The Furukawa Electric Co., Ltd.

Uacj Corporation

Shinpei Todo

Yasuhiro Naka

Kotaro Kitawaki

Hideyuki Hatakeyama

Ryohei Yamada

Yoshimi Ono

Takayuki Ando

Takashi Shigematu

Akira Aikawa

Toshihiro Nakamura

Ryo Sakamoto

Masahide Kuwabara

Yukio Kohmura

Wataru Kumagai

Kiyoshi Arima

A magnetic disk device includes a plurality of disk-shaped magnetic disks, spacers, a hub, a clamp, and a fastening member. Each of the magnetic disksincludes a through-hole in a center section thereof. Each of the spacersincludes a through-hole in a center section thereof, and is disposed among the magnetic disks. The hubis inserted into the through-holes of the magnetic disksand the spacers. The clamppresses and holds the magnetic disksand the spacers. The fastening memberfastens the clampto the hub. The clampis fastened to the hub by the fastening memberwith a torque of from 5 cN·m to 45 cN·m.

Magnetic disk device and method for manufacturing magnetic disk device

A magnetic disk device includes a plurality of disk-shaped magnetic disks, a spacer, a hub, and a clamp. Each of the magnetic disks includes a through-hole in a center section thereof. The spacer is disposed among the magnetic disks, and includes a through-hole in a center section thereof. The hub is inserted into the through-holes of the magnetic disks and the spacers. The clamp presses and holds the magnetic disks and the spacer. At surfaces where the magnetic disks and the spacer or the clamp contact, a flat surface height of an upper surface of at least one magnetic disk that contacts an outer circumference of the spacer or the clamp is lower than a flat surface height of the upper surface of at least one magnetic disk of the magnetic disks that contacts an inner circumference of the spacer or the clamp.

Impact resistant magnetic disk device and method for manufacturing impact resistant magnetic disk device

An aluminum alloy disc blank for a magnetic disc made of an aluminum alloy containing Fe: 0.005 to 1.800 mass % with the balance being Al and inevitable impurities, wherein a flatness change of the aluminum alloy disc blank for a magnetic disc when the aluminum alloy disc blank for a magnetic disc is held in the atmosphere at 50° C. or lower for 336 hours is 2.0 μm or less.

Aluminum alloy disc blank for magnetic disc and magnetic disc

There is provided a glass substrate for a magnetic disk in which a maximum height of bumps forming a roughness pattern at a period of smaller than 2 &#x3bc;m is 6 nm or lower in an annular area having a width of 30 &#x3bc;m on a main surface on which a magnetic recording area is formed, a number of bumps having a height of 3 nm or higher in a unit area having a circular arc length of 30 &#x3bc;m within the annular area is one or less, and a difference in arithmetic average roughness between unit areas within the annular area is 0.2 nm or smaller.

Glass substrate for magnetic disk

A connecting member which is formed by filling a mold with a resin composition and then solidifying the resin composition, the connecting member having one end face in which a plurality of fine holes of a &#x3c6; or less are arrayed in a row with a pitch P therebetween, and guide pin insertion holes are formed on either side of the fine holes, wherein the resin composition is comprised of a resin and a filler mixed therein, and wherein the space (P&#x2212;a) between the fine holes meets the following formula; Dm&#x3c;(P&#x2212;a)&#x3c;Dmax, in which Dmax represents the largest diameter of the filler particles, and Dm represents the most frequent diameter of the filler particles.

Connecting member

An end heating and processing method of an optical fiber preform. In this method, an optical fiber preform is processed by heating and melting an end of a vitrified optical fiber preform including a core portion and a cladding portion formed on an outer circumference thereof to process the end having a shape for drawing as an optical fiber.

Method of heating and processing an end of an optical fiber preform and apparatus for heating and processing an end of an optical fiber preform

In a defect detecting method for detecting defect of a measured optical fiber, the defect of the optical fiber is detected on the basis of a pattern of the intensity distribution obtained by illuminating a laser beam on to the optical fiber, the pattern of the intensity distribution is subjected to a weak smoothing process and a strong smoothing process to form first and second pattern, respectively, and a judging pattern is formed on the basis of a difference or quotient between the first and second pattern, and then is subjected to Fourier transform to form a Fourier transform pattern which is evaluated by using double logarithmic axis, and judging curve having high contributing rate to the Fourier transform pattern is applied to the Fourier transform pattern, and the defect of the optical fiber is detected on the basis of magnitude of the dispersion of the Fourier transform pattern from the judging curve.

Method for detecting defect of optical fiber

In defect detecting method for detecting defect of an optical fiber to be measured, in which a laser beam is illuminated onto an optical fiber to be measured from a direction transverse to an optical axis of the fiber to check intensity distribution of forward scattering light permeated through within the optical fiber and scattered, and the defect of the optical fiber to be measured is detected on the basis of a pattern of the intensity distribution, the pattern of the intensity distribution is subjected to a smoothing process having weak smoothness and a smoothing process having strong smoothness to form first and second patterns, respectively, and a judging pattern is formed on the basis of a difference or the quotient between the first and second patterns, and the defect of the optical fiber to be measured is detected by evaluating magnitude of the judging pattern. The pattern of the intensity distribution is subjected to Fourier transform to form a frequency spectrum pattern, and the frequency spectrum pattern is evaluated by using double logarithmic axis, and a judging curve having high contributing rate to the frequency spectrum pattern is applied to the frequency spectrum pattern to seek dispersion of the frequency spectrum pattern from the judging curve, and the defect of the optical fiber to be measured is detected on the basis of magnitude of the dispersion.

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Tokyo, Japan

Shinpei Todo