Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understandin...Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.展开更多
In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measuremen...In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measurement system were performed.Two projectiles containing dummy HTPB propellant grains were successfully recovered after the flight tests with an ultrahigh acceleration overload value of 8100 g.The onboard-measured time-resolved axial displacement,contact stress and overload values were successfully obtained and analysed.Uniaxial compression tests of the dummy HTPB propellant used in the gunlaunched tests were carried out at low and intermediate strain rates to characterize the propellant's dynamic properties.A linear viscoelastic constitutive model was employed and applied in finite-element simulations of the projectile-launching process.During the launch process,the dummy propellant grain exhibited large deformation due to the high acceleration overload,possibly leading to friction between the motor case and propellant grain.The calculated contact stress showed good agreement with the experimental results,though discrepancies in the overall displacement of the dummy propellant grain were observed.The dynamic mechanical response process of the dummy propellant grain was analysed in detail.The results can be used to estimate the structural integrity of the analysed dummy propellant grain during the gun-launch process.展开更多
Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to comp...Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.展开更多
Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon emissions.Mineral storage is considered a reliable opt...Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon emissions.Mineral storage is considered a reliable option for long-term carbon storage.Basalt rich in alkaline earth elements facilitates rapid and permanent CO_(2) fixation as carbonates.However,the complex CO_(2)-fluid-basalt interaction poses challenges for assessing carbon storage potential.Under different reaction conditions,the carbonation products and carbonation rates vary.Carbon mineralization reactions also induce petrophysical and mechanical responses,which have potential risks for the long-term injectivity and the carbon storage safety in basalt reservoirs.In this paper,recent advances in carbon mineralization storage in basalt based on laboratory research are comprehensively reviewed.The assessment methods for carbon storage potential are introduced and the carbon trapping mechanisms are investigated with the identification of the controlling factors.Changes in pore structure,permeability and mechanical properties in both static reactions and reactive percolation experiments are also discussed.This study could provide insight into challenges as well as perspectives for future research.展开更多
The emergence of mechanically one-way materials presents an exciting opportunity for materials science and engineering. These substances exhibit unique nonreciprocal mechanical responses, enabling them to selectively ...The emergence of mechanically one-way materials presents an exciting opportunity for materials science and engineering. These substances exhibit unique nonreciprocal mechanical responses, enabling them to selectively channel mechanical energy and facilitate directed sound propagation, controlled mass transport, and concentration of mechanical energy amidst random motion. This article explores the fundamentals of mechanically one-way materials, their potential applications across various industries, and the economic and environmental considerations related to their production and use.展开更多
Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommo...Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommodation mechanism of the pre-rolled AZ31 magnesium alloy under high-speed impact loading were investigated.The twin and shear band are prevailing at low temperature,and the coexistence of twins and recrystallized grains is the dominant microstructure at medium temperature,while at high temperature,dynamic recrystallization(DRX)is almost complete.The increment of temperature reduces the critical condition difference between twinning and DRX,and the recrystallized temperature decreases with increasing strain rate.The mechanical response is related to the competition among the shear band strengthen,the twin strengthen and the fine grain strengthen and determined by the prevailing grain structure.The fine grain strengthen could compensate soften caused by the temperature increase and the reduction of twin and shear band.During high-speed deformation,different twin variants,introduced by pre-rolling,induce different deformation mechanism to accommodate plastic deformation and are in favor for non-basal slip.At low temperature,the high-speed deformation is achieved by twinning,dislocation slip and the following deformation shear band at different deformation stages.At high temperature,the high-speed deformation is realized by twinning and dislocation slip of early deformation stage,transition shear band of medium deformation stage and DRX of final deformation stage.展开更多
