A New Technique for Contact Mechanics and Friction in Microstructures: Controllable Electrostatic Repulsive Forces From Capacitive Coupling to Electret

2005 ◽  
Author(s):  
Myongseob Kim ◽  
Chungho Lee ◽  
Edwin C. Kan
Keyword(s):  
Charge Density ◽  
Polymer Film ◽  
Contact Mechanics ◽  
Repulsive Force ◽  
Capacitive Coupling ◽  
Cantilever Beams ◽  
Static Charge ◽  
Actuation Mechanism ◽  
A New Technique ◽  
Repulsive Forces

The use of the electrostatically repulsive force from the capacitive coupling with electret polymer film is demonstrated experimentally. The repulsive forces can be utilized in controlling contact mechanics and friction in microstructures, and serve as an alternative MEMS actuation mechanism to overcome the limitations by the attractive forces. Simple parallel cantilever beams patterns are used to illustrate the magnitude of the repulsive forces and the associated static charge density from the electret polymer films coupling.

DETERMINATION OF THE REPULSIVE FORCE OF A THICK HIGH-COERCIVE PERMANENT MAGNETS IN THE AXIAL BEARING OF A VERTICAL PUMP

2021 ◽  
pp. 23-27
Author(s):  
A. Ya. Krasil’nikov ◽  
A. A. Krasil’nikov
Keyword(s):  
Standard Method ◽  
Permanent Magnets ◽  
Magnetic System ◽  
Repulsive Force ◽  
Cobalt Alloy ◽  
Average Value ◽  
The North ◽  
Repulsive Forces ◽  
North And South

The article considers the possibility of applying a standard method for calculating the repulsive force for a thick high-coercive permanent magnets from samarium-cobalt alloy in a magnetic system. The results of the research allowed us to introduce correction coefficients in the method of calculating the repulsive force in a magnetic system with such magnets, depending on the air gap between of them. It is shown that the repulsive forces of the North poles of permanent magnets differ from the repulsive forces of the South poles. The research was carried out with magnets manufactured by different enterprises. When calculating the repulsive force, the average value of the repulsive force between the North and South poles of magnets is found.

A new technique for determining the capacitive coupling coefficients in flash EPROMs

1992 ◽  
Vol 13 (6) ◽  
pp. 328-331 ◽  
Author(s):  
K.T. San ◽  
C. Kaya ◽  
D.K.Y. Liu ◽  
T.-P. Ma ◽  
P. Shah
Keyword(s):  
Capacitive Coupling ◽  
New Technique ◽  
Coupling Coefficients ◽  
A New Technique

scholarly journals Interpretations of ground-state symmetry breaking and strong correlation in wavefunction and density functional theories

2021 ◽  
Vol 118 (4) ◽  
pp. e2017850118 ◽  
Author(s):  
John P. Perdew ◽  
Adrienn Ruzsinszky ◽  
Jianwei Sun ◽  
Niraj K. Nepal ◽  
Aaron D. Kaplan
Keyword(s):  
Density Functional Theory ◽  
Charge Density ◽  
Ground State ◽  
Charge Density Wave ◽  
Density Functional ◽  
Density Wave ◽  
Static Charge ◽  
Functional Theory ◽  
Correlation Kernel ◽  
Frequency Moments

Strong correlations within a symmetry-unbroken ground-state wavefunction can show up in approximate density functional theory as symmetry-broken spin densities or total densities, which are sometimes observable. They can arise from soft modes of fluctuations (sometimes collective excitations) such as spin-density or charge-density waves at nonzero wavevector. In this sense, an approximate density functional for exchange and correlation that breaks symmetry can be more revealing (albeit less accurate) than an exact functional that does not. The examples discussed here include the stretched H2 molecule, antiferromagnetic solids, and the static charge-density wave/Wigner crystal phase of a low-density jellium. Time-dependent density functional theory is used to show quantitatively that the static charge-density wave is a soft plasmon. More precisely, the frequency of a related density fluctuation drops to zero, as found from the frequency moments of the spectral function, calculated from a recent constraint-based wavevector- and frequency-dependent jellium exchange-correlation kernel.

scholarly journals A Low Voltage Electrostatic Micro Actuator for Large Out-of-Plane Displacement

2014 ◽  
Author(s):  
Shahrzad Towfighian ◽  
Siyuan He ◽  
Ridha Ben Mrad
Keyword(s):  
Low Voltage ◽  
Element Model ◽  
Repulsive Force ◽  
Low Voltage Operation ◽  
Out Of Plane ◽  
Static Modeling ◽  
Previous Design ◽  
Repulsive Forces ◽  
Plane Displacement ◽  
Auto Focusing

An electrostatic actuator is designed to move a 1 mm mirror, 58 μm out of plane at 25 volts. Large out-of-plane displacement is obtained from repulsive forces generated on four sets of comb drive fingers attached to the mirror plate in the middle. The proposed actuator is a customized design of a previous study for low voltage applications. The static modeling of the actuator was performed using a coupled-field finite element model of the actuator, including mechanical and electrical domains. Low voltage operation is achieved by decreasing the finger width and the lateral spacing, which increased the generated repulsive force at a specified voltage in a unit cell of the actuator. Decreasing the lateral spacing also enabled increasing the number of fingers, which could increase the repulsive-force, and consequently the torque and the rotation angles when the vertical gap between moving and fixed fingers is small. However, the redesigned actuator has a lower stiffness compared to the previous design. The actuator is optimized for auto-focusing applications in cell phone cameras that require voltages below 30 Volts for user safety. In the intended auto-focusing module, the actuators do not carry the lens and auto-focusing is obtained by moving the mirror attached to the actuators.

scholarly journals The similarity of attractive and repulsive forces on a lattice

2015 ◽  
Vol 30 (23) ◽  
pp. 1550112
Author(s):  
Marjan-S. Mirahmadi ◽  
Amir H. Fatollahi ◽  
Mohammad Khorrami
Keyword(s):  
Kinetic Energy ◽  
Energy Band ◽  
Bound States ◽  
Repulsive Force ◽  
Attractive Force ◽  
Similar System ◽  
Piecewise Constant ◽  
One Dimensional ◽  
Constant Potential ◽  
Repulsive Forces

On a lattice, as the momentum space is compact, the kinetic energy is bounded not only from below but also from above. It is shown that this somehow removes the distinction between repulsive and attractive forces. In particular, it is seen that a region with attractive force would appear forbidden for states with energies higher than a certain value, while repulsive forces could develop bound-states. An explicit transformation is introduced which transforms the spectrum of a system corresponding to a repulsive force, to that of a similar system corresponding to an attractive force. Explicit numerical examples are presented for discrete energies of bound-states of a particle experiencing repulsive force by a piecewise constant potential. Finally, the parameters of a specific one-dimensional (1D) translationally invariant system on continuum are tuned so that the energy of the system resembles the kinetic energy of a system on a 1D lattice. In particular, the parameters are tuned so that while the width of the first energy band and its position are kept finite, the gap between the first energy band and the next energy band goes to infinity, so that effectively only the first energy band is relevant.

Charge Density Limits in Polymer Film Electrets

2006 ◽  
Author(s):  
M.A. Parada ◽  
H. Zaias ◽  
A. de Almeida ◽  
D. Ila
Keyword(s):  
Charge Density ◽  
Polymer Film

d-wave pairing in the doped static charge-density-wave state on a two-dimensional square lattice

2000 ◽  
Vol 62 (14) ◽  
pp. 9648-9653 ◽  
Author(s):  
Mikio Onozawa ◽  
Yoshiyuki Fukumoto ◽  
Akihide Oguchi ◽  
Yukio Mizuno
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Square Lattice ◽  
Two Dimensional ◽  
Static Charge ◽  
Wave State ◽  
Wave Pairing ◽  
D Wave

Design and Experimental Test of ER Fluid Based 3-DOF Haptic Master System for MIS

2011 ◽  
Vol 317-319 ◽  
pp. 600-603
Author(s):  
Seung Gu Lim ◽  
Phuong Bac Nguyen ◽  
Seung Bok Choi
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Experimental Test ◽  
Repulsive Force ◽  
Complex Rotation ◽  
Master System ◽  
Repulsive Forces ◽  
Er Fluid ◽  
Master Device

This paper presents a new design of an electro-rheological (ER) fluid-based haptic master device that is used for a minimally invasive surgery (MIS). This device consists of a bi-directional ER clutch/brake and an ER brake from which a repulsive force is realized. First, the modeling of these clutches/brakes is conducted. In addition, to transmit a complex rotation from the handle of the device to three independently rotary movements, a gimbal mechanism is adopted. At last, in order to evaluate the repulsive forces generated from the device, an experimental test is undertaken.

Sign in / Sign up

Export Citation Format

Share Document