Abstract: Solar concentrators are arranged in an array to define an input aperture such that the solar collector is positionable to face the input aperture of the concentrators skyward. An input axis of rotation extends through the aperture in the skyward direction, and a focus region is smaller than the aperture. Each concentrator includes at least one optical arrangement that is supported for rotation about the input axis for tracking the sun within a predetermined range of positions of the sun using no more than the rotation of the optical arrangement around the input axis. An optical concentrator is described in which a receiving direction extends at an acute angle from an optical axis and in one azimuthal direction outward from the optical axis such that a component of the concentrator is rotatable about the optical axis for alignment to receive input light. A previously unknown inverted off-axis lens is described.

Abstract: Solar concentrators are arranged in an array to define an input aperture such that the solar collector is positionable to face the input aperture of the concentrators skyward. An input axis of rotation extends through the aperture in the skyward direction, and a focus region is smaller than the aperture. Each concentrator includes at least one optical arrangement that is supported for rotation about the input axis for tracking the sun within a predetermined range of positions of the sun using no more than the rotation of the optical arrangement around the input axis. An optical concentrator is described in which a receiving direction extends at an acute angle from an optical axis and in one azimuthal direction outward from the optical axis such that a component of the concentrator is rotatable about the optical axis for alignment to receive input light. A previously unknown inverted off-axis lens is described.

Abstract: A magnetic recording head includes a first pole having multiple magnetic layers separated by multiple gap layers. The multiple magnetic layers make up a write pole which produces a first hard axis field and a first auxiliary pole that produces a first auxiliary field that opposes the first hard axis field resulting in a reduced net hard axis field. The write pole and the first auxiliary pole are separated by a first gap layer made of a material that is less magnetically conducting than the write pole and the first auxiliary pole. The write pole is located upstream from the first auxiliary pole relative to a perpendicular magnetic recording medium. A portion of the first auxiliary pole exists in a region between a surface of the perpendicular magnetic recording medium and five microns from a surface of the perpendicular magnetic recording medium.

Abstract: A magnetic recording head includes a first pole having multiple magnetic layers separated by multiple gap layers. The multiple magnetic layers make up a write pole which produces a first hard axis field and a first auxiliary pole that produces a first auxiliary field that opposes the first hard axis field resulting in a reduced net hard axis field. The write pole and the first auxiliary pole are separated by a first gap layer made of a material that is less magnetically conducting than the write pole and the first auxiliary pole. The write pole is located upstream from the first auxiliary pole relative to a perpendicular magnetic recording medium. A portion of the first auxiliary pole exists in a region between a surface of the perpendicular magnetic recording medium and five microns from a surface of the perpendicular magnetic recording medium.

Abstract: A waveform generator embodied in a single tester unit. The hardware includes an integrated high frequency digital/analog signal generator that allows “infinite” length of signals, integrated colored noise source with thermal asperity generator and a PC style computer including standard storage systems and connectors that are custom configurable. Optionally, additional hardware such as an oscilloscope can be integrated to further centralize all the tools required by the engineer without adding interconnectivity problems for the engineer to deal with. The software includes a generic or standard operating system, GUI (graphical user interface), and specialized interface software for easy input/definition of sequences, waveform, and drive configuration. The software also includes a mathematical model of the head/disk system used in drives, with customization options, and the ability to do monte-carlo analysis to study distributions of signal waveforms.