Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recov...Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir pro- duced fluid, fluorescent polyacrylamide microspheres P（AM-BA-AMCO）, which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribu- tion in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, NaaCO3, and dispersant. The bonding characteristics of microspheres were deter- mined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultra- violet irradiation in the produced fluid, even though theyhad experienced extrusion and deformation in the sand pack.展开更多
Distal radius fracture is the most common fracture site of the human skeleton[1]and often occurs in young people resulting from high energy injury caused by severe trauma.However,complex distal radial intra-articular ...Distal radius fracture is the most common fracture site of the human skeleton[1]and often occurs in young people resulting from high energy injury caused by severe trauma.However,complex distal radial intra-articular fractures(AO type C3)are relatively rare and account for about 5%of all distal radius fractures.[2]Fracture comminution at the joint surface is the primary manifestation of these fractures,followed by avulsion of the bone fragments with displacement seen at both the metacarpal and ulnar bone.Treatment of these displaced and unstable fractures remains a challenge.The nature of the articular surface fracture indicates the use of either the open or close reduction technique.Treatment protocols focus on extra-articular reduction and restoration of radial length,maintaining the volar tilt.[3,4]It has been noted that incongruity of the intra-articular distal radius fracture is relevant to the development of arthritis.[5,6]展开更多
基金supported by the National Natural Science Foundation of China (No.21273286)Doctoral Program Foundation of the Education Ministry (No.20130133110005)
文摘Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir pro- duced fluid, fluorescent polyacrylamide microspheres P（AM-BA-AMCO）, which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribu- tion in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, NaaCO3, and dispersant. The bonding characteristics of microspheres were deter- mined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultra- violet irradiation in the produced fluid, even though theyhad experienced extrusion and deformation in the sand pack.
文摘Distal radius fracture is the most common fracture site of the human skeleton[1]and often occurs in young people resulting from high energy injury caused by severe trauma.However,complex distal radial intra-articular fractures(AO type C3)are relatively rare and account for about 5%of all distal radius fractures.[2]Fracture comminution at the joint surface is the primary manifestation of these fractures,followed by avulsion of the bone fragments with displacement seen at both the metacarpal and ulnar bone.Treatment of these displaced and unstable fractures remains a challenge.The nature of the articular surface fracture indicates the use of either the open or close reduction technique.Treatment protocols focus on extra-articular reduction and restoration of radial length,maintaining the volar tilt.[3,4]It has been noted that incongruity of the intra-articular distal radius fracture is relevant to the development of arthritis.[5,6]
