Forward extrusion experiments of as-cast AZ31 magnesium alloy were conducted at different temperatures and different extrusion ratios using the as-cast billets with and without homogenizing treatment.The mechanical pr...Forward extrusion experiments of as-cast AZ31 magnesium alloy were conducted at different temperatures and different extrusion ratios using the as-cast billets with and without homogenizing treatment.The mechanical properties of pre-and post-extrusion of the two kinds of billets were investigated.Experimental results show that the mechanical properties of post-extrusion of the two kinds of billets all are obviously improved compared with those of pre-extrusion.The elongation of post-extrusion using the billet with homogenizing is higher than that without homogenizing,but the tensile strength is lower than that without homogenizing.When the extrusion ratio increases,the elongation and tensile strength of post-extrusion of two kinds of billets all will increase obviously.When the extrusion temperature of billet without homogenizing increases,the tensile strength of post-extrusion will decrease obviously and the elongation of post-extrusion will change to a small extent.For the billet with homogenizing,the tensile strength of post-extrusion will decrease in some sort when extrusion temperature increases.展开更多
The microstructure of as-cast Ti-46AI-0.5W-0.5Si alloy exhibits significant microinhomogenetity due to the non-equilibrium solidification and low atom diffusion rate. In order to reduce the adverse effect of this micr...The microstructure of as-cast Ti-46AI-0.5W-0.5Si alloy exhibits significant microinhomogenetity due to the non-equilibrium solidification and low atom diffusion rate. In order to reduce the adverse effect of this microsegregation on plasticity, the microstructure evolution of the Ti-46AI-0.5W-0.5Si alloy homogenized at different temperatures from 1,200 ℃ to 1,320 ℃was investigated, and the optimized process of homogenizing treatment, i.e., annealing treated at 1,280 ℃ and held for 8 h, was determined. Microstructures of both the as-cast and heat treated alloys were observed by means of optical microscope and scanning electron microscopes. Tensile tests at room temperature were conducted on the homogenizing treated fully lamellar Ti-46AI-0.5W-0.5Si alloy with loading axis parallel to the lamellar interface. Results show that, at higher heat treatment temperatures, the W element diffuses sufficiently, the microstructure tends to be more homogeneous, and the profile of the silicide clusters becomes smooth. Heat treating conducted in the a＋y two phase region can keep the columnar grains and the original lamellar orientation within them. The microstructure of the alloy after heat treated in a＋y two phase region exhibits the coexisting morphology of coarse lamellar and thin lamellar. The homogenization process at 1,280℃ for 8 h can significantly reduce the microsegregation, and the elongation at room temperature can increase from 0.48% （as-cast） to 1.34%.展开更多
Homogeneous, high concentrated ceramic suspensions wi th low viscosity are the key controlling factors for the production of ceramic c omponents through colloidal processing. A well-dispersed suspension can be obta in...Homogeneous, high concentrated ceramic suspensions wi th low viscosity are the key controlling factors for the production of ceramic c omponents through colloidal processing. A well-dispersed suspension can be obta ined by choosing suitable dispersant, solvent, particle size distribution etc. B esides these factors, the homogenizing procedure is also a key step. In this paper, reaction sialon suspensions were prepared using 3-wt% KD1 as dis persant in organic media composed of 60-vol% methyletheylketone and 40-vol% et hanol. Different homogenizing procedures have been used and compared, including planetary milling, low energy ball milling and ultrasonic disaggregation. The ef fects of different homogenizing routes and mixing times on the rheology and stab ility of suspensions, and on the microstructure of slip casting green bodies, ha ve been studied. The varying dispersion efficiencies observed could be attribute d to differences in deagglomeration degrees achieved and in adsorption amount of dispersant onto the surface of reaction sialon powders.展开更多
To improve the homogeneity and rolling formability of as-cast AZ91 magnesium,the effects of pre-homogenizing treatment on microstructure evolution,deformation mechanism,mechanical properties and tensile fracture morph...To improve the homogeneity and rolling formability of as-cast AZ91 magnesium,the effects of pre-homogenizing treatment on microstructure evolution,deformation mechanism,mechanical properties and tensile fracture morphology of hot-rolled AZ91 magnesium alloy were studied.The results showed that the amount of coarseβ-Mg17Al12 phase decreases dramatically,being distributed along the grain boundaries as small strips after homogenizing.Twining plays a dominant role in the deformation mechanism of AZ91 alloys in the experimental condition,while dynamic recrystallization(DRX)considerably occurred in homogenized-rolled alloys,contributed to microstructure uniformity andβ-Mg17Al12 phase precipitated refinement.The tensile strength of homogenized-rolled AZ91 alloys increases dramatically with elongation declining slightly in contrast to homogenized alloys.The fracture surface of homogenized-rolled specimen exhibits more ductile fracture with the manifestation of a large amount of dimples distributing higher density in matrix,while the micro cracks are prone to initiate around the Mg/Mg17Al12 phase interface and grain boundaries owing to the fragile interface bonding of two phases.展开更多
Objective To quantitatively evaluate the contamination area and risk of a live pathogen during tissue homogenization by either ultrasonic processor or tissue disperser.Methods A recombinant Herpes Simplex Virus（rHSV...Objective To quantitatively evaluate the contamination area and risk of a live pathogen during tissue homogenization by either ultrasonic processor or tissue disperser.Methods A recombinant Herpes Simplex Virus（rHSV） containing GFP gene was used as the index virus,and fresh liver tissue from healthy mice was used as simulated specimen.After 10% liver homogenate was mixed with rHSV（100 TCID50/0.1 mL） in a 5 mL tube,the stability of rHSV in liver homogenate and influences of an ultrasonic processor and a tissue disperser on viral infectivity were determined by GFP expressions in cell cultures.The contaminating areas of live viruses during homogenization were evaluated by a cell culture-based sedimentary.The contamination radii were counted by measurement of the distance between the operator and the farthest GFP positive well.Results The infectivity of rHSV in 10% liver homogenate maintained almost unchanged after it was incubated at room temperature for 30 min.Treatment with an ultrasonic processor clearly dropped down the virus infectivity,while a disperser not.Obvious spills and slashes of live viruses were observed in processes of homogenization with those two apparatuses.The contamination radii are positively related with sample volume,output energy of operator and handling time.Conclusion Homogenizing infectious samples with an ultrasonic processor and a tissue disperser at commonly used conditions caused obvious spills and splashes of live viruses,which possesses high risk to induce Laboratory acquired infections（LAIs）.展开更多
