In past decades,ABX_(3) halide perovskites have attracted great interest in solar cells due to excellent opto-electronic properties,such as high carrier mobility.However,instability and toxicity are obstacles on the c...In past decades,ABX_(3) halide perovskites have attracted great interest in solar cells due to excellent opto-electronic properties,such as high carrier mobility.However,instability and toxicity are obstacles on the commercial route for perovskites.Many studies have turned to exploring A_(2) BX_(6) and A_(3) B_(2) X_(9) for better stability.Unfortunately,the carrier mobilities of these two types are inferior to ABX_(3),lower by an order of magnitude.Furthermore,the mobility of ABX_(3) is distributed over a large range of 1.78-4500 cm^(2) V^(−1) s^(−1) in experiments,which contributes to another diversity of mobilities.In this paper,we aim at reveal-ing the physical origin of the above-mentioned diversities by theoretical studies on CsBX_(3),Cs_(2) BX_(6),and Cs_(3) B_(2) X_(9)(B=Sn,Pb,Sb,Bi,X=Br,Cl).The difference in group velocities is the major reason responsible for the variation in these types.The unique three-dimensional connected conductive network of CsBX_(3) determines its large group velocity.As for carrier scattering,ionized impurity scattering dominates at low carrier and high ionized impurity concentrations.Detailed analysis reveals that band degeneracy is strongly related to the impurity scattering rate,while dielectric constant is almost immune.Our study provides a better understanding of the relationship between electronic structures and mobilities for po-tential applications in photovoltaics.展开更多
An improved Reduced-Order Model(ROM)is proposed based on a flow-solution preprocessing operation and a fast sampling strategy to efficiently and accurately predict ionized hypersonic flows.This ROM is generated in low...An improved Reduced-Order Model(ROM)is proposed based on a flow-solution preprocessing operation and a fast sampling strategy to efficiently and accurately predict ionized hypersonic flows.This ROM is generated in low-dimensional space by performing the Proper Orthogonal Decomposition(POD)on snapshots and is coupled with the Radial Basis Function(RBF)to achieve fast prediction speed.However,due to the disparate scales in the ionized flow field,the conventional ROM usually generates spurious negative errors.Here,this issue is addressed by performing flow-solution preprocessing in logarithmic space to improve the conventional ROM.Then,extra orthogonal polynomials are introduced in the RBF interpolation to achieve additional improvement of the prediction accuracy.In addition,to construct high-efficiency snapshots,a trajectory-constrained adaptive sampling strategy based on convex hull optimization is developed.To evaluate the performance of the proposed fast prediction method,two hypersonic vehicles with classic configurations,i.e.a wave-rider and a reentry capsule,are used to validate the proposed method.Both two cases show that the proposed fast prediction method has high accuracy near the vehicle surface and the free-stream region where the flow field is smooth.Compared with the conventional ROM prediction,the prediction results are significantly improved by the proposed method around the discontinuities,e.g.the shock wave and the ionized layer.As a result,the proposed fast prediction method reduces the error of the conventional ROM by at least 45%,with a speedup of approximately 2.0×105compared to the Computational Fluid Dynamic(CFD)simulations.These test cases demonstrate that the method developed here is efficient and accurate for predicting ionized hypersonic flows.展开更多
An experimental platform of a pulse detonation engine(PDE) was established to study the effect of different K_2 CO_3 ionized seed mass contents on the detonation process.The pressure and ion concentration were detecte...An experimental platform of a pulse detonation engine(PDE) was established to study the effect of different K_2 CO_3 ionized seed mass contents on the detonation process.The pressure and ion concentration were detected in the detonation process of the PDE with different contents of ionized seeds.The initiation process of the PDE at different ignition frequencies was studied.The results show that the gas conductivity in the detonation process increased by adding ionized seeds to the PDE tube,and the conductivity increased with the increase in ionized seed mass content.With the increase in ionized seed mass content,the range of the conductivity decreased.The PDE was successfully ignited and formed a stable detonation wave at ignition frequencies of 5 Hz and 10 Hz,and the peak pressure of the stable detonation with the ignition frequency of 5 Hz was 17% higher than that with an ignition frequency of 10 Hz.The detonation wave intensity was weake ned and dege nerated to a shock wave that propagated in the tube without the fuel filled at the ignition frequency of 20 Hz.展开更多
The mechanism of variable color luminescence in ionized gases is pre-sented from the view point of luminescence kinetics. On the basis of the simplifiedmodels for excitation radiation, it is studied that the selectiv...The mechanism of variable color luminescence in ionized gases is pre-sented from the view point of luminescence kinetics. On the basis of the simplifiedmodels for excitation radiation, it is studied that the selective excitation preduedby controlling the展开更多
Dependence of decamethylcyclopentasiloxane （DMCPS） organosilicon dissociation on ionized energy in the energy range of 25 eV to 70 eV is investigated by using a quadrupole mass spectrometry. At the ionized energy be...Dependence of decamethylcyclopentasiloxane （DMCPS） organosilicon dissociation on ionized energy in the energy range of 25 eV to 70 eV is investigated by using a quadrupole mass spectrometry. At the ionized energy below 55 eV, the dissociation of DMCPS is dominant. As the ionized energy is above 55 eV, the DMCPS dissociation achieves the maximum cross section, while the fragments from the DMCPS dissociation can further dissociate, which leads to a different ingredient of fragments. At the lower ionized energy of 25 eV, the main fragments are SiOC2H＋, SiCH＋, Si＋, O＋ and CH＋ ions, which shows an important effect on the SiCOH low-k film deposition.展开更多
