Abstract: Provided in the present disclosure are an IGBT device backside structure and a preparation method therefor, and an IGBT device, the IGBT device backside structure comprising a buffer layer, the buffer layer comprising a first activation efficiency buffer area corresponding to an active area of the IGBT device and a second activation efficiency buffer area corresponding to a terminal area of the IGBT device, the activation efficiency of the first activation efficiency buffer area being less than the activation efficiency of the second activation efficiency buffer area.

Abstract: A communication establishment method including acquiring a first communication number of a current communication terminal; acquiring an input image, obtaining an information code according to the image, the information code being corresponding to a second communication number; sending call information to a predetermined server, the call information being attached with the first communication number and the information code. The current communication terminal obtains the information code according to the image, provides the information code and the first communication number of the current communication terminal to the predetermined server to establish a communication between the current communication terminal that uses the first communication number and a communication terminal that uses the second communication number.

Abstract: A communication establishment method including acquiring a first communication number of a current communication terminal; acquiring an input image, obtaining an information code according to the image, the information code being corresponding to a second communication number; sending call information to a predetermined server, the call information being attached with the first communication number and the information code. The current communication terminal obtains the information code according to the image, provides the information code and the first communication number of the current communication terminal to the predetermined server to establish a communication between the current communication terminal that uses the first communication number and a communication terminal that uses the second communication number.

Abstract: A communication establishment method including acquiring a first communication number of a current communication terminal; acquiring an input image, obtaining an information code according to the image, the information code being corresponding to a second communication number; sending call information to a predetermined server, the call information being attached with the first communication number and the information code. The current communication terminal obtains the information code according to the image, provides the information code and the first communication number of the current communication terminal to the predetermined server to establish a communication between the current communication terminal that uses the first communication number and a communication terminal that uses the second communication number.

Abstract: A communication establishment method including acquiring a first communication number of a current communication terminal; acquiring an input image, obtaining an information code according to the image, the information code being corresponding to a second communication number; sending call information to a predetermined server, the call information being attached with the first communication number and the information code. The current communication terminal obtains the information code according to the image, provides the information code and the first communication number of the current communication terminal to the predetermined server to establish a communication between the current communication terminal that uses the first communication number and a communication terminal that uses the second communication number.

Abstract: A method for an explosion welding process to form composite pipes, such as for nuclear power equipment. The explosive welding process includes: (1) An explosives preparation method in which low detonation velocity explosives are produced by using powdery emulsion explosives as a base. The base is mixed completely and evenly with a certain amount of powdered pearl salt, wherein the size of the pearl salt particle is 100-200 mesh, and the ratio of emulsion explosives versus pearl salt is between about 3-5:1. (2) A method of inhibiting the negative influence on welding quality caused by the gap between a base tube and a mold, wherein: the roughness of the base tube outer surface is kept less than that of the mold's inner surface, with the difference in surface roughness being maintained within two-grades. In certain cases, a layer of 1.0.±.0.1 mm copper may be added between the outer wall of a base tube and the inner wall of the mold.

Abstract: A method for an explosion welding process to form composite pipes, such as for nuclear power equipment. The explosive welding process includes: (1) An explosives preparation method in which low detonation velocity explosives are produced by using powdery emulsion explosives as a base. The base is mixed completely and evenly with a certain amount of powdered pearl salt, wherein the size of pearl salt particle is 100-200 mesh, and the ratio of emulsion explosives versus pearl salt is between about 3-5:1. (2) An experimental formula for determining the diameter gap between an inner lining tube and its base tube, which is s=?·r or s=k?·r. and (3) A method of inhibiting the negative influence on welding quality caused by the gap between a base tube and a mold, wherein: the roughness of the base tube outer surface is kept less than that of the mold's inner surface, with the difference in surface roughness being maintained within two-grades. In certain cases, a layer of 1.0±0.

Abstract: A blast shield formed as a multilayer sandwich of composite material configured to provide protection to bystanders in close proximity to operation of a linear shaped charge. An exemplary embodiment may be used to shield passengers when explosively cutting an emergency door in airliners. The composite material forming a blast shield may have two types of composition: the first type contains a layer of carbon fiber cloth, a layer of natural rubber and a layer of Kevlar fiber cloth, from the inside out in order. The second type contains a layer of carbon fiber cloth, a layer of Kevlar fiber cloth and a layer of polyurethane rubber, from the inside out in order. Both types typically use epoxy resin as the bond between each layer. Through the composition of fiber and rubber, embodiments can effectively block the spread of explosive shock waves, reduce the noise, decrease the weight of protective devices, and avoid forming wounding debris.