Supply China Production-distribution Cost Optimization under Grey Fuzzy Uncertainty

Most supply chain programming problems are restricted to the deterministic situations or stochastic environments. Considering twofold uncertainty combining grey and fuzzy factors, this paper proposes a hybrid uncertain programming model to optimize the supply chain production-distribution cost. The programming parameters of the material suppliers, manufacturer, distribution centers, and the customers are integrated into the presented model. On the basis of the chance measure and the credibility of grey fuzzy variable, the grey fuzzy simulation methodology was proposed to generate input-output data for the uncertain functions. The designed neural network can expedite the simulation process after trained from the generated input-output data. The improved Particle Swarm Optimization (PSO) algorithm based on the Differential Evolution (DE) algorithm can optimize the uncertain programming problems. A numerical example was presented to highlight the significance of the uncertain model and the feasibility of the solution strategy.     

Do female hyaenas choose mates based on tenure?

In their investigation into whether female mate-choice drives male dispersal, H?ner et al. argue that female spotted hyaenas (Crocuta crocuta) prefer mates whose tenure in the social group is less than the females' age, to avoid paternal incest, and suggest that male dispersal reflects this preference. However, we are not persuaded that females choose mates on the basis of tenure because H?ner et al. overlook the alternative hypothesis that dispersal status itself is important in female mate-choice, such that females prefer immigrants over natal males. Like mate-choice based on tenure, choice based on dispersal status reduces the risk of incest.     

Semi-annual oscillations in Saturn's low-latitude stratospheric temperatures

Observations of oscillations of temperature and wind in planetary atmospheres provide a means of generalizing models for atmospheric dynamics in a diverse set of planets in the Solar System and elsewhere. An equatorial oscillation similar to one in the Earth's atmosphere has been discovered in Jupiter. Here we report the existence of similar oscillations in Saturn's atmosphere, from an analysis of over two decades of spatially resolved observations of its 7.8-microm methane and 12.2-microm ethane stratospheric emissions, where we compare zonal-mean stratospheric brightness temperatures at planetographic latitudes of 3.6 degrees and 15.5 degrees in both the northern and the southern hemispheres. These results support the interpretation of vertical and meridional variability of temperatures in Saturn's stratosphere as a manifestation of a wave phenomenon similar to that on the Earth and in Jupiter. The period of this oscillation is 14.8 +/- 1.2 terrestrial years, roughly half of Saturn's year, suggesting the influence of seasonal forcing, as is the case with the Earth's semi-annual oscillation.     

灰色评价指标的一种曲率可调非线性标准化转换方法

针对绩效评价体系中评价指标属性值为灰数的情形,分别为成本型、效益型、适中型评价指标设计了曲率可调非线性标准化转换方法,把灰色评价指标的属性值转换到[0,1]的标准化区间,不同量纲和不同范围的灰色评价指标可以在转换后的标准化区间内相互比较。设计的上凸型和下凹型转换曲线分别表达了对评价指标的严格和宽松的评价要求。给出了曲率调整系数α的选择原则,通过调整α,可以非线性地改变成本型、效益型、适中型评价指标随目标函数的变化趋势。以某电子公司绩效评价指标为例说明了灰色评价指标的非线性标准化转换方法。     

一类具偏差变元的二阶微分方程周期解

利用Mahwin重合度理论研究了一类具偏变元的二阶微分方程的T-周期解问题,得到了周期解存在若干新的结果,并推广了已有的结果.     

铁道车辆几何滤波现象及弹性车体共振分析

运用简化铁道车辆模型,对几何滤波现象进行了分析.建立了刚柔耦合弹性车体模型,分析了几何滤波现象对车体响应功率谱的影响,以及几何滤波与弹性车体共振频率的关系.研究表明,几何滤波分为轴距滤波和定距滤波.在某些特定轨道不平顺波长下,车体的点头和浮沉响应均为零,该现象称为轴距滤波;定距滤波是指在某些波长下,车体的浮沉或者点头响应为零.在车体空点头响应频率附近,轨道对车体浮沉振动的加速度传递率达到局部最大,当车体的垂向1阶弯曲频率与这些峰值频率吻合时,将产生车体弹性共振现象.     

模糊-PI双模控制与模糊控制的仿真比较

典型的二维模糊控制器因缺少积分环节,难以消除稳态误差,因此控制的精度常常不能满足系统要求.而PI控制器具有良好的消除稳态误差的作用,所以通常将其与模糊控制器结合构成复合控制器.模糊-PI控制的结构多种多样,选取其中的一种--双模控制,通过在MATLAB/Simulink中建立其模型,对其进行了大量的仿真,将其结果与相同条件下典型模糊控制的仿真结果进行比较,得出双模控制在消除稳态误差方面优于模糊控制,并在参数选取方面得出了一定的结论.     

脉冲电流法电解精炼铜的可行性研究

文章介绍实验模拟铜电解精炼的工业生产条件 ,在小型电解槽中研究脉冲电流法电解精炼铜的可行性 ,并用 XRD、SEM及等离子体质谱仪研究杂质对阴极铜沉积的结构和组成的影响。研究表明 ,当电解温度为 6 0℃时 ,脉冲电解较适宜的工艺条件为 :峰电流密度 396 0 A/ m2 ,脉冲宽度 0 .5 m s,脉冲频率 333Hz,占空比 1∶ 5。添加剂用量 :Cl-3.0 m g/ dm3 ,( N H2 ) 2 CS 0 .75～ 1.0 mg/ dm3 ,glue 1.0～ 1.5 m g/ dm3 。电解液中有害杂质容许量 :As5+ ≤ 2 .0 g/ dm3 ,Sb3 + ≤ 0 .2 0 g/ dm3 ,Bi3 + ≤ 0 .10 g/ dm3。测试结果表明 ,当电解液中不含杂质时 ,铜沉积的晶面择优取向为 ( 2 0 0 ) ,结晶形态为层状 ;电解液中含杂质时 ,铜沉积的晶面择优取向为 ( 2 2 0 ) ,结晶形态为层状 +块状。     

异重射流流动形态和浓度分布特性的实验研究

对横向抛射入环境水流中形成的导射流的流动形态及浓度分布特征进行了水槽实验研究。实验结果表明异重射流入水后在近区呈现出不同于一般变密度射流的复杂流动形态及浓度分布特征,并以异重流的形式向下游推移。