The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of var...The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of varied pre-aging states of NiTi particles into the 5052Al matrix using a rolling composite technique.The aim is to enhance the application scope of aluminum alloy for vibration and noise reduction.The results demonstrated a distinct and integrated interface between the particle layer and the 5052Al alloy,with numerous interparticle interfaces within the particle layer.Increasing the aging temperature of the NiTi particles from 450 to 550℃ shifted the phase transition peaks of the composites to lower temperatures.The damping capacity of the laminated NiTip/5052Al composites notably surpasses that of the 5052Al alloy.At 28 and 66℃,the phase transformation damping peaks of the pre-aged NiTi particle layer reinforced 5052Al matrix composites are 1.93 and 2 times those of the 5052Al alloy at the corresponding temperatures,respectively.The collaborative impact of interparticle interface damping mechanism and the phase transformation damping mechanism of NiTi-reinforced particles significantly amplify the low-temperature damping performance of the laminated NiTip/5052Al composites.展开更多
The thermal flux curve of phase-transition fluid(PF)was tested using differential scanning calorimetry,based on which a reaction kinetics model was established to reflect the relationship between phase transition conv...The thermal flux curve of phase-transition fluid(PF)was tested using differential scanning calorimetry,based on which a reaction kinetics model was established to reflect the relationship between phase transition conversion rate,temperature and time.A temperature field model for fractures and rock matrix considering phase transition heat was then constructed,and its reliability was verified using previously established temperature field models.Additionally,the new model was used to study the effects of different injection parameters and phase-transition fracturing performance parameters on the temperature variations in fractures and matrix.The study indicates that,at different positions and times,the cooling effect of the injected cold fluid and the exothermic effect during the phase transition alternately dominate the temperature within the fracture.At the initial stage of fracturing fluid injection,the temperature within the fracture is high,and the phase transition rate is rapid,resulting in a significant impact of exothermic phase transition on the reservoir rock temperature.In the later stage of injection,the fracture temperature decreases,the phase transition exothermic rate slows,and the cooling effect of the fracturing fluid on the reservoir rock intensifies.Phase transition heat significantly affects the temperature of the fracture.Compared to cases where phase transition heat is not considered,when it is taken into account,the temperature within the fracture increases to varying degrees at the end of fluid injection.As the phase transition heat increases from 20 J/g to 60 J/g,the maximum temperature rise in the fracture increases from 2.1℃ to 6.2℃.The phase transition heat and PF volume fraction are positively correlated with fracture temperature changes,while specific heat capacity is negatively correlated with temperature changes.With increasing injection time,the temperature and phase transition rate at the fracture opening gradually decrease,and the location of the maximum phase transition rate and temperature difference gradually shifts from the fracture opening to about 10 m from the opening.展开更多
The general use of aluminium as an indentation standard for the iteration of contact heights for the determination of ISO-14577 hardness and elastic modulus is challenged because of as yet not appreciated phase-change...The general use of aluminium as an indentation standard for the iteration of contact heights for the determination of ISO-14577 hardness and elastic modulus is challenged because of as yet not appreciated phase-changes in the physical force-depth standard curve that seemed to be secured by claims from 1992. The physical and mathematical analyses with closed formulas avoid the still world-wide standardized energy-law violation by not reserving 33.33% (h2 belief) (or 20% h3/2 physical law) of the loading force and thus energy for all not depth producing events but using 100% for the depth formation is a severe violation of the energy law. The not depth producing part of the indentation work cannot be done with zero energy! Both twinning and structural phase-transition onsets and normalized phase-transition energies are now calculated without iterations but with physically correct closed arithmetic equations. These are reported for Berkovich and cubecorner indentations, including their comparison on geometric grounds and an indentation standard without mechanical twinning is proposed. Characteristic data are reported. This is the first detection of the indentation twinning of aluminium at room temperature and the mechanical twinning of fused quartz is also new. Their disqualification as indentation standards is established. Also, the again found higher load phase-transitions disqualify aluminium and fused quartz as ISO-ASTM 14577 (International Standardization Organization and American Society for Testing and Materials) standards for the contact depth “hc” iterations. The incorrect and still world-wide used black-box values for H- and Er-values (the latter are still falsely called “Young’s moduli” even though they are not directional) and all mechanical properties that depend on them. They lack relation to bulk moduli from compression experiments. Experimentally obtained and so published force vs depth parabolas always follow the linear FN = kh3/2 + Fa equation, where Fa is the axis-cut before and after the phase-transition branches (never “h2” as falsely enforced and used for H, Er and giving incorrectly calculated parameters). The regression slopes k are the precise physical hardness values, which for the first time allow for precise calculation of the mechanical qualities by indentation in relation to the geometry of the indenter tip. Exactly 20% of the applied force and thus energy is not available for the indentation depth. Only these scientific k-values must be used for AI-advises at the expense of falsely iterated indentation hardness H-values. Any incorrect H-ISO-ASTM and also the iterated Er-ISO-ASTM modulus values of technical materials in artificial intelligence will be a disaster for the daily safety. The AI must be told that these are unscientific and must therefore be replaced by physical data. Iterated data (3 and 8 free parameters!) cannot be transformed into physical data. One has to start with real experimental loading curves and an absolute ZerodurR standard that must be calibrated with standard force and standard length to create absolute indentation results. .展开更多