Based on the framework of the effective-mass approximation, the ionized acceptor bound exciton （A- X） binding energy and the emission wavelength are investigated for a cylindrical wurtzite （WZ） GaN/A1x Ga1-xN quan...Based on the framework of the effective-mass approximation, the ionized acceptor bound exciton （A- X） binding energy and the emission wavelength are investigated for a cylindrical wurtzite （WZ） GaN/A1x Ga1-xN quantum dot （QD） with finite potential barriers by means of a variational method. Numerical results show that the binding energy and the emission wavelength highly depend on the QD size, the position of the ionized acceptor and the Al composition x of the barrier material AIxGal-xN. The binding energy and the emission wavelength are larger when the acceptor is located in the vicinity of the left interface of the QD. In particular, the binding energy of （ A-, X） complex is insensitive to the dot height when the acceptor is located at the left boundary of the QD. The ionized acceptor bound exciton binding energy and the emission wavelength are both increased if Al composition x is increased.展开更多
As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectrosco...As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectroscopy(IFS)with a resolution of 1–2 kpc for104galaxies in the local universe during its six-year operation from July 2014 through August 2020.It is crucial to reliably measure the physical properties of the different components in each spectrum before one can use the data for any scientific study.In the past years we have made lots of efforts to develop a novel technique of full spectral fitting,which estimates a model-independent dust attenuation curve from each spectrum,thus allowing us to break the degeneracy between dust attenuation and stellar population properties when fitting the spectrum with stellar population synthesis models.We have applied our technique to the final data release of Ma NGA,and obtained measurements of stellar population properties and emission line parameters,as well as the kinematics and dust attenuation of both stellar and ionized gas components.In this paper we describe our technique and the content and format of our data products.The whole dataset is publicly available in Science Data Bank with the link https://doi.org/10.57760/sciencedb.j00113.00088.展开更多
The purpose of the present work is to present a full-wave analysis of scattering from the weakly ionized plasma in the plane geometry. We have yielded an approximate solution in an analytic form to the electromagnetic...The purpose of the present work is to present a full-wave analysis of scattering from the weakly ionized plasma in the plane geometry. We have yielded an approximate solution in an analytic form to the electromagnetic wave scattering from the weakly ionized plasma. In the normal and oblique incidence, the analytic solution works well, as compared with the exact solution and the solution based on the Wenzell-Kramers-Brillouin-Jeffreys (WKBJ) approximation to the uniform density profile.展开更多
Objective:To evaluate the effect of serum ionized calcium levels on the prognosis of severe sepsis patients.Methods:This retrospective cross-sectional study included sepsis patients who were hospitalized in an intensi...Objective:To evaluate the effect of serum ionized calcium levels on the prognosis of severe sepsis patients.Methods:This retrospective cross-sectional study included sepsis patients who were hospitalized in an intensive care unit between January 2011 and December 2014.The demographic and baseline data of the patients who died and survived were compared.The cutoff value of ionized calcium for in-hospital mortality was determined by the receiver operating characteristics curve(ROC).In-hospital mortalities and the survival rates were compared between patients with different ionized calcium levels.Besides,the risk factor of in-hospital mortality was determined.Results:This study included 145 patients with 113 patients who died in the hospital.The patients who died had significantly lower ionized calcium levels(U=2.25,P=0.034).A cut-off value of 0.93 mmol/L of ionized calcium was determined by the ROC curve.The patients with ionized calcium>0.93 mmol/L showed a significantly lower morality(χ2=9.90,P=0.002)and higher survival rate than with≤0.93 mmol/L(log rank=6.20,P=0.010).Multivariate Cox regression revealed that ionized calcium≤0.93 mmol/L was a risk factor of in-hospital mortality.Conclusions:Ionized calcium level≤0.93 mmol/L was an independent predictor of in-hospital mortality of severe sepsis.展开更多
The collision frequencies of electron-neutral-particle in weakly ionized complex plasmas with the non-Maxwellian velocity distributions are studied.The average collision frequencies of electron-neutral-particle in pla...The collision frequencies of electron-neutral-particle in weakly ionized complex plasmas with the non-Maxwellian velocity distributions are studied.The average collision frequencies of electron-neutral-particle in plasmas are accurately derived.We find that these collision frequencies are significantly dependent on the power-law spectral indices of non-Maxwellian distribution functions and so they are generally different from the collision frequencies in plasmas with a Maxwellian velocity distribution,which will affect the transport properties of the charged particles in plasmas.Numerically analyses are made to show the roles of the spectral indices in the average collision frequencies respectively.展开更多
