Color Centers in Additively Colored CsBr

Color centers have been studied in CsBr single crystals additively colored with potassium or cesium. More than ten absorption bands were produced, most of which had previously been found in crystals colored by ionizing radiation. All bands produced by irradiation at or above liquid nitrogen temperature appear to arise from trapped electrons. The most prominent bands in the additively colored crystals are the F band at 642 mμ (liquid nitrogen temperature) and a band at 243 mμ which appears to be due to an impurity. Optically bleaching the F band at 200°K produces bands analogous to the M and R bands in other alkali halides while bleaching at liquid nitrogen temperature yields a broad band identified as the F′ band. Evidence that the asymmetry of the F band arises from several states of the F center is presented

Tantalus, a 240MeV Dedicated Source of Synchrotron Radiation, 1968-1986

Tantalus was a 240 MeV electron storage ring completed and commissioned in 1968. It was the first storage ring operated exclusively for the production of synchrotron radiation, although it was not designed for that purpose. As such, it influenced the operating pattern for subsequent dedicated sources of synchrotron radiation. Pioneering experiments using synchrotron radiation were carried out on this machine, and innovative instrumentation was produced there. It ceased operation in 1986

Pseudoeurycea unguidentis

Number of Pages: 2Integrative BiologyGeological Science

Pseudoeurycea longicauda

Number of Pages: 2Integrative BiologyGeological Science

The Wister Mud Pot Lineament: Southeastward Extension or Abandoned Strand of the San Andreas Fault?

We present the results of a survey of mud pots in the Wister Unit of the Imperial Wildlife Area. Thirty-three mud pots, pot clusters, or related geothermal vents (hundreds of pots in all) were identified, and most were found to cluster along a northwest-trending line that is more or less coincident with the postulated Sand Hills fault. An extrapolation of the trace of the San Andreas fault southeastward from its accepted terminus north of Bombay Beach very nearly coincides with the mud pot lineament and may represent a surface manifestation of the San Andreas fault southeast of the Salton Sea. Additionally, a recent survey of vents near Mullet Island in the Salton Sea revealed eight areas along a northwest-striking line where gas was bubbling up through the water and in two cases hot mud and water were being violently ejected

Behavioral Aspects of Pricing

Buyers sometimes exhibit seemingly “irrational” behavior with respect to prices and use socially embedded heuristics to simplify their purchase decisions. In some cases small changes in prices can lead to much larger than anticipated changes in sales and profitability. Sellers need to understand the heuristics consumers use, the situations in which they emerge, and recognize how they can respond in markets where information and knowledge of product attributes and competitive prices is increasingly available via the Internet. This chapter explores consumers’ behavioral reactions to price through a review of contemporary literature in the field of pricing. The chapter delineates the nature and scope of these effects based upon a critical review of the most up-to-date empirical research in the field, and concludes by providing implications for innovation in pricing, and guidance for managers to reduce the disconnect between themselves and consumers

Piezoreflectance of Dilute α-Phase Ag-In Alloys

The fractional change in reflectivity due to strain ΔRR of evaporated film samples of four silver-indium alloys was measured in the energy range 2.5-4.5 eV. The films had indium concentrations of 0.4, 1.6, 3.3, and 5.0 at.%. A Kramers-Kronig inversion of ΔRR yielded the change, due to strain, of the phase shift of the reflected electric field. The strain-induced changes of the real and imaginary parts of the complex dielectric constant, Δε1 and Δε2, were calculated. Interpretation of the structure in Δε2 of silver and the four alloys yielded the following conclusions. (a) The structure in Δε2 at 4.06 eV in silver is due to the L2′→L1 (Fermi surface to conduction band) transition and not to the L3→L2′ (d band to Fermi surface) transition as previously suggested. (b) The L2′→L1 band gap in silver is 4.15 eV and decreases to about 3.7-3.8 eV in the 5.0% indium alloy. (c) Indirect transitions contribute to ε2 and Δε2 below the direct L2′→L1 transition energy in the silver-indium alloys

Infrared Reflectivities of Magnesium Silicide, Germanide, and Stannide

The room-temperature reflection spectra of Mg2Si, Mg2Ge, and Mg2Sn have been measured at wave-lengths between 20 and 50μ. Reststrahl reflectivity peaks were observed at 36 and 45 μ for Mg2Si and Mg2Ge, respectively, and a rising reflectivity in Mg2Sn is estimated to peak at about 54 μ. The occurrence of peaks indicates that these compounds are partly ionic. The reflection spectra are more like those of the alkali halides than those of the III-V semiconducting compounds. If a simple damped harmonic oscillator is used to describe the reststrahl mode, the three Mg compounds have the same force constant for this mode. Values of dielectric constants and effective charges are estimated for Mg2Si, and are used to evaluate a previous analysis of electron mobility in this compound. Effects of free carriers on the reflectivity of Mg2Ge indicate that the effective masses are in rough agreement with the results of transport measurements