Bacterial cellulose(BC)is one of the most versatile natural biopolymers with unique physical,chemical,and biological features.However,the lack of intrinsic antibacterial property of native BC limits its broad biomedic...Bacterial cellulose(BC)is one of the most versatile natural biopolymers with unique physical,chemical,and biological features.However,the lack of intrinsic antibacterial property of native BC limits its broad biomedical applications where such property is highly required to prevent contamination or infection caused by attached bacteria.In this work,we developed a simple and facile method to fabricate a dualfunctional BC membrane by physical incorporation of gold nanorods(GNRs)followed by deposition of a phase-transitioned bovine serum albumin(PTB)film.Due to the broad-spectrum antifouling property of the PTB film,the resulting membrane could prevent the adhesion and accumulation of bacteria.A few bacteria that broke through the protection of the PTB film could be eradicated under short-term irradiation of a near-infrared laser due to the excellent photothermal property of incorporated GNRs.The whole fabrication was conducted in a simple and environmentally friendly manner,avoiding complicated processes and toxic organic solvents.Moreover,because all the components were biocompatible,the resulting membrane showed negligible cytotoxicity in vitro and good histocompatibility in vivo.This work thus provided a reliable way to endow BC with antibacterial property,being beneficial for diverse biomedical applications.展开更多
-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sa...-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sacrosanct simplest calculation rules for the loading parabola (now FN = kh3/2) giving straight lines for cones, pyramids and wedges. They provide the physical penetration resistance hardness k with dimension [Nm-3/2] and allow for non-iterative calculations with closed formulas, using simple undeniable calculation rules. The physically correct FN versus h3/2 plot is universally valid. It separates out the most common surface effects and reveals gradients. It provides unmatched precision, including reliability checks of experimental data. Regression analysis of FN versus h3/2 plots reveals eventual unsteadiness kink phase-transition onset with the transition-energy. This is shown for all kinds of solid materials, including salts, silicon, organics, polymers, composites, and superalloys. Exothermic and endothermic single and consecutive multiple phase-transitions with their surface dependence are distinguished and the results compared in 5 Tables. The sharp phase-transition onsets and the transition energies provide unprecedented most important materials’ characteristics that are indispensable for safety reasons. ISO ASTM is thus urged to thoroughly revise ISO 14577 and to work out new standards for the mechanically (also thermally) stressed materials. For example, the constancy of the first phase-transition parameters must be controlled, and materials must only be admitted for maximal forces well below the first phase-transition onset. Such onset loads can now be easily calculated. The nevertheless repeated oppositions against the physical analysis of indentations rest on incredibly poor knowledge of basic mathematics, errors that are uncovered. The safety aspects caused by the present unphysical materials’ parameters are discussed.展开更多
A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambi- ent air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide （SO3）, water ...A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambi- ent air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide （SO3）, water with dissolved salts, and particles in the wet flue gas form secondary pollution in the surrounding atmosphere. In this study, a deep purification technology for flue gas involving phase-transition agglom- eration and dehumidification （PAD） is proposed. This deep purification technology includes two technical routes： the integrated technology of phase-transition agglomeration and a wet electrostatic precipitator （PAW）; and the integrated technology of phase-transition agglomeration and a mist eliminator （PAM）. Industrial applications of PAW and PAM were carried out on 630 and 1000 MW coal-fired units, respectively. The results show that the average amount of recycled water obtained from wet flue gas by means of PAD is more than 4 g.（kg.℃）-1 Decreasing the wet flue gas temperature by 1.5-5.3 ℃ allows 5%-20% of the moisture in the flue gas to be recycled; therefore, this process could effectively save water resources and significantly reduce water vapor emissions. In addition, the moist plume is effectively elim- inated. With the use of this process, the ion concentration in droplets of flue gas is decreased by more than 65%, the SO3 removal efficiency from flue gas is greater than 75%, and the removal efficiency of par- ticulate matter is 92.53%.展开更多
The structures,grain sizes and magnetism were analyzed and computed for three typical samples:the stock of polycrystalline metal Gd(sample 1),the bulk nanocrystalline Gd prepared by spark plasma sintering(SPS) techniq...The structures,grain sizes and magnetism were analyzed and computed for three typical samples:the stock of polycrystalline metal Gd(sample 1),the bulk nanocrystalline Gd prepared by spark plasma sintering(SPS) technique and subjected to the annealing process of 623 K for 0.5 h(sample 2) and the bulk nanocrystalline Gd prepared by the SPS technique at 573 K(sample 3).The computation results indicated that the sample 3 had the efficiency of space filling up to 99.38%.The computation results of magnetization i...展开更多
The QCD deconfinement phase transition in pure SU（3） gauge theory is studied on an anlsotropic lattice. The critical temperature is determined to be Tc ≈ 285 MeV. The relation between the deconfinement phase transi...The QCD deconfinement phase transition in pure SU（3） gauge theory is studied on an anlsotropic lattice. The critical temperature is determined to be Tc ≈ 285 MeV. The relation between the deconfinement phase transition and the breakdown of Z（3） center symmetry is also discussed.展开更多
The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionall...The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionally, given an arbitrary non-Hermitian PT-symmetric Hamiltonian, one has to solve the corresponding Schrodinger equation explicitly in order to determine which phase it is actually in. Here, we propose to use artificial neural network(ANN) to determine the PT-phase-transition points for non-Hermitian PT-symmetric systems with short-range potentials. The numerical results given by ANN agree well with the literature, which shows the reliability of our new method.展开更多
The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensat...The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores.展开更多
