Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTObservations by high-resolution carbon-13 nuclear magnetic resonance of cellulose I related to morphology and crystal structureWilliam L. Earl and D. L. VanderHartCite this: Macromolecules 1981, 14, 3, 570–574Publication Date (Print):May 1, 1981Publication History Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSuperconductivity in an organic solid. Synthesis, structure, and conductivity of bis(tetramethyltetraselenafulvalenium) perchlorate, (TMTSF)2ClO4K. Bechgaard, K. Carneiro, F. B. Rasmussen, M. Olsen, G. Rindorf, C. S. Jacobsen, H. J. Pedersen, and J. C. ScottCite this: J. Am.…
We studied the adsorption properties of plasma fibronectin (pFN) on wettable tissue culture (TC) dishes and nonwettable bacteriological (BAC-T) dishes in relationship to its biological activity of promoting fibroblast spreading. The binding of pFN to the dish surfaces was found to be very tight and partially resistant…
Previous research toward more efficient nonlinear optical organic crystals has aimed at increasing the first-order hyperpolarizabilitiy of individual molecular units. We show that the general features derived from these studies (high conjugation, charge transfer, and molecular asymmetry) leave room for the cancellatio…
Accurate core level binding energies for the L and M shells in the metals 22 Ti to 30 Zn have been measured by means of ESCA. Comparisons with previously reported data in many cases show discrepancies of several eV. The spin-orbit splittings of the 2 p subshells have been measured with high accuracy and are compared w…
Abstract The hydrolytic degradation of polyglycolic acid (PGA) was studied by examining the changes of tensile strength and the level of crystallinity of the suture material. It was found that the breaking stress decreased from 6.369 × 10 −1 at 0 day to 3.97 × 10 −3 Newton/Tex at 49 days. The sigmodial shape of the st…
Peaks in the ultrasonic attenuation observed in amorphous materials are almost always explained in terms of a classical, thermally activated, structural relaxation process represented by a symmetric double-well potential with a broad distribution of barrier heights. This model suffers from two drawbacks: a low barrier…
Abstract Ultradrawing of films of high‐molecular‐weight polyethylene (M̄ w = 1.5 × 10 6 ) produced by gelation crystallization from solution is discussed. The influence of the initial polymer volume fraction (ϕ) on the maximum draw ratio (λ max ) of the dried films is examined in the temperature region from 90–130°C.…
Two-dimensional NMR techniques which sep. the chem. shift and heteronuclear dipolar interactions were applied to samples spinning at the magic angle. Because of the inhomogeneous nature of the 2 interactions, rotational echoes were obsd. in the time domain of each dimension. The corresponding Fourier transforms yield…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDegree of charge transfer in organic conductors by infrared absorption spectroscopyJ. S. Chappell, A. N. Bloch, W. A. Bryden, M. Maxfield, T. O. Poehler, and D. O. CowanCite this: J. Am. Chem. Soc. 1981, 103, 9, 2442–2443Publication Date (Print):May 1, 1981Publication Histor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-valent iron-porphyrin complexes related to peroxidase and cytochrome P-450John T. Groves, Robert C. Haushalter, Mikio Nakamura, Thomas E. Nemo, and B. J. EvansCite this: J. Am. Chem. Soc. 1981, 103, 10, 2884–2886Publication Date (Print):May 1, 1981Publication History Pu…
The satellite structure of core photoelectron and Auger lines of the copper dihalides are explained in terms of final-state energies diminished by Coulomb interactions between the valence electrons and the created core hole or holes. The satellite structure in the $3p$ and valence-band photoelectron spectra are shown…
A noncytotoxic dose of verapamil, a coronary vasodilator, enhances the cytotoxicity of vincristine (VCR) and vinblastine in P388 leukemia and its VCR-resistant subline, P388/VCR. When 2.2 to 6.6 microM verapamil was added along the VCR to the P388/VCR culture in vitro, VCR resistance was completely overcome. Verapamil…
An experiment is described in which a synthetic diamond containing a high concentration of dispersed nitrogen atoms was heated at 2400 degrees C and 2500 degrees C under a stabilising pressure of about 9.5 GPa. The nitrogen atoms aggregated to form the types of nitrogen centres which are found in natural type 1a diamo…
The thermal conductivity and specific heat of epoxy-resin samples made from Epikote 828 resin wth Epikure NMA hardener has been measured from 0.1 to 80K. The samples were produced under various curing conditions. Normally-cured samples (Cure N)-2 h at 100 degrees C followed by 4 h at 200 degrees C; cure A-36 h at 66 d…
For pt.I see ibid., vol.12, p.5393 (1979). A programme of elastic neutron-diffraction experiments has been undertaken to derive (and compare) atomic distribution functions, with high spatial resolution, for the ABX 3 antiferroelectric perovskites SrTiO 3 , KMnF 3 , RbCaF 3 and CsPbCl 3 in their cubic phase. The backgr…
The model of human Fc fragment was refined at 2.9-A resolution. Two different automated procedures for crystallographic refinement were used [Deisenhofer, J., & Steigemann, W. (1975) Acta Crystallogr., Sec. B B31, 238; Jack, A., & Levitt, M. (1978) Acta Crystallogr., Sect. A A34, 931]. The final R value is 0.22. The d…
Polarized reflectance measurements from the far infrared to the visible are reported for ${(\mathrm{TMTSF})}_{2}$P${\mathrm{F}}_{6}$. At low temperatures, both parallel and perpendicular polarizations show plasma edges in the infrared with metallic reflection below these edges, indicating two- or three-dimensional beh…
Structural phase transitions in K 2 CO 3 have been investigated using light scattering techniques. The Raman spectrum of the high-temperature hexagonal phase consists of a very broad structureless band which suggests that the system is highly anharmonic. Below the hexagonal-monoclinic transition at T cl =693K the auth…
Powdered and single crystal specimens of dysprosium manganate, DyMn 2 O 5 , have been studied by neutron diffraction at temperatures between ambient and 4.2K. Magnetic transitions are observed at 44K, 18K and 8.4K. Both manganese and dysprosium moments are ordered below 8.4K, where the magnetic structure has been refi…