差

MGM is introduced to solve field distributions in 3-D electron optical systems. The difference equation, the discrete form of Laplace's equation, is deduced in 3-D Cartesian coordinates. In view of the smooth effect, MGM combines Gauss-Seidel iteration with a technique known as coarse grid correction. Formulae for restriction and prolongation are deduced and expressed in terms of tensors.

将多重网格法引入电子光学系统中三维静电场的计算，对三维笛卡尔坐标系中的差分方程，采用高斯-赛德尔迭代法求解差分方程组，并结合迭代过程讨论了粗网格的误差校正技术；在不同网格层之间进行场值的限制和延拓，推导了三维静电场中的限制、延拓公式并以张量的形式表示。

If one supposes, as I think is reasonable, that if one is talking about physicists at a top twenty-five research university, one is not talking about people who are two standard deviations above the mean.

我们假设，我觉得这是合理的，比方说在最好的25所大学里的物理学家们，这些人恐怕不是高于均值两个标准差，甚至都不止三个标准差。

As a measure of risk, mean absolute deviation is better than variance in a sense.

作为度量风险的标准，绝对离差比方差更为合适。

In this paper,a portfolio choice model is proposed based on mean absolute deviation.

用绝对离差刻画了风险，提出基于绝对离差的证券组合投资模型，并用模拟退火算法求解。

Earlier, when we calculated the range, the interquartile deviation, and average absolute deviation, the answers were expressed in the same units as the data itself.

当我们计算极差，四分点离差和平均绝对偏差时，答案的计量单位与数据单位量相同的。

For example, in bondid hygrogram, the absolute humidity bleaching Board for up to 6%, and the absolute unbleached kraft paper up to 7.5% humidity.

例如，在相的湿量下，不染黑纸板的绝差湿量可达6%，而未不染黑牛皮纸的绝差湿量可达7.5%。

Due to the possibility of reducing risk through diversification, the risk of portfolio, measured as its variance , will depend not only on the individual variances of the return on different assets, but also on the pairwise covariances of all assets.

风险可以用方差来衡量，通过分散化可以降低风险。投资组合风险不仅依赖不同资产各自的方差，而且也依赖资产的协方差。

Fluxgate sensor inducts the environment magnetic field, outputs the compass course signal to the CPU system. This signal then is transformed into digital signal. CPU processes it and then gains compass course. When use rotary mathod to measure the deviations, CPU first collects timed the compass course come from the Fluxgate sensor, then calculates automatically their deviations and the correspondent coefficients. Based on all this, CPU can calculates out the real-time magnetic course or the real-time ture course, then sents them to display on the digital displayer.

本系统采用磁通门传感器来直接敏感合成磁场，输出罗航向直流感应电压信号送A/D转换器进行转换，并经CPU计算处理得到罗航向度数值，以及利用&旋回法&测定自差时，CPU按照船舶旋回的角速度定时地采集罗航向度数值，在此基础上CPU自动地计算出各采集罗航向上的白差，再由此计算出自差系数，并实时地解算出磁航向值或真航向值，送数码显示器显示。

This demonstrates that it is necessary to carry out variance-covariance component estimation for the double-differenced GPS observables.

结果 两种方法估计的方差－协方差阵都与常用的先验协方差阵有明显区别；两种方法估计计算结果非常接近。

The strongly negative correlation between winter sea-ice extent of Davis Strait and August rainfall of North China turns into bad correlation.

冬季戴维斯海峡海冰面积和北半球夏季、7月500Hpa位势高度场年际关系的年代际变化主要是相关系数分布型的变化：1974年前，相关系数分布型呈一个自新地岛开始经巴尔喀什湖到日本海的&-+-&型，该型和同期华北降水的反相关较好；1974年后，相关系数分布型变为呈自乌拉尔山开始经贝加尔湖到河套的&+-&型，该型和同期华北降水相关差。1974年前，冬季戴维斯海峡海冰面积和北半球8月500Hpa位势高度场的相关系数呈一个自乌拉尔山开始到鄂霍次克海以北分布的&+-+&型，该型和8月华北降水的反相关较好；1974年后，相关在欧亚大陆地区变差，没有明显的相关型，冬季戴维斯海峡海冰面积和8月华北降水关系变差。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。