这项工作得到了美国国家科学基金会和先进的冷却技术批准号117041PO9621从批准号CBET-0651283。

1。制备纳米二氧化硅的沉积<ol><li>硅微粉干起，准备涂层样本，首先消除了大团聚。 </li><li>用乙醇二氧化硅微粒（直径为200纳米从凝胶Tec的公司购买）（190举证纯）洗净下通风柜与乙醇，直到所有的水分蒸发，留下样品。 </li><li>过筛颗粒通过一系列的金属网格（美国＃100-400）为了打破任何剩余的群。 </li><li>地方颗粒在管式反应器和一个小的磁力搅拌器栏， 如图1所示。颗粒应放在等离子区。 </li><li>放在两法兰，在玻璃管年底和连接到泵管O形圈密封的玻璃反应釜。 </li><li>安装法兰，并用手拧紧螺丝钳的周围围绕不锈钢夹环。 </li></ol> 2。真空系统的制备<ol><li>填充液氮陷阱，然后让表面的陷阱，成为冷。等待5分钟。 </li><li>在起泡添加异丙醇和连接到等离子体反应器。 </li><li>周围放置金属管橡胶O形圈密封起泡和起泡器连接螺母拧紧，直到管的地方变得密封。 </li></ol> 3。等离子体沉积过程<ol><li>放置在水浴温度为34±2°C的起泡</li><li>打开氩气流量控制器和输入设定点为6.00 SCCM。 </li><li>逐渐打开闸阀，玻璃管连接到泵泵工作时。认真执行这一步，因为压力突然下降，可能会导致颗粒流被风吹走。等到压力达到200毫托，然后离开闸阀全开。 </li><li>玻璃管置于磁力搅拌器，并设置速度为100 r下午。 </li><li>周围的管状玻璃反应器的无线电频率，射频发生器连接的铝圈和不锈钢钳连接到地面。 </li><li>匹配网络（埃尼MW-5D），然后切换的电源线和射频发生器电源的开启。设置在整个过程为30 W的功率。 </li><li>后关闭匹配网络的时间（10，20或40分钟），射频信号发生器，交流电源的具体时间。 </li><li>关闭单向阀，然后关闭氩气流量控制器。断开阀鼓泡和反应堆压力逐渐增加，大气。 </li><li>打开夹子，从管的粒子转移到塑料盘使用金属铲。 </li></ol> 4。解散芯材中空粒子的制备<ol><li>置于通风柜的整个过程中添加氢氟酸的样品。 </li><li>氢氟酸是一种极其合作rrosive酸和它的眼睛和皮肤的接触，可能会造成永久性的损害。使用护目镜，面罩和处理高频时穿实验室外套。 </li><li>氢氟酸（Aldrich公司占49％）10毫升与10毫升去离子水混合，并添加到包含包覆颗粒的塑料盘。 </li><li>塑料盘放在磁力搅拌器，并允许为核心，以24小时溶解。 </li><li>一天后，50毫升的去离子水稀释样品和样品离心1小时。丢弃在一个塑料容器在顶部的液体层和传输底层包含的粒子在塑料培养皿。 </li><li>加入50毫升去离子水和旋涡的样品，并再次离心。处置和转移的一个干净的培养皿中的颗粒层的顶层。 </li><li>的粒子用乙醇洗净，风干样品，并转移到一小瓶空心颗粒帽和保持颗粒在干燥器。 </li></ol> 5。甜心的的渗透cterization（核心发行利率） 材料：氯化钾为核心材料<ol><li> 0.001摩尔氯化钾（KCl）溶液混合0.0745克1升去离子水，氯化钾准备。 </li><li>恒定输出雾化器模型3076填充的玻璃瓶，安装瓶盖。 </li><li>连接压缩空气软管膜烘干机，雾化器连接到进气口。然后附加一个过滤器的出口软管，以收集氯化钾纳米粒子。 </li><li>逐渐打开压缩空气阀，并通过膜干燥器让空气流通。允许颗粒积聚在过滤器为5小时。 </li><li>关闭压缩空气阀，并小心地取出过滤器和收集的颗粒。置于干燥器中的粒子之前的涂层工艺。 </li><li>按照协议，2和3以获得氯化钾颗粒均匀涂布。 </li><li>混合涂层氯化钾10毫升去离子WA之三，在一个玻璃小瓶。为了充分混合样品，放入溶液磁力搅拌器，磁力搅拌器离开。在25°C孵育样品</li><li>电导率仪探头（热猎户座模型105）插入小瓶和记录超过30天的电导率。 </li></ol> 6。代表结果我们已经申请了这个过程的核心材料的品种，包括氧化物（二氧化硅），盐（氯化钾）和金属（铝）， 如图2所示。透射电子显微镜已被用来确认径向均匀薄膜，并测量其厚度。我们有成功包覆颗粒范围从37纳米到200纳米的直径（ 图2），但可以用这种方法处理的颗粒大小基本没有限制。壳沉积率大约为1海里/分钟。这相当缓慢的速度，使得它可以控制薄膜的厚度相当准确地通过沉积时间。等离子体聚合壳是一个渗透屏障，作为核心材料可以删除蚀刻或解散的事实证明。 图3显示了仍然硅芯被删除后的空壳。去除的核心是完整​​的和径向均匀性和薄膜的厚度相当高。通过这些薄膜的透气性评估的目的，我们交换为核心的材料氯化钾氯化钾解体以来，可以监视通过离子导电性的解决方案很容易。 图4显示了从核心的氯化钾4个样品的释放厚度不同，20纳米，40纳米，75纳米，95纳米，分别。涂层氯化钾颗粒悬浮在水中，溶液的电导率，为期30天。除了四个样品，未涂布氯化钾颗粒组成的控制也被监控。胶版纸解离氯化钾颗粒绿萼在很短的时间约1分钟。相比之下，氯化钾涂层显示了显着的释放速度较慢。包覆颗粒释放的特点是由最初爆发的第一个小时内的地方，其次要慢得多的版本，需要数天才能完成，取决于薄膜的厚度。 <img alt="图1" src="/files/ftp_upload/4113/4113fig1.jpg" /> 图1。制备纳米粒子，等离子体沉积和空心粒子形成的示意图表示。 <img alt="图2" src="/files/ftp_upload/4113/4113fig2.jpg" /> 图2。涂层的TEM照片（一），（二）与d的二氧化硅微粒= 200纳米（C），D = 37纳米的二氧化硅粒子，（四）与d〜100 nm的铝，及（e）氯化钾颗粒D = 100 nm的<img alt="图3" src="/files/ftp_upload/4113/4113fig3.jpg" /> 图3，TEM后蚀刻（一），（b）与硅芯直径为200 nm，（三）氯化钾的核心空心颗粒的图像。 <img alt="图4" src="/files/ftp_upload/4113/4113fig4.jpg" /> 图4。释放壳厚度的影响。插图图显示了在第一个小时释放。