Aqueous zinc-ion batteries(AZIBs)have emerged as a promising complement to lithium-ion batteries due to their inherent safety benefits.However,the cycle life of AZIBs is severely limited by the poor stability of zinc ...Aqueous zinc-ion batteries(AZIBs)have emerged as a promising complement to lithium-ion batteries due to their inherent safety benefits.However,the cycle life of AZIBs is severely limited by the poor stability of zinc anodes,manifested in uncontrolled dendritic growth and persistent side reactions,which hinder wider application.Herein,we report an ion-selective separator(UIO-66-4F/GF)achieved by in situ growth of a fluorine-functionalized metal-organic framework(UIO-66-4F)onto commercial glass fiber(GF).The synergistic mechanism,involving electrostatic repulsion between-F groups and SO_(4)^(2-)anions along with strong interactions between-F and Zn^(2+)cations,effectively restrict SO_(4)^(2-)migration,suppresses 2D Zn^(2+)diffusion across electrode interfaces,and enhances[Zn(H_(2)O)_(6)]^(2+)desolvation.Furthermore,the-F groups enable precise regulation of interfacial electric fields and Zn^(2+)concentration gradients,thereby homogenizing ion flux to realize dendrite-free Zn deposition.The UIO-66-4F separator achieves stable Zn||Zn cell operation for 1500 h at 1 mA cm^(-2)via oriented deposition and sustains long-term cycling over 1000 h at 1 mA cm^(-2),and delivers a Zn||Cu cell with 99.4%Coulombic efficiency.Moreover,the Zn|UIO-66-4F/GF|NH_(4)V_(4)O_(10) full cell represents an ultrastable cycling stability with a high capacity retention of 90%after 500 cycles at a current density of 1 A g^(-1).展开更多
Objective To optimize the extraction technology of the active component, rosmarinic acid, an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid, in perilla oil meal for the first time by a new homogenizing techn...Objective To optimize the extraction technology of the active component, rosmarinic acid, an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid, in perilla oil meal for the first time by a new homogenizing technology called smashing tissue extraction (STE). Methods Orthogonal design was used to optimize the extraction condition. The content of rosmarinic acid was quantified from the methanol crude extract with the help of HPLC. Results The optimization of STE process to get rosmarinic acid from the perilla oil meal was the ratio of liquid to solid material at 10:1 and the power of extraction at 150 V, extracting twice (2 min for each time). Conclusion STE could be applied to extracting the active ingredients from the oil meals due to its high extraction efficiency. This new homogenizing technology has advantages on saving extraction time, raising extraction efficiency, and maintaining the temperature sensitive constituents.展开更多
Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indice...Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease.展开更多
The influence of homogenization parameters on element segregation,dendritic structure,and the precipitate evolution in the GH3535-0.08wt%Y alloy was investigated.Additionally,some specific homogenization parameters we...The influence of homogenization parameters on element segregation,dendritic structure,and the precipitate evolution in the GH3535-0.08wt%Y alloy was investigated.Additionally,some specific homogenization parameters were maintained constant throughout the experiments.Results indicate that the heat treatment at 1150℃for 10 h is the optimal homogenization condition.Following this optimal treatment,dendrite structures and element segregation are eliminated.Furthermore,both SiC and Y_(5)Si_(3)precipitates in the as-cast alloy decrease significantly.Conversely,the homogenization at 1188℃induces overheating defects within the alloy.Although SiC and Y_(5)Si_(3)phases also decrease,some large M6C phases can still be observed,adversely affecting subsequent forging processes.展开更多
Biodiesel is a versatile energy source synthesized by trans esterifying various edible or nonedible oils using catalysts.It is preferable to diesel because of its higher flash points,reduced sulphur content,and biodeg...Biodiesel is a versatile energy source synthesized by trans esterifying various edible or nonedible oils using catalysts.It is preferable to diesel because of its higher flash points,reduced sulphur content,and biodegrad-ability.Biodiesel synthesis by esterification or transesterification methods involves conventional homogeneous or heterogeneous,enzymatic,supercritical,ultrasound,and microwave techniques.Since the operating condi-tions and mechanisms in each method differ,a comprehensive evaluation is necessary.This manuscript examines and covers a comprehensive summary of conventional heating,homogeneous and heterogeneous catalytic sys-tems.A review of enzymatic,supercritical,microwave,electrolysis,and ultrasound-assisted biodiesel synthesis techniques is also included.The comparative study of a microwave with a conventional system shows that it is superior to the latter due to inverse temperature gradient,high thermal efficiency,and reduction in activation energy,resulting in improved product purity and operating time.It performs better than slower enzymatic processes that involve product inhibition.It outperforms supercritical transesterification,which involves high operating conditions(temperature 200 to 300℃,pressure 20 to 30 MPa)and product deterioration.When compared to alternative approaches,microwave-aided transesterification significantly reduces response time and outperforms other methods.Techno-economic study and green chemistry principles are also favors in microwave-assisted biodiesel synthesis.Use of oleaginous microorganisms and microalgae as a feedstock,and process integration using valorization of waste glycerol,improved the sustainability of biodiesel synthesis.展开更多
