能量守恒

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。

There is also no violation of the law of conservation of energy.

这根本就不违反能量守恒定律。

This sweeping generalization is the law of conservation of energy.

这一透彻的概括就是能量守恒定律。

Material eternal law and the law of conservation of energy is the great law of nature.

物质不灭定律和能量守恒定律，是自然界的伟大定律。

Now, material immortal declaration and observe energy conservation law has been mastered by millions of people.

现在，物质不灭宣告和能量守恒守律已经被千百万人所掌握。

Then, based on conservation of energy law, the physical cause of it was analyzed.

然后根据能量守恒原理，分析了混凝土浇筑结合面上节点初始温度取值不同时，造成温度场计算值与理论分析值偏差的物理原因。

We believe that the law of conservation and conversion of energy will ultimately assist scientists in achieving the grand unified theory.

我们相信能量守恒和转换定律将最终帮助科学家实现微观和宏观物理理论的"大统一"。

Starting from the conditions of law of conservation of energy and angular momentum,how to deal with simple disposal of several physical equations of the planetary motion by applying the elementary mathematical equations is proposed.

从角动量和能量守恒定律出发，建立行星椭圆运动的轨道方程，导出行星运动时的各个物理量表达式，从而给出了一种以初等数学为基础的处理行星运动的简洁方法。

Conservation of matter and energy in the universe.

宇宙的物质和能量守恒。

And meanwhile, the conservation of mass, momentum and energy were discussed.

同时讨论此技术实施过程中伴随的质量、动量和能量守恒问题的解决办法。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。