M. L. Li

Search for the chiral doublet bands in 122Cs

High spin states in the odd–odd nucleus 122Cs have been studied by in-beam γ-ray spectroscopy with a 107Ag(19F,1p3n) fusion-evaporation reaction at a beam energy of 85 MeV. A previously known πh11/2 ⊗ νh11/2 yrast band was confirmed and its spin I was re-examined. A ΔI = 2 band was identified, which together with another known ΔI = 2 band forms a side band of the πh11/2 ⊗ νh11/2 yrast band. The two observed πh11/2 ⊗ νh11/2 bands are proposed as a pair of chiral doublet bands in 122Cs based on a systematic comparison with those in the neighbouring odd–odd Cs isotopes, as well as the relativistic mean field and the triaxial particle-rotor-model calculations.

Identification of Collective Oblate Bands in 138Ce

High spin states in 138Ce have been investigated following heavy-ion induced reactions carried out at the China Institute of Atomic Energy, Beijing. Two collective rotational bands were established for the first time. These two bands show oblate deformation with γ = -60° and probably originate from the four quasiparticle configurations πg7/2 ⊗ πh11/2 ⊗ νh11/2 ⊗ νd3/2 and πg7/2 ⊗ πh11/2 ⊗ [νh11/2]2, respectively. These oblate bands exhibit strong M 1 transitions, no signature splitting and different moments of inertia from those of prolate bands.

Multi-level error detection and concealment algorithm to improve speech quality in GSM full rate speech codecs

Digital mobile telecommunication systems, such as the global system for mobile (GSM) system, want to further improve speech communication quality without changing the channel encoders and decoders. Speech quality is most affected by residual bit errors in received speech frames. Conventional methods use binary decision strategies for error detection and concealment in frames. This paper presents a multi-level error detection and concealment algorithm for GSM full rate speech codec systems. The algorithm uses multi-source knowledge to detect and conceal speech frame errors at the frame, parameter, and even bit levels. Tests show that most corrupted frames can be appropriately concealed by this algorithm, resulting in MOS gains of more than 50% for real-world data tests.

High Spin States in 136,137La and 148Ce Nuclei

High spin states in 136,137La and 148Ce nuclei have been investigated. The new level schemes for these nuclei have been established. In 136La, observed band crossing as well as the signature splitting and inversion in πh11/2⊗νh11/2 band has been discussed. Other two bands were proposed as oblate deformation with γ ∼ −60°. In 137La, several new bands have been established. The band crossing and oblate deformation have been discussed. In 148Ce, the double octupole deformation bands with s = +1 and s = −1 have been proposed.

High spin octupole correlations in the N = 85, 139Xe and 141Ba isotones

High spin states in and have been investigated using - and - coincidence studies of spontaneous fission of . Alternating parity bands built on a 7/2-level are assigned up to spin I = (37/2) and I = (29/2) in and , respectively. Another possible octupole band based on multiplet with spin up to (29/2) also is observed in both nuclei. Cascades of enhanced E1 transitions and ratios indicate strong octupole correlations. Systematics of the , and multiplets and bands in N = 85 isotones are presented.