Field-assisted electrocatalytic reactions are demonstrated to be sufficient strategies in enhancing the electrocatalyst activities for oxygen evolution reaction(OER).Here,we report the in-situ magnetic field enhanced ...Field-assisted electrocatalytic reactions are demonstrated to be sufficient strategies in enhancing the electrocatalyst activities for oxygen evolution reaction(OER).Here,we report the in-situ magnetic field enhanced electrocatalytic activity in ferromagnetic FeCo_(2)O_(4)nanofibers.Our results demonstrate that the overpotential of FeCo_(2)O_(4)nanofibers at 10 mA cm^(-2)shows a left-shift of 40 mV for the OER by applying an external magnetic field,and no obvious change has been observed in the non-ferromagnetic-order Co3O4nanofibers.Calculation results indicate that there are more overlaps between the density of states for Co3d and O 2p by applying an external magnetic field.Accordingly,the spin hybridization of 3d-2p and the kinetics of spin charge transfer are optimized in ferromagnetic FeCo_(2)O_(4),which can promote the adsorption of oxygen-intermediates and electron transfer,significantly improving its electrocatalytic efficiency.What’s more,the maximum power density of the FeCo_(2)O_(4)nanofibers based Zn-air battery(ZAB)increases from 97.3 mW cm^(-2)to 108.2 mW cm^(-2)by applying an external magnetic field,providing a new idea for the application of magnetic cathode electrocatalysts in ZABs.展开更多
内源性类洋地黄物质(Endogenousdigitalis like substances,EDLS)是存在于人和哺乳动物体内的一种具有强大的强心、利尿和收缩血管作用的物质。它与外源性洋地黄一样,可以抑制Na^+—K^+—ATP酶,竞争性抑制~3H—哇巴因与受体结合,可与某...内源性类洋地黄物质(Endogenousdigitalis like substances,EDLS)是存在于人和哺乳动物体内的一种具有强大的强心、利尿和收缩血管作用的物质。它与外源性洋地黄一样,可以抑制Na^+—K^+—ATP酶,竞争性抑制~3H—哇巴因与受体结合,可与某些强心甙抗体产生交叉反应,在免疫学方面显示出类似洋地黄的抗原特性,因此可用RIA方法检测。EDLS主要存在于人和哺乳动物的下丘脑、心脏、肾上腺等组织,对机体内环境恒定的维持起重要作用。文献报告,妊娠妇女外周血EDLS浓度显著升高,脐血EDLS浓度显著高于产妇外周血,产妇外周血EDLS浓度在产后24小时迅速下降。展开更多
We calculated the crustal stress field using the composite focal mechanism method based on the P-wave initial motion polarity data of the Tengchong volcanic area from January 2011 to April 2019 obtained from the Bulle...We calculated the crustal stress field using the composite focal mechanism method based on the P-wave initial motion polarity data of the Tengchong volcanic area from January 2011 to April 2019 obtained from the Bulletin of Seismological Observations of Chinese stations.The magnitude range of earthquakes used in this study is 0–4,and their magnitudes are mainly approximately 1.0.To investigate the infl uence of the source location on the stress fi eld and obtain reliable stress fi elds of the study area,we applied the double-diff erence algorithm to relocate the seismic events,obtaining more accurate and reliable relative positions of seismic events with a clearer seismic belt.On the basis of relocation results,the study on the stress fi eld along the fault zone was conducted,and the infl uence of seismic event position on the stress fi eld was analyzed.Results show that,fi rst,the current stress regime in the shallow crust of the Tengchong volcanic area is strike-slip faulting,the orientation of the principal compressive stress axis is NE–SW,the orientation of the principal extension stress axis is SE–NW,the principal compressive and extension stress axes are nearly horizontal,and the dip angle of intermediate principal stress axis is relatively large.This reflects that the volcanic and seismic activities in the Tengchong volcanic area are mainly controlled by the collision and squeezing eff ect of the Indian–Eurasian plate.It also refl ects that the current tensile action caused by deep magma activity has little infl uence on the shallow crustal stress field.Second,the stress field along fault zones reveals that there exist local stress fi elds,such as the thrust stress regime at the strike-slip fault terminal area,which is consistent with the compressional area at the intersection of conjugate strike-slip faults indicated by previous study.Third,the stress fi eld results are consistent,regardless of using the original location in the bulletin or the relocated location,indicating that the infl uence of the event location error can be neglected when there are suffi cient data and refl ecting the stability of the composite focal mechanism method.The findings can serve as a reference for investigating geological structure movement,seismic activities,and volcanic activities in the Tengchong volcanic area.展开更多
Magnetic field gradient tensor technique provides abundant data for delicate inversion of subsurface magnetic susceptibility distribution. Large scale magnetic data inversion imaging requires high speed and accuracy f...Magnetic field gradient tensor technique provides abundant data for delicate inversion of subsurface magnetic susceptibility distribution. Large scale magnetic data inversion imaging requires high speed and accuracy for forward modeling. For arbitrarily distributed susceptibility data on an undulated surface, we propose a fast 3D forward modeling method in the wavenumber domain based on(1) the wavenumber-domain expression of the prism combination model and the Gauss–FFT algorithm and(2) cubic spline interpolation. We apply the proposed 3D forward modeling method to synthetic data and use weighting coefficients in the wavenumber domain to improve the modeling for multiple observation surfaces, and also demonstrate the accuracy and efficiency of the proposed method.展开更多
