Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a Ca-54 beam striking on a liquid hydrogen target at similar to 200 MeV/u. A ...significantly larger cross section to the p(3/2), state compared to the f(5/2) state observed in the excitation of Ca-53 provides direct evidence for the nature of the N = 34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.
Twenty-one two-proton knockout (p , 3p) cross sections were measured from neutron-rich nuclei at ∼ 250 MeV /nucleon in inverse kinematics. The angular distribution of the three emitted protons was ...determined for the first time, demonstrating that the (p, 3p) kinematics are consistent with two sequential proton-proton collisions within the projectile nucleus. Ratios of (p , 3p) over (p, 2p) inclusive cross sections follow the trend of other many-nucleon removal reactions, further reinforcing the sequential nature of (p, 3p) in neutron-rich nuclei.
A novel photonic technique for microwave frequency measurement utilizing dispersion in a multichannel chirped fiber Bragg grating is presented. The technique is based on the amplitude comparison of ...power fading functions generated by double sideband modulated optical carriers propagating through a dispersive medium
This paper presents the harmonic torque reduction by the different rotor pole angles of a three-phase 12/8 switched reluctance motor via an analytical model and simulation method. Improving torque ...performance by stator and rotor angles was applied for three-phase switched reluctance motor at stator pole/rotor pole ratios of 6/4, 8/12, 18/12, and 24/18. The average torque and the torque ripple effect by stator and rotor pole embrace have been recently studied in many projects. Due to the fact that leakage flux, flux density, and inductance are affected by the stator and rotor pole angles non-linear and linear leakage flux curves occur. Many stator and rotor pole angle combinations for the three-phase switched reluctance motor have already been done via a finite element method. In this paper, turn-on and turn-off angles will be figured based on stator and rotor pole embraces.
The one-neutron knockout from 52Ca in inverse kinematics onto a proton target was performed at ∼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to ...bound states in 51Ca and the momentum distributions corresponding to the removal of 1f7/2 and 2p3/2 neutrons were measured. The cross sections, interpreted within the distorted-wave impulse approximation reaction framework, are consistent with a shell closure at the neutron number N=32, found as strong as at N=28 and N=34 in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 1f7/2 and 2p3/2 orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the 2p3/2 orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
The present work reported the one-pot preparation of silver nanoparticles doped with graphene oxide (Ag@GO), using glucose as an eco-friendly reducing agent. The effects of synthesis conditions on ...the introduction of AgNPs onto graphene oxide sheets were confirmed by modern analytical techniques and antibacterial assays. Results showed that the Ag@GO-4 sample prepared with glucose:AgNO3:GO mass ratio of 1:1:1 at 60 °C for 60 min exhibited an appropriate one for further studies with AgNPs sizing of 16.66 ± 3.73 nm. The Ag@GO-4 effectively inhibited the development of S. enterica, P. aeruginosa, and S. aureus with the 50 % inhibitory concentration at 14.5, 0.9, and 6.8 μg/mL, respectively. The simultaneous effects of Ag@GO concentration, pH, interaction time, annealing temperature, and bacterial density on the antibacterial activity of Ag@GO-4 were also investigated by Plackett-Burman and Box-Behnken design. The optimal values deducing for Ag@GO-4 concentration, pH, and bacterial density were 40 μg/mL, 5.5, and 5.1 × 106 CFU/mL, respectively, which could impressively reach 99.99 % of S. enterica elimination in practice. The interaction time and annealing temperature implied a negligible effect on the antibacterial activity of Ag@GO-4. All results of the present study affirmed the future use of Ag@GO not only as an efficient antibacterial agent but also potentially as a novel anti-virus method of treatment.
Display omitted
•Sufficient synthetic condition silver nanoparticles doped with graphene oxide (Ag@GO) nanocomposite were precisely investigated.•Antibacterial performance were studied via Placket-Burman and Box-Behnken designs.•Free radicals possessed an impressive effect on the activity of Ag@GO.•Ag@GO is foreseen to play a vital role in antivirus treatment.
The first γ-ray spectroscopy of 52Ar, with the neutron number N = 34, was measured using the 53K(p, 2p) one-proton removal reaction at ~210 MeV/u at the RIBF facility. The 2+1 excitation energy is ...found at 1656(18) keV, the highest among the Ar isotopes with N > 20. This result is the first experimental signature of the persistence of the N = 34 subshell closure beyond 54Ca, i.e., below the magic proton number Z = 20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 2+1 systematics of neutron-rich Ar isotopes, and support a N = 34 subshell closure in 52Ar.
PDF
