DOCSLIB.ORG

The International System of Units (SI), 2019 Edition

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The International System of Units (SI), 2019 Edition NIST Special Publication 330 SP 330 The International System of Units (SI) 2019 David B. Newell and Eite Tiesinga, Editors EDITION This publication is available free of charge https://doi.org/10.6028/NIST.SP.330-2019 This publication is available fr ee of charge from: https://doi. INSIDE FRONT COVER - BLANK org/10.6028/NIST.SP.330-2019 org/10.6028/NIST.SP.330-2019 NIST Special Publication 330 2019 EDITION The International System of Units (SI) United States version of the English text of the ninth edition (2019) of the International Bureau of Weights and Measures publication Le Système International d’ Unités (SI) (Supersedes NIST Special Publication 330, 2008 Edition) Editors: David B. Newell Eite Tiesinga Physical Measurement Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 This publication is available free of charge from: https://doi.org/10.6028/NIST.SP.330-2019 August 2019 U.S. Department of Commerce Wilbur L. Ross, Jr., Secretary National Institute of Standards and Technology Walter Copan, NIST Director and Undersecretary of Commerce for Standards and Technology Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. This publication is available free of charge from: National Institute of Standards and Technology Special Publication 330 Natl. Inst. Stand. Technol. Spec. Publ. 330, 122 pages (August 2019) CODEN: NSPUE2 This publication is available free of charge from: https://doi.org/10.6028/NIST.SP.330-2019 https://doi.org /10.6028/NIST.SP .330 - 2019 Foreword The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. The SI is the dominant measurement system used in science and international commerce. In recognition of this fact, Congress has designated the metric system of measurement as the preferred system of weights and measures for United States trade and commerce. This publication is available free of charge from: The definitive international reference on the SI is a booklet published by the International Bureau of Weights and Measures (BIPM, Bureau International des Poids et Mesures) and often referred to as the BIPM SI Brochure. Entitled Le Système International d' Unités (SI), the booklet is in French followed by a text in English. This 2019 edition of the National Institute of Standards and Technology (NIST) Special Publication (SP) 330 is the United States version of the English text of the ninth edition of the Brochure (the most current) published in 2019. The 2019 edition of NIST SP 330 replaces its immediate predecessor, the 2008 edition, which was based on the eighth edition of the BIPM SI Brochure published in 2006, updated in 2014. The Secretary of Commerce acting through the Director of the NIST is authorized by statute (§15 U.S.C. 272) under subsection (2) “to develop, maintain, and retain custody of the national standards of measurement, and provide the means and methods for making measurements consistent with those standards” and under subsection (9) “to assure the compatibility of United States national measurement standards with those of other nations.” Under this authority, the SI is interpreted or modified by the Director of NIST https://doi.org for use in the United States. The Secretary of Commerce acting through the NIST Director is designated to direct and coordinate efforts by Federal departments and agencies to implement Government metric usage in accordance the Metric Conversion Act (15 U.S.C. 205b), as amended by the Omnibus Trade and Competitiveness Act of /10.6028/NIST.SP. 1988. Like its 2008 predecessor, the 2019 edition of NIST SP 330 conforms with the English text in the BIPM SI Brochure but contains a few minor differences to reflect the most recent interpretation of the SI for the United States by the Secretary of Commerce, as published in the Federal Register. These differences include the following: 330 • The spelling of English words is in accordance with the United States - Government Printing Office Style Manual, which follows Webster's Third New 2019 International Dictionary rather than the Oxford Dictionary. Thus the spellings “meter,” “liter,” “deka,” and “cesium” are used rather than “metre,” “litre,” “deca,” and “caesium” as in the original BIPM English text. • The name of the unit with symbol t and defined according to 1 t = 103 kg is called “metric ton” rather than “tonne.” • Since the preferred unit symbol for the liter in the United States is L, only L is given as the symbol for the liter. • A number of “Editors’ notes” are added in order to indicate such differences where significant (except spelling differences) and to clarify the text; and iii • A few very minor editorial changes are made in order to “Americanize” some phrases. Because of the importance of the SI to science, technology, and commerce, and because NIST (i) coordinates the Federal Government policy on the conversion to the SI by Federal agencies and on the use of the SI by U.S. industry, (ii) provides official U.S. representation in the various international bodies established by the Meter Convention (see p. 1), and (iii) is responsible for interpreting and modifying the SI for use in the This publication is available free of charge from: United States, NIST provides a number of other sources of information on the SI in addition to NIST SP 330. This includes NIST Special Publication 811, Guide for the Use of the