MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in supercapacitors.However,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene...MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in supercapacitors.However,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene until now,while the bimetallic and multimetallic MXene have received comparatively less attention.In this work,we demonstrate that the electronic structure of the Mo_(2)TiC_(2)T_(x) MXene could be regulated by fine-tuning the content of doped Nb atoms.The enhanced electron cloud density of surface–O termination and the electron spin of the Mo atoms in the Mo_(2)TiC_(2)T_(x) MXene,leads to the boost of electric double-layer capacitor(EDLC)and improvement of pseudocapacitance.As a consequence,the electrochemical performance of Nb-doped Mo_(2)TiC_(2)T_(x) MXene(Nb-0.3-MXene)demonstrates a capacitance of 398 F·cm^(−3),roughly doubling that of the pristine Mo_(2)TiC_(2)T_(x) MXene electrode at 197 F·cm^(−3) in the 3 M H_(2)SO_(4) electrolyte.At the same time,the Nb-0.3-MXene could even maintain a capacitance of 82.75% at 200 mV·s−1,with high cyclic stability for 19,000 cycles at 10 A·g−1.Additionally,Nb-0.3-MXene-based hybrid supercapacitors deliver a remarkable volumetric energy density of 48.1 W·h·L^(−1)at 230.7 W·L^(−1),and 34.4 W·h·L^(−1)at a high power density of 82.6 kW·L^(−1).There exists a balance between the volumetric capacitance and rate performance with different ratios of Nb atoms in the Nb-doped MXene due to the strong interaction between the Nb-doped MXene and the intercalated protons.Therefore,optimizing the electronic structure of MXene through heteroatom doping is of great potential for enhanced supercapacitor performance.展开更多
The purpose of this study is to investigate and quantify some possible sources of dispersion of 120 mm APFSDS tank ammunition both experimentally and numerically.This paper aims to point out the most influential sourc...The purpose of this study is to investigate and quantify some possible sources of dispersion of 120 mm APFSDS tank ammunition both experimentally and numerically.This paper aims to point out the most influential source during In-Bore Balloting Motion phase as well as in External Ballistics phase of the ammunition and quantifies its effect on dispersion.Data obtained from flight trials is critically analysed and parameters affecting dispersion such as initial yaw/pitch rates,yaw/pitch dampening,plane start angle,launch spin,clearance,centre of gravity shift,dynamic imbalance angle,cross wind,etc.are observed and,later on,studied in detail by extensive External Ballistics Monte Carlo(EBMC)simulation and Six Degree of Freedom(6-DOF)trajectory analysis.In Bore Balloting Motion simulation shows that reduction in residual spin by about 5%results in drastic56%reduction in first maximum yaw.A correlation between first maximum yaw and residual spin is observed.Results of data analysis are used in design modification for existing ammunition.Number of designs are evaluated numerically before freezing five designs for further soundings.These designs are critically assessed in terms of their comparative performance during In-bore travel&external ballistics phase.Results are validated by free flight trials for the finalised design.展开更多
When the rate of a symmetric second-order symmetric tensor is discussed,the spin of the principal axis is involved.This paper proposes a method to establish the basis-free expression of the spin in terms of tensor and...When the rate of a symmetric second-order symmetric tensor is discussed,the spin of the principal axis is involved.This paper proposes a method to establish the basis-free expression of the spin in terms of tensor and its rate by making use of the tensor function representation theorem.The proposed method is simple and the expression of the spin established is compact.To obtain the rate of the isotropic function of a second-order symmetric tensor,the fourth-order tangent tensor needs to be derived,which is the derivative of the tensor function to the second-order tensor.By decomposing the second-order symmetric tensor space into two orthogonal subspaces,the closed-form fourth-order tangent tensor is decomposed into two parts,which are linear mappings in these two orthogonal subspaces,respectively.These two linear mappings are derived in an extremely simple way.Finally,the method proposed in this paper is applied to obtain the expression of the relationship between material logarithmic strain rate and deformation rate.The whole process is simple and avoids tedious operations.展开更多
In the governing thought, I find an equivalence between the classical information in a quantum system and the integral of that system’s energy and time, specifically , in natural units. I solve this relationship in f...In the governing thought, I find an equivalence between the classical information in a quantum system and the integral of that system’s energy and time, specifically , in natural units. I solve this relationship in four ways: the first approach starts with the Schrodinger Equation and applies the Minkowski transformation;the second uses the Canonical commutation relation;the third through Gabor’s analysis of the time-frequency plane and Heisenberg’s uncertainty principle;and lastly by quantizing Brownian motion within the Bernoulli process and applying the Gaussian channel capacity. In support I give two examples of quantum systems that follow the governing thought: namely the Gaussian wave packet and the electron spin. I conclude with comments on the discretization of space and the information content of a degree of freedom.展开更多
