We fabricate a series of samples and OLEDs with organic multilayer quantum well structure, which consist of alternate PBD and Alqy Both PBD and Alq3 are electron-transporting materials, and PBD is used as potential ba...We fabricate a series of samples and OLEDs with organic multilayer quantum well structure, which consist of alternate PBD and Alqy Both PBD and Alq3 are electron-transporting materials, and PBD is used as potential barrier layer, while Alq3 is used as potential well layer and emitting layer. Compared with double-layer structure, the luminescent characteristics of organic samples and diodes with quantum well structure are investigated and the quantum well structure helps the energy transfer between well layer and barrier layer. The quantum well structure makes carriers disperse in the different well layers and then increases the number of excitons to enhance the efficiency of the recombination.展开更多
With the Breit interaction and quantum electrodynamics corrections considered, relativistic configuration interaction calculations have been carried out in the extended optimal level scheme using multi-configuration D...With the Breit interaction and quantum electrodynamics corrections considered, relativistic configuration interaction calculations have been carried out in the extended optimal level scheme using multi-configuration Dirac-Fock wave functions on the 204 energy levels and electric dipole transitions of Ar XIV. The results of electric dipole transitions are in good agreement with experiments. Among the energy levels calculated, the lowest 125 levels are in good agreement with available experimental and other theoretical ones, and the other 79 levels are new ones obtained by the present work. This wide range of atomic energy levels is useful in astrophysics and plasma physics.展开更多
On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) in pure phospholipid rnono...On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) in pure phospholipid rnonolayer at the air/water interface during compression are derived. The optimized conformations of phospholipids at absolute freedom state are simulated by Gaussian 98 software. Based on following assumptions: (1) the conformation energy change is mainly caused by the rotation of one special bond; (2) the atoms of glycerol near the water surface are active; (3) the rotation is motivated by hydrogen-bond action; (4) the rotation of bond is inertial, one simplified track of conformational change is suggested and the conformations of DPPC and DPPG at different states are determined by the plots of conformation energy change vs. dihedral angle. The thickness of the simulated phospholipid monolayer is consistent with published experimental result. According to molecular areas at different states, the molecular orientations in the compressing process are also developed.展开更多
Using a first-principle method, the electronic structures and the impurity formation energy of ZnO, ZnO (N), ZnO (N+B), and ZnO (2N+B) have been calculated, based on which the feasibility to obtain p-type ZnO ...Using a first-principle method, the electronic structures and the impurity formation energy of ZnO, ZnO (N), ZnO (N+B), and ZnO (2N+B) have been calculated, based on which the feasibility to obtain p-type ZnO & discussed. According to the results, when ZnO is single doped by N, the acceptor level is deep, and the formation energy is negative, so the ideal p-type ZnO can not be obtained by this way. On the contrary, when 2N+B are codoped into ZnO, the acceptor level becomes much lower, and the formation energy is positive, so it is a better way to obtain p-type ZnO.展开更多
Since there may exist dark matter particles ν and δ with mass - 10^-1 e V in the universe, the superstructures with a scale of 10^19 solar masses (large number A - 10^19) appeared during the era near and before th...Since there may exist dark matter particles ν and δ with mass - 10^-1 e V in the universe, the superstructures with a scale of 10^19 solar masses (large number A - 10^19) appeared during the era near and before the hydrogen recombination. Since there are superstructures in the universe, there may be no necessity for the existence of dark energy. For checking the superstructure in the universe by CMB anisotropy, we need to measure CMB angular power spectrum especially around ten degrees across the sky- in more details, While neutrino u is related to electroweak unification, the fourth stable elementary particle 6 may be related to strong-gravity unification, which suggests p + p^- → n + δ^- and that some new baryons appeared in the TeV region.展开更多
Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approac...Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approach to study interfacial mechanics of the 2D planar EEDs on the checkerboard buckling patterns of human skin.Energy variation method is proposed to determine a criterion whether EEDs laminate conformally onto the skin surface under undeformed and stretched cases.EEDs with low bending stiffness(thin,soft devices/backing layer),smooth and soft skin,and strong adhesion promote conformal contact.Furthermore,the adhesion energy at the EED/skin interface is measured by the homemade peeling experiment platform with different substrate thicknesses and areal coverages.The upper limit of the areal coverage for EED conformal contact with the skin is proposed with given EED/skin properties.Conformability of EEDs are validated by experiments with different substrate thickness,areal coverage and external loadings.It provides a design guideline for EED to conformally contact with the skin surface for more accurate biological signal monitoring.展开更多