International System of Units (SI), by David B. Newell and Eite Tiesinga. NIST SP 330, NIST SP 811, the aforementioned Federal Register notice are the essential elements of the U.S. interpretation of the SI. Users of this NIST publication are encouraged to take advantage of the resources, useful links, and other information available on the BIPM (www.bipm.org) and NIST Metric Program (www.nist.gov/metric) websites. August 2019 David B. Newell https://doi.org Eite Tiesinga Note from the BIPM on copyright and the use of the English text: /10.6028/NIST.SP. “All BIPM’s works are internationally protected by copyright. This document has been drafted with permission obtained from the BIPM. The only official text is the French text of the original document created by the BIPM.” To make its work more widely accessible, the International Committee for Weights and Measures (CIPM) has decided to publish an English version of its reports. Readers should 330 note that the official record is always that of the French text. This must be used when an - authoritative reference is required or when there is doubt about the interpretation of the 2019 text. iv The BIPM and the Meter Convention The International Bureau of Weights and Measures (BIPM) was set up by As of 20 May 2019 there the Meter Convention signed in Paris on 20 May 1875 by seventeen States were fifty nine Member during the final session of the diplomatic Conference of the Meter. This States: Argentina, Australia, Convention was amended in 1921. Austria, Belgium, Brazil, Bulgaria, Canada, Chile, The BIPM has its headquarters near Paris, in the grounds (43 520 m2) of the China, Colombia, Croatia, This publication is available free of charge from: Pavillon de Breteuil (Parc de Saint-Cloud) placed at its disposal by the Czech Republic, Denmark, French Government; its upkeep is financed jointly by the Member States of Egypt, Finland, France, Germany, Greece, Hungary, the Meter Convention. India, Indonesia, Iran The task of the BIPM is to ensure worldwide unification of measurements; (Islamic Rep. of), Iraq, Ireland, Israel, Italy, Japan, its objectives are to: Kazakhstan, Kenya, Korea (Republic of), Lithuania, • represent the world-wide measurement community, aiming to Malaysia, Mexico, maximize its uptake and impact, Montenegro, Netherlands, New Zealand, Norway, • be a center for scientific and technical collaboration between Member Pakistan, Poland, Portugal, States, providing capabilities for international measurement Romania, Russian comparisons on a shared-cost basis, Federation, Saudi Arabia, Serbia, Singapore, Slovakia, • be the coordinator of the world-wide measurement system, ensuring it Slovenia, South Africa, gives comparable and internationally accepted measurement results. Spain, Sweden, Switzerland, Thailand, Tunisia, Turkey, Ukraine, United Arab Emirates, United Kingdom, https://doi.org The BIPM operates under the exclusive supervision of the International Committee for Weights and Measures (CIPM) which itself comes under the United States of America and authority of the General Conference on Weights and Measures (CGPM) and Uruguay reports to it on the work accomplished by the BIPM. Forty-two States and Economies were Associates /10.6028/NIST.SP. Delegates from all Member States attend the General Conference, which of the General Conference: normally meets every four years. The function of these meetings is to: Albania, Azerbaijan, Bangladesh, Belarus, Bolivia, • discuss and initiate the arrangements required to ensure the Bosnia and Herzegovina, propagation and improvement of the International System of Units Botswana, CARICOM, Chinese Taipei, Costa Rica, (SI), which is the modern form of the metric system; Cuba, Ecuador, Estonia, • confirm the results
Load more

Recommended publications
  • Lecture 3: the Sensor
    4.430 Daylighting Human Eye ‘HDR the old fashioned way’ (Niemasz) Massachusetts Institute of Technology ChriChristoph RstophReeiinhartnhart Department of Architecture 4.4.430 The430The SeSensnsoror Building Technology Program Happy Valentine’s Day Sun Shining on a Praline Box on February 14th at 9.30 AM in Boston. 1 Happy Valentine’s Day Falsecolor luminance map Light and Human Vision 2 Human Eye Outside view of a human eye Ophtalmogram of a human retina Retina has three types of photoreceptors: Cones, Rods and Ganglion Cells Day and Night Vision Photopic (DaytimeVision): The cones of the eye are of three different types representing the three primary colors, red, green and blue (>3 cd/m2). Scotopic (Night Vision): The rods are repsonsible for night and peripheral vision (< 0.001 cd/m2). Mesopic (Dim Light Vision): occurs when the light levels are low but one can still see color (between 0.001 and 3 cd/m2). 3 VisibleRange Daylighting Hanbook (Reinhart) The human eye can see across twelve orders of magnitude. We can adapt to about 10 orders of magnitude at a time via the iris. Larger ranges take time and require ‘neural adaptation’. Transition Spaces Outside Atrium Circulation Area Final destination 4 Luminous Response Curve of the Human Eye What is daylight? Daylight is the visible part of the electromagnetic spectrum that lies between 380 and 780 nm. UV blue green yellow orange red IR 380 450 500 550 600 650 700 750 wave length (nm) 5 Photometric Quantities Characterize how a space is perceived. Illuminance Luminous Flux Luminance Luminous Intensity Luminous Intensity [Candela] ~ 1 candela Courtesy of Matthew Bowden at www.digitallyrefreshing.com.