<ol>
	<li>Xu, X., Asher, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Utilization+of+Monodisperse+Hollow+Polymeric+Particles+in+Photonic+Crystals.">Synthesis and Utilization of Monodisperse Hollow Polymeric Particles in Photonic Crystals.</a> Journal of the American Chemical Society. 126, 7940-7945 (2004).</li><li>Lou, X., Archer, L., Yang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hollow+Micro-/nanostructures:+Synthesis+and+Applications.">Hollow Micro-/nanostructures: Synthesis and Applications.</a> Advanced Material. 20, (2008).</li><li>Kim, D. J., Kang, J. Y., Kim, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coating+of+TiO2+Thin+Films+on+Particles+by+a+Plasma+Chemical+Vapor+Deposition+Process.">Coating of TiO2 Thin Films on Particles by a Plasma Chemical Vapor Deposition Process.</a> Advanced Powder Technology. 21, 136-140 (2010).</li><li>Marino, E., Huijser, T., Creyghton, Y., van der Heijden, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Coating+of+Copper+Oxide+Nanoparticles+Using+Atmospheric+Pressure+Plasmas.">Synthesis and Coating of Copper Oxide Nanoparticles Using Atmospheric Pressure Plasmas.</a> Surface and Coatings Technology. 201, 9205-9208 (2007).</li><li>Hakim, L., King, D., Zhou, Y., Gump, C., George, S., Weimer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticle+Coating+for+Advanced+Optical,+Mechanical+and+Rheological+Properties.">Nanoparticle Coating for Advanced Optical, Mechanical and Rheological Properties.</a> Advanced Functional Materials. 17, 3175-3181 (2007).</li><li>Kim, S. H., Kim, J., Kang, B., Uhm, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superhydrophobic+CFx+Coating+via+In-Line+Atmospheric+RF+Plasma+of+He-CF4-H2.">Superhydrophobic CFx Coating via In-Line Atmospheric RF Plasma of He-CF4-H2.</a> Langmuir. 21, 12213-12217 (2005).</li></ol>

没有利益冲突的声明。

纳米涂层的最大挑战之一是提供一个兼容的化学涂层与基体1,2之间。这里描述的方法的优点是，它不是特定材料。等离子聚合物表明对各种基材，包括硬质金属（ 图2（c）条 ），硅胶（ 图2（c）），硅或软质材料（如聚合物）优异的附着力，而不需要任何特殊的表面改性3 4,5。该技术具有更大的优势，它不是由核心颗粒大小的限制，并在纳米和微米范围?...

