The authors are grateful for the financial support given to this study by EU FP7 project ``Managing Risks of Nanomaterials`` (MARINA) (grant agreement no: 263215).

1.系统准备<ol><li>确保使用新的或很好地清洗粒子输运管道和接头装配该系统。确保室壁清洁和无颗粒（参照该清洁方法在协议结束时）。 </li><li>以除去潜在的背景颗粒，连接一个过滤干燥空气流（5-10升/分钟）直接到混合室（没有安装位置a和b之间的漏斗中图1），在至少30分钟。 </li><li>测量根据制造商的协议使用SMPS在测量室中的粒子个数浓度。如果浓度低于10＃/ cm 3的后三扫描，然后再考虑环境的清洁。请注意，使用的SMPS测量当流量可能会减缓。 </li><li>停止空气流，并在FIGUR用塑料或橡胶塞关闭取样管出口和出口管的出口（位置Cë1），以防止进入系统环境颗粒。 </li><li>准备和热身测量仪器（SMPS和OPC）和微粒采样器进行微观分析。 </li></ol> 2.材料准备<ol><li>存储测试材料相对于温度和湿度的良好控制的环境。这是确保在后续实验重复的结果非常重要。 </li><li>小心使用分析天平或高精度的平衡，在一个通风良好的空间称量粉末（ 例如 ，实验室罩）。 注: 二氧化钛，SiO 2的250-500毫克重量，ZnO和的CeO 2纳米粒子粉状体进行了测试，这些通常被证明为稳定雾化的至少30分钟是足够的。然而，适量的强烈依赖于粉末的类型，并且可以为散装材料，水泥或有机粉末显著变化。 </li><li>固定垂直气溶胶发生器LY，并从用适当清洁实验室漏斗气溶胶发生器的顶部开口进料粉末。在实验前，用清水冲洗漏斗和过滤的空气干燥，除去内壁上的灰尘沉积。轻轻敲击漏斗以确保所有的粉末颗粒被送入该过程。不以避免该材料的显著损失早期气雾硬摇动漏斗。 <ol><li>确保大多数粉粒到达发电机的底部，而不是落入周围倾斜壁上。轻轻敲击产生的侧壁移动敷粉末颗粒跌到了谷底。 </li><li>可替代地，使用长漏斗直接沉积在发电机底部的粉末颗粒。为安全起见，在一个通风橱或负压室内部进行这些操作。 </li></ol></li><li>如不粘材料可以滑动通过在底部的开口发电机，用直径2毫米的针在送粉前暂时封闭开口。 </li><li>取下漏斗，并关闭发生器的顶部和底部开口，以避免传输期间粒子发射。 </li></ol> 3.气雾<ol><li>安装气溶胶发生器，卸下入口和出口管连接到所述漏斗的块，其底部连接到过滤空气供应和其顶部的出口到混合室（分别为图1中的位置a和b），并与一垂直连接它金属支架。 </li><li>卸下设置退出（ 图1位置C）的块。 </li><li>交换机上的雾化流。使用流调谐器从0到0.3-0.5升/分钟慢慢提高速度。不移动到高流速过快-目的是要达到的流速可以为至少30分钟提供稳定的气溶胶生成。 <ol><li>为了实现这一目标，在此期间，稳定的雾化的不消耗显著粉末量。作为一个经验法则，使用约1厘米，用于产生一个强大的气雾流，同时维持稳定的浓度在相对 ​​长期间的流化床高度（用H在图1中表示）。如果进入雾化过程中的能量过强则材料将迅速用完，否则该实验的其余部分期间，以维持一个稳定的气溶胶生成。注意，流速范围可以针对不同的粉末变化;上述的值被用于测试上述纳米粉末。 </li></ol></li><li>交换机上的稀释气流。慢慢地从0到2升/分钟增加的速率。所需的总稀释流被采样设备来确定。开关电源，OPC和在这里介绍的系统中使用的微型采样要求的1.6-1.8升/分钟的总流量。 </li></ol> 4.表征<ol><li>启动在线测量仪器同时（这里，SMPS和OPC），一旦雾化和稀释流被引入。 注意:如果雾化的稳定状态下实现的，气溶胶粒子数浓度和大小分布应后约30分钟，成为稳定的。使用来自不同的条件（ 例如 ，湿度），并使用不同的粉末下气溶胶特性的比较这时间点开始测量。分析来自10个连续SMPS扫描结果来计算平均浓度和粒径分布。 </li><li>一旦雾化是稳定的，打开连接于TEM采样开始采样气载粒子的泵。使用通过涂覆有多孔碳膜的TEM网格的0.3升/分钟的流速。如果流速太高网格上的薄膜可能被损坏。对使用采样的详细信息，可21。通常情况下，在采样过程持续从头出3分。 <ol><li>根据不同的颗粒浓度变化的取样持续时间，并且通过粒子沉积（ 例如 ，50％）考虑TEM网格的一个适中的表面覆盖近似。厚厚的沉积可能会修改粒子形态，由于现场集聚。 </li></ol></li></ol> 5.后取样操作和清理<ol><li>在完成测量后，关闭稀释流，然后将雾化流。 </li><li>断开系统的气溶胶发生器，阻断其顶部和底部开口，并将其转移到清洁的空间。清洗在通风良好的清洗设备或一封闭空间，特别是如果危险材料已被处理。 </li><li>分散粉末残基与水或有机溶剂，这取决于粒子表面的亲水性。将溶液倾入关安全回收化学品的容器。长期实验，测试粉末往往STIC坚决ķ到玻璃墙，并且不容易溶解。如果发生这种情况，用酸或碱连同超声波清洗，以溶解粘材料。 </li><li>为了去除留在壁和彻底干燥发电机的内部的任何水分，穿过它的干燥空气为至少1小时。确保不存在明火或与有机溶剂工作时的火源，保证了空间良好的通风。 </li><li>断开粒子输运管道和连接器。与水或溶剂冲洗。擦拭的混合和测量室的内壁，用湿纸巾或布。干他们在一个开放的空间，至少一天或与下次试验之前1小时的干燥空气流。 </li><li>定期清洁SMPS冲击（如果使用）。 </li></ol>

