It is known that “Fish Oil” is the raw material that has lot of benefits for health, because fish oil consists of several necessary unsaturated fatty acids, particularly Omega-3 and Docosahexanoic acid (DHA). Omega-...It is known that “Fish Oil” is the raw material that has lot of benefits for health, because fish oil consists of several necessary unsaturated fatty acids, particularly Omega-3 and Docosahexanoic acid (DHA). Omega-3 can decrease triglyceride level, and then it can increase HDL cholesterol level. In addition, DHA can support brain cell synthesis and also nervous system for human.展开更多
In conventional parabolic trough collectors(PTCs),sunlight is concentrated at the bottom of the absorber tube,resulting in a significant circumferential temperature gradient across the absorber tube,heat loss and ther...In conventional parabolic trough collectors(PTCs),sunlight is concentrated at the bottom of the absorber tube,resulting in a significant circumferential temperature gradient across the absorber tube,heat loss and thermal deformation,which affects the safety and thermal performance of PTCs.In this study,a new receiver with homogenizer and spiral(RHS) is proposed,achieving the optical and thermal synergy to ameliorate the thermal deformation of the absorber tube and enhance thermal efficiency.A plane structure homogenizer is designed to improve uniformity of the concentrated solar flux of absorber tube through second reflection.In combination with the spiral,it improves the optical-thermal efficiency of the PTC by enhancing heat exchange between the fluid and the backlight side of the absorber tube.The performance of the collector is numerically studied by building a three-dimensional coupled light-thermal-structure model.The results show that the thermal deformation of the RHS is reduced by more than 96% and the optical-thermal efficiency is improved by 1.2%-0.63% compared with conventional receivers(CRs) under the same inlet temperature conditions.The proposed receiver is validated to be effective in reducing thermal deformation and improving optical-thermal efficiency.展开更多
A Laser Doppler Anemometer (LDA) is used to measure and study the flow field in the working chamber of a homogenizer. Flow Patterns, distributions of mean and fluctuating velocities, shear rates are obtained in detail...A Laser Doppler Anemometer (LDA) is used to measure and study the flow field in the working chamber of a homogenizer. Flow Patterns, distributions of mean and fluctuating velocities, shear rates are obtained in details. The characteristics of the flow field and the basic principles of homogenizing are presented. These results are very helpful for the improvement of fluid homogenizers.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
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
This paper was to investigate basic properties of micro/ nano fibrils from poplar with a high pressure homogenizer. Their basic properties were tested by laser particle size analyzer, scanning electron microscopy (SEM...This paper was to investigate basic properties of micro/ nano fibrils from poplar with a high pressure homogenizer. Their basic properties were tested by laser particle size analyzer, scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The test results showed that if the fiber slurry moved from 20 to 40 circulations through the homogenizer, for 10% of the micro/nano fibrils, the particle size was reduced from 1.2 μm to 160 nm and its surface area per unit volume was increased from 1.63 × 104 to 8.38 × 104 cm2/cm3 when the concentration of fiber in suspension was 0.5% and the homogenization pressure was 800 bar. A distribution in the dimensions of the cellulose whiskers was seen by scanning electron microscopy. It was proved by X-ray diffractometer that the crystal degree of the micro/nano fibrils had a small change during the conversion process.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
As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal...As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.展开更多
