The importance of the study of saline/fresh water incursion cannot be over-emphasized. Borehole sampling has been extensively used, but it is intrusive, quite expensive and time consuming. Electrical resistivity and e...The importance of the study of saline/fresh water incursion cannot be over-emphasized. Borehole sampling has been extensively used, but it is intrusive, quite expensive and time consuming. Electrical resistivity and electromagnetic techniques have proved successful in groundwater studies since geologic formation properties like porosity and permeability can be correlated with electrical conductivity signatures. Non-intrusive surface geophysical mapping comprising electrical resistivity and electromagnetic methods has been employed to investigate freshwater intrusion and delineate the fresh-saline water interface at the inter-tidal area of Abergwygregyn, North Wales, United Kingdom. Frequency Domain Electromagnetic Profiling and Constant Separation Traversing were used to produce 2-D images and contour plots enabling the identification of freshwater plumes onshore and in the central parts of the study area. Ground truth methods comprised chemical analyses and detailed, point specific information on the stratigraphy. The freshwater intruding from the coastal area appears to be pushing the saline-water further offshore due to the high piezometric head caused by the mountains and hills of Snowdonia adjacent to the study area. The fresh/saline water interface correlates quite well with previous studies carried out in the area. On the basis of the results of the resistivity and conductivity geophysical investigations the freshwater plumes and fresh/saline water interface in the study area were effectively identified and delineated.展开更多
In situ growth of co-catalysts on BiVO_(4)(BVO)to enhance photoelectrochemical(PEC)water splitting performance has been extensively reported.However,the understanding of the synergistic effects among various elements,...In situ growth of co-catalysts on BiVO_(4)(BVO)to enhance photoelectrochemical(PEC)water splitting performance has been extensively reported.However,the understanding of the synergistic effects among various elements,especially at the interface between the semiconductor and cocatalyst,has received insufficient attention.In this study,we report a Co,Ni and Mn trimetallic fluoride-modified BVO photoanode featuring a unique interfacial chemical bond(V-F).Under AM 1.5 G illumination,an exciting photocurrent density of 6.05 mA cm^(-2)was achieved at 1.23 V vs.RHE by the integrated BVO/CoNi_(0.18)Mn_(0.12)(OH)_(x)F photoanode and over 98%of the initial photocurrent was maintained after 10 h of photoelectrolysis.Control experiments and theoretical calculations demonstrate that the V-F interfacial bond stabilizes the Co^(2+)active sites.It serves as a transmission gear,interlinking the migration of interfacial charge and the regeneration of cocatalyst,endowing the photoanode with significant activity and stability.Furthermore,we have systematically elucidated the role of the individual Co,Ni,and Mn components in the synergistic cocatalyst layer.The interfacial modification provides novel insights into developing advanced photoanodes towards PEC water splitting.展开更多
The design of efficient and cost‐effective bifunctional catalysts, which are capable of driving both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of paramount importance for advancing...The design of efficient and cost‐effective bifunctional catalysts, which are capable of driving both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of paramount importance for advancing overall water splitting. Here, we developed an innovative heterogeneous interface engineering strategy to boost the electrocatalytic performance of overall water splitting. This approach involves the synergistic integration of ultra‐fine CoMoP nanocrystals coupled with three‐ dimensional (3D) porous C3N4/N‐doped carbon (NC) architectures, constructing a distinctive CoMoP/C3N4/NC heterogeneous interface. The CoMoP/C3N4/NC exhibits distinguished overall water splitting performance. To drive the overall water splitting current of 10 mA cm−2, the CoMoP/C3N4/NC||CoMoP/C3N4/NC electrolysis cell only needs an ultralow cell voltage of 1.496 V. The electronic properties and localized coordination environments characterizations, and density functional theory (DFT) calculations elucidate that the improved catalytic activities of CoMoP/C3N4/NC are primarily attributed to the synergistic interfacial coupling between CoMoP/C3N4/NC heterogeneous interface. A novel multi‐site synergistic catalytic mechanism was revealed by the DFT calculations, in which the optimum H* adsorption site on CoMoP/C3N4/NC for HER is on the cobalt atoms in CoMoP with the ultralow Gibbs free energy of hydrogen bonding (ΔGH*) of 0.018 eV, while for the OER, the optimum intermediates adsorption site of the CoMoP/C3N4/NC is on the carbon atoms in C3N4/NC. Besides, the intricately engineered 3D hierarchical porous framework of the CoMoP/C3N4/NC can facilitate the ion and electron transport and improve mass transfer, which gives rise to enhanced water splitting performance.展开更多
Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductanc...Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductance to survey soil water profiles and comparing it with root distribution surveyed by soil coring and root harvesting in Changbai Mountain in 1999. The results were: (1) The profiles of soil water content were adjusted by root activity. The water content of the soil layer with abundant roots was higher. (2) When CO 2 concentration was doubled, water transport was more active at the root/soil interface and the roots were distributed into deeper layer. It was shown in this work that the method of measuring electric conductance is an inexpensive, non_destructive and relatively sensitive way for underground water transport process.展开更多
The Marano and Grado Lagoon is well known for being contaminated by mercury（Hg） from the Idrija mine（Slovenia） and the decommissioned chlor-alkali plant of Torviscosa（Italy）.Experimental activities were conducte...The Marano and Grado Lagoon is well known for being contaminated by mercury（Hg） from the Idrija mine（Slovenia） and the decommissioned chlor-alkali plant of Torviscosa（Italy）.Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments（up to 6.81 μg/g）showed a slight variability with depth, whereas the highest methylmercury（MeHg） values（up to 10 ng/g） were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally（from 0.1 and 17% of dissolved Hg（DHg）） with the highest concentrations in summer. DHg diffusive effluxes higher（up to 444 ng/m^2/day） than those reported in the open lagoon（~ 95 ng/m^2/day）, whereas DMeHg showed influxes in the fish farm（up to-156 ng/m^2/day）. The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.展开更多
Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitu...Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitudes of the benthic exchange fluxes were determined on the basis of concentration gradients of ammonium and nitrate at the near-bottom water and interstitial water interface in combination with calculations of a modified Fick＇ s first law. Ammonium fluxes varied from - 5.05 to 1.43 μg/（ cm^2·d） and were greatly regulated by the production of ammonium in surface sediments, while nitrate fluxes ranged from - 0. 38 to 1.36 μg/ （ cm^2·d） and were dominated by nitrate concentrations in the tidal water. It was found that ammonium was mainly released from sediments into water columns at most of stations whereas nitrate was mostly diffused from overlying waters to intertidal sediments. In total, 823.75 t/a ammonium-N was passed from intertidal sediments to water while about 521.90 t/a nitrate-N was removed from overlying waters to intertidal sediments. This suggests that intertidal sediments had the significant influence on modulating inorganic nitrogen in the tidal water.展开更多
