查询词典 wave down

The transmit part adopts the phase-locked loop pattern of frequency synthesizing technology and uses the MC145152 and MC12022 chips to compose the phase-locked loop.It locks the frequency of the carrier-wave at 35MHz.The stabilization of the carrier-wave can be 4×10-5,the accuracy can be 3×10-5.The frequency modulation and the confection of the carrier-wave are realized by the capacity-changing diode V149 and the integration voltage-control oscillator MC1648 chip.The end power amplifier uses the audion 2SC1970 to make it work in the third magnifying state,it improves the efficiency of the magnifier and the power of the output reaches the design demand.

发射部分采用锁相环式频率合成器技术， MC145152和MC12022芯片组成锁相环，将载波频率精确锁定在35MHz，输出载波的稳定度达到4×10-5，准确度达到3×10-5，由变容二极管V149和集成压控振荡器芯片MC1648实现对载波的调频调制；末级功放选用三极管2SC1970，使其工作在丙类放大状态，提高了放大器的效率，输出功率达到设计要求。

The auxiliary equation is directly applied to solve the (2+1)-dimensional dispersive long wave equations and the solitary wave solutions and triangular periodic wave solutions are obtained.

利用该辅助方程直接求解了(2+1)维色散长波方程，结果获得了一些孤立波解和周期解，其中包括一些新解。

The first wave were the Gaels; the second wave were the Brythons; third wave were the Belgae

想象：你打开啤酒盖，把啤酒泼在一块巨大的布上，这块布被一只

The first wave were the Gaels; the second wave were the Brythons; third wave were the Belgae, the most industrious and vigorous of the Celtic tribes.

把啤酒泼在一块巨大的布上，这块布被一只鸡想象：你打开啤酒盖从中间飞过去穿了好大一个窟窿。

The first wave were the Gaels the second wave were the Brythons ;; third wave were the Belgae, the most industrious and vigorous of the Celtic tribes.

想象：你打开啤酒盖，把啤酒泼在一块巨大的布上，这块布被一只鸡从中间飞过去穿了好大一个窟窿。

The first wave were the Gaels the second wave were the Brythons 布立吞人 third wave were the ;; Belgae(比利其人, the most industrious and vigorous of the Celtic tribes.

把啤酒泼在一块巨大的布上，这块布被想象：你打开啤酒盖一只鸡从中间飞过去穿了好大一个窟窿。

Week 15 Experiment law of hydrogen atomic spectrum, Bohr hydrogen atom theory, wave -particle dualism of matter, de Broglie waves, uncertainty relation, wave function and its statistical explanation, standard condition of wave function, Schrodingger equation in one dimension, simple introduction of quantum mechanics.

第15周氢原子光谱的实验规律，氢原子的玻尔理论；波粒二像性，德布罗意波，不确定关系；波函数及其统计解释，波函数的标准条件，一维薛定谔方程，量子力学简介。

The voltage wave of open circuit is 1.2/50 μs and the current wave of short circuit is 8/20 μs , which are generated by the combination wave generator through calculating and simulating circuit parameters.

通过计算回路参数及仿真，此组合波发生器能够产生1.2/50μs 的开路电压波和8/20 μs 的短路电流波。

At the same time, combining with the actual condition of delivery pipeline of our country and some prevalent leak detection and location methods, this paper raised a method, which is based on wavelet analysis and negative- pressure-wave to detect and locate the leakage. Jobs in the paper are as follows:As affected by gas density, pressure, specific heat and pipe material, the velocity of negative-pressure-wave improved depending on the energy conservation. At one time, taking the affection of velocity of gas flow, the location formula was modified in some degree.When locating the leaks with location formula, the iterative approach algorithm was adopted as a new method to increase the location accuracy level of system.Multi-scale decomposition and reconstruction of wavelet transform is utilized to filter the noise of negative-pressure-wave, which was brought by leakage. With the capacity to detect the signal singularity fast and accurately, wavelet transform was used to catch the break point of pressure signal. The work improved the accuracy of At in location formula, accordingly improved the location accuracy.Wavelet is a suitable tool for signal analysis. The distinct character is that the mother-wavelet is of optional. That means choosing different mother-wavelet will get different analysis result. So we studied how to choose mother-wavelet and its scale for signal singularity detection. The method is to choose a wavelet by regularities of the wavelet and the signal.Finally, a plan, which bases on SCADA system for inspection and detection of natural gas leakage, is proposed in the article.

其中，主要进行了以下几方面的工作：针对泄漏产生的负压波在管道中的传播速度受媒介的密度、压力、比热及材质等因素的影响，而非声波在空气中传播的速度，本文利用能量守恒原理，对其进行了修正；考虑到管内气体流速对压力波速的影响，对原始的负压波定位公式进行了一定程度的改进，并在利用定位公式进行泄漏点定位时采用逐步迭代逼近算法，提高了系统的定位精度；利用小波变换的多分辨率分解和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行了降噪处理；并利用小波变换技术对信号奇异点的快速、准确的识别能力，对经上述消噪后的负压波信号进行了奇异点捕捉，精确捕捉的结果提高了定位公式中上下游站点采集到的负压波奇异点的时间差△t的精度，从而进一步提高了定位的精度；考虑到小波变换是一种基波可变的信号分析工具，也就是说，不同的小波基波对信号分析的结果将有很大差别，这势必影响最终的处理结果，因此，我们又对比分析了本课题中小波基及尺度的选择问题，依据规则性系数相似性原理对母小波的选择进行了探索性研究；最后，还提出了基于SCADA的泄漏检测与定位系统的软件开发构想及系统的嵌入方案。

Researched influence of frequency on characteristic of electromagnetic wave transmission in tunnels, and analyzed characteristic of electromagnetic wave transmission in circular, arches and curved tunnels by method of metal wave guide, and gives approximate formulas of attenuation rate. Main conclusions we obtain are as follows: in circular,rches tunnels, if frequency is higher, attenuation rate is smaller, it is beneficial for EM waves to transmit, in curved tunnel, higher frequency, more attenuation rate ...

研究了频率对井下电磁波传输特性的影响，采用金属波导法分析了圆形、拱形及弯曲隧道中电磁波的传输特性并给出衰减率近似公式，得出主要结论：在圆形和拱形隧道中，频率越高，衰减率越小，越有利于电磁波的传播；在弯曲隧道中，频率越高，衰减率越大，不利于电磁波的传播；通过特性曲线与井下实验数据相比较得出在900MHz左右为井下无线通信系统传输信号最佳频段。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。