Materials Literature
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A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- dia…
We use the Leslie–Ericksen theory to simulate the shear flow of tumbling nematic polymers. The objectives are to explore the onset and evolution of the roll-cell instability and to uncover the flow scenario leading to the nucleation of disclinations. With increasing shear rate, four flow regimes are observed: stable s…
Abstract Previously, isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMAs) (designated as iPMMA, aPMMA, and sPMMA) were mixed with poly(vinyl phenol) (PVPh) separately in tetrahydrofuran (THF) to make three polymer blend systems. According to calorimetry data, iPMMA was found to be miscible with PVPh…
ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under ZV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after ~ 40 hrs. The fi…
Abstract Mn(II) ion binds to human serum albumin (HSA) through one strong binding site ( K A = 7.9 × 10 3 M −1 ) and several weaker binding sites. Through competition assays it has been shown that the strong binding site lies in a region which has been previously identified as the Cd(II) Zn(II) site. The binding of M…
Abstract Hard segment hydrogen bonding interactions in a particular polyurethane segmented copolymer have been analysed through a viscometric approach to determine the behaviour of polyurethane solutions with different solvent compositions. Analysis of log η sp versus log c [ η ] master curves (solely comprising dilut…
The in situ measurement capabilities and advantages of recently developed spectroscopic ellipsometry (SE) instrumentation, which covers wide spectral ranges (190-1700 nm, or 0.73-6.5 eV) and is based on rotating-compensator technology, are described. A technique which can quantitatively correct for window birefringenc…
Chemical ordering of the B-site cations in undoped, 5, 10, 20, and 30 mol % La3+-doped Pb(Mg1/3Nb2/3)O3 (PMN) ceramics with perovskite structure, has been examined by Raman scattering. Two B-site chemical ordering models, the space-charge model, and the random layer model assume a space group of Fm3̄m for the ordered…
CdSe, InP, and ZnO colloidal quantum dots of 1.5--2.5 nm radius show 3 meV homogeneous width at 10 K for the midinfrared ${1S}_{e}{\ensuremath{-}1P}_{e}$ intraband transition around 300 meV. A weak temperature dependence leads to a homogeneous width of less than 10 meV at 200 K for 2.3 nm radius CdSe. The strength of…
The coupling of a semimetallic carbon nanotube to a surface acoustic wave (SAW) is proposed as a vehicle to realize quantized adiabatic charge transport. We demonstrate that electron backscattering from a periodic SAW potential can be used to induce a miniband spectrum at energies near the Fermi level. Within the fram…
Abstract Star‐shaped low molecular weight poly(ε‐caprolactone)s (PCLs) were synthesized and functionalized with crosslinkable terminal groups for subsequent crosslinking. The ε‐caprolactone (CL) prepolymers were polymerized by ring‐opening in the presence of polyglycerine (PGL) as an initiator (1, 3 and 5 mol%) and Sn…
Abstract Two different biodegradable polyesters [polycaprolactone (PCL) and poly(3‐hydroxybutyrate ‐co‐ valerate) (PHBV)] were blended with a maize starch that had high amylose content through the use different reactive approaches. The compatibilization of both systems was obtained. PCL/starch composites were obtained…
Silicon nanocrystals were prepared by laser pyrolysis of silane in a gas flow reactor and deposited on substrates by cluster beam deposition. The evolution of the photoluminescence was measured as a function of the time the samples were exposed to air. With gradual air exposure and oxidation, the photoluminescence inc…
Li-doped films with controlled stoichiometries were prepared by performing redox reactions between single-wall carbon nanotubes thin films and solutions of organic radical anions. A monotonic upshift of the tangential modes is evidenced for ${\mathrm{Li}}_{x}\mathrm{C}$ compounds $(0<~x<~0.17).$ A similar doping…
Abstract Liquefaction of waste paper (WP) was conducted in the presence of polyhydric alcohols to prepare biodegradable polyurethane foam. The liquefied‐WP‐based polyol had suitable characteristics such as apparent molecular weight, hydroxyl value, and viscosity for the preparation of rigid polyurethane foam and was s…
This review describes work on the conformational stability of the collagen triple helix. In 1994, the structure of collagen was determined at high resolution. Since then, much work has been done on synthetic mimics of collagen that contain host-guest peptides, tethers, peptoid residues, or analogs of the prevalent 4(R…
We present a coupled atomistic-continuum method for the modeling of defects and interface dynamics of crystalline materials. The method uses atomistic models such as molecular dynamics near defects and interfaces, and continuum models away from defects and interfaces. We propose a new class of matching conditions betw…
A ${\mathrm{TiS}}_{2}$ crystal with a layered structure was found to have a large thermoelectric power factor. The in-plane power factor ${S}^{2}/\ensuremath{\rho}$ at 300 K is $37.1\ensuremath{\mu}{\mathrm{W}/\mathrm{K}}^{2}\mathrm{cm}$ with resistivity (\ensuremath{\rho}) of 1.7 m\ensuremath{\Omega} cm and thermopow…
Even though our theoretical understanding of dendritic solidification is relatively well developed, our current ability to model this process quantitatively remains extremely limited. This is due to the fact that the morphological development of dendrites depends sensitively on the degree of anisotropy of capillary an…
We show that the choice of the sign of the hopping matrix in our impurity band model for disordered III-V diluted magnetic semiconductors [PRL 87, 107293 (2000); cond-mat/0111045] is justified: with this choice, the impurity band is placed inside the gap and it has a mobility edge, as expected for a disordered system.…