Attributing to the noteworthy volume change of silicon active particles upon cycling,the porosity of the coated silicon composite electrode can vary significantly and therefore be expected to affect the apparent mecha...Attributing to the noteworthy volume change of silicon active particles upon cycling,the porosity of the coated silicon composite electrode can vary significantly and therefore be expected to affect the apparent mechanical response of the composite electrode.However,direct experimental evidence is still lacking.By stripping the active layer from the current collector and performing quasi-static stretching tests,this work shows a direct correlation between the variation of tensile properties and related coating porosity of the silicon composite electrode during lithiation.Although silicon particles soften when lithiated,it is found that the increased particle volume can significantly lower the porosity of the coating,resulting in the densification of the silicon composite electrode and thus reducing the toughness of the silicon composite electrode and making the electrode more prone to lose its mechanical integrity under small strain in service.Based on finite element simulation and experimental data analysis,analytical expressions of equivalent modulus and strength of the porous silicon composite electrode were also constructed and are in good agreement with the experimental values.Moreover,the maximum tensile stress of the electrode was found to be amplified by at least 1.8 times when the coating-dependent porosity is considered,indicating the necessity in the design of electrode structural integrity and optimization in service.The results of work are expected to provide important experimental data and model basis for the mechanical design of silicon composite electrodes upon usage.展开更多
The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic materials.While the most of the related publications mainly focused on the degradation rate ...The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic materials.While the most of the related publications mainly focused on the degradation rate of Mg-based materials,but rare to care about the changes of their mechanical properties during the immersion period,which can significantly affect their service performance.The link between residual strength and Mg degradation is not appreciated enough.In this work,a series media were constructed based on Hanks’solution,the effects of inorganic ions on the degradation rate and mechanical integrity of Mg-Zn-Y-Nd alloy were investigated.The results indicated that the degradation behavior of Mg alloy was mainly controlled by degradation products and there is no direct correspondence between the degradation rate change and mechanical integrity of Mg alloy.The relevant findings are beneficial for selecting the monitoring index in Mg corrosion tests and evaluating the service reliability of Mg alloys for biomedical applications.展开更多
Benefits of RE addition on Mg alloys strength and corrosion resistance are widely reported but their effects on biodegradability and biocompatibility are still of concern.This paper investigates the effect of RE addit...Benefits of RE addition on Mg alloys strength and corrosion resistance are widely reported but their effects on biodegradability and biocompatibility are still of concern.This paper investigates the effect of RE additions on biodegradability of Mg-Zn alloys under simulated physiological conditions.In this context,two commercial Mg-Zn-Zr-RE alloys,namely ZE41 and EZ33,with same RE addition but different concentrations are studied in Hank’s Balanced Salt Solution(HBSS)at 37℃and with pH of 7.4.Weight-loss,hydrogen evolution,real-time insitu drop test,electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization are deployed to study corrosion characteristics.The mechanical integrity of both alloys is assessed by mechanical testing post immersion.Furthermore,in vitro biocompatibility is evaluated by indirect cytotoxicity tests using NIH3T3 cells.Results reveal that although both alloys showed similar microstructure,size and distribution of precipitates played a significant role on its corrosion response.EIS and open circuit potential results show stable film formation on EZ33,while ZE41 showed passive layer formation followed by its deterioration,over the analyzed time period.Using real-time drop test,it was shown in ZE41 alloy that both T-phase and Zr-rich precipitates acted as micro cathodes,resulting in an unstable surface film.In EZ33,Zr-rich regions did not influence corrosion response,resulting in better corrosion resistance that was corroborated by post-immersion surface morphology investigations.The higher degradation observed in ZE41 alloy resulted in higher drop in flexural and tensile strength compared to EZ33 alloy.In addition,cytotoxicity tests on NIH3T3 cells revealed that cell viability of EZ33 increased with increasing incubation time,contrary to ZE41,owing to its lower biodegradation behavior and despite higher concentrations of REs.Present results show that an increase in RE concentration in EZ33,relative to ZE41,had a positive effect on corrosion rate that subsequently controlled alloy mechanical integrity and biocompatibility.展开更多
Magnesium alloys are promising as load bearing components.They are inevitably exposed to cyclic loading and corrosive environment in actual service,which can consequently result in corrosion fatigue failure and loss o...Magnesium alloys are promising as load bearing components.They are inevitably exposed to cyclic loading and corrosive environment in actual service,which can consequently result in corrosion fatigue failure and loss of mechanical integrity of the material.Therefore,in the present study,the corrosion behavior,corrosion fatigue performance and mechanical integrity of an extruded Mg4Zn0.2Sn(wt.%)alloy were thoroughly studied in two corrosive electrolytes.Strong localized corrosion occurred when the alloy was immersed in deionized water based sodium chloride(NaCl)solution.The poor corrosion resistance of the alloy resulted in a fast deterioration of the tensile properties after pre-exposure to salt spray and a poor fatigue resistance in deionized water based NaCl solution.In comparison,the active dissolution of the substrate was sufficiently suppressed in artificial tap water based NaCl solution due to the formation of highly protective corrosion product layers.This consequently conferred longer fatigue life on the alloy in the electrolyte.Our results emphasized the influence of corrosion on the fatigue behavior and tensile properties of magnesium alloys.展开更多
A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in p...A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using SEM-BSE-EBSD.The in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.展开更多
