Materials Literature
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Abstract The 30–100 nm primary particles of mesoporous silica have been conveniently synthesized from a highly dilute aqueous solution of CnTAMX–sodium silicate.
We present the experimental and theoretical evidence that a new Sm X phase made of asymmetric bent-shaped molecules has a layered, nontilted, optically uniaxial and polarly ordered structure with random direction of the layer polarization. The randomness results from the sign degeneracy of the difference in polarizati…
Well-ordered mesostructured/mesoporous silica nanofibers have been synthesized in a quiescent dilute aqueous cationic surfactant/silica precursor reaction mixture under strong acidic conditions. These nanofibers have diameters ranging from 50 to 300 nm and lengths up to millimeters. Transmission electron microscopy (T…
A novel cross-linked siloxane-based solid polymer network has been synthesized by the hydrosilylation of polymethylhydrosiloxane (PMHS) partly substituted with oligo(ethylene glycol) methyl ether side groups and a α,ω-diallyl poly(ethylene glycol) cross-linking reagent. The ionic conductivities of the networks doped w…
Herein, we report on direct fabrication of silver circuit patterns on polyimide resin, the method of which relies on potassium hydroxide-induced chemical modification of the polyimide surface to introduce carboxylic acid groups and incorporation of silver ions through subsequent ion exchange followed by UV-irradiation…
We show that large amplitude, coherent acoustic phonon wavepackets can be generated and detected in In$_x$Ga$_{1-x}$N/GaN epilayers and heterostructures in femtosecond pump-probe differential reflectivity experiments. The amplitude of the coherent phonon increases with increasing Indium fraction $x$ and unlike other c…
The objective of this study was to develop biodegradable polypeptide-lipid conjugates for the design of polymer-coated long-circulating liposomes (LCL). Lipid conjugates of poly(hydroxyalkyl L-asparagine/L-glutamine) were synthesized and incorporated into 0.15 microm dipalmitoyl phosphatidylcholine (DPPC)-cholesterol…
Magnetism of layered cobaltites Na$_x$CoO$_2$ with $x$ = 0.6 and 0.9 has been investigated by a positive muon spin rotation and relaxation ($μ^+$SR) spectroscopy together with magnetic susceptibility and specific heat measurements, using single crystal samples in the temperature range between 250 and 1.8 K. Zero-field…
Ion conducting $(CaO)_x(SiO_2)_{1-x}$ glasses and melts show a threshold behaviour in dc conductivity near $x=x_t=0.50$, with conductivities increasing linearly at $x>x_t$. We show that the behaviour can be traced to a rigid ($x<0.50$) to floppy ($x>0.50$) elastic phase transition near $x=x_t$. In the floppy phase, co…
We demonstrate that weak external magnetic fields generate dissipationless spin currents in the ground state of systems with spiral magnetic order. Our conclusions are based on phenomenological considerations and on microscopic mean-field theory calculations for an illustrative toy model. We speculate on possible appl…
Classical molecular dynamics simulations are used to study the structure of densified germanium dioxide ($GeO_2$). It is found that the coordination number of germanium changes with increasing density (pressure) while pressure released systems do not exhibit a marked change in local structure as compared to the virgin…
Nanosized Ce 1 - x Cu x O y materials were prepared by complexation−combustion method. The structural characteristics and redox behaviors were investigated using X-ray diffraction (XRD), temperature programmed reduction (H 2 -TPR), UV−Vis, and Raman spectroscopies. In XRD patterns, no evidence of CuO diffraction peaks…
Polyimide-tethered polyhedral oligomeric silsesquioxane, (R 7 R‘Si 8 O 12 ) (POSS), nanocomposites with well-defined architectures are prepared by the copolymerization reaction of a new type of diamine monomer: POSS-diamine, 4,4‘-oxydianiline (ODA), and pyromellitic dianhydride (PMDA). This type of polyimide-side-chai…
<div class="htmlview paragraph">Reducing the emissions and fuel consumption are no longer future goals; instead they are the demands of the day. People are concerned about rising fuel costs and effects of emissions on the environment. Diesel engines are the major contributors to the increased levels of pollutant…
Abstract Chitosan has been increasingly studied as an adsorbent for removing heavy metal ions and organic compounds from aqueous solutions. Most of the studies used chitosan in the form of flakes, powder, or hydrogel beads. This research investigates the immobilization of chitosan on other granular materials to overco…
<div class="htmlview paragraph">The unsteady flow effects in two different close coupled catalytic converters were investigated in order to achieve a better understanding of the steady state experimental tests which are usually performed to evaluate a flow distribution.</div> <div class="htmlview paragr…
Abstract ABTSRACT: Biodegradable plastics based on soy dreg (SD) were prepared with glycerol as a plasticizer via compression molding at 110–160°C. The effects of the glycerol content and molding temperature on the processability and mechanical properties were investigated. For enhanced water resistivity of the SD pla…
Abstract A new series of discrete [(hfac)3Ln(μ-bpypz)Cr(acac)2] dinuclear complexes has demonstrated the novel LnIII ion size depedent structural transformation around LnIII as well as diastereospecifically assembled chiral configuration along with the unusual bending of the acetylacetonate chelate ring in CrIII.
Abstract This article examines the anionic polymerization of lauryl lactam into polyamide 12 and the copolymerization of lauryl lactam with a diisocyanate‐end‐capped polycaprolactone used to produce a poly(ester amide) block copolymer. The molecular weights of the polyester polyols used in the preparation of the diiso…
The polymerization of propylene oxide (PO) catalysed by maghnite-H+ (mag-H+) in the presence of ethylene glycol was investigated. Mag-H+ is a montmorillonite silicate sheet clay was prepared through a straight forward proton exchange process. It was found that the cationic polymerization of PO was initiated by mag-H+…