A series of granular activated carbons （GACs） were prepared by briquetting method from Chinese coals of different ranks and their blends, with coal pitch as the binder. Pore structural parameters including BET speci...A series of granular activated carbons （GACs） were prepared by briquetting method from Chinese coals of different ranks and their blends, with coal pitch as the binder. Pore structural parameters including BET specific surface area （SBEr）, total pore volume （Vr） and average pore diameter （da） were measured and cal- culated as well as process parameters such as yield of char （CY） and burn-off （B）. The relationship between the pore structural parameters of the GAC from coal blend （BC-GAC） and the ones of the GACs from corresponding single coals （SC-GACs） was analyzed, in which an index, the relative error （δ）, was presented to define the bias between fitted values and experimental values of these parameters of the BC-GACs. The results show that the BC-GAC keeps qualitatively the pore structural features of the SC-GACs; as concerned as the quantitative relationship, the pore structural parameters of the BC-GAC from coal blend consisting of non-caking coals can be obtained by adding proportionally the pore structural parameters of the SC-GACs with a less than 10%. Meanwhile, for the BC-GAC from coal blend containing weak caking bituminous coal, the δ increases up to 25% and the experimental pore size distribution differs greatly from the fitted one.展开更多
Taking into consideration the changes of the geometric shielding effect in a molecule as the energy of incident electrons varies, this paper presents an empirical fraction, which depends on the energy of incident elec...Taking into consideration the changes of the geometric shielding effect in a molecule as the energy of incident electrons varies, this paper presents an empirical fraction, which depends on the energy of incident electrons, the target＇s molecular dimension and the atomic and electronic numbers in the molecule. Using this empirical fraction, it proposes a new formulation of the additivity rule. Employing the new additivity rule, it calculates the total cross sections of electron scattering by C2H4, C6H6, C6H14 and C8H18 over the energy range from 50 to 5000eV. In order to exclude the calculation deviations caused by solving the radial Schrodinger equation of electron scattering by atoms, here the atomic cross sections are derived from the experimental total cross section results of simple molecules （H2, O2, CO） via the inversion algorithm. The quantitative total cross sections are compared with those obtained by experiments and other theories, and good agreement is obtained over a wide energy range, even at energy of several tens of eV.展开更多
Phase space can be constructed for N equal and distinguishable binary subsystems which are correlated in a scale-invariant manner. In the paper, correlation coefficient and reduced probability are introduced to charac...Phase space can be constructed for N equal and distinguishable binary subsystems which are correlated in a scale-invariant manner. In the paper, correlation coefficient and reduced probability are introduced to characterize the scale-invariant correlated binary subsystems. Probabilistic sets for the correlated binary subsystems satisfy Leibnitz triangle rule in the sense that the marginal probabilities of N-system are equal to the joint probabilities of the （N - 1）-system. For entropic index q ≠ 1, nonextensive entropy Sq is shown to be additive in the scale-invariant occupation of phase space.展开更多
Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of o...Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil supplemented.An experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing pigs.Methods Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal ileum.The experimental diets included a fat-free basal diet and 5 oil-added diets.The 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal diet.The 5 oils were palm oil(U:S=1.2),canola oil(U:S=12.0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,respectively.Results The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(P<0.05)as the U:S of dietary oils increased except for SID of fat and C18:2.The AID and SID of fat and fatty acids differed among the dietary treatments(P<0.05)except for SID of unsaturated fatty acids(UFA)and C18:2.Fitted one-slope broken-line analyses for the SID of fat,saturated fatty acids(SFA)and UFA indicated that the breakpoint for U:S of oil was 4.14(R^(2)=0.89,P<0.01),2.91(R^(2)=0.98,P<0.01)and 3.84(R^(2)=0.85,P<0.01),respectively.The determined SID of fat,C18:1,C18:2 and UFA in the mixtures was not different from the calculated SID of fat,C18:1,C18:2 and UFA.However,the determined SID of C16:0,C18:0 and SFA in the mixtures were greater than the calculated SID values(P<0.05).The abundance of Romboutsia and Turicibacter in pigs fed diet containing palm oil was greater than that in rapeseed oil treatment group,and the two bacteria were negatively correlated with SID of C16:0,C18:0 and SFA(P<0.05).Conclusions The optimal U:S for improving the utilization efficiency of mixed oil was 4.14.The SID of fat and UFA for palm oil and canola oil were additive in growing pigs,whereas the SID of SFA in the mixture of two oils was greater than the sum of the values of pure oils.Differences in fat digestibility caused by oils differing in degree of saturation has a significant impact on bacterial community in the foregut.展开更多
The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluorometha...The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluoromethanes （CF4, CF3H, CF2H2, and CFH3） are calculated in an energy range from 100 eV to 1500 eV by the revised additivity rule. The present calculations are compared with the original additivity rule results and the available experimental data. Better agreement with each other is obtained.展开更多
In this paper,we study the stability of the orthogonal equation,which is closely related to the results by W.Fechner and J.Sikorska in 2010.There are some differences that we consider the target space with theβ-homog...In this paper,we study the stability of the orthogonal equation,which is closely related to the results by W.Fechner and J.Sikorska in 2010.There are some differences that we consider the target space with theβ-homogeneous norm and quasi-norm.Overcoming theβ-homogeneous norm and quasi-norm bottlenecks,we get some new results.展开更多
This study was to compare the estimates of basal endogenous losses(BEL)of amino acids(AA)determined by 3 methods including feeding a nitrogen-free diet(NFD)or a low-casein diet(LCD,containing casein at 30 g/kg diet)or...This study was to compare the estimates of basal endogenous losses(BEL)of amino acids(AA)determined by 3 methods including feeding a nitrogen-free diet(NFD)or a low-casein diet(LCD,containing casein at 30 g/kg diet)or using the regression method.Another objective was to investigate whether the ileal AA digestibility of corn calculated from a casein-supplemented corn diet is additive for a cornsoybean meal(SBM)mixed diet in broilers.On d 31 of age,168 Ross 308 male broilers were assigned to 8 dietary treatments with 6 replicates in a randomized complete block design.An NFD and 3 diets containing 30,60,or 90 g/kg of casein were formulated to determine the BEL of AA and ileal AA digestibility of casein.The other 4 diets consisted of a corn diet,SBM diet,casein-supplemented corn diet,and corn-SBM mixed diet.On d 35 of age,digesta from the distal section of the ileum were collected.The BEL of AA in birds fed the LCD were greater(P<0.05)than those of the NFD and the regression method.There were no differences in the BEL of AA determined between the NFD and the regression method.Apparent ileal digestibility(AID)and standardized ileal digestibility(SID)of AA for corn calculated from the casein-supplemented corn diet were greater(P<0.05)than those of the corn diet.The predicted AID of Thr in the corn-SBM mixed diet based on the AID of AA for corn in the corn diet was lower(P<0.05)than the measured AID.However,the predicted AID of AA in the mixed diet based on the AID of AA for corn in the casein-supplemented corn diet did not differ from the measured AID.The predicted SID of AA in the mixed diet did not differ from the measured SID irrespective of casein supplementation.In conclusion,feeding an NFD or using the regression method yields similar BEL of AA,but not feeding an LCD.Casein supplementation in the corn diet increases the ileal AA digestibility for corn,which is additive for the corn-SBM mixed diet.展开更多
Regression splines are often used for fitting nonparametric functions, and they work especially well for additivity models. In this paper, we consider two simple tests of additivity: an adaptation of Tukey’s one degr...Regression splines are often used for fitting nonparametric functions, and they work especially well for additivity models. In this paper, we consider two simple tests of additivity: an adaptation of Tukey’s one degree of freedom test and a nonparametric version of Rao’s score test. While the Tukey-type test can detect most forms of the local non-additivity at the parametric rate of O(n-1/2), the score test is consistent for all alternative at a nonparametric rate. The asymptotic distribution of these test statistics is derived under both the null and local alternative hypotheses. A simulation study is conducted to compare their finite-sample performances with some existing kernel-based tests. The score test is found to have a good overall performance.展开更多
