Vector Aberration Theory And The Design Of Off-Axis Systems
A simple aberration theory is described for systems containing tilted and decentered surfaces. Design principles are developed and applied to two and three mirror systems.
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Metal-TiO2 Catalysts
The electronic behaviour of Pt, Rh and Ni/TiO 2 catalysts was followed by measuring in situ the conductivity σ of the support. From σ variations at room T, it is deduced that the metal is always enriched in free electrons from the support and that H 2 chemisorption is followed by H spill over on the oxide. On Pt/TiO 2…
Surface-limited release of deuterium from iron and the effect of surface oxygen
The surface-limited release of deuterium from solution in polycrystalline iron was measured in ultrahigh vacuum using nuclear reaction analysis and ion implantation with surface characterization by Auger electron spectroscopy. For a bare iron surface the magnitude and temperature dependence of the release rate are qua…
Molecular imaging of tobacco mosaic virus lyotropic nematic phases
Aqueous solutions of tobacco mosaic virus are ideal systems for visualizing ``molecular'' distributions in the nematic phase by freeze-fracture electron microscopy. The order parameter in well aligned regions is measured to be greater than 0.9. Twist deformations appear to be most common, confirming that the twist ela…
NMR study of the structure and motion of charge density waves inNbSe3
The authors report NMR measurements of the $^{93}\mathrm{Nb}$ resonance in the charge-density-wave (CDW) conductor ${\mathrm{NbSe}}_{3}$ on aligned, multicrystalline samples. They have observed the resonance with and without current flow in the sample at temperatures above 59 K, where a single incommensurate CDW is pr…
Hydrogen absorption and desorption in Nd2Fe14B
Absorption and desorption of hydrogen by the permanent magnet material Nd2Fe14B have been studied using a microcomputer-controlled, thermomanometric analyzer with an initial hydrogen pressure of approximately 1 bar. Primary absorption occurs in the range 200–300 °C and results in the formation of a stable hydride with…
Photogeneration of confined soliton pairs (bipolarons) in polythiophene
From photoinduced absorption and light-induced electron-spin resonance, we demonstrate that the dominant photocarriers generated in polythiophene with excitation above the energy gap (${E}_{g}$) are charged bipolarons (spin 0). The observation of bipolarons (${B}^{2\ifmmode\pm\else\textpm\fi{}}$) rather than polarons…
Electron paramagnetic resonance of Tm3+ ions in lanthanide nicotinate dihydrates
Abstract E. p. r. at microwave frequencies in single crystals of lanthanum nicotinate dihydrate (LaND) doped with ca. 0.01 mole fraction of thulium shows no spectrum of isolated Tm3+ ions, but does exhibit spectra from coupled pairs of nearest-neighbour Tm3+ ions. The spin hamilton parameters are approximately the sam…
Flame‐retardant viscose–polyester fabrics
Abstract For many purposes the natural‐synthetic fiber‐blend fabrics are more suitable than pure natural or synthetic products. It is often possible to obtain a maximum in clothing and textile technical properties by compensating the defects of one fiber by using an other totally different fiber. Many problems, howeve…
Postirradiation polymerization of vinyl monomers on poly(ethylene terephthalate)
Abstract A postirradiation process was evaluated in polymerizing vinyl monomers on poly(ethylene terephthalate) (PET) film, fiber, and fabric. The use of DMF, pyridine, and DMSO as swelling agents to facilitate monomer incorporation and effective polymerization were also investigated. The solvents were effective in pr…
Studies on thermal degradation of cellulose and cellulose phosphoramides
Abstract Reaction of cellulose with hexamethylphosphoric acid triamide has been investigated under various physical conditions. Dimethylamine hydrochloride was found to be an efficient catalyst for the system. The thermal degradation of cellulose and its phosphoramide products in air was studied by DTA, TG, and DTG te…
Preparation of Tri‐O‐alkylcellulose by the use of a nonaqueous cellulose solvent and their physical characteristics
Abstract Tri‐ O ‐methyl‐, ‐ethyl‐, ‐ n ‐propyl‐, ‐ n ‐butyl‐, ‐ n ‐pentyl‐, ‐iso‐amyl‐, ‐ n ‐hexyl‐, ‐ n ‐heptyl‐, ‐ n ‐octyl‐, ‐ n ‐decyl‐, and ‐3‐phenoxypropyl‐celluloses have been prepared with powdered sodium hydroxide and the corresponding alkyl iodides or bromides in one of nonaqueous cellulose solvents, SO 2 ‐d…
Swelling properties of copolymeric hydrogels prepared by gamma irradiation
Abstract Crosslinked xerogels in the form of rods have been prepared to > 99.9% conversion by the γ‐ray initiated copolymerization in vacuo ob n ‐butyl acrylate (BA) with N ‐vinyl‐2‐pyrrolidone (VP) in the presence and absence of a crosslinking agent. Thin (about 0.5 mm) disks were swollen in water at 21°C, the fin…
An ESR Study of the Radical Cations of Tetrathiafulvalene (TTF) and Electron Donors Containing the TTF Moiety
Abstract Hyperfine data and g factors are reported for the radical cations of tetrathiafulvalene (TTF; 1 ) and of its derivatives 2–13 . From the intense satellite spectra of 1 + – 13 + not only the coupling constants of the 33 S isotopes in the TTF moiety could be determined, but also, in favourable cases, those of t…
Dynamic mechanical and impact properties of PP/SEBS blend
Abstract Studies on impact behaviour of the blend of isotactic polypropylene (PP) with styrene‐ b ‐ethylene‐co‐butylene– b ‐styrene triblock copolymer (SEBS) in the composition range 0–25 wt % SEBS at three temperatures, viz., ambient, −30°C, and −190°C, are presented. Dynamic mechanical properties on a torsion pendul…
Chiral metals? A chiral substrate for organic conductors and superconductors
Abstract Chiral metals are so far practically unknown. The synthesis of a chiral substrate for possible organic conductors and superconductors is described.
Spin-dependent photoemission intensities from solids
We observed that the photoemission intensity from solids may depend explicitly on the spin state of the photoexcited electrons. This new phenomenon is explained by spin-dependent transmission through the surface of solids with nonvanishing spin-orbit coupling. It is demonstrated for photoemission from Pt(111) with ell…
X-ray study of high-density amorphous water
X-ray diffraction measurements were performed at atmospheric pressure on a high-density form of amorphous ice obtained by pressurizing crystalline ice Ih at 77 K, up to 2 GPa. The low--momentum-transfer region of the determined structure factor is quite different from that corresponding to the low-density form of amor…
Surface-energy-driven secondary grain growth in thin Au films
Secondary grain growth in thin Au films on SiO2 substrates is reported. Secondary grains have {111} texture which minimizes the surface energy. This indicates that surface energy anisotropy provides selectivity in the driving force for growth of secondary grains. In thin Au films on SiO2, surface-energy-driven seconda…
Polarization and tilt-angle measurements near the smectic-A–chiral–smectic-Ctransition ofp-(n-decyloxybenzylidene)-p-amino-(2-methyl-butyl)cinnamate (DOBAMBC)
For a given temperature below the smectic-A (SmA)--chiral--smectic-C (${\mathrm{SmC}}^{\mathrm{*}}$) transition of DOBAMBC, polarization (P) and tilt-angle (theta) have been measured almost simultaneously with high resolution. The ratio P/theta stays fairly constant for ${\mathrm{T}}_{\mathrm{c}}$-T>2 K and shows a…