High-lying excited states in ~(10)Be from the ~9Be(~9Be,~(10)Be)~8Be reaction

A transfer-reaction experiment of ~9Be(~9Be,~(10)Be)~8Be was performed at a beam energy of 45 Me V.Excited states in ~(10)Be up to 18.80 Me V are produced using missing mass and invariant mass methods.Most of the observed high-lying resonant states,reconstructed from theα+~6He and t+~7Li decay channels,agree with the previously reported results.In addition,two new resonances at 15.6 and 18.8 Me V are identified from the present measurement.The 18.55 Me V state is found to decay into both the t + ~7Lig:s: and t + ~7Li?(0.478 MeV) channels, with a relative branching ratio of 0:93 ± 0:33. Further theoretical investigations are encouraged to interpret this new information on cluster structure in neutron-rich light nuclei.     

An Investigation of ~4He+~(12)C and ~4He+~(16)O Reactions Using the Cluster Model

The α-target semimicroscopic single folding potentials have been derived by folding a composite (repul-sive and attractive) effective α-α interaction with the α-cluster distribution density in the target nuclei. The obtained potentials are considered as the real part of the nuclear optical model potentials, while the imaginary parts are phe-nomenologicaly expressed using the Woods-Saxon form. Nine sets of measured experimental data of the 4He+12C and 4 He+16O elastic rainbow scattering over the energy range 80-240 MeV are analyzed using the obtained potentials. The data are successfully reproduced using the extracted potentials. The resulted reaction cross sections are also investigated and compared with the available corresponding data.     

Measurement of the ~2H(~7Be,~6Li)~3He reaction rate and its contribution to the primordial lithium abundance

In the standard Big Bang nucleosynthesis(SBBN) model, the lithium puzzle has attracted intense interest over the past few decades, but still has not been solved. Conventionally, the approach is to include more reactions flowing into or out of lithium, and study the potential effects of those reactions which were not previously considered.~7Be(d,~3He)~6Li is a reaction that not only produces~6Li but also destroys~7Be, which decays to~7Li, thereby affecting~7Li indirectly. Therefore, this reaction could alleviate the lithium discrepancy if its reaction rate is sufficiently high.However, there is not much information available about the~7Be(d,~3He)~6Li reaction rate. In this work, the angular distributions of the~7Be(d,~3He)~6Li reaction are measured at the center of mass energies Ecm = 4.0 Me V and 6.~7Me V with secondary~7Be beams for the first time. The excitation function of the~7Be(d,~3He)~6Li reaction is first calculated with the computer code TALYS and then normalized to the experimental data, then its reaction rate is deduced. A SBBN network calculation is performed to investigate its influence on the~6Li and~7Li abundances. The results show that the~7Be(d,~3He)~6Li reaction has a minimal effect on~6Li and~7Li because of its small reaction rate. Therefore,the~7Be(d,~3He)~6Li reaction is ruled out by this experiment as a means of alleviating the lithium discrepancy.     

Bremsstrahlung neutrino energy loss for ~(24)Mg,~(28)Si,~(32)S,~(40)Ca,~(56)Fe in strong electron screening

Based on Weinberg-Salam theory the bremsstrahlung neutrino energy loss for nuclei 24Mg,28Si,32S,40Ca and 56Fe are investigated in strong electron screening.Our results are compared with those of Dicus' and show that the latter are higher by 2 orders of magnitude in the density-temperature region of 108 g/cm3 ρ/μe 1011 g/cm3 and 2.5 T9 4.5.On the other hand,the factor C shows that the maximum differences are 99.16%,99.13%,99.12%,99.055%,99.040% corresponding to the nuclei 24Mg,28Si,32S,40Ca and 56Fe.     

