In recent years, the collective motion properties of global rotation of the symmetric colliding system in relativistic energies have been investigated. In addition, the initial geometrical shape effects on the collect...In recent years, the collective motion properties of global rotation of the symmetric colliding system in relativistic energies have been investigated. In addition, the initial geometrical shape effects on the collective flows have been explored using a hydrodynamical model, a transport model, etc. In this work, we study the asymmetric ^(12)C+^(197)Au collision at 200 GeV/c and the effect of the exotic nuclear structure on the global rotation using a multi-phase transport model. The global angular momentum and averaged angular speed were calculated and discussed for the collision system at different evolution stages.展开更多
AIM： To determine whether the number of non-rejoining G2-chromatid breaks can predict the radiosensitivity of human cell lines. METHODS： Cell lines of human ovary carcinoma cells （HO8910）, human hepatoma cells （H...AIM： To determine whether the number of non-rejoining G2-chromatid breaks can predict the radiosensitivity of human cell lines. METHODS： Cell lines of human ovary carcinoma cells （HO8910）, human hepatoma cells （HepG2） and liver cells （L02） were irradiated with a range of doses and assessed both of cell survival and non-rejoining G2-chromatid breaks at 24 h after irradiation. Cell survival was documented by a colony assay. Non-rejoining G2-chromatid breaks were measured by counting the number of non-rejoining G2 chromatid breaks at 24 h after irradiation, detected by the prematurely chromosome condensed （PCC） technique. RESULTS： A linear-quadratic survival curve was observed in three cell lines, and HepG2 was the most sensitive to γ-radiaUon. A dose-dependent linear increase was observed in radiation-induced non-rejoining G2- PCC breaks measured at 24 h after irradiation in all cell lines, and HepG2 was the most susceptible to induction of non-rejoining G2-PCC breaks. A close correlation was found between the clonogenic radiosensitivity and the radiation-induced non-rejoining G2-PCC breaks （r=0.923）. Furthermore, survival-aberration correlations for two or more than two doses lever were also significant. CONCLUSION： The number of non-rejoining G2 PCC breaks holds considerable promise for predicting the radiosensitMty of normal and tumor cells when two or more than two doses lever is tested.展开更多
Molecular dynamics simulations are used to investigate the stabilities of C15 Laves phase structures subjected to temperature and point defects. The simulations based on different empirical potentials show that the bu...Molecular dynamics simulations are used to investigate the stabilities of C15 Laves phase structures subjected to temperature and point defects. The simulations based on different empirical potentials show that the bulk perfect C15 Laves phase appears to be stable under a critical temperature in a range from 350 K to 450 K, beyond which it becomes disordered and experiences an abrupt decrement of elastic modulus. In the presence of both vacancy and self-interstitial, the bulk C15 Laves phase becomes unstable at room temperature and prefers to transform into an imperfect body centered cubic（BCC）structure containing free vacancies or vacancy clusters. When a C15 cluster is embedded in BCC iron, the annihilation of interstitials occurs due to the presence of the vacancy, while it exhibits a phase transformation into a（1/2） 111 dislocation loop due to the presence of the self-interstitial.展开更多
Heavy-ion flux is an important experimental parameter in the ground based single event tests. The flux impact on a single event effect in different memory devices is analyzed by using GEANT4 and TCAD simulation method...Heavy-ion flux is an important experimental parameter in the ground based single event tests. The flux impact on a single event effect in different memory devices is analyzed by using GEANT4 and TCAD simulation methods. The transient radial track profile depends not only on the linear energy transfer （LET） of the incident ion, but also on the mass and energy of the ion. For the ions with the energies at the Bragg peaks, the radial charge distribution is wider when the ion LET is larger. The results extracted from the GEANT4 and TCAD simulations, together with detailed analysis of the device structure, are presented to demonstrate phenomena observed in the flux related experiment. The analysis shows that the flux effect conclusions drawn from the experiment are intrinsically connected and all indicate the mechanism that the flux effect stems from multiple ion-induced pulses functioning together and relies exquisitely on the specific response of the device.展开更多
It has remained an open problem to accurately compute the partition function of macroscopic systems since the establishment of statistical physics. A rapid method approaching this problem was presented and was strictl...It has remained an open problem to accurately compute the partition function of macroscopic systems since the establishment of statistical physics. A rapid method approaching this problem was presented and was strictly tested by molecular dynamic （MD） simulations on Ar atoms in both dense gaseous and liquid states. The outcomes from the method on the internal energy and the work of isothermal expansion （and therefore the free energy） are in good agreement with the MD simulations, suggesting the method would be immediately applied in vast areas.展开更多
