摘要 :
Mid-IR techniques were used to characterize any changes that occurred on a molecular level in flaxseed that had been heated using an autoclave. The objectives were to investigate the effects of autoclave heating on differences in ...
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Mid-IR techniques were used to characterize any changes that occurred on a molecular level in flaxseed that had been heated using an autoclave. The objectives were to investigate the effects of autoclave heating on differences in diffuse reflectance infrared Fourier transform (DRIFT) and synchrotron-based Fourier transform infrared microspectroscopy (SFTIRM) based measurements of the protein α-helix to β-sheet ratio for flaxseed (Linum usitatissimum), cv. Vimy. Hierarchical cluster analysis (CLA) and principal components analysis (PCA) were also conducted to identify molecular differences in the DRIFT spectra. Flaxseed samples were kept raw for the control or autoclaved in batches at 120°C for 20, 40 or 60 min for treatments 1, 2 and 3, respectively. DRIFT analysis of protein secondary structure ratios showed a decrease (P0.05). CLA and PCA were successfully used to make distinctions between the different treatment spectra and showed enhanced sensitivity upon selection of a smaller spectral window to include only the amide I and II portion of the IR spectrum. Our results indicated that autoclaving had a great enough effect on the mid-IR spectrum of flaxseed to identify the altered α-helix to β-sheet ratio and subsequently differentiated between the treatments using PCA and CLA suggesting greater sensitivity of mid-IR spectral methods in identifying the effect of heat treatment on protein secondary structure. Future study is needed to quantify the relationship between protein secondary structure and protein functionality.
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Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin La_(0.7)Sr_(0.3)MnO_3 with thicknesses from 3 to 70 unit cells resulted in the identification of a lower critical thickness for...
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Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin La_(0.7)Sr_(0.3)MnO_3 with thicknesses from 3 to 70 unit cells resulted in the identification of a lower critical thickness for a nonmetallic nonferromagnetic layer at the interface with the SrTiO_3 (001) substrate of only three unit cells (～ 12 A). Furthermore, linear-dichroism measurements demonstrate the presence of a preferred (x~2-y~2) in-plane orbital ordering for all layer thicknesses without any orbital reconstruction at the interface. A crucial requirement for the accurate study of these ultrathin films is a controlled growth process, offering the coexistence of layer-by-layer growth and bulklike magnetic/transport properties.
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Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at...
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Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO_3. The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features.
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Triplet enhanced ladder-type poly (para-phenylene) polymer (PhLPPP) with covalently bound trace amounts of palladium blended with a fullerene derivative [[6,6]-phenyl C_(61)-butyric acid methyl ester (PCBM)] shows power conversion...
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Triplet enhanced ladder-type poly (para-phenylene) polymer (PhLPPP) with covalently bound trace amounts of palladium blended with a fullerene derivative [[6,6]-phenyl C_(61)-butyric acid methyl ester (PCBM)] shows power conversion efficiencies (PCE) almost ten times greater than with pristine ladder-type polymer (with no palladium atom) blended with PCBM. The steady state optical properties of the triplet and nontriplet-enhanced polymers are comparable; the enhanced PCE and external quantum efficiency in PhLPPP photovoltaics are attributed to the presence of long-lived mobile triplet excitons. Furthermore, the luminescence from PhLPPP blends measured in a delayed setup correlates very well with the efficiency of the solar cells.
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We report the formation and properties of a thulium-based bulk metallic glass (BMG). Compared with other known rare-earth (RE) based BMGs, Tm-based BMGs show features of excellent glass formation ability, considerable higher elast...
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We report the formation and properties of a thulium-based bulk metallic glass (BMG). Compared with other known rare-earth (RE) based BMGs, Tm-based BMGs show features of excellent glass formation ability, considerable higher elastic modulus, smaller Poiss
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We have probed the role of La substitution on the ferroelectric properties of epitaxial BiFeO_3 films on SrTiO_3-templated Si. This provides a mechanism to engineer the rhombohedral distortion in the crystal and, thus, control dom...
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We have probed the role of La substitution on the ferroelectric properties of epitaxial BiFeO_3 films on SrTiO_3-templated Si. This provides a mechanism to engineer the rhombohedral distortion in the crystal and, thus, control domain structure and switchi
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