Porous organic cages(POCs)with permanent porosity and excellent host–vip property hold great potentials in regulating ion transport behavior,yet their feasibility as solid-state electrolytes has never been testifie...Porous organic cages(POCs)with permanent porosity and excellent host–vip property hold great potentials in regulating ion transport behavior,yet their feasibility as solid-state electrolytes has never been testified in a practical battery.Herein,we design and fabricate a quasi-solid-state electrolyte(QSSE)based on a POC to enable the stable operation of Li-metal batteries(LMBs).Benefiting from the ordered channels and cavity-induced anion-trapping effect of POC,the resulting POC-based QSSE exhibits a high Li+transference number of 0.67 and a high ionic conductivity of 1.25×10^(−4) S cm^(−1) with a low activation energy of 0.17 eV.These allow for homogeneous Li deposition and highly reversible Li plating/stripping for over 2000 h.As a proof of concept,the LMB assembled with POC-based QSSE demonstrates extremely stable cycling performance with 85%capacity retention after 1000 cycles.Therefore,our work demonstrates the practical applicability of POC as SSEs for LMBs and could be extended to other energy-storage systems,such as Na and K batteries.展开更多
Social interaction with peer pressure is widely studied in social network analysis.Game theory can be utilized to model dynamic social interaction,and one class of game network models assumes that people’s decision p...Social interaction with peer pressure is widely studied in social network analysis.Game theory can be utilized to model dynamic social interaction,and one class of game network models assumes that people’s decision payoff functions hinge on individual covariates and the choices of their friends.However,peer pressure would be misidentified and induce a non-negligible bias when incomplete covariates are involved in the game model.For this reason,we develop a generalized constant peer effects model based on homogeneity structure in dynamic social networks.The new model can effectively avoid bias through homogeneity pursuit and can be applied to a wider range of scenarios.To estimate peer pressure in the model,we first present two algorithms based on the initialize expand merge method and the polynomial-time twostage method to estimate homogeneity parameters.Then we apply the nested pseudo-likelihood method and obtain consistent estimators of peer pressure.Simulation evaluations show that our proposed methodology can achieve desirable and effective results in terms of the community misclassification rate and parameter estimation error.We also illustrate the advantages of our model in the empirical analysis when compared with a benchmark model.展开更多
Hot compression tests for GH4706 alloy were performed at a true strain of 1.2 within the temperature range of 950-1150℃ and the strain rate range of 0.001-1 s^(-1).The optimal hot deformation temperature and strain r...Hot compression tests for GH4706 alloy were performed at a true strain of 1.2 within the temperature range of 950-1150℃ and the strain rate range of 0.001-1 s^(-1).The optimal hot deformation temperature and strain rate range were determined using nephogram maps of dynamic recrystallization fraction,average grain size,and grain distribution standard deviation.Processing maps at true strains from 0.4 to 0.9 were generated based on flow stress curves to identify the strain corresponding to optimal microstructure homogenization efficiency at various temperatures and strain rates.Results show that within the optimal parameter range,under the conditions of 1150℃ and 0.01 s^(-1),the true strain of about 0.6 results in the optimal microstructure homogenization efficiency.The grain orientation spread maps obtained from the experiment also confirms this conclusion.This study provides an effective method for microstructure homogenization control of GH4706 alloy and an effective reference for the minimum strain threshold of the local part of the forging in engineering.展开更多
To achieve efficient catalytic hydrogenation of CO_(2)to formate,we employed a transmetallation strategy to develop three novel iridium(Ⅰ)complexes,which feature N‑heterocyclic carbene‑nitrogen‑phosphine ligands(CNP)...To achieve efficient catalytic hydrogenation of CO_(2)to formate,we employed a transmetallation strategy to develop three novel iridium(Ⅰ)complexes,which feature N‑heterocyclic carbene‑nitrogen‑phosphine ligands(CNP)and a 1,5‑cyclooctadiene(cod)molecule:[Ir(cod)(κ^(3)‑CN^(im)P)]Cl(1⁃Cl),[Ir(cod)(κ^(3)‑CN^(im)P)]PF6(1⁃PF_(6)),and[Ir(cod)(κ^(3)‑CNHP)]Cl(2).The^(1)H NMR spectra,^(31)P NMR spectra,and high‑resolution mass spectra verify the successful synthesis of these three Ir(Ⅰ)‑CNP complexes.Furthermore,single‑crystal X‑ray diffraction analysis confirms the coordination geometry of 1⁃PF_(6).The strong Ir—C(NHC)bond suggests that the carbene carbon plays an enhanced anchoring role to iridium due to its strongσ‑donating ability,which helps stabilize the active metal species during CO_(2)hydrogenation.As a result,the Ir(Ⅰ)‑CNP complex exhibits remarkable activity and long catalytic lifetime for the hydrogenation of CO_(2)to formate,reaching a turnover number(TON)of 1.16×10^(6)after 150 h at a high temperature of 170℃,which was a relatively high value among all the Ir complexes.CCDC:2384071,1⁃PF_(6).展开更多
