This work was supported by EPSRC Career Acceleration grant EP/J002402/1.

注意:使用前请咨询所有相关的材料安全数据表。在这个协议中使用的过氧化氢是有害的，并且在暴露于铂氧气的演进带来爆炸危险。该协议包括工程控制，同时处理过氧化物溶液（通风柜）和个人防护设备（防护眼镜，手套和白大褂）过程中使用的所有适当的安全控制。 1.使催化Janus粒子<ol><li> 准备搏命基板 <ol><li>使用顺序洗涤每个在去离子（DI）水，玻璃去污溶液和DI水几分钟清洁的未使用标准显微镜载玻片。乙醇V混合物:然后用70:30 v洗去离子水，最后在一个干净的空气/氮气流吹干。 </li><li>在显微镜下检查载玻片，以验证该表面距微粒污染的证据清洁无。重复步骤1.1。1，如果需要的。 </li></ol></li><li> 准备沉积胶体分散体系 <ol><li>吸移管将10μl水溶液库存荧光胶体溶液（10％重量）放入990微升乙醇。根据用于到达约0.1％（重量）的胶体悬浮液原液浓度根据需要调节卷。 </li><li>涡旋混合10秒。 </li></ol></li><li> 旋涂胶体分散到载玻片基板 <ol><li>装备用干净的玻片上旋涂机。填用100μl上面制备的稀释胶体溶液的吸移管尖。程序旋涂机以执行30秒，2000转周期。开始旋涂机，并且当加快速度连续吸取所述制备的溶液到纺丝载玻片的中心。 </li><li>从旋转涂布机中取出载玻片，回到光学显微镜和验证甚至主要是非接触不同的胶体分散覆盖中部地区ÒF中的搏命。 </li></ol></li><li> 真空蒸发铂金属胶体上装饰载玻片 <ol><li>插入胶体涂覆载玻片为金​​属蒸发器。确保胶体装饰侧朝向蒸发源。安装的铂金属蒸发源和沉积铂金属的15纳米。 注意:下面的金属沉积，样品应当存放在惰性气氛下。 </li></ol></li></ol> 2."游泳"Janus粒子<ol><li> 重新悬浮的Janus胶体成含有过氧化溶液 <ol><li>切割晶状体组织中的1×1cm的正方形，挫伤与10微升的去离子水结束。用镊子保持，并沿镀铂胶体装饰玻璃载玻片表面轻轻揉搓（此步骤在物理上从衬底移除胶体）。 </li><li>将镜头纸到1.5毫升去离子水，大力摇晃手动30秒在一个密封的涂是。取下镜头组织。 </li><li>吸管1ml含有溶液到新的容器中的胶体，填充用1ml 30％w / v的H 2 O 2的储液。轻轻混匀该溶液，然后将在室温下超声浴中5分钟，随后再25分钟未搅拌潜伏期。 注意:此解决方案可能演变的氧气;不密封。 </li><li>干燥的100微升剩余的含水胶体溶液到的扫描电子显微镜（SEM）存根使的Janus胶体结构的SEM验证。14 </li></ol></li><li> 准备分析比色皿 <ol><li>额外1毫升DI水添加到含有过氧化和镀铂胶体，以在适当的燃料强度（10％）到达，以允许快速推进的温育溶液。 注:现有孵化阶段是在浓度较高的燃料浓度的清洁铂催化剂表面进行。 </li><li>补罗W¯¯量矩形石英玻璃比色皿与培养方案。松配合推的帽子。 注意:爆炸危险 - 不使用螺丝帽。 </li></ol></li></ol> 3.显微观察<ol><li> 定位感兴趣的颗粒 <ol><li>负载反应杯到装有合适的目标（ 例如，20X）的荧光显微镜和使用的过滤器的适当组合（激发450-490纳米，发射&gt; 515纳米）激发荧光团的发射。 </li><li>手动搜索的反应杯内的荧光胶体。 注意:调节胶体密度，同时保持过氧化物浓度可能需要。例如，推荐的稀释如果胶体密度高，并产生流过大量的氧气气泡存在。约0.003％胶体体积浓度是建议起点。 </li><li>优化3D追踪光学设置:合适的光照条件下，我N对焦胶体会出现尖锐圆形物体。然而，由于推进器移动胶体进出焦平面的独特的尺寸变更周围将观察到球体中心的亮环，这是用来确定的z坐标，以使3D跟踪。 </li></ol></li><li> 录制视频 <ol><li>开始视频捕捉之前，聚焦显微镜，使得所关注的粒子产生的同心环，与颗粒"下"的聚焦位置。在视频拍摄不移动焦点平面。 </li><li>感兴趣的颗粒录制视频。使用带有超过30赫兹帧频30秒的视频时长，以便详细的弹道重建。 </li></ol></li><li> 三维轨迹重建 <ol><li> 校准Z轴 <ol><li>补2％（重量）。在60℃下，放置在含有悬浮荧光Janus粒子的水吉兰糖胶溶液中的等效反应杯至以上使用，并且允许设置以形成含有固定静态胶体刚性透明胶凝样本。 </li><li>着眼于使用上述选择的相同照明条件下单个固定胶体，现在记录一系列静止图像作为z轴焦点是通过相对于这个平面已知位移上升。 </li><li>确定在每个已知焦点位置11的环的半径。 注意:这是最有效地使用可作为间歇方法被应用到所有的校准的图像分析算法来执行静止帧和视频。一个典型的方法涉及平滑图像，阈值，以确定所述对象的中心的近似位置，然后通过测量强度峰任环的侧面之间的距离定位的实际x和环中心的y坐标。从环中心的强度的峰的平均径向距离然后可以发现11这使得亮环的两个半径D中的x​​y坐标与子像素精度来确定。通过定位的x，y和z从焦平面固定在绞兰胶30μm的两面神球体的位置，在图像的时间序列，粒子可位于与沿每个轴±25纳米的误差。该错误可以归因于在图像噪声。噪比并因此信号，的位置的算法的准确度依赖于检测到的荧光的光的强度。当的Janus球体远离焦平面其强度变得太弱准确跟踪它， 例如 ，对于一个直径4.8微米的胶体的约200的Z范围微米是可能的。另一种非算法的方法是使用X，Y中心和半径的简单手工测量，然而，这将降低准确性。 </li><li>绘制校准曲线，以涉及半径z-位置，并适合于适当的功能（ 例如 ，三次方程），以允许内插。11 </li></ol></li> &lt;李&gt; 校准X，Y轴 <ol><li>记录使用3.2选择了相同的显微镜条件下的静止画面的空间标定刻度的光学显微镜图像。 </li><li>测量与已知的真实世界大小的物体从空间校准刻度图像的"像素"的尺寸和使用它来建立一个像素微米的转换系数为X，Y图像平面。 </li></ol></li><li> 弹道重建 <ol><li>确定所述视频序列的每一帧中的x和y坐标和半径如3.3.1.3中所述，使用在3.3.1.4发现半径转换成z中的功能，和在3.3.2.2中找到的校准系数来转换x和y像素坐标到微米。此过程将导致在一个准确的x，y，z坐标的推进颗粒位置作为时间的函数。11本步骤可使用算法手动来实现，或。 </li><li>确定衍生properties诸如平均速度量化观察催化游泳的程度。 </li></ol></li></ol></li></ol>

