Helium-containing Ti Glms are prepared using magnetron sputtering in the helium-argon atmosphere. Isochronal annealing at different temperatures for an hour is employed to reveal the behaviour of helium bubble growth....Helium-containing Ti Glms are prepared using magnetron sputtering in the helium-argon atmosphere. Isochronal annealing at different temperatures for an hour is employed to reveal the behaviour of helium bubble growth. Ion beam analysis is used to measure the retained helium content. Helium can release largely when annealing above 970K. A thermal helium desorption spectroscopy system is constructed for assessment of the evolution of helium bubbles in the annealed samples by linear heating （OAK/s） from room temperature to 1500K. Also, Doppler broadening measurements of positron annihilation radiation spectrum are performed by using changeable energy positron beam. Bubble coarsening evolves gradually below 680K, migration and coalescence of small bubbles dominates in the range of 68-970 K, and the Ostwald ripening mechanism enlarges the bubbles with a massive release above 970K.展开更多
The computed tomography was applied to setting STIM(Scanning Transmission Ion Microscopy) projections recorded at the Fudan Ion Beam Laboratory.In this work,in order to visualize the three-dimensional mass density dis...The computed tomography was applied to setting STIM(Scanning Transmission Ion Microscopy) projections recorded at the Fudan Ion Beam Laboratory.In this work,in order to visualize the three-dimensional mass density distribution in several specimens,example for a test structure of hollow gold cyliner was presented together with a detailed description of the developed system,including data reconstruction code(Tomorebuild 2) and image display software(AMIRA).Future development will allow the particle induced X-ray emission tomography for elemental analysis of micrometer-sized samples.展开更多
We present a theoretical calculation finding that a spectrum from ion beam analysis will change at different stopping cross sections. This is more visible at a deeper place in the sample. Helium-contained Ti films ann...We present a theoretical calculation finding that a spectrum from ion beam analysis will change at different stopping cross sections. This is more visible at a deeper place in the sample. Helium-contained Ti films annealed at different temperatures are prepared to gain different stopping cross sections whereby the stopping cross section will change with the helium phase states and the pressure of helium bubbles. Then ion beam analysis is used to measure the concentration of helium. It is found that the concentration curve rises greatly after the sample is annealed at 673K which reflects the increasing size of the helium bubble. The results axe consistent with that of positron annihilation radiation spectra which are performed by using a changeable energy positron beam.展开更多
Based on a lognormal particle size distribution, this paper makes a model analysis on the polydispersity effects on the magnetization behaviour of diluted ferrofluids. Using a modified Langevin relationship for the lo...Based on a lognormal particle size distribution, this paper makes a model analysis on the polydispersity effects on the magnetization behaviour of diluted ferrofluids. Using a modified Langevin relationship for the lognormal dispersion, it first performs reduced calculations without material parameters. From the results, it is extrapolated that for the ferrofluid of lognormal polydispersion, in comparison with the corresponding monodispersion, the saturation magnetization is enhanced higher by the particle size distribution. It also indicates that in an equivalent magnetic field, the lognormally polydispersed ferrofluid is magnetically saturated faster than the corresponding monodispersion. Along the theoretical extrapolations, the polydispersity effects are evaluated for a typical ferrofluid of magnetite, with a dispersity of σ = 0.20. The results indicate that the lognormal polydispersity leads to a slight increase of the saturation magnetization, but a noticeable increase of the speed to reach the saturation value in an equivalent magnetic field.展开更多
The effect of charge current density on the growth of CN_(χ)films by electrolysis of a methanol-urea solution is investigated experimentally.It is seen that the C-C_(3)N_(4) phase grains in the films are about 200-30...The effect of charge current density on the growth of CN_(χ)films by electrolysis of a methanol-urea solution is investigated experimentally.It is seen that the C-C_(3)N_(4) phase grains in the films are about 200-300 nm for a density of 55 mA/cm^(2)and dendrite growth takes place with grains as large as 7μm formed when density is about 70 m A/cm^(2).展开更多