Langevin study of neutron emission in the reactions ^16O＋^181Ta and ^19F＋^178Hf^＊

The pre-scission neutrons measured in the reactions 16O 181Ta and 19F 178Hf are studied via a Langevin equation coupled with a statistical decay model. We find that because of the mass asymmetry of different entrance channels, the spin distributions of compound nuclei would be different, consequently, the measured neutrons in these two reactions would also different. This means that the entrance channel will affect the particle emission in the fission process of hot nuclei.     

Bremsstrahlung neutrino energy loss for ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca, ~(56)Fe in strong electron screening

Based on WeinbergoSalam theory the bremsstrahlung neutrino energy loss for nuclei ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca and ~(56)Fe are investigated in strong electron screening. Our results are compared with those of Dicus' and show that the latter are higher by 2 orders of magnitude in the density-temperature region of 10~8 g/cm~3 ≤ρ/μ_e≤10~(11) g/cm~3 and 2.5 ≤ T_9 ≤4.5. On the other hand, the factor C shows that the maximum differences are 99.16%, 99.13%, 99.12%, 99.055%, 99.040% corresponding to the nuclei ~(24)Mg, ~(28)Si, ~(32)S, ~(40)Ca and ~(56)Fe.     

Simulation of the fission dynamics of the excited compound nuclei ~(206)Po and ~(168)Yb produced in the reactions ~(12)C+~(194)Pt and ~(18)O+~(150)Sm

A two-dimensional dynamical model based on the Langevin equation was used to study the fission dynamics of the compound nuclei ~(206)Po and ~(168)Yb produced in the reactions ~(12)C+~(194)Pt and ~(18)O+~(150)Sm,respectively.The fission cross section and average pre-scission neutron multiplicity were calculated for the compound nuclei ~(206)Po and ~(168)Yb,and results of the calculations compared with the experimental data.The elongation coordinate was used as the first dimension and the projection of the total spin of the compound nucleus onto the symmetry axis,K,considered as the second dimension in the Langevin dynamical calculations.In the two-dimensional calculations,a constant dissipation coefficient of K and a non-constant dissipation coefficient have been used to reproduce the abovementioned experimental data.It is shown that the two-dimensional Langevin equation can satisfactorily reproduce the fission cross section and average pre-scission neutron multiplicity for the compound nuclei ~(206)Po and ~(168)Yb by using constant values of the dissipation coefficient of K equal to γκ=0.18(MeV zs)~(-1/2) and γκ= 0.20(MeV zs)~(-1/2)for the compound nuclei ~(206)Po and ~(168)Yb,respectively.     

Study of ~3He inelastic scattering on ~(13)C and ~(14)C at 37.9 MeV

The differential cross sections of elastic and inelastic scattering of ³He ions on ¹³C and ¹⁴C have been studied at an energy of 37.9 MeV with a double folding model based on M3Y-Reid effective nucleon-nucleon interaction. The resulted parameters have been used for the standard Distorted Wave Born Approximation calculations of angular distributions corresponding to different excitations levels of ¹³C and ¹⁴C and deformation parameters have been deduced.     

Strong Decays of Charm Mesons D_1~*(2680), D_3~*(2760), D_2~*(3000)

In this article, we assign the higher charm mesons D1_*(2680), D3_*(2760) and D2_*(3000) to be the 2S 1~-, 1D3~- and 1F 2~+ states, respectively, and study the two-body strong decays to the ground state charm mesons and light pseudoscalar mesons with the heavy meson effective theory. We obtain the ratios among the strong decays, which can be confronted to the experimental data in the future and shed light on the nature of those higher charm mesons.     

Reanalysis of Elastic Scattering of ~6Li + ~(209)Bi Reaction Using a New DensityDistribution of ~6Li Nucleus

In the present paper, the elastic scattering of6 Li + 209 Bi system is reanalyzed by using the double folding model (DFM) at energies near the Coulomb barrier (ELab=29.9 and 32.8 MeV). With this goal, a new density distribution of6 Li nucleus, the no-core full configuration (NCFC) density distribution (DD), is used to obtain the real potentials in DFM calculations. The NCFC DD results are compared with the results of both gaussian shape (GS) DD and an earlier study as well as the experimental data. This comparison provides information about the similarities and differences of the models used in calculations.     

