Materials Literature
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We have operated a supertip-type field emitter to provide electron beams of low angular divergence and high intensity. The beams obtained from a supertip on a W tip are characterized by narrow emission angles of , effective emission areas of and energy spreads of eV (FWHM) at stable total emission currents of nA. The…
Poly(dimethylsiloxane) (PDMS) and aromatic polyamide (aramid) multiblock copolymers (PASs) ranging from 26 wt % to 75 wt% in PDMS content were prepared and cast into transparent, ductile, and elastomeric films from N,N′-dimethylacetamide solutions. The gas permeation properties and dynamic thermomechanical properties…
Disiloxane–aromatic polyamide(aramid) multiblock copolymers(2SiPASs) were synthesized using 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane(BATS) as an analog of aramidsilicone resin consisting of aromatic polyamide and poly(dimethylsiloxane) (PDMS). 2SiPASs afford a transparent and toughened plastic film. The su…
Real ferroelectric capacitors are usually asymmetric. In this paper, the current - voltage characteristic of asymmetric Pt/Pb(Zr,Ti) /Pt (Pt/PZT/Pt) thin film capacitors is studied quantitatively by using an asymmetric totally depleted back-to-back Schottky model as well as by experiment. The model successfully descri…
Surface morphology of asymmetric and homogeneous membranes prepared from poly(phenylene oxide) (PPO) was studied by tapping mode atomic force microscopy (TMAFM). As expected, a significant difference in the morphology between the top and the bottom surfaces of the asymmetric membrane was observed. The images of the to…
Reflection high energy electron diffraction (RHEED) intensity measurements reveal that the strain in a Si1-xGex layer on a vicinal Si(001) surface converts a (1 X 2) domain dominated step configuration to a (2X1) domain dominated one. The dependence of the effect on the Ge content is similar to the dependence of the c…
Abstract Over the past three years, the Oilfield Scale Research Group at Heriot-Watt has conducted a number field studies to evaluated scale inhibitors for both downhole squeeze application and topside continuous injection for a number of North Sea operating companies. This paper presents an approach for screening com…
Blends of poly(styrene)-block-poly(ethene-co-but-1-ene)-block-poly(styrene) (SEBS) with isotactic polypropylene (PP) and syndiotactic PP, respectively, were investigated. The morphology was observed by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The cryofracture surfaces stu…
We present simulations of flux-gradient-driven superconducting vortices interacting with strong columnar pinning defects as an external field $H(t)$ is quasi-statically swept from zero through a matching field $B_ϕ$. We analyze several measurable quantities, including the local flux density $ B(x,y,H(t))$, magnetizati…
In the theory of electric strength, usually referred to as free-volume theory, breakdown is initiated by free electrons accelerated by electric field in the largest of the holes present in the amorphous phase of all polymers. In contrast to previous publications, the breakdown is treated as the final stage of the disp…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Radially and azimuthally oriented liquid crystal (LC) alignment patterns, which are hard to achieve by conventional LC alignment techniques, have been realized by exposure of polyimide surfaces to linearly polarized ultraviolet radiation. These surfaces can be used to realize some special LC configurations which are u…
Copper deposition based on a newly synthesized metalorganic compound shows promise for reproducible deposition which has been a major problem. The deposition can be carried out without adverse effect on the film qualities at the bubbler temperature of 65 °C. Preliminary deposition results reveal that the resistivity i…
Temperature and compositional dependences of electrical conductivity in lead - iron glasses are reported. The experimental results are analysed in the light of existing theories. It has been observed that the electrical conduction in these glass compositions at high temperatures is best described by Mott's phonon-assi…
Mesoscopic ordering processes have been found in binary polymer mixtures where only one polymer component was selectively cross-linked by irradiation with ultraviolet light. Depending upon the competitions between the reaction and the phase separation, the mixture can be destabilized and exhibits a wide range of mesos…
The amplitude $\ensuremath{\Delta}\ensuremath{\rho}(T,H)/\ensuremath{\rho}$ and temperature ${T}_{M}$, where the colossal magnetoresistance (CMR) response of ${L}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ manganites are maximum, are found to be controlled by the radius of the lanthanide $({L}^{3+})$ which…
An extension to chiral phases of a model derived previously to interpret orientational properties in liquid crystal solvents of molecules with arbitrary shape leads, quite naturally, to the definition of a traceless chirality tensor, useful for predicting the structures of twisted nematics induced by chiral solutes. T…
New biocomposites with dynamically active properties were synthesized containing the conducting electroactive polymer, polypyrrole, dextran sulphate and a range of proteins. These composites have a hydrophilic matrix with a high water content and confer on the conducting polymer several properties useful in the design…
The thermomechanical properties of a thin film of shape memory polymer of polyurethane series were investigated experimentally. The results were summarized as follows: (1) Modulus of elasticity and yield stress are high below glass transition temperature T<SUB>g</SUB> and low above T<SUB>g</SUB>. The value of loss tan…
One-photon laser excitation of Xe(6s[3/2]2) and Kr(5s[3/2]2) atoms that were generated in a discharge-flow reactor was used to study the collisional relaxation of the Kr(5p′[3/2]1, [3/2]2, and [1/2]1), the Xe(7p[3/2]2, [3/2]1, [5/2]2, and [5/2]3), and the Xe(6p′[3/2]1, [3/2]2, and [1/2]1) states in He and Ar. Both cw…