Materials Literature
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A polymethyl methacrylate insulator rod in vacuum is stressed by high-voltage pulses having 3-ns rise times, with the result that 40-mm-long incomplete discharges occur at the end of the rod. Time-resolved measurements of electron emission from different areas on the insulator surface indicate that a discharge propaga…
The photoelectron spectra of PbCl 2 , PbBr 2 and SnCl 2 , which have the lead chloride-type crystal structure, have been measured with X-rays and extreme ultraviolet rays in order to investigate the electronic structures of their valence bands. The photoelectron spectra of TlCl and Pbl 2 have also been measured for co…
The dielectric properties of polydimethylsiloxane fluids have been investigated under dc and ac fields as a function of field, frequency, temperature, and water content. The results of the ac studies have shown that the dielectric constant and dielectric loss of the fluid exhibit several transitions as a function of t…
A scaling theory is proposed for solids under hydrostatic pressures which do not undergo structural phase transitions or symmetry distortions or for which distortions may be neglected. The theory is tested with two adjustable parameters by computing the linear frequency shifts (dν/dP) for the optical transitions 4A2(F…
A development of a conic fitting procedure is described which enables the X-ray source point in Kossel diffraction to be determined solely by analysis of shadows cast on the recording film and so dispenses, in subsequent analysis of the pattern, with the need to have prior knowledge of the crystal structure of the spe…
NRC publication: Yes
There is an ever increasing interest in studying electrical conduction and polarization phenomena in polymers. This is partly due to the increasing application of plastics in the electric and electronic industry, partly to the close connection between electric, magnetic and mechanical relaxation phenomena. It is becom…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUnusual electron-transfer processes involving electron-rich and electron-deficient metallocenesJohn D. L. Holloway, William L. Bowden, and William E. Geiger Jr.Cite this: J. Am. Chem. Soc. 1977, 99, 21, 7089–7090Publication Date (Print):October 1, 1977Publication History Pub…
Abstract The electronic band structure of systems with screw symmetry is developed using the smallest screw displacement as elementary operation. For atomic and molecular helical systems the resulting Hartree‐Fock SCF‐LCAO formulae are presented. Results for ferroelectric HC1 and HP are reported, obtained with the MUN…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitrosylmetalloporphyrins. 4. Molecular stereochemistry of two crystalline forms of nitrosyl-.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinato(4-methylpiperidine)iron(II). A structural correlation with .nu.(NO)W. Robert Scheidt, A. Chris Brinegar, E. B. Ferro, and John F.…
Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML ...Read More
The results of the published work on the high pressure-high temperature properties of the AB-type compounds have been compiled and evaluated. All pressure studies above the range of 1 kilobar have been included with an emphasis on the accurate characterization of the solid-solid phase boundaries and the experimental m…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of a very small piece of silver metal. The octahedral silver (Ag6) molecule. Two crystal structures of partially decomposed vacuum-dehydrated fully silver(1+) ion-exchanged zeolite AYang Kim and Karl SeffCite this: J. Am. Chem. Soc. 1977, 99, 21, 7055–7057Publicati…
Impression creep tests of LiF single crystals at 600–750[ddot]C and under punching stresses of 4-30 MN/m2 are reported. Both temperature and stress dependences are comparable with those of conventional compression creep tests under similar conditions. These dependences give a power law stress exponent of 4–5 and an ac…
An x-ray diffraction study of Nylon 11 was carried out at high pressures and high temperatures. Careful measurements made on both wet and dry samples at atmospheric pressure indicated that the structure of Nylon 11 suggested by Slichter was not quite correct. Some distortion of the planar conformation causes a shorten…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHomoenolate anion precursor. Reaction of ester homoenol silyl ether with carbonyl compoundsEiichi Nakamura and Isao KuwajimaCite this: J. Am. Chem. Soc. 1977, 99, 22, 7360–7362Publication Date (Print):October 1, 1977Publication History Published online1 May 2002Published ini…
The theory of exchange narrowing is extended in systems with large isotropic ${J}_{0}$ to include static spin correlations and antisymmetric exchange. Both contribute to the unusual temperature-dependent, exchange-narrowed EPR linewidth $\ensuremath{\Delta}H(T)$ in $\mathrm{Cu}X_{4}^{}{}_{}{}^{2\ensuremath{-}} (X=\mat…
Relaxation of excited electronic states of rare-earth ions by multiphonon emission was investigated in a beryllium-fluoride glass. Decay rates were measured from the transient fluorescence following pulsed laser excitation of selected states. The multiphonon emission rates exhibit an approximately exponential dependen…
Late during sporulation, Bacillus subtilis produces glucose dehydrogenase (GlcDH; EC 1.1.1.47), which can react with D-glucose or 2-deoxy-D-glucose and can use nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP) as a cofactor. This enzyme is found mainly in the forespore compa…
Structure-property relationships were investigated for blends of grafted rubbery polymers with PVC. Increasing grafting levels as well as higher blending temperatures improved the dispersion of the graft copolymers in PVC, lowered the impact strength, and reduced stress whitening. Presuming a mechanistic connection be…