Nuclear structure of proton-rich unstable nucleus 28P studied by g-factor measurement*

Nuclear structure of proton-rich unstable nucleus 28P has been studied by measuring its g-factor for the first time. The g-factor of 28P (Iπ =3+, T1/2=270.3 ms) was measured by means of β-NMR technique combined with the new polarization technique for charge exchange reaction product in the intermediate energy heavy ion collisions. The obtained g-factor of g=0.1028(27) is very much quenched from the Schmidt value,but is well reproduced by the shell model (+0.102). In connection with the magnetic moment of the mirror partner and the β-ray transition probability, the orbital angular momenta and intrinsic spins of protons and neutrons have been determined as 〈lp〉 = 0.43(29), 〈ln〉 = 1.85(29), 〈Sp〉 = 0.28(4), and 〈Sn〉 = 0.44(4).     

A dynamical systems model of intrauterine fetal growth

ABSTRACT

The underlying mechanisms for how maternal perinatal obesity and intrauterine environment influence foetal development are not well understood and thus require further understanding. In this paper, energy balance concepts are used to develop a comprehensive dynamical systems model for foetal growth that illustrates how maternal factors (energy intake and physical activity) influence foetal weight and related components (fat mass, fat-free mass, and placental volume) over time. The model is estimated from intensive measurements of foetal weight and placental volume obtained as part of Healthy Mom Zone (HMZ), a novel intervention for managing gestational weight gain in obese/overweight women. The overall result of the modelling procedure is a parsimonious system of equations that reliably predicts foetal weight gain and birth weight based on a sensible number of assessments. This model can inform clinical care recommendations as well as how adaptive interventions, such as HMZ, can influence foetal growth and birth outcomes.     

NMR on short-lived beta-emitter43Ti using new fragment separator at LBL

The lifetime and magnetic moment of⁴³Ti (I^π-7/2⁻, T_1/2=0.50 sec), one of the mirror beta-radioactive nuclei in the f_7/2-shell, have been measured with a fragment separator built at the Bevalac of the LBL. By means of the beta-NMR method on⁴³Ti, a preliminary value of the magnetic moment of⁴³Ti was determined to be μ=(0.70±0.07) μ_π.     

Longitudinal flow of protons from (2-8)A GeV central Au+Au collisions

Rapidity distributions of protons from central 197Au+197Au collisions measured by the E895 Collaboration in the energy range from (2-8)A GeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion are extracted from these distributions. The results show an approximately linear increase in the longitudinal flow velocity, (L), as a function of the logarithm of beam energy.     

The use of infrared probes in solvation studies: Acetone in mixed protic-aprotic solvents

Infrared spectra ot acetone in the CO stretching region have been studied as a function of the composition of a range of mixed protic-aprotic solvents. For methanolic systems, equilibria between hydrogen-bonded and non hydrogen-bonded acetone dominate the spectral changes, but for aqueous systems at least four distinct components need to be considered.     

Polarization of 23Ne, 24m,25Al and 28P produced through single nucleon pickup and charge-exchange reactions at 100 AMeV

We measured the polarization of the $\upbeta $ -emitting ²³Ne (I ^π ?= 5/2^?+?, T _1/2?= 37.24 s) and ²⁵Al(I ^π ?= 5/2^?+?, T _1/2?= 7.18 s) produced through the one nucleon pickup reactions and ^24mAl(I ^π ?= 1^?+?, T _1/2?= 131 ms, E _ex?= 426 keV) and ²⁸P(I ^π ?= 3^?+?, T _1/2?= 270 ms) produced through charge-exchange reactions in the intermediate energy heavy ion collisions. We compared them with those from the projectile fragmentation process. The larger polarization seems to persistently be positive throughout the momentum distribution, and sharper momentum distributions suggest that nuclear friction mechanism is responsible for the polarization phenomena.     

The structure of the radical cation of ethylene oxide (oxirane) in low-temperature matrices

Based on analysis of ESR spectra, it is suggested that the initial species formed by electron loss from oxirane (¹³C) in CFCl₃ at 77 K is the ring-closed o(n) radical, rather than the ring-opened “allylic” radical.     

Hyperfine interactions of 19O in TiO2 and quadrupole moments of 13,19O

The electric quadrupole interaction of ¹⁹O(I^π=(5/2)⁺, T_1/2=27.0 s) in TiO₂ single crystal was studied in detail by means of the β-NQR to determine the electric quadrupole moments Q of short-lived β-emitting nuclei ¹⁹O and ¹³O(I^π=(3/2)^-, T_1/2=8.6 ms). Two implantation sites were found for the implanted O nucleus and the quadrupole coupling constants of ¹⁹O at these sites were determined. We observed FT-NMR of the enriched stable isotope ¹⁷O in TiO₂ and obtained the electric field gradient (EFG) at the oxygen substitutional site. With this knowledge, we have determined Q(¹³O)=11.0 ± 1.3 mb and Q(¹⁹O)=3.7 ± 0.4 mb. The present results are compared with the theoretical values calculated by the shell model code, OXBASH and by the Hartree–Fock calculation with the realistic potential. This revised version was published online in August 2006 with corrections to the Cover Date.     

Knight shifts for short-lived β emitters in Pt

The Knight shifts K for short-lived β emitters ¹²N and ²⁷Si implanted in Pt have been measured by means of β-NMR technique. The results were K(¹²N in Pt)= +(5.8 ± 2.1)× 10^-4 and K(²⁷Si in Pt)= +(1.4 ± 0.8)× 10^-3. The spin–lattice relaxation time T₁ was measured for ¹²N in Pt. The result was T₁(¹²N in Pt, T=300 K)= 66 ± 8 ms, thus, T₁T= 20 ± 2 Ks. The present Knight shifts are in good agreement with the KKR band structure calculation with local lattice relaxation determined theoretically. This revised version was published online in August 2006 with corrections to the Cover Date.     

Zur ann?hernden Bestimmung von Harzim Ceresin

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