二维网格结构的拟膜分析法

分析了具有正交对角型单胞的平面网格结构。将其比拟为平面膜结构,并求出膜的面内刚度参数。给出平面网格结构嵌入各向同性基体材料而成的复合材料板的弹性本构参数表达式,并用数值方法简单验证了复合材料弹性本构参数表达式的正确性。     

R0-代数与MV-代数的关系

证明了剩余格和正则剩余格中一些典型的附加条件之间的等价性,引入了正规剩余格的概念并给出了其若干性质。以此为基础,讨论了R0-代数和MV-代数之间的关系。     

非饱和土壤一维水分入渗与再分布的解析解法

Soil infiltration and redistribution are important processes in field water cycle, and it is necessary to develop a simple model to describe the processes. In this study, an algebraic solution for one-dimensional water infiltration and redistribution without evaporation in unsaturated soil was developed based on Richards equation. The algebraic solution had three parameters, namely, the saturated water conductivity, the comprehensive shape coefflcient of the soil water content distribution, and the soil suction allocation coefficient. To analyze the physical features of these parameters, a relationship between the Green-Ampt model and the algebraic solution was established. The three parameters were estimated based on experimental observations, whereas the soil water content and the water infiltration duration were calculated using the algebraic solution. The calculated soil water content and infiltration duration were compared with the experimental observations, and the results indicated that the algebraic solution accurately described the unsaturated soil water flow processes.     

现浇钢筋混凝土格构锚固结构研究应用现状及展望

从现浇钢筋混凝土格构锚固结构的布置形式、对边坡加固的机理以及结构的计算方法几个方面介绍了该结构的研究和应用的现状,并在此基础上对今后该种结构的研究方向做出展望。     

A reduced growth model based on stand basal area. A case for hybrid poplar plantations in northeast Spain

Whole-stand models normally require data on initial stand basal area and dominant height. Dominant height measurements are time-consuming and often imprecise, compromising subsequent predictions. Poplar plantations provide a special case where basal area correlates with site index; a whole-stand model could thus be based on stand basal area. We report a static model constructed by the generalized algebraic difference approach (GADA) for poplar plantations for three different hybrid poplars (Populus × euramericana (Dode) Guinier “I-214”, “MC”, and “Luisa Avanzo”) in northeast Spain. The transition function was based on current stand basal area and was fitted with data from 158 permanent plots ranging from 1- to 17-year-old plantations. Merchantable stand volume was estimated by a volume equation where height was predicted by a height–basal area relationship based on 458 temporary plots. The model differences between clones were compared using the nonlinear extra sum of squares method. Significant differences were detected, while Luisa Avanzo presented the highest merchantable volume at the end of the rotation. Errors in basal area predictions were below 20% within 6 years in the case of Luisa Avanzo and MC clones, and within 3 years in the case of I-214. Our research showed that satisfactory predictions can be obtained using GADA with a single transition function based on an easily measurable variable such as stand basal area.     

反应网络的物料平衡一致性校验

通过对反应网络的物料平衡分析，提出了反应网络的物料平衡一致性校验方程，并用于反应网络的数据校正和推测     

行列式定义间的等价性及某些性质的证明

给出行列式两种定义的等价性，并且由第二种定义证明了行列式的一些性质．     

基于格子Boltzmann方法的可压缩翼型绕流模拟

采用能够恢复可压缩Navier-Stokes方程的耦合双分布(DDF)格子Boltzmann方法(LBM)模拟了贴体网格下的NACA0012翼型绕流.首先在Ma＝0.5,α＝0.0,Re＝5 000状态下通过模拟低雷诺数流动检验了该方法;然后分别在Ma＝0.5,0.85和1.2,α＝-0.05,1.0和0.0状态下进行了模拟,并在Ma＝0.85时通过加密网格得到了更好的结果.为了避免转捩问题采用了无粘边界条件进行模拟,但得到的压力系数与实验结果吻合良好,证明了该方法的可靠性并显示了其模拟可压缩的潜力.该方法在翼型绕流上的应用为湍流流动的数值模拟提供了基础.     

3D格子Boltzmann传质模型模拟生物膜降解有机污水

以膜生物法有机污水处理为研究背景,将3D格子Boltzmann传质模型与多孔介质四参数随机生成法耦合,获得生物膜多孔介质详细的孔隙分布,进而对反应器内生化降解反应过程进行模拟计算。研究分析了生物膜孔隙率及孔隙分布对流动传质及生化反应性能的影响,并与试验结果比较证明了模型的可行性。结果表明:各方向生长概率p1-14=0.005,随着生物膜孔隙率增大,反应器内底物降解效率先增大后减小,且在孔隙率ε=0.5时达到最大,50.97%;孔隙率ε=0.5时,改变各方向生长概率重构获得5种不同结构生物膜,其降解效率随之改变,生物膜为结构1(p_(3-4)=0.01,p_(1,2,5-14)=0.005)时,底物降解效率最高,52.54%。因此,3D格子Boltzmann传质模型可用于膜生物反应器内的流动传质及生化反应过程的模拟,研究结果将对反应器的优化具有一定的指导作用。