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981.
Fragments of wall-paintings from Roman villas in Easton Maudit, which date from ca 150 AD have been studied by Raman spectroscopy.
An intact ancient Roman paint pot discovered in the remains of a villa in Castor, Cambridgeshire, still containing a mixture
of white and red pigment was also analysed and the pigments identified as haematite and anatase. The discovery of anatase
in the intact artist’s paint pot, particularly, and also on fragments of broken paint pots from the Easton Maudit villa site,
is a unique contribution to current knowledge of ancient European pigment history, because the presence of this mineral has
not hitherto been recognised fully in an ancient artist’s palette. The relative spectral response of anatase and haematite
in the Raman data is compared with that of anatase and other red pigments such as minium, cinnabar, and litharge. 相似文献
982.
Edwards HG Mohsin MA Sadooni FN Nik Hassan NF Munshi T 《Analytical and bioanalytical chemistry》2006,385(1):46-56
The Raman spectroscopic biosignatures of halotrophic cyanobacterial extremophiles from sabkha evaporitic saltpans are reported for the first time and ideas about the possible survival strategies in operation have been
forthcoming. The biochemicals produced by the cyanobacteria which colonise the interfaces between large plates of clear selenitic
gypsum, halite, and dolomitized calcium carbonates in the centre of the salt pans are identifiably different from those which
are produced by benthic cyanobacterial mats colonising the surface of the salt pan edges in the intertidal zone. The prediction
that similar geological formations would have been present on early Mars and which could now be underlying the highly peroxidised
regolith on the surface of the planet has been confirmed by recent satellite observations from Mars orbit and by localised
traverses by robotic surface rovers. The successful adoption of miniaturised Raman spectroscopic instrumentation as part of
a scientific package for detection of extant life or biomolecular traces of extinct life on proposed future Mars missions
will depend critically on interpretation of data from terrestrial Mars analogues such as sabkhas, of which the current study is an example. 相似文献
983.
Recently, Zhou et al. [Phys. Rev. A 79 (2009) 044304] proposed a scheme for transferring three-dimensional quantum states between remote atomic qubits confined in cavities connected by fibers through adiabatic passage. In order to avoid the decoherence due to spontaneous emission, Zhou et al. utilized the large detuning atom-field interaction. In the present paper, we discuss the influence of dissipation on the scheme in both the resonant atom-field interaction case and the large detuning case. We numerically analyze the success probability and the transferring fidelity. It is shown that the resonant case is a preferable choice for the technique of the stimulated Raman adiabatic passage (STIRAP) due to the shorter operation time and the smaller probability of dissipation. 相似文献
984.
Effendi Widjaja Hui Heng Chong Martin Tjahjono 《Journal of Raman spectroscopy : JRS》2010,41(2):181-186
In situ thermo‐Raman spectroscopy (TRS) measurements were performed in order to investigate solid‐phase transformation of the copper sulfate pentahydrate from room temperature up to 300 °C. Band‐target entropy minimization (BTEM), a blind‐source separation algorithm, was employed in order to identify and reconstruct the pure component spectra of the species involved in the dehydration process. In spite of low signal‐to‐noise ratio and elevated baseline spectral data, BTEM was successfully utilized to identify and reconstruct four pure component spectra of copper sulfate pentahydrate, trihydrate, monohydrate, and anhydrate, which were formed during this thermally induced process. Subsequent mapping of these four pure component spectral estimates back onto the preprocessed spectra yielded the relative concentrations of each individual species. Finally, the transition temperatures of each dehydration step could be unambiguously deduced from the obtained concentration profile. The current study shows that combined thermo‐Raman spectroscopy and chemometric analysis provides an effective tool to determine the dehydration temperatures as well as to identify the structures of each individual species involved in a solid‐phase dehydration process. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
985.
Surface‐enhanced Raman scattering and density functional theory studies of bis(4‐aminophenyl)sulfone
Guillermo Diaz‐Fleming Freddy Clis Carlos Fredes Marcelo Campos‐Vallette Alvaro E. Aliaga Rainer Koch 《Journal of Raman spectroscopy : JRS》2010,41(2):160-166
Raman and surface‐enhanced Raman scattering (SERS) spectra of dapsone by using colloidal silver nanoparticles have been recorded. Density functional theory was used for the optimization of ground state geometries and simulation of the vibrational spectrum of this molecule. The SERS spectrum with a large silver cluster as a model metallic surface was simulated for the first time. Taking into account the experimental and calculated Raman as well as the SERS normal modes and the corresponding assignments, along with the modeling of the free dapsone and the one in the presence of the colloidal silver nanoparticles, the importance of the sulfone group on the SERS effect in dapsone was inferred. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
986.
