作者感谢沃尔克·罗威尔（基尔大学实验和应用物理研究所）对设备的帮助。这项工作得到了CRC 1316 瞬态大气等离子体内的DFG的支持，在 冷大气等离子体项目中，为研究与生物基板的基本相互作用机制 （项目ID BE 4349/5-1），以及在 伤口愈合中由等离子体生成的一氧化氮 项目（项目ID SCHU 2353/9-1）。

1. 供气供应和控制大气
<ol><li>设置由全金属气体管组成的气体供应，避免任何TPFE或类似的塑料管24。保持天然气供应线尽可能短，以避免任何杂质，并促进泵送供气系统。</li>
	<li>根据 COST-Jet 的典型气体流量速率选择用于提供进气的质量流量控制器。使用纯度至少为 99.999% 的工作气体。 注:成本喷气机的主要工作气体是氦气。操作可以以 100 sccm 到大约 5000 sccm 的流速率实现，其中 1000 sccm 是最常见的值。</li>
	<li>通过由多个质量流量控制器组成的系统实现活性气体的混合。对于较小的混音，使用反混合单元，以减少混合完成25所需的时间。 注:常见的混合物是氧气和氮气，流速在 5 sccm（工作气体的 0.5%） 左右。</li>
	<li>在气体供应线和喷气管之间添加一个阀门，以防止潮湿的空气进入气体供应时，设备不使用，因为水是最常见的和最有问题的杂质在大气压力等离子体，严重影响等离子体化学。</li>
	<li>在表面处理前清洁气体供应线，以减少管中的杂质。为此，要么简单地设置约1000sccm氦气的中等气流，冲洗供应线，或者，最好是反复泵送和补充供应线（约三次）。 注意:只需冲洗供气管线，可能需要数小时才能清洁系统，具体取决于污染状况。</li>
	<li>在气体供应管线中加入分子筛陷阱或冷陷阱（例如使用液氮），以进一步降低进一步降低进一步降低进气的湿度。</li>
	<li>相反，如果作为试剂需要控制水量，则向系统26、27添加气泡器。</li>
	<li>考虑为您的实验设置一个受控大气，因为环境大气成分的变化可能会影响等离子体废水中的化学反应。 注:这种效果对于COST-Jet28来说可能不太明显，因为电场配置将等离子体限制在放电通道内部，但对于活动等离子体部分在设备外部的其他CAP设备来说，可能扮演重要角色。</li>
</ol>2. 设备的组装和设置
<ol><li>将成本喷射设备连接到气体供应。将设备直接连接到 1/4 英寸不锈钢斯瓦格洛克管。使用适配器达到不同的管标准。</li>
	<li>使用配备 SMC 连接器的屏蔽 BNC 电缆将成本喷气机连接到电源。</li>
	<li>将集成的电气探头连接到示波器，以使用 50 Ohm 电阻作为终止来监控电压和电流。</li>
	<li>打开 COST-Jet 外壳，将适当补偿的商业电压探头连接到供电的铜线以及喷气机的接地部分（例如，斯瓦格洛克气管）和示波器。</li>
	<li>执行探头校准程序:将小电压施加到 COST-Jet 上，然后使用螺丝刀调整 LC 电路的可变电容器，以达到最佳耦合（最大测量电压）。使用线性回归将实际电压（商业探头）与测量的电压（已实施探头）进行比较，并计算校准常数，从而进行电压校准。拆下商业电压探头并关闭成本喷射外壳。</li>
	<li>再次，对 COST-Jet 施加小电压，然后使用螺丝刀调整 LC 电路的可变电容器，以达到最佳耦合。</li>
	<li>在 COST-Jet 设备中点火等离子体:首先，使用质量流量控制器 （MFC） 设置大约 1slpm 氦气流速。打开气体供应系统和成本喷射最后之间的阀门。然后，在电极上施加低电压，增加振幅，直到等离子体点火。</li>
	<li>如果第一次点火时，电极不干净并妨碍点火，则应用较高的初始电压，并在点火后迅速降低电极。或者，使用火花枪，以方便更容易的第一次点火。</li>
	<li>将操作控制参数（气体流量、施加电压）设置为所需的值。</li>
	<li>给设置一点热身时间，使热稳定（约20分钟），以确保稳定和可重复的操作条件。</li>
