Studies of catalytic process of complete oxidation of methane by SSITKA method

This paper presents the results obtained by means of the steady state isotopic transient kinetic analysis for complete methane oxidation over the Pd(PdO)Al₂O₃ catalyst. The average surface life-time and surface concentration of methane and carbon dioxide were determined. It was found out that on the palladium catalyst there are adsorbed small amounts of methane (which does not take part in the process of oxidation) only at the temperature corresponding to the starting point of methane oxidation. Additionally, in the steady state of methane oxidation on the palladium catalyst there are present two different kinds of carbon dioxide: short- and long-resided on the catalyst surface. The average surface life-time of both kinds of carbon dioxide decreases with temperature. The surface concentration of long-resided carbon dioxide increases with temperature whereas the small maximum at about 380 °C is noticed for the surface concentration of short-resided carbon dioxide.     

固体材料中原子相干效应的研究进展

原子相干效应是光与物质相互作用的结果,它导致了一系列重要的物理现象。目前原子相干的实验研究工作主要在原子气体中开展,而与之相比固体材料中的相关实验研究具有更实际的应用前景。本文系统介绍了近年来固体材料中原子相干效应的研究进展,主要涉及电磁感应光透明、光速减慢与相干存储、存储光信息的可控制擦除、基于光存储的全光路由、双光脉冲的速度减慢和可逆存储和基于原子相干的增强四波混频等基本内容,最后还讨论了其在相关领域的应用。     

Minimal prime ideals of reduced rings

Let R be a reduced ring with Q its Martindale symmetric ring of quotients, and let B be the complete Boolean algebra of all idempotents in C, where C is the extended centroid of R. It is proved that every minimal prime ideal of R must be of the form mQ∩R for some maximal ideal m of B but the converse is in general not true. In addition, if R is centrally closed or has only finitely many minimal prime ideals, then the converse also holds. By applying the explicit expression, many properties of minimal prime ideals of reduced rings are realized more easily.     

Domination and upper domination of direct product graphs

Let $X_{\mathbb{Z}∕n\mathbb{Z}}$ denote the unitary Cayley graph of $\mathbb{Z}∕n\mathbb{Z}$. We present results on the tightness of the known inequality $\gamma \left(X_{\mathbb{Z}∕n\mathbb{Z}}\right)\le {\gamma }_t\left(X_{\mathbb{Z}∕n\mathbb{Z}}\right)\le g\left(n\right)$, where $\gamma$ and${\gamma }_t$ denote the domination number and total domination number, respectively, and $g$ is the arithmetic function known as Jacobsthal’s function. In particular, we construct integers $n$ with arbitrarily many distinct prime factors such that $\gamma \left(X_{\mathbb{Z}∕n\mathbb{Z}}\right)\le {\gamma }_t\left(X_{\mathbb{Z}∕n\mathbb{Z}}\right)\le g\left(n\right)?1$. We give lower bounds for the domination numbers of direct products of complete graphs and present a conjecture for the exact values of the upper domination numbers of direct products of balanced, complete multipartite graphs.     

Characterization of the induced matching extendable graphs with 2n vertices and 3n edges

A graph $G$ is induced matching extendable or IM-extendable if every induced matching of $G$ is contained in a perfect matching of $G$. In 1998, Yuan proved that a connected IM-extendable graph on $2n$ vertices has at least $3n?2$ edges, and that the only IM-extendable graph with $2n$ vertices and $3n?2$ edges is $T\times K_2$ , where $T$ is an arbitrary tree on $n$ vertices. In 2005, Zhou and Yuan proved that the only IM-extendable graph with $2n\ge 6$ vertices and $3n?1$ edges is $T\times K_2+e$, where $T$ is an arbitrary tree on $n$ vertices and $e$ is an edge connecting two vertices that lie in different copies of $T$ and have distance 3 between them in $T\times K_2$. In this paper, we introduced the definition of $Q$-joint graph and characterized the connected IM-extendable graphs with $2n\ge 4$ vertices and $3n$ edges.     

The induced path function, monotonicity and betweenness

The geodesic interval function I of a connected graph allows an axiomatic characterization involving axioms on the function only, without any reference to distance, as was shown by Nebeský [20]. Surprisingly, Nebeský [23] showed that, if no further restrictions are imposed, the induced path function J of a connected graph G does not allow such an axiomatic characterization. Here J(u,v) consists of the set of vertices lying on the induced paths between u and v. This function is a special instance of a transit function. In this paper we address the question what kind of restrictions could be imposed to obtain axiomatic characterizations of J. The function J satisfies betweenness if w∈J(u,v), with w≠u, implies u∉J(w,v) and x∈J(u,v) implies J(u,x)⊆J(u,v). It is monotone if x,y∈J(u,v) implies J(x,y)⊆J(u,v). In the case where we restrict ourselves to functions J that satisfy betweenness, or monotonicity, we are able to provide such axiomatic characterizations of J by transit axioms only. The graphs involved can all be characterized by forbidden subgraphs.     

Dynamic motion of whirling rods with Coriolis effect

Longitudinal vibrations coupled with transverse vibrations of whirling rods are investigated. It is known that longitudinal and transverse vibrations are governed by second and fourth order differential equations, respectively. Due to the Coriolis effect, a system of equations that governs the longitudinal and transverse displacements will be constructed by coupling these two equations together. Solutions of the equations assume small oscillations of vibration being superimposed on the steady state of the whirling rod. Exact and approximate solutions are obtained from the proposed governing equations, where the approximate solutions on displacements and natural frequencies are acquired by neglecting the Coriolis effect. A proposed numerical scheme known as complete function collocation method is implemented to solve the governing equations coupled with longitudinal and transverse displacements. The approximate results on both longitudinal and transverse natural frequencies show that natural frequencies are decreasing while the angular velocity of the rod is increasing. Exact and numerical results on both longitudinal and transverse natural frequencies show that there are no predictable trends whether natural frequencies are increasing or decreasing while the angular velocity of the rod is increasing.     

由非同分布NA序列产生的移动平均过程的完全收敛性

设{Y_n,-∞相似文献   

Quantale中的模糊滤子

在Quantale中引入模糊滤子的概念,研究了它的一系列性质,得到了若干等价刻画,讨论了Quantale中滤子和模糊滤子之间的相互确定关系,证明了Quantale态射既保模糊滤子又反射模糊滤子。给出了模糊滤子在Quantale态射下的像的具体结构。