数目

However, it never reached critical mass and there are no known applications or implementations.

然而，它数目从来没有达到一定的临界点，并且也没有一个知名的应用和应用软件。

In other words, the underground Christian house church movement is about to reach critical mass.

译：用另外的话说，地下教会运动将会达到一个关键性的数目。

Chaotic sequence has the advantages of massive, high security, and good performanceof auto correlation and cross correlation.

混沌序列具有对初值的敏感性，良好的自相关性和互相关性，不同码元的数目平衡。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

Being light and produced in large numbers, pollen grains can be more easily reaching the stigma of another flower so as to achieve cross-fertilization.

花粉粒，因轻而数目够大量，它能够容易到达另一株植物的柱头，以达至异花传粉的目的。

Let the distance between two cross-roads be equal to the number of street segments which one has to go from the first cross-road to the second.

我们定义两个交叉路口之间的距离等于某人从一个交叉路口走到另一个交叉路口所必须经过的街道段的数目。

Crusted scabies is extremely contagious, because of the larger number of mites, and can be passed on through bedding, towels, clothes and upholstery, as well as close physical contact.

地壳疥疮是非常的传染性，由于规模较大的数目，螨类，并可以通过就通过床上用品，毛巾，衣服和装饰，以及密切的身体接触。

Our results reveal that with the same number of cobalt atoms and the same cobalt-substrate interation stength, the melting points and pre-melting intervals of the two kinds of supported Co clusters are all in reasonable agreement with each other. With increasing the depth of supported potential, the melting points increase for the supported cluster. Similar to the case of free clusters, the linear relation between the melting point and the inverse of cluster's size cube root is also found for the two kinds of supported clusters.

结果表明：对于给定原子数目的支撑Co团簇，在衬底势强度相同时，两种衬底势下对支撑团簇熔点及预熔化区间给出了一致的描述；随衬底势强度增加，支撑团簇熔点升高，且两种衬底势所描述的支撑Co团簇也类同于自由Co团簇都表现出较好的熔点与尺寸依赖的线性关系。

A method of the source number estimation is proposed based on the fourth order cumulant information.

提出了一种基于阵列输出4阶累积量信息的信源数目估计方法。

For the multifractal method, there is still no standard being set up to determine the threshold anomaly of metallogenic prognosis by the soil elements. This paper presents a calculation method using the cumulative frequency of elemental contentsnumber of deposits. The anomaly area obtained by this method can well identify the most of known deposits. Meanwhile, by this method some blank abnormal areas which are worthwhile to do further anomaly inspection have been identified.

多维分形方法下土壤元素成矿预测的异常下限值确定尚无标准，文中采用元素含量矿床数目累积频率的计算方法，基于该方法提取的成矿异常区域较好地识别出了绝大多数已知矿床，同时识别出了值得作进一步异常查证的空白异常区域。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。