Search results for "magnetic [charge]"
showing 10 items of 6136 documents
Aggregation of [Ln(12)(III)] clusters by the dianion of 3-formylsalicylic acid. Synthesis, crystal structures, magnetic and luminescence properties
2019
Three isostrucutral dodecanuclear clusters with the general formula [Ln(12)(fsa)(12)(mu f(3)-OH)(12)(DMF)(12)]center dot nDMF (fsa(2-) is the dianion of 3-formylsalicylic acid; Ln = Eu 1, Gd 2, Dy 3) have been obtained from the reaction of fromylsalicyclic acid (H(2)fsa), tetrabutylammonium hydroxide and Ln(NO3)(3)center dot 6H(2)O in methanol/DMF. Their structure consists of four vertex-sharing heterocubanes. Each heterocubane unit is assembled from four Ln(III) ions, three mu(3)-OH groups and one mu(3)-oxygen atom arising from the fsa(2-) carboxylato group. The photophysical properties of the europium derivative investigated at both 300 and 80 K sustain a relative intense emission obtaine…
Color Sensitive Response of Graphene/Graphene Quantum Dot Phototransistors
2019
We present the fabrication and characterization of all-carbon phototransistors made of graphene three terminal devices, coated with atomically precise graphene quantum dots (GQD). Chemically synthesized GQDs are the light absorbing materials, while the underlying chemical vapor deposition (CVD)-grown graphene layer acts as the charge transporting channel. We investigated three types of GQDs with different sizes and edge structures, having distinct and characteristic optical absorption in the UV–vis range. The photoresponsivity exceeds 106 A/W for vanishingly small incident power (<10–12 W), comparing well with state of the art sensitized graphene photodetectors. More importantly, the photor…
Energy transfer in LH2 of Rhodospirillum Molischianum, studied by subpicosecond spectroscopy and configuration interaction exciton calculations.
2001
Two color transient absorption measurements were performed on a LH2 complex from Rhodospirillum molischianum by using several excitation wavelengths (790, 800, 810, and 830 nm) and probing in the spectral region from 790 to 870 nm at room temperature. The observed energy transfer time of ∼1.0 ps from B800 to B850 at room temperature is longer than the corresponding rates in Rhodopseudomonas acidophila and Rhodobacter sphaeroides. We observed variations (0.9-1.2 ps) of B800-850 energy transfer times at different B800 excitation wavelengths, the fastest time (0.9 ps) was obtained with 800 nm excitation. At 830 nm excitation the energy transfer to the B850 ring takes place within 0.5 ps. The m…
Modeling Stator Winding Inter-Turn Short Circuit Faults in PMSMs including Cross Effects
2020
Author's accepted manuscript. © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This paper presents a detailed analysis of stator winding inter-turn Short Circuit (ITSC) faults, taking the cross effects in the three phases of a permanent magnet synchronous motor (PMSM) into account by considering insulation degradation resistances. A PMSM with series coils in eac…
A General Mathematical Formulation for the Determination of Differential Leakage Factors in Electrical Machines with Symmetrical and Asymmetrical Ful…
2018
This paper presents a simple and general mathematical formulation for the determination of the differential leakage factor for both symmetrical and asymmetrical full and dead-coil windings of electrical machines. The method can be applied to all multiphase windings and considers Gorges polygons in conjunction with masses geometry in order to find an easy and affordable way to compute the differential leakage factor, avoiding the adoption of traditional methods that refer to the Ossanna's infinite series, which has to be obviously truncated under the bound of a predetermined accuracy. Moreover, the method described in this paper allows the easy determination of both the minimum and maximum v…
Determination of differential leakage factors in electrical machines with non-symmetrical full and dead-coil windings
2017
In this paper Gorges polygons are used in conjunction with masses geometry to find an easy and affordable way to compute the differential leakage factor of non symmetrical full and dead coil winding. By following the traditional way, the use of the Ossanna's infinite series which has to be obviously truncated under the bound of a predetermined accuracy is mandatory. In the presented method no infinite series is instead required. An example is then shown and discussed to demonstrate practically the effectiveness of the proposed method.
Magnetic domain structure of La0.7Sr0.3MnO 3 thin-films probed at variable temperature with scanning electron microscopy with polarization analysis
2013
The domain configuration of 50 nm thick La0.7Sr0.3MnO3 films has been directly investigated using scanning electron microscopy with polarization analysis (SEMPA), with magnetic contrast obtained without the requirement for prior surface preparation. The large scale domain structure reflects a primarily four-fold anisotropy, with a small uniaxial component, consistent with magneto-optic Kerr effect measurements. We also determine the domain transition profile and find it to be in agreement with previous estimates of the domain wall width in this material. The temperature dependence of the image contrast is investigated and compared to superconducting-quantum interference device magnetometry …
Large Zero-Field Cooled Exchange-Bias in BulkMn2PtGa
2013
We report a large exchange-bias (EB) effect after zero-field cooling the new tetragonal Heusler compound Mn2PtGa from the paramagnetic state. The first-principle calculation and the magnetic measurements reveal that Mn2PtGa orders ferrimagnetically with some ferromagnetic (FM) inclusions. We show that ferrimagnetic (FI) ordering is essential to isothermally induce the exchange anisotropy needed for the zero-field cooled (ZFC) EB during the virgin magnetization process. The complex magnetic behavior at low temperatures is characterized by the coexistence of a field induced irreversible magnetic behavior and a spin-glass-like phase. The field induced irreversibility originates from an unusual…
Optical properties of GaSe, characterization and simulation
2021
Abstract The study focuses on structural and optical characterizations and properties of the GaSe lamellar material in one hand and on a numerical simulation of the photovoltaic properties of the ITO/GaSe heterojunction in a second hand. A few layers of GaSe were exfoliated from bulk GaSe on PET substrate. The optical transmission was recorded at room temperature. It shows that GaSe exhibits both indirect and direct band gaps of about 1.92 and 2.2 eV respectively. A value, as high as 104 cm−1, of the absorption coefficient was obtained. The corresponding refractive index has been determined numerically according to the Sellmeier and Cauchy models. The interesting value of absorption shows o…
X-ray diffraction and Raman spectroscopy studies in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 solid solutions
2016
The long and short range orders in 0.4Na1/2Bi1/2TiO3-(0.6-x)SrTiO3-xPbTiO3 solid solutions were studied by x-ray diffraction and Raman spectroscopy. X-ray diffraction patterns for these composition...