We demonstrated the fabrication of thermoelectric sensors and D-glucose sensors using femtosecond laser pulse-induced photothermochemical reduction. Thermoelectric sensors which composed of Cu (p-type) and Cu-Ni (n-type) patterns were fabricated using glyoxylic acid Cu complex ink and glyoxylic acid Cu/Ni mixed complex ink, respectively. When the concentration of Ni was 40 at.%, Seebeck coefficient of the Cu-Ni pattern was -38μV/K, which was consistent with the films deposited by general vacuum deposition methods. D-glucose was detected using Cu-rich electrodes which were fabricated using a CuO nanoparticle ink. The CuO nanoparticle ink, which composed of CuO nanoparticles, ethylene glycol as a reducing agent, and polyvinylpyrrolidone as a dispersant, was irradiated on glass substrates by femtosecond laser pulses. Cu-rich electrodes exhibited linear detection properties of D-glucose. In addition, the selectivity of Cu-rich electrodes towards 100μM D-glucose detection was high in the presence of 20μM-4 acetamidophenol, 20μM-uric acid, and 20μM-ascorbic acid in 0.1M-NaOH solution.

Laser micro texturing has the effect of increasing the coefficient of friction between metals by imparting fine surface irregularities. This paper describes some examples of micro texturing and outlines the effect of micro texturing. In the case of a titanium alloy textured with micro-texturing, the micro-patterns promoted titanium adhesion and increased the static coefficient of friction by a factor of 2.8. The reason for this increase in static friction can be attributed to the effective release of metal oxides, which have the effect of reducing friction. It is important to verify the effectiveness of the method in the presence of oily agents in the future.

Multi-scale texturing and surface modification have the potential to develop higher functions and new functions. As a method for efficiently creating a fine structure, laser-induced periodic surface structure (LIPSS) is attracting attention which is a periodic nanostructure with the periodicity depending on the laser wavelength fabricated in a self-organized manner by ultrashort-pulsed laser ablation on a material surface. It has been reported that LIPSS can control the tribology, wettability and optical properties. However, the functions of LIPSS are limited since the geometry of LIPSS depends on the pulse duration, wavelength and material. Therefore, we developed methods to utilize other processing processes for ultrashort-pulsed laser processing to control nanostructures, fabricate hybrid structures and modify the material surface. The ultra-precision cutting assisted ultrashort-pulsed laser was able to improve the straightness, uniformity, and aspect ratio of LIPSS by promotion of surface plasmons, and to create multiscale structures. Moreover, by compositing electrochemical machining, multi-scale structures can be created with improving the machining efficiency due to the increase of the electric field intensity, and the microstructure can be created while controlling the surface composition.

Surface modification technology is applied in various situations, and it is a method that can be made into a multi-material by coating the material with different materials. For example, a tough metal can be coated with a high hardness material, or the coating material itself can be combined to have multiple functions. Among them, wear-resistant coating used at high temperature is an indispensable technique for extending the life of industrial members and requires multiple performances. One of the surface modification methods Laser Metal Deposition (LMD) can control input energy precisely. Because of this, heat inputs reduced, and show high functionality of coating.This report describes LMD technology and use cases.

Laser processing has been one of the major applications of lasers since they were developed in 1960s because it has remarkable advantages compared with other processing methods. There are many types of the processing methods with lasers, that is, cutting, drilling, welding, texturing, thin-film processing, etc. The methods have been applied to process many materials, for example metals, polymers, glass, semiconductors and so on. Polymers are also used in many fields because of easy processing, lightness in weight, and insulating. In this literature, laser processing of polymer materials are explained in terms of the processing methods.

Laser-induced wet surface treatment method has been developed as new surface modification method, which was developed with low energy. Laser irradiation on austenitic stainless steel soaked in Al (NO₃)₃aqueous solution generated the treated layer containing Al and O derived from the solution. The hard treated layer improved sliding characteristics and wear resistance. In order to modify structures with more complicated shapes, the method of supplying solution as mist for generation of treated layer has also been proposed. This method provided treated layer similar performance to the soaking method.

Efforts to elucidate the rolling contact fatigue of rails are being vigorously implemented in Japan and overseas. The X-ray diffraction line profile analysis is expected as a method for quantitatively evaluating the strain of a material, but there are few examples of its application to practical materials. In order to establish this method as a useful method for quantifying the effect of rolling contact of rails, it is necessary to experimentally clarify basic matters such as the correlation between the analysis result and the degree of rolling contact fatigue. In this study, a twin-disc test was conducted using a rail steel test piece. The purpose of the twin-disc test is to prepare test pieces with different degrees of rolling contact fatigue. The degree of rolling contact fatigue of each test piece was evaluated by the tendency of crack generation and the depth of the plastic flow by observing the metallographic structure. Furthermore, the X-ray diffraction line profile analysis was performed on each test piece to understand the correlation between the results.

A grease is a semi-fluid dispersion of a thickener in a base oil. Thickener fibers form a network disperses as fiber in grease forming a network structure, and the base oil is likely kept in the thickener network by capillary force. Grease structure has been commonly modeled based on thickener fibers observed by TEM. The thickener fibers and the bulk grease can cover a wide range of size from nm to µm and µm to mm, respectively. Therefore, a detailed understanding of grease structure may necessitate complex observation techniques including visual inspection, optical microscopy (OM) and electron microscopy (TEM or SEM). Although thickener fibers can hardly be observed by OM, the use of confocal laser fluorescence microscopy (CLFM) in this work enabled a close observation of the fibers and proved a three-dimensional grease structure. The author’s CLFM, and TEM SEM, observations revealed a hierarchical structure of grease, which is formed as follows from low to high levels: fibrils assemble to compose fibers, and a mix of fibrils and fibers composes the network. Incorporating the results into the conventional model, hierarchical 2D and 3D models of grease structure were suggested.