Z-半连续偏序集的性质

讨论了Z-半连续偏序集上一些映射性质,Z基于不同的映得到了相关的Z-半连续序集的等价刻划．同进还定义了Z-半连续偏序集的基和Z-半代数偏序集,并讨论了Z-半连续偏序集的基的性质和Z-半代数偏序集与Z-半连续偏序集间的刻划．     

Z-局部半连续格

引入广义局部理想子集系统、Z-局部半连续格和强Z-局部连续格的概念,讨论了它们的基本性质,并给出了Z-局部半连续格的若干内部刻画.此外,探讨了Z-局部半连续映射与Z-局部半连续格上的函数空间,推广了相关文献的结论.     

半连续dcpo的局部半基的若干理论

对连续格、半连续格、半连续dcpo等的相关定义与主要性质进行比较,得到它们的联系与区别,作出一些补充,并给出半连续dcpo的局部半基的概念,从而得到一些相关性质与结论.     

Z-连续偏序集的基

引入了Z-连续偏序集的基的概念,给出了它的刻画定理.研究了Z-连续偏序集上的Z-Scott开集,Z-Lawson开集,Z-Scott拓扑及Z-Lawson拓扑的一些性质.     

拟Z-连续Domain的基

基于一般子集系统Z,引入了拟Z-连续Domain基的概念,讨论了拟Z-连续Domain基的一些映射性质,将关于拟连续偏序集的一些性质推广到了拟Z-连续Domain.     

半模的Z-同态与正合列

文章利用[1]中建立的半模monic和半模epic的方法,探讨了半模的Z-同态的某些性质;透过半模的Z-同态这个角度,得到了一类半模短正合列的一些刻画。     

Z-极小集及其对Z-连续偏序集的应用

对于一般的子集系统Z,引入了Z-极小集的概念,给出了Z-连续偏序集中保Z-极小集与保Z-并和Z间的等价刻划及其有关性质,得到了关于保Z-极小集映射的扩张定理.     

半Smooth格

该文引入半Smooth格和半Smooth代数格的概念,讨论它们的一些基本性质及与半连续格的关系,证明了完备格L是半Smooth格和半连续格当且仅当L是完全分配格.     

正则Z-算子的Z-谱及其性质

引入了正则Z-算子的Z-谱的概念,探讨了正则Z-算子的Z-谱的性质,并将泛函分析学中谱映射定理推广到Z-空间之中的Z-谱映射定理.     

自反Z-空间与一致凸Z-空间的性质

在提出的Z-空间、B-Z-空间和共轭Z-空间概念的基础上,提出了自反Z-空间和一致凸Z-空间的概念,同时探讨了自反Z-空间与一致凸Z-空间的有关性质.     

局部极大理想

分配格上的局部极大理想是素理想,而一般格上的则不然.本文证明了格上局部极大理想是素理想的几个充分必要条件,并用格中相对零化子的对偶概念描述了局部极大理想的素特征.     

T_0拓扑空间的拟连续性与交连续性

本文在定向空间的基础上通过收敛的方式定义了拟连续空间和交连续空间,推广了Domain理论中的相应结果.主要结果如下:(1)一个T_0空间是拟连续的,当且仅当它是局部强紧的,当且仅当它的开集格在集包含关系下是超连续格,当且仅当它的sober化是拟连续dcpo;(2)一个定向空间是交连续的当且仅当它的闭集格在集包含关系下是一个Frame;(3)一个T_0拓扑空间是c-空间当且仅当它既是交连续的又是拟连续的.     

上连续完备模格的半单性

对于上连续完备模格L,证明了L是局部原子格等价于1是原子的并,也等价于1是独立原子的并,并进一步给出了1可分解为有限个原子并的若干等价条件.     

Liquid-like movements in crystalline insulin

Diffuse X-ray scattering from protein crystals provides information about molecular flexibility and packing irregularities. Here we analyse diffraction patterns from insulin crystals that show two types of scattering related to disorder: very diffuse, liquid-like diffraction, and haloes around the Bragg reflections. The haloes are due to coupled displacements of neighbouring molecules in the lattice, and the very diffuse scattering results from variations in atomic positions that are only locally correlated within each molecule. The measured intensity was digitally separated into three components: the Bragg reflections and associated haloes; the water and Compton scattering; and the scattering attributed to internal protein movements. We extend methods used to analyse disorder in membrane structures to simulate the diffuse scattering from crystalline insulin in terms of (1) the Patterson (autocorrelation) function of the ideal, ordered crystal structure, (2) the root-mean-square (r.m.s.) amplitude of the atomic movements, and (3) the mean distance over which these displacements are coupled. Movements of the atoms within the molecules, with r.m.s. amplitudes of 0.4-0.45 A, appear to be coupled over a range of approximately 6 A, as in a liquid. These locally coupled movements account for most of the disorder in the crystal. Also, the protein molecules, as a whole, jiggle in the lattice with r.m.s. amplitudes of approximately 0.25 A that appear to be significantly correlated only between nearest neighbours.     

