Based on the Sierpinski carpet and Menger sponge models, two categories of fractal models of rock and soil which are composed of the volume fractal model of pores, the volume fractal model of grains, pore-size or part...Based on the Sierpinski carpet and Menger sponge models, two categories of fractal models of rock and soil which are composed of the volume fractal model of pores, the volume fractal model of grains, pore-size or particle-size distribution fractal models are established and their relations are clarified in this paper. Through comparison and analysis, it is found that previous models can be unified by the two categories of fractal models, so the unified fractal models are formed. Experimental results presented by Katz indicate that the first category of fractal models can be used to express the fractal behavior of sandstone. A scanning electron microscope (SEM) will be used to study the microstructure of soft clay and it will be testified that the fractal behavior of soft clay suits the second category of fractal models.展开更多
Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of...Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.展开更多
Previous porosity models have been shown to be unable to accurately describe the pore-size distribution of rocks and soils.Three new porosity models are developed in this study.Pore-size distributions of soft clay and...Previous porosity models have been shown to be unable to accurately describe the pore-size distribution of rocks and soils.Three new porosity models are developed in this study.Pore-size distributions of soft clay and ecotypic revetment material were obtained using a scanning electron microscope(SEM)in two-dimensional space,and with the mercury intrusion method in three-dimensional space.The results show that the new porosity models are valid in predicting the accumulative porosity of rock and soil samples.Based on the new porosity models,a new microstructure soil consolidation model was developed and the error of the compression strain prediction was less than 0.007 under low pressure.Several models for soil water retention curve were founded,which in form comprise previous models developed by other researchers,and they may be more accurate than previous models because of the valid mean for determining the fractal dimension.In addition,we obtain an expression for the relationship between soil cohesion and the test specimen size,as well as between the bulk density of rocks and soils and the test specimen size.展开更多
Nanocarbon-based conductive membranes, especially carbon nanotube (CNT)-based membranes, have tremendous potential for wastewater treatment and water purification because of their excellent water permeability and sele...Nanocarbon-based conductive membranes, especially carbon nanotube (CNT)-based membranes, have tremendous potential for wastewater treatment and water purification because of their excellent water permeability and selectivity, as well as their electrochemically enhanced performance (e.g., improved antifouling ability). However, it remains challenging to prepare CNT membranes with high structural stability and high electrical conductivity. In this study, a highly electroconductive and structurally stable polyphenylene/CNT (PP/CNT) composite membrane was prepared by electropolymerizing biphenyl on a CNT hollow fiber membrane. The PP/CNT membrane showed 3.4 and 5.0 times higher electrical conductivity than pure CNT and poly(vinyl alcohol)/CNT (PVA/CNT) membranes, respectively. The structural stability of the membrane was superior to that of the pure CNT membrane and comparable to that of the PVA/CNT membrane. The membrane fouling was significantly alleviated under an electrical assistance of −2.0 V, with a flux loss of only 11.7% after 5 h filtration of humic acid, which is significantly lower than those of PP/CNT membranes without electro-assistance (56.8%) and commercial polyvinylidene fluoride (PVDF) membranes (64.1%). Additionally, the rejection of negatively charged pollutants (humic acid and sodium alginate) was improved by the enhanced electrostatic repulsion. After four consecutive filtration-cleaning cycle tests, the flux recovery rate after backwashing reached 97.2%, which was much higher than those of electricity-free PP/CNT membranes (67.0%) and commercial PVDF membranes (61.1%). This study offers insights into the preparation of stable conductive membranes for membrane fouling control in potential water treatment applications.展开更多
Nanofiltration(NF)has attracted increasing attention for wastewater treatment and potable water purification.However,the high-efficiency removal of micropollutants by NF membranes is a critical challenge.Owing to the ...Nanofiltration(NF)has attracted increasing attention for wastewater treatment and potable water purification.However,the high-efficiency removal of micropollutants by NF membranes is a critical challenge.Owing to the adsorption and subsequent diffusion,some weakly charged or uncharged micropollutants,such as bisphenol A(BPA),can pass through NF membranes,resulting in low removal rates.Herein,an effective strategy is proposed to enhance the BPA removal efficiency of a crosslinked polyaniline/carbon nanotube NF membrane by coupling the membrane with electro-assistance.The membrane exhibited a 31.9%removal rate for 5 mg/L BPA with a permeance of 6.8 L/(m2·h·bar),while the removal rate was significantly improved to 98.1%after applying a voltage of 2.0 V to the membrane.Furthermore,when BPA coexisted with humic acid,the membrane maintained 94%removal of total organic carbon and nearly 100%removal of BPA at 2.0 V over the entire filtration period.Compared to continuous voltage applied to the membrane,an intermittent voltage(2.0 V for 0.5 h with an interval of 3.5 h)could achieve comparable BPA removal efficiency,because of the combined effect of membrane adsorption and subsequent electrochemical oxidation.Density functional theory calculations and BPA oxidation process analyses suggested that BPA was adsorbed by two main interactions:π–πand hydrogen-bond interactions.The adsorbed BPA was further electro-degraded into small organic acids or mineralized to CO_(2) and H2O.This work demonstrates that NF membranes coupled with electro-assistance are feasible for improving the removal of weakly charged or uncharged micropollutants.展开更多
