A shape memory circuit breaker includes a shape memory substrate having first and second opposed substrate ends. The shape memory substrate is configured to transition from a strained conductive configuration to a fractured non-conductive configuration. An isolation housing is coupled with the shape memory substrate. The isolation housing includes first and second anchors coupled near the first and second substrate ends. A brace extends between the first and second anchors, and the brace statically positions the first and second anchors and the respective first and second substrate ends. The shape memory substrate is configured to transition from the strained conductive configuration to the fractured non-conductive configuration at or above a specified temperature range corresponding to a specified overload current range or voltage range, and the first substrate end fractures from the second substrate end at or above the specified temperature range resulting in an open circuit.

Certain aspects are directed to a thermal fuse for preventing overheating of RF devices in a telecommunication system. In one embodiment, an RF thermal fuse comprises a body: a conductive bolt positioned in the body, the conductive bolt having a length sufficient to provide an impedance at a point of protection on a transmission line in response to the conductive bolt contacting a live conductor of the transmission line, wherein the impedance reflects a portion of the incident power of an RF signal from an RF signal source; and a driving mechanism that causes the conductive bolt to selectively contact the live conductor in response to an event.

Certain aspects are directed to a thermal fuse for preventing overheating of RF devices in a telecommunication system. In one embodiment, an RF thermal fuse comprises a body: a conductive bolt positioned in the body, the conductive bolt having a length sufficient to provide an impedance at a point of protection on a transmission line in response to the conductive bolt contacting a live conductor of the transmission line, wherein the impedance reflects a portion of the incident power of an RF signal from an RF signal source; and a driving mechanism that causes the conductive bolt to selectively contact the live conductor in response to an event.

A temperature-sensitive pellet type thermal fuse is disclosed. The thermal fuse comprises a metal case (10); a first lead wire (L1) fixedly installed on an open end of the case (10) to be insulated from the case (10) by an insulating bushing (20); a second lead wire (L2) electrically connected to the bottom wall (12) of the case (10); a temperature-sensitive pellet (12) installed inside the case (10); a movable terminal (60) being in contact with the fixed contact point (L2a) of the second lead wire (L2) and with the fixed terminal (40) below a fuse cutoff operation temperature, and being in contact with the case (10) but separated from the fixed contact point (L2a) of the second lead wire (L2) above the fuse cutoff operation temperature; a fixed terminal (40) having a through hole (41) with an inner wall, and being fixed on an inner wall (11) of the case; and the movable terminal (60) having a movable contact element (50) slidably contacting with the inner wall of the through hole (41) of the fixed terminal (40) to electrically connect to the fixed terminal (40).

Zero power wireless sensors, devices, and systems are used for crop water content monitoring. The sensors consume no power while monitoring for the presence of dry crop conditions. Infrared reflectance from plants is measured and when selected spectral conditions are met, a circuit is closed, activating an alarm, an RFID tag, or a radio transmitter. The deployed sensors consume no power while monitoring, reducing or eliminating the need to change batteries.

A laser remote control switching system comprises a laser source and a control circuit. The control circuit comprises a power, an electronic device, a first electrode, a second electrode, and a photosensitive element electrically connected in sequence to form a loop. Each of the two nanofiber actuators comprises a composite structure and a vanadium dioxide layer. The composite structure comprises a carbon nanotube wire and an aluminum oxide layer. The aluminum oxide layer is coated on a surface of the carbon nanotube wire, and the aluminum oxide layer and the carbon nanotube wire are located coaxially with each other. The vanadium dioxide layer is coated on a surface of the composite structure, and the vanadium dioxide layer and the composite structure are located non-coaxially with each other.

A laser remote control switching system comprises a laser source and a control circuit. The control circuit comprises a power, an electronic device, a first electrode, a second electrode, and a photosensitive element electrically connected in sequence to form a loop. Each of the two nanofiber actuators comprises a composite structure and a vanadium dioxide layer. The composite structure comprises a carbon nanotube wire and an aluminum oxide layer. The aluminum oxide layer is coated on a surface of the carbon nanotube wire, and the aluminum oxide layer and the carbon nanotube wire are located coaxially with each other. The vanadium dioxide layer is coated on a surface of the composite structure, and the vanadium dioxide layer and the composite structure are located non-coaxially with each other.

An electric power system such as, for example, a circuit, an electric appliance, an electric generator, and/or an energy storage system, can be coupled with a negative thermal expansion component. The negative thermal expansion component can be formed from a material having negative thermal expansion properties such that the negative thermal expansion component contracts in response to an increase in temperature. The contraction of the negative thermal expansion component can form a nonconductive gap that disrupts current flow through the electric power system. The disruption of the current flow can eliminate hazards associated with the electric power system overcharging, overheating, and/or developing an internal short circuit.

An electric power system such as, for example, a circuit, an electric appliance, an electric generator, and/or an energy storage system, can be coupled with a negative thermal expansion component. The negative thermal expansion component can be formed from a material having negative thermal expansion properties such that the negative thermal expansion component contracts in response to an increase in temperature. The contraction of the negative thermal expansion component can form a nonconductive gap that disrupts current flow through the electric power system. The disruption of the current flow can eliminate hazards associated with the electric power system overcharging, overheating, and/or developing an internal short circuit.

An electric power system such as, for example, a circuit, an electric appliance, an electric generator, and/or an energy storage system, can be coupled with a negative thermal expansion component. The negative thermal expansion component can be formed from a material having negative thermal expansion properties such that the negative thermal expansion component contracts in response to an increase in temperature. The contraction of the negative thermal expansion component can form a nonconductive gap that disrupts current flow through the electric power system. The disruption of the current flow can eliminate hazards associated with the electric power system overcharging, overheating, and/or developing an internal short circuit.