    [Show full text]
  • Units and Conversions
    Units and Conversions This unit of the Metrology Fundamentals series was developed by the Mitutoyo Institute of Metrology, the educational department within Mitutoyo America Corporation. The Mitutoyo Institute of Metrology provides educational courses and free on-demand resources across a wide variety of measurement related topics including basic inspection techniques, principles of dimensional metrology, calibration methods, and GD&T. For more information on the educational opportunities available from Mitutoyo America Corporation, visit us at www.mitutoyo.com/education. This technical bulletin addresses an important aspect of the language of measurement – the units used when reporting or discussing measured values. The dimensioning and tolerancing practices used on engineering drawings and related product specifications use either decimal inch (in) or millimeter (mm) units. Dimensional measurements are therefore usually reported in either of these units, but there are a number of variations and conversions that must be understood. Measurement accuracy, equipment specifications, measured deviations, and errors are typically very small numbers, and therefore a more practical spoken language of units has grown out of manufacturing and precision measurement practice. Metric System In the metric system (SI or International System of Units), the fundamental unit of length is the meter (m). Engineering drawings and measurement systems use the millimeter (mm), which is one thousandths of a meter (1 mm = 0.001 m). In general practice, however, the common spoken unit is the “micron”, which is slang for the micrometer (m), one millionth of a meter (1 m = 0.001 mm = 0.000001 m). In more rare cases, the nanometer (nm) is used, which is one billionth of a meter.
    [Show full text]
  • Light and Illumination
    ChapterChapter 3333 -- LightLight andand IlluminationIllumination AAA PowerPointPowerPointPowerPoint PresentationPresentationPresentation bybyby PaulPaulPaul E.E.E. Tippens,Tippens,Tippens, ProfessorProfessorProfessor ofofof PhysicsPhysicsPhysics SouthernSouthernSouthern PolytechnicPolytechnicPolytechnic StateStateState UniversityUniversityUniversity © 2007 Objectives:Objectives: AfterAfter completingcompleting thisthis module,module, youyou shouldshould bebe ableable to:to: •• DefineDefine lightlight,, discussdiscuss itsits properties,properties, andand givegive thethe rangerange ofof wavelengthswavelengths forfor visiblevisible spectrum.spectrum. •• ApplyApply thethe relationshiprelationship betweenbetween frequenciesfrequencies andand wavelengthswavelengths forfor opticaloptical waves.waves. •• DefineDefine andand applyapply thethe conceptsconcepts ofof luminousluminous fluxflux,, luminousluminous intensityintensity,, andand illuminationillumination.. •• SolveSolve problemsproblems similarsimilar toto thosethose presentedpresented inin thisthis module.module. AA BeginningBeginning DefinitionDefinition AllAll objectsobjects areare emittingemitting andand absorbingabsorbing EMEM radiaradia-- tiontion.. ConsiderConsider aa pokerpoker placedplaced inin aa fire.fire. AsAs heatingheating occurs,occurs, thethe 1 emittedemitted EMEM waveswaves havehave 2 higherhigher energyenergy andand 3 eventuallyeventually becomebecome visible.visible. 4 FirstFirst redred .. .. .. thenthen white.white. LightLightLight maymaymay bebebe defineddefineddefined
    [Show full text]
  • Consultative Committee for Amount of Substance; Metrology in Chemistry and Biology CCQM Working Group on Isotope Ratios (IRWG) S
    Consultative Committee for Amount of Substance; Metrology in Chemistry and Biology CCQM Working Group on Isotope Ratios (IRWG) Strategy for Rolling Programme Development (2021-2030) 1. EXECUTIVE SUMMARY In April 2017, the Consultative Committee for Amount of Substance; Metrology in Chemistry and Biology (CCQM) established a task group to study the metrological state of isotope ratio measurements and to formulate recommendations to the Consultative Committee (CC) regarding potential engagement in this field. In April 2018 the Isotope Ratio Working Group (IRWG) was established by the CCQM based on the recommendation of the task group. The main focus of the IRWG is on the stable isotope ratio measurement science activities needed to improve measurement comparability to advance the science of isotope ratio measurement among National Metrology Institutes (NMIs) and Designated Institutes (DIs) focused on serving stake holder isotope ratio measurement needs. During the current five-year mandate, it is expected that the IRWG will make significant advances in: i. delta scale definition, ii. measurement comparability of relative isotope ratio measurements, iii. comparable measurement capabilities for C and N isotope ratio measurement; and iv. the understanding of calibration modalities used in metal isotope ratio characterization. 