Name: non-equilibrium microwave plasma for efficient high temperature chemistry
Uploaded: 2017-08-01T13:00:00.000+00:00
Duration: 7 min 17 s
Description: Watch this Scientific Journal Video about Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry at JoVE.com

这项工作是由壳牌，该基金会用于基础研究的物质（FOM），以及荷兰科学研究组织（NWO）支持的呼叫"CO 2 -零排放燃料"资助。作者要感谢Eddie van Veldhuizen，Ana Sobota和Sander Nijdam允许我们使用他们的实验室空间和一般的慷慨支持。

注意:有关安装程序的原理图版本，请参见图2 。 微波等离子体实验布局<ol><li>将1 kW磁控管连接到循环器，并附上一个水负荷。 </li><li>将隔离器连接到用于波导与等离子体的阻抗匹配的三管段调谐器。 </li><li>将涂抹器连接到三根调谐器，并在波导的末端添加滑动短路。 </li><li>将17毫米或27毫米内径的石英管放置在敷贴器的孔中。 注:微波吸收包含在该管流动的CO 2气体英寸</li><li>通过将石英管连接到KF法兰和气体入口来完成真空设置。 </li><li>使用KF-16作为17 mm石英管，KF-40用于27 mm石英管。使用切向气体入口以引起涡流，这防止热等离子体接触壁。 </li><li> CONNECta节流阀与真空泵串联;这允许通过有效地调节泵送速度来将压力从5mbar改变到大气压力。 </li><li>与节流阀并联，连接快捷阀，在低压（要求等离子体点火所需）和高压之间切换，而不会损失节气门的压力设定。 </li><li>将质量流量控制器连接到气体入口，使气体流量可调节在0.5和10.0 SLM之间。 </li><li>在启动等离子体之前打开磁控管的水冷。 </li><li>确保启用安全系统，例如用于监测杂散微波辐射的辐射计和用于监测环境CO，H 2或NO x浓度的气体检测器。这些安全系统在实验中是必不可少的</li><li>通过手动打开电源的功率电平并增加到最大功率来打开电源。 </li><li>调整pl通过稍微移动它，而不断监测反射功率是否下降。目的是尽量减少反射功率。通过转动它们来调整三根调谐器，直到反射功率最小化。如果网络分析仪可用，请按照Leinz 10报告的步骤进行。 注:真空和微波系统在图3 中可见。 </li></ol>瑞利散射诊断的光学布局<ol><li>将532 nm Nd:YAG激光束与使用反射镜对齐，使其轴向进入。激光器具有10Hz的重复率和每脉冲600mJ的最大功率。 </li><li>在反应堆的相对侧（入口和出口）安装窗户。使用抗反射（AR）涂层的窗口532 nm，以防止过多的杂散光。或者，使用布鲁斯特窗口与外部光束转储组合。 </li><li>开始激光按照用户手册（见表格材料 ）。 </li><li>使用低输出功率程序对准激光。从0μs的Q开关延迟开始，不会产生光输出。然后以5μs的步长增加延迟，直到光输出可见。 </li><li>如果光束太亮，则以1μs为单位，以达到"足够"的亮度， 即光斑仍然可见的最低功率。 </li><li>在真空系统的激光束出口​​侧安装第二个AR涂层窗口，将光束转移到外部光束转台上。或者，代替窗口，安装真空射束。设置的原理图可以在图2中看到。 注意:消除窗口减少等离子体放电区域中的杂散光，这对于实现可检测的瑞利散射信号电平至关重要。 </li><li>放置焦距2.4的镜头m在光束路径中，就在入口窗口之前，将激光聚焦到波导的中心。长焦距减少瑞利散射收集区域中的杂散光。将镜头尽可能靠近窗户以降低入射功率密度，使其保持在窗口的损坏阈值以下。 注意:防止气体中的激光击穿，特别是在激光对焦中。聚焦激光后，在高于待测压力的压力下将CO 2流入反应器中。如果没有观察到激光击穿，则在不断发生测量的较低压力和较高的温度下，因为物种的密度要低得多。如果听到伴随着可见的蓝色闪烁的声音，会发出大声的咔哒声，降低了激光功率。 </li><li>在真空管内部安装规则间隔的挡板，以进一步减少等离子体放电区域中由于入口处的散射引起的杂散光水平<li>准备一个直径24毫米的柱塞，用于垂直于激光束的光学访问。有限的孔径防止显着的微波辐射损失。 </li></ol>光学设置 - 检测分支<ol><li>放置一个透镜（F = 100毫米，51毫米直径）垂直于所述反应器中并通过在所述柱塞孔收集的散射光， 如图3 所述 。将光聚焦到400μm直径的光纤上，并将其放置在镜头图像中。 注意:纤维位于59个熔融石英纤维的线性阵列中，输入高度为26.7毫米，长度为40米。 </li><li>使用光纤将光引导到光谱仪。 注意:这里将光线成像到入口狭缝上，宽度可调至10μm。收集光学器件的放大率导致约2的轴向检测范围0毫米。使用光谱仪过滤出重合的C 2天鹅发射。如果实验者只对瑞利散射感兴趣，那么也可以使用合适的带通滤波器。在这种情况下，可以跳过步骤3.3至3.6。通过比较测量的光强度和无激光脉冲，可以完全消除光谱滤波器，大大简化了光学设置。如果单色仪被消除，则不可能将测量结果扩展到需要光谱分辨率的汤姆逊或拉曼散射。 </li><li>使用光谱仪（在室内）光谱解析散射光。 注意: 如图2所示 ，光谱仪由入口狭缝，导向镜，Littrow透镜，色散光栅，图像增强器，聚焦透镜和CCD相机组成。 </li><li>在光谱仪内部，放置一个镜子，用af反射入射到Littrow镜头的光眼距离为0.3μm，直径为80mm。 注意:光谱仪处于"Littrow"配置，这意味着入射和衍射光与光栅法线具有相同的角度。因此，使用相同的透镜来准直入射光并将衍射光成像到检测器上。 </li><li>旋转舞台上的衍射光栅旋转到适当的波长范围。对于Nd:YAG激光器，其通常在524和540nm之间。光栅为11×11cm 2，并且具有针对一阶衍射优化的槽密度为1,200mm -1 。这导致0.027nm / px的分辨率。 图 3B显示了光栅和Littrow透镜的图像。 注意:由于高阶，光栅将成像多个斑点;确保只有1个最大的图像增强器结束。 </li><li>放置两个镜头成像加强的l在CCD摄像机上（ 图3 C ）。 </li><li>量化杂散光贡献。泵送至60 mbar的压力，并测量散射强度。降低压力并再次测量强度。重复此操作，直到压力不能进一步降低。 </li><li>绘制强度与压力时，确保存在线性关系。将线性函数推挤到零压力。 注意:由于在零压力下不能发生瑞利散射，截距处的强度是杂散光水平。该过程的结果如图4所示。 </li><li>调整图像增强器的门控参数，以优化CCD记录的强度。从激光脉冲之后开始的栅极脉冲开始，并在激光脉冲之后结束，从而捕获整个激光脉冲。 </li><li>考虑到光线具有t时光的飞行时间延迟o穿过整个光学设置。减少延迟，同时确保强度不降低。 注意:发现30 ns的时间窗口对于9 ns脉冲是足够的。要增加增益，请将多通道板电压增加到最大电压（这里为850 V）。如果CCD相机曝光过度，则可以选择更小的多通道板电压。 </li></ol> FTIR光谱仪<ol><li>将FTIR光谱仪置于等离子体下游的气体排气中，以测量CO生产率。将光谱仪放置在离反应器足够远的地方，以确保气体处于化学平衡状态。在所述的装置中，距等离子体的距离为2m。 </li><li>将电池放在FTIR光谱仪的样品室中，内部和外部波纹管与真空系统串联连接。这在图5中示意性地示出。 </li><li>在单元格的每一侧安装一个CaF 2窗口以允许IR光束探测气体。 </li><li>改变信号增益，直到信号强度尽可能接近最大值，但不超过它。最大允许强度可能因设备而异。 </li><li>点击&#39;干涉图&#39;预览。干涉图现在可见，中心有高峰，肩部强度低。 </li><li>开始测量前，在真空（&lt;0.1 mbar）下测量背景。要做到这一点，确保反应堆处于真空状态，没有气体流动;然后通过单击"信号电平监视器"窗口中的"背景"来记录背景。 </li><li>通过将功率增加到最大值来打开微波炉，直到等离子体点燃。用于等离子体点火的压力为〜1毫巴。 </li><li>记录在2,400至2000厘米-1范围内的光谱;这包括CO和主CO 2带。 </li><li>平均光谱以减少噪音;值100;平均值用于本实验。使用HITRAN数据库12对测量的CO线进行拟合。 注意:这导致CO体积分数。测量压力并将其用作输入参数以找出总密度。假定温度为室温，这是通过光谱中的振动峰的分布来证明的。 </li><li>为了测量原位光谱，将反应器置于样品室内， 如图6 和7所示 。 </li><li>切换到蓝宝石而不是石英管，以进行径向测量。蓝宝石将红外光传输到1800厘米-1 。 </li><li>通过原位测量，使用大量平均值至少为100来平均等离子体的波动。 </li><li>用微波吸收材料装饰隔间壁，以减少杂散微波辐射（此处使用Eccosorb OCF ））。 </li><li>由于等离子体的额外的IR发射，干涉图不会饱和。如果是这种情况，请更改检测器的直流偏移。校正蓝宝石13温度依赖性吸收光谱。 </li><li>如果使用红外摄像机测量温度，请使用在蓝宝石不透明（ 即高于6μm）的范围内敏感的照相机，以便测量管温而不是等离子体。 注意:蓝宝石作为温度的函数吸收的推荐值可以在14中找到。 </li></ol>