We have set up an experimental system consisting of an im gun and a Rutherford backscattering spectro-metry(RBS)analysis chamber.Using this system,in situ 2MeV*He+RBS analysis of films is carried out by combination wi...We have set up an experimental system consisting of an im gun and a Rutherford backscattering spectro-metry(RBS)analysis chamber.Using this system,in situ 2MeV*He+RBS analysis of films is carried out by combination with sputter etching cf low energy Ar+ions.As an example of the sputtering/RBS method,the analysis of three samples,i.e.,Si/(GexSi_(1-x)/Si)/Si(100),WSi_(x)/SiO_(2)/Si and CoSi_(x)/Si,is presented in this paper.After an appropriate fraction of the thick layer is removed by sputtering,the back edge of the Ge peak is separated from Si RBS spectmm on the interface and the O peak of the buried S1O2 layer can be identified.The change cf the doped Ti and W concentrations related to Co on the top surface is observed.The advantages of this analytical method and its possible applications in film are discussed.展开更多
Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) a...Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) and Σ^(-) in the timelike region are investigated using the vector-meson dominance model,where the contributions of theρ,ω,and φ mesons are taken into account.The model parameters are determined from the BESⅢexperimental data of the timelike effective form factors|G_(eff)|of the Σ^(+) and Σ^(-) baryons for center-of-mass energies from 2.3864 to 3.02 GeV.It is found that we can provide quantitative descriptions of the available data using as few as one adjustable model parameter.We then progress to an analysis of the electromagnetic form factors in the spacelike region and evaluate the spacelike form factors of the hyperons Σ^(+) and Σ^(-).The electromagnetic form factors obtained for the Σ^(+) and Σ^(-) baryons are comparable with those of other model calculations.展开更多
Dielectronic recombination is an important process in high temperature plasmas. In the present work, the KLn （n=L, M, N and O） DR resonance strengths of He-like to O-like xenon ions are measured at the Shanghai elec...Dielectronic recombination is an important process in high temperature plasmas. In the present work, the KLn （n=L, M, N and O） DR resonance strengths of He-like to O-like xenon ions are measured at the Shanghai electron beam ion trap using a fast electron beam energy scanning method. The experiment uncertainty reaches about 6% with significant improvement of statistics. A relativistic configuration interaction calculation is also made. Theoretical results agree with the experiment results within 15% in most cases.展开更多
The head on collision between two opposite propagating solitary waves is studied in the present paper both numerically and analytically.The interesting result is that no phase shift is observed which is different from...The head on collision between two opposite propagating solitary waves is studied in the present paper both numerically and analytically.The interesting result is that no phase shift is observed which is different from that found in other branches of physics.It is found that the maximum amplitude in the process of the head on collision is close to the linear sum of two colliding solitary waves.展开更多
The three lowest-lying r states,ie,r(1S),T(2S),and r(35),composed of b pairs and below the BB threshold,provide a good platform for the researches of hadronic physics and physics beyond the Standard Model.They can be ...The three lowest-lying r states,ie,r(1S),T(2S),and r(35),composed of b pairs and below the BB threshold,provide a good platform for the researches of hadronic physics and physics beyond the Standard Model.They can be produced directly in ete--colliding experiments,such as CLEO,Babar,and Belle,with low continuum backgrounds.In these experiments,many measurements of the exclusive r(1S)and r(2S)decays into light hadrons,which shed light on the"80%rule"for the Okubo-Zweig-lizuka suppressed decays in the bottomonium sector,were carried out.Meanwhile,many studies of the charmonium and bottomonium productions in r(1S,2S,3S)decays were performed,to distinguish different Quantum Chromodynamics(QCD)models.Besides,exotic states and new physics were also extensively explored in r(1S,2S,3S)decays at CLEO,BaBar,and Bell.The r(1S,2S,3S)states can also be produced in p collisions and in ollisions involving heavy ions.The precision measurements of their cross sections and polarizations at the large hadron collider(LHC),especially in the CMS,ATLAS,and LHCb experiments,help to understand r production mechanisms in Pp collisions.The observation of the sequential r suppession in heavy ion collisions at CMS,LHCb,and ALICE is of great importance for verifying the quark-gluon plasma predicted by QCD.In this article,we review the experimental results on T(1S,2S,3S)at e+e-colliders and the LHC,and summarize their prospects at Belle II and the LHC.展开更多
