MnO2/MnO cathode material with superior Zn^2+storage performance is prepared through a simple physical mixing method.The MnO2/MnO nanocomposite with a mixed mass ratio of 12:1 exhibits the highest specific capacity(36...MnO2/MnO cathode material with superior Zn^2+storage performance is prepared through a simple physical mixing method.The MnO2/MnO nanocomposite with a mixed mass ratio of 12:1 exhibits the highest specific capacity(364.2 mA·h/g at 0.2C),good cycle performance(170.4 mA·h/g after 100 cycles)and excellent rate performance(205.7 mA·h/g at 2C).Analysis of cyclic voltammetry(CV)data at various scan rates shows that both diffusioncontrolled insertion behavior and surface capacitive behavior contribute to the Zn2+storage performance of MnO2/MnO cathodes.And the capacitive behavior contributes more at high discharge rates,due to the short paths of ion diffusion and the rapid transfer of electrons.展开更多
The effects of three different mixing methods of CuO/ZnO/Al_(2)O_(3)(CZA)and HZSM-5 bifunctional catalyst on the stability for dimethyl ether(DME)synthesis from carbon dioxide(CO_(2))hydrogenation were investigated.Wh...The effects of three different mixing methods of CuO/ZnO/Al_(2)O_(3)(CZA)and HZSM-5 bifunctional catalyst on the stability for dimethyl ether(DME)synthesis from carbon dioxide(CO_(2))hydrogenation were investigated.When the bifunctional catalyst was prepared by method A(mixing powder without pelletization),there was no significant change in DME production and catalyst stability when the HZSM-5 loading was varied between 0.1 g and 0.5 g with a fixed CZA loading of 0.5 g,.When the bifunctional catalysts were prepared by method B(pressed into pellets of CZA and pellets of HZSM-5 and then mixed)and method C(mixed CZA and HZSM-5 powders,then pressed into pellets),the mixing methods did not initially impact CO_(2)conversion and had a minor effect on DME yield.However,long-term tests(100 h)indicated that the mixing method had a significant influence on the catalyst stability.Method B showed the best stability and the extent of catalyst deactivation followed the sequence of method B<method A<method C.Characterizations of spent catalysts indicated that method B could reduce the extent of copper(Cu)oxidation,which due to the relatively low surface contact between Cu active sites and HZSM-5.Large amounts of water generated in CO_(2)hydrogenation to synthesize DME and intimate contact between CZA and HZSM-5 catalyst could induce severe oxidation of Cu and metal ions migration from hydrogenation catalyst to HZSM-5,which can result in the number reduction of acidic sites.展开更多
Discontinuous Galerkin（DG） method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is deve...Discontinuous Galerkin（DG） method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is developed for numerical simulations of both temporally and spatially developing mixing layers. For the temporally developing mixing layer,both the instantaneous fiow field and time evolution of momentum thickness agree very well with the previous results. Shocklets are observed at higher convective Mach numbers and the vortex paring manner is changed for high compressibility. For the spatially developing mixing layer,large-scale coherent structures and self-similar behavior for mean profiles are investigated. The instantaneous fiow field for a three-dimensional compressible mixing layer is also reported,which shows the development of largescale coherent structures in the streamwise direction. All numerical results suggest that the DG method is effective in performing accurate numerical simulations for compressible shear fiows.展开更多
Mixing brine method,which founded on the commonion effect,is widely used for low-sodium carnallite production.Compared with traditional carnallite preparation techniques,the mixing brine method possess a
In this paper,a composite numerical scheme is proposed to solve the threedimensional Darcy-Forchheimer miscible displacement problem with positive semi-definite assumptions.A mixed finite element is used for the fow e...In this paper,a composite numerical scheme is proposed to solve the threedimensional Darcy-Forchheimer miscible displacement problem with positive semi-definite assumptions.A mixed finite element is used for the fow equation.The velocity and pressure are computed simultaneously.The accuracy of velocity is improved one order.The concentration equation is solved by using mixed finite element,multi-step difference and upwind approximation.A multi-step method is used to approximate time derivative for improving the accuracy.The upwind approximation and an expanded mixed finite element are adopted to solve the convection and diffusion,respectively.The composite method could compute the diffusion flux and its gradient.It possibly becomes an eficient tool for solving convection-dominated diffusion problems.Firstly,the conservation of mass holds.Secondly,the multi-step method has high accuracy.Thirdly,the upwind approximation could avoid numerical dispersion.Using numerical analysis of a priori estimates and special techniques of differential equations,we give an error estimates for a positive definite problem.Numerical experiments illustrate its computational efficiency and feasibility of application.展开更多
The operator splitting method is used to deal with the Navier-Stokes equation, in which the physical process described by the equation is decomposed into two processes： a diffusion process and a convection process; a...The operator splitting method is used to deal with the Navier-Stokes equation, in which the physical process described by the equation is decomposed into two processes： a diffusion process and a convection process; and the finite element equation is established. The velocity field in the element is described by the shape function of the isoparametric element with nine nodes and the pressure field is described by the interpolation function of the four nodes at the vertex of the isoparametric element with nine nodes. The subroutine of the element and the integrated finite element code are generated by the Finite Element Program Generator （FEPG） successfully. The numerical simulation about the incompressible viscous liquid flowing over a cylinder is carded out. The solution agrees with the experimental results very well.展开更多