<ol>
	<li>Itikawa, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonresonant+Vibrational+Excitation+of+CO2+by+Electron+Collision.">Nonresonant Vibrational Excitation of CO2 by Electron Collision.</a> Phys Rev A. 3 (2), 831-832 (1971).</li><li>Rusanov, V. D., Fridman, A. A., Sholin, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+physics+of+a+chemically+active+plasma+with+nonequilibrium+vibrational+excitation+of+molecules.">The physics of a chemically active plasma with nonequilibrium vibrational excitation of molecules.</a> Phys Usp. 24 (6), 447-474 (1981).</li><li>Fridman, A. A., Kennedy, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Plasma Physics and Engineering. , (2004).</li><li>Witteman, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The CO2-laser. , (1987).</li><li>Fridman, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> A Plasma Chemistry. , (2008).</li><li>Treanor, C. E., Rich, J. W., Rehm, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vibrational+Relaxation+of+Anharmonic+Oscillators+with+Exchange-Dominated+Collisions.">Vibrational Relaxation of Anharmonic Oscillators with Exchange-Dominated Collisions.</a> J Chem Phys. 48 (4), 1798-1806 (1968).</li><li>den Harder, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Homogeneous+CO2+conversion+by+microwave+plasma:+Wave+propagation+and+diagnostics.">Homogeneous CO2 conversion by microwave plasma: Wave propagation and diagnostics.</a> Plasma Process Polym. , (2016).</li><li>van Rooij, G. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taming+microwave+plasma+to+beat+thermodynamics+in+CO2+dissociation.">Taming microwave plasma to beat thermodynamics in CO2 dissociation.</a> Farad Discuss. 183, 233-248 (2015).</li><li>Bongers, W. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma-driven+dissociation+of+CO2+for+fuel+synthesis.">Plasma-driven dissociation of CO2 for fuel synthesis.</a> Plasma Process. Polym. , (2016).</li><li>Leins, M., Gaiser, S., Schulz, A., Walker, M., Schumacher, U., Hirth, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+Ignite+an+Atmospheric+Pressure+Microwave+Plasma+Torch+without+Any+Additional+Igniters.">How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters.</a> J Vis Exp. (98), e52816 (2015).</li><li>van der Meiden, H. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+sensitivity+imaging+Thomson+scattering+for+low+temperature+plasma.">High sensitivity imaging Thomson scattering for low temperature plasma.</a> Rev Sc. Instrum. 79 (1), 13505-13700 (2008).</li><li>Rothman, L. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+HITRAN+2012+Molecular+Spectroscopic+Database.">The HITRAN 2012 Molecular Spectroscopic Database.</a> J Quant Spectrosc. Radiat Transfer. 130, 4-50 (2013).</li><li>Depraz, S., Perrin, M. Y., Soufiani, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infrared+emission+spectroscopy+of+CO2+at+high+temperature.+Part+I:+Experimental+setup+and+source+characterization.">Infrared emission spectroscopy of CO2 at high temperature. Part I: Experimental setup and source characterization.</a> J Quant Spectrosc Radiat Transfer. 113, 1-13 (2011).</li><li>Dobrovinskaya, E. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Sapphire: Material, Manufacturing, Applications. , 170 (2009).</li><li>Sneep, M., Ubachs, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+measurement+of+the+Rayleigh+scattering+cross+section+in+various+gases.">Direct measurement of the Rayleigh scattering cross section in various gases.</a> J Quant Spectrosc Radiat Transfer. 92 (3), 293-310 (2005).</li><li>Sutton, J. A., Driscoll, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rayleigh+scattering+cross+sections+of+combustion+species+at+266,+355,+and+532+nm+for+thermometry+applications.">Rayleigh scattering cross sections of combustion species at 266, 355, and 532 nm for thermometry applications.</a> Optics Letters. 29 (22), 2620-2622 (2004).</li><li>Penney, C. M., Peters, R. L., Lapp, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absolute+raman+cross+sections+for+N2.">Absolute raman cross sections for N2.</a> J Opt Soc Am. 64 (5), 712-716 (1974).</li><li>Murphy, A. B., Farmer, A. J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+measurement+in+thermal+plasmas+by+Rayleigh+scattering.">Temperature measurement in thermal plasmas by Rayleigh scattering.</a> J Phys D: Appl Phys. 25 (4), 634 (1992).</li><li>Snyder, S. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+gas-temperature+and+velocity+profiles+in+an+argon+thermal-plasma+jet+by+laser-light+scattering.">Determination of gas-temperature and velocity profiles in an argon thermal-plasma jet by laser-light scattering.</a> Phys Rev E. 47 (3), 1998-2005 (1993).</li><li>Limbach, C., Dumitrache, C., Yalin, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+Light+Scattering+from+Equilibrium,+High+Temperature+Gases:+Limitations+on+Rayleigh+Scattering+Thermometry.">Laser Light Scattering from Equilibrium, High Temperature Gases: Limitations on Rayleigh Scattering Thermometry.</a> 47th AIAA Plasmadynamics and Lasers Conference. , (2016).</li><li>Wiles, C., Watts, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+flow+reactors:+a+perspective.">Continuous flow reactors: a perspective.</a> Green Chem. 14, 38-54 (2012).</li><li>Cormier, J. M., Rusu, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Syngas+production+via+methane+steam+reforming+with+oxygen:+plasma+reactors+versus+chemical+reactors.">Syngas production via methane steam reforming with oxygen: plasma reactors versus chemical reactors.</a> J Phys D: Appl Phys. 34, 2798-2803 (2001).</li><li>Liu, C. J., Xu, G. H., Wang, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-thermal+plasma+approaches+in+CO2+utilization.">Non-thermal plasma approaches in CO2 utilization.</a> Fuel Process Technol. 58 (2-3), 119-134 (1999).</li><li>Wen, Y., Jiang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decomposition+of+CO2+using+pulsed+corona+discharges+combined+with+catalyst.">Decomposition of CO2 using pulsed corona discharges combined with catalyst.</a> Plasma Chem Plasma Process. 21 (4), 665-678 (2001).</li><li>Mikoviny, T., Kocan, M., Matejcik, S., Mason, N. J., Skalny, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+study+of+negative+corona+discharge+in+pure+carbon+dioxide+and+its+mixtures+with+oxygen.">Experimental study of negative corona discharge in pure carbon dioxide and its mixtures with oxygen.</a> J Phys D: Appl Phys. 37 (1), 64 (2004).</li><li>Horvath, G., Skaln'y, J. D., Mason, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FTIR+study+of+decomposition+of+carbon+dioxide+in+dc+corona+discharges.">FTIR study of decomposition of carbon dioxide in dc corona discharges.</a> J Phys D: Appl Phys. 41 (22), 225207 (2008).</li><li>Bak, M. S., Im, S. K., Cappelli, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanosecond-pulsed+discharge+plasma+splitting+of+carbon+dioxide.">Nanosecond-pulsed discharge plasma splitting of carbon dioxide.</a> IEEE Trans Plasma Sci. 43 (4), 1002-1007 (2015).</li><li>Taylan, O., Berberoglu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissociation+of+carbon+dioxide+using+a+microhollow+cathode+discharge+plasma+reactor:+effects+of+applied+voltage,+flow+rate+and+concentration.">Dissociation of carbon dioxide using a microhollow cathode discharge plasma reactor: effects of applied voltage, flow rate and concentration.</a> Plasma Sources Sci Technol. 24 (1), 015006 (2015).</li><li>Yamamoto, A., Mori, S., Suzuki, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scale-up+or+numbering-up+of+a+micro+plasma+reactor+for+the+carbon+dioxide+decomposition.">Scale-up or numbering-up of a micro plasma reactor for the carbon dioxide decomposition.</a> Thin solid films. 515 (9), 4296-4300 (2007).</li><li>Paulussen, S., Verheyde, B., Tu, X., De Bie, C., Martens, T., Petrovic, D., Bogaerts, A., Sels, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conversion+of+carbon+dioxide+to+value-added+chemicals+in+atmospheric+pressure+dielectric+barrier+discharges.">Conversion of carbon dioxide to value-added chemicals in atmospheric pressure dielectric barrier discharges.</a> Plasma Sources Sci Technol. 19 (3), 034015 (2010).</li><li>Brehmer, F., Welzel, S., van de Sanden, M. C. M., Engeln, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CO+and+byproduct+formation+during+CO2+reduction+in+dielectric+barrier+discharges.">CO and byproduct formation during CO2 reduction in dielectric barrier discharges.</a> J Appl Phys. 116 (12), 123303 (2014).</li><li>Yu, Q., Kong, M., Liu, T., Fei, J., Zheng, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+the+decomposition+of+CO2+in+a+dielectric+packed-bed+plasma+reactor.">Characteristics of the decomposition of CO2 in a dielectric packed-bed plasma reactor.</a> Plasma Chem Plasma Process. 32 (1), 153-163 (2012).</li><li>Aerts, R., Somers, W., Bogaerts, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+Dioxide+splitting+in+a+dielectric+barrier+discharge+plasma:+A+combined+experimental+and+computational+study.">Carbon Dioxide splitting in a dielectric barrier discharge plasma: A combined experimental and computational study.</a> Chem Sus Chem. 8 (4), 702-716 (2015).</li><li>Indarto, A., Yang, D. R., Choi, J. -. W., Lee, H., Song, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gliding+arc+plasma+processing+of+CO2+conversion.">Gliding arc plasma processing of CO2 conversion.</a> J Hazard Mater. 146 (1), 309-315 (2007).</li><li>Nunnally, T., Gutsol, K., Rabinovich, A., Fridman, A., Gutsol, A., Kemoun, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissociation+of+CO2+in+a+low+current+gliding+arc+plasmatron.">Dissociation of CO2 in a low current gliding arc plasmatron.</a> J Phys D: Appl Phys. 44 (27), 274009 (2011).</li><li>Indarto, A., Choi, J. -. W., Lee, H., Song, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conversion+of+CO2+by+gliding+arc+plasma.">Conversion of CO2 by gliding arc plasma.</a> Environ Eng Sci. 23 (6), 1033-1043 (2006).</li><li>Rusanov, V. D., Fridman, A. A., Sholin, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+physics+of+a+chemically+active+plasma+with+non-equilibrium+vibrational+excitation+of+molecules.">The physics of a chemically active plasma with non-equilibrium vibrational excitation of molecules.</a> Sov Phys Usp. 24 (6), 447 (1981).</li><li>Butylkin, I. u. P., Zhivotov, V. K., Krasheninnikov, E. G., Krotov, M. F., Rusanov, V. D., Tarasov, I. u. V., Fridman, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma-chemical+process+of+CO2+dissociation+in+a+nonequilibrium+microwave+discharge.">Plasma-chemical process of CO2 dissociation in a nonequilibrium microwave discharge.</a> Zh Tek Fiz. 51, 925-931 (1981).</li><li>Will, S., Schraml, S., Leipertz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-dimensional+soot-particle+sizing+by+time-resolved+laser-induced+incandescence.">Two-dimensional soot-particle sizing by time-resolved laser-induced incandescence.</a> Opt Lett. 20, 2342-2344 (1995).</li><li>Lepoutre, F., Louis, G., Manceau, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collisional+relaxation+in+CO2+between+180+K+and+400+K+measured+by+the+spectrophone+method.">Collisional relaxation in CO2 between 180 K and 400 K measured by the spectrophone method.</a> Chem Phys Lett. 48, 509-514 (1977).</li></ol>

