声压

The low-frequency noise in the structure-acoustic field coupling system of high-speed train was simulated and analyzed.

对某高速列车拖车的仿真分析结果表明：该车声学测试点的总声压级超出了TB 1809—86标准拖车客室的容许噪声值；在某些计算频率下，车体某些部件涂敷阻尼材料后对客室测试点的声学贡献由小变大，这说明阻尼材料不仅改变了这些部件的振动幅值，同时也改变了振动相位。

The treatments began one hour before a five-hour exposure to 120 decibel sound pressure level noise, and continued once daily for five days.

治疗开始前一小时5小时暴露在120分贝声压水平的噪音，并继续每日一次连续5天。

Experimental results of the second harmonic sound pressure level(SPL2)curves in frequency domain show that Prof.MAA's theorydescribes the behavior of the second harmonics satisfactorily in whatis called "Steady Region" of standing wave field.

频域内，大振幅驻波场二次谐波声压级曲线的实验结果，确认马大猷教授的理论为驻波场&稳定区&的极好描述，所提理论在本实验研究中，得到了肯定结果。

The 3190 can handle 350 watts into 4 ohms with an SPL of 122dB from two 8 inch woofers alongside two 25mm tweeters.

在3190可以处理350瓦的一二二分贝声压级为4欧姆，从2 8 2 25毫米高音喇叭旁边英寸低音扬声器。

It for the whole two hours frequency range speakers, and the use of high-grade titanium membrane modules Treble and bass is a high-grade cast iron and aluminum Penjia-line voice coil. Sound pressure, males, trapezoidal box design, exterior paint is imitation effect.

它为二分频全音域音箱，采用高档的钛膜高音单元，低音是高档的铁铸盆架和铝扁线音圈，声压高，爆发力强，梯形箱体设计，外观是仿喷漆效果。

Resonance frequency, resonance amplitude and radiation pressure are related to the distance between the two bubbles.

共振频率，共振振幅及声压与两气泡之间的间距有关。

By means of the present model certain phenomena related to the nonlinear acoustic properties of an orifice, such as the roll-up of the shed vortex sheet and the forming of the Vena-Contracta are simulated. For a sinusoidal sound pressure, the time- history of the average velocity through the orifice is computed, and the nonlinear distortion of the velocity is examined by means of the Fourier decomposition.

依据此模型，对圆孔声学非线性效应的若干特征现象进行了数值模拟，如脱落涡层的卷曲，Vena收缩段的动态形成；在孔板前声压按余弦规律变化的情况下，计算了孔中平均速度的时间历程，并借助于Fourier分解分析了孔中平均速度的畸变情况。

Low noise level can be achieved with trim thathasan exit velocity head higher than 480 kPa.

在阀门内件节流出口速度头高于480KPa的情况下，低的阀门声压级仍能实现。

On the other hand,avalvetrim exit velocity head lower than 480 kPa will have a veryhighnoise level if the valve outlet mach number is notlow.

另一方面，当阀门的阀门内件节流出口速度头低于480KPa时，如果阀门的出口马赫数不处于较低的水平，阀门仍会有较高的声压级。

Also,this article willshow thathaving a trim exit velocity head lower than 480 kPa willstillgenerate a very high valve noise level if the valve outletMachnumber is high.

另外，这篇文章显示在流体速度头低于480KPa，但阀门出口流体速度马赫数较高的情况下仍会产生相当高的声压级。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。