A cluster of serpentinite bodies has been recognized tectonically emplaced within the greenschist-amphibolite-facies metamorphic terrane in Hong'an,western Dabie orogen,central China.Two types of serpentinites are...A cluster of serpentinite bodies has been recognized tectonically emplaced within the greenschist-amphibolite-facies metamorphic terrane in Hong'an,western Dabie orogen,central China.Two types of serpentinites are identified on the basis of integrated petrographic,mineralogical and geochemical study.The first type,represented by Yinshanzhai serpentinite complex(Group 1)comprises heterogeneous lithology as a massive serpentinite matrix“intruded”by antigoriteenriched serpentinite lenses.They are both pseudomorphic textured with different mineral assemblages indicating an increasing temperature-pressure condition.Serpentinite matrix(Group 1a)is chemically characterized by high MgO/SiO_(2)and low Al_(2)O_(3)/SiO_(2),Ti and Ca contents,suggesting a depleted mantle wedge origin.The coexistence of compositionally-heterogeneous chromite with highCr^(#)(0.78-0.96)and intermediate-Cr^(#)(0.59-0.70)pristine cores indicates extensive mantle melting.Meanwhile,extremely high Fo olivine relicts(96-97)with considerably higher MnO and lower NiO contents than mantle olivine indicate that they are metamorphic products from serpentine decomposition.Accordingly,we propose that Yinshanzhai serpentinite complex experienced two distinct episodes of hydration.The serpentinite lenses(Group 1b)show higher SiO_(2)and lower MgO concentrations.Nevertheless,the trace elements of groups 1a and 1b are consistent:U-shaped REE patterns,positive Eu anomalies and enrichment of LILE(i.e.,Cs,U)are all identified as forearc properties.They are affected by reducing slab-derived fluids in forearc mantle,with f_(O2)of 1 to 2 logarithmic units below f_(O2)of fayalite-magnetite-quartz buffer(FMQ-2~FMQ-1).The second type is antigorite-serpentinites(Group2)represented by Ximaoshan and Wangchunwan blocks.They are non-pseudomorphic,with no primary framework silicate surviving.Fertile compositions(i.e.,higher Al_(2)O_(3)and Al_(2)O_(3)/SiO_(2),nearly flat REE patterns)and conjoint enrichment of LILE with HFSE suggest melt/rock interaction.Negative Ce,Eu anomalies,and enriched U relative to alkaline elements demonstrate interactions with more oxidized seawater or seafloor fluids(FMQ~FMQ-1).Remarkable Sr negative anomalies may be attributed to Sr release during lizardite/antigorite transition in subduction zone,indicating interaction with low-Sr slab fluids.We propose that Group 2 serpentinites originate either from mantle wedge or abyssal peridotites,refertilized by mantle melts,then hydrated in seafloor or shallow forearc and entrapped into subduction channel.Combined with geochronology and tectonic constraints of associated eclogites in Hong'an terrane,the two types of serpentinites may correlate with subduction of different oceanic basins during the late Paleozoic and/or Proterozoic eras.It raises possibility of defining an ophiolitic setting in Hong'an Orogen for which further evidence is required.展开更多
Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power plants.More accurate models on the operating mechanism of the seals are ...Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power plants.More accurate models on the operating mechanism of the seals are needed to help improve their performance.The thermal fluid–solid interaction（TFSI）mechanism of the hydrostatic seal is investigated in this study.Numerical models of the flow field and seal assembly are developed.Based on the mechanism for the continuity condition of the physical quantities at the fluid–solid interface,an on-line numerical TFSI model for the hydrostatic mechanical seal is proposed using an iterative coupling method.Dynamic mesh technology is adopted to adapt to the changing boundary shape.Experiments were performed on a test rig using a full-size test seal to obtain the leakage rate as a function of the differential pressure.The effectiveness and accuracy of the TFSI model were verified by comparing the simulation results and experimental data.Using the TFSI model,the behavior of the seal is presented,including mechanical and thermal deformation,and the temperature field.The influences of the rotating speed and differential pressure of the sealing device on the temperature field,which occur widely in the actual use of the seal,are studied.This research proposes an on-line and assembly-based TFSI model for hydrostatic mechanical face seals,and the model is validated by full-sized experiments.展开更多
Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production eff...Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production efficiency of shale oil resources.Effectively stimulating oil shale reservoirs remains a challenging and active research topic.This investigation employed shale specimens obtained from the Longmaxi Formation.Scanning electron microscopy,fluid injection experiments,and fluid-structure interaction simulations were used to comprehensively analyze structural changes and fluid flow behavior under high temperatures from microscopic to macroscopic scales.Experimental results indicate that the temperature has little effect on the structure and permeability of shale before 300℃.However,there are two threshold temperatures within the range of 300 to 600℃that have significant effects on the structure and permeability of oil shale.The first threshold temperature is between 300 and 400℃,which causes the oil shale porosity,pore-fracture ratio,and permeability begin to increase.This is manifested by the decrease in micropores and mesopores,the increase in macropores,and the formation of a large number of isolated pores and fissures within the shale.The permeability increases but not significantly.The second threshold temperature is between 500 and 600℃,which increases the permeability of oil shale significantly.During this stage,micropores and mesopores are further reduced,and macropores are significantly enlarged.A large number of connected and penetrated pores and fissures are formed.More numerous and thicker streamlines appear inside the oil shale.The experimental results demonstrate that high temperatures significantly alter the microstructure and permeability of oil shale.At the same time,the experimental results can provide a reference for the research of in-situ heating techniques in oil shale reservoir transformation.展开更多
Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. On...Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. Only elastic deformations of hydraulic reciprocating seals were discussed, and hydrodynamic effects were neglected in many studies. The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals, and few of these models had been simultaneously validated through experiments. By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal, a numerical fluid-solid interaction model consisting of fluid lubrication, contact mechanics, asperity contact and elastic deformation analyses is constructed with an iterative procedure. With the SRV friction and wear tester, the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal. The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition. The experimental result is used to validate the fluid-solid interaction model. Based on the model, The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction, mixed lubrication and full film lubrication conditions, including of the contact pressure, film thickness, friction coefficient, liquid film pressure and viscous shear stress in the sealing zone. The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal, and can also be widely used to study other hydraulic reciprocating seals.展开更多
An integrated fluid-thermal-structural analysis approach is presented. In this approach, the heat conduction in a solid is coupled with the heat convection in the viscous flow of the fluid resulting in the thermal str...An integrated fluid-thermal-structural analysis approach is presented. In this approach, the heat conduction in a solid is coupled with the heat convection in the viscous flow of the fluid resulting in the thermal stress in the solid. The fractional four-step finite element method and the streamline upwind Petrov-Galerkin （SUPG） method are used to analyze the viscous thermal flow in the fluid. Analyses of the heat transfer and the thermal stress in the solid axe performed by the Galerkin method. The second-order semi- implicit Crank-Nicolson scheme is used for the time integration. The resulting nonlinear equations are lineaxized to improve the computational efficiency. The integrated analysis method uses a three-node triangular element with equal-order interpolation functions for the fluid velocity components, the pressure, the temperature, and the solid displacements to simplify the overall finite element formulation. The main advantage of the present method is to consistently couple the heat transfer along the fluid-solid interface. Results of several tested problems show effectiveness of the present finite element method, which provides insight into the integrated fluid-thermal-structural interaction phenomena.展开更多
For solid-fluid interaction, one of the phase-density equations in diffuse interface models is degenerated to a "0 = 0" equation when the volume fraction of a certain phase takes the value of zero or unity. ...For solid-fluid interaction, one of the phase-density equations in diffuse interface models is degenerated to a "0 = 0" equation when the volume fraction of a certain phase takes the value of zero or unity. This is because the conservative variables in phasedensity equations include volume fractions. The degeneracy can be avoided by adding an artificial quantity of another material into the pure phase. However, nonphysical waves,such as shear waves in fluids, are introduced by the artificial treatment. In this paper,a transport diffuse interface model, which is able to treat zero/unity volume fractions, is presented for solid-fluid interaction. In the proposed model, a new formulation for phase densities is derived, which is unrelated to volume fractions. Consequently, the new model is able to handle zero/unity volume fractions, and nonphysical waves caused by artificial volume fractions are prevented. One-dimensional and two-dimensional numerical tests demonstrate that more accurate results can be obtained by the proposed model.展开更多
Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility ...Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.展开更多
Characterization and optimization of physical and chemical properties of drilling fluids are critical for the efficiency and success of drilling operations.In particular,maintaining the optimal levels of solids conten...Characterization and optimization of physical and chemical properties of drilling fluids are critical for the efficiency and success of drilling operations.In particular,maintaining the optimal levels of solids content is essential for achieving the most effective fluid performance.Proper management of solids content also reduces the risk of tool failures.Traditional solids content analysis methods,such as retort analysis,require substantial human intervention and time,which can lead to inaccuracies,time-management issues,and increased operational risks.In contrast to human-intensive methods,machine learning may offer a viable alternative for solids content estimation due to its pattern-recognition capability.In this study,a large set of laboratory reports of drilling-fluid analyses from 130 oil wells around the world were compiled to construct a comprehensive data set.The relationships among various rheological parameters were analyzed using statistical methods and machine learning algorithms.Several machine learning algorithms of diverse classes,namely linear(linear regression,ridge regression,and ElasticNet regression),kernel-based(support vector machine)and ensemble tree-based(gradient boosting,XGBoost,and random forests)algorithms,were trained and tuned to estimate solids content from other readily available drilling fluid properties.Input variables were kept consistent across all models for interpretation and comparison purposes.In the final stage,different evaluation metrics were employed to evaluate and compare the performance of different classes of machine learning models.Among all algorithms tested,random forests algorithm was found to be the best predictive model resulting in consistently high accuracy.Further optimization of the random forests model resulted in a mean absolute percentage error(MAPE)of 3.9%and 9.6%and R^(2) of 0.99 and 0.93 for the training and testing sets,respectively.Analysis of residuals,their histograms and Q-Q normality plots showed Gaussian distributions with residuals that are scattered around a mean of zero within error ranges of±1%and±4%,for training and testing,respectively.The selected model was further validated by applying the rheological measurements from mud samples taken from an offshore well from the Gulf of Mexico.The model was able to estimate total solids content in those four mud samples with an average absolute error of 1.08% of total solids content.The model was then used to develop a web-based graphical-user-interface(GUI)application,which can be practically used at the rig site by engineers to optimize drilling fluid programs.The proposed model can complement automation workflows that are designed to measure fundamental rheological properties in real time during drilling operations.While a standard retort test can take approximately 2 h at the rig site,such kind of real-time estimations can help the rig personnel to timely optimize drilling fluids,with a potential of saving 2920 man-hours in a given year for a single drilling rig.展开更多
