Abstract: A (meth)acrylate-based block copolymer including a polymer block and a (meth)acrylate-based polymer block, wherein: the (meth)acrylate-based block copolymer contains 5 to 30% by mass of the polymeric block and 70 to 95% by mass of the (meth)acrylate-based polymer block with respect to 100% by mass of the (meth)acrylate-based block copolymer; the polymer block has a monomer unit derived from a monomer; when the monomer is polymerized alone, a polymer with a glass transition temperature of 80° C. or higher can be obtained; and a tensile strength at break measured in accordance with JIS K 6251 of a film obtained by immersion-molding a (meth)acrylate-based block copolymer latex containing the (meth)acrylate-based block copolymer and heat-treating at 130° C. for 30 minutes is 14 MPa or more.

Abstract: An example thin substrate built-in hard disk drive includes a magnetic disk in a disk shape having a through-hole at the center, a spindle motor inserted into the through-hole of the magnetic disk and co-rotatably supporting the magnetic disk, and a base plate made of an aluminum alloy and supporting the spindle motor. The base plate has a metallographic structure in which a perimeter of a second phase particle having a longest diameter of 10 ?m or more is 3 mm/mm2 or more, and the number of second phase particles having a longest diameter of 500 ?m or more is 0 particles/mm2.

Abstract: An aluminum alloy disc blank for a magnetic disc made of an aluminum alloy containing Mg: 3.40 to 3.90 mass % with the balance being A1 and inevitable impurities, wherein a conductivity of the aluminum alloy disc blank is 36.0% IACS or higher.

Abstract: An aluminum alloy substrate for a magnetic disc is made of an aluminum alloy, containing Fe: 1.80 mass % or less, Mn: 0.70 mass % or less, Ni: 2.50 mass % or less, Si: 2.50 mass % or less, Cu: 1.00 mass % or less, Zn: 0.48 mass % or less and Mg: 1.00 to 3.50 mass %, wherein a total content of Fe, Mn and Ni is 1.60 to 4.50 mass % and a mass ratio of Cu/Zn is 0.01 to 0.35 or 6.00 to 50.00, with a balance being Al and inevitable impurities.

Abstract: 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 ?m or less.

Abstract: There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % of Fe and the balance of Al and unavoidable impurities, in which second phase particles having a longest diameter of 0.5 ?m or more and less than 2.0 ?m are dispersed at a distribution density of 5000 particles/mm2 or more; a method for producing the same; and a magnetic disk using the aluminum alloy substrate for a magnetic disk.

Abstract: A magnetic disk substrate includes an aluminum alloy including one type or two or more types of Fe: 8.5 mass % or less, Mn: 2.5 mass % or less, Ni: 6.5 mass % or less, and Mg: 4.5 mass % or less, a balance being Al and unavoidable impurities, wherein, when f (Hz) is a resonance frequency, ? (g/cm3) is a density, and t (mm) is a plate thickness, (f×?/t) is 3800 or greater; and a magnetic disk using the magnetic disk substrate.

Abstract: An aluminum alloy substrate for magnetic disks, including an aluminum alloy containing: 1.0 to 6.5 mass % of Mg; and the balance consisting of Al and unavoidable impurities, in which the distribution of Si—K—O-based particles with a longest diameter of 1 ?m or more adhering to the surface from the surrounding environment is equal to or less than one particle/6,000 mm2; and in which the distribution of Ti—B-based particles with a longest diameter of 1 ?m or more present on the surface is equal to or less than one particle/6,000 mm2, and a magnetic disk using the aluminum alloy substrate for magnetic disks.

Abstract: An aluminum alloy substrate for magnetic disks, including an aluminum alloy containing Fe as an essential element; at least one of Mn or Ni as selective elements; and the balance including Al and unavoidable impurities, with the total amount of Fe, Mn, and Ni having a relationship of 0.10 to 7.00 mass %; in which the distribution of Si—K—O-based particles with a longest diameter of 1 ?m or more adhering to the surface from the surrounding environment is equal to or less than one particle/6,000 mm2, and in which the distribution of Ti—B-based particles with a longest diameter of 1 ?m or more present on the surface is equal to or less than one particle/6,000 mm2; and a magnetic disk using the aluminum alloy substrate.

