Materials Literature
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An immersion grating with a high refractive index, n, increases the spectral resolution by a factor n over that of a reflective surface grating of equal length. A silicon immersion grating has been developed and tested; initial results are reported here.
Abstract Blends of Thermoplastic polyurethane (TPU) and poly(styrene‐co‐acrylonitrile) (SAN) (34% acrylonitrile and 24% acrylonitrile) and polyurethane ionomer (PUI) with SAN (34% acrylonitrile) were prepared in the melt. The structural properties and morphology of the blends were investigated. TPU and SAN blends were…
Abstract This article includes the doping and dedoping behaviors, the electrical conductivity, and the spectral properties of poly(2‐ethynylpyridine) and iodine‐doped poly(2‐ethynylpyri‐dine). The doping ability of poly(2‐ethynylpyridine) having a pyridine substituent was greater than that of polyphenylacetylene havin…
Abstract Cellulose fibers were grafted with compatibilizing agents, such as maleated polypropylenes of different molecular weights. Steric effects and surface free‐energy effects were found to stimulate the stretching of grafted chains away from the cellulose fiber surface, giving rise to a brushlike configuration in…
Abstract Preliminary investigations have been conducted on the graft copolymerization of meth‐ylmethacrylate onto Caesarweed fiber, initiated by potassium permanganate and the toluene redox system. The percentage graft yield increased with permanganate up to 132% in the concentration range, 1.0×10 −2 to 5.0×10 −2 M at…
A particularly popular and powerful use of fluorescent indicators is nondestructive monitoring of the activity or free concentration of important ions or messengers such as Ca 2+, H +, Na +, Mg 2+, Cl -, or cyclic adenosine 3′,5′-monophosphate (cAMP) inside living cells and tissues. Successful indicators and chelators…
Light scattering and absorption by spherical particles is extended to aggregates of spheres with arbitrary shape and size. We applied the theory of G6rardy and Ausloos [Phys. Rev. B 25, 4204-4229 (1082)] to compute the total extinction loss spectra of several aggregates of nanometer-sized silver spheres from the near…
Electric field-induced changes in the extraordinary and ordinary refractive indices of a Pb(Zr0.53Ti0.47)O3 thin film were independently determined using waveguide refractometry. Under an electric field, applied normal to the film plane and corresponding to saturation of the electric polarization, the ratio of the ext…
A novel hard magnetic compound series with composition Sm2Fe14Ga3Cx (x=0, 0.5, 1.0, 1.5, 2.0, and 2.5) was prepared by arc melting. The carbides crystallize in the rhombohedral Th2Zn17-type structure and are single phase except for Sm2Fe14Ga3 and Sm2Fe14Ga3C0.5 which contain some amounts of α-Fe. The substitution of G…
Free-standing chemically vapor deposited (CVD) single-crystalline diamond films have been fabricated by a sequence of processes including high energy ion implantation, microwave plasma enhanced chemical vapor deposition, and the final separation of the diamond epilayer from the substrate by heating in oxygen. The homo…
The dynamics of a very fragile glass-forming polymer is studied by time of flight neutron scattering in a time scale from ${10}^{\mathrm{\ensuremath{-}}13}$ to ${10}^{\mathrm{\ensuremath{-}}11}$ s. We observe a crossover from a Debye-like to a non-Debye behavior at a characteristic time which is effectively independen…
The diffusion (${\mathit{D}}_{\mathit{s}}$) of entangled and unentangled symmetric block copolymers is compared, above and below the ordering transition. The lamellar samples were not macroscopically oriented, and thus ${\mathit{D}}_{\mathit{s}}$ reflects a combination of mobilities parallel and perpendicular to the l…
The process of wetting of a monodisperse foam by the continuous addition of liquid from the top has been investigated for a cylindrical column. The velocity of the interface between dry and wet foam was found to vary as the square root of the rate of addition of liquid. Evidence of a structural transformation was foun…
Magnetic resonance and calorimetric studies of 4'-n-pentyl-4-cyanobiphenyl confined to Vycor glass, a random network of pores with average diameter \ensuremath{\sim}70 \AA{}, are reported. Under such severely constrained ocnditions, the nematic-to-isotropic transition is replaced by a continuous evolution of orientati…
The dark current in commercial polypropylene (PP) is measured at temperatures ranging from 333 to 413 K and fields ranging from 70 to 125 kV/cm. The specimens are metallized on both sides by evaporated layers of silver and aluminium. An attempt is made to identify the nature of the current by comparing its observed de…
Electrochromic MnOx thin films are prepared by using an electron beam technique followed by annealing post-treatment. Electrochromic properties of the films are studied in three different solutions: 1M LiClO4 in propylene carbonate, KOH (pH = 10.5), and natrium borate (pH = 9.2). The transmittance spectra of the colou…
During the four decades from 1930 to 1970, seven photocathodes having useful sensitivity to visible light were developed. The first six have two features in common: First, they were all based on lucky observations, rather than on scientific principles. Second, despite a great deal of systematic research it is still no…
The copper and nickel complexes of 2,3,7,8,12,13,17, 18-octabromo-5,10,15,20-tetrakis(pentaftuorophenyl) \nporphyrin ({4,5,9,10,14,15,19,20-octabromo-2,7,12,17-tetrakis(pentaftuorophenyl)-21,22,23,24-tetraazapentacyclo[l6.2.1.1^(3,6).l^(8,11).l^(13,16)]tetracosa-l,3-(22),4,6,8(23),9,11,13(24),14,16,18(21),19-dodec…
A study was made of the structure and magnetic properties of Fe-Co alloy films produced by dc magnetron sputtering at an oblique angle of incidence. The films obtained in this manner showed uniaxial magnetic anisotropy in the film plane, with an easy axis of magnetization perpendicular to the incident direction of the…
CdS microcrystals under weak confinement conditions embedded in a polyvinyl alcohol polymer film have been optically characterized by linear absorption and time-resolved luminescence spectroscopy. They are studied in the presence of an external electrical field at low and room temperature and different densities of ph…