Name: assembly and characterization of an external driver for the generation of sub-kilohertz oscillatory flow in microchannels
Uploaded: 2022-01-28T13:00:00
Description: Watch this Scientific Journal Video about Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels at JoVE.com

我们要感谢伊利诺伊大学机械科学与工程系快速成型实验室为这项工作提供的支持和提供的设施。

1. 快速原型模具设计与制造
<ol><li>在 PC 上打开 AutoCAD。在任务栏上选择“文件”，然后选择“ 打开 ”并浏览并单击具有.dxf或.dwg扩展名的通道模具的三维 （3D） 模型文件。</li>
	<li>通过单击并拖动整个模型周围的框来选择整个模型。通过将设计导出为 .stl 文件，方法是选择“ 文件| 导出，然后选择 其他格式 ，然后从下拉框中选择...

<ol>
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N., Usefian, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Active+and+passive+micromixers:+A+comprehensive+review.">Active and passive micromixers: A comprehensive review.</a> Chemical Engineering and Processing - Process Intensification. 147, 10771 (2020).</li><li>Zhang, S., Wang, Y., Onck, P., den Toonder, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+concise+review+of+microfluidic+particle+manipulation+methods.">A concise review of microfluidic particle manipulation methods.</a> Microfluidics and Nanofluidics. 24, 24 (2020).</li><li>Bayareh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+updated+review+on+particle+separation+in+passive+microfluidic+devices.">An updated review on particle separation in passive microfluidic devices.</a> Chemical Engineering and Processing - Process Intensification. 153, 107984 (2020).</li><li>Wu, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustofluidic+separation+of+cells+and+particles.">Acoustofluidic separation of cells and particles.</a> Microsystems &amp; Nanoengineering. 5, 32 (2019).</li><li>Bhagat, A. A. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidics+for+cell+separation.">Microfluidics for cell separation.</a> Medical &amp; Biological Engineering &amp; Computing. 48 (10), 999-1014 (2010).</li><li>M&#228;ki, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+and+Experimental+Characterization+of+Pressure+Drop+in+Gravity-Driven+Microfluidic+Systems.">Modeling and Experimental Characterization of Pressure Drop in Gravity-Driven Microfluidic Systems.</a> ASME Journal of Fluids Engineering. 137 (2), 021105 (2015).</li><li>Safavieh, R., Juncker, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capillarics:+pre-programmed,+self-powered+microfluidic+circuits+built+from+capillary+elements.">Capillarics: pre-programmed, self-powered microfluidic circuits built from capillary elements.</a> Lab on a Chip. 13, 4180-4189 (2013).</li><li>Hossan, M. R., Dutta, D., Islam, N., Dutta, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review:+Electric+field+driven+pumping+in+microfluidic+device.">Review: Electric field driven pumping in microfluidic device.</a> Electrophoresis. 39 (5-6), 702-731 (2018).</li><li>Dincau, B., Dressaire, E., Sauret, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsatile+Flow+in+Microfluidic+Systems.">Pulsatile Flow in Microfluidic Systems.</a> Small. 16 (9), 1904032 (2020).</li><li>Thurgood, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tunable+Harmonic+Flow+Patterns+in+Microfluidic+Systems+through+Simple+Tube+Oscillation.">Tunable Harmonic Flow Patterns in Microfluidic Systems through Simple Tube Oscillation.</a> Small. 16 (43), 2003612 (2020).</li><li>Xia, H. M., Wu, J. W., Zheng, J. J., Zhang, J., Wang, Z. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonlinear+microfluidics:+device+physics,+functions,+and+applications.">Nonlinear microfluidics: device physics, functions, and applications.</a> Lab on a Chip. 21, 1241-1268 (2021).</li><li>Glasgow, I., Aubry, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancement+of+microfluidic+mixing+using+time+pulsing.">Enhancement of microfluidic mixing using time pulsing.</a> Lab on a Chip. 3 (2), 114-120 (2003).</li><li>Zhang, P., Bachman, H., Ozcelik, A., Huang, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustic+Microfluidics.">Acoustic Microfluidics.