The double-alloy powder mixed method is very proper for developing new small-mass products by changing the composi- tion of sintered Nd-Fe-B magnets, and there is little research on this aspect. The variation on magne...The double-alloy powder mixed method is very proper for developing new small-mass products by changing the composi- tion of sintered Nd-Fe-B magnets, and there is little research on this aspect. The variation on magnetic and mechanical properties of high intrinsic coercivity Nd-Fe-B magnets prepared by double-alloy powder mixed method was discussed, which is a method blend- ing two-type main phase alloy powders with different components. The results showed that the intrinsic coercivity and density of sin- tered Nd-Fe-B magnets increased gradually with the increase in Dy content, and the double-alloy powder mixed method could obtain high intrinsic coercivity Nd-Fe-B magnets with good crystallographic alignment and microstructure. The bending strength of sintered Nd-Fe-B magnets declined, and the Rockwell hardness of sintered Nd-Fe-B magnets first declined, and then increased with the in- crease in Dy content. The microstructure showed that there existed the phenomenon that the Dy element diffused into main phase dur- ing sintering process, and the distribution of Dy content in main phase had some variation in homogeneity as a result of incomplete reaction between the double-alloy powder types.展开更多
Polycrystalline LuAG:Ce3+(cerium3+-doped lutetium aluminum garnet) powders were prepared by mixed solvo-thermal method.Fourier-transform IR spectroscopy(FTIR) and X-ray diffraction(XRD) measurements showed that the pr...Polycrystalline LuAG:Ce3+(cerium3+-doped lutetium aluminum garnet) powders were prepared by mixed solvo-thermal method.Fourier-transform IR spectroscopy(FTIR) and X-ray diffraction(XRD) measurements showed that the precursors were ethanol derivatives AlO(OH) crystal with hydroxyl and carbonate group.XRD results showed that phase of Lu2O3 disappeared with the precursors were annealed at 400 °C,cubic phase LuAG:Ce3+ appeared but only one diffraction peaks of LuAP(LuAlO3) at calcination temperature to 700 °C,a...展开更多
An H^1-Galerkin mixed finite element method is discussed for a class of second order SchrSdinger equation. Optimal error estimates of semidiscrete schemes are derived for problems in one space dimension. At the same t...An H^1-Galerkin mixed finite element method is discussed for a class of second order SchrSdinger equation. Optimal error estimates of semidiscrete schemes are derived for problems in one space dimension. At the same time, optimal error estimates are derived for fully discrete schemes. And it is showed that the H1-Galerkin mixed finite element approximations have the same rate of convergence as in the classical mixed finite element methods without requiring the LBB consistency condition.展开更多
The particle mixing was studied in a cylindrical stirred tank with elliptical dished bottom by experiments and simulations.The impeller types used were double helical ribbon(HR) + bottom HR,pitched blade ribbon + bott...The particle mixing was studied in a cylindrical stirred tank with elliptical dished bottom by experiments and simulations.The impeller types used were double helical ribbon(HR) + bottom HR,pitched blade ribbon + bottom HR,inner and outer HR + bottom HR,and pitched blade ribbon + Pfaudler + bottom HR labeled as impellers Ⅰ to Ⅳ,respectively.The quantitative correlations among the rotational speed,fill level and power consumption for impeller Ⅰ and impeller Ⅱ were obtained by experiments to validate the discrete element method(DEM) simulations.The particle mixing at different operating conditions was simulated via DEM simulations to calculate the mixing index using the Lacey method,which is a statistical method to provide a mathematical understanding of the mixing state in a binary mixture.The simulation results reveal that as the rotational speed increases,the final mixing index increases,and as the fill level increases,the final mixing index decreases.At the same operating conditions,impeller Ⅲ is the optimal combination,which provides the highest mixing index at the same revolutions.展开更多
The mixed covolume method for the regularized long wave equation is devel- oped and studied. By introducing a transfer operator γh, which maps the trial function space into the test function space, and combining the ...The mixed covolume method for the regularized long wave equation is devel- oped and studied. By introducing a transfer operator γh, which maps the trial function space into the test function space, and combining the mixed finite element with the finite volume method, the nonlinear and linear Euler fully discrete mixed covolume schemes are constructed, and the existence and uniqueness of the solutions are proved. The optimal error estimates for these schemes are obtained. Finally, a numerical example is provided to examine the efficiency of the proposed schemes.展开更多
This paper presents an adapted stabilisation method for the equal-order mixed scheme of finite elements on convex polygonal meshes to analyse the high velocity and pressure gradient of incompressible fluid flows that ...This paper presents an adapted stabilisation method for the equal-order mixed scheme of finite elements on convex polygonal meshes to analyse the high velocity and pressure gradient of incompressible fluid flows that are governed by Stokes equations system.This technique is constructed by a local pressure projection which is extremely simple,yet effective,to eliminate the poor or even non-convergence as well as the instability of equal-order mixed polygonal technique.In this research,some numerical examples of incompressible Stokes fluid flow that is coded and programmed by MATLAB will be presented to examine the effectiveness of the proposed stabilised method.展开更多
