The widespread use of herbicides such as glyphosate isopropyl amine salt(GIS)and atrazine(ATZ)poses significant risks to aquatic ecosystems.This study investigated the single and joint acute toxicity of a 1:1 GIS-ATZ ...The widespread use of herbicides such as glyphosate isopropyl amine salt(GIS)and atrazine(ATZ)poses significant risks to aquatic ecosystems.This study investigated the single and joint acute toxicity of a 1:1 GIS-ATZ mixture on zebrafish(Danio rerio).Acute tests determined 96-h LC_(50) values of 123.41 mg/L for GIS and 103.95 mg/L for ATZ.In the joint toxicity test,these values decreased to 60.96 and 50.88 mg/L,respectively.The Additive Index(AI)analysis revealed a consistent synergistic interaction between the herbicides at all exposure intervals.These findings underscore the enhanced ecological threat of herbicide mixtures and highlight the necessity of considering joint effects in environmental risk assessments.展开更多
A conceptual model of intermittent joints is introduced to the cyclic shear test in the laboratory to explore the effects of loading parameters on its shear behavior under cyclic shear loading.The results show that th...A conceptual model of intermittent joints is introduced to the cyclic shear test in the laboratory to explore the effects of loading parameters on its shear behavior under cyclic shear loading.The results show that the loading parameters(initial normal stress,normal stiffness,and shear velocity)determine propagation paths of the wing and secondary cracks in rock bridges during the initial shear cycle,creating different morphologies of macroscopic step-path rupture surfaces and asperities on them.The differences in stress state and rupture surface induce different cyclic shear responses.It shows that high initial normal stress accelerates asperity degradation,raises shear resistance,and promotes compression of intermittent joints.In addition,high normal stiffness provides higher normal stress and shear resistance during the initial cycles and inhibits the dilation and compression of intermittent joints.High shear velocity results in a higher shear resistance,greater dilation,and greater compression.Finally,shear strength is most sensitive to initial normal stress,followed by shear velocity and normal stiffness.Moreover,average dilation angle is most sensitive to initial normal stress,followed by normal stiffness and shear velocity.During the shear cycles,frictional coefficient is affected by asperity degradation,backfilling of rock debris,and frictional area,exhibiting a non-monotonic behavior.展开更多
The scale effect on shear strength of rock joints is well-documented.However,whether scale effects are negative,positive,or even exist or not is still controversial.Joint roughness significantly influences the shear s...The scale effect on shear strength of rock joints is well-documented.However,whether scale effects are negative,positive,or even exist or not is still controversial.Joint roughness significantly influences the shear strength of rock joints.Compared to the shear tests,using the joint roughness coefficient(JRC)and its roughness parameters offers a more convenient method for describing the scale effect on shear strength.However,it is crucial to understand that the scale effect mechanisms of JRC are distinct from those of shear strength.Therefore,this paper aims to clarify these distinct mechanisms.By digitally extracting roughness parameters from granite samples,it is found that the scale effect of roughness parameters mainly comes from the sampling methods and the geometric characteristics of parameters.Furthermore,a full data sampling method considering heterogeneity is proposed to obtain more representative roughness parameters.To reveal the scale effect mechanisms of shear strength,Gaussian filtering is firstly used to separate the waviness and unevenness components of roughness,facilitating a deeper understanding of the geometric characteristics of roughness.It is suggested that the wavelength of the waviness component can reflect the scale effect on shear strength.Secondly,numerical simulations of ideal artificial joint models are conducted to validate that the wavelength of the waviness component serves as the dividing point between positive and negative scale effects.The mechanical mechanisms of positive and negative scale effects are also interpreted.Finally,these mechanisms successfully elucidate the occurrence patterns of the scale effect on natural joint profiles.展开更多
The joint roughness coefficient(JRC) is one of the key parameters for evaluating the shear strength of rock joints.Because of the scale effect in the JRC,reliable JRC values are of great importance for most rock engin...The joint roughness coefficient(JRC) is one of the key parameters for evaluating the shear strength of rock joints.Because of the scale effect in the JRC,reliable JRC values are of great importance for most rock engineering projects.During the collection process of JRC samples,the redundancy or insufficiency of representative rock joint surface topography(RJST) information in serial length JRC samples is the essential reason that affects the reliability of the scale effect results.Therefore,this paper proposes an adaptive sampling method,in which we use the entropy consistency measure Q(a) to evaluate the consistency of the joint morphology information contained in adjacent JRC samples.Then the sampling interval is automatically adjusted according to the threshold Q(at) of the entropy consistency measure to ensure that the degree of change of RJST information between JRC samples is the same,and ultimately makes the representative RJST information in the collected JRC samples more balanced.The application results of actual cases show that the proposed method can obtain the scale effect in the JRC efficiently and reliably.展开更多
The clinical treatment of severe trauma withsternoclavicular joint injury is challenging,primarilydue to the irregular shape of the bones surrounding thesternoclavicular joint,as well as the posterior clavicle beingcl...The clinical treatment of severe trauma withsternoclavicular joint injury is challenging,primarilydue to the irregular shape of the bones surrounding thesternoclavicular joint,as well as the posterior clavicle beingclose to the aorta and mediastinal organs.^([1])These patientsnot only suffer direct injuries to the sternoclavicularjoint,but also frequently experience severe injuries toother body parts.The systemic physiological disordersand multi-organ dysfunction caused by severe traumaincrease the surgery di?culty and mortality risk.^([2])展开更多
Joint surface roughness is comprised of two components:large-scale(waviness,first-order)and smallscale(unevenness,second-order).To investigate the scale effect of two-order roughness,a surface area method is used to s...Joint surface roughness is comprised of two components:large-scale(waviness,first-order)and smallscale(unevenness,second-order).To investigate the scale effect of two-order roughness,a surface area method is used to separate the waviness and unevenness from the whole joint surface of each size.The results show that as the joint size increases,the first-order roughness exhibits a decrease,whereas the second-order roughness remains constant.This indicates that the roughness scale effect is primarily attributed to the waviness.Then,the influence of two-order roughness on the scale effect of joint shear strength is examined through a series of laboratory tests.The test results reveal a negative scale effect on the peak friction angle,which exhibits a strong correlation with the first-order roughness.The decrease in the peak friction angle with normal stress can be attributed primarily to the degradation of second-order roughness,which shows a negative exponential trend.Finally,an empirical model for estimating the peak friction angle of rock joints at different scales is proposed based on two-order roughness.The prediction accuracy of this model is validated by comparing the existing criteria.展开更多