2. SCIENTIFIC, ECONOMIC AND SOCIAL CHALLENGES Isotopes have long been recognized as markers for a wide variety of molecular processes. Indeed, applications where isotope ratios are used provide scientific, economic, and social value. Early applications of isotope measurements were recognized with the 1943 Nobel Prize for Chemistry which included the determination of the water content in the human body, determination of solubility of various low-solubility salts, and development of the isotope dilution method which has since become the cornerstone of analytical chemistry.
    [Show full text]
  • Admittance, Conductance, Reactance and Susceptance of New Natural Fabric Grewia Tilifolia V
    Sensors & Transducers Volume 119, Issue 8, www.sensorsportal.com ISSN 1726-5479 August 2010 Editors-in-Chief: professor Sergey Y. Yurish, tel.: +34 696067716, fax: +34 93 4011989, e-mail: [email protected] Editors for Western Europe Editors for North America Meijer, Gerard C.M., Delft University of Technology, The Netherlands Datskos, Panos G., Oak Ridge National Laboratory, USA Ferrari, Vittorio, Universitá di Brescia, Italy Fabien, J. Josse, Marquette University, USA Katz, Evgeny, Clarkson University, USA Editor South America Costa-Felix, Rodrigo, Inmetro, Brazil Editor for Asia Ohyama, Shinji, Tokyo Institute of Technology, Japan Editor for Eastern Europe Editor for Asia-Pacific Sachenko, Anatoly, Ternopil State Economic University, Ukraine Mukhopadhyay, Subhas, Massey University, New Zealand Editorial Advisory Board Abdul Rahim, Ruzairi, Universiti Teknologi, Malaysia Djordjevich, Alexandar, City University of Hong Kong, Hong Kong Ahmad, Mohd Noor, Nothern University of Engineering, Malaysia Donato, Nicola, University of Messina, Italy Annamalai, Karthigeyan, National Institute of Advanced Industrial Science Donato, Patricio, Universidad de Mar del Plata, Argentina and Technology, Japan Dong, Feng, Tianjin University, China Arcega, Francisco, University of Zaragoza, Spain Drljaca, Predrag, Instersema Sensoric SA, Switzerland Arguel, Philippe, CNRS, France Dubey, Venketesh, Bournemouth University, UK Ahn, Jae-Pyoung, Korea Institute of Science and Technology, Korea Enderle, Stefan, Univ.of Ulm and KTB Mechatronics GmbH, Germany
    [Show full text]
  • The Avogadro Constant to Be Equal to Exactly 6.02214X×10 23 When It Is Expressed in the Unit Mol −1
    [august, 2011] redefinition of the mole and the new system of units zoltan mester It is as easy to count atomies as to resolve the propositions of a lover.. As You Like It William Shakespeare 1564-1616 Argentina, Austria-Hungary, Belgium, Brazil, Denmark, France, German Empire, Italy, Peru, Portugal, Russia, Spain, Sweden and Norway, Switzerland, Ottoman Empire, United States and Venezuela 1875 -May 20 1875, BIPM, CGPM and the CIPM was established, and a three- dimensional mechanical unit system was setup with the base units metre, kilogram, and second. -1901 Giorgi showed that it is possible to combine the mechanical units of this metre–kilogram–second system with the practical electric units to form a single coherent four-dimensional system -In 1921 Consultative Committee for Electricity (CCE, now CCEM) -by the 7th CGPM in 1927. The CCE to proposed, in 1939, the adoption of a four-dimensional system based on the metre, kilogram, second, and ampere, the MKSA system, a proposal approved by the ClPM in 1946. -In 1954, the 10th CGPM, the introduction of the ampere, the kelvin and the candela as base units -in 1960, 11th CGPM gave the name International System of Units, with the abbreviation SI. -in 1970, the 14 th CGMP introduced mole as a unit of amount of substance to the SI 1960 Dalton publishes first set of atomic weights and symbols in 1805 . John Dalton(1766-1844) Dalton publishes first set of atomic weights and symbols in 1805 . John Dalton(1766-1844) Much improved atomic weight estimates, oxygen = 100 . Jöns Jacob Berzelius (1779–1848) Further improved atomic weight estimates .
