查询词典 mathematical model

The main work and the originality points of this dissertation could be concluded as the following parts:(1) To analyze systematically the mathematical model of LES of air flow in great space, under the case of isothermal and non-isothermal, as well as the combined action of buoyancy and strain. Some basic problems are studied about the LES application into airflow simulation of great space, such as boundary conditions, spatial difference scheme and time advancing scheme, time step etc., which creates the basis for the LES application to indoor airflow simulation.(2) Both the instantaneous and time averaged flow field of great space with multiple jets under isothermal and non-isothermal cases are explored with large eddy simulation method, and also discussed the dynamic characteristics and the law of fluidflow in the great space.(3) Based on the results of LES of the great space and the Fanger thermal comfort indexes, it is brought forward the concept of the series of dynamic thermal comfort evaluating indexes, which could be divided into thermal comfort index with time averaged properties PD, PPD, PMV, thermal comfort index with instantaneous properties IPD, IPPD, IPMV, and time averaged thermal comfort indexes TAPD, TAPPD, TAPMV, and transient situations time averaged thermal comfort indexes TTAPD, TTAPPD, TTAPMV. The differences among them and the calculation methods are discussed, and the four kinds of indexes are calculated with the thermal comfort index PD as an example.(4) Based on the LES results it is discussed the hot air stratification phenomena in air-conditioned buildings in the case with air supply and return registers on the ceiling and the case on the sidewall. The fundamentals of the hot air stratification are studied and the relations of estimating hot air stratification are brought forward.(5) With the advanced apparatus such as hot wire film anemometer IFA300 and laser particle field anemoscope, corresponding model test and site measurements have been done, which are compared with the simulation results and LES is proved a very promising method in air flow simulation indoor.

本文主要工作既创新点体现在以下几个方面：(1)系统分析了等温、非等温和考虑剪切力与浮升力综合作用的高大空间大涡模拟数学模型，并研究了高大空间大涡模拟在室内气流仿真应用中的一些基本问题，如边界条件、空间离散格式和时间推进格式、时间步长选择等问题，为大涡模拟在室内气流计算中的广泛应用打下了基础；(2)首次用大涡模拟方法研究了高雷诺数下高大空间多射流在等温、非等温情况下的瞬时流场和时均流场分布，并探讨了多射流流场的动态特性和流动规律；(3)基于大涡模拟的动态仿真结果和Fanger的热舒适指标，首次系统地提出了动态热舒适评价指标体系的概念：即基于时间平均参数的热舒适指标PD、PPD、PMV；基于瞬时参数的瞬时热指标IPD、IPPD、IPMV；基于时间平均热舒适指标TAPD、TAPPD、TAPMV；以及沿行动迹线的时间平均热舒适指标TTAPD、TTAPPD、TTAPMV，并分析了四类热舒适指标的差异性和计算方法，还以PD值为例对四类指标分别进行了计算；(4)基于数十种工况下空调房间大涡模拟的结果，研究了空调建筑上送上回和侧送侧回两种情况下热分层现象，并探讨了热分层的基本规律，首次提出了避免热分层现象的判断公式；(5)在暖通空调领域，首次使用IFA300热线风速仪、激光粒子速度场仪等先进设备，完成了与大涡模拟相对应的模型试验，并把实测结果与仿真结果进行了对比，说明LES在室内气流仿真方面是一种很有前景的方法。

The mathematical model was verified in experiment with the method of indirect squeeze cast Archimedean spiral proof sample. And the experimental results show that the maximum deviation between the theoretical value and measured value is less than 8%. This model can be used for quantitative analysis and estimating effects of the craft factors on the filling ability, and can also predict the maximum filling length. It has the important reference value to design the semi-solid alloy rheoforming technology and mould.

