查询词典 break-even point

Because the temperature along the pipeline is not a constant, it changes the velocity of the negative-pressure-wave; the Romberg algorithm of numeric integral and the searching for algorithm are emloyed to locate the leakage.Multi-scale decomposition and reconstruction of wavelet transform is applied 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 Δt in location formula, and the location accuracy is improved.

利用小波变换的多分辨分析和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行了消噪处理；并利用小波变换技术对信号奇异点快速、准确的识别能力，对经过消噪处理后的负压波信号进行了奇异点捕捉，准确确定了定位公式中上、下游站点采集到的负压波奇异点的时间差△t，从而提高了定位的精度。

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。

With her point of view clearcut, Lokhart choses to confine herself to one place, one space in time: the lunch break of the workers, who sit opening their lunch boxes all the way along an interminably long corridor midst the machines, is filmed in a single, slow motion travelling shot.

Lokhart决定将自己现在在同一时间内的一个空间内，就是电影中用一个缓慢的移动镜头所拍摄的场景|：员工们的午餐时间—坐在机器之中长长的走廊上，打开饭盒开始吃饭。

On November 4 in the evening, netizen " I am not earthy cootie " the measure for measure is sent in skyline forum post, point out the driver is ground pressure the doggie is wrong really, but " Hua Suzi " the privacy right that ignores other starts person pork blindly to search, it is typical deliberatelly break the law.

然而，部分理性网友认为通缉行为侵犯了车主的隐私权。11月4日晚上，网友"我不是土虱"针锋相对地在天涯论坛发帖，指出驾驶员碾压小狗的确有错，但"花素子"无视他人的隐私权盲目发动人肉搜索，是典型的知法犯法。

The main direction to reduce decollation rate of yarn is to control and stabilize yarn tension, increase the yarn mightiness and reduce weakness tache rate, especially cut down the break tension and mightiness weakness point to reduce the cross rate of tension wave crest and mightiness wave trough.

由气圈理论的研究我们可以得知：降低断头率的主攻方向是控制和稳定张力，提高纺纱强力、降低强力不匀率，尤其是减少突变张力和强力薄弱环节，以减少张力与强力的波峰与波谷交叉机率。

A perfect circle does not have a discernable beginning or end -- therefore, it doesn't have a weak point where you can break it.

一个完美的圆形没有一个有迹可寻的开始或结束-因此，没有一个薄弱点，您可以打破它。

When Walt was deep in thought he would lower one brow, squint his eyes, let his jaw drop, and stare fixedly at some point in space, often holding the attitude for several moments… No words could break the spell…

每当Walt Disney变成梦想家，他的同僚对他的动作有这样的描述：每当迪士尼在深思的时候，他会低下额头，眼睛斜斜的望着，放下自己的下巴，凝视着某一个定点，并持续这种态度好一段时间……也没有别的话语能打破这种静默。。。

Edger took the view that Chinese control over central Tibet would be preferable from the missionary point of view because it would break the power of the monasteries and make it possible for missionaries to work in comparative safety

Edger认为，从传教士的角度说，中国对西藏腹地的控制是更好的，因为这样以来就可以打破寺院的权力，并让传教士在一个更安全的社会工作

It reports that two-thirds of the women who had not already had a "career break", as it is euphemistically known, planned to take one at some point in the future. Less than an eighth of men had similar aspirations.

它报告说，三分之二已经没有"工间休假"（这一休假已经婉转地为人们所知）的女性，计划在将来的某个时候要一个孩子，只有不到八分之一的男性有类似的期望。

The thought based on the hyperbola function method is extended,and more explicit and exact solutions are successfully derived,including shock wave type solutions with break point and exponential function type solutions .

在此基础上又对双曲函数法的思想进行了推广，从而获得了其更多的显式精确解，包括间断型激波解和指数函数型解。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。