Plantshave evolvedvariousmechanismsto interact withmicroorganisms,which help them acquire nutrients from the soil and enhance their tolerance to environmental stresses.One of the most widespread mutualistic interactio...Plantshave evolvedvariousmechanismsto interact withmicroorganisms,which help them acquire nutrients from the soil and enhance their tolerance to environmental stresses.One of the most widespread mutualistic interactions is arbuscular mycorrhizal(AM)symbiosis,which is formed by 80%-90%of terrestrial plants in association with AM fungi.In AM symbiosis,plants acquire mineral nutrients from the fungi in exchange for fatty acids and sugars that are produced during photosynthesis(Jiang et al.,2017).展开更多
Laser-welded Ti-6Al-4 V is prone to severe residual stresses,microstructural variation,and structural de-fects which are known detrimental to the mechanical properties of weld joints.Residual stress removal is typical...Laser-welded Ti-6Al-4 V is prone to severe residual stresses,microstructural variation,and structural de-fects which are known detrimental to the mechanical properties of weld joints.Residual stress removal is typically applied to weld joints for engineering purposes via heat treatment,in order to avoid prema-ture failure and performance degradation.In the present work,we found that proper welding residual stresses in laser-welded Ti-6Al-4 V sheets can maintain better ductility during uniaxial tension,as op-posed to the stress-relieved counterparts.A detailed experimental investigation has been performed on the deformation behaviours of Ti-6Al-4 V butt welds,including residual stress distribution characteriza-tions by focused ion beam ring-coring coupled with digital image correlation(FIB-DIC),X-ray comput-erized tomography(CT)for internal voids,and in-situ DIC analysis of the subregional strain evolutions.It was found that the pores preferentially distributed near the fusion zone(FZ)boundary,where the compressive residual stress was up to-330 MPa.The removal of residual stress resulted in a changed failure initiation site from the base material to the FZ boundary,the former with ductile and the latter with brittle fracture characteristics under tensile deformation.The combined effects of residual stresses,microstructures,and internal pores on the mechanical responses are discussed in detail.This work high-lights the importance of inevitable residual stress and pores in laser weld pieces,leading to key insights for post-welding treatment and service performance evaluations.展开更多
Currently,there is a lack of in-situ or model test results for cone penetration tests(CPTs)conducted in deep,dense sand layers under high overburden stresses,restricting the development of empirical relationships betw...Currently,there is a lack of in-situ or model test results for cone penetration tests(CPTs)conducted in deep,dense sand layers under high overburden stresses,restricting the development of empirical relationships between CPT results and the characteristics of such deep,dense sand layers.This study addresses this gap by proposing an empirical relationship to predict the relative density of dense silica sand based on stress level and cone tip resistance.The relationship was developed through CPTs performed in a calibration chamber using dense sand specimens(with relative densities of 74%-91%)subjected to high stresses(under overburden stresses of 0.5-2.0 MPa)and numerical simulations employing the large deformation finite element method.The Arbitrary Lagrangian Eulerian method was used to regularly regenerate the mesh to prevent soil element distortion around the cone tip.Additionally,the modified Mohr-Coulomb model was integrated to capture the stress-strain behavior of dense silica sand under high stresses.A reasonable agreement was achieved between the numerical and experimental penetration profiles,which verifies the reliability of the numerical model.A sufficient number of parametric analyses were carried out,and then an empirical equation was proposed to establish the relationship between the relative density of dense sand,stress level and cone resistance.The empirical equation provides predictions with acceptable accuracy,as the discrepancies between the predicted and measured relative density values fall within±30%.展开更多
A steady rise in the overall population is creating an overburden on crops due to their global demand.On the other hand,given the current climate change and population growth,agricultural practices established during ...A steady rise in the overall population is creating an overburden on crops due to their global demand.On the other hand,given the current climate change and population growth,agricultural practices established during the Green Revolution are no longer viable.Consequently,innovative practices are the prerequisite of the time struggle with the rising global food demand.The potential of nanotechnology to reduce the phytotoxic effects of these ecological restrictions has shown significant promise.Nanoparticles(NPs)typically enhance plant resilience to stressors by fortifying the physical barrier,optimizing photosynthesis,stimulating enzymatic activity for defense,elevating the concentration of stress-resistant compounds,and activating the expression of genes associated with defense mechanisms.In this review,we thoroughly cover the uptake and translocations of NPs crops and their potential valuable functions in enhancing plant growth and development at different growth stages.Additionally,we addressed how NPs improve plant resistance to biotic and abiotic stress.Generally,this review presents a thorough understanding of the significance of NPs in plants and their prospective value for plant antioxidant and crop development.展开更多
Plants are continuously exposed to abiotic and biotic stresses that threaten their growth,reproduction,and survival.Adaptation to these stresses requires complex regulatory networks that coordinate physiological,molec...Plants are continuously exposed to abiotic and biotic stresses that threaten their growth,reproduction,and survival.Adaptation to these stresses requires complex regulatory networks that coordinate physiological,molecular,and ecological responses.However,such adaptation often incurs significant costs,including reduced growth,yield penalties,and altered ecological interactions.This review systematically synthesizes recent advances published between 2018 and 2025,following PRISMA criteria,on plant responses to abiotic and biotic stressors,with an emphasis on the trade-offs between adaptation and productivity.It also highlights major discrepancies in the literature and discusses strategies for enhancing plant stress tolerance in agriculture.By integrating findings from genomics,transcriptomics,proteomics,and metabolomics,the review categorizes both mechanistic insights and ecological consequences.The findings underscore the need for multi-stress,systems-level,field-based research that connects molecular processes to ecological and agricultural outcomes.Accordingly,critical gaps are identified—particularly the scarcity of multi-stress and field-based studies—and future directions that integrate omics approaches,systems biology,and eco-physiological frameworks are proposed.Understanding the costs of adaptation is essential not only for breeding resilient,high-yielding crops but also for ensuring their successful incorporation into sustainable agricultural practices under changing climate conditions.展开更多
