Materials Literature
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Slime layers are being studied in our laboratories in an attempt to understand their functions in the control of pollution in natural streams. A method for fixing, staining, and embedding microorganisms in the intact slime has been developed. In this method, epoxy resin discs are placed in a holder and are introduced…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOne-electron oxidation of metalloporphyrinsJ. H. Fuhrhop and David MauzerallCite this: J. Am. Chem. Soc. 1969, 91, 15, 4174–4181Publication Date (Print):July 1, 1969Publication History Published online1 May 2002Published inissue 1 July 1969https://doi.org/10.1021/ja01043a027…
Abstract Starting with specific constitutive equations, methods of evaluating material properties from experimental data are outlined and then illustrated for some polymeric materials; these equations have been derived from thermodynamic principles, and are very similar to the Boltzmann superposition integral form of…
Crystal distortions in Cr associated with antiferromagnetic ordering have been established using electrical-resistance strain gauges. Between 123 and 311\ifmmode^\circ\else\textdegree\fi{}K the observations confirm the existence of an orthorhombic structure associated with the presence of a transversely polarized spin…
Striking evidence for a fundamental covalent-ionic transition in the electronic nature of solids is presented.
The tunneling splitting of the torsional-oscillator ground state of a hindered methyl group is taken into account in calculating the temperature dependence of the proton spin-lattice relaxation time. Thermal vibrations cause spin-independent transitions leading to a fluctuation in the sign of the splitting parameter.…
Using a light-beat laser spectrometer, we observe the relaxation of the thermally excited fluctuations of anisotropy in the nematic phase of $p\ensuremath{-}\mathrm{azoxyanisole}$. We identify the two low-frequency purely dissipative modes recently predicted. A first study of the angular dependence of the width of the…
An analog of proline, 2, 3-cis-3, 4-trans-3, 4-dihydroxy-L-proline, was found in the cell walls of the eight species of diatoms studied and was isolated from the proteinaceous material of the wall of Navicula pelliculosa. The properties of this substance are described; its structure was confirmed by nuclear magnetic r…
On the assumption that in Ni-Cu alloys the spin moment on a Ni atom depends on the local atomic environment, it was possible to find moment values for the various atomic configurations so as to give average moments in reasonable quantitative agreement with the values measured in the ferromagnetic composition range. Th…
The remarkable similarity of the $U$ band originating from the first electronic transition of the ${\mathrm{H}}^{\ensuremath{-}}$ or ${\mathrm{D}}^{\ensuremath{-}}$ centers in an alkali halide to the $F$ band in the corresponding alkali halide is pointed out. The band shape and phonon broadening of $U$ bands in alkali…
The thermal conductivity $K$ between 5 and 100\ifmmode^\circ\else\textdegree\fi{}K was measured on Te-doped samples with excess donor concentrations $n$ ranging between \ensuremath{\sim}${10}^{17}$ and 2\ifmmode\times\else\texttimes\fi{}${10}^{18}$ ${\mathrm{cm}}^{\ensuremath{-}3}$. At temperatures below that of the p…
The resistivities of condensed polycrystal and single-crystal aluminum films have been measured as a function of thickness (1600-36000 \AA{}) and temperature (4.2-300\ifmmode^\circ\else\textdegree\fi{}K). Both the temperature-independent residual resistivity and the temperature-dependent resistivity increase with decr…
Sc2O3 has been transformed at 1000°C and 130 kb from the relatively open C-rare-earth structure type to the monoclinic B-rare-earth form with unit cell dimensions α = 13.173 A, b = 3.194 A, c = 7.976 A, and β = 100.40°. The calculated density, 4.16 g/cm3, represents an increase of 8.3% over the density of C-type Sc2O3…
Phonon dispersion curves along the $[00\ensuremath{\zeta}]$, $[0\ensuremath{\zeta}1]$, $[0\ensuremath{\zeta}\ensuremath{\zeta}]$, and $[\ensuremath{\zeta}\ensuremath{\zeta}\ensuremath{\zeta}]$ directions in KCl at 115\ifmmode^\circ\else\textdegree\fi{}K have been measured by inelastic scattering of slow neutrons using…
An interpretation of the binding in the second-row diatomic hydrides NaH, MgH, AlH, SiH, PH, SH, and HCl is presented based on the molecular charge distributions and the forces exerted on the nuclei. The total density distributions are discussed in relation to “molecular” size and the arbitrary partitioning of the tot…
Infrared spectra in the region 4000–1300 cm −1 have been obtained of acetic acid, acetyl chloride, acetic anhydride, propionic acid, and propionyl chloride adsorbed on discs of pressed silica powder. In all cases the spectra showed the presence of both the simple hydrogen-bonded species[Formula: see text]where X = OH,…
It is shown that Nozières and de Dominicis's exact solution to Mahan's model x-ray problem may be obtained very simply using an equation-of-motion technique.Received 25 November 1968DOI:https://doi.org/10.1103/PhysRev.182.973©1969 American Physical Society
Excitation spectra of the D45 → 7F emission of Tb3+ were measured in Sc(or In) BO3, and Y (or Gd) BO3, Y3Ga5O12, Sc (or Y) PO4, and Sc2 (or Y2) O3 at room temperature. The 4f–5d excitation band is discriminated from the host lattice excitation band by inspecting the concentration dependences of the excitation spectra.…
Measurements of the nuclear spin-lattice relaxation rate $\frac{1}{{T}_{1}}$ for ${\mathrm{In}}^{115}$, ${\mathrm{Sb}}^{121}$, and ${\mathrm{Sb}}^{123}$ in $n$-type InSb at low temperatures (1.3-4.2\ifmmode^\circ\else\textdegree\fi{}K) are presented as a function of magnetic field $H$ and crystal orientation for sever…
Infrared reflectance and excitation measurements, together with studies of the dependence of the luminescence on excitation intensity and sensitizer concentration, in the fluorides of La, Gd, and Y doped with ${\mathrm{Yb}}^{3+}$ and ${\mathrm{Er}}^{3+}$, ${\mathrm{Ho}}^{3+}$, or ${\mathrm{Tm}}^{3+}$ indicate that inf…