DOCSLIB.ORG

Ferdinand Braun

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ferdinand Braun FERDINAND Braun. A PIONEER IN WIRELESS technology AND electronics Ferdinand Braun – A pioneer in wireless technologY and electronics Peter Russer n 1909 Ferdinand Braun and Guglielmo Marconi jointly received the Nobel Prize for their groundbreaking contributions to wireless telegraphy. Beyond numerous important contributions to wireless transmitter and receiver cir- cuit technology Ferdinand Braun has given other epoch-making contribu- tions to electronics and wireless technology, including the discovery of the rectifying properties of a metal-semiconductor junction in 1874, the invention of the Icathode ray tube (Braunsche Röhre) in 1897, and precise voltage measurement in- struments. He has given the impact to the foundation of “Hartmann & Braun” and “Telefunken” and had a considerable influence on the industrial development of Ger- man wireless technology. Introduction Ferdinand Braun (1850-1918) has been an extraordinary influential pioneer in wire- less technology who has had a strong impact on the industrial development of that field. He has given three seminal contributions to radio science and electronics: – The discovery of unipolar conduction of metalsemiconductor junctions in 1874 is the starting point from which solid state electronics develops.1 – The invention of the cathode ray tube (Braun’s tube) in 1897 provided for a cen- tury the primary electronic display device for measurement equipment, radar, television and computers.2 – The introduction of coupled resonant circuits in wireless transmitters in 1898 al- lowed to bridge higher distances in wireless telegraphy and has been the precon- dition for Guglielmo Marconi’s success in the first transatlantic wireless trans- mission in 1901.3 © 2009 EUROPEAN MICROWAVE ASSOCIATION (EUMA). REPRINTED WITH PERMISSION, FROM P. RUSSER, “FERDINAND BRAUN – A PIONeeR IN WIRELESS TECHNOLOGY AND ELECTRONICS”, Proceedings of the 39th European Microwave Conference, ROme, ITALY, OCTObeR 2009, PP. 547-554. 1 F. Braun, “Ueber die Stromleitung durch Schwefelmetalle”, Annalen der Physik und Chemie, 229(1875), 12, pp. 556-563, . 2 F. Braun, “Ueber ein Verfahren zur Demonstration und zum Studium des zeitlichen Verlaufes variabler Ströme”, Annalen der Physik und Chemie, 296(1897), 3, pp. 552-559. 3 F. Braun, Drahtlose Telegraphie durch Wasser und Luft (Leipzig, 1901), K.F. Braun, “Electrical oscillations and wireless telegraphy”, in: From Nobel Lectures, Physics 1901-1921 (Amsterdam, 1967), pp. 226-245. 228 FERDINAND Braun. A PIONEER IN WIRELESS technology AND electronics For the third contribution Ferdinand Braun together with Gug- lielmo Marconi received the Nobel Prize in 1909. Giving the initial impulse for the foundation of companies like Hartmann & Braun and Telefunken, Ferdinand Braun has influenced strongly the industrial development of wireless technology in Germany at the beginning of the 20th century. It has been the achievement of Friedrich Kurylo, hav- ing written the first biography of Ferdinand Braun.4 As a reference the later biography of Florian Hars is more reliable.5 Interesting material also can be found in6 and in Georg Schmucker’s biography of Jona- than Zenneck.7 Early life and education Karl Ferdinand Braun was born on 6 June 1850 at Fulda in the Kur- fürstentum [electorate princedom] Hessen as the fourth child of Jo- hann Conrad and Franziska Braun. His father Johann Conrad Braun has been actuary at the district court Fulda. In his teens he attended the Gymnasium [high school] in Fulda, and after completing the Gymnasium he enrolled in courses in mathematics and chemistry at the University Marburg. After two semesters he moved to Berlin where he focused on Physics.8 Professor Georg Hermann Quincke gave him an assistantship at the Gewerbeakademie Charlottenburg. He worked on his PhD under Quincke’s supervision and received his doctor’s degree in March 1872 with a thesis on the oscillations of elas- tic strings from the University Berlin, where Hermann von Helmholtz has been his examiner. The birth of semiconductor electronics In early 1872, when Georg Quincke was appointed as Professor at the University Würzburg, Ferdinand Braun followed him there as an assistant. In Würzburg the research activities of Ferdinand Braun mainly were focused on problems of electric conductivity. In the first 4 F. Kurylo, Ferdinand Braun (Moos, 1965). 