天然汞全套中子核反应数据的理论计算

用光学模型（ＯＰＭ），核反应多步过程的半经典理论，双微分截面理论（ＤＤＣＳ）和γ辐射的非统计过程及γ产生数据理论，计算了人射能量在０．１￣２０ＭｅＶ的中民天然汞相互作用的全套核反应数据，计算结果与评价的实验数据比较，符合较好。     

Serial nuclear transfer improves the development of interspecies reconstructed giant panda (Aluropoda melanoleuca) embryos

Interspecies somatic nuclear transfer (NT) may provide a new approach for preservation of the endangered rare species. Previous interspecies cloning studies have shown that a nucleus from a quiescent somatic cell supports early development of reconstructed embryos in the ooplasm from another species. In this study, we transferred nonquiescent somatic cells from a giant panda into the perivitelline space of the enucleated rabbit oocytes. After electrofusion (at the rate of 71.6%) and electrical activation, 4.2% of the panda-rabbit reconstructed embryos developed to blastocyst in vitro. For improving the development rate of reconstructed embryos, we used serial NT in this study, i.e. blastomeres from reconstructed morulae were transferred into the perivitelline space of the enucleated rabbit oocytes. The fusion rates in the groups of serial I, serial II and serial III were 79.5%, 84.1% and 78.0%, respectively, having no difference with that of somatic group. And the blastocyst rates in serial NT groups were 19.4%, 13.5% and 10.3%, respectively, which are significantly higher than that in somatic NT group. These results indicate that the nuclei from nonquiescent somatic cells can support early development of reconstructed embryos and serial NT can improve the development rate of interspecies reconstructed embryos. These authors contributed equally to this work.     

Telomere dynamics unique to meiotic prophase: formation and significance of the bouquet

Telomeres carry out conserved and possibly ancient functions in meiosis. During the specialized prophase of meiosis I, meiotic prophase, telomeres cluster on the nuclear envelope and move the diploid genetic material around within the nucleus so that homologous chromosomes can align two by two and efficiently recombine with precision. This recombination is in turn required for proper segregation of the homologs into viable haploid daughter cells. The meiosis-specific telomere clustering on the nuclear envelope defines the bouquet stage, so named for its resemblance to the stems from a bouquet of cut flowers. Here, a comparative analysis of the literature on meiotic telomeres from a variety of different species illustrates that the bouquet is nearly universal among life cycles with sexual reproduction. The bouquet has been well documented for over 100 years, but our understanding of how it forms and how it functions has only recently begun to increase. Early and recent observations document the timing and provide clues about the functional significance of these striking telomere movements.     

Nuclear localization of mouse fibroblast growth factor 2 requires N-terminal and C-terminal sequences

In vertebrates, different isoforms of fibroblast growth factor 2 (FGF2) exist, which differ by their N-terminal extension. They show different localization and expression levels and exert distinct biological effects. Nevertheless, genetic inactivation of all FGF2 isoforms in the mouse results in only mild phenotypes. Here, we analyzed mouse FGF2, and show that, as in the human, mouse FGF2 contains CTG-initiated high molecular-weight (HMW) isoforms, which contain a nuclear localization signal, and which mediate localization of this isoform to the nucleus. Using green fluorescent protein-FGF2 fusions, we furthermore observed, that C-terminal deletions disable nuclear localization of the short low-molecular-weight (LMW) 18-kDa isoform. This loss of specific localization is accompanied by a loss in heparin binding. We therefore suggest that, first, localization of mouse FGF2 is comparable to that in other vertebrates and, second, FGF2 contains at least two sequences important for nuclear localization, a nuclear localization sequence at the N terminus which is only contained in the HMW isoform, and another sequence at the C terminus, which is only required for localization of the LMW 18-kDa isoform. Received 1 July 2003; accepted 14 August 2003     

Kane固体量子计算机中核自旋读出

在2个量子位(qubit)的体系中,对Kane固体量子计算机模型的通过电子状态与核子自旋状态的交换进行测量的方法进行了研究。从2个量子位系统的Hamilton量出发,根据总自旋在外磁场方向的总投影分成5个不变子空间,构造它们的块对角矩阵形式。分析了它们所有的本征值和本征态随电子之间交换相互作用的大小的变化关系。结果表明:利用核自旋和电子自旋交换来测量核自旋的方法是有一定适用范围的,在2个量子位与2个电子的系统中的16个态中,只有4个可以利用这种方法来测量。     

穆斯堡尔效应的发现

介绍了穆斯堡尔的生平，回顾了穆斯堡尔发现固体中γ辐射的原子核无反冲共振吸收效应的历程，着重说明了穆斯堡尔在研究中严谨的作风，巧妙类比的思维方法以及高昂的激情在创新中发挥的重要作用．     

太阳耀斑放能机制的讨论——评《太阳高能物理》

本文对《太阳高能物理》所表述的太阳耀斑流行理论作了讨论,给出一种新的太阳耀斑放能机制——"电子—离子束缚态及其引发核过程"模型。并指出太阳耀斑中存在两个独立过程,有～12.5keV(p-e-p～12.5keV)、～25keV(p-e-A ～25keV)、～25keV(d -e-d ～25keV)线发射和(d,d)聚变。对太阳耀斑的一些主要现象作了分析,给出了太阳耀斑中X射线和高能粒子与流行理论不同的产生机制。     

Rough Sets and Nuclear Safety

It is well-known that rough set theory can be applied successfully to rough classification and knowledge discovery. Our work is concerned with finding methods for using rough sets to identify classes in datasets, finding dependencies in relations and discovering rules which are hidden in databases by means of decision tables and algorithm D. We use these methods to analyze and control aspects of nuclear energy generation.     

Wigner表示下的核流体动力学方程

基于从两体关联动力学获得的与扩展时间相关的Ｈａｒｔｒｅｅ－Ｆｏｃｋ（ＥＴＤＨＦ）方程，研究了核流体动力学模型的理论基础。同时，通过在Ｗｉｇｎｅｒ表示中定义流矢量和运动应力张量，获得了闭合的核流体动力学方程组，为更好地利用核流体动力学模型来研究核反应系统的平均动力学行为提供了必要的理论依据。     

平面反射对称操作对平均场Hamiltonian的约化

研究了原子核平均场中本征能量的求解．当不存在任何几何对称性时，能量矩阵由２ Ｎ×２ Ｎ个复数矩阵元组成（ Ｎ 为基矢的大小）；如果空间存在１ 个反射对称平面，该２ Ｎ×２ Ｎ复矩阵可约化为１ 对互为共轭Ｎ×Ｎ复矩阵或１ 个２Ｎ×２Ｎ实矩阵；如果存在２ 个互相正交对称平面，则可约化为２ 个Ｎ×Ｎ实矩阵．