The Kandi basin is located in northeast Benin (West Africa). This study is focused on the estimation of water fluxes exchanged between the river Niger (and its tributaries) and the transboundary Iullemeden Aquifer Sys...The Kandi basin is located in northeast Benin (West Africa). This study is focused on the estimation of water fluxes exchanged between the river Niger (and its tributaries) and the transboundary Iullemeden Aquifer System. In that framework, an innovative approach based on the application of the Bayesian Mixing Model (MixSIAR) analysis on water isotopes (oxygen-18, deuterium and tritium) was performed. Moreover, to assess the relevance of the model outputs, Pearson’s correlation and Principal Component Analysis (PCA) have been done. A complex relationship between surface water and groundwater has been found. Sixty percent (60%) of groundwater samples are made of more than 70% river water and rainwater;while 31.25% of surface water samples are made of about 84% groundwater. To safeguard sustainable water resources for the well-being of the local communities, surface water and groundwater must be managed as a unique component in the Kandi basin.展开更多
Interactions involving chemical reagents,solid particles,gas bubbles,liquid droplets,and solid surfaces in complex fluids play a vital role in many engineering processes,such as froth flotation,emulsion and foam forma...Interactions involving chemical reagents,solid particles,gas bubbles,liquid droplets,and solid surfaces in complex fluids play a vital role in many engineering processes,such as froth flotation,emulsion and foam formation,adsorption,and fouling and anti-fouling phenomena.These interactions at the molecular,nano-,and micro scale significantly influence and determine the macroscopic performance and efficiency of related engineering processes.Understanding the intermolecular and surface interactions in engineering processes is of both fundamental and practical importance,which not only improves production technologies,but also provides valuable insights into the development of new materials.In this review,the typical intermolecular and surface interactions involved in various engineering processes,including Derjaguin–Landau–Verwey–Overbeek(DLVO)interactions(i.e.,van der Waals and electrical doublelayer interactions)and non-DLVO interactions,such as steric and hydrophobic interactions,are first introduced.Nanomechanical techniques such as atomic force microscopy and surface forces apparatus for quantifying the interaction forces of molecules and surfaces in complex fluids are briefly introduced.Our recent progress on characterizing the intermolecular and surface interactions in several engineering systems are reviewed,including mineral flotation,petroleum engineering,wastewater treatment,and energy storage materials.The correlation of these fundamental interaction mechanisms with practical applications in resolving engineering challenges and the perspectives of the research field have also been discussed.展开更多
Based on the interface shear tests,the macro-and meso-mechanical behaviors of interaction between coral sand and different structure surfaces are studied,in which CCD camera is used to capture digital images to analyz...Based on the interface shear tests,the macro-and meso-mechanical behaviors of interaction between coral sand and different structure surfaces are studied,in which CCD camera is used to capture digital images to analyze the evolution of the interaction band and a particle analysis apparatus is applied to studying the distribution characteristics of particle morphology.This study proposes four-stage evolution process based on the shear stress−strain curve.During the shear process,coral sand particles slide and rotate within the interaction band,causing the changes in shear stress and vertical displacement.In addition,the effects of structure surface roughness on shear strength,volume change and particle breakage are illustrated that the greater the roughness of slabs is,the larger the shear stress is,the more obvious the contraction effect is and the more the particles break.Furthermore,the change in particle’s 3D morphology during the breakage will change not only their size but also other morphological characteristics with convergence and self-organization.展开更多
Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)t...Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)transference number of these electrolytes significantly increase the internal resistance and overpotential of the battery.Here,we introduce Gd-doped CeO_(2) nanowires with large surface area and rich surface oxygen vacancies to the polymer electrolyte to increase the interaction between Gd-doped CeO_(2) nanowires and polymer electrolytes,which promotes the Li-salt dissociation and increases the concentration of mobile Li ions in the composite polymer electrolytes.The optimized composite polymer electrolyte has a high Li-ion conductivity of 5×10^(-4)4 S cm^(-1) at 30℃ and a large Li+transference number of 0.47.Moreover,the composite polymer electrolytes have excellent compatibility with the metallic lithium anode and high-voltage LiNi_(0.8)Mn _(0.1)Co_(0.1)O_(2)(NMC)cathode,providing the stable cycling of all-solid-state batteries at high current densities.展开更多
Grinding and flotation processes are often studied independently, despite the well-established grinding influence on flotation performance, which affects not only particle size and thus liberation but also shape and l...Grinding and flotation processes are often studied independently, despite the well-established grinding influence on flotation performance, which affects not only particle size and thus liberation but also shape and leads to complex changes in pulp chemistry affecting the particle surface properties relevant for selective bubble attachment. Yet, no study jointly investigated these possible causes and many are limited to single mineral flotation. We relate grinding conditions to changes in pulp chemistry and particle surface properties and assess their impact on upgrading. We studied three non-sulfide ores with different feed grades and valuables: scheelite, apatite, and fluorite. These were dry-, wet-, and wet conditionedground before flotation in a laboratory mechanical cell. Results were evaluated with bulk-and particle-specific methodologies. The selectivity of the process is higher after dry grinding for the fluorite and apatite ores and irrelevant for the scheelite ore. Variations in flotation kinetics of individual particles associated to their size and shape are not sufficient to explain these results. The higher concentration of Ca2+and Mg2+observed in the pulp after wet grinding, altering particle surface properties, better explains the phenomenon. Additionally, we demonstrate how particle shape impacts are system specific and related to both entrainment and true flotation.展开更多