Based on the magnetospheric kinetic theory, a model is developed to specify the flux of energetic electrons in the inner and middle magnetosphere. Under the assumption of adiabatic motion and isotropic particle distri...Based on the magnetospheric kinetic theory, a model is developed to specify the flux of energetic electrons in the inner and middle magnetosphere. Under the assumption of adiabatic motion and isotropic particle distribution maintained by pitch-angle scattering, the model calculates the electron flux by following bounce-averaged electric field, gradient, and curvature drift in the time dependent electric and magnetic field, meanwhile it counts the electron loss caused by pitch angle scattering. Using the model, the clectron flux distribution during a magnetic storm was calculated and compared with the observation data from the geosynchronous orbit. It is shown that the model can successfully reproduce most of the major electron flux enhancements observed at the geosynchronous orbit and generally tracks the satellite data well. The rms errors of the modeled logarithm of flux are between 0.5-1.0.展开更多
The variation of the flux of energetic electrons in the magnetosphere has been proven to be strongly related to the solar wind speed. Observations of GEO orbit show that the flux of low-energy electrons is not only mo...The variation of the flux of energetic electrons in the magnetosphere has been proven to be strongly related to the solar wind speed. Observations of GEO orbit show that the flux of low-energy electrons is not only modulated by the solar wind speed, but, if a time delay is added, is also positively correlated to the flux of high-energy electrons. This feature provides a possible method to forecast the flux of high-energy electrons in GEO orbit. In this study, the correlations of the fluxes between the high-energy electrons and low-middle-energy electrons obtained at different L values and in different orbits are investigated to develop the application of this feature. Based on the analysis of long–term data observed by NOAA POES and GOES, the correlations between the fluxes of high-energy electrons and low–middle–energy electrons are good enough at different L values and in different orbits in quiet time, but this correlation is strongly affected by CME–driven geomagnetic storms.展开更多
As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggi...As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggish diffusion kinetics and poor cycling stability in most cathode materials,restricting their further applications.In this work,we demonstrated a novel K+-intercalated Mn/Ni-based layered oxide material(K0.7Mn0.7Ni0.3O2,denoted as KMNO)with stabilized and enlarged diffusion channels for high energy density SIBs.A spontaneous ion exchange behavior in forming K0.1Na0.7Mn0.7Ni0.3O2between the KMNO electrode and the sodium ion electrolyte was clearly revealed by in situ X-ray diffraction and ex situ inductively coupled plasma analysis.The interlayer space varied from 6.90 to 5.76?,larger than that of Na0.7Mn0.7Ni0.3O2(5.63?).The enlarged ionic diffusion channels can effectively increase the ionic diffusion coefficient and simultaneously provide more K+storage sites in the product framework.As a proof-of-concept application,the SIBs with the as-prepared KMNO as a cathode display a high reversible discharge capacity(161.8 mA h g-1at0.1 A g-1),high energy density(459 W h kg-1)and superior rate capability of 71.1 mA h g-1at 5 A g-1.Our work demonstrates that the K+pre-intercalation strategy endows the layered metal oxides with excellent sodium storage performance,which provides new directions for the design of cathode materials for various batteries.展开更多
We report the experimental and theoretical investigation of the complete valence shell binding energy spectra and momentum profiles of naphthalene (C 10 H 8),using our high resolution electron momentum spectrometer,at...We report the experimental and theoretical investigation of the complete valence shell binding energy spectra and momentum profiles of naphthalene (C 10 H 8),using our high resolution electron momentum spectrometer,at impact energies of 1500 eV and 600 eV.The observed momentum profiles were compared with the Hartree-Fock (HF) and density functional theory (DFT) calculations,and the binding energy spectrum was compared with the Outer valence Green's function (OVGF) calculations.The impact energy dependent discrepancy between observed momentum distributions and calculations under the plane wave impulse approximation was ascribed to the distorted wave effects.展开更多
The electronic structure, atomic geometry and energetic properties of ceramic nanomultilayer have been systematically studied with first principles density functional theory calculations based on the generalized gradi...The electronic structure, atomic geometry and energetic properties of ceramic nanomultilayer have been systematically studied with first principles density functional theory calculations based on the generalized gradient approximations. It is found that the interface structure and adhesion, which determine the mechanical and thermal properties, are sensitive to the surface mor- phology. We also provide an analysis of adhesion of ZrO2/A1203 interface as a function of thickness of each layer. With the in- crease of ZrO2 thickness, both covalence and ionicity of the interfacial bonds are enhanced, which results in more strongly coupled interfaces while the ionic interaction decreases for thicker Al2O3 layers, which results in weakly coupled interfaces. A first-principles calculation method has been proposed to design nanomultilayer materials to achieve the demanded adhesion.展开更多
基金This work was Supported by "973" National Key Basic ResearchFoundation of China (No. 2003CB314707)National Natural Sci-ence Foundation of China (No. 60576016 ,10374001, and No.10434030).