作者宣称他们没有竞争的经济利益。

<html>为了化学工业的电气化和减轻可再生能源的间歇性，连续流动反应堆是在可持续发展的系统中驾驶化学物质所必需的。已经认识到，连续流动反应堆将在化学工业革命中发挥重要作用21 。更具体地说，等离子体反应器由于其简单性，紧凑性和低价格22而被鉴定为生产CO 2中性燃料的化学工厂的商业上有吸引力的替代品。宽范围的等离子技术的已经提出了用于CO 2 23的离解，其中包括电晕放电24，25，26，纳秒脉冲放电27，微空心阴极放电28，微等离子体"外部参照"&gt; 29，电介质势垒放电30，31，32，33，滑翔弧34，35和微波等离子体37,38。在这些变化很大的技术中，微波等离子体和滑翔弧已经在功率范围内以最高功率运行，并且具有最佳效率，40％的滑动弧和60-80％的微波放电。微波等离子体和滑动电弧反应堆都可以在高功率下运行，这是为了实际应用而投入的最大〜100kW的必要条件。微波等离子体的操作不限于CO 2解离，也可用于甲烷重整和固氮。微波反应器的主要缺点是低压在最佳条件下（100 mbar），这限制了最大的气体通量。 所述方法用CO 2证实，但可以不改变地用于活化CH 4 ，N 2或其它稳定分子。在大多数情况下，需要测量与NH 3 ，NO x ，C 2 H 2 ，C 2 H 4 等预期产品相对应的不同红外波段。运行甲烷等离子体可能比较麻烦的反应产物 - 被沉积到壁上并将吸收微波，有效地熄灭等离子体。虽然振动泵是少得多的甲烷比因为高VT-传输速率的在CO 2有效，等离子体催化仍可以是甲烷有利（弗里德曼5，p.688） 在a中难以实现精确的瑞利散射测量烟灰形成等离子体由于在烟灰颗粒上的三重散射而导致的杂散光贡献高。尽管它使瑞利测量复杂化，但可用于量化烟灰颗粒的密度而不是39 。拉曼散射可以在这种环境中提供测量温度的有吸引力的替代方案，因为它允许光谱区分杂散光和（拉曼）散射光分量。拉曼散射的积分时间约为20分钟，使得等离子体的波动平均。只有像系统加热这样的长期效应才能影响测量，因为它稍微增加了反应堆的压力。 正是由于杂散光和瑞利散射光之间的光谱重叠较大，所以杂散光抑制（即使没有烟灰）的重要性也不容忽视。杂散光可以适当减少放置挡板，增加激光的焦距和设置长度，并增加管径。使用真空束的进一步减少杂散光的水平，因为它消除了出口窗口。或者，也可以使用布鲁斯特窗口。如前所述，需要（测量或模拟）组成的一些知识以适当地说明不同的瑞利横截面。 流动的微波等离子体已经被证明是一种可行的方法，其能量效率高达50％，快速切换的灵活性，并且仅使用便宜的材料。然而，中心的记录温度远高于有利于高振动过度的人群。通过降低温度，可以达到更高的能量效率。尽管降低功率（ 例如 ，到200W）会降低气体温度，而不需要额外优化反应器也降低了效率。 这里提出另外两种降低温度的方法。第一种方式是脉冲微波功率。通过以更短的脉冲施加功率而不是典型的VT-弛豫时间，气体可以在脉冲之间冷却，结果在VT松弛中损失较少的功率。这反过来意味着更多的力量投入振动泵送，促进有效的解离。 VT-松弛时间在室温下为70μs，在100mbar 40时 ，作为脉冲接通时间的上限。脉冲只能提高主要转化途径是通过非平衡转化的血浆方式的效率。提高效率的第二种方法是添加碱性杂质来定制EEDF 8 。通过控制EEDF，特别是电子温度，电子可以更有效地将其能量转移到分子振动h再次导致促进高效反应所必需的较高振动水平。

