衰减

The transient is seen to be a decaying exponential, and the commonly used measured of the speed of decay is the time constant: The time constant is the time in seconds for the decaying exponential transient to be reduced to e-1=0.368 of its initial value.

瞬态解看上去为指数衰减的，且通常用于衡量衰减速度的是时间常数：即指数衰减的瞬态解衰减至其初始值的 36.8%所需的时间。

And the influence factors such as suspension concentration,operating pressure,Reynolds number and Euler number were established.

结果表明，死端过滤速率衰减模型中过滤速率与时间呈幂函数关系、而十字流过滤速率衰减模型中过滤速率与时间则呈一次函数关系，死端过滤时悬浮液浓度和气压过滤压力对其过滤速率衰减模型系数的影响均呈三次函数关系，在十字流过滤时悬浮液浓度、操作压力以及雷诺数对模型系数b的影响均呈线性关系，轴向流十字流过滤速率衰减模型系数b与欧拉数呈反比，而旋转流十字流过滤时则模型系数a与欧拉数呈反比关系。

The experimental results revealed that 60% of cell decay in a nitrifying system was caused by activity decrease and 40% was caused by cell death. In a heterotrophic system, however, activity decrease was responsible for 80% of cell decay, and the other cell decay for 20% was caused by cell death.

结果表明，硝化系统细菌在衰减过程中由细胞活性降低引起的衰减约占60%，由细胞死亡引起的衰减约占40%；而在异养系统中由活性降低引起的衰减和由细胞死亡引起的衰减分别为80%和20%。

7 To 3.3 V operating supply voltage 44.1 kHz sampling frequency 16.9344 MHz (384fs) system clock Built-in crystal oscillator circuit 16-bit, MSB rst, rear-packed serial data input format ( 64 fs bit clock) 8-times oversampling digital lter · 32 dB stopband attenuation ·+0.05 to -0.05 dB passband ripple Deemphasis lter operation · 36 dB stopband attenuation ·-0.09 to +0.23 dB deviation from ideal deem- phasis lter characteristics Attenuator · 7-bit attenuator (128 steps) set by microcontrol- ler Soft mute function set by parallel setting ·(approximately 1024/fs total muting time) Mono setting · Left or right channel mono selectable by micro- controller Built-in innity-zero detection circuit , two-channel D/A converter · 3rd-order noise shaper · 32fs oversampling Built-in 3rd-order post-converter low-pass lters 24-pin VSOP package Molybdenum-gate CMOS process

2.7至3.3 V工作电源电压为44.1千赫的采样频率16.9344兆赫（384fs）系统时钟内置晶体振荡器电路的16位，MSB在前，后包装的串行数据输入格式（64飞秒位时钟）8倍超采样数字滤波器·32分贝的阻带衰减·+0.05至-0.05分贝通带纹波去加重滤波器的运作·36 dB抑制频宽衰减·-0.09到0.23 dB的偏差认为不理想，症状困扰评估滤波特性衰减器·7位衰减器（128级）集由单片机在-莱尔软静音功能的平行设置·（共约1024/fs静音时间）单声道设置·左或右声道单声道微控制器可选的内置的无限零检测电路Δ，两通道的D / A转换器·第三阶噪声整形·32fs过采样内置三阶后转换器的低通滤波器24引脚VSOP封装钼栅CMOS工艺

So in fact, if they senesce just a tiny tiny bit over time -- that is, if their half-life gets shorter, very very slowly -- we wouldn't actually be able to tell that this was happening in the time that we took our measurements, because the acceleration in the rate of atoms decaying (relative, of course, to the number that had not decayed already, which is always decreasing) would be too tiny to be statistically detectable.

所以在事实上，如果它们随时间衰老得只那么一点点，—就是说，如果它们的半衰期缩短得非常慢—那么我们实际上不可能知道，在我们测量期间发生过衰减，因为原子衰减的速率加速得太小，统计学上检测不出（当然，是相对于不曾衰减的数目而言，不曾衰减的原子数目总是在减少）。

Low-frequency covibration experiments of four kinds of fluid-saturated feldspar sandstones which have different viscosity coefficients respectively were conducted so as to know how fluid viscosity coefficient influences attenuation, modulus and velocity dispersion in fluid-saturated sandstone.

为了探讨孔隙流体的黏滞系数对饱和砂岩的衰减、模量和速度色散的影响，本文进行了四种不同黏滞系数的饱和长石砂岩的低频共振实验，结果发现在0.01～10Hz频带范围内，无论是衰减温度话还是衰减频率谱，都显示出衰减随黏滞系数的增大成良好的线性增长关系，黏滞系数越大楼量越大；同时还具有明显的模量与速度色激，而且随着黏滞系数的增大，模量与速度色权有增强的趋势。

In the BNR system (SRT=15 d), the cell death was responsible for 45% of the total cell decay for nitrifying bacteria, and thus the activity decay accounted for 55% of the total cell decay.

在BNR系统中（SRT=15 d），硝化细菌在衰减过程中由细胞死亡引起的衰减约占细胞总衰减的45%，由活性降低引起的衰减约占细胞总衰减的55%。

So, the proportion coefficient in the damping region is changed from constant to variable. Setting the damping region as the same thickness, the transition region is located in the damping region. In the transition region, the proportion coefficient increases and reaches a constant in the end.

为此，对Sarma吸收边界条件进行了改进，将衰减层内所采用的恒定比例系数改为变比例系数，即在衰减层厚度相等的条件下，在衰减层内设置一个过渡带，在过渡带比例系数由小变大，在衰减层内比例系数取恒定值。

The computationresults show that for a organ-pipe nozzle with a given configuration size, the nondimensional axial velocity attenuates slower with the increase in stand-distance, and the nondimensional axial velocity attenuation pattern remains the same, and the nondimensional axial velocity along the jet centerline attenuates slower with the increase in distance between the nozzleexit and the impinging plate.

计算结果还表明：对给定结构尺寸的风琴管喷嘴，随着喷距的增加，沿径向的无因次轴向速度衰减变慢、沿径向无因次轴向速度衰减规律不随喷速的变化而变化；无因次轴心速度的衰减规律随着喷嘴出口到井底间距离的增大，射流轴心速度衰减变慢，但其变化幅度不大；在固定靶距情况下，无因次轴心速度衰减规律不随喷速的变化而变化。

The results show that this attenuator, which is 12mm×8mm×0.5mm and works at low temperature, can be used alone or integrated into HTS system to decrease system volume and weight. Insertion loss of this attenuator is about 0.2dB, whose magnitude is one order lower than that of a conventional attenuator. Attenuation step about 0.01dB can be achieved, which is 1~2 orders lower in magnitude than conventional attenuators.

主要结论如下：光控高温超导微波可变衰减器在液氮温区工作，电路尺寸为12mm×8mm×0.5mm，可单独使用也可集成于高温超导系统中，可大幅减小系统的体积与质量；高温超导衰减器的插损小于0.2dB，比常规衰减器低1个量级；高温超导衰减器的可变衰减步进值小于0.01dB，比常规衰减器低1~2个量级。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。