Based on atomic crystal configurations,we studied many-body interaction properties of face-centered cubic(fcc)solid argon(Ar)within the atomic distance range of 2.0A to 3.6A at T=300 K.The resulting EOS can accurately...Based on atomic crystal configurations,we studied many-body interaction properties of face-centered cubic(fcc)solid argon(Ar)within the atomic distance range of 2.0A to 3.6A at T=300 K.The resulting EOS can accurately describe the compression behavior of solid Ar under the experimentally investigated pressure range(0~114GPa).Statistically,903(Ar)2 clusters were identified,corresponding to 12 distinct geometric configurations,861(Ar)3 clusters correspond to 25 distinct geometric configurations,816(Ar)4clusters correspond to 27 distinct geometric configurations,and the calculation results exhibited good convergence.For comparative purposes,the EOS of fcc solid Ar was also calculated using a two-body potential-only approach,which showed excellent agreement with experimental data under relevant pressures.Incorporating three-body terms extended the EOS accuracy to 80 GPa,while the inclusion of four-body terms further improved the precision up to 114 GPa.Higher-order many-body terms are expected to enable accurate interpretation of experimental phenomena in solid Ar above 114 GPa.In addition,when the molar volume is reduced to a fixed value,the zero-point vibration pressure has already reached a certain proportion,then it must be considered and cannot be ignored.This study provides a reliable theoretical model for the study of high-pressure properties and zero-point energy of rare gas solids.展开更多
Compared to currently commercialized lithium-ion batteries,which use flammable organic liquid electrolytes and low-energy-density graphite anodes,solid-state lithium-metal batteries(SSLMBs)offer enhanced energy densit...Compared to currently commercialized lithium-ion batteries,which use flammable organic liquid electrolytes and low-energy-density graphite anodes,solid-state lithium-metal batteries(SSLMBs)offer enhanced energy density and improved safety,making them promising alternatives for next-generation rechargeable batteries[1].As a crucial component of these batteries,solid-state electrolytes—divided into inorganic solid ceramic electrolytes(SCEs)and organic solid polymer electrolytes(SPEs)—are vital for lithium-ion transport and inhibiting lithium dendrite growth.Among them,SCEs exhibit high ionic conductivity,excellent mechanical properties,and outstanding electrochemical and thermal stability.Nevertheless,their brittleness,interfacial challenges with electrodes,and the requirement for high stacking pressure during battery operation significantly hinder their scalable application.In comparison,SPEs are more favourable for manufacturing due to their flexibility and good interfacial compatibility with electrodes[2].Despite these advantages,SPEs still face significant challenges in achieving practical application.Firstly,typical SPEs,such as poly(ethylene oxide)(PEO),poly(vinylidene fluoride)(PVDF),and poly(ethylene glycol)diacrylate(PEGDA),are characterized by high crystallinity,which causes polymer chains to be tightly packed and rigid.This restricts the segmental motion within the SPEs,resulting in low ionic conductivity.Secondly,compared to lithium ions,anions with large ionic radii and low charge density typically form weaker interactions with the polymer chains,which facilitates their mobility and results in a low lithium-ion transference number(tt).Thirdly,the weak interactions between polymer chains in typical SPEs lead to a low elastic modulus,which in turn compromises their poor mechanical strength.展开更多
With the advent of ultrashort high intensity laser pulses, laser absorption during the laser–solid interactions has received significant attention over the last two decades since it is related to a variety of applica...With the advent of ultrashort high intensity laser pulses, laser absorption during the laser–solid interactions has received significant attention over the last two decades since it is related to a variety of applications of high intensity lasers,including the hot electron production for fast ignition of fusion targets, table-top bright X-ray and gamma-ray sources,ion acceleration, compact neutron sources, and generally the creation of high energy density matters. Normally, some absorption mechanisms found for nanosecond long laser pulses also appear for ultrashort laser pulses. The peculiar aspects with ultrashort laser pulses are that their absorption depends significantly on the preplasma condition and the initial target structures. Meanwhile, relativistic nonlinearity and ponderomotive force associated with the laser pulses lead to new mechanisms or phenomena, which are usually not found with nanosecond long pulses. In this paper, we present an overview of the recent progress on the major absorption mechanisms in intense laser–solid interactions, where emphasis is paid to our related theory and simulation studies.展开更多
This paper is devoted to the two-dimensional nonlinear modeling of the fluid-solid interaction (FSI) between fabric and air flow, which is based on the Automatic Incremental Dynamic Nonlinear Analysis (AIDNA)-FSI prog...This paper is devoted to the two-dimensional nonlinear modeling of the fluid-solid interaction (FSI) between fabric and air flow, which is based on the Automatic Incremental Dynamic Nonlinear Analysis (AIDNA)-FSI program in order to study the dynamic bending features of fabrics in a specific air flow filed. The computational fluid dynamics (CFD) model for flow and the finite element model (FEM) for fabric was set up to constitute an FSI model in which the geometric nonlinear behavior and the dynamic stress-strain variation of the relatively soft fabric material were taken into account. Several FSI cases with different time-dependent wind load and the model frequency analysis for fabric were carried out. The dynamic response of fabric and the distribution of fluid variables were investigated. The results of numerical simulation and experiments fit quite well. Hence, this work contributes to the research of modeling the dynamic bending behavior of fabrics in air field.展开更多