<table border="1"><tbody><tr><td>二氧化硅微粒</td><td> geltech公司</td><td></td><td></td></tr><tr><td>氯化钾（晶体） </td><td>电解二氧化锰化学品公司</td><td></td><td></td></tr><tr><td>异丙醇（99.9％） </td><td> Sigma-Aldrich公司</td><td></td><td></td></tr><tr><td>氢氟酸（48-51％） </td><td>厂商VWR </td><td></td><td></td></tr><tr><td>管道和法兰</td><td>世伟洛克</td><td></td><td> ¼直径1英寸</td></tr><tr><td>粗加工泵</td><td>爱德华兹</td><td></td><td></td></tr><tr><td>液氮陷阱</td><td>及ñ公司的</td><td></td><td></td></tr></tbody></table>

encapsulation and permeability characteristics of plasma polymerized hollow particles

在这个协议中，核壳纳米结构的等离子体增强化学气相沉积合成。我们生产各种固体物质，包括二氧化硅和氯化钾异丙醇等离子体聚合非晶屏障。这种多用途的技术被用来治疗范围从37纳米到1微米大小的纳米粒子和纳米粉体，沉积的薄膜，其厚度可以在任何地方从1纳米到100纳米以上。解散的核心，让我们学习的渗透通过薄膜的速率。在这些实验中，我们确定氯化钾通过阻隔膜的扩散系数涂层氯化钾纳米随后监测包覆颗粒悬浮在水中的离子电导率。在这个过程中的主要兴趣是溶质的封装和缓释。壳的厚度是由我们控制释放速率的独立变量之一。它具有强效率释放，从而增加了六个小时的释放（壳厚度为20 nm）到30天以上的长期释放（壳厚度为95纳米）。释放曲线显示了特有的行为：在前五分钟开始解散后，慢释放所有的核心材料，才最终材料（35％）快速释放出来。

Watch this Scientific Journal Video about Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles at JoVE.com

Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

我们已经用等离子体增强化学气相沉积存入范围从几纳米到几100对各种材料的纳米粒子的纳米薄膜。我们随后蚀刻的核心原料生产空心球壳，其渗透壳的厚度控制。我们描述了这些涂料的透气性小分子，并证明这些障碍可以提供数天的核心材料的缓释。

等离子体聚合空心颗粒的封装和渗透特征

In this protocol, core-shell nanostructures are synthesized by plasma enhanced chemical vapor deposition. We produce an amorphous barrier by plasma ...

encapsulation-permeability-characteristics-plasma-polymerized-hollow

Research

Education

JoVE Core

JoVE Journal

Civil Engineering

Engineering

Unit 1

Permeability of Concrete

SCIENTISTS IN ACTION

10.6K 次观看.  The Pennsylvania State University. 我们已经用等离子体增强化学气相沉积存入范围从几纳米到几100对各种材料的纳米粒子的纳米薄膜。我们随后蚀刻的核心原料生产空心球壳，其渗透壳的厚度控制。我们描述了这些涂料的透气性小分子，并证明这些障碍可以提供数天的核心材料的缓释。

视频: Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a significant role in laser-material interaction, especially in the air environment1-11.
Early plasma evolution has been captured through pump-probe shadowgraphy1-3 and interferometry1,4-7. However, the studied time frames and applied laser parameter ranges are limited. For example, direct examinations of plasma front locations and electron number densities within a delay time of 100 picosecond (ps) with respect to the laser pulse peak are still very few, especially for the ultrashort pulse of a duration around 100 femtosecond (fs) and a low power density around 1014 W/cm2. Early plasma generated under these conditions has only been captured recently with high temporal and spatial resolutions12. The detailed setup strategy and procedures of this high precision measurement will be illustrated in this paper. The rationale of the measurement is optical pump-probe shadowgraphy: one ultrashort laser pulse is split to a pump pulse and a probe pulse, while the delay time between them can be adjusted by changing their beam path lengths. The pump pulse ablates the target and generates the early plasma, and the probe pulse propagates through the plasma region and detects the non-uniformity of electron number density. In addition, animations are generated using the calculated results from the simulation model of Ref. 12 to illustrate the plasma formation and evolution with a very high resolution (0.04 ~ 1 ps).
Both the experimental method and the simulation method can be applied to a broad range of time frames and laser parameters. These methods can be used to examine the early plasma generated not only from metals, but also from semiconductors and insulators.

