离散的

We obtain that if any 〓 is discrete or elementaryand 〓 satisfies Condition A,then the algebraic limit G of group sequence 〓is discrete or elementary.

首先，我们不再仅仅考虑离散非初等群集〓的代数极限G，而是离散群或初等群群集〓的代数极限G，我们对〓上〓变换群中斜驶元及其不动点进行了细致研究，注意到任意一个斜驶元存在一个仅仅含有斜驶元的领域，从而证明了初等群群集〓的代数极限G仍然是初等群，进而我们得到了一个代数收敛定理：如果任一〓是离散群或者初等群并且〓满足条件A，那么，群列〓的代数极限G一定是离散群或者初等群。

The basic concept in these sections is replacing backward Euler's method by modified backward Eulers's method to approximate the characteristic differential equation and discretizing the convection-diffusion equation at the middle point of the approximate characteristic curve, which will make the convective term get up to second order accuracy.

这三节的基本离散方法是用改进的Euler公式代替向后Euler公式来近似特征微分方程，并且将近似特征线的中点作为离散节点，使得对流项的离散精度提高到二阶，对于扩散项，将其转移到待求时间层进行离散。

The basic idea is to set a continuous solution of the region with a finite number of discrete points instead of a grid consisting of, these discrete points called grid nodes the solution of a continuous area on a given function of continuous variables used in the definition of discrete grid variable function approximation the original equation and boundary conditions in the micro-business operators to approximate differential, integral with the points and to approximate, so the original differential equations and boundary conditions are replaced by algebraic equations near Side, that is, finite difference equations , solve this equation group can get the original problem in discrete points on the approximate solution.

基本思想是把连续的定解区域用有限个离散点构成的网格来代替，这些离散点称作网格的节点；把连续定解区域上的连续变量的函数用在网格上定义的离散变量函数来近似；把原方程和定解条件中的微商用差商来近似，积分用积分和来近似，于是原微分方程和定解条件就近似地代之以代数方程组，即有限差分方程组，解此方程组就可以得到原问题在离散点上的近似解。

At present,the research of digital watermarking focused on discrete fourier transform domain, Discrete cosine transform domain, Discrete wavelet transform domain and others, but its robustness need to be improved.

目前，对于频域数字水印技术的研究主要集中于离散傅里叶变换域、离散余弦变换域和离散小波变换域等，但其鲁棒性能都有待提高。

The first, look like each detail picture of direction of picture and each layers to carry on DCT towards get of again, then will imbed to look like the son diagram DCT transformation through two value watermark pictures of the false random row preface behind of the part of the high part of frequency and the detail son diagram energy concentration.

本论文中提出的第一种算法是一种基于离散余弦变换和离散小波变换相结合的脆弱水印方法，即：先对图像进行离散小波变换，再对得到的近似图像和各层各方向的细节图像进行离散余弦变换，然后将经过伪随机排序的二值水印图像嵌入到近似子图DCT变换后的高频部分和细节子图能量集中的部分。

The stability and convergence of the fully discrete solutions are proved and the convergence order is also given.

从数值实验上也验证了该算法的可行性和高效性，对非定常N-S方程提出了一种新的全离散TGM：空间离散用标准FEM，时间离散用Crank-Nicolson格式，证明了全离散解的稳定性与收敛性。给出了收敛阶。

The Discrete Logarithm Problem was analyzed. Based on the discrete logarithm in the prime field, and combined with the elliptic curve DLP in the limited domain, a new digital signature was brought up.

分析了离散对数问题，以素数域上的离散对数为基础，同时结合有限域上的椭圆曲线离散对数问题，提出一种新的数字签名方案，其安全性建立在离散对数算法上。

This course includes (1) Discrete time signal and systems,(2) Z transform,(3) Continuous-time signal sampling,(4) LTI system,(5) Discrete time systems,(6) Filter design,(7) DFT,(8) FFT.

课程内容包含：(1)离散时间信号和系统，(2) z转换，(3)连续时间信号的取样，(4)线性非时变系统的转换分析，(5)离散时间系统的结构，(6)滤波器设计技巧，(7)离散傅氏转换，(8)使用离散傅氏转换以对信号做傅氏分析。

Mass of methods of the discretization have not think over relativity between before discretization and discretizated.The discretization of attributes are accomplished independence.It can change indiscernibility relation in information system and induce illogicality and redundance dot.

针对大多数的离散化方法没有考虑不同连续属性离散化结果间的互补性和相关性，每个属性的离散化过程都是独立进行的，往往会改变信息系统不可分辩关系，容易产生不合理和冗余的离散化划分点。

It effectively solves the problem of contact mechanics between burden granules. The dynamic data structure that is a linked list is built to save and delete the varying data in simulation calculation process. Therefore, the distinct element method simulation model of charging bell-less top blast furnace is established in view of the distinct element method model of blast furnace burden granular.

本文首先对离散单元法的基本原理和数值计算方法进行了系统研究，针对高炉炉料颗粒介质特点，对离散单元法进行了相应改进，建立了高炉炉料颗粒运动的离散单元法基本数学模型，推导出了相应的高炉炉料颗粒离散单元法数值计算基本参数的计算公式，例如阻尼、刚度、时步等，并确定了合理的数值模拟参数值。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。