Problems involving fluid flexible-structure interactions(FFSI)are ubiquitous in engineering and sciences.Peskin’s immersed boundary(IB)method is the first framework for modeling and simulation of such problems.This p...Problems involving fluid flexible-structure interactions(FFSI)are ubiquitous in engineering and sciences.Peskin’s immersed boundary(IB)method is the first framework for modeling and simulation of such problems.This paper addresses a three-dimensional extension of the IB framework for non-Newtonian fluids which include power-law fluid,Oldroyd-B fluid,and FENE-P fluid.The motion of the non-Newtonian fluids are modelled by the lattice Boltzmann equations(D3Q19 model).The differential constitutive equations of Oldroyd-B and FENE-P fluids are solved by the D3Q7 model.Numerical results indicate that the new method is first-order accurate and conditionally stable.To show the capability of the new method,it is tested on three FFSI toy problems:a power-law fluid past a flexible sheet fixed at its midline,a flexible sheet being flapped periodically at its midline in an Oldroyd-B fluid,and a flexible sheet being rotated at one edge in a FENE-P fluid.展开更多
Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-p...Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.展开更多
Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for nume...Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for numerical simulation based on computational fluid dynamics and nonlinear finite element analysis methods. The typical results of the numerical simulation and wind tunnel experiment, including the overall lift and deformation, are in good agreement with each other. The results obtained indicate that the effect of fluid-structure interaction is noticeable and should be considered for non-rigid airships. Flow- induced deformation can further intensify the upward lift force and pitching moment, which can lead to a large deformation. Under a wind speed of 15 m/s, the lift force of the non-rigid model is increased to approximatelv 60% compared with that of the rigid model under a high angle of attack.展开更多
Composite solid-state electrolytes(CSEs)have garnered significant attention for nextgeneration energy storage owing to their inherent safety features compared with those of their liquid counterparts.However,their prac...Composite solid-state electrolytes(CSEs)have garnered significant attention for nextgeneration energy storage owing to their inherent safety features compared with those of their liquid counterparts.However,their practical deployment remains hindered by sluggish lithium-ion transport kinetics and interfacial instability.Herein,we introduced a bimetal oxide enhanced strategy for oxygen-vacancy-engineered double perovskite nanofillers(PrBaCoFeO_(5+δ)(PBCF))to address these challenges in polyethylene oxide(PEO)-based CSEs.The strong Lewis acid-base coordination between Co^(3+)/Fe^(3+)sites on PBCF and ether oxygen groups in PEO effectively suppresses the polymer-chain crystallization while creating continuous Li^(+)conduction pathways.Importantly,the abundant oxygen vacancies serve as catalytic centers to decompose lithium bis(trifluoromethanesulfonyl)imide(LiTFSI),thereby forming a robust organic-inorganic hybrid solid electrolyte interphase(SEI).Consequently,the prepared PEO-LiTFSI-PBCF CSE achieves an improved Li^(+)ionic conductivity of 2.76×10^(-4) S·cm^(-1)(30℃)and an elevated Li^(+)transference number(0.54).The Li||Li symmetric cell exhibits impressive lithium plating/stripping ability(>6000 h at 0.1 mA·cm^(-2))and practical viability in Li||LiFePO_(4)full cells with 90.1% capacity retention after 500 cycles at 30℃(0.3 C).This defect engineering strategy provides new insights into the construction of fast and stable Li^(+)transport channels in polymer solid-state electrolytes,paving the way for high-energy-density all-solid-state lithium metal batteries.展开更多
Fluid and solid simulation is to generate a realistic simulation of fluids and solids,in particular for the fluids such as water and smoke,with computation of Euler equations or Navier-Stokes equations conducted to go...Fluid and solid simulation is to generate a realistic simulation of fluids and solids,in particular for the fluids such as water and smoke,with computation of Euler equations or Navier-Stokes equations conducted to govern the real fluid physics.Fluid simulation is an important field by its wide applications in many fields and industries,such as film and game simulation,weather forecasting,natural disaster simulation and protection,simulation in maritime and aviation.There are basically two main categories of methods for fluid simulation,data-driven methods and physically-based methods.The data-driven models establish a direct mapping between variables and extract their relationship from historically measured data by the algorithms developed in the fields of statistics,computational intelligence,machine learning,and data mining.展开更多
CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mec...CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mechanical stabilities. Deep insights into the mechanism of stereocomplexation are of particular importance to the design and manufacture of new promising and sustainable polycarbonates with enhanced physicochemical properties. Our solid-state NMR experiments linking with DFT computations clearly reveal the specific chain-chain interactions in a typical stereocomplexed poly（4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0] octane carbonate）（PCXC）.13C CP/MAS NMR,1H DUMBO MAS NMR and 13C/1H relaxation-time measurements indicate that the formation of stereocomplex reduces the local mobilities of carbonyl, methine and methylene groups in each chain of PCXC significantly. Through a combination of two-dimensional 1H-13C HETCOR NMR and DFT calculation analysis, the cis-/trans-conformations and packing models of PCXC chains in the amorphous, enantionpure isotactic and stereocomplexed polycarbonates are identified. The splitting of 13C and 1H NMR chemical shifts of methine groups in the backbone carbon region demonstrates the ordered interlock interactions between the R-and S-chain in the stereocomplexed PCXC.展开更多
基金funded by the National Natural Science Foundation of China(No.42130309)China Geological Survey(Nos.DD20160030,DD20190050)。