It is represented the review about the effect of low doses of ionized radiation on different types of biological objects (Japanese quail embryos, Aspergillus niger, Spirostomum ambiguum Ehrbg., mezenchim stem cells of...It is represented the review about the effect of low doses of ionized radiation on different types of biological objects (Japanese quail embryos, Aspergillus niger, Spirostomum ambiguum Ehrbg., mezenchim stem cells of mice bone brain, dry seeds of the highest plants, blood lymphocytes of pilots and cosmonauts) and water medium. In model experiments under the chronic ionized radiation in doses comparable with the doses of ionized radiation inside the orbital space stations and during the flight in interplanetary space was shown alike with morphological deviations (Japanese quail embryos, Aspergillus niger), the phenomenon of radiation hormezis (Aspergillus niger, mezenchim stem cells), the increasing of the germination of seeds, the decreasing of spontaneous motion activity of spirostoms and DNA damage, chromosome aberrations and the increased radio-sensitivity to adding radiation load in blood lymphocytes. These data testified the fact that the definite factor of ionized radiation effect is the changing of water medium state. Thus under the interplanetary cosmic flight and long stay on the orbit in the region of magnetosphere the studying kinds of radiation first effected on the water medium of organism as a result morpho-functional structures were changed.展开更多
Study of radiation properties of mismatched microstrip termination is carried out in warm ionized electron plasma medium. Linearised hydrodynamic theory coupled with vector wave technique is used to investigate radiat...Study of radiation properties of mismatched microstrip termination is carried out in warm ionized electron plasma medium. Linearised hydrodynamic theory coupled with vector wave technique is used to investigate radiation patterns and radiated power of a microstrip mismatched termination in one component electron plasma media for different plasma to source frequencies .These properties are used to compare the performance of an open circuit discontinuity with those of matched microstrip termination. Matched terminations are found more suitable for applications at higher frequencies than an open circuit discontinuity in the plasma medium though in free space they are less suitable.展开更多
Experimental and theoretical studies of the radial distribution function of the electron temperature (RDFT) in a low-density plasma and weakly ionized gas for the abnormal glow region are presented. Experimentally, th...Experimental and theoretical studies of the radial distribution function of the electron temperature (RDFT) in a low-density plasma and weakly ionized gas for the abnormal glow region are presented. Experimentally, the electron temperatures and densities are measured by a Langmuir probe moved radially from the center to the edge of the cathode electrode for helium gas at different pressures in the low-pressure glow discharge. The comparison of the final experimental data for the radial distribution of electron temperatures and densities for different low pressures ranging from 0.2 to 1.2 torr, with the final proved equation of RDFT confirms that the electron temperatures decrease with increasing product of radial distance and gas pressures, showing a radial decrement dependence of the electron temperature from the center to the edge of the electrode. This is attributed to the increase of the number of electron-atom collisions at higher gas pressures and consequently of the rate of ionization. For the axial distance (L) from the tip of the probe to cathode electrode and the cathode electrode radius (R), a theoretical and experimental comparison for the two conditions L R and L > R, for both cases the produced plasma temperatures decrease and densities increase. It is concluded that the RDFT accurately shows a dramatic decrease for L R by 60% less than RDFT values for L > R similar as for conditions of magnetized and unmagnetized effect for DC plasma. This means that the rate of plasma loss by diffusion decreased for L R, agrees well with the applied of magnetic field展开更多
A theoretical methodology for thermochemical non-equilibrium flow combing with the HLLC(Harten-Lax-van Leer Contact) scheme was applied to study the hypersonic thermochemical non-equilibrium environment of an entry co...A theoretical methodology for thermochemical non-equilibrium flow combing with the HLLC(Harten-Lax-van Leer Contact) scheme was applied to study the hypersonic thermochemical non-equilibrium environment of an entry configuration in ionized flow. A two-temperature controlling model was utilized and the Gupta’s 11 species(N 2, O2, NO, O, N, NO+, N+2, O+2, N+, O+, e)thermochemical non-equilibrium model was taken. Firstly, numerical calculations of hypersonic thermochemical non-equilibrium environments for different aerodynamic shapes were carried out to verify the reliability of the method above. Then, the method was used to research the effects of ionization and wall catalysis on the hypersonic thermochemical non-equilibrium environment of the entry configuration in ionized flow. The shock stand-off distance can be reduced by thermochemical reactions but doesn’t continue to decrease significantly when ionization occurs. The shock stand-off distance calculated by the 11 species model is 4.2% smaller than that calculated by the 5 species(N2, O2, NO, O, N) thermochemical non-equilibrium model without considering ionization.Ionization reduces wall heat flux but increases wall pressure a little. The effect of ionization on aerothermal loads is greater than that of aerodynamic loads. The thermochemical reactions of electrons and ions catalyzed at the wall increase wall heat flux significantly but make a small change in wall pressure. The maximum wall heat flux obtained by only considering the electrons and ions catalyzed at the partially catalytic wall condition is 11.8% less than that calculated at the supercatalytic wall condition.展开更多
Above-threshold ionizations of rare gas atoms excited by polarized femtosecond laser pulses are investigated.The photoelectron momentum spectra are obtained applying the strong-field approximation(SFA) theory.It is fo...Above-threshold ionizations of rare gas atoms excited by polarized femtosecond laser pulses are investigated.The photoelectron momentum spectra are obtained applying the strong-field approximation(SFA) theory.It is found that,distribution of the emitted photoelectrons varies with different polarizations of laser pulses.We have interpreted the relationship between the observed distribution and the laser polarization taking advantage of tunneling ionization theory and simple-man model.The polarization sensitivity indicates that one can easily manipulate the photoelectron distribution by controlling the polarization of the exciting pulse.展开更多
