多纤芯弹性光网络中虚拟网络映射模型及算法

为解决多纤芯弹性光网络虚拟化中的虚拟结点映射、链路映射和频谱分配问题,首先建立了一个以最小化占用的频谱数及最小化最大占用频隙号为目标的全局约束优化模型.其次,设计了具有高效的交叉、变异及不可行解可行化算子的全局优化遗传算法,以有效求解该模型得到最优的虚拟节点、链路映射方案.最后,为验证算法的有效性进行了不同的仿真实验.结果表明,所设计的算法能够有效地减小网络中占用的频谱数和最大占用频隙号.     

一个典型弹性梁方程涉及第一特征值的正解

运用锥理论和不动点指数方法,在与相应的线性算子第一特征值有关的条件下,获得了一个典型弹性梁方程正解的存在性,改进了相关文献的结论.     

2020年细胞力学热点回眸

 概述了2020年细胞力学研究的热点和进展，探讨了细胞膜表面张力、细胞粘附力、细胞弹性模量、细胞与纳米颗粒相对刚度等对细胞生物学行为的影响及其在疾病诊疗中的应用。     

Short‐term salmon price forecasting

This study establishes a benchmark for short‐term salmon price forecasting. The weekly spot price of Norwegian farmed Atlantic salmon is predicted 1–5 weeks ahead using data from 2007 to 2014. Sixteen alternative forecasting methods are considered, ranging from classical time series models to customized machine learning techniques to salmon futures prices. The best predictions are delivered by k‐nearest neighbors method for 1 week ahead; vector error correction model estimated using elastic net regularization for 2 and 3 weeks ahead; and futures prices for 4 and 5 weeks ahead. While the nominal gains in forecast accuracy over a naïve benchmark are small, the economic value of the forecasts is considerable. Using a simple trading strategy for timing the sales based on price forecasts could increase the net profit of a salmon farmer by around 7%.     

波动方程在半无穷柱体和外部区域上的空间爆破和衰减性

利用能量分析的方法, 首先考虑定义在三维半无穷柱体上的波动方程, 当空间变量趋于无穷时, 证明其解或者指数式增长或者指数式衰减; 其次, 考虑定义在球面外部区域上的波动方程, 证明其解随半径的二择一结果； 最后, 证明对于非线性弹性方程, 二择性定理仍有效.     

非线性弹性杆波动方程的精确解

通过假设2个非线性弹性杆波动方程的行波解,得到其常微分方程,运用Exp函数法,并借助Mathematica软件,获得了这2个非线性弹性杆波动方程的精确解.     

Propagation patterns of microseismic waves in rock strata during mining: an experimental study

Microseismic monitoring has been widely used in mines for monitoring and predicting dynamic disasters such as rockbursts and waterbursts. However, to develop high-precision microseismic monitoring systems, the propagation patterns of microseismic waves under complex geological conditions must be elucidated. To achieve this aim, a simulation model of a typical coalmine was designed using similar materials according to the similarity theory to simulate the mining process. Geophones were embedded into the model to detect the propagation of elastic waves from microseisms. The results show that in an unmined solid rock mass, the wave velocity in shallow rock strata is mainly affected by geologically weak planes, whereas in deep strata it is affected mainly by the density of the rock mass. During propagation, the amplitude first decreases and then increases rapidly with increasing propagation distance from the coal layer. After mining, our results indicate that the goaf causes significant attenuation of the wave velocity. After the goaf was backfilled, the velocity attenuation is reduced to some extent but not eliminated. The results of this study can be used as guidelines for designing and applying microseismic monitoring systems in mines.     

考虑弹性支承和剪切变形影响的单跨斜梁温度次内力分析

在考虑端横梁弯曲和支座变形对斜主梁提供的弹性抗扭支承和竖向弹性支承以及斜主梁剪切变形的基础上,导出了考虑支承刚度以及剪切变形影响的单跨斜梁温度次内力的计算公式,并通过一个简单算例对公式进行了验证,分析了支承刚度、斜度以及剪切变形对斜主梁温度次内力的影响。研究结果表明,在一定范围内,端横梁抗弯刚度的变化会引起斜梁温度次内力的急剧变化;斜主梁的温度次内力可以通过改变端横梁的抗弯刚度进行有效的调整;当斜度等于0°时,剪切变形对次扭矩的影响达到最大,为10.6%。     

基于核Fisher判别的致密碎屑岩岩性识别

致密碎屑岩储层具有致密、低孔隙和非均质性强等特点,岩性识别是储层预测中的难点之一。文章针对这一问题,提出将核Fisher判别方法用于致密碎屑岩储层的岩性识别,结果表明核Fisher判别方法能有效的识别川西XC地区致密碎屑岩中的砂岩和粉砂岩。     

双E型六维力传感器矩形梁强迫振动分析

六维力传感器弹性体一般采用组合梁结构,每个分方向的输出信号中不可避免地存其它分方向的受力信号的耦合输出。在动载工作条件下,六维力传感器动态耦合输出非常复杂。为了从理论上揭示六维力传感器动态耦合输出的主要特征,本文以双E型六维力传感器中的矩形梁为对象,建立力学模型,采用弹性力学基本理论和达朗贝尔原理,选取矩形梁前三阶振型,推导出其它五个分方向受力在Mz主方向的动态耦合输出,并绘制出动态应变图,为六维力传感器动态解耦提供了理论依据。