Observed effects of metal mixtures on animals and plants often differ from the estimates, which are commonly calculated by adding up the biological responses of individual metals. This difference from additivity is co...Observed effects of metal mixtures on animals and plants often differ from the estimates, which are commonly calculated by adding up the biological responses of individual metals. This difference from additivity is commonly referred to as being a consequence of specific interactions between metals. The science of how to quantify metal interactions and whether to include them in risk assessment models is in its infancy. This review summarizes the existing predictive tools for evaluating the combined toxicity of metals present in mixtures and indicates the advantages and disadvantages of each method. We intend to provide eco-toxicologists with background information on how to make good use of the tools and how to advance the methods for assessing toxicity of metal mixtures, It is concluded that statistically significant deviations from additivity are not necessarily biologically relevant. Incorporation of interactions between metals in a model does not on forehand mean that the model is more accurate than a model developed based on additivity only. It is recommended to first use a relatively simple method for effect prediction of uninvestigated metal mixtures. To improve the reliability of toxicity modeling for metal mixtures, further efforts should focus on balancing the relationship between the significance of statistics and the biological meaning, and unraveling the toxicity mechanisms of metals and their mixtures.展开更多
Additive manufacturing(AM),with its high flexibility,cost-effectiveness,and customization,significantly accelerates the advancement of nanogenerators,contributing to sustainable energy solutions and the Internet of Th...Additive manufacturing(AM),with its high flexibility,cost-effectiveness,and customization,significantly accelerates the advancement of nanogenerators,contributing to sustainable energy solutions and the Internet of Things.In this review,an in-depth analysis of AM for piezoelectric and triboelectric nanogenerators is presented from the perspectives of fundamental mechanisms,recent advancements,and future prospects.It highlights AM-enabled advantages of versatility across materials,structural topology optimization,microstructure design,and integrated printing,which enhance critical performance indicators of nanogenerators,such as surface charge density and piezoelectric constant,thereby improving device performance compared to conventional fabrication.Common AM techniques for nanogenerators,including fused deposition modeling,direct ink writing,stereolithography,and digital light processing,are systematically examined in terms of their working principles,improved metrics(output voltage/current,power density),theoretical explanation,and application scopes.Hierarchical relationships connecting AM technologies with performance optimization and applications of nanogenerators are elucidated,providing a solid foundation for advancements in energy harvesting,self-powered sensors,wearable devices,and human-machine interaction.Furthermore,the challenges related to fabrication quality,cross-scale manufacturing,processing efficiency,and industrial deployment are critically discussed.Finally,the future prospects of AM for nanogenerators are explored,aiming to foster continuous progress and innovation in this field.展开更多
Aqueous zinc metal batteries(AZMBs)are promising candidates for renewable energy storage,yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth.Alth...Aqueous zinc metal batteries(AZMBs)are promising candidates for renewable energy storage,yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth.Although organic additives can enhance the antifreeze properties of electrolytes,their weak polarity diminishes ionic conductivity,and their flammability poses safety concerns,undermining the inherent advantages of aqueous systems.Herein,we present a cost-effective and highly stable Na_(2)SO_(4)additive introduced into a Zn(ClO_(4))2-based electrolyte to create an organic-free antifreeze electrolyte.Through Raman spectroscopy,in situ optical microscopy,densityfunctional theory computations,and molecular dynamics simulations,we demonstrate that Na+ions improve low-temperature electrolyte performance and mitigate dendrite formation by regulating uniform Zn^(2+)deposition through preferential adsorption and electrostatic interactions.As a result,the Zn||Zn cells using this electrolyte achieve a remarkable cycling life of 360 h at-40℃ with 61% depth of discharge,and the Zn||PANI cells retained an ultrahigh capacity retention of 91%even after 8000 charge/discharge cycles at-40℃.This work proposes a cost-effective and practical approach for enhancing the long-term operational stability of AZMBs in low-temperature environments.展开更多
本文聚焦我国青海湖流域的水文过程,基于多年气象和水文动态数据,发展了一种融合概念性水文模型FLEX (FluxExchange)和门控循环单元(Gated Recurrent Unit, GRU)的混合模型对流域内最大支流布哈河的逐日径流进行了模拟和预测。在构建混...本文聚焦我国青海湖流域的水文过程,基于多年气象和水文动态数据,发展了一种融合概念性水文模型FLEX (FluxExchange)和门控循环单元(Gated Recurrent Unit, GRU)的混合模型对流域内最大支流布哈河的逐日径流进行了模拟和预测。在构建混合模型中,采用了三种策略提升模拟精度:引入差分进化自适应算法DREAM(zs)反演水文参数优化FLEX模型;采用变分模态分解(VMD)提取径流数据的信息和特征;利用麻雀搜索算法(SSA)优化深度学习GRU的参数。研究将FLEX模型的模拟结果连同气象数据一起作为神经网络的输入,从而构建了FLEX-VMD-SSA-GRU混合模型。同时,探讨了不同的气象输入条件对模拟结果的影响和贡献:基于7个主要气象要素,由少及多设置了14组输入情景模拟。最后通过SHAP对深度学习方法的结果进行分析,揭示了气象变量对径流长期趋势的贡献和重要度。展开更多