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The authors have nothing to disclose.

在铂Janus粒子制备协议的许多因素会影响观测到的轨迹。由于使用2微米的直径的颗粒会给推进速度在每秒10微米量级描述的参数。如果使用更小的颗粒，速度会增加，同时增加粒度会降低推进速度。12蒸发协议的细节也将改变所观察到的轨迹。在当前的协议，推荐胶体的稀疏分布，以金属蒸镀垂直于滑动方向在一起。这些条件导致如在图2中，这导致布朗旋转扩散的限制范围内的线性轨迹中所示的对称的Janus结构。13相反，如果紧填充胶体受到掠射角沉积，则实现Janus帽的对称性可破，诱使旋转行为。14霸这里出产的rticles显示在所有三个维度相对各向同性的议案;然而，如果使用更厚的铂涂层，或更大的颗粒中，向上偏压或gravitaxis可以赋予。制造后的Janus胶体的存储的11详细还可以影响所观察到的游泳速度。高表面能清洁铂表面从蒸发阶段新兴易受表面污染从例如烃，特别是硫醇。15 此外，该溶液的性质，其中的Janus胶体再悬浮是用于观察推进的关键。低过氧化物浓度将导致较慢的速度，作为分解反应产生的运动的速率减少。6此外，低浓度的盐会造成在推进速度的显着降低的。7 这里生产的胶体的一个主要特点是他们的NEutral浮力，这使得它们适合3D跟踪。一般游泳装置的领域已很少关注3D效果，部分原因是由于从致密金属正在作出一些突出的例子，使它们迅速沉淀，16而且还由于与使所需的测量有关的困难和费用。对于一些建立三维跟踪方法明显的缺点，这些快速移动胶体存在，例如，共焦激光扫描显微镜可缺少的时间分辨率来记录足够数量的图像来解决轨迹。在这种情况下，我们在这里提出的方法具有只需要一个单一的框架，以允许z坐标的估计，这因此允许高帧速率的显著优势。另外，作为Z坐标的重建仅仅依赖于外的焦点的胶体在单个帧的相对对比度，而不是绝对的荧光强度，它是弹性的淬火和闪烁的效果在荧光团。这些优点是有可能在场的减少的深度在其上的3D轨迹重建是可能的费用，以及用于很好地分离非重叠胶体的要求。我们希望，描述协议将允许在3D行为的其他感兴趣的研究组供游泳设备直截了当和具有高度的精度访问此信息。很显然，扩展这些设备3D的理解将开辟性的未来的现象和应用显著范围。感兴趣的轨迹分析的进一步细节读者引向参考17，描述了在推进系统，以及如何确保推进速度的精确量化的公共构件。

催化游泳设备是小规模，能够在流体环境下自主生成运动不受限制胶体1,2这些设备正在吸引显著的研究兴趣，因为他们必须启用激动人心的新功能，如药物输送，3实验室芯片上的运输潜力4和环境整治。5一个被广泛研究的例子是催化"剑锋"游泳者。6这些粒子由两种不同的两侧，或面（剑锋是一个两面对罗马神）得到他们的名字。一面是催化活性的，并且能够进行分解反应，而另一种是惰性的。在合适的溶解燃料分子的存在，所产生的不对称化学反应产生在其周围可以产生经由自diffusiophoresis /电泳运动的胶体梯度。7 表征为这些快速移动的物体的运动是茶<html> llenging和许多实验观察到迄今被限制在二维。然而，最终的应用很可能利用催化游泳设备在整个大宗解决方案在3D能力。8要解决这个问题，在这里我们描述了一个协议，允许被确定游泳设备精确的三维轨迹。此方法是基于解释由出具有固定焦点物镜，9观察焦点荧光胶体制备的环结构，并且易于使用常规未修改显微镜适用。这里所描述清楚这种方法，在这一领域的其他研究人员将能够访问这些3D信息中获益。这将有助于未来的见解运动特性游泳设备。这种潜在的证据是由最近的游泳设备报告给被定向在重力作用下，10,11行为，可以非常容易地通过3D追踪的应用可视化。11 ove_content"&gt;本文还清楚地记录了制造催化剑锋颗粒游泳设备，这将是进一步受益规范跨越现有的研究小组调查这些设备的方法，并且还引导热衷于制造和调查游泳设备的新的研究方法。