Floating offshore wind turbine platforms typically use stiffened tubular joints at the connections between columns and braces.These joints are prone to fatigue due to complex weld geometries and the additional stress ...Floating offshore wind turbine platforms typically use stiffened tubular joints at the connections between columns and braces.These joints are prone to fatigue due to complex weld geometries and the additional stress concentrations caused by the stiffeners.Existing hot-spot stress approaches may be inadequate for analysing these joints because they do not simultaneously address weld-toe and weld-root failures.To address these limitations,this study evaluates the fatigue strength of stiffened tubular joints using the effective notch strain approach and the structural strain approach.Both methods account for fatigue at the weld toe and weld root and can be applied to both low-cycle fatigue(LCF)and high-cycle fatigue(HCF)regimes.Reanalyzes of a series of fatigue-tested specimens confirm the effectiveness of both approaches.The stiffener-shell fillet weld root is identified as the most critical fatigue location,which is consistent with fractographic observations.Although the brace-to-shell weld root exhibits lower stress levels in finite element(FE)models,weld quality was determined to be a crucial factor in fatigue failure.Furthermore,the results emphasise the importance of material plasticity in the LCF regime and demonstrate that full weld penetration significantly enhances fatigue strength.These findings provide valuable insights for the fatigue design of stiffened tubular joints in floating offshore wind turbine platforms.展开更多
In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE inte...In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE interface involves the accumulation of opposite charges on both sides of the interface,thereby complicating the comprehension of the interfacial charging phenomenon.This study investigates the fundamental mechanisms of charge accumulation and the associated homo-junction effect in homo-bilayer XLPE(H-XLPE).Space charge analysis,model calculations based on Maxwell's equations,and thermal stimulation depolarisation current(TSDC)measurements were performed.Space charge results show that the homo-junctioninduced charge accumulation causes greater electric field distortion,leading to lower breakdown strength of H-XLPE compared to single-layer XLPE.Model calculations indicate that the density of opposite charges on the interface is attributed to the local gradient of reciprocal conductivity in the H-XLPE interface region.TSDC measurements on XLPE and H-XLPE enabled extraction of trap parameters and analysis of the charge transport process.The findings provide experimental evidence and theoretical clue for elucidating the role of the interface area on the charge accumulation that affects reliability and stability of submarine cable systems.展开更多
Magnetostrictive effects and magnetocrystalline anisotropy are fundamental physical properties governing magnon dynamics in magnetic systems. Recent evidence shows that strain-mediated magnetostrictive coupling provid...Magnetostrictive effects and magnetocrystalline anisotropy are fundamental physical properties governing magnon dynamics in magnetic systems. Recent evidence shows that strain-mediated magnetostrictive coupling provides an effective pathway for modulating magnonic excitation through quantum interference. Nevertheless, the microscopic origins of magnetocrystalline anisotropy in manipulating magnon excitation pathways, particularly regarding magnonic Kerr nonlinearity and crystal direction constraints, require further investigation. In this study, we construct a dual-frequency driven magnomechanical model based on yttrium iron garnet(YIG) spheres. By introducing a Hamiltonian with the magnonic Kerr nonlinear term, we combine the Heisenberg–Langevin equations and the mean field approximation to analytically solve for the driving efficiency η, and we base our analysis on experimental parameters to evaluate the impacts of the magnonic Kerr coefficient(K), driving field(B_1) and YIG size. The results show that the magnetocrystalline anisotropy induces a MHz-scale frequency shift, splitting the transmission spectrum from a Lorentzian line shape into asymmetric Fano resonance double peaks. The orientation of the external magnetic field(aligned with the [100] or [110] crystallographic axis) allows precise control over the sign of the magnonic Kerr coefficient K, thereby enabling a reversal in the direction of the frequency shift. A strong driving field B_1 not only enables controllable switching of the state but also adjusts the switching bandwidth. Furthermore, we show the transition of the dynamical response mechanism of the excitation efficiency spectrum with varying YIG sphere sizes. The study shows the dynamic control mechanism of the magnetocrystalline anisotropy on magnon switching and provides a theoretical foundation for size optimization and nonlinear energy manipulation in spintronic device design.展开更多
The extensive co-occurrence of pyrethroid insecticides such as lambda-cyhalothrin(LCT)and cypermethrin(CPM)in aquatic systems poses a potential risk,yet a significant research gap exists regarding their combined toxic...The extensive co-occurrence of pyrethroid insecticides such as lambda-cyhalothrin(LCT)and cypermethrin(CPM)in aquatic systems poses a potential risk,yet a significant research gap exists regarding their combined toxicological effects.In this study,the single and joint acute toxicity effects of lambda-cyhalothrin(LCT)and cypermethrin(CPM)on Nile tilapia fingerlings were investigated using 96-h bioassays.Results showed both were highly toxic,with LCT(96-h LC 50=66.53μg/L)being four-fold more potent than CPM(259.41μg/L).Regression analysis confirmed positive correlation(P<0.01)between pesticide concentration and observed mortality.The binary mixture exhibited synergistic effect with Additive Index(AI)>0,indicating combined effects exceeded the sum of their individual actions.This synergism likely stems from mutual inhibition of metabolic detoxification pathways,leading to increased internal concentrations and amplified neurotoxicity.Generally,this study confirmed that single-compound risk assessments dangerously underestimate pyrethroid mixture hazards,necessitating their inclusion in regulatory frameworks for accurate aquatic biodiversity protection.展开更多