文摘A cluster of serpentinite bodies has been recognized tectonically emplaced within the greenschist-amphibolite-facies metamorphic terrane in Hong'an,western Dabie orogen,central China.Two types of serpentinites are identified on the basis of integrated petrographic,mineralogical and geochemical study.The first type,represented by Yinshanzhai serpentinite complex(Group 1)comprises heterogeneous lithology as a massive serpentinite matrix“intruded”by antigoriteenriched serpentinite lenses.They are both pseudomorphic textured with different mineral assemblages indicating an increasing temperature-pressure condition.Serpentinite matrix(Group 1a)is chemically characterized by high MgO/SiO_(2)and low Al_(2)O_(3)/SiO_(2),Ti and Ca contents,suggesting a depleted mantle wedge origin.The coexistence of compositionally-heterogeneous chromite with highCr^(#)(0.78-0.96)and intermediate-Cr^(#)(0.59-0.70)pristine cores indicates extensive mantle melting.Meanwhile,extremely high Fo olivine relicts(96-97)with considerably higher MnO and lower NiO contents than mantle olivine indicate that they are metamorphic products from serpentine decomposition.Accordingly,we propose that Yinshanzhai serpentinite complex experienced two distinct episodes of hydration.The serpentinite lenses(Group 1b)show higher SiO_(2)and lower MgO concentrations.Nevertheless,the trace elements of groups 1a and 1b are consistent:U-shaped REE patterns,positive Eu anomalies and enrichment of LILE(i.e.,Cs,U)are all identified as forearc properties.They are affected by reducing slab-derived fluids in forearc mantle,with f_(O2)of 1 to 2 logarithmic units below f_(O2)of fayalite-magnetite-quartz buffer(FMQ-2~FMQ-1).The second type is antigorite-serpentinites(Group2)represented by Ximaoshan and Wangchunwan blocks.They are non-pseudomorphic,with no primary framework silicate surviving.Fertile compositions(i.e.,higher Al_(2)O_(3)and Al_(2)O_(3)/SiO_(2),nearly flat REE patterns)and conjoint enrichment of LILE with HFSE suggest melt/rock interaction.Negative Ce,Eu anomalies,and enriched U relative to alkaline elements demonstrate interactions with more oxidized seawater or seafloor fluids(FMQ~FMQ-1).Remarkable Sr negative anomalies may be attributed to Sr release during lizardite/antigorite transition in subduction zone,indicating interaction with low-Sr slab fluids.We propose that Group 2 serpentinites originate either from mantle wedge or abyssal peridotites,refertilized by mantle melts,then hydrated in seafloor or shallow forearc and entrapped into subduction channel.Combined with geochronology and tectonic constraints of associated eclogites in Hong'an terrane,the two types of serpentinites may correlate with subduction of different oceanic basins during the late Paleozoic and/or Proterozoic eras.It raises possibility of defining an ophiolitic setting in Hong'an Orogen for which further evidence is required.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2009CB724304)National Key Technology R&D Program(Grant No.2011BAF09B05)National Natural Science Foundation of China(Grant No.50975157)
文摘Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power plants.More accurate models on the operating mechanism of the seals are needed to help improve their performance.The thermal fluid–solid interaction（TFSI）mechanism of the hydrostatic seal is investigated in this study.Numerical models of the flow field and seal assembly are developed.Based on the mechanism for the continuity condition of the physical quantities at the fluid–solid interface,an on-line numerical TFSI model for the hydrostatic mechanical seal is proposed using an iterative coupling method.Dynamic mesh technology is adopted to adapt to the changing boundary shape.Experiments were performed on a test rig using a full-size test seal to obtain the leakage rate as a function of the differential pressure.The effectiveness and accuracy of the TFSI model were verified by comparing the simulation results and experimental data.Using the TFSI model,the behavior of the seal is presented,including mechanical and thermal deformation,and the temperature field.The influences of the rotating speed and differential pressure of the sealing device on the temperature field,which occur widely in the actual use of the seal,are studied.This research proposes an on-line and assembly-based TFSI model for hydrostatic mechanical face seals,and the model is validated by full-sized experiments.
基金supported by the Chongqing Natural Science Foundation of Chongqing,China(No.CSTB2022NSCQ-MSX0333)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202401205)+1 种基金Chongqing Three Gorges University Graduate Research and Innovation Project Funding(No.YJSKY24045)Chongqing Engineering Research Center of Disaster Prevention&Control for Banks and Structures in Three Gorges Reservoir Area(No.SXAPGC24YB14,No.SXAPGC24YB03,No.SXAPGC24YB12)。
文摘Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production efficiency of shale oil resources.Effectively stimulating oil shale reservoirs remains a challenging and active research topic.This investigation employed shale specimens obtained from the Longmaxi Formation.Scanning electron microscopy,fluid injection experiments,and fluid-structure interaction simulations were used to comprehensively analyze structural changes and fluid flow behavior under high temperatures from microscopic to macroscopic scales.Experimental results indicate that the temperature has little effect on the structure and permeability of shale before 300℃.However,there are two threshold temperatures within the range of 300 to 600℃that have significant effects on the structure and permeability of oil shale.The first threshold temperature is between 300 and 400℃,which causes the oil shale porosity,pore-fracture ratio,and permeability begin to increase.This is manifested by the decrease in micropores and mesopores,the increase in macropores,and the formation of a large number of isolated pores and fissures within the shale.The permeability increases but not significantly.The second threshold temperature is between 500 and 600℃,which increases the permeability of oil shale significantly.During this stage,micropores and mesopores are further reduced,and macropores are significantly enlarged.A large number of connected and penetrated pores and fissures are formed.More numerous and thicker streamlines appear inside the oil shale.The experimental results demonstrate that high temperatures significantly alter the microstructure and permeability of oil shale.At the same time,the experimental results can provide a reference for the research of in-situ heating techniques in oil shale reservoir transformation.
