In this paper,the liquid–vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method.Physically,the multiphase shear flow is governed by two competing...In this paper,the liquid–vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method.Physically,the multiphase shear flow is governed by two competing mechanisms:surface tension and shear force.It is interesting to find that the liquid tends to form a droplet when the surface tension dominates under conditions of low temperature,shear velocity,and viscosity,and in larger domain size.Otherwise,the liquid tends to form a band if shear force dominates.Moreover,the average density gradient is used as a physical criterion to distinguish the spinodal decomposition and domain growth.Both spatial and temporal changes of density are studied during the phase separation under shear.展开更多
Bacterial spores commonly co-exist with vegetative cells,presenting challenges in spore separation and detection.The separation of spores is a crucial process for laboratory research and the detection of spore mechani...Bacterial spores commonly co-exist with vegetative cells,presenting challenges in spore separation and detection.The separation of spores is a crucial process for laboratory research and the detection of spore mechanisms.This study introduced a novel method that leverages the high binding affinity of vancomycin(Van)and ampicillin sodium(Amp)to vegetative cells,integrated with magnetic separation technology,to selectively collect spores from complex environments by eliminating vegetative cells.First,Van/Amp-modified magnetic Fe_(3)O_(4) nanoparticles(Fe_(3)O_(4) NPs)were synthesized and characterized.Subsequently,these NPs bound vegetative cells,forming magnetic conjugates that could be efficiently removed using a magnetic field.Concurrently,spores were collected with an efficiency exceeding 95%,completing the entire process within 30 min and achieving a spore separation efficiency of up to 10^(5) CFU/mL.This method was successfully applied to actual samples,including tap water and milk.The state of the collected spores was confirmed using Raman spectroscopy and microscopic techniques,verifying that their characteristics matched those of typical spores.The proposed novel method for rapid spore separation,leveraging the"remove bacterial effect'facilitated by Van/Amp-Fe_(3)O_(4) NPs,showed outstanding spore collection capabilities while preserving the excellent physiological state of spores.展开更多
This study successfully deals with the inhomogeneous dimension problem of load separation assumption, which is the theoretical basis of the normalization method. According to the dimensionless load separation principl...This study successfully deals with the inhomogeneous dimension problem of load separation assumption, which is the theoretical basis of the normalization method. According to the dimensionless load separation principle, the normalization method has been improved by intro- ducing a forcible blunting correction. With the improved normalization method, the J-resistance curves of five different metallic materials of CT and SEB specimens are estimated. The forcible blunting correction of initial crack size plays an important role in the J-resistance curve estima- tion, which is closely related to the strain hardening level of material. The higher level of strain hardening leads to a greater difference in JQ determined by different slopes of the blunting line. If the blunting line coefficient recommended by ASTM E1820-11 is used in the improved nor- realization method, it will lead to greater fracture resistance than that processed by the blunting line coefficient recommended by ISO 12135-2002. Therefore, the influence of the blunting line on the determination of JQ must be taken into full account in the fracture toughness assessment of metallic materials.展开更多
High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve t...High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.展开更多
The eigenvalue problem of an infinite-dimensional Hamiltonian operator appearing in the isotropic plane magnetoelectroelastic solids is studied. First, all the eigenvalues and their eigenfunctions in a rectangular dom...The eigenvalue problem of an infinite-dimensional Hamiltonian operator appearing in the isotropic plane magnetoelectroelastic solids is studied. First, all the eigenvalues and their eigenfunctions in a rectangular domain are solved directly. Then the completeness of the eigenfunction system is proved, which offers a theoretic guarantee of the feasibility of variable separation method based on a Hamiltonian system for isotropic plane magnetoelectroelastic solids. Finally, the general solution for the equation in the rectangular domain is obtained by using the symplectic Fourier expansion method.展开更多
Recovery processes of secondary resources usually encounter problems because of the diverse com- positions of wastes. To enhance the applicability of tradi- tional hydrometallurgical process toward secondary resources...Recovery processes of secondary resources usually encounter problems because of the diverse com- positions of wastes. To enhance the applicability of tradi- tional hydrometallurgical process toward secondary resources, the adjustment of components is necessary. In traditional hydrometallurgical separation, precipitation and complexation are extensively used. However, their com- bination as a specific metal separation method has not yet been studied in detail. This approach is very promising for solving problems caused by changeable components during recycling processes of secondary resources. This paper reviews the effects of precipitation and complexation in metal separation processes, and a metal separation method system of ＂complexation-precipitation＂ developed to adjust the components of secondary resources is introduced.展开更多
Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to n...Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to nonlinear wave equations with variable speed and external force. A complete classification for the wave equation which admits functional separable solutions is presented. Some known results can be recovered by this approach.展开更多
The discrimination of neutrons from gamma rays in a mixed radiation field is crucial in neutron detection tasks.Several approaches have been proposed to enhance the performance and accuracy of neutron-gamma discrimina...The discrimination of neutrons from gamma rays in a mixed radiation field is crucial in neutron detection tasks.Several approaches have been proposed to enhance the performance and accuracy of neutron-gamma discrimination.However,their performances are often associated with certain factors,such as experimental requirements and resulting mixed signals.The main purpose of this study is to achieve fast and accurate neutron-gamma discrimination without a priori information on the signal to be analyzed,as well as the experimental setup.Here,a novel method is proposed based on two concepts.The first method exploits the power of nonnegative tensor factorization(NTF)as a blind source separation method to extract the original components from the mixture signals recorded at the output of the stilbene scintillator detector.The second one is based on the principles of support vector machine(SVM)to identify and discriminate these components.In addition to these two main methods,we adopted the Mexican-hat function as a continuous wavelet transform to characterize the components extracted using the NTF model.The resulting scalograms are processed as colored images,which are segmented into two distinct classes using the Otsu thresholding method to extract the features of interest of the neutrons and gamma-ray components from the background noise.We subsequently used principal component analysis to select the most significant of these features wich are used in the training and testing datasets for SVM.Bias-variance analysis is used to optimize the SVM model by finding the optimal level of model complexity with the highest possible generalization performance.In this framework,the obtained results have verified a suitable bias–variance trade-off value.We achieved an operational SVM prediction model for neutron-gamma classification with a high true-positive rate.The accuracy and performance of the SVM based on the NTF was evaluated and validated by comparing it to the charge comparison method via figure of merit.The results indicate that the proposed approach has a superior discrimination quality(figure of merit of 2.20).展开更多
The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test methods.One is the Freedrop Test(FDT),which is known as unsteady and time-dependent method of scaled ...The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test methods.One is the Freedrop Test(FDT),which is known as unsteady and time-dependent method of scaled model.The other is the Captive Trajectory System(CTS)test,which is usually regarded as a quasi-steady and time-averaged test technology.The result shows that there is a streamwise adverse pressure gradient on the cavity resulting in a nose-up pitching moment coefficient(>0)acting on the store model.When the initial pitch angular velocity is 0,the store exits the shear-layer with a nose-up pitch attitude causing the store to climb back towards and collide with the aircraft.However,the store passes through the shear-layer into the freestream with a nose-down pitch,which causes a successful separation event when the initial pitch angular velocity<0.The pitch angle obtained by unsteady test method is different from that by quasisteady test method.The time-dependent test includes the aerodynamic force induced by pitch angular velocity whereas the time-averaged method(CTS)cannot reflect the effect of unsteady aerodynamic force.The deviation of vertical displacement is not obvious for FDT and CTS test since the store has an initial vertical velocity,which is dominant for the vertical displacement.This means that the highly unsteady flow can create unpredictability in aerodynamic pitching moment of the store,which can lead to the deviation of pitch angle for internal store separation.展开更多
Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were f...Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were forced to collide and coalesce with the Isopar oil droplets of core material in the continuous wates phase. When two kinds of oil droplets are collided and coalesced with each other, expanded polystyrene dissolved in the limonene oil may be phase-separated in the oil droplets newly formed to form the microcapsule shell, because the Isopar oil was a poor solvent for expanded polystyrene but a good solvent for the limonene oil. In the experiment, the diameter (or number) of limonene oil droplets dissolving expanded polystyrene was mainly changed, because the coalescence frequency between the droplets is strongly dependent on the number of droplets. Favorable core shell types of microcapsules with the shell thickness from 1.0 to 5.0 μm were able to be prepared under all the experimental conditions adopted here.展开更多