</a> Annual Review of Analytical Chemistry. 13, 17-43 (2020).</li><li>Lieu, V. H., House, T. A., Schwartz, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrodynamic+Tweezers:+Impact+of+Design+Geometry+on+Flow+and+Microparticle+Trapping.">Hydrodynamic Tweezers: Impact of Design Geometry on Flow and Microparticle Trapping.</a> Analytical Chemistry. 84 (4), 1963-1968 (2012).</li><li>Jain, R., Darling, R. B., Lutz, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frequency+characterization+of+flow+magnitude+and+phase+in+resonant+microfluidic+circuits.">Frequency characterization of flow magnitude and phase in resonant microfluidic circuits.</a> Analytical Methods. 9, 5425-5432 (2017).</li><li>Squires, T. M., Quake, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidics:+Fluid+physics+at+the+nanoliter+scale.">Microfluidics: Fluid physics at the nanoliter scale.</a> Reviews of Modern Physics. 77, 977 (2005).</li><li>Zhang, C., Guo, X., Brunet, P., Costalonga, M., Royon, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustic+streaming+near+a+sharp+structure+and+its+mixing+performance+characterization.">Acoustic streaming near a sharp structure and its mixing performance characterization.</a> Microfluidics and Nanofluidics. 23 (9), 104 (2019).</li><li>Abolhasani, M., Oskooei, A., Klinkova, A., Kumacheva, E., G&#252;nther, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shaken,+and+stirred:+oscillatory+segmented+flow+for+controlled+size-evolution+of+colloidal+nanomaterials.">Shaken, and stirred: oscillatory segmented flow for controlled size-evolution of colloidal nanomaterials.</a> Lab on a Chip. 14, 2309-2318 (2014).</li><li>Thameem, R., Rallabandi, B., Hilgenfeldt, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+inertial+particle+manipulation+in+oscillating+flows.">Fast inertial particle manipulation in oscillating flows.</a> Physical Review Fluids. 2 (5), 052001 (2017).</li><li>Vishwanathan, G., Juarez, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inertial+focusing+in+planar+pulsatile+flows.">Inertial focusing in planar pulsatile flows.</a> Journal of Fluid Mechanics. 921, 1 (2021).</li><li>Geschiere, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Slow+growth+of+the+Rayleigh-Plateau+instability+in+aqueous+two+phase+systems.">Slow growth of the Rayleigh-Plateau instability in aqueous two phase systems.</a> Biomicrofluidics. 6, 022007 (2012).</li><li>V&#225;zquez-Vergara, P., Torres Rojas, A. M., Guevara-Pantoja, P. E., Poir&#233;, E. C., Caballero-Robledo, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+flow+spectrometer.">Microfluidic flow spectrometer.</a> Journal of Micromechanics and Microengineering. 27, 077001 (2017).</li><li>Sauret, A., Shum, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forced+generation+of+simple+and+double+emulsions+in+all-aqueous+systems.">Forced generation of simple and double emulsions in all-aqueous systems.</a> Applied Physics Letters. 100, 154106 (2012).</li><li>Vishwanathan, G., Juarez, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Steady+streaming+viscometry+of+Newtonian+liquids+in+microfluidic+devices.">Steady streaming viscometry of Newtonian liquids in microfluidic devices.</a> Physics of Fluids. 31, 041701 (2019).</li><li>Vishwanathan, G., Juarez, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Steady+streaming+flows+in+viscoelastic+liquids.">Steady streaming flows in viscoelastic liquids.</a> Journal of Non-Newtonian Fluid Mechanics. 271, 104143 (2019).</li><li>Vishwanathan, G., Juarez, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+and+application+of+sub-kilohertz+oscillatory+flows+in+microchannels.">Generation and application of sub-kilohertz oscillatory flows in microchannels.</a> Microfluidics and Nanofluidics. 24, 69 (2020).</li></ol>

我们已经演示了基于扬声器的外部设备的组装（参见协议关键步骤3和4）和操作（参见协议关键步骤5和6），用于在微流体设备中产生频率范围为10至1000 Hz的振荡流。需要对悬浮示踪剂颗粒进行粒子跟踪，以确定谐波运动的保真度，并校准在工作频率范围内可实现的振荡幅度范围。给定音量设置的幅度-频率曲线主要取决于扬声器的特性，这些特性无法更改（参见 图3A，...