We have studied the ionization of Rydberg hydrogen atom near a metal surface with a semiclassical analysis of photoionization microscopy. Interference patterns of the electron radial distribution are calculated at dif...We have studied the ionization of Rydberg hydrogen atom near a metal surface with a semiclassical analysis of photoionization microscopy. Interference patterns of the electron radial distribution are calculated at different scaled energies above the classical saddle point and at various atom surface distances. We find that different types of trajecto- ries contribute predominantly to different manifolds in a certain interference pattern. As the scaled energy increases, the structure of the interference pattern evolves smoothly and more types of trajectories emerge. As the atom approaches the metal surface closer, there are more types of trajectories contributing to the interference pattern as well. When the Rydberg atom comes very close to the metal surface or the scaled energy approaches the zero field ionization energy, the potential induced by the metal surface will make atomic system chaotic. The results also show that atoms near a metal surface exhibit similar properties like the atoms in the parallel electric and magnetic fields.展开更多
Fertilizer input for agricultural food production, as well as the discharge of domestic and industrial water pollutants, increases pressures on locally scarce and vulnerable water resources in the North China Plain. I...Fertilizer input for agricultural food production, as well as the discharge of domestic and industrial water pollutants, increases pressures on locally scarce and vulnerable water resources in the North China Plain. In order to：（a） understand pollutant exchange between surface water and groundwater,（b） quantify nutrient loadings, and（c） identify major nutrient removal pathways by using qualitative and quantitative methods, including the geochemical model PHREEQC） a one-year study at a wheat（Triticum aestivum L.） and maize（Zea mays L.） double cropping system in the Baiyang Lake area in Hebei Province, China, was undertaken. The study showed a high influence of low-quality surface water on the shallow aquifer. Major inflowing pollutants into the aquifer were ammonium and nitrate via inflow from the adjacent Fu River（up to 29.8 mg/L NH4-N and 6.8 mg/L NO3-N）, as well as nitrate via vertical transport from the field surface（up to 134.8 mg/L NO3-N in soil water）. Results from a conceptual model show an excess nitrogen input of about 320 kg/ha/a. Nevertheless,both nitrogen species were only detected at low concentrations in shallow groundwater,averaging at 3.6 mg/L NH4-N and 1.8 mg/L NO3-N. Measurement results supported by PHREEQC-modeling indicated cation exchange, denitrification, and anaerobic ammonium oxidation coupled with partial denitrification as major nitrogen removal pathways. Despite the current removal capacity, the excessive nitrogen fertilization may pose a future threat to groundwater quality. Surface water quality improvements are therefore recommended in conjunction with simultaneous monitoring of nitrate in the aquifer, and reduced agricultural N-inputs should be considered.展开更多
An analytical simulation based on a new model incorporating surface interaction is conducted to study the slip phenomenon in the Couette flow at different scales. The velocity profile is calculated by taking account o...An analytical simulation based on a new model incorporating surface interaction is conducted to study the slip phenomenon in the Couette flow at different scales. The velocity profile is calculated by taking account of the micro-force between molecules and macro-force from the viscous shearing effect, as they contribute to the achieve- ment of the slip length. The calculated results are compared with those obtained from the molecular dynamics simulation, showing an excellent agreement. Further, the effect of the shear rate on the slip is investigated. The results can well predict the fluid flow behaviors on a solid substrate, but has to be proved by experiment.展开更多
In this work,an improved understanding of electron sheath theory is provided using both fluid and kinetic approaches while elaborating on their implications for plasma–surface interactions.A fluid model is proposed c...In this work,an improved understanding of electron sheath theory is provided using both fluid and kinetic approaches while elaborating on their implications for plasma–surface interactions.A fluid model is proposed considering the electron presheath structure,avoiding the singularity in electron sheath Child–Langmuir law which overestimates the sheath potential.Subsequently,a kinetic model of electron sheath is established,showing considerably different sheath proflles in respect to the fluid model due to non-Maxwellian electron velocity distribution function and flnite ion temperature.The kinetic model is then further generalized and involves a more realistic truncated ion velocity distribution function.It is demonstrated that such a distribution function yields a super-thermal electron sheath whose entering velocity at the sheath edge is greater than the Bohm criterion prediction.Furthermore,an attempt is made to describe the electron presheath–sheath coupling within the kinetic framework,showing a necessary compromise between a realistic sheath entrance and the inclusion of kinetic effects.Finally,the secondary electron emissions induced by sheath-accelerated plasma electrons in an electron sheath are analysed and the influence of backscattering is discussed.展开更多
Based on the crystal structures of two cucurbit[6]uril/calix[n]arene-based supramolecular frameworks reported by Long and co-workers,we further investigated the interactions of cucurbit[6]uril with 4-sulfocalix[4]aren...Based on the crystal structures of two cucurbit[6]uril/calix[n]arene-based supramolecular frameworks reported by Long and co-workers,we further investigated the interactions of cucurbit[6]uril with 4-sulfocalix[4]arene and 4-sulfocalix[6]arene using ^(1)H NMR spectroscopy and isothermal titration calorimetry(ITC),respectively.Moreover,solid fluorescent materials were prepared via the adsorption of fluorescent dyes by these porous supramolecular frameworks,which exhibit a selective response to certain volatile organic compounds.展开更多
Curcurbit[n]uril(Q[n])-based supramolecular frameworks(QSFs) constructed from the outer surface interaction of Q[n]s(OSIQ) have the characteristic of simplicity,diversity and modulability.Their simplicity is reflected...Curcurbit[n]uril(Q[n])-based supramolecular frameworks(QSFs) constructed from the outer surface interaction of Q[n]s(OSIQ) have the characteristic of simplicity,diversity and modulability.Their simplicity is reflected in their simple composition and preparation methods used for QSFs.The diversity of supramolecular organic frameworks(SOFs) is reflected in the synthesis methods and structural characteristics of the as-obtained QSFs,as well as the variety of structural directing agents and basic building blocks used to prepare QSFs.The modulability is reflected by the controllable channel size in the QSFs,which can be adjusted using different sizes of Q[n]s.In this work,the first re ported cucurbituril Q[6]was selected as the basic building block and three Q[6]-based su p ramolecular frameworks were obtained from aqueous HCl solutions in the presence of [CdCl_(4)]^(2-)respectively.The OSIQs are the main driving forces for the formation of these frameworks.This study shows the diversity of the QSFs.展开更多
Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play...Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play critical roles in biogeochemical transformations in STEs,limited information is available about how their community dynamics interact with hydrological,geochemical and environmental characteristics in STEs.Here,we studied bacterial and archaeal diversities and distributions with 16S rRNA-based Illumina MiSeq sequencing technology between surface water and groundwater in a karstic STE.Principal-coordinate analysis found that the bacterial and archaeal communities in the areas where algal blooms occurred were significantly separated from those in other stations without algal bloom occurrence.Canonical correspondence analysis showed that nutrients and salinity can explain the patterns of bacterial and archaeal community dynamics.The results suggest that hydrological,geochemical and environmental characteristics between surface water and groundwater likely control the bacterial and archaeal diversities and distributions in STEs.Furthermore,we found that some key species can utilize terrestrial pollutants such as nitrate and ammonia in STEs,indicating that these species(e.g.,Nitrosopumilus maritimus,Limnohabitans parvus and Simplicispira limi)may be excellent candidates for in situ degradation/remediation of coastal groundwater contaminations concerned with the nitrate and ammonia.Overall,this study reveals the coupling relationship between the microbial communities and hydrochemical environments in STEs,and provides a perspective of in situ degradation/remediation for coastal groundwater quality management.展开更多
The dynamics of the scattering processes of diatomic molecules from metal surfaces has been studied with different theoretical approaches. Modified LEPS (London-Eyring-Polanyi-Sato) potential surfaces for several diat...The dynamics of the scattering processes of diatomic molecules from metal surfaces has been studied with different theoretical approaches. Modified LEPS (London-Eyring-Polanyi-Sato) potential surfaces for several diatomie molecule-surface systems have been constructed and examined for the dynamic study. The surfaces are treated as rigid but corrugated. The potential parameters are adjusted to produce reliable potential hypersurfaces. Molecular dissociation, diffraction, adsorption and consequent desorption in the scattering processes have been observed through quasiclassieal trajectory calculations. The significance of the effective corrugation of the potential surfaces has been evaluated in calculating the dissociation and adsorption probabilities. Vibration-rotation-translation energy transfer in the inelastic scattering is investigated to understand the mechanism of selective adsorptions mediated through vibrational or rotational degrees of freedom. We have carried out quantum mechanical calculations to obtain the rotational and vibrational transition probabilities. Relative importance of rotational and vibrational transitions for each adsorbed state with respect to incidence energy has been carefully examined to determine the dominant factor which causes the adsorbed state. The results show that vibration mediation is an essential factor to the selective adsorption especially in the ease of higher incidence energies.展开更多
Environment isotopes(δ18O andδ2H)and Cl/Br ratios in surface water and groundwater are combined to investigate arsenic mobilization in aquifer system of the Jianghan Plain.The groundwater has relatively high arsenic...Environment isotopes(δ18O andδ2H)and Cl/Br ratios in surface water and groundwater are combined to investigate arsenic mobilization in aquifer system of the Jianghan Plain.The groundwater has relatively high arsenic concentrations,ranging from 3.6 to 1055.3μg/L with an average of 102.2μg/L,which exceeds China’s drinking water standard(10μg/L).The arsenic content of surface water samples is quite low with the range of 6.0–14.3μg/L,averaging 9.5μg/L.δ18O andδ2H values for surface water and groundwater samples plot close to the local meteoric water line(LMWL),reflecting their meteoric origin;a subset of the samples(shallow wells,10 m)shows a shift to LMWL,commensurate with mixing with surface water and evaporation.The correlations betweenδ18O values and Cl concentration and Cl/Br ratios as well as arsenic concentration demonstrated that surface water and groundwater interactions,including active exchange between river/pond water and groundwater and vertical infiltration from agricultural and aquacultural soils,were dominated processes affecting arsenic mobilization in shallow groundwater system and lateral recharge was the main process controlling arsenic behavior in deep groundwater system.The results of this study will be beneficial to understanding the causes of arsenic mobilization in Jianghan groundwaters at different depths.展开更多
Na-rich birnessite（NRB） was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion（NH＋4） from aqueous solution.In order to demonstrate the adsorption perf...Na-rich birnessite（NRB） was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion（NH＋4） from aqueous solution.In order to demonstrate the adsorption performance of the synthesized material,the effects of contact time,pH,initial ammonium ion concentration,and temperature were investigated.Adsorption kinetics showed that the adsorption behavior followed the pseudo second-order kinetic model.The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption models and the model parameters were evaluated.The monolayer adsorption capacity of the adsorbent,as obtained from the Langmuir isotherm,was 22.61 mg NH＋4-N/g at283 K.Thermodynamic analyses showed that the adsorption was spontaneous and that it was also a physisorption process.Our data revealed that the higher NH＋4adsorption capacity could be primarily attributed to the water absorption process and electrostatic interaction.Particularly,the high surface hydroxyl-content of NRB enables strong interactions with ammonium ion.The results obtained in this study illustrate that the NRB is expected to be an effective and economically viable adsorbent for ammonium ion removal from aqueous system.展开更多
The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India.It also aims to define depth to granitoid and structural elements which traverse the selected...The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India.It also aims to define depth to granitoid and structural elements which traverse the selected area.Magnetic data(n=84)measured,processed and interpreted as qualitative and quantitatively.The results of total magnetic intensities indicate that the area is composed of linear magnetic lows trending NE-SW direction and circular to semi-circular causative bodies.The magnetic values ranged from-137 nT to 2345 nT with a mean of 465 nT.Reduction to equator shows significant shifting of causative bodies in the southern and northern directions.Analytical signal map shows exact boundary of granitic bodies.Cosine directional filter has brought out structural element trending NE-SW direction.Results of individual profile brought to light structurally weak zone between 90 m and 100 m in all the profile lines.Sudden decrease of magnetic values from 2042 nT to 126 nT noticed in profile line 6 between 20 m and 30 m indicates fault occurrence.Magnetic breaks obtained from these maps were visualized,interpreted and identified two suitable sites for open and bore well.Radially averaged power spectrum estimates depth of shallow and deep sources in 5 m and 50 m,respectively.Euler method has also been applied to estimate depth of granitoid and structural elements using structural indexes 0,1,2,and 3 and found depth ranges from<10 m to>90 m.Study indicates magnetic method is one of the geophysical methods suitable for groundwater exploration and site selection for open and borewells.展开更多
