查询词典 band

A series of ka-band propagation experiments supported by ETS-II ,Olympus, ITALSAT. ACTS . Techniques such as rain fade mitigation, spot beam and shape beam have been developed . the commercial apply of ka-band satelliate will be soon.

Ka波段的试验卫星如ETS-Ⅱ、Olympus、ITALSAT、ACTS等已经证实了ka波段卫星通信的可能性，所采用的信道编码、点波束、数据速率调整等抗雨衰关键技术都已成熟，估计第一颗商用通信卫星将会在数年内投入使用。

A mixed sensitivity H∞ control model is constructed and the band width of wind turbine speed control is designed according to the frequency characteristic of wind speed variation and noise of rotating speed sensor. The sensitivity function is decreased within this frequency band to restrain the wind torque perturbation to wind turbine rotating speed control.

通过构造基于复合灵敏度的H∞鲁棒控制模型，根据风速的波动频率范围和传感器的噪声频率范围设计了风车转速控制的带宽，并在此带宽内降低系统的灵敏度函数，来抑制风力转矩对风车转速控制的干扰。

In my city peripheral 200 kilometers scopes has the nearly ten state-levels key sceneries scenic spot area, is Jiangsu Zhejiang and Shanghai the traveling source of tourists market and the Jianxi Fujian Anhui traveling resources gathers the place the gold point, is the coastal plain wind band of light the gradient corridor which extends to the interior scenery wind band of light, also is eastern part the developed area leads to the mid-west to owe developed local the stopover station; Day by day appears transportation superiority.

我市周边200公里范围内有近十个国家级重点风景名胜区，是苏浙沪旅游客源市场与赣闽皖旅游资源集聚地的黄金结点，是沿海平原风光带向内陆山水风光带延伸的梯度走廊，也是东部发达地区通往中西部欠发达地区的中转站；日益显现的交通优势。

To solve the exsisting problems in the realization of the LFM/CW radar, the thesis presents a technique for dynamically measuring the LFM/CW signals, which can accomplish the dynamic measurements of FM linearity, FM bandwidth and FM slop of the transmitted signals of LFM/CW radars. This technique creates an effective and accurate means of judging the performance of LFMCW radars. The linearity-correction techniques presented in the thesis successfully make the linearity of the transmitted signals of an actual LFM/CW radar reduce from approximately 25% to 0. 1%(or r. m. s linearity of 0.04%), better than the best results (0.22%) obtained by foreign researchers with complex linearization closed-loop in the same kind of LFM/CW radars, according to the published literatures during the last decade. In order to improve the capability of the real-time processing and range-cells management of LFM/CW radars, the principle of equivalent mixing by lacking-sampling process of band-pass real signals is proposed based on the well-proved improvedversion of sampling theorem of band-pass real signals. This principle is used to configure the range-segments processing of the beat signals of an actual LFM/CW radar. The techniques of system-background interference suppression and the beat signal's dynamic range suppression are proposed, and are realized in an actual LFM/CW radar to demonstrate their effectiveness.

针对线性调频连续波雷达实现中急待解决的技术问题，文中提出并验证了线性调频连续波信号的综合动态测试技术，可以完成对线性调频连续波雷达发射信号的扫频线性度、扫频带宽和扫频斜率的综合动态测试，为衡量实际线性调频连续波雷达的系统性能创立了精确有效的测试手段；文中建立的非实时闭环动态校正技术使一部实际的线性调频连续波雷达的发射信号（时带积3×10〓）的扫频线性度从25%改善为0.1%（方均根线性度0.04%），优于国外已公布的80年代同类雷达中采用复杂的实时闭环动态校正环路所获得的实际结果（0.22%）；为了改善线性调频连续波雷达的实时性和分辨单元数处理能力，文中发展完善了实带通信号的采样定理并给予了严格证明，并在此基础上提出了欠采样等效混频原理，将其应用于实际线性调频连续波雷达的距离分段处理中；针对线性调频连续波雷达中系统背景干扰和回波动态范围问题，创立了系统背景综合抑制技术和频域动态范围压缩技术，并将它应用于实孔线性调频连续波雷达系统中，显示出它们的有效性。

The experiment also shows that it is possible to get oil spill imaging from near ultra-violet to red spectral region with optimal spectral band selecting, but the violet-blue region is a best band, then blue-green, and the red region is poor for oil spill imaging.

实验还表明，选择最佳光谱段组合，从光谱近紫外区到红区均能获取海面油溢图像，其中以紫蓝光谱区最为理想，近紫外区和蓝绿光谱区次之，红区较差。

A new formula for the valence band effective states is obtained,and the effect of the conduction band effective states on the built-in electric field is considered for the first time.

重新拟合了价带有效态密度公式，并在计算内建电场时考虑了导带有效态密度的影响。

The simulations of two models are close to canopy albedo observation in this band. This indicates that the two-stream model can simulate the canopy albedo very well and the improvement of four-stream model is limited. The results also show that the albedo of the canopy modeled by the four-stream model is greatly improved than that of the two-stream model in the NIR band.

这表明在可见光波段，二流模式已经能够较好模拟冠层反照率，四流模式能够提高的精度范围有限；在近红外波段，因叶片散射率值较大，两个模式模拟结果差别较明显，四流模式模拟的冠层反照率相对二流模式的模拟结果更接近观测值。

According to the mine shaft tunnel to the microwave frequency band in the certain degree to the channel characteristic, the radio frequency selects the microwave frequency band 433MHz to make the carrier, enables the wireless signal to carry on the effective dissemination in the line of sight distance, has the transmission stability to be good, external interference small merit.

根据井下隧道对微波频段在一定程度上相当于通道的特点，射频选用微波频段的433MHz做载波，使无线信号能够在视线距离内的进行有效传播，具有传输稳定性好，受外界干扰小的优点。

The main properties of one-dimensional photonic band gap structures that include layers of negative refraction material are analyzed from the explicit dispersion equation. The results show that the photonic crystals containing negative refraction materials have wider photonic band gaps which is different from the case of traditional photonic crystals with narrow transmission bands when the two layers have the same optical thickness.

从色散关系出发，通过数值模拟计算研究了由正折射率材料和负折射率材料交替组成的一维光子晶体的能带结构与光子晶体的结构参数之间的关系。

Once, on a train, the conductor asked me if I had passed the Band Six exam. When I explained to him that in the US students don't take the band examinations, he asked me what my TOEFL score was. I said that English was my first language, so there was no need for me to take the TOEFL.

有一次我坐火车，列车员问我是否通过了大学英语六级考试，当我解释美国学生不参加这种等级考试时，他又问我的托福分数是多少，我说英语是我的第一语言，我不必参加托福考试。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。