In the past decades,residual stresses have attracted wide attention due to their significant influences on material’s strength,fatigue life,and dimensional stability.Various residual stress measurement methods have b...In the past decades,residual stresses have attracted wide attention due to their significant influences on material’s strength,fatigue life,and dimensional stability.Various residual stress measurement methods have been developed such as X-ray diffraction,neutron diffraction,crack compliance,and hole drilling.These methods may suffer from different disadvantages including radiation,high cost,destructive,unportable,etc.In this work,an in situ residual stress measurement method was proposed based on instrumented indentation using a piezoelectric bimorph cantilever.A Vickers’indenter was fabricated onto the free end of the cantilever for pressing into the sample and a strain gauge was bonded on the cantilever to monitor the indentation load.During testing,the contact area was extracted by tracking the cantilever’s contact resonance frequency based on the electromechanical impendence method.Different from traditional indentation-based methods that use a single hardness value to compute the residual stress,here the indentation force-contact area(F-S)curves with and without residual stresses were measured to derive the residual stress based on an empirical model.Experiments were then conducted on a specially designed CrMnCu specimen with different applied stresses.Results show that the measured residual stress values agreed well with the applied stresses monitored by a strain gauge.The proposed residual stress measurement method holds great promise for in situ residual stress estimation due to its portable apparatus,simple operation procedure and insensitiveness to testing environment.展开更多
The study aimed to address the issue of elevated residual stress levels in dissimilar girth welds of cast steel joints.To achieve this,the hybrid welding technology,which yields high welding speeds while simultaneousl...The study aimed to address the issue of elevated residual stress levels in dissimilar girth welds of cast steel joints.To achieve this,the hybrid welding technology,which yields high welding speeds while simultaneously reducing residual stresses,has been introduced.This study utilizes a numerical simulation method to investigate the temperature and residual stress field in the hybrid welding of G20Mn5 casting-Q355 low-alloy steel welded pipe.A com-parison of the findings of this study with those of other welding processes revealed the technological advantages of hybrid welding.The research outcomes show that due to geometric discontinuities and material differences,the temperature field of the joint exhibits uneven distribution characteristics,and the peak temperatures on the Q355 steel side exceeds those on the G20Mn5 steel side.An evident stress gra-dient is present in the residual stress field of the joint post-welding,with peak stress located at the weld root on the Q355 steel.Compared with arc welding,the hybrid welding leads to decreased residual stresses and deformation,with high stress outside the heat-affected zone diminishing rapidly.Furthermore,it significantly improves the welding efficiency.This study elucidates the distribution and underlying causes of thermal and residual stress fields in dissimilar girth welds.This serves as a foundation for the application of hybrid welding technology in welded cast steel joints.展开更多
Phosphorus(P)is an essential macronutrient required for plant growth,development,and resilience to environmental stresses.Its availability in soil and homeostasis within plants are strongly influenced by environmental...Phosphorus(P)is an essential macronutrient required for plant growth,development,and resilience to environmental stresses.Its availability in soil and homeostasis within plants are strongly influenced by environmental conditions,with unfavorable environments and soil factors disrupting phosphate availability,absorption,transport,and utilization.Optimizing phosphate supply can alleviate the detrimental impacts of abiotic stresses,thereby supporting growth and improving stress tolerance.Recent studies reveal that abiotic stresses modulate phosphate signaling pathways and alter the expression of phosphate-responsive genes,often affecting key regulators of P homeostasis.Strategic manipulation of phosphate transporters and their regulatory pathways offers a promising approach to enhance plant adaptation to challenging environments.This review highlights current advances in understanding the molecular mechanisms that coordinate P-responsive gene expression and homeostasis pathways under fluctuating P availability and stress conditions.It emphasizes the critical role of P nutrition in enhancing plant stress tolerance through antioxidant activation,osmolyte accumulation,membrane stabilization,and metal-phosphate complex formation.An in-depth mechanistic understanding of P-stress interactions will inform the development of P-efficient and stress-resistant crop varieties and guide more sustainable P fertilizer management in agriculture.展开更多
Wear is a prevalent issue across various industries. Spherical fused tungsten carbide (sFTC) reinforced nickel-aluminum bronze (NAB) matrix composite surface deposits have shown remarkable potential in mitigating wear...Wear is a prevalent issue across various industries. Spherical fused tungsten carbide (sFTC) reinforced nickel-aluminum bronze (NAB) matrix composite surface deposits have shown remarkable potential in mitigating wear by approximately 80%. However, the performance of these sFTC/NAB composite surface deposits is determined by their residual stress state, and the precise macroscopic and microscopic residual stresses within these composites have yet to be clearly established. To address this gap, we employed neutron diffraction to measure the residual stresses in the sFTC/NAB composite surface deposits and re-melted NAB samples produced via laser melt injection. Significant residual stresses were determined. The maximum tensile macro residual stress appears approximately 1-1.5 mm below the composite layer. Residual stresses accumulate with an increasing number of laser process tracks. The maximum tensile macro residual stress in the three-track samples reaches about 350 MPa. Preheating the base plate significantly reduces the levels of macroscopic residual stress. The WC phase displayed significant compressive thermal misfit residual stress magnitude, while the Cu matrix exhibited tensile thermal misfit residual stress. Preheating the base plate does not reduce microscopic thermal misfit residual stress levels. In addition, a finite element model was built to investigate temperature and residual stresses in the re-melted NAB samples. The predicted temperature history and residual stress agree with the experimental results.展开更多
Glutathione S-transferases (GSTs) represent a large and diverse enzyme family ubiquitously distributed across the plant kingdom. These proteins catalyze the conjugation of glutathione (GSH) with electrophilic substrat...Glutathione S-transferases (GSTs) represent a large and diverse enzyme family ubiquitously distributed across the plant kingdom. These proteins catalyze the conjugation of glutathione (GSH) with electrophilic substrates in response to various stress conditions. Beyond their role in stress adaptation, certain GSTs are integral regulators of plant growth and development, contributing to a range of physiological processes. Most GST proteins exhibit dual enzymatic activities, functioning as both transferases and peroxidases, which enables their involvement in diverse cellular processes, including detoxification and stress responses. Recent advancements, particularly in X-ray crystallography, have enabled detailed structural analysis of GST proteins, significantly enhancing our understanding of their biological functions. This review offers a comprehensive overview of the classification and structural characteristics of GSTs in plants. It also highlights recent findings on their roles in plant growth and development, cell signaling, catalytic transport, and stress tolerance. Furthermore, key scientific challenges related to GSTs are discussed, focusing on their potential applications in agriculture. These insights aim to facilitate the screening of functional GST genes and support molecular breeding efforts across diverse crop species.展开更多
