65 research outputs found
Energy Harvesting Device Using Piezoelectric Composite And Method for Manufacturing the Same
No full text본 발명은 압전재료를 폴리머 수지에 균일하게 분산시킬 수 있고, 압전효과의 시상수(time constant)를 향상시켜 고효율의 에너지 변환 성능을 얻을 수 있는 압전복합체를 이용한 에너지 변환장치 및 그 제조방법에 관한 것으로, 본 발명에 따른 에너지 변환장치는, 폴리머 수지, 압전재료 분말, 희석제, 탄소나노재료, 전도성 금속분말을 혼합한 압전복합체와; 상기 압전복합체의 상부면과 하부면에 적층되는 절연층과; 상기 압전복합체의 상부면 및 하부면과 상기 각각의 절연층 사이에 설치되어 외부의 전기장치와 전기적으로 연결되는 전극을 포함하는 것을 특징으로 한다
Neural network application overview in prediction of properties of cement-based mortar and concrete
No full textWearable and Stretchable Strain Sensors: Materials, Sensing Mechanisms, and Applications
No full textRecent advances in the design and implementation of wearable resistive, capacitive, and optical strain sensors are summarized herein. Wearable and stretchable strain sensors have received extensive research interest due to their applications in personalized healthcare, human motion detection, human–machine interfaces, soft robotics, and beyond. The disconnection of overlapped nanomaterials, reversible opening/closing of microcracks in sensing films, and alteration of the tunneling resistance have been successfully adopted to develop high-performance resistive-type sensors. On the other hand, the sensing behavior of capacitive-type and optical strain sensors is largely governed by their geometrical changes under stretching/releasing cycles. The sensor design parameters, including stretchability, sensitivity, linearity, hysteresis, and dynamic durability, are comprehensively discussed. Finally, the promising applications of wearable strain sensors are highlighted in detail. Although considerable progress has been made so far, wearable strain sensors are still in their prototype stage, and several challenges in the manufacturing of integrated and multifunctional strain sensors should be yet tackled
A 6.3 μW 20 bit Incremental Zoom-ADC with 6 ppm INL and 1 μV Offset
No full textA 20-bit incremental ADC for battery-powered sensor applications is presented. It is based on an energy-efficient zoom ADC architecture, which employs a coarse 6-bit SAR conversion followed by a fine 15-bit ΔΣ conversion. To further improve its energy efficiency, the ADC employs integrators based on cascoded dynamic inverters for extra gain and PVT tolerance. Dynamic error correction techniques such as auto-zeroing, chopping and dynamic element matching are used to achieve both low offset and high linearity. Measurements show that the ADC achieves 20-bit resolution, 6 ppm INL and 1 μV offset in a conversion timeof 40 ms, while drawing only 3.5 μA current from a 1.8 V supply. This corresponds to a state-of-the-art figure-of-merit (FoM) of 182.7 dB. The 0.35 mm² chip was fabricated in a standard 0.16 μm CMOS process.Accepted Author ManuscriptElectronic Instrumentatio
Highly Stretchable Multifunctional Wearable Devices Based on Conductive Cotton and Wool Fabrics
No full textWool fabrics decorated with carbon-based conductive ink for low-voltage heaters
No full textSmart textiles have extensively progressed in recent years and have expanded the potential scope and market of textiles, especially in areas of sensing, energy storage and heating. A great opportunity still exists to develop heaters based on natural fibre-based fabrics that are soft, light weight, and biodegradable. In this study, a simple, environmentally friendly, and scalable process to prepare highly conductive wool fabrics (CWFs) is reported. This multi-step process consists of stir coating and dip coating techniques using highly conductive ink based on graphene nanoplatelets (GNPs) and carbon black (CB) particles, followed by the cold-pressing process. Time-dependent temperature profiles and heat distribution analysis of the CWFs showed superior electrothermal performance to the heaters reported in the literature, reaching a surface temperature of more than 230 °C with a low applied voltage of 4.5 V (or an equivalent input power of ∼7.2 W). To demonstrate their potential application, the concept of a sandwich-structured and large size heating device was designed and the device was fabricated using a 3 × 3 array of CWFs
Electrical conductivity of the graphene nanoplatelets coated natural and synthetic fibres using electrophoretic deposition technique
No full textHerein, electrically conductive natural and synthetic yarns through electrophoretic deposition (EPD) technique were fabricated. A parametric study on the conductivity enhancement of the yarns is carried out by Taguchi method. Using this method, the desirable conditions are determined by studying the effects of important parameters on the electrical conductivity of the yarns in the EPD coating process. Based on the L18 design of experiments table, the preferred combination of factors to obtain the highest electrical conductivity of the yarns is found by Taguchi analysis. In addition, the Pareto ANOVA analysis is conducted to identify the major contributing factors on the electrical conductivity of the yarns. Characterisation techniques, such as scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode, and thermogravimetric analysis (TGA) are utilised for better understanding the microstructure and physical properties. When powered by only 3 V, the maximum temperature of a Joule heated conductive sample based on natural fibre yarns reached 102°C in less than 25 s
A CMOS temperature sensor with a voltage-calibrated inaccuracy of ±0.15°C (3σ) from -55 to 125°C
No full textThis paper describes an energy-efficient CMOS temperature sensor intended for use in RFID tags. The sensor achieves an inaccuracy of ±0.15°C (3σ) over the military temperature range (-55 to 125°C) and dissipates only 27nJ/conversion: over 20× less than a previous sensor with comparable accuracy and resolution [2]. This energy efficiency is achieved by the use of an improved charge-balancing scheme and a zoom ADC that combines a 5b coarse SAR conversion with a 10b fine 2 nd -order ΔΣ conversion.Accepted author manuscriptElectronic Instrumentatio
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