Tourmaline as a petrogenetic indicator mineral - An example from the staurolite-grade metapelites of NW Maine
Tourmaline, a mineral often overlooked in petrological studies, is shown to be a useful petrogenetic indicator mineral.-J.A.Z.
Materials Literature
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X-ray optics of surfaces (reflection and diffraction at grazing angles of incidence)
A new direction in the field of x-ray optics is discussed. This new direction is associated with diffraction at grazing angles of incidence and diffraction; it is associated with the excitation of x-ray surface waves and quasiwaveguide modes, and with the study of the angular and energy dependences of the reflection s…
Influence of structure defects on the internal optical strength of KDP single crystals
Influence of structure defects on the internal optical strength of KDP single crystals, V V Azarov, L V Atroshchenko, Yu K Danileĭko, M I Kolybaeva, Yu P Minaev, V N Nikolaev, A V Sidorin, B I Zakharkin
Determination of the structure of the orthorhombic commensurate superlattice state of 2H-TaSe2by convergent-beam electron diffraction
Based on the analysis of higher-order Laue zone diffraction by Bird (1985), the structure of the commensurate superlattice state of 2H-TaSe 2 is determined by convergent-beam electron diffraction. It is shown that the most general displacements allowed by the orthorhombic space group can be described by a set of displ…
Science of Armour Materials
This article discusses some basic principles that underlie design of effective armour materials against various modes of attack.
Threshold Double Photoexcitation of Argon with Synchrotron Radiation
Auger satellites have been measured to determine the probability of $M$-shell excitation accompanying $K$-shell photoionization of Ar, as a function of photon energy. The theoretically predicted difference between the dependence of shakeup and shakeoff probabilities on the photon energy near threshold is demonstrated…
Nonexponential Relaxation of Conductance near Semiconductor Interfaces
Photoinduced excess charge at a GaAs interface barrier relaxes nonexponentially. A fit to experiment with a statistically motivated Kohlrausch formula is possible but unjustified. Serial relaxation by hierarchies of systems with increasing spatial separation of carriers furnishes a convincing explanation and exemplifi…
Radiation damage of NaCl: dose rate effects
The authors discuss the experimental results on radiation damage of NaCl single crystals in terms of the Jain-Lidiard model. This model has been improved by taking into account the back reaction between F centres and Cl 2 molecules. It appears that with this extended Jain-Lidiard model they can describe quantitatively…
High-temperature X-ray diffraction study on Co75Sn25 alloy
A high-temperature X-ray diffraction study on a Co75Sn25 alloy reveals it as a mixture of two phases, the f.c.c. solid solution β-Co(Sn) and the intermetallic phase γ-Co3Sn2. The lattice parameters of β-Co(Sn) and of γ-Co3Sn2 in the two-phase alloy Co75Sn25 are determined within the temperature range from 500 to 1050…
A new form of SnO2 found during oxidation of α-SnO thin films
The oxidation of tin-oxide thin films is studied by electron microscopy and diffraction. Cassiterite, the rutile-like form of SnO2, is formed during oxidation of amorphous films deposited on the carbon precoated substrates, while a new form of SnO2 with the structure of brookite is obtained if the epitaxial films of α…
Near Resonant Raman Scattering in NaNO2
Near resonant Raman scattering in highly purified NaNO 2 crystal has been investigated in changing the exciting photon energy ν i in the region near the zero-phonon line at ν 00 of the singlet absorption. A significant change in the scattering due to ν 2 vibration of NO 2 - in b ( a , a )\bar b configuration occurs as…
Thermally stimulated currents from corona-charged polypropylene films: A thermal effect of vacuum deposition of metallic electrodes
It is demonstrated that the thermally stimulated currents (TSC) from positively or negatively corona-charged polypropylene strongly depend on the order of the following two processes: a process of vacuum deposition of Al electrodes on the sample polymer and a process of heat-treatment of the polymer. Observed results…
Influence of the surface interaction on threshold values in the cholesteric-nematic phase transition
The threshold values for the field-induced cholesteric to nematic phase transition are described as crossover points of the free energy levels of the textures concerned. Known expressions for these energy levels as a function of an electric field are extended with a surface interaction term. By interpretation of exper…
Chemical-state studies of Zr and Nb surfaces exposed to hydrogen ions
Surface chemical states were studied for Zr and Nb metals exposed to 8-keV hydrogen molecular ions. X-ray photoemission spectroscopy (XPS) measurements revealed that chemical shifts of the binding energies for the ion-implanted Zr from the metallic states are 0.6--1.4 eV, consistent with the core-line shifts for therm…
Low-temperature behavior of potassium and sodium silicate glasses
In a study of the low-temperature anomalies which appear in disordered solids we have measured the specific heat, thermal conductivity, thermal expansion, and dielectric dispersion for a carefully prepared series of (${\mathrm{SiO}}_{2}$${)}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$(${\mathrm{K}}_{2}$O${)}_{\mathrm{x}}$ a…
Alignment of nematic liquid crystals by inhomogeneous surfaces
Variable oblique alignment of nematic liquid crystals has been achieved on microscopically inhomogeneous surfaces. The surfaces consist of small patches favoring vertical (homeotropic) alignment surrounded by a matrix favoring a planar alignment. The construction of these surfaces employs randomly distributed microsco…
Density fluctuations, dynamic light scattering, longitudinal compliance, and stress modulus in a viscoelastic medium
Correct relations between the dynamic light scattering spectrum and the mechanical creep compliance and longitudinal stress modulus of a viscoelastic liquid are provided. Analysis of the effect of temperature fluctuations on the longitudinal stress modulus is also given. The result provides a basis for determination o…
Interpretation of diffuse low-energy electron diffraction intensities
It is shown that the diffuse low-energy electron diffraction (LEED) that occurs between sharp LEED beams can be used to determine the local bonding configuration near disordered surface atoms. Two approaches to the calculation of diffuse LEED intensities are presented for the case of lattice-gas disorder of an adsorba…
Gauging film thickness: A comparison of an x-ray diffraction technique with Rutherford backscattering spectrometry
An x-ray diffraction technique for determining thin-film thickness is presented which should prove to be a valuable alternative to the array of spectroscopies (Rutherford backscattering spectrometry, Auger electron spectroscopy, etc.) currently favored for these measurements. Some of the virtues of this x-ray diffract…
Calorimetric studies of the binding of Streptomyces subtilisin inhibitor to subtilisin of Bacillus subtilis strain N'
The binding of Streptomyces subtilisin inhibitor (SSI) to subtilisin of Bacillus subtilis strain N' (subtilisin BPN', EC 3.4.21.14) was studied by isothermal calorimetry at pH 7.0 and at various temperatures ranging from 5 to 30 degrees C. Thermodynamic quantities for the binding reaction were derived as a function of…