Development of β-NMR and β-NQR

The β-NMR (nuclear magnetic resonance) and β-NQR (nuclear quadrupole resonance) technique and its ex-perimental set-up have been developed for the first time in China. The lifetime, magnetic moment and spin polarization of ^12B were determ/ned. The experimental results show the reliability of this newly developed β-NMR and β-NQR set-up.     

Anti-proton scheme of β-disintegration

The author considers the possibility of generalizing known schemes of-decay by means of the anti-proton reaction.     

Combinatorial chemistry of β-hairpins

Combinatorial chemistry is expanding rapidly both in terms of chemistry development and application to the synthesis of compound libraries for lead discovery and optimization. Combinatorial technologies continue evolving and developing, in fact they are being used as basic research tools in different fields that include peptide/protein folding. This review examines the use of combinatorial chemistry in the design of peptides and protein domains that adopt beta-sheet conformations. In particular, the use of conformationally restricted peptide libraries has allowed the identification of linear peptides that are folded in a beta-hairpin structure in plain aqueous solutions.     

Simple Formula of β+-Decay Half-Lives of Nuclei Far From β-Stable Line

We generalize the formula of β⁺-decay half-lives [Phys. Rev. C 73 (2006) 014305] to include all available data of nuclei far from the β-stable line. Good agreement with experimental data is obtained by taking into account the even-odd (e-o) effect. It is shown that the e-o effect on β⁺-decay half-life is apparent for the allowed β⁺-transition, whereas it is not apparent for the first and second forbidden transitions. This demonstrates that the allowed β⁺-transition is more sensitive to the nuclear even-odd effect than the forbidden β⁺-transition. The underlying physics is discussed. This formula can be used to predict the β⁺-decay half-lives of the nuclei far from β-stability. It is useful to experimental physicists for analyzing the data of β⁺-decay.     

Solvent complexes of jet-cooled β-phenylethylamine

Laser-induced fluorescence spectroscopy was used to investigate -phenylethylamine molecules that were cooled via supersonic gas expansions. The bare molecule spectra reveal 0-0 transitions that can be attributed to four separate conformers. Upon the addition of water or alcohol solvents, a series of new peaks is induced that appear to be built off separate bare molecule transitions. This is a pattern that is markedly different from the one seen for solvent addition to tyramine, which includes an-OH in the para position. As a result, definite hypotheses can be made to explain the influence of the para-OH in affecting solvent induced conformations.     

Semi-gross theory of nuclear β-decay

The gross theory of β-decay is refined to take into account shell effects of the parent nuclei, and the resulting theory is named semi-gross theory. In this theory, the one-particle energy distribution in the parent nucleus is taken to have structures, and the one-particle strength function is assumed to depend on the quantum numbers of the initial state of the decaying nucleon. β-decay (partial) half-lives are calculated for 1659 nuclides, and the results are compared with experimental data as well as with those calculated by the gross theory. The β-decay strength functions are shown for two selected nuclides, and briefly discussed. These numerical studies confirm that the semi-gross theory includes some part of the shell effects correctly, although there still remain deviations of the theoretical results from experimental data, which should, at least partly, be due to shell effects of the daughter nuclei. Comparison of the present results with microscopic theories shows that the overall accuracy of the semi-gross theory is comparable with those of the microscopic theories.     

First-principles investigation of the phonon spectrum of β-GaS

This paper presents the results of the first-principles density functional theory calculation of the phonon spectrum of the ??-GaS semiconductor with a layered structure. The elastic constants and velocities of sound along and across the layers of the ??-GaS semiconductor have been determined. Investigation of the equilibrium structure and the phonon spectrum of the (0001) surface of the ??-GaS crystals has demonstrated that the bulk and surface structural and dynamical properties of these crystals differ only slightly. The calculated frequencies and symmetries of phonon modes at the center of the Brillouin zone of the semiconductor are in satisfactory agreement with the experimental data obtained from the Raman and infrared spectra.     

Calculations of the β-decay half-lives of neutron-deficient nuclei

In this work,β~+/EC decays of some medium-mass nuclei are investigated within the extended quasiparticle random-phase approximation(QRPA),where neutron-neutron,proton-proton and neutron-proton(np) pairing correlations are taken into consideration in the specialized Hartree-Fock-Bogoliubov(HFB) transformation.In addition to the pairing interaction,the Br¨uckner G-matrix obtained with the charge-dependent Bonn nucleon-nucleon force is used for the residual particle-particle and particle-hole interactions.Calculations are performed for even-even proton-rich isotopes ranging from Z =24 to Z =34.It is found that the np pairing interaction plays a significant role inβ-decay for some nuclei far from stability.Compared with other theoretical calculations,our calculations show good agreement with the available experimental data.Predictions of β-decay half-lives for some very neutron-deficient nuclei are made for reference.     