The emergence of high-temperature superconductivity in hydrogen-rich compounds has opened up promising avenues for investigating unique hydrogen motifs that exhibit exceptional superconducting properties.Nevertheless,...The emergence of high-temperature superconductivity in hydrogen-rich compounds has opened up promising avenues for investigating unique hydrogen motifs that exhibit exceptional superconducting properties.Nevertheless,the requirement for extremely high synthesis pressures poses significant barriers to experimentally probing potential physical properties.Here,we have designed a structure wherein NH_(3)tetrahedra are intercalated into the body-centered cubic lattice of Yb,resulting in the formation of Yb(NH_(3))_(4).Our first-principles calculations reveal that metallic behavior emerges from the ionization of sp^(3)-hybridized s-bonds in NH_(3),which is enabled by electron transfer from ytterbium orbitals to NH_(3)anti-bonding s-orbitals.A distinctive feature of this structure is the Fermi surface nesting,which leads to optical phonon softening and consequently enhances electron-phonon coupling.The subsequent density-functional theory(DFT)calculations demonstrate that this I-43m phase of Yb(NH_(3))4 exhibits a superconducting critical temperature(T_(c))of 17.32 K under a modest pressure of 10 GPa.Our investigation presents perspectives on achieving phonon-mediated superconductivity at relatively low pressures,thereby opening up extensive possibilities for the attainment of high-temperature superconductivity in hydrogen-based superconducting systems with specific ionized molecular groups.展开更多
Meteor Burst Communication(MBC),a niche yet revolutionary wireless communication paradigm,exploits the transient ionized trails generated by meteors ablating in Earth’s atmosphere to enable sporadic yet resilient lon...Meteor Burst Communication(MBC),a niche yet revolutionary wireless communication paradigm,exploits the transient ionized trails generated by meteors ablating in Earth’s atmosphere to enable sporadic yet resilient long-distance radio links.Known for its exceptional resilience,robustness,and sustained connectivity,MBC holds significant promise for applications in emergency communications,remote area connectivity,military/defense systems,and environmental monitoring.However,the scientific exploration and application of MBC have long been highly challenging.In particular,under the combined influence of multiple physical field factors,the channel experiences superimposed multiple random fading effects,exhibiting bursty,highly time-varying,and strongly random characteristics.This persistent technical challenge has resulted in the absence of a practical statistical channel model for MBC to date.展开更多
In this paper,a 3D upstream finite element method is developed to analyze the ionized electric field around the UHVDC transmission lines including the building near it.The ionized electric field around the building is...In this paper,a 3D upstream finite element method is developed to analyze the ionized electric field around the UHVDC transmission lines including the building near it.The ionized electric field around the building is reduced due to the shielding effect of the building and the shielding distance is about three times its height.The ionized electric field including the human body model on the building and away from the building is also taken into account.The ionized electric field distortion ratio of the human body model is discussed in this paper.The distortion ratios for the positions on the building are less than those on the ground.展开更多
Herpes zoster （HZ） is an acute virus infectious disease mainly affecting middle-aged and elderly people. The morbidity rates of HZ in the age group of 50-59 years and 60-69 years are, respectively, 46 and 69 （per y...Herpes zoster （HZ） is an acute virus infectious disease mainly affecting middle-aged and elderly people. The morbidity rates of HZ in the age group of 50-59 years and 60-69 years are, respectively, 46 and 69 （per year, per 10,000 people）. The age groups of 70-79 years and 80-89 years have a much higher rate of 95 and 109 （per year, per 10,000 people）, respectively.展开更多
When evaluating the electromagnetic environment of high voltage direct current(HVDC)powers lines,a fundamental factor to consider is the ionized field at ground level.China’s rapid industrialization and urbanization ...When evaluating the electromagnetic environment of high voltage direct current(HVDC)powers lines,a fundamental factor to consider is the ionized field at ground level.China’s rapid industrialization and urbanization has led to haze pollution episodes.Ions generated by the corona discharge on the surface of HVDC power lines can adhere to haze particles,giving rise to variations in space charge density,which then impact the ionized field.In this paper,the charging and motion characteristics of the dielectric particle are investigated.The saturation charge amount of the particle and its contribution to the charge density are calculated in the spherical coordinates using the governing equations of the electric field.The terminal setting velocity is calculated based on the Stokes flow of particles in the gravitational and electrical fields.The mobility of the charged particle is also analyzed.This paper will serve as a valuable reference for the modeling and calculation of the ionized field of HVDC transmission lines,with the presence of dielectric particles.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFB3502200)the National Natural Science Foundation of China(Nos.52172216 and 92163212)+1 种基金support from the Shanghai Engi-neering Research Center for Integrated Circuits and Advanced Dis-play Materialssupported by Shanghai Techni-cal Service Center of Science and Engineering Computing,Shanghai University and Hefei Advanced Computing Center.
