Abstract: A resin composition and a resin film are provided. The resin composition includes a hardener and an epoxy resin monomer. The epoxy resin monomer has a structure represented by Formula (I) wherein A is substituted or unsubstituted C6-24 arylene group, C3-16 cycloalkylene group, C3-16 heteroarylene group, C3-16 alicyclic alkylene group, or divalent C6-25 alkylaryl group; X1 and X2 are independently Y1 and Y2 are independently substituted or unsubstituted C6-24 arylene group, and Y1 is different from Y2; and R1 is hydrogen, C1-8 alkyl group, or C1-8 alkoxy group, wherein the weight ratio of the curing agent to the epoxy resin monomer having a structure represented by Formula (I) is from 1:100 to 1:1.

Abstract: A certificate management system includes an electronic device and a server. The electronic device is configured to transmit a certificate application request. The server is configured to sign a device certificate corresponding to the electronic device through an intermediate certificate device after receiving the certificate application request, and transmit the device certificate and the Internet address of the server to the electronic device. The electronic device stores the device certificate and the Internet address of the server to complete the certificate issuance operation.

Abstract: A certificate transfer system includes a first certificate management host and a certificate transfer management host. The first certificate management host is configured to generate a first certificate, sign an electronic device with the first certificate, and transmit a first Internet address to the electronic device to complete a certificate-issuance operation. The certificate transfer management host is configured to store a transfer device list and a second Internet address. When the first certificate management host receives the first certificate issued by the electronic device, the first certificate management host verifies that the first certificate is correct and determines that if the first certificate matches one of the certificates in the transfer device list, the first certificate management host returns the certificate transfer management host address to the electronic device.

Abstract: A certificate management system includes an electronic device and a server. The electronic device is configured to transmit a certificate application request. The server is configured to sign a device certificate corresponding to the electronic device through an intermediate certificate device after receiving the certificate application request, and transmit the device certificate and the Internet address of the server to the electronic device. The electronic device stores the device certificate and the Internet address of the server to complete the certificate issuance operation.

Abstract: A certificate transfer system includes a first certificate management host and a certificate transfer management host. The first certificate management host is configured to generate a first certificate, sign an electronic device with the first certificate, and transmit a first Internet address to the electronic device to complete a certificate-issuance operation. The certificate transfer management host is configured to store a transfer device list and a second Internet address. When the first certificate management host receives the first certificate issued by the electronic device, the first certificate management host verifies that the first certificate is correct and determines that if the first certificate matches one of the certificates in the transfer device list, the first certificate management host returns the certificate transfer management host address to the electronic device.

Abstract: An adjustable bicycle stem structure comprising a horizontal tube and a longitudinal tube, one end of the longitudinal tube is provided with a rotatable shuttle-shaped threaded tube, and the corresponding end of the horizontal tube is provided with a push member. The external edge of the push member is provided with a row of toothed slots, which are distributed in the shape of a recessed arc. The toothed slots are made to mesh with the protruded threads of the threaded tube. When the shuttle-shaped threaded tube is rotating, it drives the push member to displace up and down following the threads on the threaded tube, allowing the horizontal tube to be adjusted up and down.

Abstract: A locking mechanism for the head tube of a bicycle in which the two ends of the head tube are respectively provided with a horizontal race and a vertical race. The horizontal race is provided for the handlebar to feed through, and the vertical race cooperates with a vertical tube for locking. The wall of the vertical race is provided with a feed-through lateral passage, which communicates with the vertical race through an intersecting hole. A stop member is placed inside the intersecting hole, and the two sides of the stop member are respectively provided with a push member. The side of the stop member facing the vertical race is provided with a recessed arc surface, and the opposite side is a V-shaped protruded portion, which is provided with a fixed ring. The two push members are respectively provided with a screw hole for a stove bolt to feed through so that the fixed ring can be locked together.

Abstract: A bicycle handlebar stem mounting device which includes a handlebar stem having a hollow tapered mount at one end mounted on the head tube of a bicycle and a clamping device at an opposite end to hold a handlebar, a tapered ring fixated into the tapered mount and mounted around the head tube, a top cap covered on the tapered mount fasten a handlebar stem, an actuating disk engaged inside the tapered mount, a hollow truncated rubber cone inserted in the head tube, a screw nut received inside the truncated rubber cone, and a screw bolt screw up with the screw nut to connect the top cap, the actuating disk, and the truncated rubber cone together, wherein turning the screw bolt inwards causes the truncated rubber cone to be deformed, and therefore the truncated rubber cone firmly stops against the inside wall of the head tube.