    [Show full text]
  • Series Impedance and Shunt Admittance Matrices of an Underground Cable System
    SERIES IMPEDANCE AND SHUNT ADMITTANCE MATRICES OF AN UNDERGROUND CABLE SYSTEM by Navaratnam Srivallipuranandan B.E.(Hons.), University of Madras, India, 1983 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES (Department of Electrical Engineering) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA, 1986 C Navaratnam Srivallipuranandan, 1986 November 1986 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date 6 n/8'i} SERIES IMPEDANCE AND SHUNT ADMITTANCE MATRICES OF AN UNDERGROUND CABLE ABSTRACT This thesis describes numerical methods for the: evaluation of the series impedance matrix and shunt admittance matrix of underground cable systems. In the series impedance matrix, the terms most difficult to compute are the internal impedances of tubular conductors and the earth return impedance. The various form u hit- for the interim!' impedance of tubular conductors and for th.: earth return impedance are, therefore, investigated in detail. Also, a more accurate way of evaluating the elements of the admittance matrix with frequency dependence of the complex permittivity is proposed.
    [Show full text]
  • Impedance Matching
    Impedance Matching Advanced Energy Industries, Inc. Introduction The plasma industry uses process power over a wide range of frequencies: from DC to several gigahertz. A variety of methods are used to couple the process power into the plasma load, that is, to transform the impedance of the plasma chamber to meet the requirements of the power supply. A plasma can be electrically represented as a diode, a resistor, Table of Contents and a capacitor in parallel, as shown in Figure 1. Transformers 3 Step Up or Step Down? 3 Forward Power, Reflected Power, Load Power 4 Impedance Matching Networks (Tuners) 4 Series Elements 5 Shunt Elements 5 Conversion Between Elements 5 Smith Charts 6 Using Smith Charts 11 Figure 1. Simplified electrical model of plasma ©2020 Advanced Energy Industries, Inc. IMPEDANCE MATCHING Although this is a very simple model, it represents the basic characteristics of a plasma. The diode effects arise from the fact that the electrons can move much faster than the ions (because the electrons are much lighter). The diode effects can cause a lot of harmonics (multiples of the input frequency) to be generated. These effects are dependent on the process and the chamber, and are of secondary concern when designing a matching network. Most AC generators are designed to operate into a 50 Ω load because that is the standard the industry has settled on for measuring and transferring high-frequency electrical power. The function of an impedance matching network, then, is to transform the resistive and capacitive characteristics of the plasma to 50 Ω, thus matching the load impedance to the AC generator’s impedance.