Highly active and durable bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) play a pivotal role in overall water splitting. Herein, we demonstrate the construction...Highly active and durable bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) play a pivotal role in overall water splitting. Herein, we demonstrate the construction of interface-strengthened CoP nanosheet array with Co2P nanoparticles as such an electrocatalyst through a facile hydrothermal reaction and the subsequent phosphorization process. The twodimensional (2D) nanosheets with thickness of^55 nm expose a great number of active sites. The surface chemical state indicates that the strongly coupled CoP/Co2P electrocatalysts can adsorb or generate more targeted intermediates (e.g. OH- or OOH*) for both HER/OER. As a result, the CoP/Co2P electrocatalysts exhibit small overpotentials of 68 and 256 mV to drive 10 mA cm^-2 for HER and OER, respectively, outperforming most of the recently reported Co-based electrocatalysts. Furthermore, an alkaline electrolyzer assembled by using CoP/Co2P as both cathode and anode can achieve a current density of 10 mA cm^-2 at a low voltage of 1.57 V and work continuously for over 58 h. This work provides a feasible structural design for transition metal phosphides electrocatalysts with efficient and stable overall water splitting.展开更多
The sluggish kinetics of both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)generate the large overpotential in water electrolysis and thus high-cost hydrogen production.Here,multidimensional nanop...The sluggish kinetics of both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)generate the large overpotential in water electrolysis and thus high-cost hydrogen production.Here,multidimensional nanoporous interpenetrating-phase FeNiZn alloy and FeNi_(3)intermetallic heterostructure is in situ constructed on NiFe foam(FeNiZn/FeNi_(3)@NiFe)by dealloying protocol.Coupling with the eminent synergism among specific constituents and the highly efficient mass transport from integrated porous backbone,FeNiZn/FeNi_(3)@NiFe depicts exceptional bifunctional activities for water splitting with extremely low overpotentials toward OER and HER(η_(1000)=367/245 mV)as well as the robust durability during the 400 h testing in alkaline solution.The as-built water electrolyzer with FeNiZn/FeNi_(3)@NiFe as both anode and cathode exhibits record-high performances for sustainable hydrogen output in terms of much lower cell voltage of 1.759 and 1.919 V to deliver the current density of 500 and 1000 mA cm^(-2)as well long working lives.Density functional theory calculations disclose that the interface interaction between FeNiZn alloy and FeNi_(3)intermetallic generates the modulated electron structure state and optimized intermediate chemisorption,thus diminishing the energy barriers for hydrogen production in water splitting.With the merits of fine performances,scalable fabrication,and low cost,FeNiZn/FeNi_(3)@NiFe holds prospective application potential as the bifunctional electrocatalyst for water splitting.展开更多
Direct photon to chemical energy conversion using semiconductor–electrocatalyst–electrolyte interfaces has been extensively investigated for more than a half century. Many studies have focused on screening materials...Direct photon to chemical energy conversion using semiconductor–electrocatalyst–electrolyte interfaces has been extensively investigated for more than a half century. Many studies have focused on screening materials for efficient photocatalysis. Photocatalytic efficiency has been improved during this period but is not sufficient for industrial commercialization. Detailed elucidation on the photocatalytic water splitting process leads to consecutive six reaction steps with the fundamental parameters involved: The photocatalysis is initiated involving photophysics derived from various semiconductor properties(1: photon absorption, 2: exciton separation). The generated charge carriers need to be transferred to surfaces effectively utilizing the interfaces(3: carrier diffusion, 4: carrier transport). Consequently, electrocatalysis finishes the process by producing products on the surface(5: catalytic efficiency, 6: mass transfer of reactants and products). Successful photocatalytic water splitting requires the enhancement of efficiency at each stage. Most critically, a fundamental understanding of the interfacial phenomena is highly desired for establishing 'photocatalysis by design' concepts, where the kinetic bottleneck within a process is identified by further improving the specific properties of photocatalytic materials as opposed to blind material screening. Theoretical modeling using the identified quantitative parameters can effectively predict the theoretically attainable photon-conversion yields. This article provides an overview of the state-of-the-art theoretical understanding of interfacial problems mainly developed in our laboratory.Photocatalytic water splitting(especially hydrogen evolution on metal surfaces) was selected as a topic,and the photophysical and electrochemical processes that occur at semiconductor–metal, semiconductor–electrolyte and metal–electrolyte interfaces are discussed.展开更多
Exploring highly active and stable transition metal-based bifunctional electrocatalysts has recently attracted extensive research interests for achieving high inherent activity, abundant exposed active sites, rapid ma...Exploring highly active and stable transition metal-based bifunctional electrocatalysts has recently attracted extensive research interests for achieving high inherent activity, abundant exposed active sites, rapid mass transfer, and strong structure stability for overall water splitting. Herein, an interface engineering coupled with shell-protection strategy was applied to construct three-dimensional(3D) core-shell NixSy@MnOxHy heterostructure nanorods grown on nickel foam(NixSy@MnOxHy/NF) as a bifunctional electrocatalyst. NixSy@MnOxHy/NF was synthesized via a facile hydrothermal reaction followed by an electrodeposition process. The X-ray absorption fine structure spectra reveal that abundant Mn-S bonds connect the heterostructure interfaces of N ixSy@MnOxHy, leading to a strong electronic interaction, which improves the intrinsic activities of hydrogen evolution reaction and oxygen evolution reaction(OER). Besides, as an efficient protective shell, the MnOxHy dramatically inhibits the electrochemical corrosion of the electrocatalyst at high current densities, which remarkably enhances the stability at high potentials. Furthermore, the 3D nanorod structure not only exposes enriched active sites, but also accelerates the electrolyte diffusion and bubble desorption. Therefore, NixSy@MnOxHy/NF exhibits exceptional bifunctional activity and stability for overall water splitting, with low overpotentials of 326 and 356 mV for OER at 100 and 500 mA cm^(–2), respectively, along with high stability of 150 h at 100 mA cm^(–2). Furthermore, for overall water splitting, it presents a low cell voltage of 1.529 V at 10 mA cm^(–2), accompanied by excellent stability at 100 mA cm^(–2) for 100 h. This work sheds a light on exploring highly active and stable bifunctional electrocatalysts by the interface engineering coupled with shell-protection strategy.展开更多