Privilege user is needed to manage the commercial transactions, but a super-administrator may have monopolize power and cause serious security problem. Relied on trusted computing technology, a privilege separation me...Privilege user is needed to manage the commercial transactions, but a super-administrator may have monopolize power and cause serious security problem. Relied on trusted computing technology, a privilege separation method is proposed to satisfy the security management requirement for information systems. It authorizes the system privilege to three different managers, and none of it can be interfered by others. Process algebra Communication Sequential Processes is used to model the three powers mechanism, and safety effect is analyzed and compared.展开更多
One of the main challenges in oil-water separation of traditional Chinese medicines(TCM)is to obtain essential oils from the aromatic water of TCM.In this study,silicon dioxide/polyvinylidene fluoride(SiO_(2)/PVDF)mem...One of the main challenges in oil-water separation of traditional Chinese medicines(TCM)is to obtain essential oils from the aromatic water of TCM.In this study,silicon dioxide/polyvinylidene fluoride(SiO_(2)/PVDF)membranes were prepared using nonsolvent induce phase separation.Then polydimethylsiloxane(PDMS)was coated to obtain PDMS/SiO_(2/)PVDF membranes.Separated essential oils and water from aromatic water in the gaseous state by vapor permeation membrane separation technology.The relationship between membrane structure and membrane separation effect was investigated.Response surface methodology was used to develop a quadratic model for the separation factor,membrane permeation separation index and membrane preparation process.The optimal process parameters for the membrane separation were 12.31%(mass)concentration of PVDF solution,9.6%(mass)of N,Ndimethylacetamide in the solidification bath,and 0.2 g hydrophobic nano-SiO_(2)incorporation,with a separation factor of 14.45,and a membrane flux of 1203.04 g·m^(-2)·h^(-1).Compared with the PDMS/PVDF membranes,the separation factor and membrane flux were increased by 68.59%and 3.46%,respectively.Compared with the SiO_(2)/PVDF membranes,the separation factor and membrane flux were increased by478%and 79.33%,respectively.Effectively mitigated the limitations of traditional polymer membrane material performance affected by the"trade-off"effect.Attenuated total internal reflection-Fourier transform infrared spectroscopy,contact angle,scanning electron microscopy and energy dispersive spectroscopy were used to characterize the PDMS/SiO_(2)/PVDF membranes,and gas chromatography was used to characterize the permeate.In addition,the contents of L-menthol,L-menthone,menthyl acetate and limonene in the permeate,conformed to the European Pharmacopoeia standards.This study provided an effective preparation strategy of a feasible hydrophobic powder polymer membrane for the separation of essential oils from gaseous peppermint aromatic water.展开更多
By the separation of singularity, a special Fourier series solution of the boundary value problem for plane is obtained, which can satisfy all boundary conditions and converges rapidly. II is proved that the solution ...By the separation of singularity, a special Fourier series solution of the boundary value problem for plane is obtained, which can satisfy all boundary conditions and converges rapidly. II is proved that the solution is equal to the result of separation of variables. As a result, the non-linear characteristic equations resulting from the method of separation of variables are transformed into polynomial equations that can provide a foundation for approximate computation and asymptotic analysis.展开更多
As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naph...As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.展开更多
Wave reflection is one of the key problems affecting wave simulation quality in ocean engineering basin. The deep ocean engineering basin is equipped with two-sided segmented wavemakers and two wave absorbing beaches,...Wave reflection is one of the key problems affecting wave simulation quality in ocean engineering basin. The deep ocean engineering basin is equipped with two-sided segmented wavemakers and two wave absorbing beaches, which are located opposite to wave generators to reduce wave reflection effects. When an oblique longcrested wave is made by two-sided segmented wavemakers in a wave basin, two bi-directional reflected waves with the same azimuth but opposite propagation directions are generated. According to this feature, based on the two-point approach developed by Goda, a method to separate an incident regular wave from two bi-directional reflected waves using three wave gauges is proposed. The validity of this method is proved by numerical composite waves. The results indicate that the method can separate incident wave from reflected waves effectively. The method can be used to determine the reflection coefficient and verify the capacity of wave absorbing beaches in deep ocean engineering basin.展开更多