The compressive mechanical behavior of composite modified double base(CMDB)propellant was investigated across a wide scope of strain rates ranging from 10^(-3) s^(-1) to 4210 s^(-1) at room temperature,by applying a c...The compressive mechanical behavior of composite modified double base(CMDB)propellant was investigated across a wide scope of strain rates ranging from 10^(-3) s^(-1) to 4210 s^(-1) at room temperature,by applying a conventional universal testing machine and a split Hopkinson tension bar(SHPB),respectively.The derived stress-strain curves at different strain rates show a strong rate dependence,indicated that yield stress,ultimate stress and strain energy density of CMDB propellant all increase with strain rate by following a power law function,while the amplification of increase are different.The deformation and damage modes of CMDB propellant has changed from a typical ductile manner(cracking along the axial direction)to a brittle manner(maximum shear failure)with increasing of strain rate.Scanning electron microscopy(SEM)was employed to explore the microscopic failure characteristics of CMDB propellant.Under quasi-static loading,the nearly parallel micro-cracks propagating along the axial direction and the debonding of RDX particle without particle crushing can be observed.While under dynamic loading,the micro-crack is 45 angle to the axial direction,and multiple cracking modes of RDX particles appeared.Finally,the correlation between strain energy density and failure mechanisms of CMDB propellant was revealed by developing four characteristic failure modes.The findings of this study is very important to evaluate the structural integrity of CMDB propellant.展开更多
Realizing the accurate characterization for the dynamic damage process is a great challenge. Here we carry out testing simultaneously for dynamic monitoring and acoustic emission (AE) statistical analysis towards fi...Realizing the accurate characterization for the dynamic damage process is a great challenge. Here we carry out testing simultaneously for dynamic monitoring and acoustic emission (AE) statistical analysis towards fiber composites under mode-Ⅱ delamination damage. The load curve, AE relative energy, amplitude distribution, and amplitude spectrum are obtained and the delamination damage mechanism of the composites is investigated by the microscopic observation of a fractured specimen. The results show that the micro-damage accumulation around the crack tip region has a great effect on the evolutionary process of delamination. AE characteristics and amplitude spectrum represent the damage and the physical mechanism originating from the hierarchical microstructure. Our finding provides a novel aud feasible strategy to simultaneously evaluate the dynamic response and micro-damage mechanism for fiber composites.展开更多
Optical properties and responsive mechanisms of three newly synthesized fluorescent probes for hypochlorous acid (HOC1) are investigated by employing time-dependent density functional theory. The computational resul...Optical properties and responsive mechanisms of three newly synthesized fluorescent probes for hypochlorous acid (HOC1) are investigated by employing time-dependent density functional theory. The computational results show that the absorption and emission properties of these probes change obviously when they react with hypochlorous acid. It is found that the probe FHZ has the best performance according to the probing behavior. Moreover, the responsive mechanisms of the probes are studied by analyzing the distributions of molecular orbitals and charge transfer, which are shown as the photon- induced electron transfer (PET) for FHZ and the intramolecular charge transfer OCT) for the other two probes. Specially, solvent effect on optical properties of the probe FHZ before and after reaction is studied within the polarizable continuum model (PCM). It is shown that performance of the probe depends crucially on the solvent polarity. Our computational results agree well with the experimental measurement, and provide information for design of efficient two-photon fluorescent probes.展开更多
The wide distribution of saline-alkali land in China is a restrictive factor for the sustainable development of agriculture.Saline-alkaline soil inhibits the growth and development of crops,reducing its yield and qual...The wide distribution of saline-alkali land in China is a restrictive factor for the sustainable development of agriculture.Saline-alkaline soil inhibits the growth and development of crops,reducing its yield and quality.In this article,we summarized the germination status,physiological characteristics,response mechanisms and mitigation measures of different crops under saline-alkali stress in recent years,aiming to provide important reference for the study of saline-alkali tolerance mechanism in crops,cultivation of crop varieties tolerant to salts and alkalis and improvement of the utilization rate of saline-alkali land,and put forward suggestions for future development trend of saline-alkali land crops and mitigation measures.展开更多
On July 22, 2014, the second group of national human rights education and train- ing bases was announced,increasing the number of national bases from the previous three to a total of eight, which reflects the advancem...On July 22, 2014, the second group of national human rights education and train- ing bases was announced,increasing the number of national bases from the previous three to a total of eight, which reflects the advancement of human rights education and ~aining in China and has far-reaching significance.展开更多