	<li>要在实验中改变气体成分，请根据气体供应设置提供大约 2 分钟的平衡时间。 注:成本喷气机现已准备就绪，可以申请。</li>
</ol>3. 功率测量
<ol><li>将监控 COST-Jet 的电压和电流的示波器连接到计算机。</li>
	<li>将"COST电源监视器"软件安装到计算机29上，允许实时电源监控11，19。</li>
	<li>通过执行控制特定示波器所需的命令来调整软件和示波器之间的通信。</li>
	<li>启动成本功率监视器软件并切换到 "设置" 面板。填写连接到示波器的正确通道，以及第 2.4 步确定的校准常数。 注:如果商业电压探头连接到 COST-Jet， 则 Find 按钮可用于自动计算校准因子。</li>
	<li>更改为 扫描 面板。按下 Find 按钮，在等离子体仍然关闭时，采取参考阶段。在此测量之前关闭气体流量，并施加一个电压，该电压在用于实际操作放电的典型电压范围内，因为与惰性气体主导的气体混合物相比，等离子体不会在空气中点火。使用此测量自动校正电压和电流探头之间的相对相位移，假设此处的完美电容器的 90° 相。</li>
	<li>按 下"开始 "和 "暂停 "按钮以启动或暂停电气测量。</li>
	<li>根据需要操作成本喷气机。使用从电压和电流振幅以及相移计算的实际功率，这些电能会持续显示在软件中以进行监控并作为控制参数。</li>
</ol>4. （固体）表面处理
<ol><li>为您的实验设置一个受控的氛围。 注:就COST-Jet而言，受控大气不如密闭放电通道外具有活性等离子化学的源重要。</li>
	<li>按照第 1.5 步所述清洁天然气供应管道。</li>
	<li>设置所需的操作参数，等待约 20 分钟，直到 COST 喷气机达到稳定的温度。</li>
	<li>选择COST-Jet和处理表面之间的距离，因为距离决定了在处理表面30上影响反应物种的数量。使用 xyz 阶段安装基板，以便轻松操作。 注:对于 COST-Jet，安全间隙为等离子体放电和处理表面之间的距离增加了一毫米。</li>
	<li>开始治疗时间:要么简单地打开等离子体，要么使用机械快门。请注意在切换事件期间可能发生的电压过冲导致放电受限制。要更好地控制 ms 范围，请使用可旋转快门。</li>
	<li>以所需的时间处理样品，并通过关闭血浆或使用快门结束治疗时间。</li>
	<li>如有必要，使用Schlieren成像技术检查目标前方的气体流动模式，当将基板视为表面充电、离子阻力或浮力导致的环境空气混合的影响时，可能会影响到达表面的活性物种的数量。</li>
</ol>5. 液体处理
<ol><li>为实验设置一个受控的氛围。</li>
	<li>按照第 1.5 步所述清洁天然气供应管道。</li>
	<li>设置所需的操作参数，等待大约 20 分钟，成本喷气机才能达到稳定的温度。</li>
	<li>选择成本喷气机和处理过的液体之间的距离。</li>
	<li>将液体倒入适当的容器中处理。使用惰性材料，避免液体中可能产生的活性物种与容器发生反应。根据处理的液体量选择容器的大小。</li>
	<li>考虑气体流对液体表面的影响:根据气体流速，注意可能形成的凹陷半月板，从而改变等离子体和液体表面之间的距离。</li>
	<li>开始治疗。避免气体流动突然变化导致液体表面的压力激增，因为这可能导致液体溅入放电几何体，可能导致短路，并肯定污染等离子体。相反，使用机械快门或缓慢增加气体流量。</li>
	<li>考虑到中性气体流和液体表面之间的摩擦导致液体的混合/搅拌，因为这会影响液体中的运输过程和浓度配置文件。此外，根据治疗时间，正确处理治疗期间液体蒸发（例如计算反应常数时）。根据等离子体来源，请注意这种蒸发可能导致与放电的背耦合，从而改变等离子体化学。</li>
	<li>还请考虑液体中可能的试剂的反应性也受到此剂表面活性的影响。因此，在某些情况下，表面活性剂可能在短命物种和液体之间的相互作用中发挥重要作用。</li>
</ol>