本文介绍了一种流量微波等离子体高达1 kW的方案，同时测量等离子体气体温度和CO 2转换。 气候变化的担忧以及随之而来的可持续发展意识促使全球可再生能源份额的稳步增长。然而，太阳能和风能的间歇性给能源系统带来压力，阻碍了进一步的部署。需要储存（长期和短期）和转化（ 如化学燃料）以减轻间歇性，并为其他行业（如运输）提供可持续的能源。在反应器中生产的CO可以用作合成例如甲烷或液体燃料的原料气体。通过使用这些来燃料发电厂，即使可再生能源的瞬时生产低，也可能产生电力。即在这些PLA产生的CO 2nts形成闭环，使大气中不会引入净CO 2 ，使其成为清洁循环。 如果切换时间小于能量供应的波动，则系统只能减轻间歇性。在本配置中，启动时间由在理想击穿条件下启动的需要确定，然后调谐到最佳转换条件。原则上，这可以通过其他手段点燃，如聚焦激光或火花来克服。等离子体物理限制大约为0.1毫秒。这比典型的大气效应的时间尺度短得多， 例如云层在太阳能电池板阵列上移动。从目前的系统推广到可持续燃料生产环境中的实际应用仍然是相当长的一年。理想情况下，将有一系列100-500 kW的微波反应堆，每个微波反应堆都连接到太阳能电池板领域或风力发电机，并且可以切换个别的根据能源供应。 本文讨论了一种通常适用于稳定分子如CO 2 ，N 2和CH 4的转化/活化的等离子体方法。在此，作为化学燃料合成的第一步骤，通过CO 2还原为CO的具体实例来引入。流动的微波等离子体反应器适用于解决间歇性问题，因为启动时间低，可以使用廉价的材料制造。 在微波等离子体中，自由等离子体电子与微波的振荡电场一起移动。随后通过碰撞将能量转移到重颗粒（中性和电离气体物质）。由于其质量差异大，该反应器主要在弹性碰撞中有效。首先是电离。在稳定状态下，电离速率基本上等于由于推荐的损失bination。然而，如表1所示，电离能通常明显高于解离能，这使得通过电离的解离固有地低效。同样，电子轰击解离涉及大于10eV 1的能量阈值，并且本来也是低效率的。等离子体相仍然是实现分子解离的有效机制的原因是振动模式的有效激发2 。 在微波等离子体3中常见的几个eV的平均电子能量下，振动激发是主要的能量传递途径。非对称拉伸是特别重要的，因为它可以通过分子间碰撞在较高水平之间快速分配能量。能量交换率随温度而升高， ΔE越大，Δt越大o振动梯子中的非谐波和两个相邻振动模式的相关小能量差异4 。升高的振动水平可以一直到解离，这导致能量有效的解离反应5 。 CO 2中的高振动泵送导致更高的振动模式比热平衡中更多的振动模式，最终产生所谓的Treanor分布6 。实现更高振动水平的人群的条件是振动振动（VV）松弛率远高于振动（VT）松弛率。这是CO 2的不对称拉伸模式的情况。 VV松弛率随着气体温度的升高而降低，VT速率增加。由于VT松弛增加了气体温度正反馈机制可以产生失控的VT弛豫，导致过高的振动水平的破坏。换句话说，低气体温度有利于强烈的非热分布。 实际上，等离子体对于不同的物种及其自由度将呈现明显不同的温度。在几个eV的典型电子温度下，振动温度将为几千摄氏度，而平移（气体）温度可能保持低于千摄氏度。这种情况被认为是强非平衡的 ，已被认为有利于化学反应。 翻译气体温度，因为对等离子体可能驱动化学反应的能量效率如此重要，需要精确和空间分辨的诊断。发射光谱是基线<html>等离子体物理学中的方法来推断温度。例如，可以使用杂质评估旋光谱以获得最佳诊断。然而，这总是涉及视线整合，因此平均。正如我们将在本文中看到的，温度梯度必须陡峭，因为高达〜4000K的高中心温度和由约500K的壁确定的边缘温度。在这种情况下，局部测量是无价的。 在本工作中，瑞利散射的局部密度测量结合压力测量结果，通过理想气体定律来推断温度。瑞利散射测量涉及将高功率激光聚焦在样品体积中，从而从中检测到CO 2分子的结合电子上的光子的弹性散射。气体温度与瑞利信号的强度有关: on 1"src ="/ files / ftp_upload / 55066 / 55066eq1.jpg"/&gt; 这里T是气体温度， p是由压力表测量的压力， I是测量的瑞利强度， dσ/dΩ（T）是瑞利横截面， C是校准常数。由于横截面dσ/dΩ（T）是物种依赖的，我们看到，对于高温度，其中解离是显着的，校准常数是温度的函数。假设在热中心，仅进行平衡转化，从而可以计算给定温度下的物质浓度。以这种方式，一个可以用数值计算对于给定温度，其被用于计算中的预期的范围内的温度下7的将被测量的瑞利强度的有效横截面。这个有效截面作为温度的函数如图1所示</st<html>荣&gt;。 通过FTIR的手段量化等离子体转换的性能。在目前的CO 2还原的情况下，假设等离子体中的净反应为: <img alt="公式2" src="/files/ftp_upload/55066/55066eq2.jpg" />这允许使用与CO体积分数相关的单一转换因子α <img alt="公式3" src="/files/ftp_upload/55066/55066eq3.jpg" /> ， 其来自从FTIR光谱中CO和CO 2的光谱特征推断的浓度。我们注意到，由FTIR确定的整体转换系数不能轻易地推导出有效的瑞利截面。整体转换不仅由中央反应堆温度决定，而且还由气体温度的实际径向剖面中的微妙设定。 ove_content"&gt;本文详细介绍了我们提出的微波等离子体化学气体转化表征的诊断方案，并说明了其教学人员的选择范例。在评估反应堆的气体流量，压力和微波功率方面的全参数扫描可以在7，8，9。