The gas-water two-phaseflow occurring as a result of fracturingfluidflowback phenomena is known to impact significantly the productivity of shale gas well.In this work,this two-phaseflow has been simulated in the framework...The gas-water two-phaseflow occurring as a result of fracturingfluidflowback phenomena is known to impact significantly the productivity of shale gas well.In this work,this two-phaseflow has been simulated in the framework of a hybrid approach partially relying on the embedded discrete fracture model(EDFM).This model assumes the region outside the stimulated reservoir volume(SRV)as a single-medium while the SRV region itself is described using a double-medium strategy which can account for thefluid exchange between the matrix and the micro-fractures.The shale gas adsorption,desorption,diffusion,gas slippage effect,fracture stress sensitivity,and capillary imbibition have been considered.The shale gas production,pore pressure distribution and water saturation distribution in the reservoir have been simulated.The influences of hydraulic fracture geometry and nonorthogonal hydraulic fractures on gas production have been determined and discussed accordingly.The simulation results show that the daily gas production has an upward and downward trend due to the presence of a large amount of fracturingfluid in the reservoir around the hydraulic fracture.The smaller the angle between the hydraulic fracture and the wellbore,the faster the daily production of shale gas wells decreases,and the lower the cumulative production.Nonplanar fractures can increase the control volume of hydraulic fractures and improve the production of shale gas wells.展开更多
This paper introduces a paradigm shift in atomic force microscope(AFM)scan control,leveraging an artificial intelligence(AI)-based controller.In contrast to conventional control methods,which either show a limited per...This paper introduces a paradigm shift in atomic force microscope(AFM)scan control,leveraging an artificial intelligence(AI)-based controller.In contrast to conventional control methods,which either show a limited performance,such as proportional integral differential(PID)control,or which purely focus on mathematical optimality as classical optimal control approaches,our proposed AI approach redefines the objective of control for achieving practical optimality.This presented AI controller minimizes the root-mean-square control deviations in routine scans by a factor of about 4 compared to PID control in the presented setup and also showcases a distinctive asymmetric response in complex situations,prioritizing the safety of the AFM tip and sample instead of the lowest possible control deviations.The development and testing of the AI control concept are performed on simulated AFM scans,demonstrating its huge potential.展开更多
This paper develops a WebGIS\|based GPS vehicle monitoring system with typical three\|tier application architecture of B/S pattern. It provides ordinary registered users with a valid and convenient means to get access...This paper develops a WebGIS\|based GPS vehicle monitoring system with typical three\|tier application architecture of B/S pattern. It provides ordinary registered users with a valid and convenient means to get access to real\|time GPS location information of certain moving vehicles at any place, and further offers a powerful tool for super users to manage user information and remotely monitor those vehicles and provide corresponding services timely if necessary. The system architecture, function modules, key technologies and application interfaces are given. Finally, the validity of our system is demonstrated in practical cases.展开更多
This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ent...This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ential settlement. Based on the study of ballastless track additional load and of vehicle, track, and bridge dynamic responses under different differential settlements, a control standard of differential settlement during operation is proposed preliminarily.展开更多
A dynamic triaxial instrument was used to study the effects of different concentrations of sodium chloride and stress amplitudes on the dynamic properties of an expansive soil under cyclic loading.In particular,four p...A dynamic triaxial instrument was used to study the effects of different concentrations of sodium chloride and stress amplitudes on the dynamic properties of an expansive soil under cyclic loading.In particular,four parameters were considered in such a parametric investigation,namely,hysteresis curve morphology characteristic non-closure degreeεp,the ratio of the short and long axisα,the slope of the long axis k and the enclosed area S.The results show that with an increase in the sodium chloride concentration,the soil particle double electric layer becomes thinner,the distance between soil particles decreases,and the whole sample becomes denser.Theεp-N,α-N and S–N relation curves all show a decreasing trend.The ratio of plastic deformation to total deformation grows with increasing the dynamic stress amplitude,and the curves show an upwards trend.The k-N relationship curve displays an increasing trend with the concentration and a general downwards trend as the dynamic stress amplitude is made higher.This also indicates that sodium chloride solutions can improve the engineering properties of expansive soil to a certain extent.With an increase in the vibration times N,the shape of the hysteretic curve becomes narrower,and the whole soil exhibits a cyclic strain hardening.With the help of an exponential function,a model is introduced to predict the relationship between the concentration and the hysteretic curve.展开更多
