We used SU-8 shrinkage to fabricate strained graphene resonators to produce a high quality factor in a graphene resonator. A-few-layer graphene resonators were fabricated on a trench of an SU-8 resist. These resonators were clamped with diamond-like carbon (DLC), which was deposited by using focused-ion-beam chemical vapor deposition (FIB-CVD), and trimmed by using FIB etching. Annealing was used to apply tensile strain to the graphene resonators because SU-8 shrinks drastically. We also observed an increase in resonant frequency and quality factor in these graphene resonators after annealing. At room temperature, the quality factor of the best sample exceeded 7,000 for a resonator length of 10 µm.

Continuous monitoring of eating habits could be useful in preventing lifestyle diseases such as metabolic syndrome. Conventional methods consist of self-reporting and calculating mastication frequency based on the myoelectric potential of the masseter muscle. Both these methods are significant burdens for the user. We developed a non-invasive, wearable sensing system that can record eating habits over a long period of time in daily life. Our sensing system is composed of two bone conduction microphones placed in the ears that send internal body sound data to a portable IC recorder. Applying frequency spectrum analysis on the collected sound data, we could not only count the number of mastications during eating, but also accurately differentiate between eating, drinking, and speaking activities. This information can be used to evaluate the regularity of meals. Moreover, we were able to analyze sound features to classify the types of foods eaten by food texture.

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