We fabricated Ni thin films on an acrylonitrile-butadiene-styrene resin (ABS) substrate using unbalanced magnetron sputtering assisted by inductively coupled plasma. In order to obtain the knowledge on the effect of ion irradiation, we investigated the gas pressure dependence on the structural and electrical properties of fabricated Ni thin films. We used a Ni target (purity of 99.95%, thickness of 5 mm and diameter of 200 mm) and used Ar gas with purity of 99.9999% as the sputtering gas. The flow rate of the Ar gas was maintained at 1 sccm. As the deposition condition, we varied the Ar gas pressure within the range of 0.3-0.8 Pa. The target DC power was constant at 400 W, radio frequency (RF) power for plasma generation was 30 W constant, thickness of the Ni thin films was constant at 200 nm. Vertical magnetic flux density to the substrate was constant at 5 mT. We measured the Ar ion emission intensity corresponding to the amount of Ar ions using emission spectroscopy of Ar plasma. The surface morphology was observed by atomic force microscopy (AFM), and the crystal structure was analyzed by X-ray diffraction (XRD). The resistivity was measured using the four point probe method. We confirmed that gas pressure affected the effect of ion irradiation. The effect of ion irradiation decreased with the increase in the gas pressure and was maximum at a gas pressure of 0.4 Pa. This suggests that controlling gas pressure is very effective for controlling the effect of ion irradiation. From the AFM images analysis, the average surface grain size of the fabricated Ni thin films surfaces decreased due to the increase in the gas pressure. From the XRD spectrum analysis, the crystallite size of the fabricated Ni thin films decreased due to the increase in gas pressure. The resistivity of the fabricated Ni thin films increased with the increase in gas pressure. The minimum resistivity of the Ni thin film was 12.1×10^-6 Ωcm at 0.4 Pa. We found that the properties of Ni thin film on an ABS resin substrate can be controlled by the effect of ion irradiation.

Recently, micro TAS (Micro Total Analysis Systems) that performs genetic testing on devices containing microfluidics has been actively studied. In micro TAS, a micro-mixer and a micro-reactor provided on a microfluidic device are driven by feeding reagents with micro-pumps. Various micro-pumps were developed and studied: e.g. displacement pumps, electro-osmotic pumps, chemically actuated micro-pumps. The diaphragm type, which is a general pump, has the problem that reagents stagnation flow on the microfluidic device due to pulsation. Focusing on gas generation technology based on photochemical reaction, we thought that gas generation by light irradiation could be used for micro-pumps. Here we reported the basic concept for the photochemical actuated micro-pump and characterized performance of the device.

Optical coherence tomography angiography has a function to visualize the blood flow of multi-layered retinal capillary plexus by layer. OCTA signals would be more utilized if they are associated with blood flow dynamics of each layer. In this study, morphological top-hat transform was applied for OCTA en face retinal images of superficial and deep layers obtained from patients of diabetic retinopathy and controls to quantify the caliber-specific flow path length. As a result, the total length of the thick flow paths in deep layer more strongly reflected the progress of retinopathy than that in superficial layer. Supposing the thick flow paths observed in deep layer OCTA as a superposition of multiple capillaries, this trend seemed to be a possible expression of partial clogs of the capillary network.