Non-destructive determination of local strain with 100-nanometre spatial resolution

Structure sizes of approximately 180 nm are now standard in microelectronics, and state-of-the-art fabrication techniques can reduce these to just a few tens of nanometres. But at these length scales, the strain induced at interfaces can locally distort the crystal lattice, which may in turn affect device performance in an unpredictable way. A means of non-destructively characterizing such strain fields with high spatial resolution and sensitivity is therefore highly desirable. One approach is to use Raman spectroscopy, but this is limited by the intrinsic approximately 0.5-microm resolution limit of visible light probes. Techniques based on electron-beam diffraction can achieve the desired nanometre-scale resolution. But either they require complex sample preparation procedures (which may alter the original strain field) or they are sensitive to distortional (but not dilational) strain within only the top few tens of nanometres of the sample surface. X-rays, on the other hand, have a much greater penetration depth, but have not hitherto achieved strain analysis with sub-micrometre resolution. Here we describe a magnifying diffraction imaging procedure for X-rays which achieves a spatial resolution of 100nm in one dimension and a sensitivity of 10(-4) for relative lattice variations. We demonstrate the suitability of this procedure for strain analysis by measuring the strain depth profiles beneath oxidized lines on silicon crystals.     

基于MRT-LBM的方腔流动局部加密算法

使用多参数弛豫模型的格子玻尔兹曼方法及D2Q9模型,对方腔流顶盖下方左右奇异角落处应用局部网格加密模拟方腔流动特性.在粗细网格界面上,建立了分布函数的转换公式,采用3次样条插值计算加密界面上插值点的参量,根据Chapman-Enskog分析,给出了应力计算公式.数值计算结果表明:对雷诺数1000的方腔流动,沿腔中心线的速度分布与经典文献结果对比效果良好,压力、涡量轮廓图的噪声明显降低,应力振荡明显减少,证实了所提局部加密方法的有效性.     

有界Heyting代数上基于理想的一致拓扑空间

为了利用拓扑学工具研究有界Heyting代数的性质和结构问题,基于由理想概念诱导的一类同余关系在有界Heyting代数(H,≤,→,0,1)上构造一致拓扑空间(H,τ)并考察其基本性质和拓扑性质,证明了(H,τ)是非连通的局部连通、局部紧、零维、第一可数的完全正则空间,(H,τ)是T1空间当且仅当(H,τ)是Hausdorff空间,获得了(H,τ)成为离散空间和紧致空间的充要条件,指出了(H,≤,→,0,1)中格运算和蕴涵运算关于一致拓扑τ都是连续的,从而构成拓扑有界Heyting代数。同时,讨论了(H,τ)的商空间性质。     

关于模格,分配格充要条件的严格推证

本文在离散数学的范围内,从格、子格、模格、分配格的定义,格的运算性质出发,充分利用两个特殊的五元格,对有关格是模格、格是分配格的充分与必要条件的五个定理作出严格的推证。     

Designer Dirac fermions and topological phases in molecular graphene

The observation of massless Dirac fermions in monolayer graphene has generated a new area of science and technology seeking to harness charge carriers that behave relativistically within solid-state materials. Both massless and massive Dirac fermions have been studied and proposed in a growing class of Dirac materials that includes bilayer graphene, surface states of topological insulators and iron-based high-temperature superconductors. Because the accessibility of this physics is predicated on the synthesis of new materials, the quest for Dirac quasi-particles has expanded to artificial systems such as lattices comprising ultracold atoms. Here we report the emergence of Dirac fermions in a fully tunable condensed-matter system-molecular graphene-assembled by atomic manipulation of carbon monoxide molecules over a conventional two-dimensional electron system at a copper surface. Using low-temperature scanning tunnelling microscopy and spectroscopy, we embed the symmetries underlying the two-dimensional Dirac equation into electron lattices, and then visualize and shape the resulting ground states. These experiments show the existence within the system of linearly dispersing, massless quasi-particles accompanied by a density of states characteristic of graphene. We then tune the quantum tunnelling between lattice sites locally to adjust the phase accrual of propagating electrons. Spatial texturing of lattice distortions produces atomically sharp p-n and p-n-p junction devices with two-dimensional control of Dirac fermion density and the power to endow Dirac particles with mass. Moreover, we apply scalar and vector potentials locally and globally to engender topologically distinct ground states and, ultimately, embedded gauge fields, wherein Dirac electrons react to 'pseudo' electric and magnetic fields present in their reference frame but absent from the laboratory frame. We demonstrate that Landau levels created by these gauge fields can be taken to the relativistic magnetic quantum limit, which has so far been inaccessible in natural graphene. Molecular graphene provides a versatile means of synthesizing exotic topological electronic phases in condensed matter using tailored nanostructures.     

基于散乱数据的层次B样条曲面重构与优化

运用B样条曲面的表示方法,构造了初始B样条曲面网格控制点逼近散乱点集,在此基础上构造包围盒进行局部搜索,用于误差检测,将查找问题转化为计算问题;并采取单元凝聚方式处理小单元,减少了误差超限的子区域个数,最后在误差超限的子区域内优化曲面.由粗糙到精细,实现了散乱数据的曲面重构与优化.该方法在误差检测和区域处理上进行修正,从而加快了搜索速度,简化了计算.算例表明,算法简单易行,逼近效果良好.