Measurement of the flood discharge of a small-sized river using an existing digital video recording system

In this study, a closed-circuit television (CCTV) system, installed for surveillance purposes, is utilized to measure the flow rate during a flood. The procedure to determine both the angle and scale-factor of the camera is described. Then, image analysis techniques, namely the direct visual measurement method, Large-Scale PIV (LSPIV) and Space-Time Image Velocimetry (STIV), are applied to the video images recorded by the CCTV camera. The results of these methods and the conventional float measurement are compared. In addition, the accuracy of the respective methods is discussed. A set of low-quality video images of a flood during a thunderstorm that occurred under the dark ambient conditions (midnight) is analyzed using three image-based methods. The transition of the flow rate during the event is successfully estimated.     

Development of two-dimensional mapping technique by in-air-PIXE with metal capillary

We have developed the two-dimensional mapping technique with in-air-PIXE (2D-PIXE) using a metal capillary as a guide to extract ion beam to air. The metal capillary is the conventional injection needle with a 200 μm inside diameter. For the target which is the character made of the copper wires on aluminum basement, 2D-PIXE measurements were performed by irradiating 3 MeV proton beam. As a result, the character was tend to be restored clearly by this method. We discuss about the result of the two-dimensional map from a viewpoint of the signal-to-noise ratio and the resolution. This technique is expected to be applicable to various fields such as biology, nano-technology, archeology and so on.     

The Anomalous Optical Conductivity of Metallic La2?xSrxCuO4

The in-plane optical conductivity of three metallic La_2–x Sr _x CuO₄ single crystals with 0.10 x 0.15 has been studied between 30 and 295 K. Strong peaks in the far-infrared are observed, which cannot be explained by Drude-like models. Their similarity with peaks reported in Cu–O ladders with one-dimensional charge-ordering, their extremely low frequency, and their behavior with temperature allows us to conclude that those anomalous features are excitations of charge stripes in the Cu–O planes.     

Fabrication of optics by use of plasma chemical vaporization machining with a pipe electrode

We figure optical surfaces by plasma chemical vaporization machining (CVM) with a pipe electrode, in which an rf plasma generated at the electrode tip under approximately atmospheric pressure moves over the surfaces. We propose a shaping method in which the movement of plasma on the surfaces can be determined. Flat and aspheric surfaces are successfully figured with the desired peak-to-valley shape accuracy of 0.1 microm. The root-mean-square roughness of the resultant surfaces is at the subnanometer level. These results confirm that the plasma CVM and the shaping method have the capability to fabricate optics with high accuracy.     

TEM Observations of the Initial Oxidation Stages of Nb-Ion-Implanted TiAl

Coupon specimens of TiAl were implanted with Nb ions at an acceleration voltage of 50 kV with a dose of 10²¹ ions m.^–2 They were then slightly oxidized during heating to 900 or 1200 K, or at 1200 K for 3.6 ksec (1 hr) in a flow of purified oxygen under atmospheric pressure. The implanted specimens and oxidized specimens were characterized and observed by AES, X-ray diffractometry, SEM, TEM, EDS, and EPMA. Implantation improves the oxidation resistance significantly by forming virtually -Al₂O₃ scales. The implanted layer is about 75 nm thick; the outer part of 30-nm thickness is -Ti phase and the rest of 45-nm thickness is amorphous. Heating to 900 K in O₂ results in partial crystallization of the amorphous layer to Ti₅Al₃O₂ (Z-phase) and to 1200 K results in oxide scales of 270 to 400 nm thickness consisting mainly of Al₂O₃. The fraction of Al₂O₃ in the scale increases toward the substrate. Oxidation at 1200 K for 3.6 ksec results in Al₂O₃-rich scales of about 400-nm thickness. The oxide grain size is very fine, about 80 nm in size, and becomes smaller toward the outer scale surface. This implies that implantation enhanced the nucleation of Al₂O₃ grains relative to the growth of TiO₂ grains. This finding and the formation of -Ti phase are thought to be responsible for the excellent oxidation resistance obtained.     

Effect of temperature on friction observed between a Si3N4 tip and a dodecanethiol self-assembled monolayer on Au(1 1 1)

Recent computational studies (Phys. Rev. Lett. 70 (1993) 1960; Phys. Rev. B 62 (2000) 17055) predicted that friction of ordered organic monolayer had characteristic dependence on temperature, where the maximum friction was observed around rotator transition point of the monolayer. This remained to be confirmed experimentally. Using a friction force microscope (FFM) combined with a temperature regulation module, we attempted to investigate such dependence on temperature (130 K-room temperature) on a self-assembled monolayer of dodecanethiol prepared on Au(1 1 1). The observed friction showed strong dependence on temperature and good agreement with the computational prediction.     

The road to RoboCup 2050

The ultimate goal of the RoboCup initiative is stated as follows: by mid-21st century, a team of fully autonomous humanoid robot soccer players shall win the soccer game, comply with the official rule of the FIFA, against the winner of the most recent World Cup. The authors consider this goal from the perspective of how close we are to it and what has to be done to reach it     

Impurity scattering effect on the anisotropic resistivity for La2−x Sr x CuO4−δ with a wide range of x

We have investigated the effect of the impurity scattering due to a small amount of oxygen defect, ( < 0.01) on the anisotropic resistivity of La _2–x Sr _x CuO _4– in a wide x range up to x = 0.26. In the superconducting region with 0.06 x 0.22, we found that impurity scattering by the oxygen defect remarkably decreases the c-axis resistivity c over the whole temperature range. The finding is interpreted in terms of the nonmetallic conduction along the c axis which is enhanced by scattering the confined carriers in the CuO ₂ plane. On the other hand, the enhancement of the c-axis conduction diminishes in the nonsuperconducting region. This is consistent with the two-dimensional nature of the electronic state which stabilizes the superconducting ground state in the cuprates.