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This paper describes the development of a novel technology that can form a dense and complex pattern on a polymer tube without thermal damage. We have developed an etching mask and equipment capable of processing the tubular material. We named this technology cylindrical RIE (reactive ion etching). In order to evaluate the fundamental processing characteristics of this technology, etching rate, side etching ratio and etching uniformities along the tube axis and circumferential directions are evaluated. As a result, a vertical wall caused by anisotropic etching could be observed, and the average etching rate was 1.0 µm min−1 and the average side etching ratio was 0.027. The maximum differences between etching rate along the axis and circumferential directions were 0.25 and 0.12 µm min−1, respectively. The cross-section of the etched through-groove (slit) processed in a PP (polypropylene) tube having wall thickness of 200 µm was evaluated. By the bowing phenomenon, pattern width decreased most at the middle of the thickness of the tube wall, and average width errors at the middle of the thickness was 22.4 µm. To demonstrate the usefulness of the cylindrical RIE, a stent made of PP tube was fabricated. It was possible to fabricate a stent with an outer diameter of 4.4 mm, length of 19 mm, main strut width of 300 µm, and connecting strut width of 80 µm.

In recent years, in order to meet the demand for maintenance free batteries a sealed lead-acid battery has been taking the place of a flooded lead-acid battery and becoming widespread for use as a stationary type lead-acid battery for telecommunication.As a conventional means of determining the life of a flooded leadacid battery, measurement of specific gravity and visual check of the battery outside appearance have been performed. However, in a sealed lead-acid battery, this conventional method can not be used, and troublesome capacity testing and cell voltage monitoring have therefore been the only means to obtain information about battery deterioration.To determine the life of this sealed lead-acid battery, we paid attention to its internal impedance and limited our research to the life mode in a condition of floating charge that is usually used, and we have now developed a device capable of determining and displaying the battery life without disconnecting the load from the battery.

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