A compact alternate direct implicit difference method for solving parabolic equation of multi-dimension

A compact alternate direct implicit difference method for multi-dimensional parabolic equation is studied in this paper. Firstly, a compact difference scheme is derived by using the operator method and the expression of the truncation error is given. Secondly     

Classification of Quasifinite Modules with Nonzero Central Charges for EALAs of Type A with Coordinates in Quantum Torus

The author first constructs a Lie algebra ∑ ：=∑（q, Wd） from rank 3 quantum torus, which is isomorphic to the core of EALAs of type Ad-1 with coordinates in quantum torus Cqd, and then gives the necessary and sufficient conditions for the highest weight modules to be quasifinite nonzero central charges are Finally the irreducible Z-graded quasifinite ∑-modules with classified.     

光伏组件测试仪的光辐照度不均匀性检验系统的研究和设计

通过对传统光伏组件测试设备检验方式的分析,提出了一种一次闪光就能够完成对测试仪工作平面辐照不均匀性测试的方法,在设计中充分使用了国际知名公司新生产的元器件,设计了信号调理电路和数据采集电路,电路设计简单,成本低廉易于实现,采集精度符合设计要求。并编写了上位机的测试程序,对辐照不均匀性测试进行了验证,结果表明测试工艺简单,数据可靠,生产效率高。     

基于ANSYS ACP的复合材料螺旋桨流固耦合计算方法

针对复合材料螺旋桨的流固耦合水弹性行为,为形成双向耦合的集成平台,对复合材料螺旋桨进行了流固耦合计算方法的研究。在ANSYS Workbench平台中,采用ACP模块对复合材料螺旋桨的建模进行了分析,介绍了复合材料螺旋桨的建模流程、流体计算模型和固体计算模型。通过静态加载试验对复合材料螺旋桨建模方法的可靠性进行了验证,计算值与试验值的偏差在5.1%以内,且反映出材料的各向异性。通过空泡水洞模型试验对复合材料螺旋桨流固耦合敞水性能计算方法的精确度进行了验证,在转速为12.7r/s和25r/s两个工况下计算的推力和扭矩与试验值吻合较好。验证了基于ANSYS ACP的复合材料螺旋桨稳态流固耦合计算方法合理可行,为复合材料螺旋桨的流固耦合振动特性分析提供了参考。     

关于一族模的任意重张量积的实性

引进一族模的任意重张量积的概念.通过建立一个充分必要条件,模的任意重张量积的半实性被得到刻画。此外,本文给出了一族模的张量积具有序的一些充分必要条件。     

Auslander–Reiten components with bounded short cycles

We study Auslander–Reiten components of an artin algebra with bounded short cycles, namely, there exists a bound for the depths of maps appearing on short cycles of non-zero non-invertible maps between modules in the given component. First, we give a number of combinatorial characterizations of almost acyclic Auslander–Reiten components. Then, we shall show that an Auslander–Reiten component with bounded short cycles is obtained, roughly speaking, by gluing the connecting components of finitely many tilted quotient algebras. In particular, the number of such components is finite and each of them is almost acyclic with only finitely many DTr-orbits. As an application, we show that an artin algebra is representation-finite if and only if its module category has bounded short cycles. This includes a well known result of Ringel’s, saying that a representation-directed algebra is representation-finite.     

Wakamatsu-silting complexes

We introduce Wakamatsu-silting complexes (resp., Wakamatsu-tilting complexes) as a common generalization of both silting complexes (resp., tilting complexes) and Wakamatsu-tilting modules. Characterizations of Wakamatsu-silting complexes are given. In particular, we show that a complex T is Wakamatsu-silting if and only if its dual DT is Wakamatsu-silting. It is conjectured that compact Wakamatsu-silting complexes are just silting complexes. We prove that the conjecture lies under the finitistic dimension conjecture.     

Coherent rings and absolutely pure covers

In this paper, we prove that a ring R is left coherent if and only if the class 𝒜bs of absolutely pure left R-modules is a covering class.     

Virtually semisimple modules and a generalization of the Wedderburn-Artin theorem

A widely used result of Wedderburn and Artin states that “every left ideal of a ring R is a direct summand of R if and only if R has a unique decomposition as a finite direct product of matrix rings over division rings.” Motivated by this, we call a module M virtually semisimple if every submodule of M is isomorphic to a direct summand of M and M is called completely virtually semisimple if every submodule of M is virtually semisimple. We show that the left R-module R is completely virtually semisimple if and only if R has a unique decomposition as a finite direct product of matrix rings over principal left ideal domains. This shows that R is completely virtually semisimple on both sides if and only if every finitely generated (left and right) R-module is a direct sum of a singular module and a projective virtually semisimple module. The Wedderburn-Artin theorem follows as a corollary from our result.