An H1-Galerkin expanded mixed finite element method is discussed for a class of second order semi-linear hyperbolic wave equations. By using the mixed formulation, we can get the optimal approximation for three variab...An H1-Galerkin expanded mixed finite element method is discussed for a class of second order semi-linear hyperbolic wave equations. By using the mixed formulation, we can get the optimal approximation for three variables: the scalar unknown, its gradient and its flux(coefficient times the gradient), simultaneously. We also prove the existence and uniqueness of semi-discrete solution. Finally, we obtain some numerical results to illustrate the efficiency of the method.展开更多
The purpose of this article is to develop and analyze least-squares approximations for the incompressible magnetohydrodynamic equations. The major advantage of the least-squares finite element method is that it is not...The purpose of this article is to develop and analyze least-squares approximations for the incompressible magnetohydrodynamic equations. The major advantage of the least-squares finite element method is that it is not subjected to the so-called Ladyzhenskaya-Babuska-Brezzi （LBB） condition. The authors employ least-squares functionals which involve a discrete inner product which is related to the inner product in H^-1（Ω）.展开更多
Objective:This study provides a preliminary evaluation of the usability and acceptability of a mobile application(sexual assault care algorithm,SACA).Methods:An explanatory sequential mixed methods research was used.A...Objective:This study provides a preliminary evaluation of the usability and acceptability of a mobile application(sexual assault care algorithm,SACA).Methods:An explanatory sequential mixed methods research was used.A quantitative survey was followed up by a qualitative study.A convenience sample of participants(n=4)was recruited.The research was conducted on a one-on-one basis.In the quantitative phase,a random assignment technique was used to divide four participants into two groups of two participants each.Post-Study System Usability Questionnaire(PSSUQ)and Acceptability e-Scale were used to collect quantitative data.In the qualitative phase,interview,observation,and documentation were used to collect qualitative data.Data were analyzed both quantitative and qualitatively.The qualitative data were linked with the initial quantitative data to determine how the follow-up qualitative data helped explain the initial quantitative results.Results:The quantitative results suggested that SACA has high usability(5.05±1.83)and acceptability(3.81±1.22).The qualitative results further indicate that the participants thought SACA was easy to use and useful,and most of them would recommend it to others.Areas of improvement include adding features that would calculate and validate the elapsed time since the sexual assault,adding explanations to some buttons,and providing training.Conclusions:Our findings highlight the value of using a mixed methods research design to conduct a usability and acceptability test.Nurses are more likely to adopt a new technology for their evidencebased practice when the technology is easy to use and useful and requires less time to find the right piece of guideline evidence.Individualized training needs to be designed based on users'characteristics.展开更多
OBJECTIVE:To update the current characteristics about the scope and quality of mixed methods research(MMR)in complementary and alternative medicine(CAM)after nearly 10 years.METHODS:A 5-stage approach for conducting a...OBJECTIVE:To update the current characteristics about the scope and quality of mixed methods research(MMR)in complementary and alternative medicine(CAM)after nearly 10 years.METHODS:A 5-stage approach for conducting a scoping review was adopted.Articles published on the top 10 journals in CAM with the highest impact factor in 2020 were screened for MMR.Information of included articles were extracted,and then synthesized to illustrate the current state.Methodological quality was evaluated according to the Mixed Method Appraisal Tool(MMAT)2018 version.RESULTS:A total of 55(55/2991,2%)articles using mixed methods were retrieved,including 17 medical studies and 38 ethnobotanical studies.We performed an in-depth analysis on the 17 medical studies,which studied cancer,stress,pain,fatigue,exercises,mindfulness intervention,herbal medicine use,art and acupuncture.Thirteen pilot studies applied MMR to evaluate the feasibility of interventions or programs(13/17,76%);phenomenology was inferred as the most common philosophical assumptions(13/17,76%);the most applied type of MMR was convergent design(16/17,94%);integration often took place at integration(12/17,71%).Among the 16 eligible studies for quality appraisal,majority were rated as good(14/16,88%),whereas two studies were rated as poorly described.Primarily,a poor rating was due to incomplete reporting of data analysis and citations in qualitative components;lack of confounder controlling and the sampling strategy in quantitative components;poor description of integration and justification for mixed methods.Comparing with the previous review,fewer MMR were published in 2020 in CAM,but the proportion of studies that clearly reported MMR has increased by 4 times(4%→15%).CONCLUSION:CAM researchers need to realize the benefits that MMR can have on conducting further health care research.Our findings highlight that applying MMR will be helpful to understand the complex dynamics and interdisciplinary nature of complex intervention.In addition,addressing a standardized reporting criteria for MMR is recommended.展开更多
