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Resonant sensors determine a sensed parameter by measuring the resonance frequency of a resonator. For fast continuous sensing, it is desirable to operate resonant sensors in a closed-loop configuration, where a feedback loop ensures that the resonator is always actuated near its resonance frequency, so that the precision is maximized even in the presence of drifts or fluctuations of the resonance frequency. However, in a closed-loop configuration, the precision is not only determined by the resonator itself, but also by the feedback loop, even if the feedback circuit is noiseless. Therefore, to characterize the intrinsic precision of resonant sensors, the open-loop configuration is often employed. To link these measurements to the actual closed-loop performance of the resonator, it is desirable to have a relation that determines the closed-loop precision of the resonator from open-loop characterisation data. In this work, we present a methodology to estimate the closed-loop resonant sensor precision by relying only on an open-loop characterization of the resonator. The procedure is beneficial for fast performance estimation and benchmarking of resonant sensors, because it does not require actual closed-loop sensor operation, thus being independent on the particular implementation of the feedback loop. We validate the methodology experimentally by determining the closed-loop precision of a mechanical resonator from an open-loop measurement and comparing this to an actual closed-loop measurement. [ABSTRACT FROM AUTHOR]

Microelectromechanical systems (MEMS)-based sample carriers became a breakthrough for in situ inspection techniques, especially in transmission electron microscopy where the sample carrier functions as a microsized laboratory and enables dynamic studies on samples, such as nanoparticles, nanowires, lamellas, and 2-D materials. Microheaters allow for in situ manipulation of samples by applying heat stimuli such that sample properties and interactions can be studied in real time at elevated temperatures. However, currently developed microheaters still suffer from undesired effects such as mechanical deflection and limitations in temperature range, accuracy, and homogeneity. This review discusses advancements in the technological development of microheaters. Methods and results found in the literature are categorized to provide an overview of optimization methods for thermoelectromechanical design aspects. The knowledge from various application fields, including a critical reflection on mesoscopic material properties, is combined into a series of design guidelines. These compose instructions for developing and optimizing microheater characteristics, such as mechanical and thermal stress, temperature accuracy and homogeneity, power consumption, response time, and sample drift. Although this review and guide are applicable to many application fields that require a microheater, an emphasis is laid on aspects most relevant to the microheater as a high-temperature sample carrier for in situ experiments. [2017–0149] [ABSTRACT FROM PUBLISHER]