作者没有什么可透露的。

在这里，我们演示了使用大气压力等离子喷射对不同材料进行表面处理。大气压力等离子喷射的实验设置对等离子体参数、化学成分和性能具有巨大影响，从而影响等离子体处理的结果，是协议中的关键一步。
例如，气体供应线对等离子体中最常见的杂质（即湿度）起着重要作用。特别是，由于与水分子和氮35相比，氧气的电电能量较低，因此在等离子体中活性氮种的产量减少，而活性氧品种的产量则受到青睐。冬季24 发现，由于孔隙度和储存能力较高，使用聚合物管的源自内管表面水分子的进气湿度比金属管高一个数量级。可以通过用进气冲洗管道来减少。但是，通过冲洗干燥线路需要几个小时。因此，应避免或至少保持尽可能短的聚合物管。这些发现在格罗-克雷尔25号的研究中得到了强调。他们利用质谱法比较了聚酰胺和不锈钢管对等离子体化学的影响。他们的测量结果证实，由于聚合物管的喷水以及金属管干燥时间的加快，等离子体中的水团离子形成。此外，他们还研究了气体净化方法（如分子筛陷阱和液氮冷陷阱）对等离子体化学的影响，这些方法有助于将杂质量减少约两个数量级。
与其试图净化饲料气体，不如增加控制湿度的方法。由于这种故意杂质随后主导了自然杂质，从而控制了等离子体化学，因此只要准确知道增加的湿度量，就可重复的条件得到保证。
对于放电点火，电极施加的电压通常可以简单地增加，直到故障点。但是，根据电极的表面条件，有时需要高压。为了方便点火，可以使用高压火花枪。当尝试在 COST-Jet 中点燃气孔放电时，这也可能很有用。
在将 COST-Jet 应用于任何表面之前，应分配足够的时间让设备平衡。当设置为所需的控制参数时，COST-Jet 需要大约 20 分钟才能达到稳定的条件 11。在此期间，设备温度、气体温度以及等离子体化学都达到了稳定状态。
为了比较科学结果，需要具有可比的等离子体控制参数。用于测量电力输入功率，COST 电源监视器可用于29。该软件是开源的，与一系列不同类型的示波器兼容。该软件按照戈尔达19号描述的原则运行。
除了饲料气体湿度对等离子体化学的影响外，活性物种从等离子体输送到基板在污水成分中起着重要作用，是协议中的另一个关键步骤。周围的大气会影响在等离子体中形成的物种，这些物种会在前往基底的路上产生。为了尽量减少这种影响，使用了两个不同的概念:（i） 首先，可以建立一个由进气组成的受控大气。因此，周围大气的组成可以保持恒定。根据处理所需的纯度水平，可通过配备单向阀的保护性外壳实现受控大气，以防止过压。对于更高的纯度水平，可以使用带泵的真空室。（二） 第二，利用等离子体污水36、37周围的屏蔽气体幕布，可以形成受控大气。通常，它由惰性气体组成，但也可以根据应用程序的需要进行变化。
幸运的是，对于COST-Jet来说，周围大气的影响是相当低的。戈尔巴涅夫利用同位素标记表明，对于平行场配置等离子喷射，到达液态表面的活性氧和氮种是在等离子体气体相以及等离子喷嘴和样品38、39之间的区域形成的。相比之下，他们使用同样的技术为COST-Jet，他们发现RONS几乎完全来自等离子相，而不是周围的环境28。这可能是由于电场被限制在COST-Jet放电的等离子通道。这使得等离子体放电在很大程度上独立于其环境，并赋予它某种远程特性。
对于纵向电场等离子喷射，Darny等人已经 表明，电场的极性改变了气流模式，从而也改变了因离子风而达到目标的活性物种。斯坦坎皮亚诺等人的测量证实了活性物种密度对环境的依赖性。他们根据电特性报告了在处理水中产生的活性物种数量的差异。为了弥补这些差异，他们不得不创建一个补偿电路。此行为对于 COST-Jet 来说是不同的: 图 5 比较了没有施加电压的 COST-Jet 的施利伦图像，以及在操作过程中的两种不同的气体流量速率。这些图像是使用凯利41描述的单镜内联对齐拍摄的。它们显示了水平对齐的 COST-Jet 废水如何击中平板玻璃基板。这两幅图像都显示了完全相同的气体流动模式。这是由于等离子体废水中缺少带电的物种而缺乏离子风造成的。
此外，COST-Jet 还展示了非常层层流动模式。Kelly41 展示了与 图 5中显示的类似施利伦图像，用于各种气体流量。即使在2点的相当高的气体流量下，等离子体流出液也没有湍流的迹象。在0.25 slpm及以下的极低气体流量下，氦气的浮力开始发挥作用。然而，距离喷嘴高达4至5毫米的距离，环境大气不会影响气体成分到达表面，如Ellerweg使用质谱仪17所证明的那样。
上述所有特征都增加了成本喷气机的远程特性。这使得它成为控制，可比的表面处理的理想人选。
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/61801/61801fig05.jpg"> 图5:施利伦图像的成本喷气机有和没有应用电压为两种不同的气体流量。在等离子体操作中，气体流模式与只有气体流的模式完全相似。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/61801/61801fig05large.jpg" target="_blank">请单击此处查看此图的较大版本。</a>
根据对处理样品的预期效果，可以相应地调整气体流动混合物、应用电力以及等离子体源与表面之间的距离。对于COST-Jet来说，存在一个广泛的文献数据库，用于研究污水中的活性物种。例如，威廉斯30 号利用质谱法测量了原子氧密度，而施耐德42 号测量了污水中的原子氮密度。
使用大气压力等离子体处理液体可导致由反应物种、离子、光子或电场驱动的各种可能反应机制。由于 COST-Jet 先前描述的特征，与等离子体与液体直接接触的等离子源相比，电场、离子和光子的影响可以忽略不计的。因此，为了研究短命反应物种，如原子氧对酚溶液的影响，成本喷气机被赫夫尼43 和贝内迪克特44使用。此外，COST-Jet提供了一个方便的可能性，比较实验和液体处理的数字模拟28。由于等离子体和液体之间的相互作用主要受从等离子体到液体表面的活性物种的气体流动的影响，模型的复杂性可以降低。
液体的气流诱导搅拌会增加等离子体产生的活性物种和液体之间的反应速率。与固体的表面处理相比，液体的对流不断改变反应物的局部浓度。此外，血浆生成的物种与液体中反应物之间的反应率也受到这些反应物表面活动的影响。随着表面活性增加，反应剂在液体表面的浓度增加。这些表面活性剂可能在等离子体产生的短寿命物种的反应中发挥重要作用。
除了搅拌影响液体表面的气体流，还会诱发蒸发，必须考虑。使用治疗时间短的 COST-Jet，蒸发可能起次要作用，尽管计算正确的反应速率仍需考虑。COST-Jet 的放电不受蒸发的影响，因此等离子体化学也不会受到影响。对于不同的等离子体来源，例如等离子体与液体直接接触，等离子体化学成分随着蒸发而发生显著变化，如田和库什纳45所示，用于介电屏障放电。此外，对于金笔，蒸发的影响被确定为46。
除了这些提到的等离子体化学差异，需要考虑不同的等离子体来源，也是由气流引起的半月板在液体表面变化的拓扑。这种半月板的深度通常取决于气体速度。对于等离子体源，其中电极配置诱导一个重要的电场到达液体，甚至与等离子体接触液体，这种半月板可以升高47，48。如前所示，需要根据使用的等离子体源考虑若干影响。
将来，此协议可用于使用 COST-Jet 进行表面和液体处理。它是一种稳定、可重复的等离子源，在众多不同的等离子喷射设计中表现出独特的远程特性。同样的方法不仅限于COST-Jet源，可以修改和调整，以与任何冷大气压力等离子源一起使用。

