作者衷心的Labex-内蒙科大承认的财政支持。

1，生物样品制备 所有在本研究中所描述的实验的CECCAPP（法国里昂）（授权＃LYONSUD_2012_004）的动物护理和使用委员会批准，并在实验授权的个人（L. Sancey，DDPP授权＃的监督下进行38 05 32）。 <ol><li>新增1对H 2 O毫升至100微摩尔钆（Gd）为基础纳米粒子，等待15分钟，然后加入20微升的HEPES 50 mM时，氯化钠1.325 M， 氯化钙 20毫米至100微升H 2 O和80微升基于Gd的纳米颗粒的初级溶液，得到200μl的溶液，在40 mM的现成的喷出（城市：维勒，在实验室中）。 </li><li>注入200微升钆为基础的纳米粒子溶液静脉滴注进入麻醉荷瘤啮齿类动物（城市：里昂南方（Oullins），从实验室15公里），。 </li><li> 1-24小时注射后，牺牲的小鼠d将生物样品为异戊烷用液氮冷却。储存样品 - 80℃（城市：里昂南方（Oullins），15从实验室公里）。 </li><li>切片样本（城市：通常格勒诺布尔，从LAB 100公里，我会尽量在里昂南方接入）在100微米厚的幻灯片，并把生物玻片上的特定塑料培养皿（培养皿）。储存在-80℃。 注：塑料菜基本上是一个非常纯粹的聚合物样品。它们被用来避免与包含在组织中的元素的干扰。 </li></ol> 2，样品制备校准 <ol><li>制备小瓶用递增剂量的基于Gd的纳米颗粒入水（0纳米，100纳米，500纳米，1μM，5μM，10μM，50μM，100μM，500μM，1毫米，和5mM）。 </li><li>把5微升降了3毫米的培养皿规则排列的每个解决方案。 </li><li>干燥在室温下20分钟。 </li></ol>3，激光诱导击穿光谱实验<ol><li>初始化设置LIBS <ol><li>激光设置。在仪器开机后，等待10-20分钟的激光脉冲能量稳定性和冷却ICCD相机低至-20°C。用衰减器调节的脉冲能量。 注意：最佳激光参数映射组织是5毫微秒脉冲持续时间，1064纳米波长和大约4毫焦耳的脉冲能量。激光采用的是一个典型的Nd：YAG纳秒激光。 </li><li> LIBS设置。设置激光聚焦位置（相对于所述样品表面），以获得更小的坑直径（大约50微米或更小）。 注意：这对应于一个激光脉冲聚焦100μm的试样表面以下。 </li><li>光谱仪的设置。使用柴尔尼 - 特纳光谱结合了1200线/毫米的光栅和高时间分辨率的ICCD相机。由计算机控制所有这些设备。输入狭缝值设置为40微米。置的光谱范围重新褒贬要分析的元素。使用光谱范围覆盖325到355纳米检测钆具有高灵敏度，以及钠，铜和钙。为300毫微秒的延迟，为2微秒的栅极，和200的增益设定的ICCD参数。 </li></ol></li><li>测绘测量<ol><li>将生物样品的LIBS机动样品架。 </li><li>根据该激光焦点位置调整样品的高度。 </li><li>取样品切片的高分辨率照片。 </li><li>设置LIBS采集软件的映射模块与由约100微米的分辨率间距通常为100×100个测量点进行映射。 </li><li>开始采集。从这点自动应有尽有;运动序列以及频谱记录和保存。 40分钟所需要的10000点的映射（相当于1 平方厘米为100μm的分辨率）。重组所有记录的频谱划分为同一个文件。 </li><li>当finished，取试样片的第二张照片</li></ol></li><li>校准测量</li></ol>用相同的实验参数，测量校准样品（制备的详细信息，请参见第2节）。执行在每个校准滴的地图或记录25光谱（从在下拉的中心部分测点获得）。 4 LIBS谱分析：构建化学图像 <ol><li>记录从组织映射所有的LIBS光谱并加载它们在LIBS软件分析。减去基准为每个频谱，并用假彩色构造的化学与图像强度的相对规模。 注：算法检索特定的谱线强度，如钆，铜，钠，钙或。 </li><li>从校准样品测得的光谱，使校准曲线计算（强度与浓度之间的关系），并建立AQ执行相同的操作uantitative地图或图像钆（或其他感兴趣的元素）。 </li><li>应用适当的治疗，以化学的图像，诸如内插或平滑。在保存的图像格式（位图）的强度或浓度地图。 </li></ol>

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作者什么都没有透露。

应用于生物样品，该技术允许化学成像， 即钆和Si从不同器官注射钆为基础的纳米粒子的映射和量化。从主关键设置，激光特性（波长，脉冲能量，聚焦，和稳定性）的控制是要精确和微细组织消融（ 即映射分辨率）以及灵敏度的关键。工作在高能量提供了一个更好的灵敏度，但遗憾的是产生退化的空间分辨率。此外，使用光谱仪的类型必须仔细检查。基本上，一个宽带的调查（例...

