1) second difference of direction angle
方向二阶差分
2) second order difference equation
二阶差分方程
1.
New oscillation criteria are presented in this paper for nonlinear second order difference equations:Δ2bun+∑mi=1ainfi(un,Δbun)=0, n=0,1,2,…
对非线性二阶差分方程Δ２ｂｕｎ＋∑ｍｉ＝１ａｉｎｆｉ（ｕｎ，Δｂｕｎ）＝０，ｎ＝０，１，２，…给出并证明了它的有界解振动的新充分判则。
2.
Oscillation criteria for nonlinear second order difference equations are established,Results obtained improve theorems in the literature[5].
本文建立了非线性二阶差分方程的若干振动准则，所得结果改进了文［５］中相应的定理。
4) Difference in Difference Approach
二阶差分方法
5) directional second derivative
方向性二阶微分
1.
Based on the simulated data produced by PROSAIL model and field test data, the authors respectively analyzed many kinds of factors which affect some representative inversion methods, such as VI, second derivative, model inversion and the directional second derivative.
以PROSAIL模型模拟数据和地面实测数据为基础,分别分析了土壤背景、冠层反射率非各向同性以及随机噪声等因素对几类代表性反演方法的影响(植被指数法、二阶微分法、模型反演法以及方向性二阶微分法)。
6) second difference
二阶差分
1.
Phase unwrapping algorithm based on minimum second difference;
基于最小二阶差分的相展开方法
2.
Weighted minimum cost flow phase unwrapping algorithm based on second difference;
基于二阶差分的加权最小费用流相位展开算法
补充资料：对称差分(n阶的)
对称差分(n阶的)
symmetric difference of order
对称差分(n阶的)l另11111州tric山ffer曰℃eof份der‘c“MMe邓一，ecK即pa3Hoc几“op，皿Kan」，一元实变函数f在点x上的 表达式 声/n、，.、。，/.n一Zk八 △口ffx，h)=)l:’1(一1)“f lx十二二~一竺二生h 1. 一‘““一””k饥戈k/、‘产“戈一2‘’/‘将h换成Zh，下面的表达式也称为对称差分: 息川(一1)*，‘二+、。一2、)。).假若f(x)在x有n阶导数厂时(x)，那么 △二f(x，h)=./戈n)(x)h”+o(h”). T .fl .J’IyKame皿。撰
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参考词条