文摘In past decades,ABX_(3) halide perovskites have attracted great interest in solar cells due to excellent opto-electronic properties,such as high carrier mobility.However,instability and toxicity are obstacles on the commercial route for perovskites.Many studies have turned to exploring A_(2) BX_(6) and A_(3) B_(2) X_(9) for better stability.Unfortunately,the carrier mobilities of these two types are inferior to ABX_(3),lower by an order of magnitude.Furthermore,the mobility of ABX_(3) is distributed over a large range of 1.78-4500 cm^(2) V^(−1) s^(−1) in experiments,which contributes to another diversity of mobilities.In this paper,we aim at reveal-ing the physical origin of the above-mentioned diversities by theoretical studies on CsBX_(3),Cs_(2) BX_(6),and Cs_(3) B_(2) X_(9)(B=Sn,Pb,Sb,Bi,X=Br,Cl).The difference in group velocities is the major reason responsible for the variation in these types.The unique three-dimensional connected conductive network of CsBX_(3) determines its large group velocity.As for carrier scattering,ionized impurity scattering dominates at low carrier and high ionized impurity concentrations.Detailed analysis reveals that band degeneracy is strongly related to the impurity scattering rate,while dielectric constant is almost immune.Our study provides a better understanding of the relationship between electronic structures and mobilities for po-tential applications in photovoltaics.
基金supported by the National Natural Science Foundation of China(Nos.11902271 and 91952203)the Fundamental Research Funds for the Central Universities of China(No.G2019KY05102)111 project on“Aircraft Complex Flows and the Control”of China(No.B17037)。
文摘An improved Reduced-Order Model(ROM)is proposed based on a flow-solution preprocessing operation and a fast sampling strategy to efficiently and accurately predict ionized hypersonic flows.This ROM is generated in low-dimensional space by performing the Proper Orthogonal Decomposition(POD)on snapshots and is coupled with the Radial Basis Function(RBF)to achieve fast prediction speed.However,due to the disparate scales in the ionized flow field,the conventional ROM usually generates spurious negative errors.Here,this issue is addressed by performing flow-solution preprocessing in logarithmic space to improve the conventional ROM.Then,extra orthogonal polynomials are introduced in the RBF interpolation to achieve additional improvement of the prediction accuracy.In addition,to construct high-efficiency snapshots,a trajectory-constrained adaptive sampling strategy based on convex hull optimization is developed.To evaluate the performance of the proposed fast prediction method,two hypersonic vehicles with classic configurations,i.e.a wave-rider and a reentry capsule,are used to validate the proposed method.Both two cases show that the proposed fast prediction method has high accuracy near the vehicle surface and the free-stream region where the flow field is smooth.Compared with the conventional ROM prediction,the prediction results are significantly improved by the proposed method around the discontinuities,e.g.the shock wave and the ionized layer.As a result,the proposed fast prediction method reduces the error of the conventional ROM by at least 45%,with a speedup of approximately 2.0×105compared to the Computational Fluid Dynamic(CFD)simulations.These test cases demonstrate that the method developed here is efficient and accurate for predicting ionized hypersonic flows.
基金supported by the National Natural Science Foundation of China(No.11802039,No.51605046)the Jiangsu Natural Science Foundation of China(No.BK20160406)。
文摘An experimental platform of a pulse detonation engine(PDE) was established to study the effect of different K_2 CO_3 ionized seed mass contents on the detonation process.The pressure and ion concentration were detected in the detonation process of the PDE with different contents of ionized seeds.The initiation process of the PDE at different ignition frequencies was studied.The results show that the gas conductivity in the detonation process increased by adding ionized seeds to the PDE tube,and the conductivity increased with the increase in ionized seed mass content.With the increase in ionized seed mass content,the range of the conductivity decreased.The PDE was successfully ignited and formed a stable detonation wave at ignition frequencies of 5 Hz and 10 Hz,and the peak pressure of the stable detonation with the ignition frequency of 5 Hz was 17% higher than that with an ignition frequency of 10 Hz.The detonation wave intensity was weake ned and dege nerated to a shock wave that propagated in the tube without the fuel filled at the ignition frequency of 20 Hz.