BACKGROUND In the management of postoperative pain following total joint arthroplasty(TJA),the use of nonsteroidal anti-inflammatory drugs,including acetaminophen,plays a key role in alleviating pain.However,the compa...BACKGROUND In the management of postoperative pain following total joint arthroplasty(TJA),the use of nonsteroidal anti-inflammatory drugs,including acetaminophen,plays a key role in alleviating pain.However,the comparison between intravenous and oral acetaminophen administration in patients undergoing full joint replacement surgery remains controversial.AIM To assess the effectiveness of intravenous and oral acetaminophen in alleviating pain and supporting rehabilitation following TJA.METHODS PubMed,Embase and the Cochrane Library were comprehensively searched to identify cohort studies.The effects of intravenous and oral acetaminophen for managing pain and supporting rehabilitation following TJA were analysed using randomized controlled trials.PRISMA guidelines were followed.The effectiveness of the administration routes was compared based on visual analogue scale(VAS)scores at 24 and 48 h,total morphine usage within 24 h,and total duration of hospital stay.RESULTS The meta-analysis included seven studies comparing intravenous acetaminophen groups and oral acetaminophen groups.The results demonstrated that oral acetaminophen was comparable to intravenous acetaminophen with regard to VAS scores at 24 h and 48 h(P=0.76 and 0.08,respectively).The difference in total morphine use between the two groups was not significant(P=0.22).However,the total hospital stay duration of the intravenous acetaminophen groups was significantly reduced compared to the oral acetaminophen groups(P=0.0005),showing significant advantages in optimizing postoperative recovery and shortening hospitalisation time.CONCLUSION After TJA surgery,intravenous injection of acetaminophen can shorten hospitalisation time and is suitable for rapid analgesia,Oral administration has become the preferred choice for mild cases due to its convenience and economy,providing a basis for clinical drug selection.展开更多
Transmission towers,serving as the support structure of transmission lines,are significant for the functional-ity of an electric transmission system.Bolt joint loosening is one of the critical factors that can affect ...Transmission towers,serving as the support structure of transmission lines,are significant for the functional-ity of an electric transmission system.Bolt joint loosening is one of the critical factors that can affect the safety and stability of transmission towers.In this study,the effects of bolt joint loosening on the dynamic characteristics of a 220-kV angle steel transmission tower are the main topic of concern.First,the mechanical properties of typical joints subjected to different degrees of bolt loosening are studied by finite solid-element simulation,based on which a finite hybrid-element modeling method is developed for a tower structure suffering varying loose degrees in the joints.Taking a 220-kV angle steel transmission tower as the object,the influence of the position and degree of loosening on the tower’s natural frequencies and mode shapes are simulated and discussed.The results demonstrate that the main-member splice joint and the main diagonal-horizontal member gusset plate joint account for the dominant impact on the dynamic characteristics of the tower.In addition,the dominant joint shifts from the main-member splice joint to the main diagonal-horizontal member gusset plate joint as the considered modal order increases.In the case of double joints loosening simultaneously,the loosening of nondomi-nant joints has nonnegligible effects on the tower as well.展开更多
Welded joints can be divided into different material zones,with considerable variation of material properties around the weld toe.The material inhomogeneity influences the local stress and strain of welded joints unde...Welded joints can be divided into different material zones,with considerable variation of material properties around the weld toe.The material inhomogeneity influences the local stress and strain of welded joints under monotonic and cyclic loading.This study aims to examine the local stress and strain characteristics of welded joints considering material inhomogeneity.Numerical models with various material zones were developed,and material properties were determined based on hardness.Smooth specimen models were used to analyze stress and strain distributions excluding notch effects.A detailed inhomogeneous model of a welded joint was established based on extensive microhardness measurements around the weld toe and the Kriging interpolation method.Additionally,a homogeneous model and a simplified inhomogeneous model,based on limited measured data,were generated and compared with the detailed inhomogeneous model.Fatigue life was estimated using the Smith,Watson,and Topper method based on the obtained stress and strain.For smooth specimen models,stress concentration occurs at a location where the strain is not significant,and fatigue cracks were most likely to initiate from the base metal.Results from the two simplified models showed deviations from those of the detailed inhomogeneous model,and the limitations of these simplified models are discussed.展开更多
In this study,the single and jiont acute toxicity effects of pendimethalin(herbicide)and fenitrothion(organophosphate insecticide)were investigated on juvenile zebrafish(Danio rerio)under semi-static conditions.Mortal...In this study,the single and jiont acute toxicity effects of pendimethalin(herbicide)and fenitrothion(organophosphate insecticide)were investigated on juvenile zebrafish(Danio rerio)under semi-static conditions.Mortality was assessed at 24,48,72,and 96 h.The study revealed that pendimethalin exhibited higher toxicity than fenitrothion.The 96-h LC 50 values were 0.477 mg/L for pendimethalin and 2.634 mg/L for fenitrothion.Joint exposure produced enhanced toxicity,with 96-h LC 50 values of 0.204 mg/L(pendimethalin equivalent)and 1.139 mg/L(fenitrothion equivalent).Regression analysis showed a significant positive correlation(p<0.05)between pesticide concentration and mortality,while toxicity indices confirmed synergistic interactions.These findings underscore the ecological risks posed by pesticide mixtures and highlight the importance of regulating pesticide use to safeguard aquatic organisms and maintain environmental sustainability.展开更多
In this paper,Desulfovibrio vulgaris corrosion of X80 steel welded joint with different heat inputs was carefully investigated.The results confirmed that in the sterile medium,general corrosion rate and lo-calized cor...In this paper,Desulfovibrio vulgaris corrosion of X80 steel welded joint with different heat inputs was carefully investigated.The results confirmed that in the sterile medium,general corrosion rate and lo-calized corrosion susceptibility of heat affected zone(HAZ)were higher than those of weld zone(WZ)and base metal(BM).In the inoculated medium,the general corrosion rate of HAZ was still higher than that of WZ and BM.However,the number and depth of corrosion pits on WZ and BM surfaces,as well as the localized corrosion susceptibility,were much higher than those in HAZ,which was opposite to that in sterile environment,suggesting that the Desulfovibrio vulgaris corrosion of the welded joint was selective.With heat input increasing from 0.57 kJ/mm to 1.29 kJ/mm,general corrosion rate and localized corrosion susceptibility of HAZ and WZ simultaneously decreased in sterile or inoculated medium.In in-oculated medium,localized corrosion of HAZ decreased more sharply than weld zone.Within the range of heat inputs tested,the study discerned a positive correlation:higher heat inputs correlated with an enhanced corrosion resistance of welded joint,irrespective of environmental conditions being sterile or inoculated.The findings provide a solid basis for the welding parameter determination to steel pipelines in oil and gas transportation.展开更多