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The authors declare that they have no competing financial interests.

基于漏斗气雾化的设置能有效激活在选定的能量输入级粉末颗粒（可通过空气流速雾化过程中量化）。粒子运动和碰撞在产生站点达到平衡状态，分手粉末附聚物并以恒定的速率发射相同尺寸分布的空气中的颗粒。一个稳定的雾化可以持续30分钟至至多2小时，这是足够的时间以高尺寸的分辨率，如SMPS甚至慢测量仪器，以产生统计学上显著的结果。设置只需要少量的测试材料，它可以是一个优点，用于测试贵重材料如纳米颗粒粉末。 然而，该系统的环境和工艺参数能显著影响试验结果。为了产生重复的数据，标准作业程序必须严格遵循整个experi求。在进行使用这个系统雾化测试中，以下几个方面应慎重考虑。 首先，为了获得有意义的结果，这是至关重要的设置的内部部件提供用于测试一个清洁的环境。污染物的潜在来源是环境颗粒和从以前的实验测试材料。环境粒子的影响通常消失比较快，一旦被引入雾化和稀释流。然而，从残留的材料干扰可以在整个实验持续。作为生成的气雾颗粒流动通过该系统，可以在输送管，弯曲点和连接器的窄的通道，并且该混合的内表面和测量室的内壁上沉积。如果这些部件不正常之前，新实验清洗，先前沉积的材料可以被不断地重新悬浮于主流气溶胶流的，从而干扰测试结果。 其次，粉末灌装过程应该非常仔细地进行。这里最显著的问题是供入设置的粉末的量，特别是当使用的材料的极少量。在给定的气雾流率，较少量的粉末的产生降低气溶胶浓度，并且可能具有较小尺寸的颗粒，由于每粉末的单位重量更高能量输入。此外，已经示出了测试材料（ 如 ，相对湿度和温度）的储存条件以影响粉末雾化行为和含尘22的水平。因此，原料粉末应始终保持在相同的大气条件下，在可能的情况。 第三，调整在实验开始时的气雾流大大影响检测结果。在流动急剧增加吹大的粉末颗粒ū峰值到空气和传播他们遍布漏斗状表面，显着降低了材料的可用于实验的其余部分的量。其后果可能是一个失败的测试，由于粉不足。 由于这里描述的设置不使用标准化的实验室设备，试图复制这一系统的核心部件时建，应从以下几个方面加以考虑。标准实验室分液漏斗可以用作气溶胶发生器（请注意，它们不应在加压条件下使用）。不同几何形状的分液​​漏斗中的实验进行了测试，并且它们的定制漏斗提供类似的功能。具有嵌入输送管的橡胶密封块可用作漏斗盖。 不同的几何形状，但类似的卷混合和测量室可以使用。请注意，车厢太大的将显著拖延时间NEEDED达到稳定的气溶胶条件（浓度）。所需的时间可以通过考虑的总空气流率和隔室的体积来估计。虽然该方法可以通过使用大量的稀释流被加速，应该记住的是，最终粒子个数浓度，可显着降低由于稀释，这可能会影响气溶胶的粒度分布，以及测量仪器的性能（取决于在他们的检测限）。电被推荐的导电材料。 运输管道的长度可以根据一般实验室设置而改变。然而，长度应，以便其在运输过程中，以避免显著粒子损失保持尽可能短。微粒穿透性效率可以通过考虑粒径，空气流速，管的直径和长度，并考虑两种重力沉积轴承或计算扩散损失，或两者。 不同的表征方法可以采用。然而，空气供应（稀释流）应调节以匹配总采样流速。不足的空气供应量将导致在测量室的负压，在室温粒子从而导致在结论中的错误绘图。不同的空气供应源可以使用，但确保它们无颗粒或预治疗与高效率过滤器的空气。 这种雾化方法的一个主要的限制是，它需要的测试粉末的良好的流动性，以便在相对长的时期内保持稳定的颗粒的产生。粘的材料，如具有高水分含量的亲水性粉末，通常停止在雾化过程的早期阶段中流动，并产生非常低的粒子浓度。解决这一问题的可能方式可以包括一个预处理原料粉末，如烘干-S的O作为改善其流动性。用途后的原料的贮存条件应保持良好， 例如 ，保持在干燥的环境中和适当的温度下。在实验中，更高的气雾流动速度（0.5-1升/分钟）和较大量的原材料（ 例如 ，500毫克）的可使用。此外，降低了稀释流量可以增加在测量室的颗粒浓度。 这种方法的另一个限制是尘埃粒子的生成速率（因此粒子个数浓度在测量室）的可重复性。变化一定程度依然存在。改进的可能途径是更好的界定喂养过程中减少材料损耗，并控制良好的气雾流量。 该系统和这里描述的方案可用于各种应用。使用相对少量的试料，使潜在诉方法aluable作为测试含尘粉的替代工具。由我们的系统的一些常见的材料产生的空气中的颗粒的水平的排名是类似于在现有雾化系统19，旋转鼓15,17，连续滴23和涡旋振荡器的方法24，如观察到的。此外，可调节的能量输入（空气流量），也可以用于研究纳米粒子粉末附聚物的稳定性。最后，稳定气溶胶的产生可以作为在体内或体外毒理学研究空降工程纳米颗粒的可靠来源。可控粒子浓度将允许的剂量依赖的生物反应的分析。相比，使用液体悬浮其他雾化方法，该方法避免了诸如材料悬浮性和悬浮颗粒的物理-化学性质修饰（潜在的问题例如 ，一个gglomeration，表面特性）。