基金supported by National Basic Research Program of China(973 Program,Grant No. 2009CB724304)Key Research Program of the State Key Laboratory of Tribology of Tsinghua University,China (Grant No. SKLT08A06)National Natural Science Foundation of China(Grant No. 50975157)
文摘Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. Only elastic deformations of hydraulic reciprocating seals were discussed, and hydrodynamic effects were neglected in many studies. The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals, and few of these models had been simultaneously validated through experiments. By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal, a numerical fluid-solid interaction model consisting of fluid lubrication, contact mechanics, asperity contact and elastic deformation analyses is constructed with an iterative procedure. With the SRV friction and wear tester, the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal. The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition. The experimental result is used to validate the fluid-solid interaction model. Based on the model, The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction, mixed lubrication and full film lubrication conditions, including of the contact pressure, film thickness, friction coefficient, liquid film pressure and viscous shear stress in the sealing zone. The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal, and can also be widely used to study other hydraulic reciprocating seals.
基金the National Metal and Materials Technology Centerthe Thailand Research Fund+1 种基金the Office of Higher Education Commissionthe Chulalongkorn University for supporting the present research
文摘An integrated fluid-thermal-structural analysis approach is presented. In this approach, the heat conduction in a solid is coupled with the heat convection in the viscous flow of the fluid resulting in the thermal stress in the solid. The fractional four-step finite element method and the streamline upwind Petrov-Galerkin （SUPG） method are used to analyze the viscous thermal flow in the fluid. Analyses of the heat transfer and the thermal stress in the solid axe performed by the Galerkin method. The second-order semi- implicit Crank-Nicolson scheme is used for the time integration. The resulting nonlinear equations are lineaxized to improve the computational efficiency. The integrated analysis method uses a three-node triangular element with equal-order interpolation functions for the fluid velocity components, the pressure, the temperature, and the solid displacements to simplify the overall finite element formulation. The main advantage of the present method is to consistently couple the heat transfer along the fluid-solid interface. Results of several tested problems show effectiveness of the present finite element method, which provides insight into the integrated fluid-thermal-structural interaction phenomena.
基金Project supported by the National Natural Science Foundation of China(Nos.11702029,11771054,U1730118,91852207,and 11801036)the China Postdoctoral Science Foundation(No.2016M600967)
文摘For solid-fluid interaction, one of the phase-density equations in diffuse interface models is degenerated to a "0 = 0" equation when the volume fraction of a certain phase takes the value of zero or unity. This is because the conservative variables in phasedensity equations include volume fractions. The degeneracy can be avoided by adding an artificial quantity of another material into the pure phase. However, nonphysical waves,such as shear waves in fluids, are introduced by the artificial treatment. In this paper,a transport diffuse interface model, which is able to treat zero/unity volume fractions, is presented for solid-fluid interaction. In the proposed model, a new formulation for phase densities is derived, which is unrelated to volume fractions. Consequently, the new model is able to handle zero/unity volume fractions, and nonphysical waves caused by artificial volume fractions are prevented. One-dimensional and two-dimensional numerical tests demonstrate that more accurate results can be obtained by the proposed model.
基金supported by funds from the National Key Research and Development Program of China(Grant No.2024YFF0807302)National Natural Science Foundation of China(42273043,42173003)the International Visiting Professorship of USTC(2024BVR23).
文摘Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.
文摘Characterization and optimization of physical and chemical properties of drilling fluids are critical for the efficiency and success of drilling operations.In particular,maintaining the optimal levels of solids content is essential for achieving the most effective fluid performance.Proper management of solids content also reduces the risk of tool failures.Traditional solids content analysis methods,such as retort analysis,require substantial human intervention and time,which can lead to inaccuracies,time-management issues,and increased operational risks.In contrast to human-intensive methods,machine learning may offer a viable alternative for solids content estimation due to its pattern-recognition capability.In this study,a large set of laboratory reports of drilling-fluid analyses from 130 oil wells around the world were compiled to construct a comprehensive data set.The relationships among various rheological parameters were analyzed using statistical methods and machine learning algorithms.Several machine learning algorithms of diverse classes,namely linear(linear regression,ridge regression,and ElasticNet regression),kernel-based(support vector machine)and ensemble tree-based(gradient boosting,XGBoost,and random forests)algorithms,were trained and tuned to estimate solids content from other readily available drilling fluid properties.Input variables were kept consistent across all models for interpretation and comparison purposes.In the final stage,different evaluation metrics were employed to evaluate and compare the performance of different classes of machine learning models.Among all algorithms tested,random forests algorithm was found to be the best predictive model resulting in consistently high accuracy.Further optimization of the random forests model resulted in a mean absolute percentage error(MAPE)of 3.9%and 9.6%and R^(2) of 0.99 and 0.93 for the training and testing sets,respectively.Analysis of residuals,their histograms and Q-Q normality plots showed Gaussian distributions with residuals that are scattered around a mean of zero within error ranges of±1%and±4%,for training and testing,respectively.The selected model was further validated by applying the rheological measurements from mud samples taken from an offshore well from the Gulf of Mexico.The model was able to estimate total solids content in those four mud samples with an average absolute error of 1.08% of total solids content.The model was then used to develop a web-based graphical-user-interface(GUI)application,which can be practically used at the rig site by engineers to optimize drilling fluid programs.The proposed model can complement automation workflows that are designed to measure fundamental rheological properties in real time during drilling operations.While a standard retort test can take approximately 2 h at the rig site,such kind of real-time estimations can help the rig personnel to timely optimize drilling fluids,with a potential of saving 2920 man-hours in a given year for a single drilling rig.