Finding exact solutions for Riemann–Liouville(RL)fractional equations is very difficult.We propose a general method of separation of variables to study the problem.We obtain several general results and,as application...Finding exact solutions for Riemann–Liouville(RL)fractional equations is very difficult.We propose a general method of separation of variables to study the problem.We obtain several general results and,as applications,we give nontrivial exact solutions for some typical RL fractional equations such as the fractional Kadomtsev–Petviashvili equation and the fractional Langmuir chain equation.In particular,we obtain non-power functions solutions for a kind of RL time-fractional reaction–diffusion equation.In addition,we find that the separation of variables method is more suited to deal with high-dimensional nonlinear RL fractional equations because we have more freedom to choose undetermined functions.展开更多
The stabilization effect of a strong HF electric field on beam-plasma instability in a cylindrical warm plasma waveguide is discussed. A mathematical technique “separation method” applied to the two-fluid plasma mod...The stabilization effect of a strong HF electric field on beam-plasma instability in a cylindrical warm plasma waveguide is discussed. A mathematical technique “separation method” applied to the two-fluid plasma model to separate the equations, which describe the system, into two parts, temporal and space parts. Plasma electrons are considered to have a thermal velocity. It is shown that a HF electric field has no essential influence on dispersion characteristics of unstable surface waves excited in a warm plasma waveguide by a low-density electron beam. The region of instability only slightly narrowing and the growth rate decreases by a small parameter and this result has been reduced compared to cold plasma. Also, it is found that the plasma electrons have not affected the solution of the space part of the problem.展开更多
Research on the separation of tungstenand molybdenum is of importance as it is a ba-sic problem in the metallurgy and industry oftungsten.Traditional methods for the separa-tion include precipitation with sulfides and...Research on the separation of tungstenand molybdenum is of importance as it is a ba-sic problem in the metallurgy and industry oftungsten.Traditional methods for the separa-tion include precipitation with sulfides andsolvent extraction.There are,however,certaindisadvantages for these methods.A novelmethod was developed based on another展开更多
Through the analysis of roundness error separation technique of three-point method and based on the invariability and periodicity of the geometrical characteristic of measured round contour, a new matrix algorithm, wh...Through the analysis of roundness error separation technique of three-point method and based on the invariability and periodicity of the geometrical characteristic of measured round contour, a new matrix algorithm, which can be used to solve directly the roundness of the measured round contour without Fourier transform, is presented. On the basis of the research and analysis of the rotation error movement which is separated by using the three-point method, a mathematical equation is derived, which can be used to separate the eccentric motion of least square center of measured round contour and the pure rotation motion error of spindle in rotation motion. The correctness of this method is validated by means of simulation.展开更多
A new method for separating complex touching equiaxed and lamellar alpha phases in the optical micrograph of titanium alloy was proposed for quantitative characterization. This new method involves three steps. First, ...A new method for separating complex touching equiaxed and lamellar alpha phases in the optical micrograph of titanium alloy was proposed for quantitative characterization. This new method involves three steps. First, concave points of the microstructural feature are identified with a threshold of the concaveness of the comer points which are extracted from the binarized image. Secondly, concave points pairs are selected from the concave points group established by means of marker circle or distance. Third, whether a candidate separation line which connects two concave points within a pair can be accepted or not is determined by the proposed four rules. The obtained results show that this method is effective on separating complex touching microstructural features.展开更多
基金supported by National Natural Science Foundation of China under Grant No.51806116Guangdong Basic and Applied Basic Research Foundation under Grant No.2024A1515010927+2 种基金China Scholarship Council under Grant No.202306380288Humanities and Social Science Foundation of the Ministry of Education in China under Grant No.24YJCZH163Fundamental Research Funds for the Central Universities,Sun Yat-sen University under Grant No.24qnpy044。
文摘In this paper,the liquid–vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method.Physically,the multiphase shear flow is governed by two competing mechanisms:surface tension and shear force.It is interesting to find that the liquid tends to form a droplet when the surface tension dominates under conditions of low temperature,shear velocity,and viscosity,and in larger domain size.Otherwise,the liquid tends to form a band if shear force dominates.Moreover,the average density gradient is used as a physical criterion to distinguish the spinodal decomposition and domain growth.Both spatial and temporal changes of density are studied during the phase separation under shear.
