EFFICIENT ELECTROCHEMICAL FUNCTIONALIZATION OF CARBON NANOTUBES AND CARBON NANOTUBE MEMBRANES FOR ENERGY, DRUG DELIVERY AND POTENTIAL CATALYSIS APPLICATIONS

Electrochemical diazonium grafting offers versatile functionalization of chemically inert graphite under mild condition, which is particularly suitable for CNT composite modification. Tetrafluorinated carboxylphenyl diazonium grafting provides the most controllable functionalization chemistry allowing near monolayer levels of functionality on carbon nanotubes. The functional density was successfully quantified by anion selective dye-assay and X-ray photoelectron spectroscopy (XPS) of thiol-Au self-assembled monolayers (SAM) as a calibration reference. This technique enables monolayer functionality at the tips of carbon nanotube membranes for biomimetic pumps and valves as well as thin conductive layers for CNT-based high area electrochemical support electrodes. Double-walled carbon nanotube (DWCNT) membranes were functionalized with sterically bulky dye molecules with amine termination in a single step functionalization process. Non-faradic (EIS) spectra indicated that the functionalized gatekeeper by single-step modification can be actuated to mimic protein channel under bias. This functional chemistry on membranes resulted in rectification factors of up to 14.4 with potassium ferricyanide in trans-membrane electrochemical measurements. One step functionalization by electrooxidation of amines provides simple and promising functionalization chemistry for the application of CNT membranes. Carbon nanotubes (CNTs) are considered a promising catalyst support due to high surface area, conductivity and stability. But very few cases of asymmetric catalysis have been reported using CNTs as support. Three noncovalent functionalization approaches have been carried out to immobilize Rh-Josiphos complex on CNTs for asymmetric hydrogenation of dimethyl itaconate. Coordinated Rh catalyst on CNTs exhibited excellent activity and reuse ability even after seventh run in hydrogenation but no enantiomeric excess as expected for lacking a chiral directing ligand. The catalyst using pyrene absorption gave 100% yield and excellent enantiomer excess (\u3e90%) but suffered from leaching into solution. The phosphotungstic acid (PTA) anchored catalyst gave 100% yield and higher ee (99%) and better reusability over pyrene absorbed catalyst but had significant leaching after the second run. At this point it remains a significant challenge to utilize CNTs as a chiral catalyst support

Paleoenvironment and paleoclimate of NE Pangea in early Permian-linking chemo- and cyclo-stratigraphy, Bogda Mountains, NW China

The overall objective of this study is to understand physical and chemical responses of Earth Systems to environmental and climatic perturbations of diverse magnitudes and time scales in Bogda Mountains, NE Pangea. Field investigations, petrographic observations, and geochemical analyses have been used to interpret paleoenvironment and paleoclimate in cm-m-scale high-order cycles (HCs: 0.1-100 kyrs), low-order cycles (LCs: 1-10 Myr), and critical events of late Paleozoic ice age (LPIA: 320-260 Myr ago). Four organo-facies are one-to-one correlated with the four lithofacies in the meter-scale HCs, suggesting litho- and organo-facies are genetically linked and fundamentally controlled by environmental changes associated with lake contraction and extension. The coincidence of climatic changes in mid-latitude northeast Pangea and Gondwanan glacial-interglacial in mid Sakmarian-early Kungurian provides clues that glaciation may have exerted a substantial control on climatic changes in mid-latitude Northern Hemisphere --Abstract, page iv

Bolt Detection Signal Analysis Method Based on ICEEMD

The construction quality of the bolt is directly related to the safety of the project, and as such, it must be tested. In this paper, the improved complete ensemble empirical mode decomposition (ICEEMD) method is introduced to the bolt detection signal analysis. The ICEEMD is used in order to decompose the anchor detection signal according to the approximate entropy of each intrinsic mode function (IMF). The noise of the IMFs is eliminated by the wavelet soft threshold de-noising technique. Based on the approximate entropy, and the wavelet de-noising principle, the ICEEMD-De anchor signal analysis method is proposed. From the analysis of the vibration analog signal, as well as the bolt detection signal, the result shows that the ICEEMD-De method is capable of correctly separating the different IMFs under noisy conditions, and also that the IMF can effectively identify the reflection signal of the end of the bolt