The nerves of the peripheral nervous system are not able to effectively regenerate in cases of severe neural injury.This can result in debilitating consequences,including morbidity and lifelong impairments affecting t...The nerves of the peripheral nervous system are not able to effectively regenerate in cases of severe neural injury.This can result in debilitating consequences,including morbidity and lifelong impairments affecting the quality of the patient’s life.Recent findings in neural tissue engineering have opened promising avenues to apply fibrous tissue-engineered scaffolds to promote tissue regeneration and functional recovery.These scaffolds,known as neural scaffolds,are able to improve neural regeneration by playing two major roles,namely,by being a carrier for transplanted peripheral nervous system cells or biological cues and by providing structural support to direct growing nerve fibers towards the target area.However,successful implementation of scaffold-based therapeutic approaches calls for an appropriate design of the neural scaffold structure that is capable of up-and down-regulation of neuron-scaffold interactions in the extracellular matrix environment.This review discusses the main challenges that need to be addressed to develop and apply fibrous tissue-engineered scaffolds in clinical practice.It describes some promising solutions that,so far,have shown to promote neural cell adhesion and growth and a potential to repair peripheral nervous system injuries.展开更多
Since the outer surface interaction of Q[n]s (OSIQ, including self-, anion- and aromatic-induced OSIQs) was proposed in 2014, it has become the most important research area in our group to construct various Q[n]-based...Since the outer surface interaction of Q[n]s (OSIQ, including self-, anion- and aromatic-induced OSIQs) was proposed in 2014, it has become the most important research area in our group to construct various Q[n]-based supramolecular frameworks via the OSIQ strategy. Herein, we report a novel supramolecular framework constructed using cucurbit[8]uril (Q[8]) and 4-sulfocalix[6]arene (SC[6]A). This Q[8]/SC[6]A-based supramolecular framework is a product via the perfect combination of self-, anion- and aromatic-induced OSIQs. This framework has the characteristics of easy preparation and high stability with the most important feature being the sequence selective capture of specific metal cations, such as common alkali- and alkaline earth metal ions, and renewability. Thus, this framework may be used in seawater desalination, potassium ion enrichment, radioactive cesium ion pollution source treatment, Gruinard's treatment or water softening and other applications.展开更多
In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the ...In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the erosion. However, the mutual influences between wind erosion and water erosion have not been fully understood. This research used a wind tunnel and two rainfall simulators and simulated two rounds of alternations between wind erosion and water erosion（i.e., 1^（st） wind erosion–1^（st） water erosion and 2^（nd） wind erosion–2^（nd） water erosion） on three slopes（5°, 10°, and 15°） with six wind speeds（0, 9, 11, 13, 15, and 20 m/s） and five rainfall intensities（0, 30, 45, 60, and 75 mm/h）. The objective was to analyze the influences of wind erosion on succeeding water erosion. Results showed that the effects of wind erosion on water erosion were not the same in the two rounds of tests. In the 1^（st） round of tests, wind erosion first restrained and then intensified water erosion mostly because the blocking effect of wind-sculpted micro-topography on surface flow was weakened with the increase in slope. In the 2^（nd） round of tests, wind erosion intensified water erosion on beds with no rills at gentle slopes and low rainfall intensities or with large-size rills at steep slopes and high rainfall intensities. Wind erosion restrained water erosion on beds with small rills at moderate slopes and moderate rainfall intensities. The effects were mainly related to the fine grain layer, rills and slope of the original bed in the 2^（nd） round of tests. The findings can deepen our understanding of complex erosion resulted from a combination of wind and water actions and provide scientific references to regional soil and water conservation.展开更多
Composites of carbon aerogel and graphite oxide（GO） were synthesized using a self-assembly method based on dispersive forces. Their surface was modified by treatment in hydrogen sulfide at 650 and800 ℃. The samples...Composites of carbon aerogel and graphite oxide（GO） were synthesized using a self-assembly method based on dispersive forces. Their surface was modified by treatment in hydrogen sulfide at 650 and800 ℃. The samples obtained were characterized by adsorption of nitrogen, TA-MS, XPS, potentiometric titration, and HRTEM and tested as catalysts for oxygen reduction reactions（ORR） in an alkaline medium.The synergistic effect of the composite（electrical conductivity, porosity and surface chemistry） leads to a good ORR catalytic activity. The onset potential for the composite of carbon aerogel heated at 800 ℃ is shifted to a more positive value and the number of electron transfer was 2e-at the potential 0.68 V versus RHE and it increased to 4e-with an increase in the negative values of the potential. An excellent tolerance to methanol crossover was also recorded.展开更多
文摘The Kandi basin is located in northeast Benin (West Africa). This study is focused on the estimation of water fluxes exchanged between the river Niger (and its tributaries) and the transboundary Iullemeden Aquifer System. In that framework, an innovative approach based on the application of the Bayesian Mixing Model (MixSIAR) analysis on water isotopes (oxygen-18, deuterium and tritium) was performed. Moreover, to assess the relevance of the model outputs, Pearson’s correlation and Principal Component Analysis (PCA) have been done. A complex relationship between surface water and groundwater has been found. Sixty percent (60%) of groundwater samples are made of more than 70% river water and rainwater;while 31.25% of surface water samples are made of about 84% groundwater. To safeguard sustainable water resources for the well-being of the local communities, surface water and groundwater must be managed as a unique component in the Kandi basin.
