Eiichi Matsumoto

SQUID Nondestructive Testing System With Vibrating Normal Pick-Up Coil

A vibrating normal pick-up coil coupled to a superconducting quantum interference device (SQUID) magnetometer as a nondestructive testing system was studied. The vibrating normal pick-up coil measures the magnetic field gradient at a point. Output of the SQUID magnetometer is lock-in detected at the vibration frequency. The frequency of an excitation magnetic field can be set low to detect deep structural flaws. The use of a normal coil vibrated at 20 kHz with output voltage amplified by a low-noise amplifier enabled detection of a cylindrical defect in an aluminum plate with an excitation magnetic field at 40 Hz.

Micro-patterning of organic thin-film electronic devices by ultrashort laser

Micro-patterning of two types of organic thin-film electronic devices, an organic light emitting diode (OLED) display and an organic photovoltaic cell (OPV), are carried out using an ultrashort fiber laser. Selective machining technique of aluminium (Al) electrode of the OLED by an ultrashort fiber laser was developed and test pieces of the OLED display were fabricated successfully. It is found that the Al layer on ITO is removed by only one pulse so long as it is above its threshold energy. Similar process was applied to machining of OPV to fabricate modules in planer structure connected in series. The results indicate that selective machining of different part of OPV can be achievable using single ultrashort fiber laser. Machining conditions need to be optimized for each layer.Micro-patterning of two types of organic thin-film electronic devices, an organic light emitting diode (OLED) display and an organic photovoltaic cell (OPV), are carried out using an ultrashort fiber laser. Selective machining technique of aluminium (Al) electrode of the OLED by an ultrashort fiber laser was developed and test pieces of the OLED display were fabricated successfully. It is found that the Al layer on ITO is removed by only one pulse so long as it is above its threshold energy. Similar process was applied to machining of OPV to fabricate modules in planer structure connected in series. The results indicate that selective machining of different part of OPV can be achievable using single ultrashort fiber laser. Machining conditions need to be optimized for each layer.

Stress Intensity Factors of Annulus with Arbitrary Inner Edge Crack Subjected to Internal Pressure.

Reflected photoelasticity is applied to the problem of an annulus with an inclined crack subjected to internal pressure. The iso chromatic fringes, which are observed during experiments, are processed using an image data processing an alyzer. Thinning images are obtained for each results and the data for analysis are collected from the image. The mixed mode stress intensity factors are analyzed using sufficient data sets.