Landslides frequently occurred in Jurassic red strata in the Three Gorges Reservoir(TGR)region in China.The Jurassic strata consist of low mechanical strength and poor permeability of weak silty mudstone layer,which m...Landslides frequently occurred in Jurassic red strata in the Three Gorges Reservoir(TGR)region in China.The Jurassic strata consist of low mechanical strength and poor permeability of weak silty mudstone layer,which may cause slope instability during rainfall.In order to understand the strength behavior of Jurassic silty mudstone shear zone,the so-called Shizibao landslide located in Guojiaba Town,Zigui County,Three Gorges Reservoir(TGR)in China is selected as a case study.The shear strength of the silty mudstone shear zone is strongly influenced by both the water content and the normal stress.Therefore,a series of drained ring shear tests were carried out by varying the water contents(7%,12%,17%,and 20%,respectively)and normal stresses(200,300,400,and 500 kPa,respectively).The result revealed that the residual friction coefficient and residual friction angle were power function relationships with water content and normal stress.The peak cohesion of the silty mudstone slip zone increased with water content to a certain limit,above which the cohesion decreased.In contrast,the residual cohesion showed the opposite trend,indicating the cohesion recovery above a certain limit of water content.However,both the peak and residual friction angle of the silty mudstone slip zone were observed to decrease steadily with increased water content.Furthermore,the macroscopic morphological features of the shear surface showed that the sliding failure was developed under high normal stress at low water content,while discontinuous sliding surface and soil extrusion were occurred when the water content increased to a saturated degree.The localized liquefaction developed by excess pore water pressure reduced the frictional force within the shear zone.Finally,the combined effects of the slope excavation and precipitation ultimately lead to the failure of the silty mudstone slope;however,continuous rainfall is the main factor triggering sliding.展开更多
Rolling path squeezes and rolling residual stresses of large diameter circular saw body for wood, generated by rolling pressure from 10 up to 120 bar were examined. X-ray diffraction, Barkhausen noise (BN) and Full Wi...Rolling path squeezes and rolling residual stresses of large diameter circular saw body for wood, generated by rolling pressure from 10 up to 120 bar were examined. X-ray diffraction, Barkhausen noise (BN) and Full Width of the peak at a Half Maximum (FWHM) (o) methods for evaluation of residual stresses were used. Dependencies of a tangential rolling residual stresses inside rolling paths upon rolling pressure p (bar) and rolling area A (mm2) were evaluated. The rolling pressure, as large as 60 bar, resulting in the rolling squeeze as high as 0.04 mm2, and, tangential residual compression stresses inside a rolling path, as large as ?TI = ?822 MPa, was considered to be the largest for the practical application.展开更多
In order to examine the effects of the decrease of future precipitation on the eco-physiological characteristics of sea buckthorn (Hippophae rhamnoides Linn.) in Huangfuchuan Watershed in Nei Mongol, a water gradient ...In order to examine the effects of the decrease of future precipitation on the eco-physiological characteristics of sea buckthorn (Hippophae rhamnoides Linn.) in Huangfuchuan Watershed in Nei Mongol, a water gradient experiment was conducted based on the four specially designed water supply levels, including normal precipitation, slight drought, drought and extreme drought. Results of ANOVE showed that different water gradients had a significant effect on (1) microhabitat factors, such as soil water content and soil temperature; (2) gas exchange, such as net photosynthetic rate, stomatal conductance and transpiration rate; (3) resource use efficiency; and (4) leaf water potential. Water use efficiency of H rhamnoides could increase under moderate water stress, i.e. drought condition, while its net photosynthetic rate and transpiration rate decreased. All kinds of eco-physiological characteristics proved H. rhamnoides seedlings under all water supplies were affected by water stress more or less and that mechanism of intrinsic physiological regulation in seedlings under the extreme drought conditions had the appearance of turbulence to a certain extent. Therefore, H rhamnoides seedlings in Huangfuchuan Watershed could not acclimate to extreme drought conditions.展开更多
The effect of silicon doping on the residual stress of CVD diamond films is examined using both X-ray diffraction (XRD) analysis and Raman spectroscopy measurements. The examined Si-doped diamond films are deposited o...The effect of silicon doping on the residual stress of CVD diamond films is examined using both X-ray diffraction (XRD) analysis and Raman spectroscopy measurements. The examined Si-doped diamond films are deposited on WC-Co substrates in a home-made bias-enhanced HFCVD apparatus. Ethyl silicate (Si(OC2H5)4) is dissolved in acetone to obtain various Si/C mole ratio ranging from 0.1% to 1.4% in the reaction gas. Characterizations with SEM and XRD indicate increasing silicon concentration may result in grain size decreasing and diamond [110] texture becoming dominant. The residual stress values of as-deposited Si-doped diamond films are evaluated by both sin2ψ method, which measures the (220) diamond Bragg diffraction peaks using XRD, with ψ-values ranging from 0° to 45°, and Raman spectroscopy, which detects the diamond Raman peak shift from the natural diamond line at 1332 cm-1. The residual stress evolution on the silicon doping level estimated from the above two methods presents rather good agreements, exhibiting that all deposited Si-doped diamond films present compressive stress and the sample with Si/C mole ratio of 0.1% possesses the largest residual stress of ~1.75 GPa (Raman) or ~2.3 GPa (XRD). As the silicon doping level is up further, the residual stress reduces to a relative stable value around 1.3 GPa.展开更多
The finite-element method has been used to study the thermal stress distribution in large-sized sapphire crystals grown with the sapphire growth technique with micro-pulling and shoulder-expanding at cooled center （S...The finite-element method has been used to study the thermal stress distribution in large-sized sapphire crystals grown with the sapphire growth technique with micro-pulling and shoulder-expanding at cooled center （SAPMAC） method. A critical defect model has been established to explain the growth and propagation of cracks during the sapphire growing process. It is demonstrated that the stress field depends on the growth rate, the ambient temperature and the crystallizing direction. High stresses always exist near the growth interfaces, at the shoulder-expanding locations, the tailing locations and the sites where the diameters undergo sharp changes. The maximum stresses always occur at the interface of seeds and crystals. Cracks often form in the critical defect region and spread in the m-planes and a-planes under applied tensile stresses during crystal growth. The experimental results have verified that with the improved system of crystal growth and well-controlled techniques, the large-sized sapphire crystals of high quality can be grown due to absence of cracks.展开更多