文摘The mechanism of variable color luminescence in ionized gases is pre-sented from the view point of luminescence kinetics. On the basis of the simplifiedmodels for excitation radiation, it is studied that the selective excitation preduedby controlling the
文摘Dependence of decamethylcyclopentasiloxane （DMCPS） organosilicon dissociation on ionized energy in the energy range of 25 eV to 70 eV is investigated by using a quadrupole mass spectrometry. At the ionized energy below 55 eV, the dissociation of DMCPS is dominant. As the ionized energy is above 55 eV, the DMCPS dissociation achieves the maximum cross section, while the fragments from the DMCPS dissociation can further dissociate, which leads to a different ingredient of fragments. At the lower ionized energy of 25 eV, the main fragments are SiOC2H＋, SiCH＋, Si＋, O＋ and CH＋ ions, which shows an important effect on the SiCOH low-k film deposition.
基金Supported by Technology Projects of the Education Bureau of Fujian Province umder Grant No. JK2009038
文摘Based on the framework of the effective-mass approximation, the ionized acceptor bound exciton （A- X） binding energy and the emission wavelength are investigated for a cylindrical wurtzite （WZ） GaN/A1x Ga1-xN quantum dot （QD） with finite potential barriers by means of a variational method. Numerical results show that the binding energy and the emission wavelength highly depend on the QD size, the position of the ionized acceptor and the Al composition x of the barrier material AIxGal-xN. The binding energy and the emission wavelength are larger when the acceptor is located in the vicinity of the left interface of the QD. In particular, the binding energy of （ A-, X） complex is insensitive to the dot height when the acceptor is located at the left boundary of the QD. The ionized acceptor bound exciton binding energy and the emission wavelength are both increased if Al composition x is increased.
基金the National Key R&D Program of China(Grant No.2018YFA0404502)the National Natural Science Foundation of China(Grant Nos.11821303,11733002,11973030,11673015,11733004,11761131004,and 11761141012).
文摘As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectroscopy(IFS)with a resolution of 1–2 kpc for104galaxies in the local universe during its six-year operation from July 2014 through August 2020.It is crucial to reliably measure the physical properties of the different components in each spectrum before one can use the data for any scientific study.In the past years we have made lots of efforts to develop a novel technique of full spectral fitting,which estimates a model-independent dust attenuation curve from each spectrum,thus allowing us to break the degeneracy between dust attenuation and stellar population properties when fitting the spectrum with stellar population synthesis models.We have applied our technique to the final data release of Ma NGA,and obtained measurements of stellar population properties and emission line parameters,as well as the kinematics and dust attenuation of both stellar and ionized gas components.In this paper we describe our technique and the content and format of our data products.The whole dataset is publicly available in Science Data Bank with the link https://doi.org/10.57760/sciencedb.j00113.00088.
文摘The purpose of the present work is to present a full-wave analysis of scattering from the weakly ionized plasma in the plane geometry. We have yielded an approximate solution in an analytic form to the electromagnetic wave scattering from the weakly ionized plasma. In the normal and oblique incidence, the analytic solution works well, as compared with the exact solution and the solution based on the Wenzell-Kramers-Brillouin-Jeffreys (WKBJ) approximation to the uniform density profile.
文摘Objective:To evaluate the effect of serum ionized calcium levels on the prognosis of severe sepsis patients.Methods:This retrospective cross-sectional study included sepsis patients who were hospitalized in an intensive care unit between January 2011 and December 2014.The demographic and baseline data of the patients who died and survived were compared.The cutoff value of ionized calcium for in-hospital mortality was determined by the receiver operating characteristics curve(ROC).In-hospital mortalities and the survival rates were compared between patients with different ionized calcium levels.Besides,the risk factor of in-hospital mortality was determined.Results:This study included 145 patients with 113 patients who died in the hospital.The patients who died had significantly lower ionized calcium levels(U=2.25,P=0.034).A cut-off value of 0.93 mmol/L of ionized calcium was determined by the ROC curve.The patients with ionized calcium>0.93 mmol/L showed a significantly lower morality(χ2=9.90,P=0.002)and higher survival rate than with≤0.93 mmol/L(log rank=6.20,P=0.010).Multivariate Cox regression revealed that ionized calcium≤0.93 mmol/L was a risk factor of in-hospital mortality.Conclusions:Ionized calcium level≤0.93 mmol/L was an independent predictor of in-hospital mortality of severe sepsis.
