High-cost equipment is often reused after maintenance, and whether the information before the maintenance can be used for the Remaining Useful Life （RUL） prediction after the maintenance is directly determined by th...High-cost equipment is often reused after maintenance, and whether the information before the maintenance can be used for the Remaining Useful Life （RUL） prediction after the maintenance is directly determined by the consistency of the degradation pattern before and after the maintenance. Aiming at this problem, an RUL prediction method based on the consistency test of a Wiener process is proposed. Firstly, the parameters of the Wiener process estimated by Maximum Likelihood Estimation （MLE） are proved to be biased, and a modified unbiased estimation method is proposed and verified by derivation and simulations. Then, the h statistic is constructed according to the reciprocal of the variation coefficient of the Wiener process, and the sampling distribution is derived. Meanwhile, a universal method for the consistency test is proposed based on the sampling distribution theorem, which is verified by simulation data and classical crack degradation data. Finally, based on the consistency test of the degradation model, a weighted fusion RUL prediction method is presented for the fuel pump of an airplane, and the validity of the presented method is verified by accurate computation results of real data, which provides a theoretical and practical guidance for engineers to predict the RUL of equipment after maintenance.展开更多
Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling...Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.展开更多
The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds（WSOCs） and their effects on ammonium sulfate（AS） and sodium chloride were investigated using a hygroscopicity ta...The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds（WSOCs） and their effects on ammonium sulfate（AS） and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer（HTDMA） in the relative humidity（RH） range of 5%–90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model（E-AIM） and Zdanovskii–Stokes–Robinson（ZSR） method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles.When organic content was dominant in the mixture（75%）, the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.展开更多
Aimed at the current treatment status of the polymer-flooding wastewater in Bohai oilfield, electrochemical technology used for polymer-degradation and oil-removal was researched. It formed the process flow of cyclone...Aimed at the current treatment status of the polymer-flooding wastewater in Bohai oilfield, electrochemical technology used for polymer-degradation and oil-removal was researched. It formed the process flow of cyclone mixed dosing → electrochemical removal oil → inclined tube removal oil → walnut shell filter, and a set of skid mounted wastewater containing polymer treatment plant was designed and manufactured, which was used for the field test of electrochemical treatment of wastewater containing polymer in offshore oilfield. The result shows that the oil removal rate of the electrochemical treatment process is over 98%, and the synergistic effect is significant especially used in conjunction with water clarifier of BHQ-04. When the amount of water clarifier is 50 - 150 mg/L, the oil content, the median particle diameter and the suspended solids content of the filtered water is 8 - 18 mg/L, 1.9 - 2.26 μm and 1.39 - 2.04 mg/L respectively, which reach the scene water quality standards for water injection.展开更多
The interactions between players of the prisoner's dilemma game are inferred using observed game data.All participants play the game with their counterparts and gain corresponding rewards during each round of the ...The interactions between players of the prisoner's dilemma game are inferred using observed game data.All participants play the game with their counterparts and gain corresponding rewards during each round of the game.The strategies of each player are updated asynchronously during the game.Two inference methods of the interactions between players are derived with naive mean-field(n MF)approximation and maximum log-likelihood estimation(MLE),respectively.Two methods are tested numerically also for fully connected asymmetric Sherrington-Kirkpatrick models,varying the data length,asymmetric degree,payoff,and system noise(coupling strength).We find that the mean square error of reconstruction for the MLE method is inversely proportional to the data length and typically half(benefit from the extra information of update times)of that by n MF.Both methods are robust to the asymmetric degree but work better for large payoffs.Compared with MLE,n MF is more sensitive to the strength of couplings and prefers weak couplings.展开更多