Seven reinforced concrete （RC） beams with epoxy-bonded glass fiber reinforced plastic （GFRP） sheets and two control RC beams were experimentally tested to investigate the bond behavior of the interfaces between RC...Seven reinforced concrete （RC） beams with epoxy-bonded glass fiber reinforced plastic （GFRP） sheets and two control RC beams were experimentally tested to investigate the bond behavior of the interfaces between RC beams and GFRP sheets. The variable parameters considered in test beams are the layers of GFRP sheets, the bond lengths and the reinforcement ratios. The results indicate that the flexural strength of the repaired beams is increased, but the ultimate load of beams with GFRP sheets debonding failure is reduced relatively. The bond length is the main factor that results in bonding failure of the strengthened beams. An experimental method of interfacial shear stress is proposed to analyze the distribution of shear stress according to experimental results. The analytical method of shear and normal stresses and a simple equation are proposed to predict the peeling loads. The proposed model is applied to experimental beams. The analytical results show a good agreement with the experimental results.展开更多
The stress aging behavior of Al-Cu alloy under various applied stresses, i.e., elastic stress, yield stress and plasticdeformation stress, was investigated using single crystals. The resulting microstructures and the ...The stress aging behavior of Al-Cu alloy under various applied stresses, i.e., elastic stress, yield stress and plasticdeformation stress, was investigated using single crystals. The resulting microstructures and the yield strength were examined bytransmission electron microscopy （TEM） and compression tests, respectively. The results indicate that an elastic stress of 15 MPa ishigh enough to influence the precipitation distribution of θ′ during aging at 180℃. The applied stress loading along [116]Aldirection results in increased number density of θ′ on （001）Al habit planes. This result becomes more significant with increasingapplied stress and leads to lower yield strength of Al-Cu single crystals during aging. Moreover, the generation of the preferentialorientation of θ′ was discussed by the effect of the dislocation induced by applied stress as well as the role of the misfit between theθ′-precipitate and Al matrix. The results are in agreement with the effect of the latter one.展开更多
Several automotive parts such as door panels have been manufactured by using load-adapted blanks for crash optimization and weight minimization. Recently, Tailor Rolled Blanks (TRB) has been introduced to remove the d...Several automotive parts such as door panels have been manufactured by using load-adapted blanks for crash optimization and weight minimization. Recently, Tailor Rolled Blanks (TRB) has been introduced to remove the disadvantages of a welding process which was used in joining panel components. TRB offers better structural design capabilities due to the seamless transitions on the panels with different thicknesses. In spite of the advantages of the process, TRB leaves internal stresses in the panel. This residual stresses lower the formability of Tailor Rolled Blanked (TRBed) parts and cause cracks near severe curvature during subsequent forming processes. In this research, the residual stresses of TRBed Al5J32-T4 sheets were studied by X-ray stress analysis, and also microstructure was observed along the rolling direction. In addition, heat treatment was done after TRB process in order to compare the residual stresses to that of the TRBed sheets before the heat treatment.展开更多
Spur gears are widely used in the power transmission mechanism of several machines.Due to the transmitted torque,spur gears experience high stresses which could cause gear tooth failure by surface pitting or root frac...Spur gears are widely used in the power transmission mechanism of several machines.Due to the transmitted torque,spur gears experience high stresses which could cause gear tooth failure by surface pitting or root fracture.Tip relief and other gear profile modification have been considered for reducing the induced stresses in the gear tooth.In this work,the influence of tip relief on stresses on a pair of identical spur gear was analyzed using commercial FEA software ANSYS,and formulae for estimating contact and bending stresses were derived.Three cases of gear sets were analyzed;a non-modified pair and another two sets with linear and parabolic tip relief profiles.The non-modified gear set frictionless contact stress was validated against the calculated AGMA pitting resistance,Hertzian contact stress and a reported contact stress value in the literature.The four methods agreed well with each other.Similarly,bending stress was also compared with the AGMA bending strength and Lewis bending stress for validation.Then,friction coefficient was varied from 0.0 to 0.3 with increment of 0.1.The gear contact stress increased up to 11%relative to the frictionless case,whereas bending stress decreased by 6%.Linear tip relief modification was carried out for increasing normalised tip relief values of 0.25 to 1.0 with increment of 0.25.The gear frictionless contact and bending stresses decreased by a maximum of 4%and 2%,respectively.Frictional contact stress increased by up to 7.1%and the bending stress is almost identical with the frictionless case.Parabolic tip relief was also carried out with similar normalised tip relief values.Frictionless contact stress decreased by 5%while frictional contact stress increased by up to 11.5%and the bending stress is also almost identical with the frictionless case.Finally,four formulae were introduced for estimating the contact and bending stresses for a tip modified spur gear.展开更多
On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating botto...On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating bottom shear stresses （BSS） and their effect on a sediment resuspension. Swell induced BSS have been found to be the most important part of the BSS. In this study, the correlation coefficient between a wavecurrent shear stress and SSC is 0.86, and that between current shear stresses and SSC is only 0.40. The peaks of the SSC are consistent with the height and the BSS of the swell. The swell is the main mechanism for the sediment re-suspension, and the tidal current effect on sediment re-suspension is small. The peaks of the SSC are centered on the high tidal level, and the flood tide enhances the wave shear stresses and the SSC near the bottom. The critical shear stress for sediment re-suspension at the observation station is between 0.20 and 0.30 N/m2. Tidal currents are too weak to stir up the bottom sediment into the flow, but a WCI （wave-current interaction） is strong enough to re-suspend the coarse sediment.展开更多
基金supported by the National Key R&D Program of China(2022YFF1001800)the National Natural Science Foundation of China(32088102)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0630103).
