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表面增强拉曼光谱(SERS)技术广泛应用于表面/界面科学、光谱学、生化检测、成像示踪等领域。金属烯碳纳米囊是一类由烯碳壳层包裹金属核组成的核壳纳米颗粒,由于金属烯碳纳米囊具有高SERS灵敏度,在复杂和极端的生化环境下优异的稳定性和光学性质,因此在生化检测分析和成像示踪等领域备受关注。超薄烯碳壳层固有的化学惰性可以保护金属内核免受光生热电子、活性氧以及酶等外部因素的破坏,从而使金属烯碳纳米囊展现出超稳定的拉曼信号。此外,烯碳壳层的多个拉曼特征峰位(D、G、2D)可作为拉曼信号和内标信号,进一步提高了拉曼定量检测的准确度。值得注意的是2D峰作为拉曼静默区域内的信号峰有利于减少体内生物分子的干扰。本文首先介绍了金属烯碳纳米囊的制备原理和基本性质,概述了基于金属烯碳纳米囊的SERS检测和成像中的应用进展,最后展望了金属烯碳纳米囊在疾病诊疗的前景和潜力。 相似文献
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报道了阿莫西林对照品与阿莫西林胶囊的常规拉曼光谱(NRS)和在银胶基底上溶液的表面增强拉曼光谱(SERS),归属了各个振动峰位和增强峰位;研究了阿莫西林对照品溶液与DNA相互作用的荧光光谱和表面增强拉曼光谱.结果表明:阿莫西林胶囊与阿莫西林对照品的NRS及SERS图谱基本一致,说明胶囊中的辅料对阿莫西林的检测几乎没有影... 相似文献
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《中国物理快报》2016,(4)
Regulation of optical properties and electronic structure of two-dimensional layered ReS_2 materials has attracted much attention due to their potential in electronic devices.However,the identification of structure transformation of monolayer ReS_2 induced by strain is greatly lacking.In this work,the Raman spectra of monolayer ReS_2 with external strain are determined theoretically based on the density function theory.Due to the lower structural symmetry,deformation induced by external strain can only regulate the Raman mode intensity but cannot lead to Raman mode shifts.Our calculations suggest that structural deformation induced by external strain can be identified by Raman scattering. 相似文献
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Structural deformation of nitro group of nitromethane molecule in liquid phase in an intense femtosecond laser field 下载免费PDF全文
The structural deformation of NO_2 group induced by an intense femtosecond laser field of liquid nitromethane(NM)molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy(CARS) technique with the intense pump laser. Here, we present the mechanism of molecular alignment and deformation. The CARS spectra and its FFT spectra of liquid NM show that the NO_2 torsional mode couples with the CN symmetric stretching mode and that the NO_2 group undergoes ultrafast structural deformation with a relaxation time of 195 fs. The frequency of the NO_2 torsional mode in liquid NM(50.8±0.3 cm~(-1)) at room temperature is found. Our results prove the structural deformation of two groups in liquid NM molecule occur simultaneously in the intense laser field. 相似文献
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Tracking molecular structure deformation of nitrobenzene and its torsion-vibration coupling by intense pumping CARS 下载免费PDF全文
The structural deformation induced by intense laser field of liquid nitrobenzene(NB) molecule,a typical molecule with restricting internal rotation,is tracked by time- and frequency-resolved coherent anti-Stokes.Raman spectroscopy(CARS) technique with an intense pump laser.The CARS spectra of liquid NB show that the NO_2 torsional mode couples with the NO_2 symmetric stretching mode,and the NB molecule undergoes ultrafast structural deformation with a relaxation time of 265 fs.The frequency of NO_2 torsional mode in liquid NB(42 cm~(-1)) at room temperature is found from the sum and difference combination bands involving the NO_2 symmetric stretching mode and torsional mode in time- and frequency-resolved CARS spectra. 相似文献