Purpose'. To examine adolescent experiences and perspectives of the GoActive intervention (ISRCTN31583496) using mixed methods processevaluation to determine satisfaction with intervention components and interpret...Purpose'. To examine adolescent experiences and perspectives of the GoActive intervention (ISRCTN31583496) using mixed methods processevaluation to determine satisfaction with intervention components and interpret a*dolescents experiences of the intervention process in order toprovide insights for future intervention design.Methods'. Participants (n = 1542;13.2 土 0.4 years, mean 土 SD) provided questionnaire data at baseline (shyness, activity level) and post-intervention(intervention acceptability, satisfaction with components). Between-group differences (boys vs. girls and shy/inactive vs. others) weretested with linear regression models, accounting for school clustering. Data from 16 individual interviews (shy/inactive) and 11 focus groupswith 48 participants (mean = 4;range 2—7) were thematically coded. Qualitative and quantitative data were merged in an integrative mixedmethods convergence matrix, which denoted convergence and dissonance across datasets.Results'. Effect sizes for quantitative results were small and may not represent substantial between-group differences. Boys (vs. girls) preferredclass-based sessions (0 = 0.2, 95% confidence interval (CI): 0.1—0.3);qualitative data suggested that this was because boys preferred competition,which was supported quantitatively (0 = 0.2, 95%CI: 0.1-0.3). Shy/inactive students did not enjoy the competition (0 = -0.3, 95%CI:—0.5 to —0.1). Boys enjoyed trying new activities more (0 = 0.1, 95%CI: 0.1 -0.2);qualitative data indicated a desire to try new activities acrossall subgroups but identified barriers to choosing unfamiliar activities with self-imposed choice restriction leading to boredom. Qualitative datahighlighted critique of mentorship;adolescents liked the idea, but older mentors did not meet expectations.Conclusion. We interpreted adolescent perspectives of intervention components and implementation to provide insights into future complexinterventions aimed at increasing young people's physical activity in school-based settings. The intervention component mentorship was liked inprinciple, but implementation issues undesirably impacted satisfaction;competition was disliked by girls and shy/inactive students. The resultshighlight the importance of considering gender differences in preference of competition and extensive mentorship training.展开更多
H1-Galerkin mixed methods are proposed for viscoelasticity wave equation.Depending on the physical quantities of interest,two methods are discussed.The optimal error estimates and the proof of the existence and unique...H1-Galerkin mixed methods are proposed for viscoelasticity wave equation.Depending on the physical quantities of interest,two methods are discussed.The optimal error estimates and the proof of the existence and uniqueness of semidiscrete solutions are derived for problems in one space dimension.And the methods don＇t require the LBB condition.展开更多
A new algorithm for the solution of quadratic programming problemsis put forward in terms of the mixed energy theory and is furtherused for the incremental solution of elastic-plastic trussstructures. The method propo...A new algorithm for the solution of quadratic programming problemsis put forward in terms of the mixed energy theory and is furtherused for the incremental solution of elastic-plastic trussstructures. The method proposed is different from the traditionalone, for which the unknown variables are selected just in one classsuch as displacements or stresses. The present method selects thevariables in the mixed form with both displacement and stress. As themethod is established in the hybrid space, the information found inthe previous incremental step can be used for the solution of thepresent step, making the algorithm highly effi- cient in thenumerical solution process of quadratic programming problems. Theresults obtained in the exm- ples of the elastic-plastic solution ofthe truss structures verify what has been predicted in thetheoretical anal- ysis.展开更多
A mixed time discontinuous space-time finite element scheme for secondorder convection diffusion problems is constructed and analyzed. Order of the equation is lowered by the mixed finite element method. The low order...A mixed time discontinuous space-time finite element scheme for secondorder convection diffusion problems is constructed and analyzed. Order of the equation is lowered by the mixed finite element method. The low order equation is discretized with a space-time finite element method, continuous in space but discontinuous in time. Stability, existence, uniqueness and convergence of the approximate solutions are proved. Numerical results are presented to illustrate efficiency of the proposed method.展开更多
基金Project(21905304)supported by the National Natural Science Foundation of ChinaProject(ZR2019BEM031)supported by the Natural Science Foundation of Shandong Province,ChinaProjects(18CX02158A,19CX05001A)supported by the Fundamental Research Funds for the Central Universities,China。
文摘MnO2/MnO cathode material with superior Zn^2+storage performance is prepared through a simple physical mixing method.The MnO2/MnO nanocomposite with a mixed mass ratio of 12:1 exhibits the highest specific capacity(364.2 mA·h/g at 0.2C),good cycle performance(170.4 mA·h/g after 100 cycles)and excellent rate performance(205.7 mA·h/g at 2C).Analysis of cyclic voltammetry(CV)data at various scan rates shows that both diffusioncontrolled insertion behavior and surface capacitive behavior contribute to the Zn2+storage performance of MnO2/MnO cathodes.And the capacitive behavior contributes more at high discharge rates,due to the short paths of ion diffusion and the rapid transfer of electrons.