5 F. Hars, Ferdinand Braun (1850-1918). Ein wilhelminischer Physiker (Berlin, 1999). 6 G. Wolfschmidt, Von Hertz zum Handy – Entwicklung der Kommunikation (Norderstedt, 2007). 7 G. Schmucker, “Jonathan Zenneck: 1871-1959; eine technischwissenschaftliche Biographie”, Ph.D. dissertation, University of Stuttgart, 1999. 8 Hars, Ferdinand Braun (1850-1918). 229 FERDINAND Braun. A PIONEER IN WIRELESS technology AND electronics of these works he investigated the conductivity of melted salts9 and a second paper dealt with the unipolar electric conduction through gas layers of variable conductivity.10 Ferdinand Braun’s interest in electri- cal conductivity of metal salts led him to the investigation of copper sulfide crystals. In the paper with the title “Ueber die Stromleitung durch Schwefelmetalle” [About the conduction of current through metal sulfides], submitted to Annalen der Physik und Chemie on 23 November 1874, he reported the observation that the electrical re- sistance of various natural and synthetic metal sulfide samples was dependent on direction, intensity and duration of the electrical cur- rent. The disparity of the currents has been up to 30 percent.11 He also observed, that in one direction the electrical resistance increased with decreasing current intensity and that the effect was depending on how the metallic contacts were applied to the metal sulfide sample. These effects could not be explained on the basis of existing theories. Per- forming his experiments accurately and repeatedly he could foreclose any error in measurement. After working two years with Quincke, he accepted in fall 1874 a safe and well-paid teaching appointment to the St. Thomas Gymnasi- um in Leipzig. However, also during his engagement as a Gymnasium teacher he tried to continue his scientific work. In the following, several researchers investigated the unipolar conductivity under different conditions and with other materials and got similar results. Werner Siemens obtained similar results with selenium if both electrodes applied to the crystal differed con- siderably in size.12 Other researchers could not find unipolar con- duction. Braun reacted on this with a paper about the deviations from Ohm’s law in solids with metallic conductivity.13 In this paper he concluded In general the anomalous effects occur in the easiest way if at least one electrode is small. Therefore in the majority of cases I have used as the one electrode a wire which has been pressed by a spiral spring enclosed in a bushing against the crystal. 9 F. Braun, “Ueber die galvanische Leitungsfähigkeit geschmolzener Salze”, Annalen der Physik, 230(1875), 2, pp. 161-196. 10 F. Braun, “Ueber die unipolare Elektricitätsleitung durch Gasschichten von verschiedener Leitungs- fahigkeit”, Annalen der Physik und Chemie, 230(1875), 4. 11 Braun, “Ueber die Stromleitung durch Schwefelmetalle”. 12 W. Siemens, “Ueber die Abhängigkeit der electrischen Leitungsfähigkeit des Selens von Wärme und Licht”, Annalen der Physik, vol. 238, no. 12, pp. 521–550, 1877. 13 F. Braun, “Ueber Abweichungen vom Ohm'schen Gesetz in metallisch leitenden Körpern”, Annalen der Physik, 237(1877), 5, pp. 95-110. 230 FERDINAND Braun. A PIONEER IN WIRELESS technology AND electronics Depending on the steadiness of the material a pressure of up to one kilo has been applied. In other experiments a mercury contact has been chosen. In further experiments the crystal surface has been covered galvanoplastically with a thin copper layer and this has been overlayed with mercury. The effects are mostly, if not always, determined by the junction region. At this place a very considerable current dependent resistance is localized. Thus Ferdinand Braun has discovered the point contact rectifier -ef fect and by this way created the whisker diode. In14 Ferdinand Braun reported experimental investigations of unipolar conduction on psilo- melane, a hard black manganese oxide. For his experiments he used psilomelane plates mounted in a screw clamp, isolated from the clamp, so that only the peak of the clamp exhibited electrical contact to the psilomelane plate. At this time unipolar conductivity has had no technical application, and also the physical laws governing this effect have not been known for the next fifty years. However, with his experiments performed with copper sulfide and other