文摘Interactions involving chemical reagents,solid particles,gas bubbles,liquid droplets,and solid surfaces in complex fluids play a vital role in many engineering processes,such as froth flotation,emulsion and foam formation,adsorption,and fouling and anti-fouling phenomena.These interactions at the molecular,nano-,and micro scale significantly influence and determine the macroscopic performance and efficiency of related engineering processes.Understanding the intermolecular and surface interactions in engineering processes is of both fundamental and practical importance,which not only improves production technologies,but also provides valuable insights into the development of new materials.In this review,the typical intermolecular and surface interactions involved in various engineering processes,including Derjaguin–Landau–Verwey–Overbeek(DLVO)interactions(i.e.,van der Waals and electrical doublelayer interactions)and non-DLVO interactions,such as steric and hydrophobic interactions,are first introduced.Nanomechanical techniques such as atomic force microscopy and surface forces apparatus for quantifying the interaction forces of molecules and surfaces in complex fluids are briefly introduced.Our recent progress on characterizing the intermolecular and surface interactions in several engineering systems are reviewed,including mineral flotation,petroleum engineering,wastewater treatment,and energy storage materials.The correlation of these fundamental interaction mechanisms with practical applications in resolving engineering challenges and the perspectives of the research field have also been discussed.
基金Project(2017YFC0805406)supported by the National Key Research and Development Program of ChinaProjects(51879142,51679123)supported by the National Natural Science Foundation of ChinaProject(2020-KY-04)supported by the Research Fund Program of the State Key Laboratory of Hydroscience and Engineering,China。
文摘Based on the interface shear tests,the macro-and meso-mechanical behaviors of interaction between coral sand and different structure surfaces are studied,in which CCD camera is used to capture digital images to analyze the evolution of the interaction band and a particle analysis apparatus is applied to studying the distribution characteristics of particle morphology.This study proposes four-stage evolution process based on the shear stress−strain curve.During the shear process,coral sand particles slide and rotate within the interaction band,causing the changes in shear stress and vertical displacement.In addition,the effects of structure surface roughness on shear strength,volume change and particle breakage are illustrated that the greater the roughness of slabs is,the larger the shear stress is,the more obvious the contraction effect is and the more the particles break.Furthermore,the change in particle’s 3D morphology during the breakage will change not only their size but also other morphological characteristics with convergence and self-organization.
基金This work was supported by the National Natural Science Foundation of China (51973157,61904123)the Tianjin Natural Science Foundation (18JCQNJC02900)+3 种基金the Special Grade of the Financial Support from the China Postdoctoral Science Foundation (2020T130469)the Sci-ence and Technology Plans of Tianjin (19PTSYJC00010)the Science&Technol-ogy Development Fund of Tianjin Education Commission for Higher Education (2018KJ196)State Key Laboratory of Membrane and Membrane Separation,Tiangong University.
文摘Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)transference number of these electrolytes significantly increase the internal resistance and overpotential of the battery.Here,we introduce Gd-doped CeO_(2) nanowires with large surface area and rich surface oxygen vacancies to the polymer electrolyte to increase the interaction between Gd-doped CeO_(2) nanowires and polymer electrolytes,which promotes the Li-salt dissociation and increases the concentration of mobile Li ions in the composite polymer electrolytes.The optimized composite polymer electrolyte has a high Li-ion conductivity of 5×10^(-4)4 S cm^(-1) at 30℃ and a large Li+transference number of 0.47.Moreover,the composite polymer electrolytes have excellent compatibility with the metallic lithium anode and high-voltage LiNi_(0.8)Mn _(0.1)Co_(0.1)O_(2)(NMC)cathode,providing the stable cycling of all-solid-state batteries at high current densities.
基金The Zeitenwende project, financed by the Helmholtz Association, is responsible for funding the work of some of the authors in this study。
文摘Grinding and flotation processes are often studied independently, despite the well-established grinding influence on flotation performance, which affects not only particle size and thus liberation but also shape and leads to complex changes in pulp chemistry affecting the particle surface properties relevant for selective bubble attachment. Yet, no study jointly investigated these possible causes and many are limited to single mineral flotation. We relate grinding conditions to changes in pulp chemistry and particle surface properties and assess their impact on upgrading. We studied three non-sulfide ores with different feed grades and valuables: scheelite, apatite, and fluorite. These were dry-, wet-, and wet conditionedground before flotation in a laboratory mechanical cell. Results were evaluated with bulk-and particle-specific methodologies. The selectivity of the process is higher after dry grinding for the fluorite and apatite ores and irrelevant for the scheelite ore. Variations in flotation kinetics of individual particles associated to their size and shape are not sufficient to explain these results. The higher concentration of Ca2+and Mg2+observed in the pulp after wet grinding, altering particle surface properties, better explains the phenomenon. Additionally, we demonstrate how particle shape impacts are system specific and related to both entrainment and true flotation.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10774162)
文摘We have studied the ionization of Rydberg hydrogen atom near a metal surface with a semiclassical analysis of photoionization microscopy. Interference patterns of the electron radial distribution are calculated at different scaled energies above the classical saddle point and at various atom surface distances. We find that different types of trajecto- ries contribute predominantly to different manifolds in a certain interference pattern. As the scaled energy increases, the structure of the interference pattern evolves smoothly and more types of trajectories emerge. As the atom approaches the metal surface closer, there are more types of trajectories contributing to the interference pattern as well. When the Rydberg atom comes very close to the metal surface or the scaled energy approaches the zero field ionization energy, the potential induced by the metal surface will make atomic system chaotic. The results also show that atoms near a metal surface exhibit similar properties like the atoms in the parallel electric and magnetic fields.
