Congruence triples on regular semigroups and their generalizations

In this paper, we introduce the concept of VT-congruence triples on a regular semigroup S and show how such triples can be constructed by using the equivalences on S/ℒ, S/R and the special congruences on S. Also, such congruence triples are characterized so that an associated congruence can be uniquely determined by a given congruence triple. Moreover, we also consider the VH-congruence pairs on an orthocryptogroup.     

基于不连续因子的沸水堆芯三维瞬态数值模拟

基于不连续因子校正的粗网格有限差分法是实现堆芯瞬态三维数值模拟的高效方法之一, 粗网节块的界面不连续因子与边界反照率的计算方法决定了实时数值模拟过程中的精度。在计算不连续因子的过程中, 省去了细网节块计算与粗网均匀化过程, 直接在粗网格划分情况下, 基于节块展开法和非线性迭代策略, 推导了粗网格界面不连续因子比率与边界反照率的计算公式, 并编制了相应的计算程序。沸水堆典型算例的三维瞬态模拟证实该方法可在空间域和时间域两方面, 使静态、瞬态精度均达到与先进节块法相等同的程度, 并且计算效率优于先进节块法, 为核电站全范围模拟机三维堆芯的实时仿真模型开发提供了一种切实可行的选择。     

由n次幂等矩阵确定的交换幺半群

设R是含幺结合环,n≥2为自然数.对所有的k≥1,本文给出了n次幂等矩阵集Pk^n（R）={P｜P^n=P∈Mk（R）}上的一种等价关系,证明了P^n（R）=∪k=1^∞Pk^n（R）中的等价类在给定的加法运算下构成一个交换幺半群.     

胶凝原油蠕变的时间-温度-应力等效性

黏弹性蠕变是胶凝原油重要的流变特性,要描述胶凝原油的黏弹性蠕变行为,必须同时考虑 应力、时间和温度等参数. 于是对胶凝原油进行了不同应力和不同温度下的蠕变实验,利用 时间-温度-应力等效原理分析了胶凝原油的非线性蠕变行为,得到了参考应力和参考温度下 的蠕变主曲线,并用黏弹性流变模型拟合得到了蠕变主曲线的表达式. 从而可以分别通过较 高温度和应力水平下的短期蠕变行为来预测较低温度和应力水平下的长期蠕变行为.     

The Uniqueness of AF Diagonals in Regular Limit Algebras

Necessary and sufficient conditions are obtained for the uniqueness of standard regular AF maximal abelian self-adjoint algebras in regular limit algebras up to approximate inner unitary equivalence.     

Transverse disks, symbolic dynamics, homology direction vectors, and Thurston-Nielson theory

We review some properties of transverse disks and use symbolic dynamics to determine rotation vectors from the return map to a transverse disk. We also prove connections between the symbolic dynamics and Nielson equivalence of orbits.     

Rook Poset Equivalence of Ferrers Boards

A natural construction due to K. Ding yields Schubert varieties from Ferrers boards. The poset structure of the Schubert cells in these varieties is equal to the poset of maximal rook placements on the Ferrers board under the Bruhat order. We determine when two Ferrers boards have isomorphic rook posets. Equivalently, we give an exact categorization of when two Ding Schubert varieties have identical Schubert cell structures. This also produces a complete classification of isomorphism types of lower intervals of 312-avoiding permutations in the Bruhat order.     

ED(i)形图簇的伴随多项式的因式分解及色性分析

令Dm表示三阶完全圈K3的一个顶点与路Pm-2的一个1度点重迭后得到的图；ψD^(i)(k,m），表示把Dm的第i个顶点（第1个顶点是1度点）与星图Sk 1的k度点重迭后得到的图；Erm r-1^D(i)表示把rDm中一个分支的第i个顶点与Sr的r-1度点重迭，同时把其余r-1个分支的第i个顶点分别与Sr的r-1个1度点都依次连一条边后得到的图。我们证明了对于1≤i≤m,r≥2，科簇Erm r-1^D(i) ∪(r-1)K1与Dm∪(r-2)ψD^(i)(1,m)∪ψD^(i)(r,m)两的补图是色等价的。