Spin structure of the “forward” charge-exchange reaction n + p → p + n and deuteron charge-exchange breakup d + p → (pp) + n

The spin structure of the nucleon charge-exchange process n + p → p + n is investigated. Analysis shows that the spin-dependent part of the differential cross section of the process n + p → p + n at zero angle, which is proportional to the differential cross section of the deuteron charge-exchange breakup d + p → (pp) + n in the “forward” direction, plays the predominant role in the wide range of neutron momenta.     

Density Functional Study of Cationic and Anionic Ag_mCu_n (m + n ≤ 5) Clusters

The structural and energetic properties of bimetallic Ag m Cu n clusters (m + n ≤ 5) in the cationic and anionic charged states have been investigated by density functional theory with relativistic effective core potentails.The stable cationic pentamers have three-dimensional structures in contrast to anionic clusters assume planar structures.For the given cluster size the electron affinities decrease as the Cu content increases,while no clear trend can be found in adiabatic ionization potentials.The binding energy per atom also increases with the increasing Cu content and follows the order anion cation.The most probable dissociation channels of the clusters considered are also discussed.     

Complexation of hydrogen by lithium: structures,energies and vibrational spectra of Li+ (H2) n (n = 1–4), Li-H(H2) m and Li-H + (H2) m (m = 1–3)

The interaction of metals with hydrogen is of importance in several areas of technology. Lithium-hydrogen complexes are particularly amenable to theoretical study. Although no stable compound of the Li atom and H₂ has been found, a weak dative interaction forms between the σ bond of H₂ and the positively charged Li atom for Li⁺, Li-H⁺, and Li-H. At least four H₂ molecules can be complexed by Li⁺, and three by Li-H⁺ and Li-H. The presence of the Li ion does not substantially weaken the H₂ bond, nor is the energy of dissociation affected; however, the Li ion does form stable complexes with the dissociated H atoms.     

Description of the gamov-teller β+-decays and (n,p) transitions in spherical nuclei

The results of calculations of the total log (t)-quantities for decays of neutron-deficit nuclei and strength functions of (n, p) transitions are presented. It is shown that in spherical nuclei the ¦g _A/g _V¦1·0 conditions hold for the constants of a weak interaction.Dedicated to the memory of M. Gmitro.     

Cyclic Representation of the gl√q (n)-Covariant Oscillator Algebra

The cyclic representation ofgl_q (n)-covariant oscillator algebrais discussed by use of some noncommutating cyclicvariables.     

Measurement of PV asymmetry in +p→d+γ and ■+d→n+p

The measurement of parity-violating (PV) observables in few-nucleon system can shed light on our current understanding of the weak interaction between nucleons.Theoretical models describe the nucleonnucleon weak interaction at low energies use a series of undetermined parameters.Two parity violating measurements have been considered: the capture of polarized slow neutrons on hydrogen (n + p → d + γ) at Los Alamos National Laboratory for first phase and Oka Ridge National Laboratory for second phase and the helicity dependence of the deuteron photodisintegration cross section using circularly polarized photons (γ + d → n + p) at Shanghai Institute of Applied Physics.The goal of both experiments is to constraint the weak meson-nucleon couplings to a precision of 1 ×10-8 .The introduction of both experiments is presented.     

Measurements of π+p,K+p and pp elastic scattering)

The paper presents the results on differential cross sections for elastic scattering of 7⁺-, K⁺-mesons and protons on protons in the 4-momentum transfer squared range 0·08 ¦t¦ 1·0 (GeV/c)² and incident particle momentum of 29 and 43 GeV/c for pions and kaons and 29, 43, 50 and 65 GeV/c for protons. The measurements were taken with the spectrometer Sigma, installed in the positive beam of the IHEP accelerator.Presented by F. A. Yotch at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.The authors would like to express their gratitude to A. A.Logunov, Yu. D.Prokoshkin, L. D.Soloviev and V. A.Yarba for their support of this experiment. We are indebted to CERN Administration for giving us a permission to use a part of equipment of the CIBS spectrometer and to W.Kienzle for useful discussions.     

Invariance of Painlev property for some reduced (1+1)-dimensional equations

We study the Painleve′property of the (1+1)-dimensional equations arising from the symmetry reduction for the (2+1)-dimensional ones.Firstly,we derive the similarity reduction of the (2+1)-dimensional potential Calogero–Bogoyavlenskii–Schiff (CBS)equation and Konopelchenko–Dubrovsky (KD)equations with the optimal system of the admitted onedimensional subalgebras.Secondly,by analyzing the reduced CBS,KD,and Burgers equations with Painleve′test,respectively,we find both the Painleve′integrability,and the number and location of resonance points are invariant,if the similarity variables include all of the independent variables.     

