (tunable magneto-electric coupling), iv) magnifies intrinsic property i.e. intra grain relaxation dynamics (which are otherwise suppressed due to the pinning of the defect dipoles), etc. All these findings clearly verify the role of quenching which noticeably enhances multiferroic properties at the well-known morphotropic phase boundary. 相似文献
123.
Umair Manzoor Mohammad Islam Lubna Tabassam Shams Ur Rahman 《Physica E: Low-dimensional Systems and Nanostructures》2009,41(9):1669-1672
Quantum mechanical effects such as an increased bandgap of semiconductors with reduction of size are viewed as having strong potential for future applications. In the present work, zinc oxide (ZnO) nanoparticles (NPs) were synthesized via the co-precipitate method. Very narrow particle size distribution of the ZnO nanoparticles was achieved through careful control of the synthesis conditions. The structural, morphological, and optical characterization was carried out using X-ray diffraction, atomic force microscopy, and UV–vis reflectance techniques, respectively. The results indicated that increasing the temperature from 60 to 65 °C caused a subsequent increase in particle size from 4 to 12 nm. An associated increase in bandgap with decrease in particle size was also noticed which is a strong indication of the quantum confinement effect. 相似文献
124.
Quantum spin Hall and quantum valley Hall effects in trilayer graphene and their topological structures
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The present study pertains to the trilayer graphene in the presence of spin orbit coupling to probe the quantum spin/valley Hall effect. The spin Chern-number C_s for energy-bands of trilayer graphene having the essence of intrinsic spin–orbit coupling is analytically calculated. We find that for each valley and spin, C_s is three times larger in trilayer graphene as compared to single layer graphene. Since the spin Chern-number corresponds to the number of edge states,consequently the trilayer graphene has edge states, three times more in comparison to single layer graphene. We also study the trilayer graphene in the presence of both electric-field and intrinsic spin–orbit coupling and investigate that the trilayer graphene goes through a phase transition from a quantum spin Hall state to a quantum valley Hall state when the strength of the electric field exceeds the intrinsic spin coupling strength. The robustness of the associated topological bulk-state of the trilayer graphene is evaluated by adding various perturbations such as Rashba spin–orbit(RSO) interaction αR, and exchange-magnetization M. In addition, we consider a theoretical model, where only one of the outer layers in trilayer graphene has the essence of intrinsic spin–orbit coupling, while the other two layers have zero intrinsic spin–orbit coupling.Although the first Chern number is non-zero for individual valleys of trilayer graphene in this model, however, we find that the system cannot be regarded as a topological insulator because the system as a whole is not gaped. 相似文献
125.
N. H. Medina F. Brandolini S. M. Lenzi N. Mărginean R. V. Ribas C. A. Ur D. Bazzacco S. Lunardi R. Menegazzo P. Pavan C. Rossi-Alvarez A. Algora-Pineda G. de Angelis M. De Poli E. Farnea A. Gadea T. Martinez D. R. Napoli S. Hankonen D. Bucurescu M. Ionescu-Bujor A. Iordachescu J. A. Cameron S. Kasemann I. Schneider J. M. Espino J. Sanchez-Solano A. Poves 《Acta Physica Hungarica A》2002,16(1-4):65-74
Lifetimes have been determined using the Doppler Shift Attenuation Method in the N ≈ Z nuclei 46V and 48V, populated with the reaction 28Si on 24Mg at 115 MeV and 24Mg on 28Si at 100 MeV using Au and Pb backed targets. The coexistence of spherical and deformed states in the middle of the 1f7/2 shell is discussed. The B(E2) and B(M1) reduced rates agree very well with large scale shell model predictions. 相似文献
126.
