Spectroscopic and Computational Insight into the Intermolecular Interactions between Zwitter‐Type Ionic Liquids and Water Molecules

Geometric and conformational changes of zwitter‐type ionic liquids (ZILs) due to hydrogen‐bonding interactions with water molecules are investigated by density functional theory (DFT), two‐dimensional IR correlation spectroscopy (2D IR COS), and pulsed‐gradient spin‐echo NMR (PGSE NMR). Simulation results indicate that molecular structures in the optimized states are strongly influenced by hydrogen bonding of water molecules with the sulfonate group or imidazolium and pyrrolidinium rings of 3‐(1‐methyl‐3‐imidazolio)propanesulfonate ( 1 ) and 3‐(1‐methyl‐1‐pyrrolidinio)propanesulfonate ( 2 ), respectively. Concentration‐dependent 2D IR COS reveals kinetic conformational changes of the two ZIL–H₂O systems attributable to intermolecular interactions, as well as the interactions of sulfonate groups and imidazolium or pyrrolidinium rings with water molecules. The dramatic changes in the ¹H self‐diffusion coefficients elucidate the formation of proton‐conduction pathways consisting of ZIL networks. In ZIL domains, protons are transferred by a Grotthuss‐type mechanism through formation, breaking, and restructuring of bonds between ZILs and H₂O, leading to an energetically favorable state. The simulation and experimental investigations delineated herein provide a perspective to understanding the interactions with water from an academic point of view as well as to designing ILs with desired properties from the viewpoint of applications.     

Synthesis of aqueous dispersion of graphenes via reduction of graphite oxide in the solution of conductive polymer

Graphene sheets were produced by chemical reduction of graphite oxides in the solution of ionic conductive polymer, Nafion. The obtained graphene, coated with Nafion, can be re-dispersed in water, and readily forms stable dispersed state. The polymer-coated graphene had been characterized by FT-IR spectroscopy, UV-vis and X-ray photoelectron spectroscopy (XPS). The PEDOT film with Nafion-coated graphene increased significantly from 0.25 S/cm for pure PEDOT film and reached 12 S/cm. Further, the films of PEDOT doped Nafion-coated graphene had also higher conductivities compared to films doped PSS-coated graphene.     

Regional Absolute Quantification of the Neurochemical Profile of the Canine Brain: Investigation by Proton Nuclear Magnetic Resonance Spectroscopy and Tissue Extraction

The purpose of this study was to characterize the neurochemical profiles of various parts of the canine brain using proton nuclear magnetic resonance spectroscopy, tissue extraction, and external simulated phantom concentration quantification. The occipital, frontal, and temporal lobes, thalami, cerebellar cortices, and spinal cords of five pure bred adult beagles were collected, and heavy water solutions for the nuclear magnetic resonance sample were prepared using the methanol–chloroform–water extraction method. The metabolite concentrations in canine brain tissues were measured and compared with those found in human and rat brain tissues. In addition, the cross peaks of Lac, Glu/Gln, and mIns were identified using two-dimensional correlation spectroscopy in the canine frontal cortex. The present study demonstrated the absolute quantification of canine neuronal parts using in vitro high-resolution magnetic resonance spectroscopy, with tissue extraction used to accurately measure metabolite concentrations, thus providing valuable metabolic information regarding the various canine neuronal regions.     

Laser-induced acoustic wave generation/propagation/interaction in water in various internal channels

Short pulsed laser-induced single acoustic wave generation, propagation, interaction within a water-filled internal channel are experimentally and numerically studied. A large-area, short-duration, single-plane acoustic wave was generated by the thermoelastic interaction of a homogenized nanosecond pulsed laser beam with a liquid–solid interface and propagated at the speed of sound in water. Laser flash Schlieren photography was used to visualize the transient interaction of the plane acoustic wave in various internal channel structures ((a) sudden expansion and contraction channels, (b) bifurcating channels, (c) gradual contraction wall channels and (d) a cylinder). Fairly good agreement between the experimental results and numerical simulation is observed.     

