查询词典 periodic error

For Lienard equation X +fx'+ ex = e, we obtain that if and for any periodic function or almost periodic function e it has a periodic solution or an almost periodic solution.

而对于Lienard方程x＋fx'＋cx＝e，我们得到：当c＞0且时，对于任意周期、或概周期函数e，它有周期或概周期解。

A main feature in developing the theory is that the scope is expanding: from almost periodic function, asymptotically almost periodic function, weakly almost periodic function to pseudo almost periodic function which was introduced by Professor Zhang in 1992. Every extension consumedly enlarges the theory and their applications.

从概周期函数、渐进概周期函数、弱概周期函数，一直到张传义教授在上世纪九十年代初提出的伪概周期函数，每一次函数范围的扩展都大大地丰富了概周期函数的理论和其应用前景。

For some special cases, the paper gives some important identical theorems, and then establishes a valuable relation between the uniformly almost periodic functions and the trigonometric polynomials.Secondly, on the basis of the identical theorem, the paper investigates the Fourier series of the uniformly B2 almost periodic functions, and further proves that the series is unique.Thirdly, the paper discusses the Parseval equation of the uniformly B2 almost periodic functions, which establishes the relation between these functions and the coefficients of their Fourier series; and next investigates an important approximation theorem-Riesc-Fischer theorem, about the uniformly B2 almost periodic functions and the trigonometric polynomials.

并给出了特殊情况下的几个重要的恒同定理，将一致概周期函数与有限三角多项式联系起来；第二，在恒同定理的基础上，给出了一致B~2概周期函数的Fourier级数，并且级数是唯一的；第三，讨论了一致B~2概周期函数的Parseval方程，建立了函数与其Fourier级数的系数之间的联系；接着给出了关于一致B~2概周期函数和三角多项式之间的一个重要近似定理—Riesc-Fischer定理。

On the applications of the uniformly Besicovitch almost periodic functions to differential equations, the main works are as follows:First, the paper proves that the space of the uniformly B2 almost periodic functions, with a special norm, is a Banach space, and then the Fixed Point Methods could be used in this function space.Second, since the space of the uniformly B2 almost periodic functions is per-fect, the paper investigates the existence and uniqueness of uniformly B2 almost periodic solution of a wave equation involving reflection of the argument by the principle of contraction mapping.

关于一致Besicovitch概周期函数在微分方程中的应用，本文主要做了以下工作：第一，证明了一致B~2概周期函数空间在其特定范数下构成Banach空间，从而可以在此函数空间上应用不动点定理；第二，由一致B~2概周期函数空间的完备性，应用压缩映像原理，讨论了一类满足一定初始条件的带反射变量的波方程一致B~2概周期解的存在唯一性。

The instability originated in the upper R_B-like convection zone develops to larger region with the increase of Grashof number, and the number of non-axi-symmetric circulations decreases. When Grashof number exceeds another critical value, cooling air may invade the cavity and flow toward the shroud, the circulations decrease to one pair occupying the whole cavity in radial, thus these two zones are merged into one. The core structures in the cavity rotate against the disks, while the structures keep no change at the case of periodic oscillatory flow. With the Grashof number rises, the flow undergoes stable, periodic, periodic with cool air invading, quasi-periodic and ultimately to chaos.

离心浮升力是造成非等温轴向通流旋转盘腔内流动不稳定的主要因素，而哥氏力的存在加剧了流动不稳定性，导致流场失稳提前发生，而且在哥氏力的作用下流线发生偏转，盘腔内r-θ面出现了旋向相反的对涡，流动结构更加复杂化；随离心浮升力的继续增加，r-θ面的对涡减少，当其超过某一临界值后部分冷流体侵入盘腔，对涡减少至一对，而且沿径向充满整个盘腔；此后随离心浮升力的增加对涡的数量不再变化；r-θ面的对涡相对于盘面周向移动，但是形状基本保持不变。

By using theories of almost type functions,the theorem about relation of asymptotically periodic functions and asymptotically periodic sequences ,as well as the equipollence of vector-valued asymptotically periodic functions and almost periodic functions on R+ are obtained.

利用概周期型函数的理论，得出了渐近周期函数和渐近周期序列二者的关系定理，以及R+上的向量值渐近周期函数与概周期函数的等价关系。研究了渐近强周期函数空间、渐近周期序列空间的可分性质

We calculated the main effective second order nonlinear optical coefficients of the 〓 quasperiodic superlattice, analyzed the relationship between them and the quasi-periodic structure parameters, studied the extinction phenomenon and the extinction rules in quasi-periodic structure, standardized the expression of frequency conversion in homogenous crystal, periodic and quasi periodic superlattice crystal.

