Abstract: The present invention relates to a kind of biodegradable polyester and its preparation method, which belongs to the field of biodegradable co-polyester product technology. The number-average molecular weight of the biodegradable polyester material under this invention is 6000-135000 g/mol, the molecular weight distribution is 1.2-6.5, and the range of crystallization temperature is 15° C.-105° C., which could overcome the disadvantages of existing technical products and can be processed into membrane materials, sheet materials and foam materials. During processing, the picking property will be dramatically changed with the appearance quality improved; after heat resistance is improved, this new type of polyester material could also be applied to the processing course with long cycles, for example, the injection processing course, and the biodegradable aliphatic/aromatic polyester materials provided by this invention has excellent mechanical properties.

Abstract: A device may be provided. The device includes a media including a servo layer and a data recording layer, and a recording head including a dimension sized to produce a magnetic writing field to write servo information on the servo layer.

Abstract: A medium may be provided. The medium includes a servo layer, a data recording layer, and a heat sink layer disposed between the servo layer and the recording layer.

Abstract: In various embodiments, a recording medium having a servo layer configured to provide servo information and a data recording layer configured to record data, wherein the medium comprises a plurality of servo patterns and a plurality of data segment in one sector, each data segment corresponding to each of the plurality of servo patterns, wherein the plurality of servo patterns comprises a first servo pattern comprising an automatic gain control, a second servo pattern comprising a sector address mark, a third servo pattern comprising a GrayCode, and a fourth servo pattern comprising a plurality of servo bursts, wherein the data recording layer is configured to record the data on the data segments corresponding to the first, second, third and fourth servo patterns.

Abstract: Apparatuses and methods for certifying a magnetic recording disk (102) are disclosed herein, in a described embodiment, the apparatus (100) comprises a certifier head (104) for testing the disk's magnetic properties and a product head (106) for testing the disk's mechanical properties and the apparatus (100) is configured to enable simultaneous access to the disk (102) by the product head (106) and the certifier head (104). A method of upgrading a media certifier is also disclosed.

Abstract: A magnetic media tester comprising a Laser Doppler Vibrometer (LDV) head; and a magnetic read head; the LDV head and the magnetic read head being configured for obtaining correlatable data of a region on a magnetic disk.

Abstract: A system and method for trapping electron assisted magnetic recording is disclosed. A magnetic recording system comprises a magnetic storage media, a read/write head, and a power supply for applying a negative DC electrical bias to the magnetic storage media in order to reduce the media switching field during the writing process. Recording is performed by applying an AC magnetic field produced by a write pole and a DC electrical field to assist in the writing. An embodiment of the invention uses a high electrical field to trap free electrons into an unfilled electronic shell of magnetic particles of the magnetic storage media, in particular, (3d) shell of transition elements, (4f) shell of rare earths of lanthanides series, and (5f) shell of actinides series. The trapped electron decreases anisotropy of magnetic particles due to reduced number of Bohr magnetron. As a result, a conventional head is able to write very high anisotropy magnetic storage media.

Abstract: The present invention relates to a kind of biodegradable polyester and its preparation method, which belongs to the field of biodegradable co-polyester product technology. The number-average molecular weight of the biodegradable polyester material under this invention is 6000-135000 g/mol, the molecular weight distribution is 1.2-6.5, and the range of crystallization temperature is 15° C.-105° C., which could overcome the disadvantages of existing technical products and can be processed into membrane materials, sheet materials and foam materials. During processing, the picking property will be dramatically changed with the appearance quality improved; after heat resistance is improved, this new type of polyester material could also be applied to the processing course with long cycles, for example, the injection processing course, and the biodegradable aliphatic/aromatic polyester materials provided by this invention has excellent mechanical properties.

Abstract: A method for obtaining a refractive index (n) and extinction coefficient (k) map of a slider surface, the method comprising the steps of processing an image of the slider surface to obtain spatially resolved normalized intensity data of the slider surface; measuring n and k values of the slider surface at different areas of the slider surface to obtain reflectivity data of the slider surface; mapping a distribution of the normalized intensity data to a distribution of the reflectivity data for deriving the n and k map of the slider surface.

Abstract: A method for optical flying height measurement, and a flying height tester.

Abstract: In a recording device, a bit patterned medium comprises a track of bit cells, each settable to one of two distinct bit states. The track comprises two generally parallel rows of bit cells. The bit cells in one row are offset in a down track direction from the bit cells in the other row. A write head spans the two rows. A controller synchronously applies write signals to the write head to set the trailing bit cell covered by the write head as the track moves relative to the write head, and thereby write data to the track. The trailing bit cell covered by the write head alternates from being in one row to being in another row. Read sensors are positioned to independently read bit cells in respective rows, as the track moves relative to the write head along the down track direction.

Abstract: A method for optical flying height measurement, and a flying height tester.

Abstract: A method for obtaining a refractive index (n) and extinction coefficient (k) map of a slider surface, the method comprising the steps of processing an image of the slider surface to obtain spatially resolved normalized intensity data of the slider surface; measuring n and k values of the slider surface at different areas of the slider surface to obtain reflectivity data of the slider surface; mapping a distribution of the normalized intensity data to a distribution of the reflectivity data for deriving the n and k map of the slider surface.

Abstract: In a method based on readback signal for in-situ measuring of absolute head-medium spacing, a pre-encoded pattern in the magnetic medium on a disk has at least two harmonics with amplitudes such that a linear function of the logarithmic ratio of the spacing loss-term is formed in relation to testing frequencies. This linear function is applied to determine the absolute head-medium spacing directly through the multiplication of gradient of the linear function and the linear velocity between the head and the medium of the disk drive.

Abstract: In a method based on readback signal for in-situ measuring of absolute head-medium spacing, a pre-encoded pattern in the magnetic medium on a disk has at least two harmonics with amplitudes such that a linear function of the logarithmic ratio of the spacing loss-term is formed in relation to testing frequencies. This linear function is applied to determine the absolute head-medium spacing directly through the multiplication of gradient of the linear function and the linear velocity between the head and the medium of the disk drive.