结构函数

The calculating of its normal depth and critical water depth have no explicit function.

U形渠道断面水力和结构性能优越，是渠道输水工程中较常采用的断面形式之一，水力计算中的正常水深、临界水深求解无显函数形式的表达公式。

Based on a series of signal process and noise source identification techniques, especially the major noise source identification methods, such as expurgation method, sound intensity analysis, spectrum analysis vibro-acoustic correlation analysis and so on, the pass-by noise control of SC7080A and SC6360B are studied in detail. By the roadway and dais experiments, the major noise and radiating parts are identified and some economical controlling methods are made. For the SC7080A, to control the emissing noise from the intake and shell vibration of air cleaner, a intake muffler is installed between the air cleaner and intake valve. Based on the theory of Helmholtz resonator, One three-parallel-connected resonant silencer is designed and trial-manufactured. For the SC6360B, the attenuation performance of exhaust muffler in high frequency region is improved. To reduce the vibration noise of shell part, the structure of oil sump tank, exhaust manifold shield and exhaust manifold shield are analyzed and improved. At the same time, some measures, such as sound absorption, sound insulation, are taken to reduce the noise of engine surface emissivity and a sound shield is designed.

本文首先综述了目前国内外汽车加速噪声控制的现状、主要方法和技术措施，在此基础上，结合SC7080A和SC6350B汽车的车外加速噪声水平及现状，综合运用分别运行法、声强法、频谱分析法、声振相干函数法等现代噪声源识别方法，对SC7080A和SC6360B汽车进行了准确详细的车外加速噪声源识别并提出了经济可行的控制方案，针对SC7080A，主要在空气滤清器和进气阀门之间的进气管道上加装进气消声器，抑制空气滤清器壳体表面和进气口两处的噪声辐射，根据Helmholtz共振腔原理设计了三腔并联旁支型共振消声器，并进行了工程化设计和试制；针对SC6360B，主要改善了排气消声器在高频段的消声性能，对罩壳类零件进行了结构改进，降低了其表面噪声的辐射，并对发动机舱进行了吸声、隔声处理，设计了发动机隔声罩。

The control-augmented structural synthesis is an extreme value problem of the multi-peaks function, in which multiple optimal or near-optimal solutions are existed.

对于压电耦合结构、控制一体化设计这类多峰值函数的极值问题，有多个相等或不等的最优解〔次优解〕，因此得到不同的可替代解具有很大的实用性。

Takingthe contact stress, bend stress stiffness and temperature stress as thecondition, taking the weight of the kiln tyre as optimization aim function, theredia and the width of the tyre are optimized General optimize methods justconsider the affecting of the parameters to aim function, but in fact,structural parameters(such as structure dimension, interval and so on),physics and dynamics (damp factor, conduct factor, friction factor material'selastic module strength limits and so on), which would be changed afterused.

一般的优化方法，仅仅考虑了参数对其目标函数的影响，而实际情况下有些参数是变化的，产品的结构参数、物理和力学参数如阻尼系数、传导系数、磨擦系数、材料的弹性模量和强度极限等的设计值与制造后和使用中的实际值会有差异，这种差异称为设计变量和噪声因素的变差。

A efficient LU decomposition method is spectral factorization. That is, after the minimum phase correlative function of each array of matrix had be given by a spectral factorization method, all of the functions are arranged in a position according to its former location to get a lower triangular matrix.

谱法LU分解的优点是在对大量具有相同非零结构的矩阵分解时，通过建立包含所有具有不同非零元素的列对应的自相关函数的分解表，使得随后的所有矩阵分解只需通过查表实现。

In the end, the main content of this dissertation is addressed.In chapter 2, based on the analysis of present vibrators principle and structure, two kinds of transfer functions and frequency response curves of the vibrator, driven by voltage feedback power amplifier and current feedback amplifier, are given separately. And turnover frequencies between different frequency rangs are also given.

第二章分析了标准振动台的工作原理和结构，在此基础上，建立了标准振动台的机械和电气方程，给出了恒压源和恒流源功放激励下的振动台传递函数及幅频、相频特性曲线，列出了不同频段间的转折频率。

A fast finite mixture density function based adaptive importance sampling method is proposed to analysis structure failure probability and reliability sensitivity.

提出一种高效的基于混合密度函数的自适应重要抽样法，分析结构的失效概率及偏导型可靠性灵敏度。

In this article two functional modes of the Fly-back Converter (Continuous Conduct Mode and Discontinuous Conduct Mode) are particularly analyzed, which include their characteristics, applications, the critical pattern of two functional modes is argued, both the exact boundary from the angle of circuit parameters is crystallized, at the same time, basic principle of PFC under the DCM mode is introduced, which settle theoretical basis for the subsequent design; by establishing the mathematic model of the converter, a further investigation of the configuration is made, qualitatively and quantitatively, analyzed to settle exactly theoretical basis for the subsequent emulation and the experimental parameter; from the angle of steady-state analysis, the transfer function of the system is deduced to establish dynamic small-signal state equation, emulating the system with the help of matlab, then according to the simulation result and the theory of PFC revise the system, lastly, we adopt the project which add a zero-pole compensator to the voltage loop, by this way, a satisfied system performance is gained and the PFC scheme is ensured successfully; finally, based on the previously-done work, we combining with the situation of specific design requirement, acquired the numerical value of each unit devices in this converter

详细分析了反激式变换器的两种工作状态，连续模式(Continuous Conduct Mode ，简称CCM)和断续模式(Discontinuous Conduct Mode，简称DCM)以及各自的特点、应用场合，论证了两种工作状态的临界模式，从电路参数的角度明确了二者的界限，同时还介绍了DCM模式下PFC的基本原理，为后面的设计奠定理论基础；通过对整个变换器系统建立准确的数学模型，对此变换器的电路结构做了进一步的研究，定性、定量地分析了变换器各部分的工作状态，为仿真和实验参数的确定以及电路参数的优化提供理论依据；从稳态分析的角度，为系统建立了动态小信号状态方程并推导出系统的传递函数，利用matlab对系统进行仿真，进而根据仿真结果以及PFC的相关理论对系统进行校正，采用在电压环加入零点—极点补偿器的设计方案，得到了满意的系统特性并且保证了PFC的顺利实现；最后，在前面所做工作的基础上，结合设计要求计算出此变换器系统中每个元器件的数值，利用Pspice对其进行了仿真、优化，然后根据仿真结果搭建了硬件电路。

This paper takes dynamic ice force function as the cut-in point to solve theice-induced structural vibration.

本文以确定冰激结构稳态响应下的激励函数作为解决冰激振动的切入点。

In order to know more about the microcosmic structure of the important biochemical model molecule formamide in aqueous solution, the Optimized Potentials for Liquid Simulations-All Atom model were used in the molecular dynamics simulation for the aqueous solution of FM in the whole concentration range. The radial distribution functions of the solutions were obtained. The interaction between water molecule and FM molecule was analyzed and calculated.

为了解重要的生化模型甲酰胺在水溶液中的微观结构，采用全原子力场在全浓度范围内对甲酰胺溶液进行了分子动力学模拟，得到了溶液的径向分布函数，分析计算了溶质和溶剂分子间的相互作用，对甲酰胺和水分子的氢键缔合情况进行了分析。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。