查询词典 attenuation

Considering the 45-days' zero-flow of the river, the pumpage attenuation of seepage wells was calculated.

在考虑河流持续断流45d的情况下，计算了断流条件下渗流井出水量的衰减过程，在此基础上，确定了悖牛川陕西段河谷区地下水渗流井开采方式新增允许开采量。

Ricker wavelet: A particular seismic waveform which results from the transmission of a seismic impulse through an ideal viscoelastic material with attenuation proportional to the square of the frequency.

雷克子波：一种特殊的地震波形，它是由一地震波脉冲通过一理想粘弹性介质按频率的二次方衰减后得到的。

The issues of present seismic wavelet frequency caused by different concepts, such as apparent frequency, dominant frequency, peak frequency and centroid frequency, etc., which are defined by different methods, and understanding deviation, definition of seismic wavelet frequency for time and frequency domain are concluded and summarized. On this basis, three kinds of seismic wavelets in common use such as Ricker and Zinc wavelets as well as sine wavelet with exponential attenuation characteristics are analyzed and a conclude is achieved that apparent frequency and dominant frequency are consistent in essence, but peak frequency and centroid frequency as well as apparent frequency or dominant frequency are not completely consistent with different seismic wavelets. For actual seismic data, peak frequency can approximately be used as dominant frequency, but it is not suitable when seismic wavelet is known for it can give out any wrong knowledge and results.

针对目前地震子波频率由于定义方式出现的各种概念（视频率、主频、峰值频率、中心频率等）以及理解上出现的偏差等问题，首先从时间域定义和频率域定义2个方面进行了归纳和总结，并在此基础上对3种常用地震子波（Ricker子波，Zinc子波，正弦指数衰减子波）进行了分析和研究，得出视频率与主频概念一致，但不同地震子波的峰值频率、中心频率和视频率之间并不完全一致的结论；而对于实际地震资料，将峰值频率近似看作地震子波的主频是可以的，但在地震子波已知的情形下这样做是不恰当的，甚至可能会得出错误的结论和认识。

The findings: with the apparent dominant frequency of the Ricker wavelet rising, the detection SNR will get worse gradually, it is obvious that the variety of the SNR is slower during the portion of high frequency than during the portion of low frequency; in the usual range of seismic prospecting frequency, the SNR of the chaotic oscillator detection system could partially make up the amplitude attenuation aroused by the transmit of the seismic wave; the results could provide help for detecting the event constituted by aberrant wavelets.

本文以Ricker子波模拟地震子波，研究Ricker子波视主频变化的相应检测效果。研究结果：随着Ricker子波视主频的升高，检测SNR逐渐变差，在高频部分SNR的变化明显比低频部分缓慢；在通常地震勘探频率范围内，混沌振子系统检测SNR有可能部分补偿由于地震波传播引起的幅度降低；为检测由畸变子波构成的同相轴提供一定的可能。

These results suggest that evodiamine has greater anti-proliferative effects than rutaecarpine and possesses a potential for suppressing the proliferation of breast cancer cells via a mechanism involving attenuation of ERαand ERβ, interference of ERα phosphorylation and activation of apoptotic modulators.

故吴茱萸碱透过抑制α雌激素受体和β雌激素受体的表现、干扰α雌激素受体的磷酸化以及活化细胞凋亡调控因子来抑制乳癌细胞的增生。

The exploration of attenuation in the earth from seism observation station always is a defiant question for discussion.

利用地表波测量地球中的衰减一直是一个前沿性的挑战课题。

The variation regularity of the sheat strength index changing with the times of wet-drying cycling under upper loads was gotten in the test, it was also found that the upper load have the obvious restraining to the swelling-shrinkage deformation and the attenuation of shear strength.

得到有荷条件下膨胀土抗剪强度随着干湿循环的变化规律，并发现荷载对土的胀缩幅度和强度衰减有明显抑制作用。

The sinapate esters have greater UV-B attenuation and antioxidant activity than flavonoids.

拟南芥苗中还含有高浓度的黄酮和较高比例的五羟黄酮及4，5，7-三羟基黄酮衍生物。

In 2007, we performed 804 SPET/CT services in many aspects. Integrating CT was used for CT attenuation correction or morphological image fusion.

统计2007年当年共计进行SPET/CT造影804例，主要应用CT在辅助进行衰减校正或病灶定位。

Results: In 2007, we provided 602 SPET/CT services in myocardial perfusion scan for attenuation correction and 202 SPET/CT services in other scans for image fusion. Among 64 regional bone SPET/CT services, we noted 2 (3.13%) significant motion artifacts and 2 (3.13%) streak artifacts induced by beam hardening effect while among 25 Ga-67 local SPET/CT services. According to the features including low tube currents and slow rotating speed of this SPET/CT, some problems such as the patient safety, longer scan time, alignment mismatch and radiation protection would be analyzed and discussed.

结果：2007年804例SPET/CT造影中，602例心肌血流灌注断层摄影进行衰减校正，共202例病例进行影像融合，其中鎝－99m-MDP局部SPET/CT发生「影像上明显可见的移动假影」的比例为3.13%(2/64)，镓－67局部SPET/CT发生移动假影的比钊则为24%(6/25)，因射束硬化效应所造成的条状假影有产生干扰融合影像判读的情形，其他问题包括SPET/CT之CT低管球电压及低转速之机器特性、受检者的安全、较长的造影时间、对位错误及辐射防护筝。

So it was last week in Selma , alabama.

上星期在亚拉巴马州塞尔马市发生的事件也是这样一个转折点。

The group also spearheads various social programs in China.

该组织还带头参与中国的各种社会活动。