模型
- 与 模型 相关的网络例句 [注:此内容来源于网络,仅供参考]
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This paper aims to investigate structural health monitoring oriented finite element modeling for the tower of long-span bridges.
首先采用不同的方法分别建立了大跨桥梁索塔的精细有限元模型和简化模型,运用环境振动实测结果对简化有限元模型进行了修正,并和精细模型计算结果相比较;研究结果表明:严格按照设计图纸建立的精细有限元模型计算得到的动力特性与索塔现场环境振动实测值之间的误差较小,而未经修正的简化模型误差较大,由此说明:大跨桥梁在有限元建模时应尽可能详细地反映结构的几何与材料特性,在此前提下,对于设计资料全面的桥梁结构,建立有限元模型时就只需要修正那些无法用数学和物理方法模拟的不确定因素。
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In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.
本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究,得出了许多有价值的结论,主要概括如下: 1、阐述了目前针对超声电机压电振子的主要建模方法,对压电振子动态特性的研究意义和必要性进行了论述,突出了本文研究内容的迫切性; 2、以压电陶瓷诱发弹性体发生弯曲变形为例,分析了压电陶瓷通过诱发应变来实现机电能量转换的机理;对基于纵弯模式的压电振子的运动及动力传递机理进行了分析; 3、基于模态假定,利用分析动力学的Hamilton原理,建立了面向直线超声电机压电振子的机电耦合动力学模型,并据此建立了压电振子的等效电路模型,导出了电参量与动力学特性参量的耦合方程,为压电振子与驱动电路的匹配提供了依据; 4、从压电陶瓷的本构方程出发,综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程,采用虚位移原理,建立了压电振子动态问题机电耦合场求解的有限元控制方程,为研究其大功率驱动下的非线性本构模型奠定了基础; 5、界定压电振子的动力学特性指标,对压电振子的机电耦合动力学模型参数进行计算及变参数仿真;依据等效电路模型,对压电振子的电学特性进行了仿真分析;通过有限元数值实验,对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析,找出了实现模态简并的激振频率;利用有限元控制方程,通过编程计算,对压电振子的力电耦合场参数进行了详细计算,得出了一些有价值的结论。
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According to the characteristics presented by armed helicopters during cruising or searching for ground targets, this paper has established the mean-square deviation stationary random model of helicopter tracks. It is an important method to decorrelate the measure noise by estimating the parameters of the color noise online. Kalman filtering and forecasting have been made with helicopter tracks. The simulated study has been carried out on helicopter tracks under the condition of color noise. It is very difficult to get an accurate and reliable prediction when the data is very limited. The paper make use of the theory of grey system to resolve the problem of prediction of helicopter tracks, establishing the GM model of grey systems and the cumulative residual error model of n degree, then correcting the GM forecast model. In the period of sampling, GM model and residual error model have been established on line to improve prediction precision.
结合武装直升机在巡航或搜索地面目标的特点,给出直升机航迹模型为协方差平稳随机模型,在线估计有色噪声参数,对测量噪声去相关,对直升机航迹进行卡尔曼滤波与预估,最后对有色噪声条件下的航迹进行了仿真研究;在数据非常有限的情况下,准确地预测又很困难,本文提出了用灰色系统理论解决直升机航迹预测问题,建立了灰色系统GM预测模型和n次累加残差模型并对GM预测模型进行修正,在每个采样期间内,实时在线建立GM预测模型和残差模型以提高预测精度。
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The basic theories of mathematical morphology for binary image are stated, and the most simple structure elements of morphologic transformation for binary images are proposed and proved. The geodetic morphologic transformation models are also developed. For the purpose of improving the speed of transformation in computer, the"set symmetric difference"is introduced to adapt each model. Some new morphologic filtering models and quantitative evaluating model of filtering effects in image processing are proposed, under the applied condition. The morphologic thinning methods are studied, and two new morphologic thinning models are developed. On the basis of analyzing the characteristics of mining maps, the image vectorizing tactics and a series of algorithms are proposed, including dynamic adaptive image thresholding using two thresholds, graphic and text separation, noise removal, and multi elements extracting models with mathematical morphology. Accuracy preserving compressed vectorizing model for image vectorization is put forward to generate vector data in multi layer.
论文对二值图象形态学的基础理论进行了较系统的阐述,提出并证明了二值图象处理中形态变换的最简单结构元素,并发展了测地形态变换模型;为了提高形态变换的计算机实现速度,引入了集合论中"对称差"的概念对各形态变换模型进行了改化;针对数学形态学在图象处理中的实际应用,提出了新的形态滤波模型及滤波效果的度量评价模型;研究了形态细化方法,提出了快速形态细化和保形快速形态细化算法;在研究矿图基本特征基础上,提出了人机协同矿图扫描图象矢量化处理策略及一系列扫描图象处理算法模型,包括双阈值动态自适应图象二值化、图文分离、噪声去除、图面多种要素提取形态变换模型等;在图象栅格—矢量转换中,提出了保精度压缩矢量化模型,以生成分层要素矢量数据。
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Then the alveolar bone of model 1 was lowered to respectively construct Model 2(Bone loss was one fourth of the root), Model 3(Bone loss was one third of the root), Model 4(Bone loss was the half of the root), Model 5 (Bone loss was the two third of the root) and Model 6 (Bone loss was the three fourth of the root).