Edge Scaling of the β-Jacobi Ensemble

We study the scaling limit of the spectrum of the ??-Jacobi ensemble at the soft edge and hard edge for general values of ??. We show that the limiting point processes correspond respectively to the stochastic Airy and Bessel point processes introduced in Ramírez et al. (J. Am. Math. Soc. 24(4):919?C944, 2011) and Ramírez and Rider (Commun. Math. Phys. 288(3):887?C906, 2009).     

Properties of the β-Delayed Proton Decay of 147Er

The β-delayed proton decay of 147Er is studied experimentally using the 58 Ni＋92Mo reaction at a beam energy of 383 MeV. Based on a He-jet apparatus coupled with a tape transport system, the β-delayed proton radioactivities both from the vδl/2 ground state and the vh11/2 isomer in 147 Er are identified by proton-7 coincidence measurements. By analyzing the time distribution of the 4＋ → 2＋-γ transition in the grand-daughter nucleus 146Dy, a half-life of 1.6 ± 0.2s is determined for the Vh11/2 isomer in 147 Er. The half-life for the ground state of 147Er is estimated to be 3.2±1.2 s.     

Systematical law of β+-decay half-lives of nuclei far from β-stable line

Experimental data of nuclear β⁺-decay half-lives are systematically analyzed and investigated. We present an exponential law between the half-life of β⁺-decay with the same forbiddenness and the nucleon number (Z,N) of parent nucleus far from the β-stable line. A formula with four parameters is proposed to describe the β⁺-decay half-lives of nuclei far from stability. Experimental β⁺-decay half-lives of the first and second forbidden transitions are well reproduced by this simple formula. The physics of the exponential law is related to the statistical properties of β⁺-decay far from β-stable line.     

Large-scale synthesis of crystalline β-SiC nanowires

Large quantities of high-purity crystalline β-SiC nanowires have been synthesized at relatively low temperature via a new simple method, the chemical-vapor-reaction approach, in a home-made graphite reaction cell. A mixture of milled Si and SiC powders and C₃H₆ were employed as the starting materials. The results show that the nanowires with diameters of about 10–35 nm are single crystalline β-SiCwithout any wrapping of amorphous material, and the nanowire axes lie along the 〈111〉 direction. Some unique properties are found in the Raman scattering from the β-SiC nanowires, which are different from previous observations of β-SiC materials. A possible growth mechanism for the β-SiC nanowires is proposed. Received: 27 August 2002 / Accepted: 28 August 2002 / Published online: 4 December 2002 RID="*" ID="*"Corresponding author. Fax: +86-29/8491-000, E-mail: zjli-sohu@sohu.com     

Supplement to anti-proton scheme of β-disintegration

The author's previous paper [2]on the possibility of extending the known scheme of -disintegration by four other anti-proton variants is rendered more exact by distinguishing between the neutrino and the anti-neutrino.     

First-principles calculations of structural and thermodynamic properties of β-PbO

We employed ab-initio calculations to investigate the structural and thermodynamic properties of Massicot or orthorhombic phase of PbO named β-PbO using the projector augmented-wave(PAW) method within the generalized gradient approximation(GGA). The temperature and pressure dependence of bulk modulus, heat capacity at constant pressure and constant volume, entropy, thermal expansion coefficient and Grüneisen parameter were discussed. Accuracy of two different models, the Debye and Debye-Grüneisen which are based on the quasi-harmonic approximation(QHA) for producing thermodynamic properties of material were compared. According to calculation results, these two models can be used to designate thermodynamic properties for β-PbO with sensible accuracy over a wide range of temperatures and pressures, and our work on the properties of this structure will be useful for more deeply understanding various properties of this structure.     

Precise measurement of the quadrupole moment of β-emitting12B

Hyperfine interactions of¹²B(I ,T _1/2=21 ms) implanted in the substitutional site of B atoms (stable) in a (single crystal like) BN (hexagonal) was studied by use of a -NMR detection. For efficient and simple measurements, the conventional -NMR has been modified as a new nuclear quadrupole resonance technique (NNQR). For the present case with the nuclear spinI=1 the detection efficiency is improved about 30 times compared with the one with the old method. The quadrupole moment of¹²B was determined precisely as ¦Q(¹²B; 1⁺)¦=13.21±0.26 mb.     

On Some Classes of New Solutions of Continuous β-FPU Chain

A continuous β-Fermi--Pasta--Ulam (FPU) chain is investigated by using the knowledge of elliptic equation and Jacobian elliptic functions. We obtain the new solutions, two-kink soliton solution, breather solution and breather lattice solution, of the continuous β-FPU chain, besides the kink-soliton solution and chaos solution.