基金supported by the General Program of National Natural Science Foundation of China(32472417)the Major Science and Technology Projects in Henan Province(221100110500,231100110400)+2 种基金the Science and Technology Innovation Team of Henan Universities(22IRTSTHN021)the Science and Technology of Henan Province(232102110136)Henan Provincial Joint Fund(Science and Technology Tackling)Category(232103810023).
文摘Bacterial spores commonly co-exist with vegetative cells,presenting challenges in spore separation and detection.The separation of spores is a crucial process for laboratory research and the detection of spore mechanisms.This study introduced a novel method that leverages the high binding affinity of vancomycin(Van)and ampicillin sodium(Amp)to vegetative cells,integrated with magnetic separation technology,to selectively collect spores from complex environments by eliminating vegetative cells.First,Van/Amp-modified magnetic Fe_(3)O_(4) nanoparticles(Fe_(3)O_(4) NPs)were synthesized and characterized.Subsequently,these NPs bound vegetative cells,forming magnetic conjugates that could be efficiently removed using a magnetic field.Concurrently,spores were collected with an efficiency exceeding 95%,completing the entire process within 30 min and achieving a spore separation efficiency of up to 10^(5) CFU/mL.This method was successfully applied to actual samples,including tap water and milk.The state of the collected spores was confirmed using Raman spectroscopy and microscopic techniques,verifying that their characteristics matched those of typical spores.The proposed novel method for rapid spore separation,leveraging the"remove bacterial effect'facilitated by Van/Amp-Fe_(3)O_(4) NPs,showed outstanding spore collection capabilities while preserving the excellent physiological state of spores.
基金supported by the National Natural Science Foundation of China(Nos.11472228 and 11202174)the Sichuan Provincial Youth Science and Technology Innovation Team(No.2013TD0004)
文摘This study successfully deals with the inhomogeneous dimension problem of load separation assumption, which is the theoretical basis of the normalization method. According to the dimensionless load separation principle, the normalization method has been improved by intro- ducing a forcible blunting correction. With the improved normalization method, the J-resistance curves of five different metallic materials of CT and SEB specimens are estimated. The forcible blunting correction of initial crack size plays an important role in the J-resistance curve estima- tion, which is closely related to the strain hardening level of material. The higher level of strain hardening leads to a greater difference in JQ determined by different slopes of the blunting line. If the blunting line coefficient recommended by ASTM E1820-11 is used in the improved nor- realization method, it will lead to greater fracture resistance than that processed by the blunting line coefficient recommended by ISO 12135-2002. Therefore, the influence of the blunting line on the determination of JQ must be taken into full account in the fracture toughness assessment of metallic materials.
基金financially supported by the National Natural Science Foundation of China (Nos. 51422403, 51774078 and U1508217)the Fundamental Research Funds for the Central Universities (No. N162505002)
文摘High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.
基金supported by the National Natural Science Foundation of China (Grant No 10562002)the Natural Science Foundation of Inner Mongolia, China (Grant No 200508010103)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No 20070126002)the Inner Mongolia University Doctoral Scientific Research Starting Foundation
文摘The eigenvalue problem of an infinite-dimensional Hamiltonian operator appearing in the isotropic plane magnetoelectroelastic solids is studied. First, all the eigenvalues and their eigenfunctions in a rectangular domain are solved directly. Then the completeness of the eigenfunction system is proved, which offers a theoretic guarantee of the feasibility of variable separation method based on a Hamiltonian system for isotropic plane magnetoelectroelastic solids. Finally, the general solution for the equation in the rectangular domain is obtained by using the symplectic Fourier expansion method.
基金financially supported by the National High-tech R&D Program of China(No.2013AA040208)the National Natural Science Foundation of China(No.51304010)the Beijing Natural Science Foundation(No.2132016)
文摘Recovery processes of secondary resources usually encounter problems because of the diverse com- positions of wastes. To enhance the applicability of tradi- tional hydrometallurgical process toward secondary resources, the adjustment of components is necessary. In traditional hydrometallurgical separation, precipitation and complexation are extensively used. However, their com- bination as a specific metal separation method has not yet been studied in detail. This approach is very promising for solving problems caused by changeable components during recycling processes of secondary resources. This paper reviews the effects of precipitation and complexation in metal separation processes, and a metal separation method system of ＂complexation-precipitation＂ developed to adjust the components of secondary resources is introduced.
文摘Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to nonlinear wave equations with variable speed and external force. A complete classification for the wave equation which admits functional separable solutions is presented. Some known results can be recovered by this approach.
基金L’Ore´al-UNESCO for the Women in Science Maghreb Program Grant Agreement No.4500410340.
文摘The discrimination of neutrons from gamma rays in a mixed radiation field is crucial in neutron detection tasks.Several approaches have been proposed to enhance the performance and accuracy of neutron-gamma discrimination.However,their performances are often associated with certain factors,such as experimental requirements and resulting mixed signals.The main purpose of this study is to achieve fast and accurate neutron-gamma discrimination without a priori information on the signal to be analyzed,as well as the experimental setup.Here,a novel method is proposed based on two concepts.The first method exploits the power of nonnegative tensor factorization(NTF)as a blind source separation method to extract the original components from the mixture signals recorded at the output of the stilbene scintillator detector.The second one is based on the principles of support vector machine(SVM)to identify and discriminate these components.In addition to these two main methods,we adopted the Mexican-hat function as a continuous wavelet transform to characterize the components extracted using the NTF model.The resulting scalograms are processed as colored images,which are segmented into two distinct classes using the Otsu thresholding method to extract the features of interest of the neutrons and gamma-ray components from the background noise.We subsequently used principal component analysis to select the most significant of these features wich are used in the training and testing datasets for SVM.Bias-variance analysis is used to optimize the SVM model by finding the optimal level of model complexity with the highest possible generalization performance.In this framework,the obtained results have verified a suitable bias–variance trade-off value.We achieved an operational SVM prediction model for neutron-gamma classification with a high true-positive rate.The accuracy and performance of the SVM based on the NTF was evaluated and validated by comparing it to the charge comparison method via figure of merit.The results indicate that the proposed approach has a superior discrimination quality(figure of merit of 2.20).
文摘The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test methods.One is the Freedrop Test(FDT),which is known as unsteady and time-dependent method of scaled model.The other is the Captive Trajectory System(CTS)test,which is usually regarded as a quasi-steady and time-averaged test technology.The result shows that there is a streamwise adverse pressure gradient on the cavity resulting in a nose-up pitching moment coefficient(>0)acting on the store model.When the initial pitch angular velocity is 0,the store exits the shear-layer with a nose-up pitch attitude causing the store to climb back towards and collide with the aircraft.However,the store passes through the shear-layer into the freestream with a nose-down pitch,which causes a successful separation event when the initial pitch angular velocity<0.The pitch angle obtained by unsteady test method is different from that by quasisteady test method.The time-dependent test includes the aerodynamic force induced by pitch angular velocity whereas the time-averaged method(CTS)cannot reflect the effect of unsteady aerodynamic force.The deviation of vertical displacement is not obvious for FDT and CTS test since the store has an initial vertical velocity,which is dominant for the vertical displacement.This means that the highly unsteady flow can create unpredictability in aerodynamic pitching moment of the store,which can lead to the deviation of pitch angle for internal store separation.