Prolonged cyclic water intrusion has progressively developed joints in the hydro-fluctuation belt,elevating the instability risk of reservoir bank slopes.To investigate its impact on joint shear damage evolution,joint...Prolonged cyclic water intrusion has progressively developed joints in the hydro-fluctuation belt,elevating the instability risk of reservoir bank slopes.To investigate its impact on joint shear damage evolution,joint samples were prepared using three representative roughness curves and subjected to direct shear testing following cyclic water intrusion.A shear damage constitutive model considering the coupling effect of cyclic water intrusion and load was developed based on macroscopic phenomenological damage mechanics and micro-statistical theory.Results indicate:(1)All critical shear mechanical parameters(including peak shear strength,shear stiffness,basic friction angle,and joint compressive strength)exhibit progressive deterioration with increasing water intrusion cycles;(2)Model validation through experimental curve comparisons confirms its reliability.The model demonstrates that intensified water intrusion cycles reduce key mechanical indices,inducing a brittle-to-ductile transition in joint surface deformation—a behavior consistent with experimental observations;(3)Damage under cyclic water intrusion and load coupling follows an S-shaped trend,divided into stabilization(water-dominated stage),development(load-dominated stage),and completion stages.The research provides valuable insights for stability studies,such as similar model experiments for reservoir bank slopes and other water-related projects.展开更多
This study attempted to assess the lethal concentration(96-h LC_(50))effects of imidacloprid(neonicotinoid pesticide),thiamethoxam(neonicotinoid pesticide),and their combination on juvenile Zebrafish(Danio rerio).Each...This study attempted to assess the lethal concentration(96-h LC_(50))effects of imidacloprid(neonicotinoid pesticide),thiamethoxam(neonicotinoid pesticide),and their combination on juvenile Zebrafish(Danio rerio).Each set of trials contained a control(de-chlorinated tap water),and the experiments were repeated three times.The fish(n=10)were randomly measured with an average length of(3.4±0.34)cm and weight of(1±0.1)g.The temperature was kept at 24℃.Experiments 1 and 2 were designed to investigate at the acute toxicity of imidacloprid and thiamethoxam on juvenile zebrafish(Danio rerio)respectively,whereas experiment 3 was aimed at the combined toxicity of IMI and THM on zebrafish.The tests followed the same study design,and each experiment used seven different logarithmic concentrations of imidacloprid insecticides(310.00,317.08,324.33,331.74,339.32,347.07,355.00 mg/L)and thiamethoxam(175.00,185.52,200.93,215.30,230.70,247.20,264.88 mg/L).The results show that THM is more toxic than IMI,with LC_(50)values of 190.34 mg/L for THM and 310.92 mg/L for IMI.Both individual toxicities showed a substantial positive connection(P<0.05)with confidence limits of 321.50-300.68 mg/L for IMI and 199.91-181.21 mg/L for THM.The joint toxicity test was carried out using the 96-h LC_(50)values of imidacloprid and thiamethoxam obtained in the individual acute toxicity trials at a 1:1 ratio.The Additive Index(AI)demonstrated that imidacloprid and thiamethoxam acted synergistically on D.rerio.As a matter of fact,more research is needed to better understand the impact of IMI and THM on other aquatic organisms and also create strategies to mitigate its harmful effects on aquatic life.展开更多
To address the issue of extreme thermal-induced arching in CRTS II slab tracks due to joint damage,an optimized joint repair model was proposed.First,the formula for calculating the safe temperature rise of the track ...To address the issue of extreme thermal-induced arching in CRTS II slab tracks due to joint damage,an optimized joint repair model was proposed.First,the formula for calculating the safe temperature rise of the track was derived based on the principle of stationary potential energy.Considering interlayer evolution and structural crack propagation,an optimized joint repair model for the track was established and validated.Subsequently,the impact of joint repair on track damage and arch stability under extreme temperatures was studied,and a comprehensive evaluation of the feasibility of joint repair and the evolution of damage after repair was conducted.The results show that after the joint repair,the temperature rise of the initial damage of the track structure can be increased by 11℃.Under the most unfavorable heating load with a superimposed temperature gradient,the maximum stiffness degradation index SDEG in the track structure is reduced by about 81.16%following joint repair.The joint repair process could effectively reduce the deformation of the slab arching under high temperatures,resulting in a reduction of 93.96%in upward arching deformation.After repair,with the damage to interfacing shear strength,the track arch increases by 2.616 mm.展开更多
Objective:To evaluate the treatment effect of total hip arthroplasty(THA)for intertrochanteric femur fractures(IFF)in elderly patients.Methods:Thirty-two elderly patients with IFF admitted to the hospital from August ...Objective:To evaluate the treatment effect of total hip arthroplasty(THA)for intertrochanteric femur fractures(IFF)in elderly patients.Methods:Thirty-two elderly patients with IFF admitted to the hospital from August 2021 to August 2024 were selected and randomly divided into two groups using a random number table.The experimental group(16 patients)underwent THA surgery,while the control group(16 patients)underwent proximal femoral nail antirotation(PFNA)surgery.Hip joint function and quality of life indicators were compared between the two groups.Results:Before surgery,there was no significant difference in hip joint function and quality of life scores between the two groups(P>0.05).However,at six months postoperatively,the experimental group had higher hip joint function and quality of life scores compared to the control group(P<0.05).The total effective rate was higher in the experimental group than in the control group(P<0.05).The complication rate in the experimental group was similar to that in the control group(P>0.05).Conclusion:THA can improve the clinical efficacy of elderly patients with IFF,minimize postoperative complications,effectively restore hip joint function,and optimize postoperative quality of life.展开更多
Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms lig...Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms ligand bonds or hydrogen bonds with sulfur ions in lithium polysulfides(LiPSs),thus inhibiting the shuttle effect.Electrochemical analyses demonstrated that lithium‑sulfur(Li‑S)batteries employing the NH2‑SS interlayer exhibited discharge specific capacities of 1048 and 789 mAh·g^(-1) at 0.2C and 2C,respectively,and even at 4C,the initial discharge specific capacity remained at 590 mAh·g^(-1),outperforming the Li‑S battery with unmodified SS as the interlayer.展开更多
基金Supported by The Central Public-Interest Scientific Institution Basal Research Fund,CAFS(2025XT0902)Earmarked for China Agriculture Research System(CARS-46).
