查询词典 discontinuum

Nonstandard analysis ; nlargements of number systems ; transfer principle ; external producing principle ; comparative principle ; potential numbers ; measure ; continuum ; discontinuum ; cardinal number ; continuum hypothesis ; Hilbert's first problem Ner

非标准分析；数系的扩大；转移原则；外的生成原则；比较原则；潜在数；测度；连续统；离散统；基数；连续统假设； Hilbert第一问题；新的数学实体；不可分的连续体； Zeno的总格言； Aristotle的猜想；庄周；无厚不可积；万世不竭；测度论的基础

In cases where an equivalent continuum cannot be defined, discontinuum network simulation is a viable alternative. Howerer, these models are very demanding in terms of computer resources, which restraints their application to engineering practice.

首先，提出了一种基于混合边界元—管流的改进的三维离散裂隙网络模型，并研究了提高模型计算能力的方法，使其可以具有更好的工程应用性。

The main objective of this dissertation was to develop methodologies with capability of engineering application for simulating flow in fractured rock using discontinuum models. The study work includes three parts. In the first part, numerical methodology of three-dimensional discrete fracture network model casing on hybrid BEM-channel was presented, and the technique for improve the model's computing efficiency was also studied. Firstly in this part, computer simulation methodology based on the Baechermodel for generating network of discrete fractures was presented, which includes the follow details: probability distributions of fracture density,orientation, trace length, size, and aperture and estimation of their statistical parameters; stochastic models of fracture network; Monte-Carlo's simulation method; numerical simulation procedure and technicality.

给出了离散裂隙网络模型所依据的基本假定；发展了基于Baecher模型的离散裂隙网络计算机随机生成技术：详细地推导了单裂隙渗流和多裂隙相交网络渗流的边界单元法公式，发展了离散裂隙网络中稳态渗流的边界元数值技术，并且讨论了相关的具体数值技术细节，如角点的处理方法，单元的自动剖分等：描述了混合边界元—管流模拟方法及其数值实现；研究了裂隙网络的简化方法，并针对裂隙网络边界元法的特点提出了一种改进的分块三角分解法。

In spite of the granular nature, soil has traditionally been modeled as a continuum. This continuum mechanics cannot get the precise solution while soil\'s nonlinear, discontinuous, large deformation, and strain localization behavior are considered. The discrete element method is based on discontinuum theory, and is pioneered by Cundall.

土是由多相介质组成的离散颗粒集合体，尽管研究者早已在土的散粒状属性上达成共识，但关于土体力学性质的研究还经常沿用连续介质力学方法，这种基于连续体小变形假设的方法在求解实际土体非线性、非连续、大变形、应变局部化问题时往往无法得到精确解答。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。