纳米粒子的生物应用的广阔的发展要求为他们的量化和成像生物样品中的分析技术同步提高。通常在器官纳米颗粒的检测和映射是由荧光或共聚焦显微镜进行。不幸的是这些方法中所需要的纳米颗粒的通过近红外线的染料，可以修改该纳米颗粒的生物分布，尤其是对于由于其疏水特性非常小的纳米颗粒标记。标记的纳米颗粒，特别是非常小的纳米粒子（粒径&lt;10纳米）的检测，因此可能与他们的干扰生物分布在全身的规模，而且在组织和细胞水平。中能检测纳米粒子没有任何标签的新设备的开发提供了自己的行为和动力学研究新的可能性。此外，微量元素，如铁和铜中脑的作用毛病的ð神经变性疾病如阿尔茨海默1，门克斯2,3，或威尔逊4表明兴趣来研究和定位在组织中这些元素。 各种技术已被用来提供不同材料的元素映射或微量分析。在2006年发表的综述文章，R. Lobinski 等，提供在生物环境中，最具挑战性的环境中进行分析科学5中的一个元素微量可用标准技术的概述。电子探针，其由在透射电子显微镜能量分散型X-射线微量分析的，可以应用于大量的研究，如果该元素的浓度是足够的（&gt; 100-1000微克/克）。为了达到更低的检出限，下面的技术已被用来： <ul><li>利用离子束微探针粒子激发X射线发射μ-PIXE（1-10微克/克）6 </li><li>同步chrotron微量辐射μ-SXRF（0.1-1微克/克）7 </li><li>二次离子质谱（SIMS 0.1微克/克）8 </li><li>激光烧蚀电感耦合质谱LA-ICP-MS（下降到0.01微克/克）9,10 </li></ul>上述技术提供了微米级的分辨率，如图从Lobinski 等中提取的表1中 。 串行2D调查三维重建也可提出深层组织11重建。然而，所有的设备和系统的要求都合格的专业人员，中度至高度昂贵的设备和持久的实验（通常多于4小时的100微米×100微米μ-SXRF和10毫米×10毫米为LA-ICP-MS的）12。总之，这些要求使得元素微量非常限制，与传统的光学成像系统不兼容，荧光显微镜或非线性显微镜。我们可以在这里提到的另一点是，定量测量能力还是相当有限的，取决于基质匹配实验室标准的可用性。在行业流程，地质学，生物学和应用等领域的使用元素微量的进一步推广将产生显著的概念和技术突破。 本稿件的目的是提出在生物组织定量元素映射（或元素微量分析）溶液用桌面仪器与常规光学显微镜完全兼容。我们的方法是基于激光诱导击穿光谱（LIBS技术）。在LIBS，激光脉冲被聚焦于感兴趣的样品以建立该材料的击穿和火花。在等离子体中发射的原子辐射随后通过分光计和elemen分析TAL的浓度可以检索与事先13,14进行校准测量。 LIBS技术的优点包括：灵敏度（微克/克，几乎所有的元素），体积小，非常基本的样品制备，缺乏与样品接触，瞬时响应，准确的本地化（微）表面分析。然而，组织化学成像的应用仍然具有挑战性，因为组织的激光消融，必须精确地控制，以高空间分辨率与在微克/克范围15,16灵敏度一起执行映射。 用这样的解决方案，则不需要示踪剂或标记试剂的红利，它允许直接在其天然环境中检测生物组织中的无机元素。在激光诱导击穿光谱仪在我们的实验室开发提供了一个电流分辨率逊色于100微米与钆低于35微克/克的估计灵敏度，相当于0.1毫米16，这使得大样本的映射（&gt; 1 平方厘米）在30分钟内。此外，国产软件方便了数据的采集和利用。这个仪器是用来检测，映射和量化钆的组织分布（Gd）的基于纳米颗粒的17 - 18在肾和肿瘤样本来自小动物，1至24小时静脉注射颗粒后（粒径&lt;5nm）的。无机元素，它在本质上是包含在生物组织中，如铁，钙，钠，和P，也已经检测到并成像。