文摘The widespread use of herbicides such as glyphosate isopropyl amine salt(GIS)and atrazine(ATZ)poses significant risks to aquatic ecosystems.This study investigated the single and joint acute toxicity of a 1:1 GIS-ATZ mixture on zebrafish(Danio rerio).Acute tests determined 96-h LC_(50) values of 123.41 mg/L for GIS and 103.95 mg/L for ATZ.In the joint toxicity test,these values decreased to 60.96 and 50.88 mg/L,respectively.The Additive Index(AI)analysis revealed a consistent synergistic interaction between the herbicides at all exposure intervals.These findings underscore the enhanced ecological threat of herbicide mixtures and highlight the necessity of considering joint effects in environmental risk assessments.
基金financially supported by the National Natural Science Foundation of China(Grant No.42172292)Taishan Scholars Project Special Funding,and Shandong Energy Group(Grant No.SNKJ 2022A01-R26).
文摘A conceptual model of intermittent joints is introduced to the cyclic shear test in the laboratory to explore the effects of loading parameters on its shear behavior under cyclic shear loading.The results show that the loading parameters(initial normal stress,normal stiffness,and shear velocity)determine propagation paths of the wing and secondary cracks in rock bridges during the initial shear cycle,creating different morphologies of macroscopic step-path rupture surfaces and asperities on them.The differences in stress state and rupture surface induce different cyclic shear responses.It shows that high initial normal stress accelerates asperity degradation,raises shear resistance,and promotes compression of intermittent joints.In addition,high normal stiffness provides higher normal stress and shear resistance during the initial cycles and inhibits the dilation and compression of intermittent joints.High shear velocity results in a higher shear resistance,greater dilation,and greater compression.Finally,shear strength is most sensitive to initial normal stress,followed by shear velocity and normal stiffness.Moreover,average dilation angle is most sensitive to initial normal stress,followed by normal stiffness and shear velocity.During the shear cycles,frictional coefficient is affected by asperity degradation,backfilling of rock debris,and frictional area,exhibiting a non-monotonic behavior.
基金funded by the National Natural Science Foundation Projects(Grant Nos.41772287 and 42277132)the Key R&D Project of Zhejiang Province(Grant No.2021C03159).
文摘The scale effect on shear strength of rock joints is well-documented.However,whether scale effects are negative,positive,or even exist or not is still controversial.Joint roughness significantly influences the shear strength of rock joints.Compared to the shear tests,using the joint roughness coefficient(JRC)and its roughness parameters offers a more convenient method for describing the scale effect on shear strength.However,it is crucial to understand that the scale effect mechanisms of JRC are distinct from those of shear strength.Therefore,this paper aims to clarify these distinct mechanisms.By digitally extracting roughness parameters from granite samples,it is found that the scale effect of roughness parameters mainly comes from the sampling methods and the geometric characteristics of parameters.Furthermore,a full data sampling method considering heterogeneity is proposed to obtain more representative roughness parameters.To reveal the scale effect mechanisms of shear strength,Gaussian filtering is firstly used to separate the waviness and unevenness components of roughness,facilitating a deeper understanding of the geometric characteristics of roughness.It is suggested that the wavelength of the waviness component can reflect the scale effect on shear strength.Secondly,numerical simulations of ideal artificial joint models are conducted to validate that the wavelength of the waviness component serves as the dividing point between positive and negative scale effects.The mechanical mechanisms of positive and negative scale effects are also interpreted.Finally,these mechanisms successfully elucidate the occurrence patterns of the scale effect on natural joint profiles.
基金supported by the National Natural Science Foundation of China(No.42207175)。
文摘The joint roughness coefficient(JRC) is one of the key parameters for evaluating the shear strength of rock joints.Because of the scale effect in the JRC,reliable JRC values are of great importance for most rock engineering projects.During the collection process of JRC samples,the redundancy or insufficiency of representative rock joint surface topography(RJST) information in serial length JRC samples is the essential reason that affects the reliability of the scale effect results.Therefore,this paper proposes an adaptive sampling method,in which we use the entropy consistency measure Q(a) to evaluate the consistency of the joint morphology information contained in adjacent JRC samples.Then the sampling interval is automatically adjusted according to the threshold Q(at) of the entropy consistency measure to ensure that the degree of change of RJST information between JRC samples is the same,and ultimately makes the representative RJST information in the collected JRC samples more balanced.The application results of actual cases show that the proposed method can obtain the scale effect in the JRC efficiently and reliably.
文摘The clinical treatment of severe trauma withsternoclavicular joint injury is challenging,primarilydue to the irregular shape of the bones surrounding thesternoclavicular joint,as well as the posterior clavicle beingclose to the aorta and mediastinal organs.^([1])These patientsnot only suffer direct injuries to the sternoclavicularjoint,but also frequently experience severe injuries toother body parts.The systemic physiological disordersand multi-organ dysfunction caused by severe traumaincrease the surgery di?culty and mortality risk.^([2])
基金supported by the National Natural Science Foundation of China(Grant Nos.42272333 and 42377154)the Ningbo Natural Science Foundation(Grant No.2023J085).