Efficient utilization of electrostatic charges is paramount for numerous applications,from printing to kinetic energy harvesting.However,existing technologies predominantly focus on the static qualities of these charg...Efficient utilization of electrostatic charges is paramount for numerous applications,from printing to kinetic energy harvesting.However,existing technologies predominantly focus on the static qualities of these charges,neglecting their dynamic capabilities as carriers for energy conversion.Herein,we report a paradigm-shifting strategy that orchestrates the swift transit of surface charges,generated through contact electrification,via a freely moving droplet.This technique ingeniously creates a bespoke charged surface which,in tandem with a droplet acting as a transfer medium to the ground,facilitates targeted charge displacement and amplifies electrical energy collection.The spontaneously generated electric field between the charged surface and needle tip,along with the enhanced water ionization under the electric field,proves pivotal in facilitating controlled charge transfer.By coupling the effects of charge self-transfer,contact electrification,and electrostatic induction,a dual-electrode droplet-driven(DD)triboelectric nanogenerator(TENG)is designed to harvest the water-related energy,exhibiting a two-orderof-magnitude improvement in electrical output compared to traditional single-electrode systems.Our strategy establishes a fundamental groundwork for efficient water drop energy acquisition,offering deep insights and substantial utility for future interdisciplinary research and applications in energy science.展开更多
Producing highly efficient bifunctional catalyst for the generation of hydrogen and oxygen through overall water splitting is an emerging direction in electrocatalysis.Herein,a dandelion-like hierarchical NiMoP_(2)-Ni...Producing highly efficient bifunctional catalyst for the generation of hydrogen and oxygen through overall water splitting is an emerging direction in electrocatalysis.Herein,a dandelion-like hierarchical NiMoP_(2)-Ni_(2)P(nanowire/nanoparticle)heterostructure was synthesized for efficient electrochemical water splitting.The NiMoP_(2)-Ni_(2)P heterostructures grown on carbon cloth as a freestanding integrated electrode exhibited excellent oxygen evolution reaction(OER)activity and hydrogen evolution reaction(HER)activities with low overpotentials(258 mV and 53 mV to reach 10 mA cm~(-2)for the OER and HER,respectively),and small Tafel slope(45 mV dec^(-1)and 58 mV dec^(-1)for the OER and HER,respectively).Moreover,the NiMoP_(2)-Ni_(2)P heterostructure can act as both anode and cathode catalysts for overall water splitting with low overall potential of 1.48 V at 10 mA cm~(-2).Density functional theory(DFT)combined with structural probes suggests that the amorphous heterogeneous interfaces play an essential role in enhanced catalytic performance.展开更多
Nowdays,electrocatalytic water splitting has been regarded as one of the most efficient means to approach the urgent energy crisis and environmental issues.However,to speed up the electrocatalytic conversion efficienc...Nowdays,electrocatalytic water splitting has been regarded as one of the most efficient means to approach the urgent energy crisis and environmental issues.However,to speed up the electrocatalytic conversion efficiency of their half reactions including hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),electrocatalysts are usually essential to reduce their kinetic energy barriers.Electrospun nanomaterials possess a unique one‐dimensional structure for outstanding electron and mass transportation,large specific surface area,and the possibilities of flexibility with the porous feature,which are good candidates as efficient electrocatalysts for water splitting.In this review,we focus on the recent research progress on the electrospun nanomaterials‐based electrocatalysts for HER,OER,and overall water splitting reaction.Specifically,the insights of the influence of the electronic modulation and interface engineering of these electrocatalysts on their electrocatalytic activities will be deeply discussed and highlighted.Furthermore,the challenges and development opportunities of the electrospun nanomaterials‐based electrocatalysts for water splitting are featured.Based on the achievements of the significantly enhanced performance from the electronic modulation and interface engineering of these electrocatalysts,full utilization of these materials for practical energy conversion is anticipated.展开更多
Designing cost-effective and high-efficiency electrocatalysts is critical to the water splitting performance during hydrogen generation.Herein,we have developed Fe_(2)P-Co_(2)P heterostructure nanowire arrays with exc...Designing cost-effective and high-efficiency electrocatalysts is critical to the water splitting performance during hydrogen generation.Herein,we have developed Fe_(2)P-Co_(2)P heterostructure nanowire arrays with excellent lattice torsions and grain boundaries for highly efficient water splitting.According to the microstructural investigations and theoretical calculations,the lattice torsion interface not only contributes to the exposure of more active sites but also effectively tunes the adsorption energy of hydrogen/oxygen intermediates via the accumulation of charge redistribution.As a result,the Fe_(2)P-Co_(2)P heterostructure nanowire array exhibits exceptional bifunctional catalytic activity with overpotentials of 65 and 198 mV at 10 mA cm^(-2) for hydrogen and oxygen evolution reactions,respectively.Moreover,the Fe_(2)P-Co_(2)P/NF-assembled electrolyzer can deliver 10 mA cm^(-2) at an ultralow voltage of1.51 V while resulting in a high solar-to-hydrogen conversion efficiency of 19.8%in the solar-driven water electrolysis cell.展开更多
Electrochemical （EC） reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique...Electrochemical （EC） reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique for chemical analysis, yet its application to EC reactions is hindered by the strong attenuation of infrared （IR） light in both electrodes and electrolytes. Here we demonstrate that by incorporating appropriate sub-wavelength plasmonic structures at the metal electrode, the IR field at the EC interface can be greatly enhanced via the excitation of surface plasmon. This scheme facilitates in situ vibrational spectroscopic studies, especially using the surface-specific sum-frequency generation technique.展开更多
We have previously developed a new process of highly efficient conversion of COand water into formic acid with metallic Zn without the addition of catalyst, however, its mechanism is not clear, particularly in the cat...We have previously developed a new process of highly efficient conversion of COand water into formic acid with metallic Zn without the addition of catalyst, however, its mechanism is not clear, particularly in the catalytic role of Zn/ZnO interface. Herein, the autocatalytic role of Zn/ZnO interface formed in situ during the reduction of COinto formic acid with Zn in water was studied by combining high resolution transmission electron microscopy（HRTEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS） techniques and experimental data. The electron microscope results show that possible defects or dislocations formed on Zn/ZnO interface, in which plays a key role for Zn H-formation. Further XPS analyses indicate that oxygen vacancies on Zn/ZnO interface increased at short reaction times（less than 10 min）. These analyses and experimental results suggest that a highly efficient and rapid conversion of COand water into formic acid should involve an autocatalytic role of the Zn/ZnO interface formed in situ, particularly at the beginning of the reaction.展开更多
