As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and g...As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas well.However,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the screen.To explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined method.According to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was analyzed.The results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of clogging.In the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control unit.In the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the opening.In the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage rate.The microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen and sand prevention selection.展开更多
Based on single-cell sequencing of the hippocampi of 5×familiar Alzheimer's disease(5×FAD)and wild type mice at 2-,12-,and 24-month of age,we found an increased percentage of microglia in aging and Alzhe...Based on single-cell sequencing of the hippocampi of 5×familiar Alzheimer's disease(5×FAD)and wild type mice at 2-,12-,and 24-month of age,we found an increased percentage of microglia in aging and Alzheimer's disease(AD)mice.Blood brain barrier injury may also have contributed to this increase.Immune regulation by microglia plays a major role in the progression of aging and AD,according to the functions of 41 intersecting differentially expressed genes in microglia.Signaling crosstalk between C−C motif chemokine ligand(CCL)and major histocompatibility complex-1 bridges intercellular communication in the hippocampus during aging and AD.The amyloid precursor protein(APP)and colony stimulating factor(CSF)signals drive 5×FAD to deviate from aging track to AD occurrence among intercellular communication in hippocampus.Microglia are involved in the progression of aging and AD can be divided into 10 functional types.The strength of the interaction among microglial subtypes weakened with aging,and the CCL and CSF signaling pathways were the fundamental bridge of communication among microglial subtypes.展开更多
文摘As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas well.However,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the screen.To explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined method.According to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was analyzed.The results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of clogging.In the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control unit.In the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the opening.In the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage rate.The microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen and sand prevention selection.
基金supported by grants from the Key R&D Plan of the Science and Technology Plan of Tibet Autonomous Region,China(Grant No.:XZ202201ZY0026G)the Science and Technology Cooperation Project of Shandong Provincial Department of Science and Technology for Counterpart Assistance to Tibet,China(Grant No.:YDZX2021083)+1 种基金the National Natural Science Foundation of China(Grant No.:82205078)the Natural Science Foundation of Shandong Province,China(Grant No.:ZR2021QH157).
文摘Based on single-cell sequencing of the hippocampi of 5×familiar Alzheimer's disease(5×FAD)and wild type mice at 2-,12-,and 24-month of age,we found an increased percentage of microglia in aging and Alzheimer's disease(AD)mice.Blood brain barrier injury may also have contributed to this increase.Immune regulation by microglia plays a major role in the progression of aging and AD,according to the functions of 41 intersecting differentially expressed genes in microglia.Signaling crosstalk between C−C motif chemokine ligand(CCL)and major histocompatibility complex-1 bridges intercellular communication in the hippocampus during aging and AD.The amyloid precursor protein(APP)and colony stimulating factor(CSF)signals drive 5×FAD to deviate from aging track to AD occurrence among intercellular communication in hippocampus.Microglia are involved in the progression of aging and AD can be divided into 10 functional types.The strength of the interaction among microglial subtypes weakened with aging,and the CCL and CSF signaling pathways were the fundamental bridge of communication among microglial subtypes.