近年来，冷大气压力等离子体（CAPs）因其表面处理应用的潜力而越来越受到关注。CAP 的特点是其非均衡特性，使复杂的等离子体化学与高密度的活性物种，同时保持对处理过的样品的低热冲击。因此，CAP特别考虑用于生物组织1，2，3，4的治疗。CAP 的许多概念和设计被成功用于伤口消毒和愈合、血液凝固和癌症治疗等生物医学应用。很大一部分生物组织含有液体。因此，研究也越来越侧重于研究CAP对液体表面的影响，如细胞介质或水5，6，7。
然而，科学结果往往遭受可靠性和可重复性问题8，9，10。一方面，经过处理的生物基材受自然变异的影响。另一方面，生物机制很少直接归因于等离子体过程（如电场、紫外线辐射以及长寿命和短寿命物种等）。此外，这些等离子体过程反过来又严重依赖于单个等离子体源及其应用的确切类型。
此外，很少提供详细的治疗程序协议。这使得很难隔离特定血浆参数对治疗结果的影响，从而使获得的结果无法转移。
因此，最近已经尝试用冷大气压力等离子体来标准化表面、组织和液体的处理。在这里，我们只介绍一些选定的例子。
<ol><li>为了简化不同等离子源的直接比较，开发了参考源。受低压等离子体社区的启发，在COST行动MP 1101的框架下开发了可重复和稳定的放电设计（COST-Jet），可作为未来生物医学研究的参考来源。</li>
	<li>为了实现可比性，制定了针对单个应用程序的参考协议。例如，为了标准化冷大气压力等离子体抗菌特性的比较，Mann等人通过规范每个区域单位12的处理时间，确定了微生物治疗的参考协议。</li>
	<li>为了更灵活的方法，科格尔海德等人开发了一种方法，用于研究大分子13的血浆引起的化学修饰。他们利用微量化合物，如赛尔泰因和或含赛因谷胱甘肽（GSH），结合FTIR和质谱法，试图推断生物基板上的化学修饰。使用这种方法，已经比较了几个等离子体来源，如COST-Jet、kinPen和CinogyDBD。</li>
	<li>要直接比较单个等离子体源，必须建立可比的控制参数。基本等离子体参数，如电子温度、电子密度和活性物种的通量密度，在大气压力等离子体中很难测量，因为这种等离子体往往是瞬态的，其尺寸很小。相反，外部控制参数，如发电机功率，施加电压或点火，和电弧点经常用作参考，尤其是当比较结果与模拟17，18。最近，测量的电力能耗被用作更可靠的控制参数19，20，21。</li>
</ol>尽管做出了这些努力，但仅仅由于在表面正确应用等离子体源的挑战，比较不同研究的结果可能仍然是不可能的。在处理大气压力等离子体应用时，需要解决大量普遍存在的陷阱，例如外部电场（补偿电路）、等离子体与周围环境之间的反馈回路（屏蔽大气）、物种传输（离子风）和控制参数（电压、电流、功率）。
这项工作的主要目标是提供一个彻底的，详细的协议，应用COST-Jet表面处理。COST-Jet 是一种可靠的等离子体源，用于科学参考目的，而不是工业或医疗用途。它提供了可重复的放电条件和广泛的数据库，可用的研究22，23。COST-Jet 基于同质的电容耦合射频等离子体。由于电场与气体流动垂直，带电物种大多保存在排放区域，不与目标或周围大气相互作用。此外，层压气体流可确保等离子体流中的可重复等离子体化学条件。
在本文中，我们将解决最常见的挑战，并引入文献中使用的可能解决方案。其中包括适当的气体供应、放电控制、环境大气影响和表面准备。遵守此处提出的协议应确保测量的可重复性和可比性。
该协议也可以作为其他大气压力源的一个例子。它必须根据单独的气流和电场配置，对其他喷气等离子体来源进行精炼。在适用的情况下，我们将尝试指出对协议的可能调整。在发表将大气压力等离子体应用于处理样品的研究时，应考虑并报告上述步骤。