文摘We fabricate a series of samples and OLEDs with organic multilayer quantum well structure, which consist of alternate PBD and Alqy Both PBD and Alq3 are electron-transporting materials, and PBD is used as potential barrier layer, while Alq3 is used as potential well layer and emitting layer. Compared with double-layer structure, the luminescent characteristics of organic samples and diodes with quantum well structure are investigated and the quantum well structure helps the energy transfer between well layer and barrier layer. The quantum well structure makes carriers disperse in the different well layers and then increases the number of excitons to enhance the efficiency of the recombination.
文摘With the Breit interaction and quantum electrodynamics corrections considered, relativistic configuration interaction calculations have been carried out in the extended optimal level scheme using multi-configuration Dirac-Fock wave functions on the 204 energy levels and electric dipole transitions of Ar XIV. The results of electric dipole transitions are in good agreement with experiments. Among the energy levels calculated, the lowest 125 levels are in good agreement with available experimental and other theoretical ones, and the other 79 levels are new ones obtained by the present work. This wide range of atomic energy levels is useful in astrophysics and plasma physics.
基金Supported by the National Natural Science Foundation of China (20876047).
文摘On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) in pure phospholipid rnonolayer at the air/water interface during compression are derived. The optimized conformations of phospholipids at absolute freedom state are simulated by Gaussian 98 software. Based on following assumptions: (1) the conformation energy change is mainly caused by the rotation of one special bond; (2) the atoms of glycerol near the water surface are active; (3) the rotation is motivated by hydrogen-bond action; (4) the rotation of bond is inertial, one simplified track of conformational change is suggested and the conformations of DPPC and DPPG at different states are determined by the plots of conformation energy change vs. dihedral angle. The thickness of the simulated phospholipid monolayer is consistent with published experimental result. According to molecular areas at different states, the molecular orientations in the compressing process are also developed.
基金Supported by the Foundation for the Excellent Youth Scholars of Anhui Education Office under Grant No.2009SQRZ097ZDthe Foundation of Anhui Province Education Bureau under Grant No.KJ2008B262 the Foundation of Anhui University of Architecture under Grant No.20070601
文摘Using a first-principle method, the electronic structures and the impurity formation energy of ZnO, ZnO (N), ZnO (N+B), and ZnO (2N+B) have been calculated, based on which the feasibility to obtain p-type ZnO & discussed. According to the results, when ZnO is single doped by N, the acceptor level is deep, and the formation energy is negative, so the ideal p-type ZnO can not be obtained by this way. On the contrary, when 2N+B are codoped into ZnO, the acceptor level becomes much lower, and the formation energy is positive, so it is a better way to obtain p-type ZnO.
文摘Since there may exist dark matter particles ν and δ with mass - 10^-1 e V in the universe, the superstructures with a scale of 10^19 solar masses (large number A - 10^19) appeared during the era near and before the hydrogen recombination. Since there are superstructures in the universe, there may be no necessity for the existence of dark energy. For checking the superstructure in the universe by CMB anisotropy, we need to measure CMB angular power spectrum especially around ten degrees across the sky- in more details, While neutrino u is related to electroweak unification, the fourth stable elementary particle 6 may be related to strong-gravity unification, which suggests p + p^- → n + δ^- and that some new baryons appeared in the TeV region.
文摘Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approach to study interfacial mechanics of the 2D planar EEDs on the checkerboard buckling patterns of human skin.Energy variation method is proposed to determine a criterion whether EEDs laminate conformally onto the skin surface under undeformed and stretched cases.EEDs with low bending stiffness(thin,soft devices/backing layer),smooth and soft skin,and strong adhesion promote conformal contact.Furthermore,the adhesion energy at the EED/skin interface is measured by the homemade peeling experiment platform with different substrate thicknesses and areal coverages.The upper limit of the areal coverage for EED conformal contact with the skin is proposed with given EED/skin properties.Conformability of EEDs are validated by experiments with different substrate thickness,areal coverage and external loadings.It provides a design guideline for EED to conformally contact with the skin surface for more accurate biological signal monitoring.
