Low dispersion turns and junctions for microchannel systems
Low dispersion turns and junctions for microchannel systems
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DOI：
10.1021/ac000936q
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发表时间：
2001-01-15
影响因子：
7.4
通讯作者：
Nilson, RH
中科院分区：
文献类型：
--
作者：
Griffiths, SK;Nilson, RH
采用数值方法对二维微通道回转的几何形状进行了优化，使得回转引起的溶质带扩展最小。首次提出了一种反演数值方法，用于计算任意几何形状下的电势和局域物种运动。然后，以物种分布的空间方差为目标函数，采用非线性最小二乘算法对转弯几何形状进行优化。这种方法产生的转弯几何图形产生最小可能的离散度，仅受规定约束的约束。由此产生的低离散度回转提供了比可比的常规回转低2-3个数量级的诱导变化。给出了180度和90度旋转的示例结果，并讨论了使用这些旋转来形成Y形三通和T形三通。提供了一个45度Y形三通的样本。还讨论了低分散转弯在折叠分离柱中的应用，并给出了将宽100微米、长达900 mm的柱折叠到仅10×10 mm的区域的示例计算。这些低分散几何结构适用于电渗透、电泳法和某些压力驱动流。
Numerical methods are employed to optimize the geometry of two-dimensional microchannel turns such that the turn-induced spreading of a solute band is minimized. An inverted numerical method is first developed to compute the electric potential and local species motion in turns of arbitrary geometry. The turn geometry is then optimized by means of a nonlinear least-squares minimization algorithm using the spatial variance of the species distribution leaving the turn as the object function. This approach yields the turn geometry producing the minimum possible dispersion, subject only to prescribed constraints. The resulting low-dispersion turns provide an induced variance 2-3 orders of magnitude below that of a comparable conventional turns. Sample results are presented for 180 and 90 degrees turns, and the use of these turns to form wyes and tees is discussed. A sample 45 degrees wye is presented. The use of low-dispersion turns in folding separation columns is also discussed, and sample calculations are presented for folding a column 100 mum in width and up to 900 mm in length onto a region of only 10 by 10 mm. These low-dispersion geometries are applicable to electroosmosis, electrophoresis, and some pressure-driven flows.