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通过结合纳米压痕和偏振拉曼散射技术对压应力影响下ZnO单晶晶格出现的变化进行了研究。位错的滑移是导致ZnO单晶中出现多处塑性变形的原因而非相变。之后采用偏振拉曼Mapping成像技术以E2(high)模为对象, 监视其在整个压痕区内的强度变化分布。在压痕区中心累积的应力通过位错的滑移而释放, 同时导致压痕区中心处的晶格畸变程度最为严重。伴随着晶格失配的加剧, 拉曼选择定则放宽, 在Z(XX)配置下较弱的LO得到增强, 原本非拉曼活性的B1(high)模出现。此外, 在Z(XY)偏振下压痕区左侧的拉曼光谱中观察到位于130 cm-1处的拉曼异常振动模。此峰的出现可能与压痕区左侧由刃位错所形成的应力场吸引间隙离子导致的晶格畸变有关。 相似文献
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P. Rovillain A. Sacuto D. Colson 《Journal of magnetism and magnetic materials》2009,321(11):1699-1701
The piezoelectric response of BiFeO3 at low temperature has been investigated by Raman scattering measurements. The application of an external electric field at T=10 K induces frequency shifts of the lowest frequency mode related to the Bi-O bonds and corresponding to the soft mode of the ferroelectric transition. The piezoelectric effect is responsible for the softening of this mode via the tensile stress leading to the expansion of the crystal. The phonon deformation potential associated with the soft mode has been estimated around −200 cm−1/strain units using the linear piezoelectric coefficient d33=16 pm/V. It found in the range of the ones obtained for typical piezoelectrics. 相似文献
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为了探讨不同变质程度煤在不同变形机制和变形强度影响下的结构成分演化,该文对淮北煤田经历不同变质变形作用的构造煤样品进行了傅里叶变换红外光谱(FTIR)和激光Raman光谱的测试和分析.FTIR显示,变质和变形作用对大分子结构的降解和缩聚过程有着不同程度的影响;激光Raman光谱显示,变形作用导致大分子结构中次生结构缺陷的产生,变质作用对次生结构缺陷和芳族总量也有一定的影响.综合研究表明:韧性变形将应力作用转换成应变能,对降解和缩聚产生明显的影响,而脆性变形将应力作用转换成热能,促进降解的进行,对缩聚作用的影响较小.低变质阶段煤岩以降解作用为主,高变质阶段则以缩聚作用为主.在变质变形作用的影响下,脱落的小分子优先补充嵌入大分子结构的次生结构缺陷中或残留的芳环缩聚形成芳族结构,从而提高煤岩结构的稳定性,且韧性变形比脆性变形更容易导致次生结构缺陷的形成. 相似文献
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在5K~300K温度范围内对六氯铅铵晶体进行了拉曼散射测量,该晶体在Tc=78K发生从立方结构(O^54)至三方结构(C^23i)的二级相变,PbCl^2-6八面体A1g模和NH^+4四面体A1模的拉曼频移在Tc时出现极大值,八面体T2g模,四面体T2模和外振动T2g模在Tc以下发生连续分裂,另外在Tc以下观测到对应于高温相PbCl^2-6八面体T1g模的软模。 相似文献
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Stresses induced by welding are analyzed from the viewpoint of material deformation behavior. Strain gages are used to measure the residual stresses, and electronic speckle-pattern interferometry is used to analyze the response of the welded work to external force. A tensile load is applied to a butt-welded, thin-plate steel specimen, and the resultant strain field is analyzed with the electronic speckle-pattern interferometry. Comparison is made with the case of a nonwelded specimen of the same material and dimension. The analysis indicates that the residual stress due to welding makes the normal strain due to the external tensile load asymmetric. The asymmetry enhances shear and rotational modes of deformation, generating stress concentration at a point away from the weld where the residual stress is substantially negligible. The observed features are discussed based on physical mesomechanics. Analysis reveals plastic deformation like behavior in the response of the welded specimen to the external force. 相似文献
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通过交流磁化率、电阻、有无磁场下的预相变应变、磁致伸缩和磁化强度测量,系统研究了近正配分比Ni505Mn245Ga25单晶的预马氏体相变特性.在自由样品中观察到预马氏体相变应变.在预相变点,沿[010]方向施加大小约为80kA/m的磁场,在晶体母相的[001]方向上获得了高达505ppm的磁致伸缩,该值是相同条件下晶体母相磁致伸缩量的5倍多.同时,报道了不同方向磁场对预相变应变干预的结果.利用软模凝结的概念和依据单晶生长的特点,分析了预相变应变产生的机理.而磁场干预预相变应变的机理是磁场增大的磁弹耦合导致的晶格形变与材料内禀形变的竞争.利用磁性测量结果证实和解释了预相变过程中[001]和[010]轴方向间进一步增大的各向异性.进而对磁场沿[001]和[010]两个晶体学方向所导致的应变特性的差别,包括最大磁致伸缩、饱和预相变应变、饱和场等,进行了分析和讨论.
关键词:
预马氏体相变
应变
磁致伸缩
磁弹耦合 相似文献