纳米材料的粉末被广泛用于不同的工业部门，作为用于生产新产品，或作为添加剂用于他们的功能性应用1-4的原料。然而，对于工人暴露于纳米粉末气溶胶的潜力已在各种职业搬运活动5-8所指出的，并且在体内 和体外毒理学研究9-12相关联的健康风险已研究英寸为了方便有效的发展战略，以保护处理纳米材料的工人，职业卫生专业人员需要更好地了解纳米颗粒气溶胶如何从受到外部能源投入粉状物料产生的。 不同实验室系统已被开发，以模拟在实际条件粉末雾化行为。其中，两个标准程序建立的参考方法<su用于测试粉末含尘，其被定义为粉末的趋势，进行给定的能量输入，对&gt; 13释放空气中的颗粒。第一种方法使用一个旋转鼓，作为能量输入的介质和粉末颗粒14,15的雾化。第二种方法通过一个垂直圆柱体滴以恒定速率的粉末和通过的上升空气流16的装置aerosolizes粉末颗粒。然而，这些方法需要相对大量的试验材料（35 毫升或500克），并且这可以是由于它们的高成本和潜在的暴露风险与纳米材料的粉末的问题。按比例缩小的测试系统相结合的单点和转鼓工艺的开发，允许使用少量的试验粉末（6克样品）17。基于涡流激振器最近开发的雾化系统也被用于纳米粉体，使测试向下原材料1厘米3 <suP&gt; 18。 在这里，我们提出了基于实验室纳米粉体漏斗测试一种新型的气雾化和去聚集系统。它提供了使用小于1g试验粉末的稳定气溶胶生成过程。稳定雾化可维持足够长的持续时间为强大的气溶胶特征。系统的性能进行了详细两个以前的出版物19,20进行了描述。 测试设置由气雾剂发生器，混合和计量室，和表征仪器， 如图1。粒子输送管道和连接器的连接这些不同的元件。的流调谐器和两个流量计控制和监视系统中的空气流的条件。压力计和一个温度和湿度的传感器监测测量室内部的环境。干燥的压缩空气是使用hyperfilter在进入系统之前过滤。一个细长的V形，玻璃气雾剂发生器用于粉末雾化。这种几何形状便于健壮雾化过程和光滑颗粒输送到随后的隔室。在漏斗的底部的流动状态是湍流由于与粉末颗粒的交互作用，而它是层中的上部（重新编号&lt;15）。发电机壁的厚度是专门设计用来抵御需要使用临界孔解凝集试验的高压（高达400千帕△P）。一个高精度流量控制调谐器在0.01升/分钟为单位的流量。导电管（6外径，厚度为1毫米）被用来避免由于在运输过程中的静电沉积粒子的损失。管长是气溶胶发生器和混合室，20厘米混合室和测量室之间，和100厘米为取样管之间约50cm。向1L的金属瓶被用作混合湛误码率，和一个12升的金属鼓被用作测量室。颗粒样品从测量室的顶部绘制。一个出口引导额外流入过滤系统。混合和测量室电接地，以防止颗粒的静电损耗。测量仪器包括一个扫描移动粒度仪（SMPS）和颗粒数浓度和粒度分布的光学粒子计数器（OPC），以及用于颗粒形态分析的透射电子显微镜（TEM）采样器（MPS）。 安装的雾化过程类似于流化床工艺。空气流从底部开口成漏斗（2毫米直径）进入并aerosolizes的粉末。粉末颗粒以类似的方式移动到水在一个喷泉。生成的气雾剂满足在混合腔室中的稀释液的流动。稀释空气流量可被调节为，如果效果不同水平的湿度的此参数的需要的分析。腔室的空气兼作缓冲容积根据采样需要用干燥稀释空气平滑地混合所述气雾剂。气溶胶流然后经由正常管出口（用于气雾化测试）或临界孔（为解凝聚测试）引入到测量室。孔可以提供不同的压力降的条件下，施加剪切力，以通过它的颗粒。这种机制允许其解聚势（机械稳定性）的研究。 <img alt="图1" src="/files/ftp_upload/54414/54414fig1.jpg" /> 图1.雾化和解聚体系的示意图。缺省情况下，一个管连接与所述测量室中的混合室中。中所示的小孔是一个可选的附加 ​​（在本协议中没有说明）。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig1large.jpg" target="_blank">请点击此处Ť</a>Ø查看此图的放大版本。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>titanium dioxide nanopowder</td>