To develop durable bone healing strategies through improved control of bone repair,it is of critical importance to understand the mechanisms of bone mechanical integrity when in contact with biomaterials and implants....To develop durable bone healing strategies through improved control of bone repair,it is of critical importance to understand the mechanisms of bone mechanical integrity when in contact with biomaterials and implants.Bone mechanical integrity is defined here as the adaptation of structural properties of remodeled bone in regard to an applied mechanical loading.Accordingly,the authors present why future investigations in bone repair and regeneration should emphasize on the matrix surrounding the osteocytes.Osteocytes are mechanosensitive cells considered as the orchestrators of bone remodeling,which is the biological process involved in bone homeostasis.These bone cells are trapped in an interconnected porous network,the lacunocanalicular network,which is embedded in a bone mineralized extracellular matrix.As a consequence of an applied mechanical loading,the bone deformation results in the deformation of this lacunocanalicular network inducing a shift in interstitial fluid pressure and velocity,thus resulting in osteocyte stimulation.The material environment surrounding each osteocyte,the so called perilacunar and pericellular matrices properties,define its mechanosensitivity.While this mechanical stimulation pathway is well known,the laws used to predict bone remodeling are based on strains developing at a tissue scale,suggesting that these strains are related to the shift in fluid pressure and velocity at the lacunocanalicular scale.While this relationship has been validated through observation in healthy bone,the fluid behavior at the bone-implant interface is more complex.The presence of the implant modifies fluid behavior,so that for the same strain at a tissue scale,the shift in fluid pressure and velocity will be different than in a healthy bone tissue.In that context,new markers for bone mechanical integrity,considering fluid behavior,have to be defined.The viewpoint exposed by the authors indicates that the properties of the pericellular and the perilacunar matrices have to be systematically investigated and used as structural markers of fluid behavior in the course of bone biomaterial development.展开更多
Photovoltaic (PV) modules have emerged as an ideal technology of choice for <span>harvesting vastly available renewable energy resources. However, the effi</span>ciency <span>of PV modules remains si...Photovoltaic (PV) modules have emerged as an ideal technology of choice for <span>harvesting vastly available renewable energy resources. However, the effi</span>ciency <span>of PV modules remains significantly lower than that of other renewable</span> energy sources such as wind and hydro. One of the critical elements affecting a photovoltaic module’s efficiency is the variety of external climatic conditions under which it is installed. In this work, the effect of simulated snow loads was evaluated on the performance of PV modules with different <span>types of cells and numbers of busbars. According to ASTM-1830 and IEC-1215</span> standards, a load of 5400 Pa was applied to the surface of PV modules for 3 hours. An indigenously developed pneumatic airbag test setup was used for the uniform application of this load throughout the test, which was validated by load cell and pressure gauge. Electroluminescence (EL) imaging and solar flash tests were performed before and after the application of load to characterize the performance and effect of load on PV modules. Based on these tests, the maxi<span>mum power output, efficiency, fill factor and series resistance were deter</span>mined. The results show that polycrystalline modules are the most likely to withstand the snow loads as compared to monocrystalline PV modules. A maximum drop of 32.13% in the power output and a 17.6% increase in series resistance were observed in the modules having more cracks. These findings demonstrated the efficacy of the newly established test setup and the potential of snow loads for reducing the overall performance of PV module.展开更多
This study develops a three-dimensional automated detection framework(PitScan)that systematically evaluates the severity and phenomenology of pitting corrosion.This framework uses a python-based algorithm to analyse m...This study develops a three-dimensional automated detection framework(PitScan)that systematically evaluates the severity and phenomenology of pitting corrosion.This framework uses a python-based algorithm to analyse microcomputer-tomography scans(μCT)of cylindrical specimens undergoing corrosion.The approach systematically identifies several surface-based corrosion features,enabling full spatial characterisation of pitting parameters,including pit density,pit size,pit depth as well as pitting factor according to ASTM G46-94.Furthermore,it is used to evaluate pitting formation in tensile specimens of a Rare Earth Magnesium alloy undergoing corrosion,and relationships between key pitting parameters and mechanical performance are established.Results demonstrated that several of the parameters described in ASTM G46-94,including pit number,pit density and pitting factor,showed little correlation to mechanical performance.However,this study did identify that other parameters showed strong correlations with the ultimate tensile strength and these tended to be directly linked to the reduction of the cross-sectional area of the specimen.Specifically,our results indicate,that parameters directly linked to the loss of the cross-sectional area(e.g.minimum material width),are parameters that are most suited to provide an indication of a specimen’s mechanical performance.The automated detection framework developed in this study has the potential to provide a basis to standardise measurements of pitting corrosion across a range of metals and future prediction of mechanical strength over degradation time.展开更多
In the past two decades,various research works have been conducted in the field of flexible electronic devices(FEDs).Researchers have focused their efforts on solving the existing challenges in the electronic,electroc...In the past two decades,various research works have been conducted in the field of flexible electronic devices(FEDs).Researchers have focused their efforts on solving the existing challenges in the electronic,electrochemical,and mechanical behaviors of FEDs.The importance of flexible lithium-ion batteries(FLIBs)in the area of FEDs is evident;however,less attention has been paid to the mechanical behavior of FLIBs in comparison with the material and electrochemical characteristics.The present paper reviewed the research works in the FLIBs,focusing on their mechanical integrity and electrochemical performances.First,an introduction to FLIBs was presented,and the previous review papers published in this field were briefly introduced.Then,a detailed review of the available electrochemical and mechanical research works on FLIBs was presented.Moreover,the mechanical testing methods(tensile,compressive,indentation,fatigue,and adhesion)for the characterization of FLIBs’components,the research works on the simulation and modeling of the mechanical behavior of FLIBs,and a summary of the present situation and the future trend of research in this field were reviewed and presented.展开更多