Photoredox catalysis has made significant advances in stateof-the-art chemical synthesis,drawing energy from inexhaustible light and enabling various organic transformations to occur under mild reaction conditions.Ove...Photoredox catalysis has made significant advances in stateof-the-art chemical synthesis,drawing energy from inexhaustible light and enabling various organic transformations to occur under mild reaction conditions.Over the past few years,a variety of homogeneous and heterogeneous photocatalysts have been applied in the photoredox catalysis.Heterogeneous photoredox catalysis offers advantages such as easy separation and superior recyclability compared to homogeneous counterparts,although homogenous catalysts are usually associated with higher activities and selectivity.From a practical perspective,an optimal photoredox catalytic system would integrate the advantages of both homogeneous and heterogeneous cases.展开更多
1.Introduction Al-Zn-Mg-Cu alloy is a typical age-hardening aluminum alloy,its strength and toughness are significantly influenced by precipita-tion behavior.The nucleation mechanisms of precipitates in this alloy are...1.Introduction Al-Zn-Mg-Cu alloy is a typical age-hardening aluminum alloy,its strength and toughness are significantly influenced by precipita-tion behavior.The nucleation mechanisms of precipitates in this alloy are generally categorized into homogeneous and heterogeneous nucleation.Homogeneous nucleation relies on structural and energy fluctuations within the solution to generate the driving force necessary for direct nucleation.展开更多
The acoustic wave propagation in gas-saturated double-porosity materials composed of a microporous matrix and mesopores with arrays of plate-type resonators is investigated.A macroscopic description,established with t...The acoustic wave propagation in gas-saturated double-porosity materials composed of a microporous matrix and mesopores with arrays of plate-type resonators is investigated.A macroscopic description,established with the two-scale asymptotic homogenization method,evidences the combined effect of inner resonances on the acoustic properties of the respective effective visco-thermal fluid.One type of resonance originates from strong pore-scale fluid-structure interaction,while the other one arises from pressure diffusion.These phenomena respectively cause weakly and highly damped resonances,which are activated by internal momentum or mass sources,and can largely influence,depending on the material's morphology,either the effective fluid's dynamic density,compressibility,or both.We introduce semi-analytical models to illustrate the key effective properties of the studied multiscale metamaterials.The results provide insights for the bottom-up design of multiscale acoustic metamaterials with exotic behaviors,such as the negative,very slow,or supersonic phase velocity,as well as sub-wavelength bandgaps.展开更多
Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during hom...Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during homogenization and the hot deformation behavior of the homogenized ingot were investigated in this study.The results indicate that:(1)the solidified ingot exhibits a typical dendritic microstructure,and significant element segregation occurs,leading to the presence of Ti,Nb,and Mo-rich precipitates in the interdendritic region;(2)Following homogenization,the degree of element segregation in the ingot is significantly reduced.The diffusion coefficients(D)of Ti,Nb,and Mo under various homogenization conditions were calculated.Subsequently,the diffusion constants(D_(0))and activation energies(Q)of Ti,Nb,and Mo were obtained to be 0.01432,0.00397 and 0.00195 cm^(2)/s and 244.851,230.312,and 222.125 kJ/mol,respectively.Finally,the diffusion kinetics formulas for Ti,Nb,and Mo in Alloy 625 Plus were established.After homogenization at 1220℃for 8 h,the alloy exhibits low deformation resistance,a high degree of recrystallization,and optimal deformation coordination ability.Therefore,this represents a rational single-stage homogenization process.展开更多
