一阶导数

In this paper, a new approach for automatic extracting the local maximum lines from the first horizontal derivative images of geophysical fields is proposed.

提出了一种自动提取地球物理位场水平一阶导数图象中局部极大值线的有效方法。

This can be done adding a penalty term into target function used in the standard BP algorithm, and the penalty term is related to the first derivative of the target function.

具体的做法是在标准BP算法中的目标函数项内增加一惩罚项来完成的，而此惩罚项与目标函数的一阶导数相关。

The first derivative spectra have been applied to develop this model. This model has been optimized by selecting the best wavelength range and the most suitable factors.

为了优化模型，我们对白酒的近红外光谱进行一阶导数处理，选择最佳的波长范围和最适的因子数。

The spectra, which were pretreated with the method of first derivative combined standard normal variate, were analyzed by principal component analysis.

将经一阶导数结合标准归一化处理后的光谱进行PCA降维，以前20个主成份（含原始光谱86.09%的特征信息）为输入变量，建立杂交稻种纯度鉴定的BP-ANN模型。

The study showed that spectra information can be extracted thoroughly by the pretreatment method of first derivative combined with standard normal variate, with the SEC of 0.002 5, SEP of 0.006 6, and determination coefficients of 0.988 4 and 0.922 7 respectively.

分析表明采用一阶导数结合标准归一化处理能最有效地提取光谱信息，此时PLS模型校正集决定系数与检验集决定系数分别为0.988 4与0.922 7，校正标准误差与预测标准误差分别为0.002 5与

The NIRS quantitative analysis model was developed for measuring MBM content in fish meal by using partial least squares. The initial spectrum was pretreated by standard normalized variate, 7 point smoothind and one derivative respectively.

应用偏最小二乘定标方法，在8 678.10~4 250.34cm^(-1)波数范围内，采用变量标准化、7点平滑和一阶导数对光谱进行预处理，建立了鱼粉中肉骨粉含量的NIRS定量分析模型。

Three different numerical iterative algorithms are developed and the accuracy and stabilities of them are compared. Tension and compression instabilities are studied and effects of Conservative Smoothing Approach and artificial viscosity on stabilities are discussed. Based on Taylor series expansion, Modified SPH method is proposed. The discrete forms of the function and its first derivative estimations of the kernel function are deduced in both one and two dimensional space.

讨论了三种不同的数值迭代算法对计算精度和稳定性的影响；分析了不稳定性产生的根源，包括拉伸不稳定和压缩不稳定，探讨了保守光滑算法和人为粘性对稳定性的影响；在Taylor展开的基础上提出了一种修正的SPH方法，并推导一维和二维情形下函数的核估计和函数的一阶导数核估计的离散形式，结果表明，二维情形下MSPH方法可以很好的改善边界粒子的计算精度。

A new dynamic sliding mode control law is presented for tracking control of robot manipulator.New switch function based on backstepping method is designed to transfer discontinuity to derivativeness of the control law,so that the chatterings of control can be eliminated.

针对机器人跟踪控制问题，设计了一种新型的动态滑模控制器，采用反演方法设计一种新的切换函数，将不连续项转移到了控制的一阶导数中，得到了输入的平滑性的动态滑模控制律。

It will discuss the algorithm from three parts:(1) disparting theselected points;(2) how to find start point and end points first derivative (3) thealgorithm which forms the curve.

本文将主要从3个方面进行论述这一算法：(1)对选定点的纵横划分；(2)划分后端点一阶导数的确定方法；(3)形成曲线的数值方法。

Magnetotelluric field finite difference migration tomography Found on the researches of Zhdanov etc. in MT finite difference migration tomography, we analyze and summarize both fruits and limitation of foregone peoples' achievements. So more precise finite difference extrapolation equation can be deduced, and it can be easily applied into the migration tomography. New equation reserved the derivative terms of wave number both at vertical and horizontal direction, so that more exquisite geoelectric diversification can still be accommodated, that is the very requirement of practical data interpolation.

大地电磁有限差分偏移成像技术：在Zhdanov等人建立的有限差分偏移成像研究的基础上，总结分析了前人在 MT成像技术方面的研究成果和存在问题；推导更精确的有限差分波场延拓方程，采用改进的有限差分法进行大地电磁场偏移成像，差分延拓方程保留波数对水平方向和垂直方向的一阶导数项而提高求解精度，可适应电性纵横方向变化剧烈的地电构造，使成像分辨率得到增强。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。