基金This work was supported by the U.S.Department of Energy through contract DE-AR0000806.
文摘The effects of three different mixing methods of CuO/ZnO/Al_(2)O_(3)(CZA)and HZSM-5 bifunctional catalyst on the stability for dimethyl ether(DME)synthesis from carbon dioxide(CO_(2))hydrogenation were investigated.When the bifunctional catalyst was prepared by method A(mixing powder without pelletization),there was no significant change in DME production and catalyst stability when the HZSM-5 loading was varied between 0.1 g and 0.5 g with a fixed CZA loading of 0.5 g,.When the bifunctional catalysts were prepared by method B(pressed into pellets of CZA and pellets of HZSM-5 and then mixed)and method C(mixed CZA and HZSM-5 powders,then pressed into pellets),the mixing methods did not initially impact CO_(2)conversion and had a minor effect on DME yield.However,long-term tests(100 h)indicated that the mixing method had a significant influence on the catalyst stability.Method B showed the best stability and the extent of catalyst deactivation followed the sequence of method B<method A<method C.Characterizations of spent catalysts indicated that method B could reduce the extent of copper(Cu)oxidation,which due to the relatively low surface contact between Cu active sites and HZSM-5.Large amounts of water generated in CO_(2)hydrogenation to synthesize DME and intimate contact between CZA and HZSM-5 catalyst could induce severe oxidation of Cu and metal ions migration from hydrogenation catalyst to HZSM-5,which can result in the number reduction of acidic sites.
基金supported by the National Natural Science Foundation of China (90716008,10572004 and 10921202)MOST 973 Project (2009CB724100) and CSSA
文摘Discontinuous Galerkin（DG） method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is developed for numerical simulations of both temporally and spatially developing mixing layers. For the temporally developing mixing layer,both the instantaneous fiow field and time evolution of momentum thickness agree very well with the previous results. Shocklets are observed at higher convective Mach numbers and the vortex paring manner is changed for high compressibility. For the spatially developing mixing layer,large-scale coherent structures and self-similar behavior for mean profiles are investigated. The instantaneous fiow field for a three-dimensional compressible mixing layer is also reported,which shows the development of largescale coherent structures in the streamwise direction. All numerical results suggest that the DG method is effective in performing accurate numerical simulations for compressible shear fiows.
基金Project supported by the Sichuan Youth Science and Technology Innovation Research Team Funding Scheme(2013TD0005)Innovation Team of CDUT(KYTD201405)
文摘Mixing brine method,which founded on the commonion effect,is widely used for low-sodium carnallite production.Compared with traditional carnallite preparation techniques,the mixing brine method possess a
基金supported by the Natural Science Foundation of Shandong Province(ZR2021MA019)the National Natural Science Foundation of China(11871312)。
文摘In this paper,a composite numerical scheme is proposed to solve the threedimensional Darcy-Forchheimer miscible displacement problem with positive semi-definite assumptions.A mixed finite element is used for the fow equation.The velocity and pressure are computed simultaneously.The accuracy of velocity is improved one order.The concentration equation is solved by using mixed finite element,multi-step difference and upwind approximation.A multi-step method is used to approximate time derivative for improving the accuracy.The upwind approximation and an expanded mixed finite element are adopted to solve the convection and diffusion,respectively.The composite method could compute the diffusion flux and its gradient.It possibly becomes an eficient tool for solving convection-dominated diffusion problems.Firstly,the conservation of mass holds.Secondly,the multi-step method has high accuracy.Thirdly,the upwind approximation could avoid numerical dispersion.Using numerical analysis of a priori estimates and special techniques of differential equations,we give an error estimates for a positive definite problem.Numerical experiments illustrate its computational efficiency and feasibility of application.
文摘The operator splitting method is used to deal with the Navier-Stokes equation, in which the physical process described by the equation is decomposed into two processes： a diffusion process and a convection process; and the finite element equation is established. The velocity field in the element is described by the shape function of the isoparametric element with nine nodes and the pressure field is described by the interpolation function of the four nodes at the vertex of the isoparametric element with nine nodes. The subroutine of the element and the integrated finite element code are generated by the Finite Element Program Generator （FEPG） successfully. The numerical simulation about the incompressible viscous liquid flowing over a cylinder is carded out. The solution agrees with the experimental results very well.