Nucleation,which is the initial step of crystallization,critically governs the polymer crystallization behavior,influencing the crystallization temperature,kinetics,and morphology.However,the direct observation of the...Nucleation,which is the initial step of crystallization,critically governs the polymer crystallization behavior,influencing the crystallization temperature,kinetics,and morphology.However,the direct observation of the nucleation process in polymers remains elusive owing to spatial and temporal resolution limitations.This feature article summarizes the recent progress in understanding polymer nucleation within confined and interface-dominated environments,focusing on three representative systems:anodic aluminum oxide templates and nanocomposites containing nanoparticles or nanosheets.The interplay between finite size and interfacial effects has revealed some novel phenomena,such as homogeneous nucleation,surface nucleation,prefreezing,and supernucleation.展开更多
Urbanization has profoundly reshaped biodiversity,yet its impacts on community seasonal changes remain poorly understood.Here,we used citizen science data from 839 bird species in 37 cities and their corresponding rur...Urbanization has profoundly reshaped biodiversity,yet its impacts on community seasonal changes remain poorly understood.Here,we used citizen science data from 839 bird species in 37 cities and their corresponding rural areas in China to assess how urbanization alters seasonal changes in bird communities.We calculated Sørensen beta dissimilarity indices(β_(sor))between seasons to compare the seasonality of communities in urban and rural areas and decomposed these indices into turnover(β_(sim))and nestedness(β_(nes))components.We evaluated whether there are differences in the latitudinal clines in community seasonality between urban and rural areas,and explored whether environmental and socio-economic factors affect the urbanization-driven changes in community seasonality.Our results show that the overall seasonalβ_(sor)in urban communities was 16.2%higher than in rural areas,due to a 49.5%increase inβ_(nes)(urban:0.22±0.12 vs.rural:0.15±0.08),but there was no significant difference inβ_(sim).In rural areas,β_(sor)increased with latitude,butβ_(sor)showed no latitudinal trend in urban communities.Human population emerges as a key predictor of urbanization-driven changes in the species turnover and nestedness components,with larger cities showing lower species turnover but higher nestedness components.We conclude that urbanization alters the seasonality of bird communities through nestedness components,decouples the relationship between community seasonality and latitude,and concentrates its impacts in densely populated cities.Future research must employ long-term monitoring to track how urbanization changes bird communities in space and time.展开更多
Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenizatio...Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials.展开更多
Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community asse...Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community assembly in virgin and aging MP plastispheres across different habitats is poorly understood.This study aims to assess the variations in bacterial community assembly across different niches and habitats with an in situ ex-periment,in which constructed forest wetland(FW),natural lake wetland(LW),and lotus pond wetland(LP)were habitats,and plastispheres of virgin and aging low-density polyethylene(LDPE)MPs,as well as surround-ing wetland soils were niches.Significant niche-related differences in bacterial communities were observed,with lower diversity and enrichment of potential plastic-degrading bacteria in the plastisphere than in the soil bacterial communities.Furthermore,habitat-related differences exerted a more pronounced influence on the beta-diversity patterns of the bacterial communities.The linear regression analyses indicated that the local species pool con-tributed more to bacterial community assembly in the LW wetland,whereas the relative abundance of species was the primary factor in the LP wetland.The null model analysis indicated that plastisphere bacterial communi-ties were predominantly driven by the stochastic process,with a more deterministic assembly observed in the LP wetland and soil bacterial communities.Additionally,the primary ecological process shaping plastisphere com-munities shifted from drift in the virgin LDPE to homogenising dispersal in the aging LDPE.This study provides new insights into the fate and ecological impacts of MPs in wetlands,thereby facilitating the effective regulations of plastic pollution.展开更多
Understanding the microscopic time-dependent mechanical behavior of shale is critical for assessing macroscopic creep and engineering applications.Grid nanoindentation experiments and nanoindentation creep tests were ...Understanding the microscopic time-dependent mechanical behavior of shale is critical for assessing macroscopic creep and engineering applications.Grid nanoindentation experiments and nanoindentation creep tests were systematically conducted to investigate microscopic creep behaviors in shale.The indentation creep displacements and creep rates of the shale's soft,intermediate,and hard phases showed the same evolution patterns.The creep deformation was much higher in the soft phase than in the other two phases.However,the difference in the steady-state creep rates between the three mechanical phases was negligible.A linear relationship was observed between the microscopic contact creep modulus and the microscopic Young's modulus,hardness,creep displacement,and creep rate.The primary mechanism of microscopic creep in shale revealed by the creep strain rate sensitivity parameter was the extension and closure of microcracks.The differences in the microscopic creep parameters derived from the experimental data using the deconvolution methods and representative point methods were evaluated,and the applicability of the two methods was described.The performances of commonly used creep models to predict the microscopic creep behaviors were evaluated.The Burgers model provided the best performance in predicting the steady-state creep deformation and creep rate.The ability of the Mori-Tanaka and Voigt-Reuss-Hill models to derive macroscopic parameters from microscopic mechanical parameters was compared.Both methods provided macroscopic Young's modulus values close to the experimental values;however,neither could predict macroscopic creep parameters based on microscopic creep parameters.展开更多