Sinter is the core raw material for blast furnaces.Flue pressure,which is an important state parameter,affects sinter quality.In this paper,flue pressure prediction and optimization were studied based on the shapley a...Sinter is the core raw material for blast furnaces.Flue pressure,which is an important state parameter,affects sinter quality.In this paper,flue pressure prediction and optimization were studied based on the shapley additive explanation(SHAP)to predict the flue pressure and take targeted adjustment measures.First,the sintering process data were collected and processed.A flue pressure prediction model was then constructed after comparing different feature selection methods and model algorithms using SHAP+extremely random-ized trees(ET).The prediction accuracy of the model within the error range of±0.25 kPa was 92.63%.SHAP analysis was employed to improve the interpretability of the prediction model.The effects of various sintering operation parameters on flue pressure,the relation-ship between the numerical range of key operation parameters and flue pressure,the effect of operation parameter combinations on flue pressure,and the prediction process of the flue pressure prediction model on a single sample were analyzed.A flue pressure optimization module was also constructed and analyzed when the prediction satisfied the judgment conditions.The operating parameter combination was then pushed.The flue pressure was increased by 5.87%during the verification process,achieving a good optimization effect.展开更多
At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass components.In this study,multi-laye...At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass components.In this study,multi-layer multi-pass FRAM-deposited alumin-um alloy samples were successfully prepared using a non-shoulder tool head.The material flow behavior and microstructure of the over-lapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition were studied using the hybrid 6061 and 5052 aluminum alloys.The results showed that a mechanical interlocking structure was formed between the adjacent layers and the adja-cent passes in the overlapped center area.Repeated friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone,which made the recrystallization degree in the left and right edge zones of the over-lapped zone the highest,followed by the overlapped center zone and the non-overlapped zone.The tensile strength of the overlapped zone exceeded 90%of that of the single-pass deposition sample.It is proved that although there are uneven grooves on the surface of the over-lapping area during multi-layer and multi-pass deposition,they can be filled by the flow of materials during the deposition of the next lay-er,thus ensuring the dense microstructure and excellent mechanical properties of the overlapping area.The multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.展开更多
基金financially supported by the National High-Tech Research and Development Program of China (No.2008AA05Z308)the National Natural Science Foundation of China (No.20776150)
文摘A series of granular activated carbons （GACs） were prepared by briquetting method from Chinese coals of different ranks and their blends, with coal pitch as the binder. Pore structural parameters including BET specific surface area （SBEr）, total pore volume （Vr） and average pore diameter （da） were measured and cal- culated as well as process parameters such as yield of char （CY） and burn-off （B）. The relationship between the pore structural parameters of the GAC from coal blend （BC-GAC） and the ones of the GACs from corresponding single coals （SC-GACs） was analyzed, in which an index, the relative error （δ）, was presented to define the bias between fitted values and experimental values of these parameters of the BC-GACs. The results show that the BC-GAC keeps qualitatively the pore structural features of the SC-GACs; as concerned as the quantitative relationship, the pore structural parameters of the BC-GAC from coal blend consisting of non-caking coals can be obtained by adding proportionally the pore structural parameters of the SC-GACs with a less than 10%. Meanwhile, for the BC-GAC from coal blend containing weak caking bituminous coal, the δ increases up to 25% and the experimental pore size distribution differs greatly from the fitted one.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574039)the Program for Science and Technology Innovation Talents in Universities of Henan Province in China (Grant No 2008HASTIT008)
文摘Taking into consideration the changes of the geometric shielding effect in a molecule as the energy of incident electrons varies, this paper presents an empirical fraction, which depends on the energy of incident electrons, the target＇s molecular dimension and the atomic and electronic numbers in the molecule. Using this empirical fraction, it proposes a new formulation of the additivity rule. Employing the new additivity rule, it calculates the total cross sections of electron scattering by C2H4, C6H6, C6H14 and C8H18 over the energy range from 50 to 5000eV. In order to exclude the calculation deviations caused by solving the radial Schrodinger equation of electron scattering by atoms, here the atomic cross sections are derived from the experimental total cross section results of simple molecules （H2, O2, CO） via the inversion algorithm. The quantitative total cross sections are compared with those obtained by experiments and other theories, and good agreement is obtained over a wide energy range, even at energy of several tens of eV.
