Nucleon properties in the covariant quark-diquark model

In the covariant quark-diquark model the effective Bethe-Salpeter (BS) equations for the nucleon and the Δ are solved including scalar and axial vector diquark correlations. Their quark substructure is effectively taken into account in both, the interaction kernel of the BS equations and the currents employed to calculate nucleon observables. Electromagnetic current conservation is maintained. The electric form factors of proton and neutron match the data. Their magnetic moments improve considerably by including axial vector diquarks and photon induced scalar-axial vector transitions. The isoscalar magnetic moment can be reproduced, the isovector contribution is about 15% too small. The ratio μG _E/G _M and the axial and strong couplings g _A, g _NN, provide an upper bound on the relative importance of axial vector diquarks confirming that scalar diquarks nevertheless describe the dominant 2-quark correlations inside nucleons. Received: 3 July 2000 / Accepted: 15 August 2000     

阶化 Cartan 型李超代数的结合型

本文确定了具有非退化结合型的Ｃａｒｔａｎ型李超代数。     

sPS/iPP共混物晶型研究

间规聚苯乙烯 (ｓＰＳ)由于熔点高达 2 70℃ ,并具有优良的耐热、耐水、耐溶剂及良好的电绝缘性[1] ,已成为一种新型高性能的半结晶热塑性工程塑料 .但是ｓＰＳ分子链刚性比较大 ,比较脆 ,结晶速度快 ,加工流动性差 ,特别是在熔体加工过程中很容易开裂 ,因此限制了其广泛应用 .为了提高它的韧性和改善其加工性能 ,通常采用物理共混和化学共聚的方法 .如ｓＰＳ ａＰＳ共混物 ,苯乙烯和丙烯的嵌段共聚物等 .间规聚苯乙烯与聚丙烯之间不相容 ,使用物理共混方法得到的共混物的性能得不到明显改善 .最近我们试图采用一种新型3 茚基乙酰丙酮为给电…     

双核浆叶式钨配合物电子结构和电子光谱的理论研究

用密度函数理论中的B3LYP方法,对甲脒做配体的过渡金属双核浆叶式配合物W2（form)4((form)^-=[(p-tol)NCHN([p-tol)^-]^-)进行了分子轨道计算,结果表明,W－W键具σ^2π^4δ^2四重键的性质,W－W间的成键和反键分子轨道顺序为σ＜π＜δ＜σ^*＜π^*＜δ^*。用单激发组态相互作用（CIS）方法计算了W2(form)4的电子吸收光谱,得到这种配合物的最低能吸收光谱为λ＝496nm,这是δ（dxy）→σ^*(spz)跃迁产生的,属于金属内部的电荷迁移。     

A new equilibrium form of zircon crystal

The surface tensions of the {100}, {110}, {101} and {211} faces are calculated by using Machenzie's method. A new equilibrium form of zircon crystal is then derived on the basis of Wulf's Law. This theoretic form consists of {100} prismatic faces and {211} pyramidal faces, which is different from that of the prediction by the periodic bond chain theory. The discovery of the equilibrium form of zircon crystal provides a clue for understanding of the morphology of zircon crystals formed in deep magma chamber, indicating that zircon morphology is an indicator of crystallization conditions.     

平面上含鞍结点与中心型鞍点的余维3环的三参数开折

本文应用有限光滑正规形理论研究了含有一个重数为2的鞍结点与一个中心型双曲鞍点（双曲比率为1）的余维3的平面环（Polycycle）的一般三参数开折与环性,证明了这类环至多分支出三条极限环,并且在一般性条件下环性为3,给出了分支图和相应的相图．作为应用,证明了文［4］提出的图（I192）环性为1的猜想．     

Recall in extensive form games

This paper considers characterizations of perfect recall in extensive form games. It is shown that perfect recall can be expressed in terms of choices without any reference to infomation sets. When information sets are taken into account, it is decomposable into an ordering of information sets and that players do not forget what they knew nor what they did. Thus, if information sets are partially ordered, then perfect recall is implied by the player's inability to refine her information from the memory. Received: August 1997/final version: September 1998     

炮弹头螺受力分析及联接方式改进

运用受力分析的方法,对弹丸头螺在全弹道过程中的受旋力进行分析,提出头螺与弹炸联接方式的改进意见,并通过试验予以验证,为某型榴弹的安全生产解决了一个实际问题．