Abstract: An efficient monolithic optocoupler device that includes a photovoltaic region, an electrically isolating region, and a light emitting region deposited on a substrate in a single stack. The electrically isolating region (e.g., one or more diodes or resistive semiconductor layers) allows photons to pass from the light emitting region to the photovoltaic region while blocking electrical current between those regions. In some embodiments, the optocoupler device includes a reflector on a side of the light emitting region (opposite the photovoltaic region) that reflects photons emitted by the light emitting region back toward the photovoltaic region. The optocoupler device may also include a reflector on a side of the photovoltaic region (opposite the light emitting region) that reflects photons emitted by the light emitting region back toward the photovoltaic region. In other embodiments, the optocoupler device includes two photovoltaic regions sandwiching the light emitting region.

Abstract: A linear regulator operates in the manner of a linear voltage regulator, but with the functionality of a switching converter. This concept enables DC voltage up-conversion with no switching, more efficient step down of large voltage steps, and requires no expensive and bulky additional components. An optocoupler device transfers power between light emitting and photovoltaic devices.

Abstract: A linear regulator operates in the manner of a linear voltage regulator, but with the functionality of a switching converter. This concept enables DC voltage up-conversion with no switching, more efficient step down of large voltage steps, and requires no expensive and bulky additional components. An optocoupler device transfers power between light emitting and photovoltaic devices.

Abstract: The present disclosure provides an apparatus for forming an underground tunnel. The apparatus comprises a cutting head for removing material from a wall portion of the tunnel and thereby forming a portion of the tunnel. Further, the apparatus comprises a support structure for supporting a previously formed portion of the tunnel. The support structure is arranged to provide a supporting force against a surface of the tunnel when stationary and when being moved along the tunnel. Further, the apparatus comprises a conveyor for conveying removed material from the cutting head to a location remote from the cutting head during formation of the portion of the tunnel.

Abstract: The present disclosure provides a method for mining a material in an underground environment. The method comprises positioning a structure in an underground roadway and locating the structure so that the structure provides a reactive force when a cutting head is pushed against the material via a series of members coupled to the structure. The roadway is suitable for passage of people and transportation of machinery and removed material. The method also comprises coupling the cutting head to at least one of the members of the series of members and the series of members to the structure. Further, the method comprises forming a plurality of branch tunnel portions projecting from the roadway into the material using the cutting head and the series of members coupled to the structure, comprising repositioning the cutting head and the series of members between formation of the branch tunnel portions. At least one of the formed branch tunnel portions has a length of more than 50 m.

Abstract: A strain-balanced quantum well tunnel junction (SB-QWTJ) device. QW structures are formed from alternating quantum well and barrier layers situated between n++ and p++ layers in a tunnel junction formed on a substrate. The quantum well layers exhibit a compressive strain with respect to the substrate, while the barrier layers exhibit a tensile strain. The composition and layer thicknesses of the quantum well and barrier layers are configured so that the compressive and tensile strains in the structure are balanced.

Abstract: A strain-balanced quantum well tunnel junction (SB-QWTJ) device. QW structures are formed from alternating quantum well and barrier layers situated between n++ and p++ layers in a tunnel junction formed on a substrate. The quantum well layers exhibit a compressive strain with respect to the substrate, while the barrier layers exhibit a tensile strain. The composition and layer thicknesses of the quantum well and barrier layers are configured so that the compressive and tensile strains in the structure are balanced.

Abstract: The present disclosure provides an apparatus for forming an underground tunnel. The apparatus comprises a cutting head for removing material from a wall portion of the tunnel and thereby forming a portion of the tunnel. Further, the apparatus comprises a support structure for supporting a previously formed portion of the tunnel. The support structure is arranged to provide a supporting force against a surface of the tunnel when stationary and when being moved along the tunnel. Further, the apparatus comprises a conveyor for conveying removed material from the cutting head to a location remote from the cutting head during formation of the portion of the tunnel.

Abstract: The present disclosure provides a method for mining a material in an underground environment. The method comprises positioning a structure in an underground roadway and locating the structure so that the structure provides a reactive force when a cutting head is pushed against the material via a series of members coupled to the structure. The roadway is suitable for passage of people and transportation of machinery and removed material. The method also comprises coupling the cutting head to at least one of the members of the series of members and the series of members to the structure. Further, the method comprises forming a plurality of branch tunnel portions projecting from the roadway into the material using the cutting head and the series of members coupled to the structure, comprising repositioning the cutting head and the series of members between formation of the branch tunnel portions. At least one of the formed branch tunnel portions has a length of more than 50 m.