Vibration frequency and lock-in bandwidth of tensioned,flexible cylinders experiencing vortex shedding

In-water vortex-induced vibration (VIV) tests of top-tensioned, flexible cylindrical structures were conducted at Shell Westhollow Technology Center current tank. These tests revealed that the top tension and structural stiffness (both lateral and axial) can have a significant impact on vibration frequencies. During lock-in between the vortex-shedding frequency and the structure's natural frequency, the increase of the vibration frequency with flow speeds is strongly related to the rise of the axial tension. After an initial abrupt rise, the vibration frequency of a bending-stiffness-dominated structure only increased slightly during lock-in. Alternative explanations are provided on why the vibration frequency does not rise significantly but there can still exist a broad lock-in band, and why a more massive structure has a narrower lock-in bandwidth.     

The formation of sub-10 nm nanohole array on block copolymer thin films on gold surface using surface neutralization based on O2 plasma treatment and self-assembled monolayer

Blockcopolymer (BCP) lithography is an emerging nanolithography technique for fabrications of various nanoscale devices and materials. In this study, self-assembled BCP thin films having cylindrical nanoholes were prepared on gold by surface neutralization using self-assembled monolayer (SAM). Oxygen plasma treatment was investigated as a way to enhance the functionality of Au surface toward SAM formation. After surface neutralization, well-ordered nanoholes with 9 to 20 nm diameters were formed inside BCP thin films on Au surfaces through microphase separation. The effects of oxygen plasma treatment on the formation of BCP nanopattern were investigated using surface analysis techniques including X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. Au nanodot arrays were fabricated on gold film by utilizing the BCP nanotemplate and investigated by atomic force microscopy (AFM).     

Half-metallicity at the non-polar surfaces of rock-salt and zinc-blende MgN

We discuss the electronic properties of non-polar surfaces of MgN rock-salt and zinc-blende crystals. We studied the (001) surface of the rock-salt and the (110) surface of the zinc-blende MgN with the use of an ab initio full-electron linearized augmented plane wave method within density functional theory. The structural parameters of the two surfaces were optimized by relaxing the position of the atoms in the unit cells in the force directions. The results of the calculations indicate that both rock-salt MgN (001) and ZB MgN (110) demonstrate half-metallic properties. The zinc-blende MgN (110) surface is electronically more stable as a half-metal than the rock-salt MgN (001) surface. The magnetic properties of the two systems are tailored mainly by the spin-polarization of electrons of N atoms.     

Chemical and physical characteristics of self-fabricated radiophotoluminescent glass dosimeter

Thermoluminescent dosimeters are widely applied in the measurement of radiation dose. Since the luminescent centers are not lost during the reading process, radiophotoluminescent glass dosimeters (RPLGDs) can be repeatedly readout. The aims of this study were to make RPLGD and to analyze its physical and chemical properties. This study used chemical compounds such as Na₃PO₄, AlPO₄, AgCl, AgNO₃, B₂O₃, H₃PO₄ and P₂O₅ as the main ingredients. Depending on the self-fabricated glass compounds, the melting temperatures were between 1100 and 1500 °C. When the 0.1 mol% of silver was added, the radiation detection of self-fabricated RPLGD reached to the highest sensitivity. However, when silver concentration was larger than 0.1 mol%, the radiation detection sensitivity plummets rapidly. Excess amounts of silver and aluminum decreased the penetrate capability of ultraviolet spectrum. Based on our study, we found that chemical compound concentrations and melting process, which all affect radiation sensitivity and stability of self-fabricated RPLGD.     

Rapid decolorization of azo dyes in aqueous solution by an ultrasound-assisted electrocatalytic oxidation process

In this study, we developed a novel ultrasound-assisted electrocatalytic oxidation (US–EO) process to decolorize azo dyes in aqueous solution. Rhodamine B was decolorized completely within several minutes in this developed US–EO system. Oxidation parameters such as applied potentials, power of the ultrasound, initial pH of the solution, and initial concentration of RhB were systematically studied and optimized. An obvious synergistic effect was found in decolorization of RhB by the US–EO process when comparing with either ultrasound (US) process or electrocatalytic oxidation (EO) one. Additionally, the decolorization of other azo dyes, such as methylene blue, reactive brilliant red X-3B, and methyl orange, were also effective in the US–EO system. The results indicated that US–EO system was effective for the decolorization of azo dyes, suggesting its great potential in dyeing wastewater treatment.