Gravity and magnetic exploration areas are usually irregular,and there is some data defi ciency.Missing data must be interpolated before the vertical derivative conversion in the wavenumber domain.Meanwhile,for improv...Gravity and magnetic exploration areas are usually irregular,and there is some data defi ciency.Missing data must be interpolated before the vertical derivative conversion in the wavenumber domain.Meanwhile,for improved processing precision,the data need to be edge-padded to the length required by the fast Fourier transform algorithm.For conventional vertical derivative conversion of potential fi eld data(PFD),only vertical derivative conversion is considered,or interpolation,border padding,and vertical derivative conversion are executed independently.In this paper,these three steps are considered uniformly,and a vertical derivative conversion method for irregular-range PFD based on an improved projection onto convex sets method is proposed.The cutoff wavenumber of the filter used in the proposed method is determined by fractal model fi tting of the radial average power spectrum(RAPS)of the potential fi eld.Theoretical gravity models and real aeromagnetic data show the following:(1)The fitting of the RAPS with a fractal model can separate useful signals and noise reasonably.(2)The proposed iterative method has a clear physical sense,and its interpolation,border padding error,and running time are much smaller than those of the conventional kriging and minimum curvature methods.展开更多
The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration b...The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications.However,the downward continuation of potential fields is a typical linear inverse problem that is ill-posed.Generalized minimal residuals(GMRES)is an eff ective solution to ill-posed inverse problems,but it is unstable under the condition wherein the GMRES is directly applied in the calculation process.Moreover,the long-term behavior of its iterative computation is a disordered,divergent result.Therefore,to obtain stable solutions,GMRES is applied to solve the normal equations of the downward continuation of potential fields;it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient,thus strengthening the stability conditions of the equations of residual minimization.Finally,the stable downward continuation of the potential fields method is proposed.As indicated by the theoretical data and the measured testing data,the method proposed in this paper has the advantages of high-precision and excellent stability.Furthermore,compared with the Tikhonov iteration method,the proposed method avoids the need to choose regularization parameters.展开更多
In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multip...In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multipole force eld in enhanced sampling simula-tions of single-channel gramicidin A(gA)and double-channel gA systems and investigated its reliability in characterizing ion-transport properties of the gA ion channel under dimer-ization.The inuence of gA dimerization on the permeation of potassium and sodium ions through the channel was described in terms of conductance,di usion coeffcient,and free energy pro le.Results from the polarizable force eld simulations show that the conductance of potassium and sodium ions passing through the single-and double-channel agrees well with experimental values.Further data analysis reveals that the molecular mechanism of protein dimerization a ects the ion-transport properties of gA channels,i.e.,protein dimer-ization accelerates the permeation of potassium and sodium ions passing through the double-channel by adjusting the environment around gA protein(the distribution of phospholipid head groups,ions outside the channel,and bulk water),rather than directly adjusting the conformation of gA protein.展开更多
基金financially supported by the Natural Science Foundation(NSF) of China(91963201 and 12174163)the Creation of Science and Technology of Northwest Normal University,China(NWNU-LKQN2020-22)。
文摘Field-assisted electrocatalytic reactions are demonstrated to be sufficient strategies in enhancing the electrocatalyst activities for oxygen evolution reaction(OER).Here,we report the in-situ magnetic field enhanced electrocatalytic activity in ferromagnetic FeCo_(2)O_(4)nanofibers.Our results demonstrate that the overpotential of FeCo_(2)O_(4)nanofibers at 10 mA cm^(-2)shows a left-shift of 40 mV for the OER by applying an external magnetic field,and no obvious change has been observed in the non-ferromagnetic-order Co3O4nanofibers.Calculation results indicate that there are more overlaps between the density of states for Co3d and O 2p by applying an external magnetic field.Accordingly,the spin hybridization of 3d-2p and the kinetics of spin charge transfer are optimized in ferromagnetic FeCo_(2)O_(4),which can promote the adsorption of oxygen-intermediates and electron transfer,significantly improving its electrocatalytic efficiency.What’s more,the maximum power density of the FeCo_(2)O_(4)nanofibers based Zn-air battery(ZAB)increases from 97.3 mW cm^(-2)to 108.2 mW cm^(-2)by applying an external magnetic field,providing a new idea for the application of magnetic cathode electrocatalysts in ZABs.