Lenzi SM Mărginean N Napoli DR Ur CA Zuker AP de Angelis G Algora A Axiotis M Bazzacco D Belcari N Bentley MA Bizzeti PG Bizzeti-Sona A Brandolini F von Brentano P Bucurescu D Cameron JA Chandler C De Poli M Dewald A Eberth H Farnea E Gadea A Garces-Narro J Gelletly W Grawe H Isocrate R Joss DT Kalfas CA Klug T Lampman T Lunardi S Martínez T Martínez-Pinedo G Menegazzo R Nyberg J Podolyak Z Poves A Ribas RV Rossi Alvarez C Rubio B Sánchez-Solano J Spolaore P Steinhardt T Thelen O Tonev D 《Physical review letters》2001,87(12):122501
Gamma rays from the N = Z-2 nucleus (50)Fe have been observed, establishing the rotational ground state band up to the state J(pi) = 11+ at 6.994 MeV excitation energy. The experimental Coulomb energy differences, obtained by comparison with the isobaric analog states in its mirror (50)Cr, confirm the qualitative interpretation of the backbending patterns in terms of successive alignments of proton and neutron pairs. A quantitative agreement with experiment has been achieved by exact shell model calculations, incorporating the differences in radii along the yrast bands, and properly renormalizing the Coulomb matrix elements in the pf model space. 相似文献
127.
A. Dewald O. Möller D. Tonev A. Fitzler B. Saha K. Jessen S. Heinze A. Linnemann J. Jolie K. O. Zell P. von Brentano P. Petkov R. F. Casten M. Caprio J. R. Cooper R. Krücken V. Zamfir D. Bazzacco S. Lunardi C. Rossi-Alvarez F. Brandolini C. Ur G. De Angelis D. R. Napoli E. Farnea N. Marginean T. Martinez M. Axiotis 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):173-178
Reliable and precise lifetimes of excited states in 154Gd and 156Dy were measured using the recoil distance Doppler shift (RDDS) technique. Excited states of 154Gd were populated via Coulomb excitation with a 32S beam at 110 MeV delivered by the FN tandem accelerator at the University of Cologne. For 156Dy a coincidence plunger experiment was performed at the Laboratori Nazionali di Legnaro with the GASP spectrometer and the Cologne coincidence plunger apparatus using the reaction 124Sn(36S,4n)156Dy at a beam energy of 155 MeV. Shape changes previously suggested to appear in the ground-state band (gsb) of 156Dy and in the s-band above the first band crossing were not supported by the transition probabilities determined in this work. The measured transition probabilities of 156Dy and 154Gd as well as the corresponding energy spectra are compared with the predictions of the recently proposed X(5) model and in the case of 156Dy also with an IBA fit.Received: 30 October 2002, Published online: 2 March 2004PACS:
21.10.Tg Lifetimes - 27.70. + q
- 21.60.Ev Collective models - 23.20.-g Electromagnetic transitions 相似文献
128.
J. Wrzesiński R. Broda B. Fornal W. Królas T. Pawłat M. P. Carpenter R. V. F. Janssens D. Seweryniak S. Lunardi C. A. Ur G. Viesti M. Cinausero N. Marginean K. H. Maier 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):57-58
New high-spin states were identified in the 205Tl isotope produced in deep-inelastic heavy-ion reactions. The expected 29/2 + yrast state and 35/2- isomeric state with 235 ns half-life were located above the 2.6 s isomer known from previous studies. Above this isomer a 7092 keV level was interpreted as a 41/2 + state arising from the coupling of the octupole vibration of the 208Pb core with the three-hole structure of the 35/2- isomer.Received: 20 January 2003, Revised: 10 March 2003, Published online: 2 March 2004PACS:
21.60.Cs Shell model - 23.20.Lv Gamma transitions and level energies - 27.80. + w
- 25.70.Lm Strongly damped collisions 相似文献
129.
An elementary notion of master-slave synchronization that accepts multimodal synchronization is introduced. We prove rigorously that the attractor of a coupled pair in a regime of multimodal synchronization is the graph of a multivalued function. Our framework provides the theoretical basis for some practical tools for detection of multimodal synchrony in experiments. Results are illustrated with the analysis of experiments with coupled electronic oscillators. 相似文献
130.
Diana?Uría Fernández Valérie?Geoffroy Mathias?Sch?fer Jean-Marie?Meyer Herbert?BudzikiewiczEmail author 《Monatshefte für Chemie / Chemical Monthly》2003,134(10):1421-1431
Summary. The structural revision on the basis of spectroscopic and degradation results of several pyoverdins from Pseudomonas spp. is reported. Siderotyping studies by the isoelectrofocusing technique and by ferri-pyoverdin uptake experiments had prompted a re-investigation of some structures proposed in the literature.Received June 26, 2003; accepted July 7, 2003
Published online September 11,2003 相似文献