In this paper,we study the asymptotic behavior of the micropolar fluid flow through a thin domain,assuming zero Dirichlet boundary condition on the top boundary,which is rapidly oscillating,and non-standard boundary c...In this paper,we study the asymptotic behavior of the micropolar fluid flow through a thin domain,assuming zero Dirichlet boundary condition on the top boundary,which is rapidly oscillating,and non-standard boundary conditions on the flat bottom.Assuming“Reynolds roughness regime”,in which the thickness of the domain is very small compared to the wavelength of the roughness(i.e.a very slight roughness),we rigorously derive a generalized Reynolds equation for pressure,clearly showing the roughness-induced effects.Moreover,we give expressions for the average velocity and microrotation.展开更多
In this paper,we first establish refined versions of the Bohr inequalities for the class of holomorphic functions from the unit ball BX of a complex Banach space X into ℂ.As applications,we will establish refined Bohr...In this paper,we first establish refined versions of the Bohr inequalities for the class of holomorphic functions from the unit ball BX of a complex Banach space X into ℂ.As applications,we will establish refined Bohr inequalities of functional type or of norm type for holomorphic mappings with lacunary series on the unit ball BX with values in higher dimensional spaces.Next,we obtain the Bohr-Rogosinski inequality for the class of holomorphic functions on BX.In addition,we establish an improved version of the Bohr inequality for holomorphic functions on BX.All the results are proved to be sharp.展开更多
In two-scale topology optimization,enhancing the connectivity between adjacent microstructures is crucial for achieving the collaborative optimization of micro-scale performance and macro-scale manufacturability.This ...In two-scale topology optimization,enhancing the connectivity between adjacent microstructures is crucial for achieving the collaborative optimization of micro-scale performance and macro-scale manufacturability.This paper proposes a two-scale concurrent topology optimization strategy aimed at improving the interface connection strength.This method employs a parametric approach to explicitly divide the micro-design domain into a“boundary connection region”and a“free design domain”at the initial stage of optimization.The boundary connection region is used to generate a connection layer that enhances the interface strength,while the free design domain is not constrained by this layer,thus fully exploiting the design potential of the material layout.During the optimization process,the solid isotropic material with penalization(SIMP)method is first used to optimize the material distribution in the free design domain,and filtering and projection techniques are employed to alleviate numerical instability and obtain a clear topological structure.Subsequently,the effective performance of the microstructure is calculated through homogenization and transferred to the macro-scale for global response analysis.Throughout the iterative process,the geometry of the connection layer remains unchanged,and only the free design domain is optimized,thereby achieving a balance between high performance and good manufacturability.The effectiveness of the proposed method is verified through numerical examples.展开更多
The goethite residue generated from zinc hydrometallurgy is classified as hazardous solid waste,produced in large quantities,and results in significant zinc loss.The study was conducted on removing iron from FeSO_(4)-...The goethite residue generated from zinc hydrometallurgy is classified as hazardous solid waste,produced in large quantities,and results in significant zinc loss.The study was conducted on removing iron from FeSO_(4)-ZnSO_(4) solution,employing seed-induced nucleation methods.Analysis of the iron removal rate,residue structure,morphology,and elemental composition involved ICP,XRD,FT-IR,and SEM.The existing state of zinc was investigated by combining step-by-step dissolution using hydrochloric acid.Concurrently,iron removal tests were extended to industrial solutions to assess the influence of seeds and solution pH on zinc loss and residue yield.The results revealed that seed addition increased the iron removal rate by 3%,elevated the residual iron content by 6.39%,and mitigated zinc loss by 29.55%in the simulated solution.Seed-induced nucleation prevented excessive nuclei formation,fostering crystal stable growth and high crystallinity.In addition,the zinc content of surface adsorption and crystal internal embedding in the residue was determined,and the zinc distribution on the surface was dense.In contrast,the total amount of zinc within the crystal was higher.The test results in the industrial solution demonstrated that the introduction of seeds expanded the pH range for goethite formation and growth,and the zinc loss per ton of iron removed was reduced by 50.91 kg(34.12%)and the iron residue reduced by 0.17 t(8.72%).展开更多
In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order hom...In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.展开更多
基金Projects(50605059,50735005)supported by the National Natural Science Foundation of ChinaProject(2009081012)supported by International Cooperation of Shanxi Province,ChinaProject(20090319ZX)supported by Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi Province,China
文摘Forward extrusion experiments of as-cast AZ31 magnesium alloy were conducted at different temperatures and different extrusion ratios using the as-cast billets with and without homogenizing treatment.The mechanical properties of pre-and post-extrusion of the two kinds of billets were investigated.Experimental results show that the mechanical properties of post-extrusion of the two kinds of billets all are obviously improved compared with those of pre-extrusion.The elongation of post-extrusion using the billet with homogenizing is higher than that without homogenizing,but the tensile strength is lower than that without homogenizing.When the extrusion ratio increases,the elongation and tensile strength of post-extrusion of two kinds of billets all will increase obviously.When the extrusion temperature of billet without homogenizing increases,the tensile strength of post-extrusion will decrease obviously and the elongation of post-extrusion will change to a small extent.For the billet with homogenizing,the tensile strength of post-extrusion will decrease in some sort when extrusion temperature increases.