Pu‐Jun Jin Zheng‐Quan Yao Mao‐Lin Zhang Yu‐Hu Li Hui‐Ping Xing 《Journal of Raman spectroscopy : JRS》2010,41(2):222-225
A blue pigment was identified by micro‐Raman spectroscopy, X‐ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM)/energy dispersive X‐ray (EDX) and X‐ray diffraction (XRD). The test sample, a funerary lacquer tray, belongs to West Han Dynasty (206 BC–AD 8) of China and was decorated with faint blue patterns. The result from Raman spectroscopy showed that the faint blue is covellite (CuS) due to the presence of a characteristic peak at 474.5 cm−1, which further was confirmed by XRF, SEM–EDX and XRD. This research indicated that CuS had been used as a blue pigment to decorate lacquer wares from the West Han Dynasty in China. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
987.
Raman spectroscopy has been used to characterize the antimonate mineral bahianite Al5Sb35+O14(OH)2, a semi‐precious gemstone. The mineral is characterized by an intense Raman band at 818 cm−1 assigned to Sb3O1413− stretching vibrations. Other lower intensity bands at 843 and 856 cm−1 are also assigned to this vibration, and this concept suggests the non‐equivalence of SbO units in the structure. Low‐intensity Raman bands at 669 and 682 cm−1 are probably assignable to the OSbO antisymmetric stretching vibrations. Raman bands at 1756, 1808 and 1929 cm−1 may be assigned to δ SbOH deformation modes, while the bands at 3462 and 3495 cm−1 are assigned to AlOH stretching vibrations. The complexity in the low wave number region is attributed to the composition of the mineral. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
988.
Mehmet Karabacak Mehmet Cinar Sahin Ermec Mustafa Kurt 《Journal of Raman spectroscopy : JRS》2010,41(1):98-105
In this work, the Fourier transform infrared and Raman spectra of 2‐bromonicotinic acid and 6‐bromonicotinic acid (abbreviated as 2‐BrNA and 6‐BrNA, C6H4BrNO2) have been recorded in the region 4000–400 and 3500–50 cm−1. The optimum molecular geometry, normal mode wavenumbers, infrared intensities and Raman scattering activities, corresponding vibrational assignments and intermolecular hydrogen bonds were investigated with the help of B3LYP density functional theory (DFT) method using 6‐311++G(d,p) basis set. Reliable vibrational assignments were made on the basis of total energy distribution (TED) calculated with scaled quantum mechanical (SQM) method. From the calculations, the molecules are predicted to exist predominantly as the C1 conformer. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
989.
Caterina Rinaudo Mario Allegrina Elisa Fornero Maya Musa Alessandro Croce Donata Bellis 《Journal of Raman spectroscopy : JRS》2010,41(1):27-32
Histological sections of a patient affected by an important respiratory disease were analysed firstly by optical microscope(OM)—crossed polarisers—to identify the presence of incorporated inorganic particles, with particular attention to the fibrous ones. Then, the particles/fibres that were found were studied both with micro‐Raman spectroscopy and variable‐pressure scanning electron microscopy with energy‐dispersive spectroscopy (VP‐SEM/EDS). The two techniques allowed the in situ characterisation of the inorganic phases without disintegration of the organic matter. Micro‐Raman spectroscopy was able to identify the vibrating chemical groups of the mineral phase associated with the inorganic grain while the crystalline structure was preserved by the biological system. The VP‐SEM/EDS characterisation, defining the elemental chemical composition of the analysed particle/fibre, allowed confirmation of the mineral phase deducible from spectroscopic data or its identification with certainty when the spectroscopic data were not exhaustive. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
990.
Zhihao Geng 《Physics letters. A》2010,375(2):214-219
The doping and temperature dependence of the electronic Raman response in cuprate superconductors is studied within the kinetic energy driven superconducting mechanism. It is shown that the temperature dependent depletion at low-energy shifts is faster in the B1g symmetry than in the B2g symmetry. In analogy to the domelike shape of the doping dependent superconducting transition temperature, the maximal peak energy in the B2g channel occurs around the optimal doping, and then decreases in both underdoped and overdoped regimes. Moreover, the overall density of Cooper pairs increases with increasing doping in the underdoped regime. 相似文献