Abstrat Water molecules in the vicinity of polymers influence the behaviors of solvated polymeric materials. However, understanding the behavior of these vicinal water molecules is challenging. Using a multivariate curve resolution (MCR) approach, we present a method for extracting the infrared absorption spectra of vicinal water of poly(N-isopropylacrylamide) (PNIPAAm). Our analysis successfully quantified vicinal water molecules, showing significantly higher hydration numbers in the hydrophilic state, providing insights into the role of vicinal water in the temperature-dependent affinity switching of PNIPAAm towards cells.
We report total internal reflection fluorescence microscopy (TIRFM) measurements using an atomic force microscope (AFM) probe to investigate the quantitative fluorescence profiles of CdSe/ZnS nanocrystals (NCs), which interact with gold surfaces, as a function of the gold–NC distance. First, a silica bead was glued to an AFM cantilever. CdSe/ZnS NCs were then immobilized on the silica-bead-functionalized AFM probe for control of the gold–NC distance, while a gold thin film served as the metal surface on a glass substrate. As a result of coexistent fluorescence resonance energy transfer and localized surface plasmon resonance (LSPR) coupling, a strong enhancement was observed at 15 nm, while fluorescence suppression was seen at a proximal distance. For further quantitative discussions of the effects of the metal surface on the fluorescence behavior of single NCs, we introduced a gold-deposited silica bead onto the AFM cantilever to regulate the gold–NC distance. Subsequently, the CdSe/ZnS NCs were immobilized on a glass surface. As a result of compensation for the contribution of photobrightening, the NC fluorescence profile for the glass surface also clearly displayed the LSPR-coupled enhancement at 10 nm. In contrast, it was discovered that positioning of the gold surface at a proximal single NC gave rise to quenching of the NC fluorescence. Our findings suggest that a method using an NC-functionalized AFM probe allows us to quantitatively investigate the NC fluorescence under the effects not only of a metal surface but also of an evanescence field.
A large oil-free reciprocating pump was developed for high level tritium service. The pump is a water-cooled, single acting, four stage vertical piston vacuum pump. The characteristics of the pump were measured with H2, D2, He and N2 gases. Pumping speeds were approximately 180 M3/hr for these gases and almost constant above 10 torr of suction pressure., while it drastically dropped in the lower pressure region. The pump combination with a magnetic levitated turbomolecular pump worked well with N2, however He, D2 and H2 could not be pumped well due to poor matching of the characteristics of these pumps.
Fluorine atoms are selectively attached to the sidewall of the outer shell of DWNTs without disrupting the double-layered morphology; the stoichiometry of the fluorinated DWNTs is CF(0.30).
Abstract : Properties of magnetic islands induced by the finite pressure effect are numerically analyzed for three-dimensional magnetohydrostatic equilibria of Helias and l = 2 heliotron/torsatron types. For Helias, it is found that an island chain is generated on the 5/6 rational surface, when such a surface appears in the plasma region of a finite-B equilibrium. The island chain, however, is not so dangerous as to destroy the plasma confinement even if it appears in a vanishingly small shear region. Moreover, it is definitely confirmed that the finite pressure effect sometimes exhibits a surprisingly good aspect, namely, that the vacuum islands are removed as B increases, which can be called 'self-healing' of islands. This property can be explained by the numerically discovered fact that the phases of islands induced by the finite pressure effect are always locked i.e. do not change regardless of B. The way islands appear at finite-B for heliotron/torsatron is significantly different from that for Helias. However, we find the self-healing of islands can also occur for the heliotron configuration. This phenomenon can partly explain the reason why the fragility of surfaces decreases when they are shifted inward by control of the external vertical field Bv, though the configuration develops a magnetic hill. Furthermore, we analyze the diversion properties of the magnetic field outside the last closed magnetic surface for finite-B equilibria, and find that divertor concepts which have been developed from the diversion properties of the corresponding vacuum fields can be maintained for finite-B equilibria for both configurations.
H2O2treatment can decrease the electrical resistivity of double walled carbon nanotube fibers. The experimental observations suggest that small diameter carbon nanotubes are removed from the fiber sample.
Scanning probe microscopy (SPM) is a powerful method for visualizing the structure of materials at the nanoscale.In particular, atomic force microscopy (AFM) has become one of the most used analytical tools in various fields such as physics, chemistry, and biology.Here, we introduce representative works in nano-bioscience.First, we look back on the history of SPM and introduce the application of AFM in this field.Next, we review surface force and singlemolecule force measurements, which unveiled molecular processes at biointerfaces.Surface force measurements revealed the mechanism underlying the macroscopically observed protein and cell resistance of artificial monolayers and biomolecules.Meanwhile, single-molecule force spectroscopy has enabled researchers to explore the complex interaction of biomolecules from a microscopic viewpoint.These findings will contribute not only to the fundamental understanding of biomolecular processes but also to the design of new nano-biodevices.