The electronic structures and properties of electrocatalysts,which depend on the physicochemical structure and metallic element components,could significantly affect their electrocatalytic performance and their future...The electronic structures and properties of electrocatalysts,which depend on the physicochemical structure and metallic element components,could significantly affect their electrocatalytic performance and their future applications in Zn-air battery(ZAB)and overall water splitting(OWS).Here,by combining vacancies and heterogeneous interfacial engineering,three-dimensional(3D)core-shell NiCoP/NiO heterostructures with dominated oxygen vacancies have been controllably in-situ grown on carbon cloth for using as highly efficient electrocatalysts toward hydrogen and oxygen electrochemical reactions.Theoretical calculation and electrochemical results manifest that the hybridization of NiCoP core with NiO shell produces a strong synergistic electronic coupling effect.The oxygen vacancy can enable the emergence of new electronic states within the band gap,crossing the Fermi levels of the two spin components and optimizing the local electronic structure.Besides,the hierarchical core-shell NiCoP/NiO nanoarrays also endow the catalysts with multiple exposed active sites,faster mass transfer behavior,optimized electronic strutures and improved electrochemical performance during ZAB and OWS applications.展开更多
Here we report a quantitative study of the orientational structure and motion of water molecule at the air/water interface. Analysis of Sum Frequency Generation （SFG） vibrational peak of the free O-H stretching band...Here we report a quantitative study of the orientational structure and motion of water molecule at the air/water interface. Analysis of Sum Frequency Generation （SFG） vibrational peak of the free O-H stretching band at 3700 cm^-1 in four experimental configurations showed that orientational motion of water molecule at air/water interface is libratory within a limited angular range. The free OH bond of the interracial water molecule is tilted around 33°from the interface normal and the orientational distribution or motion width is less than 15°. This picture is significantly different from the previous conclusion that the interracial water molecule orientation varies over a broad range within the ultrafast vibrational relaxation time, the only direct experimental study concluded for ultrafast and broad orient, ational motion of a liquid interface by Wei et al. （Phys. Rev. Lett. 86, 4799, （2001）） using single SFG experimental configuration.展开更多
Studies on nonlinear behavior at oil/water interface membrane were performed. This system showed rhythmic oscillations and chaos of electrical potential in a given concentration domain. The nonlinear behavior response...Studies on nonlinear behavior at oil/water interface membrane were performed. This system showed rhythmic oscillations and chaos of electrical potential in a given concentration domain. The nonlinear behavior response at the liquid membrane apparently resembled that of biological chemoreceptive membrane. The possibility of developing a new type of chemical sensor with the ability to simulate substance equilibrium in living organisms was suggested in the paper.展开更多
High-speed planing crafts have successfully evolved through developments in the last several decades.Classical approaches such as inviscid potential flow–based methods and the empirically based Savitsky method provid...High-speed planing crafts have successfully evolved through developments in the last several decades.Classical approaches such as inviscid potential flow–based methods and the empirically based Savitsky method provide general understanding for practical design.However,sometimes such analyses suffer inaccuracies since the air–water interface effects,especially in the transition phase,are not fully accounted for.Hence,understanding the behaviour at the transition speed is of fundamental importance for the designer.The fluid forces in planing hulls are dominated by phenomena such as flow separation at various discontinuities viz.,knuckles,chines and transom,with resultant spray generation.In such cases,the application of potential theory at high speeds introduces limitations.This paper investigates the simulation of modelling of the pre-planing behaviour with a view to capturing the air–water interface effects,with validations through experiments to compare the drag,dynamic trim and wetted surface area.The paper also brings out the merits of gridding strategies to obtain reliable results especially with regard to spray generation due to the air–water interface effects.The verification and validation studies serve to authenticate the use of the multi-gridding strategies on the basis of comparisons with simulations using model tests.It emerges from the study that overset/chimera grids give better results compared with single unstructured hexahedral grids.Two overset methods are investigated to obtain reliable estimation of the dynamic trim and drag,and their ability to capture the spray resulting from the air–water interaction.The results demonstrate very close simulation of the actual flow kinematics at steady-speed conditions in terms of spray at the air–water interface,drag at the pre-planing and full planing range and dynamic trim angles.展开更多
文摘The importance of the study of saline/fresh water incursion cannot be over-emphasized. Borehole sampling has been extensively used, but it is intrusive, quite expensive and time consuming. Electrical resistivity and electromagnetic techniques have proved successful in groundwater studies since geologic formation properties like porosity and permeability can be correlated with electrical conductivity signatures. Non-intrusive surface geophysical mapping comprising electrical resistivity and electromagnetic methods has been employed to investigate freshwater intrusion and delineate the fresh-saline water interface at the inter-tidal area of Abergwygregyn, North Wales, United Kingdom. Frequency Domain Electromagnetic Profiling and Constant Separation Traversing were used to produce 2-D images and contour plots enabling the identification of freshwater plumes onshore and in the central parts of the study area. Ground truth methods comprised chemical analyses and detailed, point specific information on the stratigraphy. The freshwater intruding from the coastal area appears to be pushing the saline-water further offshore due to the high piezometric head caused by the mountains and hills of Snowdonia adjacent to the study area. The fresh/saline water interface correlates quite well with previous studies carried out in the area. On the basis of the results of the resistivity and conductivity geophysical investigations the freshwater plumes and fresh/saline water interface in the study area were effectively identified and delineated.
