Materials Literature
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An equation is d eveloped to gi ve pit d epth as a fun ction of collision velocity for pits formed in soft to medium-hard metal plates as a r esul t of collision with liquid dro ps. The rear face of t he target plate must be a free surface. The plate t h ickness must not be less t han 1.5 to 2.0 tim es the drop diamet…
Pertinent works of previous investigators are reviewed briefly. A superior technique for the preparation of experimental glasses of high purity and chemical homogeneity is presented. Devitrification growth‐rate data and traction‐viscosity data are reported for high‐silica glasses of the system Al 2 O 3 ‐SiO 2 . Glasse…
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.
Abstract Under conditions of vacuum pyrolysis, the rate of weight loss of dimethylpolysiloxanes varies from one sample to the next in an apparently random fashion. This variation is attributed to catalyzed chain cleavage brought about by trace impurities.
I n meas uring the rates of thermal degradation of polym e rs at constant tempe rat u res in the r ange of 200 0 to 500 0 C, one encoun ters a distortion of t he initial p arts of t he rate cur ves during the time required to h eat the sp ecimen to t he p yrolys is tempe raL ure . This distortion has been largely over…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Structure of Certain Polyazaindenes. II. The Product from Ethyl Acetoacetate and 3-Amino-1,2,4-triazoleC. F. H. ALLEN, H. R. BEILFUSS, D. M. BURNESS, G. A. REYNOLDS, J. F. TINKER, and J. A. VanALLANCite this: J. Org. Chem. 1959, 24, 6, 787–793Publication Date (Print):Jun…
The thermal expansion characteristics of polycrystalline 〈UN〉, 〈UO2〉, 〈UO2·ThO2〉 solid solution, and 〈ThO2〉 were determined between room temperature and ca 1000°C by means of x-ray diffraction techniques. For the range 26° to 1000°C, the values of the average linear thermal expansion coefficients (ᾱ×106/∘C) are 8.61,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Cyclobutanes. I. Synthesis of MethylenecyclobutanesH. N. Cripps, J. K. Williams, and W. H. SharkeyCite this: J. Am. Chem. Soc. 1959, 81, 11, 2723–2728Publication Date (Print):June 1, 1959Publication History Published online1 May 2002Published inissue 1 June 1959…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNotes: Preparation of PyrroleJohn Patterson and Peter DrenchkoCite this: J. Org. Chem. 1959, 24, 6, 878–879Publication Date (Print):June 1, 1959Publication History Published online10 July 2003Published inissue 1 June 1959https://pubs.acs.org/doi/10.1021/jo01088a621https://do…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Chemistry of Borazene. II. The Synthesis of N-Trimethyl-B-trialkoxyborazenes and N-Trimethyl-B-triphenoxyborazene1Mildred J. Bradley, George E. Ryschkewitsch, and Harry H. SislerCite this: J. Am. Chem. Soc. 1959, 81, 11, 2635–2638Publication Date (Print):June 1, 1959Publ…
Dehydration of thiodiglycol at 195°–230° with potassium hydroxide produced a 36% yield of divinyl sulphide, 9–10% of 2-methyl-1,3-thioxolane, 7–8% of 1,4-thioxane, and 3.5% of vinyl 2-hydroxyethyl sulphide. Physical properties and infrared spectra are reported. Divinyl sulphide of high purity for polymer work was obta…
This paper is restricted to a review of the work carried out in order to develop a strain gauge capable of operating at temperatures up to 1000°C with an inherent accuracy of ±5 per cent. A large number of resistance alloys were tested as unbonded long wires at room temperature and, from the results obtained, a small…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEpoxyorganosiloxanesE. P. Plueddemann and G. FangerCite this: J. Am. Chem. Soc. 1959, 81, 11, 2632–2635Publication Date (Print):June 1, 1959Publication History Published online1 May 2002Published inissue 1 June 1959https://pubs.acs.org/doi/10.1021/ja01520a008https://doi.org/…
Li${\mathrm{H}}_{3}$${(\mathrm{S}\mathrm{e}{\mathrm{O}}_{3})}_{2}$ crystallizes in the monoclinic system and exhibits useful ferroelectric properties in the entire temperature range -196\ifmmode^\circ\else\textdegree\fi{}C to 90\ifmmode^\circ\else\textdegree\fi{}C. The spontaneous polarization and coercive field at ro…
Approximate wave functions for the hydrogen molecule ground state previously available in the literature are analyzed quantitatively into approximate natural spin orbital functions with particular attention to the corresponding occupation numbers. The analysis demonstrates the very great similarity of all such trial w…
The conditions for preparing evaporated Al films of highest reflectance for mirrors and gratings to be used in the vacuum ultraviolet are summarized, and an account is given of aging studies. The preparation of bloom-free, one-micron thick coatings for grating blanks is described, and the effect of thin overcoatings o…
The general treatment developed in previous papers is applied to the case where the aqueous solution of polyvinyl alcohol is irradiated by gamma rays and the results are compared with Danno's measurements. The behaviours of irradiated aqueous solution of polyvinyl alcohol before and after gelation are well explained b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory of Agar Diffusion Methods for BioassayR. K. FinnCite this: Anal. Chem. 1959, 31, 6, 975–977Publication Date (Print):June 1, 1959Publication History Published online1 May 2002Published inissue 1 June 1959https://pubs.acs.org/doi/10.1021/ac60150a040https://doi.org/10.10…
Saturation of thc microwave electron paramagnetic resonance of impurities in various materials produces enhanced and reversed nuclear polarization throughout the material. This effect was investigated and is discussed in some detail for LiF single crystals. Results for other materials at microwave frequencies between…
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.