Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and ...Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and intensity of precipitation.A large-scale model experiment was conducted on a self-designed physical simulation experiment platform to investigate the failure and instability of high-steep rock slopes under unsaturated conditions.The real-time reproduction of the progressive failure process in high-steep rock slopes enabled the determination of the critical rainfall intensity and revealed the mechanism underlying slope instability.Experiment results indicated that rainfall may be the primary factor contributing to rock mass instability,while continuous pillar mining exacerbates the extent of rock mass failure.The critical failure stage of high-steep rock slopes occurs at a rainfall intensity of 40 mm/h,whereas a rainfall exceeding 50 mm can induce critical instability and precipitation reaching up to 60 mm will result in slope failure.The improved region growing segmentation method(IRGSM)was subsequently employed for image recognition of rock mass deformation in underground mines.Herein an error comparison with the simple linear iterative cluster(SLIC)superpixel method and the original region growing segmentation method(ORGSM)showed that the average identification error in the X and Y directions by the method was reduced significantly(1.82%and 1.80%in IRGSM;4.70%and 6.26%in SLIC;9.45%and 12.40%in ORGSM).Ultimately,the relationship between rainfall intensity and failure probability was analyzed using the Monte Carlo method.Moreover,the stability assessment criteria of rock slope under unsaturated condition were quantitatively and accurately evaluated.展开更多
Hyperhomocysteinemia(Hhcy) is an independent risk factor for Alzheimer's disease(AD). Visual dysfunction is commonly found and is positively correlated with the severity of cognitive defects in AD patients. Our pr...Hyperhomocysteinemia(Hhcy) is an independent risk factor for Alzheimer's disease(AD). Visual dysfunction is commonly found and is positively correlated with the severity of cognitive defects in AD patients. Our previous study demonstrated that Hhcy induces memory deficits with AD-like tau and amyloid-b(Ab) pathologies in the hippocampus, and supplementation with folate and vitamin B12(FB) prevents the Hhcy-induced AD-like pathologies in the hippocampus. Here, we investigated whether Hhcy also induces AD-like pathologies in the retina and the effects of FB. An Hhcy rat model was produced by vena caudalis injection of homocysteine for14 days, and the effects of FB were assessed by simultaneous supplementation with FB in drinking water. We found that Hhcy induced vessel damage with Ab and taupathologies in the retina, while simultaneous supplementation with FB remarkably attenuated the Hhcy-induced tau hyperphosphorylation at multiple AD-related sites and Ab accumulation in the retina. The mechanisms involved downregulation of amyloid precursor protein(APP), presenilin-1, beta-site APP-cleaving enzyme 1, and protein phosphatase-2 A. Our data suggest that the retina may serve as a window for evaluating the effects of FB on hyperhomocysteinemia-induced Alzheimer-like pathologies.展开更多
Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt format...Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.展开更多
Intense precipitation infiltration and intricate excavation processes are crucial factors that impact the stability and security of towering and steep rock slopes within mining sites.The primary aim of this research w...Intense precipitation infiltration and intricate excavation processes are crucial factors that impact the stability and security of towering and steep rock slopes within mining sites.The primary aim of this research was to investigate the progression of cumulative failure within a cracked rock formation,considering the combined effects of precipitation and excavation activities.The study was conducted in the Huangniuqian eastern mining area of the Dexing Copper Mine in Jiangxi Province,China.An engineering geological investigation was conducted,a physical model experiment was performed,numerical calculations and theoretical analysis were conducted using the matrix discrete element method(Mat-DEM),and the deformation characteristics and the effect of the slope angle of a fractured rock mass under different scenarios were examined.The failure and instability mechanisms of the fractured rock mass under three slope angle models were analyzed.The experimental results indicate that as the slope angle increases,the combined effect of rainfall infiltration and excavation unloading is reduced.A novel approach to simulating unsaturated seepage in a rock mass,based on the van Genuchten model(VGM),has been developed.Compared to the vertical displacement observed in a similar physical experiment,the average relative errors associated with the slope angles of 45,50,and 55were 2.094%,1.916%,and 2.328%,respectively.Accordingly,the combined effect of rainfall and excavation was determined using the proposed method.Moreover,the accuracy of the numerical simulation was validated.The findings contribute to the seepage field in a meaningful way,offering insight that can inform and enhance existing methods and theories for research on the underlying mechanism of ultra-high and steep rock slope instability,which can inform the development of more effective risk management strategies.展开更多