文摘In situ growth of co-catalysts on BiVO_(4)(BVO)to enhance photoelectrochemical(PEC)water splitting performance has been extensively reported.However,the understanding of the synergistic effects among various elements,especially at the interface between the semiconductor and cocatalyst,has received insufficient attention.In this study,we report a Co,Ni and Mn trimetallic fluoride-modified BVO photoanode featuring a unique interfacial chemical bond(V-F).Under AM 1.5 G illumination,an exciting photocurrent density of 6.05 mA cm^(-2)was achieved at 1.23 V vs.RHE by the integrated BVO/CoNi_(0.18)Mn_(0.12)(OH)_(x)F photoanode and over 98%of the initial photocurrent was maintained after 10 h of photoelectrolysis.Control experiments and theoretical calculations demonstrate that the V-F interfacial bond stabilizes the Co^(2+)active sites.It serves as a transmission gear,interlinking the migration of interfacial charge and the regeneration of cocatalyst,endowing the photoanode with significant activity and stability.Furthermore,we have systematically elucidated the role of the individual Co,Ni,and Mn components in the synergistic cocatalyst layer.The interfacial modification provides novel insights into developing advanced photoanodes towards PEC water splitting.
基金supported by the National Natural Science Foundation of China(Grant No.12375303)the Natural Science Foundation of Guangdong Province(Grants No.2024A1515030034 and 2023A1515140156).
文摘The design of efficient and cost‐effective bifunctional catalysts, which are capable of driving both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of paramount importance for advancing overall water splitting. Here, we developed an innovative heterogeneous interface engineering strategy to boost the electrocatalytic performance of overall water splitting. This approach involves the synergistic integration of ultra‐fine CoMoP nanocrystals coupled with three‐ dimensional (3D) porous C3N4/N‐doped carbon (NC) architectures, constructing a distinctive CoMoP/C3N4/NC heterogeneous interface. The CoMoP/C3N4/NC exhibits distinguished overall water splitting performance. To drive the overall water splitting current of 10 mA cm−2, the CoMoP/C3N4/NC||CoMoP/C3N4/NC electrolysis cell only needs an ultralow cell voltage of 1.496 V. The electronic properties and localized coordination environments characterizations, and density functional theory (DFT) calculations elucidate that the improved catalytic activities of CoMoP/C3N4/NC are primarily attributed to the synergistic interfacial coupling between CoMoP/C3N4/NC heterogeneous interface. A novel multi‐site synergistic catalytic mechanism was revealed by the DFT calculations, in which the optimum H* adsorption site on CoMoP/C3N4/NC for HER is on the cobalt atoms in CoMoP with the ultralow Gibbs free energy of hydrogen bonding (ΔGH*) of 0.018 eV, while for the OER, the optimum intermediates adsorption site of the CoMoP/C3N4/NC is on the carbon atoms in C3N4/NC. Besides, the intricately engineered 3D hierarchical porous framework of the CoMoP/C3N4/NC can facilitate the ion and electron transport and improve mass transfer, which gives rise to enhanced water splitting performance.
文摘Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductance to survey soil water profiles and comparing it with root distribution surveyed by soil coring and root harvesting in Changbai Mountain in 1999. The results were: (1) The profiles of soil water content were adjusted by root activity. The water content of the soil layer with abundant roots was higher. (2) When CO 2 concentration was doubled, water transport was more active at the root/soil interface and the roots were distributed into deeper layer. It was shown in this work that the method of measuring electric conductance is an inexpensive, non_destructive and relatively sensitive way for underground water transport process.
基金supported by the University of Trieste (Finanziamento di Ateneo per progetti di ricerca scientifica-FRA 2014,ref.Stefano Covelli)
文摘The Marano and Grado Lagoon is well known for being contaminated by mercury（Hg） from the Idrija mine（Slovenia） and the decommissioned chlor-alkali plant of Torviscosa（Italy）.Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments（up to 6.81 μg/g）showed a slight variability with depth, whereas the highest methylmercury（MeHg） values（up to 10 ng/g） were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally（from 0.1 and 17% of dissolved Hg（DHg）） with the highest concentrations in summer. DHg diffusive effluxes higher（up to 444 ng/m^2/day） than those reported in the open lagoon（~ 95 ng/m^2/day）, whereas DMeHg showed influxes in the fish farm（up to-156 ng/m^2/day）. The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.
基金This research is part of the project of the biogeochemical cycling of multi-materials in the Changjiang estuarine and coastal complex ecosystem supported by the National Natural Science Key Foundation of China under contract Nos 40131020 and 49801018 the Tidal Flat Project by Science and Technology Committee of Shanghai under contract No. 04DZ12049+1 种基金 China Postdoctoral Science Foundation under contract No. 2005037135 Shanghai Postdoctoral Science Foundation under contract No.04R214122.