We explore the general characteristics of a matter-wave Sagnac interferometer in a two-parameter estimation scheme. We find that the measurement precisions of both parameters cannot reach the Heisenberg limit(HL) simu...We explore the general characteristics of a matter-wave Sagnac interferometer in a two-parameter estimation scheme. We find that the measurement precisions of both parameters cannot reach the Heisenberg limit(HL) simultaneously when the input state is maximally entangled. Only one of the parameters' uncertainties can approach the HL while the other is scaled by the standard quantum limit.We provide the conditions with which the measurement precision of the specific parameter can reach the HL. We also discuss and figure out the concrete expressions of the constraint conditions for saturating the quantum Cramér–Rao bound. To satisfy these constraint conditions, the evolution time has to be a series of discrete values. Additionally, we calculate the variances of the parameters through some examples under these constraint conditions. The results provided in our work show some intrinsic features of the matter-wave Sagnac interferometer for the two-parameter estimation, which can be valuable in actual experiments.展开更多
This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric （T1/2〉 100 ns） states. All nuclides for whic...This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric （T1/2〉 100 ns） states. All nuclides for which any experimental information is known were considered. NUSASE2016 covers all data published by October 2016 in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2016, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted and critically assessed for their validity and completeness. Furthermore, a large amount of new data and some older experimental results that were missing from ENSDF were compiled, evaluated and included in NUBASE2016. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2016, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclides （TNN） were examined. This approach allowed to estimate values for a range of properties that are labeled in NUBASE2016 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.展开更多
This paper is the second part of the new evaluation of atomic masses, AME2012. From the results of a leastsquares calculation, described in Part I, for all accepted experimental data, we derive here tables and graphs ...This paper is the second part of the new evaluation of atomic masses, AME2012. From the results of a leastsquares calculation, described in Part I, for all accepted experimental data, we derive here tables and graphs to replace those of AME2003. The first table lists atomic masses. It is followed by a table of the influences of data on primary nuclides, a table of separation energies and reaction energies, and finally, a series of graphs of separation and decay energies. The last section in this paper lists all references to the input data used in Part I of this AME2012 and also to the data included in the NUBASE2012 evaluation （first paper in this issue）.展开更多
This paper presents the NUBASE2012 evaluation that contains the recommended values for nuclear and decay properties of nuclides in their ground and excited isomeric （T1/2≥ 100 ns） states. All nuclides for which som...This paper presents the NUBASE2012 evaluation that contains the recommended values for nuclear and decay properties of nuclides in their ground and excited isomeric （T1/2≥ 100 ns） states. All nuclides for which some experimental information is known are considered. NUBASE2012 covers all up to date experimental data published in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2012, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted, and critically assessed of their validity and completeness. Furthermore, a large amount of new and somewhat older experimental results that were missing in ENSDF were compiled, evaluated and included in NUI3ASE2012. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2012, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclei （TNN） were examined. This approach allowed to estimate, whenever possible, values for a range of properties, and are labeled in NUBASE2012 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies that were used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.展开更多
The multinucleon transfer reaction in the collisions of 40 Ca+^124 Sn at Ec.m.= 128.5 MeV is investigated using the improved quantum molecular dynamics model. The measured angular distributions and isotopic distributi...The multinucleon transfer reaction in the collisions of 40 Ca+^124 Sn at Ec.m.= 128.5 MeV is investigated using the improved quantum molecular dynamics model. The measured angular distributions and isotopic distributions of the products are reproduced reasonably well by the calculations. The multinucleon transfer reactions of 40 Ca+^112 Sn, 58 Ni+^112 Sn, 106 Cd+^112 Sn, and 48 Ca+^112 Sn are also studied. This demonstrates that the combinations of neutron-deficient projectile and target are advantageous for the production of exotic neutron-deficient nuclei near N,Z =50. The charged particles’ emission plays an important role at small impact parameters in the de-excitation processes of the system. The production cross sections of the exotic neutron-deficient nuclei in multinucleon transfer reactions are much larger than those measured in the fragmentation and fusion-evaporation reactions. Several new neutron-deficient nuclei can be produced in the 106 Cd+^112 Sn reaction. The corresponding production cross sections for the new neutron-deficient nuclei,101,112 Sb,103 Te,and 106,107) I,are 2.0 nb,4.1 nb,6.5 nb,0.4 μb and 1.0 μb,respectively.展开更多