We carry out the first time-resolved measurement of Rb atoms desorbing from octadecyltrichlorosilane coated sur- faces by polarizing the atoms near the surface using an evanescent wave pump pulse and watching the subs...We carry out the first time-resolved measurement of Rb atoms desorbing from octadecyltrichlorosilane coated sur- faces by polarizing the atoms near the surface using an evanescent wave pump pulse and watching the subsequent intensity change of another evanescent wave probe beam, and find the mean adsorption （dwell） time to be about 400ns at a cell body temperature of 112℃. The adsorption energy is found to be 0.19eV from the surface tem- perature dependence of the adsorption time. This method can be extended to study the adsorption/desorption process of other alkali atoms on other surfaces of transparent substrates with an ultimate time resolution limited by the flight time of atoms in the evanescent wave which is of the order of nanoseconds.展开更多
Production of positron-electron (e^(+) e^(-) ) pairs in an intense laser pulse is investigated by solving the Dirac equation with analytical and numerical methods.We observe that the probability of the pair production...Production of positron-electron (e^(+) e^(-) ) pairs in an intense laser pulse is investigated by solving the Dirac equation with analytical and numerical methods.We observe that the probability of the pair production will firstly decrease slowly as the pulse length T becomes shortened.Then it will increase until T is reduced to the Compton time Tc =(h)/(mec) ≈ 1.29 × 10^(-21)s and finally decrease exponentially to zero.Hence,for a prominent pair production,we not only require that the electric field strength should be higher than the Schwinger critical value Ecr =m^(2)c^(3)/(e(h)) ≈ 1.32 × 10^(16) V/cm,but also that the pulse duration T should be larger than Tc.The latter is shown to be related to momentum requirement for the transition.For fields with different pulse lengths,the phase and chirp influences upon the pair production are also explored.展开更多
The equation of state for nuclear matter is presented within the Brueckner Hartree-Fock （BHF） scheme, by using the realistic Argonne VI8 or Bonn B two-nucleon potentials plus their corresponding microscopic three-nu...The equation of state for nuclear matter is presented within the Brueckner Hartree-Fock （BHF） scheme, by using the realistic Argonne VI8 or Bonn B two-nucleon potentials plus their corresponding microscopic three-nucleon forces. It is then applied to calculate the properties of finite nuclei within a simple liquid-drop model, and we compare the calculated volume, surface, and Coulomb parameters with the empirical ones from the liquid drop model. Nuclear density distributions and charge radii in good agreement with the experimental data are obtained~ and we predict the neutron skin thickness of various nuclei.展开更多
In this paper,we report a novel measurement system based on the development of Fudan Scanning Proton Microscopy(SPM) facility.By using Si-PIN diode(Hamamatsu S1223-01) detector,scanning transmission ion microscopy(STI...In this paper,we report a novel measurement system based on the development of Fudan Scanning Proton Microscopy(SPM) facility.By using Si-PIN diode(Hamamatsu S1223-01) detector,scanning transmission ion microscopy(STIM) measurement system has been set up.It can provide density and structural images with high probing efficiency and non-destruction by utilizing the energy loss of high energy(MeV) and focused ions penetrating through a thin sample.STIM measurement is able to map the density distribution of organic elements which mostly compose biology materials,such information can not be detected by using conventional Be-windowed Si(Li) X-ray detector in Particle Induced X-ray Emission(PIXE) technique.The spatial resolution capability of STIM is higher than PIXE technique at same accelerator status.As a result of STIM measurement,Paramecium attached on the top of Kapton tube was measured by STIM.展开更多
A simple model based on the statistics of single atoms is developed to predict the diffusion rate of thermal atoms in （or on） bulk materials without empirical parameters. Compared with vast classical molecular-dynam...A simple model based on the statistics of single atoms is developed to predict the diffusion rate of thermal atoms in （or on） bulk materials without empirical parameters. Compared with vast classical molecular-dynamics simulations for predicting the self-diffusion rate of Pt, Cu, and Ar adatoms on crystal surfaces, the model is proved to be much more accurate than the Arrhenius law and the transition state theory. Applying this model, the theoretical predictions agree well with the experimental values in the presented paper about the self-diffusion of Pt （Cu） adatoms on the surfaces.展开更多
