Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Reversible mechanical and electrical properties of ripped graphene  [PDF]
J. Henry Hinnefeld,Stephen T. Gill,Shuze Zhu,William J. Swanson,Teng Li,Nadya Mason
Physics , 2014, DOI: 10.1103/PhysRevApplied.3.014010
Abstract: We examine the mechanical properties of graphene devices stretched on flexible elastomer substrates. Using atomic force microscopy, transport measurements, and mechanics simulations, we show that micro-rips form in the graphene during the initial application of tensile strain; however subsequent applications of the same tensile strain elastically open and close the existing rips. Correspondingly, while the initial tensile strain degrades the devices' transport properties, subsequent strain-relaxation cycles affect transport only moderately, and in a largely reversible fashion, yielding robust electrical transport even after partial mechanical failure.
Electrical annealing of severely deformed copper: microstructure and hardness  [PDF]
Saeed Nobakht,Mohsen Kazeminezhad
- , 2017, DOI: https://doi.org/10.1007/s12613-017-1506-2
Abstract: Commercial pure copper sheets were severely deformed after primary annealing to a strain magnitude of 2.32 through constrained groove pressing. After induction of an electrical current, the sheets were heated for 0.5, 1, 2, or 3 s up to maximum temperatures of 150, 200, 250, or 300°C. To compare the annealing process in the current-carrying system with that in the current-free system, four other samples were heated to 300°C at holding times of 60, 90, 120, or 150 s in a salt bath. The microstructural evolution and hardness values of the samples were then investigated. The results generally indicated that induction of an electrical current could accelerate the recrystallization process by decreasing the thermodynamic barriers for nucleation. In other words, the current effect, in addition to the thermal effect, enhanced the diffusion rate and dislocation climb velocity. During the primary stages of recrystallization, the grown nuclei of electrically annealed samples showed greater numbers and a more homogeneous distribution than those of the samples annealed in the salt bath. In the fully recrystallized condition, the grain size of electrically annealed samples was smaller than that of conventionally annealed samples. The hardness values and metallographic images obtained indicate that, unlike the conventional annealing process, which promotes restoration phenomena with increasing heating time, the electrical annealing process does not necessarily promote these phenomena. This difference is hypothesized to stem from conflicts between thermal and athermal effects during recrystallization.
The electrical signature of rock samples exposed to hydrostatic and triaxial pressures  [cached]
H. Heikamp,G. Nover
Annals of Geophysics , 2001, DOI: 10.4401/ag-3595
Abstract: The electrical signature of sedimentary (carbonate) and crystalline rock samples was studied in hydrostatic and triaxial pressure experiments up to 300 MPa. The aim was to establish a relation between an electrical signal stimulated by an external pressure acting on the sample and the mechanical stability of the rock. Natural open fractures tend to be closed under hydrostatic pressure conditions, whereas in triaxial pressure experiments new fractures are generated. These contrary processes of either decrease or increase in crack density and geometry, cause a decrease or increase in the inner surface of the sample. Such pressure induced variations in pore geometry were investigated by an interpretation and modelling of the frequency dependence of the complex electrical conductivity. In a series of hydrostatic pressure experiments crack-closure was found in the electrical signature by a decrease of the model capacitor C being related to crack geometry. This capacitor increases in the triaxial experiments where new fractures were formed.
Testing and Analysis of Induction Motor Electrical Faults Using Current Signature Analysis  [PDF]
K. Prakasam, S. Ramesh
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79229
Abstract: The proposed method deals with the emerging technique called as Motor Current Signature Analysis (MCSA) to diagnosis the stator faults of Induction Motors. The performance of the proposed method deals with the emerging technique called as Motor Current Signature Analysis (MCSA) and the Zero-Sequence Voltage Component (ZSVC) to diagnose the stator faults of Induction Motors. The unalleviated study of the robustness of the industrial appliances is obligatory to verdict the fault of the machines at precipitate stages and thwart the machine from brutal damage. For all kinds of industry, a machine failure escorts to a diminution in production and cost increases. The Motor Current Signature Analysis (MCSA) is referred as the most predominant way to diagnose the faults of electrical machines. Since the detailed analysis of the current spectrum, the method will portray the typical fault state. This paper aims to present dissimilar stator faults which are classified under electrical faults using MCSA and the comparison of simulation and hardware results. The magnitude of these fault harmonics analyzes in detail by means of Finite-Element Method (FEM). The anticipated method can effectively perceive the trivial changes too during the operation of the motor and it shows in the results.
Electrical Signature of Excitonic Electroluminescence and Mott Transition at Room Temperature  [PDF]
Kanika Bansal,Shouvik Datta
Physics , 2013,
Abstract: Mostly optical spectroscopies are used to investigate existence of excitons, Mott transitions and other exquisite excitonic condensed phases of matter. On the other hand, electrical signatures of excitons are hardly explored. Here we examine steady state, small signal, electrical response of AlGaInP based multi-quantum well laser diodes to identify and investigate the presence of excitons in electroluminescence. This frequency dependent response shows bias activated capacitance following a phenomenological rate equation. Dynamic dependence of this response on frequency reverses after light emission. This results in negative activation energy which we explain with the formation of a stable, intermediate transition state whose average energy matches well with excitonic binding energy of these III-V semiconductors. Hence we identify the presence of excitons which are also responsible for observed electroluminescence at low charge injections by electrical measurements alone. Further increase in charge injection suppresses the electrical signature of excitons representing their Mott transition into electron-hole plasma which is supported by standard optical measurements. This kind of correlation between electrical and optical properties of excitons was not systematically investigated in the past. Therefore, this study demonstrates a fresh experimental approach to electrically probe the rich and complex physics of excitons.
