查询词典 Doppler shift

After studying the effect of Doppler broadening on the inversionless optical gain of a four-level system driven by a coherent field, the general results of the effect of Doppler broadening are given.

虽然无反转激光只需在上能级有少量的粒子数布居即可实现激光输出，但如何泵浦高激发态能级仍是实现短波长激光的主要障碍。

The new assembled digital Doppler rader was introduced in this paper. The results of comparison experiment show that the speed and direction of wind detected by the new rader conicide with those by tethersonde, and its functions are equivalent to those of Doppler acoustic radar with separated antenna developed previously in China and other countries.

本文对新设计的集合式数字多普勒声雷达作了介绍，对比试验结果说明新设计的声雷达测量风速和风向的结果与系留气艇测量结果相符很好，其性能与过去国内和国外分离式天线多普勒声雷达的性能相当。

Objective To comparative study of color doppler energy with color doppler flow imaging in diagnosis of small hepatic hemangioma.

目的为对比研究彩色多普勒能量图与彩色多普勒血流显像在诊断肝脏小血管瘤中的作用。

Acoustic Doppler Current Profilers is a new kind of flow measuring device widely used in hydrometry. It uses the principle of Acoustic Doppler instruments to measure flow velocity profile. A short time flow measurement, high resolution, good accuracy, integrity data and great information are the characters of ADCP.

多普勒测流仪是当前在水文行业推广的一种新型测流仪器，该仪器利用声学多普勒原理，测量水流速度剖面，具有测验时间短、分辨率高、精度好、资料完整、信息量大等优点。

Objective To evaluate the significance of color doppler flow imaging. Methods 30 cases of internal jugular vein dilation were examined by color doppler flow imaging.

目的 探讨彩色普勒血流显像在颈静脉扩张症诊断中的临床价值方法应用彩色多普勒血流显像对30例颈内静脉扩张症的患者进行检查。

In order to decrease the measuring error of signal processing in laser Doppler velocimeter, frequency spectrum correction methods for lacer Doppler signal were proposed. Basic principles of energy centrobaric correction, ratio correction and phase difference correction were expounded. The three methods processing ideal sinusoidal signals was simulated with different signal frequencies, and so was the ratio method processing sinusoidal signals with different noises and signal to noise ratios.

在激光多普勒测速仪中，为了减小由信号处理算法带来的测量误差，提出运用频谱校正算法对多普勒信号的频谱进行校正，详细阐述了能量重心法、比值法和相位差法3种离散频谱校正算法的基本原理，运用这3种算法对理想正弦信号进行仿真，并运用比值法对信号施加不同频率和信噪比的噪音下的正弦信号和实测的多普勒信号进行仿真及实验研究。

With this method,carrier Doppler was firstly estimated with Periodogram Spectral Analysis method;then LOS Doppler velocity was calculated;and finally,the velocity of the receiver was compu...

首先应用周期图法估计片段GPS信号的多普勒频移，计算视距变化率，然后建立视距变化率方程，进而求得接收机的速度。通过Matlab模拟的信号和GPS仿真器模拟产生的高动态信号仿真验证了多普勒频移的估计精度和用户速度的测量精度。

The key problems of software radio and direct sequence spread spectrum range used in high range radio fuze are discussed. The effects of doppler frequency and carrier's initial random phase are analyzed. A new direct sequence spread spectrum algorithm based on software radio is proposed, by using differential encoding and quadrature demodulating, the effects of doppler frequency and carrier's initial phase on the output of inference filter are eliminated successfully.

研究了软件无线电和直接扩频测距技术在大炸高无线电引信应用中的关键技术问题，分析了由于多普勒效应引起的载波频偏以及载波随机相位对测距的影响，提出了一种基于软件无线电的直接序列扩频解调算法，通过采用差分编码和正交解调的方法，消除了多普勒频偏和载波随机相位对测距的影响。

First, in order to verify the correct of this retrieval month, by using the data of three-dimensional wind field, raininess field and temperature field that are output by MM5 numerical simulation, we climate the radial velocity field and echo intention field in the in-phase observation area of Dual-Doppler radar, then, on the base of the upwards retrieval theory and using the radial velocity field and echo intention field in the in-phase observation area of Dual-Doppler radar, we retrieve the atmospheric three-dimensional wind field.

首先，为检验此种反演方法的可靠性，我们使用MM5数值模式输出的三维风场、雨强场、温度场等数据，分别模拟生成两部雷达同步观测区的径向速度场和回波强度场，然后根据以上的反演理论利用模拟的双多普勒天气雷达观测到的径向速度场和回波强度场反演出大气三维风场。

The main contents is: analyzing some detection method to moving target nowadays; particular studying the principle of detection moving target in SAR; analyzing SAR imaging theory and the echo model of moving target; discussing conventional SAR imaging , the movements of target cause the changes of doppler mass center and regulable frequency, and the changes cause effect the imaging result; introducing the estimation method of doppler parameter; analyzing theory of DPCA, derivating the formula needed, and validating it's validity and practicability through simulation; advancing the improved DPCA algorithm that combine the advantage of DPCA and ATI, and validating it through computer simulation; using the revision algorithm to range ambulate based on keystone transformation, and validating it through computer simulation; discussing the compensation art of SAR imaging.

主要内容有：分析了现有的一些动目标的检测方法；详细研究了SAR动目标检测的原理；分析了SAR成像理论和运动目标的回波模型；探讨常规SAR成像时，目标运动引起的多普勒质心和调频率变化，以及这些变化对成像结果的影响；介绍了多普勒参数的估计方法；分析了DPCA原理，推导所需要的基本公式，并仿真验证其有效性和实用性；提出了结合DPCA和ATI优点的改进DPCA算法，并仿真验证；探讨了SAR成像中的运动补偿技术。通过对仿真结果的分析，本文提出的方法具有一定的指导意义和参考价值。

There are different types of personal loans available.

有许多不同类型的个人贷款优惠。

The above mentioned teaching model of spiral rising can be used to avoid rigidness in teaching.

上述螺旋式上升的教学模式，可以避免教学形成模式後的僵化现象。