Search

Traditional gait analysis systems based on 3D motion capture system require large, expensive equipment and specialists to operate the system, presenting time and space constraints. Although various studies have been conducted on developing wearable gait analysis devices, the results were discontinuous, there were limitations in dividing the gait phases, and appropriate responses to changes in physical conditions and walking speed were not demonstrated. To overcome these problems, the present study developed an insole device fitted with force sensing resistors for the measurement of the ground reaction force, and designed a gait analysis technique based on results from a gait experiment conducted on eight healthy male adults. This novel gait analysis algorithm examined the forward and lateral centers of the pressure values generated during gait, ratio of these two values for the division of the gait cycle into eight phases, and identification of the point when the weight support transition between the two feet occurred. The data acquisition system (DAS), comprising the developed insole device and wireless data transceiver, is expected to be applicable for activities of daily living because it can be manufactured as a small, lightweight wearable device, and the proposed gait analysis technique is unaffected by the walking speed and physical conditions of the wearer. [ABSTRACT FROM AUTHOR]

A novel 3D vertical structure that can store both information and energy is proposed in this letter. For the fabrication of 3D structural devices, an isolation layer (IL) is essential because it prevents interference between each cell of the device. Given that it occupies a large volume in the 3D structure, the IL can be more effectively utilized. In particular, for energy efficiency, an energy-storage device can be adopted into the IL; thus, both energy and information can be stored in the same volume using the proposed hybrid 3D vertical structure. The demonstration of the proposed structure showed a strong potential for various fields of 3D stackable devices that require high-density integration and energy efficiency. [ABSTRACT FROM AUTHOR]

An ionic electrochemical-reaction-based two-terminal synaptic device (Ionic Synapse) is developed for improved weight updating in hardware-based neuromorphic systems. The developed ionic synapse consists of an anode and a cathode that have the typical structure of a rechargeable battery. It can migrate metal ions from the anode (cathode) to the cathode (anode) under electrical bias, yielding total conductance changes. Analysis of the fabricated device reveals that the conductance changes are strongly dependent on the amounts of migrated ions, which can be sensitively controlled using applied identical pulses. Consequently, improved linearity for weight-updating is successfully achieved. These findings indicate the potential of the ionic electrochemical reaction mechanism for the realization of a desirable two-terminal synaptic device. [ABSTRACT FROM AUTHOR]

We propose a titanium oxide (TiOx)-based temperature sensor that can be operated in two ways, namely, by showing either abrupt or gradual metal–insulator transition (MIT) characteristics. For an as-prepared reliable TiOx-based MIT device, both abrupt and gradual MIT characteristics were observed under varying bias and temperature conditions. These results strongly demonstrate that two different types of temperature sensor (critical temperature sensor and differential temperature sensor) can be selectively operated by varying the applied bias in a single MIT device. [ABSTRACT FROM AUTHOR]

The flexible logic circuit configured using Si-based memristive switches is demonstrated. The memristive switches consisting of Ag/a-Si/heavily doped p-type Si are constructed on plastic using top-down-fabricated Si nanowires. The logic gate analyses provide insight toward logic circuits having multifunctionality and high connectivity through a crossbar-array architecture. With the strong stability of the logic performances against external strain, the memristive switch looks promising as a building block for flexible electronics. [ABSTRACT FROM AUTHOR]

A sharp contrast on the density and size of Ga metal droplets is observed on various photolithographically patterned GaAs (100). As clearly evidenced by high-resolution scanning electron microscope, Ga metal droplet density and size surprisingly differ on etched and unetched surfaces under an identical growth condition. The apparent contrast on the density and size of droplets is clearly observed at the interface between etched and unetched areas. Ga droplets exhibit much higher density and the size is much smaller on etched surface; meanwhile, the density is an order of magnitude lower and the size is much larger on unetched surface. Along different directions, [011] and [01-1], due to anisotropic surface diffusion, the density is about twice higher along [011] for the same strip pattern. [ABSTRACT FROM PUBLISHER]

We demonstrate low-density quantum dot molecules (QDMs) by selective etching using In droplets as a mask. Selective etching is performed with InGaAs QDMs buried underneath GaAs capping layer, on which In droplets are formed by droplet epitaxy using molecular beam epitaxy. During the chemical etching, the droplets act as a mask and QDMs underneath the droplets that only survive. Photoluminescence measurement from the selectively etched QDMs in mesa structures shows a much reduced intensity, which indicates low-density QDMs. This technique provides a simple and flexible method to attain low-density QDMs. The density can be easily modified by the control of the size and density of In droplets, which is suitable for single QDM spectroscopy and for their device applications. [ABSTRACT FROM PUBLISHER]