1。系统配置<ol><li>架F-7000荧光光谱仪配备高感光度扩展范围的R-928F探测器的光电倍增管。 </li><li>使用的F-7000附件:罗丹明B，光扩散，红色过滤器和不合标准的光源产生的光谱仪器的校正因子。 </li><li>量子产量测量附件，其中包括:60毫米，积分球，三氧化二铝白色的瓷砖，白色标准Spectralon粉细胞（2EA），氧化铝粉和量子产率的软件。 </li><li>报告生成程序和相应的模板将用于色度坐标计算。 </li></ol> 2。系统设置<ol><li>打开日立F-7000荧光光谱仪，使氙灯预热一小时。开始使用安装在仪器的标准样品室（试管架）。 </li></ol> 3。 ACQuisition的积分球校正因子测量积分球的校正因子时，软件会自动选择表1中列出的参数测量试验。 <table border="1"><tbody><tr><td colspan="2"> 分析条件 </td></tr><tr><td>测量</td><td>波长扫描</td></tr><tr><td>扫描模式</td><td>同步</td></tr><tr><td>数据模式</td><td>荧光</td></tr><tr><td>电磁轮候册</td><td> 200纳米</td></tr><tr><td> EX开始轮候册</td><td> 200纳米</td></tr><tr><td> EX完轮候册</td><td> 900毫微米</td></tr><tr><td>扫描速度</td><td> 240纳米/分钟</td></tr><tr><td>延迟</td><td> 5.0小号</td></tr><tr><td> EX狭缝</td><td> 5.0纳米</td></tr><tr><td>电磁缝</td><td> 20纳米</td></tr><tr><td> PMT电压</td><td> 250伏</td></tr><tr><td>纠正谱</td><td>作者: </td></tr><tr><td>响应</td><td>汽车</td></tr></tbody></table> 表1。 3.1。收购漫射数据<ol><li>放置在标准的样品室的扩散，并关闭样品室。 </li><li>点击窗口上的量子产率修正系数的测量，然后在扩压测量。 </li><li>输入文件名 ​​:"IS_factor_F70_diffuser"扩散数据，并单击"确定"（ 视频1）。 </li><li>经过测量，该文件将被保存在"正确"的佛罗里达州解决方案的文件夹， 图1是一个扩散器测量数据的例子。 </li></ol> 3.2。没有样品采集校正系数（参考） &lt;OL&gt; <li>从仪器上取下，商店扩散标准​​的样品室，然后安装在积分球。 </li><li>充满了高度至少25毫米，以确保粉末充分涵盖了积分球端口的氧化铝粉粉末细胞。点击底部的细胞仔细压缩粉末。 </li><li>参考端口（P2）的积分球（一个面临排放单色）和氧化铝采样口（P1）的积分球（粉细胞放置在白色瓷砖的三氧化二铝面临的激励单色）。 </li><li>量子产率修正系数的测量窗口上点击，然后在积分球测量（不含样品）（ 视频2）。 </li><li>该软件会提​​醒你设置的样本。输入" 是没有样本 "的名称，并单击"确定"。 </li><li>经过测量，该文件将被保存在文件夹"校正<html> T"FL的解决方案。 图2是一个没有样品的测量数据的积分球的例子。 </li></ol> 3.3。采集样品存在校正因子: <ol><li>与三氧化二铝粉末的细胞取出，并更换它与Spectralon白色标准。 （Spectralon标准应该是面对激发单色器（P1））。 </li><li>量子产率修正系数的测量窗口上点击，然后在积分球测量（样品）。该软件会提​​醒你设定的标准测量反射材料。 </li><li>输入名称:"与样本 "积分球与样本数据文件，并单击OK（ 视频3）。 </li><li>经过测量，该文件将被保存在"正确"的佛罗里达州解决方案的文件夹。 图3是一个与测量数据样本的积分球的例子。 </li></ol>"&gt; 注:如果您需要使用截止过滤器来阻止二阶散射光的干扰荧光峰的发射端，您将需要使用的扩散和扩散，并适当的过滤器测量基准这些。数据文件将被使用的软件时，量子产率计算，在实践中，我们建议所有的系统设置的初始部分的截止过滤器测量。 4。样品测​​量（水杨酸钠粉） 量子产率的测量涉及收购都没有样本（参考），并在样品存在的发射光谱。选择分析测量参数如下: <ol><li>点击"方法"按钮，在常规选项卡选择波长扫描测量模式，并输入适当的信息运营商及配件（ 视频4）。 </li><li>点击"工具"选项卡，并输入仪器的测量参数，如表2（视频5）所示。 </li></ol><table border="1"><tbody><tr><td colspan="2"> 分析条件 </td></tr><tr><td>测量</td><td>波长扫描</td></tr><tr><td>扫描模式</td><td>排放</td></tr><tr><td>数据模式</td><td>荧光</td></tr><tr><td> EX轮候册</td><td> 350纳米</td></tr><tr><td>新兴市场开始轮候册</td><td> 330 nm处</td></tr><tr><td>电磁结束轮候册</td><td> 600纳米</td></tr><tr><td>扫描速度</td><td> 1200纳米/分钟</td></tr><tr><td>延迟</td><td> 0秒</td></tr><tr><td> EX狭缝</td><td> 5.0纳米</td></tr><tr><td>电磁缝</td><td> 5.0纳米</td></tr><tr><td> PMT电压</td><td>为350 V </td></tr><tr><td>纠正谱</td><td>作者: </td></tr><tr><td>响应</td><td>汽车</td></tr><tr><td>纠正谱</td><td>作者: </td></tr></tbody></table> 表2。 <ol start="3"><li>不需要额外的设置都需要在这个时候，因为已测数据后，可监控，处理和报告"选项卡设置。我们只是对其进行审查，然后点击"确定"按钮，以设置在仪器（ 视频6）选定的测量参数。 </li><li>作为一个选项，选择设置可以保存供将来使用。我们现在将着手测量氧化铝的参考标准，采用直接激发。 </li><li>将粉细胞样本中测量端口（P1）（在前面的激发光束）与氧化铝粉。 </li><li>点击"示例"按钮键入样品名称:"P1_Baseline_Al2O3"，然后点击"自动文件"旁边的框。选择的数据文件夹和文件的名称:"P1_Baseline_Al2O3"，然后单击"保存"和"确定"（ 视频）。 </li><li> "办法"按钮上点击Al2O3样品的测量。 （ 视频8），数据处理窗口打开后，点击"自动刻度轴"按钮，调整规模，以可视化的直接激发（ 图4）散射峰。 </li><li>现在，我们将继续使用直接激发水杨酸钠测量样品。点击"样品"图标，进入" 水杨酸P1_Sodium"的样品和文件名 ​​，然后单击OK按钮（ 视频9）。 </li><li>放置在粉细胞，并在积分球（港口面临的激发光束）的P1口水杨酸钠样品，并点击"测量"按钮。 （ 视频10）当数据的过程ING窗口打开后，点击"自动刻度轴"按钮，调整规模和可视化的散射和荧光峰。 </li><li>在这个时候，我们将重复使用的样品放置在积分球的P2口为三氧化二铝和水杨酸钠的测量，为了阅读使用间接激励。 </li><li>首先点击"样本"按钮和类型的样品和文件名​​:"P2_Baseline_Al2O3"（视频11）。 </li><li>将氧化铝白色瓷砖从P2 P1的积分球，放在一个细胞充满P2中铝氧化物粉末。 </li><li> "办法"按钮，点击读取样本（ 视频12）。 </li><li>完成样品的测量，我们需要衡量水杨酸钠样品使用间接照射。首先，我们在前面的步骤中键入样品和文件名。该名称将成为P2_Sodium水杨酸 （ 视频13）。 </li><li>水杨酸钠样品放置在积分球的P2口，然后按一下测量按钮（ 视频14）。 </li></ol> 5。量子产率计算首先，我们将继续装载积分球的校正因子。 <ol><li>量子产率计算按钮，点击打开的量子产率的计算程序（ 视频15）。 </li><li>点击量子产率修正系数的设置按钮（ 视频16）。 </li><li>点击积分球校正选项卡，点击"积分球校正"前的复选框，然后在过滤器校正"选项卡，确保未选中"过滤器校正"框中，单击"再次在积分球更正"选项卡（ 视频17 ）。 </li><li>漫反射测量数据部分点击Load按钮，然后选择"文件"IS_factor_F70样本 "（ <stronG&gt;视频18）。 </li><li>选择"IS_factor_F70_diffuser"的文件，然后点击Load按钮（ 视频19）。 </li><li>点击的积分球测量数据的Load按钮（样本）一节（ 视频20）。 </li><li>选择"IS_factor_F70没有样品 "文件，然后点击Load按钮（ 视频21）。 </li><li>点击Load按钮的积分球测量数据（样本）一节（ 视频22）。 </li><li>选择" 样IS_factor_F70"的文件，然后负载按钮（ 视频23）。 </li><li>归波长可以留在600nm的波长值等于1积分球校正或调整。要做到这一点，确保在"显示量子产率计算窗口"前面的复选框被选中，并单击"确定"按钮的"量子产量因子设置"windoW，这将关闭此窗口（ 视频24）。 </li><li>现在的"量子产量计算"窗口"积分球更正"选项卡上单击调整光标，直到积分球校正读为"1"，使波长（ 视频25）。 </li><li>点击" 量子产率修正系数的设定 "，如果需要改变波长归在上一步得到的读数，然后单击"确定"按钮（ 视频26）。 </li></ol>下一步是要加载的基线和样本数据文件<ol start="13"><li>点击"量子产率的计算"选项卡（ 视频27）。 </li><li>加载"数据无样品直接照射（ 文件P1_Baseline_氧化铝 ），点击直接照射（ 视频28）负载按钮和负载"样本数据"（ 文件P1_Sodium水杨酸 ）。 </li><li&gt;"下一步，我们将继续选择"散射"和"荧光"地区（ 视频29）。 </li><li>现在，我们将计算出样品直接照射的量子产率。点击"计算"按钮，并宣读结果（ 视频30）。最后考虑到间接激发样品的量子产率计算，我们需要这些数据。 </li><li>点击文本文件，文件名 ​​"QY型直接照射"（ 视频31）下保存数据。 </li><li>使用数据文件P2_Baseline_Al2O3和P2_Sodium水杨酸 ，我们将计算间接激发的量子产率（32视频 ），现在我们将这个数据保存最终的量子产率计算。 </li><li>点击文本文件和保存的名义下"QY型间接辐射"（33）视频数据的文本文件，现在我们将两个文本文件在Excel中打开方向量子产量数据t和间接激励。最后，我们将计算出样品的量子产率，包括间接激励效果，请使用下列公式计算: </li></ol> Φ=ΦD（1-AD）φI 其中: Φ是更正后的量子产率，考虑到间接激发 ΦD是使 ​​用直接激发内部量子产量。 （内部量子产率，荧光/吸收激发光量的金额。） 广告是直接激发吸收。 （这是样品所吸收的激发光量的比例）。 （吸光度=（AREX - CsEx）/ AREX，其中AREX是激发光量和CsEx是反射光量） φI是使用乐悠内部量子产量矩形励磁 Φ= 0.536 - （1 - 0.848）0.420计算 Φ= 0.47216 6。色度计算<ol><li>随着色度计算准备了一个模板，我们将使用可选软件报表生成。 </li><li>打开数据文件P1_Sodium水杨酸（ 视频34）。 </li><li>单击"属性"按钮，然后在"报告"标签"。在"输出"选择"使用的打印发生器表"，从下拉菜单。在"打印项目"选择模板"FL70Std01_Color-chart.xls"，然后单击"打开"按钮。有没有必要选择的波长范围和间隔，因为这样做自动报告生成器（ 视频35）。 </li><li>下一步是创建报告。点击"报告"标签，将执行宏创建报告和样品名称下保存在"报告"在Excel格式的文件夹（ 视频36）。<html> / LI&gt; <li>这时我们可以打开看到的颜色数据（ 视频37）的报告。 </li></ol> 7。成功的秘诀<ol><li>使用新鲜的样本。 </li><li>要知道，来自不同制造商的材料可以得出不同的结果。 </li><li>点选粉细胞底部压缩样品，并提出了一种用于测量表面均匀。 </li><li>由轻保护样品。他们与光线照射恶化。 </li><li>尝试使用一个更快的扫描速度，以尽量减少样品暴露在光线下。 </li></ol> 8。代表结果 8.1。水杨酸钠是已知的有0.4至0.5的量子产率<img src="/files/ftp_upload/3066/3066fig1.jpg" alt="图1" /> 图1。 <a href="http://jove.com/files/ftp_upload/3066/3066fig1large.jpg" target="_blank">点击这里查看大图</a> 。 iles/ftp_upload/3066/3066fig2.jpg"ALT ="图1"/&gt; 图2。 <a href="http://jove.com/files/ftp_upload/3066/3066fig2large.jpg" target="_blank">点击这里查看大图</a> 。 <img src="/files/ftp_upload/3066/3066fig3.jpg" alt="图1" /> 图3。 <a href="http://jove.com/files/ftp_upload/3066/3066fig3large.jpg" target="_blank">点击这里查看大图</a> 。