			<td>JRC</td>
			<td>NM-103/104</td>
			<td>Reference materials provided within EU FP7 MARINA project</td>
		</tr>
		<tr>
			<td>silicon dioxide nanopowder</td>
			<td>AEROSIL</td>
			<td>R974</td>
			<td></td>
		</tr>
		<tr>
			<td>silicon dioxide nanopowder</td>
			<td>JRC</td>
			<td>NM-200</td>
			<td>Reference materials provided within EU FP7 MARINA project</td>
		</tr>
		<tr>
			<td>zinc oxide nanopowder</td>
			<td>JRC</td>
			<td>NM-110/111</td>
			<td>Reference materials provided within EU FP7 MARINA project</td>
		</tr>
		<tr>
			<td>cerium dioxide nanopowder</td>
			<td>JRC</td>
			<td>NM-211/212</td>
			<td>Reference materials provided within EU FP7 MARINA project</td>
		</tr>
		<tr>
			<td>The V-shaped aerosol generator</td>
			<td>Souffleur de verre S.A.</td>
			<td></td>
			<td>Specially made based on conditions required in the experiments (e.g., geometry, thickness)</td>
		</tr>
		<tr>
			<td>scanning mobility particler sizer (SMPS)</td>
			<td>GRIMM</td>
			<td>Model N&#176; 5.403</td>
			<td>Size range: 11.1&#8211;1083.3 nm (impactor: d50=1082 nm); composed of a condensation particle counter (CPC) and a dynamic mobility analyzer (DMA); sampling flow ate: 0.3 L/min; sheath flow rate: 3.0 L/min; with standard multiple charge correction and diffusion loss correction;&#160;</td>
		</tr>
		<tr>
			<td>optical particle counter (OPC)</td>
			<td>GRIMM</td>
			<td>Model N&#176; 5.403</td>
			<td>Size range: 0.25-32 &#181;m</td>
		</tr>
		<tr>
			<td>mini-particle sampler (MPS)</td>
			<td>ECOMESURE</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>transport tubes</td>
			<td>Milian S.A.</td>
			<td>8 mm-conductive</td>
			<td>6 mm inner diameter</td>
		</tr>
	</tbody>
</table>