基金Project supported by the Natural Science Foundation of Hubei Province(2014CFB626,2015CFC785)the Research Project of Hubei Provincial Department of Education(D20151801)the Opening Foundation of Hubei Key Laboratory of Automotive Power Train and Electronic Control(ZDK1201404)
文摘The double-alloy powder mixed method is very proper for developing new small-mass products by changing the composi- tion of sintered Nd-Fe-B magnets, and there is little research on this aspect. The variation on magnetic and mechanical properties of high intrinsic coercivity Nd-Fe-B magnets prepared by double-alloy powder mixed method was discussed, which is a method blend- ing two-type main phase alloy powders with different components. The results showed that the intrinsic coercivity and density of sin- tered Nd-Fe-B magnets increased gradually with the increase in Dy content, and the double-alloy powder mixed method could obtain high intrinsic coercivity Nd-Fe-B magnets with good crystallographic alignment and microstructure. The bending strength of sintered Nd-Fe-B magnets declined, and the Rockwell hardness of sintered Nd-Fe-B magnets first declined, and then increased with the in- crease in Dy content. The microstructure showed that there existed the phenomenon that the Dy element diffused into main phase dur- ing sintering process, and the distribution of Dy content in main phase had some variation in homogeneity as a result of incomplete reaction between the double-alloy powder types.
基金supported by National Natural Science Foundation of China (10774140)Knowledge Innovation Project of the Chinese Academy of Sciences (KJCX2-YW-M11)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education (20060358054)Special Foundation for Talents of Anhui Province,China (2007Z021)
文摘Polycrystalline LuAG:Ce3+(cerium3+-doped lutetium aluminum garnet) powders were prepared by mixed solvo-thermal method.Fourier-transform IR spectroscopy(FTIR) and X-ray diffraction(XRD) measurements showed that the precursors were ethanol derivatives AlO(OH) crystal with hydroxyl and carbonate group.XRD results showed that phase of Lu2O3 disappeared with the precursors were annealed at 400 °C,cubic phase LuAG:Ce3+ appeared but only one diffraction peaks of LuAP(LuAlO3) at calcination temperature to 700 °C,a...
基金Supported by the National Natural Science Foundation of China (10601022)Natural Science Foundation of Inner Mongolia Autonomous Region (200607010106)Youth Science Foundation of Inner Mongolia University(ND0702)
文摘An H^1-Galerkin mixed finite element method is discussed for a class of second order SchrSdinger equation. Optimal error estimates of semidiscrete schemes are derived for problems in one space dimension. At the same time, optimal error estimates are derived for fully discrete schemes. And it is showed that the H1-Galerkin mixed finite element approximations have the same rate of convergence as in the classical mixed finite element methods without requiring the LBB consistency condition.
文摘The particle mixing was studied in a cylindrical stirred tank with elliptical dished bottom by experiments and simulations.The impeller types used were double helical ribbon(HR) + bottom HR,pitched blade ribbon + bottom HR,inner and outer HR + bottom HR,and pitched blade ribbon + Pfaudler + bottom HR labeled as impellers Ⅰ to Ⅳ,respectively.The quantitative correlations among the rotational speed,fill level and power consumption for impeller Ⅰ and impeller Ⅱ were obtained by experiments to validate the discrete element method(DEM) simulations.The particle mixing at different operating conditions was simulated via DEM simulations to calculate the mixing index using the Lacey method,which is a statistical method to provide a mathematical understanding of the mixing state in a binary mixture.The simulation results reveal that as the rotational speed increases,the final mixing index increases,and as the fill level increases,the final mixing index decreases.At the same operating conditions,impeller Ⅲ is the optimal combination,which provides the highest mixing index at the same revolutions.
基金supported by the National Natural Science Fundation of China (No. 11061021)the Science Research of Inner Mongolia Advanced Education (Nos. NJ10006, NJ10016, and NJZZ12011)the National Science Foundation of Inner Mongolia (Nos. 2011BS0102 and 2012MS0106)
文摘The mixed covolume method for the regularized long wave equation is devel- oped and studied. By introducing a transfer operator γh, which maps the trial function space into the test function space, and combining the mixed finite element with the finite volume method, the nonlinear and linear Euler fully discrete mixed covolume schemes are constructed, and the existence and uniqueness of the solutions are proved. The optimal error estimates for these schemes are obtained. Finally, a numerical example is provided to examine the efficiency of the proposed schemes.
基金The authors would like to present our gratitude to the Flemish Government financially supporting for the VLIR-OUS TEAM Project,VN2017TEA454A103‘An innovative solution to protect Vietnamese coastal riverbanks from floods and erosion’.
文摘This paper presents an adapted stabilisation method for the equal-order mixed scheme of finite elements on convex polygonal meshes to analyse the high velocity and pressure gradient of incompressible fluid flows that are governed by Stokes equations system.This technique is constructed by a local pressure projection which is extremely simple,yet effective,to eliminate the poor or even non-convergence as well as the instability of equal-order mixed polygonal technique.In this research,some numerical examples of incompressible Stokes fluid flow that is coded and programmed by MATLAB will be presented to examine the effectiveness of the proposed stabilised method.