文摘Joint surface roughness is comprised of two components:large-scale(waviness,first-order)and smallscale(unevenness,second-order).To investigate the scale effect of two-order roughness,a surface area method is used to separate the waviness and unevenness from the whole joint surface of each size.The results show that as the joint size increases,the first-order roughness exhibits a decrease,whereas the second-order roughness remains constant.This indicates that the roughness scale effect is primarily attributed to the waviness.Then,the influence of two-order roughness on the scale effect of joint shear strength is examined through a series of laboratory tests.The test results reveal a negative scale effect on the peak friction angle,which exhibits a strong correlation with the first-order roughness.The decrease in the peak friction angle with normal stress can be attributed primarily to the degradation of second-order roughness,which shows a negative exponential trend.Finally,an empirical model for estimating the peak friction angle of rock joints at different scales is proposed based on two-order roughness.The prediction accuracy of this model is validated by comparing the existing criteria.
基金supported by the National Natural Science Foundation of China(Grant No.52101350).
文摘Floating offshore wind turbine platforms typically use stiffened tubular joints at the connections between columns and braces.These joints are prone to fatigue due to complex weld geometries and the additional stress concentrations caused by the stiffeners.Existing hot-spot stress approaches may be inadequate for analysing these joints because they do not simultaneously address weld-toe and weld-root failures.To address these limitations,this study evaluates the fatigue strength of stiffened tubular joints using the effective notch strain approach and the structural strain approach.Both methods account for fatigue at the weld toe and weld root and can be applied to both low-cycle fatigue(LCF)and high-cycle fatigue(HCF)regimes.Reanalyzes of a series of fatigue-tested specimens confirm the effectiveness of both approaches.The stiffener-shell fillet weld root is identified as the most critical fatigue location,which is consistent with fractographic observations.Although the brace-to-shell weld root exhibits lower stress levels in finite element(FE)models,weld quality was determined to be a crucial factor in fatigue failure.Furthermore,the results emphasise the importance of material plasticity in the LCF regime and demonstrate that full weld penetration significantly enhances fatigue strength.These findings provide valuable insights for the fatigue design of stiffened tubular joints in floating offshore wind turbine platforms.
基金supported by Program of Beijing Huairou Laboratory(Grant ZD2022003A).
文摘In high-voltage direct current cable systems,the factory joint of cross-linked polyethylene(XLPE)-insulated cables presents significant electrical breakdown risk.The charge accumulation mechanism at the XLPE-XLPE interface involves the accumulation of opposite charges on both sides of the interface,thereby complicating the comprehension of the interfacial charging phenomenon.This study investigates the fundamental mechanisms of charge accumulation and the associated homo-junction effect in homo-bilayer XLPE(H-XLPE).Space charge analysis,model calculations based on Maxwell's equations,and thermal stimulation depolarisation current(TSDC)measurements were performed.Space charge results show that the homo-junctioninduced charge accumulation causes greater electric field distortion,leading to lower breakdown strength of H-XLPE compared to single-layer XLPE.Model calculations indicate that the density of opposite charges on the interface is attributed to the local gradient of reciprocal conductivity in the H-XLPE interface region.TSDC measurements on XLPE and H-XLPE enabled extraction of trap parameters and analysis of the charge transport process.The findings provide experimental evidence and theoretical clue for elucidating the role of the interface area on the charge accumulation that affects reliability and stability of submarine cable systems.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12022507 and 11774113)。
文摘Magnetostrictive effects and magnetocrystalline anisotropy are fundamental physical properties governing magnon dynamics in magnetic systems. Recent evidence shows that strain-mediated magnetostrictive coupling provides an effective pathway for modulating magnonic excitation through quantum interference. Nevertheless, the microscopic origins of magnetocrystalline anisotropy in manipulating magnon excitation pathways, particularly regarding magnonic Kerr nonlinearity and crystal direction constraints, require further investigation. In this study, we construct a dual-frequency driven magnomechanical model based on yttrium iron garnet(YIG) spheres. By introducing a Hamiltonian with the magnonic Kerr nonlinear term, we combine the Heisenberg–Langevin equations and the mean field approximation to analytically solve for the driving efficiency η, and we base our analysis on experimental parameters to evaluate the impacts of the magnonic Kerr coefficient(K), driving field(B_1) and YIG size. The results show that the magnetocrystalline anisotropy induces a MHz-scale frequency shift, splitting the transmission spectrum from a Lorentzian line shape into asymmetric Fano resonance double peaks. The orientation of the external magnetic field(aligned with the [100] or [110] crystallographic axis) allows precise control over the sign of the magnonic Kerr coefficient K, thereby enabling a reversal in the direction of the frequency shift. A strong driving field B_1 not only enables controllable switching of the state but also adjusts the switching bandwidth. Furthermore, we show the transition of the dynamical response mechanism of the excitation efficiency spectrum with varying YIG sphere sizes. The study shows the dynamic control mechanism of the magnetocrystalline anisotropy on magnon switching and provides a theoretical foundation for size optimization and nonlinear energy manipulation in spintronic device design.
基金Supported by The Central Public-Interest Scientific Institution Basal Research Fund,CAFS(2025XT0902)Earmarked Fund for China Agriculture Research System(CARS-46).
文摘The extensive co-occurrence of pyrethroid insecticides such as lambda-cyhalothrin(LCT)and cypermethrin(CPM)in aquatic systems poses a potential risk,yet a significant research gap exists regarding their combined toxicological effects.In this study,the single and joint acute toxicity effects of lambda-cyhalothrin(LCT)and cypermethrin(CPM)on Nile tilapia fingerlings were investigated using 96-h bioassays.Results showed both were highly toxic,with LCT(96-h LC 50=66.53μg/L)being four-fold more potent than CPM(259.41μg/L).Regression analysis confirmed positive correlation(P<0.01)between pesticide concentration and observed mortality.The binary mixture exhibited synergistic effect with Additive Index(AI)>0,indicating combined effects exceeded the sum of their individual actions.This synergism likely stems from mutual inhibition of metabolic detoxification pathways,leading to increased internal concentrations and amplified neurotoxicity.Generally,this study confirmed that single-compound risk assessments dangerously underestimate pyrethroid mixture hazards,necessitating their inclusion in regulatory frameworks for accurate aquatic biodiversity protection.
基金Supported by National Natural Science Foundation of China,No.11772226 and No.81572154.