<ol>
	<li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Quantum Yield Measurement of Sodium Salicylate. FL080002, 1 (2008).</li><li>Lakowicz, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Principles+of+Fluorescence+Spectroscopy.">Principles of Fluorescence Spectroscopy.</a> Science and Business Media, LLC. 60, (2006).</li><li>Horigome, J., Wakui, T., Shirasaki, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Simple+Correction+Method+for+Determination+of+Absolute+Fluorescence+Quantum+Yields+of+Solid+Samples+with+a+conventional+Fluorescence+Spectrophotometer.">A Simple Correction Method for Determination of Absolute Fluorescence Quantum Yields of Solid Samples with a conventional Fluorescence Spectrophotometer.</a> Bunseki Kagako. 58 (6), 553-559 (2009).</li></ol>

答:路易斯·莫雷诺日立高新技术的美国生产在这篇文章中所使用的仪器是受雇于。

<table border="1"><tbody><tr><td> 试剂名称 </td><td> 公司 </td><td> 目录编号 </td><td> 评论 </td></tr><tr><td>水杨酸钠粉</td><td>瓦科</td><td> 191-03142 </td><td>摩尔。重量160.10 </td></tr></tbody></table>

absolute quantum yield measurement of powder samples

荧光量子产率的测量在寻找新的解决方案的开发，评估，质量控制和照明的研究已成为重要的工具，视听设备，有机EL材料，薄膜，过滤器和生物产业的荧光探针。 量子产率的计算公式为吸收光子的数目比，材料发出的光子的数量。量子产率更高，更好的荧光物质的效率。 对于在本视频的测量，我们将使用日立F-7000荧光光谱仪配备的量子产量测量附件和报告生成程序。所有提供的信息适用于该系统。 粉末样品中的量子产量测量执行以下步骤: <ol><li>生成激励和emiss的仪器校正因子离子单色。这是一个正确的测量量子产量的重要要求。它已在仪器的测量范围提前进行，并不会由于时间的限制，在这个视频显示。 </li><li>积分球校正因子的测量。这一步的目的是要考虑到用于测量积分球反射特性。 </li><li>参考和样品的测量，使用直接激励和间接激励。 </li><li>量子产率的计算使用的直接和间接激励。直接激发样品时，面临着直接的激发光束，这将是正常的测量设置。然而，因为我们使用积分球，从样品的荧光发射的光子的一部分由积分球反射，将重新激发样品，所以我们需要考虑到间接激励。这是ACCOmplished通过测量样品放置在港口面临的发射单色，计算间接量子产率和纠正直接的量子产率计算。 </li><li>纠正量子计算产量。 </li><li>色度坐标计算使用报告生成程序。 </li></ol>日立F-7000量子效率测量系统提供此应用程序的优势，如下: <ul><li>高灵敏度（S / N比800或更好的有效值）。信号是在下列条件下测量:EX波长为350纳米，带通EX和EM为5 nm，响应2秒）水的拉曼光谱，拉曼峰的最大噪声测量。高灵敏度允许测量样品甚至低量子产率。使用这个系统，我们已经测量低至0.1水杨酸的样本和高镁钨样品0.8量子产率。 </li><li>高度精确的测量动态范围的6个订单大小允许双方尖锐的散射峰强度高，以及广泛的荧光峰强度低，在相同条件下进行测量。 </li><li>高测量吞吐量和减少光线照射到样品，由于到高扫描速度可达60,000海里/分钟，自动快门功能。 </li><li>测量量子产量超过宽的波长范围从240至800 nm。 </li><li>精确的量子产率的测量采集仪的光谱响应和整合球体校正因子测量样品的结果。 </li><li>大型专用和易于使用的软件所提供的计算参数的选择。 </li></ul>在这部影片中，我们将测量粉状水杨酸钠，这是众所周知的量子产值的0.4至0.5。

Watch this Scientific Journal Video about Absolute Quantum Yield Measurement of Powder Samples at JoVE.com

