摘要翻译：
剪切变稀是许多生物流体（如粘液）的一个重要流变特性，即流体的表观粘度随剪切而减小。某些微观游泳者已经被证明在剪切变稀流体中进步更快，但这种行为是否对所有微观游泳者都是通用的？剪切变稀流变学通过什么物理来影响游泳者的推进力？我们在二维、无惯性的卡罗流体：剪切减薄的“广义斯托克斯”流中使用规定的划水运动学来检查游泳者。游泳者的模型，使用女性的方法，由一组浸入，规则的力量。然后，控制流体动力学的方程在贴体网格上离散，并用有限元法求解。我们分析了三种不同类别的微泳者的运动：（1）概念泳者包括使用一维和二维划水的滑动球体；（2）通常被称为“蠕动者”的纤毛虫的滑动速度包络模型；（3）单鞭毛推进者，如精子。我们发现，形态上相同的游泳者在剪切变稀流体中比在牛顿流体中游得更快或更慢。我们通过考虑游动器推进元件和有效载荷元件周围流体粘度的差异来解释这种运动学敏感性，并利用这种观点提出了两种在剪切变稀流体中违反Purcell扇贝定理的倒易滑动球形游动器。我们还表明，由剪切变稀流变引起的流动衰减速率的增加与滑移速度蠕动器游动速度的减小有关。对于类似精子的游泳者来说，沿着鞭毛从浓到稀的液体梯度改变了它对液体施加的力，使运动轨迹变平，并增加了瞬时游泳速度。
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英文标题：
《Physics of Rheologically-Enhanced Propulsion: Different Strokes in
  Generalized Stokes》
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作者：
Thomas D. Montenegro-Johnson, Daniel Loghin and David J. Smith
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最新提交年份：
2013
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分类信息：

一级分类：Physics        物理学
二级分类：Fluid Dynamics        流体动力学
分类描述：Turbulence, instabilities, incompressible/compressible flows, reacting flows. Aero/hydrodynamics, fluid-structure interactions, acoustics. Biological fluid dynamics, micro/nanofluidics, interfacial phenomena. Complex fluids, suspensions and granular flows, porous media flows. Geophysical flows, thermoconvective and stratified flows. Mathematical and computational methods for fluid dynamics, fluid flow models, experimental techniques.
湍流，不稳定性，不可压缩/可压缩流，反应流。气动/流体力学，流体-结构相互作用，声学。生物流体力学，微/纳米流体力学，界面现象。复杂流体，悬浮液和颗粒流，多孔介质流。地球物理流，热对流和层流。流体动力学的数学和计算方法，流体流动模型，实验技术。
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一级分类：Physics        物理学
二级分类：Soft Condensed Matter        软凝聚态物质
分类描述：Membranes, polymers, liquid crystals, glasses, colloids, granular matter
膜，聚合物，液晶，玻璃，胶体，颗粒物质
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一级分类：Physics        物理学
二级分类：Biological Physics        生物物理学
分类描述：Molecular biophysics, cellular biophysics, neurological biophysics, membrane biophysics, single-molecule biophysics, ecological biophysics, quantum phenomena in biological systems (quantum biophysics), theoretical biophysics, molecular dynamics/modeling and simulation, game theory, biomechanics, bioinformatics, microorganisms, virology, evolution, biophysical methods.
分子生物物理、细胞生物物理、神经生物物理、膜生物物理、单分子生物物理、生态生物物理、生物系统中的量子现象（量子生物物理）、理论生物物理、分子动力学/建模与模拟、博弈论、生物力学、生物信息学、微生物、病毒学、进化论、生物物理方法。
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一级分类：Quantitative Biology        数量生物学
二级分类：Other Quantitative Biology        其他定量生物学
分类描述：Work in quantitative biology that does not fit into the other q-bio classifications
不适合其他q-bio分类的定量生物学工作
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英文摘要：
  Shear-thinning is an important rheological property of many biological fluids, such as mucus, whereby the apparent viscosity of the fluid decreases with shear. Certain microscopic swimmers have been shown to progress more rapidly through shear-thinning fluids, but is this behavior generic to all microscopic swimmers, and what are the physics through which shear-thinning rheology affects a swimmer's propulsion? We examine swimmers employing prescribed stroke kinematics in two-dimensional, inertialess Carreau fluid: shear-thinning "Generalized Stokes" flow. Swimmers are modeled, using the method of femlets, by a set of immersed, regularized forces. The equations governing the fluid dynamics are then discretized over a body-fitted mesh and solved with the finite element method. We analyze the locomotion of three distinct classes of microswimmer: (1) conceptual swimmers comprising sliding spheres employing both one- and two-dimensional strokes, (2) slip-velocity envelope models of ciliates commonly referred to as "squirmers" and (3) monoflagellate pushers, such as sperm. We find that morphologically identical swimmers with different strokes may swim either faster or slower in shear-thinning fluids than in Newtonian fluids. We explain this kinematic sensitivity by considering differences in the viscosity of the fluid surrounding propulsive and payload elements of the swimmer, and using this insight suggest two reciprocal sliding sphere swimmers which violate Purcell's Scallop theorem in shear-thinning fluids. We also show that an increased flow decay rate arising from shear-thinning rheology is associated with a reduction in the swimming speed of slip-velocity squirmers. For sperm-like swimmers, a gradient of thick to thin fluid along the flagellum alters the force it exerts upon the fluid, flattening trajectories and increasing instantaneous swimming speed.
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PDF链接：
https://arxiv.org/pdf/1309.1076