This paper describes the influence of Na₂SO₄-electrolytic reduced water (hereinafter referred to as ER water) on pure aluminum. First, the etching action of Na₂SO₄ ER water on the surface of pure aluminum was clarified by the etching test using immersion. The comparative study showed that Na₂SO₄ ER water was superior to chemical solution or Na₂SO₄-electrolytic oxidizing water in etching action, and the stronger electrolytic current value becomes, the stronger the etching action of Na₂SO₄ ER water becomes. Next, by the observation using FE-SEM image, the influence of Na₂SO₄ ER water on the micro shape of the surface of pure aluminum was clarified. The results showed there was not a difference between the micro shape of the sample piece done by Na₂SO₄ ER water and the one done by NaOH solution, and even in either case the alien substance appears on the surface of sample pieces. Lastly, by analyzing the surface using EDS, the influence of Na₂SO₄ ER water on the chemical composition of the surface of sample pieces was clarified. The results showed Na₂SO₄ ER water and NaOH solution are similar level. By this study, we received the suggestion that Na₂SO₄ ER water could be applied to the surface treatment such as the etching of pure aluminum.

Plasma nitriding was carried out on austenitic stainless steel (SUS304) by a low power electron beam induced plasma source. The electron beam, a function of the electron energy and beam current, is independently controlled. Besides, the apparatus incorporates a grid-type electrode that repels the ions but allows neutral particles to reach the workpiece surface. The nitriding process was done in 25% N₂, 50% H₂, and 25% Ar gas delivery at a working pressure of 0.5 Pa. The treatment time was 3 hours under 350°C, 400°C, and 450°C processing temperatures. The results of our experiments show that at lower processing temperatures of 350 and 400°C, the formation of the expanded austenite lattice (S-phase) was confirmed by x-ray diffraction (XRD) and micrographs of the etched cross-sections, respectively. The measurements of the S-phase layer show increased hardness distribution and higher corrosion resistance compared to that of the untreated austenitic stainless steel. On the other hand, the measured surface roughness at 350°C and 400°C were RMS values of 15nm and 25nm, respectively compared to 7nm for the untreated surface. This shows that the controlled plasma nitriding system was an effective and beneficial method for treating high precision mechanical components that need to retain the mirror-finish after plasma nitriding the preferred austenitic stainless steel.

Our research introduced a 40kHz thrust force directional vibration-assisted ductile-mode grinding of hard and brittle materials. And, the vibration-assisted grinding was adopted in order to avoid brittle fracture on the ground surface. But, the cause of this result could not be proved, because it was difficult to investigate removal process by many and various abrasive grains. Therefore, this study describes an evaluation of ductile-brittle transition with thrust force directional vibration-assisted cutting. Because the movement of cutting tool edge is similar to that of a grain on grinding wheel with the vibration. Then, cutting tool is oscillated by Fast Tool Servo actuator, and the frequency 1.00 kHz and amplitude 1.33 µm. In this cutting process, some intermittent cutting marks occur in the sub-micron depth. The rake angle of diamond tool is -35 and -65 degrees. Workpiece is synthetic silica glass. As an experimental result, the vibration-assisted cutting of the silica glass has a larger ductile-mode surface at removal depth of cut 0.09-0.15μm. And, it guessed that this increase of ductile-mode surface is affected by plastic flow of the workpiece under the tool, and ease of cut into workpiece by movement of cutting tool.

In recent years, the need for piping inspection has been increasing, and various in-pipe inspection robots have been studied and developed by several research and educational institutes and companies so far. However, there are few verification examples of moving mechanisms considering the run-through performance of pipe fitting (bent pipes and branch pipes).

We have proposed an omnidirectional mobile mechanism for pipe-inspection robot in small diameter pipes. A movement control method in the pipe by omnidirectional movement mechanism equipped with four independent rotary wheels has been discussed. It was shown that the approach of movement control of vehicles was applicable. The straight, spiral and rotary movements can be confirmed by modeling of the omnidirectional mechanism and simulation using proposed method.

Automatic image captioning has various important applications such as the depiction of contents for the visually impaired. Most approaches use Deep Learning and have achieved remarkable results. However there are still some unresolved issues. One of them is the overfitting of the trained model to specific images, usually caused by limited training dataset sizes. In order to augment the training dataset size in such scenarios, previous researches proposed data augmentation using random cropping or mask. However, those do not specifically target overfitted regions in images and, therefore, may remove areas in images that are needed to generate captions and lower performance. In this study, we propose a novel data augmentation method that targets specifically regions in images subject to overfitting by using attention. Experimental results show that the proposed method allows generation of better image captions.

Laser scanning systems for laser micro drilling and optical inter-satellite communication have required fast steering mirrors (FSMs) with a large diameter. However, increasing the mirror diameter makes the fast positioning more difficult because the elastic mode of the mirror occurs at a lower frequency. To solve the problem, a segmented FSM, in which several small mirror actuators having higher natural frequencies work together to produce the same reflective surface as a large mirror generates, is proposed. The final target of this research is to achieve a bandwidth of 10 kHz and more with a reflective surface of 50 mm in diameter. For the verification of the feasibility, a multi-axis, high response and small mirror actuator having a single hexagonal mirror with a distance between opposite sides of 18 mm was designed and tested. Each small mirror made of SiC is driven by a combination of tip-tilt and piston drivers using piezoelectric actuators. The fabricated small mirror actuator realized the first natural frequency over 10 kHz. The prototype is tested by a feedback controller with integrators and notch filters. The designed controller achieved the target bandwidths of 10 kHz in all the driving directions.