频率

However, please be noted that high sensitivity will allow the interfusion with exterior noise irrelevant to the quantity to be measured, which will be also amplified by the system.

传感器的频率响应高，可测的信号频率范围就宽，而由于受到结构特性的影响，机械系统的惯性较大，因有频率低的传感器可测信号的频率较低。

Based on a brief review of previous research, a judging criterion related the minimum frequency density parameter and the required modedamping ratio were proposed, which has a clear physical meaning.

在综述了已有研究的基础上，提出了新的密集频率判别标准，兼顾了密集频率组内外的频率间隔，采用的密集频率判别指标具有明确的物理意义。

In the 65 recorded neurons, the results showed: Characteristic frequency , minimum threshold and response latency was between 18.9 and 76.7 kHz (42.94 ± 11.29), 29 and 80dB SPL (58.65 ± 12.62), 3.1 and 13.4 ms (6.10 ± 1.47), respectively; CFs increased with the recording depth, but CF and MT were not correlated; There were three different types of discharge patterns in the IC, including phasic pattern (73.9%), chopper (15.4%) and tonic (10.7%); The types of frequency tuning curves were all V-shaped, most of which were wide type and few were narrow type.

结果发现，在所得的65个下丘神经元中：特征频率在18.9～76.7kHz(42.94±11.29)之间，最小阈值在29～80dB SPL(58.65±12.62)之间，潜伏期在3.1～10.4ms(6.10±1.47)之间；特征频率随记录深度的增加而增大，与最小阈值之间没有显著相关性；发放类型包括相位型(73.9%)、梳齿型(15.4%)和紧张型(10.7%)3种基本类型；频率调谐曲线均为开峰型，多数神经元(72.3%)调谐曲线较宽阔，少数(27.7%)较狭窄，并且多数神经元的频率调谐曲线高频边比低频边陡。

No additional data for frequency tracking are need, but higher estimation accuracy and low computational complexity can be obtained. Finally, a kind of optimizing joint algorithm for symbol timing, frequency synchronization and channel estimation is proposed. The false alarm probability and miss detect probability of the symbol timing are derived. We proved that the time－frequency offset domain random sequence sliding in the frequency offset direction is orthogonal with the original random sequence, and proposed a new integer frequency offset estimation algorithm. The coarse estimation methods for fractional frequency offset both in AWGN and multipath channels are proposed too.

最后，提出了一种优化的符号同步、频偏估计和信道估计的联合算法，推导了符号同步方法的虚警概率和漏检概率，给出了随机序列在时间－频率偏移域沿频率偏移方向滑动后与原序列近似正交的证明，提出了一种新的在时间－频率偏移域沿频率偏移方向进行滑动相关估计整数频偏的方法，提出了在AWGN信道和多径信道下进行小数频偏粗估计的方法，给出了小数频偏细估计的ML估计结果和利用频域PN序列取值特性的简洁的信道估计结果。

Broadcast can completely be reborn in narrow broadcast. The strategy of the narrow broadcast is how to realize the specialization of frequency. The specialization of frequency in our country has not been well developed. The specialization of frequency, in the term of audience, is the particularization of audience.

广播的"窄播"策略，实质上就是一个如何实现频率专业化的问题；我国广播的频率专业化还很不充分，频率专业化，从受众的角度来讲，就是受众细分化；广播可以从受众群体、受众需求、接受时间等维度来细分受众，在专业频率中凸现贴近性、服务性和参与性。

It was found that the pemeability of the dust core was almost a constant in the frequency range from 1KHz to 100KHz,and the quality factor Q of dust core increased with increasing frequency.It was also found that Q became higher at the frequency over 50KHz in comparison with that of permalloy in higher frequency.

结果表明，在测量的频率范围内(1KHz-100KHz)，该粉芯的磁导率几乎不随频率变化而变化；粉芯的品质因数Q随频率的增加而增加，在较高频率时有着比坡莫合金粉芯还要高的值，具有应用价值。

And various limiting factors are analyzed. It is found that the stability is mostly limited by the noise of photodetector and frequency modulation in the experiment. Several methods of improved stability are also presented here.

从理论上定性分析了频率稳定度受到的各种限制因素，最后得出本实验中频率稳定度主要受频率调制和探测器噪声限制的结论，同时给出了提高频率稳定度的方法。

Processors analyze and monitor seismic frequencies in order to select proper time and frequency parameters in data processing.

在地震勘探过程中，多种因素影响地震波频率的变化，在数据处理过程中分析和监控各种波场的频率属性能够使处理人员了解数据频率成分的变化规律，有针对性地选择处理中的空变参数和频变参数。F-X-Y谱估计方法在三维空间上统计有效波的频率，结果较准确，对问题的分析更加细致。

In the work, employing a function with four undetermined parameters to model the source wavelet, an analytical relation between Q-factor and envelope peak instantaneous frequency is derived from the theory of one-way waves propagating in an anelastic medium; at the same time, a method for extracting instantaneous frequency in wavelet domain is developed for improving the precision and anti-noise performance of IF estimation, and based on these, a method called EPIF in wavelet domain is proposed for estimating Q-factor of VSP data.

本文采用一个具有4个待定参数的函数去逼近震源子波，利用黏弹介质中单程波传播理论推导出了地震子波包络峰值处瞬时频率和品质因子之间的解析关系；同时，为提高瞬时频率的估计精度和抗噪性能，在小波域中发展了一种计算瞬时频率的方法，并在此基础上提出了估算VSP资料Q值的方法，简称小波域包络峰值处瞬时频率法。

And the average WDI for every month was calculated from 60 decades WDI and the drought frequency for every month was obtained with a drought criterion. Results showed that: in spring, North-western China, Northern China and Southern China have a higher drought frequency; in May to August, the region that has a higher drought frequency focus on North-western China and Northern China; from September to December, North-western China, Northern China, center China and Sichuan basin has a higher drought frequency (6) The relationship between average WDI for all the 720 decades in 20 years and average precipitation was analysed and was used to regionalize drought in China.

5分析我国近20年干旱发生的时空分布特征：利用1982-2001年NOAAAVHRR8km数据集，计算了20年来我国各旬干旱空间分布，并根据一定的干旱发生判断标准，统计我国不同地区在各月相发生干旱的频率和各月份平均WDI，初步分析我国干旱发生的时空格局，结果表明：在春季，西北地区、华北平原和华南大部分地区的干旱发生频率都比较高；在5-8月份，高频率干旱发生地区就主要集中在西北和华北平原地区；9-12月份干旱发生高频率地区在主要在西北、华北、华中和四川盆地等地。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。