通过工业/大学合作研究中心的水处理设备和位于威斯康星州密尔沃基（IIP-0968887）和马凯特大学（IIP-0968844）的大学政策提供了由美国国家科学基金会为这项工作的部分资金支持。我们感谢格伦·沃克先生，宇晋Chang和香卡拉达克里希南有益的讨论。

1.热粒子探测（TPD） <ol><li>用薄膜的氮化硅膜和集成温度传感器通过微加工制备微制造硅器件，使用标准的半导体加工技术2。冲洗所制造的设备，用去离子（DI）水。 注意:该制造方法的热粒子检测器的微流体装置在现有出版物2进行说明。 </li><li>以生产微通道聚二甲基硅氧烷（PDMS）衬底，创建使用标准光刻技术的模具SU8处理5。 注意:通道尺寸被设计为每个特定的颗粒的尺寸。 <ol><li>使PDMS通过混合10:1的比例碱（30毫升）和固化剂（3毫升）中。倒到模具中的PDMS和由短暂暴露到真空（5-10分钟）除去气泡。 注:真空水平不是一个临界值，以脱气，并应继续进行，直到气体巴布文件被从混合PDMS完全去除。 </li><li>放置在热板上（〜70℃）的模具2小时，以固化的PDMS。然后剥去PDMS非常小心，以免损坏模具。 注:真空水平不是一个临界值。 </li></ol></li><li>使用手动冲头，冲头紧孔（1毫米）的PTFE管的一端。使用大的冲头（2毫米）的另一端，使PDMS的贮存器。放置在设备顶部的冲孔微通道，在显微镜下，并对准热电阻在微通道（ 图1A）的中心。 </li><li>在电气接口，连接电销在接触垫仓和收紧锁紧螺钉。确保高度可调节销（Pogo的引脚）坐在该装置上的正确的电极垫。 </li><li>稀释10微升的浓的PS珠在100微升去离子水在1.5ml管中。 </li><li>为了保证PS珠保持中性浮力，加2.7微升甘油（1.26克/厘米3），以DI水以匹配流体密度的聚苯乙烯（PS）珠密度（1.05克/厘米3）。 </li><li> PTFE管连接到所述通道的一端和另一端，以1毫升的玻璃注射器。填用0.5ml去离子水的玻璃注射器。 注:通过选择合适的冲规模将避免漏管做紧身。 </li><li>将充满的注射器上的计算机控制的注射泵的DI水。推水（5-20​​微升/分钟）到通道以填充整个通道与流体一路到储存器。 </li><li>负载10微升均衡珠溶液的贮存器，并通过改变对注射泵的流动方向引入珠溶液的微通道。 </li><li>由偏置DC电流为1mA通过计算机控制的源/米而测量由源/米的电阻和排序所测量的数据（ 图2）打开的RTD。 注:在实验过程中，传感器偏置;因此，该温度被连续地测量，直到计数实验结束。在RTD传感器通过施加直流电流范围为100微安到1毫安连续测量温度，直至计数实验结束电偏置。关键是要选择正确的电流电平，因为有噪声水平和检测到的信号幅度之间存在折衷。注射泵被用来产生在微通道的流动。选择一个适当的流动速率来执行TPD实验中限制到测量的速度。这个速度是设备和电气测量速度的热时间常数的函数。热粒子检测实验的结果示于图3。 </li><li>使用开发的数据处理软件（LabVIEW中），以使用的Callendar-凡杜森方程6所测量的电阻数据转换为温度。 </li></ol> 2.热液体物质使用微热量计的表征<ol><li>在此过程中，使用芯片上量热装置（ 图4A）3来测量热扩散系数和样品的比热。 注:在每个死亡，还有2微热量计室（ 图4B）。每室有2个入口和一个出口。且每个腔室具​​有加热器和RTD传感器集成。 </li><li>将装置保持器（ 图4C）上的微量热设备。该装置对准到微流体的入口和出口与支架配件。放置在设备顶部的PDMS密封层。 </li><li>该装置保持器上安装的电连接销和锁定保持器螺钉。 注:确保高度可调弹簧针与电接触垫对齐。 </li><li>安装有磁性闩锁到装置保持器（ 图4D）微流体界面层。连接PTFE铝管两者的入口和出口。一个入口连接到示例加载注射器泵并关闭另一个，作为焓没有在这种情况下进行测量。 </li><li>使用开发的计算机控制的程序中，以将样品加载到微通道和腔室。 注意:程序将使用停产流以释放过大的压力的薄膜悬浮室。 <ol><li>的300微升样品加载到玻璃注射器，并将其放置在注射器泵。使用非常缓慢（0.25微升/分钟）恒定流速为高粘度样品（ 例如 ，甘油和离子液体）。使用热扩散系数的测量和离子液体比热测量甘油样品。 </li></ol></li><li>测量<ol><li>热扩散系数的测量<ol><li>连接测量设置为如图5A所示。加载甘油样品到微热量计室。运行老天修改后的计算机控制程序<html>牛逼穿透时间的测量。 </li><li>使用校准的热穿透方程来计算测量热穿透时间7热扩散系数: <img alt="式（1）" src="/files/ftp_upload/52828/52828eq1.jpg" width="100" /> 其中，α是热扩散率，L是腔室的厚度，p是厚度校准因数由于制造工艺的变化，而​​t 0是热渗透时间。 </li></ol></li><li>比热测量<ol><li>使用TWA测量设置， 如图5B所示 。使用相同的样品装载程序并装入离子液体在腔室中。运行TWA程序来获得交流电的温度波动（∂Ť 交流 ）的振幅，并使用比热公式来计算特定， 中 c p，热每个离子液体样品8: 28eq2.jpg"WIDTH ="117"/&gt; 其中，C 0是输入功率校准因数，P 在被输入功率，ω是致动信号的频率，而m是液体样品的质量。 </li></ol></li></ol></li></ol> 3.量热生化检测纸基微流体装置<ol><li>使用微加工薄膜（40-50纳米镍）RTD传感器。制造步骤的RTD传感器在以前的作品中4解释。 </li><li>对于纸质通道制造4，用小刀绘图仪切纸微流体通道与设计的图案（L形）。将打印纸在切割垫的顶部，装入纸张和切割垫刀绘图仪，并使用适当的配方来切断微流体纸张通道4。 </li><li>对于设备和渠道整合，使用丙烯酸粘合剂层（5微米）到纸张上集成了RTD传感器。使用清洁提单拉德到纸张推送到设备和除去气泡（ 图6A）。丙烯酸类膜是粘接剂层，以保持纸在RTD传感器。 </li><li>酶的激活，使用50mM乙酸钠缓冲液以激活GOD酶。加入1毫克的GOD酶到1ml的醋酸钠缓冲液以使1mg / ml的溶液。调节溶液的pH至5.1。 注意:调节在乙酸钠缓冲液的乙酸的量，以保持溶液5.1的PH值。 </li><li>偏置RTD直流毫安1电流激活RTD，然后开始连续测量电阻源/米，而阻实验（〜4分钟）后稳定下来。 注: 图6B显示测量设置的基于纸张的测试量热。 </li><li>引入2微升制备GOD溶液到纸张微通道（固定点）经由吸移管的中心。检测到的温度（ 图7A）必须启动吨Ø减少。 注意:此冷却效果是由于RTD的更高的工作温度的样本的和蒸发一起。 </li><li>为了测量葡萄糖浓度，引入标准葡萄糖对照溶液9至通道入口和测量所引起的反应电阻变化。重复这个实验的所有不同的血糖控制解决方案（高，普通，低浓度），并保存电阻数据。 </li><li>使用电阻（TCR）的镍RTD和的Callendar-凡杜森方程的温度系数，转换所述电阻变化对温度。通过考虑葡萄糖的反应焓和GOD酶（ΔH = -80千焦耳/摩尔），并使用浓度方程10计算每个样品中的葡萄糖的浓度: <img alt="公式3" src="/files/ftp_upload/52828/52828eq3.jpg" width="83" /> 其中n p被检测摩尔浓度，C <sub&gt; p是该系统的热容量和ΔT计算温度。 </li></ol>

