摘要:
Invasive devices, such as laser fiber guides and biopsy needles, constructed of a material which exhibits little or no magnetic susceptibility, have a flexible polymer coating for retaining pieces of the device in the event of a fracture of the invasive device. The polymer coating also allows removal of the pieces of a fractured invasive device from the body of a subject without requiring surgery. The surgical instruments can be used inside a magnetic field during magnetic resonance (MR) imaging, thereby allowing interactive internal images to be produced and displayed to a surgeon during surgery. Since the invasive devices exhibit low susceptibility, they do not distort a created MR image.
摘要:
A battery exposed to heating from incident sunlight is cooled by rejecting heat to air drawn through a chimney by the heating of at least portions of the chimney by the incident sunlight. The battery is placed within the chimney so that the air flow in the chimney passes around the battery, enabling heat to be transferred directly from the battery to the air. Air flow in the chimney is generated by sunlight incident on the exterior of the chimney, causing heating of air within at least a portion of the chimney to create a natural convective air flow within the chimney, with relatively cool outside ambient air being drawn in at one end of the chimney and heated air being exhausted out the other end of the chimney.
摘要:
A method for fabricating incandescent lamp filaments having surface features of submicron-to-micron sized cross sections which increase the radiative efficiency of the filament comprises depositing at least one enveloping mask layer on the filament and cutting a selected pattern into the filament by ablation with a beam of radiated energy. The desired surface features are formed on the filament by a process that includes stenciling through the selected pattern.
摘要:
An electrical-energy-supplying device having an extended storage life includes a finned heat sink; a battery for supplying electrical energy is thermally connected to the finned heat sink by a copper or aluminum bar for transferring heat from the battery to the heat sink. The heat sink is enclosed in a chimney structure which has an air inlet in a lower portion and an outlet in an upper portion thereof. The chimney lower portion has a heat and light absorbing coating which causes air to flow in a path between the air inlet and outlet by convention. The heat sink is positioned in the air flow path the facilitate heat dissipation from the sink to the atmosphere. The storage life of the battery may be extended by maintaining the battery temperature below a selected temperature level.
摘要:
A tubular varistor arrangement, particularly suitable for use in electrical connectors of circular cross-section, attains an electrical breakdown voltage equalling the cumulation of the breakdown voltages of multiple varistor sections of the arrangement. The varistor arrangement includes a plurality of tubular varistor sections that are interconnected in electrical serial relationship.
摘要:
Thermal processing of selected areas of a workpiece, such as a semiconductor device, is implemented without a photolithographic masking step. This is achieved through the use of a pulse-mode source of heat energy, such as a laser or a particle beam source, the heat radiation of which is applied in blanket fashion to a workpiece. Selective heating of workpiece areas to be thermally processed is attained through appropriate selection of energy, pulse duration, and pulse interval operating parameters of the heat source. Specifically, the appropriate selection of heat energy defines which areas of a workpiece are to be selectively heated, while the appropriate selection of heat energy pulse duration and heat energy pulse interval minimizes stray heat transfer to non-selected areas of the workpiece.
摘要:
A bismuth-free, zinc oxide based varistor exhibits a controllable overshoot/undershoot voltage characteristic. The varistor is composed of zinc oxide as the primary constituent, with smaller quantities of barium, boron, one or more transition elements and aluminum. Varistor voltage versus time response is dependent on the degree of aluminum doping. Typically, more than approximately 0.003 mole percent, but less than approximately 0.1 mole percent aluminum is employed, depending on desired voltage overshoot/undershoot characteristic.
摘要:
A light source (10) includes a light emitting component (32), such as a UV/blue light emitting diode or laser diode, a layer (46) of a light scattering material (42), and a layer (48) of a phosphor material (44). The phosphor material converts a portion of the light emitted by the light emitting component to light of a longer wavelength, such as yellow light. The scattering material scatters the light emitted by the light emitting component and/or the light converted by the phosphor to improve the overall uniformity of the angular distribution of the light. When combined, the converted and scattered light has a more uniform angular distribution, that is, it maintains the approximately the same color as the viewing angle is changed.
摘要:
A current limiting device utilizing an electrically conductive composite material and an inhomogeneous distribution of resistance structure is disclosed. The inhomogeneous distribution is typically chosen so that at least one selected thin layer of the current limiting device has much higher resistance than the rest of the current limiting device. In the actual device, pressure is typically exerted on the composite material in a direction normal to the selected thin layer. During a short-circuit, it is believed that adiabatic resistive heating of this selected thin layer is followed by rapid thermal expansion which leads to either a partial or complete physical separation of the current limiting device at the selected thin layer which produces a higher over-all device resistance to electric current flow. Thus the current limiting device limits the flow of current through the short-circuited current path. When the short-circuit is cleared, the current limiting device regains its low resistance state allowing electrical current to flow normally. The current limiting of the present invention is reusable for many such short circuit conditions.
摘要:
A solid state seed crystal process for bulk conversion of a polycrystalline ceramic body to a single crystal body (of the same chemical composition) having the same crystal orientation as the seed crystal. The process comprises heating said body to form a monolithic join between the body and the seed crystal, heating the joined structure to reduce grain growth inhibitors and further heating the joined structure above the minimum temperature required for crystallite growth of the crystalline material, but not hot enough to melt and distort the original shape of the polycrystalline ceramic body during its conversion to a single crystal. This process has been used to convert polycrystalline alumina (PCA) bodies to sapphire having the same crystal orientation as the seed crystal by heating the PCA body, monolithically joined to a sapphire seed crystal, at a temperature above 1700.degree. C. without melting the body.