感谢M.勒伯夫为阳极质感的铝主站和瑞士联邦能源办公室和瑞士国家科学基金会提供资金援助的原子力显微镜（AFM），W.李。 FP7项目资助的"快速通道"，由欧盟委员会资助协议没有283501的框架中进行这项工作的一部分。

1。模具制造我们用我们自制的纳米印刷设置，用于制造模具的负面以下参考。6，但奈米压印任何其他设置将正常工作。另外一种官能化的聚二甲基硅氧烷（PDMS）模具也可能会工作。 <ol><li>制造或购买一个合适的主承载的纳米级图案被转移。原则上，任何掌握合适的纳米压印将做的工作。我们使用有纹理的ZnO层的玻璃板上（肖特，AF32生态41毫米×41毫米×0.5毫米），沉积为3.1中描述的作为一个主结构，说明了该方法。 </li><li>应用2中所述的主结构上的防粘附层。 </li><li>清洁的聚萘二甲酸（PEN）的片材（古德费洛82毫米×41毫米×0.125毫米），在超声波丙酮浴中2分钟，然后通过超声波异丙醇浴2更多分钟。再次用异丙醇冲洗，并用氮气吹干。 </li><li>存款一溅镀铬的粘附层（5-10 nm）的的PEN表上。 </li><li>旋涂紫外线固化型树脂（Microresist，ORMOCER 1-2毫升）在5,000 rpm的PEN片，以得到均匀的覆盖。 </li><li>执行预烘5分钟，用热板在80℃下使溶剂蒸发，提高膜的均匀性和密合性的PEN片材。 </li><li>使用您的的奈米压印设置，邮票主图案的UV固化树脂。尽管不是强制性的，我们进行冲压下真空，以防止气泡的夹杂物，通过施加到一个灵活的硅膜的均匀的压力为1巴（bar）。在我们的设置中，硅酮膜分隔成两个子隔室的真空室。的压力所产生的排气的上部隔室，而下部隔室保持在真空下。放空启动冲压朝下方推压的柔性膜。 </li><li>暴露于UV光的树脂挑起的树脂的交联反应。我们采用温和的光1.4毫瓦/厘米2的强度在波长365nm的所提供的数个LED。通过PEN片的曝光时间通常是15-20分钟。 </li><li>小心通过手动剥离了主结构的模具脱模。 </li><li>作为树脂很可能会经历轻微的功能材料的沉积过程中的收缩率，这可能会导致自发脱皮，我们执行一个温和的热后烘烤，在150℃与周围气氛的烘箱中在进一步处理之前的6-8小时期间。 </li></ol> 2。防粘连层对于成功的脱模，防粘连层，必须适应的材料和图案粗糙度。一般粗糙的模式需要低粘系数。低粘系数在光滑的图案，可能会导致从模具中剥离的功能性材料。高的粘附系数粗糙的图案，可能会导致作为adheren在模具制作过程中的PEN片材剥离的树脂从ce的树脂到主强。 <ol><li>涂在模具（或主）与溅射的铬层（5-10纳米）促进的抗粘附剂的粘附。对于平滑的模式，我们放弃这一步。在某些情况下的铬层可以防止蚀刻的主结构的防粘连剂。 </li><li>应用一小滴在玻片上抗粘连剂（Sigma-Aldrich公司（1H，1H，2H，2H-全氟辛基）trichlorsilane）。将载玻片与模具一起放入真空室，并抽空。