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91.
92.
We study a lattice QCD mixed action with overlap valence quarks on two flavours of Wilson maximally twisted mass sea quarks. Employing three different matching conditions to relate both actions to each other, we investigate the continuum limit by using three values of the lattice spacing ranging from a≈0.05 fm to 0.08 fm. A particular emphasis is put on the effect on physical observables of the topological zero modes appearing in the valence overlap operator. We estimate the region of parameter space where the contribution from these zero modes is sufficiently small such that their effects can be safely controlled and a restoration of unitarity of the mixed action in the continuum limit is reached. 相似文献
93.
建立了ICP-AES测定超导粉中痕量镍的新方法。优化了仪器工作参数,对超导前驱粉中痕量镍测定时的基体干扰及干扰消除方法进行了系统研究,结果表明:大量存在的基体元素产生严重基体效应,导致测定重现性及准确度变差,实验采用分离富集方法以提高测定结果的准确度和精密度。实验中首先用阴离子交换树脂,除去Bi3+及部分Pb2+,Sr2+,Ca2+,Cu2+等基体元素;在碱性条件下再通过甲苯萃取镍与丁二酮肟的络合物、稀盐酸反萃取富集镍;对分离富集条件进行了优化。对模拟标准样品进行测定,分析结果与理论值一致,相对标准偏差为1.9%,方法检出限为0.19μg.g-1。该方法已用于超导前驱粉样品中痕量镍的分析,结果令人满意。 相似文献
94.
A discussion is proposed on the paper “Evaluación numérica del efecto del espesor de la placa de contacto en la acción de palanca en conexión de acero tipo T” by L.M. Bezerra, C.S. de Freitas, W.T. Matias and J.E. Carmona. The topics to be discussed are the definition of the T-stub model, the bibliographic references used in the work and the finite element analysis assumptions adopted in the modeling of the components. 相似文献
95.
The notion of a symmetric Hamiltonian cycle system (HCS) of a graph Γ has been introduced and studied by J. Akiyama, M. Kobayashi, and G. Nakamura [J Combin Des 12 (2004), 39–45] for , by R. A. Brualdi and M. W. Schroeder [J Combin Des 19 (2011), 1–15] for , and then naturally extended by V. Chitra and A. Muthusamy [Discussiones Mathematicae Graph Theory, to appear] to the multigraphs and . In each case, there must be an involutory permutation ψ of the vertices fixing all the cycles of the HCS and at most one vertex. Furthermore, for , this ψ should be precisely the permutation switching all pairs of endpoints of the edges of I. An HCS is cyclic if it is invariant under some cyclic permutation of all the vertices. The existence question for a cyclic HCS of has been completely solved by Jordon and Morris [Discrete Math (2008), 2440–2449]—and we note that their cyclic construction is also symmetric for (mod 8). It is then natural to study the existence problem of an HCS of a graph or multigraph Γ as above which is both cyclic and symmetric. In this paper, we completely solve this problem: in the case of even order, the final answer is that cyclicity and symmetry can always cohabit when a cyclic solution exists. On the other hand, imposing that a cyclic HCS of odd order is also symmetric is very restrictive; we prove in fact that an HCS of with both properties exists if and only if is a prime. 相似文献
96.
In this paper, we will estimate an upper bound for the similarity degree of the crossed product of a hyperfinite finite von Neumann algebra by weakly compact action of an infinite discrete group. We will also improve some upper bounds for similarity degrees of some finite von Neumann algebras. 相似文献
97.
利用试管、玻璃球、器、圆盘等易取材料研制了使玻璃球通过重力作用原理来转移工作物质的方法,并可用燃烧热、电阻热和光转化热作为高温热源的动力的热机实验演示,同时我们给出了相应的理论分析。 相似文献
98.
Received September 24, 1998; accepted August 9, 1999 相似文献
99.
《代数通讯》2013,41(11):5361-5376
Abstract We prove that when a countable group admits a nontrivial Floyd-type boundary, then every nonelementary and metrically proper subgroup contains a noncommutative free subgroup. This generalizes the corresponding well-known results for hyperbolic groups and groups with infinitely many ends. It also shows that no finitely generated amenable group admits a nontrivial boundary of this type. This improves on a theorem by Floyd (Floyd, W. J. (1980). Group completions and limit sets of Kleinian groups. Invent. Math. 57: 205–218) as well as giving an elementary proof of a conjecture stated in that same paper. We also show that if the Floyd boundary of a finitely generated group is nontrivial, then it is a boundary in the sense of Furstenberg and the group acts on it as a convergence group. 相似文献
100.
In this paper, using the integral method observed by Mai Jiehua recently, we show that no dendrite admits a sensitive commutative group action. 相似文献