Current Issue : April - June Volume : 2017 Issue Number : 2 Articles : 5 Articles
Cave animals are often adapted to digging and life underground, with claw toes similar in structure and function to a sampling\nscoop. In this paper, the clawed toes of the Himalayan marmot were selected as a biological prototype for bionic research. Based\non geometric parameter optimization of the clawed toes, a bionic sampling scoop for use on Mars was designed. Using a 3D laser\nscanner, the point cloud data of the second front claw toe was acquired. Parametric equations and contour curves for the claw were\nthen built with cubic polynomial fitting.We obtained 18 characteristic curve equations for the internal and external contours of the\nclaw. A bionic sampling scoop was designed according to the structural parameters of Curiosityââ?¬â?¢s sampling shovel and the contours\nof the Himalayan marmotââ?¬â?¢s claw. Verifying test results showed that when the penetration angle was 45âË?Ë? and the sampling speed\nwas 0.33 r/min, the bionic sampling scoopsââ?¬â?¢ resistance torque was 49.6% less than that of the prototype sampling scoop.When the\npenetration angle was 60âË?Ë? and the sampling speed was 0.22 r/min, the resistance torque of the bionic sampling scoop was 28.8%\nlower than that of the prototype sampling scoop....
Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template\nmodels to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg\nspring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity\nof spring-legged robots. In this paper, we investigate the effects of ââ?¬Å?Jââ?¬Â-curve spring stiffness inspired by biological materials on running\nspeeds of segmented legs during high-speed locomotion.Mathematical formulation of the relationship between the virtual leg\nforce and the virtual leg compression is established.When the SLIP model and the two-segment leg model with constant spring stiffness\nand with ââ?¬Å?Jââ?¬Â-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with ââ?¬Å?Jââ?¬Â-curve\nspring stiffness reveals that (1) both the largest tolerated range of running speeds and the tolerated maximum running speed are\nfound and (2) at fast running speed from25 to 40/92msâË?â??1 both the tolerated range of landing angle and the stability region are the\nlargest. It is suggested that the two-segment leg model with ââ?¬Å?Jââ?¬Â-curve spring stiffness is more advantageous for high-speed running\ncompared with the SLIP model and with constant spring stiffness....
This paper proposes a neural stimulation device integrated with a silicon nanowire\n(SiNW)-based photodetection circuit for the activation of neurons with light. The proposed device\nis comprised of a voltage divider and a current driver in which SiNWs are used as photodetector\nand field-effect transistors; it has the functions of detecting light, generating a stimulation signal\nin proportion to the light intensity, and transmitting the signal to a micro electrode. To show the\napplicability of the proposed neural stimulation device as a high-resolution retinal prosthesis system,\na high-density neural stimulation device with a unit cell size of 110 Ã?â?? 110 Ã?¼m and a resolution of\n32 Ã?â?? 32 was fabricated on a flexible film with a thickness of approximately 50 Ã?¼m. Its effectiveness\nas a retinal stimulation device was then evaluated using a unit cell in an in vitro animal experiment\ninvolving the retinal tissue of retinal Degeneration 1 (rd1) mice. Experiments wherein stimulation\npulses were applied to the retinal tissues successfully demonstrate that the number of spikes in neural\nresponse signals increases in proportion to light intensity....
In this research, we investigated the influence of the surface coatings of silver nanowires\non the sensitivity of surface acoustic wave (SAW) humidity sensors. Silver nanowires, with\npoly(vinylpyrrolidone) (PVP), which is a hydrophilic capping agent, were chemically synthesized,\nwith an average length of 15 �¼m and an average diameter of 60 nm. Humidity sensors, with 433 MHz\nfrequency dual-port resonator Rayleigh-SAW devices, were coated by silver nanowires (AgNWs)\nusing the electrospray coating method. It was demonstrated that increasing thickness of coated\nAgNW on the surfaces of SAW devices results in increased sensitivity. The highest frequency shift\n(262 kHz) in these SAW devices was obtained with an injection of 0.5 mL of the AgNW solution with\na concentration of 0.5 mg/mL at an injection rate of 1 mL/h. It also showed the highest humidity\nsensitivity among the other prepared SAW devices....
Monodispersed Bi-Tenano arrays are achieved via template-free bipotentiostatic\ndeposition. The diameter and length of individual nanorod is ~80 nm\nand ~250 nm respectively. The electrodeposition process is demonstrated to\nfollow a two-step mechanism: an instantaneous reductive potential is applied\nto form dispersive nuclei, then a reversal oxidative potential strips partial Bi\natoms to prevent further cross-growth. Repeatedly, the nano arrays film is\nobtained eventually. The thermoelectric properties of the obtained Bi-Tenano\narrays such as electrical resistance, carrier density, Seebeck coefficient and\npower factor are measured to be 2.438 Ã?â?? 10âË?â??4 Ã?©Ã?·m, 4.251 Ã?â?? 1020 cmâË?â??3, âË?â??25.892\nÃ?¼VÃ?·KâË?â??1, 2.750 Ã?â?? 10âË?â??6 WÃ?·mâË?â??1Ã?·K2, respectively....
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