<table><tbody><tr><td>1kW magnetron</td><td>Muegge</td><td>MW-GIRYJ1540-1K2-08</td><td></td></tr><tr><td>Circulator with water load</td><td>Philips</td><td>2722 163 02101</td><td></td></tr><tr><td>3-stub tuner</td><td>IBF-electronic</td><td>WR340PTUN3AC174A</td><td></td></tr><tr><td>Applicator with sliding short</td><td>homemade</td><td></td><td></td></tr><tr><td>17mm ID / 20 mm OD Quartz tube</td><td>Saillart</td><td>custom</td><td></td></tr><tr><td>27mm ID / 30 mm OD Quartz tube</td><td>Saillart</td><td>custom</td><td></td></tr><tr><td>18mm ID / 20 mm OD Sapphire tube</td><td>Precision Sapphire Technologies</td><td>custom</td><td></td></tr><tr><td>KF-vacuum flanges</td><td>Hositrad</td><td></td><td></td></tr><tr><td>Mass flow controller</td><td>Tylan/Brooks</td><td>FC-2901V-4V</td><td></td></tr><tr><td>MFC control unit</td><td>MKS</td><td>PR-3000</td><td></td></tr><tr><td>Pressure guage</td><td>Edwards</td><td>ASG-2000</td><td></td></tr><tr><td>Vacuum pump</td><td>Edwards</td><td>E2M18</td><td></td></tr><tr><td>Nd:YAG laser</td><td>Continuum</td><td>Powerlite DLS 8000</td><td></td></tr><tr><td>AR-coated window</td><td>Eksma Optics</td><td>210-1202E + 3025-i0 (coating)</td><td></td></tr><tr><td>Diffraction grating</td><td>Jobin Yvon</td><td>520-25-120</td><td></td></tr><tr><td>Image Intensifier</td><td>Katod</td><td>EPM102G-04-22S</td><td></td></tr><tr><td>Intensifier power source</td><td>homemade</td><td></td><td></td></tr><tr><td>Spectrometer lens 1</td><td>Nikon</td><td>135mm f/2 DC</td><td></td></tr><tr><td>Spectrometer lens 2</td><td>Nikon</td><td>AF-S 85 mm f/1.8g</td><td></td></tr><tr><td>CCD-camera</td><td>Allied Optics</td><td>Manta G-145B</td><td></td></tr><tr><td>FTIR-spectrometer (exhaust)</td><td>Varian/Agilent</td><td>Cary 670</td><td></td></tr><tr><td>FTIR-spectrometer (in-situ)</td><td>Bruker</td><td>Vertex 80v</td><td></td></tr><tr><td>CaF2 windows</td><td>Crystran</td><td>CAFP25-2U</td><td></td></tr></tbody></table>

non-equilibrium microwave plasma for efficient high temperature chemistry

讨论了用于将电能转化为稳定分子的内部和/或平移模式的流动微波等离子体方法，以有效地驱动非平衡化学。流动等离子体反应器的优点在于连续的化学过程可以以秒级时间内的启动时间的灵活性来驱动。等离子体方法通常适用于稳定分子如CO 2 ，N 2和CH 4的转化/活化。这里将CO 2还原为CO用作模型系统:互补诊断说明了如何通过高振动激发的固有非平衡来超过基线热力学平衡转化。激光（瑞利）散射用于测量反应器温度和傅立叶变换红外光谱（FTIR），以表征原位内部（振动）激发以及eff透明组合物来监测转化率和选择性。

在本节中，介绍了流动等离子体反应器的代表性结果。发现CO转化率显示出以比能量线性增加，直到约为2.2eV /分子。能量η计算如下: <img alt="公式4" src="/files/ftp_upload/55066/55066eq4.jpg" />这里α是测量的转化率， q分子气体流量， ΔE= 2.7 eV的净解离能， P 在输入功率。通过使用测量的转换（在下一段落解释），我们可以发现在等离子体反应器，其被绘制各种压力和权力的，并且在图8A 和图8B 13 SLM的固定流速的能量效率。等离子体能够将CO 2转化为CO，能量效率高达49％，这与最大的热力学效率相当5 。尽管这里报道的效率接近于热解离的效率，但是证明非平衡等离子体可以产生比在所测量的平移温度下的平衡中更高的CO体积分数。与热解离相比的优点在于反应可以转变在几秒钟内开启或关闭，这是减轻波动电力生产所需要的。此外，还有可能通过定制电子能量分布函数（EEDF）进一步提高效率。 我们现在专注于为废气获得的结果。 CO浓度通过IR吸收光谱测定。在图9A 和9B中 ，示出了代表性的光谱。合适的结果在一个te温度为299.36K，转化率为14.7％。测量数据（蓝色）与拟合数据（绿色）良好比较。由于排气中的温度接近室温，因此在拟合过程中可以将温度作为固定参数。接下来讨论原位测量。当解释瑞利光强度，就必须考虑到的是，反应产物的瑞利截面- CO，O和O 2 -显著从CO 2 15，16的不同。仅当样品体积组成的信息可用时，才能解决此问题。如果可以记录拉曼光谱，建议监测CO分子的拉曼光谱，以估算产物的局部数密度。在这种情况下可以使用偏振器来消除杂散光，汤姆森和瑞利散射，同时降低旋转体的强度拉曼散射光仅为因子3/7 17 。如果拉曼光谱不能被测量，因为瑞利峰没有充分降低，转换可以基于平衡转化（见参考文献7，20）来估计。虽然这忽略了由于非平衡条件引起的生产增加，但是气体温度足够高以证明这种简化。在图10中 ，显示了包括不同瑞利横截面的温度数据。已经发现，对于等离子体没有任何优化，等离子体中心中的气体可以达到高达5000K的温度。已经显示在Ar等离子体中，如果温度达到顺序，则来自激发物种的汤姆森散射和散射变得显着10000ķ18，19，20，使得温度测量不可靠。给定Rayleigh和Thomson散射的差分截面值分别为0.148±10 -30 m 2和7.94±10 -30 m 2 ，对于汤姆森贡献1，电离度为1.9·10 -4是必需的％。这比电离度预测为存在于血浆中高得多的1·10 -6至8×10 -5（5弗里德曼，P294）。 原位 FTIR测量为2.0slm的流量和5mbar的显着较低的压力以形成均匀的等离子体，这确保了可靠的路径集成测量。这也意味着等离子体本身接触并加热了墙壁。为了防止壁变得太热，则功率减小到只有30 W.虽然CO-生产是在这样低的功率和压力可忽略不计， 在原位FTIR仍然提供了相关的见解入CO 2等离子体的动态。以0.125cm -1的分辨率记录光谱。频谱配备了基于HAPI（HITRAN 12的应用编程接口）的模型。代码被修改为包括不同振动正常模式的单独温度。对称拉伸和弯曲模式都使用单个温度T 12 ，因为费米共振保证了两种正常模式之间的快速松弛。 