materials Ferdinand Braun has been the first one who has reported rectifying action of a semiconductor barrier. Fer- dinand Braun’s work marks the beginning of solid state electronics.15 He never has applied this effect to realize any device and he never has claimed this, but he has opened a new branch of science, which yielded the first sensitive radio wave detectors twenty years later and today’s semiconductor electronics. The first one who has constructed and applied a semiconductor rectifier for the detection of electromagnetic waves has been Jagadis Chandra Bose, Professor of physics at the Presidency College in Kol- kata, India. He used galena (lead sulfide) crystals contacted by a metal wire to detect millimeter waves. He reported this invention in the April 27, 1899, meeting of the Royal Society, London,16 and filed 1901 a U.S 14 F. Braun,
Load more

Recommended publications
  • Dr. Julie Brown, CTO of UDC, Awarded Prestigious 2020 Karl Ferdinand Braun Prize from the Society of Information Display
    8/3/2020 Dr. Julie Brown, CTO of UDC, Awarded Prestigious 2020 Karl Ferdinand Braun Prize from the Society of Information Display Dr. Mike Weaver, VP of UDC, Honored with 2020 SID Fellow Award EWING, N.J.--(BUSINESS WIRE)-- Universal Display Corporation (Nasdaq: OLED), enabling energy-efficient displays and lighting with its UniversalPHOLED® technology and materials, today announced that Dr. Julie Brown, Senior Vice President and Chief Technical Officer, was awarded the 2020 Karl Ferdinand Braun Prize by the Society of Information Display (SID). Additionally, Dr. Mike Weaver, Vice President of PHOLED R&D, was named a 2020 SID Fellow. The Karl Ferdinand Braun Prize was awarded to Dr. Brown for her outstanding technical achievements and contributions to the development and commercialization of phosphorescent OLED materials and display technology. The Society for Information Display created this prize in 1987 in honor of the German physicist and Nobel Laureate Karl Ferdinand Braun who invented the cathode-ray tube (CRT). Dr. Brown has been a leading innovator in the discovery and development of state-of-the-art OLED technologies and materials for display and lighting applications for over two decades, and is the first woman to be awarded this prestigious prize. Joining Universal Display (UDC) in 1998, Dr. Brown leads a global team of unique chemists, physicists and engineers and spearheads the R&D vision of UDC, from its start-up years to its successful commercial present, and continues to create and shape the Company’s innovation strategy for its future growth. The distinction of Fellow honors an SID member of outstanding qualifications and experience as a scientist or engineer in the field of information display.
    [Show full text]
  • Von Richthofen, Einstein and the AGA Estimating Achievement from Fame
    Von Richthofen, Einstein and the AGA Estimating achievement from fame Every schoolboy has heard of Einstein; fewer have heard of Antoine Becquerel; almost nobody has heard of Nils Dalén. Yet they all won Nobel Prizes for Physics. Can we gauge a scientist’s achievements by his or her fame? If so, how? And how do fighter pilots help? Mikhail Simkin and Vwani Roychowdhury look for the linkages. “It was a famous victory.” We instinctively rank the had published. However, in 2001–2002 popular French achievements of great men and women by how famous TV presenters Igor and Grichka Bogdanoff published they are. But is instinct enough? And how exactly does a great man’s fame relate to the greatness of his achieve- ment? Some achievements are easy to quantify. Such is the case with fighter pilots of the First World War. Their achievements can be easily measured and ranked, in terms of their victories – the number of enemy planes they shot down. These aces achieved varying degrees of fame, which have lasted down to the internet age. A few years ago we compared1 the fame of First World War fighter pilot aces (measured in Google hits) with their achievement (measured in victories); and we found that We can estimate fame grows exponentially with achievement. fame from Google; Is the same true in other areas of excellence? Bagrow et al. have studied the relationship between can this tell us 2 achievement and fame for physicists . The relationship Manfred von Richthofen (in cockpit) with members of his so- about actual they found was linear.