基金the Sino-Danish Centre for Education and Research, and the Technical University of Denmark for funding this project
文摘Fertilizer input for agricultural food production, as well as the discharge of domestic and industrial water pollutants, increases pressures on locally scarce and vulnerable water resources in the North China Plain. In order to：（a） understand pollutant exchange between surface water and groundwater,（b） quantify nutrient loadings, and（c） identify major nutrient removal pathways by using qualitative and quantitative methods, including the geochemical model PHREEQC） a one-year study at a wheat（Triticum aestivum L.） and maize（Zea mays L.） double cropping system in the Baiyang Lake area in Hebei Province, China, was undertaken. The study showed a high influence of low-quality surface water on the shallow aquifer. Major inflowing pollutants into the aquifer were ammonium and nitrate via inflow from the adjacent Fu River（up to 29.8 mg/L NH4-N and 6.8 mg/L NO3-N）, as well as nitrate via vertical transport from the field surface（up to 134.8 mg/L NO3-N in soil water）. Results from a conceptual model show an excess nitrogen input of about 320 kg/ha/a. Nevertheless,both nitrogen species were only detected at low concentrations in shallow groundwater,averaging at 3.6 mg/L NH4-N and 1.8 mg/L NO3-N. Measurement results supported by PHREEQC-modeling indicated cation exchange, denitrification, and anaerobic ammonium oxidation coupled with partial denitrification as major nitrogen removal pathways. Despite the current removal capacity, the excessive nitrogen fertilization may pose a future threat to groundwater quality. Surface water quality improvements are therefore recommended in conjunction with simultaneous monitoring of nitrate in the aquifer, and reduced agricultural N-inputs should be considered.
基金Supported by the National Natural Science Foundation of China under Grant No 51305033the Ministry of National Defense of China under Grant No 9140C340506
文摘An analytical simulation based on a new model incorporating surface interaction is conducted to study the slip phenomenon in the Couette flow at different scales. The velocity profile is calculated by taking account of the micro-force between molecules and macro-force from the viscous shearing effect, as they contribute to the achieve- ment of the slip length. The calculated results are compared with those obtained from the molecular dynamics simulation, showing an excellent agreement. Further, the effect of the shear rate on the slip is investigated. The results can well predict the fluid flow behaviors on a solid substrate, but has to be proved by experiment.
基金the auspices of National Natural Science Foundation of China(Nos.51827809,52077169)the National Key R&D Program of China(No.2020YFC2201100)。
文摘In this work,an improved understanding of electron sheath theory is provided using both fluid and kinetic approaches while elaborating on their implications for plasma–surface interactions.A fluid model is proposed considering the electron presheath structure,avoiding the singularity in electron sheath Child–Langmuir law which overestimates the sheath potential.Subsequently,a kinetic model of electron sheath is established,showing considerably different sheath proflles in respect to the fluid model due to non-Maxwellian electron velocity distribution function and flnite ion temperature.The kinetic model is then further generalized and involves a more realistic truncated ion velocity distribution function.It is demonstrated that such a distribution function yields a super-thermal electron sheath whose entering velocity at the sheath edge is greater than the Bohm criterion prediction.Furthermore,an attempt is made to describe the electron presheath–sheath coupling within the kinetic framework,showing a necessary compromise between a realistic sheath entrance and the inclusion of kinetic effects.Finally,the secondary electron emissions induced by sheath-accelerated plasma electrons in an electron sheath are analysed and the influence of backscattering is discussed.
基金the financial support of National Natural Science Foundation of China(Nos.51663005,21761007 and21871064)Science and Technology Plan Project of Guizhou Province(Nos.20175788 and 20185781)+2 种基金the Creative Research Groups of Guizhou Provincial Education Department(No.2017028)the Innovation Program for High-level Talents of Guizhou Province(No.20165657)“Chun-Hui” Fund of Chinese Ministry of Education(No.Z2017005)。
文摘Based on the crystal structures of two cucurbit[6]uril/calix[n]arene-based supramolecular frameworks reported by Long and co-workers,we further investigated the interactions of cucurbit[6]uril with 4-sulfocalix[4]arene and 4-sulfocalix[6]arene using ^(1)H NMR spectroscopy and isothermal titration calorimetry(ITC),respectively.Moreover,solid fluorescent materials were prepared via the adsorption of fluorescent dyes by these porous supramolecular frameworks,which exhibit a selective response to certain volatile organic compounds.
基金the financial support of the National Natural Science Foundation of China(Nos.21761007,51663005 and 21871064)Science and Technology Plan Project of Guizhou Province(Nos.20175788 and 20185781)。
文摘Curcurbit[n]uril(Q[n])-based supramolecular frameworks(QSFs) constructed from the outer surface interaction of Q[n]s(OSIQ) have the characteristic of simplicity,diversity and modulability.Their simplicity is reflected in their simple composition and preparation methods used for QSFs.The diversity of supramolecular organic frameworks(SOFs) is reflected in the synthesis methods and structural characteristics of the as-obtained QSFs,as well as the variety of structural directing agents and basic building blocks used to prepare QSFs.The modulability is reflected by the controllable channel size in the QSFs,which can be adjusted using different sizes of Q[n]s.In this work,the first re ported cucurbituril Q[6]was selected as the basic building block and three Q[6]-based su p ramolecular frameworks were obtained from aqueous HCl solutions in the presence of [CdCl_(4)]^(2-)respectively.The OSIQs are the main driving forces for the formation of these frameworks.This study shows the diversity of the QSFs.