拟合的结果为T = 700 K，T 12 = 1250 K，和T 3 = 1500 K， 如图11。安装压力为10毫巴。这个过高估计可能会补偿压力增宽常数的低估温度系数。用瑞利散射发现的气体温度可以与o不同ne发现FTIR，因为瑞利散射测量局部温度，而FTIR光谱是线性集成的。 <img alt="图1" class="xfigimg" src="/files/ftp_upload/55066/55066fig1.jpg" /> 图1 :瑞利横截面的温度依赖性 来自反应产物的不同横截面的瑞利横截面。假设热平衡中的转化计算相对物质摩尔分数。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig1large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图2" class="xfigimg" src="/files/ftp_upload/55066/55066fig2.jpg" /> 图2 :瑞利测量的光学设置 镜头focu将激光照射到石英管中心。波导将微波发射到等离子体中，定位在激光的焦点中。柱塞中的一个孔为激光器和弦提供光学访问。光谱仪包括（1）入口狭缝，（2）转向镜，（3）Littrow透镜，（4）色散光栅，（5）图像增强器，（6）和（7）聚焦透镜，（8） ）CCD摄像头<a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig2large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图3" class="xfigimg" src="/files/ftp_upload/55066/55066fig3.jpg" /> 图3 :设置图片 （ A ）真空设置的图片，包括微波涂抹器和光纤。 （ B ）光谱仪内部的图片，带有Littrow透镜和衍射光栅可见光<html>即（ C ）用于将强光照射到CCD摄像机的镜头系统的图像。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig3large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图4" class="xfigimg" src="/files/ftp_upload/55066/55066fig4.jpg" /> 图4 :作为压力函数的测量强度 测量的瑞利散射作为压力的函数，适用于不同的时间点。蓝色实线表示数据的线性拟合。误差条表示压力表的绝对误差。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig4large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 066 / 55066fig5.jpg"/&gt; 图5 :FTIR气体排气分析设计示意图 将气体放置在FTIR光谱仪的样品室中。电池与排气管串联连接，使气体流过。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig5large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图6" class="xfigimg" src="/files/ftp_upload/55066/55066fig6.jpg" /> 图6 : 原位 FTIR设置 原位 FTIR设置的原理图。流管是直立的，气体从底部流向顶部。管是FTIR光束的焦点。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig6large.jpg" target="_blank">请点击这里查看更大的经文</a>在这个数字上。 <img alt="图7" class="xfigimg" src="/files/ftp_upload/55066/55066fig7.jpg" /> 图7 : 原位 FTIR设置图 FTIR光谱仪样品室中波导的侧面（ A ）和顶部（ B ）视图。波导顶部的波纹管连接到真空泵，并充当反应器的排气口。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig7large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图8" class="xfigimg" src="/files/ftp_upload/55066/55066fig8.jpg" /> 图8 :代表能源效率和转换效率 在图（ A ）中，典型的等离子体被描绘为在127至279mbar的压力下应用的微波功率的函数。在图（ B ）中，描绘了转换效率。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig8large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图9" class="xfigimg" src="/files/ftp_upload/55066/55066fig9.jpg" /> 图9 :CO的代表性红外（IR）吸收光谱 图（ A ）表示气体排出物的红外吸收光谱（蓝点）。绿色实线表示数据的最小二乘法。拟合结果为T = 299.36 K，α= 14.7％。 （ B ）中显示放大图片。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig9large.jpg" target="_blank">请点击这里查看大图</a>r版本的这个数字。 <img alt="图10" class="xfigimg" src="/files/ftp_upload/55066/55066fig10.jpg" /> 图10 :测量的气体温度 在该图中，通过瑞利散射测量的等离子体中心的气体温度被显示为不同压力的能量输入的函数。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig10large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图11" class="xfigimg" src="/files/ftp_upload/55066/55066fig11.jpg" /> 图11 :等离子体放电的原位 IR吸收光谱 图（ A ）示出了测量的CO 2放电的IR吸收光谱。蓝线给了最适合的e数据（绿点），T = 700 K，T 12 = 1,250 K，T 3 = 1,500 K。红线给出拟合残差。 （ B ）中可以看到放大的图片。 <a href="//ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55066/55066fig11large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <table fo:keep-together.within-page="1"><tbody><tr><td></td><td> 电离 </td><td> 解离 </td></tr><tr><td></td><td>电子伏特</td><td>电子伏特</td></tr><tr><td> CO 2 </td><td> 13.77 </td><td> 5.52 </td></tr><tr><td> CO </td><td> 14.01 </td><td> 11.16 </td></tr><tr><td> O 2 </td><td> 12.07 </td><td> 5.17 </td></tr><tr><td> N 2 </td><td> 15.58 </td><td> 9.8 </td></tr><tr><td> CH 4 </td><td> 12.51 </td><td> 4.54 </td></tr><tr><td> CH 3 </td><td> 9.84 </td><td> 4.82 </td></tr><tr><td> CH 2 </td><td> 10.4 </td><td> 4.37 </td></tr><tr><td> CH </td><td> 10.64 </td><td> 3.51 </td></tr><tr><td> H 2 </td><td> 15.43 </td><td> 4.52 </td></tr></tbody></table> 表1: 常见物种和产物的电离和离解能。

Watch this Scientific Journal Video about Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry at JoVE.com

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

本文介绍了一种流动的微波反应器，用于驱动有效的非平衡化学，用于稳定分子如CO 2 ，N 2和CH 4的转化/活化。这里描述的程序的目标是测量原位气体温度和气体转化率。

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 ...

non-equilibrium-microwave-plasma-for-efficient-high-temperature

Universidad San Sebastian

Research

Education

JoVE Core

JoVE Journal

Mechanical Engineering

Chemistry

Unit 1

Virtual Work

SCIENTISTS IN ACTION

12.6K 次观看.  Dutch Institute for Fundamental Energy Research. 本文介绍了一种流动的微波反应器，用于驱动有效的非平衡化学，用于稳定分子如CO 2 ，N 2和CH 4的转化/活化。这里描述的程序的目标是测量原位气体温度和气体转化率。 

视频: Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes

Functionalized naphthalenes have applications in a variety of research fields ranging from the synthesis of natural or biologically active molecules to the preparation of new organic dyes. Although numerous strategies have been reported to access naphthalene scaffolds, many procedures still present limitations in terms of incorporating functionality, which in turn narrows the range of available substrates. The development of versatile methods for direct access to substituted naphthalenes is therefore highly desirable.
The Diels-Alder (DA) cycloaddition reaction is a powerful and attractive method for the formation of saturated and unsaturated ring systems from readily available starting materials. A new microwave-assisted intramolecular dehydrogenative DA reaction of styrenyl derivatives described herein generates a variety of functionalized cyclopenta[b]naphthalenes that could not be prepared using existing synthetic methods. When compared to conventional heating, microwave irradiation accelerates reaction rates, enhances yields, and limits the formation of undesired byproducts.
The utility of this protocol is further demonstrated by the conversion of a DA cycloadduct into a novel solvatochromic fluorescent dye via a Buchwald-Hartwig palladium-catalyzed cross-coupling reaction. Fluorescence spectroscopy, as an informative and sensitive analytical technique, plays a key role in research fields including environmental science, medicine, pharmacology, and cellular biology. Access to a variety of new organic fluorophores provided by the microwave-assisted dehydrogenative DA reaction allows for further advancement in these fields.