<table><tbody><tr><td>COST power monitor software</td><td>home-built</td><td></td><td>according to www.cost-jet.eu and J Golda et al 2016 J. Phys. D: Appl. Phys. 49 084003</td></tr><tr><td>COST-Jet (including matching circuit)</td><td>home-built</td><td></td><td>according to www.cost-jet.eu and J Golda et al 2016 J. Phys. D: Appl. Phys. 49 084003</td></tr><tr><td>current probe</td><td>home-built</td><td></td><td>integrated into the COST-Jet</td></tr><tr><td>gas supply system</td><td>Swagelok</td><td></td><td>stainless steel</td></tr><tr><td>helium</td><td>Air Liquide</td><td></td><td>99.999 % purity</td></tr><tr><td>mass flow controller (MFC)</td><td>Analyt-MTC</td><td>series 358</td><td>5000 sccm</td></tr><tr><td>MFC</td><td>Analyt-MTC</td><td></td><td>50 sccm</td></tr><tr><td>oscilloscope</td><td>Agilent Technologies</td><td>DSO7104B</td><td>bandwidth 1 GHz, resolution 4 Gsa/s</td></tr><tr><td>oxygen</td><td>Air Liquide</td><td></td><td>99.9999 % purity</td></tr><tr><td>power supply</td><td>home-built</td><td></td><td>according to www.cost-jet.eu and J Golda et al 2016 J. Phys. D: Appl. Phys. 49 084003</td></tr><tr><td>voltage probe</td><td>Tektronix</td><td>P5100A</td><td></td></tr><tr><td>xyz-stage</td><td>Zaber</td><td>ZAB-X-XAZ-LSM0100A-K0059-SQ3</td><td></td></tr></tbody></table>

treating surfaces with a cold atmospheric pressure plasma using the cost-jet

近年来，非热大气压力等离子体被广泛用于表面处理，特别是由于其在生物应用方面的潜力。然而，由于血浆条件不可靠以及复杂的治疗程序，科学结果往往存在可重复性问题。为了解决这一问题，并提供稳定和可重复的等离子体源，开发了COST-Jet参考源。
在这项工作中，我们提出了一个详细的协议，使用成本参考微质喷气机（COST-Jet）进行可靠和可重复的表面处理。讨论了常见的问题和陷阱，以及 COST-Jet 与其他设备相比的特殊性及其有利的远程特性。提供了固体和液体表面处理的详细描述。所述方法用途广泛，可适用于其他类型的大气压力等离子体设备。