Surface energy is essential to the understanding of micro-mechanics for heterogeneous composites.To investigate the effective elasticity and fracture behaviors,we derive an effective surface energy based on Eshelby’s...Surface energy is essential to the understanding of micro-mechanics for heterogeneous composites.To investigate the effective elasticity and fracture behaviors,we derive an effective surface energy based on Eshelby’s equivalent inclusion theory.Within a unified theoretical framework,the effective surface energy predicts the fundamentals from elasticity to fracture,and reproduces classical homogenization methods and phase field models.The influences of elastic heterogeneity and size effects are analyzed in depth.Using the surface energy formulation,a computational model is developed by minimizing the deviation of effective elastic modulus from experimental observation.To validate our theoretical prediction,numerical simulations under tension and shear loadings for monodisperse and bidisperse particulate systems are performed,which agree well with experimental evidences.Local debondings nucleate and initiate at the inclusion-matrix interfaces,then develop into multiple interacting cracks and shear bands,thereby greatly promotes the process of fracture.展开更多
The utilization of self-assembled monolayers(SAMs)has significantly elevated the power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs).However,the inherent hydrophobicity of these SAMs poses challen...The utilization of self-assembled monolayers(SAMs)has significantly elevated the power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs).However,the inherent hydrophobicity of these SAMs poses challenges in the subsequent printing of perovskite films in PSC upscaling.In this work,we incorporated a multifunctional additive,dimethyl suberimidate dihydrochloride(DMSCl_(2)),into the perovskite precursor to enhance the quality of the blade-coated perovskite film on the SAM interlayer.Characterizations revealed that the function groups of the imino(N-H)and methoxy(CH_(3)O-)DMSCl_(2) facilitate both bonding between perovskite precursor and SAM molecule(Me-4PACz),which facilitates the large-area printing of perovskite film.These interactions also provide effective passivation within the perovskite films and interface defects of PSCs.As a result,a significantly enhanced PCE from 16.62% to 20.37% was obtained for the printed perovskite solar module(93.10 cm^(2))and 25.27% for the small device(0.09 cm^(2)).Remarkable stability was achieved with 93.3% of their initial PCE after 1000 h of continuous maximum power point(MPP)tracking.This report suggests that multifunctional additive doping provides a convenient route for the upscaling of perovskite solar cells with SAM interlayers.展开更多
The multiscale computational method with asymptotic analysis and reduced-order homogenization(ROH)gives a practical numerical solution for engineering problems,especially composite materials.Under the ROH framework,a ...The multiscale computational method with asymptotic analysis and reduced-order homogenization(ROH)gives a practical numerical solution for engineering problems,especially composite materials.Under the ROH framework,a partition-based unitcell structure at the mesoscale is utilized to give a mechanical state at the macro-scale quadrature point with pre-evaluated influence functions.In the past,the“1-phase,1-partition”rule was usually adopted in numerical analysis,where one constituent phase at the mesoscale formed one partition.The numerical cost then is significantly reduced by introducing an assumption that the mechanical responses are the same all the time at the same constituent,while it also introduces numerical inaccuracy.This study proposes a new partitioning method for fibrous unitcells under a reduced-order homogenization methodology.In this method,the fiber phase remains 1 partition,but the matrix phase is divided into 2 partitions,which refers to the“12”partitioning scheme.Analytical elastic influence+functions are derived by introducing the elastic strain energy equivalence(Hill-Mandel condition).This research also obtains the analytical eigenstrain influence functions by alleviating the so-called“inclusion-locking”phenomenon.In addition,a numerical approach to minimize the error of strain energy density is introduced to determine the partitioning of the matrix phase.Several numerical examples are presented to compare the differences among direct numerical simulation(DNS),“11”,and“12”partitioning schemes.The numerical simulations show improved++numerical accuracy by the“12”partitioning scheme.展开更多
文摘It is known that “Fish Oil” is the raw material that has lot of benefits for health, because fish oil consists of several necessary unsaturated fatty acids, particularly Omega-3 and Docosahexanoic acid (DHA). Omega-3 can decrease triglyceride level, and then it can increase HDL cholesterol level. In addition, DHA can support brain cell synthesis and also nervous system for human.