Microwave-assisted intramolecular dehydrogenative Diels-Alder (DA) reactions provide concise access to functionalized cyclopenta[b]naphthalene building blocks. The utility of this methodology is demonstrated by one-step conversion of the dehydrogenative DA cycloadducts into novel solvatochromic fluorescent dyes via Buchwald-Hartwig palladium-catalyzed cross-coupling reactions.

微波辅助分子内Diels-Alder反应的功能化萘/变色染料的合成脱氢

Functionalized naphthalenes have applications in a variety of research fields ranging from the synthesis of natural or biologically active molecules to ...

科研

化学

Preparation of Silica Nanoparticles Through Microwave-assisted Acid-catalysis

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan &#948; solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials&#39; morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by St&#246;ber&#39;s methods, which have smooth surfaces.

Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle ...

Quantitative Detection of Trace Explosive Vapors by Programmed Temperature Desorption Gas Chromatography-Electron Capture Detector

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive vapor samples. The direct liquid deposition method yields a higher fidelity between the analysis of vapor samples and the analysis of solution standards than using separate injection methods for vapors and solutions, i.e., samples collected on vapor collection tubes and standards prepared in solution vials. Additionally, the method can account for instrumentation losses, which makes it ideal for minimizing variability and quantitative trace chemical detection. Gas chromatography with an electron capture detector is an instrumentation configuration sensitive to nitro-energetics, such as TNT and RDX, due to their relatively high electron affinity. However, vapor quantitation of these compounds is difficult without viable vapor standards. Thus, we eliminate the requirement for vapor standards by combining the sensitivity of the instrumentation with a direct liquid deposition protocol to analyze trace explosive vapor samples.

Trace explosive vapors of TNT and RDX collected on sorbent-filled thermal desorption tubes were analyzed using a programmed temperature desorption system coupled to GC with an electron capture detector. The instrumental analysis is combined with direct liquid deposition method to reduce sample variability and account for instrumentation drift and losses.

定量检测痕量爆炸物蒸气通过程序升温脱附 - 气相色谱 - 电子捕获检测器

The direct liquid deposition of solution standards onto sorbent-filled thermal desorption tubes is used for the quantitative analysis of trace explosive ...

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 ...

环境科学

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 ...

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. ...

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

In recent years, non-thermal atmospheric pressure plasmas have been used extensively for surface treatments, in particular, due to their potential in biological applications. However, the scientific results often suffer from reproducibility problems due to unreliable plasma conditions as well as complex treatment procedures. To address this issue and provide a stable and reproducible plasma source, the COST-Jet reference source was developed.
In this work, we propose a detailed protocol to perform reliable and reproducible surface treatments using the COST reference microplasma jet (COST-Jet). Common issues and pitfalls are discussed, as well as the peculiarities of the COST-Jet compared to other devices and its advantageous remote character. A detailed description of both solid and liquid surface treatment is provided. The described methods are versatile and can be adapted for other types of atmospheric pressure plasma devices.

This protocol is presented to characterize the setup, handling, and application of the COST-Jet for the treatment of diverse surfaces such as solids and liquids.

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 ...

Building Langmuir Probes and Emissive Probes for Plasma Potential Measurements in Low Pressure, Low Temperature Plasmas

Langmuir probes have long been used in experimental plasma physics research as the primary diagnostic for particle fluxes (i.e., electron and ion fluxes) and their local spatial concentrations, for electron temperatures, and for electrostatic plasma potential measurements, since its invention by Langmuir in the early 1920s. Emissive probes are used for measuring plasma potentials. The protocols exhibited in this work serve to demonstrate how these probes may be built for use in a vacuum chamber in which a plasma discharge may be confined and sustained. This involves vacuum techniques for building what is essentially an electrical feedthrough, one that is rotatable and translatable. Certainly, complete Langmuir probe systems may be purchased, but they can also be built by the user at considerable cost savings, and at the same time be more directly adapted to their use in a particular experiment. We describe the use of Langmuir probes and emissive probes in mapping the electrostatic plasma potential from the body of the plasma up to the sheath region of a plasma boundary, which in these experiments&#160;is created by a negatively biased electrode immersed within the plasma, in order to compare the two diagnostic techniques and assess their relative advantages and weaknesses. Although Langmuir probes have the advantage of measuring the plasma density and electron temperature most accurately, emissive probes can measure electrostatic plasma potentials more accurately throughout the plasma, up to and including the sheath region.

The main goal of this work is to make it easier for research groups unfamiliar with Langmuir probes and emissive probes to use them as plasma diagnostics, especially near plasma boundaries. We do this by demonstrating how to build the probes from readily available materials and supplies.

构建朗缪尔探头和发射探头，用于低压、低温等离子体中的等离子体电位测量

Langmuir probes have long been used in experimental plasma physics research as the primary diagnostic for particle fluxes (i.e., electron and ion fluxes) ...

<meta charset="utf8"></head><body>用于多肽合成的多功能自制微波辅助系统

An Inexpensive Adaptation of a Commercial Microwave Reactor for Solid Phase Peptide Synthesis

A home-built apparatus to perform solid phase peptide synthesis (SPPS), assisted by microwave irradiation and heating, is presented. In contrast to conventional SPPS reaction vessels, which drain solvent and byproducts via a frit located at the bottom of the vessel, the presented apparatus employs a gas dispersion tube under vacuum to remove solvent, byproducts, and excess reagents. The same gas dispersion tube supplies nitrogen gas agitation of the SPPS beads during the reaction steps of coupling and deprotection. Microwave heating is beneficial for SPPS couplings of sterically hindered residues, such as alpha-aminoisobutyric acid (Aib), an alpha,alpha-dialkylated amino acid residue. This home-built apparatus has been used to prepare, via manual Fmoc SPPS methods, heptameric and octameric peptides dominated by the Aib residue, which is notoriously difficult to couple under standard room temperature conditions and reagents. Further, typical commercial microwave SPPS reactors are dedicated exclusively to SPPS synthesis rendering them inaccessible to non-SPPS users. In contrast, the presented apparatus preserves the versatility of the microwave reactor for conventional microwave acceleration of chemical reactions, as the apparatus is trivially removed from the commercial microwave reactor.

<meta charset="utf8"></head><body>用于固相肽合成的商用微波反应器的廉价改造

A simple, inexpensive, and novel apparatus for performing solid phase peptide syntheses in a commercial microwave reactor is presented.

用于固相肽合成的商用微波反应器的廉价改造

A home-built apparatus to perform solid phase peptide synthesis (SPPS), assisted by microwave irradiation and heating, is presented. In contrast to ...