基金supported by National Natural Science Foundation of China (Nos. 50975060, 50901025)the National Basic Research Program of China (2011CB610406)+2 种基金the China Postdoctoral Science Foundation (201104420, 20090450840)the Fundamental Research Funds for the Central Universities (HIT. BRET1. 2010008)Scientific and Technological Project in Heilongjiang Province (GZ09A206)
文摘The microstructure of as-cast Ti-46AI-0.5W-0.5Si alloy exhibits significant microinhomogenetity due to the non-equilibrium solidification and low atom diffusion rate. In order to reduce the adverse effect of this microsegregation on plasticity, the microstructure evolution of the Ti-46AI-0.5W-0.5Si alloy homogenized at different temperatures from 1,200 ℃ to 1,320 ℃was investigated, and the optimized process of homogenizing treatment, i.e., annealing treated at 1,280 ℃ and held for 8 h, was determined. Microstructures of both the as-cast and heat treated alloys were observed by means of optical microscope and scanning electron microscopes. Tensile tests at room temperature were conducted on the homogenizing treated fully lamellar Ti-46AI-0.5W-0.5Si alloy with loading axis parallel to the lamellar interface. Results show that, at higher heat treatment temperatures, the W element diffuses sufficiently, the microstructure tends to be more homogeneous, and the profile of the silicide clusters becomes smooth. Heat treating conducted in the a＋y two phase region can keep the columnar grains and the original lamellar orientation within them. The microstructure of the alloy after heat treated in a＋y two phase region exhibits the coexisting morphology of coarse lamellar and thin lamellar. The homogenization process at 1,280℃ for 8 h can significantly reduce the microsegregation, and the elongation at room temperature can increase from 0.48% （as-cast） to 1.34%.
文摘Homogeneous, high concentrated ceramic suspensions wi th low viscosity are the key controlling factors for the production of ceramic c omponents through colloidal processing. A well-dispersed suspension can be obta ined by choosing suitable dispersant, solvent, particle size distribution etc. B esides these factors, the homogenizing procedure is also a key step. In this paper, reaction sialon suspensions were prepared using 3-wt% KD1 as dis persant in organic media composed of 60-vol% methyletheylketone and 40-vol% et hanol. Different homogenizing procedures have been used and compared, including planetary milling, low energy ball milling and ultrasonic disaggregation. The ef fects of different homogenizing routes and mixing times on the rheology and stab ility of suspensions, and on the microstructure of slip casting green bodies, ha ve been studied. The varying dispersion efficiencies observed could be attribute d to differences in deagglomeration degrees achieved and in adsorption amount of dispersant onto the surface of reaction sialon powders.
基金the National Natural Science Foundation of China(Grant Nos.51175363 and 51474152)the Research Project Supported by the Shanxi Scholarship Council of China(Grant Nos.2014029)。
文摘To improve the homogeneity and rolling formability of as-cast AZ91 magnesium,the effects of pre-homogenizing treatment on microstructure evolution,deformation mechanism,mechanical properties and tensile fracture morphology of hot-rolled AZ91 magnesium alloy were studied.The results showed that the amount of coarseβ-Mg17Al12 phase decreases dramatically,being distributed along the grain boundaries as small strips after homogenizing.Twining plays a dominant role in the deformation mechanism of AZ91 alloys in the experimental condition,while dynamic recrystallization(DRX)considerably occurred in homogenized-rolled alloys,contributed to microstructure uniformity andβ-Mg17Al12 phase precipitated refinement.The tensile strength of homogenized-rolled AZ91 alloys increases dramatically with elongation declining slightly in contrast to homogenized alloys.The fracture surface of homogenized-rolled specimen exhibits more ductile fracture with the manifestation of a large amount of dimples distributing higher density in matrix,while the micro cracks are prone to initiate around the Mg/Mg17Al12 phase interface and grain boundaries owing to the fragile interface bonding of two phases.
