Concurrency reduction of untimed latch protocols - theory and practice

Journal ArticleA systematic investigation into concurrency reduction of untimed asynchronous 4-phase latch controllers is reported. Starting with a state graph that exhibits maximal concurrency, rules are provided for systematically reducing its states and thereby curtailing its behaviors. The rules predict liveness and occupancy, as well as the regularity and behavior of their pipelines. The rules also reveal the precise extent of the design space and thus provide a secure platform on which to study the implications of concurrency reduction on power, performance and area by implementing and evaluating the complete set of abstracted controllers. This complete characterization enhances the understanding and usage of concurrency and its reduction in handshake protocols. Trade-offs have been observed and reported which will aid designers in trying to find the best protocols for a required specification. Finally, the best synthesized protocols in this class have been identified

Enhanced self-field critical current density of nano-composite YBa(2)Cu(3)O(7) thin films grown by pulsed-laser deposition

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ EPLA, 2008.Enhanced self-field critical current density Jc of novel, high-temperature superconducting thin films is reported. Layers are deposited on (001) MgO substrates by laser ablation of YBa2Cu3O7−δ(Y-123) ceramics containing Y2Ba4CuMOx (M-2411, M=Ag, Nb, Ru, Zr) nano-particles. The Jc of films depends on the secondary-phase content of the ceramic targets, which was varied between 0 and 15 mol%. Composite layers (2 mol% of Ag-2411 and Nb-2411) exhibit Jc values at 77 K of up to 5.1 MA/cm2, which is 3 to 4 times higher than those observed in films deposited from phase pure Y-123 ceramics. Nb-2411 grows epitaxially in the composite layers and the estimated crystallite size is ~10 nm.The Austrian Science Fund, the Austrian Federal Ministry of Economics and Labour, the European Science Foundation and the Higher Education Commission of Pakistan

Magnetization creep and decay in YBa2Cu3O7−x thin films with artificial nanostructure pinning

Critical current and flux pinning have been studied for YBa_2Cu_3O_7−x thin films with Y_2BaCuO_5 (211) precipitates introduced as layers and as random distributions. The 211 precipitates were introduced during pulsed laser deposition. In the case of the layered sample, the strata were spaced approximately 6.5 nm apart throughout the film thickness. Magnetically determined critical current density (J_c) was then fitted to J_c∝B^−α above a magnetic field B*, below which a relatively field independent J_c-self-field was observed, consistent with previous results. Values of α were suppressed from the control sample values of α=0.5 to lower values for pinned samples, reaching α=0.2 for the layer pinned 211 sample at low temperatures. M-H was then measured as a function of ramp rate, and U(J) vs J curves were extracted for temperatures from 4.2 to 77 K for pinned and control samples. Direct magnetization decay measurements were made for the 211 layer pinned sample, and good agreement was seen with ramp-rate-derived results. Using U(J)=(U_0∕μ)[(J_c∕J)^μ−1]B^−ν, values of μ≅0.6–0.8 were seen for all samples, while ν≅0.4 for control samples, 0.1 for layer pinned samples, and 0.2–0.4 for the random pinned samples. The activation energy scale U_0 was 600–700 and 400 K for layer pinned and control samples, respectively, and 400–500 K for the random pinned samples. The values of μ and ν extracted were inconsistent with two dimensional pinning behavior in all cases, even though the layer spacing in the layer pinned sample is smaller than the calculated collective correlation length. While the layer pinned sample is clearly in the collective pinning regime, the artificial defects in the random pinned sample may be in the isolated strong pinning regime

A Comparative Study of Three Different Chemical Vapor Deposition Techniques of Carbon Nanotube Growth on Diamond Films

This paper compares between the methods of growing carbon nanotubes (CNTs) on diamond substrates and evaluates the quality of the CNTs and the interfacial strength. One potential application for these materials is a heat sink/spreader for high-power electronic devices. The CNTs and diamond substrates have a significantly higher specific thermal conductivity than traditional heat sink/spreader materials making them good replacement candidates. Only limited research has been performed on these CNT/diamond structures and their suitability of different growth methods. This study investigates three potential chemical vapor deposition (CVD) techniques for growing CNTs on diamond: thermal CVD (T-CVD), microwave plasma-enhanced CVD (MPE-CVD), and floating catalyst thermal CVD (FCT-CVD). Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM) were used to analyze the morphology and topology of the CNTs. Raman spectroscopy was used to assess the quality of the CNTs by determining the ID/IG peak intensity ratios. Additionally, the CNT/diamond samples were sonicated for qualitative comparisons of the durability of the CNT forests. T-CVD provided the largest diameter tubes, with catalysts residing mainly at the CNT/diamond interface. The MPE-CVD process yielded non uniform defective CNTs, and FCT-CVD resulted in the smallest diameter CNTs with catalyst particles imbedded throughout the length of the nanotubes

Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres

We present a comprehensive description of the theory and practice of opacity calculations from the infrared to the ultraviolet needed to generate models of the atmospheres of brown dwarfs and extrasolar giant planets. Methods for using existing line lists and spectroscopic databases in disparate formats are presented and plots of the resulting absorptive opacities versus wavelength for the most important molecules and atoms at representative temperature/pressure points are provided. Electronic, ro-vibrational, bound-free, bound-bound, free-free, and collision-induced transitions and monochromatic opacities are derived, discussed, and analyzed. The species addressed include the alkali metals, iron, heavy metal oxides, metal hydrides, $H_2$, $H_2O$, $CH_4$, $CO$, $NH_3$, $H_2S$, $PH_3$, and representative grains. [Abridged]Comment: 28 pages of text, plus 22 figures, accepted to the Astrophysical Journal Supplement Series, replaced with more compact emulateapj versio

On the Job

<p>DPSCs were exposed to various MG132 or p65 siRNA concentrations (A and B, respectively) and cytokines in the presence of MG132 or p65 siRNA (C and D, respectively) for 7 days. Col(I)-α1 mRNA was assayed using qRT-PCR. Data are presented as the mean ± S. E. M. of triplicate measures from triplicate experiments. Symbols: Asterisks (*) indicate statistical comparison with control result; plus signs (+) indicate statistical comparison with IL-1β (0.5 ng/ml) and TNFα (1.0 ng/ml) treatment (low cytokine dose); triangle (Δ) indicates statistical comparison with IL-1β (10.0 ng/ml) and TNFα (20.0 ng/ml) treatment (high cytokine dose). Statistical comparison was made using ANOVA testing with Dunnett’s posthoc analysis. Statistical significance was represented by *, +, or Δ for <i>p</i> < 0.05; **, ++, or ΔΔ for p < 0.01; ***, +++, or ΔΔΔ for p < 0.001.</p

Mineralogy of the Lunar Crust in Spatial Context: First Results from the Moon Mineralogy Mapper (M3)

India's Chandrayaan-1 successfully launched October 22, 2008 and went into lunar orbit a few weeks later. Commissioning of instruments began in late November and was near complete by the end of the year. Initial data for NASA's Moon Mineralogy Mapper (M3) were acquired across the Orientale Basin and the science results are discussed here. M 3 image-cube data provide mineralogy of the surface in geologic context. A major new result is that the existence and distribution of massive amounts of anorthosite as a continuous stratigraphic crustal layer is now irrefutable

Character and spatial distribution of OH/H<SUB>2</SUB>O on the surface of the moon seen by M<SUP>3</SUP> on Chandrayaan-1

The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration