Subsurface burnout mechanisms in gallium arsenide (GAAS) electronic devices

This paper reviews the present knowledge on subsurface burnout mechanisms in Gallium Arsenide (GaAs) electronic devices. The results of the work should assist in the creation of more reliable devices with greater radiation hardness.     

On the calculation of the U-value of walls containing slotted bricks or blocks

The thermal transmittance of walls containing slotted bricks or blocks has been studied using a finite element computer program. The results are compared with conventional calculation methods, and a new manual method based on a more realistic model of heat flow in slotted blocks is proposed.     

Continuous ion exchange using magnetic shell resins. II. Dealkalisation—pilot plant study

From the results obtained in the treatment of a number of hard, alkaline feed waters in a pilot scale dealkalisation plant, it has been shown that the use of a magnetic carboxylic acid resin in a fluidised bed has definite advantages over conventional systems. Less resin is needed and simpler plants can handle the same throughput of raw water whilst maintaining the same quality of product. Plant operation is truely continuous without any complex valve system or pressurised vessels.     

Promise-of-treatment as an opening strategy for psychotherapy.

Contends that withholding of explicit, formal treatment until after S's completion of experimental and information-gathering ordeals is an opening tactic for psychotherapy that potentiates both a course and a conclusion for the therapeutic process. The benefits of the promise-of-treatment strategy include removal of "failure" from the initial process, ability to assess and intensify client motivation, and possible eliciting of the placebo effect. Clients may be asked to delay treatment until the best one is formulated. Covertly therapeutic tasks (e.g., testing conventional cures, attempting personal solutions, rehearsing symptoms, reframing, slowly developing insight, pretending to be cured, pretending to be sick, spontaneously changing, gathering information) allow the client to do something different and to make a change for the better. Case examples of a 40-yr-old female binge eater, a 20-yr-old male with a sleep disorder, and a 15-yr-old compulsive face scratcher are presented to illustrate the promise-of-treatment strategy. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The detection of sodium vapor bubble collapse in a liquid metal fast breeder reactor

Sodium boiling detection utilizing the sound pressure emanated during the collapse of a sodium vapor bubble in a subcooled media is discussed in terms of the sound characteristic, the reactor ambient noise background, transmission loss considerations and performance criteria. Data obtained in several loss of flow experiments on Fast Test Reactor Fuel Elements indicate that the collapse of the sodium vapor bubble depends on the presence of a subcooled structure or sodium. The collapse pressure pulse was observed in all cases to be on the order of a kPa, indicating a soft type of cavitational collapse. Spectral examination of the pulses indicates the response function of the test structure and geometry is important. The sodium boiling observed in these experiments was observed to occur at a low (<50°C) liquid superheat with the rate of occurrence of sodium vapor bubble collapse in the 3 to 30 Hz range. Reactor ambient noise data were found to be due to machinery induced vibrations, flow induced vibrations, and flow noise. These data were further found to be weakly stationary enhancing the possibility of acoustic surveillance of an operating Liquid Metal Fast Breeder Reactor. Based on these noise characteristics and extrapolating the noise measurements from the Fast Flux Test Facility Pump (FFTP), one would expect a signal to noise ratio of up to 20 dB in the absence of transmission loss. The requirement of a low false alarm probability is shown to necessitate post detection analysis of the collapse event sequence and the cross correlation with the second derivative of the neutronic boiling detection signal. Sodium boiling detection using the sounds emitted during sodium vapor bubble collapse are shown to be feasible but a need for in-reactor demonstration is necessary.     

Comparison of dark-field and bright-field incident illumination for in vivo measurements of reduced pyridine nucleotides

Bright-field and dark-field illumination techniques for in vivo measurements of reduced pyridine nucleotide fluorescence were compared in 15 rats during periods of normocapnia, hypocapnia, hypercapnia, and anoxia. Parameters investigated included fluorescence, cortical reflectance, cortical blood flow, and electroencephalograms. In normal brain, with preserved autoregulation, reduced pyridine nucleotide fluorescence was constant through a wide range in Pa(CO2), cortical blood flow, and cerebral blood volume in animals studied using vertical illumination (bright-field) techniques. There was a marked increase in reduced pyridine nucleotide fluorescence at death from anoxia. Artifacts were reduced by monochromators for excitation, emission, and reflected light; low-intensity vertical excitation energy and high-sensitivity recording instrumentation; and a small avascular (123 microns) field. Potential sources of error include photodecomposition, hemoglobin interference from absorption and reflectance, and light scattering. Vertical excitation techniques using a small field appeared to give more reliable and reproducible results than circumferential techniques using a larger field of observation.     

An assessment of the suitability of rf sputtered amorphous hydrogenated Si as a potential solar cell material

We review several material properties thought to be important for the production of high efficiency amorphous semi-conductor Schottky barrier solar cells, with particular reference to a systematic study made in this laboratory of amorphous Si:H alloys prepared by rf sputtering. These requirements include: (a) an optical gap which efficiently absorbs the solar spectrum in a thin film, (b) a Fermi level position close to the conduction band for a large work function difference between metal and semiconductor, (c) high photoconductivity, (d) long carrier migration lengths, and (e) a low overall density of gap states. Using our data on these electronic properties, we show that we can satisfy these conditions somewhat by depositing at an argon pressure of 20 mTorr. Furthermore, we demonstrate, using a simple Schottky barrier structure, that significant improvements in device performance are achieved, particularly in open circuit voltage, as the above properties are optimized. Other factors which might still limit the performance of the device are discussed, and from an examination of the temperature dependence of the short circuit current, we conclude that the most likely to be important is the “effective” diffusion length for valence band holes.     

Respiratory abnormalities and ventilatory capacity in a Papua New Guinea Island community

Several molecular forms of human glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49) corresponding to different stages of post-synthetic modifications have been purified from human leukocytes. The various enzyme forms were different in their specific activity, their kinetic properties and their isoelectrofusing pattern. The molecular weight of the subunits of the different forms was not modified. The changes in the electrofocusing pattern were not due to modifications of the N-terminal ends, the oxidation of thiol groups or the non-covalent fixation of an acid molecule upon the enzyme. Carboxypeptidase B cleaved a C-terminal lysine from the different enzyme forms and shifted the isoelectric point of the different enzyme active bands towards the acid pH. The different enzyme forms studied here seemed to result from the action upon 'native glucose-6-phosphate dehydrogenase' of 'modifying factors' especially abundant in some leukemic granulocytes. The modifying factors did not seem to be consumed during the 'modification' of glucose-6-phosphate dehydrogenase. Moreover, the storage for one year of unmodified enzyme resulted in changes in its electrofocusing pattern similar to those quickly induced by the 'modifying factors'. Consequently it appears that the modifying factors are catalysts of the modification of special residues of glucose-6-phosphate dehydrogenase. The hypothesis that this modification involves the deamination of asparagine or glutamine residues is put forward.