基金supported by the National Natural science foundation of China under Grant No.11775156.
文摘The collision frequencies of electron-neutral-particle in weakly ionized complex plasmas with the non-Maxwellian velocity distributions are studied.The average collision frequencies of electron-neutral-particle in plasmas are accurately derived.We find that these collision frequencies are significantly dependent on the power-law spectral indices of non-Maxwellian distribution functions and so they are generally different from the collision frequencies in plasmas with a Maxwellian velocity distribution,which will affect the transport properties of the charged particles in plasmas.Numerically analyses are made to show the roles of the spectral indices in the average collision frequencies respectively.
文摘It is represented the review about the effect of low doses of ionized radiation on different types of biological objects (Japanese quail embryos, Aspergillus niger, Spirostomum ambiguum Ehrbg., mezenchim stem cells of mice bone brain, dry seeds of the highest plants, blood lymphocytes of pilots and cosmonauts) and water medium. In model experiments under the chronic ionized radiation in doses comparable with the doses of ionized radiation inside the orbital space stations and during the flight in interplanetary space was shown alike with morphological deviations (Japanese quail embryos, Aspergillus niger), the phenomenon of radiation hormezis (Aspergillus niger, mezenchim stem cells), the increasing of the germination of seeds, the decreasing of spontaneous motion activity of spirostoms and DNA damage, chromosome aberrations and the increased radio-sensitivity to adding radiation load in blood lymphocytes. These data testified the fact that the definite factor of ionized radiation effect is the changing of water medium state. Thus under the interplanetary cosmic flight and long stay on the orbit in the region of magnetosphere the studying kinds of radiation first effected on the water medium of organism as a result morpho-functional structures were changed.
文摘Study of radiation properties of mismatched microstrip termination is carried out in warm ionized electron plasma medium. Linearised hydrodynamic theory coupled with vector wave technique is used to investigate radiation patterns and radiated power of a microstrip mismatched termination in one component electron plasma media for different plasma to source frequencies .These properties are used to compare the performance of an open circuit discontinuity with those of matched microstrip termination. Matched terminations are found more suitable for applications at higher frequencies than an open circuit discontinuity in the plasma medium though in free space they are less suitable.
文摘Experimental and theoretical studies of the radial distribution function of the electron temperature (RDFT) in a low-density plasma and weakly ionized gas for the abnormal glow region are presented. Experimentally, the electron temperatures and densities are measured by a Langmuir probe moved radially from the center to the edge of the cathode electrode for helium gas at different pressures in the low-pressure glow discharge. The comparison of the final experimental data for the radial distribution of electron temperatures and densities for different low pressures ranging from 0.2 to 1.2 torr, with the final proved equation of RDFT confirms that the electron temperatures decrease with increasing product of radial distance and gas pressures, showing a radial decrement dependence of the electron temperature from the center to the edge of the electrode. This is attributed to the increase of the number of electron-atom collisions at higher gas pressures and consequently of the rate of ionization. For the axial distance (L) from the tip of the probe to cathode electrode and the cathode electrode radius (R), a theoretical and experimental comparison for the two conditions L R and L > R, for both cases the produced plasma temperatures decrease and densities increase. It is concluded that the RDFT accurately shows a dramatic decrease for L R by 60% less than RDFT values for L > R similar as for conditions of magnetized and unmagnetized effect for DC plasma. This means that the rate of plasma loss by diffusion decreased for L R, agrees well with the applied of magnetic field
文摘A theoretical methodology for thermochemical non-equilibrium flow combing with the HLLC(Harten-Lax-van Leer Contact) scheme was applied to study the hypersonic thermochemical non-equilibrium environment of an entry configuration in ionized flow. A two-temperature controlling model was utilized and the Gupta’s 11 species(N 2, O2, NO, O, N, NO+, N+2, O+2, N+, O+, e)thermochemical non-equilibrium model was taken. Firstly, numerical calculations of hypersonic thermochemical non-equilibrium environments for different aerodynamic shapes were carried out to verify the reliability of the method above. Then, the method was used to research the effects of ionization and wall catalysis on the hypersonic thermochemical non-equilibrium environment of the entry configuration in ionized flow. The shock stand-off distance can be reduced by thermochemical reactions but doesn’t continue to decrease significantly when ionization occurs. The shock stand-off distance calculated by the 11 species model is 4.2% smaller than that calculated by the 5 species(N2, O2, NO, O, N) thermochemical non-equilibrium model without considering ionization.Ionization reduces wall heat flux but increases wall pressure a little. The effect of ionization on aerothermal loads is greater than that of aerodynamic loads. The thermochemical reactions of electrons and ions catalyzed at the wall increase wall heat flux significantly but make a small change in wall pressure. The maximum wall heat flux obtained by only considering the electrons and ions catalyzed at the partially catalytic wall condition is 11.8% less than that calculated at the supercatalytic wall condition.