Absolute Quantum Yield Measurement of Powder Samples

在这段视频中，我们将演示绝对量子产率和色度坐标直接粉末样品，用日立F-7000量子效率测量系统的测量和计算。

粉末样品的绝对量子产量测量

Measurement of fluorescence quantum yield has become an important tool in the search for new solutions in the development, evaluation, quality control and ...

absolute-quantum-yield-measurement-of-powder-samples

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

27.9K 次观看.  Hitachi High Technologies America. 在这段视频中，我们将演示绝对量子产率和色度坐标直接粉末样品，用日立F-7000量子效率测量系统的测量和计算。

视频: Absolute Quantum Yield Measurement of Powder Samples

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

紧凑型量子点的单分子成像

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

科研

工程学

Structural Information from Single-molecule FRET Experiments Using the Fast Nano-positioning System

Single-molecule F&#246;rster Resonance Energy Transfer (smFRET) can be used to obtain structural information on biomolecular complexes in real-time. Thereby, multiple smFRET measurements are used to localize an unknown dye position inside a protein complex by means of trilateration. In order to obtain quantitative information, the Nano-Positioning System (NPS) uses probabilistic data analysis to combine structural information from X-ray crystallography with single-molecule fluorescence data to calculate not only the most probable position but the complete three-dimensional probability distribution, termed posterior, which indicates the experimental uncertainty. The concept was generalized for the analysis of smFRET networks containing numerous dye molecules. The latest version of NPS, Fast-NPS, features a new algorithm using Bayesian parameter estimation based on Markov Chain Monte Carlo sampling and parallel tempering that allows for the analysis of large smFRET networks in a comparably short time. Moreover, Fast-NPS allows the calculation of the posterior by choosing one of five different models for each dye, that account for the different spatial and orientational behavior exhibited by the dye molecules due to their local environment.
Here we present a detailed protocol for obtaining smFRET data and applying the Fast-NPS. We provide detailed instructions for the acquisition of the three input parameters of Fast-NPS: the smFRET values, as well as the quantum yield and anisotropy of the dye molecules. Recently, the NPS has been used to elucidate the architecture of an archaeal open promotor complex. This data is used to demonstrate the influence of the five different dye models on the posterior distribution.

We present the setup and experimental procedure to obtain smFRET data from large donor-acceptor networks with a TIRF microscope. The step-by-step analysis of these measurements with the Bayesian inference software Fast-NPS yields high-resolved structural information via the application of adapted dye models.

从单分子结构信息FRET实验使用快速纳米定位系统

Single-molecule F&#246;rster Resonance Energy Transfer (smFRET) can be used to obtain structural information on biomolecular complexes in real-time. ...

生物化学

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages include high potential yield, use of non-arable land and integration with waste streams. The nutrient requirements of a large-scale microalgae production system will require the coupling of cultivation systems with industrial waste resources, such as carbon dioxide from flue gas and nutrients from wastewater. Inorganic contaminants present in these wastes can potentially lead to bioaccumulation in microalgal biomass negatively impact productivity and limiting end use. This study focuses on the experimental evaluation of the impact and the fate of 14 inorganic contaminants (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn) on Nannochloropsis salina growth. Microalgae were cultivated in photobioreactors illuminated at 984 &#181;mol m-2 sec-1 and maintained at pH 7 in a growth media polluted with inorganic contaminants at levels expected based on the composition found in commercial coal flue gas systems. Contaminants present in the biomass and the medium at the end of a 7 day growth period were analytically quantified through cold vapor atomic absorption spectrometry for Hg and through inductively coupled plasma mass spectrometry for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Sn, V and Zn. Results show N. salina is a sensitive strain to the multi-metal environment with a statistical decrease in biomass yieldwith the introduction of these contaminants. The techniques presented here are adequate for quantifying algal growth and determining the fate of inorganic contaminants.

Integration of microalgal cultivation with industrial flue gas will ultimately introduce heavy metals and other inorganic compounds into the growth media. This study presents a procedure used to determine the end fate and impact of heavy metals and inorganic contaminants on the growth of Nannochloropsis salina grown in photobioreactors.

重金属和微藻的产其他无机污染物的量化

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages ...

环境科学

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 &#956;m from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,&#945;&#947;)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

We illustrate the application of 1H(15N,&#945;&#947;)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.

通过与核反应分析深度剖面的表面和界面层和颗粒材料氢含量的定量

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and ...