基金Supported by the National Natural Science Fund(11061021)Supported by the Scientific Research Projection of Higher Schools of Inner Mongolia(NJZZ12011, NJ10006)+1 种基金Supported by the Program of Higher-level talents of Inner Mongolia University(125119)Supported by the Scientific Research Projection of Inner Mongolia University of Finance and Economics(KY1101)
文摘An H1-Galerkin expanded mixed finite element method is discussed for a class of second order semi-linear hyperbolic wave equations. By using the mixed formulation, we can get the optimal approximation for three variables: the scalar unknown, its gradient and its flux(coefficient times the gradient), simultaneously. We also prove the existence and uniqueness of semi-discrete solution. Finally, we obtain some numerical results to illustrate the efficiency of the method.
基金supported by the National Basic Research Program of China (2005CB321701)NSF of mathematics research special fund of Hebei Province(08M005)
文摘The purpose of this article is to develop and analyze least-squares approximations for the incompressible magnetohydrodynamic equations. The major advantage of the least-squares finite element method is that it is not subjected to the so-called Ladyzhenskaya-Babuska-Brezzi （LBB） condition. The authors employ least-squares functionals which involve a discrete inner product which is related to the inner product in H^-1（Ω）.
基金The development of the application for SACA was partially supported by funding from the Upstate Foundation,a 501(c)3 nonfor-profit corporation (upstatefoundation.org)
文摘Objective:This study provides a preliminary evaluation of the usability and acceptability of a mobile application(sexual assault care algorithm,SACA).Methods:An explanatory sequential mixed methods research was used.A quantitative survey was followed up by a qualitative study.A convenience sample of participants(n=4)was recruited.The research was conducted on a one-on-one basis.In the quantitative phase,a random assignment technique was used to divide four participants into two groups of two participants each.Post-Study System Usability Questionnaire(PSSUQ)and Acceptability e-Scale were used to collect quantitative data.In the qualitative phase,interview,observation,and documentation were used to collect qualitative data.Data were analyzed both quantitative and qualitatively.The qualitative data were linked with the initial quantitative data to determine how the follow-up qualitative data helped explain the initial quantitative results.Results:The quantitative results suggested that SACA has high usability(5.05±1.83)and acceptability(3.81±1.22).The qualitative results further indicate that the participants thought SACA was easy to use and useful,and most of them would recommend it to others.Areas of improvement include adding features that would calculate and validate the elapsed time since the sexual assault,adding explanations to some buttons,and providing training.Conclusions:Our findings highlight the value of using a mixed methods research design to conduct a usability and acceptability test.Nurses are more likely to adopt a new technology for their evidencebased practice when the technology is easy to use and useful and requires less time to find the right piece of guideline evidence.Individualized training needs to be designed based on users'characteristics.
基金Supported by the Scientific and Technological Innovation Project of China Academy of Chinese Medical Sciences:Design and Application of Mixed Method Research in Traditional Chinese Medicine(No.CI2021B003)Special Project of China Center for Evidence Based Traditional Chinese Medicine:Integrated Innovation and Application of Traditional Trial and Real-World Study of Chinese Medicine in Integrated Chinese and Western Medicine Setting(No.2020YJSZX-3)the Fundamental Research Funds for the Central Public Welfare Research Institutes:the Optimal Subject Setting and Design of Evidence-Based Research Implementation in the Area of Brain Diseases of Traditional Chinese Medicine(No.ZZ13-024-3)
文摘OBJECTIVE:To update the current characteristics about the scope and quality of mixed methods research(MMR)in complementary and alternative medicine(CAM)after nearly 10 years.METHODS:A 5-stage approach for conducting a scoping review was adopted.Articles published on the top 10 journals in CAM with the highest impact factor in 2020 were screened for MMR.Information of included articles were extracted,and then synthesized to illustrate the current state.Methodological quality was evaluated according to the Mixed Method Appraisal Tool(MMAT)2018 version.RESULTS:A total of 55(55/2991,2%)articles using mixed methods were retrieved,including 17 medical studies and 38 ethnobotanical studies.We performed an in-depth analysis on the 17 medical studies,which studied cancer,stress,pain,fatigue,exercises,mindfulness intervention,herbal medicine use,art and acupuncture.Thirteen pilot studies applied MMR to evaluate the feasibility of interventions or programs(13/17,76%);phenomenology was inferred as the most common philosophical assumptions(13/17,76%);the most applied type of MMR was convergent design(16/17,94%);integration often took place at integration(12/17,71%).Among the 16 eligible studies for quality appraisal,majority were rated as good(14/16,88%),whereas two studies were rated as poorly described.Primarily,a poor rating was due to incomplete reporting of data analysis and citations in qualitative components;lack of confounder controlling and the sampling strategy in quantitative components;poor description of integration and justification for mixed methods.Comparing with the previous review,fewer MMR were published in 2020 in CAM,but the proportion of studies that clearly reported MMR has increased by 4 times(4%→15%).CONCLUSION:CAM researchers need to realize the benefits that MMR can have on conducting further health care research.Our findings highlight that applying MMR will be helpful to understand the complex dynamics and interdisciplinary nature of complex intervention.In addition,addressing a standardized reporting criteria for MMR is recommended.