<table border="0" cellpadding="0" cellspacing="0" width="747">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laser nanosecond Nd:YAG</td>
			<td style="width:129px;">Quantel</td>
			<td style="width:119px;">Brillant</td>
			<td style="width:283px;">5ns pulse witdh, wavelength 1064 nm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Spectrometer</td>
			<td>Andor Technology</td>
			<td>Shamrock 303</td>
			<td>with 1200 l/mm blazed at 300 nm grating</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Detector ICCD</td>
			<td>Andor Technology</td>
			<td style="width:119px;">Istar</td>
			<td>2 ns temporal resolution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">LIBS Unit</td>
			<td style="width:129px;">ILM</td>
			<td style="width:119px;"></td>
			<td>Homemade Instrumentation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:129px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gd-based nanoparticles</td>
			<td style="width:129px;">Nano-H</td>
			<td style="width:119px;"></td>
			<td>particles</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">HEPES</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">H4034</td>
			<td>for particle&#39;s dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">CaCl2</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">21108</td>
			<td>for particle&#39;s dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">NaCl</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">S5886</td>
			<td>for particle&#39;s dilution</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">mice</td>
			<td style="width:129px;">Charles River</td>
			<td style="width:119px;">depending of animal breeding</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">isoflurane</td>
			<td style="width:129px;">Coveto / Virbac</td>
			<td style="width:119px;"></td>
			<td>for anaesthesia - Isofluranum</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">isopentane</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">59060</td>
			<td>to froze the sample&#160; slowly</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">liquide nitrogen</td>
			<td style="width:129px;">Air Liquide</td>
			<td style="width:119px;"></td>
			<td>to cool down the isopentane</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">cryostat</td>
			<td style="width:129px;">Leica</td>
			<td style="width:119px;">CM-3050S</td>
			<td>to slide the samples</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">petri dishes</td>
			<td style="width:129px;">Dutscher</td>
			<td style="width:119px;">353004</td>
			<td>to stick the sample</td>
		</tr>
	</tbody>
</table>

laser-induced breakdown spectroscopy: a new approach for nanoparticle's mapping and quantification in organ tissue

激光诱导等离子体的发射光谱应用于生物样品的元素分析。上薄切片啮齿动物组织中的激光诱导击穿光谱（LIBS）执行：肾脏肿瘤，使无机元素，例如（i）钠，钙，铜，镁，磷，铁，天然存在于体内并检测（ⅱ）的Si和Gd，注射钆为基础的纳米颗粒后进行检测。使动物安乐死静脉注射颗粒后1至24小时。试样的二维扫描，执行使用电动测微三维阶段，允许的红外激光束探索表面具有横向分辨率小于100μ米。器官内钆元素的定量化学图像，与亚毫米感光度获得。 LIBS提供研究无机材料的分发没有任何具体的labeli一个简单而可靠的方法NG。此外，与标准的光学显微镜的安装程序的兼容性强调它的潜力，以提供相同的生物组织的多个图像与不同类型的反应：元素，分子，或细胞。

如图1所示 ，Nd组成的光束：YAG激光器中的1064纳米的基波波长是由50毫米焦距的石英透镜聚焦垂直向下的组织切片上。脉冲能量为4毫焦耳，重复频率10赫兹。为了避免空气中的等离子体的产生，该激光束被聚焦大约100微米的样品的表面下。没有空气等离子体中观察到这种情况。在实验过程中，将样品通过一个步进电机，以便产生一个等离子体中只有一个样品上（单发）的位置移动。显...

Watch this Scientific Journal Video about Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue at JoVE.com

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle&#039;s Mapping and Quantification in Organ Tissue

薄器官和肿瘤组织进行激光诱导击穿光谱检测成功自然元素和人工注射钆（Gd），从钆为基础的纳米粒子发出。化学元素的图像达到100微米和定量分毫灵敏度的分辨率。与标准的光学显微镜设置的兼容性强调其潜力提供一个相同的生物组织的多张图片。

激光诱导击穿光谱：对于纳米粒子的映射和定量的器官组织的新方法

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) ...

laser-induced-breakdown-spectroscopy-new-approach-for-nanoparticle-s

Research

JoVE Journal

Engineering

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

13.6K 次观看.  CNRS - Université Lyon 1. 薄器官和肿瘤组织进行激光诱导击穿光谱检测成功自然元素和人工注射钆（Gd），从钆为基础的纳米粒子发出。化学元素的图像达到100微米和定量分毫灵敏度的分辨率。与标准的光学显微镜设置的兼容性强调其潜力提供一个相同的生物组织的多张图片。 

视频: Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

在极低的温度下角分辨光电子能谱

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

科研

工程学

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

在固体氧化物燃料电池电极表面的探测和测绘

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen ...

