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The self-consistent perturbation theory developed in an earlier paper is formulated more explicitly and applied to various types of perturbation: (i) one-element change of the one-electron Hamiltonian matrix (i.e., of Coulomb or resonance integral), (ii) uniform electric field, (iii) point charge near the system. The…
By varying light and temperature, differences in diurnal ring structure were produced in cotton fibers from inbred lines of Deltapine 14 and Rex 25C belonging to the species Gossypium hirsutum. The relationships of the secondary wall structure to physical and chemical properties were then investigated. When fibers wer…
Abstract Investigations of the dynamic cut growth behavior of vulcanized rubbers indicate that there is a minimum tearing energy at which mechanical rupture of chains occurs. The limiting value is characteristic of each vulcanizate, but is in the region of 0.05 kg/cm. The mechanical fatigue limit, below which the numb…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Six Trimethoxyphenylisopropylamines (Trimethoxyamphetamines)Alexander T. ShulginCite this: J. Med. Chem. 1966, 9, 3, 445–446Publication Date (Print):May 1, 1966Publication History Published online1 May 2002Published inissue 1 May 1966https://pubs.acs.org/doi/10.1021/jm00…
Abstract The rate of growth of bubbles forming on a wall from a liquid initially uniformly supersaturated with a dissolved gas was investigated. Attention was directed to the effect of the contact angle. Theoretical predictions for the growth rate of a spherical bubble tangent to a wall were carried out with a digital…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared Absorption Spectra of Inorganic Solids. IV. Hexafluorosilicates. Raman Spectra of Aqueous SiF62-R. B. Badachhape, G. Hunter, L. D. McCory, and J. L. MargraveCite this: Inorg. Chem. 1966, 5, 5, 929–931Publication Date (Print):May 1, 1966Publication History Published…
A large glass‐forming region was discovered in the system EUO–Al 2 O 3 –B 2 O 3 and chemically stable glasses of good optical quality were produced. The concentration range extends from about 3 to 43 mole % EuO. Room‐temperature Verdet constants as large as –2.55 min/oe‐cm were measured on a glass containing 30.5 mole…
Abstract The temperature dependence of abrasion of various gum and black-filled rubbers on silicon carbide paper is closely similar to the temperature dependence of their energy density at break determined at a high rate of extension. The conclusion is drawn that this type of abrasion is predominantly due to tensile f…
Abstract Four clays were treated with each of eight surfactants at three treatment rates. Volclay and the clay fraction from two montmorillonitic soils were treated with 100, 50, and 10 mmol /100 g.; and kaolinite was treated with 10, 5, and 1 mmol /100g. Adsorption was measured quantitatively by the thermogravimetric…
The permeability to oxygen of 4 wt% lime‐stabilized zirconia and hafnia and of pure thoria was determined between 1100° and 2050°C. The permeability constant (permeability multiplied by the thickness) at 25 torr oxygen pressure is given by: image A 1/4‐power oxygen pressure dependence of the permeability was found for…
Single crystals of γ-LiBO2, which is the phase stable at high (P, T), have been grown at 15 kbar and at 950°C by using a flux technique. The crystals were retained metastably by quenching to room pressure and temperature. γ-LiBO2 is tetragonal with four molecules per unit cell (a=4.1961±0.0004, c=6.5112±0.0007 Å), Spa…
With a new technique of negative staining of sections, it has been possible to observe directly, in ultrathin sections under the electron microscope, the original microcrystalline and microfibrillar structure of cellulose as it occurs in living cells. This method has advantages over the study of isolated fibers used s…
New data on the density of B2O3 from 25° to 230°C are given. A two-state equation of state for the volume is presented which fits the volume data from 350° to 1400°C. A specific structure for the two states is suggested and shown to be consistent with Raman data. Below 350°C and at high pressures the data indicated th…
Self‐diffusion of Zr in 12 and 16 mol.% CaO and of Ca in 16 mol.% CaO cubic zirconia was measured by the sectioning technique from 1700° to 2150°C. Lattice self‐diffusion coefficients are: image Autoradiographs show rapid grain boundary diffusion. D B is estimated as <10 5 D L between 1800° and 2150°C. The low cati…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation of Hot OH Bonds in the Radiationless Relaxations of Excited Rare Earth Ions in Aqueous SolutionsAdam HellerCite this: J. Am. Chem. Soc. 1966, 88, 9, 2058–2059Publication Date (Print):May 1, 1966Publication History Published online1 May 2002Published inissue 1 May 1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMass Spectrometric Characterization of Petroporphyrins1Earl W. BakerCite this: J. Am. Chem. Soc. 1966, 88, 10, 2311–2315Publication Date (Print):May 1, 1966Publication History Published online1 May 2002Published inissue 1 May 1966https://pubs.acs.org/doi/10.1021/ja00962a040h…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal Structure of the Rhombohedral MO3.3R2O3 Compounds (M = U, W, or Mo) and Their Relation to Ordered R7O12 PhasesS. F. BartramCite this: Inorg. Chem. 1966, 5, 5, 749–754Publication Date (Print):May 1, 1966Publication History Published online1 May 2002Published inissue 1…
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
The indices of refraction of ADP, KDP, and deuterated KDP were measured at temperatures between the Curie point and room temperature. The estimated accuracy of the data is ±0.0001. The empirical equation Δn = (n2+an+b)c(298 − T) where n is the index at room temperature, Δn is the change in index, and T is the temperat…
Single-crystal specimens or polycrystalline sinters of cubic NaCl, KCl, KBr, KI, MgO, CaO, NiO, UC, CaF 2 , BaF 2 , UO 2 , and ThO 2 as well as anisotropic TiO 2 , Al 2 O 3 , and U 3 O 8 were bombarded with 40-keV xenon or krypton ions to give integrated ion doses of up to 2 × 10 16 ions/cm 2 . The specimens were exam…