The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of applications.To effectively utilize THz radiation,modulators with precise control are i...The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of applications.To effectively utilize THz radiation,modulators with precise control are imperative.While most recent THz modulators manipulate the amplitude,frequency,or phase of incident THz radiation,considerably less progress has been made toward THz polarization modulation.Conventional methods for polarization control suffer from high driving voltages,restricted modulation depth,and narrow band capabilities,which hinder device performance and broader applications.Consequently,an ideal THz modulator that offers high modulation depth along with ease of processing and operation is required.In this paper,we propose and realize a THz metamaterial comprised of microelectromechanical systems(MEMS)actuated by the phase-transition material vanadium dioxide(VO_(2)).Simulation and experimental results of the three-dimensional metamaterials show that by leveraging the unique phase-transition attributes of VO_(2),our THz polarization modulator offers notable advancements over existing designs,including broad operation spectrum,high modulation depth,ease of fabrication,ease of operation condition,and continuous modulation capabilities.These enhanced features make the system a viable candidate for a range of THz applications,including telecommunications,imaging,and radar systems.展开更多
Electrochemistry with antifouling sensing interfaces that effectively resist the adsorption of nonspecific biomolecules provides a powerful mean for the accurate and sensitive detection of disease biomarkers tive dete...Electrochemistry with antifouling sensing interfaces that effectively resist the adsorption of nonspecific biomolecules provides a powerful mean for the accurate and sensitive detection of disease biomarkers tive dete in complex biofluids.However.there are few strategies to acquire a stable and solid antifouling coat-ing on any substrate by a simple way.Herein,a simple one-step assembly methød has been adopted to construct phase-transited bovine serum albumin(PTB)antifouling Layers.Prior to construction of the an-tifouling layers.the poly(3,4-ethylenedioxythiophene)(PEDOT)doped with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(ionic liquid,IL)were firstly electrodeposited on bare electrodes,en-dowing good conductiviry and catalytic capability for the developed sensor.Subsequently.with the assist of tris(2-carboxyethyl)phosphine(TCEP)the disulfide bonds of bovine serum albumin(BSA)were re-Im alb duced to form PTB,which can be coated on the PEDOT-It modified electrode to construct an antifouling electrochemical senor(PTB/PEDOT-ILCCE)for the detection of uric acid(UA)in human serum.The UA sensor demonstrated a good linear range from 1.11 umol/L to 798.9 umol/L with a high sensltivity of0,556 jA umolL^(-1)cm^(-2).The combination of conducting polymers with one-step assembly of PTB offers a universal and rellable method før the modification of various electrodes to determine target molecules in complex human body fluids.展开更多
The transformation of Li_(2)S_(2)-Li_(2)S is indubitably the most crucial and labored rate-limiting step among the sophisticated reactions for the lithium-sulfur batteries(LSBs),the adjustment of which is anticipated ...The transformation of Li_(2)S_(2)-Li_(2)S is indubitably the most crucial and labored rate-limiting step among the sophisticated reactions for the lithium-sulfur batteries(LSBs),the adjustment of which is anticipated to impede the shuttle effect.Herein,a N,Se dual-doped carbon nanocages embedded by Co-CoSe_(2)nanoparticles(Co-CoSe_(2)@NSeC)is employed as a functional coating layer on commercial separator to improve the performance of LSBs.The well-designed N,Se co-doped nanostructures endow the modified layer with a satisfactory capacity for blocking polysulfides.Both calculations and experiments jointly disclose that the Li_(2)S_(2)to Li_(2)S reaction,including the liquid-solid conversion,was prominently expedited both thermodynamically and electrodynamically.Consequently,the batteries fabricated with Co-CoSe_(2)@NSeC modified separator can deliver a favorable 764.2 mAh g^(−1)with 8.0 C,accompanied by a salient long cycling lifespan(only 0.066%at 1 C and 0.061%under 2 C after 1000 and 2000 cycles),and a desired anode protection.In addition,despite a raised areal loading of 7.53 mg cm^(−2)was introduced,the cells assembled by Co-CoSe_(2)@NSeC@PP are allowed to produce an outstanding initial behavior of 8.71 mAh cm^(−2)under 0.2 C.This work may reinforce further explorations and serve with valuable insights into N,Se dual-doping materials for high-performance LSBs.展开更多
A continuum opinion dynamic model is presented based on two rules. The first one considers the mobilities of the individuals, the second one supposes that the individuals update their opinions independently. The resul...A continuum opinion dynamic model is presented based on two rules. The first one considers the mobilities of the individuals, the second one supposes that the individuals update their opinions independently. The results of the model indicate that the bounded confidence εc, separating consensus and incoherent states, of a scale-free network is much smaller than the one of a lattice. If the system can reach the consensus state, the sum of all individuals＇ opinion change Oc（t） quickly decreases in an exponential form, while if it reaches the incoherent state finally, Oc（t） decreases slowly and has the punctuated equilibrium characteristic.展开更多
This paper presents a cellular automaton model for single-lane traffic flow. On the basis of the Nagel-Schreckenberg （NS） model, it further considers the effect of headway-distance between two successive cars on the...This paper presents a cellular automaton model for single-lane traffic flow. On the basis of the Nagel-Schreckenberg （NS） model, it further considers the effect of headway-distance between two successive cars on the randomization of the latter one. In numerical simulations, this model shows the following characteristics. （1） With a simple structure, this model succeeds in reproducing the hysteresis effect, which is absent in the NS model. （2） Compared with the slow-tostart models, this model exhibits a local fundamental diagram which is more consistent to empirical observations. （3） This model has much higher efficiency in dissolving congestions compared with the so-called NS model with velocitydependent randomization （VDR model）. （4） This model is more robust when facing traffic obstructions. It can resist much longer shock times and has much shorter relaxation times on the other hand. To summarize, compared with the existing models, this model is quite simple in structure, but has good characteristics.展开更多