文摘BACKGROUND In the management of postoperative pain following total joint arthroplasty(TJA),the use of nonsteroidal anti-inflammatory drugs,including acetaminophen,plays a key role in alleviating pain.However,the comparison between intravenous and oral acetaminophen administration in patients undergoing full joint replacement surgery remains controversial.AIM To assess the effectiveness of intravenous and oral acetaminophen in alleviating pain and supporting rehabilitation following TJA.METHODS PubMed,Embase and the Cochrane Library were comprehensively searched to identify cohort studies.The effects of intravenous and oral acetaminophen for managing pain and supporting rehabilitation following TJA were analysed using randomized controlled trials.PRISMA guidelines were followed.The effectiveness of the administration routes was compared based on visual analogue scale(VAS)scores at 24 and 48 h,total morphine usage within 24 h,and total duration of hospital stay.RESULTS The meta-analysis included seven studies comparing intravenous acetaminophen groups and oral acetaminophen groups.The results demonstrated that oral acetaminophen was comparable to intravenous acetaminophen with regard to VAS scores at 24 h and 48 h(P=0.76 and 0.08,respectively).The difference in total morphine use between the two groups was not significant(P=0.22).However,the total hospital stay duration of the intravenous acetaminophen groups was significantly reduced compared to the oral acetaminophen groups(P=0.0005),showing significant advantages in optimizing postoperative recovery and shortening hospitalisation time.CONCLUSION After TJA surgery,intravenous injection of acetaminophen can shorten hospitalisation time and is suitable for rapid analgesia,Oral administration has become the preferred choice for mild cases due to its convenience and economy,providing a basis for clinical drug selection.
基金The Youth Foundation Project of Jiangsu Province(No.BK20230337)the Natural Science Research of Jiangsu Higher Education Institutions of China(No.22KJB560004)the National Natu-ral Science Foundation of China(No.52278523)。
文摘Transmission towers,serving as the support structure of transmission lines,are significant for the functional-ity of an electric transmission system.Bolt joint loosening is one of the critical factors that can affect the safety and stability of transmission towers.In this study,the effects of bolt joint loosening on the dynamic characteristics of a 220-kV angle steel transmission tower are the main topic of concern.First,the mechanical properties of typical joints subjected to different degrees of bolt loosening are studied by finite solid-element simulation,based on which a finite hybrid-element modeling method is developed for a tower structure suffering varying loose degrees in the joints.Taking a 220-kV angle steel transmission tower as the object,the influence of the position and degree of loosening on the tower’s natural frequencies and mode shapes are simulated and discussed.The results demonstrate that the main-member splice joint and the main diagonal-horizontal member gusset plate joint account for the dominant impact on the dynamic characteristics of the tower.In addition,the dominant joint shifts from the main-member splice joint to the main diagonal-horizontal member gusset plate joint as the considered modal order increases.In the case of double joints loosening simultaneously,the loosening of nondomi-nant joints has nonnegligible effects on the tower as well.
基金Supported by the National Natural Science Foundation of China(52101350).
文摘Welded joints can be divided into different material zones,with considerable variation of material properties around the weld toe.The material inhomogeneity influences the local stress and strain of welded joints under monotonic and cyclic loading.This study aims to examine the local stress and strain characteristics of welded joints considering material inhomogeneity.Numerical models with various material zones were developed,and material properties were determined based on hardness.Smooth specimen models were used to analyze stress and strain distributions excluding notch effects.A detailed inhomogeneous model of a welded joint was established based on extensive microhardness measurements around the weld toe and the Kriging interpolation method.Additionally,a homogeneous model and a simplified inhomogeneous model,based on limited measured data,were generated and compared with the detailed inhomogeneous model.Fatigue life was estimated using the Smith,Watson,and Topper method based on the obtained stress and strain.For smooth specimen models,stress concentration occurs at a location where the strain is not significant,and fatigue cracks were most likely to initiate from the base metal.Results from the two simplified models showed deviations from those of the detailed inhomogeneous model,and the limitations of these simplified models are discussed.
基金Supported by The Central Public-Interest Scientific Institution Basal Research Fund,CAFS(2025XT0902)Earmarked Fund for China Agriculture Research System(CARS-46).
文摘In this study,the single and jiont acute toxicity effects of pendimethalin(herbicide)and fenitrothion(organophosphate insecticide)were investigated on juvenile zebrafish(Danio rerio)under semi-static conditions.Mortality was assessed at 24,48,72,and 96 h.The study revealed that pendimethalin exhibited higher toxicity than fenitrothion.The 96-h LC 50 values were 0.477 mg/L for pendimethalin and 2.634 mg/L for fenitrothion.Joint exposure produced enhanced toxicity,with 96-h LC 50 values of 0.204 mg/L(pendimethalin equivalent)and 1.139 mg/L(fenitrothion equivalent).Regression analysis showed a significant positive correlation(p<0.05)between pesticide concentration and mortality,while toxicity indices confirmed synergistic interactions.These findings underscore the ecological risks posed by pesticide mixtures and highlight the importance of regulating pesticide use to safeguard aquatic organisms and maintain environmental sustainability.
基金supported by the National Natural Science Foundation of China(Nos.52471096 and 51971191).
文摘In this paper,Desulfovibrio vulgaris corrosion of X80 steel welded joint with different heat inputs was carefully investigated.The results confirmed that in the sterile medium,general corrosion rate and lo-calized corrosion susceptibility of heat affected zone(HAZ)were higher than those of weld zone(WZ)and base metal(BM).In the inoculated medium,the general corrosion rate of HAZ was still higher than that of WZ and BM.However,the number and depth of corrosion pits on WZ and BM surfaces,as well as the localized corrosion susceptibility,were much higher than those in HAZ,which was opposite to that in sterile environment,suggesting that the Desulfovibrio vulgaris corrosion of the welded joint was selective.With heat input increasing from 0.57 kJ/mm to 1.29 kJ/mm,general corrosion rate and localized corrosion susceptibility of HAZ and WZ simultaneously decreased in sterile or inoculated medium.In in-oculated medium,localized corrosion of HAZ decreased more sharply than weld zone.Within the range of heat inputs tested,the study discerned a positive correlation:higher heat inputs correlated with an enhanced corrosion resistance of welded joint,irrespective of environmental conditions being sterile or inoculated.The findings provide a solid basis for the welding parameter determination to steel pipelines in oil and gas transportation.