基金supported by the National Natural Science Foundation of China(Grant No.40704032)
文摘Based on the magnetospheric kinetic theory, a model is developed to specify the flux of energetic electrons in the inner and middle magnetosphere. Under the assumption of adiabatic motion and isotropic particle distribution maintained by pitch-angle scattering, the model calculates the electron flux by following bounce-averaged electric field, gradient, and curvature drift in the time dependent electric and magnetic field, meanwhile it counts the electron loss caused by pitch angle scattering. Using the model, the clectron flux distribution during a magnetic storm was calculated and compared with the observation data from the geosynchronous orbit. It is shown that the model can successfully reproduce most of the major electron flux enhancements observed at the geosynchronous orbit and generally tracks the satellite data well. The rms errors of the modeled logarithm of flux are between 0.5-1.0.
基金supported by the National Natural Science Foundation of China(Grant Nos.41374167,41074117&41374166)
文摘The variation of the flux of energetic electrons in the magnetosphere has been proven to be strongly related to the solar wind speed. Observations of GEO orbit show that the flux of low-energy electrons is not only modulated by the solar wind speed, but, if a time delay is added, is also positively correlated to the flux of high-energy electrons. This feature provides a possible method to forecast the flux of high-energy electrons in GEO orbit. In this study, the correlations of the fluxes between the high-energy electrons and low-middle-energy electrons obtained at different L values and in different orbits are investigated to develop the application of this feature. Based on the analysis of long–term data observed by NOAA POES and GOES, the correlations between the fluxes of high-energy electrons and low–middle–energy electrons are good enough at different L values and in different orbits in quiet time, but this correlation is strongly affected by CME–driven geomagnetic storms.
基金supported by the National Natural Science Foundation of China(51872218 and 51832004)the National Key R&D Program of China(2016YFA0202603)the Fundamental Research Funds for the Central Universities(WUT:2017III009)。
文摘As promising,low-cost alternatives of lithiumion batteries for large-scale electric energy storage,sodiumion batteries(SIBs)have been studied by many researchers.However,the relatively large size of Na+leads to sluggish diffusion kinetics and poor cycling stability in most cathode materials,restricting their further applications.In this work,we demonstrated a novel K+-intercalated Mn/Ni-based layered oxide material(K0.7Mn0.7Ni0.3O2,denoted as KMNO)with stabilized and enlarged diffusion channels for high energy density SIBs.A spontaneous ion exchange behavior in forming K0.1Na0.7Mn0.7Ni0.3O2between the KMNO electrode and the sodium ion electrolyte was clearly revealed by in situ X-ray diffraction and ex situ inductively coupled plasma analysis.The interlayer space varied from 6.90 to 5.76?,larger than that of Na0.7Mn0.7Ni0.3O2(5.63?).The enlarged ionic diffusion channels can effectively increase the ionic diffusion coefficient and simultaneously provide more K+storage sites in the product framework.As a proof-of-concept application,the SIBs with the as-prepared KMNO as a cathode display a high reversible discharge capacity(161.8 mA h g-1at0.1 A g-1),high energy density(459 W h kg-1)and superior rate capability of 71.1 mA h g-1at 5 A g-1.Our work demonstrates that the K+pre-intercalation strategy endows the layered metal oxides with excellent sodium storage performance,which provides new directions for the design of cathode materials for various batteries.
基金supported by the National Natural Science Foundation of China (Grants Nos. 11074144,10874097 and 10704046)Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20070003146)
文摘We report the experimental and theoretical investigation of the complete valence shell binding energy spectra and momentum profiles of naphthalene (C 10 H 8),using our high resolution electron momentum spectrometer,at impact energies of 1500 eV and 600 eV.The observed momentum profiles were compared with the Hartree-Fock (HF) and density functional theory (DFT) calculations,and the binding energy spectrum was compared with the Outer valence Green's function (OVGF) calculations.The impact energy dependent discrepancy between observed momentum distributions and calculations under the plane wave impulse approximation was ascribed to the distorted wave effects.
文摘The electronic structure, atomic geometry and energetic properties of ceramic nanomultilayer have been systematically studied with first principles density functional theory calculations based on the generalized gradient approximations. It is found that the interface structure and adhesion, which determine the mechanical and thermal properties, are sensitive to the surface mor- phology. We also provide an analysis of adhesion of ZrO2/A1203 interface as a function of thickness of each layer. With the in- crease of ZrO2 thickness, both covalence and ionicity of the interfacial bonds are enhanced, which results in more strongly coupled interfaces while the ionic interaction decreases for thicker Al2O3 layers, which results in weakly coupled interfaces. A first-principles calculation method has been proposed to design nanomultilayer materials to achieve the demanded adhesion.