使用上述方法和设备，我们模范地将 COST-Jet 应用于不同的表面和液体。 图1 显示了用于处理的实验设置，包括电源、供气系统、电压和电流探头以及受控大气和机械快门。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/61801/61801fig01.jpg"> 图1:使用COST-Jet对表面和液体进行血浆处理的实验设置。冷陷阱用于净化饲料气体。受控大气由大气压力下的抽吸真空室实现。机械快门可促进固体和液体表面处理的时间管理。灵活的阶段允许控制等离子喷射和表面之间的距离。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/61801/61801fig01large.jpg" target="_blank">请单击此处查看此图的较大版本。</a>
使用 COST-Jet 中实施的电压和电流探头，可以计算耗电的电力。 图2 显示了使用1 slpm的气体流在5个不同的COST-Jet设备中产生的氦等离子体中测得的功率。所有设备都显示类似的行为。不同设备之间的偏差源于功率测量的不确定性以及电极距离等设置的微观差异。Riedel22对活性物种（如原子氧和臭氧）、温度和功率以及杀菌活性进行了更详细的测量。
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/61801/61801fig02.jpg"> 图2:作为氦等离子体中施加电压的函数的耗电。这些数据代表五个相同的成本喷气机设备34。高压下的小偏差是由于测量的不确定性以及气体排放通道几何体22的微小偏差。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/61801/61801fig02large.jpg" target="_blank">请单击此处查看此图的较大版本。</a>
图3 显示了一个:C-H薄膜的蚀刻轮廓，使用1.4 slpm氦气流与使用成像光谱反射仪31测量的0.5%氧的气体流与COST-Jet进行3分钟的治疗。蚀刻图案显示代表等离子体流出的圆柱对称性的圆形结构。根据蚀刻剖面与数值模拟相结合，可以估计原子氧的表面损失概率。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/61801/61801fig03.jpg"> 图3:血浆处理A:C-H胶片的蚀刻轮廓。薄膜中的浸渍是使用 1.4 slm 氦气混合物蚀刻的，在 230 Vrms 的电压下混合 0.6% 的氧气，处理时间为 3 分钟31<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/61801/61801fig03large.jpg" target="_blank">请单击此处查看此图的较大版本。</a>
图4 显示了气体流对液体表面的流动引起的液体中发生的涡流。激光片照亮液体中的微量粒子，通过粒子图像速度观察这些粒子的轨迹和速度，从而研究流体流动32。重要的是要考虑播种颗粒和液体的类似密度，以便粒子的轨迹代表流体的运动。有了这种可视化的流体流量测量和数值模拟可以比较33。涡流是由于污水流和液态气流之间的表面摩擦造成的。 图4 还显示了等离子喷射气体通道（即所谓的半月板）气体通道下方液体表面的凹陷。它通过蓝线可视化。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/61801/61801fig04.jpg"> 图4:由气体流搅拌的3毫升水中发光玉米淀粉颗粒的照片。涡流是由于污水流和液态气流之间的表面摩擦造成的。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/61801/61801fig04large.jpg" target="_blank">请单击此处查看此图的较大版本。</a>

Watch this Scientific Journal Video about Treating Surfaces with a Cold Atmospheric Pressure Plasma using the COST-Jet at JoVE.com

Treating Surfaces with a Cold Atmospheric Pressure Plasma using the COST-Jet

此协议旨在描述 COST-Jet 用于处理各种表面（如固体和液体）的设置、处理和应用。

使用成本喷气机用冷大气压力等离子体处理表面

In recent years, non-thermal atmospheric pressure plasmas have been used extensively for surface treatments, in particular, due to their potential in ...

treating-surfaces-with-cold-atmospheric-pressure-plasma-using-cost

Nanyang Technological University

Research

JoVE Journal

Engineering

3.9K 次观看.  Kiel University. 此协议旨在描述 COST-Jet 用于处理各种表面（如固体和液体）的设置、处理和应用。

视频: Treating Surfaces with a Cold Atmospheric Pressure Plasma using the COST-Jet

Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. Therefore, it is highly desirable to remove biofilms from surfaces. Many studies on CO2 aerosol cleaning have employed nitrogen purges to increase biofilm removal efficiency by reducing the moisture condensation generated during the cleaning. However, in this study, periodic jets of CO2 aerosols without nitrogen purges were used to remove Pseudomonas putida biofilms from polished stainless steel surfaces. CO2 aerosols are mixtures of solid and gaseous CO2 and are generated when high-pressure CO2 gas is adiabatically expanded through a nozzle. These high-speed aerosols were applied to a biofilm that had been grown for 24 hr. The removal efficiency ranged from 90.36% to 98.29% and was evaluated by measuring the fluorescence intensity of the biofilm as the treatment time was varied from 16 sec to 88 sec. We also performed experiments to compare the removal efficiencies with and without nitrogen purges; the measured biofilm removal efficiencies were not significantly different from each other (t-test, p &gt; 0.55). Therefore, this technique can be used to clean various bio-contaminated surfaces within one minute.

Biofilms on surfaces can be effectively and rapidly removed by using a periodic jet of carbon dioxide aerosols without a nitrogen purge.

去除生物膜使用二氧化碳气溶胶没有氮气吹扫

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. ...

科研

环境科学

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 ...