The effects of increased intraspecific competition on size hierarchies （size inequality） and reproductive allocation were investigated in populations of the annual plant, spring wheat （Triticurn aestivurn）. A seri...The effects of increased intraspecific competition on size hierarchies （size inequality） and reproductive allocation were investigated in populations of the annual plant, spring wheat （Triticurn aestivurn）. A series of densities （100, 300, 1 000, 3 000 and 10 000 plants/m^2） along a gradient of competition intensity were designed in this experiment. The results showed that average shoot biomass decreased with increased density. Reproductive allocation was negatively correlated to Gini coefficient （R^2 = 0.927）, which suggested that reproductive allocation is inclined to decrease as size inequality increases. These results suggest that both vegetative and reproductive structures were significantly affected by intensive competition. However, results also indicated that there were different relationships between plant size and reproductive allocation pattern in different densities. In the lowest density population, lacking competition （100 plants/m^2）, individual reproductive allocation was size independent but, in high density populations （300, 1 000, 3 000 and 10 000 plants/m^2）, where competition occurred, individual reproductive allocation was size dependent： the small proportion of larger individuals were winners in competition and got higher reproductive allocation （lower marginal reproductive allocation; MRA）, and the larger proportion of smaller individuals were suppressed and got lower reproductive allocation （higher MRA）. In conclusion, our results support the prediction that elevated intraspecific competition would result in higher levels of size inequality and decreased reproductive allocation （with a negative relationship between them）. However, deeper analysis indicated that these frequency- and size-dependent reproductive strategies were not evolutionarily stable strategies.展开更多
TheΛseparation energy forΛhypernuclei,denoted BΛ,measured in 1967,1968,and 1973 are recalibrated using the current best estimates of the mass of particles and nuclei.The recalibrated BΛare systematically larger(ex...TheΛseparation energy forΛhypernuclei,denoted BΛ,measured in 1967,1968,and 1973 are recalibrated using the current best estimates of the mass of particles and nuclei.The recalibrated BΛare systematically larger(except in the case ofΛ~6He)than the originally published values by about 100 keV.The effect of this level of recalibration is very important for light hypemuclei,especially for the hypertriton.The early BΛvalues measured in1967,1968,and 1973 are widely used in theoretical research,and the new results provide better constraints for the conclusions of such studies.展开更多
Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Prev...Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.展开更多
Ⅰ. INTRODUCTIONMuch work has been done on the modification and phase analysis after N^+ implatation for various carbon content steel, low alloy steel and stainless steel containing low carbon. This article reports th...Ⅰ. INTRODUCTIONMuch work has been done on the modification and phase analysis after N^+ implatation for various carbon content steel, low alloy steel and stainless steel containing low carbon. This article reports the observed modification of 9Cr18 steel after N^+ implatation, and the investigation of the phase variation within the N^+ implantation layer by conversion electron Mssbauer spectroscopy (CEMS)method and X-ray diffraction. Some discussions are also given.展开更多
The de-excited spectra of FeI and CuI after the interaction of Fe+ and Cu+ ions with a carbon foil (8.5μg/cm2) have been investigated by using the Beam-foil(BF) technique at an incident energy of 110 keV.The measured...The de-excited spectra of FeI and CuI after the interaction of Fe+ and Cu+ ions with a carbon foil (8.5μg/cm2) have been investigated by using the Beam-foil(BF) technique at an incident energy of 110 keV.The measured lines in the spectra are mainly from de-excited atoms FeI and CuI.The lifetime of stronger lines,including seven lines of FeI and three lines of CuI of the spectra are also measured.Some progress has been made in preparing foils with high quality and in adjusting the intensity of ion beams During measurements,the lifetime of carbon foil targets is more than 30 minutes.展开更多
基金supported in part by National Key R&D Program of China(No.2016YFE0100900)the National Natural Science Foundation of China(Nos.11421505,11220101005,11775288,and U1232206)+2 种基金the Major State Basic Research Development Program in China(No.2014CB845400)the Key Research Program of Frontier Sciences of the CAS(No.QYZDJ-SSW-SLH002)the Key Research Program of the Chinese Academy of Sciences(No.XDPB09)
文摘In recent years, the collective motion properties of global rotation of the symmetric colliding system in relativistic energies have been investigated. In addition, the initial geometrical shape effects on the collective flows have been explored using a hydrodynamical model, a transport model, etc. In this work, we study the asymmetric ^(12)C+^(197)Au collision at 200 GeV/c and the effect of the exotic nuclear structure on the global rotation using a multi-phase transport model. The global angular momentum and averaged angular speed were calculated and discussed for the collision system at different evolution stages.
