红外显微系统在法庭科学领域中的最新应用

结合实例综述红外显微技术在法庭科学中的最新应用。包括使用ATR,金刚石池和智能机械手等附件以及透射,反射和ATR等检测模式,对油漆,纤维,染料,塑料,橡胶,油墨,药物和毒品等物证进行分析。     

飞秒时间分辨的能谱分析光电子显微镜：异质结超快载流子动力学测量

本文成功搭建了一套集成了能谱分析功能的时间分辨光电子显微镜系统(TR-PEEM),能够对电子密度分布进行时间分辨和能量分辨的成像.这套4D显微镜在空间、时间、能量多维度获取电子动力学信息提供了前所未有的手段.本文使用184 fs的时间分辨、150 meV的能量分辨和优于150 nm的空间分辨对半导体进行了测量,在Si(111)表面的Pb岛上获得了微区光电子能谱和能量分辨的TR-PEEM图像.实验结果表明,这套系统是进行异质结载流子动力学观察的有力工具,有助于在亚微米/纳米空间尺度和超快时间尺度上加深对半导体性质的理解.     

Vibrational Spectroscopy in Clinical Analysis

Abstract: Vibrational spectroscopy includes several different techniques, the most important of which are mid-infrared (IR), near-IR, and Raman spectroscopy. Raman and mid-IR spectroscopy are complementary techniques and usually both are required to completely measure the vibrational modes of a molecule. Vibrational spectrometry covers a series of well-established analytical methodologies suitable to be employed for both qualitative and quantitative purposes. In the first part of this review, we will focus on theoretical aspects related to vibrational techniques; in the second part, the most important papers, published during the period 2005–2014, related to clinical analysis performed with vibrational spectroscopy techniques will be critically discussed.     

Nanoscale Imaging and Stabilization of Silica Nanospheres in Liquid Phase Transmission Electron Microscopy

Liquid phase transmission electron microscopy (LP‐TEM) is a novel and highly promising technique for the in situ study of important nanoscale processes, in particular the synthesis and modification of various nanostructures in a liquid. Destabilization of the samples, including reduction, oxidation, or dissolution by interactions between electron beam, liquid, and sample, is still one of the main challenges of this technique. This work focuses on amorphous silica nanospheres and the phenomena behind their reshaping and dissolution in LP‐TEM. It is proposed that silica degradation is primarily the result of reducing radical formation in the liquid phase and the subsequent accelerated hydroxylation of the silica, while alterations in silica solid structure, pH, and oxidizing species formation had limited influence. Furthermore, the presence of water vapor instead of liquid water also results in degradation of silica. Most importantly however, it is shown that the addition of scavengers for reducing radicals significantly improved amorphous silica stability during LP‐TEM imaging. Devising such methods to overcome adverse effects in LP‐TEM is of the utmost importance for further development and implementation of this technique in studies of nanoscale processes in liquid.     

Material Discrimination in Nanoparticle Hetero-Aggregates by Analysis of Scanning Transmission Electron Microscopy Images

Hetero-contacts are interfaces between different materials at the nanoscale leading to novel functional properties. In hetero-aggregates, primary particles of at least two different materials are mixed at primary particle or cluster level. Double flame spray pyrolysis (DFSP) is a versatile technique for the controlled synthesis of such materials. Characterization of hetero-aggregates by scanning transmission electron microscopy (STEM) requires acquisition and evaluation of many aggregate images in order to derive statistically significant results. Usually, STEM energy dispersive X-ray spectroscopy (EDXS) is used to acquire elemental maps providing the material distribution of the primary particles within hetero-aggregates. However, the acquisition of a single EDXS map takes up to several minutes. For this reason, determination of material types of primary particles from the intensity in high-angle annular dark field STEM images alone is desirable. These images can be acquired within a couple of seconds. In the present work, a method is suggested which allows for achieving this objective. It can be applied to distinguish materials with a significant difference in their atomic number and hence sufficient material contrast in the STEM images.     