文摘Plantshave evolvedvariousmechanismsto interact withmicroorganisms,which help them acquire nutrients from the soil and enhance their tolerance to environmental stresses.One of the most widespread mutualistic interactions is arbuscular mycorrhizal(AM)symbiosis,which is formed by 80%-90%of terrestrial plants in association with AM fungi.In AM symbiosis,plants acquire mineral nutrients from the fungi in exchange for fatty acids and sugars that are produced during photosynthesis(Jiang et al.,2017).
基金supported by the National Key Re-search&Development Plan of China(No.2020YFA0405900)the Major Research Plan of the National Natural Science Foundation of China(No.92263201)Y.P.Xia would like to thank the support by the Jiangsu Funding Program for Excellent Postdoctoral Talent.All authors thank the Advanced Material Research Institute of Jiangsu Industrial Technology Research Institute(JITRI,Suzhou,China)for the experimental support.
文摘Laser-welded Ti-6Al-4 V is prone to severe residual stresses,microstructural variation,and structural de-fects which are known detrimental to the mechanical properties of weld joints.Residual stress removal is typically applied to weld joints for engineering purposes via heat treatment,in order to avoid prema-ture failure and performance degradation.In the present work,we found that proper welding residual stresses in laser-welded Ti-6Al-4 V sheets can maintain better ductility during uniaxial tension,as op-posed to the stress-relieved counterparts.A detailed experimental investigation has been performed on the deformation behaviours of Ti-6Al-4 V butt welds,including residual stress distribution characteriza-tions by focused ion beam ring-coring coupled with digital image correlation(FIB-DIC),X-ray comput-erized tomography(CT)for internal voids,and in-situ DIC analysis of the subregional strain evolutions.It was found that the pores preferentially distributed near the fusion zone(FZ)boundary,where the compressive residual stress was up to-330 MPa.The removal of residual stress resulted in a changed failure initiation site from the base material to the FZ boundary,the former with ductile and the latter with brittle fracture characteristics under tensile deformation.The combined effects of residual stresses,microstructures,and internal pores on the mechanical responses are discussed in detail.This work high-lights the importance of inevitable residual stress and pores in laser weld pieces,leading to key insights for post-welding treatment and service performance evaluations.
基金National Natural Science Foundation of China(Nos.42025702,52394251)。
文摘Currently,there is a lack of in-situ or model test results for cone penetration tests(CPTs)conducted in deep,dense sand layers under high overburden stresses,restricting the development of empirical relationships between CPT results and the characteristics of such deep,dense sand layers.This study addresses this gap by proposing an empirical relationship to predict the relative density of dense silica sand based on stress level and cone tip resistance.The relationship was developed through CPTs performed in a calibration chamber using dense sand specimens(with relative densities of 74%-91%)subjected to high stresses(under overburden stresses of 0.5-2.0 MPa)and numerical simulations employing the large deformation finite element method.The Arbitrary Lagrangian Eulerian method was used to regularly regenerate the mesh to prevent soil element distortion around the cone tip.Additionally,the modified Mohr-Coulomb model was integrated to capture the stress-strain behavior of dense silica sand under high stresses.A reasonable agreement was achieved between the numerical and experimental penetration profiles,which verifies the reliability of the numerical model.A sufficient number of parametric analyses were carried out,and then an empirical equation was proposed to establish the relationship between the relative density of dense sand,stress level and cone resistance.The empirical equation provides predictions with acceptable accuracy,as the discrepancies between the predicted and measured relative density values fall within±30%.
基金The authors extend their gratitude to the Deanship of Scientific Research(DSR),King Faisal University,Saudi Arabia,for funding the publication of this work(Project number:KFU250560).
文摘A steady rise in the overall population is creating an overburden on crops due to their global demand.On the other hand,given the current climate change and population growth,agricultural practices established during the Green Revolution are no longer viable.Consequently,innovative practices are the prerequisite of the time struggle with the rising global food demand.The potential of nanotechnology to reduce the phytotoxic effects of these ecological restrictions has shown significant promise.Nanoparticles(NPs)typically enhance plant resilience to stressors by fortifying the physical barrier,optimizing photosynthesis,stimulating enzymatic activity for defense,elevating the concentration of stress-resistant compounds,and activating the expression of genes associated with defense mechanisms.In this review,we thoroughly cover the uptake and translocations of NPs crops and their potential valuable functions in enhancing plant growth and development at different growth stages.Additionally,we addressed how NPs improve plant resistance to biotic and abiotic stress.Generally,this review presents a thorough understanding of the significance of NPs in plants and their prospective value for plant antioxidant and crop development.
文摘Plants are continuously exposed to abiotic and biotic stresses that threaten their growth,reproduction,and survival.Adaptation to these stresses requires complex regulatory networks that coordinate physiological,molecular,and ecological responses.However,such adaptation often incurs significant costs,including reduced growth,yield penalties,and altered ecological interactions.This review systematically synthesizes recent advances published between 2018 and 2025,following PRISMA criteria,on plant responses to abiotic and biotic stressors,with an emphasis on the trade-offs between adaptation and productivity.It also highlights major discrepancies in the literature and discusses strategies for enhancing plant stress tolerance in agriculture.By integrating findings from genomics,transcriptomics,proteomics,and metabolomics,the review categorizes both mechanistic insights and ecological consequences.The findings underscore the need for multi-stress,systems-level,field-based research that connects molecular processes to ecological and agricultural outcomes.Accordingly,critical gaps are identified—particularly the scarcity of multi-stress and field-based studies—and future directions that integrate omics approaches,systems biology,and eco-physiological frameworks are proposed.Understanding the costs of adaptation is essential not only for breeding resilient,high-yielding crops but also for ensuring their successful incorporation into sustainable agricultural practices under changing climate conditions.