Underground salt cavern CO_(2) storage(SCCS)offers the dual benefits of enabling extensive CO_(2) storage and facilitating the utilization of CO_(2) resources while contributing the regulation of the carbon market.Its...Underground salt cavern CO_(2) storage(SCCS)offers the dual benefits of enabling extensive CO_(2) storage and facilitating the utilization of CO_(2) resources while contributing the regulation of the carbon market.Its economic and operational advantages over traditional carbon capture,utilization,and storage(CCUS)projects make SCCS a more cost-effective and flexible option.Despite the widespread use of salt caverns for storing various substances,differences exist between SCCS and traditional salt cavern energy storage in terms of gas-tightness,carbon injection,brine extraction control,long-term carbon storage stability,and site selection criteria.These distinctions stem from the unique phase change characteristics of CO_(2) and the application scenarios of SCCS.Therefore,targeted and forward-looking scientific research on SCCS is imperative.This paper introduces the implementation principles and application scenarios of SCCS,emphasizing its connections with carbon emissions,carbon utilization,and renewable energy peak shaving.It delves into the operational characteristics and economic advantages of SCCS compared with other CCUS methods,and addresses associated scientific challenges.In this paper,we establish a pressure equation for carbon injection and brine extraction,that considers the phase change characteristics of CO_(2),and we analyze the pressure during carbon injection.By comparing the viscosities of CO_(2) and other gases,SCCS’s excellent sealing performance is demonstrated.Building on this,we develop a long-term stability evaluation model and associated indices,which analyze the impact of the injection speed and minimum operating pressure on stability.Field countermeasures to ensure stability are proposed.Site selection criteria for SCCS are established,preliminary salt mine sites suitable for SCCS are identified in China,and an initial estimate of achievable carbon storage scale in China is made at over 51.8-77.7 million tons,utilizing only 20%-30%volume of abandoned salt caverns.This paper addresses key scientific and engineering challenges facing SCCS and determines crucial technical parameters,such as the operating pressure,burial depth,and storage scale,and it offers essential guidance for implementing SCCS projects in China.展开更多
Centrifugal separation machinery,especially those with vertical rotor structures and ball joint constraints,face significant operational stability challenges due to shaft center position and vibration issues,as well a...Centrifugal separation machinery,especially those with vertical rotor structures and ball joint constraints,face significant operational stability challenges due to shaft center position and vibration issues,as well as strong lateral crosscoupling characteristics from their complex support structure.To address these challenges,this study proposes a novel real-time control method for the center position of a centrifuge rotor.The method integrates a variable step-size least mean square notch filter(VSLNF),a tracking differentiator(TD),and an all-coefficient adaptive control(ACAC)based on a characteristic model.The method dynamically updates the characteristic model coefficients to adapt to system changes,achieving precise shaft center control.The VSLNF removes synchronous frequency vibrations,the TD handles complex dynamics,and the ACAC adapts to varying conditions.This approach is particularly suitable for centrifuges with complex support structures,differing from conventional magnetically levitated rotor systems.The numerical study establishes a finite element model of the centrifuge and designs an adaptive controller to adjust the rotor position in real-time.The combination of ACAC with VSLNF and TD allows for effective vibration control under both constant and variable speed conditions,significantly reducing high-speed vibrations after crossing critical speeds.Experimental results demonstrate that the method effectively controls rotor displacement and reduces vibrations,offering a novel solution for vibration control in industrial rotating machinery with significant engineering application value.展开更多
Urban development thrives from technology inflows,which refers to the transfer of highvalue technology from various cities to local recipients.The asymmetry of technical information-rooted in the tacit knowledge inher...Urban development thrives from technology inflows,which refers to the transfer of highvalue technology from various cities to local recipients.The asymmetry of technical information-rooted in the tacit knowledge inherent in technology-mandates that technology transfer is heavily dependent on interactions and communication among talented individuals.This study examines the effect of China's high-speed railway(HSR)on technology inflow,with an emphasis on talent interaction in the technology transfer process.The findings suggest that HSR mitigates cross-city commuting costs and facilitates face-to-face interactions between talent,thereby fostering an increase in technology inflows to various cities."Talent"use HSR to transfer knowledge to cities teeming with such talent resources.Concurrently,areas with robust intellectual property rights protection witness an upsurge in intercity technology transfer via HsR.This study elucidates the macro-mechanism of urban technology flow from the perspective of public transportation offering valuable insights for technology market infrastructure and services.展开更多
基金the Research Fund of National Natural Science Foundation of China(NSFC)(No.42277154)the project supported by graduate research and innovation foundation of Chongqing,China(No.CYB22023)+3 种基金Guizhou Province Science and Technology Planning Project(No.Guizhou science and technology cooperation support[2022]common 229)National Natural Science Foundation of Shandong Province of China(NSFC)(No.ZR2022ME188)the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.SKLCRSM22KF009)Open Fund of National Engineering and Technology Research Center for Development and Utilization of Phosphate Resources of China(No.NECP 2022-04).