The cyclic injection and production of fluids into and from underground gas storage(UGS)may lead to caprock failure,such as capillary sealing failure,hydraulic fracturing,shear failure,and fault slipping or dilation.T...The cyclic injection and production of fluids into and from underground gas storage(UGS)may lead to caprock failure,such as capillary sealing failure,hydraulic fracturing,shear failure,and fault slipping or dilation.The dynamic sealing capacity of a caprock-fault system is a critical constraint for safe operation,and is a key factor in determining the maximum operating pressure(MOP).This study proposed an efficient semi-analytical method for calculating changes in the in situ stress within the caprock.Next,the parameters of dynamic pore pressure,in situ stresses,and deformations obtained from reservoir simulations and geomechanical modeling were used for inputs for the analytical solution.Based on the calculated results,an experimental scheme for the coupled cyclic stress-permeability testing of caprock was designed.The stability analysis indicated that the caprock was not prone to fatigue shear failure under the current injection and production strategy,supported by the experimental results.The experimental results further reveal that the sealing capacity of caprock plugs may remain stable.This phenomenon is attributed to cyclic stress causing pore connectivity and microcrack initiation in certain plugs,while leading to pore compaction in others.A comparison between the dynamic pore pressure and the minimum principal stress suggests that the risk of tensile failure is extremely low.Furthermore,although the faults remain stable under the current injection and production strategies,the continuous increase in injection pressure may lead to an increased tendency for fault slip and dilation,which can cause fault slip ultimately.The MOPs corresponding to each failure mode were calculated.The minimum value of approximately 36.5 MPa at capillary sealing failure indicated that the gas breakthrough in the caprock occurred earlier than rock failure.Therefore,this minimumvalue can be used as the MOP for the target UGS.展开更多
The investigation explores the mechanical stress and electromagnetic performance for a wind-driven synchronous reluctance generator(SRG).The change in the mechanical stress due to the presence of centripetal force,win...The investigation explores the mechanical stress and electromagnetic performance for a wind-driven synchronous reluctance generator(SRG).The change in the mechanical stress due to the presence of centripetal force,wind speed,and rotor speed are evaluated for different thickness of tangential and radial ribs.Moreover,the variation in the electromagnetic feature such as the q−and d−axes flux,reactance ratio,inductance,torque and torque ripple are discussed for different thickness of tangential and radial ribs.Increasing both tangential and radial ribs thickness has an effect on the electromagnetic performance,but it is observed that effect is significantly more with the variation of tangential rib thickness.Similarly,the mechanical stress analysis for rotor design has been explored in this paper.It is observed that high concentration of peak stress on the rotor ribs,which limits the range of rotor speed.展开更多
With the increasing complexity of social public affairs,cross-departmental collaborative governance has become an important model of modern administrative management.However,conflicts of interest frequently occur duri...With the increasing complexity of social public affairs,cross-departmental collaborative governance has become an important model of modern administrative management.However,conflicts of interest frequently occur during the collaboration process,which are mainly reflected in resource allocation,goal differences,and power games.These conflicts are caused by factors such as cultural differences within departments,inconsistent performance evaluation systems,and personal interests of department members.To address these issues,it is necessary to design multi-level integration mechanisms,including establishing stable communication channels and unified goals and evaluation systems.Successful integration cases in various fields,such as food safety supervision,environmental protection,and urban transportation governance,show that effective integration mechanisms need to establish institutionalized communication carriers,form a consensus target system,and design guarantee measures with both incentives and constraints.Although current research has achieved certain results,there are still limitations,such as insufficient attention to underdeveloped regions,a lack of consideration of cultural factors,and a narrow focus on internal government collaboration.Future research can explore differentiated integration models,introduce third-party assessment institutions,and strengthen research on the participation mechanism of enterprises and social organizations.展开更多
Flower-infecting fungi have caused many economically important diseases in crop production.The fungal pathogen Ustilaginoidea virens infects developing rice florets,causing false smut disease,which leads to reduced gr...Flower-infecting fungi have caused many economically important diseases in crop production.The fungal pathogen Ustilaginoidea virens infects developing rice florets,causing false smut disease,which leads to reduced grain yield and quality,as well as contamination with mycotoxins that pose hazards to human health and food security.To ensure rice production,substantial efforts have been made to understand the interaction between rice and U.virens.In this review,we summarize the current understanding of rice resistance mechanisms to U.virens.We discuss the evaluation of false smut resistance,quantitative resistance loci,potential defense strategies of rice panicles,pathogen effector-driven identification of resistance-related genes,and engineering of false smut resistance.We conclude by proposing an integrated defense system that includes disease avoidance,immune response,metabolic adaptation,and the inhibition of susceptibility factors.Furthermore,we outline four critical stages of interaction between rice and U.virens that are essential for understanding and enhancing organ-specific rice resistance to false smut disease.展开更多
Globally,diabetic retinopathy(DR)is the primary cause of blindness,affecting millions of people worldwide.This widespread impact underscores the critical need for reliable and precise diagnostic techniques to ensure p...Globally,diabetic retinopathy(DR)is the primary cause of blindness,affecting millions of people worldwide.This widespread impact underscores the critical need for reliable and precise diagnostic techniques to ensure prompt diagnosis and effective treatment.Deep learning-based automated diagnosis for diabetic retinopathy can facilitate early detection and treatment.However,traditional deep learning models that focus on local views often learn feature representations that are less discriminative at the semantic level.On the other hand,models that focus on global semantic-level information might overlook critical,subtle local pathological features.To address this issue,we propose an adaptive multi-scale feature fusion network called(AMSFuse),which can adaptively combine multi-scale global and local features without compromising their individual representation.Specifically,our model incorporates global features for extracting high-level contextual information from retinal images.Concurrently,local features capture fine-grained details,such as microaneurysms,hemorrhages,and exudates,which are critical for DR diagnosis.These global and local features are adaptively fused using a fusion block,followed by an Integrated Attention Mechanism(IAM)that refines the fused features by emphasizing relevant regions,thereby enhancing classification accuracy for DR classification.Our model achieves 86.3%accuracy on the APTOS dataset and 96.6%RFMiD,both of which are comparable to state-of-the-art methods.展开更多