Tunnels deeply buried have high crustal stress and are prone to large deformation disasters when encountering soft rock.The large deformation phenomenon during the construction process of the Maoxian Tunnel on the Che...Tunnels deeply buried have high crustal stress and are prone to large deformation disasters when encountering soft rock.The large deformation phenomenon during the construction process of the Maoxian Tunnel on the Chengdu-Lanzhou Railway is particularly evident.This article focuses on the large deformation problem of the No.1 inclined shaft of the Maoxian Tunnel,and uses on-site monitoring methods to explore the reasons for tunnel structure failure,and analyzes the mechanical behavior of the tunnel structure.By using numerical simulation methods,the effectiveness of the second-layer support in resisting creep loads in tunnels was studied,and the influence of the construction time of the secondlayer support on the mechanical properties of the tunnel was discussed.The results indicate that the first-layer support in the tunnel is a structural failure caused by asymmetric deformation caused by creep,while the second-layer support has a good effect on resisting creep loads.The research results can provide a technical reference for deformation control of squeezing tunnels.展开更多
This paper studies the Least Square Method to define high-speed railway(HSR) earthquake risk and solve the problem of its emergency response mechanism. Based on the construction of a monitoring system for HSR earthqua...This paper studies the Least Square Method to define high-speed railway(HSR) earthquake risk and solve the problem of its emergency response mechanism. Based on the construction of a monitoring system for HSR earthquake emergency response, the technical operational procedures for HSR seismic emergency response are proposed. The quantity, scale, and location of HSR earthquake emergency response mechanism are defined, and the corresponding emergency response system is built. In particular, the earthquake emergency response system can conduct real-time continuous dynamic monitoring of seismic activity along the railway. When earthquake occurs, the intensity of the ground motion is detected by the system. When the earthquake monitoring value reaches the earthquake alarm threshold, it will send an alarm signal to the dispatch center, and the emergency power supply will be forced to cut off. The earthquake emergency response system will continue to monitor the follow-up ground motion acceleration. The system provides the operation scheduling center with a basis for train operation control to resume operation after stopping. The monitoring result of the system reduces the disaster, and the secondary disaster is caused by the earthquake. This paper improves the HSR response mechanism in detecting earthquake disasters. The result improves the ability of HSR to deal with earthquake disasters, and reduces casualties and economic and property loss caused by earthquake disasters.展开更多
As a prerequisite and a guarantee for safe and efficient natural gas hydrates(NGHs)exploitation,it is imperative to effectively determine the mechanical properties of NGHs reservoirs and clarify the law of the change ...As a prerequisite and a guarantee for safe and efficient natural gas hydrates(NGHs)exploitation,it is imperative to effectively determine the mechanical properties of NGHs reservoirs and clarify the law of the change in the mechanical properties with the dissociation of NGHs during NGHs production tests by depressurization.Based on the development of Japan’s two offshore NGHs production tests in vertical wells,this study innovatively proposed a new subsea communication technology-accurate directional connection using a wet-mate connector.This helps to overcome the technical barrier to the communication between the upper and lower completion of offshore wells.Using this new communication technology,this study explored and designed a mechanical monitoring scheme for lower completion(sand screens).This scheme can be used to monitor the tensile stress and radial compressive stress of sand screens caused by NGHs reservoirs in real time,thus promoting the technical development for the rapid assessment and real-time feedback of the in-situ mechanical response of NGHs reservoirs during offshore NGHs production tests by depressurization.展开更多
The research of rock properties based on its inherent microscopic to mesoscopic porous structure has drawn great attention for its potential in predicting the macroscopic behavior of rocks.An accurate reconstruction o...The research of rock properties based on its inherent microscopic to mesoscopic porous structure has drawn great attention for its potential in predicting the macroscopic behavior of rocks.An accurate reconstruction of the threedimensional porous structure is a premise for the related studies of hydraulic and mechanical properties of rocks,such as the transport properties and mechanical responses under pressures.In this paper,we present a computer procedure for reconstructing the 3D porous structure of low-permeability sandstone.Two large-size 3D models are reconstructed based on the information of a reference model which is established from computed tomography(CT)images.A self-developed finite element method is applied to analyze the nonlinear mechanical behavior of the sandstone based on its reconstructed model and to compare the results with those based on the reference model.The good consistency of the obtained mechanical responses indicates the potential of using reconstruction models to predict the influences of porous structure on the mechanical properties of low-permeability sandstone.展开更多