文摘Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and intensity of precipitation.A large-scale model experiment was conducted on a self-designed physical simulation experiment platform to investigate the failure and instability of high-steep rock slopes under unsaturated conditions.The real-time reproduction of the progressive failure process in high-steep rock slopes enabled the determination of the critical rainfall intensity and revealed the mechanism underlying slope instability.Experiment results indicated that rainfall may be the primary factor contributing to rock mass instability,while continuous pillar mining exacerbates the extent of rock mass failure.The critical failure stage of high-steep rock slopes occurs at a rainfall intensity of 40 mm/h,whereas a rainfall exceeding 50 mm can induce critical instability and precipitation reaching up to 60 mm will result in slope failure.The improved region growing segmentation method(IRGSM)was subsequently employed for image recognition of rock mass deformation in underground mines.Herein an error comparison with the simple linear iterative cluster(SLIC)superpixel method and the original region growing segmentation method(ORGSM)showed that the average identification error in the X and Y directions by the method was reduced significantly(1.82%and 1.80%in IRGSM;4.70%and 6.26%in SLIC;9.45%and 12.40%in ORGSM).Ultimately,the relationship between rainfall intensity and failure probability was analyzed using the Monte Carlo method.Moreover,the stability assessment criteria of rock slope under unsaturated condition were quantitatively and accurately evaluated.
基金supported in part by the Natural Science Foundation of China (91632305, 91632111, 31730035, and 81721005)by the Ministry of Science and Technology of China (2016YFC1305800)
文摘Hyperhomocysteinemia(Hhcy) is an independent risk factor for Alzheimer's disease(AD). Visual dysfunction is commonly found and is positively correlated with the severity of cognitive defects in AD patients. Our previous study demonstrated that Hhcy induces memory deficits with AD-like tau and amyloid-b(Ab) pathologies in the hippocampus, and supplementation with folate and vitamin B12(FB) prevents the Hhcy-induced AD-like pathologies in the hippocampus. Here, we investigated whether Hhcy also induces AD-like pathologies in the retina and the effects of FB. An Hhcy rat model was produced by vena caudalis injection of homocysteine for14 days, and the effects of FB were assessed by simultaneous supplementation with FB in drinking water. We found that Hhcy induced vessel damage with Ab and taupathologies in the retina, while simultaneous supplementation with FB remarkably attenuated the Hhcy-induced tau hyperphosphorylation at multiple AD-related sites and Ab accumulation in the retina. The mechanisms involved downregulation of amyloid precursor protein(APP), presenilin-1, beta-site APP-cleaving enzyme 1, and protein phosphatase-2 A. Our data suggest that the retina may serve as a window for evaluating the effects of FB on hyperhomocysteinemia-induced Alzheimer-like pathologies.
基金financial support from the National Key Research and Development Program of China(No.2024YFB4007100)the Basic ForwardLooking Project of the Sinopec Science and Technology Department,“Research on the Long-Term Sealing Mechanism of Multi-layer Salt Cavern Hydrogen Storage”(No.P24197-4)。
文摘Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.
基金the Research Fund of National Natural Science Foundation of China(NSFC)(Grant Nos.42477142 and 42277154)the Project of Slope Safety Control and Disaster Prevention Technology Innovation team of“Youth Innovation Talent Introduction and Education Plan”of Shandong Colleges and Universities(Grant No.Lu Jiao Ke Han[2021]No.51)。
文摘Intense precipitation infiltration and intricate excavation processes are crucial factors that impact the stability and security of towering and steep rock slopes within mining sites.The primary aim of this research was to investigate the progression of cumulative failure within a cracked rock formation,considering the combined effects of precipitation and excavation activities.The study was conducted in the Huangniuqian eastern mining area of the Dexing Copper Mine in Jiangxi Province,China.An engineering geological investigation was conducted,a physical model experiment was performed,numerical calculations and theoretical analysis were conducted using the matrix discrete element method(Mat-DEM),and the deformation characteristics and the effect of the slope angle of a fractured rock mass under different scenarios were examined.The failure and instability mechanisms of the fractured rock mass under three slope angle models were analyzed.The experimental results indicate that as the slope angle increases,the combined effect of rainfall infiltration and excavation unloading is reduced.A novel approach to simulating unsaturated seepage in a rock mass,based on the van Genuchten model(VGM),has been developed.Compared to the vertical displacement observed in a similar physical experiment,the average relative errors associated with the slope angles of 45,50,and 55were 2.094%,1.916%,and 2.328%,respectively.Accordingly,the combined effect of rainfall and excavation was determined using the proposed method.Moreover,the accuracy of the numerical simulation was validated.The findings contribute to the seepage field in a meaningful way,offering insight that can inform and enhance existing methods and theories for research on the underlying mechanism of ultra-high and steep rock slope instability,which can inform the development of more effective risk management strategies.
基金supported by the National Natural Science Foundation of China(52074046,52122403,51834003,and 52274073)the Graduate Research and Innovation Foundation of Chongqing(CYB22023)+2 种基金the Chongqing Talents Plan for Young Talents(cstc2022ycjh-bgzxm0035)Hunan Institute of Engineering(21RC025 and XJ2005)Hunan Province Education Department(21B0664).
文摘Underground salt cavern CO_(2) storage(SCCS)offers the dual benefits of enabling extensive CO_(2) storage and facilitating the utilization of CO_(2) resources while contributing the regulation of the carbon market.Its economic and operational advantages over traditional carbon capture,utilization,and storage(CCUS)projects make SCCS a more cost-effective and flexible option.Despite the widespread use of salt caverns for storing various substances,differences exist between SCCS and traditional salt cavern energy storage in terms of gas-tightness,carbon injection,brine extraction control,long-term carbon storage stability,and site selection criteria.These distinctions stem from the unique phase change characteristics of CO_(2) and the application scenarios of SCCS.Therefore,targeted and forward-looking scientific research on SCCS is imperative.This paper introduces the implementation principles and application scenarios of SCCS,emphasizing its connections with carbon emissions,carbon utilization,and renewable energy peak shaving.It delves into the operational characteristics and economic advantages of SCCS compared with other CCUS methods,and addresses associated scientific challenges.In this paper,we establish a pressure equation for carbon injection and brine extraction,that considers the phase change characteristics of CO_(2),and we analyze the pressure during carbon injection.By comparing the viscosities of CO_(2) and other gases,SCCS’s excellent sealing performance is demonstrated.Building on this,we develop a long-term stability evaluation model and associated indices,which analyze the impact of the injection speed and minimum operating pressure on stability.Field countermeasures to ensure stability are proposed.Site selection criteria for SCCS are established,preliminary salt mine sites suitable for SCCS are identified in China,and an initial estimate of achievable carbon storage scale in China is made at over 51.8-77.7 million tons,utilizing only 20%-30%volume of abandoned salt caverns.This paper addresses key scientific and engineering challenges facing SCCS and determines crucial technical parameters,such as the operating pressure,burial depth,and storage scale,and it offers essential guidance for implementing SCCS projects in China.
基金supported by the National Natural Science Foundation of China(Grant No.12272035)the Beijing Nova Program(Grant No.202404846)the Key Program of National Natural Science Foundation of China(Grant No.92160203)。
文摘Centrifugal separation machinery,especially those with vertical rotor structures and ball joint constraints,face significant operational stability challenges due to shaft center position and vibration issues,as well as strong lateral crosscoupling characteristics from their complex support structure.To address these challenges,this study proposes a novel real-time control method for the center position of a centrifuge rotor.The method integrates a variable step-size least mean square notch filter(VSLNF),a tracking differentiator(TD),and an all-coefficient adaptive control(ACAC)based on a characteristic model.The method dynamically updates the characteristic model coefficients to adapt to system changes,achieving precise shaft center control.The VSLNF removes synchronous frequency vibrations,the TD handles complex dynamics,and the ACAC adapts to varying conditions.This approach is particularly suitable for centrifuges with complex support structures,differing from conventional magnetically levitated rotor systems.The numerical study establishes a finite element model of the centrifuge and designs an adaptive controller to adjust the rotor position in real-time.The combination of ACAC with VSLNF and TD allows for effective vibration control under both constant and variable speed conditions,significantly reducing high-speed vibrations after crossing critical speeds.Experimental results demonstrate that the method effectively controls rotor displacement and reduces vibrations,offering a novel solution for vibration control in industrial rotating machinery with significant engineering application value.
基金the National Social Science Fund of China(21CJL009,19ZDA047)the Nation nce Foundation of China(72271184,U1811462,71790594).
文摘Urban development thrives from technology inflows,which refers to the transfer of highvalue technology from various cities to local recipients.The asymmetry of technical information-rooted in the tacit knowledge inherent in technology-mandates that technology transfer is heavily dependent on interactions and communication among talented individuals.This study examines the effect of China's high-speed railway(HSR)on technology inflow,with an emphasis on talent interaction in the technology transfer process.The findings suggest that HSR mitigates cross-city commuting costs and facilitates face-to-face interactions between talent,thereby fostering an increase in technology inflows to various cities."Talent"use HSR to transfer knowledge to cities teeming with such talent resources.Concurrently,areas with robust intellectual property rights protection witness an upsurge in intercity technology transfer via HsR.This study elucidates the macro-mechanism of urban technology flow from the perspective of public transportation offering valuable insights for technology market infrastructure and services.