Scanning-probe Single-electron Capacitance Spectroscopy

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the electronic quantum structure of small systems - including individual atomic dopants in semiconductors. Here we present a capacitance-based method, known as Subsurface Charge Accumulation (SCA) imaging, which is capable of resolving single-electron charging while achieving sufficient spatial resolution to image individual atomic dopants. The use of a capacitance technique enables observation of subsurface features, such as dopants buried many nanometers beneath the surface of a semiconductor material1,2,3. In principle, this technique can be applied to any system to resolve electron motion below an insulating surface.
As in other electric-field-sensitive scanned-probe techniques4, the lateral spatial resolution of the measurement depends in part on the radius of curvature of the probe tip. Using tips with a small radius of curvature can enable spatial resolution of a few tens of nanometers. This fine spatial resolution allows investigations of small numbers (down to one) of subsurface dopants1,2. The charge resolution depends greatly on the sensitivity of the charge detection circuitry; using high electron mobility transistors (HEMT) in such circuits at cryogenic temperatures enables a sensitivity of approximately 0.01 electrons/Hz&frac12; at 0.3 K 5.

Scanning-probe single-electron capacitance spectroscopy facilitates the study of single-electron motion in localized subsurface regions. A sensitive charge-detection circuit is incorporated into a cryogenic scanning probe microscope to investigate small systems of dopant atoms beneath the surface of semiconductor samples.

扫描探针单电子电容谱

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the ...

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement is used. Here we operate a Nd:YAG laser at a frequency of 10 Hz at the fundamental wavelength of 1,064 nm. The 14 nsec pulses with anenergy of 190 mJ/pulse are focused to a 50 &#181;m spot size to generate a plasma from optical breakdown or laser ablation in air. The microplasma is imaged onto the entrance slit of a 0.6 m spectrometer, and spectra are recorded using an 1,800 grooves/mm grating an intensified linear diode array and optical multichannel analyzer (OMA) or an ICCD. Of interest are Stark-broadened atomic lines of the hydrogen Balmer series to infer electron density. We also elaborate on temperature measurements from diatomic emission spectra of aluminum monoxide (AlO), carbon (C2), cyanogen (CN), and titanium monoxide (TiO).
The experimental procedures include wavelength and sensitivity calibrations. Analysis of the recorded molecular spectra is accomplished by the fitting of data with tabulated line strengths. Furthermore, Monte-Carlo type simulations are performed to estimate the error margins. Time-resolved measurements are essential for the transient plasma commonly encountered in LIBS.

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

Time-resolved atomic and diatomic molecular species are measured using LIBS. The spectra are collected at various time delays following the generation of optical breakdown plasma with Nd:YAG laser radiation&#160;and are analyzed to infer electron density and temperature.

测量和原子氢和双原子分子ALO，C分析<sub&gt; 2</sub&gt;，CN和二氧化钛光谱承接激光诱导光学击穿

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement ...

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With ~102-103 repetitions of the photoreaction, the minimum number to complete a scan at reasonable spectral resolution and bandwidth, the noise level in the absorption difference spectra can be as low as ~10-4, sufficient to follow the kinetics of protonation changes from a single amino acid. Lower noise levels can be accomplished by more data averaging and/or mathematical processing. The amount of protein required for optimal results is between 5-100 &#181;g, depending on the sampling technique used. Regarding additional requirements, the protein needs to be first concentrated in a low ionic strength buffer and then dried to form a film. The protein film is hydrated prior to the experiment, either with little droplets of water or under controlled atmospheric humidity. The attained hydration level (g of water / g of protein) is gauged from an IR absorption spectrum. To showcase the technique, we studied the photocycle of the light-driven proton-pump bacteriorhodopsin in its native purple membrane environment, and of the light-gated ion channel channelrhodopsin-2 solubilized in detergent.

Key steps of protein function, in particular backbone conformational changes and proton transfer reactions, often take place in the microsecond to millisecond time scale. These dynamical processes can be studied by time-resolved step-scan Fourier-transform infrared spectroscopy, in particular for proteins whose function is triggered by light.