In this study, the temperature dependence of the heterogeneous uptake of acrylic acid on Arizona test dust （ATD） has been investigated within a temperature range of 255-315 K using a Knudsen cell reactor. Combined w...In this study, the temperature dependence of the heterogeneous uptake of acrylic acid on Arizona test dust （ATD） has been investigated within a temperature range of 255-315 K using a Knudsen cell reactor. Combined with diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） experiment, it was found that acrylic acid could adsorb on ATD via surface OH groups and convert to carboxylate on the particle surface. The kinetics study suggests that the initial true uptake coefficient （yt） of acrylic acid on ATD decreases from （4.02 ± 0.12） x 10-5 to （1.73 ± 0.05） x 10-5 with a temperature increase from 255 to 315 K. According to the temperature dependence of uptake coefficients, the enthalpy （AHobs） and entropy （ASobs） of uptake processes were determined to be -（9.60± 0.38） KJ/mol and -（121.55 ± 1.33） l.K/mol, respectively. The activation energy for desorption （Edes） was calculated to be （14.57 ± 0.60） KJ/mol. These results indicated that the heterogeneous uptake of acrylic acid on ATD surface was sensitive to temperature. The heterogeneous uptake on ATD could affect the concentration of acrylic acid in the atmosphere, especially at low temperature.展开更多
The blood-brain barrier （BBB） is a tight boundary formed between endothelial cells and astrocytes, which separates and protects brain from most pathogens as well as neural toxins in circulation. However, detailed mo...The blood-brain barrier （BBB） is a tight boundary formed between endothelial cells and astrocytes, which separates and protects brain from most pathogens as well as neural toxins in circulation. However, detailed molecular players involved in formation of BBB are not completely known. Dentin matrix protein I （DMP1）-proteoglycan （PG）, which is known to be involved in mineralization of bones and dentin, is also expressed in soft tissues including brain with unknown functions. In the present study, we reported that DMPI-PG was expressed in brain astrocytes and enriched in BBB units. The only glycosylation site of DMP1 is serine89 （S89） in the N-terminal domain of the protein in mouse. Mutant mice with DMP1 point mutations changing S89 to glycine （S89G）, which completely eradicated glycosylation of the protein, demonstrated severe BBB disruption. Another breed of DMP1 mutant mice, which lacked the C-terminal domain of DMP1, manifested normal BBB function. The polarity of S89G-DMP1 astrocytes was disrupted and cell-cell adhesion was loosened. Through a battery of analyses, we found that DMP1 glycosylation was critically required for astrocyte maturation both in vitro and in vivo. S89G-DMP1 mutant astrocytes failed to express aquaporin 4 and had reduced laminin and ZO1 expression, which resulted in disruption of BBB. Interestingly, overexpression of wild-type DMP1-PG in mouse brain driven by the nestin promoter elevated laminin and ZO1 expression beyond wild type levels and could effectively resisted intravenous mannitol-induced BBB reversible opening. Taken together, our study not only revealed a novel element, i.e., DMP1-PG, that reg- ulated BBB formation, but also assigned a new function to DMP1-PG.展开更多
The mammalian central nervous system (CNS) is considered an immune privileged system as it is separated from the periphery by the blood brain barrier (BBB). Yet, immune functions have been postulated to heavily influe...The mammalian central nervous system (CNS) is considered an immune privileged system as it is separated from the periphery by the blood brain barrier (BBB). Yet, immune functions have been postulated to heavily influence the functional state of the CNS, especially after injury or during neurodegeneration. There is controversy regarding whether adaptive immune responses are beneficial or detrimental to CNS injury repair. In this study, we utilized immunocompromised SCID mice and subjected them to spinal cord injury (SCI). We analyzed motor function, electrophysiology, histochemistry, and performed unbiased RNA-sequencing. SCID mice displayed improved CNS functional recovery compared to WT mice after SCI. Weighted gene-coexpression network analysis (WGCNA) of spinal cord transcriptomes revealed that SCID mice had reduced expression of immune function-related genes and heightened expression of neural transmission-related genes after SCI, which was confirmed by immunohistochemical analysis and was consistent with better functional recovery. Transcriptomic analyses also indicated heightened expression of neurotransmission-related genes before injury in SCID mice, suggesting that a steady state of immune-deficiency potentially led to CNS hyper-connectivity. Consequently, SCID mice without injury demonstrated worse performance in Morris water maze test. Taken together, not only reduced inflammation after injury but also dampened steady-state immune function without injury heightened the neurotransmission program, resulting in better or worse behavioral outcomes respectively. This study revealed the intricate relationship between immune and nervous systems, raising the possibility for therapeutic manipulation of neural function via immune modulation.展开更多
