结构

Abstract(#br)A microfluidic device containing a constructal-based branched flow structure with an externally controllable complexity was developed and tested in this study. The device was fabricated in the form of a 10\u003cce:hsp sp=\"0.25\"/\u003emm square by 9\u003cce:hsp sp=\"0.25\"/\u003emm high monolithic silicon/polydimethylsiloxane (PDMS) test section which contains three interconnected flow channels in a tee configuration.

The goal of this study was to create polydimethylsiloxane (PDMS) and microcrystalline cellulose (MCC) composites with high mechanical properties and antimicrobial activity. Vinyl-terminated PDMS was mixed with bifunctional filler, which combines MCC stiffness and antimicrobial properties of silver nanoparticles. To provide antimicrobial properties the silver nanoparticles in situ were synthesized by chemical reducing method in MCC aqueous suspension. Silver nanoparticles (AgNPs) concentration deposited on MCC particles surface was varied.

Abstract(#br)Oil in water Pickering emulsions undergoing catastrophic phase inversion were investigated. Two polydimethylsiloxane (PDMS) oils of various viscosity have been emulsified in water and stabilized with fumed silica particles. The concentration of particles and the oil volume fraction were varied from 0.1 to 1 wt% and from 10 to 90 vol%, respectively. Upon increasing the oil content, a phase inversion occurred from oil-in-water to water-in-oil as evidenced from macroscopic and microscopic observations.

对软脆聚二甲基硅氧烷( PDMS )基弹性体的断裂和能强度标度进行了研究。用两种PDMS弹性体对不同尺寸的预裂纹试样进行了Ⅰ型拉伸断裂试验，其刚度、强度和韧性均有明显的变化。该结果是在现有的含能Ⅱ型Bazant尺寸效应定律( SEL )框架内解释的。SEL被发现适用于PDMS弹性体，尽管它的非线性应力应变行为。这是因为非线性相当弱，使得应变能近似与名义应力的平方成正比，类似于线弹性材料。研究发现，在实验室尺度下，两种弹性体的结构强度均与试件尺寸呈自相似的规律，落在SEL的大尺寸渐近线上，然后利用黏聚性裂纹模型对较小试件的强度进行数值预测。对于这两种弹性体来说，这些强度在SEL的过渡性部分正方形下降，意味着不完全的自相似性和向准脆性断裂的过渡。这是由于断裂过程区的主导性增加，其大小由各种方法估算。说明如果不考虑这种转变，对于较小的尺寸，结构强度可以超预期140 %甚至更高。因此，首次证明了软弹性体，如果是弱非线性的，符合能量Ⅱ型强度标度律。