质子转移和蛋白质构象动力学的光敏蛋白的时间分辨步进扫描傅立叶变换红外光谱

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards ...

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. The aggressive scaling of feature sizes, both on devices and interconnects, leads to serious challenges to ensure the required product reliability. Standard reliability tests and post-mortem failure analysis provide only limited information about the physics of failure mechanisms and degradation kinetics. Therefore it is necessary to develop new experimental approaches and procedures to study the TDDB failure mechanisms and degradation kinetics in particular. In this paper, an in situ experimental methodology in the transmission electron microscope (TEM) is demonstrated to investigate the TDDB degradation and failure mechanisms in Cu/ULK interconnect stacks. High quality imaging and chemical analysis are used to study the kinetic process. The in situ electrical test is integrated into the TEM to provide an elevated electrical field to the dielectrics. Electron tomography is utilized to characterize the directed Cu diffusion in the insulating dielectrics. This experimental procedure opens a possibility to study the failure mechanism in interconnect stacks of microelectronic products, and it could also be extended to other structures in active devices.

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. This paper demonstrates the procedure of an in situ TDDB experiment in the transmission electron microscope, which opens a possibility to study the failure mechanism in microelectronic products.

在透射电子显微镜原位时间相关的介质击穿：一种可能性，了解微电子器件的失效机理

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. ...

Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics industry. In this technique the chip and/or the substrate is bumped and the two are bonded via these conductive bumps. Many bumping techniques have been developed and intensively investigated since the introduction of the FC technology in 19601 such as stencil printing, stud bumping, evaporation and electroless/electroplating2. Despite the progress that these methods have made they all suffer from one or more than one drawbacks that need to be addressed such as cost, complex processing steps, high processing temperatures, manufacturing time and most importantly the lack of flexibility. In this paper, we demonstrate a simple and cost-effective laser-based bump forming technique known as Laser-induced Forward Transfer (LIFT)3. Using the LIFT technique a wide range of bump materials can be printed in a single-step with great flexibility, high speed and accuracy at RT. In addition, LIFT enables the bumping and bonding down to chip-scale, which is critical for fabricating ultra-miniature circuitry.

We demonstrate the use of the Laser-induced Forward Transfer (LIFT) technique for flip-chip assembly of optoelectronic components. This approach provides a simple, cost-effective, low-temperature, fast and flexible solution for fine-pitch bumping and bonding on chip-scale for achieving high-density circuits for optoelectronic applications.

激光诱导转发转移单人死于倒装芯片封装

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics ...

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial resolution, and is even capable of providing atomically resolved elemental maps. In this technique, a highly focused electron beam is incident upon a thin sample and the energy of emitted X-rays is measured in order to determine the atomic species of material within the beam path. This elementally sensitive spectroscopy technique can be extended to three dimensional tomographic imaging by acquiring multiple spectrum images with the sample tilted along an axis perpendicular to the electron beam direction.
Elemental distributions within single nanoparticles are often important for determining their optical, catalytic and magnetic properties. Techniques such as X-ray tomography and slice and view energy dispersive X-ray mapping in the scanning electron microscope provide elementally sensitive three dimensional imaging but are typically limited to spatial resolutions of &gt; 20 nm. Atom probe tomography provides near atomic resolution but preparing nanoparticle samples for atom probe analysis is often challenging. Thus, elementally sensitive techniques applied within the scanning transmission electron microscope are uniquely placed to study elemental distributions within nanoparticles of dimensions 10-100 nm.
Here, energy dispersive X-ray (EDX) spectroscopy within the STEM is applied to investigate the distribution of elements in single AgAu nanoparticles. The surface segregation of both Ag and Au, at different nanoparticle compositions, has been observed.

The use of energy dispersive X-ray tomography in the scanning transmission electron microscope to characterize elemental distributions within single nanoparticles in three dimensions is described.

能量色散X射线断层摄影术对个人纳米3D元素映射

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

检测和钯的回收，从城市矿山黄金和钴金属使用标有纳米货车车轮形的孔隙新型传感器/吸附剂

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Blast Quantification Using Hopkinson Pressure Bars

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

This protocol details the use of Hopkinson pressure bars to measure reflected blast loading from near-field explosive events. It is capable of interpolating a pressure-time history at any point on a reflective boundary and as such can be used to fully characterize the spatial and temporal variations in loading produced.

高炉利用定量霍普金森杆

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures ...