Efficient Multiparty Quantum Secret Sharing with Greenberger-Horne-Zeilinger States

An effcient multiparty quantum secret sharing scheme is proposed with Greenberger-Horne-Zeilinger （GHZ） states following some ideas in quantum dense coding. The agents take the single-photon measurements on the photons received for eavesdropping check and exploit the four local unitary operations Ⅰ, σx, σx and iσy to code their message. This scheme has the advantage of high capacity as each GHZ state can carry two bits of information. The parties do not need to announce the measuring bases for almost all the photons, which will reduce the classical information exchanged largely. The intrinsic efficiency for qubits and the total effciency both approach the maximal values.     

Ar 原子内嵌对C60 富勒烯碰撞的影响

基于半经验势的分子动力学模型， 研究了相同能量下 C₆₀ +C₆₀ 与 Ar@C₆₀ +Ar@C₆₀ 的对心碰撞后形成的富勒烯结构的不同。 发现在相同的能量下， Ar@C60 +Ar@C60 形成的碰撞产物的结构相比 C₆₀ +C₆₀ 碰撞产物的结构有着明显的不同: 前者形成“花生”状的新富勒烯结构， 后者形成“哑铃”状的双富勒烯结构。     

直接俘获截面中的核晕效应

恒星能量下俘获截面非常难于直接测量.因此,通常借助于非直接方法或从最低能量下的实验数据外推到天体物理感兴趣能区.首先证明了用渐近归一化常数方法得到的结果近似与模型无关.因此,转移反应的渐近归一化常数方法处理提供了一可靠的途径用以确定恒星能量下的俘获截面. 鉴于此优点, 用渐近归一化常数方法计算了¹⁰Be(n,γ)¹¹Be反应的俘获截面. ¹¹Be是一个众所周知的具有两弱束缚态的晕核.作为一个典型的例子,演示了俘获到晕态的辐射俘获截面明显增大, 证明了入射中子波函数与晕的伸展尾部有较大重叠是俘获截面异常增大的原因.     

Halo Effect on Direct Neutron Capture Process

We calculate the capture cross sections of the ^10Be(n,γ) ^11Be reaction by means of the asymptotic normalization coefficient method and demonstrate the halo effects on the capture cross sections for the direct radiative neutron capture where a p-, s- or d-wave neutron is captured into an s-orbit or p-orbit in ^11Be by emitting an E1 γ-ray, respectively. The result shows that the enormous enhancement of the capture cross section is just due to the large overlap of the incident neutron wave with the extended tail of the ha/o, which is clearly illustrated by the reduced transition amplitude function.     

171Ta高自旋态能级寿命测量

在中国原子能科学研究院的HI 13串列加速器上通过157Gd(19F,5n)171Ta重离子熔合蒸发反应布居了171Ta的高自旋态,以多普勒移动衰减法的峰形分析法分析了171Tah9/2质子1/2[541]转动带的6条能级的寿命,得到了这6条能级的平均寿命值. The high spin states of~(171)Ta have been populated via heavy ion fusion evaporation reaction~(157)Gd(~(19)F, 5n)~(171)Ta at the HI-13 tandem accelerator in China Institute of Atomic Energy. The lifetimes of the high spin states in~(171)Ta have been measured by using the Doppler Shift Attenuation Method (DSAM). Six levels of its h_(9/2) proton 1/2\ band have been analyzed and their lifetimes have been deduced from the experimental data.     

核物质对称能和重离子碰撞中径向流阈能的同位旋效应

基于同位旋相关的量子分子动力学模型，采用三种不同形式的对称势，研究了¹²⁴Sn+¹²⁴Sn和¹²⁴Ba+¹²⁴Ba对心碰撞时在三种不同对称势下的径向膨胀流，发现径向膨胀流阈能与所采用的对称能形式密切相关，表现出明显同位旋效应，预示着径向膨胀流阈能的同位旋相关性可作为对称能的灵敏探针. 关键词： 径向膨胀流阈能 同位旋效应 重离子碰撞 同位旋相关的量子分子动力学模型     

Optimal reactions for synthesis of nuclides of element 108

The cross sections for the production of nuclides of element 108 via hot fusion evaporation reactions are studied using a two-parameter Smoluchowski equation. The optimal reactions for the synthesis of new nuclides of element 108 with mass numbers from 266 to 271 are suggested. The macroscopic-microscopic approach predicts a strong deformed shell closure at Z \approx 108 and N=162. The synthesis of more nuclides of element 108 is meaningful to the confirmation of the existence of this deformed shell closure.     

低能离子注入植物种子的深度分布及生物效应机理研究

采用四种物理测量方法：扫描电子显微镜和能量色散x射线分析，质子激发x荧光分析，双光子激光扫描显微技术和正电子湮没技术测定了能量为200keV V⁺ 注入干花生种 子的深度分布.测量结果表明，注入的低能离子在干种子花生内的深度远比TRIM95的理论计算值为高.对低能离子注入植物种子后的生物效应的机理进行了讨论. 关键词： 低能离子注入 植物种子 深度分布 生物效应机理     

用14MeV中子轰击铌伴生γ射线研究

利用脉冲化的T(d,n)⁴He中子源、伴随粒子方法、Ge(Li)探测器和飞行时间技术测量了14.9MeV中子和铌反应在30°—140°之间七个角度上的分立γ射线谱;由高分辨γ谱分析程序识别了79条谱线;初步确定了62条谱线所由产生的反应类型和跃迁能级,其中有40条谱线是在由中子诱发的核反应中首次发现的.定出了每条谱线在七个角度上的微分产生截面,结果表明该反应中的伴生γ发射基本上是各向同性的.     

快中子物理和实验技术研究

综述近年来在北师大低能所的国内第一台脉冲化高压倍加器上开展的快中子物理，及有关的实验和数据处理技术研究. The study on fast neutron physics and relative technique of experiment and data analysis made at a pulsed neutron generator in Beijing Normal University during recent yeras is introduced.