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57 results about "Logarithmic decrement" patented technology

Logarithmic decrement, δ, is used to find the damping ratio of an underdamped system in the time domain. The method of logarithmic decrement becomes less and less precise as the damping ratio increases past about 0.5; it does not apply at all for a damping ratio greater than 1.0 because the system is overdamped.

Magnetic recording medium and magnetic recording and reproducing device

Provided are a magnetic recording medium, in which a magnetic layer includes ferromagnetic hexagonal ferrite powder, a binding agent, and an oxide abrasive, an intensity ratio Int(110) / Int(114) obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic recording medium is 0.65 to 1.00, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and a magnetic recording and reproducing device including this magnetic recording medium.
Owner:FUJIFILM CORP

Magnetic tape having controlled surface properties of the magnetic layer and method of manufacturing the same

The magnetic tape has a nonmagnetic layer containing nonmagnetic powder and binder on a nonmagnetic support, and has a magnetic layer containing ferromagnetic powder and binder on the nonmagnetic layer, wherein the combined thickness of the magnetic layer and the nonmagnetic layer is less than or equal to 0.80 μm; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050 and the coefficient of friction as measured on a base portion of the surface on the magnetic layer side is less than or equal to 0.35.
Owner:FUJIFILM CORP

Magnetic tape device and head tracking servo method

The magnetic tape device including: a magnetic tape; and a servo head, in which the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape device and head tracking servo method

The magnetic tape device includes a magnetic tape; and a servo head, in which the servo head is a TMR head, the magnetic tape includes a servo pattern in the magnetic layer, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and a ratio (Sdc / Sac) of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster thereof in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.
Owner:FUJIFILM CORP

Magnetic tape device and head tracking servo method

The magnetic tape device includes a TMR head as a servo head; and a magnetic tape which includes a magnetic layer including ferromagnetic hexagonal ferrite powder and a binding agent, and including a servo pattern, an XRD intensity ratio (Int(110) / Int(114)) of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape device and magnetic reproducing method

The magnetic tape device includes a TMR head as a reproducing head; and a magnetic tape which includes a non-magnetic support, and a magnetic layer including ferromagnetic hexagonal ferrite powder and a binding agent on the non-magnetic support, an XRD intensity ratio (Int(110) / Int(114)) of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape and method of manufacturing the same

The magnetic tape has a nonmagnetic layer containing nonmagnetic powder and binder on a nonmagnetic support, and has a magnetic layer containing ferromagnetic powder and binder on the nonmagnetic layer, wherein the combined thickness of the magnetic layer and the nonmagnetic layer is less than or equal to 0.80 μm; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050 and the coefficient of friction as measured on a base portion of the surface on the magnetic layer side is less than or equal to 0.35.
Owner:FUJIFILM CORP

Magnetic tape and magnetic tape device

The magnetic tape includes a non-magnetic support; a non-magnetic layer including non-magnetic powder and a binder on the non-magnetic support; and a magnetic layer including ferromagnetic powder and a binder on the non-magnetic layer, in which the total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 μm, the magnetic layer includes a timing-based servo pattern, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape device and head tracking servo method

The magnetic tape device including: a magnetic tape including a servo pattern on a magnetic layer; and a TMR head as a servo head, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is equal to or smaller than 0.50, wherein the SFD25° C. is SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.
Owner:FUJIFILM CORP

Magnetic tape and method of manufacturing the same

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the centerline average surface roughness Ra as measured on the surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm, and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050.
Owner:FUJIFILM CORP

Magnetic tape device and magnetic reproducing method

The magnetic tape device includes a magnetic tape; and a TMR head as a reproducing head, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is equal to or smaller than 0.50, wherein, in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.
Owner:FUJIFILM CORP

Magnetic tape

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is equal to or greater than 0.35. In Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.
Owner:FUJIFILM CORP

Magnetic tape device and magnetic reproducting method

The magnetic tape device includes a magnetic tape; and a reproducing head, in which the reproducing head is a TMR head, a center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and a ratio (Sdc / Sac) of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.
Owner:FUJIFILM CORP

