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111.
本文提出了一种用线阵CCD非接触实时测量塑料导线直径的仪器,它有如下特点:(1)采用了对被测目标所发出的烟雾不敏感的光学系统,提高了测量精度;(2)采用工作于脉冲方式的大功率近红外LED做照明光源,其寿命比采用白炽灯作为光源大为增长,同时缩小了体积并有利于抑制可见光的干扰;(3)对电信号采用了两级滤波、直流恢复、自适应阈值二值化等处理技术;(4)采用定标的方法来消除目标位置移动的影响,提高了测量精度,降低了加工装配精度要求。现场使用证明,它能长期可靠地工作,总的测量误差小于±0.02mm。 相似文献
112.
Azriel Rosenfeld 《Fuzzy Sets and Systems》1984,13(3):241-246
In pattern recognition one often wants to measure geometric properties of imprecisely defined subsets of an image. This paper proposes definitions of intrinsic and extrinsic diameter for fuzzy subsets which reduce to the ordinary definitions when the subsets are crisp. We also define height and width for a fuzzy subset and show how they relate to the area (i.e., integral of membership). For convex fuzzy subsets the intrinsic diameter cannot exceed the extrinsic diameter, but it can be smaller. Finally, for piecewise constant convex fuzzy subsets the intrinsic diameter cannot exceed half the fuzzy perimeter, but this need not be true in the nonconvex case. 相似文献
113.
Résumé Une étude systématique des volumes libres extrapolés à fluidité nulle a été menée sur une vingtaine de liquides. Une nouvelle équation est proposée pour ce volume libre limite, noté «V.L.L.» et nous la comparons à celle déduite des calculs de l'Hydrodynamique classique; elle permet de déterminer les valeurs de diamètres moléculaires; ces dernières sont en bon accord avec celles obtenues de la viscosité des gaz, de la diffusion Raman ou Rayleigh. En outre, et aux erreurs expérimentales près, les valeurs des diamètres moléculaires sont données pour 10 dérivés du benzène, valeurs qui ne se trouvent pas, à notre connaissance, dans la littérature, exception faite du benzène pur.
Summary A systematic study of free volumes extrapolated at zero fluidity is executed for 20 liquids. A new equation for this Limit Free Volume (V.L.L.) is proposed and compared with the theoretically calculated free volume; values of molecular diameters are determined and found to be in good agreement with values obtained from gas viscosity, Raman and Rayleigh scattering, respectively. Moreover, within experimental error, values of molecular diameters are found for 10 benzene derivatives which are not, at our knowledge, available in the literature, except for pure benzene.
Avec 1 figure et 3 tableaux 相似文献
114.
ZOUYi* HE Deping* & JIANG Jiaqiao Department of Material Science Engineering Southeast University Nanjing China 《中国科学B辑(英文版)》2004,47(5):407-413
The Ultra Light Metal Structure with variouskinds of pores (open, close) realizes the lightness andmultifunction of structural material. The functionsinclude lightness (ρ < 1), high specific strength, highenergy absorption, sound insulation, heat insulationand electromagnetism shield. It is one of the hotspotsin material research nowadays[1— . The requirements 6]of high speed movement and high technology make Alalloy foam, which has higher specific st… 相似文献
115.
The vector partition problem concerns the partitioning of a set A of n vectors in d-space into p parts so as to maximize an objective function c which is convex on the sum of vectors in each part. Here all parameters d, p, n are considered variables. In this paper, we study the adjacency of vertices in the associated partition polytopes. Using our adjacency characterization for these polytopes, we are able to develop an adaptive algorithm for the vector partition problem that runs in time O(q(L)v) and in space O(L), where q is a polynomial function, L is the input size and v is the number of vertices of the associated partition polytope. It is based on an output-sensitive algorithm for enumerating all vertices of the partition polytope. Our adjacency characterization also implies a polynomial upper bound on the combinatorial diameter of partition polytopes. We also establish a partition polytope analogue of the lower bound theorem, indicating that the output-sensitive enumeration algorithm can be far superior to previously known algorithms that run in time polynomial in the size of the worst-case output. 相似文献
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119.
In this paper we continue the study of paired-domination in graphs introduced by Haynes and Slater (Networks 32 (1998), 199–206). A paired-dominating set of a graph G with no isolated vertex is a dominating set of vertices whose induced subgraph has a perfect matching. The paired-domination
number of G, denoted by γ
pr(G), is the minimum cardinality of a paired-dominating set of G. The graph G is paired-domination vertex critical if for every vertex v of G that is not adjacent to a vertex of degree one, γ
pr(G − v) < γ
pr(G). We characterize the connected graphs with minimum degree one that are paired-domination vertex critical and we obtain sharp
bounds on their maximum diameter. We provide an example which shows that the maximum diameter of a paired-domination vertex
critical graph is at least 3/2 (γ
pr(G) − 2). For γ
pr(G) ⩽ 8, we show that this lower bound is precisely the maximum diameter of a paired-domination vertex critical graph.
The first author was supported in part by the South African National Research Foundation and the University of KwaZulu-Natal,
the second author was supported by the Natural Sciences and Engineering Research Council of Canada. 相似文献
120.
Xuegong Tan 《Discrete Mathematics》2008,308(20):4786-4790
The k-dimensional folded Petersen graph, FPk, is an iterative Cartesian product on the simple Petersen graph. As an essential component of folded Petersen cube, folded Petersen graph has many important properties. In this paper, we prove that the 3k-wide diameter and 3k-fault diameter of k-dimensional folded Petersen graph is either 2k+1 or 2k+2. Furthermore, we show that FPk is interval monotone. 相似文献