Reliability and mechanical durability tests of flexible OLED with ALD coating

To improve the reliability and mechanical durability of a flexible organic light‐emitting diode display, the entire flexible display is coated with an aluminum oxide film by atomic layer deposition (ALD). Because the step coverage of ALD is excellent, the AlO_x film was deposited not only on the front and back surfaces but also on the side surfaces of the display. A high‐temperature and high‐humidity preservation test, repetitive bending tests, and a pencil hardness test were conducted on the flexible display with ALD‐AlO_x coating. The display survived 500 h of a 65°C, 95% preservation test, endured a 100,000‐time repetitive bending test with a curvature radius of 4 mm, and was found to have a pencil hardness of 4H.     

Development of a flexible autonomous robot without sensors or controllers

Recently, various robots with many degrees of freedom, such as rescue robots and domestic robots, have been developed and used in practical applications. It is difficult to control such robots autonomously in real environments, because in order to control the many degrees of freedom, we have to observe many states, calculate huge amounts of information, and operate many actuators. In this study, we consider a flexible robot without sensors or controllers that can determine the inclination of a slope and climb up the slope. In order to demonstrate the effectiveness of the proposed framework, we have developed a prototype robot and conducted experiments. The result indicates that the robot could determine the inclination and climb up a gentle slope autonomously. Thus, we have realized an autonomous robot that has no explicit sensors or controllers.     

On-chip Diamond MEMS Magnetic Sensing through Multifunctionalized Magnetostrictive Thin Film

Electrically integrable, high-sensitivity, and high-reliability magnetic sensors are not yet realized at high temperatures (500 °C). In this study, an integrated on-chip single-crystal diamond (SCD) micro-electromechanical system (MEMS) magnetic transducer is demonstrated by coupling SCD with a large magnetostrictive FeGa film. The FeGa film is multifunctionalized to actuate the resonator, self-sense the external magnetic field, and electrically readout the resonance signal. The on-chip SCD MEMS transducer shows a high sensitivity of 3.2 Hz mT⁻¹ from room temperature to 500 °C and a low noise level of 9.45 nT Hz^−1/2 up to 300 °C. The minimum fluctuation of the resonance frequency is 1.9 × 10⁻⁶ at room temperature and 2.3 × 10⁻⁶ at 300 °C. An SCD MEMS resonator array with parallel electric readout is subsequently achieved, thus providing a basis for the development of magnetic image sensors. The present study facilitates the development of highly integrated on-chip MEMS resonator transducers with high performance and high thermal stability.     

Market prediction using machine learning based on social media specific features

Artificial Life and Robotics - In recent years, unspecified messages posted on social media have significantly affected the price fluctuations of online-traded products, such as stocks and virtual...     

Bounded Rationality,Group Formation and the Emergence of Trust: An Agent-Based Economic Model

Computational Economics - It is possible to model trust as an investment game, where a player in order to receive a reward or a better outcome, accepts a certain risk of defection by another...     

Revolving Vernier Mechanism Controls Size of Linear Homomultimer

A new kind of the Vernier mechanism that is able to control the size of linear assembly of DNA origami nanostructures is proposed. The mechanism is realized by mechanical design of DNA origami, which consists of a hollow cylinder and a rotatable shaft in it connected through the same scaffold. This nanostructure stacks with each other by the shape complementarity at its top and bottom surfaces of the cylinder, while the number of stacking is limited by twisting angle of the shaft. Experiments have shown that the size distribution of multimeric assembly of the origami depends on the twisting angle of the shaft; the average lengths of the multimer are decamer, hexamer, and tetramer for 0°, 10°, and 20° twist, respectively. In summary, it is possible to affect the number of polymerization by adjusting the precise shape and movability of a molecular structure.     