a system to create stable nanoparticle aerosols from nanopowders

Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment.

图2示出的随时间的总气溶胶粒子数浓度和大小的变化，使用上述的协议中的雾化实验疏水SiO 2的一个典型的例子。颗粒浓度开始就引入了雾化气流上升。颗粒的几何平均大小逐渐增加了。后大约10 SMPS扫描（3.5分钟/扫描），气溶胶开始进入稳定状态，其中，颗粒浓度和平均直径不再由任何显著量变化。这种状态持续了30分钟以上，这是足以完成10个3分钟的SMPS扫描。 图3示出了在个人尺寸分布的形式在粒子浓度的变化（基于相同的数据在图2中）。高峰缓慢上升一段时间，并且一旦该气溶胶变得稳定，它仍然在整个第相同尺寸范围内测试电子休息。 在实验开始时示出的非常小的平均直径是不是由于不稳定粉末雾化。相反，它是通过将粉末填充过程之后漏斗内的残留周围空气造成的。空气的这种体积是第一流入测量室，并在它的初始扫描（ 图4）是由SMPS采样。这可以通过，如果这是需要通过手边的科学问题在一个干净的房间进行所有的实验来避免。事实上，在第一次扫描的尺寸分布非常类似于环境空气。作为粉末气雾颗粒继续从迅速减少环境粒子流中的干扰，以及之后的效果几SMPS扫描几乎已经消失。 <img alt="图2" src="/files/ftp_upload/54414/54414fig2.jpg" /> 图2. 更改总粒子数浓度和平均气雾实验直径（241毫克疏水的SiO 2;气雾流量0.3升/分钟）。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54414/54414fig3.jpg" /> 图3. 在气雾实验粒度分布变化。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54414/54414fig4.jpg" /> 图4. 气雾剂的粒度分布在雾化试验开始。粒子浓度上呈现的相对比例（归一吨Ø为了频谱从一个非常低的浓度后浓度较高的扫描，光谱扫描先比较总人数）。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 在颗粒浓度的变化并不总是遵循同样的模式。四种可能性通常可以在雾化测试可以看出。在图5A中 ，浓度缓慢升 ​​至一个"高原"区域，则仍然是实验的其余部分几乎不变。在图5B中 ，浓度先上升至最高点，逐渐下降到一个较低的水平，然后超过1.5小时保持稳定。在图5C中 ，浓度继续降低到零。在图5D中 ，浓度增加至最大值，仍然保持，ð有一段时间，然后再次下降。 当标准操作程序之后方案（一）通常看到。雾化气流慢慢引入和最后的适当的范围内稳定。原料的量足以相对于所述雾化水平，并以恒定的气溶胶发生速率可维持相当长的时间周期。方案（b）是最有可能是由于在整个实验过大的雾化流，与粉末的数量不足组合。粉末被迅速消耗，不能够维持稳定的悬浮微粒产生。方案（c）示出在粒子个数浓度，只是一个很短的时间后，空气流速被重新调整到一个适当的范围内，并在整个试验的其余保持恒定的类似下降到场景（b）中。这使粒子浓度逐渐达到一个稳定范围内。方案（D）一当使用原料的量不足ppears。在实验的后期阶段，不再有足够的测试粉末以恒定的速率来产生气溶胶粒子，如在雾化的早期阶段是可能的。因此，在系统中的微粒浓度降低。 <img alt="图5" src="/files/ftp_upload/54414/54414fig5.jpg" /> 图 5. 在气雾实验改变总颗粒物浓度典型模式:（A）慢慢增加，直至达到一个平台; （B）逐渐减小至零; （ 三 ）迅速达到高峰，然后下降到一个稳定的水平; （ 四 ）提高到一个稳定的状态，并保持一定的时间周期，然后下降。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> </p&gt; 不同的雾化流速，以研究其对气溶胶的产生的影响进行了测试。从0.3-1.1，流量率/分钟被使用，并且将所得的粒径分布如图6所示。在光谱的峰上升作为流增加。在最高流速（1.1升/分钟），微米级的空气中的颗粒开始进入系统（二次峰）。气溶胶粒子的模态尺寸停留相似时相同的雾化气流下，但是，它们逐渐降低时的空气流通过的范围内增加从0.3-0.7升/分钟（ 图7）。日益增加的颗粒产生速率及减少平均粒径为流速增加表明更为动态雾化处理（与显著粒子运动和碰撞）促进粉末颗粒的解聚，从而导致该气溶胶的变形大小分布产生的颗粒。 <img alt="图6" src="/files/ftp_upload/54414/54414fig6.jpg" /> 图6. 改变粒度分布随空气流量（0.3〜1.1 L /分钟）。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图7" src="/files/ftp_upload/54414/54414fig7.jpg" /> 图7. 在不同的流量粒度分布的比较。光谱变成了相对规模相似的高度（归总粒子数），它具有更好的高峰期转变。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig7large.jpg" target="_blank">请点击此处查看这个大版本数字。</a> 图8示出了从使用相同的材料四个重复试验中的粒度分布的变化的一个例子。标准偏差为总颗粒浓度为39.7％，为几何平均大小为6.6％。数量浓度的变化可能是由于以下几个原因:1）的不同的原料的状态（ 例如 ，附聚水平）; 2）在灌粉过程中的人为因素（影响沉积在漏斗底部的粉量，从而可用于气雾化的量）;或3）在雾化的开始空气流量调节。 <img alt="图8" src="/files/ftp_upload/54414/54414fig8.jpg" /> <strong&gt;的图8. 变异的重复实验雾化测试结果的疏水性二氧化硅 。误差条表示在个体大小渠道粒子数浓度的标准偏差。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/54414/54414fig8large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about A System to Create Stable Nanoparticle Aerosols from Nanopowders at JoVE.com