计算了〓准周期超晶格的有效二阶非线性系数，研究了它与准周期各结构参数之间的关系，分析了准周期结构中的消光规律，统一了频率转移效应在均匀材料、周期超晶格和准周期超晶格中的表述。

By Ensemble-averaged Method, the mean field was got to show the 3D structure of flow. By Phase-locked Averaged Technique, the periodic mean field was got to reflect the periodic unsteady characteristic. The 3D structure and the periodic unsteady characteristic of the unsteady flow within the vaneless and vaned diffuser were discussed through analyzing the mean field and the periodic mean field.

离心风机扩压器内非定常流动的实验研究本文完成了离心风机两种结构条件下无叶扩压器、有叶扩压器内部的非定常流动瞬态全流场的实验测量，获得了不同运行工况下PIV的瞬态流谱，为研究扩压器内部非定常流动提供了基础实验资料。

A high-speed digital-to-analog converter measurement method acquires and quantizes an analog ramp output by the DAC corresponding to a digital ramp input to produce a quantized ramp, determines a start and end of the quantized ramp, obtains a difference between the quantized ramp and an ideal ramp to produce a quantized periodic signal, determines a frequency for a qualified peak from an FFT of the quantized periodic signal, produces a mask filtered periodic signal from an iFFT around the qualified peak, and determines a sample window spanning a local maximum and minimum for each period of the quantized periodic signal.

一种高速模拟数字转换器测量方法，采集和量化由DAC输出的相应于数字斜坡输入的模拟斜坡以产生量化的斜坡，确定量化的斜坡的开始和结束，获得量化的斜坡和理想的斜坡之间的差值以产生量化的周期信号，从量化的周期信号的FFT中确定合格峰值的频率，从合格峰值周围的iFFT中产生屏蔽过滤的周期信号，并且在量化的周期信号的每一周期内确定跨越局部最大值和最小值的采样窗口。

Based on the return map and the principle of closed vectors, a new method is proposed to extract unstable periodic orbits embedded in chaotic attractors. As examples, the UPOs embedded in chaotic attractors of Logistic, Hénon and Lorenz are extracted respectively by this method. And our results of Skewed Hénon map also be compared with Nusse's. These results suggest that this method is valid for unstable periodic orbits from period one to period infinite of arbitrary dimension chaotic system. The dynamic considerations of spiking and UPO coding for individual neuron and neural system under external periodic and chaotic exciting stimulus also be studied in this dissertation. A lot of spiking phenomena, such as synchronization, period, and chaos appear alternatively with the changing of the stimulus frequency. For the small stimulus frequency the neuron could completely convey the periodic signal in synchronous anti-phase into interspike intervals sequences. For the slow time–scale chaotic input, the output two ISI sequences are reciprocally related to input signals, and their oscillation wave shape in time course can be derived from that of the input signals variation, furthermore, the similar input sequence and order of UPOs, distribution of LES and value of KYD remain in attractors reconstructed from ISI sequences.

发现周期信号在单个神经元传递过程中，随着激励频率的改变，神经元输出的峰峰间期interspike interval时间序列呈现出周期、混沌和准周期的交错变化，特别当外加激励信号频率较低时，周期信号可以通过神经元ISI序列以反相同步的周期运动形式传递下去；同时无论是周期还是混沌激励信号，在神经系统中的传递均与其自身强度和神经元之间的耦合强度的大小密切相关；快变时间尺度的混沌激励信号在耦合的神经系统传递过程中，会造成大量基本信息的丢失；而慢变时间尺度的混沌激励信号在神经系统传递中，它的非线性特征信息，如混沌吸引子、不稳定周期轨道、Lyapunov指数谱和分形维数，会通过系统输出的ISI序列部分地重现出来，如与输入慢变时间尺度的混沌激励信号相比，神经系统输出的ISI序列具有：相似几何形状的混沌吸引子、相近的Lyapunov指数谱和分形维数、局部结构相同的不稳定周期轨道的排列方式。

"Yes, now you can give yourself airs," she said, you have got what you wanted.

"对了，您现在高兴了，"她说道，这是您所期待的。

Then the LORD said to me: Rebel Israel is inwardly more just than traitorous Judah.

上主于是对我说：＂失节的以色列比失信的犹大，更显得正义。