Modified Bagolini striated glass test: clinical applications of starlight test in binocular visual field screening

AIM: To introduce the "starlight" test which was devised to check binocular vision in normal conditions of seeing in a rapid, easy, and cost effective manner and to estimate the possibility of its clinical use in screening the binocular visual field of patients. METHOD: The Bagolini striated glass test consists of optically plano lenses with imperceptible parallel scratches that barely blur the environment but produce two perpendicular luminous stripes (right eye stripe of 45 degrees and left eye stripe of 135 degrees) when subjects with normal binocular vision view one light source. Unlike the original Bagolini test, the starlight test uses three light sources in horizontal or vertical lines according to the testing purposes and the subject is asked to fixate upon the centre light. Through Bagolini glasses, the subject observes the resulting grid-like pattern and the state of binocular visual field of the subject can be roughly estimated. RESULTS: Normal subjects and patients with strabismus, visual field loss from intracranial diseases, glaucoma, retinitis pigmentosa, and functional visual loss were examined using the starlight test and findings from each case were discussed. CONCLUSIONS: The starlight test, which was made by hand at a low cost, is a simple test that can be used clinically. It provides information about the state of binocular vision of patients in normal conditions of seeing. It is also useful because it enables the examiner to share similar experiences with the examinee. The results suggest it can be effective in visual field screening.     

Effect of temperature on humido-sensitive conducting polymer actuators

Temperature dependence of water vapor sorption and electro-active polymer actuating behavior of free-standing films made of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT/PSS) was investigated by means of sorption isotherm and electromechanical analyses. The non-porous PEDOT/PSS film, having a specific surface area of 0.13 m² g^?1, sorbed water vapor of 1080 cm³(STP) g^?1, corresponding to 87 wt%, at relative water vapor pressure of 0.95. A temperature rise from 25 °C to 40 °C lowered sorption degree, indicative of an exothermic process, where isosteric heat of sorption decreased with increasing water vapor sorption and the value reached 43.9 kJ mol^?1, being consistent with the heat of water condensation (44 kJ mol^?1). Upon application of 10 V, the film underwent contraction of 2.46% at 5 °C caused by desorption of water vapor due to Joule heating, which slightly decreased to 2.10% at 45 °C. The speed of contraction was one order of magnitude faster than that of expansion and less dependent on the temperature since water vapor sorbed in the film were forced to desorb by Joule heating. In contrast, the higher the temperature the faster the film expansion because diffusion coefficient increased as the temperature became higher.     

A biped static balance control and torque pattern learning under unknown periodic external forces

This paper addresses a biped balancing task in which an unknown external force is exerted, using the so-called ‘ankle strategy’ model. When an external force is periodic, a human adaptively maintains the balance, next learns how much force should be produced at the ankle joint from its repeatability, and finally memorized it as a motion pattern. To acquire motion patterns with balancing, we propose a control and learning method: as the control method, we adopt ground reaction force feedback to cope with an uncertain external force, while, as the learning method, we introduce a motion pattern generator that memorizes the torque pattern of the ankle joint by use of Fourier series expansion. In this learning process, the period estimation of the external force is crucial; this estimation is achieved based on local autocorrelation of joint trajectories. Computer simulations and robot experiments show effective control and learning results with respect to unknown periodic external forces.     

Semi-autonomous serially connected multi-crawler robot for search and rescue

In this paper, we develop a semi-autonomous serially connected multi-crawler robot for search and rescue. In large-scale disasters, such as earthquakes and tornadoes, the application of rescue robots to search for survivors under rubble would be beneficial. Snake-like robots (robots composed of serially connected units) are an effective candidate for such robots. Their long body enables them to overcome obstacles, and they can move into narrow spaces because of their thin shape. However, conventional snake-like robots have significant problems with operability. The numerous degrees of freedom of their bodies require complex operation to overcome obstacles, and training is required for the operators. Thus, survivors or community members cannot operate conventional robots to search for victims, despite the availability of such rescue robots. Here, we address this problem and develop a semi-autonomous serially connected multi-crawler robot designed for non-trained operators, such as community members or rescued survivors. It can be controlled easily by a conventional two-channel user interface with levers for turning and straight line motion. To demonstrate the effectiveness of our proposed mechanism, a prototype robot was developed and experiments were conducted. The results confirm that the proposed robot had both higher operability and higher mobility than conventional robots.