基金supported by the National Key R&D Program of China(Grant No.2023YFF0716800)National Natural Science Foundation of China(Grant No.12102393).
文摘In the past decades,residual stresses have attracted wide attention due to their significant influences on material’s strength,fatigue life,and dimensional stability.Various residual stress measurement methods have been developed such as X-ray diffraction,neutron diffraction,crack compliance,and hole drilling.These methods may suffer from different disadvantages including radiation,high cost,destructive,unportable,etc.In this work,an in situ residual stress measurement method was proposed based on instrumented indentation using a piezoelectric bimorph cantilever.A Vickers’indenter was fabricated onto the free end of the cantilever for pressing into the sample and a strain gauge was bonded on the cantilever to monitor the indentation load.During testing,the contact area was extracted by tracking the cantilever’s contact resonance frequency based on the electromechanical impendence method.Different from traditional indentation-based methods that use a single hardness value to compute the residual stress,here the indentation force-contact area(F-S)curves with and without residual stresses were measured to derive the residual stress based on an empirical model.Experiments were then conducted on a specially designed CrMnCu specimen with different applied stresses.Results show that the measured residual stress values agreed well with the applied stresses monitored by a strain gauge.The proposed residual stress measurement method holds great promise for in situ residual stress estimation due to its portable apparatus,simple operation procedure and insensitiveness to testing environment.
基金The SEU Innovation Capability Enhancement Plan for Doctoral Students(No.CXJH_SEU 24115)Marine Economic Development Project of Guangdong Province(No.GDNRC[2022]25).
文摘The study aimed to address the issue of elevated residual stress levels in dissimilar girth welds of cast steel joints.To achieve this,the hybrid welding technology,which yields high welding speeds while simultaneously reducing residual stresses,has been introduced.This study utilizes a numerical simulation method to investigate the temperature and residual stress field in the hybrid welding of G20Mn5 casting-Q355 low-alloy steel welded pipe.A com-parison of the findings of this study with those of other welding processes revealed the technological advantages of hybrid welding.The research outcomes show that due to geometric discontinuities and material differences,the temperature field of the joint exhibits uneven distribution characteristics,and the peak temperatures on the Q355 steel side exceeds those on the G20Mn5 steel side.An evident stress gra-dient is present in the residual stress field of the joint post-welding,with peak stress located at the weld root on the Q355 steel.Compared with arc welding,the hybrid welding leads to decreased residual stresses and deformation,with high stress outside the heat-affected zone diminishing rapidly.Furthermore,it significantly improves the welding efficiency.This study elucidates the distribution and underlying causes of thermal and residual stress fields in dissimilar girth welds.This serves as a foundation for the application of hybrid welding technology in welded cast steel joints.
基金supported by the National Natural Science Foundation of China(32372802).
文摘Phosphorus(P)is an essential macronutrient required for plant growth,development,and resilience to environmental stresses.Its availability in soil and homeostasis within plants are strongly influenced by environmental conditions,with unfavorable environments and soil factors disrupting phosphate availability,absorption,transport,and utilization.Optimizing phosphate supply can alleviate the detrimental impacts of abiotic stresses,thereby supporting growth and improving stress tolerance.Recent studies reveal that abiotic stresses modulate phosphate signaling pathways and alter the expression of phosphate-responsive genes,often affecting key regulators of P homeostasis.Strategic manipulation of phosphate transporters and their regulatory pathways offers a promising approach to enhance plant adaptation to challenging environments.This review highlights current advances in understanding the molecular mechanisms that coordinate P-responsive gene expression and homeostasis pathways under fluctuating P availability and stress conditions.It emphasizes the critical role of P nutrition in enhancing plant stress tolerance through antioxidant activation,osmolyte accumulation,membrane stabilization,and metal-phosphate complex formation.An in-depth mechanistic understanding of P-stress interactions will inform the development of P-efficient and stress-resistant crop varieties and guide more sustainable P fertilizer management in agriculture.
文摘Wear is a prevalent issue across various industries. Spherical fused tungsten carbide (sFTC) reinforced nickel-aluminum bronze (NAB) matrix composite surface deposits have shown remarkable potential in mitigating wear by approximately 80%. However, the performance of these sFTC/NAB composite surface deposits is determined by their residual stress state, and the precise macroscopic and microscopic residual stresses within these composites have yet to be clearly established. To address this gap, we employed neutron diffraction to measure the residual stresses in the sFTC/NAB composite surface deposits and re-melted NAB samples produced via laser melt injection. Significant residual stresses were determined. The maximum tensile macro residual stress appears approximately 1-1.5 mm below the composite layer. Residual stresses accumulate with an increasing number of laser process tracks. The maximum tensile macro residual stress in the three-track samples reaches about 350 MPa. Preheating the base plate significantly reduces the levels of macroscopic residual stress. The WC phase displayed significant compressive thermal misfit residual stress magnitude, while the Cu matrix exhibited tensile thermal misfit residual stress. Preheating the base plate does not reduce microscopic thermal misfit residual stress levels. In addition, a finite element model was built to investigate temperature and residual stresses in the re-melted NAB samples. The predicted temperature history and residual stress agree with the experimental results.
基金funded by National Natural Science Foundation of China(grant no.32301870 to Chen Lin)Natural Science Foundation of Jiangsu Province(grant no.BK20230568 to Chen Lin)+3 种基金the Jiangsu Provincial Agricultural Science and Technology Independent Innovation Fund(grant no.CX(24)3124 to Chen Lin)Outstanding Ph.D.Programin Yangzhou(grant no.YZLYJFJH2022YXBS147 to Chen Lin)the General Project of Basic Scientific Research to colleges and universities in Jiangsu Province(grant no.22KJB210019 toChen Lin)the Priority Academic Program Development of Jiangsu Higher Education Institutions is greatly acknowledged.