Measurement of PV asymmetry in(→n)+p→d+γ and (→γ)+d→n+p

The measurement of parity-violating(PV)observables in few-nucleon system can shed light on our current understanding of the week interaction between nucleons.Theoretical models describe the nucleonnucleon weak interaction at low energies use a series of undetermined parameters.Two parity violating measurements have been considered: the capture of polarized slow neutrons on hydrogen((n)+p→d+γ)at Los Alamos National Laboratory for first phase and Oka Ridge National Laboratory for second phase and the helicity dependence of the deuteron photodisintegration cross section using circularly polarized photons((γ)+d→n+p*)at Shanghai Institute of Applied Physics.The goal of both experiments is to constraint the weak meson-nucleon couplings to a precision of 1 × 10-8.The introduction of both experiments is presented.     

Synthesis and characterization of layered perovskite oxides (La, Sr) n + 1(Ti, Cr) n O3n + 1 (n = 1, 2)

We report here the synthesis of layered perovskite oxides of the composition La_0.5Sr_1.5Ti_0.5Cr_0.5O₄ and LaSr₂TiCrO₇ by conventional solid-state reaction method. Results of XRD analysis show that the phases crystallize with tetragonal unit cell in the space group I4/mmm. Both phases behave as insulators and the linearity of log ρ versus T ^?1/4 plot in the temperature range 150–350 K suggests that the electronic conduction occurs by Mott’s variable range hopping mechanism. The antiferromagnetic interactions observed for the samples arise from Cr³⁺–O–Cr³⁺ superexchange interaction.     

Structure and stability of SiBn+ AND CBn+ (n = 1–4)

The structures and binding energies of small boron-rich clusters are studied using correlated wave functions and polarization basis sets. Carbon is the central atom in CB_n⁺, while SiB_n⁺ prefers planar boron networks with silicon as one of the edge atoms. These ground state structures can be explained by differences in the electronegativities of the component elements. The various fragmentation channels of SiB_n⁺ are also examined using binding energy differences.     

Synthesis and Characterization of Terpolymers of poly(L-lactide-glycolide-ε-caprolactone)

Random terpolymers of poly(L-lactide-glycolide-ε-caprolactone) (PLLGC) was prepared by ring-opening polymerization of L-lactide, glycolide and ε-caprolactone monomers initiated with stannous octanoate. Fourier transform infrared spectra, nuclear magnetic resonance and gel permeation chromatography were employed to characterize the obtained PLLGC terpolymers. The effects of polymerization temperature, reaction time, the amount of initiator and the polymerization pressure on the weight average molecular mass and polydispersity index of the PLLGC were investigated. In addition, the water contact angle of the PLLGC was also tested. The characterization of chemical structure showed that the PLLGC was successfully synthesized. For instance, a PLLGC terpolymer with a weight average molecular mass of about 12.435?×?10⁴?Da and a polydispersity index of 1.28 was obtained when the polymerization was conducted with a molar ratio of monomer to initiator ([M]/[I]) of 2000, polymerization temperature of 140?°C, polymerization pressure of 5.0?Pa and reaction time of 24?h. The random incorporation of ε-CL monomer units decreased the wettability of the PLGA copolymers.     

Energy and angular distributions of deuterons from the D + D → p + n + d reaction

The energy and angular distributions of deuterons from the D + D → p + n + d reaction are experimentally and theoretically studied. The experiment is conducted on the U-240 cyclotron at the Institute for Nuclear Research in an extracted beam of deuterons with energy E _D = 36.9 MeV. A theoretical analysis has been performed using the microscopic diffraction nuclear model, within which the final-state interaction is considered and simple expressions for internal wave functions and approximations that include quasibinary mechanisms are employed.     

~(100)Mo(n,2n)~(99)Mo,~(96)Mo(n,p)~(96)Nb和~(92)Mo(n,α)~(89m+g)Zr反应截面测量

本文报告了在E_n=13.40—14.79MeV中子能区用活化法以~(27)Al(n,α)~(24)Na截面为中子注量标准测得的~(100)Mo(n,2n)~(99)Mo,~(96)Mo(n,p)~(96)Nb和~(92)Mo(n,α)~(89m+g)Zr的反应截面,中子能量是用铌锆截面比法测定的。文中将实验测量值与理论计算值进行了比较,还对上述三个反应的截面进行了编评,给出了推荐的激发曲线。     

Effect of violating t-invariance of the electromagnetic interaction of hadrons in the processes n + p → d + γ and n + → d + e++e−

T-odd correlations that are possible in the processes n + p d + and n + p d + e⁺ + e^e- and that arise due to the capture of thermal neutrons are determined in terms of threshold amplitudes (for the process n + p d + @#@) or electromagnetic inelastic form factors (for the process n + p d+ e⁺ + e^e§-). The mechanism of these reactions is not given in concrete form, but those general properties of the electromagnetic hadronic current are used that are preserved with three-dimensional reflections.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 8–13, October, 1986.