Temperature dependence of viscosity for more than ten kinds of metallic melts is analysed based on viscosity measurements. An obvious turning point is observed on the Arrhenius curves. Since viscosity is one of the ph...Temperature dependence of viscosity for more than ten kinds of metallic melts is analysed based on viscosity measurements. An obvious turning point is observed on the Arrhenius curves. Since viscosity is one of the physical properties sensitive to structure, its discontinuous change with temperature reveals the possible liquidliquid structure transition in the metallic melts. Furthermore, an integrated liquid structure transition diagram of the Sn-Bi system is presented. The universality of liquid-liquid structure transition is also discussed simply.展开更多
It is significant to numerically investigate thermo-mechanical behaviors of shape memory alloy(SMA)structures undergoing large and uneven deformation for they are used in many engineering fields to meet special requir...It is significant to numerically investigate thermo-mechanical behaviors of shape memory alloy(SMA)structures undergoing large and uneven deformation for they are used in many engineering fields to meet special requirements To solve the problems of convergence in the numerical simulation on thermo-mechanical behaviors of SMA structures by universal finite element software.This work suppose a finite element method to simulate the super-elasticity and shape memory effect in the SMA structure undergoing large and uneven deformation.Two scalars,named by phase-transition modulus and equivalent stiffness,are defined to make it easy to establish and implement the finite element method for a SMA structure.An incremental constitutive equation is developed to formulate the relationship of stress,strain and temperature in a SMA material based on phase-transition modulus and equivalent stiffness.A phase-transition modulus equation is derived to describe the relationship of phase-transition modulus,stress and temperature in a SMA material during the processes of martensitic phase transition and martensitic inverse phase transition.A finite element equation is established to express the incremental relationship of nodal displacement,external force and temperature change in a finite element discrete structure of SMA.The incremental constitutive equation,phase-transition modulus equation and finite element equation compose the supposed finite element method which simulate the thermo-mechanical behaviors of a SMA structure.Two SMA structures,which undergo large and uneven deformation,are numerically simulated by the supposed finite element method.Results of numerical simulation show that the supposed finite element method can effectively simulate the super-elasticity and shape memory effect of a SMA structure undergoing large and uneven deformation,and is suitable to act as an effective computational tool for the wide applications based on the SMA materials.展开更多
In order to exhibit the meta-stable states, several slow-to-start rules have been investigated as modification to Nagel-Schreckenberg （NS） model. These models can reproduce some realistic phenomena which are absent ...In order to exhibit the meta-stable states, several slow-to-start rules have been investigated as modification to Nagel-Schreckenberg （NS） model. These models can reproduce some realistic phenomena which are absent in the original NS model. But in these models, the size of cluster is still not considered as a useful parameter. In real traffic, the slow-to-start motion of a standing vehicle often depends on the degree of congestion which can be measured by the clusters＇ size. According to this idea, we propose a cluster-size dependent slow-to-start model based on the speed- dependent slow-to-start rule （VDR） model. It gives expected results through simulations. Comparing with the VDR model, our new model has a better traffic efficiency and shows richer complex characters.展开更多
The water gas shift （WGS） reaction is reacts with water on a catalytic surface a process of industrial importance to form CO2 and H2. We study this In this reaction carbon monoxide reaction with thermal （Langmuir- ...The water gas shift （WGS） reaction is reacts with water on a catalytic surface a process of industrial importance to form CO2 and H2. We study this In this reaction carbon monoxide reaction with thermal （Langmuir- Hinshelwood） and non-thermal （precursor and Eley-Rideal） reaction mechanisms using the techniques of Monte Carlo computer simulation. The details of surface coverages and production rates are given as a function of CO partial pressure. The diffusion of species on the surface as well as their desorption from the surface is also introduced to include temperature effects. The phase diagrams of the system have been drawn to observe the behaviour of reacting species on the surface. The study reveals that the production rates are higher for non-thermal precursor mechanism and are in agreement with the experimental finding.展开更多
Moessbauer studies on the effect of substitution with 3% Al, Co, Mn atoms in the intermetallic compound of Hf0.8Ta0.2Fe2 are reported. The Al substitution leads to increase of the FM-AFM transition temperature and to ...Moessbauer studies on the effect of substitution with 3% Al, Co, Mn atoms in the intermetallic compound of Hf0.8Ta0.2Fe2 are reported. The Al substitution leads to increase of the FM-AFM transition temperature and to decrease of the AFM-PM transition temperature. The Co substitution leads to disappearance of the FM state, only showing some FM impurity component, while Mn substituted compound indicates coexistence of FM and AFM states at low temperature. The phenomena imply complex itinerant electron properties in these magnetic systems.展开更多
基金National Natural Science Foundation of China (No. 52061011)Guangxi Natural Science Foundation,China (No. 2022GXNSFAA035574)Innovation Project of Guangxi Graduate Education,China (No. YCSW2023361)。
文摘The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of varied pre-aging states of NiTi particles into the 5052Al matrix using a rolling composite technique.The aim is to enhance the application scope of aluminum alloy for vibration and noise reduction.The results demonstrated a distinct and integrated interface between the particle layer and the 5052Al alloy,with numerous interparticle interfaces within the particle layer.Increasing the aging temperature of the NiTi particles from 450 to 550℃ shifted the phase transition peaks of the composites to lower temperatures.The damping capacity of the laminated NiTip/5052Al composites notably surpasses that of the 5052Al alloy.At 28 and 66℃,the phase transformation damping peaks of the pre-aged NiTi particle layer reinforced 5052Al matrix composites are 1.93 and 2 times those of the 5052Al alloy at the corresponding temperatures,respectively.The collaborative impact of interparticle interface damping mechanism and the phase transformation damping mechanism of NiTi-reinforced particles significantly amplify the low-temperature damping performance of the laminated NiTip/5052Al composites.
