查询词典 Doppler range

The opened magnetic circuit is composed as tow NdFeB permanent magnets and a top plate without U-yoke. After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

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。

The study indicates that the influence of Doppler effect on pseudo-range observations is proportional to the product of pseudo range and the rate of pseudo-range variation.

研究表明，多普勒效应对伪距观测值的影响与伪距和伪距变化率的积成正比。

Because the scatterers at different range cells may have different Doppler characteristics, the range migration correction for moving ship is completed by coarse and fine correction procedures. The compensations of second and higher order phase terms are implemented in "range frequency - azimuth time" domain.

根据船体上不同距离单元散射点多普勒历程可能不同的特点，采用粗校正和精校正相结合的方法在距离频率-方位时间域进行二阶和高阶相位补偿，完成运动舰船目标的距离徙动校正。

COV gathers can also be constructed through selecting traces from different cross spreads of a 3D survey. A simple and practical way of constructing COV gathers can he described as that 1 when a dominant receiver line direction is determined, the inline offset and crossline offset of every trace can be calculated; 2 the inline offset and crossline offset ranges fruit; negative to positive for the whole dataset can be well represented by the range of the receiver spread of a typical source; 3 the full range of inline offsets can be divided into several sob ranges using twice the source line spacing and the full range of crossline offsets can be divided using twice the receiver line spacing; and 4 one sod; sob-range inline offset and one such sob-range crossline offsets form a COV gather.

一个简便实用的构造COV道集的方法是：在给定检波线的走向后，计算出每一地震道的inline炮检距和crossline炮检距；用观测系统中一个具有代表性的炮点的检波器排列范围来确定整个数据的inline炮检距范围和crossline炮检距范围，用两倍的炮线间距把inline炮检距的范围分成若干份，用两倍的检波线间距将crossline炮检距的范围也分成若干份，一份inline炮检距和一份crossline炮检距就构成一个炮检距向量道集。

Sensitive range from 49.1% to 100%, specificity range from 18.2% to 90%,accurate range from 45.5% to 88.3%, PPV range from 34.1% to 95.2,NPV range from 22.2% to 100%,the combine sensitive was 82.7%,specificity was 63.3%;there were not obvious publish bias in the 9 articles, and there was heterology of the 9 articles, the forest figure show RR was 2.34[1.43,3.05],and its 95% confidence interval did not include 1,the chance of malignancy nodules'SUV above 2.5 were more than benign nodules.

文献报道的敏感性49.1-100%，特异性18.2-90.0%，准确性45.5-88.3%，阳性预测值34.1-95.2%，阴性预测值22.2-100%，Meta分析合并后的敏感性82.7%，特异性为63.3%，准确性为71.8%，阳性预测值80.8%，阴性预测值57.0%；漏斗图成近似倒三角形，认为文献无明显发表偏移；对文献异质性检验，P小于0.05，认为文献来源存在异质性；选用随机效应模式得到森林图，RR为2.34[1.43，3.05]，其95%的可信区间不包括1，认为肿瘤病人最大SUV 2.5法呈阳性的可能性大于非肿瘤病人，二者之间具有统计学差异；两篇来源于日本的文献显示日本国的18F-FDG PET肺占位显像假阴性率高于我国。

After that, a numerical model about Zhejiang shore tide is established by mike21 program. After validating the good agreement between simulated results and observed ones, the planar hydrodynamic flow of this ocean area is analysed in detail. Then co-tidal and co-range chart of each main tide is drew based on the computational result. It can be found that each co-tidal and co-range chart that is based on the simulated result is suitable to the co-tidal and co-range chart that is deduced from autoptical data, besides, the modle co-tidal and co-range chart can perfect the co-tidal and co-range chart from autoptical data where autoptical data is too hard to get .

在这之后，使用MIKE21水动力模块建立起浙江近海海域潮波模型，在模型潮位、潮流流速流向验证均合理的基础上，分析了计算得到的二维水动力流场，最后将模拟结果绘制出浙江近海M2、S2、N2、K1、O1主要分潮的同潮时图，并将其与实测同潮时图比较，发现各分潮等振幅线及同潮时线相同或相近值的等值线位置及走势基本一致，而且模拟得到的同潮时图对实测资料覆盖不到的海区做了适当补充。

In degraded PSM matching classification, errors modification method of degraded PSM is presented and the matching tensor of every canonical scattering centers is given. In Chapter 4, the theory of wideband millimeter-wave radar target identification is introduced. It is indicated that, for HR radar target identification, description of temoral relations among features and pattern recogntion adaptive to variation of target angles are of key importance. A rule-based pattern recogniton method of sequential reasoning is proposed, which uses a series of rules to describe relations of features variation caused by target angles variation and has the advantages of adaption to unrandom variation and false probability control in classification over traditional statistical pattern recognitiop method. Feature extraction is crucial step in target identification. In range profiles identification application, features are extracted by means of range domain pre-processing algorithm, spacial and amplitude visual computation directly from range profiles and transform algorithm based on range profiles. Visual or transformed features are either sufficiently convinced or necessarily convinced and both of them are effective and robust to range profiles identification.

在第四章，首先对宽带毫米波体制背景下目标识别方法的一些特点进行了阐述并指出，在毫米波雷达目标识别中，特征之间动态关系的描述以及能适应目标姿态角变化的模式识别方法的研究乃是要解决的关键问题；进而提出了一种基于规则库的序贯推理模式识别新方法，在这种方法的研究中，主要包括序贯推理规则库的规则排列与特征选用顺序以及规则库的收敛等问题；这种方法克服了传统的统计模式识别方法特征利用效率不高、难以适应特征值的非随机性变化的缺点，把姿态角变化所引起的特征的变化用一系列规则加以表示，其优点是能适应特征值的非随机性动态变化，并能控制分类过程中的差错概率α；特征抽取是目标识别中的关键步骤，在基于目标距离像的特征抽取方法研究中，提出了距离空间域的预处理算法、距离空间域与幅度域的直观特征抽取方法以及基于目标距离像变换分析的特征抽取方法。

Laser Doppler anemometer is used to measure the speed of wind in the atmosphere based on the theory of Doppler technology.

激光多普勒测风雷达是利用激光多普勒效应测量大气风场速度的一种技术。

Finally discussed the conception of the connatural time and observation time, and take example for atomic clock and pulse laser Doppler speedometer, particular analysed problem of antipathic between 'formula of time slow' and formula of Doppler of light, and try to explained some dark understand about this problem before .

最后从固有时间和观测时间的概念入手，以铯原子钟和激光脉冲多普勒测速仪为例，详细分析了"时慢公式"与光多普勒定律之间的不相容问题，并尝试解释了以前对此问题的一些模糊认识。

Article 144 The Government of the Hong Kong Special Administrative Region shall maintain the policy previously practised in Hong Kong in respect of subventions for non-governmental organizations in fields such as education, medicine and health, culture, art, recreation, sports, social welfare and social

第一百四十四条香港特别行政区政府保持原在香港实行的对教育、医疗卫生、文化、艺术、康乐、体育、社会福利、社会工作等方面的民间团体机构的资助政策。原在香港各资助机构任职的人员均可根据原有制度继续受聘。

Small wonder, then, that the Chinese spend more in the shop than any other group of foreign visitors do .

这样的小惊喜，使中国顾客比任何国家的人消费得更多。