摘要:
The invention provides techniques for adjusting for actuator non-linearities in a data storage system. The invention is particularly useful for piezoelectric actuators, such as actuators that implement a bimorph piezoelectric crystal structure or a laminate piezoelectric crystal structure, although other actuators may present similar non-linearity issues. In one embodiment, the invention provides a method comprising applying a signal to an actuator of a data storage system, the actuator having a non-linear response, wherein the signal includes a linear drive component and a non-linear adjustment component, and positioning a data storage head with respect to a data storage medium via the actuator.
摘要:
The invention provides a read-while-write recording system for a linear data storage medium, such as magnetic tape or other data storage medium in which data is stored on parallel data tracks that extend along a length of the medium. The invention makes use of separate sliders for the read and write elements, and separate actuators to control the positioning of the sliders. Each of the sliders may also include servo elements to read servo marks. In this manner, the write elements of a first slider can be positioned independently from the read elements of a second slider in order to achieve improved head positioning with respect to data tracks on the linear data storage medium.
摘要:
A machining system having a machining envelope, a housing, a hopper, and a seal. The housing defines at least a portion of the machining envelope. The hopper has a top surface defining an opening. The seal is disposed between the housing and the top surface. The hopper is configured to receive particulates when positioned below the machining envelope.
摘要:
An apparatus and method for electrochemically modifying the retention of a species on a chromatography material is disclosed. The apparatus comprises a housing having an effluent flow channel adapted to permit fluid flow therethrough. The effluent flow channel comprises chromatography material. The apparatus further comprises first and second electrodes positioned such that at least a portion of the chromatography material is disposed between the first and second electrodes, and fluid flow through the apparatus is between, and in contact with, the first and second electrodes.
摘要:
Disclosed is an optical fiber having a core with an alkali metal oxide dopant in an peak amount greater than about 0.002 wt. % and less than about 0.1 wt. %. The alkali metal oxide concentration varies with a radius of the optical fiber. By appropriately selecting the concentration of alkali metal oxide dopant in the core and the cladding, a low loss optical fiber may be obtained. Also disclosed are several methods of making the optical fiber including the steps of forming an alkali metal oxide-doped rod, and adding additional glass to form a draw perform. Preferably, the draw preform has a final outer dimension (d2), wherein an outer dimension (d1) of the rod is less than or equal to 0.06 times the final outer dimension (d2). In a preferred embodiment, the alkali metal oxide-doped rod is inserted into the centerline hole of a preform to form an assembly.
摘要:
A process and apparatus for planting aquatic plants underwater on the bottom of estuaries in propeller scars and for encouraging plant growth in propeller scars. Aquatic plant shoots are transplanted by positioning shoots in a sediment tube which is in turn placed in the propeller scar. When the sediment tube is placed in the propeller scar the sea grass shoots are held in position for an extended period of time to allow the sea grass shoots to take root on the estuary bottom. The sediment tubes may be preformed or they may be formed just prior to their placement in the estuary. A watercraft may be used to position the sediment tubes with and without sea grass shoots over an area of the propeller scar. With the process and apparatus of this invention, sea grass plants can be replanted on the bottom of an estuary and new plant growth encouraged in propeller scars. Further in accordance with another embodiment of this invention a tube or other obstruction without plant shoots is placed in a propeller scar in order to impede water flow through the propeller scar. When water flow through the propeller scar is impeded natural plant growth is encouraged.
摘要:
A process for synthesizing L and D-5,5,5,5′,5′,5′-hexafluoroleucine and protected analogs is disclosed. These compounds have utility in the preparation of fluorous peptides and proteins, which display interesting and unusual properties including strong self-association and an affinity for lipid bilayers.
摘要:
A tire comprising a tread at least one radialIy outermost reinforcing layer of belt reinforcing textile cords arranged substantially at a zero angle with respect to the mid circumferential center plane perpendicular to the axis of the tire, a carcass a tread compound which is in direct contact with the radially outward side of the cords.
摘要:
A one pot process is provided in which a Mannich base of the formula 5 is reacted with acetic anhydride to produce a diacetate derivative. Without any intermediate isolation, the derivative is hydrogenated to produce a reaction mixture containing 1-acetoxy-2-methylnaphthalene which is readily precipitated from the reaction mixture by addition of water. ##STR1##
摘要:
The invention provides accessories for use with a rotary lawn mower in which the conventional bar having oppositely facing cutting edges is replaced with an accessory bar to which a variety of grass grooming accessories can be easily attached. The accessory bar can accommodate replaceable grass cutting elements, grass mulching elements and lawn power raking elements. The elements can be replaced without removing the accessory bar from the mower and are balanced to reduce vibration. Two of the accessories have cutting edges which are factory sharpened on relatively low cost elements, and thus can be discarded when blunt and replaced with new, low cost factory sharpened elements, thus maintaining balance. The rake accessory has a variation which permits a fine adjustment of vertical height of the rake above the lawn, to accommodate lawn mowers having coarse or no height adjustment.