高频率的

Therefore the dispersion curves obtained in the field are primarily consisted of the first mode. For a heterogeneous elastic solid consisting of three homogeneous layers whose interlayer has low velocity, the phase velocity V〓 of the first mode will also close up to the Rayleigh wave velocity of the bottom layer when frequency f→OHz, but V〓 of the first mode will close up to the shear wave velocity of the interlayer when f→∞, and there is a cut-off frequency at high frequency region for the first mode and V〓 close up to the compressional velocity of interlayer when interlayer is liquid.

当三层固体介质中存在软夹层时，若f→OHz，则其基阶模式的相速度V〓→V〓（V〓为最底层介质的瑞利波速度）；若f→∞，其基阶模式V〓→V〓（V〓为中间层介质的横波速度）；若三层介质中存在液体夹层，当f→OHz时，基阶模式V〓→V〓，而基阶模式在高频段存在一个截止频率，截止频率处的瑞利波速度V〓→V〓；由此可判定，野外实测的相速度频散曲线不仅有基阶导波模式，同时还应有高阶导波模式波的存在，接收信号中存在模式间的跳跃，因此频散曲线会产生"之"字形现象。

Based on a profound study of the variation law of phase difference between two periodic signals and the ordinary frequency measurement method, this paper presents a new method for comparing frequency standards, which is based on the Lissajous figure.

用传统的李沙育图形法是不能完成对高精度频标比对的，但将等效鉴相频率这一新概念引进，可以使得本来不能完成的高精度频率标准的比对变为可能。

On the disribution transformer, whose impedance is independent of varying load while the frequency is higher than 25KHz, and the parallel resonance frequency of which is in 3~10 kHz.

由探讨知，杆上配电变压器的并联共振频率约在3~10kHz之间，在此频率范围，信号的分路损失最小，又载波频率高於25KHz时，其分路损失几与负载的变动无关。

Log-domain companding technique takes advantage of the exponential I/V characteristics of the active devices such as bipolar junction transistors, compressing the dynamic range of the input sigal and reducing internal voltage amplitudes, it can maintain large dynamic range and high operating frequency under low supply voltage , the main area of application for this technique is the implementation of continuous-time fully integrated filters with low voltage, wide dynamic range, high-frequency, and wide tenability.

对数域压扩技术利用BJT晶体管等有源器件的指数Ⅰ-Ⅴ特性，对信号作对数压缩处理，大大降低了电路内部节点电压的摆幅，能在低电源电压下保持大信号动态范围和高工作频率，该技术的主要应用是设计具有低电压、宽调谐范围、高工作频率和宽动态范围特性的连续时间全集成滤波器——对数域滤波器。

Result proves that ultrasound frequency is higher in the same time, lethality rate increases with the increase of radialization time on the same frequency, at the same time, its physiological character changes.

试验结果表明，在相同的时间内，超声波频率越高对试验菌株的致死率越高；同一频率，超声波辐射时间增加也可使试验菌株的致死率增高，同时经过诱变处理后的菌株其生理生化特性也有变化

A novel microemulsion was prepared to increase the solubility and enhace the in vitro transdermal delivery of OXA. For the microemulsions, types of oil phase, surfactants, cosurfactant were chosen and the double-distilled water was purified as water phase.

奥沙普秦玻璃酸钠凝胶的流变学实验结果显示，药物玻璃酸钠凝胶具有假塑性流体特性，在低剪切频率时具有较高的黏度，而在高剪切频率时具有较低的黏度，有利于制剂在皮肤表面的涂布和黏附。

DG1000 operates direct figure to synthesize science and technology, the random that can output an user to be defined oneself is undee, have rich input output, and frequency meter of high accuracy, broad frequency band, frequency limits 100MHz arrives 200MHz, frequency resolution achieves 6 / second.

DG1000操作间接数字分解科技，可输出用户自界说的任意波形，领有丰硕的输入输出，以及高精度、宽频带频率计，频率规模100MHz到200MHz，频率分辨率达到6位/秒。

A novel quasi-constant frequency hysteresis PWM control approach is presented in this paper. Frequency feedback is introduced in hysteresis current control to stabilize switching frequency. Comparing with the common used constant frequency current mode control, the new approach has better stability, faster transient and higher precision, as well as elimination of sub-harmonic oscillation.

摘 要：本文提出了一种新的准固定频率滞环PWM电流控制方法，该方法在滞环电流控制的基础上，引入频率反馈控制，使开关频率基本固定，解决了目前广泛使用的固定频率电流控制方法具有的次谐波振荡的问题，并且具有稳定性好、相应速度快、控制精度高的优点。

The end linking the timing gears cap, the side wall of cylinder and the skirt section of the engineblock are the sound radiation resources of the two engineblock sides. Except that, this thesis calculates sound power level of radiated noise from the engineblock with MATV method. It is found that the noise radiated from the engineblock is slightly loud.

此外本文还应用MATV法计算了气缸体辐射噪声的声功率级，通过声功率级的计算发现：气缸体的辐射噪声偏高，达到了108.84dBA，并且在850Hz时，由于气缸体的激励频率与其第八阶固有频率相等，气缸体发生了共振，因而在该频率时，气缸体的辐射噪声最大，所占气缸体表面辐射噪声总能量比重也最高，该频率应该是本文噪声控制关心的重点。

Due to the frequency selectivity and high insertion loss of SAW device , t he inp ut must be high p ul se whose spect rum widt h can cover t he center f requency of SAW tap delay line.

由于 SAW 器件具有频率选择性及较高的插入损耗，使得它的输入必须为高脉冲且脉冲的频谱宽度能覆盖 SAW 抽头延迟线的中心频率。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。