基金Supported by the Key Project of National Natural Science Foundation of China, No. 10335050the Key Project of Ministry of Science and Technology of China, No. 2003CCB00200
文摘AIM： To determine whether the number of non-rejoining G2-chromatid breaks can predict the radiosensitivity of human cell lines. METHODS： Cell lines of human ovary carcinoma cells （HO8910）, human hepatoma cells （HepG2） and liver cells （L02） were irradiated with a range of doses and assessed both of cell survival and non-rejoining G2-chromatid breaks at 24 h after irradiation. Cell survival was documented by a colony assay. Non-rejoining G2-chromatid breaks were measured by counting the number of non-rejoining G2 chromatid breaks at 24 h after irradiation, detected by the prematurely chromosome condensed （PCC） technique. RESULTS： A linear-quadratic survival curve was observed in three cell lines, and HepG2 was the most sensitive to γ-radiaUon. A dose-dependent linear increase was observed in radiation-induced non-rejoining G2- PCC breaks measured at 24 h after irradiation in all cell lines, and HepG2 was the most susceptible to induction of non-rejoining G2-PCC breaks. A close correlation was found between the clonogenic radiosensitivity and the radiation-induced non-rejoining G2-PCC breaks （r=0.923）. Furthermore, survival-aberration correlations for two or more than two doses lever were also significant. CONCLUSION： The number of non-rejoining G2 PCC breaks holds considerable promise for predicting the radiosensitMty of normal and tumor cells when two or more than two doses lever is tested.
基金supported by the National Natural Science Foundation of China(Grant Nos.11675230 and 11375242)Canada’s Natural Sciences and Engineering Research Council NSERC Discovery GrantCanada Foundation for Innovation CFI
文摘Molecular dynamics simulations are used to investigate the stabilities of C15 Laves phase structures subjected to temperature and point defects. The simulations based on different empirical potentials show that the bulk perfect C15 Laves phase appears to be stable under a critical temperature in a range from 350 K to 450 K, beyond which it becomes disordered and experiences an abrupt decrement of elastic modulus. In the presence of both vacancy and self-interstitial, the bulk C15 Laves phase becomes unstable at room temperature and prefers to transform into an imperfect body centered cubic（BCC）structure containing free vacancies or vacancy clusters. When a C15 cluster is embedded in BCC iron, the annihilation of interstitials occurs due to the presence of the vacancy, while it exhibits a phase transformation into a（1/2） 111 dislocation loop due to the presence of the self-interstitial.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1532261,11690041,and 11675233)
文摘Heavy-ion flux is an important experimental parameter in the ground based single event tests. The flux impact on a single event effect in different memory devices is analyzed by using GEANT4 and TCAD simulation methods. The transient radial track profile depends not only on the linear energy transfer （LET） of the incident ion, but also on the mass and energy of the ion. For the ions with the energies at the Bragg peaks, the radial charge distribution is wider when the ion LET is larger. The results extracted from the GEANT4 and TCAD simulations, together with detailed analysis of the device structure, are presented to demonstrate phenomena observed in the flux related experiment. The analysis shows that the flux effect conclusions drawn from the experiment are intrinsically connected and all indicate the mechanism that the flux effect stems from multiple ion-induced pulses functioning together and relies exquisitely on the specific response of the device.