基金supported by the Distinguish Young Scholars of the National Natural Science Foundation of China (No.52225601)the Major Program of the National Natural Science Foundation of China (No.52090061)。
文摘In conventional parabolic trough collectors(PTCs),sunlight is concentrated at the bottom of the absorber tube,resulting in a significant circumferential temperature gradient across the absorber tube,heat loss and thermal deformation,which affects the safety and thermal performance of PTCs.In this study,a new receiver with homogenizer and spiral(RHS) is proposed,achieving the optical and thermal synergy to ameliorate the thermal deformation of the absorber tube and enhance thermal efficiency.A plane structure homogenizer is designed to improve uniformity of the concentrated solar flux of absorber tube through second reflection.In combination with the spiral,it improves the optical-thermal efficiency of the PTC by enhancing heat exchange between the fluid and the backlight side of the absorber tube.The performance of the collector is numerically studied by building a three-dimensional coupled light-thermal-structure model.The results show that the thermal deformation of the RHS is reduced by more than 96% and the optical-thermal efficiency is improved by 1.2%-0.63% compared with conventional receivers(CRs) under the same inlet temperature conditions.The proposed receiver is validated to be effective in reducing thermal deformation and improving optical-thermal efficiency.
文摘A Laser Doppler Anemometer (LDA) is used to measure and study the flow field in the working chamber of a homogenizer. Flow Patterns, distributions of mean and fluctuating velocities, shear rates are obtained in details. The characteristics of the flow field and the basic principles of homogenizing are presented. These results are very helpful for the improvement of fluid homogenizers.
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The National Natural Science Foundation (30671640)Agricultural Science and Technology Research Project of Jiangsu Province (BE2007326).
文摘This paper was to investigate basic properties of micro/ nano fibrils from poplar with a high pressure homogenizer. Their basic properties were tested by laser particle size analyzer, scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The test results showed that if the fiber slurry moved from 20 to 40 circulations through the homogenizer, for 10% of the micro/nano fibrils, the particle size was reduced from 1.2 μm to 160 nm and its surface area per unit volume was increased from 1.63 × 104 to 8.38 × 104 cm2/cm3 when the concentration of fiber in suspension was 0.5% and the homogenization pressure was 800 bar. A distribution in the dimensions of the cellulose whiskers was seen by scanning electron microscopy. It was proved by X-ray diffractometer that the crystal degree of the micro/nano fibrils had a small change during the conversion process.
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.
基金financially supported by the National Key R&D Program of China(No.2022YFE0121300)the National Natural Science Foundation of China(No.52374376)the Introduction Plan for High-end Foreign Experts(No.G2023105001L)。
文摘As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.
基金supported by the National Natural Science Foundation of China(No.92372123)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515012057,2022B1515020005,2023B1515130004)Guangzhou Basic and Applied Basic Research Foundation(No.202201011342).
文摘Porous organic cages(POCs)with permanent porosity and excellent host–vip property hold great potentials in regulating ion transport behavior,yet their feasibility as solid-state electrolytes has never been testified in a practical battery.Herein,we design and fabricate a quasi-solid-state electrolyte(QSSE)based on a POC to enable the stable operation of Li-metal batteries(LMBs).Benefiting from the ordered channels and cavity-induced anion-trapping effect of POC,the resulting POC-based QSSE exhibits a high Li+transference number of 0.67 and a high ionic conductivity of 1.25×10^(−4) S cm^(−1) with a low activation energy of 0.17 eV.These allow for homogeneous Li deposition and highly reversible Li plating/stripping for over 2000 h.As a proof of concept,the LMB assembled with POC-based QSSE demonstrates extremely stable cycling performance with 85%capacity retention after 1000 cycles.Therefore,our work demonstrates the practical applicability of POC as SSEs for LMBs and could be extended to other energy-storage systems,such as Na and K batteries.
