衰减器

Experiments prove that the notch attenuation value can reach -330 dB at arbitrary frequency by adjusting phase-shift parameter.

实验表明：通过改变相移参数值，在任意频率点上陷波器的衰减值可达-330 dB。

A sectional hyperbola cylinder sound lens using for oil recovery is designed according to the refraction law of sound.

对于一定的油井，无法改变油井中的原油及其岩层对超声波的衰减作用，但是，利用声透镜可以改变超声换能器所辐射出的超声

Position parameters were obtained from the simulation with the model of towed array.Based on the theory of radiated noise forming, the launch noise was simulated according to test condition in Laboratory,and the result showed the launch impulsion noise obeyed SαS distribution. The simulated noise attenuating in deep sea was analyzed with a sound loss translation model.Minimum variance distortionless response,spatially smoothed MVDR, and beam-space multiple signal classification algorithm were adopted to process the signal, hence the source level, the frequency structure and the location of the launch noise were achieved.

基于试验的实际情况，根据潜艇拖曳阵模型，仿真生成了各水听器阵元与本艇的位置关系；根据噪声源理论模型分析产生雷弹发射模拟噪声，利用SαS分布模拟武器发射冲击噪声，仿真分析模拟噪声在海洋环境中的传播衰减，对阵元信号分别利用最小方差无畸变响应法（MVDR 、空间平滑MVDR以及适应子带的波束域多重信号分类算法进行信号处理，得到发射噪声的声源级、频谱结构和方位。

Based on the well-know Pennes'' bioheat equation,we calculated theoretically temperature field of HIFU-induced BFR in tissue,and measured spatial temperature rise in BFR induced by HIFU in freshly excised cow liver at constant acoustic intensity and exposure time, and studied the effects of the physical parameters of focused ultrasound transducer such as frequency,outer radius and curvature radius,focal depth, and acoustic intensity and exposure time on the temperature field of HIFU-induced BFR.

采用生物热传导方程理论计算了HIFU生物学焦域温度场，采用微型热电偶探针测量了HIFU辐照离体牛肝时靶组织温度分布；研究了聚焦超声换能器的物理参数、辐照深度和治疗剂量对HIFU生物学焦域温度场的影响；研究了HIFU在牛肝组织中的传播衰减。

As in the case of input resistance voltage loading, the shunt resistance and the source resistance form a voltage divider that reduces the measured voltage as follows

和输入电阻的电压负载作用一样，分流电阻和源电阻也形成了一个分压器，并将测量的电压衰减如下

The result indicates that the output power oscillates and weakens along with increasing input power,and its oscillation period depends on the distance between the medium and beam focal point.Limiter′s limiting ability will decrease if waist size of the incident Gaussian beam and the aperture size increase.With a fixed input power scope,medium′s best limiting position will move towards the focal point if waist size of Gaussian beam and the aperture size increase,but the best limiting position will change a lot with different input power scopes.

结果表明：限幅器的出射功率随入射功率的增加衰减振荡，其振荡周期取决于介质相对于光束焦点的位置；限幅器的限幅能力随入射光束腰半径和光阑孔径的变大而减弱；入射功率范围固定，入射光束腰半径和光阑孔径增大时，介质的最佳限幅位置向入射光束的焦点靠近，但是在某些入射功率范围内会存在多个最佳限幅位置；光限幅器的箝位输出功率随光阑线性透过率的增加存在线性增加和非线性增加两个不同区域，实际应用中应在线性增加区域确定光阑孔径的大小。

The adjustment principle of the system is analyzed and the transmission curve under the different rotation angle of circular polarizer is shown.

对衰减系统的调节机理进行了分析，并给出圆偏器旋转不同角度下系统的透射曲线。

The first kind of method includes voltage divider of a double resistor and an output amortize; The 2nd kind of method includes an inverter that has very big attenuation.

第一种办法包括一个双电阻分压器和一个输出缓冲；第二种办法包括一个存在很大衰减的反相器。

The inspection for [3 改为of] wave trap combined the high frequency filter characteristics, is often judged by using to test the impedance of the wave trap, the echo depletion and the attenuation.

对阻波器、结合滤波器的高频特性检查，在实际应用中常采用测试阻波器的阻塞阻抗以及测量滤波器的回波损耗和工作衰减来判断好坏。

We apply the soft output and the soft decision feedback structure to the MLP/BP-based channel equalization scheme that concatenates with the soft decision channel decoder to improve whole performance on multi-path fading channels.

在多路径平坦衰减通道中，我们应用软性输出和软性决策回授的结构於一个以多层认知器结构倒传递类神经网路为基础的通道等化器，并於其后串接一个软性决策通道解码器以改进整体的效能。

And Pharaoh spoke to Joseph, saying, Your father and your brothers have come to you.

47：5 法老对约瑟说，你父亲和你弟兄们到你这里来了。

Additionally, the approximate flattening of surface strip using lines linking midpoints on perpendicular lines between geodesic curves and the unconditional extreme value method are discussed.

提出了用测地线方程、曲面上两点间短程线来计算膜结构曲面测地线的方法，同时，采用测地线间垂线的中点连线和用无约束极值法进行空间条状曲面近似展开的分析。