基金supported by China Mega-Project for Infectious Disease (2009ZX10004-101,2009ZX10004-502)Health Sector Fund (200802021)SKLID Development Grant (2008SKLID102)
文摘Objective To quantitatively evaluate the contamination area and risk of a live pathogen during tissue homogenization by either ultrasonic processor or tissue disperser.Methods A recombinant Herpes Simplex Virus（rHSV） containing GFP gene was used as the index virus,and fresh liver tissue from healthy mice was used as simulated specimen.After 10% liver homogenate was mixed with rHSV（100 TCID50/0.1 mL） in a 5 mL tube,the stability of rHSV in liver homogenate and influences of an ultrasonic processor and a tissue disperser on viral infectivity were determined by GFP expressions in cell cultures.The contaminating areas of live viruses during homogenization were evaluated by a cell culture-based sedimentary.The contamination radii were counted by measurement of the distance between the operator and the farthest GFP positive well.Results The infectivity of rHSV in 10% liver homogenate maintained almost unchanged after it was incubated at room temperature for 30 min.Treatment with an ultrasonic processor clearly dropped down the virus infectivity,while a disperser not.Obvious spills and slashes of live viruses were observed in processes of homogenization with those two apparatuses.The contamination radii are positively related with sample volume,output energy of operator and handling time.Conclusion Homogenizing infectious samples with an ultrasonic processor and a tissue disperser at commonly used conditions caused obvious spills and splashes of live viruses,which possesses high risk to induce Laboratory acquired infections（LAIs）.
基金supported by the Natural Science Foundation of Hunan Province(Grant No.2024JJ6100)the Scientific Research Program of Hunan Education Department(Grant No.23B0676,22B0723)the Hengyang Normal University Science Foundation Project(Grant No.2023QD22,2024HSKFJJ019).
文摘Aqueous zinc-ion batteries(AZIBs)have emerged as a promising complement to lithium-ion batteries due to their inherent safety benefits.However,the cycle life of AZIBs is severely limited by the poor stability of zinc anodes,manifested in uncontrolled dendritic growth and persistent side reactions,which hinder wider application.Herein,we report an ion-selective separator(UIO-66-4F/GF)achieved by in situ growth of a fluorine-functionalized metal-organic framework(UIO-66-4F)onto commercial glass fiber(GF).The synergistic mechanism,involving electrostatic repulsion between-F groups and SO_(4)^(2-)anions along with strong interactions between-F and Zn^(2+)cations,effectively restrict SO_(4)^(2-)migration,suppresses 2D Zn^(2+)diffusion across electrode interfaces,and enhances[Zn(H_(2)O)_(6)]^(2+)desolvation.Furthermore,the-F groups enable precise regulation of interfacial electric fields and Zn^(2+)concentration gradients,thereby homogenizing ion flux to realize dendrite-free Zn deposition.The UIO-66-4F separator achieves stable Zn||Zn cell operation for 1500 h at 1 mA cm^(-2)via oriented deposition and sustains long-term cycling over 1000 h at 1 mA cm^(-2),and delivers a Zn||Cu cell with 99.4%Coulombic efficiency.Moreover,the Zn|UIO-66-4F/GF|NH_(4)V_(4)O_(10) full cell represents an ultrastable cycling stability with a high capacity retention of 90%after 500 cycles at a current density of 1 A g^(-1).
基金E&T Modern Center for Natural Products of Liaoning Province of China (2008402021)
文摘Objective To optimize the extraction technology of the active component, rosmarinic acid, an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid, in perilla oil meal for the first time by a new homogenizing technology called smashing tissue extraction (STE). Methods Orthogonal design was used to optimize the extraction condition. The content of rosmarinic acid was quantified from the methanol crude extract with the help of HPLC. Results The optimization of STE process to get rosmarinic acid from the perilla oil meal was the ratio of liquid to solid material at 10:1 and the power of extraction at 150 V, extracting twice (2 min for each time). Conclusion STE could be applied to extracting the active ingredients from the oil meals due to its high extraction efficiency. This new homogenizing technology has advantages on saving extraction time, raising extraction efficiency, and maintaining the temperature sensitive constituents.
基金supported by the National Natural Science Foundation of China,No.82071909(to GF)the Natural Science Foundation of Liaoning Province,No.2023-MS-07(to HL)。
文摘Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease.
基金National Natural Science Foundation of China(51801227,52071331)。
文摘The influence of homogenization parameters on element segregation,dendritic structure,and the precipitate evolution in the GH3535-0.08wt%Y alloy was investigated.Additionally,some specific homogenization parameters were maintained constant throughout the experiments.Results indicate that the heat treatment at 1150℃for 10 h is the optimal homogenization condition.Following this optimal treatment,dendrite structures and element segregation are eliminated.Furthermore,both SiC and Y_(5)Si_(3)precipitates in the as-cast alloy decrease significantly.Conversely,the homogenization at 1188℃induces overheating defects within the alloy.Although SiC and Y_(5)Si_(3)phases also decrease,some large M6C phases can still be observed,adversely affecting subsequent forging processes.
文摘Biodiesel is a versatile energy source synthesized by trans esterifying various edible or nonedible oils using catalysts.It is preferable to diesel because of its higher flash points,reduced sulphur content,and biodegrad-ability.Biodiesel synthesis by esterification or transesterification methods involves conventional homogeneous or heterogeneous,enzymatic,supercritical,ultrasound,and microwave techniques.Since the operating condi-tions and mechanisms in each method differ,a comprehensive evaluation is necessary.This manuscript examines and covers a comprehensive summary of conventional heating,homogeneous and heterogeneous catalytic sys-tems.A review of enzymatic,supercritical,microwave,electrolysis,and ultrasound-assisted biodiesel synthesis techniques is also included.The comparative study of a microwave with a conventional system shows that it is superior to the latter due to inverse temperature gradient,high thermal efficiency,and reduction in activation energy,resulting in improved product purity and operating time.It performs better than slower enzymatic processes that involve product inhibition.It outperforms supercritical transesterification,which involves high operating conditions(temperature 200 to 300℃,pressure 20 to 30 MPa)and product deterioration.When compared to alternative approaches,microwave-aided transesterification significantly reduces response time and outperforms other methods.Techno-economic study and green chemistry principles are also favors in microwave-assisted biodiesel synthesis.Use of oleaginous microorganisms and microalgae as a feedstock,and process integration using valorization of waste glycerol,improved the sustainability of biodiesel synthesis.