<ol>
	<li>Zhang, H., Chon, C., Pan, X., Li, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+counting+particles+in+microfluidic+applications.">Methods for counting particles in microfluidic applications.</a> Microfluid Nanofluid. 7 (6), 739-749 (2009).</li><li>Vutha, A. K., Davaji, B., Lee, C. H., Walker, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+microfluidic+device+for+thermal+particle+detection.">A microfluidic device for thermal particle detection.</a> Microfluid Nanofluid. 17 (5), 871-878 (2014).</li><li>Davaji, B., Bak, H. J., Chang, W. J., Lee, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+On-chip+Three-dimensional+Micromachined+Calorimeter+with+Fully+Enclosed+and+Suspended+Thin-film+Chamber+for+Thermal+Characterization+of+Liquid+Samples.">A Novel On-chip Three-dimensional Micromachined Calorimeter with Fully Enclosed and Suspended Thin-film Chamber for Thermal Characterization of Liquid Samples.</a> Biomicrofluidics. 8 (3), 034101-034113 (2014).</li><li>Davaji, B., Lee, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+paper-based+calorimetric+microfluidics+platform+for+bio-chemical+sensing.">A paper-based calorimetric microfluidics platform for bio-chemical sensing.</a> Biosens. Bioelectron. 59, 120-126 (2014).</li><li>Liu, 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=Process+research+of+high+aspect+ratio+microstructure+using+SU-8+resist.">Process research of high aspect ratio microstructure using SU-8 resist.</a> Microsystem Technologies. 10, 265-268 (2004).</li><li>Dusen, M. S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Platinum-resistance+thermometry+at+low+temperatures.">Platinum-resistance thermometry at low temperatures.</a> J. Am. Chem. Soc. 47 (2), 326-332 (1925).</li><li>Arpaci, V. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Conduction Heat Transfer. , (1966).</li><li>Garden, J. L., Chteau, E., Chaussy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+sensitive+ac+nanocalorimeter+for+microliter-scale+liquids+or+biological+samples.">Highly sensitive ac nanocalorimeter for microliter-scale liquids or biological samples.</a> Appl. Phys. Lett. 84, 3597-3599 (2004).</li><li>Kilo, C., 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=Evaluation+of+a+New+Blood+Glucose+Monitoring+System+with+Auto-Calibration.">Evaluation of a New Blood Glucose Monitoring System with Auto-Calibration.</a> Diabetes Technol. Ther. 7 (2), 283-294 (2005).</li><li>Scheper, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Thermal Biosensors Bioactivity Bioaffinity (Advances in Biochemical Engineering/Biotechnology). , (1999).</li></ol>