基金sponsored by the Youth Talent(team)project of Gansu Province(Grant No.2025QNTD12)the Natural ScienceFoundation of Gansu Province(Grant No.25JRRM001,23JRRM0755).
文摘Based on atomic crystal configurations,we studied many-body interaction properties of face-centered cubic(fcc)solid argon(Ar)within the atomic distance range of 2.0A to 3.6A at T=300 K.The resulting EOS can accurately describe the compression behavior of solid Ar under the experimentally investigated pressure range(0~114GPa).Statistically,903(Ar)2 clusters were identified,corresponding to 12 distinct geometric configurations,861(Ar)3 clusters correspond to 25 distinct geometric configurations,816(Ar)4clusters correspond to 27 distinct geometric configurations,and the calculation results exhibited good convergence.For comparative purposes,the EOS of fcc solid Ar was also calculated using a two-body potential-only approach,which showed excellent agreement with experimental data under relevant pressures.Incorporating three-body terms extended the EOS accuracy to 80 GPa,while the inclusion of four-body terms further improved the precision up to 114 GPa.Higher-order many-body terms are expected to enable accurate interpretation of experimental phenomena in solid Ar above 114 GPa.In addition,when the molar volume is reduced to a fixed value,the zero-point vibration pressure has already reached a certain proportion,then it must be considered and cannot be ignored.This study provides a reliable theoretical model for the study of high-pressure properties and zero-point energy of rare gas solids.
基金supported by the University of Wollongong,Wollongong,Australiafinancial support from the National Natural Science Foundation of China(22272086)Natural Science Foundation of Sichuan Province(2023NSFSC0009).
文摘Compared to currently commercialized lithium-ion batteries,which use flammable organic liquid electrolytes and low-energy-density graphite anodes,solid-state lithium-metal batteries(SSLMBs)offer enhanced energy density and improved safety,making them promising alternatives for next-generation rechargeable batteries[1].As a crucial component of these batteries,solid-state electrolytes—divided into inorganic solid ceramic electrolytes(SCEs)and organic solid polymer electrolytes(SPEs)—are vital for lithium-ion transport and inhibiting lithium dendrite growth.Among them,SCEs exhibit high ionic conductivity,excellent mechanical properties,and outstanding electrochemical and thermal stability.Nevertheless,their brittleness,interfacial challenges with electrodes,and the requirement for high stacking pressure during battery operation significantly hinder their scalable application.In comparison,SPEs are more favourable for manufacturing due to their flexibility and good interfacial compatibility with electrodes[2].Despite these advantages,SPEs still face significant challenges in achieving practical application.Firstly,typical SPEs,such as poly(ethylene oxide)(PEO),poly(vinylidene fluoride)(PVDF),and poly(ethylene glycol)diacrylate(PEGDA),are characterized by high crystallinity,which causes polymer chains to be tightly packed and rigid.This restricts the segmental motion within the SPEs,resulting in low ionic conductivity.Secondly,compared to lithium ions,anions with large ionic radii and low charge density typically form weaker interactions with the polymer chains,which facilitates their mobility and results in a low lithium-ion transference number(tt).Thirdly,the weak interactions between polymer chains in typical SPEs lead to a low elastic modulus,which in turn compromises their poor mechanical strength.
基金Project supported by the National Basic Research Program of China(Grant No.2013CBA01504)the National Natural Science Foundation of China(Grant Nos.11421064,11129503,11374209,and 11374210)
文摘With the advent of ultrashort high intensity laser pulses, laser absorption during the laser–solid interactions has received significant attention over the last two decades since it is related to a variety of applications of high intensity lasers,including the hot electron production for fast ignition of fusion targets, table-top bright X-ray and gamma-ray sources,ion acceleration, compact neutron sources, and generally the creation of high energy density matters. Normally, some absorption mechanisms found for nanosecond long laser pulses also appear for ultrashort laser pulses. The peculiar aspects with ultrashort laser pulses are that their absorption depends significantly on the preplasma condition and the initial target structures. Meanwhile, relativistic nonlinearity and ponderomotive force associated with the laser pulses lead to new mechanisms or phenomena, which are usually not found with nanosecond long pulses. In this paper, we present an overview of the recent progress on the major absorption mechanisms in intense laser–solid interactions, where emphasis is paid to our related theory and simulation studies.
基金National Natural Science Foundations of China(No.50803010,No.60904056)
文摘This paper is devoted to the two-dimensional nonlinear modeling of the fluid-solid interaction (FSI) between fabric and air flow, which is based on the Automatic Incremental Dynamic Nonlinear Analysis (AIDNA)-FSI program in order to study the dynamic bending features of fabrics in a specific air flow filed. The computational fluid dynamics (CFD) model for flow and the finite element model (FEM) for fabric was set up to constitute an FSI model in which the geometric nonlinear behavior and the dynamic stress-strain variation of the relatively soft fabric material were taken into account. Several FSI cases with different time-dependent wind load and the model frequency analysis for fabric were carried out. The dynamic response of fabric and the distribution of fluid variables were investigated. The results of numerical simulation and experiments fit quite well. Hence, this work contributes to the research of modeling the dynamic bending behavior of fabrics in air field.
基金The work is supported by the US National Science Foundation(NSF)through the research grant DMS-1522554We thank the unknown Reviewers for their helpful suggestions and comments which have helped us.
