scholarly journals Highly Sensitive Tactile Shear Sensor Using Spatially Digitized Contact Electrodes

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1300 ◽  
Author(s):  
Eunsuk Choi ◽  
Soonhyung Hwang ◽  
Yousang Yoon ◽  
Hojun Seo ◽  
Jusin Lee ◽  
...  
Keyword(s):  
Graphene Layer ◽  
Surface Friction ◽  
Shear Direction ◽  
Shear Forces ◽  
Ridge Structure ◽  
Surgical Tools ◽  
Bottom Substrate ◽  
Highly Sensitive ◽  
Shear Sensor ◽  
Contact Electrodes

In this article, we report on a highly sensitive tactile shear sensor that was able to detect minute levels of shear and surface slip. The sensor consists of a suspended elastomer diaphragm with a top ridge structure, a graphene layer underneath, and a bottom substrate with multiple spatially digitized contact electrodes. When shear is applied to the top ridge structure, it creates torque and deflects the elastomer downwards. Then, the graphene electrode makes contact with the bottom spatially digitized electrodes completing a circuit producing output currents depending on the number of electrodes making contact. The tactile shear sensor was able to detect shear forces as small as 6 μN, detect shear direction, and also distinguish surface friction and roughness differences of shearing objects. We also succeeded in detecting the contact slip motion of a single thread demonstrating possible applications in future robotic fingers and remote surgical tools.

3D SOI Elements for System-on-Chip Applications

2011 ◽  
Vol 276 ◽  
pp. 137-144 ◽  
Author(s):  
I.T. Kogut ◽  
A.A. Druzhinin ◽  
V.I. Holota
Keyword(s):  
Field Emission ◽  
Schottky Diodes ◽  
System On Chip ◽  
Emission Current ◽  
Electrical Characteristics ◽  
Field Emission Current ◽  
Highly Sensitive ◽  
On Chip ◽  
Contact Electrodes ◽  
Original Device

Base technology of local 3D SOI-structures formation has been proposed. Using this technology the electrical characteristics were developed and simulated of following original device elements for the microsystem applications: standard and matrix SOI CMOS-transistors with 3D gates, switching elements on Schottky diodes, contact electrodes with 3D surface, elements for highly sensitive integral accelerometers with registration of a field emission current, hermetical microcavities and microchannels under the surface of a SOI-substrate, field emission silicon microcathodes.

Simultaneous Measurements of Friction Forces and Contact Areas During Shearing of Nanometer-Thick Liquid Lubricant Films

2012 ◽  
Author(s):  
Shintaro Itoh ◽  
Takumi Mizuno ◽  
Yusuke Norizuki ◽  
Kenji Fukuzawa ◽  
Hedong Zhang
Keyword(s):  
Mechanical Properties ◽  
Contact Area ◽  
Microelectromechanical Systems ◽  
Hard Disk Drives ◽  
Disk Drives ◽  
Shear Forces ◽  
Friction Forces ◽  
Liquid Lubricant ◽  
Highly Sensitive ◽  
Lubricant Films

Nanometer-thick liquid lubricant films are useful for the lubrication of miniaturized mechanical systems, such as hard disk drives or microelectromechanical systems. However, there are no established methods for measuring the mechanical properties of such thin films, which can be an obstacle to the optimal design of lubrication systems. We previously developed a highly sensitive method for measuring shear forces, which we called the fiber-wobbling method (FWM). In the FWM, we used a ball-ended optical fiber to probe shear and we measured the friction force acting on the probe tip by detecting the deflection of the fiber. By this means we succeeded in measuring friction forces in nanometer-thick liquid lubricant films. However, we could not evaluate the mechanical properties of the films quantitatively because the contact area between the probe tip and lubricant film was unknown. Here, we developed a method for measuring the contact area during shearing of nanometer-thick liquid lubricant films in the FWM.

scholarly journals Correlation of fingertip shear force direction with somatosensory cortical activity in monkey

2016 ◽  
Vol 115 (1) ◽  
pp. 100-111 ◽  
Author(s):  
Pascal Fortier-Poisson ◽  
Jean-Sébastien Langlais ◽  
Allan M. Smith
Keyword(s):  
Cortical Neurons ◽  
Shear Force ◽  
Directional Sensitivity ◽  
Shear Direction ◽  
Dynamic Shear ◽  
Shear Forces ◽  
Force Direction ◽  
Powerful Stimulus ◽  
Area 3B ◽  
Static Shear

To examine the activity of somatosensory cortex (S1) neurons to self-generated shear forces on the index and thumb, two monkeys were trained to grasp a stationary metal tab with a key grip and exert forces without the fingers slipping in one of four orthogonal directions for 1 s. A majority (∼85%) of slowly adapting and rapidly adapting (RA) S1 neurons had activity modulated with shear force direction. The cells were recorded mainly in areas 1 and 2 of the S1, although some area 3b neurons also responded to shear direction or magnitude. The preferred shear vectors were distributed in every direction, with tuning arcs varying from 50° to 170°. Some RA neurons sensitive to dynamic shear force direction also responded to static shear force but within a narrower range, suggesting that the direction of the shear force may influence the adaptation rate. Other neurons were modulated with shear forces in diametrically opposite directions. The directional sensitivity of S1 cortical neurons is consistent with recordings from cutaneous afferents showing that shear direction, even without slip, is a powerful stimulus to S1 neurons.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Various technic for the measurement of step thickness on crystal surfaces

1978 ◽  
Vol 36 (1) ◽  
pp. 438-439
Author(s):  
C. Boulesteix ◽  
C. Colliex ◽  
C. Mory ◽  
B. Pardo ◽  
D. Renard
Keyword(s):  
Critical Thickness ◽  
Symmetric Case ◽  
Transmitted Intensity ◽  
Crystal Surfaces ◽  
Bright Field ◽  
Excited Wave ◽  
Highly Sensitive ◽  
Contrast Mechanisms ◽  
Step Thickness ◽  
Thickness Variations

Contrast mechanisms, which are responsible of the various types of image formation, are generally thickness dependant. In the following, two imaging modes in the 100 kV CTEM are described : they are highly sensitive to thickness variations and can be used for quantitative estimations of step heights.Detailed calculations (1) of the bright-field intensity have been carried out in the 3 (or 2N+l)-beam symmetric case. They show that in given conditions, the two important symmetric Bloch waves interfere most strongly at a critical thickness for which they have equal emergent amplitudes (the more excited wave at the entrance surface is also the more absorbed). The transmitted intensity I for a Nd2O3 specimen has been calculated as a function of thickness t. The capacity of the method to detect a step and measure its height can be more clearly deduced from a plot of dl/Idt as shown in fig. 1.

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