文摘Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were forced to collide and coalesce with the Isopar oil droplets of core material in the continuous wates phase. When two kinds of oil droplets are collided and coalesced with each other, expanded polystyrene dissolved in the limonene oil may be phase-separated in the oil droplets newly formed to form the microcapsule shell, because the Isopar oil was a poor solvent for expanded polystyrene but a good solvent for the limonene oil. In the experiment, the diameter (or number) of limonene oil droplets dissolving expanded polystyrene was mainly changed, because the coalescence frequency between the droplets is strongly dependent on the number of droplets. Favorable core shell types of microcapsules with the shell thickness from 1.0 to 5.0 μm were able to be prepared under all the experimental conditions adopted here.
文摘Privilege user is needed to manage the commercial transactions, but a super-administrator may have monopolize power and cause serious security problem. Relied on trusted computing technology, a privilege separation method is proposed to satisfy the security management requirement for information systems. It authorizes the system privilege to three different managers, and none of it can be interfered by others. Process algebra Communication Sequential Processes is used to model the three powers mechanism, and safety effect is analyzed and compared.
基金supported by the National Natural Science Foundation of China(22478007)the National Key Research and Development Program of China(2022YFB3805100)the Anhui Provincial Natural Science Foundation(2023AH050728)。
文摘One of the main challenges in oil-water separation of traditional Chinese medicines(TCM)is to obtain essential oils from the aromatic water of TCM.In this study,silicon dioxide/polyvinylidene fluoride(SiO_(2)/PVDF)membranes were prepared using nonsolvent induce phase separation.Then polydimethylsiloxane(PDMS)was coated to obtain PDMS/SiO_(2/)PVDF membranes.Separated essential oils and water from aromatic water in the gaseous state by vapor permeation membrane separation technology.The relationship between membrane structure and membrane separation effect was investigated.Response surface methodology was used to develop a quadratic model for the separation factor,membrane permeation separation index and membrane preparation process.The optimal process parameters for the membrane separation were 12.31%(mass)concentration of PVDF solution,9.6%(mass)of N,Ndimethylacetamide in the solidification bath,and 0.2 g hydrophobic nano-SiO_(2)incorporation,with a separation factor of 14.45,and a membrane flux of 1203.04 g·m^(-2)·h^(-1).Compared with the PDMS/PVDF membranes,the separation factor and membrane flux were increased by 68.59%and 3.46%,respectively.Compared with the SiO_(2)/PVDF membranes,the separation factor and membrane flux were increased by478%and 79.33%,respectively.Effectively mitigated the limitations of traditional polymer membrane material performance affected by the"trade-off"effect.Attenuated total internal reflection-Fourier transform infrared spectroscopy,contact angle,scanning electron microscopy and energy dispersive spectroscopy were used to characterize the PDMS/SiO_(2)/PVDF membranes,and gas chromatography was used to characterize the permeate.In addition,the contents of L-menthol,L-menthone,menthyl acetate and limonene in the permeate,conformed to the European Pharmacopoeia standards.This study provided an effective preparation strategy of a feasible hydrophobic powder polymer membrane for the separation of essential oils from gaseous peppermint aromatic water.
基金Supported by the National Natural Science Foundation of Chinathe Doctoral Training of the State Education Commission of China
文摘By the separation of singularity, a special Fourier series solution of the boundary value problem for plane is obtained, which can satisfy all boundary conditions and converges rapidly. II is proved that the solution is equal to the result of separation of variables. As a result, the non-linear characteristic equations resulting from the method of separation of variables are transformed into polynomial equations that can provide a foundation for approximate computation and asymptotic analysis.