Quantum Dots Microstructural Metrology: From Time-Resolved Spectroscopy to Spatially Resolved Electron Microscopy

Colloidal quantum dots (QDs) have unique optical and electrical properties with promising applications in next-generation semiconductor technologies, including displays, lighting, solar cells, photodetectors, and image sensors. Advanced analytical tools to probe the optical, morphological, structural, compositional, and electrical properties of QDs and their ensemble solid films are of paramount importance for the understanding of their device performance. In this review, comprehensive studies on the state-of-the-art metrology approaches used in QD research are introduced, with particular focus on time-resolved (TR) and spatially resolved (SR) spectroscopy and microscopy. Through discussing these analysis techniques in different QD system, such as various compositions, sizes, and shell structures, the critical roles of these TR-spectroscopic and SR-microscopic techniques are highlighted, which provide the structural, morphological, compositional, optical, and electrical information to precisely design QDs and QD solid films. The employment of TR and SR analysis in integrated QD device systems is also discussed, which can offer detailed microstructural information for achieving high performance in specific applications. In the end, the current limitations of these analytical tools are discussed, and the future development of the possibility of interdisciplinary research in both QD fundamental and applied fields is prospected.     

Open-path Fourier transform spectroscopy of gas emissions from Oldoinyo Lengai volcano, Tanzania

We report here novel field spectroscopic measurements of the proportions of H₂O, CO₂, CO and SO₂ in gas emissions from Oldoinyo Lengai, the world's unique, active carbonatite volcano. We found that CO₂ constitutes <40 mol% of emissions from a lava lake, and 25 mol% from a cooler fumarole vent. These results suggest that H₂O is the predominant gas phase rather than CO₂, as reported in previous studies based on conventional sampling (Trans. Am. Geophys. Union 69 (1998) 1466; J. Geophys. Res. 101 (1996) 13819), though it is possible that water is introduced by remelting of older hydrated lava flows. We also observed rapid variations in CO₂/CO molar ratios (between 450 and 750 in 1 h) in the lava lake emissions, which could reflect mixing of gases exsolved from deep and shallow magma. Lengai's measured CO₂ flux (J. Geophys. Res. 101 (1996) 13819; Geology 23 (1995) 933) exceeds the time-averaged magma discharge rate, suggesting efficient separation of carbon and water-rich fluids from unerupted silicate magma. This may play an important role in parental magma differentiation.     

原位动态电子显微学研究进展

随着电镜内原位技术的不断成熟和发展,透射电子显微镜不再仅仅是材料结构表征的工具,还是实现高精度纳米加工、性能测试等的重要手段。这不但丰富了纳米尺度下开展实验研究的方法,也拓宽了透射电子显微镜的应用范围,为纳米科学与技术的迅速发展提供了新的契机。本文侧重作者所在研究小组的研究工作,以"将纳米实验室建在透射电子显微镜里"的构想为主线,从材料的原位生长、结构加工、性能表征和器件构建等四个方面综述了近年来基于透射电子显微镜的代表性原位实验研究进展。     

Metal–Polymer Hybrid Nanoparticles for Correlative High‐Resolution Light and Electron Microscopy

The combination of fluorescence microscopy and electron microscopy promises a deeper insight into the ultrastructural features of cell organelles, e.g., after drug administration. Both methods complement each other and provide, as a correlative approach, a keen insight into the fate of nanoparticles within the cell. Moreover, it represents a promising tool to determine alterations of the cellular environment as a response to particle uptake. However, the availability of suitable correlative markers is mandatory for such correlative approaches. In this contribution, the utilization of poly(ethylene imine) based metal–polymer hybrid particles labeled with small gold nanoparticles and Rhodamine B facilitating the observation of the particles by means of fluorescence as well as by transmission electron microscopy is suggested. Correlative light and electron microscopy is used to study uptake and intracellular fusion processes of endosomal/lysosomal structures.     

Goniometry for Interface Studies in Transmission Electron Microscopy

A method using a double-tilt goniometer stage for determining the orientation of crystalline specimens in transmission electron microscopy (TEM) is described. The procedure involves visual identification of two zone axes, and using the corresponding goniometer settings to plot these poles stereographically. Crystal orientations and misorientations can be established rapidly, and the method is intended for use as a practical complement to more precise but time-consuming techniques. The commutative operation of double-tilt stages and their goniometric capability are also discussed. Using Rodrigues-Frank space, it is shown that the set of attainable operations for such stages is represented by points on an hyperboloidal surface.     