External micro-PIXE measurements were done to investigate the accumulation of Nd^(3+)on green algae species euglena gracilis.According to the Nd distribution patterns in the gracilis cells,the biosorption of Nd^(3+)to...External micro-PIXE measurements were done to investigate the accumulation of Nd^(3+)on green algae species euglena gracilis.According to the Nd distribution patterns in the gracilis cells,the biosorption of Nd^(3+)to the cell's compartments can be observed.Comparing elemental mappings of the cell treated with different doses of the 1 mg/mL Nd^(3+)solution,the Nd uptake of euglena gracilis cells do no relate with the doses.From distributions of Ca and Mg,it is found that the Ca is complementary to Nd partly,and the Nd and Mg distributions are alike to each other,showing that Nd may be mainly in the chlorophyll molecules.The biochemistry related is discussed.展开更多
In nuclear structural materials, the nuclear irradiations induce the precipitations of soluble elements or produce the insoluble elements such as He atoms that may form clusters, heavily shortening the service life-ti...In nuclear structural materials, the nuclear irradiations induce the precipitations of soluble elements or produce the insoluble elements such as He atoms that may form clusters, heavily shortening the service life-times of the materials. In the present work, a diffusion model is developed to predict where and how fast the solute atoms （either soluble or insoluble） aggregate, and this model is applied to the study of the formation and growth of He bubbles in metal tritides （PdT0.6, ErT2, NbT0.0225, VT0.5, TaT0.097, TiT1.5, ZrT1.6） within one thousand days. The results are in good agreement with the available experimental observations and suggest that searching for metals with a barrier of more than 1.1 eV for a single He atom diffusion and making more defects in metal tritides can significantly reduce the growth of He bubbles and extend the service time of the metals.展开更多
Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effectiv...Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effective collision strengths） among the lowest 41 levels from the n = 3 configurations of Cu XV. The results show that the latter approach can obtain resonance contributions reasonably well for most excitations of Cu XV, though a comparison between the two approaches shows that the close-coupling effects are truly significant for rather weak excitations, especially for two-electron excitations from the 3s3p4 to 3s23p23d configuration. Resonance contributions are significant （more than two orders of magnitude） for many excitations and dramatically influence the line intensity ratios associated with density diagnostics.展开更多
The backward secondary electron emission yields of MeV ions(H^(+),He^(+),He^(++),Cl,Si,and Cu)impinging on thick carbon and gold targets are studied.The measured results for H+(1MeV≤E≤5MeV)on carbon are proportional...The backward secondary electron emission yields of MeV ions(H^(+),He^(+),He^(++),Cl,Si,and Cu)impinging on thick carbon and gold targets are studied.The measured results for H+(1MeV≤E≤5MeV)on carbon are proportional to the electronic stopping power.Our experimental data and fitting formula of yields for H+(1 MeV≤E≤4.5MeV)impacting Au are compared with the theoretical expectation.The influence of the collective field and the charge state of ions on the secondary electron emission yield is discussed.展开更多
From numerical simulations,we study the generation of quasi-monoenergetic MeV proton beams from a laserilluminated funnel-like target.We show that,when passing through such a target,the laser beam can be focused and c...From numerical simulations,we study the generation of quasi-monoenergetic MeV proton beams from a laserilluminated funnel-like target.We show that,when passing through such a target,the laser beam can be focused and constricted within a cylindrical bore at the funnel apex from which proton beams are produced.Accompanied by a much-enhanced laser intensity,the proton beams experience more acceleration time than with normal funnel targets.Constriction from the cylinder bore,combined with an enhancement of a separated charge field from Al electrons,protons can attain higher energies up to several tens of MeV.At the same time,strong suppression of the transverse divergence of the laser and proton beams yields a localized,collimated,mono-energetic proton beam.展开更多
The single-electron detachment cross sections of Cu^(-) in collision with He have been measured in the range of 10-30keV by a growth rate method. The typical value of the cross section is 7.63×10-16 cm^(2) at an ...The single-electron detachment cross sections of Cu^(-) in collision with He have been measured in the range of 10-30keV by a growth rate method. The typical value of the cross section is 7.63×10-16 cm^(2) at an energy of 20 keV. The experimental uncertainty of the results is about ±8%.展开更多
A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-co...A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-configuration Dirac-Hartree- Fock method in the active space approximation. It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons, and the correlation with the 2s electron is also noticeable. The core-core correlation seems to be small and can be ignored. The calculated 2D3/2,5/2 splitting energies agree with the recent electron-beam ion-trap measurements [Phys. Rev. A 83 032517 （2011）, Eur. Phys. J. D 66 286 （2012）] to within the experimental uncertainties.展开更多