The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation...The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.展开更多
Although insulin-like growth factor-I (IGF-I) and estrogen signaling pathways have been shown to be involved in mediating the bone anabolic response to mechanical loading, it is not known whether these two signaling...Although insulin-like growth factor-I (IGF-I) and estrogen signaling pathways have been shown to be involved in mediating the bone anabolic response to mechanical loading, it is not known whether these two signaling pathways crosstalk with each other in producing a skeletal response to mechanical loading. To test this, at 5 weeks of age, partial ovariectomy (pOVX) or a sham operation was performed on heterozygous IGF-I conditional knockout (H IGF-I KO) and control mice generated using a Cre-loxP approach. At 10 weeks of age, a 10 N axial load was applied on the right tibia of these mice for a period of 2 weeks and the left tibia was used as an internal non-non-loaded control. At the cortical site, partial estrogen loss reduced total volumetric bone mineral density (BMD) by 5% in control pOVX mice (P=0.05, one-way ANOVA), but not in the H IGF-I KO pOVX mice. At the trabecular site, bone volume/total volume (BV/TV) was reduced by 5%-6% in both control pOVX (P〈0.05) and H IGF-I KO pOVX (P=0.05) mice. Two weeks of mechanical loading caused a 7 %-8% and an 11%-13% (P〈0.05 vs. non-loaded bones) increase in cortical BMD and cortical thickness (Ct.Th), respectively, in the control sham, control pOVX and H IGF-I KO sham groups. By contrast, the magnitude of cortical BMD (4%, P=0.13) and Ct.Th (6%, P〈0.05) responses were reduced by 50% in the H IGF-I KO pOVX mice compared to the other three groups. The interaction between genotype and estrogen deficiency on the mechanical loading-induced cortical bone response was significant (P〈0.05) by two-way ANOVA. Two weeks of axial loading caused similar increases in trabecular BV/TV (13%-17%) and thickness (17%-23%) in all four groups of mice. In conclusion, partial loss of both estrogen and IGF-I significantly reduced cortical but not the trabecular bone response to mechanical loading, providing in vivo evidence of the above crosstalk in mediating the bone response to loading.展开更多
Quench and mechanical behaviors are critical issues in high temperature superconducting(HTS)coils.In this paper,the quench characteristics in the rare earth barium copper oxide(REBCO)pancake coil at 4.2K are analyzed,...Quench and mechanical behaviors are critical issues in high temperature superconducting(HTS)coils.In this paper,the quench characteristics in the rare earth barium copper oxide(REBCO)pancake coil at 4.2K are analyzed,and a two-dimensional(2D)axisymmetric electro-magneto-thermal model is presented.The effects of the constituent materials,background field,and coil size are analyzed.An elastoplastic mechanical model is used to study the corresponding mechanical responses during the quench propagation.The variations of the temperature and strain in superconducting layers are compared.The results indicate that the radial strain evolutions can reflect the transverse quench propagation and the tensile hoop and radial stresses in superconducting layers increase with the quench propagation.The possible damages are discussed with the consideration of the effects of the background field and coil size.It is concluded that the high background field significantly increases the maximum tensile hoop and radial stresses in quenching coils and local damage may be caused.展开更多
Nonlinear finite element simulation for mechanical response of surface mounted solder joint under different temperature cycling was carried out. Seven sets of parameters were used in order to evaluate the influence of...Nonlinear finite element simulation for mechanical response of surface mounted solder joint under different temperature cycling was carried out. Seven sets of parameters were used in order to evaluate the influence of temperature cycling profile parameters. The results show that temperature cycling history has significant effect on the stress response of the solder joint. Based on the concept of relative damage stress proposed by the authors, it is found that enough high temperature holding time is necessary for designing the temperature cycling profile in accelerated thermal fatigue test.展开更多
基金financial support from the China Postdoctora Science Foundation(project No.2021M690406)financial supports from the National Natural Science Foundation of China(project No.51708521,51778183)。
文摘Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.
