表面缺陷对一氧化碳和甲基基团在金红石TiO2(110)表面吸附的影响

本文利用程序升温脱附技术研究了氧空位浓度对甲基基团和CO在R-TiO₂(110)表面吸附的影响. 结果表明,随着氧空位浓度的变化,吸附在桥氧位的甲基基团和吸附在五配位Ti⁴⁺位点上的CO分子的脱附温度呈现了不同的趋势,揭示了表面缺陷可能对R-TiO₂(110)不同位点上的物质吸附具有重要影响.     

Thin position for knots and 3-manifolds

We prove that for 2-bridge knots and 3-bridge knots in thin position the double branched cover inherits a manifold decomposition in thin position. We also argue that one should not expect this sort of correspondence to hold in general.     

数字温度计制作实验及研究

本文介绍了设计性实验——数字温度计制作实验的开设,并对实验中存在的问题进行了研究和解决。     

高分子溶液为连续相的悬浮液的粘弹性

综述了高分子架桥导致絮凝的悬浮液的粘弹性，及描述这种悬浮体系的逾渗方法。     

A partial enumeration algorithm for pure nonlinear integer programming

In this paper, a partial enumeration algorithm is developed for a class of pure IP problems. Then, a computational algorithm, named PE_SPEEDUP (partial enumeration speedup), has been developed to use whatever explicit linear constraints are present to speedup the search for a solution. The method is easy to understand and implement, yet very effective in dealing with many pure IP problems, including knapsack problems, reliability optimization, and spare allocation problems. The algorithm is based on monotonicity properties of the problem functions, and uses function values only; it does not require continuity or differentiability of the problem functions. This allows its use on problems whose functions cannot be expressed in closed algebraic form. The reliability and efficiency of the proposed algorithm and the PE_SPEEDUP algorithm has been demonstrated on some integer optimization problems taken from the literature.     

Changing and unchanging of the domination number of a graph

Let G be a graph and γ(G) denote the domination number of G. A dominating set D of a graph G with |D|=γ(G) is called a γ-set of G. A vertex x of a graph G is called: (i) γ-fixed if x belongs to every γ-set, (ii) γ-free if x belongs to some γ-set but not to all γ-sets, (iii) γ-bad if x belongs to no γ-set, (iv) γ^--free if x is γ-free and γ(G-x)=γ(G)-1, (v) γ⁰-free if x is γ-free and γ(G-x)=γ(G), and (vi) γ^q-fixed if x is γ-fixed and γ(G-x)=γ(G)+q. In this paper we investigate for any vertex x of a graph G whether x is γ^q-fixed, γ⁰-free, γ^--free or γ-bad when G is modified by deleting a vertex or adding or deleting an edge.     

A New Azide-Bridged Three-Dimensional Supramolecular Manganese(II) Compound: Synthesis,Crystal Structure and Magnetic Properties

A three-dimensional supramolecular compound [Mn(N₃)₂(H₂O)₃(hmt)] ₂ , where hmt stands for hexamethylenetetramine, was synthesized and characterized by IR, crystal structure and magnetic susceptibility. The compound [Mn(N₃)₂(H₂O)₃(hmt)] _n , crystallizes in the orthorhombic system, space group P_n 2₁ a, with a = 6.5201(9), b = 9.322(2), c = 22.192(3) Å, β = 90° and Z = 2. The Mn atom is coordinated in an octahedral arrangement by three nitrogen atoms from three azido ions, and three oxygen atoms from three water molecules, respectively. The azide ligand bridges Mn atoms in μ-1,3 fashion, forming a zigzag chain. Hmt connected with the zigzag chain by hydrogen bonds, to form a three-dimensional supramolecular structure. The magnetic susceptibility data show that there is an antiferromagnetic exchange interaction in the title compound. The data were modeled using an infinite chain model leading to J = -4.8 cm^?1.     

The hard-sphere fluid: New exact results with applications

A theorem for convolution integrals is proved and then applied to extend the second zero-separation theorem to the bridge functionb(r) and direct-correlation tail functionsd(r). This theorem allows us to exactly relateb(r)/r andd(r)/ratr=0 for the hard-sphere fluid to the contact value of the radial distribution functiong(r) atr= ⁺. From this we obtain immediately the exact values of b(r)/r and d(r)/r atr=0 through second order in number density . Using our results to compare the exact and Percus-Yevick (PY) bridge function, we find that they differ significantly. After obtaining the bridge function and tail function and their derivatives atr=0 andr= through, we suggest new approximations forb(0) andd(0) as well as an analytical integral-equation theory to improve the PY approximation in the pure hard-sphere fluid. The major deficiency of that approximation has been its poor assessment of the cavity function inside the hard-core region. Our theory remedies this defect in a way that yields ay(r) that is self-consistent with respct to the virial and compressibility relations and also the two zero-separation relations involvingy(r) and its spatial derivative atr=0.