    [Show full text]
  • THE DIRECTOR with REFERENCE to The
    SETTORE SELEZIONE E CONTRATTI UFFICIO RICERCATORI A TEMPO DETERMINATO THE DIRECTOR WITH REFERENCE TO the rules referred to in Article 14 of the present call for application ORDERS Art. 1 – Purpose A procedure of comparative evaluation by qualifications and public discussion is called for the recruitment of 1 researcher with a fixed-term employment contract full-time for the three-year - pursuant to art. 24 paragraph 3 letter b) (senior) of Law no. 240/2010 -. Sector competition reference 02/C1 - Astronomy, Astrophysics, Earth and Planetary Physics, Scientific sector FIS/06 - Physics of The Earth and of The Circumterrestrial Medium. The job is activated for the needs of research and study of the Department of Physics and Astronomy "Augusto Righi" - DIFA. Serving primarily at the Department of Physics and Astronomy "Augusto Righi" - DIFA, in Bologna. The contract shall last three years. An annual gross total amount equal to € 42.880,00. The annual increase in this amount will be calculated according to the existing procedure for non-contracted personnel. Art. 2 – Activities to be performed The contract includes 350 hours of supplementary teaching and assistance to students, for each academic year covered by the contract. The contract shall schedule 60 hours of teaching on annual basis. Concerning the provisions of art. 10 regarding fixed term researchers, issued by Rectoral Decree no. 344 of 29/03/2011 and amendments, the researcher’s activities must be linked to the development of the project entitled: “Evaluation of the effectiveness of innovative nature-based solutions to mitigate the risks associated with climate change". The candidate will be responsible for coordinating and supporting the implementation of NBS catalogs in OPERANDUM's GeoIKP platform.
    [Show full text]
  • Practical Design of HF- VHF – Antennas!
    ANTENTOP 01 2003 # 002 ANTENTOP is FREE e-magazine devoted to ANTENnas Theory, Operation, and Practice Edited by hams for hams In the Issue: Thanks to our authors: Practical design of HF- VHF – Prof. Natalia K.Nikolova Antennas! John S. Belrose, VE2CV James P. Rybak Antennas Theory! Leonid Kryzhanovsky Alexey EW1LN Sergey A. Kovalev, USONE Propagation Mysteries! John Doty Robert Brown, NM7M History Early Radio! Michael Higgins, EI 0 CL Dick Rollema, PAOSE And More…. Peter Dodd, G3LDO And others….. EDITORIAL: Well, ANTENTOP # 001 come in! ANTENTOP is just authors’ opinions in the world of amateur radio. I do not correct and re-edit your articles, the articles are printed “as is”. A little note, I am not a native English, so, of course, there are some sentence and grammatical mistakes there… Please, be indulgent! (continued on next page) 73! Igor Grigorov, RK3ZK ex: UA3-117-386, UA3ZNW, UA3ZNW/UA1N, UZ3ZK op: UK3ZAM, UK5LAP, EN1NWB, EN5QRP, EN100GM Copyright: Here at ANTENTOP we just Contact us: Just email me or wanted to follow traditions of FREE flow of drop a letter. information in our great radio hobby around the world. A whole issue of Mailing address: ANTENTOP may be photocopied, printed, pasted onto websites. We don't want to Box 68, 308015, Belgorod, Russia control this process. It comes from all of Email: [email protected] us, and thus it belongs to all of us. This doesn't mean that there are no copyrights. NB: Please, use only plain text and mark email subject as: There is! Any work is copyrighted by the igor_ant.
    [Show full text]
  • Dissertation (1.448Mb)
    Milk revolution and the homogeneous New Zealand coffee market Guo Jingsi 2020 Faculty of Culture and Society A dissertation submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Hospitality Supervisor Dr. Lindsay Neill i Abstract It is unsurprising that, as an enjoyable and social beverage, coffee has generated a coffee culture in Aotearoa New Zealand. Part of coffee’s enjoyment and culture is the range of milk types available for milk-based coffees. That range has grown in recent years. A2 Milk is a recent addition to that offering. The A2 Milk Company has experienced exceptional growth. However, my own experience as a coffee consumer in Auckland, Aotearoa New Zealand, has revealed that A2 Milk is not a milk that is commonly offered in many of the city’s cafés. Consequently, my research explores that lack and barista perceptions of A2 Milk within my research at The Coffee Club in Auckland’s Onehunga. As a franchise outlet, The Coffee Club constitutes a representative sample of a wider cohort, the 60 Coffee Clubs spread throughout Aotearoa New Zealand. While my research reinforces much of the knowledge about coffee culture in Aotearoa New Zealand, my emphasis on the influence of A2 Milk within that culture has revealed some interesting new insights. As my five professional barista participants at the Coffee Club revealed, rather than taking a proactive approach to A2 Milk, they were ‘waiting’ for one of two occurrences before considering the offering of A2 Milk. Those considerations included a ‘push’ from the A2 Milk Company that promoted A2 Milk within coffee culture.
