نتایج جستجو برای: piezoelectric

تعداد نتایج: 13993  

2006
Gwo-Ruey Yu

This paper presents the nano-positioning control of a piezoelectric platform. A Bouc-Wen model is established to describe the nonlinear hysteretic effect of piezoelectric systems. Three kinds of compensators, traditional PI controller, PI-like fuzzy logic controller (FLC) and adaptive PI-FLC controller, are designed for the piezoelectric systems. The adaptive PI controller is tuned on-line by m...

2014
Zhigang Sun Xianqiao Wang

Piezoelectric material has been emerging as a popular building block in MEMS devices owing to its unique mechanical and electrical material properties. However, the reliability of MEMS devices under buckling deformation environments remains elusive and needs to be further explored. Based on the Talreja's tensor valued internal state damage variables as well as the Helmhotlz free energy of piezo...

2017
Noëlle Gogneau Nicolas Jamond Pascal Chrétien Frédéric Houzé Elie Lefeuvre M Tchernycheva N. Gogneau N. Jamond P. Chrétien F. Houzé E. Lefeuvre M. Tchernycheva

Ambient energy harvesting using piezoelectric nanomaterials is today considered as a promising way to supply microelectronic devices. Since the first demonstration of electrical energy generation from piezoelectric semiconductor nanowires in 2006, the piezoelectric response of 1D-nanostructures and the development of nanowirebased piezogenerators have become a hot topic in nanoscience. After se...

2003
Shining Zhu Bei Jiang Wenwu Cao

Resonance technique for determining the physical properties of piezoelectric material can be difficult to implement for some low symmetry systems. Inconstancy may be introduced because several samples are needed and the degree of poling depends on sample geometry. The ultrasonic method on the other hand, allows the determination of a complete set of elastic, piezoelectric, dielectric constants ...

Journal: :Nano letters 2011
Ravi Agrawal Horacio D Espinosa

Nanowires made of materials with noncentrosymmetric crystal structure are under investigation for their piezoelectric properties and suitability as building blocks for next-generation self-powered nanodevices. In this work, we investigate the size dependence of piezoelectric coefficients in nanowires of two such materials - zinc oxide and gallium nitride. Nanowires, oriented along their polar a...

Journal: :Nano letters 2010
Xi Chen Shiyou Xu Nan Yao Yong Shi

Energy harvesting technologies that are engineered to miniature sizes, while still increasing the power delivered to wireless electronics, (1, 2) portable devices, stretchable electronics, (3) and implantable biosensors, (4, 5) are strongly desired. Piezoelectric nanowire- and nanofiber-based generators have potential uses for powering such devices through a conversion of mechanical energy into...

2017
Lev Eppelbaum

The piezoelectric and seismo-electrokinetic phenomena are manifested by electrical and electromagnetic processes that occur in rocks under the influence of elastic oscillations triggered by shots or mechanical impacts. Differences in piezoelectric properties between the studied targets and host media determine the possibilities of the piezoelectric/seismoelectric method application. Over a long...

2014
Arian Bahrami

This paper demonstrates the potential of applying PDlike fuzzy logic controller for active vibration control of piezoelectric Stewart platforms. Through simulation, the control authority of the piezo stack actuators for effectively damping the Stewart platform vibration can be evaluated for further implementation of the system. Each leg of the piezoelectric Stewart platform consists of a linear...

Journal: :Physical review letters 2006
Gabriel Bester Xifan Wu David Vanderbilt Alex Zunger

We show that the piezoelectric effect that describes the emergence of an electric field in response to a crystal deformation in III-V semiconductors such as GaAs and InAs has strong contributions from second-order effects that have been neglected so far. We calculate the second-order piezoelectric tensors using density-functional theory and obtain the piezoelectric field for [111]-oriented In(x...

2004
K. Mossi R. Bryant

During the past decade, piezoelectric actuators as the active element in synthetic jets demonstrated that they could significantly enhance the overall lift on an airfoil. However, durability, system weight, size, and power have limited their use outside a laboratory. These problems are not trivial, since piezoelectric actuators are physically brittle and display limited displacement. The object...

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