Simple Procedure for Entanglement Transformation of Bipartite Pure States

An explicit procedure for transforming one bipartite entangled state into another via local operations and classical communication （LOCC） is presented. Our procedure is much simper than the previous ones in the sense that, it only involves two steps and the explicit expression of local general measurement used in the procedure can be obtained by solving a set of linear equations. Furthermore, this procedure is still applicable in high dimensional case.     

Optimal State Estimation of Pure Qubits on Circles

We consider the problem of state estimation of qubits chosen from circles. It is shown that any qubit encoded in pairs chosen from a fixed circle parailel to the x-y equator with different phases contains the same information. We also investigate the problem of state estimation of qubits from three circles. The optimai estimation fidelity is derived.     

矩形剖分上一类二元样条空间与薄板纯弯曲

构造性地给出了矩形剖分上分片2次一阶光滑的二元样条空间的力学背景．采用力学分析方法,通过在内网线上施加外力偶并适当取值使挠曲面成为分片形式,建立了矩形剖分上一类二元样条与薄板纯弯曲之间的对应关系,并对“光滑余因子”及“协调条件”给出了相应的力学解释．更进一步,通过引入扭矩,对上述空间中任一样条函数建立了相应的力学背景．     

蛋白质结晶学中纯直接法的新进展

纯直接法是一种abinitio方法。它只用X射线实验得到的有原子分辨水平的母体数据和单胞中原子种类及数目就能解出小蛋白质的结构位相。目前流行的双空间法SnB和SHELX-D,根据整体极小化原理设计、运用倒易空间位相修正和正空间密度修饰交替叠代的策略已能解含1001个非H肽原子的溶菌酶结构。我们采用系统论和优化法的思想与结构不变量的概率分布理论相结合,研究成功了在倒易空间直接求解位相的系统优化法及程序SYSTEM-99。用它测定了0.110nm分辨率含1914个不重于S的非H肽原子的天花粉(TCS)结构的初始模型。     

Quasipure injective torsion-free groups with indecomposable pure subgroups

In a quasipure injective torsion-free Abelian group whose pure subgroups are strongly indecomposable, any nonzero endomorphism is shown to be a monomorphism. The results of this paper together with results obtained earlier describe quasipure injective torsion-free groups. As a corollary, it is proved that any quasipure injective torsion-free group is transitive. Translated fromMatematicheskie Zametki, Vol. 68, No. 4, pp. 587–592, October, 2000.     

晶粒度对纯铝动态力学性能的影响

通过热处理方式制备了3种不同晶粒度的纯铝样品。利用分离式霍普金森压杆加载装置测量了3种纯铝在应变率102～104 s-1范围内的应力应变曲线。实验曲线表明,纯铝的屈服应力和流动应力随晶粒度的增大而减小;根据实验数据拟合了纯铝在动态下的Hall-Petch公式。同时采用一级轻气炮对3种纯铝进行了层裂实验,结果表明晶粒度对纯铝的层裂特性几乎没有影响。     

Comparative analysis of entanglement measures based on monogamy inequality

We evaluate the monogamy inequality for symmetric, non-symmetric pure states of importance in terms of squared concurrence, squared entanglement of formation, squared negativity of partial transpose and compare the corresponding tangles. We show that though concurrence and concurrence tangle are zero for two special classes of mixed entangled states, both negativity tangle and entanglement of formation(EOF) tangle turn out to be non-zero. A comparison of different tangles is carried out in each case and it is shown that while the concurrence tangle captures the genuine multiqubit entanglement in N-qubit pure states with N distinct spinors(containing GHZ and superposition of W-, obverse W states)either negativity tangle or EOF tangle is to be used as a better measure of entanglement in the W-class of states with two distinct spinors and in the special classes of mixed multiqubit states.     

高精度纯相位液晶空间光调制器的研究

研制了平行排列液晶空间光调制器（LC SLM）。论述了平行排列液晶相位调制的理论,进行了计算模拟。对液晶空间光调制器相位调制特性和振幅调制特性进行了测量,实验结果表明,在整个灰度级范围内是纯相位调制的空间光调制器,并且调制的范围可达到0．6λ。在ZYGO菲佐干涉仪上进行了精度特性的研究,得到了非常好的结果,在1cm^2的面积上,进行了畸变波前的调制,其精度峰谷值可达0．098λ,均方根值可达0．017λ。在此精度的基础上产生了π相位差的栅结构,证明了这种液晶空间光调制器可以很好的进行相位调制。     

纯弯曲下薄壁圆柱壳屈曲的非线性分析

为解决薄壁圆柱壳在纯弯曲下由于横截面的椭圆化而引起的屈曲几何非线性问题. 基本假设是改良的Brazier 简单理论,把圆柱壳的纯弯曲变形简化成一个两阶段的过程,分别求得纵向弯曲变形应变能和横截面变形应变能,然后利用最小势能原理求出作用力矩与杆端旋转角度的关系,最后分析可知:壳体长度参数越小,对应的圆柱壳壁越薄,非线性的影响越大;剪力大小参数越小,边界条件对椭圆化变形影响越小,非线性的影响越大.     

任意光滑梯度变化的功能梯度材料纯弯曲梁的弹塑性分析

假设功能梯度材料为理想弹塑性材料,其屈服强度和弹性模量均沿梁的高度方向按任意光滑函数连续变化,在小变形及平截面假定下,导出了功能梯度材料纯弯曲梁弹性极限弯矩及塑性极限弯矩的解析表达式,建立了弹塑性应力状态下截面弯矩和截面的弹、塑性应力分布之间的解析关系．研究表明,功能梯度材料梁存在多种可能的屈服模式,其最先屈服的点不一定位于截面应力最大处,而可能位于截面的其他任意位置;屈服强度及弹性模量的梯度变化对梁的弹塑性力学性能有很大影响．研究结果可为功能梯度材料纯弯曲梁的弹塑性问题研究提供一定的参考．