胶含量、pH值及电解质对Mg-Fe-HTlc/高岭土分散体系流变性的影响

胶含量、pH值及电解质对Mg-Fe-HTlc/高岭土分散体系流变性的影响;类水滑石化合物;高岭土;剪切应力;分散体系;流变性     

弹性动脉血管中血液流动特性的模拟和分析

研究了两个不同的非牛顿血液流动模型:低粘性剪切简单幂律模型和低粘性剪切及粘弹性振荡流的广义Maxwell模型．同时利用这两个非牛顿模型和牛顿模型,研究了磁场中刚性和弹性直血管中血液的正弦型脉动．在生理学条件下,大动脉中血液的弹性对其流动性态似乎并不产生影响,单纯低粘性剪切模型可以逼真地模拟这种血液流动．利用高剪切幂律模型模拟弹性血管中的正弦型脉动流,发现在同一压力梯度下,与牛顿流体相比较,幂律流体的平均流率和流率变化幅度都更小．控制方程用Crank-Niclson方法求解．弹性动脉中血液受磁场作用是产生此结果的直观原因．在主动脉生物流的模拟中,与牛顿流体模型比较,发现在匹配流率曲线上,幂律模型的平均壁面剪切应力增大,峰值壁面剪切应力减小．讨论了弹性血管横切磁场时的血液流动,评估了血管形状和表面不规则等因素的影响．     

分析磁流变流体屈服应力微观力学模型

剪切屈服应力是磁流变流体固化强度的重要指标之一,具有重要的工程意义。基于磁性物理学理论,从磁流变流体在磁场作用下铁磁性固体颗粒极化成链的微观结构出发,探讨磁流变流体中固体颗粒间的相互作用机理,分析研究颗粒间的相互作用力,建立了一种微观力学模型,可用于分析磁流变流体在外加磁场作用下屈服应力及其影响因素的作用效果,揭示磁流变效应的微结构机理,为磁流变流体的性能优化、工程开发及应用磁流变流体提供理论依据。     

Further investigations on the influence of scale-up of a high shear granulator on the granule properties

This study focuses on the characterisation of strength, density, and size of granules produced in various scales of a high shear granulator. Calcium carbonate （Durca165） was used as the feed powder and aqueous polyethylene glycol （PEG 4000） as the binder. The dried granules were analysed for their strength, density, size distribution, and wall make-up. Granules were produced in granulators with four scales, 1, 5, 50, and 250 L under three scale-up rules of constant tip speed, constant shear stress, and constant Froude number. The results show that regardless of equipment scale, increasing the impeller speed has a great effect on crushing strength and stress. The underlying cause is an increase in granule density due to more consolidation at higher impeller speeds. Wall make-up is significantly reduced to less than 5% as the scale is increased from 1 to 250 L. The results of this study corroborate our previous findings that the constant tip speed rule is the best criterion for scale-up of high shear granulators.     

聚氨酯泡沫塑料动态剪切力学行为的研究

通过大型精密分段式Ｈｏｐｋｉｎｓｏｎ 扭杆实验装置对聚氨酯泡沫塑料进行了动态扭转实验,研究了聚氨酯泡沫塑料在剪切应力波加载下的力学行为,得到了这类材料的动态剪切应力 应变曲线和动态力学性能参数。此外,针对动态扭转破坏试件断口进行了扫描电镜分析,研究了泡沫塑料动态剪切破坏的机制。还给出了同准静态扭转实验结果的比较。     

采用液晶涂层测量介质流与壁面间剪切应力的定量模型与试验研究

流场中介质流与壁面间剪切应力的定量测量,在运动物体例如航天器等的表面流场观测与表面减阻等领域有重要意义.本文采用向列相液晶涂层技术针对介质流与固体壁面间的剪切应力展开定量测量.首先利用液晶弹性变形理论建立了向列相分子在剪切应力场作用下旋光性光强信号与剪切应力大小的定量模型;进而,在固体表面制备了5 CB与7 CB向列相液晶涂层,采用搭建的实验装置对不同剪切应力场下的测试涂层的光强进行了测试与理论模型的计算模拟,测试结果与定量模型相当吻合;进一步探讨了液晶涂层测试技术的极限剪切应力、灵敏范围以及涂层膜厚、分子弹性等关键影响因素.     

TORSIONAL VIBRATIONS OF A RIGID CIRCULAR PLATE ON SATURATED STRATUM OVERLAYING BEDROCK

The torsional vibration of a rigid plate resting on saturated stratum overlaying bedrock has been analysed for the first time. The dynamic governing differential equations for saturated poroelastic medium are solved by employing the technology of Hankel transform. By taking into account the boundary conditions, the dual integral equations of torsional vibration of a rigid circular plate are established, which are further converted into a Fredholm integral equation of the second kind. Subsequently, the dynamic compliance coefficients of the foundation on saturated stratum, the contact shear stress under the foundation and the angular amplitude of the foundation are evaluated. Numerical results indicate that, when the dimensionless height is bigger than 5, saturated stratum overlaying bedrock can be treated as saturated half space approximately. When the dimensionless frequency is low, the permeability of the soil must be taken into account. Furthermore, when the vibration frequency is a constant, the height of the saturated stratum has a slight effect on the dimensionless contact shear stress under the foundation.     

研究大分子溶液流变性质的核磁共振成象实验装置

在Bruker MSL-400微成象谱仪上建立了一个研究大分子溶液流变性质的核磁共振成象的装置.此方法取决于两个方面:1)具有一个能产生稳态流动的Couete cell装置,2)使用能得到正常核磁共振流速象的脉冲序列.从成象数据很易得到剪切应力与剪切速度的关系.     

在法向应力影响下岩质材料的非线性粘塑性蠕变属性

1 引言文献[2]在S S Vyalov 的研究基础上,进一步改进和完善了Vyalov 的研究假设,分别提出了在纯剪和单轴压缩条件下的岩质材料非线性蠕变模型,但是,未曾进行复杂应力状态下的非线性蠕变性态的研究.因此,本文将在此基础上,对岩质材料非线性剪切蠕变性态进行深入的研究,进一步考虑最大剪应力面上的法向应力对岩质材料非线性粘塑性剪切蠕变的影响,提出了反映法向应力影响的岩质材料非线性粘塑性剪切蠕变的力学模型和蠕变方程,并给出了在一定的法向应力和剪切应力下,岩质材料发生衰减蠕变、线性蠕变和加速蠕变变形所需满足的条件.     

横观各向同性板的分解理论

将分解理论从各向同性板推广至横观各向同性板,得到横观各向同性板的分解理论,即横观各向同性板 内应力状态可以分解成内应力状态、剪切应力状态和超越应力状态,并给出严格的数学证明.