Experimental research into the two-proton emissions from ~(17,18) Ne,~(28) P and ~(28,29)S

Two-proton emissions from the excited states of 17,18Ne, 28P and 28,29S were investigated experimentally by the radioactive beams bombarding on the 197Au target via the Coulomb excitation. The complete-kinematics measurements were actualized by the stacks of silicon-strip detectors and CsI+PIN array detectors. The invariant mass of final systems as well as the relative momentum, opening angle, and relative energy of the two emitted protons was reconstructed under the framework of relativ istic kinematics. V...     

植物油的1H NMR和13C NMR的测定

油酸和亚油酸,是人体必需的营养成份,具有抗癌,防止动脉硬化,降脂减压等作用,因而它们在治疗一些癌症及减肥降血脂等方面取得了较好的疗效^[1-3]。通常油酸,亚油酸和其他脂肪酸以甘油酯的形式,大量地存在于植物油中。本文用¹H NMR测定了5种植物油各组峰面积积分,按文献[4]扣除法,整理了各组峰的积分值,计算出油脂中每摩尔所含各功能团的个数,不饱和度,酯化度等数据。此外,还记了豆油和茶油的¹³C NMR谱,从这两种谱图相关谱线积分值推算出各功能团与甲基基团的比率与¹H NMR谱所得结果接近。并计算出,上述两种油中所含脂肪酸甘油酯和各种不饱和脂肪酸甘油酯的克分子百分数。对测得CCH₂C基团质子自旋晶格弛豫时间T₁进行分析后,给出一经验公式来予以拟合,计算结果与测定值吻合。这一事实说明,油脂中各种组分克分子百分数的计算是可以信赖的。     

Fragment distribution in ~(78,86)Kr+~(181)Ta reactions

Within the framework of the isospin-dependent quantum molecular dynamics model, along with the GEMINI model, the ~(86)Kr+~(181)Ta reaction at 80, 120 and 160 MeV/nucleon and the ~(78)Kr+~(181)Ta reaction at 160 MeV/nucleon are studied, and the production cross sections of the generated fragments are calculated. More intermediate and large mass fragments can be produced in the reactions with a large range of impact parameter. The production cross sections of nuclei such as the isotopes of Si and P generally decrease with increasing incident energy.Isotopes near the neutron drip line are produced more in the neutron-rich system ~(86)Kr+~(181)Ta.     

X(3872) and Bound State Problem of D~0(D)*~0((D)~0D*~0)

We have performed a dynamical calculation of the bound state problem of D~0(D)~(*0) by considering the pion and sigma meson exchange potential.Our preliminary analysis disfavors the molecular interpretation of X(3872) if we use the experimental D~* Dπ coupling constant g=0.59 and a reasonable cutoff around 1 GeV,which is the typical hadronic scale.In contrast,there probably exists a loosely bound S-wave B (-B)~* molecular state.Such a molecular state would be rather stable since its dominant decay mode is the radiative decay through B~*→Bγ.     

Screening effects on ~(12)C+~(12)C fusion reaction

One of the important reactions for nucleosynthesis in the carbon burning phase in high-mass stars is the ~(12)C+~(12)C fusion reaction. In this study, we investigate the influences of the nuclear potentials and screening effect on astrophysically interesting ~(12)C+~(12)C fusion reaction observables at sub-barrier energies by using the microscopic α-αdouble folding cluster(DFC) potential and the proximity potential. In order to model the screening effects on the experimental data, a more general exponential cosine screened Coulomb(MGECSC) potential including Debye and quantum plasma cases has been considered in the calculations for the ~(12)C+~(12)C fusion reaction. In the calculations of the reaction observables, the semi-classical Wentzel-Kramers-Brillouin(WKB) approach and coupled channel(CC)formalism have been used. Moreover, in order to investigate how the potentials between ~(12)C nuclei produce molecular cluster states of ~(24)Mg, the normalized resonant energy states of ~(24)Mg cluster bands have been calculated for the DFC potential. By analyzing the results produced from the fusion of ~(12)C+~(12)C, it is found that taking into account the screening effects in terms of MGECSC is important for explaining the ~(12)C+~(12)C fusion data, and the microscopic DFC potential is better than the proximity potential in explaining the experimental data, also considering that clustering is dominant for the structure of the ~(24)Mg nucleus.     