Quantifying X-Ray Fluorescence Data Using MAPS

The quantification of X-ray fluorescence (XRF) microscopy maps by fitting the raw spectra to a known standard is crucial for evaluating chemical composition and elemental distribution within a material. Synchrotron-based XRF has become an integral characterization technique for a variety of research topics, particularly due to its non-destructive nature and its high sensitivity. Today, synchrotrons can acquire fluorescence data at spatial resolutions well below a micron, allowing for the evaluation of compositional variations at the nanoscale. Through proper quantification, it is then possible to obtain an in-depth, high-resolution understanding of elemental segregation, stoichiometric relationships, and clustering behavior.
This article explains how to use the MAPS fitting software developed by Argonne National Laboratory for the quantification of full 2-D XRF maps. We use as an example results from a Cu(In,Ga)Se2 solar cell, taken at the Advanced Photon Source beamline 2-ID-D at Argonne National Laboratory. We show the standard procedure for fitting raw data, demonstrate how to evaluate the quality of a fit and present the typical outputs generated by the program. In addition, we discuss in this manuscript certain software limitations and offer suggestions for how to further correct the data to be numerically accurate and representative of spatially resolved, elemental concentrations.

Here, we demonstrate the use of the X-ray fluorescence fitting software, MAPS, created by Argonne National Laboratory for the quantification of fluorescence microscopy data. The quantified data that results is useful for understanding the elemental distribution and stoichiometric ratios within a sample of interest.

利用地图量化 X 射线荧光数据

The quantification of X-ray fluorescence (XRF) microscopy maps by fitting the raw spectra to a known standard is crucial for evaluating chemical ...

化学

Reliable Mechanochemistry: Protocols for Reproducible Outcomes of Neat and Liquid Assisted Ball-mill Grinding Experiments

The equilibrium outcomes of ball mill grinding can dramatically change as a function of even tiny variations in the experimental conditions such as the presence of very small amounts of added solvent. To reproducibly and accurately capture this sensitivity, the experimentalist needs to carefully consider every single factor that can affect the ball mill grinding reaction under investigation, from ensuring the grinding jars are clean and dry before use, to accurately adding the stoichiometry of the starting materials, to validating that the delivery of solvent volume is accurate, to ensuring that the interaction between the solvent and the powder is well understood and, if necessary, a specific soaking time is added to the procedure. Preliminary kinetic studies are essential to determine the necessary milling time to achieve equilibrium. Only then can exquisite phase composition curves be obtained as a function of the solvent concentration under ball mill liquid assisted grinding (LAG). By using strict and careful procedures analogous to the ones here presented, such milling equilibrium curves can be obtained for virtually all milling systems. The system we use to demonstrate these procedures is a disulfide exchange reaction starting from the equimolar mixture of two homodimers to obtain at equilibrium quantitative heterodimer. The latter is formed by ball mill grinding as two different polymorphs, Form A and Form B. The ratio R = [Form B] / ([Form A] + [Form B]) at milling equilibrium depends on the nature and concentration of the solvent in the milling jar.

We present detailed procedures to produce experimental equilibrium curves of the phase composition as a function of solvent concentration in a solid state system under milling conditions.

可靠的化学: 整洁和液体辅助球磨机研磨试验的可再生结果协议

The equilibrium outcomes of ball mill grinding can dramatically change as a function of even tiny variations in the experimental conditions such as the ...

Synthesis of In37P20(O2CR)51 Clusters and Their Conversion to InP Quantum Dots

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 clusters have been observed as intermediates in the synthesis of InP quantum dots from molecular precursors (In(O2CR)3, HO2CR, and P(SiMe3)3) and may be isolated as a pure reagent for subsequent study and use as a single-source precursor. These clusters readily convert to crystalline and relatively monodisperse samples of quasi-spherical InP quantum dots when subjected to thermolysis conditions in the absence of additional precursors above 200 &#176;C. The optical properties, morphology, and structure of both the clusters and quantum dots are confirmed using UV-Vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, and powder X-ray diffraction. The molecular symmetry of the clusters is additionally confirmed by solution-phase 31P NMR spectroscopy. This protocol demonstrates the preparation and isolation of atomically-precise InP clusters, and their reliable and scalable conversion to InP QDs.

Synthesis of In37P20O2CR51 Clusters and Their Conversion to InP Quantum Dots

A protocol for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots is presented.

37p20 (o2cr)51聚类中的合成及其转化为 inp 量子点

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 ...