We prepare p-type ZnO:N films by annealing Zn_(3)N_(2) films in oxygen over a range of temperatures.The prepared films are characterized by various techniques,such as Rutherford backscattering spectroscopy,x-ray diffr...We prepare p-type ZnO:N films by annealing Zn_(3)N_(2) films in oxygen over a range of temperatures.The prepared films are characterized by various techniques,such as Rutherford backscattering spectroscopy,x-ray diffraction,x-ray photoemission spectroscopy,the Hall effect and photoluminescence spectra.The results show that the Zn_(3)N_(2) films start to transform to ZnO at 300℃ and the N content decreases with an increase in annealing temperature.N has two local chemical states:zinc oxynitride(ZnO_(1-x)N_(x))and substitutional NO in O-rich local environments(α-NO).The conduction type changes from n-type to p-type upon oxidation at 400-600℃,indicating that N is an effective acceptor in the ZnO film.The photoluminescence spectra show the UV emission and defect-related emissions of ZnO:N films.The mechanism and efficiency of p-type doping are briefly discussed.展开更多
A new method prepared for helium and hydrogen co-containing Zr films is presented to simulate aging metal tritides, in which direct current magnetron sputtering with a He/H/Ar mixture is used. The retained amount and ...A new method prepared for helium and hydrogen co-containing Zr films is presented to simulate aging metal tritides, in which direct current magnetron sputtering with a He/H/Ar mixture is used. The retained amount and depth profiles of helium and hydrogen are determined by elastic recoil detection analysis. Thermal desorption spectrometry is applied to investigate He thermal release and the effect of hydrogen. It is found that the hightemperature peaks with a large mount of helium release obviously shifted toward lower temperature at high hydrogen concentration, especially at the hydride transformation region, and that the shapes of the release peaks also changed due to the additional hydrogen. However, at the low-temperature releasing region the peak intense decreases when phase transformation takes place. The mechanism of helium thermal release and the effect of hydrogen are also discussed.展开更多
This paper proposes highly charged ions pumped by intense laser to produce very high order harmonics. Numerical simulations and full quantum theory of Ne^9＋ ions driven by laser pulses at 1064 nm in the power range o...This paper proposes highly charged ions pumped by intense laser to produce very high order harmonics. Numerical simulations and full quantum theory of Ne^9＋ ions driven by laser pulses at 1064 nm in the power range of 109 W/cm^2 1015 W/cm^2 show that the emission spectrum corresponds to the electronic transitions from the excited states to the ground state, which is very different from the spectrum of general high-order harmonic generation. In such situation, harmonic order as high as 1000 can be obtained without producing lower order harmonics and the energy conversion efficiency is close to general high order harmonic generation of hydrogen atom in the same laser field.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10176008, 50131050 and 10475016.
文摘Helium-containing Ti Glms are prepared using magnetron sputtering in the helium-argon atmosphere. Isochronal annealing at different temperatures for an hour is employed to reveal the behaviour of helium bubble growth. Ion beam analysis is used to measure the retained helium content. Helium can release largely when annealing above 970K. A thermal helium desorption spectroscopy system is constructed for assessment of the evolution of helium bubbles in the annealed samples by linear heating （OAK/s） from room temperature to 1500K. Also, Doppler broadening measurements of positron annihilation radiation spectrum are performed by using changeable energy positron beam. Bubble coarsening evolves gradually below 680K, migration and coalescence of small bubbles dominates in the range of 68-970 K, and the Ostwald ripening mechanism enlarges the bubbles with a massive release above 970K.
基金Supported by Chinese National Science Foundation under the Grant(No.10975034)
文摘The computed tomography was applied to setting STIM(Scanning Transmission Ion Microscopy) projections recorded at the Fudan Ion Beam Laboratory.In this work,in order to visualize the three-dimensional mass density distribution in several specimens,example for a test structure of hollow gold cyliner was presented together with a detailed description of the developed system,including data reconstruction code(Tomorebuild 2) and image display software(AMIRA).Future development will allow the particle induced X-ray emission tomography for elemental analysis of micrometer-sized samples.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10675034 and 10475016, and the Shanghai Leading Academic Discipline Project （B107）.
文摘We present a theoretical calculation finding that a spectrum from ion beam analysis will change at different stopping cross sections. This is more visible at a deeper place in the sample. Helium-contained Ti films annealed at different temperatures are prepared to gain different stopping cross sections whereby the stopping cross section will change with the helium phase states and the pressure of helium bubbles. Then ion beam analysis is used to measure the concentration of helium. It is found that the concentration curve rises greatly after the sample is annealed at 673K which reflects the increasing size of the helium bubble. The results axe consistent with that of positron annihilation radiation spectra which are performed by using a changeable energy positron beam.
基金Project supported by the Shanghai Leading Academic Discipline Project of China (Grant No. B107)
文摘Based on a lognormal particle size distribution, this paper makes a model analysis on the polydispersity effects on the magnetization behaviour of diluted ferrofluids. Using a modified Langevin relationship for the lognormal dispersion, it first performs reduced calculations without material parameters. From the results, it is extrapolated that for the ferrofluid of lognormal polydispersion, in comparison with the corresponding monodispersion, the saturation magnetization is enhanced higher by the particle size distribution. It also indicates that in an equivalent magnetic field, the lognormally polydispersed ferrofluid is magnetically saturated faster than the corresponding monodispersion. Along the theoretical extrapolations, the polydispersity effects are evaluated for a typical ferrofluid of magnetite, with a dispersity of σ = 0.20. The results indicate that the lognormal polydispersity leads to a slight increase of the saturation magnetization, but a noticeable increase of the speed to reach the saturation value in an equivalent magnetic field.
基金Supported by the National Natural Science Foundation of China under Grant No 10574030the Shanghai Leading Academic Discipline Project under Grant No B107.
文摘The effect of charge current density on the growth of CN_(χ)films by electrolysis of a methanol-urea solution is investigated experimentally.It is seen that the C-C_(3)N_(4) phase grains in the films are about 200-300 nm for a density of 55 mA/cm^(2)and dendrite growth takes place with grains as large as 7μm formed when density is about 70 m A/cm^(2).
基金Supported by the National Natural Science Foundation of China under Grant No 11074050
文摘We carry out the first time-resolved measurement of Rb atoms desorbing from octadecyltrichlorosilane coated sur- faces by polarizing the atoms near the surface using an evanescent wave pump pulse and watching the subsequent intensity change of another evanescent wave probe beam, and find the mean adsorption （dwell） time to be about 400ns at a cell body temperature of 112℃. The adsorption energy is found to be 0.19eV from the surface tem- perature dependence of the adsorption time. This method can be extended to study the adsorption/desorption process of other alkali atoms on other surfaces of transparent substrates with an ultimate time resolution limited by the flight time of atoms in the evanescent wave which is of the order of nanoseconds.
基金Supported by the National Natural Science Foundation of China under Grant No 10974056 and 10975036Shanghai Pujiang Talent Project under Grant No 07pj14036.
文摘Production of positron-electron (e^(+) e^(-) ) pairs in an intense laser pulse is investigated by solving the Dirac equation with analytical and numerical methods.We observe that the probability of the pair production will firstly decrease slowly as the pulse length T becomes shortened.Then it will increase until T is reduced to the Compton time Tc =(h)/(mec) ≈ 1.29 × 10^(-21)s and finally decrease exponentially to zero.Hence,for a prominent pair production,we not only require that the electric field strength should be higher than the Schwinger critical value Ecr =m^(2)c^(3)/(e(h)) ≈ 1.32 × 10^(16) V/cm,but also that the pulse duration T should be larger than Tc.The latter is shown to be related to momentum requirement for the transition.For fields with different pulse lengths,the phase and chirp influences upon the pair production are also explored.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11075037 and 11475045the Scientific Research Foundation for the Returned Overseas Chinese Scholars of the Ministry of Education of China+2 种基金the Fundamental Research Funds for the Central Universities of Chinathe Shanghai Leading Academic Discipline Project under Grant No B107the 'NewCompStar',COST Action MP1304
文摘The equation of state for nuclear matter is presented within the Brueckner Hartree-Fock （BHF） scheme, by using the realistic Argonne VI8 or Bonn B two-nucleon potentials plus their corresponding microscopic three-nucleon forces. It is then applied to calculate the properties of finite nuclei within a simple liquid-drop model, and we compare the calculated volume, surface, and Coulomb parameters with the empirical ones from the liquid drop model. Nuclear density distributions and charge radii in good agreement with the experimental data are obtained~ and we predict the neutron skin thickness of various nuclei.
基金Supported by Shanghai Synchrotron Radiation Facility project
文摘In this paper,we report a novel measurement system based on the development of Fudan Scanning Proton Microscopy(SPM) facility.By using Si-PIN diode(Hamamatsu S1223-01) detector,scanning transmission ion microscopy(STIM) measurement system has been set up.It can provide density and structural images with high probing efficiency and non-destruction by utilizing the energy loss of high energy(MeV) and focused ions penetrating through a thin sample.STIM measurement is able to map the density distribution of organic elements which mostly compose biology materials,such information can not be detected by using conventional Be-windowed Si(Li) X-ray detector in Particle Induced X-ray Emission(PIXE) technique.The spatial resolution capability of STIM is higher than PIXE technique at same accelerator status.As a result of STIM measurement,Paramecium attached on the top of Kapton tube was measured by STIM.
基金Project supported by the National Natural Science Foundation of China(Grant No.51071048)
文摘A simple model based on the statistics of single atoms is developed to predict the diffusion rate of thermal atoms in （or on） bulk materials without empirical parameters. Compared with vast classical molecular-dynamics simulations for predicting the self-diffusion rate of Pt, Cu, and Ar adatoms on crystal surfaces, the model is proved to be much more accurate than the Arrhenius law and the transition state theory. Applying this model, the theoretical predictions agree well with the experimental values in the presented paper about the self-diffusion of Pt （Cu） adatoms on the surfaces.
基金Supported by the National Natural Science Foundation of China(Nos.10675033 and 10975034)
文摘External micro-PIXE measurements were done to investigate the accumulation of Nd^(3+)on green algae species euglena gracilis.According to the Nd distribution patterns in the gracilis cells,the biosorption of Nd^(3+)to the cell's compartments can be observed.Comparing elemental mappings of the cell treated with different doses of the 1 mg/mL Nd^(3+)solution,the Nd uptake of euglena gracilis cells do no relate with the doses.From distributions of Ca and Mg,it is found that the Ca is complementary to Nd partly,and the Nd and Mg distributions are alike to each other,showing that Nd may be mainly in the chlorophyll molecules.The biochemistry related is discussed.
基金Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20130071110018)the National Natural Science Foundation of China(Grant No.11274073)
文摘In nuclear structural materials, the nuclear irradiations induce the precipitations of soluble elements or produce the insoluble elements such as He atoms that may form clusters, heavily shortening the service life-times of the materials. In the present work, a diffusion model is developed to predict where and how fast the solute atoms （either soluble or insoluble） aggregate, and this model is applied to the study of the formation and growth of He bubbles in metal tritides （PdT0.6, ErT2, NbT0.0225, VT0.5, TaT0.097, TiT1.5, ZrT1.6） within one thousand days. The results are in good agreement with the available experimental observations and suggest that searching for metals with a barrier of more than 1.1 eV for a single He atom diffusion and making more defects in metal tritides can significantly reduce the growth of He bubbles and extend the service time of the metals.
基金supported by the National Natural Science Foundation of China(Grant Nos.11076009 and 11374062)the Chinese Association of Atomic and Molecular Data,the Chinese National Fusion Project for ITER(Grant No.2015GB117000)the Leading Academic Discipline Project of Shanghai,China(Grant No.B107)
文摘Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effective collision strengths） among the lowest 41 levels from the n = 3 configurations of Cu XV. The results show that the latter approach can obtain resonance contributions reasonably well for most excitations of Cu XV, though a comparison between the two approaches shows that the close-coupling effects are truly significant for rather weak excitations, especially for two-electron excitations from the 3s3p4 to 3s23p23d configuration. Resonance contributions are significant （more than two orders of magnitude） for many excitations and dramatically influence the line intensity ratios associated with density diagnostics.
文摘The backward secondary electron emission yields of MeV ions(H^(+),He^(+),He^(++),Cl,Si,and Cu)impinging on thick carbon and gold targets are studied.The measured results for H+(1MeV≤E≤5MeV)on carbon are proportional to the electronic stopping power.Our experimental data and fitting formula of yields for H+(1 MeV≤E≤4.5MeV)impacting Au are compared with the theoretical expectation.The influence of the collective field and the charge state of ions on the secondary electron emission yield is discussed.
基金Supported by the National Natural Science Foundation of China under Grant No 11175048the Shanghai Nature Science Foundation(No 11ZR1402700)+2 种基金the Shanghai Scientific Research Innovation Key Project(No 12ZZ011)The Shanghai Leading Academic Discipline Project(B107)the JSPS-CAS CUP Program and the CORE of Utsunomiya University.
文摘From numerical simulations,we study the generation of quasi-monoenergetic MeV proton beams from a laserilluminated funnel-like target.We show that,when passing through such a target,the laser beam can be focused and constricted within a cylindrical bore at the funnel apex from which proton beams are produced.Accompanied by a much-enhanced laser intensity,the proton beams experience more acceleration time than with normal funnel targets.Constriction from the cylinder bore,combined with an enhancement of a separated charge field from Al electrons,protons can attain higher energies up to several tens of MeV.At the same time,strong suppression of the transverse divergence of the laser and proton beams yields a localized,collimated,mono-energetic proton beam.
基金Supported by the National Natural Science Foundation of China under Grant No.19874015。
文摘The single-electron detachment cross sections of Cu^(-) in collision with He have been measured in the range of 10-30keV by a growth rate method. The typical value of the cross section is 7.63×10-16 cm^(2) at an energy of 20 keV. The experimental uncertainty of the results is about ±8%.
基金supported by the National Natural Science Foundation of China(Grant Nos.11076009 and 11374062)the Chinese Association of Atomic and Molecular Data+1 种基金the Chinese National Fusion Project for ITER(Grant No.2015GB117000)the Leading Academic Discipline Project of Shanghai City,China(Grant No.B107)
文摘A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-configuration Dirac-Hartree- Fock method in the active space approximation. It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons, and the correlation with the 2s electron is also noticeable. The core-core correlation seems to be small and can be ignored. The calculated 2D3/2,5/2 splitting energies agree with the recent electron-beam ion-trap measurements [Phys. Rev. A 83 032517 （2011）, Eur. Phys. J. D 66 286 （2012）] to within the experimental uncertainties.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775033 and 11075038.
文摘We prepare p-type ZnO:N films by annealing Zn_(3)N_(2) films in oxygen over a range of temperatures.The prepared films are characterized by various techniques,such as Rutherford backscattering spectroscopy,x-ray diffraction,x-ray photoemission spectroscopy,the Hall effect and photoluminescence spectra.The results show that the Zn_(3)N_(2) films start to transform to ZnO at 300℃ and the N content decreases with an increase in annealing temperature.N has two local chemical states:zinc oxynitride(ZnO_(1-x)N_(x))and substitutional NO in O-rich local environments(α-NO).The conduction type changes from n-type to p-type upon oxidation at 400-600℃,indicating that N is an effective acceptor in the ZnO film.The photoluminescence spectra show the UV emission and defect-related emissions of ZnO:N films.The mechanism and efficiency of p-type doping are briefly discussed.
基金Supported by the National Natural Science Foundation of China under Grant No 10475016.
文摘A new method prepared for helium and hydrogen co-containing Zr films is presented to simulate aging metal tritides, in which direct current magnetron sputtering with a He/H/Ar mixture is used. The retained amount and depth profiles of helium and hydrogen are determined by elastic recoil detection analysis. Thermal desorption spectrometry is applied to investigate He thermal release and the effect of hydrogen. It is found that the hightemperature peaks with a large mount of helium release obviously shifted toward lower temperature at high hydrogen concentration, especially at the hydride transformation region, and that the shapes of the release peaks also changed due to the additional hydrogen. However, at the low-temperature releasing region the peak intense decreases when phase transformation takes place. The mechanism of helium thermal release and the effect of hydrogen are also discussed.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10574030)
文摘This paper proposes highly charged ions pumped by intense laser to produce very high order harmonics. Numerical simulations and full quantum theory of Ne^9＋ ions driven by laser pulses at 1064 nm in the power range of 109 W/cm^2 1015 W/cm^2 show that the emission spectrum corresponds to the electronic transitions from the excited states to the ground state, which is very different from the spectrum of general high-order harmonic generation. In such situation, harmonic order as high as 1000 can be obtained without producing lower order harmonics and the energy conversion efficiency is close to general high order harmonic generation of hydrogen atom in the same laser field.