    [Show full text]
  • Page 1 of 29 Dalton Transactions
    Dalton Transactions Accepted Manuscript This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/dalton Page 1 of 29 Dalton Transactions Core-level photoemission spectra of Mo 0.3 Cu 0.7 Sr 2ErCu 2Oy, a superconducting perovskite derivative. Unconventional structure/property relations a, b b b a Sourav Marik , Christine Labrugere , O.Toulemonde , Emilio Morán , M. A. Alario- Manuscript Franco a,* aDpto. Química Inorgánica, Facultad de CC.Químicas, Universidad Complutense de Madrid, 28040- Madrid (Spain) bCNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac, F-33608, France
    [Show full text]
  • Guide for the Use of the International System of Units (SI)
    Guide for the Use of the International System of Units (SI) m kg s cd SI mol K A NIST Special Publication 811 2008 Edition Ambler Thompson and Barry N. Taylor NIST Special Publication 811 2008 Edition Guide for the Use of the International System of Units (SI) Ambler Thompson Technology Services and Barry N. Taylor Physics Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 (Supersedes NIST Special Publication 811, 1995 Edition, April 1995) March 2008 U.S. Department of Commerce Carlos M. Gutierrez, Secretary National Institute of Standards and Technology James M. Turner, Acting Director National Institute of Standards and Technology Special Publication 811, 2008 Edition (Supersedes NIST Special Publication 811, April 1995 Edition) Natl. Inst. Stand. Technol. Spec. Publ. 811, 2008 Ed., 85 pages (March 2008; 2nd printing November 2008) CODEN: NSPUE3 Note on 2nd printing: This 2nd printing dated November 2008 of NIST SP811 corrects a number of minor typographical errors present in the 1st printing dated March 2008. Guide for the Use of the International System of Units (SI) Preface The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. Long the dominant measurement system used in science, the SI is becoming the dominant measurement system used in international commerce. The Omnibus Trade and Competitiveness Act of August 1988 [Public Law (PL) 100-418] changed the name of the National Bureau of Standards (NBS) to the National Institute of Standards and Technology (NIST) and gave to NIST the added task of helping U.S.
    [Show full text]
  • The Equation of Radiative Transfer How Does the Intensity of Radiation Change in the Presence of Emission and / Or Absorption?
    The equation of radiative transfer How does the intensity of radiation change in the presence of emission and / or absorption? Definition of solid angle and steradian Sphere radius r - area of a patch dS on the surface is: dS = rdq ¥ rsinqdf ≡ r2dW q dS dW is the solid angle subtended by the area dS at the center of the † sphere. Unit of solid angle is the steradian. 4p steradians cover whole sphere. ASTR 3730: Fall 2003 Definition of the specific intensity Construct an area dA normal to a light ray, and consider all the rays that pass through dA whose directions lie within a small solid angle dW. Solid angle dW dA The amount of energy passing through dA and into dW in time dt in frequency range dn is: dE = In dAdtdndW Specific intensity of the radiation. † ASTR 3730: Fall 2003 Compare with definition of the flux: specific intensity is very similar except it depends upon direction and frequency as well as location. Units of specific intensity are: erg s-1 cm-2 Hz-1 steradian-1 Same as Fn Another, more intuitive name for the specific intensity is brightness. ASTR 3730: Fall 2003 Simple relation between the flux and the specific intensity: Consider a small area dA, with light rays passing through it at all angles to the normal to the surface n: n o In If q = 90 , then light rays in that direction contribute zero net flux through area dA. q For rays at angle q, foreshortening reduces the effective area by a factor of cos(q).
    [Show full text]
  • Atomic Layer Etching of Metal Oxides and Atomic Layer Deposition of Metal Fluorides
    Atomic Layer Etching of Metal Oxides and Atomic Layer Deposition of Metal Fluorides by Younghee Lee B.S., Seoul National University, l999 M.S., Seoul National University, 2001 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement for the degree of Doctor of Philosophy Department of Chemistry and Biochemistry 2015 This thesis entitled: Atomic Layer Etching of Metal Oxides and Atomic Layer Deposition of Metal Fluorides written by Younghee Lee has been approved for the Department of Chemistry and Biochemistry Professor Steven M. George Professor Carl A. Koval Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. iii Lee, Younghee (Ph.D., Chemistry) Atomic Layer Etching of Metal Oxides and Atomic Layer Deposition of Metal Fluorides Thesis directed by Professor Steven M. George Atomic control of thin film growth and removal is essential for semiconductor processing. Atomic layer deposition (ALD) is a thin film deposition technique that is based on self-limiting surface reactions that deposit thin conformal films with atomic scale precision. The ALD of metal fluorides has been limited by the difficulty of handling the hydrogen fluoride (HF) precursor that is necessary for metal fluoride film growth. The use of HF-pyridine as an HF reservoir has allowed the development of metal fluoride ALD processes such as AlF3, LiF, lithium ion conducting (AlF3)(LiF)x alloy, ZrF4, HfF4, MnF2, MgF2, and ZnF2.
    [Show full text]