基金The National Key R&D Program of China under contract No.2022YFE0209300the National Natural Science Foundation of China under contract No.42006152+1 种基金the Zhejiang Provincial Natural Science Foundation of China under contract No.LQ21D060005the 111 Project under contract No.BP0820020.
文摘Subterranean estuaries(STEs)are characterized by the mixing of terrestrial fresh groundwater and seawater in coastal aquifers.Although microorganisms are important components of coastal groundwater ecosystems and play critical roles in biogeochemical transformations in STEs,limited information is available about how their community dynamics interact with hydrological,geochemical and environmental characteristics in STEs.Here,we studied bacterial and archaeal diversities and distributions with 16S rRNA-based Illumina MiSeq sequencing technology between surface water and groundwater in a karstic STE.Principal-coordinate analysis found that the bacterial and archaeal communities in the areas where algal blooms occurred were significantly separated from those in other stations without algal bloom occurrence.Canonical correspondence analysis showed that nutrients and salinity can explain the patterns of bacterial and archaeal community dynamics.The results suggest that hydrological,geochemical and environmental characteristics between surface water and groundwater likely control the bacterial and archaeal diversities and distributions in STEs.Furthermore,we found that some key species can utilize terrestrial pollutants such as nitrate and ammonia in STEs,indicating that these species(e.g.,Nitrosopumilus maritimus,Limnohabitans parvus and Simplicispira limi)may be excellent candidates for in situ degradation/remediation of coastal groundwater contaminations concerned with the nitrate and ammonia.Overall,this study reveals the coupling relationship between the microbial communities and hydrochemical environments in STEs,and provides a perspective of in situ degradation/remediation for coastal groundwater quality management.
基金The projcct supportcd by National Natural Science Foundation of China
文摘The dynamics of the scattering processes of diatomic molecules from metal surfaces has been studied with different theoretical approaches. Modified LEPS (London-Eyring-Polanyi-Sato) potential surfaces for several diatomie molecule-surface systems have been constructed and examined for the dynamic study. The surfaces are treated as rigid but corrugated. The potential parameters are adjusted to produce reliable potential hypersurfaces. Molecular dissociation, diffraction, adsorption and consequent desorption in the scattering processes have been observed through quasiclassieal trajectory calculations. The significance of the effective corrugation of the potential surfaces has been evaluated in calculating the dissociation and adsorption probabilities. Vibration-rotation-translation energy transfer in the inelastic scattering is investigated to understand the mechanism of selective adsorptions mediated through vibrational or rotational degrees of freedom. We have carried out quantum mechanical calculations to obtain the rotational and vibrational transition probabilities. Relative importance of rotational and vibrational transitions for each adsorbed state with respect to incidence energy has been carefully examined to determine the dominant factor which causes the adsorbed state. The results show that vibration mediation is an essential factor to the selective adsorption especially in the ease of higher incidence energies.
基金financially supported by the National Natural Science Foundation of China(Nos.41702245,41807186)the National Natural Science Foundation of Hubei Province(No.2017CFC862)the Fundamental Research Funds for the Central Universities,South-Central Minzu University(No.CZQ21013)。
文摘Environment isotopes(δ18O andδ2H)and Cl/Br ratios in surface water and groundwater are combined to investigate arsenic mobilization in aquifer system of the Jianghan Plain.The groundwater has relatively high arsenic concentrations,ranging from 3.6 to 1055.3μg/L with an average of 102.2μg/L,which exceeds China’s drinking water standard(10μg/L).The arsenic content of surface water samples is quite low with the range of 6.0–14.3μg/L,averaging 9.5μg/L.δ18O andδ2H values for surface water and groundwater samples plot close to the local meteoric water line(LMWL),reflecting their meteoric origin;a subset of the samples(shallow wells,10 m)shows a shift to LMWL,commensurate with mixing with surface water and evaporation.The correlations betweenδ18O values and Cl concentration and Cl/Br ratios as well as arsenic concentration demonstrated that surface water and groundwater interactions,including active exchange between river/pond water and groundwater and vertical infiltration from agricultural and aquacultural soils,were dominated processes affecting arsenic mobilization in shallow groundwater system and lateral recharge was the main process controlling arsenic behavior in deep groundwater system.The results of this study will be beneficial to understanding the causes of arsenic mobilization in Jianghan groundwaters at different depths.
基金supported by the National Natural Science Foundation of China(No.51278409)the Education Department of Shaanxi Province(No.15JS046)
文摘Na-rich birnessite（NRB） was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion（NH＋4） from aqueous solution.In order to demonstrate the adsorption performance of the synthesized material,the effects of contact time,pH,initial ammonium ion concentration,and temperature were investigated.Adsorption kinetics showed that the adsorption behavior followed the pseudo second-order kinetic model.The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption models and the model parameters were evaluated.The monolayer adsorption capacity of the adsorbent,as obtained from the Langmuir isotherm,was 22.61 mg NH＋4-N/g at283 K.Thermodynamic analyses showed that the adsorption was spontaneous and that it was also a physisorption process.Our data revealed that the higher NH＋4adsorption capacity could be primarily attributed to the water absorption process and electrostatic interaction.Particularly,the high surface hydroxyl-content of NRB enables strong interactions with ammonium ion.The results obtained in this study illustrate that the NRB is expected to be an effective and economically viable adsorbent for ammonium ion removal from aqueous system.