基金Supported by the China Postdoctoral Science Foundation(2024M752803)the Open Fund of Key Laboratory of Deep Geothermal Resources of Ministry of Natural Resources(KLDGR2024B01)+1 种基金the National Natural Science Foundation of China(52179112)the Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)(PLN2023-02)。
文摘The thermal flux curve of phase-transition fluid(PF)was tested using differential scanning calorimetry,based on which a reaction kinetics model was established to reflect the relationship between phase transition conversion rate,temperature and time.A temperature field model for fractures and rock matrix considering phase transition heat was then constructed,and its reliability was verified using previously established temperature field models.Additionally,the new model was used to study the effects of different injection parameters and phase-transition fracturing performance parameters on the temperature variations in fractures and matrix.The study indicates that,at different positions and times,the cooling effect of the injected cold fluid and the exothermic effect during the phase transition alternately dominate the temperature within the fracture.At the initial stage of fracturing fluid injection,the temperature within the fracture is high,and the phase transition rate is rapid,resulting in a significant impact of exothermic phase transition on the reservoir rock temperature.In the later stage of injection,the fracture temperature decreases,the phase transition exothermic rate slows,and the cooling effect of the fracturing fluid on the reservoir rock intensifies.Phase transition heat significantly affects the temperature of the fracture.Compared to cases where phase transition heat is not considered,when it is taken into account,the temperature within the fracture increases to varying degrees at the end of fluid injection.As the phase transition heat increases from 20 J/g to 60 J/g,the maximum temperature rise in the fracture increases from 2.1℃ to 6.2℃.The phase transition heat and PF volume fraction are positively correlated with fracture temperature changes,while specific heat capacity is negatively correlated with temperature changes.With increasing injection time,the temperature and phase transition rate at the fracture opening gradually decrease,and the location of the maximum phase transition rate and temperature difference gradually shifts from the fracture opening to about 10 m from the opening.
文摘The general use of aluminium as an indentation standard for the iteration of contact heights for the determination of ISO-14577 hardness and elastic modulus is challenged because of as yet not appreciated phase-changes in the physical force-depth standard curve that seemed to be secured by claims from 1992. The physical and mathematical analyses with closed formulas avoid the still world-wide standardized energy-law violation by not reserving 33.33% (h2 belief) (or 20% h3/2 physical law) of the loading force and thus energy for all not depth producing events but using 100% for the depth formation is a severe violation of the energy law. The not depth producing part of the indentation work cannot be done with zero energy! Both twinning and structural phase-transition onsets and normalized phase-transition energies are now calculated without iterations but with physically correct closed arithmetic equations. These are reported for Berkovich and cubecorner indentations, including their comparison on geometric grounds and an indentation standard without mechanical twinning is proposed. Characteristic data are reported. This is the first detection of the indentation twinning of aluminium at room temperature and the mechanical twinning of fused quartz is also new. Their disqualification as indentation standards is established. Also, the again found higher load phase-transitions disqualify aluminium and fused quartz as ISO-ASTM 14577 (International Standardization Organization and American Society for Testing and Materials) standards for the contact depth “hc” iterations. The incorrect and still world-wide used black-box values for H- and Er-values (the latter are still falsely called “Young’s moduli” even though they are not directional) and all mechanical properties that depend on them. They lack relation to bulk moduli from compression experiments. Experimentally obtained and so published force vs depth parabolas always follow the linear FN = kh3/2 + Fa equation, where Fa is the axis-cut before and after the phase-transition branches (never “h2” as falsely enforced and used for H, Er and giving incorrectly calculated parameters). The regression slopes k are the precise physical hardness values, which for the first time allow for precise calculation of the mechanical qualities by indentation in relation to the geometry of the indenter tip. Exactly 20% of the applied force and thus energy is not available for the indentation depth. Only these scientific k-values must be used for AI-advises at the expense of falsely iterated indentation hardness H-values. Any incorrect H-ISO-ASTM and also the iterated Er-ISO-ASTM modulus values of technical materials in artificial intelligence will be a disaster for the daily safety. The AI must be told that these are unscientific and must therefore be replaced by physical data. Iterated data (3 and 8 free parameters!) cannot be transformed into physical data. One has to start with real experimental loading curves and an absolute ZerodurR standard that must be calibrated with standard force and standard length to create absolute indentation results. .