基金Supported by the National Natural Science Foundation of China under Grant No. 11104210
文摘Above-threshold ionizations of rare gas atoms excited by polarized femtosecond laser pulses are investigated.The photoelectron momentum spectra are obtained applying the strong-field approximation(SFA) theory.It is found that,distribution of the emitted photoelectrons varies with different polarizations of laser pulses.We have interpreted the relationship between the observed distribution and the laser polarization taking advantage of tunneling ionization theory and simple-man model.The polarization sensitivity indicates that one can easily manipulate the photoelectron distribution by controlling the polarization of the exciting pulse.
基金work was supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406200 and 2022YFA1405500)the National Natural Science Foundation of China(Grant Nos.12304021 and 52072188)+4 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ23A040004)Program for Science and Technology Innovation Team in Zhejiang(Grant No.2021R01004)the Natural Science Foundation of Ningbo(Grant No.2022J091)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT 15R23)Parts of calculations were performed at the Supercomputer Center of Ningbo University.
文摘The emergence of high-temperature superconductivity in hydrogen-rich compounds has opened up promising avenues for investigating unique hydrogen motifs that exhibit exceptional superconducting properties.Nevertheless,the requirement for extremely high synthesis pressures poses significant barriers to experimentally probing potential physical properties.Here,we have designed a structure wherein NH_(3)tetrahedra are intercalated into the body-centered cubic lattice of Yb,resulting in the formation of Yb(NH_(3))_(4).Our first-principles calculations reveal that metallic behavior emerges from the ionization of sp^(3)-hybridized s-bonds in NH_(3),which is enabled by electron transfer from ytterbium orbitals to NH_(3)anti-bonding s-orbitals.A distinctive feature of this structure is the Fermi surface nesting,which leads to optical phonon softening and consequently enhances electron-phonon coupling.The subsequent density-functional theory(DFT)calculations demonstrate that this I-43m phase of Yb(NH_(3))4 exhibits a superconducting critical temperature(T_(c))of 17.32 K under a modest pressure of 10 GPa.Our investigation presents perspectives on achieving phonon-mediated superconductivity at relatively low pressures,thereby opening up extensive possibilities for the attainment of high-temperature superconductivity in hydrogen-based superconducting systems with specific ionized molecular groups.
文摘Meteor Burst Communication(MBC),a niche yet revolutionary wireless communication paradigm,exploits the transient ionized trails generated by meteors ablating in Earth’s atmosphere to enable sporadic yet resilient long-distance radio links.Known for its exceptional resilience,robustness,and sustained connectivity,MBC holds significant promise for applications in emergency communications,remote area connectivity,military/defense systems,and environmental monitoring.However,the scientific exploration and application of MBC have long been highly challenging.In particular,under the combined influence of multiple physical field factors,the channel experiences superimposed multiple random fading effects,exhibiting bursty,highly time-varying,and strongly random characteristics.This persistent technical challenge has resulted in the absence of a practical statistical channel model for MBC to date.
基金supported by the Key Project of the National Natural Science Foundation of China(Grant No.51037001)the National Basic Research Program of China("973"Program)(Grant No.2011CB209401)
文摘In this paper,a 3D upstream finite element method is developed to analyze the ionized electric field around the UHVDC transmission lines including the building near it.The ionized electric field around the building is reduced due to the shielding effect of the building and the shielding distance is about three times its height.The ionized electric field including the human body model on the building and away from the building is also taken into account.The ionized electric field distortion ratio of the human body model is discussed in this paper.The distortion ratios for the positions on the building are less than those on the ground.
文摘Herpes zoster （HZ） is an acute virus infectious disease mainly affecting middle-aged and elderly people. The morbidity rates of HZ in the age group of 50-59 years and 60-69 years are, respectively, 46 and 69 （per year, per 10,000 people）. The age groups of 70-79 years and 80-89 years have a much higher rate of 95 and 109 （per year, per 10,000 people）, respectively.
基金supported in part by the Science and Technology Program of the State Grid Corporation of China under Grant GYB17201400178.
文摘When evaluating the electromagnetic environment of high voltage direct current(HVDC)powers lines,a fundamental factor to consider is the ionized field at ground level.China’s rapid industrialization and urbanization has led to haze pollution episodes.Ions generated by the corona discharge on the surface of HVDC power lines can adhere to haze particles,giving rise to variations in space charge density,which then impact the ionized field.In this paper,the charging and motion characteristics of the dielectric particle are investigated.The saturation charge amount of the particle and its contribution to the charge density are calculated in the spherical coordinates using the governing equations of the electric field.The terminal setting velocity is calculated based on the Stokes flow of particles in the gravitational and electrical fields.The mobility of the charged particle is also analyzed.This paper will serve as a valuable reference for the modeling and calculation of the ionized field of HVDC transmission lines,with the presence of dielectric particles.