在模型1基础上,将牙槽骨骨高度分别删除1层、2层、3层、4层、5层(使处理后的牙槽骨骨高度与牙根长度之比由1:1变为3:4、2:3、1:2、1:3、1:4),产生模型2、模型3、模型4、模型5、模型6,代表五种不同程度的牙槽骨骨吸收模型。
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The Markov forecast model, time series method (triple exponential smoothing method and a combined of triple exponential smoothing method and Markov model) and stepwise regression forecast method were choosed, and the basic principles and processes of the three models were analyzed and compared. Based on above, the three methods were used to predict population dynamic of Cricetulus barabansis and Meriones unguiculatus. The characteristic, accuracy and applicability of three methods were analysed and compared. The results showed that,(1) Markov model belongs to a middle-long time forecast model, and the result was interval forecast, but it reached the requirement of forecasting the harmful population dynamic of rodents. Through the forecasted population dynamic of Cricetulus barabansis and Meriones unguiculatus in 2004, the results were accurate; this meant that Markov model was a good forecast model to Cricetulus barabansis and Meriones unguiculatus population.
选择马尔可夫链预测模型、时间序列分析法(三次指数平滑法、三次指数平滑法和马尔可夫链预测模型的组合预测法)和逐步回归预测法,对这三种模型的基本原理、模型的构建过程进行对比分析,在此基础上用此三种方法预测了黑线仓鼠和长爪沙鼠的种群数量,并对三种方法的特点、预测的准确度和适用范围进行了比较分析,结果表明:(1)马尔可夫链预测模型属于中长期预测,预测的结果为区间预测,但对于害鼠种群数量的预测来说已经达到要求,通过对2004年黑线仓鼠和长爪沙鼠种群数量的预测,预测的结果都比较准确,这说明对于预测黑线仓鼠和长爪沙鼠种群的数量动态,马尔可夫链模型是比较好的模型。
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The graph in isometric drawing must be consistent with the topology relations in the threedimensional model, but not be drawn in one uniform scale. Based on the result of analyzing the rules in isometric drawing, the templatebased method is proposed for representing the different and unrelated drawing rules in an uniformed way.
ISO图模型的建立:针对ISO图的自动生成时所需的工厂管道的三维模型和二维图纸模型的统一性要求,提出了一种基于点线关系模型的二三维一体化模型解决方案,把三维空间中工厂管道模型和二维图纸空间中的管道图形统一起来,为二三维模型中的各种功能提供了基础。
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Moreover,the NRTL and UNIQUAC models,of which theinteraction parameters were expressed as afunction of the temperature from 298.2Kto 348.2K,were respectively used to correlate the LLE data in the range of 298.2K to348.2K for each binary system.The results show that the correlation accuracy of theUNIQUAC model is better than that of the NRTL model and is satisfactory.
为了便于应用,将NRTL模型和UNIQUAC模型中的参数表达成温度的一次函数对每个系统在不同温度下的互溶度数据同时进行了关联,结果发现三个系统的UNIQUAC模型的目标函数值均要小于NRTL模型的目标函数值,且UNIQUAC模型计算互溶度与实验值的偏差小于NRTL模型的计算偏差,UNIQUAC模型的关联精度是令人满意的。
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Anharmonic vibronic oscillator model, two levels model, bond parameter model and bond charge model were established in 1960's, which came from classical or qualitative concepts.
非谐振子模型,双能级模型,键参数模型,键电荷模型,电荷转移模型,阴离子基团模型,双重基元模型。
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Based on them, this paper proposes evaluation indexof fund performance from the aspect of finance, investor and interiormanagement. Considering the limitation of data envelopment analysis approach usedto evaluate fund performance, such as conventional DEA models can not considerinputs and outputs of evaluation units simultaneously, and an input-oriented DEAmodel and output-oriented DEA model often produce different evaluation results,this paper proposes a general form of DEA model which is input- andoutput-oriented by using multi-objective optimization and fuzzy set theory. Sincethe general form of DEA model can be transformed into a conventional input oroutput oriented DEA model by using special membership functions, it can beseemed as a nature extense of conventional DEA models, and a conventionalmodel can be regarded as a special case of DEA mdoel with general form.
针对现有基金绩效评价方法中较具优越性的数据包络分析方法的不足,如传统DEA模型不能同时综合考虑评价单元的输入和输出,以及分别采用面向输入和面向输出DEA模型评价基金绩效时,常常出现不一致的评价结果等,本文以多目标优化与模糊集合理论为工具,提出了一种能够同时面向输入和输出的DEA一般形式模型,并通过选择一些特殊的模糊集合隶属函数,使得这种DEA一般形式模型成为传统DEA模型的自然推广,而传统DEA模型是该模型的特殊形式。
- 推荐网络例句
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As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.
每逢看到沃林顿那刚毅的脸,那乌黑、忧郁的眼睛,她便会相信,他一定作过不幸的爱情的受害者。
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Maybe they'll disappear into a pothole.
也许他们将在壶穴里消失
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But because of its youthful corporate culture—most people are hustled out of the door in their mid-40s—it had no one to send.
但是因为该公司年轻的企业文化——大多数员工在40来岁的时候都被请出公司——一时间没有好的人选。