1、g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3American National Standard forMetric Practice g3Co-SponsorsASTM Committee E43 on SI Practice andIEEE Standards Coordinating Committee 14 (Quantities, Units, and Letter Symbols) IEEE 3 Park Avenue New York, NY 10016-5997 USA11 April 2011 IEEE/ASTM SI 10-2010g3g3g3g3g3g3g
2、3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3g3(Revisiong3ofg3g3g3g3g3g3g3g3g3g3g3g3g3g3g3IEEE/ASTMg3SIg310g4862002)Recognized as an IEEE/ASTM SI 10TM-2010 American National Standard (ANSI) (Revision of IEEE/ASTM SI 10-2002) American National Standard for Metric Practice Co-Sponsor
3、s ASTM Committee E43 on SI Practice and IEEE Standards Coordinating Committee 14 (Quantities, Units, and Letter Symbols) Approved 8 December 2010 IEEE-SA Standards Board Approved 1 March 2011 ASTM International Approved 1 March 2011 American National Standards Institute Abstract: Guidance for the us
4、e of the modern metric system is given. Known as the International System of Units (abbreviated SI), the system is the basis for worldwide standardization of measurement units. Information is included on SI, a list of units recognized for use with SI, and a list of conversion factors, together with
5、general guidance on proper style and usage. Keywords: conversion factors, International System, International System of Units, metric practice, metric system, rounding, SI, SI 10, Systme International dUnits The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 1001
6、6-5997, USA ASTM International 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA Copyright 2011 by the Institute of Electrical and Electronics Engineers, Inc. and ASTM International All rights reserved. Published 11 April 2011. Printed in the United States of America. SECON
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20、ce Center. vi Copyright 2011 IEEE/ASTM. All rights reserved. IntroductionThis introduction is not part of IEEE/ASTM SI10-2011, American National Standard for Metric Practice. This document, which supersedes IEEE/ASTM SI10-2002, is the primary American National Standard for use of the International S
21、ystem of Units (SI). The first version of this standard that was published jointly by the IEEE and ASTM appeared in 1976. The sponsoring societies welcome comments and suggestions from interested individuals and organizations. In 1988, the Metric Conversion Act was amended to designate “the metric s
22、ystem of measurement as the preferred system of weights and measures for United States trade and commerce.” With the increasing importance of the global marketplace, it has become imperative for U.S. industry to extend its use of SI and for U.S. citizens to gain a working knowledge of this modern me
23、tric system. This standard is intended to give authoritative information on SI and appropriate guidance concerning its application. SI is defined in the document Le Systme International dUnits, published in French, with an English translation, by the International Bureau of Weights and Measures (BIP
24、M). The BIPM was set up by the Convention du Mtre, signed in 1875 (see Annex D). Le Systme International dUnits, known informally as the “BIPM SI Brochure,” is revised from time to time in accordance with the decisions of the General Conference on Weights and Measures (CGPM) and other international
25、organizations. A U.S. version is published by NIST B22.aThis standard is consistent with the SI brochure in all matters that concern the SI itself, except that it presents the degree Celsius as simply another name for the kelvin that is used to express Celsius temperature, while the BIPM SI Brochure
26、 lists the degree Celsius as an SI derived unit. Of more practical importance is the difference in approach to non-SI units. IEEE/ASTM SI10 and its predecessors have traditionally been more restrictive in their recommendations concerning the use of non-SI units. The SI Brochure, for example, lists t
27、he ngstrm as a unit that is “currently accepted for use with the International System” and lists the centimeter-gram-second (CGS) units and many others as units whose use “is not encouraged.” IEEE/ASTM SI10, which is intended for the United States and developed under the consensus standardization pr
28、ocess, makes the significantly stronger recommendation that these units are “not to be used.” Notice to users Laws and regulations Users of these documents should consult all applicable laws and regulations. Compliance with the provisions of this standard does not imply compliance to any applicable
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39、nformation may be obtained from the IEEE Standards Association. viii Copyright 2011 IEEE/ASTM. All rights reserved. Participants This standard was developed by the IEEE/ASTM Committee for Maintaining IEEE/ASTM SI 10, a joint committee established by the sponsoring organizations. The proposed standar
40、d generated by this joint committee was then formally adopted by the IEEE and ASTM before transmission to the American National Standards Institute for approval as an American National Standard. At the time of the approval of this revision, the joint committee had the following membership. Nonvoting
41、 members at the time of publication are marked with an asterisk (*): Bruce Barrow, Chair James R. Frysinger, Vice Chair Robert H. Bushnell, Secretary Nancy Bale Dennis Brownridge* Rodney Conn* Anthony French Uri Gat Stan Jakuba Bill Potts Howard Ressel* John T. Scott Ralph Showers* Barry N. Taylor*
42、Ambler Thompson Paul Trusten* Gerry Uttrachi* Matthew Zotter* ix Copyright 2011 IEEE/ASTM. All rights reserved. Contents 1. Overview 1 1.1 Scope . 1 1.2 Introduction 1 2. SI units and symbols . 2 2.1 Classes of units 2 2.2 SI prefixes 6 3. Use of the SI . 7 3.1 General . 7 3.2 Application of SI pref
43、ixes 7 3.3 Other units . 9 3.4 Some comments concerning quantities and units 13 3.5 Style and usage 16 Annex A (informative) Tables of conversion factors . 20 Annex B (informative) Rules for conversion and rounding . 44 Annex C (informative) Comments concerning the application of the International S
44、ystem of Units (SI) 50 Annex D (informative) Development of the International System of Units (SI) 55 Annex E (informative) Bibliography 58 Index . 60 1 Copyright 2011 IEEE/ASTM. All rights reserved. American National Standard for Metric Practice IMPORTANT NOTICE: This standard is not intended to en
45、sure safety, security, health, or environmental protection. Implementers of the standard are responsible for determining appropriate safety, security, environmental, and health practices or regulatory requirements. This IEEE document is made available for use subject to important notices and legal d
46、isclaimers. These notices and disclaimers appear in all publications containing this document and may be found under the heading “Important Notice” or “Important Notices and Disclaimers Concerning IEEE Documents.” They can also be obtained on request from IEEE or viewed at http:/standards.ieee.org/I
47、PR/disclaimers.html. 1. Overview 1.1 Scope This document is the primary American National Standard on application of the metric system. It emphasizes use of the International System of Units (SI), which is the modern, internationally accepted metric system. It includes information on SI, a limited l
48、ist of units recognized for use with SI, and a list of conversion factors, together with general guidance on style and usage. It also lists older “metric” units that shall no longer be used. The word “primary” implies that other metric standards in the United States should be consistent with this do
49、cument. 1.2 Introduction Any measurable physical quantity can be represented in the SI with the aid of just seven “base units”the units for the quantities length, mass, time, electric current, temperature, amount of substance, and luminous intensityor by combinations (called “derived units”) of these seven. For example, the unit of speed can be expressed by the unit of length divided by the unit of time. This standard shows first the two classes of units (base and derived) that make up the SI, together with the standard symbols that may be used to rep