微通道中液体流速的精确控制对于芯片实验室应用至关重要，例如液滴生产和封装1，混合2，3以及悬浮颗粒的分拣和操作4，5，6，7。流量控制的主要方法是注射泵，它产生高度受控的稳定流量，分配固定体积的液体或固定的体积流量，通常仅限于完全单向流量。产生单向流动的替代策略包括使用重力头8、毛细管力9或电渗流10。可编程注射泵允许对流速和分配体积进行瞬态双向控制，但由于注射泵的机械惯性，响应时间限制在大于1 s。
由于流动物理学的质变，在较短的时间尺度上进行流量控制解锁了6，11，12，13，14，15个其他不可访问的可能性。利用这种可变流物理的最实用方法是通过声波或振荡流，其时间段从10-1-10-9 s或101 -109 Hz不等。该频率范围的较高端使用体声波（BAW;100 kHz-10 MHz）和表面声波（SAW;10 MHz-1 GHz）设备访问。在典型的BAW器件中，通过在键合压电体上施加电压信号来振动整个基板和流体柱。这可以实现相对较高的吞吐量，但也会导致在较高振幅下加热。然而，在SAW器件中，固液界面通过向压电基板上图案化的一对叉指电极施加电压来振荡。由于波长非常短（1 μm-100 μm），小至300 nm的颗粒可以通过SAW设备中产生的压力波精确地操纵。尽管能够操纵小颗粒，但SAW方法仅限于局部粒子操纵，因为波会随着与源的距离而迅速衰减。
在1-100 kHz频率范围内，振荡流通常使用压电元件产生，压电元件键合到设计腔体16，17上方的聚二甲基硅氧烷（PDMS）微通道上。图案化腔上方的PDMS膜的行为类似于振动膜或鼓，对通道内的流体加压。在此频率范围内，波长大于通道尺寸，但振荡速度幅度较小。在这种频率状态下，最有用的现象是产生声波/粘性流，这些流是由于惯性为18的液体流动中固有的非线性而引起的整流稳定流。稳定的流动通常表现为障碍物，尖角或微气泡附近的高速反向旋转涡流。这些涡旋可用于混合19，20 并从流流21中分离10μm大小的颗粒。
对于10-1000 Hz范围内的频率，振荡分量的速度及其相关的稳定粘性流在幅度和有用性方面都是相当大的。该频率范围内的强振荡流可用于惯性聚焦22，促进液滴23的产生，并且可以产生模拟血流的流动条件（Womersley数）用于 体外 研究。另一方面，流流对于混合、粒子捕获和操作非常有用。该频率范围内的振荡流也可以使用如上所述与器件23键合的压电元件来实现。通过键合压电元件实现振荡流的一个重要障碍是，它需要事先设计功能。此外，粘合的扬声器元件是不可拆卸的，并且必须将新元件粘合到每个设备24上。但是，此类设备具有紧凑的优点。另一种方法是使用机电继电器阀20。这些阀门需要气动压力源和定制控制软件来操作，因此增加了测试和实施的技术障碍。然而，这种装置能够应用设定的压力幅度和频率。
本文介绍了一种用户友好型方法的构造、操作和表征，以在微通道中产生频率范围为10-1000 Hz的振荡流。该方法具有许多优点，例如经济高效的组装，易于操作，并随时可以与标准微流体通道和附件（如注射泵和管道）连接。此外，与以前的类似方法25相比，该方法为用户提供了对振荡频率和幅度的选择性和独立控制，包括正弦和非正弦波形之间的调制。这些功能使用户能够轻松部署振荡流，从而促进在生物学和化学领域广泛采用当前存在的各种微流体技术和应用。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Oscillatory Driver Assembly</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Alligator-to-pin wire</td>
			<td>Adafruit</td>
			<td>3255</td>
			<td>Small alligator clip to male jumper wire (12)</td>
		</tr>
		<tr>
			<td>Aux cable</td>
			<td>Adafruit</td>
			<td>2698</td>
			<td>3.5 mm Male/Male stereo cable 1 m</td>
		</tr>
		<tr>
			<td>Controller chip</td>
			<td>Damgoo</td>
			<td>TPA3116</td>
			<td>50w+50w 2 channel audio amplifier (bluetooth and AUX)</td>
		</tr>
		<tr>
			<td>DC adapter</td>
			<td>Adafruit</td>
			<td>798</td>
			<td>12 V DC 1A regulated switching power adapter</td>
		</tr>
		<tr>
			<td>Micro-pipette tip</td>
			<td>VWR Signature</td>
			<td>37001-532</td>
			<td>200 ul micropipette tip</td>
		</tr>
		<tr>
			<td>Silicone sealant</td>
			<td>Loctite</td>
			<td>908570</td>
			<td>Clear silicone waterproof sealant (80 ml)</td>
		</tr>
		<tr>
			<td>Speaker</td>
			<td>Drok</td>
			<td>6843996</td>
			<td>4.5 inch 4 Ohm 40 W speaker</td>
		</tr>
		<tr>
			<td>Speaker mount</td>
			<td></td>
			<td></td>
			<td>3D printed from &#39;speakermount.stl&#39; in supplementary files</td>
