Abstract: A damper includes a cavity and a rotation shaft. The rotation shaft is inserted into the cavity of the body in sealing way. An oil cavity is disposed between the cavity and the rotation shaft. The external wall of the rotation shaft is disposed with a pair of protruding ribs axially. Each protruding rib is a groove. One side of the groove is a first retaining wall and the other side is a second retaining wall. A transitional arc is disposed between the side wall of the groove and the top surface of the first retaining wall. A first shape is formed between the other side wall of the groove and the top surface of the second retaining wall. A blade is disposed between the groove of one protruding rib and an internal wall of the cavity, and the blade is movable between the two retaining walls of the groove.

Abstract: A method for measuring a change in a spacing between a head and a storage medium of a data storage system. The method includes obtaining a first readback signal from the storage medium using the head at a first spacing between the head and the storage medium, determining a first power spectrum density over a frequency range from the obtained first readback signal, obtaining a second readback signal from the storage medium using the head at a second spacing between the head and the storage medium, determining a second power spectrum density over the frequency range from the obtained second readback signal, and providing a measurement indicative of the change in the spacing based on the determined first power spectrum density and the determined second power spectrum density. A data storage system is also provided.

Abstract: A damper includes a cavity and a rotation shaft. The rotation shaft is inserted into the cavity of the body in sealing way. An oil cavity is disposed between the cavity and the rotation shaft. The external wall of the rotation shaft is disposed with a pair of protruding ribs axially. Each protruding rib is a groove. One side of the groove is a first retaining wall and the other side is a second retaining wall. A transitional arc is disposed between the side wall of the groove and the top surface of the first retaining wall. A first shape is formed between the other side wall of the groove and the top surface of the second retaining wall. A blade is disposed between the groove of one protruding rib and an internal wall of the cavity, and the blade is movable between the two retaining walls of the groove.

Abstract: A compound of the formula: (I) is provided, where R is selected from CF3, F, and H, and m is an integer from 1 to 22. The compound may be prepared by reacting a first reactant with a second reactant in a solution, where the first reactant is a 2,4-dichloro-2,4,6,6-tetra(aryloxy)-1,3,5-triaza-2,4,6-triphosphorine, and the second reactant is a perfluoropolyether of the formula CF3CF2CF2O(CF2CF2CF2O)mCF2CF2CH2OH. The aryloxy is selected from 4-(trifluoromethyl)phenoxy (p-CF3—C6H4O), 4-fluorophenoxy (p-F—C6H4O), and phenoxy (C6H5O). The first reactant may be prepared by reacting 2,2,4,4,6,6-hexachloro-1,3,5-triaza-2,4,6-triphosphorine with a phenoxide. The compound may be used in a lubricant for lubricating a surface. The lubricant may be applied to a recording surface in a magnetic recording device including a recording medium.

Abstract: A method and apparatus of detecting variations in a clearance distance between a magnetic read/write transducer and a magnetic recording disk having a clearance detection burst recorded thereon. The clearance detection burst has at least two groups of bit patterns each having different transition densities. The method may have the steps of obtaining a readback signal from the at least two groups of bit patterns, the readback signal being sensitive to variations in the clearance; detecting the amplitude of the readback signal of a first group. The amplitudes of the readback signals are detected and then compared to provide an indication of a variation in the clearance.