Abstract: Disclosed are methods and systems for improving actuator performance by reducing tensile stresses in piezoelectric thin films. In one embodiment, a piezoelectric actuator includes a substrate, a first electrode positioned on the substrate, a piezoelectric thin film positioned on the first electrode, and a second electrode positioned on the piezoelectric thin film. The displacement capability of the actuator is enhanced by reducing the tensile stresses of the piezoelectric thin film. In some embodiments, a constant DC voltage applied to the piezoelectric actuator generates compressive in-plane stresses, which counteract the tensile in-plane stresses. As a result, the overall tensile stresses in the actuator are reduced, and the actuator displacement is improved.

Abstract: An energy-saving heat pump device includes first, second, third, and fourth pipes connected in sequence in a loop. A condenser is mounted between the first and second pipes. An expansion valve is mounted between the second and third pipes. An evaporator is mounted between the third and fourth pipes. A compressor is mounted between the first and fourth pipes. The compressor compresses and outputs a coolant mixture including at least two coolants. The coolant mixture in the first pipe has a pressure of 24-30 kg/cm2G and a temperature of 80-125° C. The coolant mixture produces heat while the coolant mixture passes through the condenser. A temperature of water outputted from the condenser is in a range of 45-98° C. The coolant mixture produces cold energy for a cooling medium of the evaporator while the coolant mixture passes through the second pipe, the expansion valve, the third pipe, and the evaporator.

Abstract: A heat recovery generator system (1) includes a boiler (11) converting water into high-pressure steam that passes through a steam pipe (12), a turbine (13), a first pipe (10), a condenser (15), and a second pipe (102) in sequence. The steam condenses into water after passing through the condenser (15). The condensed water passes through a water pump (16), a water supply pipe (17), and a heater (18) to the boiler (11). A latent heat recovery device (2) includes a compressor (21) that outputs a coolant moving along a coolant pipe (22) passing in sequence through a first heat exchanger device (23) and a second heat exchanger device (25) and then returning to the compressor (21). A third pipe (103) branches from the first pipe (101) and is connected to a fourth pipe (104) via the second heat exchanger device (25). The coolant absorbs heat from the steam via the second heat exchanger device (25). Heat recovery water absorbs the heat released from the coolant through the first heat exchanger device (23).

Abstract: A physiological signal sensing system and a physiological signal sensing method applied in any time and place are disclosed. The present invention is used by applying wireless transmitting electrocardiogram (ECG) data and contactless charging so as to achieve the purpose of sensing physiological signals without any time and place constraints.