没有利益冲突的声明。

Different thermal measurement techniques in microfluidic devices and their respective setup procedures are presented in this work. These thermal measurement methods such as thermal conductivity monitoring, thermal penetration time, amplitude of AC thermal fluctuations, and amplitude measurement of the generated heat are used to detect specific substances and investigate different reactions and interactions. 
The thermal time constant plays a key role in the aforementioned thermal measurement t...

三个不同的微观尺度的热测量技术呈现在这篇文章。微流体装置的三个不同的配置被用于热粒子检测（TPD），热特性（热导率和比热），和量热检测化学反应和相互作用。 热粒子探测检测和计数在微流体装置的粒子被广泛用于环境，工业和生物应用1。 TPD是热测量的在微流体装置2的新的应用中的一个。使用传热，用于检测和计数基于所述粒径的粒子降低了复杂性，成本和系统的大小。在其他方法中，复杂的光学或复杂的电气测量和先进的信号处理的软件用于检测颗粒。 热甜心液体物质cterization利用微热量计液体样品的热特性是热计量的微流体装置的第二个应用程序。执行微尺度量热将降低样品消耗和通过提供更高的重复性相比于常规，散装量热方法提高精度。的程序使用芯片上的微量热设备的热导率和比热测量在别处3呈现。对于热导率测量的热渗透时间技术和热波分析（TWA）为在微流体装置的比热测量的细节在协议部分中描述。 量热生物化工检测纸张为基础的微流控设备热测量的另一种应用是生化检测在纸基微流体。在毛细作用的纸的多孔结构承载的液体，避免了在微通道气泡引发问题。在纸基微流体装置中最常见的检测机制是光学或电化学技术。光学检测患有高复杂性和先进的图像处理软件的必要性量化检测到的信号。电化学检测也受到限制，因为它们只能被应用到产生活性的副产物的反应。最近推出的量热纸基生化传感器平台4取纸基微流体系统和无标记的热检测机构的优点。量热检测用葡萄糖氧化酶（GOD）酶在纸基微流体平台葡萄糖的程序都在协议部分。 本文的目的是展示在微流体装置的热测量技术的功能。该器件preparatioN，液体样品处理和电阻温度检测器（RTD）传感器激励和测量列于下一个章节。

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Polydimethylsiloxane (PDMS)&#160;</td>
			<td>Dow Corning</td>
			<td>Sylgard 184</td>
			<td></td>
		</tr>
		<tr>
			<td>PS beads - 90 um&#160;</td>
			<td>Corpuscular</td>
			<td>100265</td>
			<td></td>
		</tr>
		<tr>
			<td>PS beads - 200 um&#160;</td>
			<td>Corpuscular</td>
			<td>100271</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>SigmaAldrich</td>
			<td>G5516</td>
			<td></td>
		</tr>
		<tr>
			<td>GOD enzyme</td>
			<td>SigmaAldrich</td>
			<td>G7141</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose Control Solution-Low</td>
			<td>Bayer contour</td>
			<td>Low Control</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose Control Solution-Normal</td>
			<td>Bayer contour</td>
			<td>Normal Control</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose Control Solution-High</td>
			<td>Bayer contour</td>
			<td>High Control</td>
			<td></td>
		</tr>
		<tr>
			<td>Chromatography filter paper</td>
			<td>Whatman</td>
			<td>3001-845</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass</td>
			<td>VWR&#160;</td>
			<td>48393-106</td>
			<td></td>
		</tr>
		<tr>
			<td>Acrylic Film</td>
			<td>Nitto Denko</td>
			<td>5600</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass syringe (1 mL)</td>
			<td>Hamilton</td>
			<td>1001</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe pump</td>
			<td>New Era</td>
			<td>NE-500</td>
			<td></td>
		</tr>
		<tr>
			<td>knife plotter</td>
			<td>Silhouette</td>
			<td>portrait</td>
			<td></td>
		</tr>
		<tr>
			<td>Current Preamplifier</td>
			<td>Stanford Research</td>
			<td>SR-570</td>
			<td></td>
		</tr>
		<tr>
			<td>Ocilloscope</td>
			<td>Agilent</td>
			<td>DSO 2420A</td>
			<td></td>
		</tr>
		<tr>
			<td>Signal Generator</td>
			<td>HP</td>
			<td>HP3324A</td>
			<td></td>
		</tr>
		<tr>
			<td>Lock-in Amplifire</td>
			<td>Stanford Research</td>
			<td>SRS-830</td>
			<td></td>
		</tr>
		<tr>
			<td>Source/meter 2400</td>
			<td>Keithley</td>
			<td>2400</td>
			<td></td>
		</tr>
		<tr>
			<td>Source/meter 2600</td>
			<td>Keithley</td>
			<td>2436A</td>
			<td></td>
		</tr>
	</tbody>
</table>

thermal measurement techniques in analytical microfluidic devices

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. Micromachining techniques allow reduction of the thermal mass of fabricated structures and introduce the possibility to perform high sensitivity thermal measurements in the micro-scale and nano-scale devices. Combining thermal measurement techniques with microfluidic devices allows performing different analytical measurements with low sample consumption and reduced measurement time by integrating the miniaturized system on a single chip. The procedures of thermal measurement techniques for particle detection, material characterization, and chemical detection are introduced in this paper.

图3示出了测得的热信号的曲线图。在与相应的光学图像的小珠的存在下所产生的信号显示了成功的检测，在微通道的微球PS珠。液体穿过微通道的导热性发生变化，由于PS的珠的存在。这种变化在通道的热导率是影响在微通道的热传递。在微通道的热传递的变化是由热电阻的电阻波动（ 图3A和B）的形式进行检测。 检测到的信号也可以受?...

Watch this Scientific Journal Video about Thermal Measurement Techniques in Analytical Microfluidic Devices at JoVE.com

Thermal Measurement Techniques in Analytical Microfluidic Devices

Here, we present three protocols for thermal measurements in microfluidic devices.

在分析微流体装置的热测量技术

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. ...

thermal-measurement-techniques-in-analytical-microfluidic-devices

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

9.6K 次观看.  Marquette University. Here, we present three protocols for thermal measurements in microfluidic devices. 

视频: Thermal Measurement Techniques in Analytical Microfluidic Devices

Characterization of Thermal Transport in One-dimensional Solid Materials

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including conductive, semi-conductive or nonconductive one-dimensional structures. This technique broadens the measurement scope of materials (conductive and nonconductive) and improves the accuracy and stability. If the sample (especially biomaterials, such as human head hair, spider silk, and silkworm silk) is not conductive, it will be coated with a gold layer to make it electronically conductive. The effect of parasitic conduction and radiative losses on the thermal diffusivity can be subtracted during data processing. Then the real thermal conductivity can be calculated with the given value of volume-based specific heat (&#961;cp), which can be obtained from calibration, noncontact photo-thermal technique or measuring the density and specific heat separately. In this work, human head hair samples are used to show how to set up the experiment, process the experimental data, and subtract the effect of parasitic conduction and radiative losses.

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials.

在一维固体材料的热传输的特性

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including ...

科研

工程学

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical electrohydrodynamic liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields and polar dielectric liquids. The construction of basic apparatus and operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

高压直流电桥从极地介电液的制备

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

介电微粒的光阱装载在空气中

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each thermoplastic of interest. Solvent bonding is a simple and versatile method that can be used to fabricate devices from a variety of plastics. An appropriate solvent is added between two device layers to be bonded, and heat and pressure are applied to the device to facilitate the bonding. By using an appropriate combination of solvent, plastic, heat, and pressure, the device can be sealed with a high quality bond, characterized as having high bond coverage, bond strength, optical clarity, durability over time, and low deformation or damage to microfeature geometry. We describe the procedure for bonding devices made from two popular thermoplastics, poly(methyl-methacrylate) (PMMA), and cyclo-olefin polymer (COP), as well as a variety of methods to characterize the quality of the resulting bonds, and strategies to troubleshoot low quality bonds. These methods can be used to develop new solvent bonding protocols for other plastic-solvent systems.

Solvent bonding is a simple and versatile method for fabricating thermoplastic microfluidic devices with high quality bonds. We describe a protocol to achieve strong, optically clear bonds in PMMA and COP microfluidic devices that preserve microfeature details, by a judicious combination of pressure, temperature, an appropriate solvent, and device geometry.

溶剂粘接的PMMA的制备和COP微流体装置

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each ...

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&#233; Fringes

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moir&#233; method or the spatial phase-shifting sampling moir&#233; method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moir&#233; fringes are generated to reconstruct a multiplication moir&#233; pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moir&#233; method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moir&#233; fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moir&#233; techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

A sampling moir&#233; technique featuring 2-pixel and multi-pixel sampling methods for high-accuracy strain distribution measurements at the micro/nano-scale is presented here.

微米/纳米尺度应变分布测量从采样莫尔条纹

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. ...

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

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. This paper proposes a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation. The polydimethylsiloxane (PDMS) chip was fabricated using the multi-layer soft lithography method. Hexadecane containing surfactant was used as the continuous phase, and PEGDA with the ultraviolet (UV) photo-initiator was the dispersed phase. Surfactants allowed the local surface tension to drop and formed a more cusped tip which promoted breaking into tiny micro-droplets. As the pressure of dispersed phase was constant, the size of droplets became smaller with increasing continuous phase pressure before dispersed phase flow was broken off. As a result, droplets with size variation from 1 &#181;m to 80 &#181;m in diameter could be selectively achieved by changing the pressure ratio in two inlet channels, and the average coefficient of variation was estimated to be below 7%. Furthermore, droplets could turn into micro-beads by UV exposure for photo-polymerization. Conjugating biomolecules on such micro-beads surface have many potential applications in the fields of biology and chemistry.

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

Here, we present a protocol to illustrate the fabrication processes and verifying experiments of a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation.

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. ...

Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine micro-organisms, and/or sediments in the ocean, or fluidized bed reactors and combustion processes in engineered systems. In order to study the effect of turbulence on the kinematics of particles in such flows, simultaneous measurements of both the flow and particle kinematics are required. Non-intrusive, optical flow measurement techniques for measuring turbulence, or for tracking particles, exist but measuring both simultaneously can be challenging due to interference between the techniques. The method presented herein provides a low cost and relatively simple method to make simultaneous measurements of the flow and particle kinematics. A cross section of the flow is measured using a particle image velocimetry (PIV) technique, which provides two components of velocity in the measurement plane. This technique utilizes a pulsed-laser for illumination of the seeded flow field that is imaged by a digital camera. The particle kinematics are simultaneously imaged using a light emitting diode (LED) line light that illuminates a planar cross section of the flow that overlaps with the PIV field-of-view (FOV). The line light is of low enough power that it does not affect the PIV measurements, but powerful enough to illuminate the larger particles of interest imaged using the high-speed camera. High-speed images that contain the laser pulses from the PIV technique are easily filtered by examining the summed intensity level of each high-speed image. By making the frame rate of the high-speed camera incommensurate with that of the PIV camera frame rate, the number of contaminated frames in the high-speed time series can be minimized. The technique is suitable for mean flows that are predominantly two-dimensional, contain particles that are at least 5 times the mean diameter of the PIV seeding tracers, and are low in concentration.

The technique described herein offers a low cost and relatively simple method to simultaneously measure particle kinematics and turbulence in flows with low particle concentrations. The turbulence is measured using particle image velocimetry (PIV), and particle kinematics are calculated from images obtained with a high-speed camera in an overlapping field-of-view.

流成像技术同时测量湍流和粒子运动学

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine ...

Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of data that can be obtained from an individual sample and renders it difficult to produce statistically relevant data for unique and rare materials. Resonant cavity dielectric spectroscopy is a non-destructive, contactless technique which can simultaneously interrogate both sides of a sheeted material and provide measurements which are suitable for statistical interpretations. This offers analysts the ability to quickly discriminate between sheeted materials based on composition and storage history. In this methodology article, we demonstrate how contactless resonant cavity dielectric spectroscopy may be used to differentiate between paper analytes of varying fiber species compositions, to determine the relative age of the paper, and to detect and quantify the amount of post-consumer waste (PCW) recycled fiber content in manufactured office paper.

A protocol for the non-destructive analysis of the fiber content and relative age of paper.

纤维素纸非接触式共振腔电谱研究的方法研究

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of ...

Fabrication of Nanoheight Channels Incorporating Surface Acoustic Wave Actuation via Lithium Niobate for Acoustic Nanofluidics

Controlled nanoscale manipulation of fluids is known to be exceptionally difficult due to the dominance of surface and viscous forces. Megahertz-order surface acoustic wave (SAW) devices generate tremendous acceleration on their surface, up to 108 m/s2, in turn responsible for many of the observed effects that have come to define acoustofluidics: acoustic streaming and acoustic radiation forces. These effects have been used for particle, cell, and fluid manipulation at the microscale, although more recently SAW has been used to produce similar phenomena at the nanoscale through an entirely different set of mechanisms. Controllable nanoscale fluid manipulation offers a broad range of opportunities in ultrafast fluid pumping and biomacromolecule dynamics useful for physical and biological applications. Here, we demonstrate nanoscale-height channel fabrication via room-temperature lithium niobate (LN) bonding integrated with a SAW device. We describe the entire experimental process including nano-height channel fabrication via dry etching, plasma-activated bonding on lithium niobate, the appropriate optical setup for subsequent imaging, and SAW actuation. We show representative results for fluid capillary filling and fluid draining in a nanoscale channel induced by SAW. This procedure offers a practical protocol for nanoscale channel fabrication and integration with SAW devices useful to build upon for future nanofluidics applications.

We demonstrate fabrication of nanoheight channels with the integration of surface acoustic wave actuation devices upon lithium niobate for acoustic nanofluidics via liftoff photolithography, nano-depth reactive ion etching, and room-temperature plasma surface-activated multilayer bonding of single-crystal lithium niobate, a process similarly useful for bonding lithium niobate to oxides.

通过用于声学纳米流体的尼奥布精锂结合表面声波驱动纳米高通道的制造

Controlled nanoscale manipulation of fluids is known to be exceptionally difficult due to the dominance of surface and viscous forces. Megahertz-order ...

In Situ Surface Temperature Measurement in a Conveyor Belt Furnace via Inline Infrared Thermography

Measuring the surface temperature of objects that are processed in conveyor belt furnaces is an important tool in process control and quality assurance. Currently, the surface temperature of objects processed in conveyor belt furnaces is typically measured via thermocouples. However, infrared (IR) thermography presents multiple advantages compared to thermocouple measurements, as it is a contactless, real-time, and spatially resolved method. Here, as a representative proof-of-concept example, an inline thermography system is successfully installed into an IR lamp powered solar firing furnace, which is used for the contact firing process of industrial Si solar cells. This protocol describes how to install an IR camera into a conveyor belt furnace, conduct a customer correction of a factory calibrated IR camera, and perform the evaluation of spatial surface temperature distribution on a target object.

This protocol describes how to install an infrared camera into a conveyor belt furnace, conduct a customer correction of a factory calibrated IR camera, and evaluate the spatial surface temperature distribution of an object of interest. The example objects are industrial silicon solar cells.

通过内联红外热成像在输送带炉中的原点表面温度测量

Measuring the surface temperature of objects that are processed in conveyor belt furnaces is an important tool in process control and quality assurance. ...