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Synthesis of plasmonic Fe/Al nanoparticles in ionic liquids
摘要： Bottom-up and top-down approaches are described for the challenging synthesis of Fe/Al nanoparticles (NPs) in ionic liquids (ILs) under mild conditions. The crystalline phase and morphology of the metal nanoparticles synthesized in three different ionic liquids were identified by powder X-ray diffractometry (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected-area electron diffraction (SAED) and fast Fourier transform (FFT) of high-resolution TEM images. Characterization was completed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) for the analysis of the element composition of the whole sample consisting of the NPs and the amorphous background. The bottom-up approaches resulted in crystalline FeAl NPs on an amorphous background. The top-down approach revealed small NPs and could be identified as Fe4Al13 NPs which in the IL [OPy][NTf2] yield two absorption bands in the green-blue to green spectral region at 475 and 520 nm which give rise to a complementary red color, akin to appropriate Au NPs.
关键词： plasmonic properties,bottom-up synthesis,ionic liquids,Fe/Al nanoparticles,top-down synthesis
更新于2025-09-23 15:21:01
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Rating the Intensity of a Laser Stimulus, but Not Attending to Changes in Its Location or Intensity Modulates the Laser-Evoked Cortical Activity
摘要： Top-down attention towards nociceptive stimuli can be modulated by asking participants to pay attention to specific features of a stimulus, or to provide a rating about its intensity/unpleasantness. Whether and how these different top-down processes may lead to different modulations of the cortical response to nociceptive stimuli remains an open question. We recorded electroencephalographic (EEG) responses to brief nociceptive laser stimuli in 24 healthy participants while they performed a task in which they had to compare two subsequent stimuli on their Spatial location (Location task) or Intensity (Intensity Task). In two additional blocks (Location + Ratings, and Intensity + Ratings) participants had to further provide a rating of the perceived intensity of the stimulus. Such a design allowed us to investigate whether focusing on spatial or intensity features of a nociceptive stimulus and rating its intensity would exert different effects on the EEG responses. We did not find statistical evidence for an effect on the signal while participants were focusing on different features of the signal. We only observed a significant cluster difference in frontoparietal leads at approximately 300–500 ms post-stimulus between the magnitude of the signal in the Intensity and Intensity + Rating conditions, with a less negative response in the Intensity + Rating condition in frontal electrodes, and a less positive amplitude in parietal leads. We speculatively propose that activity in those electrodes and time window reflects magnitude estimation processes. Moreover, the smaller frontal amplitude in the Intensity + Rating condition can be explained by greater working memory engagement known to reduce the magnitude of the EEG signal. We conclude that different top-down attentional processes modulate responses to nociceptive laser stimuli at different electrodes and time windows depending on the underlying processes that are engaged.
关键词： top-down modulation,pain,ratings,attention,EEG,laser evoked potentials (LEPs)
更新于2025-09-23 15:19:57
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Top-down Fabrication of Colloidal Plasmonic MoO <sub/>3-x</sub> Nanocrystals via Solution Chemistry Hydrogenation
摘要： A high-efficiency top-down approach was used to fabricate orthorhombic MoO3-x nanocrystals through the synergic effect of oleic acid (OA) and oleylamine (OAm), in which OA providing H+ ions and OAm contributing free electrons. This investigation might provide new guidance for manipulating the optical properties of metal oxide semiconductors.
关键词： top-down fabrication,solution chemistry hydrogenation,oleic acid,oleylamine,colloidal plasmonic MoO3-x nanocrystals
更新于2025-09-23 15:19:57
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Nano-Scaled Lanthanum Hexaboride (LaB6) – Control of Properties in Dependence on Type of Manufacturing
摘要： This paper presents the influence of fabrication methods on the optical and photo-thermal properties of nano-LaB6. The nano particles (NPs) were manufactured via continuously operated ball milling or induction plasma technology. Whereas different grinding processes for LaB6 were also discussed using ethylene glycol (EG) and ZrO2 grinding media in previous works, the scaled-up plasma technology presents a new possibility to gain NPs with high yields and narrow size distribution. In our work, NPs < 100 nm are achieved by grinding experiments using ethanol, 1-methoxy-2-propanol and ethylene glycol. Furthermore, the change of grinding parameters was investigated intensively. Compared to milled NPs, nano-LaB6 in high purity are gained by plasma technology and shows differences in color, morphology (UHR-FESEM), absorption behavior and crystallite size (X-Ray). Acrylate terminated starPEG (poly ethylene glycol) was used as a high cross-linked network after in-situ UV polymerization to stabilize NPs homogenously. We also set the focus on photo-thermal conversion properties of LaB6 dispersions in ethylene glycol, i.e. transformation of the absorbed photon energy into heat, and temperature distribution around the laser spot which are characterized by an IR camera.
关键词： photo-thermal conversion,top-down,ball milling LaB6,LaB6 nano particles,SPR,plasma LaB6,LaB6 stabilization
更新于2025-09-16 10:30:52