查询词典 ultrasonic frequency

This thesis has discussed the theory of measuring distance in ultrasonic, which include ultrasonic shaking transmit velocity, central frequency, angle of launch control, measure distance, dynamic measure and so on. According to character of wave shape output by circuit, this thesis has designed an efficient way to diminish noise that enables precision of the ultrasonic sensor to 0.2%.

论文详细论述了超声波测距的基本理论，包括超声波震动传播速度、中心频率、发射角控制、发射能量、检测距离、动态检测等；并根据电路输出波形特征设计了有效的降噪方法，使超声波传感器的精度达到了0.2%，然后对降噪后的信号进行了标定。

With the multiple spectrum character of the ultrasonic generator, an impedance model of ultrasonic transducer under the triple frequency harmonic is built.

本文利用超声电源的多频谱特性，推导出超声换能器在谐振频率三次谐波下的阻抗模型。

Objective To study the power spectrum density of blood flow ultrasonic Doppler signal using wavelet analysis. Method Doppler signal of blood flow in human common carotid artery was studied with wavelet scalogram analysis, an affine smoothing Wigner Ville transform with a constant "Q" character. Result Wavelet scalogram of blood flow ultrasonic signal had a higher distinguishability than STFT spectrogram in the low frequency portion, but had poorer decussation terms than spectrogram.

对于平稳信号的处理工具仍然是Fourier变换，但是，在实际应用中的绝大多数信号是非平稳的，现在看来处理非平稳信号的主要工具将是小波变换，这主要是因为传统的Fourier变换分析信号时，时间和频率分辨率精度是固定不变的，而利用小波变换分析信号，在信号高频段时间分辨率精度也较高，在信号低频段频率分辨率精度较高，这很符合非平稳信号的特点。

Based on the principle of ultrasonic cleaning, the working process of the ultrasonic cleaning machine was analyzed including control circuit, driver circuit, frequency tracking,impedance matching and software design.

依据超声波清洗原理，分析了超声波清洗机的工作过程，对超声波清洗机的控制电路、驱动电路、频率自动跟踪技术、阻抗匹配及系统软件设计方法进行了详细介绍。

Characteristic data have been worked out, including the maximum Lyapunov index λ, fractional dimension D, lacunarity Λ and eight energies of various frequency bands. After being normalized, they can function as the characteristic vectors. Then, they are transmitted into an artificial neural network to perform pattern recognition.Starting from the mechanism of ultrasonic generating, initial ultrasonic pulses are calibrated. A stylish discharge source is directly coupled with the ultrasonic sensors, and work out actual discharge magnitude.

利用非线性和非平稳的方法对超声波信号进行了分析处理，对于局部放电模型得到的信号，计算了超声波信号的Lyapunov指数、分维数D、空缺率、小波包分解的8个频带能量，得到了11个特征数据，归一化处理后形成特征向量，由人工神经网络进行识别，实现了对局部放电典型模型的模式识别，显著提高了模式识别的正确率，并分析了传播途径对识别的影响。

The spectrum analysis of the air-ultrasonic waveform indicates that when the matcher thickness is calculated at the highest spectrum and the subsequent higher spectrum of the pulse waveform, it can obtain a better result. But all the highest spectrum of the air-ultrasonic waveform moves to the high frequency zone in the experiment, which is a possible important reason that the testing extent of the air-ultrasonic transducer is limited.

经对空气超声波形进行频谱分析后发现用脉冲波形的最高谱线及次高潜线对应的频率计算匹配层厚度，可得到较好的匹配结果，但是空气超声波形的最高谱线均移向高频段，这可能是造成脉冲空气超声换能器可检测的范围有限的一个重要原因。

Ultrasonic is a kind of mechanical wave that frequency is upper 20KHz. Ultrasonic may be generated by many ultrasonic transducers.

超声波是频率高于20KHz的机械波，它可由多种能量转换器转变而成。

Ultrasonic is one of mechanical wave with wave frequency scope 20-106 KHz, Using Ultrasonic to accelerate or generate a new reaction is its new pattern arisen intercross course.

超声波是频率范围20-10~6KHz的机械波，利用超声波来加速或引发新的反应是一门新兴的交叉学科。

On the basis of investigating the sound field of a plane piston transducer and the relations between sound field and radiation force, by settling four plane piston transducers driven at the same frequency at each corner of a regular triangular pyramid with their sound-beam axes crossing at the center of the pyramid, this technique uses ultrasonic wave synthetic theory to acquire a three-dimensional ultrasonic standing wave field. The micro-component can be captured, transported, released in the range of space by adjusting the phase of the transducers.

在研究单个圆形平面活塞换能器声场分布以及声场和辐射力关系的基础上，将以相同频率驱动的4个平面活塞换能器呈正四面体放置，利用声波合成原理获得三维超声驻波场，通过调整各个换能器发射信号相位之间的关系实现对微构件在空间范围内的俘获、移动、释放等操纵。

Refining a variety of high-frequency plastic welding machines, high-frequency fusing machine, high-frequency metal heat treatment machines, wide-band ultrasonic machine, blister sealing machine, heat shrink packaging machine and other packaging equipment!

精制各种高周波塑胶熔接机，高周波熔断机，高周波金属热处理机，全频段超声波机，吸塑封口机，热收缩包装机等各种包装设备！

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。