University of Electro-Communications

About: University of Electro-Communications is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Laser & Robot. The organization has 8041 authors who have published 16950 publications receiving 235832 citations. The organization is also known as: UEC & Denki-Tsūshin Daigaku.

Mechanical Properties of Magnesium Alloy AZ31 after Severe Plastic Deformation

Abstract: Grain refinement of magnesium alloy AZ31 was studied in multidirectional forging (MDF) under decreasing temperature conditions. MDF was carried out up to large cumulative strains of 5.6 with changing the loading direction during decrease in temperature from pass to pass. MDF can accelerate the uniform development of very fine- grained structures and an increase of the plastic workability at low temperatures. New grain structures with the minimal grain size of 0.23 μm can be developed by continuous dynamic recrystallization at a final processing temperature of 403 K. As a result, the multidirectional- forged alloy showed excellent higher strength as well as moderate ductility at room temperature, and also a superplastic elongation of over 300% at 423 K. The mechanisms of strain-induced and fine-grained structure development and of the excellent plastic deformation are discussed in detail.

New data on the physical properties of Y3Al5O12-based nanocrystalline laser ceramics

Abstract: Microhardness and fracture toughness of highly transparent Y3Al5O12-and Y3Al5O12: Nd3+-based nanocrystalline ceramics are measured for the first time. For the Y3Al5O12: Nd3+ laser ceramics, the use of a longitudinal scheme with a diode-laser pumping at a wavelength of 1.3186 mm (4 F 3/2 → 4 I 13/2 channel) enabled one to attain an output power of continuous-wave lasing of ∼3.7 W with 35% efficiency.

Near-infrared noninvasive blood glucose prediction without using multivariate analyses: introduction of imaginary spectra due to scattering change in the skin

Abstract: A noninvasive measurement method is proposed and examined to continuously predict blood glucose contents using near-infrared diffuse reflection difference spectra measured at the skin tissue without using multivariate analyses. Using the modified Beer’s law, the difference spectra are assumed to be synthesized from four major components in the human skin (water, protein, glucose, and fat) and a scattering equivalent component called baseline. As a result, one of the origins of the errors in blood glucose prediction using near-infrared is found to be the similarity of the shapes of the absorption spectrum between glucose and baseline. After separating the glucose contributions from the difference spectra at the characteristic wavelengths of baseline and fat, an imaginary component combining baseline and fat is introduced by considering that both the change in the fat contribution and the generation of baseline originate from the change in scattering in the skin. The imaginary component enables us to reduce the errors in blood glucose prediction. In contrast to the methods using multivariate analyses, the calculation process of the blood glucose contents from the measured reflection spectra is clear in this method, thus, it is easy to estimate the origins of the changes and contributions of the components in the measured difference spectra. The proposed method may become a useful tool for realization of noninvasive blood glucose prediction using near-infrared spectroscopy.

Multi-axial micromanipulation organized by versatile micro robots and micro tweezers

Abstract: In this paper, we describe development of the multi-axial micromanipulation organized by versatile micro robots using micro tweezers. To conduct microscopic operations, a unique locomotion mechanism composed of four piezoelectric actuators and two electromagnets is proposed. Here two legs arranged to cross each other are connected by four piezoelectric actuators so that the robot can move in any direction, i.e. in X and Y directions as well as rotate at the specified point precisely in the manner of an inchworm. To manipulate micro objects by these versatile micro robots, we have developed micro tweezers driven by 3 piezoelectric actuators. We have also developed an electromagnetic spherical micromanipulator to position the micro tweezers. The electromagnetic spherical micromanipulator rotates in yaw, roll and pitch directions independently. The electromagnetic spherical micromanipulator is a 1-inch cube size, so we can easily attach them on top of the versatile micro robots. We have developed the multi-axial micromanipulation organized by 3 versatile micro robots with the electromagnetic spherical micromanipulator and micro tweezers. The whole manipulation device is very small, 200 mm in diameter and 70 mm in height, so we can easily attach the device to micro processing instruments even if the working area is very small. This device has 21 DOF with less than 100 nm resolution. In experiments, we have demonstrated flexible handling of miniscule glass spheres with a diameter of 20 mum. We have also succeeded in fixing miniscule glass spheres on a sample table by an ultraviolet cure adhesive. The design procedure, basic performance and micro-assembling applications of this tiny robot are also discussed as part of the new field of micro robotics requiring especially high precision in certain regions.

Reflection-type hologram for atoms.

Abstract: A cold metastable neon atomic beam was manipulated with a reflective amplitude hologram that was encoded on a silicon surface. A black-and-white pattern of atoms was reconstructed on a microchannel plate detector. The hologram used the enhanced quantum reflection developed by authors and was made of a two-dimensional array of rectangular low and high reflective cells. The surface of the high reflective cell was composed of regularly spaced roof-shaped ridges, while the low reflective cell was simply a flat surface. The hologram was the first demonstration of reflective atom-optical elements that used universal interaction between a neutral atom and solid surface.