基金supported by Shandong Provincial Colleges and Universities Youth Innovation Technol ogy Support Program(No.2023KJ092)Natural Science Foundation of Shandong Province(No.ZR2024ME060)Key Laboratory of Geological Safety of Coastal Urban Underground Space,Ministry of Natural Resources(No.BHKF2024Z06)。
文摘Prolonged cyclic water intrusion has progressively developed joints in the hydro-fluctuation belt,elevating the instability risk of reservoir bank slopes.To investigate its impact on joint shear damage evolution,joint samples were prepared using three representative roughness curves and subjected to direct shear testing following cyclic water intrusion.A shear damage constitutive model considering the coupling effect of cyclic water intrusion and load was developed based on macroscopic phenomenological damage mechanics and micro-statistical theory.Results indicate:(1)All critical shear mechanical parameters(including peak shear strength,shear stiffness,basic friction angle,and joint compressive strength)exhibit progressive deterioration with increasing water intrusion cycles;(2)Model validation through experimental curve comparisons confirms its reliability.The model demonstrates that intensified water intrusion cycles reduce key mechanical indices,inducing a brittle-to-ductile transition in joint surface deformation—a behavior consistent with experimental observations;(3)Damage under cyclic water intrusion and load coupling follows an S-shaped trend,divided into stabilization(water-dominated stage),development(load-dominated stage),and completion stages.The research provides valuable insights for stability studies,such as similar model experiments for reservoir bank slopes and other water-related projects.
基金Supported by the Central Public-interest Scientific Institution Basal Research Fund,CAFS(2025XT0902)the earmarked fund for China Agriculture Research System(CARS-46).
文摘This study attempted to assess the lethal concentration(96-h LC_(50))effects of imidacloprid(neonicotinoid pesticide),thiamethoxam(neonicotinoid pesticide),and their combination on juvenile Zebrafish(Danio rerio).Each set of trials contained a control(de-chlorinated tap water),and the experiments were repeated three times.The fish(n=10)were randomly measured with an average length of(3.4±0.34)cm and weight of(1±0.1)g.The temperature was kept at 24℃.Experiments 1 and 2 were designed to investigate at the acute toxicity of imidacloprid and thiamethoxam on juvenile zebrafish(Danio rerio)respectively,whereas experiment 3 was aimed at the combined toxicity of IMI and THM on zebrafish.The tests followed the same study design,and each experiment used seven different logarithmic concentrations of imidacloprid insecticides(310.00,317.08,324.33,331.74,339.32,347.07,355.00 mg/L)and thiamethoxam(175.00,185.52,200.93,215.30,230.70,247.20,264.88 mg/L).The results show that THM is more toxic than IMI,with LC_(50)values of 190.34 mg/L for THM and 310.92 mg/L for IMI.Both individual toxicities showed a substantial positive connection(P<0.05)with confidence limits of 321.50-300.68 mg/L for IMI and 199.91-181.21 mg/L for THM.The joint toxicity test was carried out using the 96-h LC_(50)values of imidacloprid and thiamethoxam obtained in the individual acute toxicity trials at a 1:1 ratio.The Additive Index(AI)demonstrated that imidacloprid and thiamethoxam acted synergistically on D.rerio.As a matter of fact,more research is needed to better understand the impact of IMI and THM on other aquatic organisms and also create strategies to mitigate its harmful effects on aquatic life.
基金Project(K2022G038)supported by the Science Technology Research and Development Program of China State Railway Group Co.,LtdProject(52178405)supported by the National Natural Science Foundation of China。
文摘To address the issue of extreme thermal-induced arching in CRTS II slab tracks due to joint damage,an optimized joint repair model was proposed.First,the formula for calculating the safe temperature rise of the track was derived based on the principle of stationary potential energy.Considering interlayer evolution and structural crack propagation,an optimized joint repair model for the track was established and validated.Subsequently,the impact of joint repair on track damage and arch stability under extreme temperatures was studied,and a comprehensive evaluation of the feasibility of joint repair and the evolution of damage after repair was conducted.The results show that after the joint repair,the temperature rise of the initial damage of the track structure can be increased by 11℃.Under the most unfavorable heating load with a superimposed temperature gradient,the maximum stiffness degradation index SDEG in the track structure is reduced by about 81.16%following joint repair.The joint repair process could effectively reduce the deformation of the slab arching under high temperatures,resulting in a reduction of 93.96%in upward arching deformation.After repair,with the damage to interfacing shear strength,the track arch increases by 2.616 mm.
文摘Objective:To evaluate the treatment effect of total hip arthroplasty(THA)for intertrochanteric femur fractures(IFF)in elderly patients.Methods:Thirty-two elderly patients with IFF admitted to the hospital from August 2021 to August 2024 were selected and randomly divided into two groups using a random number table.The experimental group(16 patients)underwent THA surgery,while the control group(16 patients)underwent proximal femoral nail antirotation(PFNA)surgery.Hip joint function and quality of life indicators were compared between the two groups.Results:Before surgery,there was no significant difference in hip joint function and quality of life scores between the two groups(P>0.05).However,at six months postoperatively,the experimental group had higher hip joint function and quality of life scores compared to the control group(P<0.05).The total effective rate was higher in the experimental group than in the control group(P<0.05).The complication rate in the experimental group was similar to that in the control group(P>0.05).Conclusion:THA can improve the clinical efficacy of elderly patients with IFF,minimize postoperative complications,effectively restore hip joint function,and optimize postoperative quality of life.
文摘Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms ligand bonds or hydrogen bonds with sulfur ions in lithium polysulfides(LiPSs),thus inhibiting the shuttle effect.Electrochemical analyses demonstrated that lithium‑sulfur(Li‑S)batteries employing the NH2‑SS interlayer exhibited discharge specific capacities of 1048 and 789 mAh·g^(-1) at 0.2C and 2C,respectively,and even at 4C,the initial discharge specific capacity remained at 590 mAh·g^(-1),outperforming the Li‑S battery with unmodified SS as the interlayer.
