查询词典 numerical analysis

By combining mathematical analysis with numerical simulation, we have shown that the Allee effect may be a destabilizing force in predator-prey systems: the equilibrium point of the system could be changed from stable to unstable or otherwise, the system, even when it is stable, will take much longer time to reach the stable state.

由于捕食者或猎物Allee效应的存在，系统的平衡点要么由渐进稳定变为中性稳定或不稳定，要么系统需要更长的时间才能到达平衡状态。

The plasma ignition threshold of metal is got through experimental and numerical study. The vapour and plasma ignition times of the target are got based on the equation of heat conduction and cascade model. We suppose that the plasma is ignited when generations of new electrons are born in vapour generation time. The influence of temperature on the thermodynamics and optics parameters of material also have been considered in the model. The resulting theory has good agreement with the experiment and overseas report. A blade method to measure the laser spot is given in this paper with validation and error analysis. The plasma threshold of metals in atmosphere and water ambients both are diagnosed with the light deflection and piezoelectric transducer. A Q-switched pulsed Nd:YAG laser operating at infrared (1064nm), visible(532nm) and ultraviolet (355nm) wavelengths has been used. Al、Fe、Cu are used as targets and get a similar results with both method. Theoretical and experimental analyses are applied on the influence of wavelength on the threshold have been done, both of which have shown that the plasma threshold of metals decrease as the laser wavelength increases; The plasma threshold of metals are higher in water than in air and the pressure of the shock wave in water is five times higher than in air .

从热传导方程和雪崩电离机制出发，假设当电子增值210倍时，考虑了温度对材料热力学和光学参数的影响时，得到了气化和等离子体点燃的时间，利用该模型进行计算得到的结果与国内外报道及自行通过实验测得的阈值基本一致；提出了利用刀刃法测量激光光斑面积的方法，并通过实验进行了验证和误差分析；利用光偏转装置和压电换能器分别对空气和水中金属等离子体点燃阈值进行了实验诊断，激光器均为调Q－YAG激光器（波长1064nm，532nm，355nm，脉宽10ns），靶材分别为Al、Fe和Cu，两种测试方法得到的等离子体点燃阈值基本一致；本文从实验和理论计算两个方面讨论了波长对等离子体点燃阈值的影响，均得到了等离子体点燃阈值随著波长的增加而减小的结论；对空气中和水中不同环境下金属等离子体的点燃阈值进行了比较研究，得到了金属在水中的等离子体点燃阈值比空气中的大，且水中产生的冲击波的压强是空气中的5倍左右的结论。

The results of theoretical analysis and numerical simulations showed that the micro sized inclusions whose volumes become larger because of agglomerating at antinodes can be removed further with horizontal ultrasound processing.

理论分析和数值模拟结果表明：利用水平超声波照射金属液时，其中的微小非金属夹杂物会凝聚于波腹，结成串或块状的大体积夹杂物，这有利于上浮分离，便于去除。

According to the effects of nonlinear potentials on symmetries and their strength distributions, one is able to predict the existing discrete breathers in a given system, which is real helpful to theoretical analysis and numerical calculation.

根据各非线性势能系数对解的对称性的影响以及不同大小的非线性势能函数对解的影响强度的分布，可以对特定系统中可能存在的离散呼吸子解进行预测。

Based on the results from the Kaiser effect test, disengagement density dislocation test calcspar mineral crystal lattice, and physical simulation results, the numerical simulation models are constructed, and the boundary conditions for simulation analysis is decided.

利用Kaiser效应、方解石矿物晶体的晶格自由密度位错的测试结果，结合物理模拟的结果，建立了研究区数值模拟分析的地质模型，确定了数值分析的边界条件。

With the technique of wavelets analysis and neural network intelligence, aiming at numerical calculation of temperature field in casting process of camshafts, the arithmetic of wavelet neural network is described.

利用小波分析和神经网络智能技术，针对凸轮轴铸造充型凝固过程的温度场数值求解问题，提出了小波神经网络算法。

Numerical classification and cladistic analysis were new ways in phylogenetics.

数值分类和支序分类是系统发育分析的两种新方法。

In the couping solution, based on the characteristics of the models in this dissertation, each of loading step is finished in unit time. Thus the volumetric strains on the current increment step as analysis parameters are inserted into the equation of continuity and a physical equation for pore water pressure is presented. The fundamental solutions of two kinds of classic problems (axial symmetry and plane strain) are derived. By use of the fundamental solutions of pore water pressure combined with finite element method of soil mechanics, a semi-analytical and semi-numerical method for nonlinear consolidation equations is presented.

在耦合分析中，根据本文模型的特点，将每一荷载增量步看作单位时间完成，对应当前增量步的体变分量作为分析参数代入连续方程，建立了基于数值模型的孔压变化方程，根据工程中最常见的两类问题推导出基本解，结合土骨架的控制方程建立了此类液-固耦合问题的半解析半数值解答体系，编制了有限元程序，从而实现了从建立本构关系到模拟固结问题的全数值方法。

Then, safety analysis method was constituted considered the typical damage of concrete beam bridge. 5. By amending the reduction rate of loading capacity used in Code for Maintenance of Highway Bridges and Culvers (JTG H11-2004), a new reliable index is presented in the same safety standard to reflect the relation between load and resistance. According to the basic principal of calibration method, the recommended gradation index was computed under various factors such as different load combinations, vehicle operating status and different failure modes. With these calculated numerical values, the calculated reliability indexes standard for the estimation of safety degree of in-service concrete girder bridge members was ultimately obtained.6. Based on the related standards and results on crack and displacement that cannot continue to loading at home and abroad, the evaluation grade of the concrete beam bridge is proposed by analogy.

针对材料和构件损伤对混凝土梁式桥抗力的影响，基于材料和构件层次典型损伤的修正计算公式，在结构既有以及时变抗力评估的概率模型基础上，通过误差传递公式获得抗力统计参数，对抗力进行修正，构成了考虑混凝土梁式桥典型损伤的安全性分析方法。5、依据校准法原理，将《公路桥涵养护规范》(JTG H11-2004)中不同类别承载力下降率转化为修改分项系数，分别计算了轴心受压、轴心受拉、受弯、大偏心受压、受剪构件在各种情况下的可靠指标，根据破坏类型对校准结果进行分析，提出了基于可靠度的公路混凝土梁式桥安全性评定等级。6、基于不能继续承载的裂缝和位移的相关国内外规范和研究成果分析，通过类比提出了混凝土梁式桥不能继续承载的裂缝和位移评定等级界限。

Under the guidance of Carl Marks\' dialectical and historical materialism, the author of the present dissertation, by using the fundamental theories and methods of regional and developmental economics, ekistics and statistics, makes a qualitative as well as quantitative analysis of the relationship between the development of talent resources and economic growth, drawing on relevant numerical models and research results published both at home and abroad.

本文以马克思辩证唯物主义和历史唯物主义理论为指导，运用区域经济学、发展经济学、人才学、统计学等学科的基本理论和方法，借鉴国内外人才资源开发与经济增长研究的理论成果与数量模型，采取实证分析与规范分析、定性分析与定量分析相结合的方法，分析了人才资源开发与经济增长之间的关系。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。