文摘Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitudes of the benthic exchange fluxes were determined on the basis of concentration gradients of ammonium and nitrate at the near-bottom water and interstitial water interface in combination with calculations of a modified Fick＇ s first law. Ammonium fluxes varied from - 5.05 to 1.43 μg/（ cm^2·d） and were greatly regulated by the production of ammonium in surface sediments, while nitrate fluxes ranged from - 0. 38 to 1.36 μg/ （ cm^2·d） and were dominated by nitrate concentrations in the tidal water. It was found that ammonium was mainly released from sediments into water columns at most of stations whereas nitrate was mostly diffused from overlying waters to intertidal sediments. In total, 823.75 t/a ammonium-N was passed from intertidal sediments to water while about 521.90 t/a nitrate-N was removed from overlying waters to intertidal sediments. This suggests that intertidal sediments had the significant influence on modulating inorganic nitrogen in the tidal water.
基金supported by the National Natural Science Foundation of China (21838003, 91534122)the Social Development Program of Shanghai (17DZ1200900)+2 种基金the Shanghai Scientific and Technological Innovation Project (18JC1410600)the Program for Shanghai Youth Top-notch Talentthe Fundamental Research Funds for the Central Universities (222201718002)
文摘Highly active and durable bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) play a pivotal role in overall water splitting. Herein, we demonstrate the construction of interface-strengthened CoP nanosheet array with Co2P nanoparticles as such an electrocatalyst through a facile hydrothermal reaction and the subsequent phosphorization process. The twodimensional (2D) nanosheets with thickness of^55 nm expose a great number of active sites. The surface chemical state indicates that the strongly coupled CoP/Co2P electrocatalysts can adsorb or generate more targeted intermediates (e.g. OH- or OOH*) for both HER/OER. As a result, the CoP/Co2P electrocatalysts exhibit small overpotentials of 68 and 256 mV to drive 10 mA cm^-2 for HER and OER, respectively, outperforming most of the recently reported Co-based electrocatalysts. Furthermore, an alkaline electrolyzer assembled by using CoP/Co2P as both cathode and anode can achieve a current density of 10 mA cm^-2 at a low voltage of 1.57 V and work continuously for over 58 h. This work provides a feasible structural design for transition metal phosphides electrocatalysts with efficient and stable overall water splitting.
基金supported by National Science Foundation of China(52201254)Shandong Province(ZR2020MB090,ZR2020QE012)the project of“20 Items of University”of Jinan(202228046)。
文摘The sluggish kinetics of both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)generate the large overpotential in water electrolysis and thus high-cost hydrogen production.Here,multidimensional nanoporous interpenetrating-phase FeNiZn alloy and FeNi_(3)intermetallic heterostructure is in situ constructed on NiFe foam(FeNiZn/FeNi_(3)@NiFe)by dealloying protocol.Coupling with the eminent synergism among specific constituents and the highly efficient mass transport from integrated porous backbone,FeNiZn/FeNi_(3)@NiFe depicts exceptional bifunctional activities for water splitting with extremely low overpotentials toward OER and HER(η_(1000)=367/245 mV)as well as the robust durability during the 400 h testing in alkaline solution.The as-built water electrolyzer with FeNiZn/FeNi_(3)@NiFe as both anode and cathode exhibits record-high performances for sustainable hydrogen output in terms of much lower cell voltage of 1.759 and 1.919 V to deliver the current density of 500 and 1000 mA cm^(-2)as well long working lives.Density functional theory calculations disclose that the interface interaction between FeNiZn alloy and FeNi_(3)intermetallic generates the modulated electron structure state and optimized intermediate chemisorption,thus diminishing the energy barriers for hydrogen production in water splitting.With the merits of fine performances,scalable fabrication,and low cost,FeNiZn/FeNi_(3)@NiFe holds prospective application potential as the bifunctional electrocatalyst for water splitting.
基金supported by funding from King Abdullah University of Science and Technology(KAUST)
文摘Direct photon to chemical energy conversion using semiconductor–electrocatalyst–electrolyte interfaces has been extensively investigated for more than a half century. Many studies have focused on screening materials for efficient photocatalysis. Photocatalytic efficiency has been improved during this period but is not sufficient for industrial commercialization. Detailed elucidation on the photocatalytic water splitting process leads to consecutive six reaction steps with the fundamental parameters involved: The photocatalysis is initiated involving photophysics derived from various semiconductor properties(1: photon absorption, 2: exciton separation). The generated charge carriers need to be transferred to surfaces effectively utilizing the interfaces(3: carrier diffusion, 4: carrier transport). Consequently, electrocatalysis finishes the process by producing products on the surface(5: catalytic efficiency, 6: mass transfer of reactants and products). Successful photocatalytic water splitting requires the enhancement of efficiency at each stage. Most critically, a fundamental understanding of the interfacial phenomena is highly desired for establishing 'photocatalysis by design' concepts, where the kinetic bottleneck within a process is identified by further improving the specific properties of photocatalytic materials as opposed to blind material screening. Theoretical modeling using the identified quantitative parameters can effectively predict the theoretically attainable photon-conversion yields. This article provides an overview of the state-of-the-art theoretical understanding of interfacial problems mainly developed in our laboratory.Photocatalytic water splitting(especially hydrogen evolution on metal surfaces) was selected as a topic,and the photophysical and electrochemical processes that occur at semiconductor–metal, semiconductor–electrolyte and metal–electrolyte interfaces are discussed.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(2021A1515110859)the Research Fund Program of Key Laboratory of Fuel Cell Technology of Guangdong Province+2 种基金the Natural Sciences and Engineering Research Council of Canada(NSERC)Institut National de la Recherche Scientifique(INRS)。
文摘Exploring highly active and stable transition metal-based bifunctional electrocatalysts has recently attracted extensive research interests for achieving high inherent activity, abundant exposed active sites, rapid mass transfer, and strong structure stability for overall water splitting. Herein, an interface engineering coupled with shell-protection strategy was applied to construct three-dimensional(3D) core-shell NixSy@MnOxHy heterostructure nanorods grown on nickel foam(NixSy@MnOxHy/NF) as a bifunctional electrocatalyst. NixSy@MnOxHy/NF was synthesized via a facile hydrothermal reaction followed by an electrodeposition process. The X-ray absorption fine structure spectra reveal that abundant Mn-S bonds connect the heterostructure interfaces of N ixSy@MnOxHy, leading to a strong electronic interaction, which improves the intrinsic activities of hydrogen evolution reaction and oxygen evolution reaction(OER). Besides, as an efficient protective shell, the MnOxHy dramatically inhibits the electrochemical corrosion of the electrocatalyst at high current densities, which remarkably enhances the stability at high potentials. Furthermore, the 3D nanorod structure not only exposes enriched active sites, but also accelerates the electrolyte diffusion and bubble desorption. Therefore, NixSy@MnOxHy/NF exhibits exceptional bifunctional activity and stability for overall water splitting, with low overpotentials of 326 and 356 mV for OER at 100 and 500 mA cm^(–2), respectively, along with high stability of 150 h at 100 mA cm^(–2). Furthermore, for overall water splitting, it presents a low cell voltage of 1.529 V at 10 mA cm^(–2), accompanied by excellent stability at 100 mA cm^(–2) for 100 h. This work sheds a light on exploring highly active and stable bifunctional electrocatalysts by the interface engineering coupled with shell-protection strategy.
基金supported by the Natural Science Foundation of Zhejiang Province(LZ22C130001)the National Natural Science Foundation of China(32171887,and 52002028,and 52192610)+1 种基金the National Key Research and Development Project from Minister of Science&Technology(2021YFA0202704)Beijing Municipal Science&Technology Commission(Z171100002017017).
文摘Efficient utilization of electrostatic charges is paramount for numerous applications,from printing to kinetic energy harvesting.However,existing technologies predominantly focus on the static qualities of these charges,neglecting their dynamic capabilities as carriers for energy conversion.Herein,we report a paradigm-shifting strategy that orchestrates the swift transit of surface charges,generated through contact electrification,via a freely moving droplet.This technique ingeniously creates a bespoke charged surface which,in tandem with a droplet acting as a transfer medium to the ground,facilitates targeted charge displacement and amplifies electrical energy collection.The spontaneously generated electric field between the charged surface and needle tip,along with the enhanced water ionization under the electric field,proves pivotal in facilitating controlled charge transfer.By coupling the effects of charge self-transfer,contact electrification,and electrostatic induction,a dual-electrode droplet-driven(DD)triboelectric nanogenerator(TENG)is designed to harvest the water-related energy,exhibiting a two-orderof-magnitude improvement in electrical output compared to traditional single-electrode systems.Our strategy establishes a fundamental groundwork for efficient water drop energy acquisition,offering deep insights and substantial utility for future interdisciplinary research and applications in energy science.
基金the National Natural Science Foundation of China(Nos.51901059,1563003 and 11203009)。
文摘Producing highly efficient bifunctional catalyst for the generation of hydrogen and oxygen through overall water splitting is an emerging direction in electrocatalysis.Herein,a dandelion-like hierarchical NiMoP_(2)-Ni_(2)P(nanowire/nanoparticle)heterostructure was synthesized for efficient electrochemical water splitting.The NiMoP_(2)-Ni_(2)P heterostructures grown on carbon cloth as a freestanding integrated electrode exhibited excellent oxygen evolution reaction(OER)activity and hydrogen evolution reaction(HER)activities with low overpotentials(258 mV and 53 mV to reach 10 mA cm~(-2)for the OER and HER,respectively),and small Tafel slope(45 mV dec^(-1)and 58 mV dec^(-1)for the OER and HER,respectively).Moreover,the NiMoP_(2)-Ni_(2)P heterostructure can act as both anode and cathode catalysts for overall water splitting with low overall potential of 1.48 V at 10 mA cm~(-2).Density functional theory(DFT)combined with structural probes suggests that the amorphous heterogeneous interfaces play an essential role in enhanced catalytic performance.
基金This study was financially supported by the National Natural Science Foundation of China(51973079,51773075 and 21875084)the Project of Department of Scienceand Technology of Jilin Province,China(20190101013JH).
文摘Nowdays,electrocatalytic water splitting has been regarded as one of the most efficient means to approach the urgent energy crisis and environmental issues.However,to speed up the electrocatalytic conversion efficiency of their half reactions including hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),electrocatalysts are usually essential to reduce their kinetic energy barriers.Electrospun nanomaterials possess a unique one‐dimensional structure for outstanding electron and mass transportation,large specific surface area,and the possibilities of flexibility with the porous feature,which are good candidates as efficient electrocatalysts for water splitting.In this review,we focus on the recent research progress on the electrospun nanomaterials‐based electrocatalysts for HER,OER,and overall water splitting reaction.Specifically,the insights of the influence of the electronic modulation and interface engineering of these electrocatalysts on their electrocatalytic activities will be deeply discussed and highlighted.Furthermore,the challenges and development opportunities of the electrospun nanomaterials‐based electrocatalysts for water splitting are featured.Based on the achievements of the significantly enhanced performance from the electronic modulation and interface engineering of these electrocatalysts,full utilization of these materials for practical energy conversion is anticipated.
基金financially supported by the National Natural Science Foundation of China(U2002213)the Creative Project of Engineering Research Center of Alternative Energy Materials&Devices,Ministry of Education,Sichuan University(AEMD202207)+7 种基金the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials of Guangxi University(2022GXYSOF10)the Guangdong Colleges&Universities Characteristic Innovation Project(2021KTSCX263)the Guangdong Education&Scientific Research Project(2021GXJK535)the Guangzhou Panyu Polytechnic Science&Technology Project(2021KJ01)the East-Land Middle-aged and Young Backbone Teacher of Yunnan University(C176220200)the Yunnan Applied Basic Research Projects(202001BB050006,202001BB050007)the Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University(2019FY003025)the Double First Class University Plan(C176220100042)。
文摘Designing cost-effective and high-efficiency electrocatalysts is critical to the water splitting performance during hydrogen generation.Herein,we have developed Fe_(2)P-Co_(2)P heterostructure nanowire arrays with excellent lattice torsions and grain boundaries for highly efficient water splitting.According to the microstructural investigations and theoretical calculations,the lattice torsion interface not only contributes to the exposure of more active sites but also effectively tunes the adsorption energy of hydrogen/oxygen intermediates via the accumulation of charge redistribution.As a result,the Fe_(2)P-Co_(2)P heterostructure nanowire array exhibits exceptional bifunctional catalytic activity with overpotentials of 65 and 198 mV at 10 mA cm^(-2) for hydrogen and oxygen evolution reactions,respectively.Moreover,the Fe_(2)P-Co_(2)P/NF-assembled electrolyzer can deliver 10 mA cm^(-2) at an ultralow voltage of1.51 V while resulting in a high solar-to-hydrogen conversion efficiency of 19.8%in the solar-driven water electrolysis cell.
文摘Electrochemical （EC） reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique for chemical analysis, yet its application to EC reactions is hindered by the strong attenuation of infrared （IR） light in both electrodes and electrolytes. Here we demonstrate that by incorporating appropriate sub-wavelength plasmonic structures at the metal electrode, the IR field at the EC interface can be greatly enhanced via the excitation of surface plasmon. This scheme facilitates in situ vibrational spectroscopic studies, especially using the surface-specific sum-frequency generation technique.
基金the financial support of the National Natural Science Foundation of China (No. 21277091 & 51472159)the State Key Program of National Natural Science Foundation of China (No. 21436007)+1 种基金the Key Basic Research Projects of Science and Technology Commission of Shanghai (No. 14JC1403100)the Chenxing-SMG Young Scholar Project of Shanghai Jiao Tong University
文摘We have previously developed a new process of highly efficient conversion of COand water into formic acid with metallic Zn without the addition of catalyst, however, its mechanism is not clear, particularly in the catalytic role of Zn/ZnO interface. Herein, the autocatalytic role of Zn/ZnO interface formed in situ during the reduction of COinto formic acid with Zn in water was studied by combining high resolution transmission electron microscopy（HRTEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS） techniques and experimental data. The electron microscope results show that possible defects or dislocations formed on Zn/ZnO interface, in which plays a key role for Zn H-formation. Further XPS analyses indicate that oxygen vacancies on Zn/ZnO interface increased at short reaction times（less than 10 min）. These analyses and experimental results suggest that a highly efficient and rapid conversion of COand water into formic acid should involve an autocatalytic role of the Zn/ZnO interface formed in situ, particularly at the beginning of the reaction.
基金financially supported by the National Natural Science Foundation of China(No.22179014,21603019)program for the Hundred Talents Program of Chongqing University。
文摘The electronic structures and properties of electrocatalysts,which depend on the physicochemical structure and metallic element components,could significantly affect their electrocatalytic performance and their future applications in Zn-air battery(ZAB)and overall water splitting(OWS).Here,by combining vacancies and heterogeneous interfacial engineering,three-dimensional(3D)core-shell NiCoP/NiO heterostructures with dominated oxygen vacancies have been controllably in-situ grown on carbon cloth for using as highly efficient electrocatalysts toward hydrogen and oxygen electrochemical reactions.Theoretical calculation and electrochemical results manifest that the hybridization of NiCoP core with NiO shell produces a strong synergistic electronic coupling effect.The oxygen vacancy can enable the emergence of new electronic states within the band gap,crossing the Fermi levels of the two spin components and optimizing the local electronic structure.Besides,the hierarchical core-shell NiCoP/NiO nanoarrays also endow the catalysts with multiple exposed active sites,faster mass transfer behavior,optimized electronic strutures and improved electrochemical performance during ZAB and OWS applications.
基金This work was supported by Chines Academy of Scieuces（No.CMS-cx200305）,National Natural Science Foundation of China（NSFC No.20425309,No.20573117）and Chinese Ministry of Science and Technology （M0ST No.G1999075305）.
文摘Here we report a quantitative study of the orientational structure and motion of water molecule at the air/water interface. Analysis of Sum Frequency Generation （SFG） vibrational peak of the free O-H stretching band at 3700 cm^-1 in four experimental configurations showed that orientational motion of water molecule at air/water interface is libratory within a limited angular range. The free OH bond of the interracial water molecule is tilted around 33°from the interface normal and the orientational distribution or motion width is less than 15°. This picture is significantly different from the previous conclusion that the interracial water molecule orientation varies over a broad range within the ultrafast vibrational relaxation time, the only direct experimental study concluded for ultrafast and broad orient, ational motion of a liquid interface by Wei et al. （Phys. Rev. Lett. 86, 4799, （2001）） using single SFG experimental configuration.
文摘Studies on nonlinear behavior at oil/water interface membrane were performed. This system showed rhythmic oscillations and chaos of electrical potential in a given concentration domain. The nonlinear behavior response at the liquid membrane apparently resembled that of biological chemoreceptive membrane. The possibility of developing a new type of chemical sensor with the ability to simulate substance equilibrium in living organisms was suggested in the paper.
文摘High-speed planing crafts have successfully evolved through developments in the last several decades.Classical approaches such as inviscid potential flow–based methods and the empirically based Savitsky method provide general understanding for practical design.However,sometimes such analyses suffer inaccuracies since the air–water interface effects,especially in the transition phase,are not fully accounted for.Hence,understanding the behaviour at the transition speed is of fundamental importance for the designer.The fluid forces in planing hulls are dominated by phenomena such as flow separation at various discontinuities viz.,knuckles,chines and transom,with resultant spray generation.In such cases,the application of potential theory at high speeds introduces limitations.This paper investigates the simulation of modelling of the pre-planing behaviour with a view to capturing the air–water interface effects,with validations through experiments to compare the drag,dynamic trim and wetted surface area.The paper also brings out the merits of gridding strategies to obtain reliable results especially with regard to spray generation due to the air–water interface effects.The verification and validation studies serve to authenticate the use of the multi-gridding strategies on the basis of comparisons with simulations using model tests.It emerges from the study that overset/chimera grids give better results compared with single unstructured hexahedral grids.Two overset methods are investigated to obtain reliable estimation of the dynamic trim and drag,and their ability to capture the spray resulting from the air–water interaction.The results demonstrate very close simulation of the actual flow kinematics at steady-speed conditions in terms of spray at the air–water interface,drag at the pre-planing and full planing range and dynamic trim angles.
