Analysis of structure characteristics in laminated graphene oxide nanocomposites using molecular dynamics simulation

The characteristics of laminated graphene oxide (LGO) nanocomposite, which are expected to be used for highly functional composites, are known to be related to its microstructure. In this study, we investigate the influences of hydrogen-bonding and cross-linked network structures on the initial stiffness and yield stress, using molecular dynamics simulations. Our results show that each structure increases the mechanical properties, and the combination of these structures strengthens the properties. Moreover, we found that the physical origin of the enhancement is cross-linked networks that generate stretched polymers connecting graphene sheets. Our study concludes by suggesting an appropriate selection of materials for high-performance LGO nanocomposites.     

Neural substrates involved in the control of posture

Abstract

This review argues neuronal mechanisms of postural control. Multi-sensory information such as somatosensory, visual, and vestibular sensation act on various areas of the brain so that adaptable postural control can be achieved. Automatic process of postural control, which is termed as postural reflexes including head–eye coordination accompanied by appropriate alignment of body segments, is mediated by the descending pathways from the brainstem. Cooperation of the vestibulospinal, reticulospinal, and tectospinal tracts contributes to this process. On the other hand, walking in unfamiliar circumstance requires cognitive process of postural control, which depends on knowledge of self-body, such as body schema, sense of postural verticality, and body motion in space. Such a bodily cognitive information is produced at the temporoparietal cortex. They are fundamental to sustention of vertical posture and construction of motor programs. The programs then run to execute anticipatory postural adjustment which is appropriate for achievement of goal-directed movements. The basal ganglia and cerebellum may affect both the automatic and cognitive processes of postural control through reciprocal connections with the brainstem and cerebral cortex, respectively. Consequently, impairments in cognitive function in addition to damages in the motor cortex, basal ganglia, and cerebellum may disturb appropriate postural control, resulting in falling.     

IR tag detection and tracking with omnidirectional camera using track-before-detect particle filter

Robust user detection and tracking is one of the key issues for a personal robot to follow the target person. In this paper, a novel tracking system using an omnidirectional camera and IR LED tags is proposed. The users wear the tags on their ankles, and the tags emit a light pattern as its ID. The camera on the robot is used to detect and track their positions individually. A novel approach based on a track-before-detect particle filter is proposed. It detects and tracks the tags simultaneously, even if the tags are not synchronized with the camera sampling or are not fully observable. The effectiveness of the proposed system is evaluated by experiments using a prototype personal robot.     

超分辨光盘中应用的判决反馈部分响应最大似然

一、引言对于超过衍射极限的超分辨光盘研究,已经有了可观的进展。对于双倍密度蓝光光盘,这些光盘的信噪比是足够的。但是,实际系统中得到的误码率,以50G的光盘制造来     

STDP provides the substrate for igniting synfire chains by spatiotemporal input patterns

Spike-timing-dependent synaptic plasticity (STDP), which depends on the temporal difference between pre- and postsynaptic action potentials, is observed in the cortices and hippocampus. Although several theoretical and experimental studies have revealed its fundamental aspects, its functional role remains unclear. To examine how an input spatiotemporal spike pattern is altered by STDP, we observed the output spike patterns of a spiking neural network model with an asymmetrical STDP rule when the input spatiotemporal pattern is repeatedly applied. The spiking neural network comprises excitatory and inhibitory neurons that exhibit local interactions. Numerical experiments show that the spiking neural network generates a single global synchrony whose relative timing depends on the input spatiotemporal pattern and the neural network structure. This result implies that the spiking neural network learns the transformation from spatiotemporal to temporal information. In the literature, the origin of the synfire chain has not been sufficiently focused on. Our results indicate that spiking neural networks with STDP can ignite synfire chains in the cortices.     

Minimization of maximum failure criterion of laminated composite shell structure by optimizing distributed-material orientation

Structural and Multidisciplinary Optimization - In this study, we propose a distributed-parameter optimization method for the material-orientation design aiming at maximizing the strength of a...     

Development of microparticle counting sensor based on structural and spectroscopic properties of metal mesh device

A microparticle counter based on a metal mesh device was developed. The metal mesh device had a lattice-shaped structure with well-regulated holes of 1.8 μm. The collection percentages of differently sized microparticles using the metal mesh device were determined by flow cytometry. The cut-off point and hole size of the metal mesh device were identical. Polystyrene microparticles were detected from changes in the spectroscopic properties of the metal mesh device. When microparticles were trapped on the holes of the metal mesh device, the transmittance in the infrared spectra decreased. Microparticles smaller than the holes were not detected by the metal mesh device, whereas 2 and 3 μm microparticles were detected. Polystyrene and silica microparticles could be counted using the metal mesh device via calibration curves between the concentration of microparticles and the change level in the transmittance of the metal mesh device. The separation of microparticles from a mixture suspension using the metal mesh device was evaluated. Unlike a microfiber filter, only 2 μm microparticles were collected from coexisting 1 μm microparticles by the metal mesh device. Owing to its high separation ability, the metal mesh device selectively detected 2 μm microparticles in coexisting 10-equivalence 1 μm microparticles.     

Interruptibility Estimation Based on Head Motion and PC Operation

Frequent and uncontrolled interruptions by information systems that do not reflect the user’s state can result in fragmented working times and decreased intellectual productivity. To avoid adverse interruptions, interruptibility estimation methods based on PC operation information have been proposed. However, workers who use PCs to accomplish their primary tasks occasionally engage in paperwork. Occasional paperwork activities, which are not reflected in the PC’s operation information, can cause estimation errors. This study focuses on using the position of the head, posture, temporal motion, and continuity of the head position and posture while a worker is at his or her desk as indices to reflect engagement in the task at hand. Based on an analysis of the relationship between the head-related parameters and interruptibility, an interruptibility estimation algorithm is proposed using four head-related indices that reflect interruptibility during PC and non-PC work. Experiments indicate that estimation accuracy improves as a result of incorporating these indices in the algorithm.     

Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application

We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al(2)O(3)) capillary to guide a 10(16)-W/cm(2) ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 × 10(18) cm(-3). Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation.     

Simple Salt‐Coordinated n‐Type Nanocarbon Materials Stable in Air

After more than three decades of molecular and carbon‐based electronics, the creation of air‐ and thermally stable n‐type materials remains a challenge in the development of future p/n junction devices such as solar cells and thermoelectric modules. Here a series of ordinary salts are reported such as sodium chloride (NaCl), sodium hydroxide (NaOH), and potassium hydroxide (KOH) with crown ethers as new doping reagents for converting single‐walled carbon nanotubes to stable n‐type materials. Thermoelectric analyses reveal that these new n‐type single‐walled carbon nanotubes display remarkable air stability even at 100 °C for more than 1 month. Their thermoelectric properties with a dimensionless figure‐of‐merit (ZT) of 0.1 make these new n‐type single‐walled carbon nanotubes a most promising candidate for future n‐type carbon‐based thermoelectric materials.