Search results for " Multidisciplinary"
showing 10 items of 209 documents
Ligand engineering in Cu(ii) paddle wheel metal–organic frameworks for enhanced semiconductivity
2020
We report the electronic structure of two metal-organic frameworks (MOFs) with copper paddle wheel nodes connected by a N2(C2H4)3 (DABCO) ligand with accessible nitrogen lone pairs. The coordination is predicted, from first-principles density functional theory, to enable electronic pathways that could facilitate charge carrier mobility. Calculated frontier crystal orbitals indicate extended electronic communication in DMOF-1, but not in MOF-649. This feature is confirmed by bandstructure calculations and effective masses of the valence band egde. We explain the origin of the frontier orbitals of both MOFs based on the energy and symmetry alignment of the underlying building blocks. The effe…
Interfacial Self-Assembly to Spatially Organize Graphene Oxide Into Hierarchical and Bioactive Structures
2020
Multicomponent self-assembly holds great promise for the generation of complex and functional biomaterials with hierarchical microstructure. Here, we describe the use of supramolecular co-assembly between an elastin-like recombinamer (ELR5) and a peptide amphiphile (PA) to organize graphene oxide (GO) flakes into bioactive structures across multiple scales. The process takes advantage of a reaction—diffusion mechanism to enable the incorporation and spatial organization of GO within multiple ELR5/PA layers. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ImageJ software were used to demonstrate the hierarchical organization of GO flakes within the ELR5/PA lay…
Ultrathin Films of 2D Hofmann-Type Coordination Polymers: Influence of Pillaring Linkers on Structural Flexibility and Vertical Charge Transport
2019
Searching for novel materials and controlling their nanostructuration into electronic devices is a challenging task ahead of chemists and chemical engineers. Even more so when this new application requires an exquisite control over the morphology, crystallinity, roughness and orientation of the films produced. In this context, it is of critical importance to analyze the influence of the chemical composition of perspective materials on their properties at the nanoscale. We report the fabrication of ultrathin films (thickness < 30 nm) of a family of FeII Hofmann-like coordination polymers by using an optimized liquid phase epitaxy (LPE) set-up. The series [Fe(L)2{Pt(CN)4}] (L = pyridine, pyri…
Synthesis and helical supramolecular organization of discotic liquid crystalline dibenzo[hi,st]ovalene
2019
Dibenzo[hi,st]ovalene (DBOV) has emerged as a new polycyclic aromatic hydrocarbon (PAH) with intriguing optical properties with strong red emission. Nevertheless, DBOV derivatives thus far synthesized either had mesityl groups that hinder the pi-pi stacking of the aromatic cores or showed low solubility, and the self-assembly of DBOVs has not been investigated. In this work, two 3,4,5-tris(dodecyloxy)phenyl (TDOP) groups are introduced at the meso-positions of DBOV in order to enhance its solubility without compromising the intermolecular interactions. The obtained DBOV-TDOP forms at elevated temperatures a discotic liquid crystalline phase. Due to pi-pi-stacking interactions as well as loc…
Impact of Si on the high-temperature oxidation of AlCr(Si)N coatings
2022
The resistance of wear protective coatings against oxidation is crucial for their use at high temperatures. Here, three nanocomposite AlCr(Si)N coatings with a fixed Al/Cr atomic ratio of 70/30 and a varying Si-content of 0 at.%, 2.5 at.% and 5 at.% were analyzed by differential scanning calorimetry, thermogravimetric analysis and X-ray in order to understand the oxidation behavior depending on their Si-content. Additionally, a partially oxidized AlCrSiN coating with 5 at.% Si on a sapphire substrate was studied across the coating thickness by depth-resolved cross-sectional X-ray nanodiffraction and scanning trans-mission electron microscopy to investigate the elemental composition, morphol…
Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanopart…
2022
The advancement of analytical methods for nanoparticle measurements is critical both for the growing industrial exploitation of engineered nanoparticles and for developing robust strategies to understand and control the concentration of nanomaterials in humans and the environment. For high value nanoparticles, the measurement of nanoparticle number concentration in a liquid directly impacts the ability to assess the scale and reproducibility of the production process, it allows optimisation of efficiency and supports regulatory compliance. This measurement is also useful to monitor and control the intentional or accidental release of engineered nanoparticles into the environment at the produc…
Carbon nanotubes-based nanohybrids for multifunctional nanocomposites
2017
In the present work, nano-hybrids based on carbon nanotubes (CNTs) bearing immobilized, either through covalent linkage and physical absorption, commercial anti-oxidant molecules have been formulated and used as nanofillers in Ultra High Molecular Weight Polyethylene (UHMWPE), aiming at preparing multifunctional nanocomposites. The effective immobilization of the anti-oxidant molecules has been probed by spectroscopic and thermogravimetric analyses. The study of the morphology and the rheological behaviour of the nanocomposites show that the immobilization of anti-oxidant molecules onto the CNTs surface is beneficial for the state of the polymer/nanoparticles interfacial region. Additionall…
Unveiling distribution patterns of freshwater phytoplankton by a next generation sequencing based approach.
2012
The recognition and discrimination of phytoplankton species is one of the foundations of freshwater biodiversity research and environmental monitoring. This step is frequently a bottleneck in the analytical chain from sampling to data analysis and subsequent environmental status evaluation. Here we present phytoplankton diversity data from 49 lakes including three seasonal surveys assessed by next generation sequencing (NGS) of 16S ribosomal RNA chloroplast and cyanobacterial gene amplicons and also compare part of these datasets with identification based on morphology. Direct comparison of NGS to microscopic data from three time-series showed that NGS was able to capture the seasonality in…
First Observation of Top Quark Production in the Forward Region
2015
Top quark production in the forward region in proton-proton collisions is observed for the first time. The W + b final state with W → μν is reconstructed using muons with a transverse momentum, p[subscript T], larger than 25 GeV in the pseudorapidity range 2.0 20 GeV. The results are based on data corresponding to integrated luminosities of 1.0 and 2.0 fb[superscript -1] collected at center-of-mass energies of 7 and 8 TeV by LHCb. The inclusive top quark production cross sections in the fiducial region are σ(top)[7 TeV] = 239 ± 53(stat) ± 33(syst) ± 24(theory) fb, σ(top)[8 TeV] = 289 ± 43(stat) ± 40(syst) ± 29(theory) fb.These results, along with the observed differential yields and c…
Cross-section-constrained top-quark mass measurement from dilepton events at the tevatron
2008
We report the first top quark mass measurement that uses a cross section constraint to improve the mass determination. This measurement is made with a dilepton $t\bar{t}$ event sample collected with the CDF II detector. From a data sample corresponding to an integrated luminosity of 1.2 fb$^{-1}$, we measure a top quark mass of $\rm{170.7^{+4.2}_{-3.9}(stat)\pm2.6(syst)}$ $\rm{\pm2.4(theory) GeV/{\it{c}}^{2}}$. The measurement without the cross section constraint results in a top quark mass of $\rm{169.7^{+5.2}_{-4.9}(stat)\pm3.1(syst) GeV/{\it{c}}^{2}}$.