Graphene has attracted great interest in optoelectronics, owing to its high carrier mobility and broadband absorption. However, a graphene photodetector exhibits low photoresponsivity because of its weak light absorpt...Graphene has attracted great interest in optoelectronics, owing to its high carrier mobility and broadband absorption. However, a graphene photodetector exhibits low photoresponsivity because of its weak light absorption. In this work, we designed a graphene/MoSe_2 heterostructure photodetector, which exhibits photoresponse ranging from visible to near infrared and an ultrahigh photoresponsivity up to 1.3 × 104 A·W^(-1) at 550 nm. The electron–hole pairs are excited in a few-layered MoSe2 and separated by the built-in electric field. A large number of electrons shift to graphene, while the holes remain in the MoSe_2, which creates a photogating effect.展开更多
Rechargeable Al batteries(RAB)are promising candidates for safe and environmentally sustainable battery systems with low-cost investments.However,the currently used aluminum chloridebased electrolytes present a signif...Rechargeable Al batteries(RAB)are promising candidates for safe and environmentally sustainable battery systems with low-cost investments.However,the currently used aluminum chloridebased electrolytes present a significant challenge to commercialization due to their corrosive nature.Here,we report for the first time,a novel electrolyte combination for RAB based on aluminum trifluoromethanesulfonate(Al(OTf)_(3))with tetrabutylammonium chloride(TBAC)additive in diglyme.The presence of a mere 0.1 M of TBAC in the Al(OTf)_(3) electrolyte generates the charge carrying electrochemical species,which forms the basis of reaction at the electrodes.TBAC reduces the charge transfer resistance and the surface activation energy at the anode surface and also augments the dissociation of Al(OTf)_(3) to generate the solid electrolyte interphase components.Our electrolyte’s superiority directly translates into reduced anodic overpotential for cells that ran for 1300 cycles in Al plating/stripping tests,the longest cycling life reported to date.This unique combination of salt and additive is non-corrosive,exhibits a high flash point and is cheaper than traditionally reported RAB electrolyte combinations,which makes it commercially promising.Through this report,we address a major roadblock in the commercialization of RAB and inspire equivalent electrolyte fabrication approaches for other metal anode batteries.展开更多
Accurate metrology of extreme ultraviolet (EUV) photomask is a crucial task. In this paper, two different methods for reference EUV photomask metrology are compared. One is the critical dimension atomic force microsco...Accurate metrology of extreme ultraviolet (EUV) photomask is a crucial task. In this paper, two different methods for reference EUV photomask metrology are compared. One is the critical dimension atomic force microscopy (CD-AFM). In the measurements, the contribution of its AFM tip geometry is usually the dominant error source, as measured AFM images are the dilated results of measured structures by the AFM tip geometry. To solve this problem, a bottom-up approach has been applied in calibrating the (effective) AFM tip geometry where the result is traceably calibrated to the lattice constant of silicon crystals. The other is transmission electron microscopy (TEM). For achieving measurement traceability, structure features are measured in pairs in TEM images;thus the distance between the structure pair calibrated by a metrological AFM in prior can be applied to determine the magnification of the TEM image. In this study, selected photomask structures are calibrated by the CD-AFM, and then sample prepared and measured by high-resolution TEM nearly at the same location. The results are then compared. Of six feature groups compared, the results agree well within the measurement uncertainty, indicating excellent performance of the developed methodology. This research supports the development of a photomask standard, which is applied as a “reference ruler” with improved low measurement uncertainty in photomask fabs.展开更多
The effective identifications of important nodes in power grid are foundations of differentiated management and stable operation of power grid. However, the current studies on this field are not thorough enough. This ...The effective identifications of important nodes in power grid are foundations of differentiated management and stable operation of power grid. However, the current studies on this field are not thorough enough. This paper applies the model based on co-citation(MBCC)-hypertext induced topic selection(HITS) algorithm used in web page ranking to power grid and proposes an index to determine node importance of power grid from the perspectives of inflow and outflow power. MBCC-HITS algorithm is modified considering load, power source, and line flow comprehensively for the differences between Internet and power grid in this paper. Then a method for evaluating node importance is proposed using the modified algorithm. Lastly, the rationality and validity of the proposed method are verified by comparisons with other methods in case studies of IEEE 14-bus and 118-bus systems.展开更多
Nanometrology covers a wide range of metrology techniques for enabling characterization and measurement of nanomaterials,structures,components,devices,and systems at the nanoscale.Adequate nanometrology is key to inno...Nanometrology covers a wide range of metrology techniques for enabling characterization and measurement of nanomaterials,structures,components,devices,and systems at the nanoscale.Adequate nanometrology is key to innovations in nanotechnology and nanoscience,such as understanding the interaction mechanism between atoms,controlling nanomanufacturing processes,optimizing nanoscale products,as well as preventing nanotoxicity.Nanometrology is closely related to industry sectors such as semiconductor,automotive,nanomaterial,and nanophotonics,and has major economic,environmental,and social impacts on our economy and daily lives.展开更多
Tightly controlled extracellular matrix （ECM） homeostasis and remodeling is critical for normal organ homeostasis, wound healing and tissue repair. However, excessive or uncontrolled ECM deposition contributes to ab...Tightly controlled extracellular matrix （ECM） homeostasis and remodeling is critical for normal organ homeostasis, wound healing and tissue repair. However, excessive or uncontrolled ECM deposition contributes to aberrant homeostasis of tissue microenvironment in various inflam- matory diseases and tumors. Matricellular proteins are a set of structurally unrelated ECM proteins that do not exert a primary role in tissue architecture but have regulatory roles in embryonic development, tissue injury, inflammation and tumor progression. Two recent studies demonstrated that matricellular proteins in the ECM surrounding dormant tumor cells may determine the fate of tumor cells to remain qui- escent or undergo metastatic outgrowth. The identification of matricellular proteins in regulating ECM homeostasis and remodeling specific organ niches during tumor dormancy may provide potential novel extracellular targets for the development of therapeutic interventions against tumor dormancy.展开更多
The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanism...The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanisms.In this work,we report the synthesis of well-controlled vertically aligned Ni/NiO nanocomposites consisting of Ni nanoclusters embedded in NiO,which result in highly efficient electrocatalysts for overall water splitting.We show that such a high catalytic efficiency toward both the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)originates from a synergetic effect at Ni/NiO interfaces that significantly reduces the energy barrier for water dissociation,and favours the formation of reactive H*intermediates on the Ni side of the interface,and OH_(ads) on the NiO side of the interface.A study of water chemisorption based on near-ambient pressure photoelectron spectroscopy indicates that the abundant hetero-interfaces in Ni/NiO nanocomposite promote the dissociation of water with a three-fold increase in the surface concentration of OH_(ads) compared with pure NiO.Density functional theory calculations indicate that Ni/NiO interface leads to the reduction of the water dissociation energy barrier due to a high concentration of oxygen vacancies at NiO side of the interface,whereas the formation of highly active metallic Ni sites with an optimal value of Gibbs free energy of H*(ΔG_(H*)=−0.16 eV)owes to a favourable adjustment of the electron energetics at the interface,thus accelerating the overall electrochemical water splitting.展开更多
Metrological atomic force microscopes(Met.AFMs)with built-in interferometers are one of the main workhorses for versatile dimensional nanometrology.The interferometric nonlinearity error,particularly the high-order(i....Metrological atomic force microscopes(Met.AFMs)with built-in interferometers are one of the main workhorses for versatile dimensional nanometrology.The interferometric nonlinearity error,particularly the high-order(i.e.,3rd-and 4th-order)nonlinearity errors,is a dominant error source for further improving their metrology performance,which cannot be corrected using the conventional Heydemann correction method.To solve this problem,two new methods were developed.One uses a capacitive sensor embedded in the Met.AFM,and the other applies an external physical artifact with a flat surface.Both methods can be applied very conveniently and can effectively reduce the nonlinearity error.In this paper,the propagation of the(residual)nonlinearity error in step height calibrations is examined.Finally,the performance of the improved tool is verified in the calibration of a highly demanding industrial sample.For the measurements performed at 25 different positions and repeated six times,the standard deviation of the total 150 measured values is 0.08 nm,which includes the contributions from the reproducibility of the metrology tool and sample inhomogeneity.This research has significantly improved our dimensional nanometrology service.For instance,the extended measurement uncertainty(k=2)is reduced from 1.0 to 0.3 nm for the step height or etching depth calibrations.展开更多
Smaller and more complex three-dimensional periodic nanostructures are part of the next generation of integrated electronic circuits.Additionally,decreasing the dimensions of nanostructures increases the effect of lin...Smaller and more complex three-dimensional periodic nanostructures are part of the next generation of integrated electronic circuits.Additionally,decreasing the dimensions of nanostructures increases the effect of line-edge roughness on the performance of the nanostructures.Efficient methods for characterizing three-dimensional nanostructures are required for process control.Here,extreme-ultraviolet(EUV)scatterometry is exploited for the analysis of line-edge roughness from periodic nanostructures.In line with previous observations,differences are observed between line edge and line width roughness.The angular distribution of the diffuse scattering is an interplay of the line shape,the height of the structure,the roughness along the line,and the correlation between the lines.Unfortunately,existing theoretical methods for characterizing nanostructures using scatterometry do not cover all these aspects.Examples are shown here and the demands for future development of theoretical approaches for computing the angular distribution of the scattered X-rays are discussed.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 50778140)Special Research Foundation of Doctorial Subjects in Universities of China (Grant No. 20070497107)
文摘Based on the Sierpinski carpet and Menger sponge models, two categories of fractal models of rock and soil which are composed of the volume fractal model of pores, the volume fractal model of grains, pore-size or particle-size distribution fractal models are established and their relations are clarified in this paper. Through comparison and analysis, it is found that previous models can be unified by the two categories of fractal models, so the unified fractal models are formed. Experimental results presented by Katz indicate that the first category of fractal models can be used to express the fractal behavior of sandstone. A scanning electron microscope (SEM) will be used to study the microstructure of soft clay and it will be testified that the fractal behavior of soft clay suits the second category of fractal models.
基金supported by the National Natural Science Foundation of China(Nos.21276067 and 21676074)Programs of International S&T cooperation(No.2014DFR41110)
文摘Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.
基金supported by the National Natural Science Foundation of China(50778140)the Special Research Foundation of Doctorial Subjects in Universities of China(20070497107)
文摘Previous porosity models have been shown to be unable to accurately describe the pore-size distribution of rocks and soils.Three new porosity models are developed in this study.Pore-size distributions of soft clay and ecotypic revetment material were obtained using a scanning electron microscope(SEM)in two-dimensional space,and with the mercury intrusion method in three-dimensional space.The results show that the new porosity models are valid in predicting the accumulative porosity of rock and soil samples.Based on the new porosity models,a new microstructure soil consolidation model was developed and the error of the compression strain prediction was less than 0.007 under low pressure.Several models for soil water retention curve were founded,which in form comprise previous models developed by other researchers,and they may be more accurate than previous models because of the valid mean for determining the fractal dimension.In addition,we obtain an expression for the relationship between soil cohesion and the test specimen size,as well as between the bulk density of rocks and soils and the test specimen size.
基金supported by the National Key Research and Development Program of China(No.2020YFA0211001)the National Natural Science Foundation of China(No.22106017)+1 种基金the Fundamental Research Funds for the Central Universities(DUT2022TA04)the Programme of Introducing Talents of Discipline to Universities(China)(No.B13012).
文摘Nanocarbon-based conductive membranes, especially carbon nanotube (CNT)-based membranes, have tremendous potential for wastewater treatment and water purification because of their excellent water permeability and selectivity, as well as their electrochemically enhanced performance (e.g., improved antifouling ability). However, it remains challenging to prepare CNT membranes with high structural stability and high electrical conductivity. In this study, a highly electroconductive and structurally stable polyphenylene/CNT (PP/CNT) composite membrane was prepared by electropolymerizing biphenyl on a CNT hollow fiber membrane. The PP/CNT membrane showed 3.4 and 5.0 times higher electrical conductivity than pure CNT and poly(vinyl alcohol)/CNT (PVA/CNT) membranes, respectively. The structural stability of the membrane was superior to that of the pure CNT membrane and comparable to that of the PVA/CNT membrane. The membrane fouling was significantly alleviated under an electrical assistance of −2.0 V, with a flux loss of only 11.7% after 5 h filtration of humic acid, which is significantly lower than those of PP/CNT membranes without electro-assistance (56.8%) and commercial polyvinylidene fluoride (PVDF) membranes (64.1%). Additionally, the rejection of negatively charged pollutants (humic acid and sodium alginate) was improved by the enhanced electrostatic repulsion. After four consecutive filtration-cleaning cycle tests, the flux recovery rate after backwashing reached 97.2%, which was much higher than those of electricity-free PP/CNT membranes (67.0%) and commercial PVDF membranes (61.1%). This study offers insights into the preparation of stable conductive membranes for membrane fouling control in potential water treatment applications.
基金This work was supported by the National Key Research and Development Program of China(No.2020YFA0211001)the National Natural Science Foundation of China(Nos.22106017 and 52100074)+1 种基金the China Postdoctoral Science Foundationn(No.2022M710583)the Programme of Introducing Talents of Discipline to Universities(China)(No.B13012).
文摘Nanofiltration(NF)has attracted increasing attention for wastewater treatment and potable water purification.However,the high-efficiency removal of micropollutants by NF membranes is a critical challenge.Owing to the adsorption and subsequent diffusion,some weakly charged or uncharged micropollutants,such as bisphenol A(BPA),can pass through NF membranes,resulting in low removal rates.Herein,an effective strategy is proposed to enhance the BPA removal efficiency of a crosslinked polyaniline/carbon nanotube NF membrane by coupling the membrane with electro-assistance.The membrane exhibited a 31.9%removal rate for 5 mg/L BPA with a permeance of 6.8 L/(m2·h·bar),while the removal rate was significantly improved to 98.1%after applying a voltage of 2.0 V to the membrane.Furthermore,when BPA coexisted with humic acid,the membrane maintained 94%removal of total organic carbon and nearly 100%removal of BPA at 2.0 V over the entire filtration period.Compared to continuous voltage applied to the membrane,an intermittent voltage(2.0 V for 0.5 h with an interval of 3.5 h)could achieve comparable BPA removal efficiency,because of the combined effect of membrane adsorption and subsequent electrochemical oxidation.Density functional theory calculations and BPA oxidation process analyses suggested that BPA was adsorbed by two main interactions:π–πand hydrogen-bond interactions.The adsorbed BPA was further electro-degraded into small organic acids or mineralized to CO_(2) and H2O.This work demonstrates that NF membranes coupled with electro-assistance are feasible for improving the removal of weakly charged or uncharged micropollutants.
基金supported by the National Natural Science Foundation of China(Grant Nos.U19A2043 and 52174033)Natural Science Foundation of Sichuan Province(NSFSC)(No.2022NSFSC0971)the Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance.
文摘The gas-water two-phaseflow occurring as a result of fracturingfluidflowback phenomena is known to impact significantly the productivity of shale gas well.In this work,this two-phaseflow has been simulated in the framework of a hybrid approach partially relying on the embedded discrete fracture model(EDFM).This model assumes the region outside the stimulated reservoir volume(SRV)as a single-medium while the SRV region itself is described using a double-medium strategy which can account for thefluid exchange between the matrix and the micro-fractures.The shale gas adsorption,desorption,diffusion,gas slippage effect,fracture stress sensitivity,and capillary imbibition have been considered.The shale gas production,pore pressure distribution and water saturation distribution in the reservoir have been simulated.The influences of hydraulic fracture geometry and nonorthogonal hydraulic fractures on gas production have been determined and discussed accordingly.The simulation results show that the daily gas production has an upward and downward trend due to the presence of a large amount of fracturingfluid in the reservoir around the hydraulic fracture.The smaller the angle between the hydraulic fracture and the wellbore,the faster the daily production of shale gas wells decreases,and the lower the cumulative production.Nonplanar fractures can increase the control volume of hydraulic fractures and improve the production of shale gas wells.
基金funding from the EMPIR programme co-financed by the participating states and from the European Union’s Horizon 2020 research and innovation programme(20IND08‘MetExSPM’).
文摘This paper introduces a paradigm shift in atomic force microscope(AFM)scan control,leveraging an artificial intelligence(AI)-based controller.In contrast to conventional control methods,which either show a limited performance,such as proportional integral differential(PID)control,or which purely focus on mathematical optimality as classical optimal control approaches,our proposed AI approach redefines the objective of control for achieving practical optimality.This presented AI controller minimizes the root-mean-square control deviations in routine scans by a factor of about 4 compared to PID control in the presented setup and also showcases a distinctive asymmetric response in complex situations,prioritizing the safety of the AFM tip and sample instead of the lowest possible control deviations.The development and testing of the AI control concept are performed on simulated AFM scans,demonstrating its huge potential.
文摘This paper develops a WebGIS\|based GPS vehicle monitoring system with typical three\|tier application architecture of B/S pattern. It provides ordinary registered users with a valid and convenient means to get access to real\|time GPS location information of certain moving vehicles at any place, and further offers a powerful tool for super users to manage user information and remotely monitor those vehicles and provide corresponding services timely if necessary. The system architecture, function modules, key technologies and application interfaces are given. Finally, the validity of our system is demonstrated in practical cases.
基金supported by the National Nature Science Foundation of China (U1234206 and 61503311)+4 种基金support under the Railways Technology Development Plan of China Railway Corporation (2016X008-J)the Fundamental Research Funds for the Central Universities (2682015CX039)supported by the National United Engineering Laboratory of Integrated and Intelligent Transportation
文摘This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ential settlement. Based on the study of ballastless track additional load and of vehicle, track, and bridge dynamic responses under different differential settlements, a control standard of differential settlement during operation is proposed preliminarily.
文摘A dynamic triaxial instrument was used to study the effects of different concentrations of sodium chloride and stress amplitudes on the dynamic properties of an expansive soil under cyclic loading.In particular,four parameters were considered in such a parametric investigation,namely,hysteresis curve morphology characteristic non-closure degreeεp,the ratio of the short and long axisα,the slope of the long axis k and the enclosed area S.The results show that with an increase in the sodium chloride concentration,the soil particle double electric layer becomes thinner,the distance between soil particles decreases,and the whole sample becomes denser.Theεp-N,α-N and S–N relation curves all show a decreasing trend.The ratio of plastic deformation to total deformation grows with increasing the dynamic stress amplitude,and the curves show an upwards trend.The k-N relationship curve displays an increasing trend with the concentration and a general downwards trend as the dynamic stress amplitude is made higher.This also indicates that sodium chloride solutions can improve the engineering properties of expansive soil to a certain extent.With an increase in the vibration times N,the shape of the hysteretic curve becomes narrower,and the whole soil exhibits a cyclic strain hardening.With the help of an exponential function,a model is introduced to predict the relationship between the concentration and the hysteretic curve.
基金financially supported by the National Natural Science Foundation of China(No.61575010)the Natural Science Foundation of Beijing(No.4162016)+1 种基金the Beijing Municipal Science and Technology Commission(No.Z151100003315018)the Beijing Nova Program(No.Z141109001814053)
文摘Graphene has attracted great interest in optoelectronics, owing to its high carrier mobility and broadband absorption. However, a graphene photodetector exhibits low photoresponsivity because of its weak light absorption. In this work, we designed a graphene/MoSe_2 heterostructure photodetector, which exhibits photoresponse ranging from visible to near infrared and an ultrahigh photoresponsivity up to 1.3 × 104 A·W^(-1) at 550 nm. The electron–hole pairs are excited in a few-layered MoSe2 and separated by the built-in electric field. A large number of electrons shift to graphene, while the holes remain in the MoSe_2, which creates a photogating effect.
基金the financial support from Agency for Science, Technology and Research (Central Research Fund Award)
文摘Rechargeable Al batteries(RAB)are promising candidates for safe and environmentally sustainable battery systems with low-cost investments.However,the currently used aluminum chloridebased electrolytes present a significant challenge to commercialization due to their corrosive nature.Here,we report for the first time,a novel electrolyte combination for RAB based on aluminum trifluoromethanesulfonate(Al(OTf)_(3))with tetrabutylammonium chloride(TBAC)additive in diglyme.The presence of a mere 0.1 M of TBAC in the Al(OTf)_(3) electrolyte generates the charge carrying electrochemical species,which forms the basis of reaction at the electrodes.TBAC reduces the charge transfer resistance and the surface activation energy at the anode surface and also augments the dissociation of Al(OTf)_(3) to generate the solid electrolyte interphase components.Our electrolyte’s superiority directly translates into reduced anodic overpotential for cells that ran for 1300 cycles in Al plating/stripping tests,the longest cycling life reported to date.This unique combination of salt and additive is non-corrosive,exhibits a high flash point and is cheaper than traditionally reported RAB electrolyte combinations,which makes it commercially promising.Through this report,we address a major roadblock in the commercialization of RAB and inspire equivalent electrolyte fabrication approaches for other metal anode batteries.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘Accurate metrology of extreme ultraviolet (EUV) photomask is a crucial task. In this paper, two different methods for reference EUV photomask metrology are compared. One is the critical dimension atomic force microscopy (CD-AFM). In the measurements, the contribution of its AFM tip geometry is usually the dominant error source, as measured AFM images are the dilated results of measured structures by the AFM tip geometry. To solve this problem, a bottom-up approach has been applied in calibrating the (effective) AFM tip geometry where the result is traceably calibrated to the lattice constant of silicon crystals. The other is transmission electron microscopy (TEM). For achieving measurement traceability, structure features are measured in pairs in TEM images;thus the distance between the structure pair calibrated by a metrological AFM in prior can be applied to determine the magnification of the TEM image. In this study, selected photomask structures are calibrated by the CD-AFM, and then sample prepared and measured by high-resolution TEM nearly at the same location. The results are then compared. Of six feature groups compared, the results agree well within the measurement uncertainty, indicating excellent performance of the developed methodology. This research supports the development of a photomask standard, which is applied as a “reference ruler” with improved low measurement uncertainty in photomask fabs.
基金supported by State Grid Technology Project(No.GY71-14-075)
文摘The effective identifications of important nodes in power grid are foundations of differentiated management and stable operation of power grid. However, the current studies on this field are not thorough enough. This paper applies the model based on co-citation(MBCC)-hypertext induced topic selection(HITS) algorithm used in web page ranking to power grid and proposes an index to determine node importance of power grid from the perspectives of inflow and outflow power. MBCC-HITS algorithm is modified considering load, power source, and line flow comprehensively for the differences between Internet and power grid in this paper. Then a method for evaluating node importance is proposed using the modified algorithm. Lastly, the rationality and validity of the proposed method are verified by comparisons with other methods in case studies of IEEE 14-bus and 118-bus systems.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘Nanometrology covers a wide range of metrology techniques for enabling characterization and measurement of nanomaterials,structures,components,devices,and systems at the nanoscale.Adequate nanometrology is key to innovations in nanotechnology and nanoscience,such as understanding the interaction mechanism between atoms,controlling nanomanufacturing processes,optimizing nanoscale products,as well as preventing nanotoxicity.Nanometrology is closely related to industry sectors such as semiconductor,automotive,nanomaterial,and nanophotonics,and has major economic,environmental,and social impacts on our economy and daily lives.
文摘Tightly controlled extracellular matrix （ECM） homeostasis and remodeling is critical for normal organ homeostasis, wound healing and tissue repair. However, excessive or uncontrolled ECM deposition contributes to aberrant homeostasis of tissue microenvironment in various inflam- matory diseases and tumors. Matricellular proteins are a set of structurally unrelated ECM proteins that do not exert a primary role in tissue architecture but have regulatory roles in embryonic development, tissue injury, inflammation and tumor progression. Two recent studies demonstrated that matricellular proteins in the ECM surrounding dormant tumor cells may determine the fate of tumor cells to remain qui- escent or undergo metastatic outgrowth. The identification of matricellular proteins in regulating ECM homeostasis and remodeling specific organ niches during tumor dormancy may provide potential novel extracellular targets for the development of therapeutic interventions against tumor dormancy.
基金the National Natural Science Foundation of China(21872116)F.E.Oropeza and V.A.de la Peña O’Shea are grateful for the funding supported by the EU(ERC CoG HyMAP 648319)and Spanish AEI(NyMPhA PID2019-106315RB-I00)+3 种基金Also,this work has been funded by the regional government of Comunidad de Madrid and European Structural Funds through their financial support to FotoArt-CM project(S2018/NMT-4367)Besides,Fundación Ramon Areces funded this work though ArtLeaf project.Kelvin H.L.Zhang also acknowledge the Sino-German Mobility Program(M-0377)SuperSTEM is the National Research Facility for Advanced Electron Microscopy,funded from the Engineering and Physics Research Council(EPSRC)M.Bugnet is grateful to the SuperSTEM Laboratory for microscope access,and to the School of Chemical and Process Engineering at the University of Leeds for a visiting associate professorship and financial support.
文摘The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanisms.In this work,we report the synthesis of well-controlled vertically aligned Ni/NiO nanocomposites consisting of Ni nanoclusters embedded in NiO,which result in highly efficient electrocatalysts for overall water splitting.We show that such a high catalytic efficiency toward both the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)originates from a synergetic effect at Ni/NiO interfaces that significantly reduces the energy barrier for water dissociation,and favours the formation of reactive H*intermediates on the Ni side of the interface,and OH_(ads) on the NiO side of the interface.A study of water chemisorption based on near-ambient pressure photoelectron spectroscopy indicates that the abundant hetero-interfaces in Ni/NiO nanocomposite promote the dissociation of water with a three-fold increase in the surface concentration of OH_(ads) compared with pure NiO.Density functional theory calculations indicate that Ni/NiO interface leads to the reduction of the water dissociation energy barrier due to a high concentration of oxygen vacancies at NiO side of the interface,whereas the formation of highly active metallic Ni sites with an optimal value of Gibbs free energy of H*(ΔG_(H*)=−0.16 eV)owes to a favourable adjustment of the electron energetics at the interface,thus accelerating the overall electrochemical water splitting.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘Metrological atomic force microscopes(Met.AFMs)with built-in interferometers are one of the main workhorses for versatile dimensional nanometrology.The interferometric nonlinearity error,particularly the high-order(i.e.,3rd-and 4th-order)nonlinearity errors,is a dominant error source for further improving their metrology performance,which cannot be corrected using the conventional Heydemann correction method.To solve this problem,two new methods were developed.One uses a capacitive sensor embedded in the Met.AFM,and the other applies an external physical artifact with a flat surface.Both methods can be applied very conveniently and can effectively reduce the nonlinearity error.In this paper,the propagation of the(residual)nonlinearity error in step height calibrations is examined.Finally,the performance of the improved tool is verified in the calibration of a highly demanding industrial sample.For the measurements performed at 25 different positions and repeated six times,the standard deviation of the total 150 measured values is 0.08 nm,which includes the contributions from the reproducibility of the metrology tool and sample inhomogeneity.This research has significantly improved our dimensional nanometrology service.For instance,the extended measurement uncertainty(k=2)is reduced from 1.0 to 0.3 nm for the step height or etching depth calibrations.
基金funding from the Electronic Component Systems for European Leadership Joint Undertaking under grant agreement No 826589|MADEin4This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme and The Netherlands,France,Belgium,Germany,Czech Republic,Austria,Hungary,and IsraelOpen Access funding enabled and organized by Projekt DEAL.
文摘Smaller and more complex three-dimensional periodic nanostructures are part of the next generation of integrated electronic circuits.Additionally,decreasing the dimensions of nanostructures increases the effect of line-edge roughness on the performance of the nanostructures.Efficient methods for characterizing three-dimensional nanostructures are required for process control.Here,extreme-ultraviolet(EUV)scatterometry is exploited for the analysis of line-edge roughness from periodic nanostructures.In line with previous observations,differences are observed between line edge and line width roughness.The angular distribution of the diffuse scattering is an interplay of the line shape,the height of the structure,the roughness along the line,and the correlation between the lines.Unfortunately,existing theoretical methods for characterizing nanostructures using scatterometry do not cover all these aspects.Examples are shown here and the demands for future development of theoretical approaches for computing the angular distribution of the scattered X-rays are discussed.