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It has remained an open problem to accurately compute the partition function of macroscopic systems since the establishment of statistical physics. A rapid method approaching this problem was presented and was strictly tested by molecular dynamic （MD） simulations on Ar atoms in both dense gaseous and liquid states. The outcomes from the method on the internal energy and the work of isothermal expansion （and therefore the free energy） are in good agreement with the MD simulations, suggesting the method would be immediately applied in vast areas.
基金Supported by the National Natural Science Foundation of China under Grant No.19874068the National High Performance Computing Fund.
文摘We have set up an experimental system consisting of an im gun and a Rutherford backscattering spectro-metry(RBS)analysis chamber.Using this system,in situ 2MeV*He+RBS analysis of films is carried out by combination with sputter etching cf low energy Ar+ions.As an example of the sputtering/RBS method,the analysis of three samples,i.e.,Si/(GexSi_(1-x)/Si)/Si(100),WSi_(x)/SiO_(2)/Si and CoSi_(x)/Si,is presented in this paper.After an appropriate fraction of the thick layer is removed by sputtering,the back edge of the Ge peak is separated from Si RBS spectmm on the interface and the O peak of the buried S1O2 layer can be identified.The change cf the doped Ti and W concentrations related to Co on the top surface is observed.The advantages of this analytical method and its possible applications in film are discussed.
基金partly supported by the National Natural Science Foundation of China under Grant Nos.12075288,11735003,and 11961141012。
文摘Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) and Σ^(-) in the timelike region are investigated using the vector-meson dominance model,where the contributions of theρ,ω,and φ mesons are taken into account.The model parameters are determined from the BESⅢexperimental data of the timelike effective form factors|G_(eff)|of the Σ^(+) and Σ^(-) baryons for center-of-mass energies from 2.3864 to 3.02 GeV.It is found that we can provide quantitative descriptions of the available data using as few as one adjustable model parameter.We then progress to an analysis of the electromagnetic form factors in the spacelike region and evaluate the spacelike form factors of the hyperons Σ^(+) and Σ^(-).The electromagnetic form factors obtained for the Σ^(+) and Σ^(-) baryons are comparable with those of other model calculations.
基金supported by the National Key Research and Development Program of China under Grant No.2017YFA0402300
文摘Dielectronic recombination is an important process in high temperature plasmas. In the present work, the KLn （n=L, M, N and O） DR resonance strengths of He-like to O-like xenon ions are measured at the Shanghai electron beam ion trap using a fast electron beam energy scanning method. The experiment uncertainty reaches about 6% with significant improvement of statistics. A relativistic configuration interaction calculation is also made. Theoretical results agree with the experiment results within 15% in most cases.
基金Project supported by the National Magnetic Confinement Fusion Science Program of China(Grant No.2014GB104002)the National Natural Science Foundation of China(Grant No.11647313)+1 种基金the Youth Science and Technology Foundation of Gansu Province,China(Grant No.1606RJYA263)the Institutes of Higher Education Institutions of Gansu Province,China(Grant No.2015B-022)
文摘The head on collision between two opposite propagating solitary waves is studied in the present paper both numerically and analytically.The interesting result is that no phase shift is observed which is different from that found in other branches of physics.It is found that the maximum amplitude in the process of the head on collision is close to the linear sum of two colliding solitary waves.
基金We would like to thank Prof.Zhen Hu for fruitful discussions.This work was supported by the National Natural Science Foundation of China under Grant Nos.11575017,11761141009,11975076,and 11661141008the National Key R&D Program of China under the contract No.2018YFA0403902the CAS Center for Excellence in Particle Physics(CCEPP).
文摘The three lowest-lying r states,ie,r(1S),T(2S),and r(35),composed of b pairs and below the BB threshold,provide a good platform for the researches of hadronic physics and physics beyond the Standard Model.They can be produced directly in ete--colliding experiments,such as CLEO,Babar,and Belle,with low continuum backgrounds.In these experiments,many measurements of the exclusive r(1S)and r(2S)decays into light hadrons,which shed light on the"80%rule"for the Okubo-Zweig-lizuka suppressed decays in the bottomonium sector,were carried out.Meanwhile,many studies of the charmonium and bottomonium productions in r(1S,2S,3S)decays were performed,to distinguish different Quantum Chromodynamics(QCD)models.Besides,exotic states and new physics were also extensively explored in r(1S,2S,3S)decays at CLEO,BaBar,and Bell.The r(1S,2S,3S)states can also be produced in p collisions and in ollisions involving heavy ions.The precision measurements of their cross sections and polarizations at the large hadron collider(LHC),especially in the CMS,ATLAS,and LHCb experiments,help to understand r production mechanisms in Pp collisions.The observation of the sequential r suppession in heavy ion collisions at CMS,LHCb,and ALICE is of great importance for verifying the quark-gluon plasma predicted by QCD.In this article,we review the experimental results on T(1S,2S,3S)at e+e-colliders and the LHC,and summarize their prospects at Belle II and the LHC.
