Void-swelling in irons and ferritic steels: II. An experimental survey of materials irradiated in a fast reactor

The void-swelling response of a wide range of ferritic alloys irradiated in the Dounreay Fast Reactor to displacement doses up to 30 dpa (N/2) and covering the temperature range 380–615°C have been compared. The materials selected included high purity irons, together with commercial mild and low alloy steels, high chromium (12–14%) ferritic and martensitic stainless steels and a range of high purity binary iron-chromium alloys containing chromium contents up to 15%. The pure irons and binary iron-chromium alloys exhibited measurable but relatively low swellings (<1%) whilst all the commercial ferritic steels appeared to be void-swelling resistant, with swellings below the experimental detection limit (0.1%). The pattern emerging is thus one of overall swelling resistance in ferritic materials as a general class. Void-swelling in the pure iron peaked at two irradiation temperatures (~420, ~510°C), and the low magnitude of the swelling was rationalized in terms of the operation of solute-controlled swelling suppression mechanisms involving residual interstitial impurities. The complex functional dependence of peak-swelling on chromium content in the binary iron-chromium alloys was explained in terms of void-swelling suppression based on the presence of weak interactions between chromium atoms in solution and vacancies, modified by depletion of chromium from solid solution by α' precipitation at chromium contents exceeding 10%. The validation of the high swelling resistance of the 12% Cr martensitic stainless steels in a fast reactor environment provides confidence in the selection of these alloys as alternative core component materials for commercial fast reactor systems.     

The effectiveness of the exciton mechanism in superconducting layered compounds

The excitonic interaction resulting from an array of adsorbed dyes on a plane conducting metallic sheet is considered. We show that only with the appropriate choice of dye and with certain constraints on the structure and properties of the metallic system can this interaction be strong enough to influence the superconducting properties of the sheet.     

The use of functionalized polymers as photosensitizers in an energy storage reaction

Insoluble polymer bound photosensitizers, useful for the conversion of norbornadiene (1) to quadricyclene (2), have been synthesized. An acetophenone analogue was produced by Friedel-Crafts acylation of polystyrene resin while treatment of chloromethylated resin with salicyladehyde and triethylamine produced an anlogue of benzyloxybenzaldehyde. Reaction of lithio---polystyrene resin with methyl 4-(N,N-dimethylamino)benzoate gave a ketone equivalent to 4-(N,N-dimethylamino)benzophenone (3). Quantum yields for the conversion of 1 and 2 using the polymer bound sensitizers were generally comparable to, but slightly lower than, the analogous compound in homogeneous solution. The quantum yield of polymer bound 3 was less solvent dependent than that of the homogeneous counterpart. The advantages of isolating the photosensitizer to the photochemical reactor stage of a photochemical solar energy storage device are discussed. Efficient sensitization by polymer bound photosensitizers demonstrates the feasibility of this approach.     

Josephson junctions as self-oscillating mixers at 34 GHz

Adjustable point-contact Josephson junctions have been used as self-oscillating mixers at 34 GHz, with an intermediate frequency of 300 MHz. The average conversion loss was about 18 dB, but mismatch losses and waveguide losses may amount to 10 dB at present.     

The primacy of affective judgment from a teleological perspective.

States that in overlooking the studies on affective judgment of J. F. Rychlak (1977), R. B. Zajonc (see record 1980-09733-001) has omitted an entire theoretical approach that should be seriously considered in discussions of the primacy of affect. This omission is corrected with a brief review of Rychlak's teleological theory and its contrast with Zajonc's approach. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Localization of intraorbital foreign bodies

A study was performed utilizing 3 mock eyes of different sizes to determine the precision and accuracy of 3 radiographic methods of localization of intraorbital foreign bodies. The Comberg method was found to be the most precise and accurate, next, the Sweet method, and then the modified spectacle frame method. However, the modified spectacle frame field expedient method of localization yielded a surprisingly high degree of accuracy in 2 of the 3 planes of reference, that is, mediolaterally and superointeriorly. A more accurate field expedient type of device which will permit greater accuracy in localization of intraorbital foreign bodies in the anteroposterior axis is currently under development.     

Spatial coherence of backscatter for the nonlinearly produced second harmonic for specific transmit apodizations

To be successful, correlation-based, phase-aberration correction requires a high correlation among backscattered signals. For harmonic imaging, the spatial coherence of backscatter for the second harmonic component is different than the spatial coherence of backscatter for the fundamental component. The purpose of this work was to determine the effect of changing the transmit apodization on the spatial coherence of backscatter for the nonlinearly generated second harmonic. Our approach was to determine the effective apodizations for the fundamental and second harmonic using both experimental measurements and simulations. Two-dimensional measurements of the transverse cross sections of the finite-amplitude ultrasonic fields generated by rectangular and circular apertures were acquired with a hydrophone. Three different one-dimensional transmit apodization functions were investigated: uniform, Riesz, and trapezoidal. An effective apodization was obtained for each transmit apodization by backpropagating the values measured from within the transmit focal zone using a linear angular spectrum approach. Predictions of the spatial coherence of backscatter were obtained using the pulse-echo Van Cittert-Zernike theorem. In all cases the effective apodization at 2f was narrower than the transmit apodization. We demonstrate that certain transmit apodizations result in a greater spatial coherence of backscatter at the second harmonic than at the fundamental.     

Direct from polyacrylamide gel infrared laser desorption/ionization

The direct combination of gel electrophoresis and infrared laser desorption/ionization time-of-flight mass spectrometry has been demonstrated. We present results for infrared laser desorption and ionization mass spectrometry of peptides and proteins directly from a polyacrylamide gel without the addition of a matrix. Analyte molecules up to 6 kDa were ionized directly from a vacuum-dried sodium dodecyl sulfate-polyacrylamide gel after electrophoretic separation. Mass spectra were obtained at the wavelength of 2.94 microm, which is consistent with IR absorption by N-H and O-H stretch vibrations of water and other constituents of the gel. A 5-nmol quantity of peptide or protein was loaded per gel slot, although it was possible to obtain mass spectra from a small fraction of the gel spot. This technique shows promise for the direct identification of both parent and fragment masses of proteins contained in polyacrylamide gels.