<table border="0" cellpadding="0" cellspacing="0" width="877">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Evaporator</td>
			<td style="width:153px;">Moorfield (UK)</td>
			<td style="width:119px;"></td>
			<td style="width:359px;">Minilab 80 e-beam evaporator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microscope</td>
			<td>Nikon</td>
			<td style="width:119px;"></td>
			<td>Eclipse LV100</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Fluorescence light source</td>
			<td>Nikon</td>
			<td></td>
			<td>Nikon B2A filter cube</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Objective</td>
			<td>Nikon</td>
			<td></td>
			<td>x20, 0.45 NA</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cuvette</td>
			<td>Hellma</td>
			<td></td>
			<td>fused quartz, 40 x 10 x 1 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Vortex mixer</td>
			<td style="width:153px;">IKA</td>
			<td></td>
			<td>Lab Dancer S2</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Spin coater</td>
			<td style="width:153px;">Laurell Technologies Corp.</td>
			<td></td>
			<td>Model WS-400BZ-6NPP/Lite</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Ultrasonic bath</td>
			<td style="width:153px;">Eumax</td>
			<td style="width:119px;"></td>
			<td>2 litre</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lens tissue</td>
			<td>Whatman</td>
			<td style="width:119px;">2105 841</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrogen Peroxide</td>
			<td>Sigma-Aldrich</td>
			<td style="width:119px;">31642-1L</td>
			<td>30 wt%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Platinum</td>
			<td>Sigma-Aldrich</td>
			<td align="right" style="width:119px;">267171</td>
			<td>0.25 mm, 99.99%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Colloids</td>
			<td style="width:153px;">Thermo Scientific</td>
			<td style="width:119px;"></td>
			<td>Fluoro-Max PS microspheres, d= 1.9 microns</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Glass decontamination solution</td>
			<td style="width:153px;">Fisher Scientific</td>
			<td>D/0025/15</td>
			<td style="width:359px;">Decon 90</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Ethanol</td>
			<td style="width:153px;">Fisher Scientific</td>
			<td style="width:119px;">E/0600DF/17</td>
			<td>Absolute Ethanol</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">DI water</td>
			<td style="width:153px;">Elga</td>
			<td style="width:119px;"></td>
			<td>Purelab Option filtration system (15 MW)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Gellan gum</td>
			<td style="width:153px;">Sigma-Aldrich</td>
			<td style="width:119px;">P8169-100G</td>
			<td>&#34;Phytagel&#34;</td>
		</tr>
	</tbody>
</table>

preparation and 3d tracking of catalytic swimming devices

We report a method to prepare catalytically active Janus colloids that "swim" in fluids and describe how to determine their 3D motion using fluorescence microscopy. One commonly deployed method for catalytically active colloids to produce enhanced motion is via an asymmetrical distribution of catalyst. Here this is achieved by spin coating a dispersed layer of fluorescent polymeric colloids onto a flat planar substrate, and then using directional platinum vapor deposition to half coat the exposed colloid surface, making a two faced "Janus" structure. The Janus colloids are then re-suspended from the planar substrate into an aqueous solution containing hydrogen peroxide. Hydrogen peroxide serves as a fuel for the platinum catalyst, which is decomposed into water and oxygen, but only on one side of the colloid. The asymmetry results in gradients that produce enhanced motion, or "swimming". A fluorescence microscope, together with a video camera is used to record the motion of individual colloids. The center of the fluorescent emission is found using image analysis to provide an x and y coordinate for each frame of the video. While keeping the microscope focal position fixed, the fluorescence emission from the colloid produces a characteristic concentric ring pattern which is subject to image analysis to determine the particles relative z position. In this way 3D trajectories for the swimming colloid are obtained, allowing swimming velocity to be accurately measured, and physical phenomena such as gravitaxis, which may bias the colloids motion to be detected.

