查询词典 mathematical expectation

Aiming at the problem that the seeds picked up by the suction plate of the seed metering device cannot accurately fall into the seed pit opener as well as into the seed pit, an innovated seed metering device on which the seed dropping angle can be adjusted within a certain range and a new testing stand have been developed in accordance with the mathematical calculation model that had 'in accordance with the mathematical calculation model that had been established previously.

本论文根据2BQM-2型气吸式精量铺膜播种机的结构和工作原理，针对该机在实际播种中，吸种盘吸出的种子不能满足准确地落入在膜上滚动开穴的鸭嘴内，并及时地排入到鸭嘴所成的穴孔内的设计要求，进行了一定的试验研究，利用已建立的计算数学模型，设计新的试验台，改进排种器，使排种器的落种角度可以在一定的范围内调整。

According to legend, the way Pythagoras discovered that musical notes could be translated into mathematical equations was when one day he passed blacksmiths at work, and thought that the sounds emanating from their anvils being hit were beautiful and harmonious and decided that whatever scientific law caused this to happen must be mathematical and could be applied to music.

传说毕达哥拉斯是这样发现音符可以转化成数学方程的：有一天他经过铁匠铺的时候就想，从击打铁砧飞出来的声音很好听也很和谐，他就确定：产生这种现象的科学规律必定是数学的而且可以用到音乐中来。

The paper discussed the main factors that influence the design of the boring cutter hilt, constructed the optimizing mathematical model of the boring cutter hilt based on the basis of ANSYS, and made solution for the mathematical model with the help of the optimizing tools of ANSYS. The result shows that the method is a scientific and practical method for the design of boring cutter hilts, and can have great influences on improving the design precision.

分析了影响镗刀杆设计的主要因素，建立了镗刀杆基于ANSYS技术的优化设计的数学模型，并根据ANSYS8.0软件优化工具的功能对该数学模型进行了求解，优化结果表明：该方法是进行镗刀杆设计的一种科学实用的方法，对提高镗刀杆的设计精度有着重要的影响。

Based on the detailed analyzing of impact system working process, the differential eguation of the system was got, and the mathematical model of the hydraulic impact system was builted, on basis of the mathematical model, By using of dynamic simulation function of Matlab ,the author has built the simulation model of the impact system based on software Simulink and run it after inputting the parameter ,the dynamic graph curve of impact velocity and presser of oil and position of knife rest were got, and the dynamic characteristic of impact system was analyzed,the simulated results are accorded with the fact,and some rational parameters can be found.

在对冲击式采煤机液压冲击系统工作过程进行详细分析的基础上，运用微分方程建模方法，建立了液压冲击系统的数学模型即系统的动态方程，并在该数学模型的基础上，采用Matlab中的Simulink动态仿真功能，建立了基于Simulink的冲击系统仿真模型，通过给定冲击式采煤机冲击系统的相关参数，对该系统进行仿真，得到了冲击式采煤机工作过程中冲击速度和油液压力以及刀架位移的变化曲线，进而对冲击系统的动态特性进行了分析，结果与实际情况较为吻合，并由此得出某些合理的参数。

This paper mainly introduces several different methods to prove the mid-value theorem, at the same time the mid-value theorem is applied in the mathematical theory, such as the application and mathematical modeling.

本文主要推荐几种不同的方法证明微分中值定理，同时对微分中值定理加以应用，如在数学理论中和数学建模中的应用。

We will introduce some definitions in the Mathematics Ecology and the mathematical theories and methods. Methods for studding the population ecology or the more ordinary ecology are by setting up the mathematical modelings. We will give the examples of the single population models and the population with interaction models.

简单介绍数学生态学中的一些常用的名词和研究问题所用的数学手段-通过数学建模的方法，将一个实际的生态问题量化为一个数学问题，给出常用的单种群增长的数学模型和具有种间关系的多种群数学模型。

On the base of building mathematical models of tractive performance and economic performance, synthetical optimization model of transmission parameters is presented;And building mathematical models of flexibility coefficient of correlative parame...

其次，基于动力传动系参数优化及分析模型的建立，结合MATLAB与Visual C++编程语言的各自优点，开发了一套基于PC机的动力传动系参数分析及优化设计软件。

On the basis of the mathematical models got by different measuring methods, a complete universal mathematical model was put forward by which different tappets lifts can be converted from one to another.

针对凸轮升程测量量具及方法不统一而造成升程转换困难及转换误差较大等问题，在研究凸轮升程各种测量方法数学模型的基础上，提出一个不同形式推杆升程相互转换的通用数学模型。

The dynamical and kinematic specialty of hydraulic hammer is analyzed during piling. At the same time, the mathematical model is presented of each process. Based on mathematical model of each stage, simulation and analysis is made. The changing rule of displacement, velocity, acceleration can come to a decision from simulation plot during falling process of pile hammer.

提出桩锤在各个打击过程中的数学模型，并对各阶段进行仿真及分析，研究桩锤下打过程中，桩锤位移、速度、加速度变化规律，为进一步研究生产样机提供了理论依据。

A 3D two-fluid model is also built in order to describe more accurately the fluid flow on distillation trays by comparing the computational results of quasi-single phase mathematical model with of two-fluid mathematical model.

本文采用有限体积法及计算流体力学软件&STAR-CD&对单块板以及首次对全回流下的全塔流体流动、传质过程进行了计算，计算结果如下：1。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。