A System to Create Stable Nanoparticle Aerosols from Nanopowders

We designed and developed an effective nanopowder aerosolization setup and operating protocol. The system generated nanoparticle aerosols with stable number concentrations and size distributions for long durations, requiring only small quantities of test material (min. 200 mg).

系统创建从纳米粉体纳米稳定气溶胶

Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring ...

a-system-to-create-stable-nanoparticle-aerosols-from-nanopowders

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

9.5K 次观看.  Universities of Lausanne and Geneva. We designed and developed an effective nanopowder aerosolization setup and operating protocol. The system generated nanoparticle aerosols with stable number concentrations and size distributions for long durations, requiring only small quantities of test material (min. 200 mg). 

视频: A System to Create Stable Nanoparticle Aerosols from Nanopowders

Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents and hence higher efficiencies. Photon up-conversion by way of triplet-triplet annihilation (TTA-UC) is an attractive technique for using these otherwise wasted low energy photons to produce photocurrent, while not interfering with the photoanodic performance in a deleterious manner. Further to this, TTA-UC has a number of features, distinct from other reported photon up-conversion technologies, which renders it particularly suitable for coupling with DSC technology. In this work, a proven high performance TTA-UC system, comprising a palladium porphyrin sensitizer and rubrene emitter, is combined with a high performance DSC (utilizing the organic dye D149) in an integrated device. The device shows an enhanced response to sub-bandgap light over the absorption range of the TTA-UC sub-unit resulting in the highest figure of merit for up-conversion assisted DSC performance to date.

An integrated device, incorporating a dye-sensitized solar cell and triplet-triplet annihilation up-conversion unit was produced, affording enhanced light harvesting, from a wider section of the solar spectrum. Under modest irradiation levels a significantly enhanced response to low energy photons was demonstrated, yielding a record figure of merit for dye-sensitized solar cells.

集成的三重态 - 三重态湮灭上转换系统，提高染料敏化太阳能电池的响应子带隙光

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents ...