Abstract: There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, “%”) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an Al—Fe-based intermetallic compound having a longest diameter of 2 ?m or more and less than 3 ?m is dispersed at a distribution density of 1000 particles/mm2 or more, and a Mg—Si-based intermetallic compound having a longest diameter of 1 ?m or more is dispersed at a distribution density of 1 particle/mm2 or less; a method for producing the same; and a magnetic disk in which an electroless Ni—P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

Abstract: An aluminum alloy substrate (1) for magnetic disk satisfies at least two of three inequalities of an inequality group [A] and satisfies all of four inequalities of an inequality group [B], or satisfies at least two of the three inequalities of the inequality group [A] and satisfies all of four inequalities of an inequality group [C], when a plate thickness of the disk at a position (b1) is defined as tb1, a plate thickness at a position (b2) is defined as tb2, a plate thickness at a position (b3) is defined as tb3, a plate thickness at a position (a1) is defined as ta1, a plate thickness at a position (a2) is defined as ta2, and a plate thickness at a position (a3) is defined as ta3.

Abstract: There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % of Fe and the balance of Al and unavoidable impurities, in which second phase particles having a longest diameter of 0.5 ?m or more and less than 2.0 ?m are dispersed at a distribution density of 5000 particles/mm2 or more; a method for producing the same; and a magnetic disk using the aluminum alloy substrate for a magnetic disk.

Abstract: An aluminum alloy substrate (1) for magnetic disk satisfies at least two of three inequalities of an inequality group [A] and satisfies all of four inequalities of an inequality group [B], or satisfies at least two of the three inequalities of the inequality group [A] and satisfies all of four inequalities of an inequality group [C], when a plate thickness of the disk at a position (b1) is defined as tb1, a plate thickness at a position (b2) is defined as tb2, a plate thickness at a position (b3) is defined as tb3, a plate thickness at a position (a1) is defined as ta1, a plate thickness at a position (a2) is defined as ta2, and a plate thickness at a position (a3) is defined as ta3.

Abstract: There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, “%”) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an Al—Fe-based intermetallic compound having a longest diameter of 2 ?m or more and less than 3 ?m is dispersed at a distribution density of 1000 particles/mm2 or more, and a Mg—Si-based intermetallic compound having a longest diameter of 1 ?m or more is dispersed at a distribution density of 1 particle/mm2 or less; a method for producing the same; and a magnetic disk in which an electroless Ni—P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

Abstract: An aluminum alloy substrate for a magnetic disk, wherein the sum of the circumferences of second phase particles having the longest diameter of 4 ?m or more and 30 ?m or less in the metal microstructure is 10 mm/mm2 or more.

Abstract: An aluminum alloy substrate for a magnetic disk includes 0.5 mass % or more and 24.0 mass % or less of Si, 0.01 mass % or more and 3.00 mass % or less of Fe, and the balance of Al and unavoidable impurities. The aluminum alloy substrate for a magnetic disk includes a smooth plated surface and has high rigidity.

Abstract: A communication system includes a plurality of port switches that include first and second port switches, a plurality of fabric switches that construct communication paths among the plurality of port switches, and a user switch. Each of the plurality of port switches is connected to each of the plurality of fabric switches via different communication lines. The first and second port switches are connected by a common communication line between redundancy ports of the first and second port switches to thereby form a same domain group. The user switch is connected to each of the first and second port switches via different communication lines, and also sets link aggregation for ports of the user switch that are connection sources of the communication lines that connect the user switch and each of the first and second port switches.

Abstract: In a multi-chassis link-aggregation device, each of first and second switch devices is provided with a relay condition, which defines prohibition of a predetermined relay path. If there is no link failure in each multi-chassis link-aggregation device, each of the first and second switch devices prohibits forwarding of a frame, which has been received by a bridge port, from each multi-chassis link-aggregation device. On the other hand, if a link failure is present in a second port (second multi-chassis link-aggregation device) of the first and second switch devices permits forwarding of the frame, which has been received by the bridge port, from the second port. In this case, if a destination port of the frame received by a first port includes the second multi-chassis link-aggregation device, the first switch device adds a port identifier representing the received port to the frame and forwards that toward the second switch device.

Abstract: An address table can be easily shared (synchronized) between two switching devices for which multi-chassis link aggregation is set. When a destination port of a frame received at a port P2 is a port P1, one of the two switching devices for which the multi-chassis link aggregation is set creates a bridging frame containing a transmission source address contained in the flame and an identifier of the port which has received, and transfers the bridging frame from a bridging port. When the other of the two switching devices receives the bridging frame, the other of the two switching devices detects the identifier of the port which has received and the transmission source address from the frame, and updates an address table of its own based on the identifier, the transmission source address, and a link table of its own.

Abstract: A metal member for magnetic storage medium includes an aluminum alloy substrate, and a nonmagnetic layer formed on at least one surface of the aluminum alloy substrate, and the nonmagnetic layer comprises a Ni—Cu—P based alloy containing 5 mass % to 50 mass % Cu and 100 ppm to 1000 ppm Pb.