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.

Oxygen transport in brain tissue.

Abstract: Oxygen is essential to maintaining normal brain function. A large body of evidence suggests that the partial pressure of oxygen (pO(2)) in brain tissue is physiologically maintained within a narrow range in accordance with region-specific brain activity. Since the transportation of oxygen in the brain tissue is mainly driven by a diffusion process caused by a concentration gradient of oxygen from blood to cells, the spatial organization of the vascular system, in which the oxygen content is higher than in tissue, is a key factor for maintaining effective transportation. In addition, a local mechanism that controls energy demand and blood flow supply plays a critical role in moment-to-moment adjustment of tissue pO(2) in response to dynamically varying brain activity. In this review, we discuss the spatiotemporal structures of brain tissue oxygen transport in relation to local brain activity based on recent reports of tissue pO(2) measurements with polarographic oxygen microsensors in combination with simultaneous recordings of neural activity and local cerebral blood flow in anesthetized animal models. Although a physiological mechanism of oxygen level sensing and control of oxygen transport remains largely unknown, theoretical models of oxygen transport are a powerful tool for better understanding the short-term and long-term effects of local changes in oxygen demand and supply. Finally, emerging new techniques for three-dimensional imaging of the spatiotemporal dynamics of pO(2) map may enable us to provide a whole picture of how the physiological system controls the balance between demand and supply of oxygen during both normal and pathological brain activity.

Diode-pumped mode-locked Yb(3+):Lu(2)O(3) ceramic laser.

Abstract: We report a diode-pumped passively mode-locked Yb(3+):Lu(2)O(3) ceramic laser by use of a semiconductor saturable absorber mirror. Almost transform-limited 357 fs pulses at the center wavelength of 1033.5 nm with a maximum average power of 352 mW are obtained. The efficiency against the absorbed pump power is as high as 32% by use of a laser-diode pumping and the repetition rate is 97 MHz. This is the first demonstration of a diode-pumped mode-locked Yb(3+):Lu(2)O(3) ceramic laser to our knowledge.

Grain refinement in aluminum alloy 2219 during ECAP at 250 °C

Abstract: Grain refinement taking place in a coarse grained 2219 aluminum alloy deformed by equal channel angular pressing (ECAP) at a temperature of 250 °C to a strain of 12 was investigated. The microstructural changes are mainly characterized by the evolution of high density dislocation substructures with relatively low misorientations (∼3–5°) at strains below 2 and deformation bands (DBs) with moderate misorientation angle, which are frequently formed at strains above 3. Repeated ECAP leads to increasing the number and misorientation angle of the boundaries of DBs, so that the misorientation distribution for newly evolved dislocation subboundaries changes from single peak type at low strains to bimodal one at high strains. The fraction of high angle boundaries starts to increase at strain ɛ = 3, then it rapidly rises to about 80% at moderate to high strains and a new fine grains with almost random crystal orientation are fully developed in a whole material. The main mechanism of new fine grained structure formation during ECAP is discussed.

Ionic Liquids of Cationic Sandwich Complexes

Abstract: Simple cationic sandwich complexes that contained alkyl- or halogen substituents provided ionic liquids (ILs) with the bis(perfluoroalkanesulfonyl)imide anion. Ferrocenium- and cobaltocenium ILs [M(C(5)H(4)R(1))(C(5)H(4)R(2))][Tf(2)N] (M=Fe, Co) and arene-ferrocenium ILs [Fe(C(5)H(4)R(1))(C(6)H(5)R(2))][Tf(2)N] were prepared and their physical properties were investigated. A detailed comparison of their thermal properties revealed the effects of molecular symmetry and substituents on their melting points. Their viscosity increased on increasing the length of the substituent on the cation and the perfluoroalkyl chain length on the anion. Upon cooling, ILs with low viscosities exhibited crystallization, whereas those with higher viscosities tended to exhibit glass transitions. Most of these salts showed phase transitions in the solid state. A magnetic-switching phenomenon was observed for the paramagnetic ferrocenium IL, which was associated with a liquid/solid transformation, based on the magnetic anisotropy of the ferrocenium cation. (57)Fe Mossbauer spectroscopy was applied to [Fe(C(5)H(4)nBu)(2)][Tf(2)N] to investigate the vibrational behavior of the iron atom in the crystal and glassy states of the ferrocenium IL.

Teachingless spray-painting of sculptured surface by an industrial robot

Abstract: The study deals with the automatic spray-painting by a 6-DOF industrial robot equipped with an air spray gun. Since the conventional robot control command generation for the spray-painting is manually performed by skilled workers using a teaching-playback function of a robot controller, it is a time consuming and experience required process. The study aims at generating the robot control commands without any special knowledge on spray-painting, in the case of bumpers of a car as an example of sculptured surfaces. The system can automatically generate a spraying path for the air spray gun on the basis of CAD date of the workpiece, and change the spraying path into robot control commands. From experimental results, the system was found to be effective in painting bumpers of a car with uniform paint thickness.