1,721,062 research outputs found
performance enhancement for pneumatic vibration isolation tables in low frequency by active control
No full textConsideration of static-strain-dependent complex modulus in dynamic stiffness calculation of mount/bushing by commercial finite element codes
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FORMATION OF SELF-ASSEMBLED POLYELECTROLYTE MULTILAYER NANODOTS BY SCANNING PROBE MICROSCOPY
No full textWe demonstrate that patterned nanodots can be obtained from alternatively Self-assembled polyelectrolytes which consist of poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) by using atomic force microscopy. The surface potentials are easily reversible as positive or negative depending on the kind of the top polyelectrolyte layer. With the layer by layer growth, the nanodots are formed exactly on the charged area and their thicknesses proportionally increase to the total number of monolayers with a uniform thickness of about 0.5 nm.X115sciescopu
Surface charge dynamics on ferroelectric PbZr0.48Ti0.52O3 films responding to the switching bias of electric force microscope
Full text linkWe investigated the role of surface charges in writing and reading ferroelectric bits on an epitaxial PbZr0.48Ti0.52O3 thin film by electric force microscopy (EFM). The sign of EFM surface potential was reversed within several hundred microseconds for 10 V. For a negative bias voltage of -10 V, EFM surface potential was reversed in several milliseconds. The different time scales of the EFM surface potential reversals originate from the screening of the ferroelectric polarization charges by the surface charges which pass over two different Schottky barriers depending on the applied bias polarity.X118sciescopu
Nucleation and growth mechanism of ferroelectric domain-wall motion
No full textThe motion of domain walls is critical to many applications involving ferroelectric materials, such as fast high-density non-volatile random access memory(1). In memories of this sort, storing a data bit means increasing the size of one polar region at the expense of another, and hence the movement of a domain wall separating these regions. Experimental measurements of domain growth rates in the well-established ferroelectrics PbTiO(3) and BaTiO(3) have been performed, but the development of new materials has been hampered by a lack of microscopic understanding of how domain walls move(2-11). Despite some success in interpreting domain-wall motion in terms of classical nucleation and growth models(12-16), these models were formulated without insight from first-principles-based calculations, and they portray a picture of a large, triangular nucleus that leads to unrealistically large depolarization and nucleation energies(5). Here we use atomistic molecular dynamics and coarse-grained Monte Carlo simulations to analyse these processes, and demonstrate that the prevailing models are incorrect. Our multi-scale simulations reproduce experimental domain growth rates in PbTiO(3) and reveal small, square critical nuclei with a diffuse interface. A simple analytic model is also proposed, relating bulk polarization and gradient energies to wall nucleation and growth, and thus rationalizing all experimental rate measurements in PbTiO(3) and BaTiO(3).X11202sciescopu
Lyapunov instability of rigid diatomic molecules via diatomic potential molecular dynamics
No full textWe develop a molecular dynamic method to evaluate the full Lyapunov spectrum for two-dimensonal fluids composed of rigid diatomic molecules. The Lyapunov spectra are obtained for 18 rigid diatomic molecules for various bond lengths d(10(-3)less than or equal to d less than or equal to 1.0) in two dimensions with periodic boundary conditions, and interacting with Hoover and Weeks-Chandler-Anderson short-range repulsive forces. The general trends and characteristic features of the Lyapunov spectra are examined for both potentials. Our results are compared with those obtained from I. Borzsak et al. [Phys. Rev. E 53, 3694 (1996)], whose model uses the Lagrange multiplier method. [S1063-651X(98)06612-4]
A study on response analysis of pneumatic vibration isolation table loaded by transient movements of carriage on it
No full textConsideration of static-strain-dependent dynamic complex modulus in dynamic stiffness calculation of mount/bushing by commercial finite element codes
Full text linkA study on response analysis of 6-DOF pneumatic vibration isolation table loaded by transient movements of carriage on it
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