Materials Literature
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An in-depth study has been performed of the nucleation of diamond on silicon by bias-enhanced microwave plasma chemical vapor deposition. Substrates were pretreated by negative biasing in a 2% methane-hydrogen plasma. The bias pretreatment enhanced the nucleation density on unscratched silicon wafers up to ${10}^{11}$…
Total cross sections have been measured for electron scattering on Kr, O 2 and CO in the 5-300 eV energy range utilizing a linear attenuation technique. The present results are found to be in good agreement with other experimental data for Kr and CO but deviate significantly from some of the previous measurements in t…
Protein sequences are often derived by translating genetic information, rather than by classical protein sequencing. At the DNA level cysteines and half cystines are indistinguishable. Here we show that the sequential environments of 'free' cysteine and half cystine are different. A possible origin of this difference…
We have carried out x-ray photoelectron spectroscopy on diamond thin films deposited by microwave assisted chemical vapor deposition technique using a H2-CH4 plasma. Films grown for different lengths of time, from 1 min to several hours, were analyzed for the surface composition in the C 1s and Si 2p regions. The resu…
Single‐crystal Brillouin scattering measurements of elastic moduli were performed on an eclogitic omphacite (space group C2/c) with chemical composition close to the diopside (CaMgSiO 2 O 6 , 29.9 mol %)‐jadeite (NaAlSi 2 O 6 , 57.8 mol %) join. Prom the 13 elastic moduli measured under ambient conditions we calculate…
The molecular relaxation of the liquid crystalline state of the water-cellulosic polyelectrolyte system was investigated using nuclear magnetic resonance spectroscopy (NMR) and differential scanning calorimetry (DSC). DSC and polarizing light microscopic observation showed that the system forms the liquid crystalline…
The reinforcement of polypropylene (PP) using wood cellulose has been studied. The strength and stiffness of the composites are improved by a prehydrolytic treatment of the cellulose as well as by the use of maleic anhydridemodified PP (MAPP) as a coupling agent for promoting interfacial adhesion. The embrittlement of…
Abstract A new and simplified proof of the sign of the second variation of the Oseen–Frank energy in terms of the elastic constants is given. The proof relies on the frame indifference of the energy and a new expression for the second invariant null lagrangian as a surface integral.
The antitumor activity of epirubicin (EPI) entrapped in long circulating "Stealth" liposomes containing a polyethylene glycol-derivatized phospholipid (S-EPI) was compared to epirubicin encapsulated in a conventional liposome formulation (L-EPI) and free epirubicin (F-EPI) against mouse colon 26 tumor in vivo. Pharmac…
An MSM photoconductive detector has been fabricated from porous silicon using a micromachined silicon mask instead of photolithography. This approach allows damage to porous silicon that can be caused by chemical processing to be avoided. The interdigitated pattern of the silicon mask with a finger spacing of approxim…
Abstract An attempt has been made to improve the quality of low grade wood through radiation induced wood plastic composite (WPC) formation in order to use these low grade woods as substitutes for high grade wood. Six kinds of local woods of Bangladesh (simul, korai, mango, jack fruit, teak, and garjon) were investiga…
Abstract Barbituric acid (BTA) was used as an initiator for the homopolymerization of bismaleimide (BMI). The reaction was controlled by the amount of barbituric acid and ended up with solvent‐soluble oligomers. The effects of varying the amounts of BTA, as well as the reaction time, on BMI's self‐polymerization react…
Abstract Two dilatometers are presented here that were developed for the use with, but not limited to, low‐shrink unsaturated polyester resins. One of the dilatometers, made from a glass syringe and two aluminum plates, was limited to lower pressures. The other dilatometer, similar in design to the first, was made fro…
Abstract Composites were made from polyethylene and an organic fiber (pecan shell and peanut hull flour) using a compression‐molding technique. Studies of variations in molding temperature (145–180°C), fiber concentration (0–40% by weight), and fiber mesh size (100, 200, and 325) were correlated to the mechanical prop…
We report x-ray diffraction measurements of residual stress in sapphire crystals implanted with Cr+ ions. Stress is determined by measuring both in-plane and out-of-plane lattice constants. Bragg peak positions are measured to determine average stress, while peak widths are measured to determine its variation. Using a…
The dense packing of polymeric spheres in latex films has been investigated by means of small-angle neutron scattering. The films were prepared by evaporation of the water out of a dispersion consisting of monodisperse charged particles (diameter 130 nm). Analysis of the Bragg peaks found in the scattering reveals tha…
Valence and conduction state distributions in a series of Al-Cu-Fe and Al-Cu-Fe-Cr alloys of different structural states and nominal compositions have been investigated by means of soft X-ray emission and photoabsorption spectroscopies. A complete description of the valence band is obtained. The DOS at E F is observed…
The alpha - beta , beta - gamma and gamma - delta transitions in Na 2 CO 3 are observed through frequency changes in the carbonate ion internal modes. The incommensurate phase shows particularly interesting behaviour, as the nu 4 mode splits into two components at the beta - gamma transition which represent edge singu…
The electron-energy distribution in a gold film was measured with \ensuremath{\sim}700 fs time-resolved photoemission spectroscopy following laser heating by a 400 fs visible laser pulse. The measured distribution can be fitted by the Fermi-Dirac function at an elevated temperature except within 800 fs of the heating…
The electronic structure for graphene monolayer tubules is predicted as a function of the diameter and helicity of the constituent graphene tubules. The calculated results show that approximately 1/3 of these tubules are a one-dimensional metal which is stable against a Peierls distortion, and the other 2/3 are one-di…