Signature inversion in axially deformed $^{160,162}$Tm  [PDF]
J. Kvasil,R. G. Nazmitdinov,A. Tsvetkov,P. Alexa
Physics , 2001, DOI: 10.1103/PhysRevC.63.061305
Abstract: The microscopic analysis of experimental data in $^{160,162}$Tm is presented within the two-quasiparticle-phonon model. The model includes the interaction between odd quasiparticles and their coupling with core vibrations. The coupling explains naturally the attenuation of the Coriolis interaction in rotating odd-odd nuclei. It is shown that the competition between the Coriolis and neutron-proton interactions is responsible for the signature inversion phenomenon.
Third type of domain wall in soft magnetic nanostrips  [PDF]
V. D. Nguyen,O. Fruchart,S. Pizzini,J. Vogel,J. -C. Toussaint,N. Rougemaille
Physics , 2015, DOI: 10.1038/srep12417
Abstract: Magnetic domain walls (DWs) in nanostructures are low-dimensional objects that separate regions with uniform magnetisation. Since they can have different shapes and widths, DWs are an exciting playground for fundamental research, and became in the past years the subject of intense works, mainly focused on controlling, manipulating, and moving their internal magnetic configuration. In nanostrips with in-plane magnetisation, two DWs have been identified: in thin and narrow strips, transverse walls are energetically favored, while in thicker and wider strips vortex walls have lower energy. The associated phase diagram is now well established and often used to predict the low-energy magnetic configuration in a given magnetic nanostructure. However, besides the transverse and vortex walls, we find numerically that another type of wall exists in permalloy nanostrips. This third type of DW is characterised by a three-dimensional, flux closure micromagnetic structure with an unusual length and three internal degrees of freedom. Magnetic imaging on lithographically-patterned permalloy nanostrips confirms these predictions and shows that these DWs can be moved with an external magnetic field of about 1mT. An extended phase diagram describing the regions of stability of all known types of DWs in permalloy nanostrips is provided.
Monte Carlo Investigation of Ising Nanotubes and Nanostrips  [PDF]
Carlos Garcia,M. Felisa Martinez,Julio A. Gonzalo
Physics , 2003,
Abstract: Monte Carlo simulations of the magnetization temperature dependence in $D\times L$ nanotubes (periodic lateral boundary conditions) and nanostrips (free lateral boundary conditions) with $D$=8, 16, 32, 64$\ll L\longrightarrow 5000$ have been performed. The apparent critical temperature was determinated using the Binder Cumulant method (crossing of data for $D\times L$ with data for $D\times 2L)$ and it was found to be $ T_{C}=0 $ for small $D$ values $(D
Reversible, electrical and optical switching on silver 3-phenyl-1-ureidonitrile complex thin films
Reversible,electical and optical switching on silver 3—phenyl—1—ureidonitrile complex thin films

Zhang Hao-Xu,Shi Dong-Xi,Song Yan-Lin,Liu Hong-Wen,Hou Shi-Min,Xue Zeng-Quan,Gao Hong-Jun,

中国物理 B , 2002,
Abstract: We report on the reversible, electrical and optical switching on silver 3-phenyl-1-ureidonitrile complex thin films. The films can switch from a high impedance state to a low impedance state with an applied electric field at the threshold of 3.5×107V/m. Furthermore, the films can be switched back to the original state by treating the samples at about 80℃. The optical recording is fulfilled using a semiconductor laser with a wavelength of 780 nm. Erasure can be accomplished by bulk heating or by the laser working with the power beneath the threshold. No loss of the organic was found in the experiments. This material may have a potential application in ultrahigh data density storage.
Manipulating domain wall chirality by current pulses in Permalloy/Ir nanostrips  [PDF]
Zahid Ishaque,Van Dai Nguyen,Olivier Fruchart,Stefania Pizzini,Nicolas Rougemaille,Svenja Perl,Jean-Christophe Toussaint,Jan Vogel
Physics , 2013,
Abstract: Using magnetic force microscopy and micromagnetic simulations, we studied the effect of Oersted magnetic fields on the chirality of transverse magnetic domain walls in Fe$_{20}$Ni$_{80}$/Ir bilayer nanostrips. Applying nanosecond current pulses with a current density of around $2\times10^{12}$ A/m$^2$, the chirality of a transverse domain wall could be switched reversibly and reproducibly. These current densities are similar to the ones used for current-induced domain wall motion, indicating that the Oersted field may stabilize the transverse wall chirality during current pulses and prevent domain wall transformations.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.