负偏斜分布

The following results are documented:(1) the skewness has a characteristic of time-varying law whether in the returns of Shanghai stock market and Shenzhen;(2) the negative skewness in Chinese stock market returns can be partly explai.

股票市场通常易于发生大幅下跌而非上涨，即指数收益率的分布往往具有负偏斜的非对称特征。

On the basis of previously research, this paper re-probe into the mechanism of electro-chemist mechanical manufacturing process, making the rational technological parameter, and developing the manufacturing equipment. Through a lot of technology tests, get a lot of labratory data, accordingly, researched the surface feature of the electro-chemist manufacturing process, and deeply discussed its influence on the work piece feature. The last result is that: the electro-chemist mechanical manufacturing process can reduce the low-frequency component significantly, but on high-frequency component, it has little influence, having obviously positive pole flat effect. After manufacture, the tip parts on the surface of the work piece is cut off, there is micro "high land" shape, the parameter for surface roughness is reduced a lot, the surface outline of the work piece is negative, the bearing length rate is cliffy. Also the surface quality of the work piece is improved. This can help to avoid changing the shape, improve the feature of rub, gear and reduce the time to suit. This would also ensure the precision and result in a longer work piece life.

在以前研究的基础上，本论文重新探讨了电化学机械复合光整加工工艺的机理，确定了较合理的工艺参数，对电化学机械复合光整加工设备进行了改进，通过工艺实验广泛地搜集了大量实验数据，依据实验数据，多角度地研究了电化学机械复合光整加工的表面形貌特点，并且从理论上深入讨论了电化学机械复合光整加工表面形貌对工件工作性能的影响，最后得出的结论为：电化学机械复合光整加工对工件原始表面的低频成分有较大程度的降低，而对高频成分影响较小，有明显的阳极整平作用，被加工工件表面的尖峰状凸起被去除，工件表面呈现出微观&高原型&，表面轮廓不平度高度特性参数大幅度降低，工件表面轮廓分布集中，且呈负偏态，轮廓偏斜度为负值，轮廓支承长度率曲线陡峭，工件的表面质量得到综合改善，这对提高零件的抗接触变形能力、改善摩擦、磨损性能、降低工件的磨合时间、提高工件的精度保持性、延长工件的寿命均有利。

If you are unfortunate enough to the lovelorn, please tell me, I will help you out, really, please contact me!

如果你不幸失恋了，请告诉我，我会帮助你摆脱困境，真的，请联系我啦！

China's plan to cut energy intensity by 20 percent and pollutant discharges by 10 percent between 2006 and 2010 is a case in point.

中国计划在2006年到2010间降低20%的能源强度和减少10%的主要污染物排放，就是一个这样的例子。