科研

工程学

A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space

A simple Positron Emission Tomography (PET) prototype has been constructed to fully characterize its basic working principles. The PET prototype was created by coupling plastic scintillator crystals to photomultipliers or PMT&#39;s which are placed at opposing positions to detect two gamma rays emitted from a radioactive source, of which is placed in the geometric center of the PET set-up. The prototype consists of four detectors placed geometrically in a 20 cm diameter circle, and a radioactive source in the center. By moving the radioactive source centimeters from the center the system one is able to detect the displacement by measuring the time of flight difference between any two PMT&#39;s and, with this information, the system can calculate the virtual position in a graphical interface. In this way, the prototype reproduces the main principles of a PET system. It is capable to determine the real position of the source with intervals of 4 cm in 2 lines of detection taking less than 2 min.

We present a simple but well-constructed Positron Emission Tomography (PET) system and elucidate its basic working principles. The goal of this protocol is to guide the user in constructing and testing a simple PET system.

一个基本的正电子发射断层扫描系统构建以定位放射源的双维空间

A simple Positron Emission Tomography (PET) prototype has been constructed to fully characterize its basic working principles. The PET prototype was ...

Visible-light Induced Reduction of Graphene Oxide Using Plasmonic Nanoparticle

Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using visible light irradiation with plasmonic nanoparticles. The plasmonic nanoparticle is used to improve the reduction efficiency of GO. It only takes 30 min&#160;at RT by illuminating the solutions with Xe-lamp, the r-GO solutions can be obtained by completely removing gold nanoparticles through simple centrifugation step. The spherical gold nanoparticles (AuNPs) as compared to the other nanostructures is the most suitable plasmonic nanostructure for r-GO preparation. The reduced graphene oxide prepared using visible light and AuNPs was equally qualitative as chemically reduced graphene oxide, which was supported by various analytical techniques such as UV-Vis spectroscopy, Raman spectroscopy, powder XRD and XPS. The reduced graphene oxide prepared with visible light shows excellent quenching properties over the fluorescent molecules modified on ssDNA and excellent fluorescence recovery for target DNA detection. The r-GO prepared by recycled AuNPs is found to be of same quality with that of chemically reduced r-GO. The use of visible light with plasmonic nanoparticle demonstrates the good alternative method for r-GO synthesis.

A simple protocol for the preparation of reduced graphene oxide using visible light and plasmonic nanoparticle is described.

可见光诱导的还原氧化石墨烯的使用电浆纳米粒子

Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using ...

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently. 
Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches. 
In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies.

Saturable and reverse saturable scattering were discovered in isolated plasmonic particles and adopted as a novel non-bleaching contrast method in super-resolution microscopy. Here the experimental procedures of detecting and extracting nonlinear scattering are explained in detail, as well as how to enhance resolution with the aid of saturated excitation microscopy.

从单电浆纳米粒子散射非线性测量

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

纳米粒子 - 聚合物复合材料使用直接荧光成像的先进成分分析

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

The Evolution of Silica Nanoparticle-polyester Coatings on Surfaces Exposed to Sunlight

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings. No significant change in surface micro-topography was detected using optical profilometry, however, statistically significant nanoscale changes to the surface were detected using atomic force microscopy. Analysis of the X-ray photoelectron spectroscopy and attenuated total reflection infrared micro-spectroscopy data revealed that degradation of the ester groups had occurred through exposure to ultraviolet light to form COO&#903;, -H2C&#903;, -O&#903;, -CO&#903; radicals. During the degradation process, CO and CO2 were also produced.

Two types of surfaces, polyester-coated steel and polyester coated with a layer of silica nanoparticles, were studied. Both surfaces were exposed to sunlight, which was found to cause substantial changes in the chemistry and nanoscale topography of the surface.

表面上的纳米硅聚酯涂料暴露在阳光下的演变

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, ...

Testing of Nanoparticle Release from a Composite Containing Nanomaterial Using a Chamber System

With the rapid development of nanotechnology as one of the most important technologies in the 21st century, interest in the safety of consumer products containing nanomaterials is also increasing. Evaluating the nanomaterial release from products containing nanomaterials is a crucial step in assessing the safety of these products, and has resulted in several international efforts to develop consistent and reliable technologies for standardizing the evaluation of nanomaterial release. In this study, the release of nanomaterials from products containing nanomaterials is evaluated using a chamber system that includes a condensation particle counter, optical particle counter, and sampling ports to collect filter samples for electron microscopy analysis. The proposed chamber system is tested using an abrasor and disc-type nanocomposite material specimens to determine whether the nanomaterial release is repeatable and consistent within an acceptable range. The test results indicate that the total number of particles in each test is within 20% from the average after several trials. The release trends are similar and they show very good repeatability. Therefore, the proposed chamber system can be effectively used for nanomaterial release testing of products containing nanomaterials.