防粘连剂会蒸发并沉积在模具上的分子单层。 </li><li>锚的抗粘连剂，通过在80℃下1-2小时期间退火</li></ol> 3。材料沉积我们在这里展示适合的材料沉积沉积技术来说明nanomoulding的多功能性。其他沉积技术也可能被应用。第三个例子说明发brication的一个完整的薄膜硅太阳能电池。 <ol><li>化学气相沉积（CVD）氧化锌:将模具上的CVD反应器中的加热板加热至180℃。使用一个金属框架，以避免弯曲的的PEN模具中锌沉积。关闭反应器，泵和，允许热化。承认前体气体（H 2 O（C 2 H 5）2锌）。此外，我们使用兴奋剂的剂量少量的B 2 H 6。的ZnO层的厚度是沉积时间成正比。我们使用的氧化锌层厚度一般为1-5微米。典型的沉积参数详细信息可在文献中找到。7 </li><li>物理气相沉积（PVD）/溅射银:将模具PVD系统。关闭系统和泵下来。承认氩处理气体。打开直流发电机。的Ag层的厚度又是沉积时间成正比。我们使用的Ag层的厚度通常为1微米。典型的沉积parameters是氩气5.5×10 -3毫巴的压力和设置特定的DC功率为250瓦，得到约45 nm /秒的沉积速率。 </li><li>等离子体增强化学气相沉积（PE-CVD）:ZnO为3.1的存款）。将模具放入的PE-CVD反应器中，加热至200℃。关闭反应器，泵和，允许热化。承认的前体气体（SiH 4和H 2）。此外，我们剂量少量的B（CH 3）3和PH 3分别实现p-型和n-型掺杂。要增加的太阳能电池的开路电压，我们还可以使用少量的CH 4和CO 2的掺杂层。销无定形硅太阳能电池堆的沉积后，我们沉积的ZnO backcontact，如在3.1中描述。 </li><li>避免过大的弯曲的模具，弯曲可能会导致沉积的层的剥离。 </li></ol> 4。层转移我们使用GLAS滑梯（肖特AF32生态，41毫米×41毫米×0.5毫米），最终基板。但是，其它基质上，包括金属箔或聚合物片材，可交替使用。 <ol><li>清洁程度载玻片用丙酮和异丙醇，并用氮气吹干。 </li><li>旋涂紫外线固化型树脂（Microresist，ORMOCER 1-2毫升）在5,000 rpm下在载玻片上。 </li><li>使用您的奈米压印设置固定的模具进行最终基板上沉积层。至于冲压，我们进行锚定在真空条件下，应用均质压力为1巴（bar）。 </li><li>公开树脂，UV光引发交联反应。我们应用一个中等强度的1.4毫瓦/厘米2，在波长为365nm的由数个LED提供。透过玻璃载片上的曝光时间是由于较高的紫外线的透射的玻璃相比，PEN，只有1-3分钟。 </li><li>通过手动关闭载玻片上剥离模具脱模。 </li></ol> 5。样品表征<ol&gt; <li>使用您最喜爱的形态，电接口或光接口技术，的特点nanomoulded的样品。在这里，我们描述我们nanomoulded的样本，利用扫描电子显微镜（SEM）和原子力显微镜（AFM）。 </li></ol>