工程学

Basic Research in Plasma Medicine - A Throughput Approach from Liquids to Cells

In plasma medicine, ionized gases with temperatures close to that of vertebrate systems are applied to cells and tissues. Cold plasmas generate reactive species known to redox regulate biological processes in health and disease. Pre-clinical and clinical evidence points to beneficial effects of plasma treatment in the healing of chronic ulcer of the skin. Other emerging topics, such as plasma cancer treatment, are receiving increasing attention. Plasma medical research requires interdisciplinary expertise in physics, chemistry, and biomedicine. One goal of plasma research is to characterize plasma-treated cells in a variety of specific applications. This includes, for example, cell count and viability, cellular oxidation, mitochondrial activity, cytotoxicity and mode of cell death, cell cycle analysis, cell surface marker expression, and cytokine release. This study describes the essential equipment and workflows required for such research in plasma biomedicine. It describes the proper operation of an atmospheric pressure argon plasma jet, specifically monitoring its basic emission spectra and feed gas settings to modulate reactive species output. Using a high-precision xyz-table and computer software, the jet is hovered in millisecond-precision over the cavities of 96-well plates in micrometer-precision for maximal reproducibility. Downstream assays for liquid analysis of redox-active molecules are shown, and target cells are plasma-treated. Specifically, melanoma cells are analyzed in an efficient sequence of different consecutive assays but using the same cells: measurement of metabolic activity, total cell area, and surface marker expression of calreticulin, a molecule important for the immunogenic cell death of cancer cells. These assays retrieve content-rich biological information about plasma effects from a single plate. Altogether, this study describes the essential steps and protocols for plasma medical research.

A high-throughput cold physical plasma treatment protocol of liquids and cells is shown. It involves setting up different feed gas compositions for plasma ignition, measuring the plasma&#39;s emission spectra, and the subsequent analysis of liquids and cellular activity after plasma treatment.

等离子体医学基础研究--从液体到细胞的吞吐量方法

In plasma medicine, ionized gases with temperatures close to that of vertebrate systems are applied to cells and tissues. Cold plasmas generate reactive ...

Experimental Methods of Dust Charging and Mobilization on Surfaces with Exposure to Ultraviolet Radiation or Plasmas

Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using three recently developed experiments in which dust particles are exposed to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. The UV light source has a narrow bandwidth in wavelength centered at 172 nm. The beam electrons with the energy of 120 eV are created with a negatively biased hot filament. When the vacuum chamber is filled with the argon gas, a thermal plasma is created in addition to the electron beam. Insulating dust particles of a few tens of microns in diameter are used in the experiments. Dust particles are recorded to be lofted to a height up to a few centimeters with a launch speed up to 1 m/s. These experiments demonstrate that photo and/or secondary electron emission from a dusty surface changes the charging mechanism of dust particles. According to the recently developed &#34;patched charge model&#34;, the emitted electrons can be re-absorbed inside microcavities between neighboring dust particles below the surface, causing the accumulation of enhanced negative charges on the surrounding dust particles. The repulsive forces between these negatively charged particles may be large enough to mobilize and lift them off the surface. These experiments present the advanced understanding of dust charging and transport on dusty surfaces, and laid a foundation for future investigations of its role in the surface evolution of airless planetary bodies.

Dust charging and mobilization is demonstrated in three experiments with exposure to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. These experiments present the advanced understanding of electrostatic dust transport and its role in shaping the surfaces of airless planetary bodies.

紫外辐射或等离子体照射表面的粉尘充电和动员实验方法

Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using ...

Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution for future high-speed reentry missions. But despite the advancements made since Apollo, heat flux prediction remains an imperfect science and engineers resort to safety factors to determine the TPS thickness. This goes at the expense of embarked payload, hampering, for example, sample return missions. 
Ground testing in plasma wind-tunnels is currently the only affordable possibility for both material qualification and validation of material response codes. The subsonic 1.2MW Inductively Coupled Plasmatron facility at the von Karman Institute for Fluid Dynamics is able to reproduce a wide range of reentry environments. This protocol describes a procedure for the study of the gas/surface interaction on ablative materials in high enthalpy flows and presents sample results of a non-pyrolyzing, ablating carbon fiber precursor. With this publication, the authors envisage the definition of a standard procedure, facilitating comparison with other laboratories and contributing to ongoing efforts to improve heat shield reliability and reduce design uncertainties.
The described core techniques are non-intrusive methods to track the material recession with a high-speed camera along with the chemistry in the reactive boundary layer, probed by emission spectroscopy. Although optical emission spectroscopy is limited to line-of-sight measurements and is further constrained to electronically excited atoms and molecules, its simplicity and broad applicability still make it the technique of choice for analysis of the reactive boundary layer. Recession of the ablating sample further requires that the distance of the measurement location with respect to the surface is known at all times during the experiment. Calibration of the optical system of the applied three spectrometers allowed quantitative comparison. At the fiber scale, results from a post-test microscopy analysis are presented.

Development of new ablative materials and their numerical modeling requires extensive experimental investigation. This protocol describes procedures for material response characterization in plasma flows with the core techniques being non-intrusive methods to track the material recession along with the chemistry in the reactive boundary layer by emission spectroscopy.