基金financially supported by the National Natural Science Foundation of China(Nos.21774086 and 22175125)the Natural Science Foundation of Jiangsu Province(No.BK20180093)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.21KJA150008)the Suzhou Municipal Science and Technology Foundation(No.SYS2018026)。
文摘Bacterial cellulose(BC)is one of the most versatile natural biopolymers with unique physical,chemical,and biological features.However,the lack of intrinsic antibacterial property of native BC limits its broad biomedical applications where such property is highly required to prevent contamination or infection caused by attached bacteria.In this work,we developed a simple and facile method to fabricate a dualfunctional BC membrane by physical incorporation of gold nanorods(GNRs)followed by deposition of a phase-transitioned bovine serum albumin(PTB)film.Due to the broad-spectrum antifouling property of the PTB film,the resulting membrane could prevent the adhesion and accumulation of bacteria.A few bacteria that broke through the protection of the PTB film could be eradicated under short-term irradiation of a near-infrared laser due to the excellent photothermal property of incorporated GNRs.The whole fabrication was conducted in a simple and environmentally friendly manner,avoiding complicated processes and toxic organic solvents.Moreover,because all the components were biocompatible,the resulting membrane showed negligible cytotoxicity in vitro and good histocompatibility in vivo.This work thus provided a reliable way to endow BC with antibacterial property,being beneficial for diverse biomedical applications.
文摘-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sacrosanct simplest calculation rules for the loading parabola (now FN = kh3/2) giving straight lines for cones, pyramids and wedges. They provide the physical penetration resistance hardness k with dimension [Nm-3/2] and allow for non-iterative calculations with closed formulas, using simple undeniable calculation rules. The physically correct FN versus h3/2 plot is universally valid. It separates out the most common surface effects and reveals gradients. It provides unmatched precision, including reliability checks of experimental data. Regression analysis of FN versus h3/2 plots reveals eventual unsteadiness kink phase-transition onset with the transition-energy. This is shown for all kinds of solid materials, including salts, silicon, organics, polymers, composites, and superalloys. Exothermic and endothermic single and consecutive multiple phase-transitions with their surface dependence are distinguished and the results compared in 5 Tables. The sharp phase-transition onsets and the transition energies provide unprecedented most important materials’ characteristics that are indispensable for safety reasons. ISO ASTM is thus urged to thoroughly revise ISO 14577 and to work out new standards for the mechanically (also thermally) stressed materials. For example, the constancy of the first phase-transition parameters must be controlled, and materials must only be admitted for maximal forces well below the first phase-transition onset. Such onset loads can now be easily calculated. The nevertheless repeated oppositions against the physical analysis of indentations rest on incredibly poor knowledge of basic mathematics, errors that are uncovered. The safety aspects caused by the present unphysical materials’ parameters are discussed.
文摘A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambi- ent air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide （SO3）, water with dissolved salts, and particles in the wet flue gas form secondary pollution in the surrounding atmosphere. In this study, a deep purification technology for flue gas involving phase-transition agglom- eration and dehumidification （PAD） is proposed. This deep purification technology includes two technical routes： the integrated technology of phase-transition agglomeration and a wet electrostatic precipitator （PAW）; and the integrated technology of phase-transition agglomeration and a mist eliminator （PAM）. Industrial applications of PAW and PAM were carried out on 630 and 1000 MW coal-fired units, respectively. The results show that the average amount of recycled water obtained from wet flue gas by means of PAD is more than 4 g.（kg.℃）-1 Decreasing the wet flue gas temperature by 1.5-5.3 ℃ allows 5%-20% of the moisture in the flue gas to be recycled; therefore, this process could effectively save water resources and significantly reduce water vapor emissions. In addition, the moist plume is effectively elim- inated. With the use of this process, the ion concentration in droplets of flue gas is decreased by more than 65%, the SO3 removal efficiency from flue gas is greater than 75%, and the removal efficiency of par- ticulate matter is 92.53%.
基金supported by the National Basic Research Program of China (2006CB705601)the National Natural Science Foundation of China (50771002)
文摘The structures,grain sizes and magnetism were analyzed and computed for three typical samples:the stock of polycrystalline metal Gd(sample 1),the bulk nanocrystalline Gd prepared by spark plasma sintering(SPS) technique and subjected to the annealing process of 623 K for 0.5 h(sample 2) and the bulk nanocrystalline Gd prepared by the SPS technique at 573 K(sample 3).The computation results indicated that the sample 3 had the efficiency of space filling up to 99.38%.The computation results of magnetization i...
基金Supported by NSFC under Grant Nos.10347110,10575107,10421003,10835002CAS under Grant No.KJCX3-SYW-N2the Numerical Calculations were Performed on DeepComp 6800 Supercomputer of the Supercomputing Center of Chinese Academy of Sciences,Dawning 4000A Supercomputer of Shanghai Supercomputing Center,and NKstar 2 Supercomputer of Nankai University
文摘The QCD deconfinement phase transition in pure SU（3） gauge theory is studied on an anlsotropic lattice. The critical temperature is determined to be Tc ≈ 285 MeV. The relation between the deconfinement phase transition and the breakdown of Z（3） center symmetry is also discussed.
基金Supported by the National Natural Science Foundation of China (Grant Nos.11535004,11975167,11761161001,11375086,11565010,11881240623 and 11961141003)the National Key R&D Program of China (Grant Nos.2018YFA0404403 and 2016YFE0129300)+1 种基金the Science and Technology Development Fund of Macao (Grant No.008/2017/AFJ)the Fundamental Research Funds for the Central Universities (Grant Nos.22120210138 and 22120200101)。
文摘The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionally, given an arbitrary non-Hermitian PT-symmetric Hamiltonian, one has to solve the corresponding Schrodinger equation explicitly in order to determine which phase it is actually in. Here, we propose to use artificial neural network(ANN) to determine the PT-phase-transition points for non-Hermitian PT-symmetric systems with short-range potentials. The numerical results given by ANN agree well with the literature, which shows the reliability of our new method.
基金the National Science Foundation of China (NSFC) the China Petrochemical Corporation (SINOPEC) (No. 29792077).
文摘The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores.
基金supported by NSF through the University of Delaware Materials Research Science and Engineering Center DMR-2011824.
文摘The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of applications.To effectively utilize THz radiation,modulators with precise control are imperative.While most recent THz modulators manipulate the amplitude,frequency,or phase of incident THz radiation,considerably less progress has been made toward THz polarization modulation.Conventional methods for polarization control suffer from high driving voltages,restricted modulation depth,and narrow band capabilities,which hinder device performance and broader applications.Consequently,an ideal THz modulator that offers high modulation depth along with ease of processing and operation is required.In this paper,we propose and realize a THz metamaterial comprised of microelectromechanical systems(MEMS)actuated by the phase-transition material vanadium dioxide(VO_(2)).Simulation and experimental results of the three-dimensional metamaterials show that by leveraging the unique phase-transition attributes of VO_(2),our THz polarization modulator offers notable advancements over existing designs,including broad operation spectrum,high modulation depth,ease of fabrication,ease of operation condition,and continuous modulation capabilities.These enhanced features make the system a viable candidate for a range of THz applications,including telecommunications,imaging,and radar systems.
基金supported by the China Postdoctoral Science Foundation(No.2022M711745)the Science and Technology Benefiting the People Project of Qingdao(No.20-3-4-53-nsh)the Taishan Scholar Program of Shandong Province of China(No.ts20110829).
文摘Electrochemistry with antifouling sensing interfaces that effectively resist the adsorption of nonspecific biomolecules provides a powerful mean for the accurate and sensitive detection of disease biomarkers tive dete in complex biofluids.However.there are few strategies to acquire a stable and solid antifouling coat-ing on any substrate by a simple way.Herein,a simple one-step assembly methød has been adopted to construct phase-transited bovine serum albumin(PTB)antifouling Layers.Prior to construction of the an-tifouling layers.the poly(3,4-ethylenedioxythiophene)(PEDOT)doped with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(ionic liquid,IL)were firstly electrodeposited on bare electrodes,en-dowing good conductiviry and catalytic capability for the developed sensor.Subsequently.with the assist of tris(2-carboxyethyl)phosphine(TCEP)the disulfide bonds of bovine serum albumin(BSA)were re-Im alb duced to form PTB,which can be coated on the PEDOT-It modified electrode to construct an antifouling electrochemical senor(PTB/PEDOT-ILCCE)for the detection of uric acid(UA)in human serum.The UA sensor demonstrated a good linear range from 1.11 umol/L to 798.9 umol/L with a high sensltivity of0,556 jA umolL^(-1)cm^(-2).The combination of conducting polymers with one-step assembly of PTB offers a universal and rellable method før the modification of various electrodes to determine target molecules in complex human body fluids.
基金supported by the National Natural Science Foundation of China(No.21875039)the Project on the Integration of Industry-Education-Research of Fujian Province(No.2021H6020).
文摘The transformation of Li_(2)S_(2)-Li_(2)S is indubitably the most crucial and labored rate-limiting step among the sophisticated reactions for the lithium-sulfur batteries(LSBs),the adjustment of which is anticipated to impede the shuttle effect.Herein,a N,Se dual-doped carbon nanocages embedded by Co-CoSe_(2)nanoparticles(Co-CoSe_(2)@NSeC)is employed as a functional coating layer on commercial separator to improve the performance of LSBs.The well-designed N,Se co-doped nanostructures endow the modified layer with a satisfactory capacity for blocking polysulfides.Both calculations and experiments jointly disclose that the Li_(2)S_(2)to Li_(2)S reaction,including the liquid-solid conversion,was prominently expedited both thermodynamically and electrodynamically.Consequently,the batteries fabricated with Co-CoSe_(2)@NSeC modified separator can deliver a favorable 764.2 mAh g^(−1)with 8.0 C,accompanied by a salient long cycling lifespan(only 0.066%at 1 C and 0.061%under 2 C after 1000 and 2000 cycles),and a desired anode protection.In addition,despite a raised areal loading of 7.53 mg cm^(−2)was introduced,the cells assembled by Co-CoSe_(2)@NSeC@PP are allowed to produce an outstanding initial behavior of 8.71 mAh cm^(−2)under 0.2 C.This work may reinforce further explorations and serve with valuable insights into N,Se dual-doping materials for high-performance LSBs.
基金Supported by the National Basic Research Programme of China under Grant No 2006CB705500, the National Natural Science Foundation of China under Grant Nos 10635040, 10532060, 70571074 and 10472116, the Special Research Funds for Theoretical Physics Frontier Problems （A0524701）, the President Fund of Chinese Academy of Sciences, the Specialized Research Fund for the Doctoral Programme of Higher Education of China, and the Research Fund of the Education Department of Liaoning Province （20060140）. The authors thank Dr Ming Zhao for her comments and suggestions.
文摘A continuum opinion dynamic model is presented based on two rules. The first one considers the mobilities of the individuals, the second one supposes that the individuals update their opinions independently. The results of the model indicate that the bounded confidence εc, separating consensus and incoherent states, of a scale-free network is much smaller than the one of a lattice. If the system can reach the consensus state, the sum of all individuals＇ opinion change Oc（t） quickly decreases in an exponential form, while if it reaches the incoherent state finally, Oc（t） decreases slowly and has the punctuated equilibrium characteristic.
基金supported by the National Basic Research Program of China (973 Program No 2006CB705500)the National Natural Science Foundation of China (Grant Nos 10635040, 10532060, 10472116 and 70271070)+2 种基金the Special Research Funds for Theoretical Physics Frontier Problems (NSFC Nos 10547004 and A0524701)the President Funding of Chinese Academy of Sciencethe Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘This paper presents a cellular automaton model for single-lane traffic flow. On the basis of the Nagel-Schreckenberg （NS） model, it further considers the effect of headway-distance between two successive cars on the randomization of the latter one. In numerical simulations, this model shows the following characteristics. （1） With a simple structure, this model succeeds in reproducing the hysteresis effect, which is absent in the NS model. （2） Compared with the slow-tostart models, this model exhibits a local fundamental diagram which is more consistent to empirical observations. （3） This model has much higher efficiency in dissolving congestions compared with the so-called NS model with velocitydependent randomization （VDR model）. （4） This model is more robust when facing traffic obstructions. It can resist much longer shock times and has much shorter relaxation times on the other hand. To summarize, compared with the existing models, this model is quite simple in structure, but has good characteristics.
基金Supported by the National Science Foundation of China under Grant Nos 50231040 and 50301013.
文摘Temperature dependence of viscosity for more than ten kinds of metallic melts is analysed based on viscosity measurements. An obvious turning point is observed on the Arrhenius curves. Since viscosity is one of the physical properties sensitive to structure, its discontinuous change with temperature reveals the possible liquidliquid structure transition in the metallic melts. Furthermore, an integrated liquid structure transition diagram of the Sn-Bi system is presented. The universality of liquid-liquid structure transition is also discussed simply.
基金Supported by National Key Research and Development Program of China(Grant No.2017YFC0307604)the Talent Foundation of China University of Petroleum(Grant No.Y1215042)
文摘It is significant to numerically investigate thermo-mechanical behaviors of shape memory alloy(SMA)structures undergoing large and uneven deformation for they are used in many engineering fields to meet special requirements To solve the problems of convergence in the numerical simulation on thermo-mechanical behaviors of SMA structures by universal finite element software.This work suppose a finite element method to simulate the super-elasticity and shape memory effect in the SMA structure undergoing large and uneven deformation.Two scalars,named by phase-transition modulus and equivalent stiffness,are defined to make it easy to establish and implement the finite element method for a SMA structure.An incremental constitutive equation is developed to formulate the relationship of stress,strain and temperature in a SMA material based on phase-transition modulus and equivalent stiffness.A phase-transition modulus equation is derived to describe the relationship of phase-transition modulus,stress and temperature in a SMA material during the processes of martensitic phase transition and martensitic inverse phase transition.A finite element equation is established to express the incremental relationship of nodal displacement,external force and temperature change in a finite element discrete structure of SMA.The incremental constitutive equation,phase-transition modulus equation and finite element equation compose the supposed finite element method which simulate the thermo-mechanical behaviors of a SMA structure.Two SMA structures,which undergo large and uneven deformation,are numerically simulated by the supposed finite element method.Results of numerical simulation show that the supposed finite element method can effectively simulate the super-elasticity and shape memory effect of a SMA structure undergoing large and uneven deformation,and is suitable to act as an effective computational tool for the wide applications based on the SMA materials.
基金Project supported by the State Key Development Program for Basic Research of China （Grant No 2006CB705500）, the National Natural Science Foundation of China （Grant Nos 10472116, 10532060, and 70571074）, the Special Research Funds for Theoretical Physics Frontier Problems （Grant Nos 10547004 and A0524701）, the Presidential Foundation of the Chinese Academy of Sciences, and the Specialized Rescarch Fund for the Doctoral Program of High Education of China.
文摘In order to exhibit the meta-stable states, several slow-to-start rules have been investigated as modification to Nagel-Schreckenberg （NS） model. These models can reproduce some realistic phenomena which are absent in the original NS model. But in these models, the size of cluster is still not considered as a useful parameter. In real traffic, the slow-to-start motion of a standing vehicle often depends on the degree of congestion which can be measured by the clusters＇ size. According to this idea, we propose a cluster-size dependent slow-to-start model based on the speed- dependent slow-to-start rule （VDR） model. It gives expected results through simulations. Comparing with the VDR model, our new model has a better traffic efficiency and shows richer complex characters.
文摘The water gas shift （WGS） reaction is reacts with water on a catalytic surface a process of industrial importance to form CO2 and H2. We study this In this reaction carbon monoxide reaction with thermal （Langmuir- Hinshelwood） and non-thermal （precursor and Eley-Rideal） reaction mechanisms using the techniques of Monte Carlo computer simulation. The details of surface coverages and production rates are given as a function of CO partial pressure. The diffusion of species on the surface as well as their desorption from the surface is also introduced to include temperature effects. The phase diagrams of the system have been drawn to observe the behaviour of reacting species on the surface. The study reveals that the production rates are higher for non-thermal precursor mechanism and are in agreement with the experimental finding.
基金Supported by the National Natural Science Foundation of China under Grant No 20050284003.
文摘Moessbauer studies on the effect of substitution with 3% Al, Co, Mn atoms in the intermetallic compound of Hf0.8Ta0.2Fe2 are reported. The Al substitution leads to increase of the FM-AFM transition temperature and to decrease of the AFM-PM transition temperature. The Co substitution leads to disappearance of the FM state, only showing some FM impurity component, while Mn substituted compound indicates coexistence of FM and AFM states at low temperature. The phenomena imply complex itinerant electron properties in these magnetic systems.
