Abstract: Provided is a viscous-fluid-enclosing damper which attenuates, by using viscous resistance of a vibration-damping composition, vibrations transmitted between a support and an object to be supported, the support and object being attached to a closed container enclosing the vibration-damping composition of a viscous fluid. The viscous-fluid-enclosing damper alters few vibration-damping properties even when used under high temperatures and/or conditions where the vibrations are repeatedly generated for a prolonged period. Also provided is the vibration-damping composition which is used for the viscous-fluid-enclosing damper. The viscous fluid contains a viscous liquid having dispersed therein at least one type of heat-resistant resin particles and a dripping inhibitor, the particles being selected from polyethylene and nylon having an average molecular weight of from 50×104 to 600×104 and an average particle size of from 10 ?m to 200 ?m and preferably from 10 ?m to 160 ?m.

Abstract: Provided is a viscous fluid-sealed damper which helps to achieve an increase in degree of freedom in terms of the selection of the material of a sealing container, which can be produced with high production efficiency, and which helps to avoid leakage of the viscous fluid. A lid member is fixed to a container main body while compressing and holding a flange portion between a sealing member and the lid member, so an opening end of the container main body can be sealed with the lid member without having to effect fixation through fusion-bonding as in the prior art, and the degree of freedom in terms of material selection can be increased. Further, if the container main body is formed of a butyl rubber, the container main body can be fixed to the lid member without using any adhesive, so it is possible to achieve a reduction in production time and in cost. Further, it is possible to avoid leakage of the viscous fluid due to defective adhesion.

Abstract: Provided is a container body including a flexible portion made of a rubber-like elastic material and an annular connection portion made of a hard material in the shape of a substantially flat plate and having an upper surface to which the flexible portion is firmly fixed and a lower surface to which the lid body is firmly fixed. The flexible portion is provided, on a firm fixation region thereof that is firmly fixed to the annular connection portion, with a collar joint portion protruding widely in the direction of a plane of the annular connection portion. Therefore, the container body and the lid body are firmly coupled to each other, and the viscous fluid-filled damper can be reduced in height.

Abstract: Obtained is a viscous fluid-filled damper which makes it easy to determine whether or not a shaft or the like protruding from a supporting body side or a supported body side has been sufficiently inserted therein and which can be easily mounted on a supporting body or a supported body, and a mounting structure thereof. In the viscous fluid-filled damper, a shaft mounting portion of the viscous fluid-filled damper for damping vibrations between the supporting body and the supported body is provided with a shaft receiving hole for receiving the shaft, and a window hole intersecting the shaft receiving hole and having a hole port opening to a lateral surface of the shaft mounting portion. Therefore, it is easy to determine whether or not the shaft has been inserted correctly, and a large force for retaining the shaft is ensured.

Abstract: Provided is a viscous fluid-sealed damper which helps to achieve an increase in degree of freedom in terms of the selection of the material of a sealing container, which can be produced with high production efficiency, and which helps to avoid leakage of the viscous fluid. A lid member is fixed to a container main body while compressing and holding a flange portion between a sealing member and the lid member, so an opening end of the container main body can be sealed with the lid member without having to effect fixation through fusion-bonding as in the prior art, and the degree of freedom in terms of material selection can be increased. Further, if the container main body is formed of a butyl rubber, the container main body can be fixed to the lid member without using any adhesive, so it is possible to achieve a reduction in production time and in cost. Further, it is possible to avoid leakage of the viscous fluid due to defective adhesion.

Abstract: Disclosed is a viscous fluid-sealed damper including a sealing container with a flexible membrane portion, and a viscous fluid sealed in the sealing container, and adapted to attenuate vibration transmitted between a supporting member and a supported member, the damper involving no deterioration in vibration preventing performance even if placed in an unfavorable position during transportation or storage after assembly to a disk device. A flexible membrane portion is formed of a rubber-like elastic composition containing a styrene-isobutylene-based block copolymer, and, more preferably, a mixture composition including a styrene-isobutylene-based block copolymer containing a styrene-based block and an isobutylene-based block, and a styrene-non-isobutylene-based block copolymer containing a styrene-based block and a non-isobutylene-based block.

Abstract: Provided is a container body including a flexible portion made of a rubber-like elastic material and an annular connection portion made of a hard material in the shape of a substantially flat plate and having an upper surface to which the flexible portion is firmly fixed and a lower surface to which the lid body is firmly fixed. The flexible portion is provided, on a firm fixation region thereof that is firmly fixed to the annular connection portion, with a collar joint portion protruding widely in the direction of a plane of the annular connection portion. Therefore, the container body and the lid body are firmly coupled to each other, and the viscous fluid-filled damper can be reduced in height.

Abstract: Obtained is a viscous fluid-filled damper which makes it easy to determine whether or not a shaft or the like protruding from a supporting body side or a supported body side has been sufficiently inserted therein and which can be easily mounted on a supporting body or a supported body, and a mounting structure thereof. In the viscous fluid-filled damper, a shaft mounting portion of the viscous fluid-filled damper for damping vibrations between the supporting body and the supported body is provided with a shaft receiving hole for receiving the shaft, and a window hole intersecting the shaft receiving hole and having a hole port opening to a lateral surface of the shaft mounting portion. Therefore, it is easy to determine whether or not the shaft has been inserted correctly, and a large force for retaining the shaft is ensured.

Abstract: The instant invention is drawn to a method for manufacturing 2',3'-dideoxy-2',3'-didehydronucleoside compounds by reacting a ribonucleoside derivative wherein the hydroxyl in the 5'-position of the furanose ring of said ribonucleoside is protected by a silyl protective group, with an acid anhydride such as acetic anhydride in the presence of a catalyst such as hydrous zirconium oxide, and then subjecting the reaction product to decarboxylation. The decarboxylation can be effected by heating the reaction product. This method can be performed in a single step, and requires no reagents which are expensive or chemicals which should be handled with care. Hence, it serves to manufacture 2',3'-dideoxy-2',3'-didehydronucleosides easily at low cost.

Abstract: This invention provides a process for producing 3'-deoxy-'-fluorothymidine, which comprises allowing 3'-deoxy-'-fluoro-5'-mesylthymidine (the stating material) to react with an acetylating agent, selected from the group consisting of alkali metal salts of acetic acid, amine salts of acetic acid and ammonium acetate, in an aprotic, ploar solvent to form the 5'-acetyl derivative, and ammonium acetate, in an aprotic, polar solvent to form the 5'-acetyl derivative, and eliminating the 5'-acetyl group from this intermediate, thereby giving the objective 3'-deoxy-'-fluorothymidine.According to the process of this invention described above, the 5'-mesyl derivative can be efficiently acetylated, and 3'-deoxy-'-fluorotymidine can be obtained in a high yield.