Quasiparticle nature of rotational bands in Pt-187

The high-spin states in Pt-187 have been studied experimentally by means of in-beam gamma-ray spectroscopy techniques via the Yb-173(O-18, 4n) fusion-evaporation reaction. The high-spin level scheme of Pt-187 has been established, including three rotational bands. Based on the systematics of level structure in neighboring nuclei and by comparing the experimental and theoretical B(M1)/B(E2) ratios, configurations of 11/2+ [615], 7/2(-)[5031 and 1/2(-)[521] have been proposed for the three rotational bands, respectively. Band properties of band crossing frequency, alignment gain and signature splitting have been discussed.

High-spin states and collective band structures in the odd-odd Pm-140 nucleus

The high-spin states of Pm-140 have been investigated through the reaction Te-126(F-19, 5n) at a beam energy of 90 MeV. A previous level scheme based on the 8(-) isomer has been updated with spin up to 23 (h) over bar. A total of 22 new levels and 41 new transitions were identified. Six collective bands were observed. Five of them were expanded or re-constructed, and one of them was newly identified. The systematic signature splitting and inversion of the yrast pi h(11/2)circle times vh(11/2) band in Pr and Pm odd-odd isotopes has been discussed. Based on the systematic comparison, two Delta I = 2 bands were proposed as double-decoupled bands; other two bands with strong Delta I = 1 M1 transitions inside the bands were suggested as oblate bands with gamma similar to -60 degrees; another band with large signature splitting has been proposed with oblate-triaxial deformation with gamma similar to -90 degrees. The characteristics for these bands have been discussed.

165Er的高自旋态研究

利用能量为42MeV和45MeV的9Be束流轰击160Gd自支撑靶，通过160Gd(9Be,4n)165Er熔合蒸发反应研究了165Er核的高自旋态结构。基于实验测量结果，扩展了基于ν5/2−[523]和ν5/2+[642]准粒子组态的转动带，观测到了连接这两条具有不同宇称的转动带的强电偶极跃迁。利用跃迁分支比，提取了带间电偶极跃迁的约化跃迁概率，并讨论了强电偶极跃迁与八极关联之间的关系。提取了ν5/2−[523]和ν5/2+[642]转动带的顺排角动量和能级能量旋称劈裂值，并进行了简单讨论。 High-spin states of 165Er have been studied using the 160Gd(9Be, 4n)reaction at beam energies of 42 and 45 MeV. The previously known bands based on the ν5/2−[523] and ν5/2+[642] configurations have been extended to high-spin states, and electric-dipole transitions linking these two opposite parity bands were observed. Relatively large B(E1) values have been extracted experimentally from the branching ratios, and were attributed to octupole softness. Alignment and signature splitting in energies in the ν5/2−[523] and ν5/2+[642] bands have been extracted and discussed briefly. 熔合蒸发反应;高自旋态;电偶极跃迁;八极关联

165Er的高自旋态研究

利用能量为42MeV和45MeV的9Be束流轰击160Gd自支撑靶，通过160Gd(9Be,4n)165Er熔合蒸发反应研究了165Er核的高自旋态结构。基于实验测量结果，扩展了基于ν5/2−[523]和ν5/2+[642]准粒子组态的转动带，观测到了连接这两条具有不同宇称的转动带的强电偶极跃迁。利用跃迁分支比，提取了带间电偶极跃迁的约化跃迁概率，并讨论了强电偶极跃迁与八极关联之间的关系。提取了ν5/2−[523]和ν5/2+[642]转动带的顺排角动量和能级能量旋称劈裂值，并进行了简单讨论。 High-spin states of 165Er have been studied using the 160Gd(9Be, 4n)reaction at beam energies of 42 and 45 MeV. The previously known bands based on the ν5/2−[523] and ν5/2+[642] configurations have been extended to high-spin states, and electric-dipole transitions linking these two opposite parity bands were observed. Relatively large B(E1) values have been extracted experimentally from the branching ratios, and were attributed to octupole softness. Alignment and signature splitting in energies in the ν5/2−[523] and ν5/2+[642] bands have been extracted and discussed briefly. 熔合蒸发反应;高自旋态;电偶极跃迁;八极关联

Strong designated verifier signature in a multi-user setting

The security of strong designated verifier (SDV) signature schemes has thus far been analyzed only in a two-user setting. We observe that security in a two-user setting does not necessarily imply the same in a multi-user setting for SDV signatures. Moreover, we show that existing security notions do not adequately model the security of SDV signatures even in a two-user setting. We then propose revised notions of security in a multi-user setting and show that no existing scheme satisfies these notions. A new SDV signature scheme is then presented and proven secure under the revised notions in the standard model. For the purpose of constructing the SDV signature scheme, we propose a one-pass key establishment protocol in the standard model, which is of independent interest in itself.

A novel nonrepudiable threshold multi-proxy multi-signature scheme with shared verification

Tzeng et al. proposed a new threshold multi-proxy multi-signature scheme with threshold verification. In their scheme, a subset of original signers authenticates a designated proxy group to sign on behalf of the original group. A message m has to be signed by a subset of proxy signers who can represent the proxy group. Then, the proxy signature is sent to the verifier group. A subset of verifiers in the verifier group can also represent the group to authenticate the proxy signature. Subsequently, there are two improved schemes to eliminate the security leak of Tzeng et al.’s scheme. In this paper, we have pointed out the security leakage of the three schemes and further proposed a novel threshold multi-proxy multi-signature scheme with threshold verification.