Three-Dimensional Particle Shape Analysis Using X-ray Computed Tomography: Experimental Procedure and Analysis Algorithms for Metal Powders

Measuring the size distribution of the particles in a powder is a common activity in science and industry. Measuring the shape distribution of the particles is much less common. However, the shape and size of powder particles are not independent quantities. All known size/shape measurement techniques either assume a spherical shape or measure the shape in two dimensions only. The X-ray computed tomography (XCT) based method presented here measures both size and shape in 3D without making any assumptions. Starting from a 3D image of particles, the method can mathematically classify particles according to shape, for example particles composed of several smaller particles welded together as opposed to single particles that are not necessarily spherical. Of course, defining a single number as the &#34;size&#34; or &#34;shape&#34; of a random non-spherical particle is not possible in principle, leading to many ways to estimate particle size and shape via various interlinked parameters, which can all be generated from this complete 3D characterization in the form of averages and distributions. The necessary experimental procedures, mathematical analysis, and computer analysis are described and an example is given for a metal powder. The technique is limited to particles that can be imaged by XCT with a minimum of about 1000 voxels per particle volume.

The size and shape of powder particles are not independent quantities. Usual measurement techniques do not measure these intertwined parameters in three dimensions (3D). A 3D measurement/analysis technique is described, based on X-ray computed tomography, which can measure size and shape and classify powder particles according to both parameters.

Measuring the size distribution of the particles in a powder is a common activity in science and industry. Measuring the shape distribution of the ...

UV-Vis Spectroscopic Characterization of Nanomaterials in Aqueous Media

The physicochemical characterization of nanomaterials (NMs) is often an analytical challenge, due to their small size (at least one dimension in the nanoscale, i.e. 1&#8211;100 nm), dynamic nature, and diverse properties. At the same time, reliable and repeatable characterization is paramount to ensure safety and quality in the manufacturing of NM-bearing products. There are several methods available to monitor and achieve reliable measurement of nanoscale-related properties, one example of which is Ultraviolet-Visible Spectroscopy (UV-Vis). This is a well-established, simple, and inexpensive technique that provides non-invasive and fast real-time screening evaluation of NM size, concentration, and aggregation state. Such features make UV-Vis an ideal methodology to assess the proficiency testing schemes (PTS) of a validated standard operating procedure (SOP) intended to evaluate the performance and reproducibility of a characterization method. In this paper, the PTS of six partner laboratories from the H2020 project ACEnano were assessed through an interlaboratory comparison (ILC). Standard gold (Au) colloid suspensions of different sizes (ranging 5&#8211;100 nm) were characterized by UV-Vis at the different institutions to develop an implementable and robust protocol for NM size characterization.

This study presents the benchmarking results for an interlaboratory comparison (ILC) designed to test the standard operating procedure (SOP) developed for gold (Au) colloid dispersions characterized by ultraviolet-visible Spectroscopy (UV-Vis), amongst six partners from the H2020 ACEnano project for sample preparation, measurement, and analysis of the results.

水介质中纳米材料的紫外-可见光谱表征

The physicochemical characterization of nanomaterials (NMs) is often an analytical challenge, due to their small size (at least one dimension in the ...

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch

Photoswitching organic molecules that undergo light-driven structural transformations are key components to construct adaptive molecular systems, and they are utilized in a wide variety of applications. In most studies employing photoswitches, several important photophysical properties such as maximum wavelengths of absorption and emission, molar attenuation coefficient, fluorescence lifetime, and photoisomerization quantum yield are carefully determined to investigate their electronic states and transition processes. However, measurement of the photoisomerization quantum yield, the efficiency of photoisomerization with respect to the absorbed photons, in a typical laboratory setting is often complicated and prone to error because it requires the implementation of rigorous spectroscopic measurements and calculations based on an appropriate integration method. This article introduces a set of procedures to measure the photoisomerization quantum yield of a bistable photoswitch using a photochromic hydrazone. We anticipate that this article will be a useful guide for the investigation of bistable photoswitches that are being increasingly developed.

Photoisomerization quantum yield is a fundamental photophysical property that should be accurately determined in the investigation of newly developed photoswitches. Here, we describe a set of procedures to measure the photoisomerization quantum yield of a photochromic hydrazone as a model bistable photoswitch.

氢化光开关光异构化量子产率的测定

Photoswitching organic molecules that undergo light-driven structural transformations are key components to construct adaptive molecular systems, and they ...