文摘Problems involving fluid flexible-structure interactions(FFSI)are ubiquitous in engineering and sciences.Peskin’s immersed boundary(IB)method is the first framework for modeling and simulation of such problems.This paper addresses a three-dimensional extension of the IB framework for non-Newtonian fluids which include power-law fluid,Oldroyd-B fluid,and FENE-P fluid.The motion of the non-Newtonian fluids are modelled by the lattice Boltzmann equations(D3Q19 model).The differential constitutive equations of Oldroyd-B and FENE-P fluids are solved by the D3Q7 model.Numerical results indicate that the new method is first-order accurate and conditionally stable.To show the capability of the new method,it is tested on three FFSI toy problems:a power-law fluid past a flexible sheet fixed at its midline,a flexible sheet being flapped periodically at its midline in an Oldroyd-B fluid,and a flexible sheet being rotated at one edge in a FENE-P fluid.
基金support from the National Natural Science Foundation of China(Nos.52120105007,51834010)the National Science Fund for Distinguished Young Scholars(No.52222403).
文摘Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.
基金the National Natural Science Foundation of China (11202215 and 11332011)the Youth Innovation Promotion Association of CAS (2015015)
文摘Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for numerical simulation based on computational fluid dynamics and nonlinear finite element analysis methods. The typical results of the numerical simulation and wind tunnel experiment, including the overall lift and deformation, are in good agreement with each other. The results obtained indicate that the effect of fluid-structure interaction is noticeable and should be considered for non-rigid airships. Flow- induced deformation can further intensify the upward lift force and pitching moment, which can lead to a large deformation. Under a wind speed of 15 m/s, the lift force of the non-rigid model is increased to approximatelv 60% compared with that of the rigid model under a high angle of attack.
基金supported by the National Natural Science Foundation of China(Nos.52574471,52404423,and 52334009)the Open Research Fund of Songshan Lake Materials Laboratory(No.2023SLABFK12)the Science and Technology Commission of Shanghai Municipality(Nos.23ZR1421600,21DZ1208900,and 19DZ2270200).
文摘Composite solid-state electrolytes(CSEs)have garnered significant attention for nextgeneration energy storage owing to their inherent safety features compared with those of their liquid counterparts.However,their practical deployment remains hindered by sluggish lithium-ion transport kinetics and interfacial instability.Herein,we introduced a bimetal oxide enhanced strategy for oxygen-vacancy-engineered double perovskite nanofillers(PrBaCoFeO_(5+δ)(PBCF))to address these challenges in polyethylene oxide(PEO)-based CSEs.The strong Lewis acid-base coordination between Co^(3+)/Fe^(3+)sites on PBCF and ether oxygen groups in PEO effectively suppresses the polymer-chain crystallization while creating continuous Li^(+)conduction pathways.Importantly,the abundant oxygen vacancies serve as catalytic centers to decompose lithium bis(trifluoromethanesulfonyl)imide(LiTFSI),thereby forming a robust organic-inorganic hybrid solid electrolyte interphase(SEI).Consequently,the prepared PEO-LiTFSI-PBCF CSE achieves an improved Li^(+)ionic conductivity of 2.76×10^(-4) S·cm^(-1)(30℃)and an elevated Li^(+)transference number(0.54).The Li||Li symmetric cell exhibits impressive lithium plating/stripping ability(>6000 h at 0.1 mA·cm^(-2))and practical viability in Li||LiFePO_(4)full cells with 90.1% capacity retention after 500 cycles at 30℃(0.3 C).This defect engineering strategy provides new insights into the construction of fast and stable Li^(+)transport channels in polymer solid-state electrolytes,paving the way for high-energy-density all-solid-state lithium metal batteries.
文摘Fluid and solid simulation is to generate a realistic simulation of fluids and solids,in particular for the fluids such as water and smoke,with computation of Euler equations or Navier-Stokes equations conducted to govern the real fluid physics.Fluid simulation is an important field by its wide applications in many fields and industries,such as film and game simulation,weather forecasting,natural disaster simulation and protection,simulation in maritime and aviation.There are basically two main categories of methods for fluid simulation,data-driven methods and physically-based methods.The data-driven models establish a direct mapping between variables and extract their relationship from historically measured data by the algorithms developed in the fields of statistics,computational intelligence,machine learning,and data mining.
基金financial supports from the National Natural Science Foundation of China (Nos. 21373035, 21673027 and 21603022)the Fundamental Research Funds for the Central Universities in China (Nos. DUT16RC(3)002 and DUT17TD04)
文摘CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mechanical stabilities. Deep insights into the mechanism of stereocomplexation are of particular importance to the design and manufacture of new promising and sustainable polycarbonates with enhanced physicochemical properties. Our solid-state NMR experiments linking with DFT computations clearly reveal the specific chain-chain interactions in a typical stereocomplexed poly（4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0] octane carbonate）（PCXC）.13C CP/MAS NMR,1H DUMBO MAS NMR and 13C/1H relaxation-time measurements indicate that the formation of stereocomplex reduces the local mobilities of carbonyl, methine and methylene groups in each chain of PCXC significantly. Through a combination of two-dimensional 1H-13C HETCOR NMR and DFT calculation analysis, the cis-/trans-conformations and packing models of PCXC chains in the amorphous, enantionpure isotactic and stereocomplexed polycarbonates are identified. The splitting of 13C and 1H NMR chemical shifts of methine groups in the backbone carbon region demonstrates the ordered interlock interactions between the R-and S-chain in the stereocomplexed PCXC.