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没有利益冲突的声明。

Nanomoulding允许传输​​任意功能材料的奈米结构。在图1和图2中的各个处理步骤的比较揭示之间的密切关系nanomoulding和纳米压印。 nanomoulding和纳米压印之间的主要差别是额外的材料沉积在图2e中的步骤。其它的处理流程是一样的。因此，可以在任何可用的纳米压印设置执行nanomoulding。 但选择兼容的模具的材料和防粘连剂，可以进行材料沉积使用各种方法，如化学和物理气相沉积技术，热蒸发家庭，而且还基于解决方案的沉积方法。相应地是宽的范围内的材料，可以nanomoulded。虽然纳米压印到可变形的聚合物进行，nanomoulding也可以是施加到硬盘诸如ZnO辔材料。此外，而常见的纳米压印树脂绝缘，导电材料可以被图案化。 对于达到升高的温度下的沉积技术，用作模支承的PEN片可以被替换由一个高性能的聚酰亚胺片材（如杜邦公司的Kapton PV9202支持的温度高达500℃）。高温纳米压印树脂也已开发承受的温度高达600℃12。 我们nanomoulding技术的一个主要优点是，该材料可沉积到模具的固体膜。基于溶胶-凝胶印迹或模塑8，9的技术，其中的功能性材料的前体在溶剂中稀释，相比，我们nanomoulding的方法避免了与如收缩和形成气孔的溶剂挥发，固化和煅烧的典型问题，气泡和裂缝。 后物质沉积，弹性模必须小心处理，以防止裂纹的形成或局部剥落的材料。的PEN片材的厚度可以调整，以避免意外的弯曲形成裂纹的临界曲率半径的模具超出。然而，一定的模具的灵活性所需的脱模过程。 氧化锌，在这项研究中通过CVD沉积导致高保真度的主图案的复制图3a给出作为生长的ZnO主纹理的SEM图像。在图3d中示出的相应nanomoulded副本。 图3g和 j的主目录和副本氧化锌结构的原子力显微镜图像的高度和角度直方图提取几乎一致，并且确认高保真。角度柱状图，这是要敏感得多比高度直方图的微妙的形态学变化，表现出作为光转向低角度的副本。也观察到这种趋势对于其他两个测试结构和表示轻微的平滑化的功能。不过，即使是很精致的细节，细如真正的晶体位错线沿面的ZnO金字塔具有精度高，均转载给出一个粗略的想法我们nanomoulding技术的分辨能力。精细调制沿边缘线光栅图3b中也可见在副本中的图3e。虽然占主导地位的形态特征是很好的再现的凹坑图案，只有被复制在图3f的尖端，在图3c中的域边界发生的发病。图案逼真，分辨率都依赖于沉积物质。初步测试nanomoulded银薄膜，溅射沉积，再现了主要的形态特征，但导致低得多的保真度和共振lution。 可达到的宽高比取决于上的沉积技术。的CVD氧化锌可以很容易统一的高宽比。对于上述统一的高宽比，在山谷中的结构易制毒化学气体耗尽会导致更快的增长速度之上，最终导致在阴影和可能列入腔结构。这些空腔的风险，并可能导致损害的机械完整性的​​电影打破的电影在脱模。最近在参考使用水溶性模具，这些问题是可以避免的。 10，传递模塑法的上下文中。 正如在介绍中提到的，nanomoulding也可以用于图案复合层堆栈和全设备。在文献。 11我们结合通过CVD法沉积的ZnO与一个完整的薄膜硅太阳能电池由PE-CVD沉积和其最终衬底上转移完整的太阳能电池。

Nanopatterning在纳米技术和应用科学的许多领域获得了巨大的重要性。模式的产生是第一步，可以通过自顶向下的方法，如基于自组装纳米球光刻技术或嵌段共聚物光刻1的方法，如电子束光刻或自底向上的方法。同样重要的模式生成模式的复制。除了 ​​光刻技术，纳米压印（ 图1）已经成为一个有前途的替代，特别适合大面积高通量的纳米级图案以较低的成本2-4。光刻需要有图案的面具，的奈米压印依赖于一个预制的主结构。通常执行从主图案转印到热塑性或紫外线或热固化性聚合物。然而，有许多情况下，它是优选直接的功能性材料上的图案转移。 &lt;P类="jove_content"&gt;在这里，我们描述了一种复制方法的基础上nanomoulding和传输层（ 图2），我们最近推出的楼盘。转移功能氧化锌电极上的纳米级图案。我们的方法可以很容易地实现nanomoulding，如果纳米压印设置是可用的。 nanomoulding提供了潜在的被推广到许多其他的功能性材料，材料堆和甚至完整的设备，提供模具材料是这样选择的，它是兼容的材料沉积过程（es）。作为一个例子我们在座的nanomoulding的透明导电氧化锌（ZnO）电极沉积化学气相沉积（CVD），找到自己的应用程序，以提高太阳能电池陷光在5。

