查询词典 echo chamber

The software of data editing and post-processing is a crucial tool for every institute executing echo-sounding jobs. The echo-sounding group of Institute of Oceanography National Taiwan University had developed a program named "Depth" since 1994 and using it to accomplish many echo-sounding works on

水深资料编修软体为各测深工作单位不可或缺的重要工具，国立台湾大学海洋研究所於1994年即自行开发Depth编修软体，近10年来已应用於海域及水库测深计画并取得良好成效。

In the precision detection of a millimeter wave, the encounter of the detector and the objects can not be forecasted totally because of a lot of noise and disturbance existing in the complex battlefield, it will cause fantasticality and distortion of the echo retaked by the detector, and the stably of the echo become bad, as a result, it will reflect the result of the detection, so it is necessary to filter the echo retaked by detector.

在弹载毫米波精确探测系统中，由于复杂多变的战场环境中存在大量的干扰及噪声，探测器与目标的交会姿态不能完全预测，造成探测器获取目标回波产生奇异和变形，回波特征的稳定性变差，从而影响了目标的探测和识别，因此对探测器的回波进行有效的滤波处理是十分必要的。

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。

The indirect sign included the stercolith in the appendix with sound shadow; periappendicular absence echo or deposit echo when appendicitis complicated with exudation or perforation; mixed swollen echo on the right hypogastric region when abscess formed; dilation of intestine; local ileocecal edema or mesenteric thickening and encysted greater omentum.

横断面呈&靶环征&或圆形回声。2 间接征象：阑尾内粪石并声影；阑尾炎有渗出或穿孔时周围的无回声区或有沉积物回声；脓肿形成时为右下腹混合性肿块回声；肠管扩张；回盲部肠管局限性水肿或肠系膜增厚和大网膜包裹。

The indirect sign includes the stercolith in the appendix with sound shadow; periappendicular absence echo or deposit echo when appendicitis complicated with exudation or perforation; mixed swollen echo on the right hypogastric region when abscess formated; dilation of intestine; local ileocecal edema or mesenteric thickening and encysted greater omentum.

间接征象：阑尾内粪石并声影；阑尾炎有渗出或穿孔时周围的无回声区或有沉积物回声；脓肿形成时为右下腹混合性肿块回声；肠管扩张；回盲部肠管局限性水肿或肠系膜增厚和大网膜包裹。B超检查简便、可重复性对阑尾炎诊断有很大的实用价值，应列为首选的影像检查方法。

The motion dynamics and echo models of the precessing warhead in single frequency are set up. Based on a quantitative analysis on echo spectrum and micro-Doppler modulation of precessing cone, a precession parameter estimation method by echo correlation and spectrum width is proposed. The experiments on data by simulation and darkroom measurement verify the method.

建立了单频信号下雷达观测弹头的进动模型和回波模型，通过对进动弹头回波频谱与微多普勒调制特性的定量分析，提出了利用回波相关方法和频谱展宽估计进动参数的方法，并利用暗室测量数据对该方法的性能进行了实验验证。

Careful analysis on NBE can facilitate nowcasting of severe weather events and further understanding of their evolution. After detailed study on three cases concerning with NBE, it is concluded:(1) NBE triggered by fast moving echo in upstream is an important indication of disastrous wind;(2) NBE can develop into severe storm under proper conditions. There are often two stages during this kind of growing: the first is developing of initial echo, the second is snap growing of echo core;(3) Doppler radar reflects outflow of downburst as a nearly ringed NBE. Inside look on downburst can be obtained combining NBE with other data.

文章结合发生在上海的3次强对流天气个例，详细分析了弱窄带回波在分析和预报强对流天气中的作用，得出以下结论：（1）上游移动强回波的出流边界导致的弱窄带回波是大风预警的重要判断参考；（2）在合适的层结状态和抬升条件下，弱窄带回波会强烈发展，并导致局地雷雨大风，这类强对流天气的发展有两个比较重要的阶段：弱窄带回波上初始回波的发展和回波跃增；（3）下击暴流造成的地面出流在雷达回波上表现为近似圆弧的弱窄带回波，这种弱窄带回波与其他雷达观测特征以及地面观测相结合，有助于对产生下击暴流的对流云的发生发展过程进行细致分析。

This method first jitters chirp rate polarity of LFM signal transmitted by the radar in slow-time domain,then does match-filters for the jamming signals hidden in the radar echoes,since jamming is more powerful than radar echo,the next process of limiting will lower the amplitude of jamming greatly,after limiting process,limited echoes are inversely match-filtered,so jamming and real radar echo are all back to the original time domain,then the next normal imaging process can be implemented which will also provide the real radar echo more gain than jamming,so SJR(Signal-to-Jamming Ratio) is further enhanced.

该方法首先在慢时间域捷变雷达发射信号的调频斜率极性，其次在接收脉冲后首先对转发的干扰信号进行匹配、限幅，然后在逆滤波之后正常成像。

Improved echo canceller for double-talk detection ;2. It is pointed out that the false detection results in the echo cancellation system to be unstable when traditional double-talk detection methods are applied in the echo cancellation.

首先讨论了回声消除中的双端发声问题，指出传统的双端发声检测方法用于回声消除时，其不可避免的误检会导致回声消除系统性能严重恶化，使系统不稳定。

An opening and at least one ventilation hole are provided in opposite sides of the partition wall, respectively, so that a part of air and dust vortically moving in the cyclonic air flow chamber are introduced into the dust collection chamber through the opening and the air in the dust collection chamber flows back into the cyclonic air flow chamber through the ventilation hole.

在该隔离壁的相对的侧面提供开口和至少一个通风孔，使得在该旋风气流室中旋涡状地运动的一部分空气和灰尘通过该开口被引入集尘室中，并且集尘室中的空气通过该通风孔回流到旋风气流室中。

World War II: Battle of Saipan - Americans take Saipan.

1944年的今天，美国在塞班战役中拿下塞班岛。

When the scorner, the rejecter of truth, has become presumptuous; when the routine of work in the various money-making lines is carried on without regard to principle; when the student is eagerly seeking knowledge of everything but his Bible, Christ comes as a thief.{DA 635.3

当讥诮和拒绝真理的人，到了任意妄为时，当追求财利者罔顾按道义经营谋利时，当学人正在兢兢业业地研究各种知识，而单把圣经丢在一边时，基督要像贼一样来临。