Because a wearable device comprised of a flexible film should be comfortable to wear over the skin, several reports have focused on the film thickness to prepare ultrathin films that are a few micrometers or nanometers thick. [26,27] Thinning a film to this scale should realize a film capable of covering the skin asperity conformally, resulting in a good comfort while wearing and a relatively strong adhesion on skin without glue. However, ultrathin films can be difficult to handle and attach to skin. Additionally, assembling other components such as a signal processing circuit and battery without sacrificing the advantage of thickness remains challenging. Thus, many reports still employ both ultrathin film flexible devices and relatively thick films (several hundred micrometers). [1,[4][5][6][7]9,12,16,18,19,22,28] However, the effect of film thickness on sensing has yet to be discussed, although a systematical study is important to realize precise health data recordings. In addition to the wearability and film thickness depedences, biocompatibility of the sensor and film materials is another important parameter to consider for the practical application as a wearable device.In this study, we explore the dependence of the temperature change, which is measured by a printed temperature sensor fabricated on polyethylene terephthalate (PET), on thickness. A thick film was selected due to handling ease and ability to integrate other components in the future. However, some sensors such as an ECG sensor must attach onto skin with good adhesion without sacrificing conductivity, and a relatively thick flexible film itself cannot attach to skin without an adhesion layer. To create good adhesion between an ECG sensor and skin without losing conductivity, a high adhesive conductive polymer onto skin is also developed. Although gel-based electrodes are often used in medical applications, gel-based electrodes are unsuited for long-time measurements due to skin irritation. [15] Thus, we developed a gel-less sticky electrode using biocompatible materials by characterizing the adhesion, impedance between skin and the ECG sensor, and repeatability for use. Finally, as a proofof-concept demonstration, simultaneous efficient skin temperature and ECG signal recordings were conducted using a conductive polymer with an optimized film thickness. Figure 1a describes an integrated device image with a temperature sensor, an ECG sensor, an equivalent circuit between Wearable, flexible healthcare devices, which can monitor health data to predict and diagnose disease in advance, benefit society. Toward this future, various flexible and stretchable sensors as well as other components are demonstrated by arranging materials, structures, and processes. Although there are many sensor demonstrations, the fundamental characteristics such as the dependence of a temperature sensor on film thickness and the impact of adhesive for an electrocardiogram (ECG) sensor are yet to be explored in detail. In this study, the effect of film thickness for skin te...

SynopsisExperiments have been made to study the phosphorus distribution between liquid iron and the Ca0-Si02 FeOx slag equilibrated in a magnesia crucible in the temperature range 1550° to 1650°C.The phosphorus distribution ratio (P205)/[P] increased with increasing Ca0 content and decreasing temperature. The maximum value of the distribution ratio was found to be present near the slag composition saturated with the tricalcium silicate and the magnesio wustite phases. The experimentally determined phosphorus content in metal disagrees with the phosphorus contents estimated from the treatments proposed by Balajiva et al., Turkdogan and Pearson, and Hea y over the present range of slag compositions, except by Flood and Grjotheim.

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