Abstract: According to one embodiment, a fuel cell includes a membrane electrode assembly including a plurality of unit cells which are composed of an electrolyte membrane, an anode including anode catalyst layers arranged at intervals on one of surfaces of the electrolyte membrane, and anode gas diffusion layers stacked on the anode catalyst layers, and a cathode including cathode catalyst layers arranged at intervals on the other surface of the electrolyte membrane and opposed to the anode catalyst layers, respectively, and cathode gas diffusion layers stacked on the cathode catalyst layers, wherein a thickness of at least one of the anode catalyst layer and the cathode catalyst layer of one of the unit cells, which neighbor each other, gradually decreases toward the other of the unit cells.

Abstract: According to one embodiment, a fuel cell includes a membrane electrode assembly including a plurality of unit cells which are composed of an electrolyte membrane, an anode including anode catalyst layers arranged at intervals on one of surfaces of the electrolyte membrane, and anode gas diffusion layers stacked on the anode catalyst layers, and a cathode including cathode catalyst layers arranged at intervals on the other surface of the electrolyte membrane and opposed to the anode catalyst layers, respectively, and cathode gas diffusion layers stacked on the cathode catalyst layers, wherein a thickness of at least one of the anode catalyst layer and the cathode catalyst layer of one of the unit cells, which neighbor each other, gradually decreases toward the other of the unit cells.

Abstract: To provide an information providing system which can easily and quickly provide various information about procurement.

Abstract: There is provided a magnetic recording/reproducing apparatus which has an improved reliability for a reproduced signal by eliminating a deformation in a reproduced signal waveform due to a residual magnetization generated in a magnetic head. The magnetic recording/reproducing apparatus has a magnetic recording medium including a magnetic film to which information is magnetically recorded and a thin-film magnetic head including a magnetic pole and a coil provided around the magnetic pole. A current supplying circuit supplies a current to the coil so that a magnetic state of the magnetic pole is stabilized. The current is supplied to the coil after a recording operation has been completed by the thin-film magnetic head. The current may demagnetize the magnetic pole of the magnetic head, or stabilize the magnetic state of the magnetic pole.

Abstract: A disk unit includes a mechanism which rotates a disk, a head which writes data to and/or reads data from the disk, a detection mechanism which detects an operating environment of the disk unit and outputs a detection signal, and a control unit which controls a floating distance of the head from the disk to more than a predetermined value by controlling the rotation mechanism and varying a rotational speed of the disk from a rated rotational speed if the detection signal falls outside a first range.

Abstract: There is provided a magnetic recording/reproducing apparatus which has an improved reliability for a reproduced signal by eliminating a deformation in a reproduced signal waveform due to a residual magnetization generated in a magnetic head. The magnetic recording/reproducing apparatus has a magnetic recording medium including a magnetic film to which information is magnetically recorded and a thin-film magnetic head including a magnetic pole and a coil provided around the magnetic pole. A current supplying circuit supplies a current to the coil so that a magnetic state of the magnetic pole is stabilized. The current is supplied to the coil after a recording operation has been completed by the thin-film magnetic head. The current may demagnetize the magnetic pole of the magnetic head, or stabilize the magnetic state of the magnetic pole.

Abstract: A magnetic recording medium able to cope with low flying height of the magnetic head in a CSS system and having fine surface roughness, wherein (1) a metal layer having columnar protrusions formed by the filming of Ti or the like or (2) a resin layer or glass resin layer having irregularly distributed through-holes are provided on the substrate of a magnetic recording medium to impart roughness (texture).

Abstract: A method of obtaining a limit glide height in flying a head above a recording medium being rotated. The first step is storing the medium and the head into a chamber, stepwise reducing an air pressure in the chamber, and measuring a flying height of the head and a frequency of contact of the head with the medium in each step. The second step is performing head vanish to polish away projections on the medium by means of the head under such conditions that the head at least intermittently comes into contact with the medium. The third step is reproducing the air pressure in each step in the first step, and again measuring a flying height of the head and a frequency of contact of the head with the medium in each step.

Abstract: A magnetic head for vertical magnetic recording includes a return portion having a sufficiently large area confronting a magnetic recording medium, a main pole having its front end portion confronting the magnetic recording medium, a magneto-resistive film provided in the middle of a magnetic circuit, including the return portion, the main pole, and the magnetic recording medium. The magnetic head has its initial magnetization set in the direction virtually orthogonal to the direction of flux in the magnetic circuit. A first and a second terminal are connected to both ends of the magneto-resistive film. The magnetic circuit also includes a bypass magnetic path magnetically connecting the main pole with the return portion.

Abstract: A perpendicular magnetic recording medium for use on a magnetic recording/reproducing apparatus which has a magnetic head for recording/reproduction includes a substrate, a magnetic recording layer having a perpendicular magnetic anisotropy, and a soft magnetic under layer interposed between the substrate and the magnetic recording layer. The soft magnetic under layer includes a mechanism for for suppressing motion of the domain walls of the soft magnetic under layer at least with respect to an external magnetic field which is smaller than a stray magnetic field in a vicinity of the magnetic head within the magnetic recording/reproducing apparatus.

Abstract: A magnetic recording medium, comprising Cr base layer containing up to about 25 atom % of nitrogen, preferably 5 to 15 atom %, and a magnetic film of Co alloy such as Co-Ni or Co-Ni-Cr alloy material deposited thereon, shows a clear improvement over that using a pure Cr base layer without nitrogen content in medium noise level and S/N ratio. In case of about 10 atom % nitrogen content in the base layer, the medium noise level is reduced by half and the S/N ratio is improved by 6 to 9 dB, while the other magnetic characteristics such as coercivity Hc, residual magnetization Br, and squareness ratio Sq are remaining the same.