Materials Literature
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Auger-like exciton-exciton annihilation in isolated single-walled carbon nanotubes (SWNTs) has been studied by femtosecond transient absorption spectroscopy. We observe a quantization of the Auger recombination process and extract dynamics for 2 and 3 electron-hole pair excited states. We further demonstrate that Auge…
The self-assembly of the dendritic dipeptides (4-3,4-3,5)nG2-CH2-Boc-L-Tyr-L-Ala-OMe and their achiral dendritic alcohol (4-3,4-3,5)nG2-CH2OH precursors, both with n = 1-16, where n represents the number of methylenic units in the alkyl groups of the dendron, are reported. All chiral dendritic dipeptides and achiral d…
Abstract meso ‐Aryl‐substituted expanded porphyrins are structural analogues of meso ‐aryl‐substituted porphyrins. They exhibit rich and novel coordination behaviors, including multi‐metal chelation due to the large cavities, spin–spin interaction arising from the proximity of metal centers, and large changes in their…
Using AFM (atomic force microscopy) to probe protein conformation and arrangement, and TIRF (total internal reflectance fluorescence) to monitor kinetics, fibrinogen adsorption on three different silica-based surfaces was studied: the native oxide on silicon, acid-etched microscope slides, and acid-etched polished gla…
This paper describes the use of galvanic cell reaction as a facile method to chemically deposit Ag nanostructures on the p -silicon wafer on a large scale. When the Ag covered silicon wafer is further modified with a self-assembled monolayer of n -dodecanethiol, a superhydrophobic surface can be obtained with a contac…
We report on infrared (IR) spectro-microscopy of the electronic excitations in nanometer-thick accumulation layers in FET devices based on poly(3-hexylthiophene). IR data allows us to explore the charge injection landscape and uncovers the critical role of the gate insulator in defining relevant length scales. This wo…
We grew SrTiO3 on SrTiO3(001) by pulsed laser deposition, using x-ray scattering to monitor the growth in real time. The time-resolved small-angle scattering exhibits a well-defined length scale associated with the spacing between unit-cell high surface features. This length scale imposes a discrete spectrum of Fourie…
We report on the synthesis and self-assembly of a new series of discotic molecules containing triphenylbenzene as the core and alkoxy side chain with varying length. It was found that compounds 3 a-c, 4 b and 5 b could form stable gels in several apolar solvents. Transmission electron microscopy (TEM) images revealed…
We report the measurements of the temperature dependence of the resistivity, ρ(T), magnetic penetration depth,λ(T) the lower, Hc1(T), and upper, Hc2(T), critical magnetic fields, for single crystals of dodecaboride ZrB12, diboride ZrB2 and thin films of diboride MgB2. We observe a number of deviations from conventiona…
Photoswitching of the dielectric constant has been observed for the first time in the spin-crossover complex [Fe(L)(CN)2]⋅H2O (L=2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene, see picture). The electrical detection of a photoinduced change in spin state could allow the use of…
Results from experiments performed on the motion of drops of tetraethylene glycol in a wettability gradient present on a silicon surface are reported and compared with predictions from a recently developed theoretical model. The gradient in wettability was formed by exposing strips cut from a silicon wafer to dodecylt…
Thermoelectric properties of a nanocontact made of two capped single wall carbon nanotubes (SWCNT) are calculated within the tight-binding approximation and by using Green's function method. It is found that doped semiconducting nanotubes can have high Seebeck coefficients. This in turn leads to very high figures of m…
We analyze a new family of carbon nanotube-based molecular wires, formed by encapsulating metallocene molecules inside the nanotubes. Our simulations, that are based on a combination of non-equilibrium Green function techniques and density functional theory, indicate that these wires can be engineered to exhibit desir…
0.5 to 5.0 wt.% Dy2O3 was in-situ reacted with Mg + B to form pinned MgB2. While Tc remained largely unchanged, Jc was strongly enhanced. The best sample (only 0.5 wt.% Dy2O3) had a Jc of 6.5 x 10^5 A/cm^2 at 6K, 1T and 3.5 x 10^5 A/cm^2 at 20K, 1T, around a factor of 4 higher compared to the pure sample, and equivale…
Materials characterized by spatially homogeneous elastic moduli undergo affine distortions when subjected to external stress at their boundaries, i.e., their displacements $\uv (\xv)$ from a uniform reference state grow linearly with position $\xv$, and their strains are spatially constant. Many materials, including a…
Abstract In the present study two series of isotactic polypropylene (iPP)/SiO 2 nanocomposites containing 1, 2.5, 5, 7.5, and 10 wt % SiO 2 nanoparticles were prepared by melt‐mixing on a twin‐screw corotating extruder. In the first series untreated fumed silica nanoparticles were used, whereas in the second nanoparti…
Marine mussels anchor to a variety of surfaces in turbulent intertidal zones through the use of adhesive plaques formed from hardened mussel adhesive proteins (MAPs). It is believed that 3,4-dihydroxyphenylalanine (DOPA) imparts both water-resistant adhesive characteristics and rapid curing ability to MAPs. In this pa…
Neutron diffraction measurements under high magnetic fields have been performed for the multiferroic compound HoMn$_{2}$O$_{5}$. At zero field, high-temperature incommensurate magnetic (HT-ICM) -- commensurate magnetic (CM) -- low-temperature incommensurate magnetic (LT-ICM) orders occur with decreasing temperature, w…
The dynamics of a rotating elastic filament is investigated using Stokesian simulations. The filament, straight and tilted with respect to its rotation axis for small driving torques, undergoes at a critical torque a strongly discontinuous shape bifurcation to a helical state. It induces a substantial forward propulsi…
We independently determine the subpicosecond cooling rates for holes and electrons in CdSe quantum dots. Time-resolved luminescence and terahertz spectroscopy reveal that the rate of hole cooling, following photoexcitation of the quantum dots, depends critically on the electron excess energy. This constitutes the firs…