文摘Glutathione S-transferases (GSTs) represent a large and diverse enzyme family ubiquitously distributed across the plant kingdom. These proteins catalyze the conjugation of glutathione (GSH) with electrophilic substrates in response to various stress conditions. Beyond their role in stress adaptation, certain GSTs are integral regulators of plant growth and development, contributing to a range of physiological processes. Most GST proteins exhibit dual enzymatic activities, functioning as both transferases and peroxidases, which enables their involvement in diverse cellular processes, including detoxification and stress responses. Recent advancements, particularly in X-ray crystallography, have enabled detailed structural analysis of GST proteins, significantly enhancing our understanding of their biological functions. This review offers a comprehensive overview of the classification and structural characteristics of GSTs in plants. It also highlights recent findings on their roles in plant growth and development, cell signaling, catalytic transport, and stress tolerance. Furthermore, key scientific challenges related to GSTs are discussed, focusing on their potential applications in agriculture. These insights aim to facilitate the screening of functional GST genes and support molecular breeding efforts across diverse crop species.
基金funded by the National Science Foundation of China(CN)(Nos.42090054,41922055,41931295)the Key Research and Development Program of Hubei Province of China(No.2020BCB079)。
文摘Landslides frequently occurred in Jurassic red strata in the Three Gorges Reservoir(TGR)region in China.The Jurassic strata consist of low mechanical strength and poor permeability of weak silty mudstone layer,which may cause slope instability during rainfall.In order to understand the strength behavior of Jurassic silty mudstone shear zone,the so-called Shizibao landslide located in Guojiaba Town,Zigui County,Three Gorges Reservoir(TGR)in China is selected as a case study.The shear strength of the silty mudstone shear zone is strongly influenced by both the water content and the normal stress.Therefore,a series of drained ring shear tests were carried out by varying the water contents(7%,12%,17%,and 20%,respectively)and normal stresses(200,300,400,and 500 kPa,respectively).The result revealed that the residual friction coefficient and residual friction angle were power function relationships with water content and normal stress.The peak cohesion of the silty mudstone slip zone increased with water content to a certain limit,above which the cohesion decreased.In contrast,the residual cohesion showed the opposite trend,indicating the cohesion recovery above a certain limit of water content.However,both the peak and residual friction angle of the silty mudstone slip zone were observed to decrease steadily with increased water content.Furthermore,the macroscopic morphological features of the shear surface showed that the sliding failure was developed under high normal stress at low water content,while discontinuous sliding surface and soil extrusion were occurred when the water content increased to a saturated degree.The localized liquefaction developed by excess pore water pressure reduced the frictional force within the shear zone.Finally,the combined effects of the slope excavation and precipitation ultimately lead to the failure of the silty mudstone slope;however,continuous rainfall is the main factor triggering sliding.
基金support of the Poznan Networking&Supercomputing Center(PCSS)calculation grant
文摘Rolling path squeezes and rolling residual stresses of large diameter circular saw body for wood, generated by rolling pressure from 10 up to 120 bar were examined. X-ray diffraction, Barkhausen noise (BN) and Full Width of the peak at a Half Maximum (FWHM) (o) methods for evaluation of residual stresses were used. Dependencies of a tangential rolling residual stresses inside rolling paths upon rolling pressure p (bar) and rolling area A (mm2) were evaluated. The rolling pressure, as large as 60 bar, resulting in the rolling squeeze as high as 0.04 mm2, and, tangential residual compression stresses inside a rolling path, as large as ?TI = ?822 MPa, was considered to be the largest for the practical application.
文摘In order to examine the effects of the decrease of future precipitation on the eco-physiological characteristics of sea buckthorn (Hippophae rhamnoides Linn.) in Huangfuchuan Watershed in Nei Mongol, a water gradient experiment was conducted based on the four specially designed water supply levels, including normal precipitation, slight drought, drought and extreme drought. Results of ANOVE showed that different water gradients had a significant effect on (1) microhabitat factors, such as soil water content and soil temperature; (2) gas exchange, such as net photosynthetic rate, stomatal conductance and transpiration rate; (3) resource use efficiency; and (4) leaf water potential. Water use efficiency of H rhamnoides could increase under moderate water stress, i.e. drought condition, while its net photosynthetic rate and transpiration rate decreased. All kinds of eco-physiological characteristics proved H. rhamnoides seedlings under all water supplies were affected by water stress more or less and that mechanism of intrinsic physiological regulation in seedlings under the extreme drought conditions had the appearance of turbulence to a certain extent. Therefore, H rhamnoides seedlings in Huangfuchuan Watershed could not acclimate to extreme drought conditions.
基金Project (51005154) supported by the National Natural Science Foundation of ChinaProject (12CG11) supported by the Chenguang Program of Shanghai Municipal Education Commission, ChinaProject (201104271) supported by the China Postdoctoral Science Foundation
文摘The effect of silicon doping on the residual stress of CVD diamond films is examined using both X-ray diffraction (XRD) analysis and Raman spectroscopy measurements. The examined Si-doped diamond films are deposited on WC-Co substrates in a home-made bias-enhanced HFCVD apparatus. Ethyl silicate (Si(OC2H5)4) is dissolved in acetone to obtain various Si/C mole ratio ranging from 0.1% to 1.4% in the reaction gas. Characterizations with SEM and XRD indicate increasing silicon concentration may result in grain size decreasing and diamond [110] texture becoming dominant. The residual stress values of as-deposited Si-doped diamond films are evaluated by both sin2ψ method, which measures the (220) diamond Bragg diffraction peaks using XRD, with ψ-values ranging from 0° to 45°, and Raman spectroscopy, which detects the diamond Raman peak shift from the natural diamond line at 1332 cm-1. The residual stress evolution on the silicon doping level estimated from the above two methods presents rather good agreements, exhibiting that all deposited Si-doped diamond films present compressive stress and the sample with Si/C mole ratio of 0.1% possesses the largest residual stress of ~1.75 GPa (Raman) or ~2.3 GPa (XRD). As the silicon doping level is up further, the residual stress reduces to a relative stable value around 1.3 GPa.