文摘内源性类洋地黄物质(Endogenousdigitalis like substances,EDLS)是存在于人和哺乳动物体内的一种具有强大的强心、利尿和收缩血管作用的物质。它与外源性洋地黄一样,可以抑制Na^+—K^+—ATP酶,竞争性抑制~3H—哇巴因与受体结合,可与某些强心甙抗体产生交叉反应,在免疫学方面显示出类似洋地黄的抗原特性,因此可用RIA方法检测。EDLS主要存在于人和哺乳动物的下丘脑、心脏、肾上腺等组织,对机体内环境恒定的维持起重要作用。文献报告,妊娠妇女外周血EDLS浓度显著升高,脐血EDLS浓度显著高于产妇外周血,产妇外周血EDLS浓度在产后24小时迅速下降。
基金the National Scholarship Fundthe National Natural Science Foundation of China(Nos.41704053,42174074,41674055)the East China University of Technology Research Foundation for Advanced Talents(ECUT)(DHBK2019084)for financial support。
文摘We calculated the crustal stress field using the composite focal mechanism method based on the P-wave initial motion polarity data of the Tengchong volcanic area from January 2011 to April 2019 obtained from the Bulletin of Seismological Observations of Chinese stations.The magnitude range of earthquakes used in this study is 0–4,and their magnitudes are mainly approximately 1.0.To investigate the infl uence of the source location on the stress fi eld and obtain reliable stress fi elds of the study area,we applied the double-diff erence algorithm to relocate the seismic events,obtaining more accurate and reliable relative positions of seismic events with a clearer seismic belt.On the basis of relocation results,the study on the stress fi eld along the fault zone was conducted,and the infl uence of seismic event position on the stress fi eld was analyzed.Results show that,fi rst,the current stress regime in the shallow crust of the Tengchong volcanic area is strike-slip faulting,the orientation of the principal compressive stress axis is NE–SW,the orientation of the principal extension stress axis is SE–NW,the principal compressive and extension stress axes are nearly horizontal,and the dip angle of intermediate principal stress axis is relatively large.This reflects that the volcanic and seismic activities in the Tengchong volcanic area are mainly controlled by the collision and squeezing eff ect of the Indian–Eurasian plate.It also refl ects that the current tensile action caused by deep magma activity has little infl uence on the shallow crustal stress field.Second,the stress field along fault zones reveals that there exist local stress fi elds,such as the thrust stress regime at the strike-slip fault terminal area,which is consistent with the compressional area at the intersection of conjugate strike-slip faults indicated by previous study.Third,the stress fi eld results are consistent,regardless of using the original location in the bulletin or the relocated location,indicating that the infl uence of the event location error can be neglected when there are suffi cient data and refl ecting the stability of the composite focal mechanism method.The findings can serve as a reference for investigating geological structure movement,seismic activities,and volcanic activities in the Tengchong volcanic area.