基金support of the National Natural Science Foundation of China(Nos.22378369 and 22205207)Major Project of Natural Science Foundation of Zhejiang Province(LD24B060001).
文摘As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.
基金the National Natural Science Foundation of China(No.51239007)
文摘Wave reflection is one of the key problems affecting wave simulation quality in ocean engineering basin. The deep ocean engineering basin is equipped with two-sided segmented wavemakers and two wave absorbing beaches, which are located opposite to wave generators to reduce wave reflection effects. When an oblique longcrested wave is made by two-sided segmented wavemakers in a wave basin, two bi-directional reflected waves with the same azimuth but opposite propagation directions are generated. According to this feature, based on the two-point approach developed by Goda, a method to separate an incident regular wave from two bi-directional reflected waves using three wave gauges is proposed. The validity of this method is proved by numerical composite waves. The results indicate that the method can separate incident wave from reflected waves effectively. The method can be used to determine the reflection coefficient and verify the capacity of wave absorbing beaches in deep ocean engineering basin.
文摘Finding exact solutions for Riemann–Liouville(RL)fractional equations is very difficult.We propose a general method of separation of variables to study the problem.We obtain several general results and,as applications,we give nontrivial exact solutions for some typical RL fractional equations such as the fractional Kadomtsev–Petviashvili equation and the fractional Langmuir chain equation.In particular,we obtain non-power functions solutions for a kind of RL time-fractional reaction–diffusion equation.In addition,we find that the separation of variables method is more suited to deal with high-dimensional nonlinear RL fractional equations because we have more freedom to choose undetermined functions.
文摘The stabilization effect of a strong HF electric field on beam-plasma instability in a cylindrical warm plasma waveguide is discussed. A mathematical technique “separation method” applied to the two-fluid plasma model to separate the equations, which describe the system, into two parts, temporal and space parts. Plasma electrons are considered to have a thermal velocity. It is shown that a HF electric field has no essential influence on dispersion characteristics of unstable surface waves excited in a warm plasma waveguide by a low-density electron beam. The region of instability only slightly narrowing and the growth rate decreases by a small parameter and this result has been reduced compared to cold plasma. Also, it is found that the plasma electrons have not affected the solution of the space part of the problem.
文摘Research on the separation of tungstenand molybdenum is of importance as it is a ba-sic problem in the metallurgy and industry oftungsten.Traditional methods for the separa-tion include precipitation with sulfides andsolvent extraction.There are,however,certaindisadvantages for these methods.A novelmethod was developed based on another
基金Henan Innovation Project for University Prominent Research Talents (2004KYCX006)Ph.D.Inital Foundation of Henan University of Science &Techonologythe Natural Science Foundation of Henan Education Agency (2008A460007)
文摘Through the analysis of roundness error separation technique of three-point method and based on the invariability and periodicity of the geometrical characteristic of measured round contour, a new matrix algorithm, which can be used to solve directly the roundness of the measured round contour without Fourier transform, is presented. On the basis of the research and analysis of the rotation error movement which is separated by using the three-point method, a mathematical equation is derived, which can be used to separate the eccentric motion of least square center of measured round contour and the pure rotation motion error of spindle in rotation motion. The correctness of this method is validated by means of simulation.
基金Projects(50935007,51175428) supported by the National Natural Science Foundation of ChinaProject(2010CB731701) supported by the National Basic Research Program of ChinaProject(B08040) supported by the Program of Introducing Talents of Discipline to Universities,China
文摘A new method for separating complex touching equiaxed and lamellar alpha phases in the optical micrograph of titanium alloy was proposed for quantitative characterization. This new method involves three steps. First, concave points of the microstructural feature are identified with a threshold of the concaveness of the comer points which are extracted from the binarized image. Secondly, concave points pairs are selected from the concave points group established by means of marker circle or distance. Third, whether a candidate separation line which connects two concave points within a pair can be accepted or not is determined by the proposed four rules. The obtained results show that this method is effective on separating complex touching microstructural features.
