这项工作是由生物工程和治疗科学系加州大学旧金山分校，定量生物科学（QB3），加州理工学院的支持，并从罗杰斯家庭基金会缩小差距奖。

1，设计器件尺寸和拓扑根据实验需要使用计算机辅助设计（CAD）软件注意：选择乳液通道的直径比球形液滴的直径。这迫使液滴成圆柱形或“腊肠”形，并能更有效地picoinjection。我们的目的，我们设计了30×30微米的渠道为分别为50微米直径的液滴。 <ol><li>模型picoinjection工地后那些由硫磷等 3与该异常的通道，该金属电极被除去，因为它们是不必要的说明。 </li><li>加信道，作为法拉第壕沟（ 图1），该picoinjection网站，并在上游乳剂，使得它们从屏蔽电场的液滴之间运行。 注：这可以防止意外的合并。 </li></ol> 2，使用软Photolith制造设备海洋学技术<ol><li>生成基于使用现有的商业服务CAD文件透明光刻掩模。 </li><li>从光罩，光阻固化在硅片上产生一个主设备，如前面4所述。 </li><li> PDMS浇在包含在5cm的聚苯乙烯培养皿设备主用固化剂（11:1比例）混合。 </li><li>将主带在真空干燥器中PDMS为大约15分钟，以除去任何气泡。 </li><li>通过将其放置在95℃的烘箱中1小时，固化的PDMS装置。可替换地，PDMS将24小时后固化在RT。 </li><li>通过削减在周边用手术刀片，小心剥离从主设备中删除该设备。 </li><li>冲入口，并使用0.5mm的活检穿孔器出口孔进入PDMS。 </li><li>使用等离子焊接机4粘合设备到玻璃显微镜幻灯片。 </li></ol> 3，准备一个气压控制泵加压到一个水库容纳流体<ol><li>通过2.7毫米的内直径的聚乙烯管的长度改变泵的输出，使得所述加压空气出口。 </li><li>构造它，使得由管子上的路厄氏锁的后部嵌合的管腔通过乳头终止于路厄锁注射器尖端。 </li><li>通过填充鲁尔锁的线程并用环氧树脂管之间的空间密封。 </li><li>附上27.5号针头。 </li></ol> 4，准备一个单分散乳液的水（水包油）悬浮于惰性氟基础油与2％（重量/重量）液滴溶解生物相容性表面活性7 包含在这些液滴中的特定试剂取决于应用<ol><li>在准备回注，加载乳液为1 ml注射器用27.5号针头。 </li><li>安全注射器在注射器泵和定向的泵的垂直（针向上）。 注：这种定位使得水滴在一层载体油上面收拾。当泵启动时，液滴将根据他们的油层被压出注射器在高体积分数。 </li></ol> 5，准备试剂介绍微流控芯片<ol><li>冲30.5毫米孔入15ml离心管（带旋盖任何容器就足够了），用活检穿孔器，针或钻的上限。 </li><li>插入一个0.5mm直径的线电极和PE-2管道的约20厘米长通过两个孔，使得它们到达管底。 </li><li>在剩余的孔中，一个线程〜2.5厘米PE管材的约20厘米长的，使得其将休息高于液体高度。 </li><li>密封件用UV固化的环氧树脂的盖的顶部没有任何间隙。 </li><li>填充管与picoinjection流体和螺钉上的盖子。 </li><li>从空气压力控制泵的输出连接管通过插入较短的长度，以ing的针刺入管腔。针应紧贴。 </li><li>填写1毫升注射器1 M氯化钠作为法拉第护城河。 </li><li>连接一个27.5号针头并固定在注射器注射泵。 </li><li>填写另有1毫升注射器与运营商/油隔，连接27.5号针头，并且将其固定在注射泵。 </li></ol> 6，准备了微流控装置Picoinjection <ol><li>从注射流体容器连接输出管（长径）向所述微流体芯片上的picoinjection流体的入口。 </li><li>连接含有1M NaCl的用于法拉第壕沟的入口端口的微流控芯片用PE管的长度上的注射器。 </li><li>连接包含载体油的微流控芯片用PE管的长度的进气口的注射器。 </li><li>将PE管材到微流体芯片上的乳状液出口。油管应终止在乳液收集容器，也不马利1.5 ml的离心管中。 </li><li>将PE管材成法拉第护城河出口的微流控芯片上。管道应终止在一个不导电的，电隔离的容器，以防止短路。 </li><li>高电压（HV）放大器通过鳄鱼夹的输出连接到淹没在picoinjection流体金属电极。 </li><li>经由鳄鱼夹连接高压放大器的接地电极，以含1M NaCl的注射器针头的金属。 </li></ol> 7，输液试剂为微流控芯片<ol><li>介绍了1M NaCl的（法拉第壕沟）到设备在100的速率 微升/小时。 </li><li>介绍在适合于该设备的尺寸率液滴乳剂和载体油。对于我们的演示设备，介绍200分别滴石油和400微升/小时。流速应该让液滴通过picoinjector在分离定期通过载体油的差距。 </li><li>调整施加到picoinjection流体使得在picoinjection孔中的流体压力与所述液滴通道机械平衡的压力。 注意：在这个压力（拉普拉斯压力），注射液应隆起成液滴通道，而萌芽了，并形成了自己滴（ 图2）。在上述这些流速下，可以应用的〜13 psi的压力来喷射流体，以达到平衡，在注射部位。 </li></ol> 8。 开始Picoinjection <ol><li>作为液滴通过喷射孔，应用一个0-10伏，10千赫，交流信号放大1000×由HV型放大器（ 图3）。 </li><li>通过改变施加的电压的振幅调制的注射体积。 注意：较高的电压应该允许更多的流体被引入到液滴。在我们的测试中，我们观察到稳定持续注入，在电压是之间100和3,000 V采用氯化钠注射液，范围从10-500毫米（ 图4）。 </li></ol>

<ol>
	<li>Kritikou, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=It's+cheaper+in+the+Picolab.">It's cheaper in the Picolab.</a> Nat. Rev. Genet. 6 (9), (2005).</li><li>Ahn, K., Agresti, J., Chong, H., Marquez, M., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrocoalescence+of+drops+synchronized+by+size-dependent+flow+in+microfluidic+channels.">Electrocoalescence of drops synchronized by size-dependent flow in microfluidic channels.</a> Appl. Phys. Lett. 88 (26), (2006).</li><li>Abate, A. R., Hung, T., Mary, P., Agresti, J. J., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+injection+with+microfluidics+using+picoinjectors.">High-throughput injection with microfluidics using picoinjectors.</a> Proc. Natl. Acad. Sci. U S A. 107, 19163-19166 (2010).</li><li>Harris, 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=Fabrication+of+a+microfluidic+device+for+the+compartmentalization+of+neuron+soma+and+axons.">Fabrication of a microfluidic device for the compartmentalization of neuron soma and axons.</a> J. Vis. Exp. (7), (2007).</li><li>Duffy, D. C., McDonald, J. C., Schueller, O. J., Whitesides, 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=Rapid+prototyping+of+microfluidic+systems+in+poly(dimethylsiloxane).">Rapid prototyping of microfluidic systems in poly(dimethylsiloxane).</a> Anal. Chem. 70 (23), 4974-4984 (1998).</li><li>O'Donovan, B., Eastburn, D. J., Abate, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrode-free+picoinjection+of+microfluidic+drops.">Electrode-free picoinjection of microfluidic drops.</a> Lab on a Chip. 12 (20), 4029-4032 (2012).</li><li>Holtze, 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=Biocompatible+surfactants+for+water-in-fluorocarbon+emulsions.">Biocompatible surfactants for water-in-fluorocarbon emulsions.</a> Lab on a Chip. 8 (10), 1632-1639 (2008).</li><li>Chung, C., Lee, M., Char, K., Ahn, K., Lee, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Droplet+dynamics+passing+through+obstructions+in+confined+microchannel+flow.">Droplet dynamics passing through obstructions in confined microchannel flow.</a> Microfluid. Nanofluid. 9, 1151-1163 (2010).</li><li>Herminghaus, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamical+instability+of+thin+liquid+films+between+conducting+media.">Dynamical instability of thin liquid films between conducting media.</a> Phys. Rev. Lett. 83 (12), 2359-2361 (1999).</li><li>Priest, C., Herminghaus, S., Seemann, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+electrocoalescence+in+microfluidics:+Targeting+a+single+lamella.">Controlled electrocoalescence in microfluidics: Targeting a single lamella.</a> Appl. Phys. Lett. 89 (13), 134101-134103 (2006).</li><li>Florent, M., Siva, A. V., Hao, G., Dirk, E., Frieder, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrowetting-controlled+droplet+generation+in+a+microfluidic+flow-focusing+device.">Electrowetting-controlled droplet generation in a microfluidic flow-focusing device.</a> J. Phys: Condens. Matter. 19 (46), (2007).</li><li>Eastburn, D. J., Sciambi, A., Abate, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Picoinjection+enables+digital+detection+of+RNA+with+droplet+rt-PCR.">Picoinjection enables digital detection of RNA with droplet rt-PCR.</a> PLoS ONE. 8 (4), (2013).</li></ol>

我们并不完全理解其背后在我们的实验中观察到的施加电压和进样量之间的关系确切的物理机制。该实验室的兴趣和专长的相关领域并不非常适合追求这个挥之不去的问题。我们鼓励那些有更多的物理学和工程学的敏锐探讨这一现象。

注射量和施加的电压之间的关系依赖于许多因素，包括设备的尺寸，管携带picoinjection流体的设备，摩尔浓度picoinjection流体的长度，并且液滴的速度，因为它们通过它们喷射器。出于这个原因，我们建议量/电压的关系，通过测量的进样量在电压和摩尔浓度的工作范围的边缘被定性picoinjection的每次运行前。此外，在更高的电压和注射液的摩尔浓度，我们观察到的现象，其中picoinjection流体不再是在?...

在液滴的基于微流体，微米级的水滴被用作“试管”用于生物反应。在执行中的微小液滴反应的优点是，每一滴用试剂只有几个PL，并与微流体液滴可形成并在千赫速率1处理。结合这些特性使数以百万计的反应与个体细胞，核酸分子，或将在最小的事，总材料微升进行化合物。 使用滴像这些应用，需要技术加试剂的体积控制到滴;这样的操作是类似的移液到试管。一种用于实现这一点是electrocoalescence，其中一滴试剂是通过施加电场合并与靶下降。的电场扰乱了表面活性剂分子的结构上的液滴的界面，INDucing薄膜的不稳定性和乳液触发聚结是稳定的，否则2。电诱导融合也利用在picoinjector，即注入的试剂成液滴，因为它们流过的加压通道3的设备的设计。以应用电场，picoinjector装置利用金属电极，但金属电极集成到微流控芯片通常是一个复杂且容易出错的过程，作为液体焊料导线由气泡或灰尘等杂物的通道容易受到损害，以及从应力性骨折或设备安装过程中弯曲。 这里，我们提出以执行picoinjection无需使用金属电极，使得制造更简单和更可靠的方法。触发picoinjection，我们改用注射液本身作为一个电极，因为大多数生物试剂含有溶解的电解质和具有导电性。我们还添加了一个“法拉第莫阿t“的屏蔽装置，并作为一个通用地面（ 图1）的敏感区域的电壕沟通过提供一接地，以防止意外的液滴合并隔离picoinjection站点的液滴上游。我们的技术的一个好处是，在量注入滴依赖于所施加的电压的大小，允许它通过调整施加的信号进行调整。 我们采用软光刻技术制造4,5我们在聚二甲基硅氧烷设备（PDMS）。我们的方法是与制作在其它材料的设备兼容，如树脂，塑料，以及环氧树脂。该通道具有高度和宽度为30微米，这是最适合于与液滴50微米的直径（65 PL）工作。我们通过插入在设备制造与0.50毫米活检穿孔，类似的方法创建单位描述端口聚乙烯管（0.3/1.09毫米内/外径）引入试剂离子束增强沉积以前5。注入流体的精确化妆取决于具体的应用。唯一的流体需要含有溶解的电解质的浓度高到足以产生足够的导电性为要被发送到的picoinjector的电信号。在台架测试中，我们已经发现，离子浓度大于10mM的应该足够6，尽管这个值和流体的电导率取决于特定器件的尺寸和所施加的电压的幅值。

<table border="0" cellpadding="0" cellspacing="0" width="1000">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">1 mL Leur-Lok&#8482; syringes</td>
			<td style="width:143px;">BD Medical</td>
			<td align="right" style="width:160px;">309628</td>
			<td style="width:415px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LocTite UV-cured adhesive</td>
			<td style="width:143px;">Henkel</td>
			<td align="right">35241</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">PE-2 Tubing</td>
			<td style="width:143px;">Scientific Commodities</td>
			<td>BB31695-PE/2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Novec HFE-7500</td>
			<td>3M</td>
			<td style="width:160px;">98-0212-2928-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">NaCl</td>
			<td style="width:143px;">Sigma Aldrich</td>
			<td style="width:160px;">S9888</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">1.5 mL centrifuge tubes</td>
			<td style="width:143px;">Eppendorf</td>
			<td align="right" style="width:160px;">22363531</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">BD Falcon 15 ml tube</td>
			<td style="width:143px;">BD Biosciences</td>
			<td align="right" style="width:160px;">352097</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">Air Pressure Control Pump</td>
			<td style="width:143px;">Control Air Inc.</td>
			<td style="width:160px;"></td>
			<td style="width:415px;">We recommend one under the control of DAQ and control software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Syringe Pumps</td>
			<td>New Era</td>
			<td style="width:160px;"></td>
			<td>Must be capable of holding 1ml syringes and flowing at rates as low as 100 uL/hr</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">HV-Amplfier</td>
			<td style="width:143px;"></td>
			<td style="width:160px;"></td>
			<td>Must be capable of 1000x amplification of signals between 0.01 and 10 V</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plasma Bonder/Cleaner</td>
			<td style="width:143px;">Harrick Plasma</td>
			<td style="width:160px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3&#8221; silicon wafers</td>
			<td style="width:143px;">Sigma Aldrich</td>
			<td align="right" style="width:160px;">647535</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PDMS</td>
			<td style="width:143px;">Dow Corning</td>
			<td style="width:160px;"></td>
			<td>Sylgard 184 with curing agent should be included</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">SU-8 Photoresist</td>
			<td style="width:143px;">MicroChem</td>
			<td style="width:160px;"></td>
			<td>Viscocity depends on device dimensions</td>
		</tr>
	</tbody>
</table>

picoinjection of microfluidic drops without metal electrodes

对于picoinjecting试剂进入微滴现有方法需要集成到微流控芯片的金属电极。这些电极的集成增加了麻烦和容易出错的步骤，该装置的制造过程。我们已经开发了消除picoinjection在金属电极的需求的技术。相反，它使用的注射液本身作为一个电极，因为大多数生物试剂含有溶解的电解质和具有导电性。通过消除在电极上，我们减少器件的制造时间和复杂性，并且使设备更加坚固。此外，用我们的方法中，注射量取决于施加到picoinjection溶液中的电压;这使我们能够迅速调整通过调整施加电压的注入量。我们证明，我们的方法是用掺入普通的生物化合物，包括缓冲液，酶和核酸的试剂相容。

采取在picoinjection现场表演显微图像，该picoinjection流体的电气化是足以触发注射（ 图2）。注入量可以通过调节所施加的电压的振幅，具有更高的电压允许更高的喷射量进行控制。我们绘制了喷射量与所施加电压的注射液中（ 图3）3代表摩尔浓度的大小。为了演示速度我们的方法中，我们有选择地注入通过注射部位取决于存在或荧光染料（ 电影1）的缺勤液滴?...

Watch this Scientific Journal Video about Picoinjection of Microfluidic Drops Without Metal Electrodes at JoVE.com

Picoinjection of Microfluidic Drops Without Metal Electrodes

我们已经开发了用于picoinjecting微滴，不需要金属电极的技术。因此，结合我们的技术设备是简单的制造和使用。

微流控的Picoinjection滴无金属电极

Existing methods for picoinjecting reagents into microfluidic drops require metal electrodes integrated into the microfluidic chip. The integration of ...

picoinjection-of-microfluidic-drops-without-metal-electrodes

Research

JoVE Journal

Engineering

11.0K 次观看.  Unversity of California, San Francisco. 我们已经开发了用于picoinjecting微滴，不需要金属电极的技术。因此，结合我们的技术设备是简单的制造和使用。 

视频: Picoinjection of Microfluidic Drops Without Metal Electrodes

Fabrication and Testing of Microfluidic Optomechanical Oscillators

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained.

Parametric optomechanical excitations have recently been experimentally demonstrated in microfluidic optomechanical resonators by means of optical radiation pressure and stimulated Brillouin scattering. This paper describes the fabrication of these microfluidic resonators along with methodologies for generating and verifying optomechanical oscillations.

制造和微流控光机振荡器测试

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including ...

科研

工程学

Ultrasound Velocity Measurement in a Liquid Metal Electrode

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within &#177;2 &#176;C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries.

Ultrasound velocimetry is used to study mixing by fluid flow in liquid metal electrodes. The focus of this manuscript is to illustrate the methods used for making precise, spatially-resolved ultrasound measurements while limiting oxidation and controlling and monitoring temperature, applied current, and the heater power being supplied.

超声速度测量的液态金属电极

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently ...

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (&#181;PAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

The study demonstrates the growth of iridium oxide-reduced graphene oxide (IrO2-RGO) nanohybrid thin films on irregular and rough screen-printed carbon substrate through a green electrochemical synthesis, and their implementation as a pH sensor with a patterned paper-fluidic platform.

氧化铱还原氧化石墨烯纳米杂化薄膜修饰丝网印刷电极一次性电化学微流控纸pH传感器

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use ...

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques.
This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

The following paper presents a novel FE simulation technique (KBC-FE), which reduces computational cost by performing simulations on a cloud computing environment, through the application of individual modules. Moreover, it establishes a seamless collaborative network between world leading scientists, enabling the integration of cutting edge knowledge modules into FE simulations.

板料成形过程的知识基于云的有限元模拟

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the ...

In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films

Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs within the interlayer space of semiconducting layered titania nanosheet (TNS) films was investigated here. Two types of intermediate films (i.e., TNS films containing methyl viologen (TNS/MV2+) and 2-ammoniumethanethiol (TNS/2-AET+)) were prepared. The two intermediate films were soaked in an aqueous tetrachloroauric(III) acid (HAuCl4) solution, whereby considerable amounts of Au(III) species were accommodated within the interlayer spaces of the TNS films. The two types of obtained films were then soaked in an aqueous sodium tetrahydroborate (NaBH4) solution, whereupon the color of the films immediately changed from colorless to purple, suggesting the formation of AuNPs within the TNS interlayer. When only TNS/MV2+ was used as the intermediate film, the color of the film gradually changed from metallic purple to dusty purple within 30 min, suggesting that aggregation of AuNPs had occurred. In contrast, this color change was suppressed by using the TNS/2-AET+ intermediate film, and the AuNPs were stabilized for over 4 months, as evidenced by the characteristic extinction (absorption and scattering) band from the AuNPs.

In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films

Here, we present a protocol for the in situ synthesis of gold nanoparticles (AuNPs) within the interlayer space of layered titanate films without the aggregation of AuNPs. No spectral change was observed even after 4 months. The synthesized material has expected applications in catalysis, photo-catalysis, and the development of cost-effective plasmonic devices.

在没有聚集的层状钛酸盐薄膜透明的层间金纳米粒子的原位合成

Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs ...

Electrospinning of Photocatalytic Electrodes for Dye-sensitized Solar Cells

This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of electrospun titanium dioxide nanofibers (TiO2-NFs) on top of a blocking layer made of commercially available titanium dioxide nanoparticles (TiO2-NPs). This is achieved by first electrospinning a solution of titanium (IV) butoxide, polyvinylpyrrolidone (PVP), and glacial acetic acid in ethanol to obtain composite PVP/TiO2 nanofibers. These are then calcined at 500 &#176;C to remove the PVP and to obtain pure anatase-phase titania nanofibers. This material is characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The photoanode is prepared by first creating a blocking layer through the deposition of a TiO2-NPs/terpineol slurry on a fluorine-doped tin oxide (FTO) glass slide using doctor blading techniques. A subsequent thermal treatment is performed at 500 &#176;C. Then, the light-scattering layer is formed by depositing a TiO2-NFs/terpineol slurry on the same slide, using the same technique, and calcinating again at 500 &#176;C. The performance of the photoanode is tested by fabricating a dye-sensitized solar cell and measuring its efficiency through J-V curves under a range of incident light densities, from 0.25-1 Sun.

The overall goal of this project was to use electrospinning to fabricate a photoanode with improved performance for dye-sensitized solar cells.

染料敏化太阳能电池的光催化电极的电纺丝

This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a polymer film. This paper also presents a low-cost, vacuum-free fabrication method for this novel TE; the approach combines lithography, electroplating, and imprint transfer (LEIT) processing. The embedded nature of the EMTEs offers many advantages, such as high surface smoothness, which is essential for organic electronic device production; superior mechanical stability during bending; favorable resistance to chemicals and moisture; and strong adhesion with plastic film. LEIT fabrication features an electroplating process for vacuum-free metal deposition and is favorable for industrial mass production. Furthermore, LEIT allows for the fabrication of metal mesh with a high aspect ratio (i.e., thickness to linewidth), significantly enhancing its electrical conductance without adversely losing optical transmittance. We demonstrate several prototypes of flexible EMTEs, with sheet resistances lower than 1 &#937;/sq and transmittances greater than 90%, resulting in very high figures of merit (FoM) &#8211; up to 1.5 x 104 &#8211; which are amongst the best values in the published literature.

This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

具有嵌入式金属网的高性能，灵活，透明电极的可扩展解决方案处理制造策略

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures

The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted much attention from the oxide electronics community. One of its hallmark features is the existence of a critical LAO thickness of 4 unit-cells (uc) for interfacial conductivity to emerge. Although electrostatic mechanisms have been proposed in the past to describe the existence of this critical thickness, the importance of chemical defects has been recently accentuated. Here, we describe the growth of metal/LAO/STO heterostructures in an ultra-high vacuum (UHV) cluster system combining pulsed laser deposition (to grow the LAO), magnetron sputtering (to grow the metal) and X-ray photoelectron spectroscopy (XPS). We study step by step the formation and evolution of the q2DES and the chemical interactions that occur between the metal and the LAO/STO. Additionally, magnetotransport experiments elucidate on the transport and electronic properties of the q2DES. This systematic work not only demonstrates a way to study the electrostatic and chemical interplay between the q2DES and its environment, but also unlocks the possibility to couple multifunctional capping layers with the rich physics observed in two-dimensional electron systems, allowing the fabrication of new types of devices.

Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures

We fabricate metal/LaAlO3/SrTiO3 heterostructures using a combination of pulsed laser deposition and in situ magnetron sputtering. Through magnetotransport and in situ X-ray photoelectron spectroscopy experiments, we investigate the interplay between electrostatic and chemical phenomena of the quasi two-dimensional electron gas formed in this system.

金属/LaAlO 的生长和静电/化学性质3/SrTiO3异

The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted much attention from the oxide ...

Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in industry. The wettability of the produced surface was analyzed by bouncing drop experiments and the topography was analyzed by confocal microscopy. In addition, we show various methodologies to measure its durability and anti-icing properties. Superhydrophobic surfaces hold a special texture that must be preserved to keep their water-repellency. To fabricate durable surfaces, we followed two strategies to incorporate a resistant texture. The first strategy is a direct incorporation of roughness to the metal substrate by acid etching. After this surface texturization, the surface energy was decreased by silanization or fluoropolymer deposition. The second strategy is the growth of a ceria layer (after surface texturization) that should enhance the surface hardness and corrosion resistance. The surface energy was decreased with a stearic acid film.
The durability of the superhydrophobic surfaces was examined by a particle impact test, mechanical wear by lateral abrasion, and UV-ozone resistance. The anti-icing properties were explored by studying the ability to repeal subcooled water, freezing delay, and ice adhesion.

We illustrate several methodologies to produce superhydrophobic metal surfaces and to explore their durability and anti-icing properties.

防结冰用超疏水性金属表面的制备

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in ...

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication FFF of Metal-Ceramic Components

This study shows multi-material additive manufacturing (AM) using fused filament fabrication (FFF) of stainless steel and zirconia.

金属陶瓷元件的熔融长丝制造 (fff)

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with ...