Seminar on Securities Law

Materials from the UK/CLE Seminar on Securities Law held February 14-15, 1986

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

The James Webb Space Telescope (JWST) is a large, infrared space telescope that has recently started its science program which will enable breakthroughs in astrophysics and planetary science. Notably, JWST will provide the very first observations of the earliest luminous objects in the Universe and start a new era of exoplanet atmospheric characterization. This transformative science is enabled by a 6.6 m telescope that is passively cooled with a 5-layer sunshield. The primary mirror is comprised of 18 controllable, low areal density hexagonal segments, that were aligned and phased relative to each other in orbit using innovative image-based wavefront sensing and control algorithms. This revolutionary telescope took more than two decades to develop with a widely distributed team across engineering disciplines. We present an overview of the telescope requirements, architecture, development, superb on-orbit performance, and lessons learned. JWST successfully demonstrates a segmented aperture space telescope and establishes a path to building even larger space telescopes.Comment: accepted by PASP for JWST Overview Special Issue; 34 pages, 25 figure

Synthesis, Structure and Nickel Carbonyl Complexes of Dialkylterphenyl Phosphines

The experimental and computational characterization of a series of dialkylterphenyl phosphines, PR2Ar′ is described. The new P‐donors comprise five compounds of general formula PR2Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0001 (R=Me, Et, iPr, c‐C5H9 and c‐C6H11); Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0002 = 2,6‐C6H3‐(3,5‐C6H3‐(CMe3)2)2), and another five PR2Ar′ phosphines containing the bulky alkyl groups iPr, c‐C5H9 or c‐C6H11, in combination with Ar′=Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0003 , Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0004 , or Arurn:x-wiley:09476539:media:chem201803598:chem201803598-math-0005 (L1–L10). Steric and electronic parameters have been determined computationally and from IR and X‐ray data obtained for the phosphines and for some derivatives, including tricarbonyl and dicarbonyl nickel complexes, Ni(CO)3(PR2Ar′) and Ni(CO)2(PR2Ar′). In the solid state, the free phosphines PR2Ar′ adopt one of the three possible structures formally related by rotation around the Cipso−P bond. Details on their relative energies and on the influence of the free phosphine structure on its coordination chemistry towards Ni(CO)n (n = 2, 3) fragments has been obtained by experimental and computational methods.Peer reviewe