烧蚀材料在试验过程中等离子体发生器发射光谱边界层研究

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution ...

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

This article describes a flowing microwave reactor that is used to drive efficient non-equilibrium chemistry for the application of conversion/activation of stable molecules such as CO2, N2 and CH4. The goal of the procedure described here is to measure the in situ gas temperature and gas conversion.

用于高效高温化学的非平衡微波等离子体

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose ...

化学

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. ...

Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface. For example, the influence of the plasma-treatment on different types of membranes (e.g.&#160;polyester, polycarbonate, polyvinylidene fluoride) is studied. Furthermore, the time-dependent stability of the surface-grafted membranes is shown by contact angle measurements. When grafting poly(2-hydroxyethyl methacrylate) (PHEMA) in this way, the surface can be further modified by esterification of the alcohol moiety of the polymer with a carboxylic acid function of the desired substance. These reactions can therefore be used for the functionalization of the membrane surface. For example, the surface tension of the membrane can be changed or a desired functionality as the presented light-responsiveness can be inserted. This is demonstrated by reacting PHEMA with a carboxylic acid functionalized spirobenzopyran unit which leads to a light-responsive membrane. The choice of solvent plays a major role in the postmodification step and is discussed in more detail in this paper. The permeability measurements of such functionalized membranes are performed using a Franz cell with an external light source. By changing the wavelength of the light from the visible to the UV-range, a change of permeability of aqueous caffeine solutions is observed.

A plasma-induced polymerization procedure is described for the surface-initiated polymerization on polymer membranes. Further postmodification of the grafted polymer with photochromic substances is presented with a protocol of conducting permeability measurements of light-responsive membranes.

通过结合表面接枝和修改后的过程光敏感膜的制备

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is ...

生物工程

Cryogenic Liquid Jets for High Repetition Rate Discovery Science

This protocol presents a detailed procedure for the operation of continuous, micron-sized cryogenic cylindrical and planar liquid jets. When operated as described here, the jet exhibits high laminarity and stability for centimeters. Successful operation of a cryogenic liquid jet in the Rayleigh regime requires a basic understanding of fluid dynamics and thermodynamics at cryogenic temperatures. Theoretical calculations and typical empirical values are provided as a guide to design a comparable system. This report identifies the importance of both cleanliness during cryogenic source assembly and stability of the cryogenic source temperature once liquefied. The system can be used for high repetition rate laser-driven proton acceleration, with an envisioned application in proton therapy. Other applications include laboratory astrophysics, materials science, and next-generation particle accelerators.

This protocol presents the operation and principles of micron-scale cylindrical and planar cryogenic liquid jets. Until now, this system has been used as a high repetition rate target in laser-plasma experiments. Anticipated cross-disciplinary applications range from laboratory astrophysics to material science, and eventually next-generation particle accelerators.

用于高重复率发现科学的低温液体射流

This protocol presents a detailed procedure for the operation of continuous, micron-sized cryogenic cylindrical and planar liquid jets. When operated as ...

Investigating the Detrimental Effects of Low Pressure Plasma Sterilization on the Survival of Bacillus subtilis Spores Using Live Cell Microscopy

Plasma sterilization is a promising alternative to conventional sterilization methods for industrial, clinical, and spaceflight purposes. Low pressure plasma (LPP) discharges contain a broad spectrum of active species, which lead to rapid microbial inactivation. To study the efficiency and mechanisms of sterilization by LPP, we use spores of the test organism Bacillus subtilis because of their extraordinary resistance against conventional sterilization procedures. We describe the production of B. subtilis spore monolayers, the sterilization process by low pressure plasma in a double inductively coupled plasma reactor, the characterization of spore morphology using scanning electron microscopy (SEM), and the analysis of germination and outgrowth of spores by live cell microscopy. A major target of plasma species is genomic material (DNA) and repair of plasma-induced DNA lesions upon spore revival is crucial for survival of the organism. Here, we study the germination capacity of spores and the role of DNA repair during spore germination and outgrowth after treatment with LPP by tracking fluorescently-labelled DNA repair proteins (RecA) with time-resolved confocal fluorescence microscopy. Treated and untreated spore monolayers are activated for germination and visualized with an inverted confocal live cell microscope over time to follow the reaction of individual spores. Our observations reveal that the fraction of germinating and outgrowing spores is dependent on the duration of LPP-treatment reaching a minimum after 120 s. RecA-YFP (yellow fluorescence protein) fluorescence was detected only in few spores and developed in all outgrowing cells with a slight elevation in LPP-treated spores. Moreover, some of the vegetative bacteria derived from LPP-treated spores showed an increase in cytoplasm and tended to lyse. The described methods for analysis of individual spores could be exemplary for the study of other aspects of spore germination and outgrowth.