基金funded by the National Institute for Health Research (NIHR) Public Health Research Programme (13/90/18)supported by the Medical Research Council (Unit Program number MC_UU_12015/7)and was undertaken under the auspices of the Centre for Diet and Activity Research (CEDAR),a UKCRC Public Health Research Centre of Excellence+2 种基金Funding from the British Heart Foundation, Cancer Research UK,Economic and Social Research Council, Medical Research Council,National Institute for Health Research,and Wellcome Trust,under the auspices of the UK Clinical Research Collaboration,is gratefully acknowledged(087636/Z/08/ZES/G007462/1MR/K023187/1)
文摘Purpose'. To examine adolescent experiences and perspectives of the GoActive intervention (ISRCTN31583496) using mixed methods processevaluation to determine satisfaction with intervention components and interpret a*dolescents experiences of the intervention process in order toprovide insights for future intervention design.Methods'. Participants (n = 1542;13.2 土 0.4 years, mean 土 SD) provided questionnaire data at baseline (shyness, activity level) and post-intervention(intervention acceptability, satisfaction with components). Between-group differences (boys vs. girls and shy/inactive vs. others) weretested with linear regression models, accounting for school clustering. Data from 16 individual interviews (shy/inactive) and 11 focus groupswith 48 participants (mean = 4;range 2—7) were thematically coded. Qualitative and quantitative data were merged in an integrative mixedmethods convergence matrix, which denoted convergence and dissonance across datasets.Results'. Effect sizes for quantitative results were small and may not represent substantial between-group differences. Boys (vs. girls) preferredclass-based sessions (0 = 0.2, 95% confidence interval (CI): 0.1—0.3);qualitative data suggested that this was because boys preferred competition,which was supported quantitatively (0 = 0.2, 95%CI: 0.1-0.3). Shy/inactive students did not enjoy the competition (0 = -0.3, 95%CI:—0.5 to —0.1). Boys enjoyed trying new activities more (0 = 0.1, 95%CI: 0.1 -0.2);qualitative data indicated a desire to try new activities acrossall subgroups but identified barriers to choosing unfamiliar activities with self-imposed choice restriction leading to boredom. Qualitative datahighlighted critique of mentorship;adolescents liked the idea, but older mentors did not meet expectations.Conclusion. We interpreted adolescent perspectives of intervention components and implementation to provide insights into future complexinterventions aimed at increasing young people's physical activity in school-based settings. The intervention component mentorship was liked inprinciple, but implementation issues undesirably impacted satisfaction;competition was disliked by girls and shy/inactive students. The resultshighlight the importance of considering gender differences in preference of competition and extensive mentorship training.
基金Supported by NNSF(10601022,11061021)Supported by NSF of Inner Mongolia Au-tonomous Region(200607010106)Supported by SRP of Higher Schools of Inner Mongolia(NJ10006)
文摘H1-Galerkin mixed methods are proposed for viscoelasticity wave equation.Depending on the physical quantities of interest,two methods are discussed.The optimal error estimates and the proof of the existence and uniqueness of semidiscrete solutions are derived for problems in one space dimension.And the methods don＇t require the LBB condition.
基金the National Natural Science Foundation of China(No.50178916,No.19732020 and No.19872016)the National Key Basic lteseareh Special Foundation(No.G1999032805)+1 种基金the Special Funds for Major State Basic Researeh Projectsthe Foundation for University Key Teachers by the Ministry of Education of China
文摘A new algorithm for the solution of quadratic programming problemsis put forward in terms of the mixed energy theory and is furtherused for the incremental solution of elastic-plastic trussstructures. The method proposed is different from the traditionalone, for which the unknown variables are selected just in one classsuch as displacements or stresses. The present method selects thevariables in the mixed form with both displacement and stress. As themethod is established in the hybrid space, the information found inthe previous incremental step can be used for the solution of thepresent step, making the algorithm highly effi- cient in thenumerical solution process of quadratic programming problems. Theresults obtained in the exm- ples of the elastic-plastic solution ofthe truss structures verify what has been predicted in thetheoretical anal- ysis.
基金supported by the National Natural Science Foundation of China (No. 10601022)NSF ofInner Mongolia Autonomous Region of China (No. 200607010106)513 and Science Fund of InnerMongolia University for Distinguished Young Scholars (No. ND0702)
文摘A mixed time discontinuous space-time finite element scheme for secondorder convection diffusion problems is constructed and analyzed. Order of the equation is lowered by the mixed finite element method. The low order equation is discretized with a space-time finite element method, continuous in space but discontinuous in time. Stability, existence, uniqueness and convergence of the approximate solutions are proved. Numerical results are presented to illustrate efficiency of the proposed method.