文摘In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measurement system were performed.Two projectiles containing dummy HTPB propellant grains were successfully recovered after the flight tests with an ultrahigh acceleration overload value of 8100 g.The onboard-measured time-resolved axial displacement,contact stress and overload values were successfully obtained and analysed.Uniaxial compression tests of the dummy HTPB propellant used in the gunlaunched tests were carried out at low and intermediate strain rates to characterize the propellant's dynamic properties.A linear viscoelastic constitutive model was employed and applied in finite-element simulations of the projectile-launching process.During the launch process,the dummy propellant grain exhibited large deformation due to the high acceleration overload,possibly leading to friction between the motor case and propellant grain.The calculated contact stress showed good agreement with the experimental results,though discrepancies in the overall displacement of the dummy propellant grain were observed.The dynamic mechanical response process of the dummy propellant grain was analysed in detail.The results can be used to estimate the structural integrity of the analysed dummy propellant grain during the gun-launch process.
基金the financial support from the Natural Science Foundation of China (Nos.52179118,52209151 and 42307238)the Science and Technology Project of Jiangsu Provincial Department of Science and Technology-Carbon Emissions Peak and Carbon Neutrality Science and Technology Innovation Specia Fund Project (No.BK20220025)+3 种基金the Excellent Postdoctoral Program of Jiangsu Province (No.2023ZB602)the China Postdoctora Science Foundation (Nos.2023M733773 and 2023M733772)Xuzhou City Science and Technology Innovation Special Basic Research Plan (KC23045)State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,China University of Mining&Technology (No SKLGDUEK1916)。
文摘Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.
基金funding support from the National Key R&D Program of China(Grant No.2022YFE0115800)the Creative Groups of Natural Science Foundation of Hubei Province(Grant No.2021CFA030)Shanxi Provincial Key Research and Development Project(Grant No.202102090301009).
文摘Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon emissions.Mineral storage is considered a reliable option for long-term carbon storage.Basalt rich in alkaline earth elements facilitates rapid and permanent CO_(2) fixation as carbonates.However,the complex CO_(2)-fluid-basalt interaction poses challenges for assessing carbon storage potential.Under different reaction conditions,the carbonation products and carbonation rates vary.Carbon mineralization reactions also induce petrophysical and mechanical responses,which have potential risks for the long-term injectivity and the carbon storage safety in basalt reservoirs.In this paper,recent advances in carbon mineralization storage in basalt based on laboratory research are comprehensively reviewed.The assessment methods for carbon storage potential are introduced and the carbon trapping mechanisms are investigated with the identification of the controlling factors.Changes in pore structure,permeability and mechanical properties in both static reactions and reactive percolation experiments are also discussed.This study could provide insight into challenges as well as perspectives for future research.
文摘The emergence of mechanically one-way materials presents an exciting opportunity for materials science and engineering. These substances exhibit unique nonreciprocal mechanical responses, enabling them to selectively channel mechanical energy and facilitate directed sound propagation, controlled mass transport, and concentration of mechanical energy amidst random motion. This article explores the fundamentals of mechanically one-way materials, their potential applications across various industries, and the economic and environmental considerations related to their production and use.
基金supported by the National Natural Science Foundation of China(Nos.52071139,51905166,52075167)well as from the Natural Science Foundation of Hunan Province(2020JJ5198)the Open Platform Fund of Hunan Institute of Technology(KFA20014).
文摘Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommodation mechanism of the pre-rolled AZ31 magnesium alloy under high-speed impact loading were investigated.The twin and shear band are prevailing at low temperature,and the coexistence of twins and recrystallized grains is the dominant microstructure at medium temperature,while at high temperature,dynamic recrystallization(DRX)is almost complete.The increment of temperature reduces the critical condition difference between twinning and DRX,and the recrystallized temperature decreases with increasing strain rate.The mechanical response is related to the competition among the shear band strengthen,the twin strengthen and the fine grain strengthen and determined by the prevailing grain structure.The fine grain strengthen could compensate soften caused by the temperature increase and the reduction of twin and shear band.During high-speed deformation,different twin variants,introduced by pre-rolling,induce different deformation mechanism to accommodate plastic deformation and are in favor for non-basal slip.At low temperature,the high-speed deformation is achieved by twinning,dislocation slip and the following deformation shear band at different deformation stages.At high temperature,the high-speed deformation is realized by twinning and dislocation slip of early deformation stage,transition shear band of medium deformation stage and DRX of final deformation stage.
