Photon induced secondary electron emission

Numerical models for predicting photon-induced secondary electron emission are presented. The results are compared with experimental measurements made using a Co-60 gamma ray source

Pre-hospital management of acute Addison’s Disease – Audit of patients attending a referral hospital in a regional area

Context: Adrenal crises (AC) cause morbidity and mortality in patients with Addison’s disease [primary adrenal insufficiency (PAI)]. Patient-initiated oral stress dosing, with parenteral hydrocortisone, is recommended to avert ACs. While these should be effective, the continued incidence of ACs remains largely unexplained. Methods: Audit of all attendances between 2000 and 2017 by adult patients with treated PAI to one large regional referral centre in New South Wales, Australia. Measurements were those taken on arrival at hospital. Results: There were 252 attendances by 56 patients with treated PAI during the study period. Women comprised 60.7% (n=34) of the patients. The mean age of attendees was 53.7 (19.6) years. Nearly half (45.2%, n=114) the patients had an infection. There were 61 (24.2%) ACs diagnosed by the treating clinician. Only 17.9% (n=45) of the hospital presentations followed any form of stress dosing. IM hydrocortisone was used before 7 (2.8%) attendances only. Among patients with a clinician diagnosed AC, only 32.8% (n=20) had used stress dosing before presentation. Vomiting was reported by 47.6% (n=120) of the patients but only 33 (27.5%) of these attempted stress dosing and 5 patients with vomiting used IM hydrocortisone. The number of prior presentations was a significant independent predictor of use of stress doses [1.05 (1.01,1.09)]. Conclusion: Dose escalation strategies are not used universally or correctly by unwell patients with PAI, many patients do not use IM or SC hydrocortisone injections. Previous hospital treatment increases the likelihood of stress dosing and offers the opportunity for reinforcement of prevention strategies

PILOT: design and capabilities

The proposed design for PILOT is a general-purpose, wide-field 1 degree 2.4m, f/10 Ritchey-Chretien telescope, with fast tip-tilt guiding, for use 0.5-25 microns. The design allows both wide-field and diffraction-limited use at these wavelengths. The expected overall image quality, including median seeing, is 0.28-0.3" FWHM from 0.8-2.4 microns. Point source sensitivities are estimated.Comment: 4 pages, Proceedings of 2nd ARENA conference 'The Astrophysical Science Cases at Dome C', Potsdam, 17-21 September 200

Nucleation and growth of a quasicrystalline monolayer: Bi adsorption on the five-fold surface of i-Al70Pd21Mn9

Scanning tunnelling microscopy has been used to study the formation of a Bi monolayer deposited on the five-fold surface of i-Al70Pd21Mn9. Upon deposition of low sub-monolayer coverages, the nucleation of pentagonal clusters of Bi adatoms of edge length 4.9 A is observed. The clusters have a common orientation leading to a film with five-fold symmetry. By inspection of images where both the underlying surface and the Bi atoms are resolved, the pentagonal clusters are found to nucleate on pseudo-Mackay clusters truncated such that a Mn atom lies centrally in the surface plane. The density of these sites is sufficient to form a quasiperiodic framework, and subsequent adsorption of Bi atoms ultimately leads to the formation of a quasicrystalline monolayer. The initial nucleation site is different to that proposed on the basis of recent density functional theory calculations.Comment: 6 pages, 5 figure

Formation of a quasicrystalline Pb monolayer on the ten-fold surface of the decagonal Al-Ni-Co quasicrystal

Lead has been deposited on the ten-fold surface of decagonal Al72Ni11Co17 to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular islands and the coverage saturates at 1 ML. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. Annealing the film to 600 K improves the structural quality, but causes the evaporation of some material such that the film develops pores. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak.Comment: 12 pages, 5 figure

The surface science of quasicrystals

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version

Synthesis and characteristics of polyarylene ether sulfones

A method utilizing potassium carbonate/dimethyl acetamide, as base and solvent respectively, was used for the synthesis of several homopolymers and copolymers derived from various bisphenols. It is demonstrated that this method deviates from simple second order kinetics; this deviation being due to the heterogeneous nature of the reaction. Also, it is shown that a liquid induced crystallization process can improve the solvent resistance of these polymers. Finally, a Monte Carlo simulation of the triad distribution of monomers in nonequilibrium copolycondensation is discussed

C60 adsorption on an aperiodically modulated Cu surface

Copper deposited on the ve-fold surface of icosahedral Al-Pd-Mn forms domains of a structure whose surface has a one-dimensional aperiodic modulation. It is shown that C60 deposited on this aperiodic film has highly reduced mobility as compared to C60 deposited on periodic Cu surfaces. This fnding is explained in terms of the recently proposed structural model of this system

Divestitures

This article provides an introduction to divestitures and the research streams that examine these deals. Divestitures are defined as the removal of one or more of a company’s lines of business via selloff or spinoff. In this article, we describe how research on divestitures has evolved in the finance and strategy literatures, and we explain how to design and conduct empirical research studies on this topic. We also discuss the implications of divestitures for organization design, and outline some directions for future research in this domain

Pseudomorphic Growth of a Single Element Quasiperiodic Ultrathin Film on a Quasicrystal Substrate

An ultrathin film with a periodic interlayer spacing was grown by the deposition of Cu atoms on thefivefold surface of the icosahedral Al70 Pd21 Mn9 quasicrystal. For coverages from 5 to 25 monolayers, a distinctive quasiperiodic low-energy electron diffraction pattern is observed. Scanning tunneling microscopy images show that the in-plane structure comprises rows having separations of S = 4.5 �0.2 �A and L = 7.3 0.3 A, whose ratio equals � =1.618... within experimental error. The sequences of such row separations form segments of terms of the Fibonacci sequence, indicative of the formation of a pseudomorphic Cu film