scholarly journals Nonlinear friction dynamics on polymer surface under accelerated movement

AIP Advances ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 045005 ◽  
Author(s):  
Yuuki Aita ◽  
Natsumi Asanuma ◽  
Akira Takahashi ◽  
Hiroyuki Mayama ◽  
Yoshimune Nonomura
2009 ◽  
Vol 16-19 ◽  
pp. 826-830
Author(s):  
Yong Fu Wang ◽  
Hua Long Cao ◽  
Yi Min Zhang ◽  
Bang Chun Wen

Modeling of friction force has been a challenging task in mechanical engineering. Traditional way, such as mathematical modeling approaches, was found quite difficult to achieve satisfactory performances due to some immanent nonlinearity and uncertainties in systems. This paper aims to develop fuzzy modeling techniques to characterize the friction dynamics. The proposed fuzzy modeling approach has two folds, that is, extraction of fuzzy rules using data mining techniques; setup of static model based on the fuzzy rules. The results obtained demonstrate that our proposed method in this paper has good potential in many mechanical systems with unknown nonlinear friction.


2020 ◽  
Vol 51 (5) ◽  
pp. 779-788
Author(s):  
Hina Okawara ◽  
Koki Shinomiya ◽  
Minoru Fujita ◽  
Tomonori Koda ◽  
Akihiro Nishioka ◽  
...  

Author(s):  
I. H. Musselman ◽  
R.-T. Chen ◽  
P. E. Russell

Scanning tunneling microscopy (STM) has been used to characterize the surface roughness of nonlinear optical (NLO) polymers. A review of STM of polymer surfaces is included in this volume. The NLO polymers are instrumental in the development of electrooptical waveguide devices, the most fundamental of which is the modulator. The most common modulator design is the Mach Zehnder interferometer, in which the input light is split into two legs and then recombined into a common output within the two dimensional waveguide. A π phase retardation, resulting in total light extinction at the output of the interferometer, can be achieved by changing the refractive index of one leg with respect to the other using the electrooptic effect. For best device performance, it is essential that the NLO polymer exhibit minimal surface roughness in order to reduce light scattering. Scanning tunneling microscopy, with its high lateral and vertical resolution, is capable of quantifying the NLO polymer surface roughness induced by processing. Results are presented below in which STM was used to measure the surface roughness of films produced by spin-coating NLO-active polymers onto silicon substrates.


Author(s):  
Daniel L. Callahan ◽  
H. M. Phillips ◽  
R. Sauerbrey

Excimer laser irradiation has been used to interferometrically ablate submicron line patterns on to Kapton polyimide. Such patterned material may exhibit highly anisotropic conduction as was predicted from previous studies showing enhanced conductivity from uniformly ablated material. We are currently exploiting this phenomenon to create integrated devices using conventional polymers as both dielectrics and conductors. Extensive scanning electron microscopy (SEM) and limited transmission electron microscopy (TEM) have been conducted in order to characterize the morphology of such patterned nanostructures as a function of processing conditions.The ablation technique employed produces an interference pattern on the polymer surface of period equal to half that of a diffraction grating period, independent of the laser wavelength. In these experiments, a 328 nm grating has been used to produce line patterns of 164 nm line-spacings as shown in Figures 1 and 2. A 200 Å Au coating has been used to both prevent charging and, perhaps more importantly, enhance contrast.


Author(s):  
W.W. Adams ◽  
G. Price ◽  
A. Krause

It has been shown that there are numerous advantages in imaging both coated and uncoated polymers in scanning electron microscopy (SEM) at low voltages (LV) from 0.5 to 2.0 keV compared to imaging at conventional voltages of 10 to 20 keV. The disadvantages of LVSEM of degraded resolution and decreased beam current have been overcome with the new generation of field emission gun SEMs. In imaging metal coated polymers in LVSEM beam damage is reduced, contrast is improved, and charging from irregularly shaped features (which may be unevenly coated) is reduced or eliminated. Imaging uncoated polymers in LVSEM allows direct observation of the surface with little or no charging and with no alterations of surface features from the metal coating process required for higher voltage imaging. This is particularly important for high resolution (HR) studies of polymers where it is desired to image features 1 to 10 nm in size. Metal sputter coating techniques produce a 10 - 20 nm film that has its own texture which can obscure topographical features of the original polymer surface. In examining thin, uncoated insulating samples on a conducting substrate at low voltages the effect of sample-beam interactions on image formation and resolution will differ significantly from the effect at higher accelerating voltages. We discuss here sample-beam interactions in single crystals on conducting substrates at low voltages and also present the first results on HRSEM of single crystal morphologies which show some of these effects.


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