An experimental method to examine the early plasma evolution induced by ultrashort laser pulses is described. Using this method, high quality images of early plasma are obtained with high temporal and spatial resolutions. A novel integrated atomistic model is used to simulate and explain the mechanisms of early plasma.

超短激光脉冲诱导的等离子体演化早期的调查

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a ...

科研

工程学

Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids

An experimental study is performed to measure the terminal settling velocities of spherical particles in surfactant based shear thinning viscoelastic (VES) fluids. The measurements are made for particles settling in unbounded fluids&#160;and fluids between parallel walls. VES fluids over a wide range of rheological properties are prepared and rheologically characterized. The rheological characterization involves steady shear-viscosity and dynamic oscillatory-shear measurements to quantify the viscous and elastic properties respectively. The settling velocities under unbounded conditions are measured in beakers having diameters at least 25x the diameter of particles. For measuring settling velocities between parallel walls, two experimental cells with different wall spacing are constructed. Spherical particles of varying sizes are gently dropped in the fluids and allowed to settle. The process is recorded with a high resolution video camera and the trajectory of the particle is recorded using image analysis software. Terminal settling velocities are calculated from the data.
The impact of elasticity on settling velocity in unbounded fluids is quantified by comparing the experimental settling velocity to the settling velocity calculated by the inelastic drag predictions of Renaud et al.1&#160;Results show that elasticity of fluids can increase or decrease the settling velocity. The magnitude of reduction/increase is a function of the rheological properties of the fluids and properties of particles. Confining walls are observed to cause a retardation effect on settling and the retardation is measured in terms of wall factors.

This paper demonstrates the experimental procedure to measure terminal settling velocities of spherical particles in surfactant-based shear thinning viscoelastic fluids. Fluids over a wide range of rheological properties are prepared and settling velocities are measured for a range of particle sizes in unbounded fluids and fluids between parallel walls.

无约束和封闭表面活性剂中球形粒子沉降速度的实验测量 剪切变薄粘性流体

An experimental study is performed to measure the terminal settling velocities of spherical particles in surfactant based shear thinning viscoelastic ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators &#8212; a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes.

This movie shows how an atmospheric plasma torch can be ignited by microwaves with no additional igniters and provides a stable and continuous plasma operation suitable for plenty of applications.

如何点燃常压微波等离子体炬没有任何额外的点火器

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

测量的方向和旋转速率方法3D打印在湍流颗粒

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...

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 ...

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line intensity ratios. By using a Johann spectrometer viewing the plasma, it is possible to construct profiles of plasma parameters such as density, temperature, and velocity with good spatial and time resolution. However, benchmarking atomic code modeling of X-ray spectra obtained from well-diagnosed laboratory plasmas is important to justify use of such spectra to determine plasma parameters when other independent diagnostics are not available. This manuscript presents the operation of the High Resolution X-ray Crystal Imaging Spectrometer with Spatial Resolution (HIREXSR), a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma. In addition, this manuscript covers a laser blow-off system that can introduce such ions to the plasma with precise timing to allow for perturbative studies of transport in the plasma.

X-ray spectra provide a wealth of information on high temperature plasmas. This manuscript presents the operation of a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma.

运用X射线成像光谱水晶的使用为高温等离子体诊断

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line ...

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling immensely. However, in soft electronics, in which organic semiconductors play a critical role, the devices will be bent or folded repeatedly. The effect of bending on the crystal packing and thus the charge transport is crucial to the performance of the device. In this manuscript, we describe the protocol to bend a single crystal of 5,7,12,16-tetrachloro-6,13-diazapentacene (TCDAP) in the field-effect transistor configuration and to obtain reproducible I-V characteristics upon bending the crystal. The results show that bending a field-effect transistor prepared on a flexible substrate results in nearly reversible yet opposite trends in charge mobility, depending on the bending direction. The mobility increases when the device is bent toward the top gate/dielectric layer (upward, compressive state) and decreases when bent toward the crystal/substrate side (downward, tensile state). The effect of bending curvature was also observed, with greater mobility change resulting from higher bending curvature. It is suggested that the intermolecular &#960;-&#960; distance changes upon bending, thereby influencing the electronic coupling and the subsequent carrier transport ability.