基金financially supported by the National Natural Science Foundation of China(Nos.21873109 and 21922308)。
文摘Nucleation,which is the initial step of crystallization,critically governs the polymer crystallization behavior,influencing the crystallization temperature,kinetics,and morphology.However,the direct observation of the nucleation process in polymers remains elusive owing to spatial and temporal resolution limitations.This feature article summarizes the recent progress in understanding polymer nucleation within confined and interface-dominated environments,focusing on three representative systems:anodic aluminum oxide templates and nanocomposites containing nanoparticles or nanosheets.The interplay between finite size and interfacial effects has revealed some novel phenomena,such as homogeneous nucleation,surface nucleation,prefreezing,and supernucleation.
基金supported by the National Natural Science Foundation of China(Grant No.32271733)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011045)。
文摘Urbanization has profoundly reshaped biodiversity,yet its impacts on community seasonal changes remain poorly understood.Here,we used citizen science data from 839 bird species in 37 cities and their corresponding rural areas in China to assess how urbanization alters seasonal changes in bird communities.We calculated Sørensen beta dissimilarity indices(β_(sor))between seasons to compare the seasonality of communities in urban and rural areas and decomposed these indices into turnover(β_(sim))and nestedness(β_(nes))components.We evaluated whether there are differences in the latitudinal clines in community seasonality between urban and rural areas,and explored whether environmental and socio-economic factors affect the urbanization-driven changes in community seasonality.Our results show that the overall seasonalβ_(sor)in urban communities was 16.2%higher than in rural areas,due to a 49.5%increase inβ_(nes)(urban:0.22±0.12 vs.rural:0.15±0.08),but there was no significant difference inβ_(sim).In rural areas,β_(sor)increased with latitude,butβ_(sor)showed no latitudinal trend in urban communities.Human population emerges as a key predictor of urbanization-driven changes in the species turnover and nestedness components,with larger cities showing lower species turnover but higher nestedness components.We conclude that urbanization alters the seasonality of bird communities through nestedness components,decouples the relationship between community seasonality and latitude,and concentrates its impacts in densely populated cities.Future research must employ long-term monitoring to track how urbanization changes bird communities in space and time.
基金Project supported by the National Natural Science Foundation of China(No.12472077)the supports from Shanghai Gaofeng Project for University Academic Program Development,Fundamental Research Funds for the Central Universities(No.22120240353).
文摘Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials.
基金supported by Shanghai Municipal Natural Science Foundation,China(No.21ZR1446800)the National Natural Science Foundation of China(No.41877425)the Fundamental Research Funds for the Central Universities(No.226-2024-00052)。
文摘Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community assembly in virgin and aging MP plastispheres across different habitats is poorly understood.This study aims to assess the variations in bacterial community assembly across different niches and habitats with an in situ ex-periment,in which constructed forest wetland(FW),natural lake wetland(LW),and lotus pond wetland(LP)were habitats,and plastispheres of virgin and aging low-density polyethylene(LDPE)MPs,as well as surround-ing wetland soils were niches.Significant niche-related differences in bacterial communities were observed,with lower diversity and enrichment of potential plastic-degrading bacteria in the plastisphere than in the soil bacterial communities.Furthermore,habitat-related differences exerted a more pronounced influence on the beta-diversity patterns of the bacterial communities.The linear regression analyses indicated that the local species pool con-tributed more to bacterial community assembly in the LW wetland,whereas the relative abundance of species was the primary factor in the LP wetland.The null model analysis indicated that plastisphere bacterial communi-ties were predominantly driven by the stochastic process,with a more deterministic assembly observed in the LP wetland and soil bacterial communities.Additionally,the primary ecological process shaping plastisphere com-munities shifted from drift in the virgin LDPE to homogenising dispersal in the aging LDPE.This study provides new insights into the fate and ecological impacts of MPs in wetlands,thereby facilitating the effective regulations of plastic pollution.