基金National Defence Pre-research Foundation of China (41312040404)
文摘The finite-element method has been used to study the thermal stress distribution in large-sized sapphire crystals grown with the sapphire growth technique with micro-pulling and shoulder-expanding at cooled center （SAPMAC） method. A critical defect model has been established to explain the growth and propagation of cracks during the sapphire growing process. It is demonstrated that the stress field depends on the growth rate, the ambient temperature and the crystallizing direction. High stresses always exist near the growth interfaces, at the shoulder-expanding locations, the tailing locations and the sites where the diameters undergo sharp changes. The maximum stresses always occur at the interface of seeds and crystals. Cracks often form in the critical defect region and spread in the m-planes and a-planes under applied tensile stresses during crystal growth. The experimental results have verified that with the improved system of crystal growth and well-controlled techniques, the large-sized sapphire crystals of high quality can be grown due to absence of cracks.
文摘Seven reinforced concrete （RC） beams with epoxy-bonded glass fiber reinforced plastic （GFRP） sheets and two control RC beams were experimentally tested to investigate the bond behavior of the interfaces between RC beams and GFRP sheets. The variable parameters considered in test beams are the layers of GFRP sheets, the bond lengths and the reinforcement ratios. The results indicate that the flexural strength of the repaired beams is increased, but the ultimate load of beams with GFRP sheets debonding failure is reduced relatively. The bond length is the main factor that results in bonding failure of the strengthened beams. An experimental method of interfacial shear stress is proposed to analyze the distribution of shear stress according to experimental results. The analytical method of shear and normal stresses and a simple equation are proposed to predict the peeling loads. The proposed model is applied to experimental beams. The analytical results show a good agreement with the experimental results.
基金Project(51375503)supported by the National Natural Science Foundation of China
文摘The stress aging behavior of Al-Cu alloy under various applied stresses, i.e., elastic stress, yield stress and plasticdeformation stress, was investigated using single crystals. The resulting microstructures and the yield strength were examined bytransmission electron microscopy （TEM） and compression tests, respectively. The results indicate that an elastic stress of 15 MPa ishigh enough to influence the precipitation distribution of θ′ during aging at 180℃. The applied stress loading along [116]Aldirection results in increased number density of θ′ on （001）Al habit planes. This result becomes more significant with increasingapplied stress and leads to lower yield strength of Al-Cu single crystals during aging. Moreover, the generation of the preferentialorientation of θ′ was discussed by the effect of the dislocation induced by applied stress as well as the role of the misfit between theθ′-precipitate and Al matrix. The results are in agreement with the effect of the latter one.
基金This work was financiallysupportedbythe Research Grants(NN-8501)from Ministry ofCommerce,Industry and Energyin Republic ofKorea.
文摘Several automotive parts such as door panels have been manufactured by using load-adapted blanks for crash optimization and weight minimization. Recently, Tailor Rolled Blanks (TRB) has been introduced to remove the disadvantages of a welding process which was used in joining panel components. TRB offers better structural design capabilities due to the seamless transitions on the panels with different thicknesses. In spite of the advantages of the process, TRB leaves internal stresses in the panel. This residual stresses lower the formability of Tailor Rolled Blanked (TRBed) parts and cause cracks near severe curvature during subsequent forming processes. In this research, the residual stresses of TRBed Al5J32-T4 sheets were studied by X-ray stress analysis, and also microstructure was observed along the rolling direction. In addition, heat treatment was done after TRB process in order to compare the residual stresses to that of the TRBed sheets before the heat treatment.
文摘Spur gears are widely used in the power transmission mechanism of several machines.Due to the transmitted torque,spur gears experience high stresses which could cause gear tooth failure by surface pitting or root fracture.Tip relief and other gear profile modification have been considered for reducing the induced stresses in the gear tooth.In this work,the influence of tip relief on stresses on a pair of identical spur gear was analyzed using commercial FEA software ANSYS,and formulae for estimating contact and bending stresses were derived.Three cases of gear sets were analyzed;a non-modified pair and another two sets with linear and parabolic tip relief profiles.The non-modified gear set frictionless contact stress was validated against the calculated AGMA pitting resistance,Hertzian contact stress and a reported contact stress value in the literature.The four methods agreed well with each other.Similarly,bending stress was also compared with the AGMA bending strength and Lewis bending stress for validation.Then,friction coefficient was varied from 0.0 to 0.3 with increment of 0.1.The gear contact stress increased up to 11%relative to the frictionless case,whereas bending stress decreased by 6%.Linear tip relief modification was carried out for increasing normalised tip relief values of 0.25 to 1.0 with increment of 0.25.The gear frictionless contact and bending stresses decreased by a maximum of 4%and 2%,respectively.Frictional contact stress increased by up to 7.1%and the bending stress is almost identical with the frictionless case.Parabolic tip relief was also carried out with similar normalised tip relief values.Frictionless contact stress decreased by 5%while frictional contact stress increased by up to 11.5%and the bending stress is also almost identical with the frictionless case.Finally,four formulae were introduced for estimating the contact and bending stresses for a tip modified spur gear.
基金The Program of International S&T Cooperation under contract No.2010DFA24470the National Science Foundation of China under contract No.41376101the Guangdong Provincial Science and Technology Planning Project under contract Nos 2012A030200002 and 2011B031100008
文摘On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating bottom shear stresses （BSS） and their effect on a sediment resuspension. Swell induced BSS have been found to be the most important part of the BSS. In this study, the correlation coefficient between a wavecurrent shear stress and SSC is 0.86, and that between current shear stresses and SSC is only 0.40. The peaks of the SSC are consistent with the height and the BSS of the swell. The swell is the main mechanism for the sediment re-suspension, and the tidal current effect on sediment re-suspension is small. The peaks of the SSC are centered on the high tidal level, and the flood tide enhances the wave shear stresses and the SSC near the bottom. The critical shear stress for sediment re-suspension at the observation station is between 0.20 and 0.30 N/m2. Tidal currents are too weak to stir up the bottom sediment into the flow, but a WCI （wave-current interaction） is strong enough to re-suspend the coarse sediment.