基金National Key Research and Development Program of China(Grants No. 2017YFA0304202 and No. 2017YFA0205700)the NSFC (Grants No. 11 875 231 and No. 11 935 012)the Fundamental Research Funds for the Central Universities through Grant No. 2018FZA3005。
文摘We explore the general characteristics of a matter-wave Sagnac interferometer in a two-parameter estimation scheme. We find that the measurement precisions of both parameters cannot reach the Heisenberg limit(HL) simultaneously when the input state is maximally entangled. Only one of the parameters' uncertainties can approach the HL while the other is scaled by the standard quantum limit.We provide the conditions with which the measurement precision of the specific parameter can reach the HL. We also discuss and figure out the concrete expressions of the constraint conditions for saturating the quantum Cramér–Rao bound. To satisfy these constraint conditions, the evolution time has to be a series of discrete values. Additionally, we calculate the variances of the parameters through some examples under these constraint conditions. The results provided in our work show some intrinsic features of the matter-wave Sagnac interferometer for the two-parameter estimation, which can be valuable in actual experiments.
基金This work has been undertaken with the efidorsement of the IUPAP Commission on Symbols, Units, Nomenclature, Atomic Masses and Fundamental Constants （SUNAMCO）.
文摘This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric （T1/2〉 100 ns） states. All nuclides for which any experimental information is known were considered. NUSASE2016 covers all data published by October 2016 in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2016, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted and critically assessed for their validity and completeness. Furthermore, a large amount of new data and some older experimental results that were missing from ENSDF were compiled, evaluated and included in NUBASE2016. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2016, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclides （TNN） were examined. This approach allowed to estimate values for a range of properties that are labeled in NUBASE2016 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.
文摘This paper is the second part of the new evaluation of atomic masses, AME2012. From the results of a leastsquares calculation, described in Part I, for all accepted experimental data, we derive here tables and graphs to replace those of AME2003. The first table lists atomic masses. It is followed by a table of the influences of data on primary nuclides, a table of separation energies and reaction energies, and finally, a series of graphs of separation and decay energies. The last section in this paper lists all references to the input data used in Part I of this AME2012 and also to the data included in the NUBASE2012 evaluation （first paper in this issue）.
文摘This paper presents the NUBASE2012 evaluation that contains the recommended values for nuclear and decay properties of nuclides in their ground and excited isomeric （T1/2≥ 100 ns） states. All nuclides for which some experimental information is known are considered. NUBASE2012 covers all up to date experimental data published in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2012, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted, and critically assessed of their validity and completeness. Furthermore, a large amount of new and somewhat older experimental results that were missing in ENSDF were compiled, evaluated and included in NUI3ASE2012. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2012, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclei （TNN） were examined. This approach allowed to estimate, whenever possible, values for a range of properties, and are labeled in NUBASE2012 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies that were used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.
基金Supported by National Natural Science Foundation of China(11635003,11025524,11161130520)the National Basic Research Program of China(2010CB832903)the European Commissions 7th Framework Programme(FP7-PEOPLE-2010-IRSES)(269131)
文摘The multinucleon transfer reaction in the collisions of 40 Ca+^124 Sn at Ec.m.= 128.5 MeV is investigated using the improved quantum molecular dynamics model. The measured angular distributions and isotopic distributions of the products are reproduced reasonably well by the calculations. The multinucleon transfer reactions of 40 Ca+^112 Sn, 58 Ni+^112 Sn, 106 Cd+^112 Sn, and 48 Ca+^112 Sn are also studied. This demonstrates that the combinations of neutron-deficient projectile and target are advantageous for the production of exotic neutron-deficient nuclei near N,Z =50. The charged particles’ emission plays an important role at small impact parameters in the de-excitation processes of the system. The production cross sections of the exotic neutron-deficient nuclei in multinucleon transfer reactions are much larger than those measured in the fragmentation and fusion-evaporation reactions. Several new neutron-deficient nuclei can be produced in the 106 Cd+^112 Sn reaction. The corresponding production cross sections for the new neutron-deficient nuclei,101,112 Sb,103 Te,and 106,107) I,are 2.0 nb,4.1 nb,6.5 nb,0.4 μb and 1.0 μb,respectively.
