有限模型

Central South University, Changsha 410075, China）Abstract: Based on 2D steady and incompressible Navier-Stokes equation and k-ε turbulent model,the lateral aerodynamic performances of four types of car, i.e. passenger car, gondola car, boxcar and tank car were analyzed and compared by finite volume method, when these cars were in the cross winds of the same velocity and on the railway with the embankment of the same height.

摘 要：根据二维定常不可压缩Navier-Stokes方程和k-ε双方程紊流模型，采用有限体积法对客车、敞车、棚车和罐车4种不同外形铁路车辆在路堤高度、横风风速相同条件下的横向气动性能进行分析与比较。

Using Chebyshev approximation method,we designed a FIRlowpass differentiator suit for airborne gravimetry application,and simulate a mathematical model to test the reliability of this filter.

根据契比雪夫逼近理论，设计了适用于航空重力测量应用的有限冲激响应低通差分器，利用模拟模型对滤波器的性能进行了验证。

In the first part, first, the operational principle of Varivec Propeller is explained. Secondly, the mathematical model for predicting longitudinal and transverse movement hydrodynamic characteristics of Varivec Propeller under steady or unsteady condition are present, based on the general propeller lifting-surface theory, potential flow theory and Green theorem. Thirdly, theoretical calculation methods for predicting hydrodynamic characteristics when the influence of paraboloidal boss on the performance of Varivec Propeller is or isn't considered are present, based on The finite basic solution method, the unsteady vortex lattice method and Hess-Smith method Different rake angle is adopted according to different desire in practical application.

在理论计算部分，本文首先给出了全方向推进器的工作原理，然后基于常规螺旋桨升力面理论、势流理论和格林定理建立了定常和非定常状态下全方向推进器纵向、横向运动的水动力性能计算的数学模型，并利用有限基本解法、非定常涡格法和Hess-smith方法分别对考虑和不考虑桨毂影响时的全方向推进器纵向、横向运动水动力性能进行了数值预报。

Chapter 3 is to investigate the control design of switched dissi-pative Hamiltonian system with finite number of subsystems.

第三章研究了有限个子模型的切换耗散Hamilton系统的控制设计问题。

Based on the coupled discrete tent spatiotemporal chaotic maps, a cryptographic Hashing function is constructed to generate 128-bit Hash value from a message with arbitrary length.

与帐篷映射相比，该方案所采用的离散耦合帐篷时空混沌模型避免了有限精度实现产生的短周期行为，产生的时间序列近似服从均匀分布，具有更为理想的扩散与混乱特性。

Three China Holstein male cattle were fed with three mixed diets of forage and concentrate.

而国内在此方面的报道很有限，所以急需建立各品种反刍动物的估测模型，扩大该方法的应用范围。

Also, we give the definition of the population's states and establish the finite homogeneous Markov Chain Model of the population's states.

准确刻画了扩展相似推理学习算法中种群的状态空间，建立了扩展相似推理学习算法种群状态的齐次有限Markov链模型。

Therefore, this article based on consumer switching costs and the limited liability effect of debt, builded a duopoly competition model of horizontal differentiation, using a combination of game theory and computer simulation to be an analysis methods, inspection the firm's Financial decisions in the capital market and the competitive strategy in product market when the customer switching costs existed.

因此，本文基于对消费者行为中的顾客转换成本考虑，从债务的有限责任效应出发，构建一个双寡头的横向差异化竞争模型，采用博弈论与计算机模拟相结合的分析方法，考察存在顾客转换成本时，企业在资本市场上作出的融资决策以及在产品市场上作出的竞争策略。

According to the features and analysis of a howitzer ,some components are considered as rigid bodies and some as springs.

根据某火炮的结构特点和分析要求，把一些工程元件简化成刚体，另一些工程元件简化成弹簧，用有限多个质量、转动惯量、弹簧和阻尼形成一个离散的参数系统，从而得到火炮系统的简化模型。

The solution to the one dimensional hyperbolic runoff equations and sediment equation are obtained respectively by using the characteristics method and finite difference method.

利用水力学原理建立了坡面降雨径流和土壤侵蚀模型，分别采用特征线法和有限差分法对径流量和土壤侵蚀量进行了求解，并针对具体降雨事件进行了模拟计算，计算结果与试验小区实测值基本一致。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。