文摘The compressive mechanical behavior of composite modified double base(CMDB)propellant was investigated across a wide scope of strain rates ranging from 10^(-3) s^(-1) to 4210 s^(-1) at room temperature,by applying a conventional universal testing machine and a split Hopkinson tension bar(SHPB),respectively.The derived stress-strain curves at different strain rates show a strong rate dependence,indicated that yield stress,ultimate stress and strain energy density of CMDB propellant all increase with strain rate by following a power law function,while the amplification of increase are different.The deformation and damage modes of CMDB propellant has changed from a typical ductile manner(cracking along the axial direction)to a brittle manner(maximum shear failure)with increasing of strain rate.Scanning electron microscopy(SEM)was employed to explore the microscopic failure characteristics of CMDB propellant.Under quasi-static loading,the nearly parallel micro-cracks propagating along the axial direction and the debonding of RDX particle without particle crushing can be observed.While under dynamic loading,the micro-crack is 45 angle to the axial direction,and multiple cracking modes of RDX particles appeared.Finally,the correlation between strain energy density and failure mechanisms of CMDB propellant was revealed by developing four characteristic failure modes.The findings of this study is very important to evaluate the structural integrity of CMDB propellant.
基金Supported by the Natural Science Foundation of Hebei Province under Grant No E2012201084the National University Students’ Innovative Training Program under Grant No 201410075004
文摘Realizing the accurate characterization for the dynamic damage process is a great challenge. Here we carry out testing simultaneously for dynamic monitoring and acoustic emission (AE) statistical analysis towards fiber composites under mode-Ⅱ delamination damage. The load curve, AE relative energy, amplitude distribution, and amplitude spectrum are obtained and the delamination damage mechanism of the composites is investigated by the microscopic observation of a fractured specimen. The results show that the micro-damage accumulation around the crack tip region has a great effect on the evolutionary process of delamination. AE characteristics and amplitude spectrum represent the damage and the physical mechanism originating from the hierarchical microstructure. Our finding provides a novel aud feasible strategy to simultaneously evaluate the dynamic response and micro-damage mechanism for fiber composites.
基金supported by the National Natural Science Foundation of China(Grant Nos.11374195 and 11404193)the Taishan Scholar Program of Shandong Province,China
文摘Optical properties and responsive mechanisms of three newly synthesized fluorescent probes for hypochlorous acid (HOC1) are investigated by employing time-dependent density functional theory. The computational results show that the absorption and emission properties of these probes change obviously when they react with hypochlorous acid. It is found that the probe FHZ has the best performance according to the probing behavior. Moreover, the responsive mechanisms of the probes are studied by analyzing the distributions of molecular orbitals and charge transfer, which are shown as the photon- induced electron transfer (PET) for FHZ and the intramolecular charge transfer OCT) for the other two probes. Specially, solvent effect on optical properties of the probe FHZ before and after reaction is studied within the polarizable continuum model (PCM). It is shown that performance of the probe depends crucially on the solvent polarity. Our computational results agree well with the experimental measurement, and provide information for design of efficient two-photon fluorescent probes.
基金Tiemenguan Science and Technology Project of the Second Division of Xinjiang Production and Construction Corps(2019NYGG13)XPCC People’s Practical Livelihood Matter Project of"Improving the Level of Agricultural Science and Technology".
文摘The wide distribution of saline-alkali land in China is a restrictive factor for the sustainable development of agriculture.Saline-alkaline soil inhibits the growth and development of crops,reducing its yield and quality.In this article,we summarized the germination status,physiological characteristics,response mechanisms and mitigation measures of different crops under saline-alkali stress in recent years,aiming to provide important reference for the study of saline-alkali tolerance mechanism in crops,cultivation of crop varieties tolerant to salts and alkalis and improvement of the utilization rate of saline-alkali land,and put forward suggestions for future development trend of saline-alkali land crops and mitigation measures.
文摘On July 22, 2014, the second group of national human rights education and train- ing bases was announced,increasing the number of national bases from the previous three to a total of eight, which reflects the advancement of human rights education and ~aining in China and has far-reaching significance.
