Abstract: The present disclosure provides an N protein epitope mutation marker for preparing an epitope deletion-marked vaccine strain of type II porcine reproductive and respiratory syndrome virus (PRRSV) and use thereof, belonging to the technical field of biological products. In the mutation marker, one or more amino acids are mutated based on an epitope sequence at positions 92 to 103 of a C-terminal of an N protein of the type II PRRSV; and the epitope mutation marker has an amino acid sequence shown in SEQ ID NO: 1, where X1 is selected from the group consisting of T, P, and A; and X2 is selected from the group consisting of V and A.

Abstract: A reconstruction method for a pore structure of a core with micro-CT (Computed Tomography) is provided. With utilizing a FIB-SEM (Focused Ion Beam-Scanning Electron Microscope) experiment, an actual porosity corresponding to a grey level in micro-CT results is obtained, so as to establish a relationship between the grey level of a micro-CT image and the porosity. Thereafter, according to the above relationship, a certain porosity is assigned to each pixel in the micro-CT image, so as to establish a soft segmentation method of the pore structure. The reconstruction method provided by the present invention discloses a soft segmentation method for digital reconstruction of the pore structure of the core combined with FIB-SEM data and micro-CT data, and establishes a fractional digital pore structure model of the core, which further improves a matching degree between the digital pore structure model of the core and an actual core.

Abstract: An isotope nuclear magnetic method for analyzing ineffective water absorption of rock pores includes steps of: saturating core pores of a core sample with a wetting phase fluid of water H2O, and obtaining a core T2 spectrum after being saturated with the water; re-saturating the core pores with a wetting phase fluid of heavy water D2O, and obtaining a rock baseline T2 spectrum; injecting fluorinated oil into the core sample saturated with the heavy water; injecting the water H2O, simulating a water injection process, and injecting the fluorinated oil, so as to analyze a content of immobile water and obtain a residual T2 spectrum, wherein a range formed by a difference between the residual T2 spectrum and the rock baseline T2 spectrum is an ineffective water absorption portion of the rock pores, and an ineffective water absorption amount is obtained.

Abstract: An isotope nuclear magnetic method for analyzing ineffective water absorption of rock pores includes steps of: saturating core pores of a core sample with a wetting phase fluid of water H2O, and obtaining a core T2 spectrum after being saturated with the water; re-saturating the core pores with a wetting phase fluid of heavy water D2O, and obtaining a rock baseline T2 spectrum; injecting fluorinated oil into the core sample saturated with the heavy water; injecting the water H2O, simulating a water injection process, and injecting the fluorinated oil, so as to analyze a content of immobile water and obtain a residual T2 spectrum, wherein a range formed by a difference between the residual T2 spectrum and the rock baseline T2 spectrum is an ineffective water absorption portion of the rock pores, and an ineffective water absorption amount is obtained.

Abstract: A reconstruction method for a pore structure of a core with micro-CT (Computed Tomography) is provided. With utilizing a FIB-SEM (Focused Ion Beam-Scanning Electron Microscope) experiment, an actual porosity corresponding to a grey level in micro-CT results is obtained, so as to establish a relationship between the grey level of a micro-CT image and the porosity. Thereafter, according to the above relationship, a certain porosity is assigned to each pixel in the micro-CT image, so as to establish a soft segmentation method of the pore structure. The reconstruction method provided by the present invention discloses a soft segmentation method for digital reconstruction of the pore structure of the core combined with FIB-SEM data and micro-CT data, and establishes a fractional digital pore structure model of the core, which further improves a matching degree between the digital pore structure model of the core and an actual core.