    [Show full text]
  • Nanoscience Education
    Livre de Lyon Academic Works of Livre de Lyon Educational Sciences 2020 NANOSCIENCE EDUCATION Ruhan Benlikaya Balikesir University, [email protected] Follow this and additional works at: https://academicworks.livredelyon.com/edu_sci Part of the Education Commons Recommended Citation Benlikaya, Ruhan, "NANOSCIENCE EDUCATION" (2020). Educational Sciences. 35. https://academicworks.livredelyon.com/edu_sci/35 This Book is brought to you for free and open access by Livre de Lyon, an international publisher specializing in academic books and journals. Browse more titles on Academic Works of Livre de Lyon, hosted on Digital Commons, an Elsevier platform. For more information, please contact [email protected]. ACADEMIC STUDIES IN EDUCATIONAL SCIENCES Editor Prof. Dr. Hulya GUR Lyon 2020 Editor • Prof. Dr. Hulya GUR 0000-0001-8479-8811 Cover Design • Aruull Raja First Published • December 2020, Lyon ISBN: 978-2-38236-041-5 © copyright All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by an means, electronic, mechanical, photocopying, recording, or otherwise, without the publisher’s permission. The chapters in this book have been checked for plagiarism by Publisher • Livre de Lyon Address • 37 rue marietton, 69009, Lyon France website • http://www.livredelyon.com e-mail • [email protected] PREFACE This book provides a detailed and up-to-date overview of works in education, science and mathematics education. This book is informative for especially educators, reseachers, academics, postgraduate students, preservive teachers, teachers and school leaders own development. It gives suggestions to educators, reseachers, academics, postgraduate students, preservive teachers, teachers, school leadersand policy makers and so on..
    [Show full text]
  • THE DIRECTOR with REFERENCE to The
    SETTORE SELEZIONE E CONTRATTI UFFICIO RICERCATORI A TEMPO DETERMINATO THE DIRECTOR WITH REFERENCE TO the rules referred to in Article 14 of the present call for application ORDERS Art. 1 – Purpose A procedure of comparative evaluation by qualifications and public discussion is called for the recruitment of 1 researcher with a fixed-term employment contract full-time for the three-year - pursuant to art. 24 paragraph 3 letter a) (junior) of Law no. 240/2010 - Sector competition reference 02/A1 - Experimental Physics of Fundamental Interactions, Scientific sector FIS/01 - Experimental Physics. The job is activated for the needs of research and study of the Department of Physics and Astronomy "Augusto Righi" - DIFA of the Alma Mater Studiorum - Università di Bologna. Serving primarily at the Department Physics and Astronomy "Augusto Righi" - DIFA, in Bologna. The contract shall last three years. An annual gross total amount equal to € 35.733,00. The annual increase in this amount will be calculated according to the existing procedure for non-contracted personnel. Art. 2 – Activities to be performed The contract includes 350 hours of supplementary teaching and assistance to students, for each academic year covered by the contract. The contract shall schedule 60 hours of teaching on annual basis. Concerning the provisions of art. 10 regarding fixed term researchers, issued by Rectoral Decree no. 344 of 29/03/2011 and amendments, the researcher’s activities must be linked to the development of the project entitled: “High-precision measurements of CP violation and the CKM matrix parameters with the LHCb-upgrade data, at the CERN Large Hadron Collider”, co-financed by the Istituto Nazionale di Fisica Nucleare - INFN.