图1示出胶体上之前沉积铂干净的载玻片上的典型的分散; 图2示出了用于涂敷的Janus游泳半铂典型背散射SEM图像，在该成像模式的铂涂覆的区域产生了鲜明的对比。所需的半球形铂层是显而易见的。 图3显示了典型的荧光的Janus游泳者的固定在绞兰胶最佳照明条件下的外观。游泳者显示为对称的环的功能，而且它是一个可以被用来确定所述胶体相对于聚焦位置的z位置的环的半径。 图4示出了代表的横截面的径向亮度强度分布在组合使用图像分析算法来准确定位中心和胶体的表观半径。 图5 </stron<html> g&gt;的包含使用一个固定的胶体样品和校准显微镜z轴平移阶段涉及从焦点位置表观胶体尺寸和距离而获得的校正曲线。此曲线被装配到一个三次函数，这是用来表观半径转换为z坐标。最后， 图6显示一个典型的x，y，为荧光的Janus粒子游泳ž轨迹。 <img alt="图1" src="/files/ftp_upload/54247/54247fig1.jpg" /> 图1. 直径1.9微米的聚苯乙烯微光学图像。微球分散在铂金沉积之前清洁的载玻片。比例尺代表40微米。 <a href="https://www.jove.com/files/ftp_upload/54247/54247fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> ES / ftp_upload / 54247 / 54247fig2.jpg"/&gt; 图2. 直径为1.9微米的聚苯乙烯微球的SEM背散射图像。在微铂沉积后显示。比例尺代表2微米。 <a href="https://www.jove.com/files/ftp_upload/54247/54247fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54247/54247fig3.jpg" /> 图3. 固定在使用20X物镜（0.4 NA）的记录，吉兰糖胶的直径4.8微米的荧光聚苯乙烯球的校准图像。每个图像下面的距离表明球体上述物镜的焦平面的距离。作为图像从0到200微米的一个明亮的光盘变为亮环的聚焦图像散焦，在半径为依赖于放大率时，spherE尺寸和焦平面的距离。 <a href="https://www.jove.com/files/ftp_upload/54247/54247fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54247/54247fig4.jpg" /> 图4 的X，Y，Z粒子跟踪过程。一组自写的算法被用来通过提取一系列垂直线和水平线，并找到平均值中期首先找到亮环的（X，Y）中心亮峰之间的点（A）。环半径然后从安装到平均像素灰度值从环中心（B型）辐射出样条曲线的峰值强度计算。 <a href="https://www.jove.com/files/ftp_upload/54247/54247fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 图5的Z坐标校准图表用于通过测量固定在绞兰胶球的亮环的半径获得的Janus球体（参见图3和4），校准图表用于由我们的算法，以测得的环半径转换为Z-坐标。 <a href="https://www.jove.com/files/ftp_upload/54247/54247fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图6" src="/files/ftp_upload/54247/54247fig6.jpg" /> 图6. 典型荧光的Janus球体游泳装置的轨迹。移动游泳装置的图像的序列在33赫兹的帧频被记录在一段30秒。通过定位亮环中心得到的轨迹（X，Y，Z）坐标（FI古尔图4（a））和比较测量圈半径校准图表序列中的每个图像（ 图4（b）和5）。 <a href="https://www.jove.com/files/ftp_upload/54247/54247fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Preparation and 3D Tracking of Catalytic Swimming Devices at JoVE.com

Preparation and 3D Tracking of Catalytic Swimming Devices

A method to prepare catalytically active Janus colloids that can "swim" in fluids and determine their 3D trajectories is presented.

催化游泳器件的制备及其三维跟踪

We report a method to prepare catalytically active Janus colloids that "swim" in fluids and describe how to determine their 3D motion using fluorescence ...

preparation-and-3d-tracking-of-catalytic-swimming-devices

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Unit 1

Motion in Two or Three Dimensions

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7.5K 次观看.  University of Sheffield. A method to prepare catalytically active Janus colloids that can "swim" in fluids and determine their 3D trajectories is presented.

