Observation of Tunable Optical Parametric Fluorescence
Optical fluorescence, thermally tunable over significant portion of visible and near IR SPECTRUM, from phase-matched parametric system
Materials Literature
文献浏览
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Introduction to Nuclear Reactor Theory
"Introduction to Nuclear Reactor Theory." Nuclear Science and Engineering, 28(2), pp. 313–314
Hexagonal Diamond—A New Form of Carbon
A new crystalline form of carbon—hexagonal diamond—has been synthesized in the laboratory under conditions of static pressure exceeding about 130 kbar and temperature greater than about 1000°C. It is necessary to start with well-crystallized graphite in which the c axes of the crystallites are parallel to each other a…
Mössbauer Analysis of Iron in Clay Minerals
Mössbauer absorption spectrography can be used to establish the presence of Fe(2)+ and Fe(3)+ in clay minerals. In the sheet structure silicates, octahedrally coordinated iron can be distinguished from tetrahedrally coordinated iron. Siderite and goethite, common contaminants of the clay minerals, can usually be detec…
Chemical Exfoliation of Vermiculite and the Production of Colloidal Dispersions
Chemical treatments involving ion exchange cause gross onedimensional swelling in water of single crystals of vermiculite minerals. A delicate balance of forces holds the individual silicate layers (10 angstroms thick) parallel to one another although separated by several hundred angstroms. Colloidal dispersions produ…
Relationship between chemical structure and biological activity of hen egg-white lysozyme and lysozymes of different species
Abstract Fleming discovered an enzyme which he called lysozyme; it had ‘the power of rapidly dissolving certain bacteria, which is possessed by many animal and vegetable tissues and secretions and to a very marked degree by egg-white' (Fleming 1922). Hen egg-white lysozyme was crystallized by Abraham & Robinson in…
Crystallographic studies of the activity of hen egg-white lysozyme
Abstract The chemical evidence for the enzymic activity of lysozyme will be discussed in detail by other speakers at this meeting, but in order to describe our crystallographic studies of the interactions between the enzyme and its substrates it is necessary to summarize briefly what was known about them at the beginn…
Infrared Lattice Vibrational Spectra of AgCl, AgBr, and AgI
The infrared transmission spectra of AgCl, AgBr, and AgI have been measured between 400–30 cm−1 at room temperature and at 143°K. Strong absorptions characteristic of the transverse optic modes were found, together with weak subsidiary absorptions arising from multiphonon combinations. The longitudinal optic modes of…
Spontaneous decarboxylation of oxalacetic acid
The kinetic study at different pH values indicates that the monoanion of oxalacetic acid is the major active species which decarboxylates spontaneously. The decarboxylation of the monoanion is favored by nonpolar solvents. Solvent and isotopic effects suggest that the reaction may proceed via an intramolecular hydroge…
First and Second Sound in Crystals
A semiphenomenological theory for pure, insulating Bravais lattices is developed to clarify in a unified fashion the problems of sound propagation, sound damping, second sound, and heat conduction. The crystal is described as a gas of interacting quasiparticles coupled to an anisotropic elastic medium. The thermodynam…
Vacancy Clusters inα-Iron
A mathematical lattice model was used to compute the kinetic and static aspects of vacancy-cluster nucleation, growth, and dissociation in $\ensuremath{\alpha}$-iron. Persistent attention is paid to the kinetics of changes among metastable configurations as well as the formation of stable configurations. The tetravaca…
CRITICAL THICKNESS AND PERPENDICULAR ANISOTROPY OF EVAPORATED PERMALLOY FILMS WITH STRIPE DOMAINS
We report that the critical thickness for the appearance of stripe domains in evaporated permalloy films depends sensitively on vacuum pressure during evaporation and also that the perpendicular anisotropy constant can be obtained from the critical thickness rather precisely. It was found that the perpendicular anisot…
Effect of Boundaries and Isotopes on the Thermal Conductivity of LiF
In order to test thermal-transport theories with data involving readily calculable phonon scattering rates, the thermal conductivity of LiF has been measured between 1 and 100\ifmmode^\circ\else\textdegree\fi{}K, first for a series of isotopically pure crystals with sandblasted surfaces ranging in mean width from 1 to…
Equilibrium Approach to Second Sound in Solids
In the Boltzmann-equation derivation, second sound is seen as the self-sustained propagation of a temperature wave, assuming the establishment of local equilibrium. Kwok and Martin have shown, by a study of the linear response to a fluctuating displacement field, that second sound occurs as an elementary excitation. I…
Sensitivity of Curie Temperature to Crystal-Field Anisotropy. I. Theory
This paper discusses the statistical mechanics of ferromagnetic and antiferromagnetic systems in the presence of uniaxial anisotropy, which is included both as anisotropic exchange ${D}_{\mathrm{ij}}S_{i}^{}{}_{}{}^{z}S_{j}^{}{}_{}{}^{z}$ and in the form of single-ion crystal-field terms ${D}_{0}{(S_{i}^{}{}_{}{}^{z})…
Selective Excitation and Decay ofEr3+Fluorescence in LaF3
A simple treatment of pulsed and steady-state selective-excitation experiments in multilevel systems is given and used to interpret the fluorescence excitation and decay properties of ${\mathrm{Er}}^{3+}$ in La${\mathrm{F}}_{3}$. Fluorescence from eight different excited states was studied. From excitation spectra and…
Cation-Cation Interaction Contributions to the Hyperfine Interaction. The "Supertransferred Hyperfine Interaction"
The change in hyperfine field at a central cation site when the nearest-neighbor cation sites are occupied by magnetic ions is calculated. Two mechanisms dominate this effect: one an orthogonalization of the neighboring magnetic ion's $\ensuremath{\sigma}$ orbitals to the inner $s$ shells of the central cation; the ot…
Galvanomagnetic Effects in Iron Whiskers
Measurements have been made of the temperature dependence of the Hall effect in the range 1-300\ifmmode^\circ\else\textdegree\fi{}K, and of the transverse and longitudinal magnetoresistance at low temperatures, in [100] and [111] iron whiskers of high purity (resistance ratios extrapolated to $B=0$ ranged from 242 to…
Drilling String Corrosion - A Major Drilling Problem
Abstract The sources of drilling string corrosion are discussed, together with an economic estimate of the magnitude of this problem in our drilling industry. Problems associated with measuring the corrosion rate in drilling fluids under field conditions are reviewed. A technique for making corrosion rate evaluations…
Verfahren zur Schwingungsbehandlung von Metall‐ und Stahlschmelzen unter besonderer Berücksichtigung der Kornfeinung durch Erstarrungsbeschallung
Möglichkeiten zur Verfeinerung von Gußgefüge durch Schwingungsbehandlung der erstarrenden Schmelze. Versuche mit der Erstarrungsbeschallung an Zinn, Zink und Aluminium. Schwingungsbehandlung von Stahl beim Vakuum‐Lichtbogenschmelzen, beim Elektroschlackeschmelzen, beim Stranggießen und beim Sauerstoffaufblas‐Verfahren.