Gleeble-3800热模拟试验机故障的检测及处理

介绍了Gleeble-3800热模拟试验机运行一年来陆续出现的一些故障及对故障的排查过程和解决方法.     

新一代航空发动机燃烧室

针对新一代高油气比(0.051及以上)航空发动机燃烧室,本文提出头部采用化学恰当比直接混合燃烧设计方案.对于新一代高压比(70及以上)低排放民用航空发动机燃烧室,由于其自着火延迟时间极短,因此采用贫油直接混合燃烧,而不能采用预混合预蒸发燃烧.本文提出了一种贫油直接混合低排放燃烧室方案,其燃油空气模由简单的压力雾化喷嘴和...     

Ding分次模和强Ding分次模

研究了分次环R上的Ding分次投射(内射)R-模以及强Ding分次投射(内射)R-模,证明了任意分次环上的Ding分次投射(内射)模类是投射(内射)可解的.研究了强Ding分次投射(内射)R-模与Ding分次投射(内射)R-模之间的关系,以及强Ding分次投射(内射)R-模与非分次的强Ding投射(内射)R-模之间的关系.证明了对有限群分次环R,若M是强Ding投射(内射)R-模,则F(M)是强Ding分次投射(内射)的;若N是强Ding分次投射(内射)R-模,则U(N)是强Ding投射(内射)的.     

NUMERICAL STUDY OF STEADY LAMINAR FLOW THROUGH TUBES WITH MULTIPLE CONSTRICTIONS USING CURVILINEAR CO-ORDINATES

The flow field through tubes with multiple axisymmetric constrictions in tubes was studied numerically. Two practical problem cases were considered and the numerical scheme was developed for both. In the first case there are one, two, three and four constrictions in the tube. The effects of the number of constrictions on wall shear stress, pressure drop, streamline, vorticity and velocity distributions as the flow passes through the tube were studied and the development of the periodicity characteristics was investigated. In the second case there were multiple constrictions in the tube equidistant from each other. For this case the governing equations were reformulated for a module at a sufficient distance downstream from the inlet where the entrance region effects could be ignored and flow field is assumed to repeat itself. The flow field solutions were obtained in this region. The governing equations were formulated in curvilinear co-ordinates and a finite volume discretization procedure was used to solve the problem. The computations were carried out over a range of Reynolds numbers between 50 to 250 for constrictions with 75 percent area reduction. The method is validated by comparing some of the solutions with experimental results.     

Kan Extensions of Internal Functors. Algebraic Approach

We investigate the question of the Kan extension in the case when all categories and functors are internal in the category of groups. Under certain assumptions we establish the necessary and sufficient conditions for the existence of internal Kan extensions. Questions related to this problem are also discussed.     

Derived Functors of Hom Relative to Flat Covers

We study the derived functors of Hom that are computed by using flat resolutions of Hom. These are denoted ⁿ. We compare these with the usual Extⁿ's and show that ¹⊂ Ext¹and indicate (using MacLane's terminology) why the class of associated short exact sequences is a proper class. When the ring is a Dedekind domain we classify the N such that ⁿ(–, N) = 0 and show that unlike the situation for other classically defined right derived functors of Hom, Hom is not balanced relative to the two classes of modules that make ¹ vanish.     

1310nm LD组件高低温循环寿命研究

研究了半导体激光二极管(LD)组件的使用寿命。模拟了在不同的环境条件下,对1310 nm LD组件进行了高低温循环寿命实验,建立了循环寿命的数学模型。结果表明:循环寿命与循环的温差、循环的速度成指数关系,通过测试LD组件在高温差、高循环速度条件下的循环寿命,外推器件正常工作条件下的循环寿命。得到了LD组件可靠性数据,为工艺设计人员提出量化数据。     

关于Kellogg定理的若干推广

本文以连续模,光滑模为工具,讨论由单位圆至光滑的若当曲线Ｌ所范单连通区的保角映射问题,对于Ｋｅｌｌｏｇｇ定理作了较大幅度的推广,得出了新的结果。     

Structure indices for multidimensional systems

The structure indices of a one-dimensional system are an importantset of invariants. In this paper we examine a generalizationof this concept to multidimensional linear systems, which correspondsto the algebraic concept of a Hilbert series. We use the standardtheory of the Hilbert series to explain some of the previousID system-theoretic results. We discuss the computation of nDstructure indices from an initial condition set, and the invariantswhich can be derived from these indices.     

对偶双代数

在文献[1]中,作者引入了扭曲积（twistingproduct）概念,并指出量子偶（Drinfel’ddouble）D（H）为张量积代数的扭曲积．本文把扭曲积加以推广为扭曲模,并给出它的基本结构定理．同时,我们引进对偶Hopf模,它是[2]中对偶Hopf模的发展．