基金supported by the National Special Plan for the 13th Five-Year Plan of China(No.2017YFC0602204-10)Independent Exploration of the Innovation Project for Graduate Students at Central South University(No.2017zzts176)+3 种基金National Natural Science Foundation of China(Nos.41574127,41404106,and 41674075)Postdoctoral Fund Projects of China(No.2017M622608)National Key R&D Program of China(No.2018YFC0603602)Natural Science Youth Fund Project of the Hunan Province,China(No.2018JJ3642)
文摘Magnetic field gradient tensor technique provides abundant data for delicate inversion of subsurface magnetic susceptibility distribution. Large scale magnetic data inversion imaging requires high speed and accuracy for forward modeling. For arbitrarily distributed susceptibility data on an undulated surface, we propose a fast 3D forward modeling method in the wavenumber domain based on(1) the wavenumber-domain expression of the prism combination model and the Gauss–FFT algorithm and(2) cubic spline interpolation. We apply the proposed 3D forward modeling method to synthetic data and use weighting coefficients in the wavenumber domain to improve the modeling for multiple observation surfaces, and also demonstrate the accuracy and efficiency of the proposed method.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41804136, 41774156, 61773389)the Young Talent Fund of University Association for Science and Technology in Shaanxi,China (Grant No.20180702)
文摘Gravity and magnetic exploration areas are usually irregular,and there is some data defi ciency.Missing data must be interpolated before the vertical derivative conversion in the wavenumber domain.Meanwhile,for improved processing precision,the data need to be edge-padded to the length required by the fast Fourier transform algorithm.For conventional vertical derivative conversion of potential fi eld data(PFD),only vertical derivative conversion is considered,or interpolation,border padding,and vertical derivative conversion are executed independently.In this paper,these three steps are considered uniformly,and a vertical derivative conversion method for irregular-range PFD based on an improved projection onto convex sets method is proposed.The cutoff wavenumber of the filter used in the proposed method is determined by fractal model fi tting of the radial average power spectrum(RAPS)of the potential fi eld.Theoretical gravity models and real aeromagnetic data show the following:(1)The fitting of the RAPS with a fractal model can separate useful signals and noise reasonably.(2)The proposed iterative method has a clear physical sense,and its interpolation,border padding error,and running time are much smaller than those of the conventional kriging and minimum curvature methods.
基金This research is supported by the National Key Research and Development Program of China under Grant No.2018YFC1505401the Key Research and Development Projects of the Sichuan Science and Technology Department under Grant Nos.2019YFG0460,2020YFG0303,and 2021YJ0031+1 种基金the Technology Research and Development Program of China Railway Group Limited under Grant No.CZ01-Key Point-05the Fundamental Research Funds for the Central Universities under Grant No.2682021GF019.
文摘The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications.However,the downward continuation of potential fields is a typical linear inverse problem that is ill-posed.Generalized minimal residuals(GMRES)is an eff ective solution to ill-posed inverse problems,but it is unstable under the condition wherein the GMRES is directly applied in the calculation process.Moreover,the long-term behavior of its iterative computation is a disordered,divergent result.Therefore,to obtain stable solutions,GMRES is applied to solve the normal equations of the downward continuation of potential fields;it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient,thus strengthening the stability conditions of the equations of residual minimization.Finally,the stable downward continuation of the potential fields method is proposed.As indicated by the theoretical data and the measured testing data,the method proposed in this paper has the advantages of high-precision and excellent stability.Furthermore,compared with the Tikhonov iteration method,the proposed method avoids the need to choose regularization parameters.
基金This work is supported by the National Natural Sci-ence Foundation of China(No.21933010).
文摘In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multipole force eld in enhanced sampling simula-tions of single-channel gramicidin A(gA)and double-channel gA systems and investigated its reliability in characterizing ion-transport properties of the gA ion channel under dimer-ization.The inuence of gA dimerization on the permeation of potassium and sodium ions through the channel was described in terms of conductance,di usion coeffcient,and free energy pro le.Results from the polarizable force eld simulations show that the conductance of potassium and sodium ions passing through the single-and double-channel agrees well with experimental values.Further data analysis reveals that the molecular mechanism of protein dimerization a ects the ion-transport properties of gA channels,i.e.,protein dimer-ization accelerates the permeation of potassium and sodium ions passing through the double-channel by adjusting the environment around gA protein(the distribution of phospholipid head groups,ions outside the channel,and bulk water),rather than directly adjusting the conformation of gA protein.
