Photonics design tool for advanced CMOS nodes

Recently, the authors have demonstrated large-scale integrated systems with several million transistors and hundreds of photonic elements. Yielding such large-scale integrated systems requires a design-for-manufacture rigour that is embodied in the 10 000 to 50 000 design rules that these designs must comply within advanced complementary metal-oxide semiconductor manufacturing. Here, the authors present a photonic design automation tool which allows automatic generation of layouts without design-rule violations. This tool is written in SKILL, the native language of the mainstream electric design automation software, Cadence. This allows seamless integration of photonic and electronic design in a single environment. The tool leverages intuitive photonic layer definitions, allowing the designer to focus on the physical properties rather than on technology-dependent details. For the first time the authors present an algorithm for removal of design-rule violations from photonic layouts based on Manhattan discretisation, Boolean and sizing operations. This algorithm is not limited to the implementation in SKILL, and can in principle be implemented in any scripting language. Connectivity is achieved with software-defined waveguide ports and low-level procedures that enable auto-routing of waveguide connections.Comment: 5 pages, 10 figure

The Far-Infrared Luminosity Function from GOODS-N: Constraining the Evolution of Infrared Galaxies for z \leq 1

We present the IR luminosity function derived from ultra-deep 70 micron imaging of the GOODS-North field. The 70 micron observations are longward of the PAH and silicate features which complicate work in the MIR. We derive far-infrared luminosities for the 143 sources with S_{70} > 2 mJy (S/N > 3 \sigma). The majority (81%) of the sources have spectroscopic redshifts, and photometric redshifts are calculated for the remainder. The IR luminosity function at four redshifts (z ~ 0.28, 0.48, 0.78, and 0.97) is derived and compared to the local one. There is considerable degeneracy between luminosity and density evolution. If the evolving luminosity function is described as \rho(L, z) = (1 + z)^q \rho(L/(1 + z)^p, 0), we find q = -2.19p + 6.09. In the case of pure luminosity evolution, we find a best fit of p = 2.78^{+0.34}_{-0.32}. This is consistent with the results from 24 micron and 1.4 GHz studies. Our results confirm the emerging picture of strong evolution in LIRGs and ULIRGs at 0.4 < z < 1.1, but we find no evidence of significant evolution in the sub-LIRG (L < 10^{11} L_{\odot}) population for z < 0.4.Comment: accepted by ApJL, 5 page

Hydrometallurgy

Hydrometallurgy, which involves the use of aqueous solutions for the recovery of metals from ores, concentrates, and recycled or residual material, plays an integral role in the multi-billion dollar minerals processing industry. There are numerous hydrometallurgical process technologies used for recovering metals, such as: agglomeration; leaching; solvent extraction/ion exchange; metal recovery; and remediation of tailings/waste. Modern hydrometallurgical routes to extract metals from their ores are faced with a number of issues related to both the chemistry and engineering aspects of the processes involved. These issues include declining ore grade, variations in mineralogy across the deposits and geo-metallurgical locations of the ore site; which would influence the hydrometallurgical route chosen. The development of technologies to improve energy efficiency, water/resources consumption and waste remediation across the circuit is also an important factor to be considered. Therefore, there is an increasing need to develop novel solutions to these existing problems, to implement environmentally sustainable practices in the recovery of these valuable metals. Papers on recent advances, and review articles, particularly in regard to fundamental chemistry and the development of novel techniques and technologies in commercial processing of mineral commodities from their ores, are included in this Special Monograph on "Hydrometallurgy"

Incentive Value of Stock Options at Information Technology Companies in the Down Markets

Stock options have been criticized as fair weather friends: good at motivating and retaining executives when the market is going up, but of little incentive value when the market is going down. The veracity of this criticism is of particular importance to executives at information technology (IT) companies, where options are used aggressively and where stock declines in 2000 were extreme. In this study, we compare the performance-effectiveness of IT CEOsí stock and option holdings in the up market of 1993 through 1999 with their performance-effectiveness in the down market of 2000. We find that stock options that were exercisable had stronger positive performance effects during 2000 than in previous years but that options that were unexercisable (not vested) had much weaker performance effects in 2000 than in previous years. For non-IT CEOs, we also observe stronger performance effects for exercisable options in 2000 but we do not observe the same weakening of performance effects for unexercisable options in 2000

z ~ 4 Hα Emitters in the Great Observatories Origins Deep Survey: Tracing the Dominant Mode for Growth of Galaxies

We present evidence for strong Hα emission in galaxies with spectroscopic redshifts in the range of 3.8 10^(11) M_☉) galaxies at z ~ 3. This "strong Hα phase" of star formation plays a dominant role in galaxy growth at z ~ 4, and they are likely progenitors of massive red galaxies at lower redshifts