| 词汇 | octahedron |
| 释义 | octahedron noun[ C ] mathematics specializeduk /ˌɒk.təˈhiː.drən/ us /ˌɑːk.təˈhiː.drən/pluraloctahedrons or octahedrauk /-drə/us a solid shape whose eight sides are triangles of equal size八面体（八个面均为等同的正三角形的棱锥体） Oleksandr Farber/iStock/Getty Images Plus/GettyImages Geometrical shapes -cornered circularly congruently conic cylindrically lozenge orbicular ovally ovoid parallelogram pentagon polyhedron polytope prism pyramid quadrilateral rectangle rectangular rhombus three-dimensional Examples of octahedronoctahedron In this context, the cube is a hexacatenane, and the truncated octahedron is a 14-catenane. Our strategy is to pack cycles into sequences of linked octahedra. We therefore need to allow some 'overflow' from one octahedron to the next. The tetrahedron, the octahedron and the cube may all be related to the diameter of the circumscribing sphere with lengths which are 'commensurable in square'. For the octahedra this is at most 5. We shall construct the packing one octahedron at a time, so that at each step we may have some incompletely packed cycles. We may also have missed at most 34 x 4 squares and triangles when we changed back some octahedra. We shall now modify the octahedra in the trail so as to include all the additional edges. We shall then pack these trails of octahedra with cycles of arbitrary lengths. Repeat this process with a different octahedron for each of the paths until we run out of paths. K (3) (2, 2, 2) is sometimes called the octahedron. Unfortunately, we now need to pack cycles into these modified octahedra, and for very short cycles we shall need to introduce several alternative modifications to the octahedra. To be specific, to which of the five platonic solids—tetrahedron, cube, octahedron, and so on—is the ideal strawberry supposed to approximate? From the Hansard archive Example from the Hansard archive. Contains Parliamentary information licensed under the Open Parliament Licence v3.0 Regular cubes and octahedrons both have 12 edges, while regular icosahedrons have 12 vertices. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The number of cubes in an octahedron formed by stacking centered squares is a centered octahedral number, the sum of two consecutive octahedral numbers. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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