基金the National Natural Science Foundation of China(Grant No.51978041)。
文摘Tunnels deeply buried have high crustal stress and are prone to large deformation disasters when encountering soft rock.The large deformation phenomenon during the construction process of the Maoxian Tunnel on the Chengdu-Lanzhou Railway is particularly evident.This article focuses on the large deformation problem of the No.1 inclined shaft of the Maoxian Tunnel,and uses on-site monitoring methods to explore the reasons for tunnel structure failure,and analyzes the mechanical behavior of the tunnel structure.By using numerical simulation methods,the effectiveness of the second-layer support in resisting creep loads in tunnels was studied,and the influence of the construction time of the secondlayer support on the mechanical properties of the tunnel was discussed.The results indicate that the first-layer support in the tunnel is a structural failure caused by asymmetric deformation caused by creep,while the second-layer support has a good effect on resisting creep loads.The research results can provide a technical reference for deformation control of squeezing tunnels.
基金Sponsored by the National Natural Science Foundation of China (Grant No.51178157)the High-Level Project of the Top Six Talents of Jiangsu Province (Grant No.JXQC-021)the Key Science and Technology Program of Henan Province (Grant No.182102310004)。
文摘This paper studies the Least Square Method to define high-speed railway(HSR) earthquake risk and solve the problem of its emergency response mechanism. Based on the construction of a monitoring system for HSR earthquake emergency response, the technical operational procedures for HSR seismic emergency response are proposed. The quantity, scale, and location of HSR earthquake emergency response mechanism are defined, and the corresponding emergency response system is built. In particular, the earthquake emergency response system can conduct real-time continuous dynamic monitoring of seismic activity along the railway. When earthquake occurs, the intensity of the ground motion is detected by the system. When the earthquake monitoring value reaches the earthquake alarm threshold, it will send an alarm signal to the dispatch center, and the emergency power supply will be forced to cut off. The earthquake emergency response system will continue to monitor the follow-up ground motion acceleration. The system provides the operation scheduling center with a basis for train operation control to resume operation after stopping. The monitoring result of the system reduces the disaster, and the secondary disaster is caused by the earthquake. This paper improves the HSR response mechanism in detecting earthquake disasters. The result improves the ability of HSR to deal with earthquake disasters, and reduces casualties and economic and property loss caused by earthquake disasters.
基金supported jointly by the major projects of Basic and Applied Basic Research in Guangdong Province“Key Basic Theory Research for Natural Gas Hydrate Trial Production in Shenhu Pilot Test Area”(2020B0301030003)the project from Southern Marine Science&Engineering Guangdong Laboratory in Guangzhou City“Research on New Closed Circulation Drilling Technology without Riser”(GML2019ZD0501).
文摘As a prerequisite and a guarantee for safe and efficient natural gas hydrates(NGHs)exploitation,it is imperative to effectively determine the mechanical properties of NGHs reservoirs and clarify the law of the change in the mechanical properties with the dissociation of NGHs during NGHs production tests by depressurization.Based on the development of Japan’s two offshore NGHs production tests in vertical wells,this study innovatively proposed a new subsea communication technology-accurate directional connection using a wet-mate connector.This helps to overcome the technical barrier to the communication between the upper and lower completion of offshore wells.Using this new communication technology,this study explored and designed a mechanical monitoring scheme for lower completion(sand screens).This scheme can be used to monitor the tensile stress and radial compressive stress of sand screens caused by NGHs reservoirs in real time,thus promoting the technical development for the rapid assessment and real-time feedback of the in-situ mechanical response of NGHs reservoirs during offshore NGHs production tests by depressurization.
基金the financial supports from the National Natural Science Foundation for Distinguished Young Scholars of China(51125017)the National Natural Science Foundation of China(51374213)the National Basic Research Pro-gram of China(Grant 2010CB226804,2011CB201201).
文摘The research of rock properties based on its inherent microscopic to mesoscopic porous structure has drawn great attention for its potential in predicting the macroscopic behavior of rocks.An accurate reconstruction of the threedimensional porous structure is a premise for the related studies of hydraulic and mechanical properties of rocks,such as the transport properties and mechanical responses under pressures.In this paper,we present a computer procedure for reconstructing the 3D porous structure of low-permeability sandstone.Two large-size 3D models are reconstructed based on the information of a reference model which is established from computed tomography(CT)images.A self-developed finite element method is applied to analyze the nonlinear mechanical behavior of the sandstone based on its reconstructed model and to compare the results with those based on the reference model.The good consistency of the obtained mechanical responses indicates the potential of using reconstruction models to predict the influences of porous structure on the mechanical properties of low-permeability sandstone.
基金supported by the National Natural Science Foundation of China (# 81502345 to Qian Li and #81470717 to Yanheng Zhou)the International Science & Technology Cooperation Program of China (#2015DFB30040 to Yanheng Zhou)
文摘The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.
基金supported by the National Institutes of Health grant R01 AR48139 (to SM)National Institute of Arthritis and Musculoskeletal Skin Diseases R03 grant AR056827 (to CK)
文摘Although insulin-like growth factor-I (IGF-I) and estrogen signaling pathways have been shown to be involved in mediating the bone anabolic response to mechanical loading, it is not known whether these two signaling pathways crosstalk with each other in producing a skeletal response to mechanical loading. To test this, at 5 weeks of age, partial ovariectomy (pOVX) or a sham operation was performed on heterozygous IGF-I conditional knockout (H IGF-I KO) and control mice generated using a Cre-loxP approach. At 10 weeks of age, a 10 N axial load was applied on the right tibia of these mice for a period of 2 weeks and the left tibia was used as an internal non-non-loaded control. At the cortical site, partial estrogen loss reduced total volumetric bone mineral density (BMD) by 5% in control pOVX mice (P=0.05, one-way ANOVA), but not in the H IGF-I KO pOVX mice. At the trabecular site, bone volume/total volume (BV/TV) was reduced by 5%-6% in both control pOVX (P〈0.05) and H IGF-I KO pOVX (P=0.05) mice. Two weeks of mechanical loading caused a 7 %-8% and an 11%-13% (P〈0.05 vs. non-loaded bones) increase in cortical BMD and cortical thickness (Ct.Th), respectively, in the control sham, control pOVX and H IGF-I KO sham groups. By contrast, the magnitude of cortical BMD (4%, P=0.13) and Ct.Th (6%, P〈0.05) responses were reduced by 50% in the H IGF-I KO pOVX mice compared to the other three groups. The interaction between genotype and estrogen deficiency on the mechanical loading-induced cortical bone response was significant (P〈0.05) by two-way ANOVA. Two weeks of axial loading caused similar increases in trabecular BV/TV (13%-17%) and thickness (17%-23%) in all four groups of mice. In conclusion, partial loss of both estrogen and IGF-I significantly reduced cortical but not the trabecular bone response to mechanical loading, providing in vivo evidence of the above crosstalk in mediating the bone response to loading.
基金the National Natural Science Foundation of China(Nos.11872195,11472120,and 11802036)the 111 Project(No.B14044)。
文摘Quench and mechanical behaviors are critical issues in high temperature superconducting(HTS)coils.In this paper,the quench characteristics in the rare earth barium copper oxide(REBCO)pancake coil at 4.2K are analyzed,and a two-dimensional(2D)axisymmetric electro-magneto-thermal model is presented.The effects of the constituent materials,background field,and coil size are analyzed.An elastoplastic mechanical model is used to study the corresponding mechanical responses during the quench propagation.The variations of the temperature and strain in superconducting layers are compared.The results indicate that the radial strain evolutions can reflect the transverse quench propagation and the tensile hoop and radial stresses in superconducting layers increase with the quench propagation.The possible damages are discussed with the consideration of the effects of the background field and coil size.It is concluded that the high background field significantly increases the maximum tensile hoop and radial stresses in quenching coils and local damage may be caused.
文摘Nonlinear finite element simulation for mechanical response of surface mounted solder joint under different temperature cycling was carried out. Seven sets of parameters were used in order to evaluate the influence of temperature cycling profile parameters. The results show that temperature cycling history has significant effect on the stress response of the solder joint. Based on the concept of relative damage stress proposed by the authors, it is found that enough high temperature holding time is necessary for designing the temperature cycling profile in accelerated thermal fatigue test.