Magnetic tape

The magnetic tape includes a non-magnetic support; a non-magnetic layer including non-magnetic powder and a binding agent on the non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic layer, in which the total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 μm, the magnetic layer includes an abrasive, a percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μm×6.3 μm of the surface of the magnetic layer with respect to the total area of the region, obtained by plane observation performed by using a scanning electron microscope is equal to or greater than 0.02% and less than 0.06%, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape having controlled surface properties of the backcoat layer and method of manufacturing the same

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on the surface on one side of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the surface on the other side of the nonmagnetic support, wherein the backcoat layer is less than or equal to 0.30 μm in thickness; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the backcoat layer side of the magnetic tape is less than or equal to 0.060.
Owner:FUJIFILM CORP

Magnetic tape

The magnetic tape includes a back coating layer having a thickness equal to or smaller than 0.30 μm and including fatty acid ester, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the back coating layer is equal to or smaller than 0.060, a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before and after performing a vacuum heating with respect to the magnetic tape is respectively greater than 0 nm and equal to or smaller than 10.0 nm, and a difference between a spacing measured by optical interferometry regarding the surface of the back coating layer after performing the vacuum heating and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.
Owner:FUJIFILM CORP

Magnetic tape

The magnetic tape includes a non-magnetic support; a magnetic layer including ferromagnetic powder and a binding agent on one surface side of the non-magnetic support; and a back coating layer including non-magnetic powder and a binding agent on the other surface side of the non-magnetic support, in which a thickness of the back coating layer is equal to or smaller than 0.30 μm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the back coating layer is equal to or smaller than 0.060, and a contact angle with respect to 1-bromonaphthalene measured regarding a surface of the back coating layer is 15.0° to 30.0°.
Owner:FUJIFILM CORP

Magnetic tape and magnetic recording and reproducing device

Provided are a magnetic tape, in which a magnetic layer includes a ferromagnetic powder, a binding agent, and an oxide abrasive, ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1, ΔSFD=SFD25° C.−SFD−190° C., is equal to or smaller than 0.50, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, and an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and a magnetic recording and reproducing device including this magnetic tape.
Owner:FUJIFILM CORP

Magnetic tape

The magnetic tape includes a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent and a back coating layer including non-magnetic powder and a binding agent, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, an Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the hack coating layer is equal to or smaller than 0.060.
Owner:FUJIFILM CORP

Magnetic tape and magnetic recording and reproducing device

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape having characterized magnetic layer

A magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support. The center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 1.8 nm. The logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is greater than or equal to 0.35. In Expression 1, the SFD25° C. is the switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is the switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.
Owner:FUJIFILM CORP

Magnetic tape device and reproducing method employing TMR reproducing head and magnetic tape with characterized magnetic layer

A magnetic tape device includes a magnetic tape; and a Tunneling Magnetoresistive (PAR) head as a reproducing head, in which the center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is equal to or smaller than 0.50, wherein, in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.
Owner:FUJIFILM CORP

Magnetic tape device with TMR head and specific logarithmic decrement and magnetic reproducing method

The magnetic tape device includes: a magnetic tape; and a reproducing head, in which the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
Owner:FUJIFILM CORP

Magnetic tape having characterized magnetic layer

A magnetic tape includes a non-magnetic support; a non-magnetic layer including non-magnetic powder and a binding agent on the non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic layer. The total thickness of the non-magnetic layer and the magnetic layer is less than or equal to 0.60 μm. The magnetic layer includes an abrasive, and the percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μm×6.3 μm of the surface of the magnetic layer with respect to the total area of the region, obtained by plane observation performed by using a scanning electron microscope, is greater than or equal to 0.02% and less than 0.06%. Also, the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050.
Owner:FUJIFILM CORP

Support device for resonator

ActiveUS20110036897A1Large logarithmic decrementFaster sound propagation speedSolid-state devicesWelding/cutting auxillary devicesClassical mechanicsUltrasonic vibration
The purpose of this invention is to provide a support device for a resonator that can support the resonator at an optional location, can let the resonator vibrate with a specified vibration consistently, and can apply an ultrasonic vibration to objects efficiently. By inserting first clamping means and second clamping means, which comprise supporting member at least at each contacting portion, into first portion-to-be-supported and second portion-to-be-supported of resonator, the resonator is supported. As substances of the supporting member, substances that have a logarithmic decrement higher than 0.01 and lower than 1.0 and / or a sound propagation speed of more than 5900 m / s are suitable.
Owner:ADWELDS CORP
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