基金supported by the National Nature Science Foundation of China(71771201,72531009,71973001)the USTC Research Funds of the Double First-Class Initiative(FSSF-A-240202).
文摘Social interaction with peer pressure is widely studied in social network analysis.Game theory can be utilized to model dynamic social interaction,and one class of game network models assumes that people’s decision payoff functions hinge on individual covariates and the choices of their friends.However,peer pressure would be misidentified and induce a non-negligible bias when incomplete covariates are involved in the game model.For this reason,we develop a generalized constant peer effects model based on homogeneity structure in dynamic social networks.The new model can effectively avoid bias through homogeneity pursuit and can be applied to a wider range of scenarios.To estimate peer pressure in the model,we first present two algorithms based on the initialize expand merge method and the polynomial-time twostage method to estimate homogeneity parameters.Then we apply the nested pseudo-likelihood method and obtain consistent estimators of peer pressure.Simulation evaluations show that our proposed methodology can achieve desirable and effective results in terms of the community misclassification rate and parameter estimation error.We also illustrate the advantages of our model in the empirical analysis when compared with a benchmark model.
基金National Key R&D Program Project(2022YFB3705103)。
文摘Hot compression tests for GH4706 alloy were performed at a true strain of 1.2 within the temperature range of 950-1150℃ and the strain rate range of 0.001-1 s^(-1).The optimal hot deformation temperature and strain rate range were determined using nephogram maps of dynamic recrystallization fraction,average grain size,and grain distribution standard deviation.Processing maps at true strains from 0.4 to 0.9 were generated based on flow stress curves to identify the strain corresponding to optimal microstructure homogenization efficiency at various temperatures and strain rates.Results show that within the optimal parameter range,under the conditions of 1150℃ and 0.01 s^(-1),the true strain of about 0.6 results in the optimal microstructure homogenization efficiency.The grain orientation spread maps obtained from the experiment also confirms this conclusion.This study provides an effective method for microstructure homogenization control of GH4706 alloy and an effective reference for the minimum strain threshold of the local part of the forging in engineering.
文摘To achieve efficient catalytic hydrogenation of CO_(2)to formate,we employed a transmetallation strategy to develop three novel iridium(Ⅰ)complexes,which feature N‑heterocyclic carbene‑nitrogen‑phosphine ligands(CNP)and a 1,5‑cyclooctadiene(cod)molecule:[Ir(cod)(κ^(3)‑CN^(im)P)]Cl(1⁃Cl),[Ir(cod)(κ^(3)‑CN^(im)P)]PF6(1⁃PF_(6)),and[Ir(cod)(κ^(3)‑CNHP)]Cl(2).The^(1)H NMR spectra,^(31)P NMR spectra,and high‑resolution mass spectra verify the successful synthesis of these three Ir(Ⅰ)‑CNP complexes.Furthermore,single‑crystal X‑ray diffraction analysis confirms the coordination geometry of 1⁃PF_(6).The strong Ir—C(NHC)bond suggests that the carbene carbon plays an enhanced anchoring role to iridium due to its strongσ‑donating ability,which helps stabilize the active metal species during CO_(2)hydrogenation.As a result,the Ir(Ⅰ)‑CNP complex exhibits remarkable activity and long catalytic lifetime for the hydrogenation of CO_(2)to formate,reaching a turnover number(TON)of 1.16×10^(6)after 150 h at a high temperature of 170℃,which was a relatively high value among all the Ir complexes.CCDC:2384071,1⁃PF_(6).
基金the National Natural Science Foundation of China(No.22271060),The Department of Chemistry at Fudan University and College of Chemistry and Chemical Engineering at Ningxia University is gratefully acknowledged.
文摘Photoredox catalysis has made significant advances in stateof-the-art chemical synthesis,drawing energy from inexhaustible light and enabling various organic transformations to occur under mild reaction conditions.Over the past few years,a variety of homogeneous and heterogeneous photocatalysts have been applied in the photoredox catalysis.Heterogeneous photoredox catalysis offers advantages such as easy separation and superior recyclability compared to homogeneous counterparts,although homogenous catalysts are usually associated with higher activities and selectivity.From a practical perspective,an optimal photoredox catalytic system would integrate the advantages of both homogeneous and heterogeneous cases.
基金supported by the National Natural Science Foundation of China(Grant Nos.U21A20130 and 52475357).
文摘1.Introduction Al-Zn-Mg-Cu alloy is a typical age-hardening aluminum alloy,its strength and toughness are significantly influenced by precipita-tion behavior.The nucleation mechanisms of precipitates in this alloy are generally categorized into homogeneous and heterogeneous nucleation.Homogeneous nucleation relies on structural and energy fluctuations within the solution to generate the driving force necessary for direct nucleation.
基金Project supported by the Chilean National Agency for Research and Development(ANID)through Grants ANID FONDECYT Regular(Nos.1211310 and 1250496)ANID Anillo de Tecnologia(No.ACT240015)the Polish National Science Centre(NCN)through Grant Agreement(No.2021/41/B/ST8/04492)。
文摘The acoustic wave propagation in gas-saturated double-porosity materials composed of a microporous matrix and mesopores with arrays of plate-type resonators is investigated.A macroscopic description,established with the two-scale asymptotic homogenization method,evidences the combined effect of inner resonances on the acoustic properties of the respective effective visco-thermal fluid.One type of resonance originates from strong pore-scale fluid-structure interaction,while the other one arises from pressure diffusion.These phenomena respectively cause weakly and highly damped resonances,which are activated by internal momentum or mass sources,and can largely influence,depending on the material's morphology,either the effective fluid's dynamic density,compressibility,or both.We introduce semi-analytical models to illustrate the key effective properties of the studied multiscale metamaterials.The results provide insights for the bottom-up design of multiscale acoustic metamaterials with exotic behaviors,such as the negative,very slow,or supersonic phase velocity,as well as sub-wavelength bandgaps.
基金Project(52174303)supported by the National Natural Science Foundation of ChinaProject(2023JH2/101700302)supported by the Joint Program of Science and Technology Plans in Liaoning Province,China。
文摘Based on microstructure analysis,diffusion theory,and hot deformation experiments,the solidification microstructure and element segregation of the Alloy 625 Plus ingot,the diffusion kinetics of Ti,Nb,and Mo during homogenization and the hot deformation behavior of the homogenized ingot were investigated in this study.The results indicate that:(1)the solidified ingot exhibits a typical dendritic microstructure,and significant element segregation occurs,leading to the presence of Ti,Nb,and Mo-rich precipitates in the interdendritic region;(2)Following homogenization,the degree of element segregation in the ingot is significantly reduced.The diffusion coefficients(D)of Ti,Nb,and Mo under various homogenization conditions were calculated.Subsequently,the diffusion constants(D_(0))and activation energies(Q)of Ti,Nb,and Mo were obtained to be 0.01432,0.00397 and 0.00195 cm^(2)/s and 244.851,230.312,and 222.125 kJ/mol,respectively.Finally,the diffusion kinetics formulas for Ti,Nb,and Mo in Alloy 625 Plus were established.After homogenization at 1220℃for 8 h,the alloy exhibits low deformation resistance,a high degree of recrystallization,and optimal deformation coordination ability.Therefore,this represents a rational single-stage homogenization process.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172062 and 12588201).
文摘Surface energy is essential to the understanding of micro-mechanics for heterogeneous composites.To investigate the effective elasticity and fracture behaviors,we derive an effective surface energy based on Eshelby’s equivalent inclusion theory.Within a unified theoretical framework,the effective surface energy predicts the fundamentals from elasticity to fracture,and reproduces classical homogenization methods and phase field models.The influences of elastic heterogeneity and size effects are analyzed in depth.Using the surface energy formulation,a computational model is developed by minimizing the deviation of effective elastic modulus from experimental observation.To validate our theoretical prediction,numerical simulations under tension and shear loadings for monodisperse and bidisperse particulate systems are performed,which agree well with experimental evidences.Local debondings nucleate and initiate at the inclusion-matrix interfaces,then develop into multiple interacting cracks and shear bands,thereby greatly promotes the process of fracture.
基金financially supported by the Guangdong Pearl River Talent Program(2021ZT09L400)the National Natural Science Foundation of China(52302195,52072284)+1 种基金the Joint Funds of Natural Science Foundation of Hubei Province(2022CFD087)the Scientific Research and Technology Development Project of China National Petroleum Corporation(Grant Nos.2024ZG50)。
文摘The utilization of self-assembled monolayers(SAMs)has significantly elevated the power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs).However,the inherent hydrophobicity of these SAMs poses challenges in the subsequent printing of perovskite films in PSC upscaling.In this work,we incorporated a multifunctional additive,dimethyl suberimidate dihydrochloride(DMSCl_(2)),into the perovskite precursor to enhance the quality of the blade-coated perovskite film on the SAM interlayer.Characterizations revealed that the function groups of the imino(N-H)and methoxy(CH_(3)O-)DMSCl_(2) facilitate both bonding between perovskite precursor and SAM molecule(Me-4PACz),which facilitates the large-area printing of perovskite film.These interactions also provide effective passivation within the perovskite films and interface defects of PSCs.As a result,a significantly enhanced PCE from 16.62% to 20.37% was obtained for the printed perovskite solar module(93.10 cm^(2))and 25.27% for the small device(0.09 cm^(2)).Remarkable stability was achieved with 93.3% of their initial PCE after 1000 h of continuous maximum power point(MPP)tracking.This report suggests that multifunctional additive doping provides a convenient route for the upscaling of perovskite solar cells with SAM interlayers.
基金funded by the National Key R&D Program of China(Grant No.2023YFA1008901)the National Natural Science Foundation of China(Grant Nos.11988102,12172009)“The Fundamental Research Funds for the Central Universities,Peking University”.
文摘The multiscale computational method with asymptotic analysis and reduced-order homogenization(ROH)gives a practical numerical solution for engineering problems,especially composite materials.Under the ROH framework,a partition-based unitcell structure at the mesoscale is utilized to give a mechanical state at the macro-scale quadrature point with pre-evaluated influence functions.In the past,the“1-phase,1-partition”rule was usually adopted in numerical analysis,where one constituent phase at the mesoscale formed one partition.The numerical cost then is significantly reduced by introducing an assumption that the mechanical responses are the same all the time at the same constituent,while it also introduces numerical inaccuracy.This study proposes a new partitioning method for fibrous unitcells under a reduced-order homogenization methodology.In this method,the fiber phase remains 1 partition,but the matrix phase is divided into 2 partitions,which refers to the“12”partitioning scheme.Analytical elastic influence+functions are derived by introducing the elastic strain energy equivalence(Hill-Mandel condition).This research also obtains the analytical eigenstrain influence functions by alleviating the so-called“inclusion-locking”phenomenon.In addition,a numerical approach to minimize the error of strain energy density is introduced to determine the partitioning of the matrix phase.Several numerical examples are presented to compare the differences among direct numerical simulation(DNS),“11”,and“12”partitioning schemes.The numerical simulations show improved++numerical accuracy by the“12”partitioning scheme.
