Tunnel junctions for InP-on-Si solar cells

Growing, by metalorganic chemical vapor deposition, a tunnel junction is described, which makes possible and ohmic back contact in an n-on-p InP solar cell on a silicon substrate. The junction between heavily doped layers of p-type InGaAs and n-type InP shows resistance low enough not to affect the performance of these cells. InP solar cells made on n-type Si substrates with this structure were measured with an efficiency of 9.9 percent. Controls using p-type GaAs substrates showed no significant difference in cell performance, indicating that the resistance associated with the tunnel junction is less than about 0.1 ohm/sq cm

A Reexamination of Professional and Popular Thought on Assistance for Economic Development: 1949-1952

Community/Rural/Urban Development,

Searching for Stoponium along with the Higgs boson

Stoponium, a bound state of top squark and its antiparticle in a supersymmetric model, may be found in the ongoing Higgs searches at the LHC. Its WW and ZZ detection ratios relative to the Standard Model Higgs boson can be more than unity from WW* threshold to the two Higgs threshold. The gamma gamma channel is equally promising. Some regions of the stoponium mass below 150 GeV are already being probed by the ATLAS and CMS experiments.Comment: 10 pages 5 figure

The Preparation Of Yeast Nucleic Acid And Its Effect On The Growth Of Rats

During the four years, 1937-41 research on the characterization of Nucleic Acid entered upon its eighth decade, yet the first problem to be posed, that concerning the nature of nucleic acid, still awaits a satisfactory solution, With the exception of a few publications that escaped general notice, it has been believed universally that one type of nucleic acid, plant nucleic acid, was always to be found in the nuclei of plant cells, and that another type of nucleic acid, animal nucleic acid, was always contained in the nuclei of animal cells. Sufficient evidence has now appeared to show that this generalization is no longer te able, feulgen, Behrens and Mahdihassan, as well as Behrens\u27, by the use of a flotation method whereby the nuclei of cells could be freed from cytoplasmic constituents, have been able to isolate animal nucleic acid from the nuclei, and lant nucleic acid from the cytoplasm of rye embryos

Conserved developmental processes and the formation of evolutionary novelties: examples from butterfly wings

The origin and diversification of evolutionary novelties—lineage-specific traits of new adaptive value—is one of the key issues in evolutionary developmental biology. However, comparative analysis of the genetic and developmental bases of such traits can be difficult when they have no obvious homologue in model organisms. The finding that the evolution of morphological novelties often involves the recruitment of pre-existing genes and/or gene networks offers the potential to overcome this challenge. Knowledge about shared developmental processes obtained from extensive studies in model organisms can then be used to understand the origin and diversification of lineage-specific structures. Here, we illustrate this approach in relation to eyespots on the wings of Bicyclus anynana butterflies. A number of spontaneous mutations isolated in the laboratory affect eyespots, lepidopteran-specific features, and also processes that are shared by most insects. We discuss how eyespot mutants with disturbed embryonic development may help elucidate the genetic pathways involved in eyespot formation, and how venation mutants with altered eyespot patterns might shed light on mechanisms of eyespot development