1) Permeable tetrahedron(s)
透空四面体(群)
2) tetrahedron frame group
四面体透水框架群
1.
The engineering protection measures of tetrahedron frame group for scour prevention and bank base eroding protection applied to practical projects and laboratory tests in recent years were systematically summarized,and the protectionmechanism and effect of tetrahedron frame group as well as their advantages and disadvantages were discussed and appraised.
系统地总结了近年来应用于实际工程和室内实验研究的四面体透水框架群防冲固脚技术的研究现状,对这种防冲固脚技术的防护机理、防护效果和防护的优缺点进行了论述和评价,并介绍了四面体透水框架群防护的工程实例,以及该防护工程技术在后续研究和工程应用的主要方向。
3) tetrahedron group
四面体群
1.
The equations of two classes of 3D polynomial maps that are equivariant with respect to the rotational symmetries of either a regular tetrahedron group or a regular octahedron group are strictly given, on the basis of which the properties of the general Julia sets created by these 3D polyno.
从理论上分析并证明了三维多项式映射满足等变的条件,精确地给出了关于正四面体群和正八面体群具有旋转不变对称性的两类三维等变映射的具体公式,在此基础上讨论并证明了三维多项式映射的广义Julia集所具有的性质。
4) Frames made of Hollow Tetrahedrons
空心四面体框架群
5) tetrahedron permeable frame
透水框架四面体
1.
Experimental study on flood control and bank protection by tetrahedron permeable frames;
透水框架四面体防洪护岸试验研究
6) tetrahedron frame
四面体透水框架
1.
Experimental study on effect of local scour at piers and protection by tetrahedron frame;
桥墩附近四面体透水框架抛投防冲效果试验研究
补充资料：四面体数
四面体数或三角锥体数是可以排成底为三角形的锥体（即四面体）的数。四面体数每层为三角形数，其公式是首n个三角形数之和，即n(n + 1)(n + 2) / 6。其首几项为：1, 4, 10, 20, 35, 56, 84, 120...（oeis:a000292）
四面体数的奇偶排列是“奇偶偶偶”。
1878年，a.j. meyl证明只有3个四面体数同时为平方数：1, 4, 19600。唯一同时是四面体数和正方锥数的数是1（beukers (1988)）。
它们可以在杨辉三角每横行从右到左或左到右的第4项找到。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。