In this paper, we conduct research on the development of mechanical and electrical integration of system function principle and related technologies. Along with the rapid and continuous development of modem science an...In this paper, we conduct research on the development of mechanical and electrical integration of system function principle and related technologies. Along with the rapid and continuous development of modem science and technology, it ＇ s for the penetration and cross of different subjects great push, the more important is caused by technological revolution in the field of engineering and mechanical engineering field under the rapid development of computer technology and microelectronic technology and penetration to the mechanical and electrical integration, which is formed by the mechanical industry lead to trigger a particularly large changes in the mechanical industry management system and mode of production, product and technical structure, composition and function, thus result in industrial production from the previous mechanical electrification progressively electromechanical integration which lead the trend of the current technology.展开更多
Direct wafer bonding allows polished semiconductor wafers to be joined together without the use of a binder.It has a wide range of applications in integrated circuit fabrication,micro-electro-mechanical systems(MEMS)p...Direct wafer bonding allows polished semiconductor wafers to be joined together without the use of a binder.It has a wide range of applications in integrated circuit fabrication,micro-electro-mechanical systems(MEMS)packaging and multifunctional chip integration.Chip deflection and strain energy can be used to assess the bonding quality,and impurities have an important effect on the bonding quality.In this paper,a mathematical model and a finite element model of wafer bonding are established.The effects of different impurity distributions(Cluster,Complex,Face,Line)on the bonding quality of wafers are investigated,and the results show that the curvature and thickness of the wafer as well as the distribution of the impurity particles jointly determine the strain energy of the wafer under a certain pressure.Among them,the impurity particle surface distribution has the greatest influence on the wafer bonding quality.Finite element simulations verified the correctness of the proposed model.This work provides a theoretical basis for studying the effect of impurity distribution on wafer bonding performance.展开更多
Blast furnace (BF) ironmaking is the most typical “black box” process, and its complexity and uncertainty bring forth great challenges for furnace condition judgment and BF operation. Rich data resources for BF iron...Blast furnace (BF) ironmaking is the most typical “black box” process, and its complexity and uncertainty bring forth great challenges for furnace condition judgment and BF operation. Rich data resources for BF ironmaking are available, and the rapid development of data science and intelligent technology will provide an effective means to solve the uncertainty problem in the BF ironmaking process. This work focused on the application of artificial intelligence technology in BF ironmaking. The current intelligent BF ironmaking technology was summarized and analyzed from five aspects. These aspects include BF data management, the analyses of time delay and correlation, the prediction of BF key variables, the evaluation of BF status, and the multi-objective intelligent optimization of BF operations. Solutions and suggestions were offered for the problems in the current progress, and some outlooks for future prospects and technological breakthroughs were added. To effectively improve the BF data quality, we comprehensively considered the data problems and the characteristics of algorithms and selected the data processing method scientifically. For analyzing important BF characteristics, the effect of the delay was eliminated to ensure an accurate logical relationship between the BF parameters and economic indicators. As for BF parameter prediction and BF status evaluation,a BF intelligence model that integrates data information and process mechanism was built to effectively achieve the accurate prediction of BF key indexes and the scientific evaluation of BF status. During the optimization of BF parameters, low risk, low cost, and high return were used as the optimization criteria, and while pursuing the optimization effect, the feasibility and site operation cost were considered comprehensively.This work will help increase the process operator’s overall awareness and understanding of intelligent BF technology. Additionally, combining big data technology with the process will improve the practicality of data models in actual production and promote the application of intelligent technology in BF ironmaking.展开更多
The rate constants of the nucleophilic reactions between amines and benzhydrylium ions were calculated using first-principles theoretical methods. Solvation models including PCM, CPCM, and COSMORS, as well as differen...The rate constants of the nucleophilic reactions between amines and benzhydrylium ions were calculated using first-principles theoretical methods. Solvation models including PCM, CPCM, and COSMORS, as well as different types of atomic radii including UA0, UAKS, UAHF, Bondi, and UFF, and several single-point energy calculation methods （B3LYP, B3P86, B3PW91, BHANDH, PBEPBE, BMK, M06, MP2, and ONIOM method） were examined. By comparing the correlation between experimental rate constants and the calculated values, the ONIOM（CCSD（T）/6-311＋＋G（2df,2p）：B3LYP/6-311＋＋G（2df,2p））//B3LYP/6- 31G（d）/PCM/UFF） method was found to perform the best. This method was then employed to calculate the rate constants of the reactions between diverse amines and diarylcarbenium ions. The calculated rate constants for 65 reactions of amines with diarylcarbenium ions are in agreement with the experimental values, indicating that it is feasible to predict the rate constant of a reaction between an amine and a diarylcarbenium ion through ab initio calculation.展开更多
To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to ac...To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.展开更多
基金the Natural Science Foundation of Shanghai(Grant No.23ZR1421800)the National Natural Science Foundation of China(Grant Nos.12272213 and 11872235).
文摘Attributing to the noteworthy volume change of silicon active particles upon cycling,the porosity of the coated silicon composite electrode can vary significantly and therefore be expected to affect the apparent mechanical response of the composite electrode.However,direct experimental evidence is still lacking.By stripping the active layer from the current collector and performing quasi-static stretching tests,this work shows a direct correlation between the variation of tensile properties and related coating porosity of the silicon composite electrode during lithiation.Although silicon particles soften when lithiated,it is found that the increased particle volume can significantly lower the porosity of the coating,resulting in the densification of the silicon composite electrode and thus reducing the toughness of the silicon composite electrode and making the electrode more prone to lose its mechanical integrity under small strain in service.Based on finite element simulation and experimental data analysis,analytical expressions of equivalent modulus and strength of the porous silicon composite electrode were also constructed and are in good agreement with the experimental values.Moreover,the maximum tensile stress of the electrode was found to be amplified by at least 1.8 times when the coating-dependent porosity is considered,indicating the necessity in the design of electrode structural integrity and optimization in service.The results of work are expected to provide important experimental data and model basis for the mechanical design of silicon composite electrodes upon usage.
基金support from the Na-tional Key Research and Development Program of China(2021YFC2400703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251)support from Natural Science Foundation of Henan Provincial(222300420309).
文摘The degradation behavior of biodegradable Mg alloys has become a research hotspot in the fields about biodegradable metallic materials.While the most of the related publications mainly focused on the degradation rate of Mg-based materials,but rare to care about the changes of their mechanical properties during the immersion period,which can significantly affect their service performance.The link between residual strength and Mg degradation is not appreciated enough.In this work,a series media were constructed based on Hanks’solution,the effects of inorganic ions on the degradation rate and mechanical integrity of Mg-Zn-Y-Nd alloy were investigated.The results indicated that the degradation behavior of Mg alloy was mainly controlled by degradation products and there is no direct correspondence between the degradation rate change and mechanical integrity of Mg alloy.The relevant findings are beneficial for selecting the monitoring index in Mg corrosion tests and evaluating the service reliability of Mg alloys for biomedical applications.
基金NPRP grant#8-856-2-364 from the Qatar National Research Fund(a constituent member of the Qatar Foundation)。
文摘Benefits of RE addition on Mg alloys strength and corrosion resistance are widely reported but their effects on biodegradability and biocompatibility are still of concern.This paper investigates the effect of RE additions on biodegradability of Mg-Zn alloys under simulated physiological conditions.In this context,two commercial Mg-Zn-Zr-RE alloys,namely ZE41 and EZ33,with same RE addition but different concentrations are studied in Hank’s Balanced Salt Solution(HBSS)at 37℃and with pH of 7.4.Weight-loss,hydrogen evolution,real-time insitu drop test,electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization are deployed to study corrosion characteristics.The mechanical integrity of both alloys is assessed by mechanical testing post immersion.Furthermore,in vitro biocompatibility is evaluated by indirect cytotoxicity tests using NIH3T3 cells.Results reveal that although both alloys showed similar microstructure,size and distribution of precipitates played a significant role on its corrosion response.EIS and open circuit potential results show stable film formation on EZ33,while ZE41 showed passive layer formation followed by its deterioration,over the analyzed time period.Using real-time drop test,it was shown in ZE41 alloy that both T-phase and Zr-rich precipitates acted as micro cathodes,resulting in an unstable surface film.In EZ33,Zr-rich regions did not influence corrosion response,resulting in better corrosion resistance that was corroborated by post-immersion surface morphology investigations.The higher degradation observed in ZE41 alloy resulted in higher drop in flexural and tensile strength compared to EZ33 alloy.In addition,cytotoxicity tests on NIH3T3 cells revealed that cell viability of EZ33 increased with increasing incubation time,contrary to ZE41,owing to its lower biodegradation behavior and despite higher concentrations of REs.Present results show that an increase in RE concentration in EZ33,relative to ZE41,had a positive effect on corrosion rate that subsequently controlled alloy mechanical integrity and biocompatibility.
基金The author Pingli Jiang(CSC No.201606310043)would like to thank the financial support from China Scholarship Council(CSC)。
文摘Magnesium alloys are promising as load bearing components.They are inevitably exposed to cyclic loading and corrosive environment in actual service,which can consequently result in corrosion fatigue failure and loss of mechanical integrity of the material.Therefore,in the present study,the corrosion behavior,corrosion fatigue performance and mechanical integrity of an extruded Mg4Zn0.2Sn(wt.%)alloy were thoroughly studied in two corrosive electrolytes.Strong localized corrosion occurred when the alloy was immersed in deionized water based sodium chloride(NaCl)solution.The poor corrosion resistance of the alloy resulted in a fast deterioration of the tensile properties after pre-exposure to salt spray and a poor fatigue resistance in deionized water based NaCl solution.In comparison,the active dissolution of the substrate was sufficiently suppressed in artificial tap water based NaCl solution due to the formation of highly protective corrosion product layers.This consequently conferred longer fatigue life on the alloy in the electrolyte.Our results emphasized the influence of corrosion on the fatigue behavior and tensile properties of magnesium alloys.
基金CSIR-IMTECH laboratory for providing the technical support in biocompatibility testing。
文摘A novel PCL/HA/TiO_(2)hybrid coating on ZM21 Mg alloy substrate has been investigated for corrosion resistance, biocompatibility and mechanical integrity loss in terms of bending, compressive and tensile strength in physiological media. The prepared hybrid coating was dip coated over ZM21 from HA/TiO_(2)and PCL solutions followed by creating a microporous PCL layer by utilizing Non-solvent Induced Phase Separation(NIPS) technique. The electrochemical measurement and in-vitro degradation study in SBF after 28 days showed that the PCL/HA/TiO_(2) hybrid coating reduced H2 evolution rate, weight loss, and corrosion rate by 64, 116 and 118 times respectively, as compared to uncoated ZM21 samples. The surface studies carried out using SEM-EDX, FTIR and XRD revealed formation of highly stable 3d flower-like HA crystals with Ca/P ratio of 1.60 in the PCL micropores. This dense apatite growth effectively protected the PCL/HA/TiO_(2)hybrid coated samples to maintain the good mechanical integrity even after 28 days of immersion as compared to HA/TiO_(2)composite coated, As-polished(A/P) and As-machined(A/M) samples. The failure analysis of samples under mechanical loading were performed using SEM-BSE-EBSD.The in-vitro cellular viability of L929 fibroblast cells on PCL/HA/TiO_(2)hybrid coating was found 50.47% higher with respect to control group,whereas bacterial viability was supressed by 57.15 and 62.35% against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial models. The comprehensive assessment indicates PCL/HA/TiO_(2)hybrid coating as a suitable candidate to delay early degradation and mechanical integrity loss of Mg-based alloys for devising biodegradable orthopaedic implant.
