Ultrahigh-speed heterojunction bipolar transistormultiplexer/demultiplexer ICs

High-speed 2-b monolithic integrated multiplexer (MUX) and demultiplexer (DMUX) circuits have been developed using self-aligned AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with improved high-speed performance. Both ICs were designed using emitter-coupled logic. The 2:1 MUX was composed of a D-type flip-flop (D-FF) merging a selector gate and a T-type flip-flop (T-FF). The 1:2 DMUX consisted of two D-FFs driven at a clock of half the rate of the input data. Error-free operation with a pseudorandom pattern was confirmed up to 10 Gb/s. The rise and fall times of the output signals of both ICs were 40 and 25 ps, respectively. HBT frequency dividers were used as inputs for both ICs in order to find the maximum operation speed. Although only a few test patterns were available, the maximum operation speeds of the MUX and DMUX were found to be around 15 and 19 Gb/s, respectively     

Approaching (100)<0vw> by Rolling Directionally Solidified Silicon Steels

Based on the possible ability of strip casting to produce a (100)<0vw> fibre texture by directional solidification, experiments of rolling, annealing and magnetic measurement were performed on samples that were directionally solidified by other means. Samples with a final texture of strong (001) component were obtained in steels with 3 wt.% Si and 0.2 wt.% Al. A B₅₀ value of 1.71T was obtained in a as‐cast ring specimen. Starting samples have columnar grains with a diameter of about 1mm diameter tilted about 9°, on the average, relative to a perfect <100>//ND. Cold rolling produced the expected rotated cube (001)<>. Further processing steps led to the final texture mentioned above. The paper presents the texture evolution along the processing steps.     

TEM study of the influence of antisite defects on magnetic domain structures in double perovskite Ba2FeMoO6

Magnetic domain structures and crystal structures of double perovskite Ba(2)FeMoO(6) were studied using Lorentz transmission electron microscopy (TEM), dark-field imaging and high-resolution TEM. Two types of magnetic domain structure were observed below the Curie temperature: an ordinary 180 degrees ferromagnetic domain structure and a typical maze-pattern structure. In regions where maze-pattern structures were observed, antiphase boundaries were found by dark-field imaging and high-resolution TEM and develop densely in Fe/Mo-ordering domains, suggesting that Fe/Mo antisite defects affect magnetic domain structures.     

Transit-time reduction in AlGaAs/GaAs HBTs utilizing velocityovershoot in the p-type collector region

The effect of electron-velocity overshoot in a p-type GaAs collector on the transit-time reduction of AlGaAs/GaAs HBTs (heterojunction bipolar transistors) is investigated. A cutoff frequency improvement of about 30% over the conventional n-type GaAs collector was obtained in p-type collector HBTs for the same collector depletion-layer width. A significant increase in electron velocity in the p-type GaAs collector layer was confirmed by a simple analysis     

Beneficial effect of MET-88, a gamma-butyrobetaine hydroxylase inhibitor, on energy metabolism in ischemic dog hearts

Recent analyses of the professions have considered the question of the changing nature of professional power. This study is an interpretive analysis of the meaning of physicians' discourse in the face of a perceived challenge to the traditional boundaries of clinical practice from malpractice suits. The data for this analysis were drawn from interviews with physicians from three specialties and from documents produced by the AMA/Specialty Society. Four modes of discourse were observed: (1) affective lament; (2) rejection of tort law; (3) complaints about a deterioration in the culture of clinical practice; and (4) a call for active campaigning. Analysis of the modes of discourse highlights both the ways in which professional power is subjected to challenge and the forms of political, financial, and cultural struggle that professional organizations and individuals engage in to resist such challenges.     

Pressurized water reactor core instrument tube ruptures: experimental simulation at the ROSA-IV lstf

A small-break loss-of-coolant accident (SBLOCA) initiated by the rupture of pressurized water reactor (PWR) core instrument tubes was simulated using the ROSA-IV Large Scale Test Facility (LSTF). The experimental results were characterized by a single-phase liquid discharge continuing for a long period until the pressure vessel coolant inventory was significantly depleted. This experiment was analyzed using three advanced LOCA analysis codes, RELAP5/MOD2, TRACPF1/MOD1 and CATHARE-1, to assess the predictive abilities of these codes. Although all these codes simulated the experimental results qualitatively, discrepancies were found between the predictions and data regarding the break flowrate, spatial distribution of coolant in the primary system and core rod temperature responses.     

Light element analysis in oxycarbonate superconductors using EELS

Elemental analysis in an oxycarbonate superconductor ((Cu,N,C)Sr2CaCu2Oy) is conducted using transmission electron microscope-electron energy-loss spectroscopy with detector-gain correction. The gain correction enables highly sensitive elemental analysis and precise measurement of energy-loss near edge structures (ELNESs). It is found that carbon is included as a CO3 group, because the carbon K-edge in the oxycarbonate shows the same ELNES observed from CaCO3. Nitrogen ELNES is similar to that of Sr(NO3)2, so nitrogen is contained as a NO3 group. Although both CO3(2-) and NO3- have similar planar atomic arrangements, the nitrogen ELNES observed is different from that of carbon. EEL spectrum simulation based on DV-Xalpha method is used to interpret the difference.     

Monitoring Photosynthetic Activity in Microalgal Cells by Raman Spectroscopy with Deuterium Oxide as a Tracking Probe

Microalgae offer great potential for the production of biofuel, but high photosynthetic activity is demanded for the practical realisation of microalgal biofuels. To this end, it is essential to evaluate the photosynthetic activity of single microalgal cells in a heterogeneous population. In this study, we present a method to monitor the photosynthetic activity of microalgae (in particular Euglena gracilis, a microalgal species of unicellular, photosynthetic, flagellate protists as our model organism) at single-cell resolution by Raman spectroscopy with deuterium from deuterium oxide (D₂O) as a tracking probe. Specifically, we replaced H₂O in culture media with D₂O up to a concentration of 20 % without disturbing the growth rate of E. gracilis cells and evaluated C−D bond formation as a consequence of photosynthetic reactions by Raman spectroscopy. We used the probe to monitor the kinetics of the C−D bond formation in E. gracilis cells by incubating them in D₂O media under light irradiation. Furthermore, we demonstrated Raman microscopy imaging of each single E. gracilis cell to discriminate deuterated cells from normal cells. Our results hold great promise for Raman-based screening of E. gracilis and potentially other microalgae with high photosynthetic activity by using D₂O as a tracking probe.     

Temperature-induced changes of the electrical and mechanical properties of aerosol-deposited BaTiO3 thick films for energy storage applications

Aerosol deposition (AD) is a room-temperature film deposition method for the fabrication of scalable ferroelectric ceramic films on different substrates, which is particularly appealing for thick film energy storage applications. However, the electrical and mechanical properties of AD ferroelectric films are not yet satisfactorily understood. Here, we report the dielectric, energy storage, and mechanical properties of aerosol-deposited BaTiO₃ (AD-BT) thick films with nanosized grains by combining macroscopic electric measurements with indentation tests. We find that thermal annealing is an effective way to improve dielectric permittivity and polarization of the AD-BT film, as well as to increase the hardness and Young's modulus of the film. However, crack formation in the annealed AD-BT film is promoted in comparison to the as-processed sample, suggesting that the interplay between the nanosized grains and release of the internal stress during annealing may have major consequences for the mechanical properties and hence should be taken into consideration in application.