采用间接挤压铸造阿基米德螺旋线试样的方法对该数学模型进行了实验验证，实验结果表明：理论计算值与实验测定值之间的最大偏差小于8%；该数学模型可以定量分析和估算工艺因素对充型能力的影响，并可预测充型极限长度，这对半固态合金流变成形工艺设计和模具设计都有参考价值。

Bilinear transformation was adopted to discrete the mathematic model of the whole simulation system. Considered that LabVIEW was a novel graphic computer language, the practical realization of mathematical model in LabVIEW was presented.

首先采用频率预曲折双线性变换法将控制系统的数学模型离散化；然后在LabVIEW中进行图形化编程，从而实现了基于虚拟仪器的汽轮机系统的仿真。

This model can be used to determine the proper angle and position of lance. In Chapter Five, based on characteristics of Pulverized coal combustion in blast furnace, the mathematical model in the blowpipe and the raceway, including coal movement, devolatilization and combustion, was put forward.

为消除对高炉风口磨损，本章结合高炉喷吹煤粉特点，发展了一个能全面考虑气固两相流煤粉燃烧和煤粉颗粒轨迹的三维计算程序，并对所采用的理论进行了详细介绍。

On the basis of slip-diffusion model of multiphase flow, a three-dimensional mathematical model of gas-particle flow in blowpipe has been developed and debugged to calculate the gas-solid two phases flow, including gas velocity and particle velocity inside the blowpipe.

运用多相流的拟流体模型建立了高炉局部富氧喷煤直吹管内气粉两相流动的数学模型，对气粉两相流场进行了数值研究，探讨了气相和煤粉的速度分布规律及其影响因素，其中包括氧-煤喷枪的结构、漩流数和富氧率等。

An analysis of mathematical model of air distribution plate resistance was carried out for model HG CFB35 3.82/450 1 CFB boiler with the said plate resistance being test.

分析了循环流化床锅炉布风板阻力的数学模型，并对HG－CFB35－3.82／450－1型锅炉布风板阻力进行了测试。

In this research a new mathematical model - cubic polynom with two given derivatives at end points - was proposed which can good match the S-shpae curve.This model has a number of analytical features:describing the geographic phinomena prosesses in three hierarchies (textural fractal,structural fractal and state fractal); the boundary values of the structural fractal can be considered as the boundary values of interval of scaleless.

在研究中提出了扩展分维表达函数：带导数三次多项式，它能很好地表达反S形分布曲线，具有一系列解析特征：可从三个层次（纹理分形、结构分形和态势分形）上描述地理现象或过程；其中结构分形的边界可近似地看作是非扩展分维无标度区的上下界。

We have developed a three dimensional (3D) compositional mathematical model for two phase flow and derived a new 3D streamline model with capillarity and gravity effects.

在建立起可动凝胶深部调驱的油水两相多组分数学模型的基础上，推导出了考虑重力和毛管力的三维流线模型，将求解饱和度的三维问题转化为一维问题。

The function of the addition of co-substrate ethanol was to in-situ regenerate NADH. A mathematical model was derived, in which, two substrates were catalytically reacted in sequence. The model was applied to the system involving the reduction of 2'-chloroacetophenone to R-2'-chloro-1-phenyl-ethanol by S.

深入研究了在乙醇存在下生物还原过程中酵母细胞内NADH、NAD〓、NADPH及NADP〓浓度的变化规律，发现胞内NADPH浓度迅速降低到零，而NADH浓度始终维持在较高水平，证明了用于底物还原反应的辅酶是NADH，辅助底物乙醇的加入有利于实现辅酶Ⅰ的原位再生。

For confirming the method's efficiency, the turn-off transient mathematical model based on the chopper circuit is developed according to the proposed mathematic model of the turn-off transient current through IGCT, in which the RC-snubbers of IGCT, the stray inductance of chopper circuit and DC-link choke are taken into accounts.

该文建立基于斩波电路的IGCT关断暂态特性的数学模型。该模型充分考虑IGCT阻容吸收回路、线路杂散电感及限流电抗器对IGCT关断暂态过电压的影响。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。