低频

The results show that the decalescence of catalyst bed affects the process of hydrogen peroxide catalytic decomposition greatly. If the catalyst bed is preheated or made up of materials with low thermal conductivity, that influence can be depressed. At the same time, the response characteristic of catalyst bed and the efficiency of catalytic decomposition can be improved. The low frequency pressure instability of catalyst bed occurs because of the coupling of catalytic decomposition and supplying. The decomposition plane pushes all the way through the catalyst bed during pressure oscillations, causing unreacted liquid hydrogen peroxide to be exhausted from the bed and leading to the appearance of liquid hydrogen peroxide channeling. Consequently, how to prevent or at least limit this channeling is the key to eliminate the pressure instability of catalyst bed. It was found that adding clapboard to the catalyst bed can depress the pressure instability efficiently.

结果表明催化剂床及催化剂的吸热对过氧化氢分解过程影响很大，对催化剂床进行预热或采用热导率低的材料制造催化剂床等措施，可以降低催化剂床壁面吸热对催化分解过程的影响，提高催化剂床的响应特性和催化分解效率；催化剂床的低频不稳定是催化分解过程与供应系统耦合产生的，催化剂床气体界面的波动过程中，液体过氧化氢穿透催化剂床形成过氧化氢液体通道，过氧化氢液体通道的产生和扩大是催化剂床不稳定的主要原因，也是消除催化剂床不稳定的关键，试验中在催化剂床内加入分流板成功地抑制了催化剂床的低频不稳定。

The neglect of edge diffraction is one of the most important reasons.

这种方法在低频情况下的精度较差，主要原因是忽略了在低频声场中起重要作用的波动现象。

This present algorithm further distinguishes itself through sufficiently utilizes the advantage that the vector sensors provide from other beam space DOA algorithms in several regards: 1 beams are formed in the vector-field domain; 2 produce at moderate signal-to-noise ratio estimation performance comparable to the traditional scale array methods;3 these vector-field beams are formed blindly using no apriori source information and coarse estimates of the direction cosine are derived to start off MUSICs iterative search so it demand less computation; 4 deploy agilely , since the fact that the output channel is various .

本文提出了矢量传感器阵列的自适应综合校准补偿方法，还提出利用单矢量传感器速度协方差矩阵分解来求解目标源方位，使得我们不要求校准源是合作性的，也无需知道校准源的先验知识，这比起常规辅助源校准方法具备较大宽容性。随着高性能阵列处理技术及数字信号处理硬件的快速发展和矢量传感器制造工艺的不断成熟，矢量传感器将在新型水雷、低频远程智能鱼雷、声纳浮标、低频拖曳线列阵和新型舰壳声纳，灵巧传感终端，战场监视系统，反隐形雷达，通讯等军民用领域取得良好的发展应用前景。

The 15 low frequency driver combines 96 dB sensitivity with 1000 Watts power handling, to deliver LF sound pressure levels well beyond those typical of systems its size.

在15低频驱动器结合96分贝1000瓦灵敏度功率处理能力，能够提供远远超过低频声压水平的典型系统的大小。

We started with a powerful 12", long-excursion low frequency driver for abundant bass punch and accurate low midrange. Next we joined a high-resolution 1" HF driver for clarity and brilliance with a groundbreaking horn design, ensuring smooth frequency response and ultra-wide sound dispersion so you can move around the stage.

这款产品配有功率强大的 12 英寸长冲程低频驱动器，提供铿锵有力的低音和精准的中低频；高解析度 1 英寸高频驱动器和设计新颖的号筒，提供明亮通透的高音，确保平滑的频率响应和极大的声音扩散角度，使你能在舞台上自由跑动。

There is a Zigzag channel in the earplug, which lets speaking tones pass and absorbes high frequency noise.

在低频噪声场合时，可用小塞封闭弯曲管道，耳塞又能有效地隔去低频有害噪声。

So the bass and some of the midrange of the signal flows in an electrolytic capacitor, period.

它不管低频，经常也不管中频，所以低频和中频的一部分是通过电解电容的。就是这样。

To help provide this level of realism, most reverb units allow you to adjust the reverberation time for high frequencies relative to middle frequencies, and introduce some kind of overall equalisation to the reverberation tail.

这里建议大家能在REVERB之前加入一个EQ，先对进入REVERB之前的声音做一次低频清洗运动，然后反复SOLO REVERB的声音，确定低频在经过REVERB后没有变得溷浊模糊。

In order to improve the reliability of the nuclear Generating Sets and the stabilization of the power system, prevent the long time low frequency oscillation caused by the disturbed of the outside electrical net, assured improving the stabilization margin of the nuclear generating sets in the precondition of enough transient stability, validate the sensitivity of the parameter to the damping of Generating Sets of the MEC5220 digital excitation adjustor produce in Japan that used in the Second Project of Qinshan Nuclear Power Plant, confirm the parameter rationality of the digital excitation adjustor, optimize the parameter of PSS, in this paper, we put up a in-depth study to the principle of MEC5220 digital adjustor produce in Japan by the PSS/E software that develop by the PTI Company in the USA, completed the modeling of the excitation adjustor, PSS, generator, excitor, described the performance of this excitation adjustor, analyzed the essential reason that caused the low frequency oscillation, illuminated the factor that influence the damping characteristic of the MEC5220 digital excitation adjustor. Based on model and emulate, this paper optimized the primary parameter of the excitation adjustor, make a reasonable regulation to the PSS parameter.

为提高核电机组的运行可靠性和接入系统的安全稳定性，防止在外电网的干扰下核电机组发生长时间的低频振荡，保证机组在暂态稳定的前提下提高其稳定裕度，验证秦山核电二期核电机组所配日产MEC5220型数字式励磁调节器参数对机组阻尼的灵敏性，确定数字式励磁调节器的参数的合理性，优化PSS整定参数，本文利用美国PTI公司研发的PSS／E软件对日产MEC5220型数字调节器的原理进行进行了深入细化的研究，完成了励磁调节器、PSS、发电机、励磁机的建模，描述了该型励磁调节器的性能，分析了产生低频振荡的根本原因，阐明了影响阻尼特性的因素。

The thecretical analysis is done for the problems of the integral initial values, the accumulated error and the excursive error induced by numerical integrals. It is found that these errors possess characteristics of lower frequencies and they can be treated as the low frequency noise.

针对积分初值、数值积分积累误差和数值积分引入的偏移误差进行了理论分析，得出此类误差均具有低频特性的性质，可作为信号低频噪声进行处理。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失