视频: Preparation and 3D Tracking of Catalytic Swimming Devices

High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses triangulation between matching points in two views of the same scene at different angles to compute depth.&#160;However, unlike a stereo-based method, DFP uses a digital video projector to replace one of the cameras1. The projector rapidly projects a known sinusoidal pattern onto the subject, and the surface of the subject distorts these patterns in the camera&#8217;s field of view. Three distorted patterns (fringe images) from the camera can be used to compute the depth using triangulation.
Unlike other 3D measurement methods, DFP techniques lead to systems that tend to be faster, lower in equipment cost, more flexible, and easier to develop.&#160;DFP systems can also achieve the same measurement resolution as the camera.&#160;For this reason, DFP and other digital structured light techniques have recently been the focus of intense research (as summarized in1-5). Taking advantage of DFP, the graphics processing unit, and optimized algorithms, we have developed a system capable of 30&#160;Hz 3D video data acquisition, reconstruction, and display for over 300,000 measurement points per frame6,7.&#160;Binary defocusing DFP methods can achieve even greater speeds8.
Diverse applications can benefit from DFP techniques. Our collaborators have used our systems for facial function analysis9, facial animation10, cardiac mechanics studies11, and fluid surface measurements, but many other potential applications exist.&#160;This video will teach the fundamentals of DFP techniques and illustrate the design and operation of a binary defocusing DFP system.

This video describes the fundamentals of digital fringe projection techniques, which provide dense 3D measurements of dynamically changing surfaces.&#160;It also demonstrates the design and operation of a high-speed binary defocusing system based on these techniques.

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses ...

科研

工程学

Analysis of Contact Interfaces for Single GaN Nanowire Devices

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit a strong degradation after annealing due to the occurrence of void formation at the contact/SiO2 interface. This void formation can cause cracking and delamination of the metal film, which can increase the resistance or lead to a complete failure of the NW device. In order to address issues associated with void formation, a technique was developed that removes Ni/Au contact metal films from the substrates to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN NW devices. This procedure determines the degree of adhesion of the contact films to the substrate and NWs and allows for the characterization of the morphology and composition of the contact interface with the substrate and nanowires. This technique is also useful for assessing the amount of residual contamination that remains from the NW suspension and from photolithographic processes on the NW-SiO2 surface prior to metal deposition. The detailed steps of this procedure are presented for the removal of annealed Ni/Au contacts to Mg-doped GaN NWs on a SiO2 substrate.

A technique was developed that removes Ni/Au contact metal films from their substrate to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN nanowire devices.

单氮化镓纳米线设备分析接触界面

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit  a strong degradation after annealing due to the  occurrence of void formation at the ...

Preparation and Reactivity of Gasless Nanostructured Energetic Materials

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic&#160;composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.

This protocol describes the preparation of gasless nanostructured energetic materials (Ni+Al, Ta+C, Ti+C) using the short-term high-energy ball milling (HEBM) technique. It also describes a high-speed thermal imaging method to study the reactivity of mechanically fabricated nanocomposites. These protocols can be extended to other reactive nanostructured energetic materials.

准备和无气腹纳米结构的反应含能材料

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the ...

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.

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. ...

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

Acoustofluidic devices use ultrasonic waves within microfluidic channels to manipulate, concentrate and isolate suspended micro and nanoscopic entities. This protocol describes the fabrication and operation of such a device supporting bulk acoustic standing waves to focus particles in a central streamline without the aid of sheath fluids.

制造和Acoustofluidic设备的运营支撑体声波驻波的聚焦鞘颗粒

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must ...

Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal inks. For the photoactive absorber layer, colloidal CdTe and CdSe nanocrystals (3-5 nm) are synthesized using an inert hot injection technique and cleaned with precipitations to remove excess starting reagents. Similarly, gold nanocrystals (3-5 nm) are synthesized under ambient conditions and dissolved in organic solvents. In addition, precursor solutions for transparent conductive indium tin oxide (ITO) films are prepared from solutions of indium and tin salts paired with a reactive oxidizer. Layer-by-layer, these solutions are deposited onto a glass substrate following annealing (200-400 &#176;C) to build the nanocrystal solar cell (glass/ITO/CdSe/CdTe/Au). Pre-annealing ligand exchange is required for CdSe and CdTe nanocrystals where films are dipped in NH4Cl:methanol to replace long-chain native ligands with small inorganic Cl- anions. NH4Cl(s) was found to act as a catalyst for the sintering reaction (as a non-toxic alternative to the conventional CdCl2(s) treatment) leading to grain growth (136&#177;39 nm) during heating. The thickness and roughness of the prepared films are characterized with SEM and optical profilometry. FTIR is used to determine the degree of ligand exchange prior to sintering, and XRD is used to verify the crystallinity and phase of each material. UV/Vis spectra show high visible light transmission through the ITO layer and a red shift in the absorbance of the cadmium chalcogenide nanocrystals after thermal annealing. Current-voltage curves of completed devices are measured under simulated one sun illumination. Small differences in deposition techniques and reagents employed during ligand exchange have been shown to have a profound influence on the device properties. Here, we examine the effects of chemical (sintering and ligand exchange agents) and physical treatments (solution concentration, spray-pressure, annealing time and annealing temperature) on photovoltaic device performance.

This protocol describes the synthesis and solution deposition of inorganic nanocrystals layer by layer to produce thin film electronics on non-conductive surfaces. Solvent-stabilized inks can produce complete photovoltaic devices on glass substrates via spin and spray coating following post-deposition ligand exchange and sintering.

全面解决方案处理的无机纳米晶体光伏器件的制造

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal ...

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 ...

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360&#176; rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.

Scanning Light Scattering Profiler SLPS Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

This protocol describes the scanning light scattering profiler (SLSP) that enables the full-angle quantitative evaluation of forward and backward scattering of light from intraocular lenses (IOLs) using goniophotometer principles.

基于扫描光散射分析器（SLPS）的方法来量化评估来自眼内镜的前向和后向光散射

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light ...

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

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems.
The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.

The goal of the protocol is to create liquid crystalline polymer films that can mechanically oscillate under continuous light irradiation. We describe in great detail the conception of free-standing films, from the liquid crystal alignment method to the photo-actuation. The experimental protocol applied to prepare this material is broadly applicable.

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 ...

Fabrication of Refractive-index-matched Devices for Biomedical Microfluidics

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices can be implemented as part of a robust platform capable of making simultaneous complementary measurements. The primary challenge created by the combination of these two techniques is the mismatch in refractive index between the materials traditionally used to make microfluidic devices and the aqueous solutions typically used in biomedicine. This mismatch can create optical artifacts near the channel or device edges. One solution is to reduce the refractive index of the material used to fabricate the device by using a fluorinated polymer such as MY133-V2000 whose refractive index is similar to that of water (n = 1.33). Here, the construction of a microfluidic device made out of MY133-V2000 using soft lithography techniques is demonstrated, using O2 plasma in conjunction with an acrylic holder to increase the adhesion between the MY133-V2000 fabricated device and the polydimethylsiloxane (PDMS) substrate. The device is then tested by incubating it filled with cell culture media for 24 h to demonstrate the ability of the device to maintain cell culture conditions during the course of a typical imaging experiment. Finally, quantitative phase microscopy (QPM) is used to measure the distribution of mass within the live adherent cells in the microchannel. This way, the increased precision, enabled by fabricating the device from a low index of refraction polymer such as MY133-V2000 in lieu of traditional soft lithography materials such as PDMS, is demonstrated. Overall, this approach for fabricating microfluidic devices can be readily integrated into existing soft lithography workflows in order to reduce optical artifacts and increase measurement precision.

This protocol describes the fabrication of microfluidic devices from MY133-V2000 to eliminate artifacts that often arise in microchannels due to the mismatching refractive indices between microchannel structures and an aqueous solution. This protocol uses an acrylic holder to compress the encapsulated device, improving adhesion both chemically and mechanically.

生物医学微流体折射率匹配器件的研制

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices ...