Technique for pinpointing submicron particles in the electron microprobe

Series of electron micrographs at successively lower magnifications can localize the substrate area sufficiently for a particle to be picked up by the beam of the electron microprobe. This approach could be modified to apply to fractographic studies, particularly of oxidation products stripped from fractures

Pionic Color Transparency

We use a semi-classical approximation to investigate the effects of color transparency on pion electroproduction reactions. The resulting reduced nuclear interactions produce significant, but not dominating, differences with the results of conventional distorted-wave, Glauber-type treatments at kinematics accessible to Jefferson Laboratory. Nuclear effects that could mimic the influence of color transparency are also discussed.Comment: 10 pages, 6 figure

New hyperthermal thermosetting heterocyclic polymers

Polyimidazopyrrolone polymers, formed by the condensation of aromatic dianhydrides with aromatic tetraamines in various solvents, form moldings that resist degradation in air and retain great strength at 400 to 700 degrees F. The resins have good insulating properties, are easy to mold, and make good protective coatings

Microprobe investigation of brittle segregates in aluminum MIG and TIG welds

Quantitative microprobe analysis of segregated particles in aluminum MIG /Metal Inert Gas/ and TIG /Tungsten Inert Gas/ welds indicated that there were about ten different kinds of particles, corresponding to ten different intermetallic compounds. Differences between MIG and TIG welds related to the individual cooling rates of these welds

Fourlined Plant Bug (Hemiptera: Miridae), a Reappraisal: Life History, Host Plants, and Plant Response to Feeding

Phenology of the fourlined plant bug, Poecilocapsus lineatus, is presented for southcen- tral Pennsylvania; life history and habits are re-examined. Although breeding was previously thought to occur only on woody plants, we found that nymphs develop on numerous herbs. An extensive list of hosts, more than 250 species in 57 families, is compiled from the literature and the authors\u27 observations; preferences are noted for plants in the Labiatae, Solanaceae, and Compositae. Damage consists of lesions on foliage, the size and shape of the spots varying with leaf texture, pubescence, and venation. Plant response to feeding is immediately visible, the lesions seeming to appear simultaneously with insertion of the bug\u27s stylets. Histolysis of plant tissues, the most rapid response to mind feeding yet reported, is attributed to a potent lipid enzyme whose active constituents are under investigation

An analytic model for the epoch of halo creation

In this paper we describe the Bayesian link between the cosmological mass function and the distribution of times at which isolated halos of a given mass exist. By assuming that clumps of dark matter undergo monotonic growth on the time-scales of interest, this distribution of times is also the distribution of `creation' times of the halos. This monotonic growth is an inevitable aspect of gravitational instability. The spherical top-hat collapse model is used to estimate the rate at which clumps of dark matter collapse. This gives the prior for the creation time given no information about halo mass. Applying Bayes' theorem then allows any mass function to be converted into a distribution of times at which halos of a given mass are created. This general result covers both Gaussian and non-Gaussian models. We also demonstrate how the mass function and the creation time distribution can be combined to give a joint density function, and discuss the relation between the time distribution of major merger events and the formula calculated. Finally, we determine the creation time of halos within three N-body simulations, and compare the link between the mass function and creation rate with the analytic theory.Comment: 7 pages, 2 figures, submitted to MNRA

An imaging K-band survey - I: The catalogue, star and galaxy counts

We present results from a large area (552\,\sqamin) imaging $K$-band survey to a 5$\sigma$ limit of $K\simeq 17.3$. We have optical-infrared colours of almost all the objects in the sample. Star-galaxy discrimination is performed and the results used to derive the infrared star and galaxy counts. $K$-band ``no-evolution'' galaxy-count models are constructed and compared with the observed data. In the infrared, there is no counterpart for the large excess of faint galaxies over the no-evolution model seen in optical counts. However, we show that the $K$ counts can be remarkably insensitive to evolution under certain reasonable assumptions. Finally, model predictions for $K$-selected redshift surveys are derived.Comment: MNRAS in press. 21 pages plain TeX; figs plus table 4 available via anonymous ftp from /pub/kgb/paper1/sissa.uu at ftp.ast.cam.ac.u

Parametric study of advanced multistage axial-flow compressors

Axial flow compressor study to increase pressure ratio and reduce overall lengt

Charge Density of the Neutron

A model-independent analysis of the infinite-momentum-frame charge density of partons in the transverse plane is presented for the nucleon. We find that the neutron parton charge density is negative at the center, so that the square of the transverse charge radius is positive, in contrast with many expectations. Additionally, the proton's central u quark charge density is larger than that of the d quark by about 70 %. The proton (neutron) charge density has a long range positively (negatively) charged component.Comment: 7 pages, three figures The replacement mainly concerns correcting an error made in computing the proton up and down quark densities from the correctly computed proton and neutron charge densities. The proton central u quark density is now larger than that of the d quar