Alcohol consumption contributes to global mortality and cancer development.Acetaldehyde(ACE),the oxidized metabolite of alcohol,is highly reactive towards DNA,resulting in DNA adducts.ACE can be detoxified to acetate ...Alcohol consumption contributes to global mortality and cancer development.Acetaldehyde(ACE),the oxidized metabolite of alcohol,is highly reactive towards DNA,resulting in DNA adducts.ACE can be detoxified to acetate by acetaldehyde dehydrogenase type 2(ALDH2).ALDH2 deficiency can lead to ACE accumulation and DNA damage.展开更多
Multidimensional mechanical flexible organic crystals with tunable optoelectronic properties hold significant promise for practical application in complicated environmental conditions.Herein,based on a newly designed...Multidimensional mechanical flexible organic crystals with tunable optoelectronic properties hold significant promise for practical application in complicated environmental conditions.Herein,based on a newly designed“flexible”Schiff base small molecule with chirality,we presented a compatibly bendable and twistable organic single crystal with circularly polarized luminescence for the first time.First,the twodimensional elastic bending of the chiral crystal was realized at both room and liquid nitrogen temperatures,along with recoverable plastic twisting at room temperature.Besides,circular dichroism and circularly polarized luminescence spectroscopy were employed to characterize the chiral enantiomer in solution and the solid state.Our design strategy provides a new perspective for the future construction of chiroptical flexible crystal materials.展开更多
基金supported by the Aeronautical Science Foundation of China(No.201428960221)
文摘High-cost equipment is often reused after maintenance, and whether the information before the maintenance can be used for the Remaining Useful Life （RUL） prediction after the maintenance is directly determined by the consistency of the degradation pattern before and after the maintenance. Aiming at this problem, an RUL prediction method based on the consistency test of a Wiener process is proposed. Firstly, the parameters of the Wiener process estimated by Maximum Likelihood Estimation （MLE） are proved to be biased, and a modified unbiased estimation method is proposed and verified by derivation and simulations. Then, the h statistic is constructed according to the reciprocal of the variation coefficient of the Wiener process, and the sampling distribution is derived. Meanwhile, a universal method for the consistency test is proposed based on the sampling distribution theorem, which is verified by simulation data and classical crack degradation data. Finally, based on the consistency test of the degradation model, a weighted fusion RUL prediction method is presented for the fuel pump of an airplane, and the validity of the presented method is verified by accurate computation results of real data, which provides a theoretical and practical guidance for engineers to predict the RUL of equipment after maintenance.
基金Financial support from the Natural Science Foundation of Sichuan Province(2022NSFSC0030)National Natural Science Foundation of China(U1762218)is gratefully acknowledged.
文摘Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.
基金supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (No. XDB05010400)the National Natural Science Foundation of China (Nos. 21477134, 41175119, 21473009)
文摘The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds（WSOCs） and their effects on ammonium sulfate（AS） and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer（HTDMA） in the relative humidity（RH） range of 5%–90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model（E-AIM） and Zdanovskii–Stokes–Robinson（ZSR） method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles.When organic content was dominant in the mixture（75%）, the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.
文摘Aimed at the current treatment status of the polymer-flooding wastewater in Bohai oilfield, electrochemical technology used for polymer-degradation and oil-removal was researched. It formed the process flow of cyclone mixed dosing → electrochemical removal oil → inclined tube removal oil → walnut shell filter, and a set of skid mounted wastewater containing polymer treatment plant was designed and manufactured, which was used for the field test of electrochemical treatment of wastewater containing polymer in offshore oilfield. The result shows that the oil removal rate of the electrochemical treatment process is over 98%, and the synergistic effect is significant especially used in conjunction with water clarifier of BHQ-04. When the amount of water clarifier is 50 - 150 mg/L, the oil content, the median particle diameter and the suspended solids content of the filtered water is 8 - 18 mg/L, 1.9 - 2.26 μm and 1.39 - 2.04 mg/L respectively, which reach the scene water quality standards for water injection.