    [Show full text]
  • AWAR Volume 24.Indb
    THE AWA REVIEW Volume 24 2011 Published by THE ANTIQUE WIRELESS ASSOCIATION PO Box 421, Bloomfi eld, NY 14469-0421 http://www.antiquewireless.org i Devoted to research and documentation of the history of wireless communications. Antique Wireless Association P.O. Box 421 Bloomfi eld, New York 14469-0421 Founded 1952, Chartered as a non-profi t corporation by the State of New York. http://www.antiquewireless.org THE A.W.A. REVIEW EDITOR Robert P. Murray, Ph.D. Vancouver, BC, Canada ASSOCIATE EDITORS Erich Brueschke, BSEE, MD, KC9ACE David Bart, BA, MBA, KB9YPD FORMER EDITORS Robert M. Morris W2LV, (silent key) William B. Fizette, Ph.D., W2GDB Ludwell A. Sibley, KB2EVN Thomas B. Perera, Ph.D., W1TP Brian C. Belanger, Ph.D. OFFICERS OF THE ANTIQUE WIRELESS ASSOCIATION DIRECTOR: Tom Peterson, Jr. DEPUTY DIRECTOR: Robert Hobday, N2EVG SECRETARY: Dr. William Hopkins, AA2YV TREASURER: Stan Avery, WM3D AWA MUSEUM CURATOR: Bruce Roloson W2BDR 2011 by the Antique Wireless Association ISBN 0-9741994-8-6 Cover image is of Ms. Kathleen Parkin of San Rafael, California, shown as the cover-girl of the Electrical Experimenter, October 1916. She held both a commercial and an amateur license at 16 years of age. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner. Printed in Canada by Friesens Corporation Altona, MB ii Table of Contents Volume 24, 2011 Foreword ....................................................................... iv The History of Japanese Radio (1925 - 1945) Tadanobu Okabe .................................................................1 Henry Clifford - Telegraph Engineer and Artist Bill Burns ......................................................................
    [Show full text]
  • Communications-Mathematics and Applied Mathematics/Download/8110
    A Mathematician's Journey to the Edge of the Universe "The only true wisdom is in knowing you know nothing." ― Socrates Manjunath.R #16/1, 8th Main Road, Shivanagar, Rajajinagar, Bangalore560010, Karnataka, India *Corresponding Author Email: [email protected] *Website: http://www.myw3schools.com/ A Mathematician's Journey to the Edge of the Universe What’s the Ultimate Question? Since the dawn of the history of science from Copernicus (who took the details of Ptolemy, and found a way to look at the same construction from a slightly different perspective and discover that the Earth is not the center of the universe) and Galileo to the present, we (a hoard of talking monkeys who's consciousness is from a collection of connected neurons − hammering away on typewriters and by pure chance eventually ranging the values for the (fundamental) numbers that would allow the development of any form of intelligent life) have gazed at the stars and attempted to chart the heavens and still discovering the fundamental laws of nature often get asked: What is Dark Matter? ... What is Dark Energy? ... What Came Before the Big Bang? ... What's Inside a Black Hole? ... Will the universe continue expanding? Will it just stop or even begin to contract? Are We Alone? Beginning at Stonehenge and ending with the current crisis in String Theory, the story of this eternal question to uncover the mysteries of the universe describes a narrative that includes some of the greatest discoveries of all time and leading personalities, including Aristotle, Johannes Kepler, and Isaac Newton, and the rise to the modern era of Einstein, Eddington, and Hawking.
    [Show full text]
  • November 2019
    A selection of some recent arrivals November 2019 Rare and important books & manuscripts in science and medicine, by Christian Westergaard. Flæsketorvet 68 – 1711 København V – Denmark Cell: (+45)27628014 www.sophiararebooks.com AMPÈRE, André-Marie. THE FOUNDATION OF ELECTRO- DYNAMICS, INSCRIBED BY AMPÈRE AMPÈRE, Andre-Marie. Mémoires sur l’action mutuelle de deux courans électri- ques, sur celle qui existe entre un courant électrique et un aimant ou le globe terres- tre, et celle de deux aimans l’un sur l’autre. [Paris: Feugeray, 1821]. $22,500 8vo (219 x 133mm), pp. [3], 4-112 with five folding engraved plates (a few faint scattered spots). Original pink wrappers, uncut (lacking backstrip, one cord partly broken with a few leaves just holding, slightly darkened, chip to corner of upper cov- er); modern cloth box. An untouched copy in its original state. First edition, probable first issue, extremely rare and inscribed by Ampère, of this continually evolving collection of important memoirs on electrodynamics by Ampère and others. “Ampère had originally intended the collection to contain all the articles published on his theory of electrodynamics since 1820, but as he pre- pared copy new articles on the subject continued to appear, so that the fascicles, which apparently began publication in 1821, were in a constant state of revision, with at least five versions of the collection appearing between 1821 and 1823 un- der different titles” (Norman). The collection begins with ‘Mémoires sur l’action mutuelle de deux courans électriques’, Ampère’s “first great memoir on electrody- namics” (DSB), representing his first response to the demonstration on 21 April 1820 by the Danish physicist Hans Christian Oersted (1777-1851) that electric currents create magnetic fields; this had been reported by François Arago (1786- 1853) to an astonished Académie des Sciences on 4 September.
    [Show full text]
  • Design Patenting by Organizations, CY 2013
    DESIGN PATENTING BY ORGANIZATIONS 2013 March 2014 U.S. PATENT AND TRADEMARK OFFICE ELECTRONIC INFORMATION PRODUCTS DIVISION - PTMT P.O. BOX 1450 ALEXANDRIA, VA 22313-1450 tel (571) 272-5600 / FAX (571) 273-0110 A PATENT TECHNOLOGY MONITORING TEAM REPORT Design Patenting By Organizations 2013 This report, prepared from the Technology Assessment and Forecast (TAF) database, profiles design patents granted during calendar year 2013. Part A1 Part A1 presents patent counts by origin, U.S. and foreign. Individual counts are also presented for each of the top 36 patenting countries. Patent origin is determined by the residence of the first-named inventor listed on a patent. Patent ownership-category information reflects ownership at the time of patent grant and does not reflect subsequent changes in ownership. If more than one assignee (the entity, if any, to which the patent rights have been legally assigned) was declared at the time of grant, a patent is attributed to the ownership-category of the first-named assignee. The "U.S. Corporations" and "Foreign Corporations" ownership categories count predominantly corporate patents; however, patents assigned to other organizations such as small businesses, nonprofit organizations, universities, etc. are also included in these categories. While the "U.S. Government" ownership category includes only patents granted to the Federal Government, no such distinction is made for the "Foreign Government" ownership category. The "U.S. Individuals" and "Foreign Individuals" ownership categories include patents for which ownership was assigned to an individual as well as patents for which no assignment of ownership was made at the time of grant (i.e., ownership was retained by the inventor(s)).
    [Show full text]
  • Magnets in Particle Physics
    MAGNETS IN PARTICLE PHYSICS F. Bonaudi CERN, Geneva, Switzerland Abstract This review talk introduces a week of specialized lectures on all aspects of magnet design and construction. The programme includes theory, materials, measurements, alignment and some particular applications: it is therefore a very complete coverage of the field and will certainly shed a lot of new light on the subject. Rather than entering into any of these specialized areas, the present lecture will try to present a broad survey of the applications of magnets to particle physics research, and will include a section on the historical developments that led to our present understanding of magnetic phenomena. 1 . ACCELERATORS, DETECTORS AND (ELECTRO)MAGNETS In modern times it is hardly conceivable to design a particle accelerator without resorting to the use of magnets. By "magnets" we almost exclusively mean electromagnets, although permanent magnets have had applications too. In the past these were mainly for vacuum pumps and gauges of various sorts, or for sweeping magnets. It is very encouraging to see that in the last ten years or so permanent magnets have started to be used for focussing (quadrupole) magnetic devices. In fact, one session of this Accelerator School deals with permanent magnets. Particle detectors very often incorporate an analyzing magnet in order to measure the momentum of charged secondary particles by track curvature. The most recent applications in colliding beam experiments have all adopted a solenoidal field geometry coaxial with the (mean) beam direction. It should be recalled that particle "observation" nowadays is done exclusively by electronic means, therefore the "tracking" information is provided by many small sensitive elements (wires, pads, pixels, fibres etc.) and the reconstruction computer programs make a tit to a continuous curve (circle or helix).
    [Show full text]