Based on the general solution given to a kind of linear tensor equations,the spin of a symmetric tensor is derived in an invariant form.The result is applied to find the spins of the left and the tight stretch tensors...Based on the general solution given to a kind of linear tensor equations,the spin of a symmetric tensor is derived in an invariant form.The result is applied to find the spins of the left and the tight stretch tensors and the relation among different rotation rate tensors has been discussed.According to work conjugacy,the relations between Cauchy stress and the stresses conjugate to Hill's generalized strains are obtained.Particularly,the logarithmic strain,its time rate and the conjugate stress have been discussed in de- tail.These results are important in modeling the constitutive relations for finite deformations in continuum me- chanics.展开更多
The engineering of switchable materials with controllable stimuli-responsive multistability remains challenging in materials science.Herein,we present syntheses and structural and magnetic studies of a one-dimensional...The engineering of switchable materials with controllable stimuli-responsive multistability remains challenging in materials science.Herein,we present syntheses and structural and magnetic studies of a one-dimensional cobalt(Ⅱ)coordination polymer[(enbzp)Co(bpy)](ClO_(4))_(2)·-MeOH·H2O(1;enbzp=N,N′-(ethane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine,bpy=4,4′-bipyridine)and its desolvated analogue[(enbzp)Co(bpy)](ClO_(4))_(2)(2),obtained by reversible single-crystal-to-single-crystal(SCSC)transformation.展开更多
The hybrid optical pumping spin exchange relaxation free(HOPSERF)atomic co-magnetometers make ultrahigh sensitivity measurement of inertia achievable.The wall relaxation rate has a big effect on the polarization and f...The hybrid optical pumping spin exchange relaxation free(HOPSERF)atomic co-magnetometers make ultrahigh sensitivity measurement of inertia achievable.The wall relaxation rate has a big effect on the polarization and fundamental sensitivity for the co-magnetometer,but it is often neglected in the experiments.However,there is almost no work about the systematic analysis of the influence factors on the polarization and the fundamental sensitivity of the HOPSERF co-magnetometers.Here we systematically study the polarization and the fundamental sensitivity of 39K-85Rb-21Ne and 133Cs-85Rb-21Ne HOPSERF co-magnetometers with low polarization limit and the wall relaxation rate.The 21Ne number density,the power density and wavelength of pump beam will affect the polarization greatly by affecting the pumping rate of the pump beam.We obtain a general formula on the fundamental sensitivity of the HOPSERF co-magnetometers due to shot-noise and the fundamental sensitivity changes with multiple systemic parameters,where the suitable number density of buffer gas and quench gas make the fundamental sensitivity highest.The fundamental sensitivity 7.5355×10^-11 rad·s^-1·Hz^-1/2 of 133Cs-85Rb-21Ne co-magnetometer is higher than the ultimate theoretical sensitivity 2×10^-10 rad·s^-1·Hz^-1/2 of K-21Ne co-magnetometer.展开更多
基金supported by the National Natural Science Foundation of China(No.52272242)the Provisional Key Research and Development Program of Henan Province(No.231111240600)+1 种基金the Natural Science Foundation of Henan Province(No.242300421428)the Start-up Funding for Scientific Research of Zhengzhou University(No.32310221).
文摘MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in supercapacitors.However,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene until now,while the bimetallic and multimetallic MXene have received comparatively less attention.In this work,we demonstrate that the electronic structure of the Mo_(2)TiC_(2)T_(x) MXene could be regulated by fine-tuning the content of doped Nb atoms.The enhanced electron cloud density of surface–O termination and the electron spin of the Mo atoms in the Mo_(2)TiC_(2)T_(x) MXene,leads to the boost of electric double-layer capacitor(EDLC)and improvement of pseudocapacitance.As a consequence,the electrochemical performance of Nb-doped Mo_(2)TiC_(2)T_(x) MXene(Nb-0.3-MXene)demonstrates a capacitance of 398 F·cm^(−3),roughly doubling that of the pristine Mo_(2)TiC_(2)T_(x) MXene electrode at 197 F·cm^(−3) in the 3 M H_(2)SO_(4) electrolyte.At the same time,the Nb-0.3-MXene could even maintain a capacitance of 82.75% at 200 mV·s−1,with high cyclic stability for 19,000 cycles at 10 A·g−1.Additionally,Nb-0.3-MXene-based hybrid supercapacitors deliver a remarkable volumetric energy density of 48.1 W·h·L^(−1)at 230.7 W·L^(−1),and 34.4 W·h·L^(−1)at a high power density of 82.6 kW·L^(−1).There exists a balance between the volumetric capacitance and rate performance with different ratios of Nb atoms in the Nb-doped MXene due to the strong interaction between the Nb-doped MXene and the intercalated protons.Therefore,optimizing the electronic structure of MXene through heteroatom doping is of great potential for enhanced supercapacitor performance.