基金supported by the National Natural Science Foundation of China(Grant Nos.11705079 and 11705279)the Scientific Research Foundation of Nanjing University of Posts and Telecommunications(Grant Nos.NY221101 and NY222134)the Science and Technology Innovation Training Program(Grant No.STITP 202210293044Z)。
文摘The interactions between players of the prisoner's dilemma game are inferred using observed game data.All participants play the game with their counterparts and gain corresponding rewards during each round of the game.The strategies of each player are updated asynchronously during the game.Two inference methods of the interactions between players are derived with naive mean-field(n MF)approximation and maximum log-likelihood estimation(MLE),respectively.Two methods are tested numerically also for fully connected asymmetric Sherrington-Kirkpatrick models,varying the data length,asymmetric degree,payoff,and system noise(coupling strength).We find that the mean square error of reconstruction for the MLE method is inversely proportional to the data length and typically half(benefit from the extra information of update times)of that by n MF.Both methods are robust to the asymmetric degree but work better for large payoffs.Compared with MLE,n MF is more sensitive to the strength of couplings and prefers weak couplings.
基金supported by the National Natural Science Foundation of China(Nos.41405118 and 91544227)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(No.XDB05010400)+1 种基金the National Key Technology Support Plan Projects(No.2014BAC16B01)the Basic Scientific Research Progress of the Chinese Academy of Meteorological Sciences(No.2014Y007)
文摘In this study, the temperature dependence of the heterogeneous uptake of acrylic acid on Arizona test dust （ATD） has been investigated within a temperature range of 255-315 K using a Knudsen cell reactor. Combined with diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） experiment, it was found that acrylic acid could adsorb on ATD via surface OH groups and convert to carboxylate on the particle surface. The kinetics study suggests that the initial true uptake coefficient （yt） of acrylic acid on ATD decreases from （4.02 ± 0.12） x 10-5 to （1.73 ± 0.05） x 10-5 with a temperature increase from 255 to 315 K. According to the temperature dependence of uptake coefficients, the enthalpy （AHobs） and entropy （ASobs） of uptake processes were determined to be -（9.60± 0.38） KJ/mol and -（121.55 ± 1.33） l.K/mol, respectively. The activation energy for desorption （Edes） was calculated to be （14.57 ± 0.60） KJ/mol. These results indicated that the heterogeneous uptake of acrylic acid on ATD surface was sensitive to temperature. The heterogeneous uptake on ATD could affect the concentration of acrylic acid in the atmosphere, especially at low temperature.
基金We thank Dr. Chunlin Qin （Bayler colleage of dentistry, Texas A＆M University） for providing us DMP1 antibody. This study was supported by China National Key Research and Development Program （2016YFA0100801 YS）, and the National Natural Science Foundation of China （Grant Nos. 8133030 YS and 31620103904 YS）, and grants： 2016YFC102705 YS 2014BAI04B07 WZL+1 种基金 81470715 YS TJ1504219036 WZL： 2017BR009 YS.
文摘The blood-brain barrier （BBB） is a tight boundary formed between endothelial cells and astrocytes, which separates and protects brain from most pathogens as well as neural toxins in circulation. However, detailed molecular players involved in formation of BBB are not completely known. Dentin matrix protein I （DMP1）-proteoglycan （PG）, which is known to be involved in mineralization of bones and dentin, is also expressed in soft tissues including brain with unknown functions. In the present study, we reported that DMPI-PG was expressed in brain astrocytes and enriched in BBB units. The only glycosylation site of DMP1 is serine89 （S89） in the N-terminal domain of the protein in mouse. Mutant mice with DMP1 point mutations changing S89 to glycine （S89G）, which completely eradicated glycosylation of the protein, demonstrated severe BBB disruption. Another breed of DMP1 mutant mice, which lacked the C-terminal domain of DMP1, manifested normal BBB function. The polarity of S89G-DMP1 astrocytes was disrupted and cell-cell adhesion was loosened. Through a battery of analyses, we found that DMP1 glycosylation was critically required for astrocyte maturation both in vitro and in vivo. S89G-DMP1 mutant astrocytes failed to express aquaporin 4 and had reduced laminin and ZO1 expression, which resulted in disruption of BBB. Interestingly, overexpression of wild-type DMP1-PG in mouse brain driven by the nestin promoter elevated laminin and ZO1 expression beyond wild type levels and could effectively resisted intravenous mannitol-induced BBB reversible opening. Taken together, our study not only revealed a novel element, i.e., DMP1-PG, that reg- ulated BBB formation, but also assigned a new function to DMP1-PG.
