Materials Literature
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Abstract This paper reviews new approaches to size‐controlled silicon‐nanocrystal synthesis. These approaches allow narrowing of the size distribution of the nanocrystals compared with those obtained by conventional synthesis processes such as ion implantation into SiO 2 or phase separation of sub‐stoichiometric SiO x…
We describe a simple and versatile technique to produce magnetic tubes by filling carbon nanotubes (CNTs) with paramagnetic iron oxide particles ( approximately 10 nm diameter). Commercial ferrofluids were used to fill CNTs with an average outer diameter of 300 nm made via chemical vapor deposition into alumina membra…
Many microscopy studies require reconstruction from serial sections, a method of analysis that is sometimes difficult and time-consuming. When each section is cut, mounted and imaged separately, section images must be montaged and realigned to accurately analyse and visualize the three-dimensional (3D) structure. Reco…
Fourier transform (FT) is a fundamental step for the data reduction and interpretation of extended x-ray absorption fine structure (EXAFS) spectra. The FT separates backscattering atoms by their radial distance from the absorbing atom (so-called shells). We suggest to routinely complement the FT by a wavelet transform…
We report ultra-efficient multiple exciton generation (MEG) for single photon absorption in colloidal PbSe and PbS quantum dots (QDs). We employ transient absorption spectroscopy and present measurement data acquired for both intraband as well as interband probe energies. Quantum yields of 300% indicate the creation,…
Particularly uniform: Monodisperse ferrite microspheres can be synthesized to have diameters of about 200–800 nm (TEM image, left). High-resolution TEM analysis (image, right and inset) shows that each microsphere is a single crystal. Their hydrophilic and magnetic properties impart to the microparticles many potentia…
The electronic and atomic structures of quasi-one-dimensional blue bronze K0.3MoO3 were investigated by polarization-dependent O K-edge x-ray absorption near-edge structure (XANES) and Mo K-edge extended x-ray absorption fine structure (EXAFS) measurements at various temperature and applied voltages. The O K-edge XANE…
The effects of changing the host-lattice isotopes from natural silicon (approximately $^{28}\mathrm{Si}$) to $^{30}\mathrm{Si}$ are reported for some of the important local vibrational modes (LVMs) observed in as-grown and electron-irradiated Czochralski silicon. We show that the quanta of the LVMs shift to lower ener…
Recently, a hyperelastic-viscoplastic constitutive model was developed for PET and the noncrystallizing copolymer PETG (R. B. Dupaix, Ph.D. thesis, MIT, 2003). The materials were found to behave very similarly under monotonic loading conditions and the single constitutive model was able to capture both materials’ beha…
The sol–gel technique has been used to produce Ag–SiO2 nanocomposite thin films consisting of silver nanoparticles embedded in a SiO2 matrix. The size of the silver nanoparticles is of about (4±0.2)nm when the firing temperature is in the (500–700°C) range, as determined from ultraviolet-visible spectroscopy analysis.…
Abstract Isothermal and non‐isothermal crystallization kinetics of microbial poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyhexanoate) [P(3HB‐3HHx)] was investigated by differential scanning calorimetry (DSC) and 13 C solid‐state nuclear magnetic resonance (NMR). Avrami analysis was performed to obtain the kinetic parameters of…
We report a technique for the alignment of self-assembled protein systems, such as F-actin bundles and microtubules, in a surface-modified titanium or silicon microfluidic device. Assembling filamentous protein systems in a confined geometry produces highly aligned samples for structural and mechanical studies. Biomol…
The impact of C atoms and ${\mathrm{C}}_{60}$ molecules with ideal diamond and silicon (100) substrates and the subsequent growth of carbon films have been investigated by molecular dynamics simulations. The interatomic many-body potential proposed by Tersoff has been used. The structural and vibrational properties of…
3-phosphoglycerate kinase (PGK) is a typical two-domain hinge-bending enzyme with a well-structured interdomain region. The mechanism of domain-domain interaction and its regulation by substrate binding is not yet fully understood. Here the existence of strong cooperativity between the two domains was demonstrated by…
Sol−gel boria−alumina mixed oxides with a wide range of B/Al atomic compositions have been characterized as dried xerogels in the preceding paper in which a structural model with four domains of composition was proposed. The present paper presents the results obtained on the same series of solids after calcination at…
Epitaxial behavior of (Pb,Sr)TiO3 thin films on (110) NdGaO3 substrates fabricated in different conditions have been investigated using high resolution x-ray diffraction and characterized with interdigital dielectric measurement. A slow cooling results in films with a-axis normal to the surface (a-axis growth), wherea…
We report an experimental study by electron paramagnetic resonance (EPR) of ${E}_{\ensuremath{\delta}}^{\ensuremath{'}}$ point defect induced by $\ensuremath{\gamma}$-ray irradiation in amorphous $\mathrm{Si}{\mathrm{O}}_{2}$. We obtained an estimation of the intensity of the 10 mT doublet characterizing the EPR spect…
The structures of polydisulfide-based biodegradable macromolecular Gd(III) complexes were modified to improve their in vivo retention time and MRI contrast enhancement. Steric hindrance was introduced around the disulfide bonds to control their access to free thiols in order to alter the degradation rate of the copoly…
The phenomenon of on-off luminescence intermittency---blinking---in silicon nanocrystals was studied using a single-dot microphotoluminescence technique. From recordings of the luminescence intensity trace, on- and off-time distributions were extracted revealing exponential behavior, as expected for systems with blink…
The inclusion of Tb3+ ions doped into the storage phosphor BaFBr:Eu2+ results in increased purity of the host material as well as an improvement in the linearity of the photostimulated luminescence (PSL) intensity versus the x-ray irradiation dose. Films produced by pulsed laser deposition (PLD) also show similar resu…