基金the National Natural Science Foundation of China(No.60474069)
文摘Phase space can be constructed for N equal and distinguishable binary subsystems which are correlated in a scale-invariant manner. In the paper, correlation coefficient and reduced probability are introduced to characterize the scale-invariant correlated binary subsystems. Probabilistic sets for the correlated binary subsystems satisfy Leibnitz triangle rule in the sense that the marginal probabilities of N-system are equal to the joint probabilities of the （N - 1）-system. For entropic index q ≠ 1, nonextensive entropy Sq is shown to be additive in the scale-invariant occupation of phase space.
基金supported by National Natural Science Foundation of China(31972597 and 32302793)。
文摘Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil supplemented.An experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing pigs.Methods Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal ileum.The experimental diets included a fat-free basal diet and 5 oil-added diets.The 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal diet.The 5 oils were palm oil(U:S=1.2),canola oil(U:S=12.0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,respectively.Results The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(P<0.05)as the U:S of dietary oils increased except for SID of fat and C18:2.The AID and SID of fat and fatty acids differed among the dietary treatments(P<0.05)except for SID of unsaturated fatty acids(UFA)and C18:2.Fitted one-slope broken-line analyses for the SID of fat,saturated fatty acids(SFA)and UFA indicated that the breakpoint for U:S of oil was 4.14(R^(2)=0.89,P<0.01),2.91(R^(2)=0.98,P<0.01)and 3.84(R^(2)=0.85,P<0.01),respectively.The determined SID of fat,C18:1,C18:2 and UFA in the mixtures was not different from the calculated SID of fat,C18:1,C18:2 and UFA.However,the determined SID of C16:0,C18:0 and SFA in the mixtures were greater than the calculated SID values(P<0.05).The abundance of Romboutsia and Turicibacter in pigs fed diet containing palm oil was greater than that in rapeseed oil treatment group,and the two bacteria were negatively correlated with SID of C16:0,C18:0 and SFA(P<0.05).Conclusions The optimal U:S for improving the utilization efficiency of mixed oil was 4.14.The SID of fat and UFA for palm oil and canola oil were additive in growing pigs,whereas the SID of SFA in the mixture of two oils was greater than the sum of the values of pure oils.Differences in fat digestibility caused by oils differing in degree of saturation has a significant impact on bacterial community in the foregut.
基金Project supported by the Natural Science Foundation of Shandong Province,China (Grant No. ZR2011AL021)the National Natural Science Foundation of China (Grant No. 11074104)+1 种基金the Research Foundation of Ludong University,China (Grant No. LY20072801)the Discipline Construction Fund of Ludong University,China
文摘The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluoromethanes （CF4, CF3H, CF2H2, and CFH3） are calculated in an energy range from 100 eV to 1500 eV by the revised additivity rule. The present calculations are compared with the original additivity rule results and the available experimental data. Better agreement with each other is obtained.
基金Supported by the National Natural Science Foundation of China(Grant Nos.1197149312071491)the Fundamental Research Funds for the Central Universities(Grant No.2021qntd21)。
文摘In this paper,we study the stability of the orthogonal equation,which is closely related to the results by W.Fechner and J.Sikorska in 2010.There are some differences that we consider the target space with theβ-homogeneous norm and quasi-norm.Overcoming theβ-homogeneous norm and quasi-norm bottlenecks,we get some new results.
文摘This study was to compare the estimates of basal endogenous losses(BEL)of amino acids(AA)determined by 3 methods including feeding a nitrogen-free diet(NFD)or a low-casein diet(LCD,containing casein at 30 g/kg diet)or using the regression method.Another objective was to investigate whether the ileal AA digestibility of corn calculated from a casein-supplemented corn diet is additive for a cornsoybean meal(SBM)mixed diet in broilers.On d 31 of age,168 Ross 308 male broilers were assigned to 8 dietary treatments with 6 replicates in a randomized complete block design.An NFD and 3 diets containing 30,60,or 90 g/kg of casein were formulated to determine the BEL of AA and ileal AA digestibility of casein.The other 4 diets consisted of a corn diet,SBM diet,casein-supplemented corn diet,and corn-SBM mixed diet.On d 35 of age,digesta from the distal section of the ileum were collected.The BEL of AA in birds fed the LCD were greater(P<0.05)than those of the NFD and the regression method.There were no differences in the BEL of AA determined between the NFD and the regression method.Apparent ileal digestibility(AID)and standardized ileal digestibility(SID)of AA for corn calculated from the casein-supplemented corn diet were greater(P<0.05)than those of the corn diet.The predicted AID of Thr in the corn-SBM mixed diet based on the AID of AA for corn in the corn diet was lower(P<0.05)than the measured AID.However,the predicted AID of AA in the mixed diet based on the AID of AA for corn in the casein-supplemented corn diet did not differ from the measured AID.The predicted SID of AA in the mixed diet did not differ from the measured SID irrespective of casein supplementation.In conclusion,feeding an NFD or using the regression method yields similar BEL of AA,but not feeding an LCD.Casein supplementation in the corn diet increases the ileal AA digestibility for corn,which is additive for the corn-SBM mixed diet.
基金This work was partially supported by the National Natural Science Foundation of China (Grant No. 10231030)the Excellent Young Teacher Foundation of Education Ministry of China and University of Illinois Campus Research Board and by NSF Award SBR-9617278 and DMS-0102411
文摘Regression splines are often used for fitting nonparametric functions, and they work especially well for additivity models. In this paper, we consider two simple tests of additivity: an adaptation of Tukey’s one degree of freedom test and a nonparametric version of Rao’s score test. While the Tukey-type test can detect most forms of the local non-additivity at the parametric rate of O(n-1/2), the score test is consistent for all alternative at a nonparametric rate. The asymptotic distribution of these test statistics is derived under both the null and local alternative hypotheses. A simulation study is conducted to compare their finite-sample performances with some existing kernel-based tests. The score test is found to have a good overall performance.
文摘Observed effects of metal mixtures on animals and plants often differ from the estimates, which are commonly calculated by adding up the biological responses of individual metals. This difference from additivity is commonly referred to as being a consequence of specific interactions between metals. The science of how to quantify metal interactions and whether to include them in risk assessment models is in its infancy. This review summarizes the existing predictive tools for evaluating the combined toxicity of metals present in mixtures and indicates the advantages and disadvantages of each method. We intend to provide eco-toxicologists with background information on how to make good use of the tools and how to advance the methods for assessing toxicity of metal mixtures, It is concluded that statistically significant deviations from additivity are not necessarily biologically relevant. Incorporation of interactions between metals in a model does not on forehand mean that the model is more accurate than a model developed based on additivity only. It is recommended to first use a relatively simple method for effect prediction of uninvestigated metal mixtures. To improve the reliability of toxicity modeling for metal mixtures, further efforts should focus on balancing the relationship between the significance of statistics and the biological meaning, and unraveling the toxicity mechanisms of metals and their mixtures.
基金support from the Research Committee of The Hong Kong Polytechnic University(Project codes:RMJK and 4-ZZSJ)supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.PolyU15212523).
文摘Additive manufacturing(AM),with its high flexibility,cost-effectiveness,and customization,significantly accelerates the advancement of nanogenerators,contributing to sustainable energy solutions and the Internet of Things.In this review,an in-depth analysis of AM for piezoelectric and triboelectric nanogenerators is presented from the perspectives of fundamental mechanisms,recent advancements,and future prospects.It highlights AM-enabled advantages of versatility across materials,structural topology optimization,microstructure design,and integrated printing,which enhance critical performance indicators of nanogenerators,such as surface charge density and piezoelectric constant,thereby improving device performance compared to conventional fabrication.Common AM techniques for nanogenerators,including fused deposition modeling,direct ink writing,stereolithography,and digital light processing,are systematically examined in terms of their working principles,improved metrics(output voltage/current,power density),theoretical explanation,and application scopes.Hierarchical relationships connecting AM technologies with performance optimization and applications of nanogenerators are elucidated,providing a solid foundation for advancements in energy harvesting,self-powered sensors,wearable devices,and human-machine interaction.Furthermore,the challenges related to fabrication quality,cross-scale manufacturing,processing efficiency,and industrial deployment are critically discussed.Finally,the future prospects of AM for nanogenerators are explored,aiming to foster continuous progress and innovation in this field.
基金financially supported by the National Natural Science Foundation of China(Grant No.52377206,52307237)Natural Science Foundation of Heilongjiang Province of China(YQ2024E046)Postdoctoral Science Foundation of Heilongjiang Province of China(LBH-TZ2413,LBH-Z23198)。
文摘Aqueous zinc metal batteries(AZMBs)are promising candidates for renewable energy storage,yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth.Although organic additives can enhance the antifreeze properties of electrolytes,their weak polarity diminishes ionic conductivity,and their flammability poses safety concerns,undermining the inherent advantages of aqueous systems.Herein,we present a cost-effective and highly stable Na_(2)SO_(4)additive introduced into a Zn(ClO_(4))2-based electrolyte to create an organic-free antifreeze electrolyte.Through Raman spectroscopy,in situ optical microscopy,densityfunctional theory computations,and molecular dynamics simulations,we demonstrate that Na+ions improve low-temperature electrolyte performance and mitigate dendrite formation by regulating uniform Zn^(2+)deposition through preferential adsorption and electrostatic interactions.As a result,the Zn||Zn cells using this electrolyte achieve a remarkable cycling life of 360 h at-40℃ with 61% depth of discharge,and the Zn||PANI cells retained an ultrahigh capacity retention of 91%even after 8000 charge/discharge cycles at-40℃.This work proposes a cost-effective and practical approach for enhancing the long-term operational stability of AZMBs in low-temperature environments.
文摘本文聚焦我国青海湖流域的水文过程,基于多年气象和水文动态数据,发展了一种融合概念性水文模型FLEX (FluxExchange)和门控循环单元(Gated Recurrent Unit, GRU)的混合模型对流域内最大支流布哈河的逐日径流进行了模拟和预测。在构建混合模型中,采用了三种策略提升模拟精度:引入差分进化自适应算法DREAM(zs)反演水文参数优化FLEX模型;采用变分模态分解(VMD)提取径流数据的信息和特征;利用麻雀搜索算法(SSA)优化深度学习GRU的参数。研究将FLEX模型的模拟结果连同气象数据一起作为神经网络的输入,从而构建了FLEX-VMD-SSA-GRU混合模型。同时,探讨了不同的气象输入条件对模拟结果的影响和贡献:基于7个主要气象要素,由少及多设置了14组输入情景模拟。最后通过SHAP对深度学习方法的结果进行分析,揭示了气象变量对径流长期趋势的贡献和重要度。
基金supported by the General Program of the National Natural Science Foundation of China(No.52274326)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202109)the Seventh Batch of Ten Thousand Talents Plan of China(No.ZX20220553).
文摘Sinter is the core raw material for blast furnaces.Flue pressure,which is an important state parameter,affects sinter quality.In this paper,flue pressure prediction and optimization were studied based on the shapley additive explanation(SHAP)to predict the flue pressure and take targeted adjustment measures.First,the sintering process data were collected and processed.A flue pressure prediction model was then constructed after comparing different feature selection methods and model algorithms using SHAP+extremely random-ized trees(ET).The prediction accuracy of the model within the error range of±0.25 kPa was 92.63%.SHAP analysis was employed to improve the interpretability of the prediction model.The effects of various sintering operation parameters on flue pressure,the relation-ship between the numerical range of key operation parameters and flue pressure,the effect of operation parameter combinations on flue pressure,and the prediction process of the flue pressure prediction model on a single sample were analyzed.A flue pressure optimization module was also constructed and analyzed when the prediction satisfied the judgment conditions.The operating parameter combination was then pushed.The flue pressure was increased by 5.87%during the verification process,achieving a good optimization effect.
基金supported by the National Key Research and Development Program of China(No.2022YFB3404700)the National Natural Science Foundation of China(Nos.52105313 and 52275299)+2 种基金the Research and Development Program of Beijing Municipal Education Commission,China(No.KM202210005036)the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-MSX0701)the National Defense Basic Research Projects of China(No.JCKY2022405C002).
文摘At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass components.In this study,multi-layer multi-pass FRAM-deposited alumin-um alloy samples were successfully prepared using a non-shoulder tool head.The material flow behavior and microstructure of the over-lapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition were studied using the hybrid 6061 and 5052 aluminum alloys.The results showed that a mechanical interlocking structure was formed between the adjacent layers and the adja-cent passes in the overlapped center area.Repeated friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone,which made the recrystallization degree in the left and right edge zones of the over-lapped zone the highest,followed by the overlapped center zone and the non-overlapped zone.The tensile strength of the overlapped zone exceeded 90%of that of the single-pass deposition sample.It is proved that although there are uneven grooves on the surface of the over-lapping area during multi-layer and multi-pass deposition,they can be filled by the flow of materials during the deposition of the next lay-er,thus ensuring the dense microstructure and excellent mechanical properties of the overlapping area.The multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.