文摘To develop durable bone healing strategies through improved control of bone repair,it is of critical importance to understand the mechanisms of bone mechanical integrity when in contact with biomaterials and implants.Bone mechanical integrity is defined here as the adaptation of structural properties of remodeled bone in regard to an applied mechanical loading.Accordingly,the authors present why future investigations in bone repair and regeneration should emphasize on the matrix surrounding the osteocytes.Osteocytes are mechanosensitive cells considered as the orchestrators of bone remodeling,which is the biological process involved in bone homeostasis.These bone cells are trapped in an interconnected porous network,the lacunocanalicular network,which is embedded in a bone mineralized extracellular matrix.As a consequence of an applied mechanical loading,the bone deformation results in the deformation of this lacunocanalicular network inducing a shift in interstitial fluid pressure and velocity,thus resulting in osteocyte stimulation.The material environment surrounding each osteocyte,the so called perilacunar and pericellular matrices properties,define its mechanosensitivity.While this mechanical stimulation pathway is well known,the laws used to predict bone remodeling are based on strains developing at a tissue scale,suggesting that these strains are related to the shift in fluid pressure and velocity at the lacunocanalicular scale.While this relationship has been validated through observation in healthy bone,the fluid behavior at the bone-implant interface is more complex.The presence of the implant modifies fluid behavior,so that for the same strain at a tissue scale,the shift in fluid pressure and velocity will be different than in a healthy bone tissue.In that context,new markers for bone mechanical integrity,considering fluid behavior,have to be defined.The viewpoint exposed by the authors indicates that the properties of the pericellular and the perilacunar matrices have to be systematically investigated and used as structural markers of fluid behavior in the course of bone biomaterial development.
文摘Photovoltaic (PV) modules have emerged as an ideal technology of choice for <span>harvesting vastly available renewable energy resources. However, the effi</span>ciency <span>of PV modules remains significantly lower than that of other renewable</span> energy sources such as wind and hydro. One of the critical elements affecting a photovoltaic module’s efficiency is the variety of external climatic conditions under which it is installed. In this work, the effect of simulated snow loads was evaluated on the performance of PV modules with different <span>types of cells and numbers of busbars. According to ASTM-1830 and IEC-1215</span> standards, a load of 5400 Pa was applied to the surface of PV modules for 3 hours. An indigenously developed pneumatic airbag test setup was used for the uniform application of this load throughout the test, which was validated by load cell and pressure gauge. Electroluminescence (EL) imaging and solar flash tests were performed before and after the application of load to characterize the performance and effect of load on PV modules. Based on these tests, the maxi<span>mum power output, efficiency, fill factor and series resistance were deter</span>mined. The results show that polycrystalline modules are the most likely to withstand the snow loads as compared to monocrystalline PV modules. A maximum drop of 32.13% in the power output and a 17.6% increase in series resistance were observed in the modules having more cracks. These findings demonstrated the efficacy of the newly established test setup and the potential of snow loads for reducing the overall performance of PV module.
基金funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 813869.
文摘This study develops a three-dimensional automated detection framework(PitScan)that systematically evaluates the severity and phenomenology of pitting corrosion.This framework uses a python-based algorithm to analyse microcomputer-tomography scans(μCT)of cylindrical specimens undergoing corrosion.The approach systematically identifies several surface-based corrosion features,enabling full spatial characterisation of pitting parameters,including pit density,pit size,pit depth as well as pitting factor according to ASTM G46-94.Furthermore,it is used to evaluate pitting formation in tensile specimens of a Rare Earth Magnesium alloy undergoing corrosion,and relationships between key pitting parameters and mechanical performance are established.Results demonstrated that several of the parameters described in ASTM G46-94,including pit number,pit density and pitting factor,showed little correlation to mechanical performance.However,this study did identify that other parameters showed strong correlations with the ultimate tensile strength and these tended to be directly linked to the reduction of the cross-sectional area of the specimen.Specifically,our results indicate,that parameters directly linked to the loss of the cross-sectional area(e.g.minimum material width),are parameters that are most suited to provide an indication of a specimen’s mechanical performance.The automated detection framework developed in this study has the potential to provide a basis to standardise measurements of pitting corrosion across a range of metals and future prediction of mechanical strength over degradation time.
基金Z.X.W.would like to thank International Partnership Program of Chinese Academy of Sciences(No.121D11KYSB20190080)M.M.S.would like to thank the Iran National Science Foundation(INSF)(No.98011735).
文摘In the past two decades,various research works have been conducted in the field of flexible electronic devices(FEDs).Researchers have focused their efforts on solving the existing challenges in the electronic,electrochemical,and mechanical behaviors of FEDs.The importance of flexible lithium-ion batteries(FLIBs)in the area of FEDs is evident;however,less attention has been paid to the mechanical behavior of FLIBs in comparison with the material and electrochemical characteristics.The present paper reviewed the research works in the FLIBs,focusing on their mechanical integrity and electrochemical performances.First,an introduction to FLIBs was presented,and the previous review papers published in this field were briefly introduced.Then,a detailed review of the available electrochemical and mechanical research works on FLIBs was presented.Moreover,the mechanical testing methods(tensile,compressive,indentation,fatigue,and adhesion)for the characterization of FLIBs’components,the research works on the simulation and modeling of the mechanical behavior of FLIBs,and a summary of the present situation and the future trend of research in this field were reviewed and presented.
基金supported by the National Natural Science Foundation of China(Grant No.42072166)Natural Science Foundation of Heilongjiang Province of China(Grant No.LH2020D004)Key R&D Program of Heilongjiang Province of China(Grant No.JD2023SJ26)。
文摘The cyclic injection and production of fluids into and from underground gas storage(UGS)may lead to caprock failure,such as capillary sealing failure,hydraulic fracturing,shear failure,and fault slipping or dilation.The dynamic sealing capacity of a caprock-fault system is a critical constraint for safe operation,and is a key factor in determining the maximum operating pressure(MOP).This study proposed an efficient semi-analytical method for calculating changes in the in situ stress within the caprock.Next,the parameters of dynamic pore pressure,in situ stresses,and deformations obtained from reservoir simulations and geomechanical modeling were used for inputs for the analytical solution.Based on the calculated results,an experimental scheme for the coupled cyclic stress-permeability testing of caprock was designed.The stability analysis indicated that the caprock was not prone to fatigue shear failure under the current injection and production strategy,supported by the experimental results.The experimental results further reveal that the sealing capacity of caprock plugs may remain stable.This phenomenon is attributed to cyclic stress causing pore connectivity and microcrack initiation in certain plugs,while leading to pore compaction in others.A comparison between the dynamic pore pressure and the minimum principal stress suggests that the risk of tensile failure is extremely low.Furthermore,although the faults remain stable under the current injection and production strategies,the continuous increase in injection pressure may lead to an increased tendency for fault slip and dilation,which can cause fault slip ultimately.The MOPs corresponding to each failure mode were calculated.The minimum value of approximately 36.5 MPa at capillary sealing failure indicated that the gas breakthrough in the caprock occurred earlier than rock failure.Therefore,this minimumvalue can be used as the MOP for the target UGS.
基金This work was sponsored by a Defense University from the National Defense of Ethiopia.
文摘The investigation explores the mechanical stress and electromagnetic performance for a wind-driven synchronous reluctance generator(SRG).The change in the mechanical stress due to the presence of centripetal force,wind speed,and rotor speed are evaluated for different thickness of tangential and radial ribs.Moreover,the variation in the electromagnetic feature such as the q−and d−axes flux,reactance ratio,inductance,torque and torque ripple are discussed for different thickness of tangential and radial ribs.Increasing both tangential and radial ribs thickness has an effect on the electromagnetic performance,but it is observed that effect is significantly more with the variation of tangential rib thickness.Similarly,the mechanical stress analysis for rotor design has been explored in this paper.It is observed that high concentration of peak stress on the rotor ribs,which limits the range of rotor speed.
文摘With the increasing complexity of social public affairs,cross-departmental collaborative governance has become an important model of modern administrative management.However,conflicts of interest frequently occur during the collaboration process,which are mainly reflected in resource allocation,goal differences,and power games.These conflicts are caused by factors such as cultural differences within departments,inconsistent performance evaluation systems,and personal interests of department members.To address these issues,it is necessary to design multi-level integration mechanisms,including establishing stable communication channels and unified goals and evaluation systems.Successful integration cases in various fields,such as food safety supervision,environmental protection,and urban transportation governance,show that effective integration mechanisms need to establish institutionalized communication carriers,form a consensus target system,and design guarantee measures with both incentives and constraints.Although current research has achieved certain results,there are still limitations,such as insufficient attention to underdeveloped regions,a lack of consideration of cultural factors,and a narrow focus on internal government collaboration.Future research can explore differentiated integration models,introduce third-party assessment institutions,and strengthen research on the participation mechanism of enterprises and social organizations.
基金supported by grants from the Sichuan Natural Science Foundation(2024NSFSC0335 and SCCXTD-2024-SD-4 to D.-Q.L.)the National Natural Science Foundation of China(32372490 and 32072503 to J.F.)。
文摘Flower-infecting fungi have caused many economically important diseases in crop production.The fungal pathogen Ustilaginoidea virens infects developing rice florets,causing false smut disease,which leads to reduced grain yield and quality,as well as contamination with mycotoxins that pose hazards to human health and food security.To ensure rice production,substantial efforts have been made to understand the interaction between rice and U.virens.In this review,we summarize the current understanding of rice resistance mechanisms to U.virens.We discuss the evaluation of false smut resistance,quantitative resistance loci,potential defense strategies of rice panicles,pathogen effector-driven identification of resistance-related genes,and engineering of false smut resistance.We conclude by proposing an integrated defense system that includes disease avoidance,immune response,metabolic adaptation,and the inhibition of susceptibility factors.Furthermore,we outline four critical stages of interaction between rice and U.virens that are essential for understanding and enhancing organ-specific rice resistance to false smut disease.
基金supported by the National Natural Science Foundation of China(No.62376287)the International Science and Technology Innovation Joint Base of Machine Vision and Medical Image Processing in Hunan Province(2021CB1013)the Natural Science Foundation of Hunan Province(Nos.2022JJ30762,2023JJ70016).
文摘Globally,diabetic retinopathy(DR)is the primary cause of blindness,affecting millions of people worldwide.This widespread impact underscores the critical need for reliable and precise diagnostic techniques to ensure prompt diagnosis and effective treatment.Deep learning-based automated diagnosis for diabetic retinopathy can facilitate early detection and treatment.However,traditional deep learning models that focus on local views often learn feature representations that are less discriminative at the semantic level.On the other hand,models that focus on global semantic-level information might overlook critical,subtle local pathological features.To address this issue,we propose an adaptive multi-scale feature fusion network called(AMSFuse),which can adaptively combine multi-scale global and local features without compromising their individual representation.Specifically,our model incorporates global features for extracting high-level contextual information from retinal images.Concurrently,local features capture fine-grained details,such as microaneurysms,hemorrhages,and exudates,which are critical for DR diagnosis.These global and local features are adaptively fused using a fusion block,followed by an Integrated Attention Mechanism(IAM)that refines the fused features by emphasizing relevant regions,thereby enhancing classification accuracy for DR classification.Our model achieves 86.3%accuracy on the APTOS dataset and 96.6%RFMiD,both of which are comparable to state-of-the-art methods.
文摘In this paper, we conduct research on the development of mechanical and electrical integration of system function principle and related technologies. Along with the rapid and continuous development of modem science and technology, it ＇ s for the penetration and cross of different subjects great push, the more important is caused by technological revolution in the field of engineering and mechanical engineering field under the rapid development of computer technology and microelectronic technology and penetration to the mechanical and electrical integration, which is formed by the mechanical industry lead to trigger a particularly large changes in the mechanical industry management system and mode of production, product and technical structure, composition and function, thus result in industrial production from the previous mechanical electrification progressively electromechanical integration which lead the trend of the current technology.
基金supported by the National Key R&D Program of China(No.2022YFB3207100)the Hubei Provincial Strategic Scientist Training Plan(No.2022EJD009)the Fundamental Research Funds for the Central Universities(No.2042023kf1041).
文摘Direct wafer bonding allows polished semiconductor wafers to be joined together without the use of a binder.It has a wide range of applications in integrated circuit fabrication,micro-electro-mechanical systems(MEMS)packaging and multifunctional chip integration.Chip deflection and strain energy can be used to assess the bonding quality,and impurities have an important effect on the bonding quality.In this paper,a mathematical model and a finite element model of wafer bonding are established.The effects of different impurity distributions(Cluster,Complex,Face,Line)on the bonding quality of wafers are investigated,and the results show that the curvature and thickness of the wafer as well as the distribution of the impurity particles jointly determine the strain energy of the wafer under a certain pressure.Among them,the impurity particle surface distribution has the greatest influence on the wafer bonding quality.Finite element simulations verified the correctness of the proposed model.This work provides a theoretical basis for studying the effect of impurity distribution on wafer bonding performance.
基金financially supported by the General Program of the National Natural Science Foundation of China(No.52274326)the Fundamental Research Funds for the Central Universities (Nos.2125018 and 2225008)China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202109)。
文摘Blast furnace (BF) ironmaking is the most typical “black box” process, and its complexity and uncertainty bring forth great challenges for furnace condition judgment and BF operation. Rich data resources for BF ironmaking are available, and the rapid development of data science and intelligent technology will provide an effective means to solve the uncertainty problem in the BF ironmaking process. This work focused on the application of artificial intelligence technology in BF ironmaking. The current intelligent BF ironmaking technology was summarized and analyzed from five aspects. These aspects include BF data management, the analyses of time delay and correlation, the prediction of BF key variables, the evaluation of BF status, and the multi-objective intelligent optimization of BF operations. Solutions and suggestions were offered for the problems in the current progress, and some outlooks for future prospects and technological breakthroughs were added. To effectively improve the BF data quality, we comprehensively considered the data problems and the characteristics of algorithms and selected the data processing method scientifically. For analyzing important BF characteristics, the effect of the delay was eliminated to ensure an accurate logical relationship between the BF parameters and economic indicators. As for BF parameter prediction and BF status evaluation,a BF intelligence model that integrates data information and process mechanism was built to effectively achieve the accurate prediction of BF key indexes and the scientific evaluation of BF status. During the optimization of BF parameters, low risk, low cost, and high return were used as the optimization criteria, and while pursuing the optimization effect, the feasibility and site operation cost were considered comprehensively.This work will help increase the process operator’s overall awareness and understanding of intelligent BF technology. Additionally, combining big data technology with the process will improve the practicality of data models in actual production and promote the application of intelligent technology in BF ironmaking.
文摘The rate constants of the nucleophilic reactions between amines and benzhydrylium ions were calculated using first-principles theoretical methods. Solvation models including PCM, CPCM, and COSMORS, as well as different types of atomic radii including UA0, UAKS, UAHF, Bondi, and UFF, and several single-point energy calculation methods （B3LYP, B3P86, B3PW91, BHANDH, PBEPBE, BMK, M06, MP2, and ONIOM method） were examined. By comparing the correlation between experimental rate constants and the calculated values, the ONIOM（CCSD（T）/6-311＋＋G（2df,2p）：B3LYP/6-311＋＋G（2df,2p））//B3LYP/6- 31G（d）/PCM/UFF） method was found to perform the best. This method was then employed to calculate the rate constants of the reactions between diverse amines and diarylcarbenium ions. The calculated rate constants for 65 reactions of amines with diarylcarbenium ions are in agreement with the experimental values, indicating that it is feasible to predict the rate constant of a reaction between an amine and a diarylcarbenium ion through ab initio calculation.
基金Supported by the National Natural Science Foundation of China Youth Fund Project(52005221)"the 13th Five-Year"National Key Research and Development Program:High-speed Planting Technology and Equipment Research and Development(2017YFD0700800)。
文摘To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.