基金National Key Basic Research Program from MOST, China (Nos. 2016YFA0100801 and 2014CB964602)the National Natural Science Foundation of China (Grant Nos. 81330030, 31620103904 and 81650110524)+1 种基金the National Institutes of Health (NIH5R21NS095184-02)the "RNAseq on Single Cell and beyond Core "in the Developme ntal Disabilities Research Center (NIH5U54HD087101-02) at University of California Los Angeles.
文摘The mammalian central nervous system (CNS) is considered an immune privileged system as it is separated from the periphery by the blood brain barrier (BBB). Yet, immune functions have been postulated to heavily influence the functional state of the CNS, especially after injury or during neurodegeneration. There is controversy regarding whether adaptive immune responses are beneficial or detrimental to CNS injury repair. In this study, we utilized immunocompromised SCID mice and subjected them to spinal cord injury (SCI). We analyzed motor function, electrophysiology, histochemistry, and performed unbiased RNA-sequencing. SCID mice displayed improved CNS functional recovery compared to WT mice after SCI. Weighted gene-coexpression network analysis (WGCNA) of spinal cord transcriptomes revealed that SCID mice had reduced expression of immune function-related genes and heightened expression of neural transmission-related genes after SCI, which was confirmed by immunohistochemical analysis and was consistent with better functional recovery. Transcriptomic analyses also indicated heightened expression of neurotransmission-related genes before injury in SCID mice, suggesting that a steady state of immune-deficiency potentially led to CNS hyper-connectivity. Consequently, SCID mice without injury demonstrated worse performance in Morris water maze test. Taken together, not only reduced inflammation after injury but also dampened steady-state immune function without injury heightened the neurotransmission program, resulting in better or worse behavioral outcomes respectively. This study revealed the intricate relationship between immune and nervous systems, raising the possibility for therapeutic manipulation of neural function via immune modulation.
基金supported by grants from the National Nature Science Foundation of China(No.82172565,81620108022,81872245,91129303,991729302,81572759,,31900441,82003069,82103571,882002941,82072570,91129733,81502702).
文摘Alcohol consumption contributes to global mortality and cancer development.Acetaldehyde(ACE),the oxidized metabolite of alcohol,is highly reactive towards DNA,resulting in DNA adducts.ACE can be detoxified to acetate by acetaldehyde dehydrogenase type 2(ALDH2).ALDH2 deficiency can lead to ACE accumulation and DNA damage.
基金supported by the National Natural Science Foundation of China(grant no.22178254)the Key R&D Program of Hebei Province,China(grant no.21282602Z)the Tianjin Natural Science Foundation,China(grant no.21JCZJC00400).
文摘Multidimensional mechanical flexible organic crystals with tunable optoelectronic properties hold significant promise for practical application in complicated environmental conditions.Herein,based on a newly designed“flexible”Schiff base small molecule with chirality,we presented a compatibly bendable and twistable organic single crystal with circularly polarized luminescence for the first time.First,the twodimensional elastic bending of the chiral crystal was realized at both room and liquid nitrogen temperatures,along with recoverable plastic twisting at room temperature.Besides,circular dichroism and circularly polarized luminescence spectroscopy were employed to characterize the chiral enantiomer in solution and the solid state.Our design strategy provides a new perspective for the future construction of chiroptical flexible crystal materials.