		</tr>
		<tr>
			<td>Speaker-to-tube adapter</td>
			<td></td>
			<td></td>
			<td>3D printed from &#39;speaketubeadapter.stl&#39; in supplementary files</td>
		</tr>
		<tr>
			<td>Microchannel Manufacture</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Biopsy punch</td>
			<td>Miltex</td>
			<td>15110</td>
			<td>Biopsy punch with plunger (1 - 4 mm)</td>
		</tr>
		<tr>
			<td>Degasser</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable cup</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable spoon</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Slides</td>
			<td>VWR Signature</td>
			<td>16004-430</td>
			<td>3&#34; x 1&#34; pre clean 1 mm thick</td>
		</tr>
		<tr>
			<td>Mold</td>
			<td></td>
			<td></td>
			<td>Si - SU-8 or 3D printed</td>
		</tr>
		<tr>
			<td>Oven</td>
			<td>Fischer Scientific</td>
			<td></td>
			<td>Isotemp</td>
		</tr>
		<tr>
			<td>PDMS resin and cross-linker</td>
			<td>Dow Chemical</td>
			<td>4019862</td>
			<td>Sylgard 184 PDMS resin and crosslinker (500 g)</td>
		</tr>
		<tr>
			<td>Polyethylene tubing</td>
			<td>Becton Dickinson Intramedic</td>
			<td>427440</td>
			<td>Polyethylene tubing (PE 60 - PE 200)</td>
		</tr>
		<tr>
			<td>Razor blades</td>
			<td>VWR</td>
			<td>55411-050</td>
			<td>Single edge industrial razor blades</td>
		</tr>
		<tr>
			<td>RF plasma generator</td>
			<td>Electro-Technic Products</td>
			<td>BD - 20</td>
			<td>High frequency generator</td>
		</tr>
		<tr>
			<td>Silicone Mold Release</td>
			<td>CRC</td>
			<td>03301</td>
			<td>Food Grade Silicon Mold release (16 oz)</td>
		</tr>
		<tr>
			<td>Observation and Characterization</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Camera</td>
			<td>Edgertronic</td>
			<td></td>
			<td>SC2+</td>
		</tr>
		<tr>
			<td>Lens</td>
			<td>Nikon</td>
			<td></td>
			<td>Plan Fluor 10x</td>
		</tr>
		<tr>
			<td>Microscope</td>
			<td>Nikon</td>
			<td></td>
			<td>Ti Eclipse manual stage</td>
		</tr>
		<tr>
			<td>Needles</td>
			<td>Becton Dickinson</td>
			<td>305175</td>
			<td>&#160;PrecisionGlide 20G</td>
		</tr>
		<tr>
			<td>Syringe</td>
			<td>Becton Dickinson</td>
			<td>1180100555</td>
			<td>Monoject 1 ml</td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>Harvard Apparatus</td>
			<td></td>
			<td>Dual syringe programmable syringe pump</td>
		</tr>
		<tr>
			<td>Tracer Particles</td>
			<td>Spherotech</td>
			<td>PP-10-10</td>
			<td>Polystyrene tracer particles 1 um</td>
		</tr>
	</tbody>
</table>

assembly and characterization of an external driver for the generation of sub-kilohertz oscillatory flow in microchannels

微流体技术已成为化学和生物实验室分析和合成的标准工具。液体样品（如化学试剂和细胞培养物）的注射主要通过稳定的流动来完成，这些流动通常由注射泵，重力或毛细管力驱动。互补振荡流的使用很少在应用中考虑，尽管它具有最近在文献中证明的众多优点。在微通道中实现振荡流的重大技术障碍可能是其缺乏广泛采用的原因。可以产生振荡流量的先进商用注射泵通常更昂贵，并且仅适用于低于1 Hz的频率。在这里，演示了一种低成本、即插即用型扬声器设备的组装和操作，该设备在微通道中产生振荡流。可实现频率范围为 10-1000 Hz 的高保真谐波振荡流以及独立的幅度控制。在整个工作范围内可实现 10-600 μm 的幅度，包括在典型微通道中谐振频率下> 1 mm 的幅度。虽然振荡频率由扬声器决定，但我们说明了振荡幅度对流体特性和通道几何形状敏感。具体而言，振荡幅度随着通道电路长度和液体粘度的增加而减小，而相反，振幅随着扬声器管厚度和长度的增加而增加。此外，该装置不需要在微通道上设计先前的特征，并且易于拆卸。它可以与注射泵产生的稳定流量同时使用，以产生脉动流量。

为了说明上述设置的功能和性能，给出了具有方形横截面的简单线性微通道中振荡流的代表性结果。通道的宽度和高度为110μm，长度为5厘米。首先，我们描述了球形聚苯乙烯示踪剂颗粒的运动，以及如何使用这些颗粒来检查振荡信号的保真度以及可实现的振荡幅度范围。然后，我们讨论特定流体性质或微流体材料对振荡幅度的影响。最后，我们说明了非正弦波形的能力。
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Watch this Scientific Journal Video about Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels at JoVE.com

Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels

该协议演示了一种在微信道中产生10-1000 Hz谐波振荡流的便捷方法。这是通过将计算机控制的扬声器振膜以模块化方式连接到微通道来实现的。

用于在微通道中产生亚千赫兹振荡流的外部驱动器的组装和表征

Microfluidic technology has become a standard tool in chemical and biological laboratories for both analysis and synthesis. The injection of liquid ...

我们的技术使用微流体为生物学家和化学家带来振荡流。该器件组装快速，易于使用，是一种即插即用的方法，用于产生高保真振荡流。演示该程序的将是来自我实验室的博士生Giridar Vishwanathan。首先，将一对鳄鱼的鳄鱼夹末端夹紧，将电线固定到带有8厘米锥体的15瓦扬声器的端子上。将辅助控制器芯片放在绝缘组件上。将针脚端插入辅助芯片的螺钉插座。用螺丝刀拧紧以确保连接。将辅助电缆的一端连接到控制器芯片，另一端连接到计算机上的辅助端口。将 12 伏直流适配器连接到电源。通过将直流适配器的同轴端连接到电源插座来打开控制器芯片。使用互联网浏览器，导航到在线音调生成器网站。在在线应用程序中输入5至1200赫兹之间的所需频率，并将音量条滚动到所需的量。单击波形类型发生器符号，然后选择所需的波形，如符号、正方形、三角形或锯齿形。默认设置为符号波形。按播放以启动扬声器。将扬声器和控制器芯片贴在3D打印的扬声器堆上，以便在显微镜载物台上定位。将 3D 打印适配器同心放在扬声器锥体上。沿着适配器的边缘大量涂抹硅酮密封胶，并固化两小时。将一个200微升的微量移液器尖端从其狭窄的末端切割约两厘米，并处理较宽的一半尖端，其中狭窄的锥形末端将用作可逆连接的楔形密封。将聚乙烯管通过首先通过微移液管尖端的螺纹连接到微通道输出，然后通过适配器的同轴端，最后通过侧面出来。将移液器吸头的窄端牢固地楔入适配器的同轴端，以形成可拆卸的紧密密封。将示踪剂颗粒加入到重量为22%的甘油溶液中，以在20摄氏度的液体中产生体积分数为0.01%至0.1%聚苯乙烯的中性浮力悬浮液。通过摇晃剧烈混合以产生均匀的悬浮液。将一毫升进样注射器装入一毫升样品。将装载的注射器堆放并固定到自动注射器泵上。将注射器针头插入设备的入口管中，以形成水密密封。确保出口管通过适配器组件扎根并进入储液罐。打开注射器泵，使用触摸屏选择注射器类型为Becton-Dickinson 1 mL，然后选择Infuse。然后选择所需的流量流量。使用注射泵启动稳定流量。等到出口管装满液体直至扬声器。在音调发生器应用程序中选择所需的频率幅度和波形，然后按播放以在微通道内生成振荡流。将设备安装在显微镜上。通过选择放大倍率在10X至40X之间的物镜，并调整焦平面和定位载物台来设置光学配置。要在明确定义的焦平面上获得测量值，请确保物镜的景深比通道深度小五倍或更多。要观察振荡流，请使用帧速率至少为振荡频率两倍的高速相机。为了获得波形的有用分辨率，每个时间段至少测量10个点，其帧速率比振荡频率高10倍。或者，为了观察正流的长期效应，通过将观察结果设置为振荡频率的任何完美除数来执行频闪成像。对于直接成像和频闪成像，请使用配备全局快门的相机，以避免果冻效应。在任何一种情况下，将曝光时间比振荡时间段小10倍或更多，以防止条纹。要在没有高速相机的情况下测量振荡幅度，请以接近但不接近频闪帧速率的帧速率进行记录，这会导致高度减慢的振荡，从中可以精确地测量，观察和记录幅度测量值。跟踪示踪粒子在通道中平面的位移显示振荡频率为100、200、400和800赫兹的谐波信号。在所有扬声器音量设置的振荡幅度与频率的关系图中，特征曲线在大约180赫兹时具有共振峰值，超过该峰值时幅度随着频率的增加而减小。相对于参考情况，不同参数对工作频率范围内振荡幅度的影响表明，当工作液体的粘度增加时，振幅降低近两倍。当相同材料的微流体管直径增加时，振幅与参考情况相比增加1.5至3倍，具体取决于频率。当相同材料的管长增加时，振幅在谐振频率附近显着增加。非正弦波形式的粒子位移轨迹表明，在实际系统中不可能实现与方波和锯齿波形式相关的位置的非常剧烈的变化。尽管如此，傅里叶光谱与理想光谱非常吻合，至少在三次谐波之前是这样。重要的是要确认出口管完全充满液体。这确保了振幅最大，并且随时间变化恒定。还必须使用带有全局快门的相机。我们已经使用这种技术来精确观察和测量微米级颗粒在微通道内行进很长一段距离后的行为。这使我们能够实施新的微流体操作技术。

Research

JoVE Journal

Engineering

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry

代高阶拉盖尔 - 高斯光束的高精度干涉

Thermal noise in high-reflectivity mirrors is a major impediment for several  types of high-precision interferometric experiments that aim to reach the  ...

科研

工程学

Construction and Characterization of External Cavity Diode Lasers for Atomic Physics

外腔半导体激光器的原子物理的构建与鉴定

Since their development in the late 1980s, cheap, reliable external cavity diode lasers (ECDLs) have replaced complex and expensive traditional dye and ...

Patterning via Optical Saturable Transitions - Fabrication and Characterization

通过光学吸收跃迁图案 - 制备与表征

This protocol describes the fabrication and characterization of nanostructures using a novel nanolithographic technique called Patterning via Optical ...

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

电子通道造影的快速III-V异质特征

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

全套材料常数表征及其温度依赖性的压电材料使用共振超声波谱

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Characterization of Ultra-fine Grained and Nanocrystalline Materials Using Transmission Kikuchi Diffraction

超细晶和纳米晶材料的表征采用透射菊池衍射

One of the challenges in microstructure analysis nowadays resides in the reliable and accurate characterization of ultra-fine grained (UFG) and ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

一种新的方法<em&gt;原位</em&gt;纳米级样品的机电表征

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

光诱导的宏观振荡运动液晶网络的制备

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous ...

Generation of Size-controlled Poly (ethylene Glycol) Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Generation of Size-controlled Poly ethylene Glycol Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Semi-3-Dimensional 流聚焦微流控装置产生尺寸控制的聚乙二醇二丙烯酸酯液滴

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. ...

Studying Large Amplitude Oscillatory Shear Response of Soft Materials

软材料大振幅振荡剪切响应的研究

We investigate the sequence of physical processes exhibited during large amplitude oscillatory shearing (LAOS) of polyethylene oxide (PEO) in dimethyl ...