文摘The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India.It also aims to define depth to granitoid and structural elements which traverse the selected area.Magnetic data(n=84)measured,processed and interpreted as qualitative and quantitatively.The results of total magnetic intensities indicate that the area is composed of linear magnetic lows trending NE-SW direction and circular to semi-circular causative bodies.The magnetic values ranged from-137 nT to 2345 nT with a mean of 465 nT.Reduction to equator shows significant shifting of causative bodies in the southern and northern directions.Analytical signal map shows exact boundary of granitic bodies.Cosine directional filter has brought out structural element trending NE-SW direction.Results of individual profile brought to light structurally weak zone between 90 m and 100 m in all the profile lines.Sudden decrease of magnetic values from 2042 nT to 126 nT noticed in profile line 6 between 20 m and 30 m indicates fault occurrence.Magnetic breaks obtained from these maps were visualized,interpreted and identified two suitable sites for open and bore well.Radially averaged power spectrum estimates depth of shallow and deep sources in 5 m and 50 m,respectively.Euler method has also been applied to estimate depth of granitoid and structural elements using structural indexes 0,1,2,and 3 and found depth ranges from<10 m to>90 m.Study indicates magnetic method is one of the geophysical methods suitable for groundwater exploration and site selection for open and borewells.
基金supported by a Garnett-Passe and Rodney Williams Memorial Foundation grant(to JE)a National Health and Medical Research Council grant,No.APP1183799(to JASJ and JAKE).
文摘The nerves of the peripheral nervous system are not able to effectively regenerate in cases of severe neural injury.This can result in debilitating consequences,including morbidity and lifelong impairments affecting the quality of the patient’s life.Recent findings in neural tissue engineering have opened promising avenues to apply fibrous tissue-engineered scaffolds to promote tissue regeneration and functional recovery.These scaffolds,known as neural scaffolds,are able to improve neural regeneration by playing two major roles,namely,by being a carrier for transplanted peripheral nervous system cells or biological cues and by providing structural support to direct growing nerve fibers towards the target area.However,successful implementation of scaffold-based therapeutic approaches calls for an appropriate design of the neural scaffold structure that is capable of up-and down-regulation of neuron-scaffold interactions in the extracellular matrix environment.This review discusses the main challenges that need to be addressed to develop and apply fibrous tissue-engineered scaffolds in clinical practice.It describes some promising solutions that,so far,have shown to promote neural cell adhesion and growth and a potential to repair peripheral nervous system injuries.
基金National Natural Science Foundation of China(Nos. 21871064, 21601090, 21761007, 51663005)Science and Technology Plan Project of Guizhou Province (Nos. 20175788 and20185781)+1 种基金Basic Research Program of Shenzhen (No. JCYJ20190812151405298)Shenzhen Peacock Plan。
文摘Since the outer surface interaction of Q[n]s (OSIQ, including self-, anion- and aromatic-induced OSIQs) was proposed in 2014, it has become the most important research area in our group to construct various Q[n]-based supramolecular frameworks via the OSIQ strategy. Herein, we report a novel supramolecular framework constructed using cucurbit[8]uril (Q[8]) and 4-sulfocalix[6]arene (SC[6]A). This Q[8]/SC[6]A-based supramolecular framework is a product via the perfect combination of self-, anion- and aromatic-induced OSIQs. This framework has the characteristics of easy preparation and high stability with the most important feature being the sequence selective capture of specific metal cations, such as common alkali- and alkaline earth metal ions, and renewability. Thus, this framework may be used in seawater desalination, potassium ion enrichment, radioactive cesium ion pollution source treatment, Gruinard's treatment or water softening and other applications.
基金supported by the National Natural Science Foundation of China(41271286)the Innovative Research Group Project of the National Natural Science Foundation of China(413221001)
文摘In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the erosion. However, the mutual influences between wind erosion and water erosion have not been fully understood. This research used a wind tunnel and two rainfall simulators and simulated two rounds of alternations between wind erosion and water erosion（i.e., 1^（st） wind erosion–1^（st） water erosion and 2^（nd） wind erosion–2^（nd） water erosion） on three slopes（5°, 10°, and 15°） with six wind speeds（0, 9, 11, 13, 15, and 20 m/s） and five rainfall intensities（0, 30, 45, 60, and 75 mm/h）. The objective was to analyze the influences of wind erosion on succeeding water erosion. Results showed that the effects of wind erosion on water erosion were not the same in the two rounds of tests. In the 1^（st） round of tests, wind erosion first restrained and then intensified water erosion mostly because the blocking effect of wind-sculpted micro-topography on surface flow was weakened with the increase in slope. In the 2^（nd） round of tests, wind erosion intensified water erosion on beds with no rills at gentle slopes and low rainfall intensities or with large-size rills at steep slopes and high rainfall intensities. Wind erosion restrained water erosion on beds with small rills at moderate slopes and moderate rainfall intensities. The effects were mainly related to the fine grain layer, rills and slope of the original bed in the 2^（nd） round of tests. The findings can deepen our understanding of complex erosion resulted from a combination of wind and water actions and provide scientific references to regional soil and water conservation.
基金supported by the Spanish Ministry of Economy and Competitiveness (Project CTQ2012-37925-C03-03)FEDER fundsby the Hungarian National Fund OTKA K109558
文摘Composites of carbon aerogel and graphite oxide（GO） were synthesized using a self-assembly method based on dispersive forces. Their surface was modified by treatment in hydrogen sulfide at 650 and800 ℃. The samples obtained were characterized by adsorption of nitrogen, TA-MS, XPS, potentiometric titration, and HRTEM and tested as catalysts for oxygen reduction reactions（ORR） in an alkaline medium.The synergistic effect of the composite（electrical conductivity, porosity and surface chemistry） leads to a good ORR catalytic activity. The onset potential for the composite of carbon aerogel heated at 800 ℃ is shifted to a more positive value and the number of electron transfer was 2e-at the potential 0.68 V versus RHE and it increased to 4e-with an increase in the negative values of the potential. An excellent tolerance to methanol crossover was also recorded.