Nanoparticle release is tested using a chamber system that includes a condensation particle counter, an optical particle counter and sampling ports to collect filter samples for microscopy analysis. The proposed chamber system can be effectively used for nanomaterial release testing with a repeatable and consistent data range.

从使用室系统一个复合含纳米材料的纳米颗粒释放测试

With the rapid development of nanotechnology as one of the most important technologies in the 21st century, interest in the safety of consumer products ...

Fabrication of White Light-emitting Electrochemical Cells with Stable Emission from Exciplexes

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active layer which consists of blue-fluorescent poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and &#960;-conjugated triphenylamine molecules. This white light emission originates from exciplexes formed between PFD and amines in electronically excited states. A device containing PFD, 4,4&#39;,4&#39;&#39;-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), Poly(ethylene oxide) and K2CF3SO3 showed white light emission with Commission internationale de l&#39;&#233;clairage (CIE) coordinates of (0.33, 0.43) and a Color Rendering Index (CRI) of Ra = 73 at an applied voltage of 3.5 V. Constant voltage measurements showed that the CIE coordinates of (0.27, 0.37), Ra of 67, and the emission color observed immediately after application of a voltage of 5 V were nearly unchanged and stable after 300 sec.

The authors present a method for fabricating stable white-light-emitting electrochemical cells utilizing emission from exciplexes formed between a blue-emitting fluorene polymer and aromatic amines.

白的制造发光电化学细胞与来自激发络合物稳定的发射

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active ...

Uncoupling Coriolis Force and Rotating Buoyancy Effects on Full-Field Heat Transfer Properties of a Rotating Channel

An experimental method for exploring the heat transfer characteristics of an axially rotating channel is proposed. The governing flow parameters that characterize the transport phenomena in a rotating channel are identified via the parametric analysis of the momentum and energy equations referring to a rotating frame of reference. Based on these dimensionless flow equations, an experimental strategy that links the design of the test module, the experimental program and the data analysis is formulated with the attempt to reveal the isolated Coriolis-force and buoyancy effects on heat transfer performances. The effects of Coriolis force and rotating buoyancy are illustrated using the selective results measured from rotating channels with various geometries. While the Coriolis-force and rotating-buoyancy impacts share several common features among the various rotating channels, the unique heat transfer signatures are found in association with the flow direction, the channel shape and the arrangement of heat transfer enhancement devices. Regardless of the flow configurations of the rotating channels, the presented experimental method enables the development of physically consistent heat transfer correlations that permit the evaluation of isolated and interdependent Coriolis-force and rotating-buoyancy effects on the heat transfer properties of rotating channels.

Here, we present an experimental method for decoupling the interdependent Coriolis-force and rotating-buoyancy effects on full-field heat transfer distributions of a rotating channel.

解耦科里奥利力和旋转浮力对旋转通道全场传热性能的影响

An experimental method for exploring the heat transfer characteristics of an axially rotating channel is proposed. The governing flow parameters that ...

A Rapid Method for Modeling a Variable Cycle Engine

The variable cycle engines (VCE) that combine the advantages of turbofan and turbojet engines, are widely considered to be the next generation aircraft engines. However, developing VCE requires high costs. Thus, it is essential to build a mathematical model when developing an aircraft engine, which may avoid a large number of real tests and reduce the cost dramatically. Modeling is also crucial in control law development. In this article, based on a graphical simulation environment, a rapid method for modeling a double bypass variable cycle engine using object-oriented modeling technology and modular hierarchical architecture is described. Firstly, the mathematical model of each component is built based on the thermodynamic calculation. Then, a hierarchical engine model is built via the combination of each component mathematical model and the N-R solver module. Finally, the static and dynamic simulations are carried out in the model and the simulation results prove the effectiveness of the modeling method. The VCE model built through this method has the advantages of clear structure and real-time observation.

Here, we present a protocol to build a component-level mathematical model for a variable cycle engine.

可变循环引擎建模的快速方法

The variable cycle engines (VCE) that combine the advantages of turbofan and turbojet engines, are widely considered to be the next generation aircraft ...