基金National Natural Science Foundation of China,Grant/Award Numbers:12172230,52422403,U22A20166,52304097National Science and Technology Major Project,Grant/Award Number:2024ZD1003903+2 种基金Department of Science and Technology of Guangdong Province,Grant/Award Number:2019ZT08G315Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2023A1515012654,2022A1515110030Young Elite Scientists Sponsorship Program by CAST,Grant/Award Number:2023QNRC001。
文摘Understanding the microscopic time-dependent mechanical behavior of shale is critical for assessing macroscopic creep and engineering applications.Grid nanoindentation experiments and nanoindentation creep tests were systematically conducted to investigate microscopic creep behaviors in shale.The indentation creep displacements and creep rates of the shale's soft,intermediate,and hard phases showed the same evolution patterns.The creep deformation was much higher in the soft phase than in the other two phases.However,the difference in the steady-state creep rates between the three mechanical phases was negligible.A linear relationship was observed between the microscopic contact creep modulus and the microscopic Young's modulus,hardness,creep displacement,and creep rate.The primary mechanism of microscopic creep in shale revealed by the creep strain rate sensitivity parameter was the extension and closure of microcracks.The differences in the microscopic creep parameters derived from the experimental data using the deconvolution methods and representative point methods were evaluated,and the applicability of the two methods was described.The performances of commonly used creep models to predict the microscopic creep behaviors were evaluated.The Burgers model provided the best performance in predicting the steady-state creep deformation and creep rate.The ability of the Mori-Tanaka and Voigt-Reuss-Hill models to derive macroscopic parameters from microscopic mechanical parameters was compared.Both methods provided macroscopic Young's modulus values close to the experimental values;however,neither could predict macroscopic creep parameters based on microscopic creep parameters.
文摘In this paper,we study the asymptotic behavior of the micropolar fluid flow through a thin domain,assuming zero Dirichlet boundary condition on the top boundary,which is rapidly oscillating,and non-standard boundary conditions on the flat bottom.Assuming“Reynolds roughness regime”,in which the thickness of the domain is very small compared to the wavelength of the roughness(i.e.a very slight roughness),we rigorously derive a generalized Reynolds equation for pressure,clearly showing the roughness-induced effects.Moreover,we give expressions for the average velocity and microrotation.
基金supported by the SERB,SUR/2022/002244,Govt.India and the second author was supported by the UGC-JRF(NTA Ref.No.:201610135853)New Delhi,India,and the third author was partially supported by the JSPS KAKENHI(JP22K03363).
文摘In this paper,we first establish refined versions of the Bohr inequalities for the class of holomorphic functions from the unit ball BX of a complex Banach space X into ℂ.As applications,we will establish refined Bohr inequalities of functional type or of norm type for holomorphic mappings with lacunary series on the unit ball BX with values in higher dimensional spaces.Next,we obtain the Bohr-Rogosinski inequality for the class of holomorphic functions on BX.In addition,we establish an improved version of the Bohr inequality for holomorphic functions on BX.All the results are proved to be sharp.
基金supported by the Science and Technology Research Project of Henan Province(242102241055)the Industry-University-Research Collaborative Innovation Base on Automobile Lightweight of“Science and Technology Innovation in Central Plains”(2024KCZY315)the Opening Fund of State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment(GZ2024A03-ZZU).
文摘In two-scale topology optimization,enhancing the connectivity between adjacent microstructures is crucial for achieving the collaborative optimization of micro-scale performance and macro-scale manufacturability.This paper proposes a two-scale concurrent topology optimization strategy aimed at improving the interface connection strength.This method employs a parametric approach to explicitly divide the micro-design domain into a“boundary connection region”and a“free design domain”at the initial stage of optimization.The boundary connection region is used to generate a connection layer that enhances the interface strength,while the free design domain is not constrained by this layer,thus fully exploiting the design potential of the material layout.During the optimization process,the solid isotropic material with penalization(SIMP)method is first used to optimize the material distribution in the free design domain,and filtering and projection techniques are employed to alleviate numerical instability and obtain a clear topological structure.Subsequently,the effective performance of the microstructure is calculated through homogenization and transferred to the macro-scale for global response analysis.Throughout the iterative process,the geometry of the connection layer remains unchanged,and only the free design domain is optimized,thereby achieving a balance between high performance and good manufacturability.The effectiveness of the proposed method is verified through numerical examples.
基金Project(2018YFC1900403) supported by the National Key Research and Development Program of ChinaProject(CX20210197) supported by the Postgraduate Scientific Research Innovation Project of Hunan Province,China+1 种基金Project(202206370103) supported by the China Scholarship CouncilProject(2021zzts0115) supported by the Fundamental Research Funds for the Central Universities,China。
文摘The goethite residue generated from zinc hydrometallurgy is classified as hazardous solid waste,produced in large quantities,and results in significant zinc loss.The study was conducted on removing iron from FeSO_(4)-ZnSO_(4) solution,employing seed-induced nucleation methods.Analysis of the iron removal rate,residue structure,morphology,and elemental composition involved ICP,XRD,FT-IR,and SEM.The existing state of zinc was investigated by combining step-by-step dissolution using hydrochloric acid.Concurrently,iron removal tests were extended to industrial solutions to assess the influence of seeds and solution pH on zinc loss and residue yield.The results revealed that seed addition increased the iron removal rate by 3%,elevated the residual iron content by 6.39%,and mitigated zinc loss by 29.55%in the simulated solution.Seed-induced nucleation prevented excessive nuclei formation,fostering crystal stable growth and high crystallinity.In addition,the zinc content of surface adsorption and crystal internal embedding in the residue was determined,and the zinc distribution on the surface was dense.In contrast,the total amount of zinc within the crystal was higher.The test results in the industrial solution demonstrated that the introduction of seeds expanded the pH range for goethite formation and growth,and the zinc loss per ton of iron removed was reduced by 50.91 kg(34.12%)and the iron residue reduced by 0.17 t(8.72%).
基金support by the National Key R&D Program of China(Grant No.2023YFA1008901)the National Natural Science Foundation of China(Grant Nos.11988102,12172009)is gratefully acknowledged.
文摘In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.
