频率曲线

By using the infrared ray, a new kind of noncontact collector ring, named as noncontact infrared collector ring, is developed for the first time.

研究表明，最优的正弦修形曲线的角频率总是接近于齿轮啮合频率，初相位接近于π/2，为最优修形曲线的设计提供了一种新方法。

The cubic interpolation polynomial is got firstly in the given sub-range of the hydrophone's sensitivity-frequency curve by using the Akima curve smoothed algorithm, and the maximum of the polynomial is calculated in the sub-range by using the one dimension extreme value continued fraction algorithm, finally the frequency of the hydrophone is got.

频率测试是在灵敏度详细测试的基础上，采用阿克玛曲线光滑算法求出检波器幅频特性曲线在给定子区间上的三次插值多项式，再利用一维极值连分式法求出该区间上多项式的极值，从而求出检波器的频率值。

The results indicate that its dynamic stress-strain curve is hyperbolic type. The dynamic strain of LCES decreases with increasing confining pressure, cement content, curing ages and cyclic loading frequency when it is subjected to the same dynamic stress. At the same dynamic strain, the dynamic secant elastic modulus E_(sec of LCES increases and the damping ratio decreases with increasing confining pressure, cement content, curing ages and cyclic loading frequency. The curves ofσ_d～ε_d,E_～ε_d and D～ε_d with different EPS content intersect respectively, the trend of LCES deformation characteristic is inversely proportional to EPS content near the intersection. The value of dynamic strain at the intersection is about 0.5%~3.0%, the magnitude of which is related to the mixing proportions and confining pressure.

试验结果表明，LCES的动应力应变骨干曲线形态符合双曲线；在相同的动应力作用下，LCES产生的动应变随着固结压力、水泥掺量、试样养护龄期和振动频率的增大而减小；在动应变相同的情况下，随着固结压力、水泥掺量、试样养护龄期和振动频率的增大，LCES的动模量增大而阻尼比减小；随着加载次数的增大，LCES的动模量在开始阶段显著降低，然后趋于稳定，但当加载次数达到几百次时，动模量又有增大的趋势；不同EPS掺入比的LCES的动应力应变骨干曲线、动模量随应变变化曲线和阻尼比随应变变化曲线都发生了相交，交点前后EPS掺入比的大小对LCES动力变形特性的影响趋势是截然相反的，交点处的动应变值一般在0.5％～3.0％范围内变化，其大小与LCES的配比以及固结压力有关。

In the 65 recorded neurons, the results showed: Characteristic frequency , minimum threshold and response latency was between 18.9 and 76.7 kHz (42.94 ± 11.29), 29 and 80dB SPL (58.65 ± 12.62), 3.1 and 13.4 ms (6.10 ± 1.47), respectively; CFs increased with the recording depth, but CF and MT were not correlated; There were three different types of discharge patterns in the IC, including phasic pattern (73.9%), chopper (15.4%) and tonic (10.7%); The types of frequency tuning curves were all V-shaped, most of which were wide type and few were narrow type.

结果发现，在所得的65个下丘神经元中：特征频率在18.9～76.7kHz(42.94±11.29)之间，最小阈值在29～80dB SPL(58.65±12.62)之间，潜伏期在3.1～10.4ms(6.10±1.47)之间；特征频率随记录深度的增加而增大，与最小阈值之间没有显著相关性；发放类型包括相位型(73.9%)、梳齿型(15.4%)和紧张型(10.7%)3种基本类型；频率调谐曲线均为开峰型，多数神经元(72.3%)调谐曲线较宽阔，少数(27.7%)较狭窄，并且多数神经元的频率调谐曲线高频边比低频边陡。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

In the aspect of the study of the application of HHT method, This dissertation has done three part of jobs: first, the Elcentro strong ground motion which is in common use in earhtquake engineering is analyzed by HHT method, getting its amplitude-frequency-time distribution and the comparison between the HHT marginal spectrum and Fourier spectrum is also made; second, the typical nonlinear system defined by the Duffing equation is analyzed by HHT method, getting its numerical value's amplitude-frequency-time distribution and the comparison between the HHT marginal spectrum and Fourier spectrum is also made; third, define the stationary degree of non-stationary signals making use of 3-D time-frequency spectrum and marginal spectrum, the stationary degree curve of Elcentro seismic recording is protracted according to its defining formula, the stationary degree curve of Elcentro seismic recording which change with time is protracted according to similiar definition.

在HHT方法的应用研究方面，本文做了三部分的工作：首先，利用HHT方法分析了地震工程中常用的Elcentro非平稳强震记录，得到了该记录的振幅－频率－时间分布特性，并将得到的边际谱与傅立叶谱做了比较；其次，应用HHT方法分析了典型的非线性系统－Duffing方程，得到了该方程数值解的振幅－频率－时间分布特性，并将得到的边际谱与傅立叶谱做了比较；最后，利用三维时频谱与边际谱定义了非平稳信号的平稳度，并依照其定义式绘制了Elcentro地震波记录的平稳度曲线，依照类似与依赖与频率变化的平稳度定义，初步尝试编程绘制了Elcentro地震波随时间变化的平稳度曲线。

By Using CPB to analyze the sound insulation character, it show that when the cavity depth is 30mm, the sympathetic vibration exist around the centre frequency of 200Hz of the system, the frequency character contours of sound insulation represent a lowest value. While the cavity depth is 40mm

使用CPB分析材料组合系统的隔声特性，当空腔深度为30mm，系统在中心频率200Hz附近产生共振，隔声频率特性曲线在该位置形成一个低谷；当空腔深度为40mm，隔声频率特性曲线在中心频率为160Hz位置形成一个低谷。

On the other hand, with the purpose of fuzzy feature extraction and fuzzy classification device design, the undulatory property of maximum and minimum scattering power corresponding respectively to the maximum and minimum eigen-polarization has been investigated in frequency domain. Furthermore, the anisotropy polarization degree of target, which is determined by both maximum and minimum scattering power of target, has been studied; meanwhile, the dynamic changing characteristic of eigen-polarization on Poincare polarization sphere has been investigated by means of the conception of polarization frequency stability, the research result shows that PSD value has a big jump near π, forming a sharp pulse, and different target has their individual distribution property of PSD pulse.

另外，围绕目标模糊特征提取及模糊分类器的设计，研究了目标最大、最小本征极化所对应的目标最大、最小散射能量随观测频率的起伏特性，考察了由目标最大、最小散射能量共同决定的目标的各向异性极化程度；同时，采用极化频率稳定度的概念，研究了本征极化在Poincare极化球面上的动态变化特性，在最大、最小散射能量相等的频率点上，PSD曲线呈现为幅度接近π值的尖锐脉冲，反映了目标极化散射结构对这一频率跳变极为敏感，但不同目标的这种PSD曲线特征又有很大的不同。

; 3 younger Dryas Only has reflection in the hundred-year-scales climatic curve, it is not evident in the curve of long period; 4 in the hundred-year-scales climatic curve, the last glacial maximum fluctuation as frequuently and 18-28KaBP was the stage in which the frequency fluctuation was the largest.

；（3）新仙女木事件仅反映在百年尺度的气候曲线上，在较长周期的饿曲线上不明显；（4）在百年尺度的气候曲线中，末次冰盛期气候波动频繁，其中18-28KaBP 是频率波动的最大阶段，但随着周期尺度的加大，气候的波动频率逐渐趋于均匀。

Aturate interception of vegetation in woodland (forest canopy, understory and litter), annual stem flow, Maximum capillary moisture capacity in woodland, saturate infiltration rate of woodland soil, runoff modules of woodland, rainfall erosive force indices, annual river runoff volume and sediment delivery as well as their seasonal distribution, the maximum peak flood frequency curve

oil and water conservation forest 林地植被饱和截留量(林冠层+林地活地被物层+林地枯落层)，树干年径流量，林地土壤最大毛管持水量，林地土壤饱和入渗率，林地径流模数，降雨侵蚀力指标，林地土壤侵蚀模数，河道年径流量和输沙量及其季节分配，河道最大洪峰流量频率曲线

Do not gum up the work by telling mother what we are going to do .

别告诉母亲我们要干的事，那会把事情搞糟的。

In recent years, application of the partial prestressed concrete beam s is developed.

近年来，随着部分预应力砼梁应用的推广，发现我国规范所采用的名义拉应力法的计算结果不稳定。