Experimental IR study and ab initio modelling of ethylene adsorption in a MFI-type host zeolite

Different ab initio methods and experimental results are used to investigate the effect of the adsorption of one ethylene molecule on silicalite-1, a MFI-type zeolite. We used simplified models to simulate a portion of a straight or sinusoidal channel of silicalite-1 at a quantum level. The calculated absorption spectra of the models are qualitatively in good agreement with the experimental FTIR spectrum of silicalite-1. Additionally we simulate the FTIR spectrum of the isolated ethylene molecule and that of an ethylene molecule in interaction with the above-mentioned zeolite models. Results are discussed depending on the method and specific basis set and compared with experiments and previous molecular dynamics simulations.     

近红外光谱检测技术在聚合物领域的应用研究进展

近红外光谱(NIR)检测技术能够提供样品丰富的结构和组成信息,且具有分析速度快、样品无需处理等突出特点,在聚合物领域有了越来越广泛的应用。综述了该技术在聚合物合成到成型加工再到回收利用整个生命周期过程中各个环节的应用研究进展。在聚合物的合成和加工过程中,近红外光谱检测技术可用于材料参量的定量测量,且由于光纤良好的化学和热稳定性,使其能够在强腐蚀、高温、高压等危险环境下进行在线实时监测。对于聚合物合成,选择聚合反应转化率、聚合产物粒径和聚合物组成三个关键参量,概述了近红外光谱在线测量上述参量的相关研究进展;对于聚合物加工,主要讨论了反应性挤出加工过程中近红外光谱在线测量聚合物分子量、残余单体含量、接枝率等反映材料加工状态参量的应用研究。在聚合物的回收利用过程中,近红外光谱可用于废旧塑料制品的定性分类识别,围绕该应用分析了其国内外的研究现状。指出了近红外光谱检测技术在应用中存在的问题,并提出几点建议,最后对该技术在聚合物领域的发展方向进行了展望,并认为随着研究工作的深入和在线测量仪器的发展,近红外光谱检测技术将在聚合物领域有着更加广阔的应用前景。     

FTIR定量分析聚乙二醇/聚乙烯共混物组成

利用傅里叶转变红外光谱(FTIR)定量分析聚乙二醇/聚乙烯共混物组成,对特征谱带的选择,重叠峰的分离,数据的拟合处理作了详细讨论。采用1 378 cm-1处聚乙烯的复合峰与1 110 cm-1处聚乙二醇的复合峰强度比作为定量分析的基准,利用基于Beer-Lambert定律的理论拟合方程能较好的实现峰强度比与组分浓度的对应关系,可满足聚乙二醇/聚乙烯共混物组分的定量分析的要求。     

Electron irradiation of polyesterurethane: study of chemical and structural modifications using FTIR, UV spectroscopy and GPC

To understand the electron irradiation effects on polymers, a polyesterurethane (ESPU) was irradiated by a 200 keV electron beam perpendicular to the surface under a vacuum of 0.04 Torr with electron fluxes of 0.25–1.25×10¹³ s⁻¹ on the irradiated zone. To perform a study of ESPU degradation versus the electron's penetration depth, a stratified structure was made with seventeen 30-μm-thick films. The irradiation was performed at both room temperature (293 K) and 77 K. The applied fluence was in the range of 10¹⁴–10¹⁷ cm⁻². Chemical transformations, such as degradation and oxidation, are studied by FTIR, by following NH and OH bond evolution, and by UV spectroscopy, by following the absorbance shift towards the visible region. These effects are analyzed versus depth, fluence and electron flux. Structural transformations are also characterized by GPC for soluble samples. An increase of crosslinking rate of the polymer is observed and analyzed.     

High-resolution infrared spectroscopy of CH281BrF near 8 μm: rovibrational analysis of the ν3 and ν8 fundamentals and resonances with the dark states 2ν5 and ν6 + ν9

The infrared spectrum of isotopically enriched CH₂⁸¹BrF was investigated in the ν₃ and ν₈ region between 1150 and 1370 cm^?1 at a resolution of 0.003 cm^?1. The ν₃ vibration of symmetry species A^′ gives rise to an a-/b-hybrid band with a-type predominance, while the ν₈ mode of A^″ symmetry produces c-type absorption. Due to the proximity of the band origins to those of closely lying overtones and combination bands, the v₃ = 1 and v₈ = 1 levels were found perturbed through Coriolis resonance by the v₅ = 2 (A^′) and v₆ = v₉ = 1 (A^″) states, respectively. The spectral analysis resulted in the identification of 3132 transitions (J^″ ≤ 98 and K_a^″ ≤ 14) for the ν₃ and 2958 transitions (J^″ ≤ 68 and K_a^″ ≤ 19) for the ν₈ bands. The assigned data were fitted using the Watson's A-reduction Hamiltonian in the I^r representation and the perturbation operators. Although no transitions belonging to the perturbers were observed, the band origins and excited state parameters for fundamentals and ‘dark states’ together with coupling terms for the ν₃/2ν₅ and ν₈/ν₆ + ν₉ dyads were determined.     

