Abstract: A polyimide precursor, a preparation method thereof, a photosensitive resin composition and a cured product are provided. The polyimide precursor is obtained from a tetracarboxylic dianhydride (A), a diamine (B), and a hydroxyl-containing alkyl (meth)acrylate (C) through ring-opening substitution, and polymerization. The polyimide precursor does not include fluorine. The tetracarboxylic dianhydride (A) and the diamine (B) form a main chain. The hydroxyl-containing alkyl (meth)acrylate (C) is grafted to the main chain to form a branch. A molar ratio of the tetracarboxylic dianhydride (A) to the diamine (B) if from 1:0.95 to 1:1.10.

Abstract: The present invention discloses a compact server power supply having high power density has a casing, a main printed circuit board, a sub-printed circuit board, a power supplying circuit, a power output terminal set and a fan. The power supplying circuit has a primary side circuit unit, a transformer and a secondary side circuit unit. Electric elements of the primary and secondary side circuit units and the transformer are soldered on the main printed circuit board except parts of the electric elements of the secondary side circuit unit are soldered on the sub-printed circuit board. The sub-printed circuit board is vertically mounted and soldered on the main printed circuit board, so the length of the main printed circuit board is shortened to implement the server power supply having a compact size and high power density.

Abstract: The present invention discloses a compact server power supply having high power density has a casing, a main printed circuit board, a sub-printed circuit board, a power supplying circuit, a power output terminal set and a fan. The power supplying circuit has a primary side circuit unit, a transformer and a secondary side circuit unit. Electric elements of the primary and secondary side circuit units and the transformer are soldered on the main printed circuit board except parts of the electric elements of the secondary side circuit unit are soldered on the sub-printed circuit board. The sub-printed circuit board is vertically mounted and soldered on the main printed circuit board, so the length of the main printed circuit board is shortened to implement the server power supply having a compact size and high power density.

Abstract: A coil of a transformer has two side conducting brackets and at least one middle conducting bracket. The middle conducting bracket is elongated or spiral-shaped and has two terminals respectively connected to the side conducting brackets. The side conducting brackets and the at least one middle conducting bracket of some specific type are connected to form different numbers of loops or different types of circuits (series circuits or parallel circuits). Therefore, design and fabrication of the coil is flexible and materials and manufacturing costs are saved. Moreover, the side conducting brackets and the at least one middle conducting bracket require only two or four soldered joints so number of soldered joints required is limited and efficiency of the transformer is improved.

Abstract: An electromagnetic component has a multilayer winding. The multilayer winding has a stack body. The stack body has multiple sub-stacks and at least one second metal ring, each of which is interposed between two adjacent sub-stacks of the stack body. Each sub-stack has identical upper and lower first metal rings. Further, each second metal ring has identical upper and lower half rings. Therefore, the multilayer winding only uses two forms of the metal rings, so manufacturing costs will be decreased.

Abstract: A power supply has an outer shell and a retention bar. The outer shell has a rear panel and a cover. The rear panel has a socket and two guide slots. The cover has two pivot slots and two pivot mounts. Each pivot slot is formed through the cover adjacent to a corresponding guide slot. The pivot mounts are formed from and protrudes inwardly from the cover and have pivot holes formed therethrough. The retention bar is mounted in the pivot holes of the pivot mounts and has a clip and two protrusions. Therefore, when the power supply is mounted in a casing of a machine, the retention bar simultaneously fastens the power supply to the casing and a plug to the power supply.

Abstract: An electromagnetic component has a multilayer winding. The multilayer winding has a stack body. The stack body has multiple sub-stacks and at least one second metal ring, each of which is interposed between two adjacent sub-stacks of the stack body. Each sub-stack has identical upper and lower first metal rings. Further, each second metal ring has identical upper and lower half rings. Therefore, the multilayer winding only uses two forms of the metal rings, so manufacturing costs will be decreased.

Abstract: A power supply has an outer shell and a retention bar. The outer shell has a rear panel and a cover. The rear panel has a socket and two guide slots. The cover has two pivot slots and two pivot mounts. Each pivot slot is formed through the cover adjacent to a corresponding guide slot. The pivot mounts are formed from and protrudes inwardly from the cover and have pivot holes formed therethrough. The retention bar is mounted in the pivot holes of the pivot mounts and has a clip and two protrusions. Therefore, when the power supply is mounted in a casing of a machine, the retention bar simultaneously fastens the power supply to the casing and a plug to the power supply.

Abstract: An power switching device includes a base with input wires and output wires electrically connected to the base and opposite to the input wires, multiple conducting tubes electrically connected to and orthogonally mounted on the base, and multiple conducting plates each having holes to selectively allow an extension of some of the conducting tubes and screw holes selectively defined to correspond to and allow a bottom face of each of the screw holes to abut free ends of the rest of the conducting tubes such that screws are able to threadingly extend from the screw holes and into the free ends of the conducting tubes abutted to the bottom faces of the screw holes to secure engagement between conducting plate and the conducting tubes.

Abstract: An electrical switching device includes a base with input wires and output wires electrically connected to the base and opposite to the input wires, multiple conducting tubes electrically connected to and orthogonally mounted on the base, and multiple conducting plates each having holes to selectively allow an extension of some of the conducting tubes and screw holes selectively defined to correspond to and allow a bottom face of each of the screw holes to abut free ends of the rest of the conducting tubes such that screws are able to threadingly extend from the screw holes and into the free ends of the conducting tubes abutted to the bottom faces of the screw holes to secure engagement between conducting plate and the conducting tubes.

Abstract: An power switching device includes a base with input wires and output wires electrically connected to the base and opposite to the input wires, multiple conducting tubes electrically connected to and orthogonally mounted on the base, and multiple conducting plates each having holes to selectively allow an extension of some of the conducting tubes and screw holes selectively defined to correspond to and allow a bottom face of each of the screw holes to abut free ends of the rest of the conducting tubes such that screws are able to threadingly extend from the screw holes and into the free ends of the conducting tubes abutted to the bottom faces of the screw holes to secure engagement between conducting plate and the conducting tubes.

Abstract: An improved photoreceptor is disclosed which contains a multi-layered charge generation layer formed on a substrate and a charge transport layer formed on the multi-layered charge generation layer. The multi-layered charge generation member is formed by sequentially forming a plurality of charge generation sub-layers first on the substrate then on the charge generation sub-layer that was already formed, so as to create at least one interface between the charge generation layers. The charge generation materials in the plurality of charge generation layers must satisfy the following relationship:(IP).sub.CGL1 .gtoreq.(IP).sub.CGL2 .gtoreq.(IP).sub.CGL3 . . . .gtoreq.(IP).sub.CGLnwherein: (IP).sub.CGLi, i=1, 2, . . . , n, represents an ionization potential of the charge generation material in charge generation layer i; and (b) a lower value of i indicating closer proximity to the substrate, and a greater value i indicates further away from the substrate.

Abstract: A family of photoreceptors for use in electrophotography are disclosed which contain a binary charge generation composition of oxytitanium phthalocyanine and copper phthalocyanine. The charge generation composition exhibits adjustable photosensitivity by adjusting a ratio between said oxytitanium phthalocyanine and said copper phthalocyanine. To optimize its performance, the charge generation composition is subject to an ammonia-modified complexation-mediated crystal transformation, and the resultant composition is characterized by Bragg diffraction angles (2.theta..+-.2.degree.) of 7.7, 9.4, 10.7, 13.3, 15.2, 15.7, 26.3, 27.4, and 28.4 degrees with respect to the CuK.alpha. characteristic X-ray wavelength at 1.54 .ANG. and absorption maxima centered around 615, 690, and 770 nm in the optical absorption spectrum.

Abstract: An electrophotographic photoreceptors having a protective layer which contains a specially cross-linked phenolic resin. The cross-linked phenolic resin contains both methylene ether linkages and methylene linkages that are provided such that the oxygen element content of the cross-linked phenolic resin contains no greater than 23.5 wt %, or more preferably between about 21 wt % and 23.5 wt %, of oxygen atoms. In a preferred embodiment, the specially cross-linked phenolic resin is formed by (a) raising the cross-linking temperature from 80.degree..+-.10.degree. C. to about 130.degree. C., in a cascading manner involving at least one intermediate treatment temperature; then (b) lowering the cross-linking temperature from about 130.degree. C. to 80.degree..+-.10.degree. C. The protective layer improves the chemical stability and mechanical strength of the electrophotographic photoreceptor while retaining the desired photoelectric properties thereof.