Materials Literature
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New ENDOR measurements on the single substitutional nitrogen centre in diamond are reported. The CW-ENDOR mechanism utilizes cross relaxation, and measurements have been made on both 14 N and 15 N, as well as the first detailed 13 C ENDOR study on the isotope at the natural abundance of 1.1%. The change in EPR intensi…
Abstract Cellulose fibers have been surface‐modified by selected cold, microwave plasma treatments. Inverse gas chromatographic (IGC), XPS, and SEM analyses showed surface treatment to be incomplete, but, nevertheless, effective in controllably altering the acid/base interaction balance of fiber surfaces. Surface‐modi…
The visible luminescence of porous Si is known to contain at least two spectrally distinct emission bands with widely different response times. The orange-red luminescence component (1.5–1.9 eV) decays in times being of the order of 10 μs at room temperature. The blue-green band (2.3–2.6 eV) is very much faster with r…
Porous silicon carbide has been fabricated using single crystal 6H-SiC that has a wider indirect band gap than silicon crystal. Intense blue-green luminescence has been observed at room temperature. The peak wavelength is around 460 nm, below the band gap of crystalline SiC. The luminescence intensity is about 100 tim…
We report here our discovery of bulk superconductivity at rather high ${\mathit{T}}_{\mathit{c}}$ in samples having nominal compositions ${\mathrm{YNi}}_{4}$${\mathrm{BO}}_{0.2}$ (${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}12.5 K) and ${\mathrm{YNi}}_{2}$${\mathrm{B}}_{3}$${\mathrm{O}}_{0.2}$ (${\mathit{T}}_{\ma…
Abstract To obtain poly(lactic acid) (PLA) complex fibers, spinning was performed by wet and dry methods from 5–10 g/dL chloroform solutions of poly(D‐lactic acid) (PDLA) and poly(L‐lactic), both with a viscosity‐average molecular weight of 3 × 10 5 . The dope was extruded from a monohole nozzle into coagulation baths…
Laser radiation (XeCl laser, 308-nanometer wavelength) focused into a cell containing Mo(CO)(6) vapor produced ultrafine particles in the extended waist of the laser beam. Negative ion mass spectrometry revealed molybdenum carbide cluster ions with a stoichiometry MonC4n (n = 1 to 4). The MonC4n(-) (n = 2 to 4) ions a…
The structural basis for the stability of N termini of helices has been analyzed by thermodynamic and crystallographic studies of three suitably engineered mutants of the barley chymotrypsin inhibitor 2 with Ser, Gly, or Ala at the N-cap position (residue 31). Each mutant has a well-organized shell of hydration of the…
The dense packing observed in protein interiors appears to be crucial for stabilizing the native structure--even subtle internal substitutions are usually destabilizing. Thus, steric complementarity of core residues is thought to be an important criterion for "inverse folding" predictive methods, which judge whether a…
We report direct measurements of force vs. separation between self-assembled proteins. These forces are observed between collagen triple helices in native and reconstituted fibers. They are a combination of a short-range repulsion, which varies exponentially over at least five decay lengths, and an inferred, longer-ra…
An investigation of low-frequency inelastic scattering (LOFIS) and pre-resonant Raman spectroscopy has revealed the role of the modifying cations, Ba 2+ , Zn 2+ and Pb 2+ on the bonding properties of the Eu-O bond in Ba(PO 3 ) 2 , Zn(PO 3 ) 2 , and Pb(PO 3 ) 2 glasses. Analysis of the results has shown that the electr…
Abstract The interaction of sulfur, ZnO, stearic acid, and the three sulfenamide accelerators N ‐cyclohexylbenzothiazole sulfenamide (CBS), 2‐(4‐morpholinothio) benzothiazole (MOR), and 2‐ t ‐butylaminobenzothiazole sulfenamide (TBBS) were investigated by differential scanning calorimetry in the absence of rubber. In…
Abstract The effects of corona‐discharge treatment (CDT) of commercial polyethylene (PE) Linear low‐density PE (LLDPE) were studied with special emphasis on the heat‐seal behavior of treated films. A range of treat levels, representative of those used in industry, was obtained by varying the applied power to a commerc…
Electron beams with an energy of 10 keV were employed for selectively poling only the lower part of a typical nonlinear optical guest/host polymer at a temperature of 90 °C. The resulting dipole orientation was examined by means of electro-optical measurements and thermally stimulated depolarization, while the nonunif…
Abstract The thermal decomposition of three sulfenamide accelerators N ‐cyclohexylbenzothiazole sulfenamide (CBS), 2‐(4‐morpholinothio) benzothiazole (MOR) and 2‐ t ‐butylaminobenzothiazole sulfenamide (TBBS) were investigated by differential scanning calorimetry. The sulfenamides decompose rapidly at 210–220°C, yield…
Abstract Series of polyurethaneurea elastomers were prepared from 4,4′‐diphenylmethane diisocyanate, poly(teuramethylene ether) glycol and poly(hexamethylene carbonate) glycol for mixed soft segments, and 1,4‐butanediol and isophoronediamine for mixed chain extenders. Characteristics of the copolymers related with com…
Abstract The characterization of short chain branching in polyethylene using transmission FTIR spectroscopy is investigated. Traditional methodologies, using the methyl deformation band for qualitative and quantitative analyses, have recognized shortcomings. The methyl and methylene rocking bands, which are more chara…
Abstract In this paper, the crystallization characteristics of polypropylene and low ethylene content polypropylene copolymers with and without nucleating agents were studied by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). In order to determine the nonisothermal crystallization rate of…
Abstract Heat sealing of films, i. e., formation of a joint between two films by placing them fleetingly between heated platens, was experimentally investigated for a variety of semicrystalline polyolefins, especially various polyethlenes, to determine how sealing temperature affected seal strength measured at room te…
The rare-earth gallium oxide perovskites RGaO 3 (R=La,Pr,Nd) are promising substrates for epitaxy of high-T c superconductors. In this paper the crystal structures of orthorhombic and rhombohedral RGaO 3 have been studied by neutron diffraction, which allows precise localization of light atoms such as oxygen, which ar…