<table border="1"><tbody><tr><td> 的试剂的名称 </td><td> 公司 </td><td> 目录编号 </td><td> 评论（可选） </td></tr><tr><td>奈米树脂</td><td> Microresist </td><td> Ormostamp </td><td></td></tr><tr><td> （1H，1H，2H，2H-Perfluoroctyl）-trichlorsilane的，防粘连剂</td><td> Sigma Aldrich公司</td><td> 448931-10G </td><td></td></tr><tr><td>载玻片</td><td>肖特</td><td> AF32生态</td><td> 0.5毫米</td></tr><tr><td>聚萘（PEN）表</td><td>古德费洛</td><td> ES361090 </td><td> 0.125毫米</td></tr><tr><td> （C 2 H 5）2 Zn的</td><td>阿克苏诺贝尔</td><td></td><td></td></tr><tr><td>银溅射靶4N </td><td>贺利氏</td><td> 81062165 </td><td></td></tr><tr><td> B 2 H 6，的SiH 4，H 2，B（CH 3）3，PH 3，CH 4，CO 2的 </td><td>梅塞尔</td><td></td><td></td></tr><tr><td></td><td></td><td></td><td> 设备 </td></tr><tr><td>奈米系统</td><td>首页 - 建</td><td></td><td></td></tr><tr><td> LP-CVD系统</td><td>首页 - 建</td><td></td><td></td></tr><tr><td> PVD系统</td><td>莱宝</td><td>非光滑450 B </td><td></td></tr><tr><td> PE-CVD反应器</td><td> Indeotec </td><td>八达通我</td><td></td></tr><tr><td> SEM </td><td> JEOL </td><td> JSM-7500 TFE </td><td></td></tr><tr><td> AFM </td><td>数显仪表</td><td>奈米级3100 </td><td></td></tr></tbody></table>

nanomoulding of functional materials, a versatile complementary pattern replication method to nanoimprinting

我们描述了nanomoulding的技术，它允许低成本的纳米级图案的功能材料，材料栈和完整的设备。 Nanomoulding层转移相结合，使任意曲面的复制模式，从主结构上的功能性材料。 nanomoulding上可以执行任何纳米压印设置，并可以适用于范围广泛的材料和沉积过程。特别是，我们表明的图案化的透明氧化锌电极的制造的光捕集在太阳能电池中的应用。

<html> 图3总结了一些nanomoulded结构的说明性实例。甲玻璃上通过CVD法生长的氧化锌主结构（a）中所示。 nanomoulded的ZnO副本的相应的（d）所示。比较高保真的nanomoulding过程中的局部高度（g）及的角度（J）直方图从AFM图像中提取透露。类似的结果显示为一个一维光栅干涉光刻（B，E，H，K）和阳极质感的铝（C，F，I，L）制成。 <img src="/files/ftp_upload/50177/50177fig1.jpg" alt="图1" fo:content-width="5in" fo:src="/files/ftp_upload/50177/50177fig1highres.jpg"/> 图1。标准纳米压印负邮票制作（广告）和纳米压印过程（诶）组成的方法。 77fig2.jpg"ALT ="图2"佛:内容宽度="5英寸的"佛:SRC ="/ files/ftp_upload/50177/50177fig2highres.jpg"/&gt; 图2。Nanomoulding负模具制造（广告），沉积的功能材料（e）组成的，锚定到最终衬底（fg）重的方法。请注意，nanomoulding过程概念上类似于图1中的纳米压印过程的额外材料的沉积步骤（e）除外。 <img src="/files/ftp_upload/50177/50177fig3.jpg" alt="图3" fo:content-width="6in" fo:src="/files/ftp_upload/50177/50177fig3highres.jpg"/> 图（3）得到的有代表性的结果由nanomoulding:AFM图像在插图中的三个主测试结构nanomoulding:ZnO的生长，通过CVD（a）中，光栅干涉光刻制造的SEM图像（b）中，通过以下方式获得的铝的阳极氧化的凹坑阵列（c）所示。该corresponding nanomoulded ZnO的副本（自由度）所示。当地高度的保真度分析比较（GI）和主目录和副本结构的角度（JL）直方图（黑色实线表示的主人，红色虚线线的副本）。 图3a中的比例尺为图3b-F包括所有的AFM插图也是有效的。

Watch this Scientific Journal Video about Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting at JoVE.com

Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting

我们描述了nanomoulding的技术，它允许低成本的纳米级图案的功能材料，材料栈和完整的设备。 nanomoulding上可以执行任何纳米压印设置，并可以适用于范围广泛的材料和沉积过程。

Nanomoulding功能材料，灵活的互补模式的复制方法，以奈米

We describe a nanomoulding technique which  allows low-cost nanoscale patterning of functional materials, materials stacks  and full devices. Nanomoulding ...

nanomoulding-functional-materials-versatile-complementary-pattern

Nanyang Technological University

Research

JoVE Journal

Engineering

11.6K 次观看.  Ecole Polytechnique Fédérale de Lausanne (EPFL). 我们描述了nanomoulding的技术，它允许低成本的纳米级图案的功能材料，材料栈和完整的设备。 nanomoulding上可以执行任何纳米压印设置，并可以适用于范围广泛的材料和沉积过程。

视频: Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting

Using Neutron Spin Echo Resolved Grazing Incidence Scattering to Investigate Organic Solar Cell Materials

The spin echo resolved grazing incidence scattering (SERGIS) technique has been used to probe the length-scales associated with irregularly shaped crystallites. Neutrons are passed through two well defined regions of magnetic field; one before and one after the sample. The two magnetic field regions have opposite polarity and are tuned such that neutrons travelling through both regions, without being perturbed, will undergo the same number of precessions in opposing directions. In this case the neutron precession in the second arm is said to &#34;echo&#34; the first, and the original polarization of the beam is preserved. If the neutron interacts with a sample and scatters elastically the path through the second arm is not the same as the first and the original polarization is not recovered. Depolarization of the neutron beam is a highly sensitive probe at very small angles (&#60;50&#160;&#956;rad) but still allows a high intensity, divergent beam to be used. The decrease in polarization of the beam reflected from the sample as compared to that from the reference sample can be directly related to structure within the sample.
In comparison to scattering observed in neutron reflection measurements the SERGIS signals are often weak and are unlikely to be observed if the in-plane structures within the sample under investigation are dilute, disordered, small in size and polydisperse or the neutron scattering contrast is low. Therefore, good results will most likely be obtained using the SERGIS technique if the sample being measured consist of thin films on a flat substrate and contain scattering features that contains a high density of moderately sized features (30 nm to 5 &#181;m) which scatter neutrons strongly or the features are arranged on a lattice. An advantage of the SERGIS technique is that it can probe structures in the plane of the sample.

Progress has been made in utilizing spin echo resolved grazing incidence scattering (SERGIS) as a neutron scattering technique to probe the length-scales in irregular samples. Crystallites of [6,6]-phenyl-C61-butyric acid methyl ester have been probed using the SERGIS technique and the results confirmed by optical and atomic force microscopy.

使用中子自旋回声解决放牧发生率散射调查有机太阳能电池材料

The spin echo resolved grazing incidence scattering (SERGIS) technique has been used to probe the length-scales associated with irregularly shaped ...

科研

工程学

Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many cases validated experimentally, for light weight or impact energy absorbing structures, as high surface area heat exchangers or electrodes, as implants to the body, and many more. Although great progress has been made in understanding their structure-properties relationships, the large number of different processing techniques, each producing material with different characteristics and structure, means that understanding of the individual effects of all aspects of structure is not complete. The replication process, where molten metal is infiltrated between grains of a removable preform material, allows a markedly high degree of control and has been used to good effect to elucidate some of these relationships. Nevertheless, the process has many steps that are dependent on individual &#8220;know-how&#8221;, and this paper aims to provide a detailed description of all stages of one embodiment of this processing method, using materials and equipment that would be relatively easy to set up in a research environment. The goal of this protocol and its variants is to produce metal foams in an effective and simple way, giving the possibility to tailor the outcome of the samples by modifying certain steps within the process. By following this, open cell aluminum foams with pore sizes of 1&#8211;2.36 mm diameter and 61% to 77% porosity can be obtained.

Replication is one of the processing techniques used for the production of porous metal sponges. In this paper one implementation of the method for the production of open celled porous aluminum is shown in detail.

铸造协议的开孔泡沫铝通过复制技术的生产和孔隙率的影响

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many ...

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 ...

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial resolution, and is even capable of providing atomically resolved elemental maps. In this technique, a highly focused electron beam is incident upon a thin sample and the energy of emitted X-rays is measured in order to determine the atomic species of material within the beam path. This elementally sensitive spectroscopy technique can be extended to three dimensional tomographic imaging by acquiring multiple spectrum images with the sample tilted along an axis perpendicular to the electron beam direction.
Elemental distributions within single nanoparticles are often important for determining their optical, catalytic and magnetic properties. Techniques such as X-ray tomography and slice and view energy dispersive X-ray mapping in the scanning electron microscope provide elementally sensitive three dimensional imaging but are typically limited to spatial resolutions of &gt; 20 nm. Atom probe tomography provides near atomic resolution but preparing nanoparticle samples for atom probe analysis is often challenging. Thus, elementally sensitive techniques applied within the scanning transmission electron microscope are uniquely placed to study elemental distributions within nanoparticles of dimensions 10-100 nm.
Here, energy dispersive X-ray (EDX) spectroscopy within the STEM is applied to investigate the distribution of elements in single AgAu nanoparticles. The surface segregation of both Ag and Au, at different nanoparticle compositions, has been observed.

The use of energy dispersive X-ray tomography in the scanning transmission electron microscope to characterize elemental distributions within single nanoparticles in three dimensions is described.

能量色散X射线断层摄影术对个人纳米3D元素映射

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

对于新材料的低温磁输运测量先进的实验方法

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device. Test surfaces are chosen based on similarity to the screening environment, and the wipes can be made from any material considered for use in wipe-sampling. Particle samples of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) are applied in a fixed location on the surface using a dry-transfer technique. The particle samples, recently developed to simulate residues made after handling explosives, are produced by inkjet printing of RDX solutions onto polytetrafluoroethylene (PTFE) substrates. Collection efficiency is measured by extracting collected explosive from the wipe, and then related to critical sampling factors and the selection of wipe material and test surface. These measurements are meant to guide the development of sampling protocols at screening venues, where speed and throughput are primary considerations.

Optimized sampling protocols and the development of new wipe materials can be facilitated by standardized measurements of collection efficiency from wipe-sampling. Our approach for sampling trace explosives uses an automated device to control speed, force, and distance during wipe-sampling followed by extraction of collected explosives.

从微量炸药的擦拭取样测量收集效率的标准化方法

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

一种新的方法<em&gt;原位</em&gt;纳米级样品的机电表征

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

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

基于范德华 Heteroepitaxy 的柔性铁电元件制备及测量方法

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing challenge in the field is the fabrication of hybrid micro-nano structures using a facile, cost-effective, and high-throughput method. To overcome these challenges, this paper proposes a protocol to fabricate multiscale structures using only an imprint process with an anodic aluminum oxide (AAO) filter and an evaporative self-aggregation process of nanofibers. Unlike previous attempts that have aimed to straighten nanofibers, we demonstrate a unique fabrication method for multiscale aggregated nanofibers with high aspect ratios. Furthermore, the surface morphology and wettability of these structures on various liquids were investigated to facilitate their use in multifunctional surfaces.

Presented is an easy method to fabricate nano-micro multiscale structures, for functional surfaces, by aggregating nanofibers fabricated using an anodic aluminum oxide filter.

功能表面用印迹纳米纤维聚合的多尺度结构

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing ...

Studying Large Amplitude Oscillatory Shear Response of Soft Materials

We investigate the sequence of physical processes exhibited during large amplitude oscillatory shearing (LAOS) of polyethylene oxide (PEO) in dimethyl sulfoxide (DMSO) and xanthan gum in water &#8212; two concentrated polymer solutions used as viscosifiers in foods, enhanced oil recovery, and soil remediation. Understanding the nonlinear rheological behavior of soft materials is important in the design and controlled manufacturing of many consumer products. It is shown how the response to LAOS of these polymer solutions can be interpreted in terms of a clear transition from linear viscoelasticity to viscoplastic deformation and back again during a period. The LAOS results are analyzed via the fully quantitative Sequence of Physical Processes (SPP) technique, using free MATLAB-based software. A detailed protocol of performing a LAOS measurement with a commercial rheometer, analyzing nonlinear stress responses with the freeware, and interpreting physical processes under LAOS is presented. It is further shown that, within the SPP framework, a LAOS response contains information regarding the linear viscoelasticity, the transient flow curves, and the critical strain responsible for the onset of nonlinearity.

We present a detailed protocol outlining how to perform nonlinear oscillatory shear rheology on soft materials, and how to run the SPP-LAOS analysis to understand the responses as a sequence of physical processes.

软材料大振幅振荡剪切响应的研究

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