基金the National Natural Science Foundation of China (30730020,90102015)863 project (2006AA100202)Cooperation Project BetweenChina and Greece (2003DFB00034).
文摘The effects of increased intraspecific competition on size hierarchies （size inequality） and reproductive allocation were investigated in populations of the annual plant, spring wheat （Triticurn aestivurn）. A series of densities （100, 300, 1 000, 3 000 and 10 000 plants/m^2） along a gradient of competition intensity were designed in this experiment. The results showed that average shoot biomass decreased with increased density. Reproductive allocation was negatively correlated to Gini coefficient （R^2 = 0.927）, which suggested that reproductive allocation is inclined to decrease as size inequality increases. These results suggest that both vegetative and reproductive structures were significantly affected by intensive competition. However, results also indicated that there were different relationships between plant size and reproductive allocation pattern in different densities. In the lowest density population, lacking competition （100 plants/m^2）, individual reproductive allocation was size independent but, in high density populations （300, 1 000, 3 000 and 10 000 plants/m^2）, where competition occurred, individual reproductive allocation was size dependent： the small proportion of larger individuals were winners in competition and got higher reproductive allocation （lower marginal reproductive allocation; MRA）, and the larger proportion of smaller individuals were suppressed and got lower reproductive allocation （higher MRA）. In conclusion, our results support the prediction that elevated intraspecific competition would result in higher levels of size inequality and decreased reproductive allocation （with a negative relationship between them）. However, deeper analysis indicated that these frequency- and size-dependent reproductive strategies were not evolutionarily stable strategies.
基金Supported by the Key Research Program of the Chinese Academy of Science(XDPB09)the National Natural Science Foundation of China(11890714,11775288,11421505,11520101004)+1 种基金the China Scholarship Council(201704910615)the U.S.Department of Energy,Office of Science(DE-FG02-89ER40531,DE-SC-0012704)
文摘TheΛseparation energy forΛhypernuclei,denoted BΛ,measured in 1967,1968,and 1973 are recalibrated using the current best estimates of the mass of particles and nuclei.The recalibrated BΛare systematically larger(except in the case ofΛ~6He)than the originally published values by about 100 keV.The effect of this level of recalibration is very important for light hypemuclei,especially for the hypertriton.The early BΛvalues measured in1967,1968,and 1973 are widely used in theoretical research,and the new results provide better constraints for the conclusions of such studies.
基金the Na-tional Key Research and Development Program of China(No.2016YFA0400200)the National Natural Science Foundation of China(Nos.11722328,11525313,U1738205,and 11851305)the 100 Talents Program of Chinese Academy of Sciences.
文摘Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.
文摘Ⅰ. INTRODUCTIONMuch work has been done on the modification and phase analysis after N^+ implatation for various carbon content steel, low alloy steel and stainless steel containing low carbon. This article reports the observed modification of 9Cr18 steel after N^+ implatation, and the investigation of the phase variation within the N^+ implantation layer by conversion electron Mssbauer spectroscopy (CEMS)method and X-ray diffraction. Some discussions are also given.
基金Project supported by the National Natural Science Foundation of ChinaChinese Research Association for AtomicMolecular Data
文摘The de-excited spectra of FeI and CuI after the interaction of Fe+ and Cu+ ions with a carbon foil (8.5μg/cm2) have been investigated by using the Beam-foil(BF) technique at an incident energy of 110 keV.The measured lines in the spectra are mainly from de-excited atoms FeI and CuI.The lifetime of stronger lines,including seven lines of FeI and three lines of CuI of the spectra are also measured.Some progress has been made in preparing foils with high quality and in adjusting the intensity of ion beams During measurements,the lifetime of carbon foil targets is more than 30 minutes.