文摘The purpose of this study is to investigate and quantify some possible sources of dispersion of 120 mm APFSDS tank ammunition both experimentally and numerically.This paper aims to point out the most influential source during In-Bore Balloting Motion phase as well as in External Ballistics phase of the ammunition and quantifies its effect on dispersion.Data obtained from flight trials is critically analysed and parameters affecting dispersion such as initial yaw/pitch rates,yaw/pitch dampening,plane start angle,launch spin,clearance,centre of gravity shift,dynamic imbalance angle,cross wind,etc.are observed and,later on,studied in detail by extensive External Ballistics Monte Carlo(EBMC)simulation and Six Degree of Freedom(6-DOF)trajectory analysis.In Bore Balloting Motion simulation shows that reduction in residual spin by about 5%results in drastic56%reduction in first maximum yaw.A correlation between first maximum yaw and residual spin is observed.Results of data analysis are used in design modification for existing ammunition.Number of designs are evaluated numerically before freezing five designs for further soundings.These designs are critically assessed in terms of their comparative performance during In-bore travel&external ballistics phase.Results are validated by free flight trials for the finalised design.
文摘When the rate of a symmetric second-order symmetric tensor is discussed,the spin of the principal axis is involved.This paper proposes a method to establish the basis-free expression of the spin in terms of tensor and its rate by making use of the tensor function representation theorem.The proposed method is simple and the expression of the spin established is compact.To obtain the rate of the isotropic function of a second-order symmetric tensor,the fourth-order tangent tensor needs to be derived,which is the derivative of the tensor function to the second-order tensor.By decomposing the second-order symmetric tensor space into two orthogonal subspaces,the closed-form fourth-order tangent tensor is decomposed into two parts,which are linear mappings in these two orthogonal subspaces,respectively.These two linear mappings are derived in an extremely simple way.Finally,the method proposed in this paper is applied to obtain the expression of the relationship between material logarithmic strain rate and deformation rate.The whole process is simple and avoids tedious operations.
文摘In the governing thought, I find an equivalence between the classical information in a quantum system and the integral of that system’s energy and time, specifically , in natural units. I solve this relationship in four ways: the first approach starts with the Schrodinger Equation and applies the Minkowski transformation;the second uses the Canonical commutation relation;the third through Gabor’s analysis of the time-frequency plane and Heisenberg’s uncertainty principle;and lastly by quantizing Brownian motion within the Bernoulli process and applying the Gaussian channel capacity. In support I give two examples of quantum systems that follow the governing thought: namely the Gaussian wave packet and the electron spin. I conclude with comments on the discretization of space and the information content of a degree of freedom.
基金The project is supported by the National Natural Science Foundation of Chinathe Chinese Academy of Sciences(No.87-52)
文摘Based on the general solution given to a kind of linear tensor equations,the spin of a symmetric tensor is derived in an invariant form.The result is applied to find the spins of the left and the tight stretch tensors and the relation among different rotation rate tensors has been discussed.According to work conjugacy,the relations between Cauchy stress and the stresses conjugate to Hill's generalized strains are obtained.Particularly,the logarithmic strain,its time rate and the conjugate stress have been discussed in de- tail.These results are important in modeling the constitutive relations for finite deformations in continuum me- chanics.
基金supported by the Stable Support Plan Program of Shenzhen Natural Science Fund(no.20200925151834005)the National Natural Science Foundation of China(nos.21671095,21901108,and 22173043)。
文摘The engineering of switchable materials with controllable stimuli-responsive multistability remains challenging in materials science.Herein,we present syntheses and structural and magnetic studies of a one-dimensional cobalt(Ⅱ)coordination polymer[(enbzp)Co(bpy)](ClO_(4))_(2)·-MeOH·H2O(1;enbzp=N,N′-(ethane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine,bpy=4,4′-bipyridine)and its desolvated analogue[(enbzp)Co(bpy)](ClO_(4))_(2)(2),obtained by reversible single-crystal-to-single-crystal(SCSC)transformation.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFA0301500)the National Natural Science Foundation of China(Grant No.61835013)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB01020300 and XDB21030300)。
文摘The hybrid optical pumping spin exchange relaxation free(HOPSERF)atomic co-magnetometers make ultrahigh sensitivity measurement of inertia achievable.The wall relaxation rate has a big effect on the polarization and fundamental sensitivity for the co-magnetometer,but it is often neglected in the experiments.However,there is almost no work about the systematic analysis of the influence factors on the polarization and the fundamental sensitivity of the HOPSERF co-magnetometers.Here we systematically study the polarization and the fundamental sensitivity of 39K-85Rb-21Ne and 133Cs-85Rb-21Ne HOPSERF co-magnetometers with low polarization limit and the wall relaxation rate.The 21Ne number density,the power density and wavelength of pump beam will affect the polarization greatly by affecting the pumping rate of the pump beam.We obtain a general formula on the fundamental sensitivity of the HOPSERF co-magnetometers due to shot-noise and the fundamental sensitivity changes with multiple systemic parameters,where the suitable number density of buffer gas and quench gas make the fundamental sensitivity highest.The fundamental sensitivity 7.5355×10^-11 rad·s^-1·Hz^-1/2 of 133Cs-85Rb-21Ne co-magnetometer is higher than the ultimate theoretical sensitivity 2×10^-10 rad·s^-1·Hz^-1/2 of K-21Ne co-magnetometer.