Entrance-channel dynamics in the reaction ~(40)Ca+~(208)Pb

The entrance-channel dynamics including capture, fusion, and quasifission processes for the reaction ~(40)Ca+~(208)Pb is investigated in the fully microscopic time-dependent Hartree-Fock(TDHF) theory. The calculations are performed in three-dimensional Cartesian coordinate without any symmetry restrictions, in which the full Skyrme energy functional SLy4d and SLy5 are adopted.We study the energy dependence of capture cross sections, and find that the experimental data are well reproduced by the TDHF calculations. Both fusion and quasifission events are observed in the reaction ~(40)Ca+~(208)Pb. The contact time, mass and charge of quasifission fragments show a wide distribution in SLy4d compared with SLy5, implying that more nucleons are transferred in the SLy4d calculations. We find that the total kinetic energy of quasifission fragments in the TDHF calculations is distributed around Viola systematics, indicating that most of the relative kinetic energy is dissipated in quasifission dynamics.     

~(13)C—~1H基团弛豫过程的双指数特性

本文从理论和实验上研究了在碳氢基团中~(13)C和质子弛像过程的相互影响。     

螺吲哚啉萘并噁嗪衍生物的￣1H、￣（13）C NMR谱法研究

本文报道了１－１８烷基－３，３－二甲基螺吲哚啉萘并嗪及其５＇－ＣＯＯＭｅ，８＇－Ｂｒ衍生物在氯仿和四氯化碳中的￣１Ｈ和￣（１３）ＣＮＭＲ结构特征。     

CDCC calculations of fusion of ~6Li with targets ~(144)Sm and ~(154)Sm:effect of resonance states

Continuum Discretized Coupled-Channel(CDCC) model calculations of total, complete and incomplete fusion cross sections for reactions of the weakly bound ~6Li with ~(144,154)Sm targets at energies around the Coulomb barrier are presented. In the cluster structure frame of ~6Li→α+d, short-range absorption potentials are considered for the interactions between the ground state of the projectile ~6Li and α-d fragments with the target. In order to separately calculate complete and incomplete fusion and to reduce double-counting, the corresponding absorption potentials are chosen to be of different range. Couplings to low-lying excited states 2~+, 3~-of ~(144)Sm and 2~+, 4~+ of ~(154)Sm are included. So, the effect on total fusion from the excited states of the target is investigated. Similarly, the effect on fusion due to couplings to resonance breakup states of ~6Li, namely, l = 2,J~π= 3~+, 2~+, 1~+ is also calculated.The latter effect is determined by using two approaches,(a) by considering only resonance state couplings and(b)by omitting these states from the full discretized energy space. Among other things, it is found that both resonance and non-resonance continuum breakup couplings produce fusion suppression at all the energies considered.     

Applicability of ~9Be global optical potential to reactions of ~(7,10,11,12)Be

Elastic scattering angular distributions and total reaction cross-sections of ~(7,10,11,12)Be projectiles are predicted by the systematic ~9 Be global phenomenological optical model potential for target mass numbers ranging from24 to 209. These predictions provide a detailed analysis by their comparison with the available experimental data.Furthermore, these elastic scattering observables are also predicted for some targets out of the mass number range.The results are in reasonable agreement with the existing experimental data, and they are presented in this study.