New assignments in the submillimeter emission spectrum of the stratosphere

New line assignments in the spectrum of the stratospheric submillimeter emission, measured with unapodized resolution of 0.0033 cm^–1, have been made. Positive evidence for the presence of symmetric and asymmetric ozone isotopes, water vapour excited to the (010) level, and HCN is given.     

蚕豆病害叶的FTIR研究

用傅里叶变换红外光谱技术结合统计分析对蚕豆锈病、茎基腐病、轮纹病、黄化卷叶病和正常叶片进行鉴别研究。结果显示病害叶片和正常叶片的红外图谱相似,仅有几个吸收强度比存在差异;对光谱进行二阶导数分析发现,病害叶片和正常叶片的二阶导数光谱在1 200～700cm-1范围差异明显,对该区域内的光谱数据进行相关分析、主成分分析和聚类分析,结果显示,正常叶片之间、同种病害样品之间相关系数都在0.928以上,而病害叶片和正常叶片以及不同病害样品之间的相关系数降低;45个样品聚类分析和主成分分析正确率分别为73.3%和82.2%。傅里叶变换红外光谱技术具有快速、无损、准确等优点,有望为蚕豆病虫害诊断提供新的方法与途径。     

近红外光谱和聚类分析法无损快速鉴别小儿抽风散

以小儿抽风散不同缺味复方的近红外图谱作为聚类分析的对象,在建立混合成分模型的基础上,采用SIMCA聚类分析法对小儿抽风散不同缺味复方进行了快速的分类研究。实验中,在保证其他配伍组分完整的基础上,分别设缺少蜈蚣、全蝎、僵蚕、土鳖虫和蝉蜕的5个阴性样品。结果表明：尽管各样品的近红外谱图很相似,难以直接区别,但采用近红外光谱和聚类分析相结合的方法可以鉴定小儿抽风散的不同缺味复方。各样品之间光谱聚类的结果较理想,盲样检测的正确率可达90％以上。此外,如果能够获得足够多的样本,增加训练集样本数和采样的代表性,加强操作的标准程度,该法的准确率将会大大提高。因此,近红外光谱与聚类分析法相结合可以快速、无损识别中药复方。     

七种花旗参茶包的FTIR光谱法无损鉴别

本文利用傅里叶变换红外光谱法（FTIR）无损快速鉴别了七种花旗参茶包。各种花旗参茶包的红外光谱较特征。根据红外的特征谱图分析，市售的7种花旗参茶包基本上可分为两大类，一类是纯的花旗参药材料末而制成的茶包；另一类是花旗参的提取物和辅料混合后而制成的茶包。红外光谱图还表明各种花旗参茶包所选用的辅料也不尽相同，有的采用葡萄糖，有的则采用蔗糖，辅料所添加的种类与有的商品标定的不符。另外花旗参茶包所添加的辅料较多，花旗参提取物的特征峰较弱，这就表明有的花旗参茶包的质量较差。HPLC的分析结果也证明了采用原药材而制成的花旗参茶包的总皂甙含量高于花旗参的提取物和辅料混合后而制成的茶包，基本上相差了4倍。因此，红外光谱法快速、直观、可靠，适用于中药的鉴定。     

Paper Analysis: Nondestructive and Destructive Analytical Methods

Abstract: Forensic examination and dating documents is an important issue in our society, because documents are used throughout our lives to record everything we do. It starts with our birth certificate and ends with our death certificate. Between them there are receipts, leases, deeds, contracts, checks, wills, sales agreements, and medical records. The validity of all of these documents is often questioned during litigation. This study describes the use of nondestructive analysis of paper (Fourier transform infrared [FTIR] spectroscopy using an attenuated total reflectance [ATR] technique, Raman spectroscopy) and destructive analysis of paper (microscopic analysis of fibers, FTIR analysis of paper ash, inductively coupled plasma–mass spectrometry [ICP-MS]). The results are discussed in detail.