This manuscript describes the bending process of an organic single crystal-based field-effect transistor to maintain a functioning device for electronic property measurement. The results suggest that bending causes changes in the molecular spacing in the crystal and thus in the charge hopping rate, which is important in flexible electronics.

弯曲对基于晶体的柔性有机单场效应晶体管的电气特性的影响

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling ...

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. The reactions of cold plasma with the surrounding atmosphere yield a variety of reactive species, which can define its effectiveness. While efficient development of cold plasma therapy requires kinetic models, model benchmarking needs empirical data. Experimental studies of the source of reactive species detected in aqueous solutions exposed to plasma are still scarce. Biomedical plasma is often operated with He or Ar feed gas, and a specific interest lies in investigation of the reactive species generated by plasma with various gas admixtures (O2, N2, air, H2O vapor, etc.) Such investigations are very complex due to difficulties in controlling the ambient atmosphere in contact with the plasma effluent. In this work, we addressed common issues of &#39;high&#39; voltage kHz frequency driven plasma jet experimental studies. A reactor was developed allowing the exclusion of ambient atmosphere from the plasma-liquid system. The system thus comprised the feed gas with admixtures and the components of the liquid sample. This controlled atmosphere allowed the investigation of the source of the reactive oxygen species induced in aqueous solutions by He-water vapor plasma. The use of isotopically labelled water allowed distinguishing between the species originating in the gas phase and those formed in the liquid. The plasma equipment was contained inside a Faraday cage to eliminate possible influence of any external field. The setup is versatile and can aid in further understanding the cold plasma-liquid interactions chemistry.

An experimental setup was created for the helium-operated kHz frequency plasma jet. The setup includes a cage for the plasma power supply and jet and an in-house built reactor to monitor plasma-induced reactive species without the interference of the ambient atmosphere.

大气压等离子体设置调查活性物种形成

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. ...

Spark Plasma Sintering Apparatus Used for the Formation of Strontium Titanate Bicrystals

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with one twist grain boundary. This apparatus utilizes high uniaxial pressure and a pulsed direct current for rapid consolidation of material. Diffusion bonding of strontium titanate bicrystals without fracture, in a spark plasma sintering apparatus, is possible at high pressures due to the unusual temperature dependent plasticity behavior of strontium titanate. We demonstrate a method for the successful formation of bicrystals at accelerated time scales and lower temperatures in a spark plasma sintering apparatus compared to bicrystals formed by conventional diffusion bonding parameters. Bond quality was verified by scanning electron microscopy. A clean and atomically abrupt interface containing no secondary phases was observed using transmission electron microscopy techniques. Local changes in bonding across the boundary was characterized by simultaneous scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy.

A viable technique for the formation of strontium titanate bicrystals at high pressure and fast heating rate via the spark plasma sintering apparatus is developed.

放电等离子烧结设备中使用的钛酸锶双晶体的形成

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with ...

Optimization, Test and Diagnostics of Miniaturized Hall Thrusters

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without attendance and adjustment. Thermochemical thrusters which utilize thermodynamic properties of gases as a means of acceleration have physical limitations on their exhaust gas velocity, resulting in low efficiency. Moreover, these engines demonstrate extremely low efficiency at small thrusts and may be unsuitable for continuously operating systems which provide real-time adaptive control of the spacecraft orientation, velocity and position. In contrast, electric propulsion systems which use electromagnetic fields to accelerate ionized gases (i.e., plasmas) do not have any physical limitation in terms of exhaust velocity, allowing virtually any mass efficiency and specific impulse. Low-thrust Hall thrusters have a lifetime of several thousand hours. Their discharge voltage ranges between 100 and 300 V, operating at a nominal power of &lt;1 kW. They vary from 20 to 100 mm in size. Large Hall thrusters can provide fractions of millinewton of thrust. Over the past few decades, there has been an increasing interest in small mass, low power, and high efficiency propulsion systems to drive satellites of 50-200 kg. In this work, we will demonstrate how to build, test, and optimize a small (30 mm) Hall thruster capable of propelling a small satellite weighing about 50 kg. We will show the thruster operating in a large space environment simulator, and describe how thrust is measured and electric parameters, including plasma characteristics, are collected and processed to assess key thruster parameters. We will also demonstrate how the thruster is optimized to make it one of the most efficient small thrusters ever built. We will also address challenges and opportunities presented by new thruster materials.

Here, we present a protocol to test and optimize space propulsion systems based on miniaturized Hall-type thrusters.

小型化霍尔推进器的优化、测试和诊断

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without ...